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A study published in Frontiers in Neuroscience compared the effectiveness of parametric response mapping (PRM) and conventional perfusion MRI in predicting clinical outcomes for patients with chronic ischemic stroke. The research found that PRM analysis was more accurate in predicting long-term clinical outcomes compared to traditional methods, offering valuable insights into stroke lesion heterogeneity. The study suggests that PRM analysis could improve patient stratification and guide rehabilitation efforts for stroke patients by providing additional information on stroke development and its impact on outcomes. The use of PRM metrics, such as relative cerebral blood volume (rCBV) and time-to-maximum (Tmax), as imaging biomarkers for prognosis could offer a new perspective on stroke evolution and therapeutic evaluation. [Extracted from the article]

Introduction: Distinguishing meningiomas from other intracranial neoplasms is clinically relevant as the prognostic and therapeutic implications differ greatly and influence clinical decision making. Dynamic contrast-enhanced MRI (DCEMRI) is an imaging technique that assists with characterisation of physiologic alterations such as blood flow and tissue vascular permeability. Quantitative pharmacokinetic analysis utilising DCE-MRI has not been studied in canine neuro-oncology. Methods: A retrospective study was performed in canine patients that underwent DCE-MRI with an imaging diagnosis of an intracranial meningioma and surgery for histopathological diagnosis. Kinetic parameters Ktrans and cerebral blood flow were measured and compared to assess whether differences could be identified between meningiomas and other intracranial neoplasms. Results: Six dogs with meningiomas and 3 dogs with other intracranial neoplasms were included for statistical analysis. Cerebral blood flow values were found to be statistically higher within meningiomas compared to other intracranial neoplasms. Ktrans values were higher within meningiomas than in other types of intracranial tumours, however this difference did not reach statistical significance. Discussion: Based on the results of this study cerebral blood flow measurement can be utilised to differentiate canine intracranial meningiomas from other similar appearing intracranial tumours. [ABSTRACT FROM AUTHOR]

Intraventricular neurocytoma is a low incidence central nervous system tumor. It predominantly affects young adults with no apparent gender predilection. The main symptoms include headache, nausea and vomiting. These result from hydrocephalus due to the obstruction of cerebrospinal fluid flow. On diagnostic imaging, neurocytoma can be suspected by some features, such as peripheral cysts, lobulated contours and septa that bridge the ventricular wall, giving a “scalloped” appearance. There are other characteristics, but they are less specific for the diagnosis. The atypical variant of neurocytoma is even rarer and leads to a worst prognosis. Atypical neurocytomas develop higher proliferative potential identified by the Ki-67 biomarker and higher recurrence rate. There are few studies about the imaging characteristics of atypical neurocytomas. At this point, there are no reliable distinctive features to differentiate atypical neurocytomas, especially due to their low incidence.We present the case of a 20-year-old female patient with symptoms of intracraneal hypertension. CT and MRI of the brain revealed a mass occupying the body of the left lateral ventricle, adjacent to the foramen of Monro. The mass was primarily solid with discrete peripheral cyst and a few scalloped areas. It also showed signs of supratentorial obstructive hydrocephalus. The tumor was partially removed because of bleeding and compromise of vascular structures. Immunohistochemistry revealed positive synaptophysin, elevated Ki-67 (7%), increased number of blood vessels and moderate nuclear atypia. After surgery, the patient persisted with signs of intracranial hypertension, not improving with clinical management and requiring aggressive surgical procedures.While rare, atypical neurocytoma requires a better characterization, especially through imaging, to optimize immediate management and explore new therapeutic options.

Craniosynostoses (CRS) are caused by the premature fusion of one or more cranial sutures, with isolated nonsyndromic CRS accounting for most of the clinical manifestations. Such premature suture fusion impacts both skull and brain morphology and involves regions far beyond the immediate area of fusion. The combined use of different neuroimaging tools allows for an accurate depiction of the most prominent clinical–radiological features in nonsyndromic CRS but can also contribute to a deeper investigation of more subtle alterations in the underlying nervous tissue organization that may impact normal brain development. This review paper aims to provide a comprehensive framework for a better understanding of the present and future potential applications of neuroimaging techniques for evaluating nonsyndromic CRS, highlighting strategies for optimizing their use in clinical practice and offering an overview of the most relevant technological advancements in terms of diagnostic performance, radiation exposure, and cost-effectiveness. [ABSTRACT FROM AUTHOR]

Arterial spin labeling (ASL) and dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) have shown potential for differentiating tumor progression from pseudoprogression. For pseudocontinuous ASL with a single postlabeling delay, the presence of delayed arterial transit times (ATTs) could affect the evaluation of ASL‐MRI perfusion data. In this study, the influence of ATT artifacts on the perfusion assessment and differentiation between tumor progression and pseudoprogression were studied. This study comprised 66 adult patients (mean age 60 ± 13 years; 40 males) with a histologically confirmed glioblastoma who received postoperative radio (chemo)therapy. ASL‐MRI and DSC‐MRI scans were acquired at 3 months postradiotherapy as part of the standard clinical routine. These scans were visually scored regarding (i) the severity of ATT artifacts (%) on the ASL‐MRI scans only, scored by two neuroradiologists; (ii) perfusion of the enhancing tumor lesion; and (iii) radiological evaluation of tumor progression versus pseudoprogression by one neuroradiologist. The final outcome was based on combined clinical and radiological follow‐up until 9 months postradiotherapy. ATT artifacts were identified in all patients based on the mean scores of two raters. A significant difference between the radiological evaluation of ASL‐MRI and DSC‐MRI was observed only for ASL images with moderate ATT severity (30%–65%). The perfusion assessment showed ASL‐MRI tending more towards hyperperfusion than DSC‐MRI in the case of moderate ATT artifacts. In addition, there was a significant difference between the prediction of tumor progression with ASL‐MRI and the final outcome in the case of severe ATT artifacts (McNemar test, p = 0.041). Despite using ASL imaging parameters close to the recommended settings, ATT artifacts frequently occur in patients with treated brain tumors. Those artifacts could hinder the radiological evaluation of ASL‐MRI data and the detection of true disease progression, potentially affecting treatment decisions for patients with glioblastoma. [ABSTRACT FROM AUTHOR]

Purpose: Perfusion MRI reveals important tumor physiological and pathophysiologic information, making it a critical component in managing brain tumor patients. This study aimed to develop a dual‐echo 3D spiral technique with a single‐bolus scheme to simultaneously acquire both dynamic susceptibility contrast (DSC) and dynamic contrast‐enhanced (DCE) data and overcome the limitations of current EPI‐based techniques. Methods: A 3D spiral‐based technique with dual‐echo acquisition was implemented and optimized on a 3T MRI scanner with a spiral staircase trajectory and through‐plane SENSE acceleration for improved speed and image quality, in‐plane variable‐density undersampling combined with a sliding‐window acquisition and reconstruction approach for increased speed, and an advanced iterative deblurring algorithm. Four volunteers were scanned and compared with the standard of care (SOC) single‐echo EPI and a dual‐echo EPI technique. Two patients were scanned with the spiral technique during a preload bolus and compared with the SOC single‐echo EPI collected during the second bolus injection. Results: Volunteer data demonstrated that the spiral technique achieved high image quality, reduced geometric artifacts, and high temporal SNR compared with both single‐echo and dual‐echo EPI. Patient perfusion data showed that the spiral acquisition achieved accurate DSC quantification comparable to SOC single‐echo dual‐dose EPI, with the additional DCE information. Conclusion: A 3D dual‐echo spiral technique was developed to simultaneously acquire both DSC and DCE data in a single‐bolus injection with reduced contrast use. Preliminary volunteer and patient data demonstrated increased temporal SNR, reduced geometric artifacts, and accurate perfusion quantification, suggesting a competitive alternative to SOC‐EPI techniques for brain perfusion MRI. [ABSTRACT FROM AUTHOR]

