Search

Background: Lower functioning and higher symptom severity are observed when panic disorder (PD) co-occurs with generalized anxiety disorder (PD + GAD). No research on cortical gyrification patterns in the PD + GAD group has been conducted to date, which could show the alterations in brain connectivity in the extended fear network (EFN). This study aimed to investigate the characteristics of cortical gyrification in the PD + GAD group, compared to that in the PD without comorbid GAD (PD-GAD) group., Methods: This study included 90 patients with PD, with propensity score matching between the PD + GAD (n = 30) and PD-GAD groups (n = 60), and 65 healthy controls (HC). For clinical evaluation, we assessed the anxiety symptomatology, suicidality, and harm avoidance. The local gyrification index (LGI) was obtained from T1-weighted brain MRI data using FreeSurfer., Results: In the PD group compared to the HC, the hypergyrification involved the EFN. In the PD + GAD group compared to the PD-GAD group, hypergyrification was shown in the pathological worry-related brain regions. Within the PD + GAD group, significant positive correlations were observed between the superior frontal gyrus LGI values and suicidality scores, as well as between the superior parietal gyrus LGI values and harm avoidance levels., Limitations: Given the variability in cortical gyrification patterns, longitudinal studies are needed to assess the occurrence of hypergyrification in specific brain regions., Conclusions: This study is the first to demonstrate cortical gyrification patterns in the PD + GAD group compared to those in the PD-GAD group. Notably, the EFN and pathological worry-related brain regions have been implicated in the pathology of PD + GAD., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Previous studies have used machine learning to identify clinically relevant atrophic regions in progressive supranuclear palsy (PSP). This study applied Elastic Net (EN) in PSP to uncover key atrophic patterns, offering a novel approach to understanding its pathology., Methods: This study included baseline data from 74 patients with PSP enrolled in the Study of Comprehensive ANd multimodal marker-based cohort of PSP (SCAN-PSP, NCT05579301) in Seoul between January 2022 and August 2023. Participants were evaluated with PSP-rating scale (PSPRS) and Schwab & England Activity of daily living (SEADL). EN regression was used to identify regions with high explanatory power for clinical outcomes, which were combined with clinical parameters to build prediction models. Features selected from EN classification were applied to discriminate between the two groups., Results: EN identified the third ventricle, right anterior cingulate cortex, and left lateral orbitofrontal cortex as significant features, and multivariate linear regression models incorporating these regions with clinical variables showed high explainability for PSPRS (adjusted R 2  = 0.62) and SEADL (adjusted R 2  = 0.74). The EN-predicted values demonstrated strong correlation with actual scores of PSPRS (r = 0.75, p = 2·10 -14 ) and SEADL (r = 0.82, p = 2·10 -19 ). The combined EN-selected features and clinical parameters model robustly distinguished PSP-Richardson from the subcortical types (AUC = 0.94) and those with severe downgaze palsy from without (AUC = 0.90)., Conclusion: This study demonstrated that EN effectively identified significant regional atrophies in PSP, with a modest sample size. Future studies could incorporate multimodal analysis to identify markers for monitoring disease progression., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier Ltd. All rights reserved.)

Schizophrenia and attention deficit hyperactivity disorder (ADHD) have many contradicting features, but both these disorders share inattention as a core symptom. This study explored how the characteristics of inattention differ between the two disorders. 20 patients with schizophrenia, 20 patients with adult ADHD and 20 healthy controls participated in this study. Comprehensive attention test, Korean Wechsler adult intelligence scale-IV and resting-state functional magnetic resonance imaging (fMRI) were collected, among other things. The schizophrenia and ADHD groups showed low and high levels of functional connectivity in the default mode network (DMN), respectively. Functional connectivity level within the DMN was also positively correlated with processing speed index in the schizophrenia group and positively correlated with the number of divided-attention commission errors in the ADHD group. These results show that schizophrenia and adult ADHD have similarities in the characteristics of attention deficit, in that both may arise from dysregulation within the DMN. However, the differences in the levels of functional connectivity in the DMN between these groups affect how inattention manifests in each group., Competing Interests: Declaration of competing interest There is no conflict of interest to declare., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Background: Hippocampal atrophy is implicated in the early onset of Alzheimer's disease (AD). It is closely associated with rapid cognitive decline and serves as a critical predictor for conversion from mild cognitive impairment (MCI) to AD. Consequently, with growing interest in utilizing hippocampal volume (HV) as an outcome measure in clinical trials, elucidating the neurobiological mechanisms underlying hippocampal atrophy is essential for early diagnosing AD and predicting its progression., Objective: The risk of AD associated with the apolipoprotein E ε4 ( APOE4 ) allele is higher in females than in males. However, the presence of sex-specific effects of the APOE4 genotype on longitudinal hippocampal atrophy (ΔHV) remains unclear. We aimed to examine the effects of the interaction between the APOE4 genotype and sex on ΔHV in amnestic mild cognitive impairment (aMCI)., Methods: This hospital-based prospective longitudinal study included 73 patients with aMCI. ΔHV, the major outcome measure, was assessed using magnetic resonance imaging performed at a baseline date and 2 years after the baseline evaluation. A two-way analysis of variance was conducted to examine the effects of the interaction between the APOE4 genotype and sex on ΔHV over the 2-year period., Results: A significant interaction was observed between APOE4 and sex concerning ΔHV ( p  = 0.036). In females, ΔHV significantly correlated with the APOE4 status. Female APOE4 carriers (ε3/ε4) exhibited 2.3 times higher ΔHV compared with female non-carriers (ε3/ε3) (-0.51 ± 0.28 versus -0.22 ± 0.26, p  < 0.001). In contrast, ΔHV was not linked to the APOE4 status in males ( p  = 0.599)., Conclusions: We identified that the APOE4 genotype affected ΔHV in females. Our findings suggest that female APOE4 carriers, unlike males, may be more susceptible than non-carriers to the underlying pathophysiological mechanisms of hippocampal atrophy in aMCI., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Although previous studies have shown that cognitive decline in Alzheimer's disease (AD) is associated with various risk factors, they primarily focused on late-onset AD (LOAD)., Objective: We aim to evaluate the differential impact of risk factors on the cognitive decline between early-onset AD (EOAD, onset < 65 years) and LOAD (onset ≥ 65 years) and explore the longitudinal effect of Apolipoprotein E allele 4 ( APOE ε4) on cortical atrophy in both cohorts., Methods: Using data from 212 EOAD and 1101 LOAD participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI), we conducted multivariable mixed-effect models to evaluate the impact of APOE ε4, education, hypertension, diabetes, dyslipidemia, and body mass index on cognitive performance. Preprocessed MRI data were utilized for longitudinal parametric mapping., Results: APOE ε4 carriers in both groups showed significantly accelerated declines in language, verbal memory, executive function, and general cognition. By controlling other significant risk factors, APOE ε4 carriers showed faster declines in language and verbal memory in both groups. Females exhibited accelerated declines in Language and verbal memory in the EOAD and LOAD cohorts respectively. LOAD individuals with hypertension showed faster declines while overweight and obese participants displayed slower declines in both cohorts across all domains except visuospatial. Notably, APOE ε4 status was associated with longitudinal cortical atrophy in the LOAD cohort but not in the EOAD cohort., Conclusions: Known risk factors for AD were associated with cognitive decline in both EOAD and LOAD cohorts., Competing Interests: Declaration of conflicting interestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: L.G.A. has provided consultation to Eli Lilly, Biogen, Genentech, GE Healthcare, Eisai, Roche Diagnostics, Siemens, Alnylam, Corium, Otsuka, Two Labs, FL Dept Health, and the NIH Biobank. LGA receives the following research support: NIA U01 AG057195, NIA R01 AG057739, NIA P30 AG010133, Alzheimer Association LEADS GENETICS 19-639372, Alzheimer Association SG-23-1061716, Roche Diagnostics RD005665, AVID Pharmaceuticals and Life Molecular Imaging. LGA has received honoraria for participating in independent data safety monitoring boards and providing educational CME lectures and programs.

