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Intramuscular administration is a commonly used method for delivering sedatives and anesthetics in veterinary medicine. Previous studies have reported inflammation at the intramuscular injection site in laboratory animals and observed signal changes on MRI following intramuscular injections in humans. We hypothesized that following intramuscular injection, the site would exhibit T2 hyperintensity and contrast enhancement on MRI. To investigate this, this prospective study evaluated the pattern of signal changes and grade of T2 signal intensity and contrast enhancement over time after the intramuscular injection of medetomidine at a premedication dosage, comparing it to saline. MRI scans were performed immediately postinjection into the biceps femoris and quadriceps femoris muscles, as well as at 2, 8, 24, and 72 h, and 7 days postinjection. A semiquantitative scale was utilized to grade signal intensity and contrast enhancement. Both medetomidine and saline injections showed T2 hyperintensity immediately after injection and contrast enhancement from 2 h postinjection, manifesting as flame-shaped. These signal changes decreased up to 24 h postinjection (p < .05). The signal changes induced by medetomidine showed higher T2 hyperintense change and stronger contrast enhancement compared with saline at most time points, with the signal changes persisting for a longer duration (p < .05). These findings suggest that intramuscular administration of medetomidine induces a more severe tissue reaction compared with saline, and the results are expected to aid in the differentiation of various muscle diseases that present with similar MRI findings., (© 2024 American College of Veterinary Radiology.)

To ensure maximum therapeutic safety and efficacy of stem cell transplantation, it is essential to observe the kinetics of behavior, accumulation, and engraftment of transplanted stem cells in vivo. However, it is difficult to detect transplanted stem cells with high sensitivity by conventional in vivo imaging technologies. To diagnose the kinetics of transplanted stem cells, we prepared multifunctional nanoparticles, Gd 2 O 3 co-doped with Er 3+ and Yb 3+ (Gd 2 O 3 : Er, Yb-NPs), and developed an in vivo double modal imaging technique with near-infrared-II (NIR-II) fluorescence imaging and magnetic resonance imaging (MRI) of stem cells using Gd 2 O 3 : Er, Yb-NPs. Gd 2 O 3 : Er, Yb-NPs were transduced into adipose tissue-derived stem cells (ASCs) through a simple incubation process without cytotoxicity under certain concentrations of Gd 2 O 3 : Er, Yb-NPs and were found not to affect the morphology of ASCs. ASCs labeled with Gd 2 O 3 : Er, Yb-NPs were transplanted subcutaneously onto the backs of mice, and successfully imaged with good contrast using an in vivo NIR-II fluorescence imaging and MRI system. These data suggest that Gd 2 O 3 : Er, Yb-NPs may be useful for in vivo double modal imaging with NIR-II fluorescence imaging and MRI of transplanted stem cells., (© 2024. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Background: We aimed to develop an artificial intelligence (AI) algorithm that predicts the volume and location of clinically significant cancer (CSCa) using convolutional neural network (CNN) trained with integration of multiparametric MR-US image data and MRI-US fusion prostate biopsy (MRI-US PBx) trajectory-proven pathology data., Methods: Twenty consecutive patients prospectively underwent MRI-US PBx, followed by robot-assisted radical prostatectomy (RARP). The AI algorithm was trained with the integration of MR-US image data with a MRI-US PBx trajectory-proven pathology. The relationship with the 3D-cancer-mapping of RARP specimens was compared between AI system-suggested 3D-CSCa mapping and an experienced radiologist's suggested 3D-CSCa mapping on MRI alone according to the Prostate Imaging Reporting and Data System (PI-RADS) version 2. The characteristics of detected and undetected tumors at AI were compared in 22,968 image data. The relationships between CSCa volumes and volumes predicted by AI as well as the radiologist's reading based on PI-RADS were analyzed., Results: The concordance of the CSCa center with that in RARP specimens was significantly higher in the AI prediction than the radiologist' reading (83% vs. 54%, p = 0.036). CSCa volumes predicted with AI were more accurate (r = 0.90, p < 0.001) than the radiologist's reading. The limitations include that the elastic fusion technology has its own registration error., Conclusions: We presented a novel pilot AI algorithm for 3D prediction of PCa. AI was trained by integration of multiparametric MR-US image data and fusion biopsy trajectory-proven pathology data. This deep learning AI model may more precisely predict the 3D mapping of CSCa in its volume and center location than a radiologist's reading based on PI-RADS version 2, and has potential in the planning of focal therapy., (© 2022 Wiley Periodicals LLC.)

Background: Biventricular physiological interaction remains a challenging problem in cardiology. We developed a four-dimensional (4D) flow magnetic resonance imaging (MRI) scan and clinically available analysis protocol based on beat tracking of the cardiovascular lumen without contrast medium, which enabled measurement of the biventricular hemodynamics and energetic performance by calculating flow energy loss (EL) and kinetic energy (KE). The aim of this study was to observe the flow patterns and energy dynamics to reveal the physiology of the right and left ventricular systems., Methods: 4D flow MRI studies were performed in 19 healthy volunteers including 11 male and 8 female. The right and left ventricular systems were segmented to visualize the flow patterns and to quantify the hemodynamics and energy dynamics., Results: A large vortex was observed in the left ventricle (LV), along the longitudinal axis, during end diastole and early systole. At early systole, the vortex appeared to facilitate smooth ejection with little EL. In contrast, in the right ventricle (RV), there were vortices near the free wall in both the short and long axes during the diastolic filling phase. Mean EL index during a single cardiac cycle in the right and left heart systems was 0.63 ± 0.16 (0.42-0.99) mW/m 2 , and 1.02 ± 0.26 (0.58-1.58) mW/m 2 , respectively. EL is inevitable loss caused by the vortex flow to facilitate smooth right and left ventricular function and left-sided EL tended to correlate positively with heart rate and right ventricular stroke volume. Kinetic energy at the aortic valve was influenced by LV end-diastolic volume/stroke volume. No gender difference was observed., Conclusions: The RV appears to function as a regulator of the energy dynamics of the LV system., (Copyright © 2021. Published by Elsevier Ltd.)

Objective: This study aimed to quantify chronological cerebral blood flow (CBF) changes using arterial spin labeling (ASL) magnetic resonance imaging in patients with reversible cerebral vasoconstriction syndrome (RCVS)., Background: Quantitative ASL analyses in RCVS have not been well described in the literature., Methods: Quantification of ASL using an automated region-of-interest placement software and a 5-point visual scale of vasoconstriction severity was performed in five RCVS patients. The association between CBF changes and RCVS-related complications was evaluated., Results: Quantitative ASL revealed variable patterns of decreasing CBF in the first week, followed by subsequent increases. Notably, arterial vasoconstriction paradoxically progressed despite an increase in CBF from the first to the second week; this increase was relatively higher in patients with both cortical subarachnoid hemorrhage and posterior reversible encephalopathy syndrome., Conclusions: Quantitative ASL revealed that CBF initially decreased and subsequently increased, especially in the second week. These changes may serve as surrogate imaging markers for RCVS-related complications, and could further contribute to understanding the pathology of RCVS., (© 2021 American Headache Society.)