IntroductionDistinguishing meningiomas from other intracranial neoplasms is clinically relevant as the prognostic and therapeutic implications differ greatly and influence clinical decision making. Dynamic contrast-enhanced MRI (DCE-MRI) is an imaging technique that assists with characterisation of physiologic alterations such as blood flow and tissue vascular permeability. Quantitative pharmacokinetic analysis utilising DCE-MRI has not been studied in canine neuro-oncology.MethodsA retrospective study was performed in canine patients that underwent DCE-MRI with an imaging diagnosis of an intracranial meningioma and surgery for histopathological diagnosis. Kinetic parameters Ktrans and cerebral blood flow were measured and compared to assess whether differences could be identified between meningiomas and other intracranial neoplasms.ResultsSix dogs with meningiomas and 3 dogs with other intracranial neoplasms were included for statistical analysis. Cerebral blood flow values were found to be statistically higher within meningiomas compared to other intracranial neoplasms. Ktrans values were higher within meningiomas than in other types of intracranial tumours, however this difference did not reach statistical significance.DiscussionBased on the results of this study cerebral blood flow measurement can be utilised to differentiate canine intracranial meningiomas from other similar appearing intracranial tumours.

PurposeThere remains no consensus normal-appearing white matter (NAWM) normalization method to compute normalized relative cerebral blood volume (nrCBV) and apparent diffusion coefficient (nADC) in brain tumors. This reader study explored nrCBV and nADC differences using different NAWM normalization methods.MethodsThirty-five newly diagnosed glioma patients were studied. For each patient, two readers created four NAWM regions of interests: (1) a single plane in the centrum semiovale (CSOp), (2) 3 spheres in the centrum semiovale (CSOs), (3) a single plane in the slice of the tumor center (TUMp), and (4) 3 spheres in the slice of the tumor center (TUMs). Readers repeated NAWM segmentations 1 month later. Differences in nrCBV and nADC of the FLAIR hyperintense tumor, inter-/intra-reader variability, and time to segment NAWM were assessed. As a validation step, the diagnostic performance of each method for IDH-status prediction was evaluated.ResultsBoth readers obtained significantly different nrCBV (P < .001), nADC (P < .001), and time to segment NAWM (P < .001) between the four normalization methods. nrCBV and nADC were significantly different between CSO and TUM methods, but not between planar and spherical methods in the same NAWM region. Broadly, CSO methods were quicker than TUM methods, and spherical methods were quicker than planar methods. For all normalization techniques, inter-reader reproducibility and intra-reader repeatability were excellent (intraclass correlation coefficient > 0.9), and the IDH-status predictive performance remained similar.ConclusionThe selected NAWM region significantly impacts nrCBV and nADC values. CSO methods, particularly CSOs, may be preferred because of time reduction, similar reader variability, and similar diagnostic performance compared to TUM methods.

Purpose: To determine the relationship between intravoxel incoherent motion (IVIM) MRI parameters and clinical changes post-tap test (TT) in idiopathic normal-pressure hydrocephalus (iNPH) patients. Methods: Forty-four probable iNPH patients underwent 3 T MRI before and after TT. IVIM parameters were calculated from eight different bilateral regions of interest in basal ganglia, centrum semiovale, and corona radiata. Patients were categorized based on TT response into positive (group 1) and negative (group 2) groups. A Welch two-sample t-test was used to compare differences in D, D*, f, and ADC between the two groups, while a paired t-test was employed to assess the changes within each group before and after TT. These parameters were then correlated with clinical results. Results: In the lenticular and thalamic nuclei, D value was significantly lower in the group 1 compared to group 2 both pre- and post-TT (p = 0.002 and p = 0.007 respectively). Post-TT, the positive response group exhibited a notably reduced D* value (p = 0.012) and significantly higher f values (p = 0.028). In the corona radiata and centrum semiovale, a significant post-TT reduction in D* was observed in the positive response group (p = 0.017). Within groups, the positive response cohort showed a significant post-TT increase in ADC (p < 0.001) and a decrease in D* (p = 0.007). Conclusion: IVIM permits the acquisition of important non-invasive information about tissue and vascularization in iNPH patients. Enhanced perfusion in the lenticular and thalamic nuclei may suggest the role of re-established microvascular and glymphatic pathways, potentially elucidating the functional improvement in motor function after TT in iNPH patients. [ABSTRACT FROM AUTHOR]

Abstract Objective Perfusion MRI is of great benefit in the post-treatment evaluation of brain tumors. Interestingly, dynamic susceptibility contrast-enhanced (DSC) perfusion has taken its place in routine examination for this purpose. The use of arterial spin labeling (ASL), a perfusion technique that does not require exogenous contrast material injection, has gained popularity in recent years. The aim of the study was to compare two different perfusion techniques, ASL and DSC, using qualitative and quantitative measurements and to investigate the diagnostic effectiveness of both. The fact that the number of patients is higher than in studies conducted with 3D pseudo-continious ASL (pCASL), the study group is heterogeneous as it consists of patients with both metastases and glial tumors, the use of 3D Turbo Gradient Spin Echo (TGSE), and the inclusion of visual (qualitative) assessment make our study unique. Methods Ninety patients, who were treated for malignant brain tumor, were enrolled in the retrospective study. DSC Cerebral Blood Volume (CBV), Cerebral Blood Flow (CBF) and ASL CBF maps of each case were obtained. In qualitative analysis, the lesions of the cases were visually classified as treatment-related changes (TRC) and relapse/residual mass (RRT). In the quantitative analysis, three regions of interest (ROI) measurements were taken from each case. The average of these measurements was compared with the ROI taken from the contralateral white matter and normalized values (n) were obtained. These normalized values were compared across events. Results Uncorrected DSC normalized CBV (nCBV), DSC normalized CBF (nCBF) and ASL nCBF values of RRT cases were higher than those of TRC cases (p

The current study estimated incident breakthrough seizures, serum matrix metalloproteinase-9 (MMP-9), and perfusion magnetic resonance imaging (MRI) parameters in five- to 18-year-olds with neurocysticercosis (NCC) from colloidal or vesicular through calcified stages over at least 24 months' follow-up. Single, colloidal, or vesicular parenchymal NCC cases were treated with albendazole and steroids and followed at a tertiary care north Indian hospital. Serum MMP-9 was estimated in colloidal or vesicular treatment-naive state and in a subset of calcified cases at six-month follow-up. The same subset of calcified cases also underwent perfusion MRI of the brain at six-month follow-up. Among 70 cases, 70% calcified at six-month follow-up. Over a median follow-up of 30 months, the incidence of breakthrough seizures was 48.6% (61.2% in calcified and 19.2% in resolved, P = 0.001; 32.9% early [within six months] and 15.7% late [beyond six months], P = 0.02). Serum MMP-9 levels were higher in colloidal and vesicular compared with calcified stage (242.5 vs 159.8 ng/mL, P = 0.007); however, there was no significant association with breakthrough seizures and/or calcification in follow-up. In a subgroup of calcified cases (n = 31), the median relative cerebral blood volume on perfusion MRI in and around the lesion was lower in those with seizures (n = 12) than in those without (n = 19) (10.7 vs 25.2 mL/100 g, P = 0.05). In post-treatment colloidal or vesicular NCC, incident breakthrough seizures decrease beyond six months. In calcified NCC with remote breakthrough seizures, significant perilesional hypoperfusion is seen compared with those without seizures. [ABSTRACT FROM AUTHOR]