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare white matter disease characterized by axonal and glial injury. Although its clinical characteristics have been described in case reports, the prevalence of CSF1R mutations in clinically suspected ALSP cases remains unclear. Herein, we analysed the frequency of CSF1R mutations in patients with probable or possible ALSP and describe the genetic, clinical, radiological, and pathological findings of ALSP cases in individuals of Korean ancestry. Twenty-eight patients with probable or possible ALSP diagnosed at Samsung Medical Center, Seoul, between January 2014 and August 2020, were retrospectively reviewed. All participants underwent brain magnetic resonance imaging (MRI) and CSF1R genetic testing. Overall, 9 of the 28 patients (32.1%) [5/6 (83.3%) of probable ALSP and 4/22 (18.2%) of possible ALSP] were confirmed to have pathogenic or likely pathogenic variants in CSF1R gene. Additionally, one patient without CSF1R mutation exhibited histopathological findings consistent with ALSP on brain biopsy. All patients with CSF1R mutation presented with cognitive impairment and/or psychiatric symptoms. Brain MRI revealed bilateral white matter hyperintensities in all patients, and 5/8 (62.5%) showed diffusion-restricted lesions. Notably, patients with CSF1R mutation had younger age at onset, rapidly progressive course, and diffuse hyperintensity in the splenium compared to patients without CSF1R mutation. Our findings suggest that for definite diagnosis, CSF1R genetic testing is recommended in patients who meet the diagnostic criteria for possible or probable ALSP. Our findings provide insights into the genetic, clinical, radiological, and pathological dimensions of ALSP in individuals of Korean ancestry., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Head and neck paragangliomas (HNPGLs) are typically slow-growing, hormonally inactive tumors of parasympathetic paraganglia. Inactivation of prolyl-hydroxylase domain-containing 2 protein causing indirect gain-of-function of hypoxia-inducible factor-2α (HIF-2α), encoded by EPAS1, was recently shown to cause carotid body hyperplasia. We previously described a syndrome with multiple sympathetic paragangliomas caused by direct gain-of-function variants in EPAS1 (Pacak-Zhuang syndrome, PZS) and developed a corresponding mouse model., Methods: We evaluated a cohort of patients with PZS (n = 9) for HNPGL by positron emission tomography, magnetic resonance imaging, and computed tomography and measured carotid body size compared to literature reference values. Resected tumors were evaluated by histologic sectioning and staining. We evaluated the corresponding mouse model at multiple developmental stages (P8 and adult) for lesions of the head and neck by high resolution ex vivo imaging and performed immunohistochemical staining on histologic sections of the identified lesions., Results: hree patients had imaging consistent with HNPGL, one of which warranted resection and was confirmed on histology. Three additional patients had carotid body enlargement (Z-score > 2.0), and 3 had carotid artery malformations. We found that 9 of 10 adult variant mice had carotid body tumors and 6 of 8 had a paraganglioma on the cranio-caval vein, the murine homologue of the superior vena cava; these were also found in 4 of 5 variant mice at post-natal day 8. These tumors and the one resected from a patient were positive for tyrosine hydroxylase, synaptophysin, and chromogranin A. Brown fat in a resected patient tumor carried the EPAS1 pathogenic variant., Conclusions: These findings (1) suggest HNPGL as a feature of PZS and (2) show that these pathogenic variants are sufficient to cause the development of these tumors, which we believe represents a continuous spectrum of disease starting from hyperplasia., (Published by Oxford University Press 2025.)

In breast-conserving surgery (BCS), clear resection margins are crucial to prevent recurrence. Accurate imaging is vital for precise BCS, with MRI being the most accurate. However, MRI has limitations in identifying the exact extent of breast cancer in patients who have undergone neoadjuvant chemotherapy (NACT). A 3D-Printed Breast Surgical Guide (3DP-BSG) can address this issue by effectively pinpointing cancer extent in NACT patients, thus enhancing surgical accuracy. This retrospective single-institution cohort study focused on female patients diagnosed with invasive breast cancer who underwent NACT. Between November 2015 and October 2021, patients received BCS with the aid of a 3DP-BSG. Personalized 3DP-BSG targeted tumors by tracking changes in breast and tumor anatomy on MRI before and after NACT. 203 patients with invasive breast cancer were enrolled in the study. According to exclusion criteria, 197 patients were analyzed. The median follow-up period was 35.3 months (range: 2.2-96.8 months). 3 patients (1.5%) had positive resection margins. During the follow-up period, 17 patients (8.6%) experienced recurrence, with one patient (0.5%) confirmed local recurrences. The application of MRI-based 3DP-BSG is effective in achieving low positive margins and local recurrence in patients undergoing BCS after NACT, offering a promising approach for improving surgical outcomes., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Inflammatory myopathy is generally categorized into generalized inflammatory myopathies (gIM), which affect muscles throughout the body, and focal inflammatory myopathies (fIM), which are localized to specific muscles or muscle groups. This report details a case of immune-mediated polymyositis in a dog, successfully diagnosed using MRI and IHC and managed with immunosuppressive therapy., Case Presentation: A 5-year-old castrated male Poodle was admitted to our hospital presenting with lethargy and exercise intolerance. Biochemical analysis revealed significantly elevated serum levels of aspartate aminotransferase (AST) and creatine kinase (CK). Physical examination showed muscle atrophy in the hind legs, but further orthopedic and neurological examinations identified no additional abnormalities. MRI demonstrated hyperintense and heterogeneous signal changes across the muscles, including contrast enhancement, suggesting inflammatory myopathy. This diagnosis was confirmed through histopathological examination, which revealed inflammatory lesions with fibrous tissue proliferation within the muscle tissue. To investigate the presence and type of inflammatory cells and vascular changes, aiding in the differential diagnosis of inflammatory myopathies, immunohistochemistry (IHC) was performed, revealing positive findings for CD8 + , CD4 + , and VEGF in the evaluated tissue, leading to a diagnosis of polymyositis., Conclusions: The dog was diagnosed with immune-mediated polymyositis and treatment was initiated with prednisolone at 1 mg/kg twice daily and azathioprine at 2 mg/kg once daily. Following the administration of these immunosuppressive agents, CK levels returned to normal, and the dog's exercise intolerance and lethargy resolved. The thickness of the hind legs also increased progressively. The dog has maintained an improved condition under continued immunosuppressive therapy for four months. This case highlights the critical role of MRI and immunohistochemistry in diagnosing immune-mediated polymyositis, demonstrating their alternative capability in cases where conventional electromyography (EMG) is not feasible in this context., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Written informed consent was obtained from the dog’s owner. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Study Design: A retrospective cohort study., Objective: To evaluate the mid-term effect of intervertebral disc degeneration (DD) in patients with adolescent idiopathic scoliosis (AIS) who underwent pedicle screw instrumentation (PSI) and rod derotation (RD) with direct vertebral rotation (DVR)., Summary of Background Data: Posterior spinal fusion is a mainstay of surgical treatment in AIS, and DVR is considered a main corrective maneuver for vertebral rotation. However, the mid-term effect of intervertebral DD after DVR is still unknown in AIS., Methods: A total of 336 vertebrae for 48 patients with AIS who underwent PSI and RD with DVR were retrospectively assessed for intervertebral DD. They were divided into two groups based upon intervertebral DD, defined as Pfirmann grade more than IV. The Pfirrmann grade and modic change were evaluated at the disc above the uppermost instrumented vertebra (UIV), the disc below the lowest instrumented vertebra (LIV), and the lumbar disc levels., Results: With the 11.6 years of mean follow-up, 41.7% (20/48) of patients exhibited DD, while modic changes were observed in 4.2% (2/48) of the included patients. The discs below the LIV, L4-5, and L5-S1 were significantly shown to have an increasing trend of Pfirmann grade. The preoperative thoracic kyphosis was significantly lower in the DD group (22.0°) than in the non-DD group (31.4°) ( P = 0.025) and negatively correlated with DD ( r = -0.482, P = 0.018). The Pfirrmann grade of L5-S1 showed a high level of correlation with DD ( r = 0.604, P < 0.001)., Conclusions: The degenerative change at the disc below the LIV, L4-5, and L5-S1 levels was observed following PSI and RD with DVR. Thoracic hypokyphosis may negatively influence intervertebral discs in patients with AIS required for deformity correction. Therefore, the restoration of thoracic kyphosis is important to prevent long-term DD in AIS., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: CSF1R-related leukoencephalopathy is a type of autosomal dominant leukodystrophy caused by mutations in the colony stimulating factor 1 receptor (CSF1R) gene. Subcortical ischemic vascular dementia (SIVaD), which is caused by cerebral small vessel disease, is similar to CSF1R-related leukoencephalopathy in that it mainly affects subcortical white matter. In this study, we compared the patterns of white matter hyperintensity (WMH) and cortical thickness in CSF1R-related leukoencephalopathy with those in SIVaD., Methods: Fourteen patients with CSF1R-related leukoencephalopathy and 129 with SIVaD were retrospectively recruited from three tertiary medical centers. We extracted and visualized WMH data using voxel-based morphometry to compare the WMH distributions between the two groups. Cortical thickness was measured using a surface-based method. Statistical maps of differences in cortical thickness between the two groups were generated using a surface model, with age, sex, education, and intracranial volume as covariates., Results: Predominant distribution of WMH in the CSF1R-related leukoencephalopathy group was in the bilateral frontal and parietal areas, whereas the SIVaD group showed diffuse WMH involvement in the bilateral frontal, parietal, and temporal areas. Compared with the SIVaD group, the CSF1R-related leukoencephalopathy group showed more severe corpus callosum atrophy (CCA) and widespread cortical thinning., Conclusions: To our knowledge, this is the first study using the automated MR measurement to capture WMH, cortical thinning, and CCA with signal changes in CSF1R-related leukoencephalopathy. It provides new evidence regarding differences in the patterns of WMH distribution and cortical thinning between CSF1R-related leukoencephalopathy and SIVaD., Competing Interests: NO authors have competing interests., (Copyright: © 2024 Kim et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Understanding brain function is essential for advancing our comprehension of human cognition, behavior, and neurological disorders. Magnetic resonance imaging (MRI) stands out as a powerful tool for exploring brain function, providing detailed insights into its structure and physiology. Combining MRI technology with electrophysiological recording system can enhance the comprehension of brain functionality through synergistic effects. However, the integration of neural implants with MRI technology presents challenges because of its strong electromagnetic (EM) energy during MRI scans. Therefore, MRI-compatible neural implants should facilitate detailed investigation of neural activities and brain functions in real-time in high resolution, without compromising patient safety and imaging quality. Here, we introduce the fully MRI-compatible monolayer open-mesh pristine PEDOT:PSS neural interface. This approach addresses the challenges encountered while using traditional metal-based electrodes in the MRI environment such as induced heat or imaging artifacts. PEDOT:PSS has a diamagnetic property with low electrical conductivity and negative magnetic susceptibility similar to human tissues. Furthermore, by adopting the optimized open-mesh structure, the induced currents generated by EM energy are significantly diminished, leading to optimized MRI compatibility. Through simulations and experiments, our PEDOT:PSS-based open-mesh electrodes showed improved performance in reducing heat generation and eliminating imaging artifacts in an MRI environment. The electrophysiological recording capability was also validated by measuring the local field potential (LFP) from the somatosensory cortex with an in vivo experiment. The development of neural implants with maximized MRI compatibility indicates the possibility of potential tools for future neural diagnostics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: Dual-layer CT (DLCT) can create virtual monochromatic images (VMIs) at various monochromatic X-ray energies, particularly at low keV levels, with high contrast-to-noise ratio. The purpose of this study was to assess the clinical feasibility of contrast-enhanced chest DLCT with a low keV VMI for preoperative breast cancer staging, in comparison to breast MRI., Materials and Methods: A total of 152 patients with 155 index breast cancers were enrolled in the study. VMIs were generated from contrast-enhanced chest DLCT at 40 keV and maximum intensity projection (MIP) with three-dimensional (3D) reconstruction was performed for both bilateral breast areas. Two radiologists reviewed in consensus the 3D MIP images of the chest DLCT with VMI and breast MRI in separate sessions with a 3-month wash-out period. The detection rate and mean tumor size of the index cancer were compared between the chest DLCT with VMI and breast MRI. Additionally, the agreement of tumor size measurement between the two imaging modalities were evaluated., Results: Of all index cancers, 84.5% (131/155) were detected in the chest DLCT with VMI, while 88.4% (137/155) were detected in the breast MRI ( P = 0.210). The Bland-Altman agreement between the chest DLCT with VMI and breast MRI was a mean difference of -0.05 cm with 95% limits of agreement of -1.29 to 1.19 cm. The tumor size in the chest DLCT with VMI (2.3 ± 1.7 cm) was not significantly different from that in the breast MRI (2.4 ± 1.6 cm) ( P = 0.106)., Conclusion: The feasibility of chest DLCT with VMI was demonstrated for preoperative tumor staging in breast cancer patients, showing comparable cancer detectability and good agreement in tumor size measurement compared to breast MRI. This suggests that chest DLCT with VMI can serve as a potential alternative for patients who have contraindications to breast MRI., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2024 The Korean Society of Radiology.)