Background: Pathological complete response (pCR) is often achieved by neoadjuvant chemotherapy (NAC), particularly in hormone receptor-negative breast cancer. Contrast-enhanced magnetic resonance imaging (cMRI) is the most reliable imaging modality to evaluate the pathological effect of NAC. Ultrasonography is indispensable to collect representative specimens from the target lesion by core needle biopsy (CNB). This study aimed to evaluate the accuracy of predicting pCR by adding CNB after NAC, in cases with complete clinical response (cCR) diagnosed by cMRI., Methods: In this prospective multicentre study, we evaluated patients diagnosed with cCR by cMRI after NAC. Ultrasound-guided CNB (uCNB) using a 14G needle was performed without clip markers under general anaesthesia as planned surgery. Specimens collected by uCNB were compared to those resected surgically and were categorized as (i) no carcinoma (ypT0), (ii) no invasive carcinoma and only residual carcinoma in situ (ypTis) and (iii) residual invasive carcinoma. The concordance of pathological results between the uCNB and surgical specimens was evaluated., Results: Of the 83 patients evaluated, 41 (49.4%) and 17 (20.5%) of them had ypT0 and ypTis, respectively. The false negative rates (FNR), sensitivity and specificity for predicting ypT0 by uCNB were 50.0%, 50.0%, 100%, respectively, and those for predicting ypT0+ypTis were 28.0%, 72.0% and 98.3%, respectively. The concordance rates were 74.7% (62/83) for ypT0 and 90.4% (75/83) for ypT0+ypTis., Conclusion: In cCR cases diagnosed by cMRI, uCNB was not accurate enough to predict pCR. Additional modalities like clip placements and/or thicker core needles may be required for better prediction., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: This study aimed to develop a deep convolutional neural network (CNN)-based dose distribution conversion approach for the correction of the influence of a magnetic field for online MR-guided adaptive radiotherapy., Methods: Our model is based on DenseNet and consists of two 2D input channels and one 2D output channel. These three types of data comprise dose distributions without a magnetic field (uncorrected), electron density (ED) maps, and dose distributions with a magnetic field. These data were generated as follows: both types of dose distributions were created using 15-field IMRT in the same conditions except for the presence or absence of a magnetic field with the GPU Monte Carlo dose in Monaco version 5.4; ED maps were acquired with planning CT images using a clinical CT-to-ED table at our institution. Data for 50 prostate cancer patients were used; 30 patients were allocated for training, 10 for validation, and 10 for testing using 4-fold cross-validation based on rectum gas volume. The accuracy of the model was evaluated by comparing 2D gamma-indexes against the dose distributions in each irradiation field with a magnetic field (true)., Results: The gamma indexes in the body for CNN-corrected uncorrected dose against the true dose were 94.95% ± 4.69% and 63.19% ± 3.63%, respectively. The gamma indexes with 2%/2-mm criteria were improved by 10% in most test cases (99.36%)., Conclusions: Our results suggest that the CNN-based approach can be used to correct the dose-distribution influences with a magnetic field in prostate cancer treatment., (Copyright © 2020 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

This short report clarifies the heterogeneity of structural magnetic resonance imaging (MRI) findings in seven demented patients due to pathologically accumulated TAR DNA-binding protein-43 (TDP-43) protein using visual analyses including visual rating scales (i.e., global cortical atrophy and medial temporal atrophy scales). In addition to the well-known frontotemporal lobar atrophy, structural MRI has revealed multifaceted imaging findings including asymmetric atrophy of the frontoparietal lobe and cerebral peduncle, midbrain atrophy, and localized or diffuse white matter T2 hyperintensity. Understanding of these multifaceted neuroimaging findings is important for the precise antemortem diagnosis of TDP-43 proteinopathy.

Elongated axial length of the eye increases the morbidity of glaucoma. Myopia also associates with elongated axial length, and such ellipsoid shape of the eyeball strongly contributes its pathogenesis. Morphological features of the eyeballs, which could be important factors for developing glaucoma, have not been well described. The aim of this study was to investigate the three-dimensional (3D) topographic features of glaucomatous eyeballs with/without myopia to evaluate the potential of those features for predicting glaucoma. Using a 3.0-tesla MRI, volume-isotropic turbo-spin-echo acquisition T2-weighted images were obtained from 55 patients with glaucoma and 22 controls to delineate the eyeballs. Eyeball volumes, axial lengths and transverse lengths were semi-automatically calculated and compared between four groups: normal, myopia, glaucoma, and glaucoma with myopia. Both glaucoma and myopia increased the eyeball volume compared to the normal eyes. An increased anisotropy ratio (axial/transversus length) was observed in myopic eyes compared to normal, whereas in the glaucomatous eyes, with or without myopia, no increase in anisotropy ratio was observed. Increasing volume of eyes can be caused by myopia and glaucoma. Myopic eyes were ellipsoid in shape, but there was less anisotropy and a near-spherical shape in glaucomatous eyes, even in glaucomatous myopic eyes.

Purpose: To investigate whether whole-tumor histogram analyses of diffusivity measurements derived from q-space imaging (QSI) improves the differentiation between meningioma and schwannoma., Materials and Methods: Fifteen extra-axial tumors (11 meningiomas and 4 schwannomas) with MR examinations from April 2011 to May 2013 were included. Three-dimensional regions of interest (ROI) encompassed the whole tumor, including cystic areas. Histogram analyses of mean displacement (MD) derived from QSI and apparent diffusion coefficient (ADC) for the ROI were performed at mean, the five percentiles of MD n and ADC n (n = 5, 25, 50, 75, 95th), kurtosis, and skewness. To determine the diagnostic ability of MD n and ADC n , we also compared the area under the curve (AUC) on receiver operating characteristic (ROC) analysis., Results: Histogram analyses revealed significant differences between meningioma and schwannoma in MD 75 , ADC 25 , ADC 50 , ADC 75 , and kurtosis of ADC. The ROC analysis of kurtosis of ADC and MD 75 resulted in an AUC of 1.0 and 0.96, respectively. There were no significant differences between the AUC of MD 75 and that of kurtosis of ADC (p = 0.41)., Conclusion: The histogram analyses of MD and ADC derived from QSI were both equally useful in differentiating between intracranial meningioma and schwannoma.

Dynamic contrast-enhanced MRI may yield variable longitudinal-relaxation time (T1) values depending on the precision of the fat-suppression (FS) technique. This study aimed to investigate the influences of FS methods on T1 value measurements on phantoms containing test tubes filled with mixtures of five volumes of fat, six amounts of contrast agent, and water. Volumetric interpolated images were obtained using several FS methods and flip angles. T1 maps were created based on the variable flip angle approach. The T1 values of water obtained by point-resolved single-voxel spectroscopy (SVS) were used as reference values. Notably, FS methods were shown to have substantial effects on the measurement of T1 values. Among the tested FS methods, the Dixon (water) method produced T1 values most similar to SVS, which can be considered as a reference value for clinical practice.

Objective: To investigate the cost differences between magnetic resonance-guided focussed ultrasound (MRgFUS) and unilateral deep brain stimulation (DBS) for the treatment of medication-refractory essential tremor (ET) in Japan using a cost-minimisation model., Methods: A cost-minimisation model estimated total costs for MRgFUS and unilateral DBS by summing the pre-procedure, procedure, and post-procedure costs over a 12-month time horizon, using data from published sources and expert clinical opinion. The model base case considered medical costs from fee-for-service tariffs. Scenario analyses investigated the use of Diagnosis Procedure Combination tariffs, a diagnosis-related group-based fixed-payment system, and the addition of healthcare professional labour costs healthcare professionals using tariffs from the Japanese Health Insurance Federation for Surgery. One-way sensitivity analyses altered costs associated with tremor recurrence after MRgFUS, the extraction rate following unilateral DBS, the length of hospitalisation for unilateral DBS and the procedure duration for MRgFUS. The impact of uncertainty in model parameters on the model results was further explored using probabilistic sensitivity analysis., Results: Compared to unilateral DBS, MRgFUS was cost saving in the base case and Diagnosis Procedure Combination cost scenario, with total savings of JPY400,380 and JPY414,691, respectively. The majority of savings were accrued at the procedural stage. Including labour costs further increased the cost differences between MRgFUS and unilateral DBS. Cost savings were maintained in each sensitivity analysis and the probabilistic sensitivity analysis, demonstrating that the model results are highly robust., Conclusions: In the Japanese healthcare setting, MRgFUS could be a cost saving option versus unilateral DBS for treating medication-refractory ET. The model results may even be conservative, as the cost of multiple follow-ups for unilateral DBS and treatment costs for adverse events associated with each procedure were not included. This model is also consistent with the results of other economic analyses of MRgFUS versus DBS in various settings worldwide., Competing Interests: Ataru Igarashi – received financial support for this work through research grants from INSIGHTEC Ltd, Israel. Has also received research grants outside this research from Pfizer Japan Inc; Intuitive Surgical Inc; Taiho Yakuhin Inc; Boston Scientific Inc; SONY Inc; Incitec Japan Inc; Milliman Inc; Gilead Sciences KK; Terumo Inc; Fuji Film Inc; Omnica Co, Ltd and CSL Boering Inc. Received compensation for invited lectures and served as an advisor for Novartis Pharma Japan Inc; Pfizer Japan Inc; Sanofi Japan Inc; Novo Nordisk Japan Inc; Abbvie GK and Ono Pharma Inc. Midori Tanaka – none. Keiichi Abe – none. Lance Richard – employee of INSIGHTEC Ltd (the funder of this study); involved in the decision to publish this manuscript, preparation of this manuscript (original draft preparation only) and study design, but had no influence on the data collection and analysis involved in generating model results. Vivian Peirce – employee of Costello Medical Consulting Ltd; involved in data analysis and preparation of the manuscript (original draft preparation and review & editing), but had no influence on the study design, data collection or the decision to publish. Kazumichi Yamada – none. Individuals mentioned in acknowledgements (not authors) Molly Atkinson – employee of Costello Medical Consulting Ltd; provided medical writing assistance and editorial assistance in preparing the manuscript for publication, based on the authors’ input and direction. Natalie Hearmon – employee of Costello Medical Consulting Ltd; provided model programming assistance in response to changes requested by the peer reviewers. Overall, the competing interests as specified above do not alter our adherence to PLOS One policies on sharing data and materials. Furthermore, the above competing interest statement provides a complete and specific description of the involvement of INSIGHTEC Ltd and Costello Medical Consulting Ltd, as no other individuals from either company were involved in the study design, data collection and analysis, decision to publish or preparation of the manuscript.