Posterior fossa tumours (PFTs), which account for two-thirds of paediatric brain tumours, are successfully treated in about 70% of patients, but most survivors experience long-term cognitive impairment. We evaluated arterial spin labelling (ASL), a common, non-invasive magnetic resonance imaging (MRI) technique, as a biomarker of cognitive impairment in a paediatric PFT survivor population. Sixty participants were prospectively analysed. PFT survivors were at least 5 years post-treatment and had been treated as appropriate for their age and type of tumour. Group 1 had received radiotherapy and Group 2 had not. Group 3 were healthy controls matched to Group 1 for age, sex and handedness. All participants underwent cognitive assessment and multimodal MRI, including an ASL perfusion sequence. We used semi-quantitative ASL methods to assess differences in mean perfusion in the thalamus, caudate, putamen and hippocampus. Statistically, no significant associations between cognitive data and radiation doses were identified. Compared with healthy controls, Group 1 patients had significantly lower overall mean perfusion values (20–30% lower, depending on the cerebral structure) and Group 2 had slightly lower mean perfusion values (5–10% lower). Perfusion values did not correlate with total prescribed irradiation doses nor with doses received by different cerebral structures. Episodic and semantic memory test scores were significantly lower in Group 1 and correlated with lower mean absolute perfusion values in the hippocampus (P < 0.04). These preliminary results indicate that radiotherapy affects the perfusion of specific cerebral structures and identify perfusion as a potential biomarker of hippocampus-dependent memory deficit. • A semi-quantitative ASL method was used to quantify cognitive loss in PFT survivors. • Radiotherapy induced long-term overall cerebral semi-quantitative hypoperfusion in a paediatric PFT population. • Perfusion values tend to correlate significantly with the mean radiation dose received by the left hippocampus but not other brain structures examined. • A decrease in hippocampal perfusion is therefore a potential marker of memory impairment in irradiated children. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Capillary dysfunction, characterized by disturbances in capillary blood flow distribution, might be an overlooked factor in the development of Alzheimer's disease (AD). This study investigated microvascular blood flow in preclinical and prodromal AD individuals. METHODS: Using dynamic susceptibility contrast magnetic resonance imaging and positron emission tomography, we examined alterations in microvascular circulation and levels of Aβ deposition in two independent cohorts of APOE ε4 carriers. RESULTS: Capillary dysfunction was elevated in both prodromal and preclinical AD individuals compared to age‐matched controls. Additionally, the prodromal group exhibited higher levels of capillary dysfunction compared to the preclinical group. DISCUSSION: These findings suggest that capillary dysfunction can be detected at the preclinical stage of AD and indicates a worsening of capillary dysfunction throughout the AD continuum. Understanding the interaction between capillary dysfunction and Aβ could provide insights into the relationship between cardiovascular risk factors and the development of AD. Highlights: Alzheimer's disease (AD) is associated with disturbances in microvascular circulation.Capillary dysfunction can be detected in preclinical AD.As cognitive symptoms progress in prodromal AD, capillary dysfunction worsens.Capillary dysfunction may impede the clearance of beta‐amyloid (Aβ).Capillary dysfunction might contribute to the development of AD. [ABSTRACT FROM AUTHOR]

Context Insulin-mediated microvascular permeability and blood flow of skeletal muscle appears to be altered in the condition of insulin resistance. Previous studies on this effect used invasive procedures in humans or animals. Objective The aim of this study was to demonstrate the feasibility of a noninvasive assessment of human muscle microcirculation via dynamic contrast-enhanced (DCE)-magnetic resonance imaging (MRI) of skeletal muscle in patients with type 2 diabetes (T2D). Methods A total of 56 participants (46 with T2D, 10 healthy controls [HC]) underwent DCE-MRI of the right thigh at 3 Tesla. The constant of the musculature's microvascular permeability (Ktrans), extravascular extracellular volume fraction (ve), and plasma volume fraction (vp) were calculated. Results In T2D patients, skeletal muscle Ktrans was lower (HC 0.0677 ± 0.002 min−1, T2D 0.0664 ± 0.002 min−1; P = 0.042) while the homeostasis model assessment (HOMA) index was higher in patients with T2D compared to HC (HC 2.72 ± 2.2, T2D 6.11 ± 6.2; P =.011). In T2D, Ktrans correlated negatively with insulin (r = −0.39, P =.018) and HOMA index (r = −0.38, P =.020). Conclusion The results signify that skeletal muscle DCE-MRI can be employed as a noninvasive technique for the assessment of muscle microcirculation in T2D. Our findings suggest that microvascular permeability of skeletal muscle is lowered in patients with T2D and that a decrease in microvascular permeability is associated with insulin resistance. These results are of interest with regard to the impact of muscle perfusion on diabetic complications such as diabetic sarcopenia. [ABSTRACT FROM AUTHOR]

Background: Legg-Calvé-Perthes disease (LCPD) progresses through 4 stages characterized by unique radiographic features, and stage duration is recognized as an important prognostic factor. Newer perfusion magnetic resonance imaging (pMRI) allows for the evaluation of vascularity early in the disease process. This study aims to describe the relationship between global and regional perfusion patterns on early pMRI and the duration of Waldenström stages. A secondary aim was to verify the relationship between hypoperfusion and subsequent lateral pillar class. Methods: Through a prospectively collected multicenter international cohort, patients with early LCPD (Waldenström Stage I) and pMRI were followed with serial radiographs at 3-month intervals for a minimum of 2 years. Epiphyseal hypoperfusion was quantified by HipVasc Software for the entire epiphysis and regional thirds of the femoral head. Waldenström stages and lateral pillar class were determined by mode assessments from 3 pediatric orthopedic surgeons. Duration of the stage was defined as the interval between the first radiograph demonstrating features of stage IIa and stage IIIa for fragmentation and between IIIa and IV for reossification. Results: One-hundred and seven patients (88.8% male, median age 8.0 years) met the study criteria. The average global hypoperfusion was 73.7%. Poorer global perfusion was predictive of a longer duration of fragmentation (rho = 0.34, P

Our study aims to reveal clinically helpful prognostic markers using quantitative radiologic data from perfusion magnetic resonance imaging for patients with locally advanced carcinoma, using the Ki-67 index as a surrogate. Patients who received a breast cancer diagnosis and had undergone dynamic contrast-enhanced magnetic resonance imaging of the breast for pretreatment evaluation and follow-up were searched retrospectively. We evaluated the MRI studies for perfusion parameters and various categories and compared them to the Ki-67 index. Axillary involvement was categorized as low (N0–N1) or high (N2–N3) according to clinical stage. A total sum of 60 patients' data was included in this study. Perfusion parameters and Ki-67 showed a significant correlation with the transfer constant (Ktrans) (ρ = 0.554 p = 0.00), reverse transfer constant (Kep) (ρ = 0.454 p = 0.00), and initial area under the gadolinium curve (IAUGC) (ρ = 0.619 p = 0.00). The IAUGC was also significantly different between axillary stage groups (Z = 2.478 p = 0.013). Outside of our primary hypothesis, associations between axillary stage and contrast enhancement (x2 = 8.023 p = 0.046) and filling patterns (x2 = 8.751 p = 0.013) were detected. In conclusion, these parameters are potential prognostic markers in patients with moderate Ki-67 indices, such as those in our study group. The relationship between axillary status and perfusion parameters also has the potential to determine patients who would benefit from limited axillary dissection. [ABSTRACT FROM AUTHOR]