Background: Positron emission tomography (PET) has been reported as effective in diagnosing peripheral nerve injury (PNI). However, there is a lack of studies evaluating different degrees of PNI using PET within the same individual to reduce errors due to interindividual differences., Purpose: To evaluate the recovery process in the same rat after sciatic nerve injury using PET/magnetic resonance imaging (MRI)., Material and Methods: Crushing nerve injuries were induced in the left sciatic nerves of six male rats, preserving the right ones. The degree of nerve damage was measured at one, two, three, four, and five weeks postoperatively using three assessment methods: paw withdrawal threshold test ( RevWT ); PET ( SUVR ); and MRI ( MRSIR ). All the representing values of each method are presented as ratio values of the right and left sides in each rat., Results: Significant gradual recovery of all rats was observed over time in all the methods. No significant differences in RevWT and MRSIR were observed between before and more than four weeks after injury, whereas a significant difference in SUVR was still observed between before and five weeks after injury ( P  = 0.0007). The parameters of all methods decreased significantly over time ( P  = 0.000, all), and the explanatory power was significant in RevWT , SUVR , and MRSIR ., Conclusion: PET and MRI could be valuable non-invasive techniques for diagnosing neuropathic pain resulting from PNI. PET/MRI would be expected to be a more accurate and informative diagnostic tool for PNI than MRI alone., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: This study examined the relationship between structural brain networks and long-term treatment outcomes in patients with panic disorder (PD) using machine learning methods., Method: The study involved 80 participants (53 PD patients and 27 healthy controls) and included clinical assessments and MRI scans at baseline and after two years (160 MRIs). Patients were categorized based on their response to two-year pharmacotherapy. Brain networks were analyzed using white matter tractography and network-based statistics., Results: Results showed structural network changes in PD patients, particularly in the extended fear network, including frontal regions, thalamus, and cingulate gyrus. Longitudinal analysis revealed that increased connections to the amygdala, hippocampus, and insula were associated with better treatment response. Conversely, overconnectivity in the amygdala and insula at baseline was associated with poor response, and similar patterns were found in the insula and parieto-occipital cortex related to non-remission. This study found that SVM and CPM could effectively predict treatment outcomes based on network pattern changes in PD., Conclusions: These findings suggest that monitoring structural connectome changes in limbic and paralimbic regions is critical for understanding PD and tailoring treatment. The study highlights the potential of using personalized biomarkers to develop individualized treatment strategies for PD., Competing Interests: Declaration of Competing Interest All authors declare that this study was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: To analyze the characteristics of spinal metastasis in CT scans across diverse cancers for effective diagnosis and treatment, using MRI as the gold standard., Methods: A retrospective study of 309 patients from four centers, who underwent concurrent CT and spinal MRI, revealing spinal metastasis, was conducted. Data on metastasis including total number, volume, visibility on CT (visible, indeterminate, or invisible), and type of bone change were collected. Through chi-square and Mann-Whitney U tests, we characterized the metastasis across diverse cancers and investigated the variation in the intra-individual ratio representing the percentage of lesions within each category for each patient., Results: Out of 3333 spinal metastases from 309 patients, 55% were visible, 21% indeterminate, and 24% invisible. Sclerotic and lytic lesions made up 47% and 43% of the visible and indeterminate categories, respectively. Renal cell carcinoma (RCC), prostate cancer, and hepatocellular carcinoma (HCC) had the highest visibility at 86%, 73%, and 67% (p < 0.0001, p < 0.0001, and p = 0.003), while pancreatic cancer was lowest at 29% (p < 0.0001). RCC and HCC had significantly high lytic metastasis ratios (interquartile range (IQR) 0.96-1.0 and 0.31-1.0, p < 0.001 and p = 0.005). Prostate cancer exhibited a high sclerotic lesion ratio (IQR 0.52-0.97, p < 0.001). About 39% of individuals had invisible or indeterminate lesions, even with a single visible lesion on CT. The intra-individual ratio for indeterminate and invisible metastases surpassed 18%, regardless of the maximal size of the visible metastasis., Conclusions: This study highlights the variability in characteristics of spinal metastasis based on the primary cancer type through unique lesion-centric analysis., (© 2024. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Evaluating the performance of a binary diagnostic test, including artificial intelligence classification algorithms, involves measuring sensitivity, specificity, positive predictive value, and negative predictive value. Particularly when comparing the performance of two diagnostic tests applied on the same set of patients, these metrics are crucial for identifying the more accurate test. However, comparing predictive values presents statistical challenges because their denominators depend on the test outcomes, unlike the comparison of sensitivities and specificities. This paper reviews existing methods for comparing predictive values and proposes using the permutation test. The permutation test is an intuitive, non-parametric method suitable for datasets with small sample sizes. We demonstrate each method using a dataset from MRI and combined modality of mammography and ultrasound in diagnosing breast cancer., Competing Interests: Seo Young Park, who holds the respective position of Statistical Consultant of the Korean Journal of Radiology, was not involved in the editorial evaluation or decision to publish this article. The remaining authors have declared no conflicts of interest., (Copyright © 2024 The Korean Society of Radiology.)

While deep brain stimulation (DBS) is widely employed for managing motor symptoms in Parkinson's disease (PD), its exact circuit mechanisms remain controversial. To identify the neural targets affected by therapeutic DBS in PD, we analyzed DBS-evoked whole brain activity in female hemi-parkinsonian rats using functional magnetic resonance imaging (fMRI). We delivered subthalamic nucleus (STN) DBS at various stimulation pulse repetition rates using optogenetics, allowing unbiased examination of cell-type specific STN feedforward neural activity. Unilateral optogenetic STN DBS elicited pulse repetition rate-dependent alterations of blood-oxygenation-level-dependent (BOLD) signals in SNr (substantia nigra pars reticulata), GP (globus pallidus), and CPu (caudate putamen). Notably, this modulation effectively ameliorated pathological circling behavior in animals expressing the kinetically faster Chronos opsin, but not in animals expressing ChR2. Furthermore, mediation analysis revealed that the pulse repetition rate-dependent behavioral rescue was significantly mediated by optogenetic DBS induced activity changes in GP and CPu, but not in SNr. This suggests that the activation of GP and CPu are critically involved in the therapeutic mechanisms of STN DBS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Iatrogenic mandibular nerve damage resulting from oral surgeries and dental procedures is painful and a formidable challenge for patients and oral surgeons alike, mainly because the absence of objective and quantitative methods for diagnosing nerve damage renders treatment and compensation ambiguous while often leading to medico-legal disputes. The aim of this study was to examine discriminating factors of traumatic mandibular nerve within a specific magnetic resonance imaging (MRI) protocol and to suggest tangible diagnostic criteria for peripheral trigeminal nerve injury., Methods: Twenty-six patients with ipsilateral mandibular nerve trauma underwent T2 Flex water, 3D short tau inversion recovery (STIR), and diffusion-weighted imaging (DWI) acquired by periodically rotating overlapping parallel lines with enhanced reconstruction (PROPELLER) pulse sequences; 26 injured nerves were thus compared with contra-lateral healthy nerves at anatomically corresponding sites. T2 Flex apparent signal to noise ratio (FSNR), T2 Flex apparent nerve-muscle contrast to noise ratio (FNMCNR) 3D STIR apparent signal to noise ratio (SSNR), 3D STIR apparent nerve-muscle contrast to noise ratio (SNMCNR), apparent diffusion coefficient (ADC) and area of cross-sectional nerve (Area) were evaluated., Results: Mixed model analysis revealed FSNR and FNMCNR to be the dual discriminators for traumatized mandibular nerve (p < 0.05). Diagnostic performance of both parameters was also determined with area under the receiver operating characteristic curve (AUC for FSNR = 0.712; 95% confidence interval [CI]: 0.5660, 0.8571 / AUC for FNMCNR = 0.7056; 95% confidence interval [CI]: 1.011, 1.112)., Conclusions: An increase in FSNR and FNMCNR within our MRI sequence seems to be accurate indicators of the presence of traumatic nerve. This prospective study may serve as a foundation for sophisticated model diagnosing trigeminal nerve trauma within large patient cohorts., (© 2024. The Author(s).)