In ulcerative colitis, an inflammatory bowel disease of unknown cause, diagnosis of the degree and location of colitis at an early stage is required to control the symptoms. Changes in redox status, including the production of reactive oxygen and nitrogen species (RONS), have been associated with ulcerative colitis in humans and dextran sodium sulfate (DSS)-induced colitis in rodents. In this study, the in vivo redox status of colons of DSS-induced colitis mice were monitored by Overhauser-enhanced magnetic resonance imaging (OMRI), and the relationship between redox status and colitis development was investigated. Colitis was induced by administering 5% DSS in drinking water to male Slc:ICR mice, which are a strain classified as closed colony outbred mice (5-week-old, 25-30 g). On the 3rd day of the DSS challenge, when no symptoms of colitis were displayed, the contrast decays of 15 N-CmP and 14 N-CxP tended to show enhancement in the whole colon and were not altered by DMSO. On the 5th day of the DSS challenge, with histological damage of the rectum being displayed, the contrast decay of 15 N-CmP was significantly enhanced not only in the rectum, but also in the proximal colon, and this was suppressed by DMSO. On the 7th day of the DSS challenge, with the mice displaying severe colitis symptoms, the image contrasts of 15 N-labeled 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl ( 15 N-CmP) and 14 N-labeled 3-carboxyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl ( 14 N-CxP) showed much faster decay than those of healthy mice, while the increased decays of both probes were restored by the membrane-permeable reactive oxygen species (ROS) scavenger dimethyl sulfoxide (DMSO). Image differencing between the decay rate images of 15 N-CmP and 14 N-CxP showed the DSS-induced redox imbalance spreading over the whole colon, and a histogram of the difference image showed a smaller peak and broader distribution with the DSS treatment. These data indicate that ROS are produced intracellularly in the distal and proximal colon in the initiation stage of DSS-induced colitis, and that ROS are produced intracellularly and extracellularly in the advanced stage of DSS-induced colitis., (Copyright © 2019. Published by Elsevier Inc.)

Six Thoroughbred racehorses with palmar process fractures of the distal phalanx were evaluated with standing magnetic resonance imaging (sMRI). In all the cases, the fractures were detectable on T1-weighted images and fat-suppressed images. Furthermore, multi-planar reconstruction images were useful for assessing the articular involvement of the fractures. Follow-up sMRI was obtainable in 3 cases, which revealed that the area of high signal intensity on fat-suppressed images decreased over time as symptoms improved. Our findings support the use of sMRI for the detailed evaluation of distal phalanx fractures including their articular involvement and the healing process.

Purpose: To evaluate whether susceptibility-weighted MR imaging (SWI) findings are associated with tumor infarction on contrast-enhanced MRI (CE-MRI) after uterine artery embolization (UAE) for leiomyoma., Methods: This was a single institution, retrospective study. Between February 2016 and April 2017, 27 consecutive patients underwent UAE and completed SWI and CE-MRI before and 1 week after UAE. Two blinded readers independently reviewed the MRI of 261 tumors ≥1 cm in all patients. We evaluated the relationship between the hypointense peripheral rim observed on the tumor surface on post-procedural SWI and the infarction rates (≥90%, <90%) of each tumor based on post-procedural CE-MRI. Inter-reader correlation coefficients (ICC) and the sensitivity and specificity of the rim were measured., Results: Substantial inter-reader agreement was noted in post-procedural SWI interpretations (ICC = 0.681, 95% CI; 0.547, 0.771). The rim was observed in 66.7% (174/261) of tumors by reader 1 and 55.9% (146/261) of tumors by reader 2 on post-procedural SWI. Correlations were observed between the rim and ≥90% tumor infarction by readers 1 and 2 (Spearman's coefficient = 0.474 and 0.438, p < 0.001 and p < 0.001, respectively). The sensitivity and specificity of the rim to tumor infarction were 77.2 and 82.6% (reader 1), and 65.8 and 100% (reader 2), respectively., Conclusions: The present study demonstrated that the hypointense peripheral rim was observed on some leiomyomas on SWI immediately after UAE. The rim correlated with tumor infarction on post-procedural CE-MRI. This SWI finding was helpful for evaluating embolic effects on leiomyomas in the acute phase after UAE., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Carotid intraplaque hemorrhage (IPH) plays a critical role in the progression of carotid atherosclerotic disease. IPH was associated with high intensity signal (HIS) in the plaque on Maximum intensity projection (MIP) images from routine three dimensional magnetic resonance imaging (3D-TOF MRA). The aim of this study was to evaluate the relationships among HIS, new ipsilateral ischemic stroke and a progression rate in carotid plaques with moderate stenosis. We included 45 carotid plaques with moderate stenosis (50%-69%) in 45 patients who could be followed more than 12 months. Carotid IPH was defined as the presence of HIS on 3DTOF MRA using the criteria previously we published. We analyzed the relation between the presence of HIS and new ischemic strokes and annual progression rate of carotid stenosis. HIS was present in 21 (47%) carotid arteries. Over a follow-up period of 24 ± 9 months, six ischemic strokes occurred in ipsilateral side. New ipsilateral ischemic stroke occurred more frequently in HIS positive group (P group: 6 of 21, 29%) than negative group (N group: 0 of 24, 0%) (p = 0.017). Annual progression rate of carotid stenosis is significantly higher in P group (+3.35%/year) than N group (-0.02%/year) (p = 0.0026). In multivariate regression analysis, HIS positive was an independent predictor for annual progression rate of carotid stenosis (p = 0.003). Evaluation of HIS in asymptomatic moderate carotid stenosis can potentially provide risk stratification of new ipsilateral ischemic strokes., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Case Reports: We report four patients with mucinous adenocarcinoma of the prostate, focusing on their magnetic resonance imaging (MRI) findings. The lesions appeared hyperintense on T2-weighted images (T2WI) in all four patients. In the two patients in whom the tumors were confined to the peripheral zone (PZ), the lesions were isointense to the surrounding normal PZ, making them difficult to identify. In all three patients who underwent diffusion-weighted imaging (b = 1000), the lesions appeared hyperintense but visually there was little or no decrease in the apparent diffusion coefficient (ADC), with ADC values of 1.02, 1.39, and 1.66 × 10 -3  mm 2 /s, respectively. In the three patients who underwent a dynamic contrast-enhanced MR study, early enhancement was evident in two (partial in one), and gradually increasing enhancement in one., Conclusion: In the four cases in this instance, MRI findings of mucinous adenocarcinoma were very different from the appearance of non-mucinous adenocarcinoma. It is suggested that the conventional interpretation method of MRI for prostate cancer is not suitable for mucinous adenocarcinoma. Those who interpret prostate MRI should be aware of this rare and unique subtype of prostate cancer.

Methods:: The cases of eight patients who underwent MRI and surgery for acute scrotum between January 2010 and January 2017 were evaluated. We recorded whether hyperintense fluid on T 2 weighted images existed between the posterior aspect of the epididymis and the scrotal wall ("split sign") and investigated if it correlated with BCD in surgical findings., Results:: In one patient without hydrocele, readers were unable to evaluate the anatomy of the tunica vaginalis. Among seven patients with hydrocele, five had the split sign and all were surgically confirmed as BCD. In two patients with hydrocele but no split sign, one had normal scrotal anatomy and the other had a BCD with a necrotic testis adherent to the scrotal wall., Conclusion:: The split sign on MRI corresponded well to the lack of fixation of the epididymis to the scrotal wall and detected BCD with high sensitivity (5/6)., Advances in Knowledge:: A hyperintense area on T 2 weighted image between the posterior aspect of the epididymis and scrotal wall ("split sign") is a useful MRI finding for diagnosing BCD.