Simple Summary: Glioblastoma is the most common malignant primary tumor of the central nervous system, with a poor prognosis despite many available treatments, including surgery, radiotherapy, and chemotherapy. The evaluation of treatment response is essential to optimize patient outcomes. While structural MRI remains the cornerstone of imaging evaluation, advanced MRI modalities have increasingly become crucial in characterizing treatment effects more comprehensively. The purpose of this pictorial essay is to provide an overview on the role of advanced MRI modalities at the different clinical-therapeutic timepoints, thus helping radiologists and clinicians to be more confident in their applicability in clinical practice and at the proper timepoint. MRI plays a key role in the evaluation of post-treatment changes, both in the immediate post-operative period and during follow-up. There are many different treatment's lines and many different neuroradiological findings according to the treatment chosen and the clinical timepoint at which MRI is performed. Structural MRI is often insufficient to correctly interpret and define treatment-related changes. For that, advanced MRI modalities, including perfusion and permeability imaging, diffusion tensor imaging, and magnetic resonance spectroscopy, are increasingly utilized in clinical practice to characterize treatment effects more comprehensively. This article aims to provide an overview of the role of advanced MRI modalities in the evaluation of treated glioblastomas. For a didactic purpose, we choose to divide the treatment history in three main timepoints: post-surgery, during Stupp (first-line treatment) and at recurrence (second-line treatment). For each, a brief introduction, a temporal subdivision (when useful) or a specific drug-related paragraph were provided. Finally, the current trends and application of radiomics and artificial intelligence (AI) in the evaluation of treated GB have been outlined. [ABSTRACT FROM AUTHOR]

BackgroundNoninvasive measurement of placental blood flow is the major technical challenge for predicting ischemic placenta (IPD). Pseudocontinuous arterial spin labeling (pCASL) MRI was recently shown to be promising, but the potential value in predicting the subsequence development of IPD is not known.PurposeTo derive global and regional placental blood flow parameters from longitudinal measurements of pCASL MRI and to assess the associations between perfusion-related parameters and IPD.Study typeProspective.PopulationEighty-four women completed two pCASL MRI scans (first; 14-18 weeks and second; 19-24 weeks) from prospectively recruited 118 subjects. A total of 69 subjects were included for the analysis, of which 15 subjects developed IPD.Field strength/sequence3T/T2 -weighted half-Fourier single-shot turbo spin-echo (HASTE) and pCASL.AssessmentFour perfusion-related parameters in the placenta were derived: placenta volume, placental blood flow (PBF), high PBF (hPBF), and relative hPBF. The longitudinal changes of the parameters and their association with IPD were tested after being normalizing to the 16th and 20th weeks of gestation.Statistical testsComparisons between two gestational ages within subjects were performed using the paired Wilcoxon tests, and comparisons between normal and IPD groups were performed using the unpaired Wilcoxon tests.ResultsThe difference between the first and second MRI scans was statistically significant for volume (156.6 cm3 vs. 269.7 cm3 , P

Predicting clinical outcomes after stroke, using magnetic resonance imaging (MRI) measures, remains a challenge. The purpose of this study was to investigate the prediction of long-term clinical outcomes after ischemic stroke using parametric response mapping (PRM) based on perfusion MRI data. Multiparametric perfusion MRI datasets from 30 patients with chronic ischemic stroke were acquired at four-time points ranging from V2 (6 weeks) to V5 (7 months) after stroke onset. All perfusion MR parameters were analyzed using the classic whole-lesion approach and voxel-based PRM at each time point. The imaging biomarkers from each acquired MRI metric that was predictive of both neurological and functional outcomes were prospectively investigated. For predicting clinical outcomes at V5, it was identified that PRMTmax-, PRMrCBV-, and PRMrCBV+ at V3 were superior to the mean values of the corresponding maps at V3. We identified correlations between the clinical prognosis after stroke and MRI parameters, emphasizing the superiority of the PRM over the whole-lesion approach for predicting longterm clinical outcomes. This indicates that complementary information for the predictive assessment of clinical outcomes can be obtained using PRM analysis. Moreover, new insights into the heterogeneity of stroke lesions revealed by PRM can help optimize the accurate stratification of patients with stroke and guide rehabilitation. [ABSTRACT FROM AUTHOR]

Background: Dynamic contrast‐enhanced MRI (DCE‐MRI) has seen increasing use for quantification of low level of blood–brain barrier (BBB) leakage in various pathological disease states and correlations with clinical outcomes. However, currently there exists limited studies on reproducibility in healthy controls, which is important for the establishment of a normality threshold for future research. Purpose: To investigate the reproducibility of DCE‐MRI and to evaluate the effect of arterial input function (AIF) selection and manual region of interests (ROI) delineation vs. automated global segmentation. Study Type: Prospective. Population: A total of 16 healthy controls; 11 females; mean age 28.7 years (SD 10.1). Field Strength/Sequence: A 3T; GE DCE; 3D TFE T1WI. 2D TSE T2. Assessment: The influx constant Ki, a measure of BBB permeability, and Vp, the blood plasma volume, was calculated using the Patlak model. Cerebral blood flow (CBF) was calculated using Tikhonov model free deconvolution. Manual tissue ROIs, drawn by H.J.S. (30+ years of experience), were compared to automatic tissue segmentation. Statistical Tests: Intraclass correlation coefficient (ICC) and repeatability coefficient (RC) was used to assess reproducibility. Bland–Altman plots were used to evaluate agreement between measurements day 1 vs. day 2, and manual vs. segmentation method. Results: Ki showed excellent reproducibility in both white and gray matter with an ICC between 0.79 and 0.82 and excellent agreement between manual ROI and automatic segmentation, with an ICC of 0.89 for Ki in WM. Furthermore, Ki values in gray and white matter conforms with histological tissue characteristics, where gray matter generally has a 2‐fold higher vessel density. The highest reproducibility measures of Ki (ICC = 0.83), CBF (ICC = 0.77) and Vd (ICC = 0.83) was obtained with the AIF sampled in the internal carotid artery (ICA). Data Conclusion: DCE‐MRI shows excellent reproducibility of pharmacokinetic variables derived from healthy controls. Evidence Level: 2 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background Collaterals are the main determinants of the severity of cerebral ischemia and control the pace of the ischemic tissue damage in acute ischemic stroke. Assessment of collateral status remains a major challenge in stroke imaging. We evaluated a signal variance–based collateral vessel index in perfusion‐weighted imaging (CVIPWI) in terms of its association with initial stroke severity, presence of a mismatch for endovascular thrombectomy (EVT), and early functional outcome in patients with large‐vessel occlusion. Methods T2*‐weighted time series from dynamic susceptibility contrast perfusion imaging were processed to calculate the CVIPWI. Ischemic cores were segmented automatically on apparent diffusion coefficient maps. The relationship between collateral status and the fulfilment of mismatch criteria for EVT as well as the association between the CVIPWI and functional outcome in patients undergoing EVT were analyzed. Furthermore, spatial patterns of pial collateralization were investigated. Results A total of 156 patients with large‐vessel occlusion were included in the final analysis. Higher CVIPWI and thus better collateral supply was associated with lower baseline National Institutes of Health Stroke Scale and smaller baseline infarct volumes (P=0.022 and P=0.002, respectively), and the CVIPWI varied significantly among groups according to fulfillment of mismatch criteria for EVT (P

Altered blood flow in the human brain is characteristic of typical aging. However, numerous factors contribute to inter-individual variation in patterns of blood flow throughout the lifespan. To better understand the mechanisms behind such variation, we studied how sex and APOE genotype, a primary genetic risk factor for Alzheimer's disease (AD), influence associations between age and brain perfusion measures. We conducted a cross-sectional study of 562 participants from the Human Connectome Project - Aging (36 to >90 years of age). We found widespread associations between age and vascular parameters, where increasing age was associated with regional decreases in cerebral blood flow (CBF) and increases in arterial transit time (ATT). When grouped by sex and APOE genotype, interactions between group and age demonstrated that females had relatively greater CBF and lower ATT compared to males. Females carrying the APOE ε4 allele showed the strongest association between CBF decline and ATT incline with age. This demonstrates that sex and genetic risk for AD modulate age-associated patterns of cerebral perfusion measures.