Purpose: Vestibular schwannoma is a benign tumor originating from Schwann cells surrounding the eighth cranial nerve and can cause hearing loss, tinnitus, balance problems, and facial nerve disorders. Because of the slow growth of the tumor, predicting the hearing function of patients with vestibular schwannoma's is important to obtain information that would be useful for deciding the treatment modality. This study aimed to analyze the association between magnetic resonance imaging features and hearing status using a new radiomics technique., Methods: We retrospectively analyzed 115 magnetic resonance images and hearing results from 73 patients with vestibular schwannoma. A total of 70 radiomics features from each tumor volume were calculated using T1-weighted magnetic resonance imaging. Radiomics features were classified as histogram-based, shape-based, texture-based, and filter-based. The least absolute shrinkage and selection operator method was used to select the radiomics features among the 70 features that best predicted the hearing test. To ensure the stability of the selected features, the least absolute shrinkage and selection operator method was repeated 10 times. Finally, features set five or more times were selected as radiomics signatures., Results: The radiomics signatures selected using the least absolute shrinkage and selection operator method were: minimum, variance, maximum 3D diameter, size zone variance, log skewness, skewness slope, and kurtosis slope. In random forest, the mean performance was 0.66 (0.63-0.77), and the most important feature was Log skewness., Conclusions: Newly developed radiomics features are associated with hearing status in patients with vestibular schwannoma and could provide information when deciding the treatment modality., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To develop and evaluate a deep learning model for automated segmentation and detection of bone metastasis on spinal MRI., Materials and Methods: We included whole spine MRI scans of adult patients with bone metastasis: 662 MRI series from 302 patients (63.5 ± 11.5 years; male:female, 151:151) from three study centers obtained between January 2015 and August 2021 for training and internal testing (random split into 536 and 126 series, respectively) and 49 MRI series from 20 patients (65.9 ± 11.5 years; male:female, 11:9) from another center obtained between January 2018 and August 2020 for external testing. Three sagittal MRI sequences, including non-contrast T1-weighted image (T1), contrast-enhanced T1-weighted Dixon fat-only image (FO), and contrast-enhanced fat-suppressed T1-weighted image (CE), were used. Seven models trained using the 2D and 3D U-Nets were developed with different combinations (T1, FO, CE, T1 + FO, T1 + CE, FO + CE, and T1 + FO + CE). The segmentation performance was evaluated using Dice coefficient, pixel-wise recall, and pixel-wise precision. The detection performance was analyzed using per-lesion sensitivity and a free-response receiver operating characteristic curve. The performance of the model was compared with that of five radiologists using the external test set., Results: The 2D U-Net T1 + CE model exhibited superior segmentation performance in the external test compared to the other models, with a Dice coefficient of 0.699 and pixel-wise recall of 0.653. The T1 + CE model achieved per-lesion sensitivities of 0.828 (497/600) and 0.857 (150/175) for metastases in the internal and external tests, respectively. The radiologists demonstrated a mean per-lesion sensitivity of 0.746 and a mean per-lesion positive predictive value of 0.701 in the external test., Conclusion: The deep learning models proposed for automated segmentation and detection of bone metastases on spinal MRI demonstrated high diagnostic performance., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2024 The Korean Society of Radiology.)

Background and Objective: Cerebral vascular diseases are among the most burdensome diseases faced by society. However, investigating the pathophysiology of diseases as well as developing future treatments still relies heavily on expensive in-vivo and in-vitro studies. The generation of realistic, patient-specific models of the cerebrovascular system capable of simulating hemodynamics and perfusion promises the ability to simulate diseased states, therefore accelerating development cycles using in silico studies and opening opportunities for the individual assessment of diseased states, treatment planning, and the prediction of outcomes. By providing a patient-specific, anatomically detailed and validated model of the human cerebral vascular system, we aim to provide the basis for future in silico investigations of the cerebral physiology and pathology., Methods: In this retrospective study, a processing pipeline for patient-specific quantification of cerebral perfusion was developed and applied to healthy individuals and a stroke patient. Major arteries are segmented from 3T MR angiography data. A synthetic tree generation algorithm titled tissue-growth based optimization (GBO) 1 is used to extend vascular trees beyond the imaging resolution. To investigate the anatomical accuracy of the generated trees, morphological parameters are compared against those of 7 T MRI, 9.4 T MRI, and dissection data. Using the generated vessel model, hemodynamics and perfusion are simulated by solving one-dimensional blood flow equations combined with Darcy flow equations., Results: Morphological data of three healthy individuals (mean age 47 years ± 15.9 [SD], 2 female) was analyzed. Bifurcation and physiological characteristics of the synthetically generated vessels are comparable to those of dissection data. The inability of MRI based segmentation to resolve small branches and the small volume investigated cause a mismatch in the comparison to MRI data. Cerebral perfusion was estimated for healthy individuals and a stroke patient. The simulated perfusion is compared against Arterial-Spin-Labeling MRI perfusion data. Good qualitative agreement is found between simulated and measured cerebral blood flow (CBF) 2 . Ischemic regions are predicted well, however ischemia severity is overestimated., Conclusions: GBO successfully generates detailed cerebral vascular models with realistic morphological parameters. Simulations based on the resulting networks predict perfusion territories and ischemic regions successfully., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare that are relevant to the content of this article., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objective: The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state water-excitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI., Materials and Methods: This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESS-WE-MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors., Results: The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESS-WE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64-8.25] and 2.02 [95% CI: 0.32-12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19-16.75] and 1.94 [95% CI: 0.20-18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001)., Conclusion: Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2023 The Korean Society of Radiology.)

Background: We investigated the relevance of various imaging markers for the clinical trajectory of cerebral amyloid angiopathy (CAA) patients in a memory clinic., Methods: A total of 226 patients with probable CAA were included in this study with a mean follow-up period of 3.5 ± 2.7 years. Although all had more than one follow-up visit, 173 underwent follow-up Mini-Mental Status Examination (MMSE) and Clinical Dementia Rating Sum of Boxes (CDR-SB) ranging from 2 to 15 time points. Among 226, 122 patients underwent amyloid-β (Aβ) PET imaging. The prevalence of intracerebral hemorrhage (ICH) and its imaging predictors was investigated. The effects of CAA imaging markers and Aβ PET positivity on longitudinal cognition based on the MMSE and CDR-SB were evaluated using mixed effects models., Results: During the follow-up, 10 (4.4%) patients developed ICH: cortical superficial siderosis (cSS; hazard ratio [HR], 6.45) and previous lobar ICH (HR, 4.9), but lobar cerebral microbleeds (CMBs) were not predictors of ICH development. The presence of CMIs (p = 0.045) and Aβ positivity (p = 0.002) were associated with worse MMSE trajectory in CAA patients. Regarding CDR-SB trajectory, only Aβ positivity was marginally associated with worse longitudinal change (p = 0.050)., Conclusion: The results of the present study indicated that various imaging markers in CAA patients have different clinical relevance and predictive values for further clinical courses., (© 2023. The Author(s).)

Background: Decreased visual acuity (VA) is reported to be a risk factor for dementia. However, the association between VA and cortical thickness has not been established. We investigated the association between VA and cortical thickness in cognitively normal adults., Method: We conducted a cross-sectional, single-center cohort study with cognitively normal adults (aged ≥ 45) who received medical screening examinations at the Health Promotion Center at Samsung Medical Center. Subjects were categorized as bad (VA ≤ 20/40), fair (20/40 < VA ≤ 20/25), and good (VA > 20/25) VA group by using corrected VA in the Snellen system. Using 3D volumetric brain MRI, cortical thickness was calculated using the Euclidean distance between the linked vertices of the inner and outer surfaces. We analyzed the association between VA and cortical thickness after controlling for age, sex, hypertension, diabetes, dyslipidemia, intracranial volume, and education level., Results: A total of 2756 subjects were analyzed in this study. Compared to the good VA group, the bad VA group showed overall thinner cortex (p = 0.015), especially in the parietal (p = 0.018) and occipital (p = 0.011) lobes. Topographical color maps of vertex-wise analysis also showed that the bad VA group showed a thinner cortex in the parieto-temporo-occipital area. These results were more robust in younger adults (aged 45 to 65) as decreased VA was associated with thinner cortex in more widespread regions in the parieto-temporo-occipital area., Conclusion: Our results suggest that a thinner cortex in the visual processing area of the brain is related to decreased visual stimuli., (© 2022. The Author(s).)