A previously healthy, 77-year-old woman presented with gradual cognitive decline and acute gait imbalance. On admission, despite no obvious paralysis, she tilted to the right. Her Mini-Mental State Examination score was slightly low (23/30). Gadolinium-enhanced, high-resolution T 1 -weighted MRI showed abnormal arterial wall enhancement at the bilateral middle cerebral and right internal carotid arteries. The combination of arterial and parenchymal enhancement limited to the central nervous system (CNS), normal laboratory data including soluble interleukin-2 receptor, and random skin and bone-marrow biopsies was suggested of primary angiitis of the CNS (PACNS). However, a biopsy specimen from the right insula showed CD20-positive lymphoma cells indicative of diffuse large B-cell lymphoma. After receiving chemotherapy, above-mentioned abnormal findings were significantly improved. Considering the increasing clinical application of high resolution MRI, there is a risk that patients may receive a presumptive diagnosis of PACNS and immunosuppressive treatment without biopsy confirmation. It should be noted that a combination of abnormal arterial wall and linear parenchymal enhancement similar to that found for PACNS on high-resolution MRI may occur in patients with primary central nervous system lymphoma.

Background: Magnetic resonance imaging-guided focused ultrasound thalamotomy is approved by the U.S. Food and Drug Administration for treatment of essential tremor. Although this incisionless technology creates an ablative lesion, it potentially avoids serious complications of open stereotactic surgery., Objective: To determine the safety profile of magnetic resonance imaging-guided focused ultrasound unilateral thalamotomy for essential tremor, including frequency, and severity of adverse events, including serious adverse events., Methods: Analysis of safety data for magnetic resonance imaging-guided focused ultrasound thalamotomy (186 patients, five studies)., Results: Procedure-related serious adverse events were very infrequent (1.6%), without intracerebral hemorrhages or infections. Adverse events were usually transient and were commonly rated as mild (79%) and rarely severe (1%). As previously reported, abnormalities in sensation and balance were the commonest thalamotomy-related adverse events., Conclusion: The overall safety profile of magnetic resonance imaging-guided focused ultrasound thalamotomy supports its role as a new option for patients with medically refractory essential tremor. © 2018 International Parkinson and Movement Disorder Society., (© 2018 International Parkinson and Movement Disorder Society.)

Background: The Executive Interview (EXIT25), the executive clock-drawing task (CLOX1), and the Frontal Assessment Battery (FAB) are used to assess executive function at the bedside. These tests assess distinct psychometric properties. The aim of this study was to examine differences in the neural correlates of the EXIT25, CLOX1, and FAB based on magnetic resonance imaging., Methods: Fifty-eight subjects (30 with Alzheimer's disease, 10 with mild cognitive impairment, and 18 healthy controls) participated in this study. Multiple regression analyses were performed to examine the brain regions correlated with the EXIT25, CLOX1, and FAB scores. Age, gender, and years of education were included as covariates. Statistical thresholds were set to uncorrected P-values of 0.001 at the voxel level and 0.05 at the cluster level., Results: The EXIT25 score correlated inversely with the regional grey matter volume in the left lateral frontal lobe (Brodmann areas 6, 9, 44, and 45). The CLOX1 score correlated positively with the regional grey matter volume in the right orbitofrontal cortex (Brodmann area 11) and the left supramarginal gyrus (Brodmann area 40). The FAB score correlated positively with the regional grey matter volume in the right precentral gyrus (Brodmann area 6). The left lateral frontal lobe (Brodmann area 9) and the right lateral frontal lobe (Brodmann area 46) were identified as common brain regions that showed association with EXIT25, CLOX1, and FAB based only a voxel-level threshold., Conclusions: The results of this study suggest that the EXIT25, CLOX1, and FAB may be associated with the distinct neural correlates of the frontal cortex., (© 2018 Japanese Psychogeriatric Society.)

Purpose To evaluate pineal volume in patients with Alzheimer disease (AD), patients with mild cognitive impairment (MCI), and healthy control subjects and to correlate the findings with results of cognitive testing and brain parenchymal volumes. Materials and Methods The ethics committee approved this retrospective study. The participants included 63 patients with AD, 33 patients with MCI, and 24 healthy control subjects. There were 36 men and 84 women, with a mean age (±standard deviation) of 76.7 years ± 7.6. The pineal gland volume and pineal parenchymal volume were measured by using three-dimensional volumetric magnetic resonance imaging (T1-weighted magnetization-prepared rapid gradient-echo sequence; spatial resolution, 0.9 × 0.98 × 0.98 mm). With age and total intracranial volume as covariates, analysis of covariance with the Bonferroni post hoc test was performed to compare the pineal volume among the AD, MCI, and control groups. Multiple regression analyses were used to identify predictor variables associated with pineal volume. Results The mean pineal gland volume in patients with AD (72.3 mm 3 ± 5.4; 95% confidence interval [CI]: 61.5 mm 3 , 83.1 mm 3 ) was significantly smaller than that in control subjects (102.1 mm 3 ± 9.0; 95% CI: 84.4 mm 3 , 119.9 mm 3 ) (P = .019). The mean pineal parenchymal volume in patients with AD (63.8 mm 3 ± 4.2; 95% CI: 55.4 mm 3 , 72.1 mm 3 ) was significantly smaller than that in patients with MCI (81.7 mm 3 ± 5.8; 95% CI: 70.3 mm 3 , 93.1 mm 3 ; P = .044) and control subjects (89.1 mm 3 ± 6.9; 95% CI: 75.4 mm 3 , 102.9 mm 3 ; P = .009). Multiple regression analyses demonstrated that the Mini-Mental State Examination score and total intracranial volume were significant independent predictors of both pineal gland volume and pineal parenchymal volume (P < .001). Conclusion Pineal volume reduction showed correlation with cognitive decline and thus might be useful to predict cognitive decline in patients with AD. © RSNA, 2017.