Predicting clinical outcomes after stroke, using magnetic resonance imaging (MRI) measures, remains a challenge. The purpose of this study was to investigate the prediction of long-term clinical outcomes after ischemic stroke using parametric response mapping (PRM) based on perfusion MRI data. Multiparametric perfusion MRI datasets from 30 patients with chronic ischemic stroke were acquired at four-time points ranging from V2 (6 weeks) to V5 (7 months) after stroke onset. All perfusion MR parameters were analyzed using the classic whole-lesion approach and voxel-based PRM at each time point. The imaging biomarkers from each acquired MRI metric that was predictive of both neurological and functional outcomes were prospectively investigated. For predicting clinical outcomes at V5, it was identified that PRMTmax-, PRMrCBV-, and PRMrCBV+ at V3 were superior to the mean values of the corresponding maps at V3. We identified correlations between the clinical prognosis after stroke and MRI parameters, emphasizing the superiority of the PRM over the whole-lesion approach for predicting long-term clinical outcomes. This indicates that complementary information for the predictive assessment of clinical outcomes can be obtained using PRM analysis. Moreover, new insights into the heterogeneity of stroke lesions revealed by PRM can help optimize the accurate stratification of patients with stroke and guide rehabilitation.

Alterations in cerebral perfusion is increasingly considered to play a crucial role in Alzheimer's disease (AD) and together with accumulated amyloid-β, deficiencies in the brain microvascular circulation may result in local hypoxia. Here, we studied alterations in cerebral circulation and the correlation between amyloid-β load and cerebral perfusion in prodromal AD (pAD). Using dynamic susceptibility contrast MRI and PET, we evaluated cerebral perfusion and amyloid-β levels in 19 individuals with mild cognitive impairment (MCI) and high amyloid-β load (pAD-MCI), 13 MCI individuals without AD pathology and 21 healthy controls. The pAD-MCI group showed significantly lower microvascular blood flow and significantly higher heterogeneity of microvascular blood transit times (p < 0.01) compared with the other 2 groups. Additionally, in the pAD-MCI group raised amyloid-β levels correlated with decreased microvascular blood flow and increased heterogeneity of microvascular blood flow in frontal and temporal areas (p < 0.01). These results indicate a close connection between levels of amyloid-β deposition and brain microvascular perfusion in pAD. A vicious cycle may be established where amyloid-β load and deficiencies in brain perfusion may reinforce each other. [ABSTRACT FROM AUTHOR]

Cognitive impairment (CI) is a major health concern in aging populations. It impairs patients' independent life and may progress to dementia. Vascular cognitive impairment (VCI) encompasses all cerebrovascular pathologies that contribute to cognitive impairment (CI). Moreover, the majority of CI subtypes involve various aspects of vascular dysfunction. Recent research highlights the critical role of reduced cerebral blood flow (CBF) in the progress of VCI, and the detection of altered CBF may help to detect or even predict the onset of VCI. Arterial spin labeling (ASL) is a non-invasive, non-ionizing perfusion MRI technique for assessing CBF qualitatively and quantitatively. Recent methodological advances enabling improved signal-to-noise ratio (SNR) and data acquisition have led to an increase in the use of ASL to assess CBF in VCI patients. Combined with other imaging modalities and biomarkers, ASL has great potential for identifying early VCI and guiding prediction and prevention strategies. This review focuses on recent advances in ASL-based perfusion MRI for identifying patients at high risk of VCI. [ABSTRACT FROM AUTHOR]

Background: A typical stroke MRI protocol includes perfusion‐weighted imaging (PWI) and MR angiography (MRA), requiring a second dose of contrast agent. A deep learning method to acquire both PWI and MRA with single dose can resolve this issue. Purpose: To acquire both PWI and MRA simultaneously using deep learning approaches. Study type: Retrospective. Subjects: A total of 60 patients (30–73 years old, 31 females) with ischemic symptoms due to occlusion or ≥50% stenosis (measured relative to proximal artery diameter) of the internal carotid artery, middle cerebral artery, or anterior cerebral artery. The 51/1/8 patient data were used as training/validation/test. Field Strength/Sequence: A 3 T, time‐resolved angiography with stochastic trajectory (contrast‐enhanced MRA) and echo planar imaging (dynamic susceptibility contrast MRI, DSC‐MRI). Assessment: We investigated eight different U‐Net architectures with different encoder/decoder sizes and with/without an adversarial network to generate perfusion maps from contrast‐enhanced MRA. Relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), mean transit time (MTT), and time‐to‐max (Tmax) were mapped from DSC‐MRI and used as ground truth to train the networks and to generate the perfusion maps from the contrast‐enhanced MRA input. Statistical Tests: Normalized root mean square error, structural similarity (SSIM), peak signal‐to‐noise ratio (pSNR), DICE, and FID scores were calculated between the perfusion maps from DSC‐MRI and contrast‐enhanced MRA. One‐tailed t‐test was performed to check the significance of the improvements between networks. P values < 0.05 were considered significant. Results: The four perfusion maps were successfully extracted using the deep learning networks. U‐net with multiple decoders and enhanced encoders showed the best performance (pSNR 24.7 ± 3.2 and SSIM 0.89 ± 0.08 for rCBV). DICE score in hypo‐perfused area showed strong agreement between the generated perfusion maps and the ground truth (highest DICE: 0.95 ± 0.04). Data Conclusion: With the proposed approach, dynamic angiography MRI may provide vessel architecture and perfusion‐relevant parameters simultaneously from a single scan. Evidence Level: 3 Technical Efficacy: Stage 5 [ABSTRACT FROM AUTHOR]

MRI is undoubtedly the cornerstone of brain tumor imaging, playing a key role in all phases of patient management, starting from diagnosis, through therapy planning, to treatment response and/or recurrence assessment. Currently, neuroimaging can describe morphologic and non-morphologic (functional, hemodynamic, metabolic, cellular, microstructural, and sometimes even genetic) characteristics of brain tumors, greatly contributing to diagnosis and follow-up. Knowing the technical aspects, strength and limits of each MR technique is crucial to correctly interpret MR brain studies and to address clinicians to the best treatment strategy. This article aimed to provide an overview of neuroimaging in the assessment of adult primary brain tumors. We started from the basilar role of conventional/morphological MR sequences, then analyzed, one by one, the non-morphological techniques, and finally highlighted future perspectives, such as radiomics and artificial intelligence. [ABSTRACT FROM AUTHOR]