Background: In the modern era of magnetic resonance imaging (MRI) staging, the benefit of prophylactic cranial irradiation (PCI) in patients with small-cell lung cancer (SCLC) has been controversial. This study evaluated the prognostic impact of PCI in patients with limited- or extensive-stage SCLC who had no brain metastases at diagnosis according to MRI., Methods: Data from newly diagnosed patients in 2014 from the Korean Association for Lung Cancer Registry database were used. Patients with limited- or extensive-stage SCLC who had no brain metastases according to MRI were identified. Univariate and multivariate survival analyses were conducted to assess the prognostic association of PCI., Results: Of 107 and 122 patients with limited- and extensive-stage SCLC, 24% and 14% received PCI, respectively. In the limited-stage SCLC group, the 2-year overall survival (OS) rates of patients who received PCI and those who did not were 50% and 29% (P = 0.018), respectively. However, there was no significant difference in OS for patients with extensive-stage SCLC (P = 0.336). After adjusting for other covariates, PCI was found to be associated with improved OS in the limited-stage SCLC group (P = 0.005). Based on the time-course hazard rate function plots in the limited-stage SCLC group, the OS benefit of PCI was maximized within the first year of follow-up., Conclusions: In the modern era of MRI staging, PCI might be beneficial for patients with limited-stage SCLC but not for those with extensive-stage SCLC. Further studies with a large sample size are needed to verify the prognostic association of PCI., (© 2022. The Author(s).)

Purpose: To validate the use of synthetic magnetic resonance imaging (SyMRI) volumetry by comparing with child-optimized SPM 12 volumetry in 3 T pediatric neuroimaging., Methods: In total, 106 children aged 4.7-18.7 years who underwent both synthetic and 3D T1-weighted imaging and had no abnormal imaging/neurologic findings were included for the SyMRI vs. SPM T1-only segmentation (SPM T1). Forty of the 106 children who underwent an additional 3D T2-weighted imaging were included for the SyMRI vs. SPM multispectral segmentation (SPM multi). SPM segmentation using an age-appropriate atlas and inverse-transforming template-space intracranial mask was compared with SyMRI segmentation. Volume differences between SyMRI and SPM T1 were plotted against age to evaluate the influence of age on volume difference., Results: Measurements derived from SyMRI and two SPM methods showed excellent agreements and strong correlations except for the CSF volume (CSFV) (intraclass correlation coefficients = 0.87-0.98; r = 0.78-0.96; relative volume difference other than CSFV = 6.8-18.5% [SyMRI vs. SPM T1] and 11.3-22.7% [SyMRI vs. SPM multi]). Dice coefficients of all brain tissues (except CSF) were in the range 0.78-0.91. The Bland-Altman plot and age-related volume difference change suggested that the volume differences between the two methods were influenced by the volume of each brain tissue and subject's age (p < 0.05)., Conclusion: SyMRI and SPM segmentation results were consistent except for CSFV, which supports routine clinical use of SyMRI-based volumetry in pediatric neuroimaging. However, caution should be taken in the interpretation of the CSF segmentation results., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Imaging of the electrical conductivity distribution inside the human body has been investigated for numerous clinical applications. The conductivity tensors of biological tissue have been obtained from water diffusion tensors by applying several models, which may not cover the entire phenomenon. Recently, a new conductivity tensor imaging (CTI) method was developed through a combination of B1 mapping, and multi-b diffusion weighted imaging. In this study, we compared the most recent CTI method with the four existing models of conductivity tensors reconstruction. Two conductivity phantoms were designed to evaluate the accuracy of the models. Applied to five human brains, the conductivity tensors using the four existing models and CTI were imaged and compared with the values from the literature. The conductivity image of the phantoms by the CTI method showed relative errors between 1.10% and 5.26%. The images by the four models using DTI could not measure the effects of different ion concentrations subsequently due to prior information of the mean conductivity values. The conductivity tensor images obtained from five human brains through the CTI method were comparable to previously reported literature values. The images by the four methods using DTI were highly correlated with the diffusion tensor images, showing a coefficient of determination (R2) value of 0.65 to 1.00. However, the images by the CTI method were less correlated with the diffusion tensor images and exhibited an averaged R2 value of 0.51. The CTI method could handle the effects of different ion concentrations as well as mobilities and extracellular volume fractions by collecting and processing additional B1 map data. It is necessary to select an application-specific model taking into account the pros and cons of each model. Future studies are essential to confirm the usefulness of these conductivity tensor imaging methods in clinical applications, such as tumor characterization, EEG source imaging, and treatment planning for electrical stimulation.

Objective: The objective of this study was to evaluate the clinical feasibility of high-resolution contrast-enhanced dynamic T1-weighted imaging (T1WI) using compressed sensing (CS) in magnetic resonance imaging., Methods: This study retrospectively included 35 patients who underwent dynamic T1WI using volumetric interpolated breath-hold examination (VIBE) with CS reconstruction (CS-VIBE) and 35 patients with conventional VIBE for comparison. Two observers assessed the liver and pancreas edges, hepatic artery, motion artifacts, and overall image quality. Quantitative analysis was performed by measuring signal intensity and image noise., Results: The results showed that CS-VIBE achieved significantly better anatomic delineation of the liver and pancreas edges and hepatic artery clarity than VIBE (P < 0.001). There were no significant differences in motion artifacts in dynamic phases and overall image quality. The signal intensities and INs of CS-VIBE were higher than VIBE., Conclusions: High-resolution dynamic T1WI using CS provides better anatomic delineation with comparable or better overall image quality than conventional VIBE., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Peritumoral edema (PE) of breast cancer at T2-weighted MR images is considered a poor prognostic sign and may represent the microenvironment surrounding the tumor; however, its histopathological mechanism remains unclear. The purpose of the study was to identify and describe detailed histopathological characteristics associated with PE at preoperative breast MRI in breast cancer patients. This retrospective study included breast cancer patients who had undergone preoperative MRI and surgery between January 2011 and December 2012. Two radiologists determined the presence of PE in consensus based on the signal intensity surrounding the tumor at T2-weighted images. The following detailed histopathological characteristics were reviewed by two breast pathologists using four-tiered grades; lymphovascular invasion, vessel ectasia, stromal fibrosis, growth pattern, and tumor budding. Tumor necrosis and tumor infiltrating lymphocytes were assessed using a percent scale. Baseline clinicopathological characteristics, including age and histologic grade, were collected. The associations between detailed histopathologic characteristics and PE were examined using multivariable logistic regression with odds ratio (OR) calculation. A total of 136 women (median age, 49 ± 9 years) were assessed; among them 34 (25.0%) had PE. After adjustment of baseline clinicopathological characteristics that were significantly associated with PE (age, T stage, N stage, histologic grade, and subtype, all Ps < 0.05), lymphovascular invasion (P = 0.009), vessel ectasia (P = 0.021), stromal fibrosis (P = 0.024), growth pattern (P = 0.036), and tumor necrosis (P < 0.001) were also associated with PE. In comparison with patients without PE, patients with PE were more likely to have a higher degree of lymphovascular invasion (OR, 2.9), vessel ectasia (OR, 3.3), stromal fibrosis (OR, 2.5), lesser degree of infiltrative growth pattern (OR, 0.4), and higher portion of tumor necrosis (OR, 1.4). PE of breast cancer at MRI is associated with detailed histopathological characteristics of lymphovascular invasion, vessel ectasia, stromal fibrosis, growth pattern, and tumor necrosis, suggesting a relevance for tumor microenvironment.

Neurogenic claudication is a typical manifestation of lumbar spinal stenosis (LSS). However, its pathophysiology is still unclear. The severity of clinical symptoms has been shown not to correlate with the degree of structural stenosis. Altered cerebrospinal fluid (CSF) flow has been suggested as one of the causative factors of LSS. The objectives of this study were to compare CSF dynamics at the lumbosacral level between patients with LSS and healthy controls and to investigate whether CSF dynamics parameters explain symptom severity in LSS. Phase-contrast magnetic resonance imaging (PC-MRI) was conducted to measure CSF dynamics in 18 healthy controls and 9 patients with LSS. Cephalic peak, caudal peak, and peak-to-peak CSF velocities were evaluated at the lumbosacral level in the patients and controls. The power of CSF dynamics parameters to predict symptom severity was determined using a linear regression analysis adjusted for demographic and structural variables. Significantly attenuated CSF flow velocity was observed in the patients compared with the controls. The cephalic peak, caudal peak, and peak-to-peak velocities at the lumbar level were greater in the controls than in the patients (p<0.001). The predictive power increased most when the peak-to-peak velocity was added (adjusted R2 = 0.410) to the model with age, body mass index, and the minimum anterior-posterior diameter (adjusted R2 = 0.306), and the peak-to-peak velocity was the only statistically significant variable. CSF dynamics variables showed an association with the severity of LSS symptoms, independent of structural stenosis. PC-MRI can help to further our understanding of the pathophysiology of neurogenic claudication and support the diagnosis of LSS., Competing Interests: The authors have declared that no competing interests exist.

Predicting amyloid positivity in patients with mild cognitive impairment (MCI) is crucial. In the present study, we predicted amyloid positivity with structural MRI using a radiomics approach. From MR images (including T1, T2 FLAIR, and DTI sequences) of 440 MCI patients, we extracted radiomics features composed of histogram and texture features. These features were used alone or in combination with baseline non-imaging predictors such as age, sex, and ApoE genotype to predict amyloid positivity. We used a regularized regression method for feature selection and prediction. The performance of the baseline non-imaging model was at a fair level (AUC = 0.71). Among single MR-sequence models, T1 and T2 FLAIR radiomics models also showed fair performances (AUC for test = 0.71-0.74, AUC for validation = 0.68-0.70) in predicting amyloid positivity. When T1 and T2 FLAIR radiomics features were combined, the AUC for test was 0.75 and AUC for validation was 0.72 (p vs. baseline model < 0.001). The model performed best when baseline features were combined with a T1 and T2 FLAIR radiomics model (AUC for test = 0.79, AUC for validation = 0.76), which was significantly better than those of the baseline model (p < 0.001) and the T1 + T2 FLAIR radiomics model (p < 0.001). In conclusion, radiomics features showed predictive value for amyloid positivity. It can be used in combination with other predictive features and possibly improve the prediction performance.