Purpose: To perform a systematic analysis of the intrinsic contrast parameters of the FLAIR hyperintense rim (FHR), a thin layer of high intensity covering the entire surface of the cerebral cortex detected on fluid-attenuated inversion recovery (FLAIR) sequence T 2 weighted imaging performed on a 7T system, in an attempt to identify its anatomical correlate., Methods: Fast spin echo inversion recovery (FSE-IR) and cardiac-gated fast spin echo (FSE) images were obtained with defined parameters in eight normal volunteers on a 7 T MRI system to determine T2 and proton density, T 1 characteristics. K-means clustering analysis of parameter sets was performed using MATLAB version R2015b for the purpose of identifying the cluster reflecting FHR. The results were subsequently confirmed by independent component analysis (ICA) based on T 1 behavior on FSE-IR using a MATLAB script of FastICA algorithm., Results: The structure giving rise to FHR was found to have a unique combination of intrinsic contrast parameters of low proton density, long T 2 , and disproportionally short T 1 . The findings are in strong agreement with the functional and structural specifics of the glia limitans externa (GLE), a structure composed of snuggled endfeet of astrocytes containing abundant aquaporin-4 (AQP-4), the main water channel of the brain., Conclusion: Intrinsic contrast parameters of FHR reflect structural and functional specifics of the GLE, and their values are highly dependent on the physiologic functionality of AQP-4. Microscopic imaging on a 7T system and analysis of GLE contrast parameters can be developed into a method for evaluating AQP-4 functionality., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: To compare the plain knee radiograph finding of tibial eminence width between knees with complete discoid lateral meniscus, incomplete discoid lateral meniscus, and normal lateral meniscus., Materials and Methods: The study included 27 knees with discoid lateral meniscus, including 13 knees with complete discoid lateral meniscus and 14 knees with incomplete discoid lateral meniscus. A control group of 14 knees with normal lateral meniscus was also included. Tibial eminence width and the lateral slope angle of the medial tibial eminence were assessed using plain frontal knee radiographs. Individual differences in knee size were corrected by dividing tibial eminence width by tibial width to obtain the tibial eminence width percentage., Results: Mean tibial eminence width and tibial eminence width percentage in the complete discoid lateral meniscus group was significant larger than other groups. Mean lateral slope angle in the complete discoid lateral meniscus group was significantly smaller than other groups. A tibial eminence width cut-off of 13.9 mm showed a sensitivity and specificity of 100% and 83%, respectively. A tibial eminence width percentage cut-off of 18.8% showed a sensitivity and specificity of 100% and 90%, respectively. A lateral slope angle cut-off of 27.1° showed a sensitivity and specificity of 71% and 83%, respectively., Conclusion: There were clear differences in tibial eminence width, tibial eminence width percentage, and lateral slope angle between the complete discoid lateral meniscus group and the other groups. The plain radiographic parameters identified by this study could be useful for complete discoid lateral meniscus screening., Study Design: Clinical., (Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background Context: No previous studies have reported the radiological features of patients requiring surgery in symptomatic lumbar foraminal stenosis (LFS)., Purpose: This study aims to investigate the diagnostic accuracy of a novel technique, foraminal stenotic ratio (FSR), using three-dimensional magnetic resonance imaging for LFS at L5-S by comparing patients requiring surgery, patients with successful conservative treatment, and asymptomatic patients., Study Design: This is a retrospective radiological comparative study., Patient Sample: We assessed the magnetic resonance imaging (MRI) results of 84 patients (168 L5-S foramina) aged ≥40 years without L4-L5 lumbar spinal stenosis. The foramina were divided into three groups following standardized treatment: stenosis requiring surgery (20 foramina), stenosis with successful conservative treatment (26 foramina), and asymptomatic stenotic foramen (122 foramina)., Outcome Measures: Foraminal stenotic ratio was defined as the ratio of the length of the stenosis to the length of the foramen on the reconstructed oblique coronal image, referring to perineural fat obliterations in whole oblique sagittal images. We also evaluated the foraminal nerve angle and the minimum nerve diameter on reconstructed images, and the Lee classification on conventional T1 images., Materials and Methods: The differences in each MRI parameter between the groups were investigated. To predict which patients require surgery, receiver operating characteristic (ROC) curves were plotted after calculating the area under the ROC curve., Results: The FSR showed a stepwise increase when comparing asymptomatic, conservative, and surgical groups (mean, 8.6%, 38.5%, 54.9%, respectively). Only FSR was significantly different between the surgical and conservative groups (p=.002), whereas all parameters were significantly different comparing the symptomatic and asymptomatic groups. The ROC curve showed that the area under the curve for FSR was 0.742, and the optimal cutoff value for FSR for predicting a surgical requirement in symptomatic patients was 50% (sensitivity, 75%; specificity, 80.7%)., Conclusions: The FSR determined LFS requiring surgery among symptomatic patients, with moderate accuracy. Foramina occupied ≥50% by fat obliteration were likely to fail conservative treatment, with a positive predictive value of 75%., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to investigate whether and what carotid plaque characteristics predict systemic cardiovascular outcomes in patients with clinically established atherosclerotic disease., Background: Advancements in atherosclerosis imaging have allowed assessment of various plaque characteristics, some of which are more directly linked to the pathogenesis of acute cardiovascular events compared to plaque burden., Methods: As part of the event-driven clinical trial AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes), subjects with clinically established atherosclerotic disease underwent multicontrast carotid magnetic resonance imaging (MRI) to detect plaque tissue composition and high-risk features. Prospective associations between MRI measurements and the AIM-HIGH primary endpoint (fatal and nonfatal myocardial infarction, ischemic stroke, hospitalization for acute coronary syndrome, and symptom-driven revascularization) were analyzed using Cox proportional hazards survival models., Results: Of the 232 subjects recruited, 214 (92.2%) with diagnostic image quality constituted the study population (82% male, mean age 61 ± 9 years, 94% statin use). During median follow-up of 35.1 months, 18 subjects (8.4%) reached the AIM-HIGH endpoint. High lipid content (hazard ratio [HR] per 1 SD increase in percent lipid core volume: 1.57; p = 0.002) and thin/ruptured fibrous cap (HR: 4.31; p = 0.003) in carotid plaques were strongly associated with the AIM-HIGH endpoint. Intraplaque hemorrhage had a low prevalence (8%) and was marginally associated with the AIM-HIGH endpoint (HR: 3.00; p = 0.053). High calcification content (HR per 1 SD increase in percent calcification volume: 0.66; p = 0.20), plaque burden metrics, and clinical risk factors were not significantly associated with the AIM-HIGH endpoint. The associations between carotid plaque characteristics and the AIM-HIGH endpoint changed little after adjusting for clinical risk factors, plaque burden, or AIM-HIGH randomized treatment assignment., Conclusions: Among patients with clinically established atherosclerotic disease, carotid plaque lipid content and fibrous cap status were strongly associated with systemic cardiovascular outcomes. Markers of carotid plaque vulnerability may serve as novel surrogate markers for systemic atherothrombotic risk., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: Q-space imaging (QSI) is a novel magnetic resonance imaging (MRI) technique that enables assessment of micro-structural changes of white matter. The acquisition time, however, is comparatively long to use for routine clinical assessment. Therefore, the present study investigated the clinically feasible b value combinations to measure the water molecular displacement probability density function (PDF) in healthy subjects., Methods: The subjects consisted of five healthy volunteers (1 female and 4 male; 40.8 ± 13.2 years). All MRIs were examined at 1.5 T. The QSI was acquired using a single-shot echo-planar imaging and Δ/δ = 142/17 ms. The magnitude of the gradients was incremented in nine steps to reach a maximal b = 10,000 s/mm 2 . The total acquisition time of this original QSI was 17.4 min. The feasibility of ten alternative b value combinations with the zero-filling or curve fitting technique was assessed. The mean diffusivities (MDs), kurtosis, and zero displacement probability (ZDP) were obtained, and these results were compared in manually segmented regions of interest., Results: There were alternative b value combinations with a 7.5-min acquisition time and with almost the same PDF., Conclusion: A few alternative b value combinations with the curve fitting technique were found to be able to shorten the QSI acquisition for its clinical feasibility of MD and ZDP.

Desmitis of the oblique distal sesamoidean ligaments (ODSL) is caused by hyperextension of the metacarpophalangeal/metatarsophalangeal joint and has been described as a significant cause of lameness in racehorses. In this study, three Thoroughbred racehorses (age range: 3-6 years) were diagnosed with desmitis of the forelimb ODSL using standing low-field magnetic resonance imaging (sMRI). Radiography and ultrasonography were inconclusive with regard to a definitive diagnosis. For all horses, the sMRI characteristics included increased signal intensity within the medial ODSL on T1-weighted gradient echo, T2-weighted fast spin echo and short tau inversion recovery fast spin echo images, which use a fat suppression technique. Effusion of the digital flexor tendon sheath was also clearly visible on sMRI. Following rest and controlled exercise for roughly 3 months, two horses successfully returned to racing within 5 months. Our findings support the use of sMRI for diagnosing ODSL injuries in Thoroughbred racehorses.

In this pilot study, we compared the infarct and edema size in acute myocardial infarction (MI) patients treated by nicorandil with those treated by nitrate, using cardiac magnetic resonance (CMR) imaging. Fifty-two acute MI patients who underwent emergency percutaneous coronary intervention (PCI) were enrolled, and were assigned to receive nicorandil or nitrate at random just before reperfusion. For the assessment of infarct and edema areas, short-axis delayed enhancement (DE) and T2-weight (T2w) CMR images were acquired 6.1 ± 2.4 days after the onset of MI. A significant correlation was observed between the peak creatinine kinase (CK) level and the infarct size on DE CMR (r = 0.62, p < 0.05), as well as the edema size on T2w CMR (r = 0.70, p < 0.05) in patients treated by nicorandil (28 patients). A similar correlation was seen between the peak CK level and the infarct size on DE CMR (r = 0.84, p < 0.05), as well as the edema size on T2w CMR (r = 0.84, p < 0.05) in patients treated by nitrate (24 patients). The maximum CK level was significantly lower in patients treated by nicorandil rather than nitrate (1991 ± 1402, 2785 ± 2121 IU/L, respectively, p = 0.03). Both the edema size on T2w CMR and the infarct size on DE CMR were significantly smaller in patients treated by nicorandil rather than nitrate (17.7 ± 9.9, 21.9 ± 13.7 %; p = 0.03, 10.3 ± 6.0, 12.7 ± 6.9 %, p = 0.03, respectively). The presence and amount of microvascular obstruction were significantly smaller in patients treated by nicorandil rather than nitrate (39.2, 64.7 %; p = 0.03; 2.2 ± 1.3, 3.4 ± 1.5 cm(2); p = 0.02, respectively). Using CMR imaging, we demonstrated that the complementary use of intravenously and intracoronary administered nicorandil during PCI favorably acts more on the damaged myocardium after MI than nitrate. We need a further powered prospective study on the use of nicorandil.