Apathy, as defined as a deficit in goal-directed behaviors, is a critical clinical dimension in depression associated with chronic impairment. Little is known about its cerebral perfusion specificities in depression. To explore neurovascular mechanisms underpinning apathy in depression by pseudo-continuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI). Perfusion imaging analysis was performed on 90 depressed patients included in a prospective study between November 2014 and February 2017. Imaging data included anatomical 3D T1-weighted and perfusion pCASL sequences. A multiple regression analysis relating the quantified cerebral blood flow (CBF) in different regions of interest defined from the FreeSurfer atlas, to the Apathy Evaluation Scale (AES) total score was conducted. After confound adjustment (demographics, disease and clinical characteristics) and correction for multiple comparisons, we observed a strong negative relationship between the CBF in the left anterior cingulate cortex (ACC) and the AES score (standardized beta = −0.74, corrected p value = 0.0008). Our results emphasized the left ACC as a key region involved in apathy severity in a population of depressed participants. Perfusion correlates of apathy in depression evidenced in this study may contribute to characterize different phenotypes of depression. • An MRI perfusion ASL study of apathy in depression. • In this sample of depressed patients apathy related to brain regional perfusion. • A negative relationship between the left ACC CBF and the AES score was significant. • Biological characterization of apathy could help phenotyping subtypes of depression. • A step forward understanding motivation in depression and its treatment. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to evaluate the impact of eyes‐closed resting and eyes‐open conditions on the measurement of cerebral blood flow (CBF) using arterial spin labeling magnetic resonance imaging (ASL MRI). Methods: Thirty healthy volunteers underwent 3.0‐T MRI scans under two conditions—eyes‐closed resting and eyes‐open (stationary state)—1 week apart. CBF was measured using an asymmetric inversion slab technique with a three‐dimensional fast field echo sequence, which is a pulsed ASL technique, in the temporal lobe, precentral gyrus, limbic lobe, occipital lobe, and parietal lobe. Results: CBF was not significantly different under eyes‐closed resting and eyes‐open states in the temporal lobe, precentral gyrus, limbic lobe, and parietal lobe. However, the CBF values of the occipital lobe were significantly lower under the eyes‐closed resting condition than under the eyes‐open condition. The means and standard deviations of CBF in the occipital lobe were 62.3 ± 7.9 ml/100 g/min for eyes‐open and 56.9 ± 7.9 ml/100 g/min for eyes‐closed resting. CBF obtained under eyes‐closed resting and eyes‐open conditions showed good reproducibility. In addition, the reproducibility and CBF measurement error were improved by excluding the occipital lobe. Conclusions: The eyes‐closed resting condition affects the CBF measurement obtained by ASL MRI, particularly in the occipital lobe. To improve the measurement accuracy of ASL, measurements should be performed under the eyes‐closed resting condition in the clinical setting. [ABSTRACT FROM AUTHOR]

Abstract This retrospective and exploratory study investigated the efficiency of the 3T perfusion magnetic resonance imaging (MRI) at the classification of MS lesion subtypes. For the MS lesion subtype classification, firstly, it was necessary to segment all MS lesions. Therefore, a Bayesian classifier based on the adaptive mixture method was used to segment all lesions, and an artificial neural network (ANN) employed a multi‐layer Perceptron as a subtype classifier. The Bayesian classifier accomplished the segmentation of lesions using Fluid Attenuated Inversion Recovery automatically, and the ANN part was used as a subtype classifier that worked based on extracted information from perfusion MRI (i.e. Mean Transit Time and Cerebral Blood Volume maps) along with the intensity information of the conventional multi‐channel MRI in segmented lesions. Adding 3‐Tesla perfusion MRI to the proposed model for the subtype classification led to an increment of about 7% and 13% in the sensitivity of acute and chronic lesion classifications, respectively. The sensitivity of T2 lesions did not meaningfully change. The overall accuracy of the classification for acute, chronic, and T2 lesion classifications was 96.1%, 90.5%, and 92.9%, respectively. The proposed architectures reached high sensitivity in discrimination between MS lesion subtypes when 3T perfusion MRIs were used.

The human brain undergoes rapid changes from the fetal stage to two years postnatally, during which proper structural and functional maturation lays the foundation for later cognitive and behavioral development. Multimodal magnetic resonance imaging (MRI) techniques, especially structural MRI (sMRI), diffusion MRI (dMRI), functional MRI (fMRI), and perfusion MRI (pMRI), provide unprecedented opportunities to non-invasively quantify these early brain changes at whole brain and regional levels. Each modality offers unique insights into the complex processes of both typical neurodevelopment and the pathological mechanisms underlying psychiatric and neurological disorders. Compared to a single modality, multimodal MRI enhances discriminative power and provides more comprehensive insights for understanding and improving neurodevelopmental and mental health outcomes, particularly in high-risk populations. Machine learning- and deep learning-based methods have demonstrated significant potential for predicting future outcomes using multimodal brain MRI acquired during early childhood. Here, we review the unique characteristics of various MRI techniques for imaging early brain development and describe the common approaches to analyze these modalities. We then discuss machine learning approaches in predicting future neurodevelopmental and clinical outcomes using multimodal MRI information during early childhood, highlighting the potential of identifying biomarkers for early detection and personalized interventions in atypical development. [ABSTRACT FROM AUTHOR]

Our study aims to reveal clinically helpful prognostic markers using quantitative radiologic data from perfusion magnetic resonance imaging for patients with locally advanced carcinoma, using the Ki-67 index as a surrogate. Patients who received a breast cancer diagnosis and had undergone dynamic contrast-enhanced magnetic resonance imaging of the breast for pretreatment evaluation and follow-up were searched retrospectively. We evaluated the MRI studies for perfusion parameters and various categories and compared them to the Ki-67 index. Axillary involvement was categorized as low (N0–N1) or high (N2–N3) according to clinical stage. A total sum of 60 patients’ data was included in this study. Perfusion parameters and Ki-67 showed a significant correlation with the transfer constant (Ktrans) (ρ = 0.554 p = 0.00), reverse transfer constant (Kep) (ρ = 0.454 p = 0.00), and initial area under the gadolinium curve (IAUGC) (ρ = 0.619 p = 0.00). The IAUGC was also significantly different between axillary stage groups (Z = 2.478 p = 0.013). Outside of our primary hypothesis, associations between axillary stage and contrast enhancement (x2 = 8.023 p = 0.046) and filling patterns (x2 = 8.751 p = 0.013) were detected. In conclusion, these parameters are potential prognostic markers in patients with moderate Ki-67 indices, such as those in our study group. The relationship between axillary status and perfusion parameters also has the potential to determine patients who would benefit from limited axillary dissection.

INTRODUCTION: Carotid revascularisation improves haemodynamic compromise in cerebral circulation as an additional benefit to the primary goal of reducing future thromboembolic risk. We determined the effect of carotid artery stenting on cerebral perfusion and oxygenation using a perfusion-weighted MRI algorithm that is based on assessment of capillary transit-time heterogeneity together with other perfusion and metabolism-related metrics. PATIENTS AND METHODS: A consecutive series of 33 patients were evaluated by dynamic susceptibility contrast perfusion-weighted MRI prior to and within 24 h of the endovascular procedure. The level of relative change induced by stenting, and relationship of these changes with respect to baseline stenosis degree were analysed. RESULTS: Stenting led to significant increase in cerebral blood flow (p  2s decreased from 24 ml to 12 ml (p = 0.009), with CTH > 2s from 29 ml to 19 ml (p = 0.041), and with RTH