We used 3D printed-breast surgical guides (3DP-BSG) to designate the original tumor area from the pre-treatment magnetic resonance imaging (MRI) during breast-conserving surgery (BCS) in breast cancer patients who received neoadjuvant systemic therapy (NST). Targeting the original tumor area in such patients using conventional localization techniques is difficult. For precise BCS, a method that marks the tumor area found on MRI directly to the breast is needed. In this prospective study, patients were enrolled for BCS after receiving NST. Partial resection was performed using a prone/supine MRI-based 3DP-BSG. Frozen biopsies were analyzed to confirm clear tumor margins. The tumor characteristics, pathologic results, resection margins, and the distance between the tumor and margin were analyzed. Thirty-nine patients were enrolled with 3DP-BSG for BCS. The median nearest distance between the tumor and the resection margin was 3.9 cm (range 1.2-7.8 cm). Frozen sections showed positive margins in 4/39 (10.3%) patients. Three had invasive cancers, and one had carcinoma in situ; all underwent additional resection. Final pathology revealed clear margins. After 3-year surveillance, 3/39 patients had recurrent breast cancer. With 3DP-BSG for BCS in breast cancer patients receiving NST, the original tumor area can be identified and marked directly on the breast, which is useful for surgery. Trial Registration: Clinical Research Information Service (CRIS) Identifier Number: KCT0002272. First registration number and date: No. 1 (27/04/2016).

Background Achieving high-spatial-resolution pituitary MRI is challenging because of the trade-off between image noise and spatial resolution. Deep learning-based MRI reconstruction enables image denoising with sharp edges and reduced artifacts, which improves the image quality of thin-slice MRI. Purpose To assess the diagnostic performance of 1-mm slice thickness MRI with deep learning-based reconstruction (DLR) (hereafter, 1-mm MRI+DLR) compared with 3-mm slice thickness MRI (hereafter, 3-mm MRI) for identifying residual tumor and cavernous sinus invasion in the evaluation of postoperative pituitary adenoma. Materials and Methods This single-institution retrospective study included 65 patients (mean age ± standard deviation, 54 years ± 10; 26 women) who underwent a combined imaging protocol including 3-mm MRI and 1-mm MRI+DLR for postoperative evaluation of pituitary adenoma between August and October 2019. Reference standards for correct diagnosis were established by using all available imaging resources, clinical histories, laboratory findings, surgical records, and pathology reports. The diagnostic performances of 3-mm MRI, 1-mm slice thickness MRI without DLR (hereafter, 1-mm MRI), and 1-mm MRI+DLR for identifying residual tumor and cavernous sinus invasion were evaluated by two readers and compared between the protocols. Results The performance of 1-mm MRI+DLR in the identification of residual tumor was comparable to that of 3-mm MRI (area under the receiver operating characteristic curve [AUC], 0.89-0.92 vs 0.85-0.89, respectively; P ≥ .09). In the identification of cavernous sinus invasion, the diagnostic performance of 1-mm MRI+DLR was higher than that of 3-mm MRI (AUC, 0.95-0.98 vs 0.83-0.87, respectively; P ≤ .02). Conventional 1-mm MRI (AUC, 0.82-0.83) showed comparable diagnostic performance to 3-mm MRI (AUC, 0.83-0.87) ( P ≥ .38). With 1-mm MRI+DLR, residual tumor was diagnosed in 20 patients and cavernous sinus invasion was diagnosed in 14 patients, in whom these diagnoses were not made with 3-mm MRI. Conclusion In the postoperative evaluation of pituitary adenoma, 1-mm slice thickness MRI with deep learning-based reconstruction showed higher diagnostic performance than 3-mm slice thickness MRI in the identification of cavernous sinus invasion and comparable diagnostic performance to 3-mm slice thickness MRI in the identification of residual tumor. © RSNA, 2020 Online supplemental material is available for this article.

To investigative whether radiomics features in bilateral hippocampi from MRI can identify temporal lobe epilepsy (TLE). A total of 131 subjects with MRI (66 TLE patients [35 right and 31 left TLE] and 65 healthy controls [HC]) were allocated to training (n = 90) and test (n = 41) sets. Radiomics features (n = 186) from the bilateral hippocampi were extracted from T1-weighted images. After feature selection, machine learning models were trained. The performance of the classifier was validated in the test set to differentiate TLE from HC and ipsilateral TLE from HC. Identical processes were performed to differentiate right TLE from HC (training set, n = 69; test set; n = 31) and left TLE from HC (training set, n = 66; test set, n = 30). The best-performing model for identifying TLE showed an AUC, accuracy, sensitivity, and specificity of 0.848, 84.8%, 76.2%, and 75.0% in the test set, respectively. The best-performing radiomics models for identifying right TLE and left TLE subgroups showed AUCs of 0.845 and 0.840 in the test set, respectively. In addition, multiple radiomics features significantly correlated with neuropsychological test scores (false discovery rate-corrected p-values < 0.05). The radiomics model from hippocampus can be a potential biomarker for identifying TLE.

Identification of predictive neuroimaging markers of pain intensity changes is a crucial issue to better understand macroscopic neural mechanisms of pain. Although a single connection between the medial prefrontal cortex and nucleus accumbens has been suggested as a powerful marker, how the complex interactions on a large-scale brain network can serve as the markers is underexplored. Here, we aimed to identify a set of functional connections predictive of longitudinal changes in pain intensity using large-scale brain networks. We re-analyzed previously published resting-state functional magnetic resonance imaging data of 49 subacute back pain (SBP) patients. We built a network-level model that predicts changes in pain intensity over one year by combining independent component analysis and a penalized regression framework. Connections involving top-down pain modulation, multisensory integration, and mesocorticolimbic circuits were identified as predictive markers for pain intensity changes. Pearson's correlations between actual and predicted pain scores were r = 0.33-0.72, and group classification results between SBP patients with persisting pain and recovering patients, in terms of area under the curve (AUC), were 0.89/0.75/0.75 for visits four/three/two, thus outperforming the previous work (AUC 0.83/0.73/0.67). This study identified functional connections important for longitudinal changes in pain intensity in SBP patients, providing provisional markers to predict future pain using large-scale brain networks.

Purpose: We purposed to compare diagnostic accuracy of contrast-enhanced (CE) 3D T1-weighted fast field echo (3D T1-WI), CE 2D spin echo T1-weighted image (2D T1-WI), and CE 2D T2 FLAIR on evaluation of leptomeningeal metastasis(LM) using detailed features suggested in RANO proposal in a homogeneous group with cytology-proven LM., Methods: Thirty-five lung adenocarcinoma patients with CSF cytology-proven leptomeningeal metastasis were enrolled in this retrospective analysis, who were enrolled in the prospective study (NCT03257124). MR images including CE 3D T1-WI, CE 2D T1-WI, and CE 2D FLAIR were reviewed. Presence of leptomeningeal nodule, leptomeningeal enhancement, and cranial nerve enhancement was evaluated according to the RANO proposal. Diagnostic accuracy of each sequence was compared and added value of CE 2D FLAIR to CE 3D T1-WI was evaluated., Results: Two patients had unmeasurable small nodules recognized on 3D T1-WI only. Leptomeningeal enhancement was positive in 60%, 60%, and 77.1%, cranial nerve enhancement was positive in 51.4%, 45.7%, and 68.6% of the patients on 3D T1-WI, 2D T1-WI, and 2D FLAIR, respectively. Overall sensitivity for detection of LM was 71.4%, 71.4%, and 82.9% on 3D T1-WI, 2D T1-WI, and 2D FLAIR. When adding 2D FLAIR to 3D T1-WI, overall sensitivity for detection of LM was 82.9%., Conclusion: 3D T1-WI is the best for identifying leptomeningeal nodules. The sensitivity of 2D FLAIR is the highest for both LNE and CNE. Since both sequences are complementary, it can be helpful to take both sequences. Checking each feature according to the RANO proposal, especially CNE, may help you not to miss LM.

Objective: To determine the association of meniscal flounce with the pattern and location of the meniscal tear, concomitant ligamentous injury, amount of knee joint effusion, and flexion and rotation angles., Materials and Methods: A total of 283 knees of 280 patients were retrospectively reviewed over a 9-month period. Thirty-one magnetic resonance images of patients with meniscal flounce were compared with those of age- and sex-matched control group (n = 62) without meniscal flounce. The presence of meniscal tear was evaluated and, if present, its location and pattern were recorded. The amount of joint effusion was graded, and the joint angle was measured. The Fisher's exact, Cochran-Armitage trend, and t tests were performed to compare the findings between the two groups. The decision tree analysis was employed to determine the most significant factor of meniscal flounce., Results: Meniscal flounce was present in 11.0% (31/283) of the adult population. Approximately 80.6% of meniscal flounce occurred in the torn medial menisci. The presence of meniscal flounce was significantly associated with tears at the body (p = 0.007), posterior horn (p = 0.001), and meniscocapsular junction (p = 0.002) of the medial meniscus. The decision tree analysis revealed that the posterior horn tear of the medial meniscus was the most significant predictor of meniscal flounce., Conclusion: The most significant factor associated with meniscal flounce is tear at the posterior horn of the medial meniscus, followed by tear at the meniscocapsular junction.