Purpose: The detailed in vivo T1 -weighted contrasting abilities of nitroxyl contrast agents, which have been used as redox responsive contrast agents in several magnetic resonance-based imaging modalities, in mouse brain were investigated., Methods: Distribution and pharmacokinetics of five types of five-membered-ring nitroxyl radical compound were compared using T1 -weighted MRI., Results: The blood-brain barrier (BBB) -impermeable 3-carboxy-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CxP) could not be distributed in the brain. The slightly lipophilic 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CmP) showed slight distribution only in the ventricle, but not in the medulla and cortex. The amphiphilic 3-methoxy-carbonyl-2,2,5,5-tetramethyl-pyrrolidine-N-oxyl (MCP) had good initial uniform distribution in the brain and showed typical 2-phase signal decay profiles. A brain-seeking nitroxyl probe, acetoxymethyl-2,2,5,5-tetramethyl-pyrrolidine-N-oxyl-3-carboxylate (CxP-AM), showed an accumulating phase, and then its accumulation was maintained in the medulla and ventricle regions, but not in the cortex. The lipophilic 4-(N-methyl piperidine)-2,2,5,5-tetramethylpyrroline-N-oxyl (23c) was well distributed in the cortex and medulla, but slightly in the ventricle, and showed relatively rapid linear signal decay., Conclusion: Nitroxyl contrast agents equipped with a suitable lipophilic substitution group could be BBB-permeable functional contrast agents. MR redox imaging, which can estimate not only the redox characteristics but also the detailed distribution of the contrast agents, is a good candidate for a theranostic tool. Magn Reson Med 76:935-945, 2016. © 2015 Wiley Periodicals, Inc., (© 2015 Wiley Periodicals, Inc.)

Background: Magnetic resonance imaging (MRI) enables a more sensitive detection of brain metastasis and stereotactic irradiation (SRI) efficiently controls brain metastasis. In limited-stage small cell lung cancer (LS-SCLC), prophylactic cranial irradiation (PCI) in patients with good responses to initial treatment is recommended based on the survival benefit shown in previous clinical trials. However, none of these trials evaluated PCI effects using the management of brain metastasis with MRI or SRI. This study aimed to determine the effects of MRI and SRI on the benefits of PCI in patients with LS-SCLC., Methods: The clinical records of pathologically proven SCLC from January 2006 to June 2013 in facilities equipped with or had access to SRI in Japan were retrospectively reviewed. Patients with LS-SCLC and complete or good partial responses after initial treatment were included in the study and analyzed by the Kaplan-Meier method., Results: Of 418 patients with SCLC, 124 met criteria and were divided into patients receiving PCI (PCI group; n = 29) and those without PCI (non-PCI groups; n = 95). At baseline, ratios of patients with stage III were significantly advantageous for the non-PCI group, although younger age and high ratios of complete response and MRI confirmed absence of brain metastasis were advantageous for the PCI group. Neither median survival times (25 vs. 34 months; p = 0.256) nor cumulative incidence of brain metastasis during 2 years (45.5 vs. 30.8%; p = 0.313) significantly differed between the two groups. Moreover, these factors did not significantly differ among patients with stage III disease (25 vs. 26 months; p = 0.680, 42.3 vs. 52.3%; p = 0.458, respectively)., Conclusion: PCI may be less beneficial in patients with LS-SCLC if the management with MRI and SRI is available.

Objective: The objective of this study was to characterize MRI findings of inverted urothelial papilloma of the bladder., Materials and Methods: Data pertaining to 16 patients with 18 pathologically proven inverted urothelial papillomas of the bladder who had undergone MRI were retrospectively collected from seven institutions. The shape and surface characteristics of the tumors were evaluated using T2-weighted MR images. In addition, the signal intensity of inverted urothelial papillomas was visually assessed on T1-weighted, T2-weighted, and DW images and on early and delayed phase contrast-enhanced images., Results: The shape of the 18 inverted urothelial papillomas of the bladder was classified as polypoid with a stalk for 16 tumors (89%) and polypoid without a stalk for two tumors (11%). All stalks were surrounded by urine in the bladder. A total of 15 of the tumor surfaces (83%) were nonpapillary and three (17%) were papillary. All 12 of the inverted urothelial papillomas for which evaluable T1-weighted images were available were isointense with the bladder wall. The lesions had a slightly higher signal intensity than the bladder wall in 15 of the patients (83%) and showed isointensity with the bladder wall in three patients (17%). A total of three patients (17%) had tiny hyperintense foci noted on T2-weighted images. All 16 of the inverted urothelial papillomas examined by DWI had very high signal intensity. All 13 of the lesions for which early phase images were obtained using dynamic contrast-enhanced MRI showed strong enhancement. When compared with early phase images, delayed phase images of the same 13 lesions showed that enhancement was stronger in two lesions (15%), similar in six lesions (46%), and weaker in five lesions (38%)., Conclusion: On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk surrounded by urine. Cystic foci are also occasionally seen within the tumor.

Background: Information regarding the longevity of transplanted pancreatic islet grafts could provide valuable information for treatment options. In our previous studies, we showed that isolated autologous pancreatic islets could be labeled with iron oxide nanoparticles and monitored after transplantation using MRI. Here, we report on in vivo monitoring of a secondary damage that occurs at the later stages because of allogeneic immune rejection., Methods: In the proof-of-principle studies, iron oxide-labeled autologous pancreatic islets were transplanted under the renal capsules of nonhuman primates. To demonstrate acute graft loss, the animals were injected with streptozotocin. Graft monitoring was performed by in vivo MRI. Next, iron oxide-labeled allogeneic islets were transplanted into the liver and monitored by MRI after withdrawal of immunosuppression., Results: In autologous model, we observed a pronounced drop in graft volume after streptozotocin challenge as assessed by MRI. In allogeneic model of islet transplantation, there was an initial islet loss after the procedure followed by relative stabilization of the graft volume. After immunosuppression was discontinued, there was a noticeable drop in graft volume that gradually continued during the course of the study. Importantly, the loss of graft volume observed on MR preceded the raise in blood glucose., Conclusions: This study demonstrated that in vivo MRI was able to reveal graft volume loss before any changes in blood glucose that can be measured by standard methods. We believe that these results could provide means for clinicians to follow islet fate noninvasively and longitudinally using clinically relevant scanners.