Simple Summary: Pediatric brain tumors are the second most common type of childhood cancer and the leading cause of cancer death in children. Many survivors have long-term cognitive impairments and behavioral issues as a result of treatment, which may reduce their quality of life. Magnetic resonance imaging (MRI) techniques have revealed structural and functional brain changes that may be related to clinically observed cognitive impairment. A special emphasis has been placed on arterial spin labeling (ASL) MRI, which can be used to estimate changes in capillary perfusion after radiotherapy, in order to assess treatment response and neurocognitive sequelae. The current review was conducted to knowledge of ASL techniques and describe the main findings of research on the use of ASL in both healthy pediatric populations and patients treated for brain tumors. Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique for measuring cerebral blood flow (CBF). This noninvasive technique has added a new dimension to the study of several pediatric tumors before, during, and after treatment, be it surgery, radiotherapy, or chemotherapy. However, ASL has three drawbacks, namely, a low signal-to-noise-ratio, a minimum acquisition time of 3 min, and limited spatial summarize current resolution. This technique requires quality control before ASL-CBF maps can be extracted and before any clinical investigations can be conducted. In this review, we describe ASL perfusion principles and techniques, summarize the most recent advances in CBF quantification, report technical advances in ASL (resting-state fMRI ASL, BOLD fMRI coupled with ASL), set out guidelines for ASL quality control, and describe studies related to ASL-CBF perfusion and qualitative and semi-quantitative ASL weighted-map quantification, in healthy children and those with pediatric brain tumors. [ABSTRACT FROM AUTHOR]

Purpose: Multiple burr hole surgery is considered to be an option for achieving indirect revascularization in patients with ischemic Moyamoya disease (MMD). We aimed to investigate the efficacy of stand-alone multiple burr hole surgery for salvage revascularization in patients with MMD by assessing the hemodynamic changes via normalized time-to-peak (nTTP) analysis and independent component analysis (ICA) of preoperative and postoperative dynamic susceptibility contrast (DSC) perfusion MRI data. Methods: The DSC perfusion MRI data of 25 hemispheres from 21 patients with MMD, who underwent multiple burr hole surgery for salvage revascularization due to persistent or recurrent symptoms after primary revascularization with modified encephaloduroarteriosynangiosis (mEDAS), were analyzed. The nTTP, which was measured using the region of interests covering the entire surgical hemisphere, was compared between the preoperative and postoperative images. ICA was used to compare the relative arterial and venous components of the surgical hemispheres between the respective preoperative and postoperative images. Results: The median postoperative nTTP (1.80 s) was significantly shorter than the median preoperative nTTP (4.10 s) (P < 0.001). The postoperative relative arterial component of the surgical hemisphere (median: 0.04) was significantly higher than the preoperative relative arterial component (median: − 0.02, P < 0.001). In contrast, the postoperative relative venous component of the surgical hemisphere (median: − 0.05) was significantly lower than the preoperative value (median: 0.05, P < 0.001). Conclusion: The improvement in cerebral perfusion parameters observed on postoperative DSC perfusion MRI demonstrated that stand-alone multiple burr hole surgery could be a favorable salvage revascularization technique after mEDAS failure in patients with ischemic MMD. [ABSTRACT FROM AUTHOR]

Neuroimaging plays an ever evolving role in the diagnosis, treatment planning, and post-therapy assessment of brain tumors. This review provides an overview of current magnetic resonance imaging (MRI) methods routinely employed in the care of the brain tumor patient. Specifically, we focus on advanced techniques including diffusion, perfusion, spectroscopy, tractography, and functional MRI as they pertain to noninvasive characterization of brain tumors and pretreatment evaluation. The utility of both structural and physiological MRI in the post-therapeutic brain evaluation is also reviewed with special attention to the challenges presented by pseudoprogression and pseudoresponse.

The value of perfusion and diffusion-weighted MRI in differentiating histological subtypes according to the 2007 WHO glioma classification scheme (i.e. astrocytoma vs. oligodendroglioma) and genetic subtypes according to the 2016 WHO reclassification (e.g. 1p/19q co-deletion and IDH1 mutation status) in WHO grade II and III diffuse gliomas remains controversial. In the current study, we describe unique perfusion and diffusion MR signatures between histological and genetic glioma subtypes. Sixty-five patients with 2007 histological designations (astrocytomas and oligodendrogliomas), 1p/19q status (+ = intact/- = co-deleted), and IDH1 mutation status (MUT/WT) were included in this study. In all patients, median relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) were estimated within T2 hyperintense lesions. Bootstrap hypothesis testing was used to compare subpopulations of gliomas, separated by WHO grade and 2007 or 2016 glioma classification schemes. A multivariable logistic regression model was also used to differentiate between 1p19q+ and 1p19q- WHO II-III gliomas. Neither rCBV nor ADC differed significantly between histological subtypes of pure astrocytomas and pure oligodendrogliomas. ADC was significantly different between molecular subtypes (p = 0.0016), particularly between IDHWT and IDHMUT/1p19q+ (p = 0.0013). IDHMUT/1p19q+ grade III gliomas had higher median ADC; IDHWT grade III gliomas had higher rCBV with lower ADC; and IDHMUT/1p19q- had intermediate rCBV and ADC values, similar to their grade II counterparts. A multivariable logistic regression model was able to differentiate between IDHWT and IDHMUT WHO II and III gliomas with an AUC of 0.84 (p

(1) Background: This work characterizes the sensitivity of magnetic resonance-based Relaxivity Contrast Imaging (RCI) to Amyotrophic Lateral Sclerosis (ALS)-induced changes in myofiber microstructure. Transverse Relaxivity at Tracer Equilibrium (TRATE), an RCI-based parameter, was evaluated in the lower extremities of ALS patients and healthy subjects. (2) Methods: In this IRB-approved study, 23 subjects (12 ALS patients and 11 healthy controls) were scanned at 3T (Philips, The Netherlands). RCI data were obtained during injection of a gadolinium-based contrast agent. TRATE, fat fraction and T2 measures, were compared in five muscle groups of the calf muscle, between ALS and control populations. TRATE was also evaluated longitudinally (baseline and 6 months) and was compared to clinical measures, namely ALS Functional Rating Scale (ALSFRS-R) and Hand-Held Dynamometry (HHD), in a subset of the ALS population. (3) Results: TRATE was significantly lower (p < 0.001) in ALS-affected muscle than in healthy muscle in all muscle groups. Fat fraction differences between ALS and healthy muscle were statistically significant for the tibialis anterior (p = 0.01), tibialis posterior (p = 0.004), and peroneus longus (p = 0.02) muscle groups but were not statistically significant for the medial (p = 0.07) and lateral gastrocnemius (p = 0.06) muscles. T2 differences between ALS and healthy muscle were statistically significant for the tibialis anterior (p = 0.004), peroneus longus (p = 0.004) and lateral gastrocnemius (p = 0.03) muscle groups but were not statistically significant for the tibialis posterior (p = 0.06) and medial gastrocnemius (p = 0.07) muscles. Longitudinally, TRATE, averaged over all patients, decreased by 28 ± 16% in the tibialis anterior, 47 ± 18% in the peroneus longus, 25 ± 19% in the tibialis posterior, 29 ± 14% in the medial gastrocnemius and 35 ± 18% in the lateral gastrocnemius muscles between two timepoints. ALSFRS-R scores were stable in two of four ALS patients. HHD scores decreased in three of four ALS patients. (4) Conclusion: RCI-based TRATE was shown to consistently differentiate ALS-affected muscle from healthy muscle and also provide a quantitative measure of longitudinal muscle degeneration.