Background: MRI exams for patients with MR-conditional active implantable medical devices (AIMDs) are contraindicated unless specific conditions are met. This limits the maximum specific absorption rate (SAR, W/kg). Currently, there is no general framework to guide meeting a lower SAR limit., Purpose: To design and evaluate a workflow for modifying MRI protocols to whole-body SAR (WB-SAR ≤0.1 W/kg) and local-head SAR (LH-SAR ≤0.3 W/kg) limits while mitigating the impact on image quality and exam time., Study Type: Prospective., Population: Twenty healthy volunteers on head (n = 5), C-spine (n = 5), T-spine (n = 5), and L-spine (n = 5) with IRB consent., Assessment: Vendor-provided head, C-spine, T-spine, and L-spine protocols (SAR RT ) were modified to meet both low SAR targets (SAR LOW ) using the proposed workflow. in vitro SNR and CNR were evaluated with a T 1 -T 2 phantom. in vivo image quality and clinical acceptability were scored using a 5-point Likert scale for two blinded readers., Field Strength/sequences: 1.5T/spin-echoes, gradient-echoes., Statistical Analysis: In vitro SNR and CNR values were evaluated with a repeated measures general linear model. in vivo image quality and clinical acceptability were evaluated using a generalized estimating equation analysis (GEE). The two reader's level of agreement was analyzed using Cohen's kappa statistical analysis., Results: Using the workflow, SAR limits were met., Lh-Sar: 0.12 ± 0.02 W/kg, median (SD) values for LH-SAR were 0.12 (0.02) W/kg and WB-SAR: 0.09 (0.01) W/kg. Examination time did not increase ≤2x the initial time. SAR RT SNR values were higher and significantly different than SAR LOW (P < 0.05). However, no significant difference was observed between the CNR values (value = 0.21). Median (IQR) CNR values were 14.2 (25.0) vs. 15.1 (9.2) for head, 12.1 (16.9) vs. 25.3 (14.2) for C-spine, 81.6 (70.1) vs. 71.0 (26.6) for T-spine, and 51.4 (52.6) vs. 37.7 (27.3) for L-spine. Image quality scores were not significantly different between SAR RT and SAR LOW (median [SD] scores were 4.0 [0.01] vs. 4.3 [0.2], P > 0.05)., Data Conclusion: The proposed workflow provides guidance for modifying routine MRI exams to achieve low SAR limits. This can benefit patients referred for an MRI exam with low SAR MR-conditional AIMDs., Level of Evidence: 1 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;52:91-102., (© 2020 International Society for Magnetic Resonance in Medicine.)

Introduction: To compare diagnostic performance of additional two-dimensional (2D) oblique coronal view and three-dimensional (3D) T2-weighted fast spin-echo(FSE) images for diagnosing injury of the anterior inferior tibiofibular (AiTFL) and anterior talofibular ligaments (ATFL)., Methods: This study included 48 patients with ankle sprain who had undergone MRI using standard protocol and two additional sequences with 2D oblique coronal and 3D isotropic images, followed by arthroscopic surgery. Ligament injuries was subdivided by intact tendon, partial or complete tear. Retrospectively, two musculoskeletal radiologists respectively reviewed three image sets of MR including 2D axial image only (set 1), 2D axial and oblique coronal images (set 2), and 2D axial with 3D-isotropic images (set 3). Using arthroscopic findings as reference standard, diagnostic performances of both methods were analysed by the area under the curve (AUC)., Results: Arthroscopy confirmed 13 AiTFL and 41 ATFL injuries. For AiTFL, when set 1 and set 3 were compared, AUC value was significantly higher for set 3 (P < 0.05). However, there was no significant difference between AUC values for set 2 and set 3 sequences by either reader for either type of tear (P > 0.05). For ATFL, both readers found there was no significant difference in AUC values between set 1 and set 3 and between set 2 and set 3., Conclusion: Additional oblique coronal sequence demonstrated better diagnostic performance for AiTFL injury than conventional and isotropic imaging did. This sequence showed as much diagnostic accuracy as isotropic sequence for evaluation of ATFL injury., (© 2020 The Royal Australian and New Zealand College of Radiologists.)

Background: Electrical conductivity of a biological tissue at low frequencies can be approximately expressed as a tensor. Noting that cross-sectional imaging of a low-frequency conductivity tensor distribution inside the human body has wide clinical applications of many bioelectromagnetic phenomena, a new conductivity tensor imaging (CTI) technique has been lately developed using an MRI scanner. Since the technique is based on a few assumptions between mobility and diffusivity of ions and water molecules, experimental validations are needed before applying it to clinical studies., Methods: We designed two conductivity phantoms each with three compartments. The compartments were filled with electrolytes and/or giant vesicle suspensions. The giant vesicles were cell-like materials with thin insulating membranes. We controlled viscosity of the electrolytes and the giant vesicle suspensions to change ion mobility and therefore conductivity values. The conductivity values of the electrolytes and giant vesicle suspensions were measured using an impedance analyzer before CTI experiments. A 9.4-T research MRI scanner was used to reconstruct conductivity tensor images of the phantoms., Results: The CTI technique successfully reconstructed conductivity tensor images of the phantoms with a voxel size of [Formula: see text]. The relative [Formula: see text] errors between the conductivity values measured by the impedance analyzer and those reconstructed by the MRI scanner was between 1.1 and 11.5., Conclusions: The accuracy of the new CTI technique was estimated to be high enough for most clinical applications. Future studies of animal models and human subjects should be pursued to show the clinical efficacy of the CTI technique.

Background After publication of the findings of the American College of Surgeons Oncology Group Z1071 trial, sentinel lymph node biopsy (SLNB) has been increasingly performed in patients with breast cancer after neoadjuvant chemotherapy (NAC). Purpose To investigate the pretreatment breast MRI and clinical-pathologic characteristics associated with failed sentinel node identification after NAC in patients with breast cancer. Materials and Methods Patients who underwent SLNB after NAC between January 2015 and January 2019 were retrospectively identified. Two radiologists independently reviewed the characteristics of axillary nodes (number, perinodal infiltration, cortical thickness, and maximal diameter) at pretreatment breast MRI. The associations of the clinical-pathologic and imaging characteristics of the axillary nodes with sentinel node identification were assessed by using the χ 2 test and/or the χ 2 test for trend and multivariable logistic regression with odds ratio (OR) calculation. Results A total of 276 women (mean age ± standard deviation, 48 years ± 9; range, 27-68 years) were included. Sentinel nodes were identified in 252 of the 276 patients (91%). Multivariable analysis showed that higher (stage 3 or 4) clinical T stages (OR = 5.2, P = .004 for radiologist 1; OR = 4.6, P = .01 for radiologist 2), use of a single tracer (OR = 4.3, P = .04 for radiologist 1; OR = 3.9, P = .046 for radiologist 2), a greater number (10 or more) of suspicious axillary nodes (OR = 11.5, P = .002 for radiologist 1; OR = 8.3, P = .01 for radiologist 2), and the presence of perinodal infiltration (OR = 7.0, P = .002 for radiologist 1; OR = 7.5, P = .003 for radiologist 2) were associated with failed sentinel node identification. Conclusion A greater number of suspicious axillary nodes and the presence of perinodal infiltration at pretreatment MRI, higher clinical T stages, and use of a single tracer were independently associated with failed sentinel node identification after neoadjuvant chemotherapy in patients with breast cancer. © RSNA, 2020 See also the editorial by Imbriaco in this issue.

Ménière's Disease (MD) is difficult to diagnose and evaluate objectively over the course of treatment. Recently, several studies have reported MD diagnoses by MRI-based endolymphatic hydrops (EH) analysis. However, this method is time-consuming and complicated. Therefore, a fast, objective, and accurate evaluation tool is necessary. The purpose of this study was to develop an algorithm that can accurately analyze EH on intravenous (IV) gadolinium (Gd)-enhanced inner-ear MRI using artificial intelligence (AI) with deep learning. In this study, we developed a convolutional neural network (CNN)-based deep-learning model named INHEARIT (INner ear Hydrops Estimation via ARtificial InTelligence) for the automatic segmentation of the cochlea and vestibule, and calculation of the EH ratio in the segmented region. Measurement of the EH ratio was performed manually by a neuro-otologist and neuro-radiologist and by estimation with the INHEARIT model and were highly consistent (intraclass correlation coefficient = 0.971). This is the first study to demonstrate that automated EH ratio measurements are possible, which is important in the current clinical context where the usefulness of IV-Gd inner-ear MRI for MD diagnosis is increasing.