Brain activity patterns differ from person to person, even for an identical stimulus. In functional brain mapping studies, it is important to align brain activity patterns between subjects for group statistical analyses. While anatomical templates are widely used for inter-subject alignment in functional magnetic resonance imaging (fMRI) studies, they are not sufficient to identify the mapping between voxel-level functional responses representing specific mental contents. Recent work has suggested that statistical learning methods could be used to transform individual brain activity patterns into a common space while preserving representational contents. Here, we propose a flexible method for functional alignment, "neural code converter," which converts one subject's brain activity pattern into another's representing the same content. The neural code converter was designed to learn statistical relationships between fMRI activity patterns of paired subjects obtained while they saw an identical series of stimuli. It predicts the signal intensity of individual voxels of one subject from a pattern of multiple voxels of the other subject. To test this method, we used fMRI activity patterns measured while subjects observed visual images consisting of random and structured patches. We show that fMRI activity patterns for visual images not used for training the converter could be predicted from those of another subject where brain activity was recorded for the same stimuli. This confirms that visual images can be accurately reconstructed from the predicted activity patterns alone. Furthermore, we show that a classifier trained only on predicted fMRI activity patterns could accurately classify measured fMRI activity patterns. These results demonstrate that the neural code converter can translate neural codes between subjects while preserving contents related to visual images. While this method is useful for functional alignment and decoding, it may also provide a basis for brain-to-brain communication using the converted pattern for designing brain stimulation., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Diffusion tensor imaging (DTI) is widely used in the study of the central nervous system. DTI represents a potential diagnostic tool for the peripheral nerve. However, more detailed information is needed for application of DTI in the clinical setting. In this study, peripheral degeneration and regeneration were evaluated using DTI-based analyses in a rabbit model. The changes in DTI parameters were compared to histological and functional changes after nerve injury. We used a high magnetic field (7.04T) MRI system. Japanese white male rabbits were used as the model of sciatic nerve crush injury. MR images were obtained before injury and at 2, 4, 6 and 8 weeks post-injury. The DTI parameters of fractional anisotropy (FA), axial diffusivity (λ||), and radial diffusivity (λ⊥) were calculated. Our results showed decreased FA and increased λ⊥ during the degenerative phase after sciatic nerve injury. In contrast, increased FA and decreased λ⊥ were observed during the regenerative phase. FA changes were correlated with axon number and with motor function recovery, assessed with the toe-spreading index. This study clearly demonstrates the validity of applying DTI parameters to the in vivo evaluation of peripheral nerve regeneration. Furthermore, results suggest that DTI can be a potent tool for predicting the extent of functional recovery after peripheral nerve injury., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Study Design: A cross-sectional study., Objective: This study was aimed to quantify the extent of lumbar endplate and facet joint erosion in patients with rheumatoid arthritis (RA) using magnetic resonance imaging, to calculate the prevalence of erosion, and sought correlated factors., Summary of Background Data: Few studies have examined the lumbar spine in RA, especially the relationship between endplate and facet joint erosions and lumbar lesions induced by RA., Methods: A total of 201 patients with RA were enrolled. Lumbar endplate and facet joint erosion were defined as irregularities and low-intensity change on magnetic resonance imaging, and graded utilizing the Rheumatoid Arthritis Magnetic Resonance Imaging Score. Lumbar lesions were defined as scoliosis, spondylolisthesis, and vertebral fracture on plain x-ray. Multivariable logistic regression analysis was used to seek correlations between the erosion and spinal level, RA-related factors and x-ray findings., Results: Lumbar endplate and facet erosion were detected in 70.6% and 76.6% of individuals, respectively, and at 33.8% and 38.7% of lumbar intervertebral levels, respectively. The severity of erosion in individual patients correlated with lumbar lesions. Endplate and facet erosion at each level correlated with high disease activity, and were most common at mid-lumbar and lower-lumbar levels. Strong correlations were observed between endplate erosion and adjacent vertebral body fracture or disk degeneration, and between facet erosion and spondylolisthesis., Conclusions: Lumbar endplate and facet erosion are common in RA, and are observed more frequently at mid-low levels and when RA is poorly controlled. This pattern of erosion may play a crucial role in the generation of lumbar lesions in RA.

Objective: Equivalent cross-relaxation rate imaging (ECRI) is an MRI technique used to evaluate qualitative changes in protein-water interactions. We aimed to prospectively evaluate the utility of ECRI for classification of adipocytic tumors., Materials and Methods: Institutional Review Board approval was obtained and all patients provided informed consent. Study participants included 40 patients with adipocytic tumors who were diagnosed with lipomas (n=22), atypical lipomatous tissue/well-differentiated liposarcoma (ALT/WDL; n=9), myxoid/round cell liposarcoma (MyL; n=6), and dedifferentiated liposarcoma (DDL; n=3), and 20 control patients for whom subcutaneous fat in the buttock or thigh was analyzed., Results: Mean ECR values of lipomas, ALT/WDL, and subcutaneous fat were low, and those of MyL and DDL were high. Mean ECR values of MyL and DDL were significantly higher than those of ALT/WDL. The cut-off value was 5.1%. There was a positive correlation between ECR value, pathological grade, and cell density in adipocytic tumors., Conclusion: The ECR value positively correlates with pathological grade and cell density of adipocytic tumors. Our findings suggest that ECRI is a useful method for preoperative evaluation of adipocytic tumors., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: Equivalent cross-relaxation rate (ECR) imaging (ECRI), which allows quantitation of macromolecular tissue components, is a potentially useful nuclear magnetic resonance (NMR) technique for histopathological diagnosis. The purpose of this study was to compare ECR values among various histological types and assess the correlation between ECR and tumor cellular image in soft tissue tumors., Materials and Methods: We performed ECRI to evaluate cellular images of soft tissue tumors and tumorous lesions. Thirty-three patients who underwent evaluation with MRI and ECRI at the first visit were enrolled. Resection or biopsy was performed to obtain a histopathological diagnosis, followed by cell density measurement. ECR values of the histological subgroups were compared, and the correlation between ECR and cell density was analyzed to assess whether ECR can be used as an indicator of histological cell density., Results: ECR values for benign tumors varied widely and were not significantly different from those for malignant tumors. However, the mean ECR value was significantly higher for high-grade malignant tumors than for low-grade tumors (p < 0.01). Moreover, a positive correlation was found between ECR and cell density (r s = 0.72; p < 0.01)., Conclusions: ECR reflects the cell density and malignancy grade of a soft tissue tumor. ECRI could provide cellular imaging and useful clinical information to aid the pre-operative diagnosis of soft tissue tumors.

Nitroxides have recently been used as redox-sensitive contrast agents for both MRI and EPR imaging. However, the rapid in vivo reduction in paramagnetism of nitroxides due to reductants such as ascorbic acid (AsA) has limited their use as contrast agents. This study developed a formulation of a newly synthesized AsA-resistive nitroxide (2,2,6,6-tetraethylpiperidine-4-one-1-oxyl (TEEPONE)) with a lipid emulsion system and examined the in vivo stability of TEEPONE by magnetic resonance imaging (MRI). MRI of mouse heads after administration of TEEPONE clearly indicated that TEEPONE has a remarkable in vivo stability and is a blood-brain barrier (BBB) permeable nitroxide. MRI also showed that TEEPONE is preferentially localized in the mouse brain. The distribution of TEEPONE in the mouse head can be controlled by the lipid content in the emulsion system used to solubilize TEEPONE., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Introduction: q-Space imaging is a novel magnetic resonance (MR) technique that enables the assessment of ultrastructural changes of white matter. We hypothesized that this technique would facilitate the assessment of the progressive nature of neuronal damage seen in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)., Methods: This study was approved by the institutional review board. Seven consecutive adult patients (five men and two women) with the CADASIL gene mutation were studied. Two patients were preclinical cases without overt episodes of stroke. The control group consisted of five normal volunteers. All MR examinations were performed using a 1.5-T whole-body imager. q-Space imaging was performed using a single-shot, echo-planar imaging technique and Δ/δ = 142/17 ms. Gradient magnitudes were increased in nine steps to reach a maximal b value of 10,000 s/mm². Total acquisition time of q-space imaging was 25 min. The ADC maps calculated from the b = 1,000 images were used for comparisons., Results: Both q-space imaging and ADC maps depicted progressive neuronal damage. Early neuronal damage was especially well depicted using q-space imaging, with preferential involvement of the frontal lobes and central gray matters. Later progression was better depicted by b = 1,000 ADC maps at the temporal lobes. Visual assessment of images revealed a trend for occipital lobe sparing, especially on q-space imaging., Conclusion: q-Space imaging demonstrated early neuronal damage in a characteristic distribution. Since this method appears to be sensitive to early neuronal damage, it could conceivably aid in monitoring patients in the preclinical stage and may help in assessing the effects of future medical interventions.

Purpose: Homogeneity of static magnetic field (B(0)) is unstable for head and neck magnetic resonance (MR) examination; consequently, chemical shift selective fat suppression becomes inhomogeneous. There is a commercially available additional pad to attenuate the B(0) inhomogeneity, but it is expensive. It has been reported that uncooked rice can be used as a material in the pad, but it has hygienic and weight problems. We searched for a material which can replace the uncooked rice, and evaluated its performance., Method: After filling various materials into the cylindrical phantom, each material was evaluated by image distortion of gradient filed echo and spin echo single-shot echo planar images. A prototype additional pad was made with a material which showed less image distortion in the phantom experiment and is easily available in clinical examination. For comparison, an uncooked rice pad with the same volume was also prepared. Fat suppressed head and neck magnetic resonance imaging (MRI) of normal volunteers were visually compared when the three additional pads, including the commercial product, were used or not., Result: The polystyrene ball bullet (BB bullet) was adopted as a material for the additional pad. The improvement of the fat suppression in the head and neck MRI was almost the same between the three additional pads. BB bullet pad was the lightest., Conclusion: BB bullet can be used as a material of additional pad attenuating the B(0) inhomogeneity instead of uncooked rice.