• Harmonizing imaging practices will allow for well-informed decisions in oncology. • Imaging technology impacts surgical approaches and will shape future treatments. • 4D MRI can assess diaphragm function in the presence of malignant pleural effusion. • AI may predict outcome and aid treatment selection to improve precision oncology. • Perfusion MRI will benefit from automated reporting for early contrast enhancement. • Dedicated evaluation criteria for peritoneal metastases will aid drug development. Imaging continues to gain a greater role in the assessment and clinical management of patients with mesothelioma. This communication summarizes the oral presentations from the imaging session at the 2023 International Conference of the International Mesothelioma Interest Group (iMig), which was held in Lille, France from June 26 to 28, 2023. Topics at this session included an overview of best practices for clinical imaging of mesothelioma as reported by an iMig consensus panel, emerging imaging techniques for surgical planning, radiologic assessment of malignant pleural effusion, a radiomics-based transfer learning model to predict patient response to treatment, automated assessment of early contrast enhancement, and tumor thickness for response assessment in peritoneal mesothelioma. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the feasibility of using two novel agents, hyperpolarized [13C]t-butanol and [13C,15N2]urea, for assessing in vivo perfusion of the intact spinal cord in rodents. Due to their distinct permeabilities to blood brain barrier (BBB), we hypothesized that [13C]t-butanol and [13C,15N2]urea exhibit unique 13C signal characteristics in the spinal cord. Procedures: Dynamic 13C t-butanol MRI data were acquired from healthy Long-Evans rats using a symmetric, ramp-sampled, partial-Fourier 13C echo-planar imaging sequence after the injection of hyperpolarized [13C]t-butanol solution. In subsequent scans, dynamic 13C urea MRI data were acquired after the injection of hyperpolarized [13C,15N2]urea. The SNRs of t-butanol and urea were calculated for regions corresponding to spine, supratentorial brain, and blood vessels and plotted over time. Mean peak SNR and AUC were calculated from the dynamic plots for each region and compared between t-butanol and urea. Results: In spine and supratentorial brain, the mean peak SNR and AUC of t-butanol were significantly higher than those of urea (p < 0.05). In contrast, urea was predominantly contained within vasculature and exhibited significantly higher levels of mean peak SNR and AUC compared to t-butanol in blood vessels (p < 0.05). Conclusion: This study has demonstrated the feasibility of using hyperpolarized [13C]t-butanol and [13C,15N2]urea for assessing in vivo perfusion in cervical spinal cord. Due to differences in blood–brain barrier permeability, t-butanol rapidly crossed the blood–brain barrier and diffused into spine and brain tissue, while urea predominantly remained in vasculature. The results from this study suggest that this technique may provide unique non-invasive imaging tracers that are able to directly monitor hemodynamic processes in the normal and injured spinal cord. [ABSTRACT FROM AUTHOR]

This retrospective and exploratory study investigated the efficiency of the 3T perfusion magnetic resonance imaging (MRI) at the classification of MS lesion subtypes. For the MS lesion subtype classification, firstly, it was necessary to segment all MS lesions. Therefore, a Bayesian classifier based on the adaptive mixture method was used to segment all lesions, and an artificial neural network (ANN) employed a multi‐layer Perceptron as a subtype classifier. The Bayesian classifier accomplished the segmentation of lesions using Fluid Attenuated Inversion Recovery automatically, and the ANN part was used as a subtype classifier that worked based on extracted information from perfusion MRI (i.e. Mean Transit Time and Cerebral Blood Volume maps) along with the intensity information of the conventional multi‐channel MRI in segmented lesions. Adding 3‐Tesla perfusion MRI to the proposed model for the subtype classification led to an increment of about 7% and 13% in the sensitivity of acute and chronic lesion classifications, respectively. The sensitivity of T2 lesions did not meaningfully change. The overall accuracy of the classification for acute, chronic, and T2 lesion classifications was 96.1%, 90.5%, and 92.9%, respectively. The proposed architectures reached high sensitivity in discrimination between MS lesion subtypes when 3T perfusion MRIs were used. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to compare arterial spin labeling (ASL) with dynamic susceptibility contrast (DSC) enhanced perfusion MRI for the surveillance of primary and metastatic brain tumors at 3T, both in terms of lesion perfusion metrics and diagnostic accuracy. Methods: In this retrospective study, we included 115 patients, who underwent both ASL and DSC perfusion in the same 3T MRI scanning session between 1 January and 31 December 2019. ASL-derived cerebral blood flow (CBF) maps and DSC-derived relative cerebral blood volume (rCBV) maps, both uncorrected and corrected for leakage, were created with commercially available software. Lesions were identified as T2-/T2-FLAIR hyperintensity with or without contrast enhancement. Measurements were done by placing a region of interest in the visually determined area of highest perfusion, copying to the contralateral normal appearing white matter (NAWM), and then propagating to the other perfusion maps. Pearson's correlation coefficients were calculated between the CBF and rCBV ratios of tumor versus NAWM. Accuracy for diagnosing tumor progression was calculated as the area under the receiver operating characteristics (ROC) curve (AUC) for the ASL-CBF and leakage corrected DSC-rCBV ratios. Results: We identified 178 lesions, 119 with and 59 without contrast enhancement. Correlation coefficients between ASL-derived CBF versus DSC-derived rCBV ratios were 0.60–0.67 without and 0.72–0.78 with leakage correction in all lesions (n = 178); these were 0.65–0.80 in enhancing glioma (n = 80), 0.58–0.73 in non-enhancing glioma, and 0.14–0.40 in enhancing metastasis (n = 31). No significant correlation was found in enhancing (n = 8) or non-enhancing (n = 7) lymphomas. The areas under the ROC curves (AUCs) for all patients were similar for ASL and DSC (0.73–0.78), and were higher for enhancing glioma (AUC = 0.78–0.80) than for non-enhancing glioma (AUC = 0.56–0.62). In brain metastasis, the AUC was lower for ASL-derived CBF (AUC = 0.72) than for DSC-derived rCBV ratios (AUC = 0.87–0.93). Conclusion: We found that ASL and DSC have more or less the same diagnostic accuracy. Our findings suggest that ASL can be used as an alternative to DSC to measure perfusion in enhancing and non-enhancing gliomas and brain metastasis at 3T. For lymphoma, this should be further investigated in a larger population. [ABSTRACT FROM AUTHOR]

Context: Cerebral blood flow (CBF) measurement using arterial spin labelling (ASL) MRI sequences has recently emerged as a prominent tool in dementia research. Aims: To establish association between quantified regional cerebral perfusion and gray matter (GM) volumes with cognitive measures in mild cognitive impairment (MCI) and early Alzheimer's Dementia (AD), using three dimensional fast spin echo pseudo-continuous ASL MRI sequences. Settings and Design: Hospital-based cross-sectional study. Methods and Material: Three age-matched groups, i.e., 21 cognitively normal healthy controls (HC), 20 MCI and 19 early AD patients diagnosed using neuropsychological tests and who consented for multimodality 3T MRI were recruited for the study. Statistical Analysis Used: Statistical parametric mapping and regions of interest (ROI) multivariate analysis of variance was used to ascertain differences between patients and controls on MRI-volumetry and ASL. Linear regression was used to assess relationship between CBF with GM atrophy and neuropsychological test measures. Results: Compared to HC, patients with MCI and AD had significantly lower quantified perfusion in posterior cingulate and lingual gyri, over hippocampus in MCI, with no differences noted between MCI and AD. Atrophy over the middle temporal gyrus and hippocampus differentiated AD from MCI. No significant positive correlations were noted between perfusion and GM volumes in ROI with the exception of temporal neocortex. Significantly positive coefficient b-value (p < 0.01) were apparent between global cognition with CBF in precuneus, temporal neocortex and precuneus volume, with negative b-values noted between medial temporal CBF for global cognition and recall scores. Conclusions: ROI-based CBF measurements differentiated MCI and AD from HC; volumetry of medial and neocortical temporal GM separates AD from MCI. Correlations between CBF and neuropsychology are variable and require further longitudinal studies to gauge its predictive utility on cognitive trajectory in MCI.