Objectives: To determine the diagnostic accuracy of magnetic resonance tumor regression grade (mrTRG) for pathological complete response (pCR) and its correlation with pathological findings., Methods: Original studies that investigated the correlation of mrTRG with pathological tumor regression grade and pathological T stage were identified in MEDLINE and EMBASE up until August 31, 2018, according to PRISMA guidelines. The search terms included colorectal cancer, chemoradiation therapy, magnetic resonance imaging, and response or regression. Meta-analytic summary sensitivity and specificity for pathologic complete response (pCR) and pathologic T1 or lower than T1 stage (≤ypT1) were calculated using a bivariate random-effects model. The sensitivity and specificity were calculated in both mrTRG 1 and mrTRG 1 or 2, respectively., Results: Six studies with 916 patients were included. The meta-analytic summary sensitivity and specificity of mrTRG 1 for pCR were 32.3% (95% CI, 18.2-50.6%) and 93.5% (95% CI, 91.5-95.1%), while for ≤ypT1 they were 31.8% (95% CI, 16.2-53.0%) and 94.7% (95% CI, 91.9-96.5%). On the contrary, sensitivity and specificity of mrTRG 1 or 2 for pCR were 69.9% (95% CI, 60.2-78.1%) and 62.2% (95% CI, 56.2-67.8%), while those for ≤ypT1 were 71.4% (95% CI, 61.6-79.6%) and 67.7% (95% CI, 59.8-74.7%)., Conclusions: mrTRG 1 showed high specificity for pCR and ≤ypT1, but suboptimal sensitivity. mrTRG 1 or 2 showed higher sensitivity for pCR and ≤ypT1, but lower specificity. Because of the suboptimal sensitivity of mrTRG 1, it might be limited as a criterion for less aggressive treatment after neoadjuvant chemoradiotherapy., Key Points: • Magnetic resonance tumor regression grade 1 shows high specificity for pCR and ≤ypT1, but suboptimal sensitivity. • Magnetic resonance tumor regression grade 1 or 2 shows higher sensitivity for pCR and ≤ypT1, but lower specificity than magnetic resonance tumor regression grade 1 alone.

This study investigated distinct neuroimaging features measured by cortical thickness and subcortical structural shape abnormality in early-onset (EO, onset age <65 years) and late-onset (LO, onset age ≥65 years) nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA) patients. Cortical thickness and subcortical structural shape analyses were performed using a surface-based method from 38 patients with nfvPPA and 76 cognitively normal individuals. To minimize the effects of physiological aging, we used W-scores in comparisons between the groups. The EO-nfvPPA group exhibited more extensive cortical thickness reductions predominantly in the left perisylvian, lateral and medial prefrontal, temporal, posterior cingulate, and precuneus regions than the LO-nfvPPA group. The EO-nfvPPA group also exhibited significantly greater subcortical structural shape abnormality than the LO-nfvPPA group, mainly in the left striatum, hippocampus, and amygdala. Our findings suggested that there were differences in neuroimaging features between these groups by the age of symptom onset, which might be explained by underlying heterogeneous neuropathological differences or the age-related brain reserve hypothesis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: Acute ischemic stroke is one of the primary causes of death worldwide. Recent studies have shown that the assessment of collateral status could aid in improving the treatment for patients with acute ischemic stroke. We present a 3D deep regression neural network to automatically generate the collateral images from dynamic susceptibility contrast-enhanced magnetic resonance perfusion (DSC-MRP) in acute ischemic stroke., Methods: This retrospective study includes 144 subjects with acute ischemic stroke (stroke cases) and 201 subjects without acute ischemic stroke (controls). DSC-MRP images of these subjects were manually inspected for collateral assessment in arterial, capillary, early and late venous, and delay phases. The proposed network was trained on 205 subjects, and the optimal model was chosen using the validation set of 64 subjects. The predictive power of the network was assessed on the test set of 76 subjects using the squared correlation coefficient (R-squared), mean absolute error (MAE), Tanimoto measure (TM), and structural similarity index (SSIM)., Results: The proposed network was able to predict the five phase maps with high accuracy. On average, 0.897 R-squared, 0.581 × 10 -1 MAE, 0.946 TM, and 0.846 SSIM were achieved for the five phase maps. No statistically significant difference was, in general, found between controls and stroke cases. The performance of the proposed network was lower in the arterial and venous phases than the other three phases., Conclusion: The results suggested that the proposed network performs equally well for both control and acute ischemic stroke groups. The proposed network could help automate the assessment of collateral status in an efficient and effective manner and improve the quality and yield of diagnosis of acute ischemic stroke. The follow-up study will entail the clinical evaluation of the collateral images that are generated by the proposed network.

Radiation therapy (RT) has been widely used as a powerful treatment tool to address cancerous tissues because of its ability to control cell growth. Its ionizing radiation damages the DNA of cancerous tissues, leading to cell death. Medical imaging, however, still has limitations regarding the reliability of its assessment of tissue response and in predicting the treatment effect because of its inability to provide contrast information on the gradual, minute tissue changes after RT. A recently developed magnetic resonance (MR)-based conductivity imaging method may provide direct, highly sensitive information on this tissue response because its contrast mechanism is based on the concentration and mobility of ions in intracellular and extracellular spaces. In this feasibility study, we applied T2-weighted, diffusion-weighted, and electrical conductivity imaging to mouse brain, thus, using the MR imaging to map the tissue response after radiation exposure. To evaluate the degree of response, we measured the T2 relaxation, apparent diffusion coefficient (ADC), and electrical conductivity of brain tissues before and after irradiation. The conductivity images, which showed significantly higher sensitivity than other MR imaging methods, indicated that the contrast is distinguishable in different ways at different areas of the brain. Future studies will focus on verifying these results and the long-term evaluation of conductivity changes using various irradiation methods for clinical applications.

We aimed to evaluate the effect of 5 alpha-reductase inhibitor (5-ARI) treatment on prostate cancer (PCa) and clinically significant PCa (csPCa) detection in patients undergoing transrectal ultrasound (TRUS)/magnetic resonance imaging (MRI) fusion biopsy in the current era of multi-parametric MRI (mpMRI). We retrospectively reviewed our TRUS/MRI fusion biopsy database (n = 706). Eighty (11.3%) patients who had used 5-ARI for more than one year at the time of biopsy were stratified as 5-ARI group. Subsequently, we performed comparative analyses of 5-ARI and non-5-ARI groups. csPCa was defined by a Gleason score ≥3 + 4 in a single biopsy core. Chi-squared test was used to evaluate the performance of mpMRI in predicting PCa/csPCa between the two groups. Multivariate logistic regression analyses were performed to evaluate the significant variables associated with PCa detection. There were no significant differences in PCa/csPCa detection rates between 5-ARI and non-5-ARI groups (all, P > 0.05). In multivariate logistic regression analyses for the evaluation of variables associated with csPCa detection, age (odds ratio [OR], 1.062; 95% confidence interval [CI], 1.035-1.090; P < 0.001), pre-biopsy PSA (OR, 1.062; 95% CI, 1.034-1.090; P < 0.001), prostate volume on TRUS (OR, 0.956; 95% CI, 0.943-0.970, P < 0.001), and PI-RADsV2 category (OR, 5.528; 95% CI, 3.017-10.131; P < 0.001) were found to be significant predictors. However, 5-ARI had no significant association with PCa detection (P = 0.384). Conclusively, 5-ARI therapy did not adversely affect PCa/csPCa detection after TRUS/MRI fusion biopsy, which suggests that exposure to 5-ARI may not impair the performance of mpMRI.

Purpose: This study aimed to elucidate the primary differences in trochlear morphology between men and women utilizing three-dimensional magnetic resonance image reconstruction of the femoral trochlea., Methods: Differences in anthropometric femoral trochlea data of 975 patients (825 women, 150 men) were evaluated. The following morphological parameters were measured at three flexion angles (15°, 30°, and 45°) of the femoral trochlea: the sulcus angle, condylar height, and the trochlear groove orientation and mediolateral groove position., Results: The sulcus angle was significantly greater in women than in men at 15° and 45° flexions (P < 0.05). However, there was no gender difference found in the sulcus angle at 30° flexion. Medial and lateral condylar height values were greater in men than in women for the three flexion angles (P < 0.01). The trochlear groove orientation and mediolateral groove position showed no gender-related differences., Conclusions: Magnetic resonance image reconstruction demonstrated that measurement of trochlear morphology varied significantly between men and women. This study provides guidelines for the design of a suitable femoral component for total knee arthroplasty, considering gender-specific differences in the Korean population. Biomechanical guidelines for total knee arthroplasty in Korean individuals can be optimized using our finding, so as the risk of patellar dislocation to be decreased. Surgeons should be aware of gender differences in femoral trochlear to optimize choice of implant., Level of Evidence: III.

Background: Electrical conductivity-based magnetic resonance (MR) imaging may provide unique information on tissue condition because its contrast originates from the concentration and mobility of ions in the cellular space. We imaged the conductivity of normal canine prostate in vivo and evaluated tissue contrast in terms of both the conductivity distribution and anatomical significance., Methods: Five healthy laboratory beagles were used. After clipping the pelvis hair, we attached electrodes and placed each dog inside the bore of an MRI scanner. During MR scanning, we injected imaging currents into two mutually orthogonal directions between two pairs of electrodes. A multi spin echo pulse sequence was used to obtain the MR magnitude and magnetic flux density images. The projected current density algorithm was used to reconstruct the conductivity image., Results: Conductivity images showed unique contrast depending on the prostatic tissues. From the conductivity distribution, conductivity was highest in the center area and lower in the order of the middle and outer areas of prostatic tissues. The middle and outer areas were, respectively, 11.2 and 25.5% lower than the center area. Considering anatomical significance, conductivity was highest in the central zone and lower in the order of the transitional and peripheral zones in all prostates. The transitional and peripheral zones were, respectively, 7.5 and 17.8% lower than the central zone., Conclusions: Current conductivity-based MR imaging can differentiate prostatic tissues without using any contrast media or additional MR scans. The electrical conductivity images with unique contrast to tissue condition can provide a prior information on tissues in situ to be used for human imaging.