Overhauser-enhanced MRI (OMRI) enables visualization of free radicals in animals based on dynamic nuclear polarization. Real-time data of tissue redox status gathered from kinetic images of redox-sensitive nitroxyl radical probes using OMRI provided both anatomic and physiological information. Phantom experiments demonstrated the linear correlation between the enhancement factor and the concentration of a membrane-impermeable probe, carboxy-PROXYL (3-carboxy-2,2,5,5-tetramethyl- pyrrolidine-1-oxyl). Whole-body OMRI images illustrated the in vivo kinetics of carboxy-PROXYL for 25 min. Initial distribution was observed in lung, heart, liver, and kidney, but not brain, corresponding to its minimal lipophilicity. Based on these images (pixel size, 1.33 × 1.33 mm; slice thickness, 50mm), a time-concentration curve with low coefficient of variance (<0.21) was created to assess pharmacokinetic behaviors. A biexponential curve showed a distribution phase from 1 to 10 min and an elimination phase from 15 to 25 min. The α rate constant was greater than the β rate constant in ROIs, confirming that its pharmacokinetics obeyed a two-compartment model. As a noninvasive technique, combining OMRI imaging with redox probes to monitor tissue redox status may be useful in acquiring valuable information regarding organ function for preclinical and clinical studies of oxidative diseases., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objectives: To evaluate whether magnetic resonance (MR) imaging features can predict the presence of occult invasion in cases of biopsy-proven pure ductal carcinoma in situ (DCIS)., Methods: We retrospectively reviewed 92 biopsy-proven pure DCIS in 92 women who underwent MR imaging. The following MR imaging findings were compared between confirmed DCIS and invasive breast cancer (IBC): lesion size, type, morphological and kinetic assessments by ACR BI-RADS MRI, and findings of fat-suppressed T2-weighted (FS-T2W) imaging., Results: Sixty-eight of 92 (74%) were non-mass-like enhancements (NMLE) and 24 were mass lesions on MR imaging. Twenty-one of 68 (31%) NMLE and 13 of 24 (54%) mass lesions were confirmed as IBC. In NMLE lesions, large lesions (P = 0.007) and higher signal intensities (SI) on FS-T2W images (P = 0.032) were significantly associated with IBC. Lesion size remained a significant independent predictor of invasion in multivariate analysis (P = 0.032), and combined with FS-T2W SIs showed slightly higher observer performances (area under the curve, AUC, 0.71) than lesion size alone (AUC 0.68). There were no useful findings that enabled the differentiation of mass-type lesions., Conclusions: Breast MR imaging is potentially useful to predict the presence of occult invasion in biopsy-proven DCIS with NMLE., Key Points: MR mammography permits more precise lesion assessment including ductal carcinoma in situ A correct diagnosis of occult invasion before treatment is important for clinicians This study showed the potential of MR mammography to diagnose occult invasion Treatment and/or aggressive biopsy can be given with greater confidence MR mammography can lead to more appropriate management of patients.

Objectives: To differentiate acute from chronic damage to the myocardium in patients with myocardial infarction (MI) using DE and T2w MR., Methods: Short-axis T2w and DE MR images were acquired twice after the onset of MI in 36 patients who successfully underwent emergency coronary revascularisation. The areas of infarct and oedema were measured. The oedema-infarct ratio (O/I) of the left ventricular area was calculated by dividing the oedema by the infarct area., Results: The oedema size on T2w MR was significantly larger than the infarct size on DE MR in the acute phase. Both the oedema size on T2w MR and the infarct size on DE MR in the acute phase were significantly larger than those in the chronic phase. The O/I was significantly greater in the acute phase compared with that in the chronic phase (P < 0.05). An analysis of relative cumulative frequency distributions revealed an O/I of 1.4 as a cut-off value for differentiating acute from chronic myocardial damage with the sensitivity, specificity, and accuracy of 85.1%, 82.7% and 83.9%, respectively., Conclusion: The oedema-infarct ratio may be a useful index in differentiating acute from chronic myocardial damage in patients with MI., Key Points: MR can differentiate reversible from irreversible myocardial damage after myocardial infarction. MR is a useful modality to noninvasively differentiate the infarct stages. The O/I is an important index to decide therapeutic strategies.

Oxidative stress may be involved in the dopaminergic neurodegenerations seen in 6-OHDA-lesioned rats through its production of free radicals and through mitochondrial dysfunction. In this study, we noninvasively demonstrate brain redox alterations in 6-OHDA-lesioned rats using Overhauser-enhanced magnetic resonance imaging (OMRI). The reduction rate of 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-l-oxyl (methoxycarbonyl-PROXYL), a redox-sensitive contrast agent, was used as an index of the redox status in vivo. The methoxycarbonyl-PROXYL reduction rate, calculated from continuous images, decreased significantly in lesioned hemispheres compared to their corresponding contralateral hemispheres. The reduction rates in cellular fractions obtained from the striatum were estimated by X-band electron spin resonance (ESR) and calculated by assuming first-order kinetics for their time-dependent decreases. When methoxycarbonyl-PROXYL was mixed with cytoplasm fractions, the reduction rates were the same in both hemispheres. However, the ESR signal of methoxycarbonyl-PROXYL in the mitochondrial fraction of the lesioned hemispheres decayed more slowly than that of the corresponding contralateral hemispheres. Concordantly, biochemical assays showed that the activity of mitochondrial complex I also decreased more slowly in lesioned hemispheres. Thus, this method of noninvasively imaging brain redox alterations faithfully reflects changes in mitochondrial complex I activity in 6-OHDA-lesioned rats., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The basal ganglia represents a key component of the pathophysiological model for obsessive-compulsive disorder (OCD). This brain region is part of several neural circuits, including the orbitofronto-striatal circuit and dorsolateral prefronto-striatal circuit. There are, however, no published studies investigating those circuits at a network level in non-medicated patients with OCD. Resting state functional magnetic resonance imaging scans were obtained from 20 non-medicated patients with OCD and 23 matched healthy volunteers. Voxelwise statistical parametric maps testing strength of functional connectivity of three striatal seed regions of interest (ROIs) with remaining brain regions were calculated and compared between groups. We performed additional correlation analyses between strength of connectivity and the severity scores for obsessive-compulsive symptoms, depression, and anxiety in the OCD group. Positive functional connectivity with the ventral striatum was significantly increased (P(corrected) < .05) in the orbitofrontal cortex, ventral medial prefrontal cortex and dorsal lateral prefrontal cortex of subjects with OCD. There was no significant correlation between measures of symptom severity and the strength of connectivity (P(uncorrected) < .001). This is the first study to investigate the corticostriatal connectivity in non-medicated patients with OCD. These findings provide the first direct evidence supporting a pathophysiological model involving basal ganglia circuitry in OCD., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Background: For men with clinically localized prostate cancer and candidates to receive radical prostatectomy (RP) a main concern is a cancer recurrence after treatment. Although previous studies have demonstrated the diagnostic utility of diffusion-weighted imaging (DWI) for prostate cancer, the prognostic value of pretreatment DWI has not been investigated yet., Purpose: To investigate the incremental value of MRI-based T staging using DWI and T2-weighted imaging (T2WI) as compared with the clinical parameters in prediction of biochemical recurrence (BCR) after RP for clinically localized prostate cancer., Material and Methods: Sixty MR examinations, obtained before RP between April 2002 and March 2009, were retrospectively reviewed using T2WI alone, DWI alone, or T2WI + DWI for T staging according to the 2002 American Joint Committee on Cancer guidelines. The relationship between MRI stage and BCR was evaluated using Kaplan-Meier survival estimates. Multivariate analysis and receiver operating characteristics (ROC) curve analysis were used to investigate the incremental value over the standard clinical variables in prediction of BCR., Results: As of August 2009, 12 (20%) patients had BCR. Based on T2WI + DWI, both T3a (compared to OC disease) and T2 (compared to T1c) showed significantly higher BCR rates (p=0.047 and 0.025, respectively). Multivariate analysis and area under ROC curve analysis confirmed the additional value of MRI staging to the conventional clinical variables in prediction of BCR., Conclusion: The combination of T2WI and DWI on performing pretreatment MRI helped predict BCR after RP in clinically localized prostate cancer.