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Background and purposeDifferential Subsampling with Cartesian Ordering (DISCO), an ultrafast high-spatial-resolution head MRA, has been introduced. We aimed to determine the diagnostic performance of DISCO-MRA in grading residual aneurysm in comparison with TOF-MRA in patients with treated intracranial aneurysms.Materials and methodsPatients with endovascular treatment and having undergone DISCO-MRA, TOF-MRA, and DSA were included for review. The voxel size and acquisition time were 0.75 × 0.75 × 1 mm3/6 seconds for DISCO-MRA and 0.6 × 0.6 × 1 mm3/6 minutes for TOF-MRA. Residual aneurysms were determined using the Modified Raymond-Roy Classification on TOF-MRA and DISCO-MRA by 2 neuroradiologists independently and were compared against DSA as the reference standard. Statistical analysis was performed using the κ statistic and the χ2 test.ResultsSixty-eight treated intracranial aneurysms were included. The intermodality agreement was κ = 0.82 (95% CI, 0.67-0.97) between DISCO and DSA and 0.44 (95% CI, 0.28-0.61) between TOF and DSA. Modified Raymond-Roy Classification scores matched DSA scores in 60/68 cases (88%; χ2 = 144.4, P < .001 for DISCO and 46/68 cases (68%; χ2 = 65.0, P < .001) for TOF. The diagnostic accuracy for the detection of aneurysm remnants was higher for DISCO (0.96; 95% CI, 0.88-0.99) than for TOF (0.79; 95% CI, 0.68-0.88).ConclusionsIn patients with endovascularly treated intracranial aneurysms, DISCO-MRA provides superior diagnostic performance in comparison with TOF-MRA in delineating residual aneurysms in a fraction of the time.

Background and purposeTwo-thirds of lymphatic malformations in children are found in the head and neck. Although conventionally managed through surgical resection, percutaneous sclerotherapy has gained popularity. No reproducible grading system has been designed to compare sclerotherapy outcomes on the basis of radiologic findings. We propose an MR imaging-based grading scale to assess the response to sclerotherapy and present an evaluation of its interrater reliability.Materials and methodsA grading system was developed to stratify treatment outcomes on the basis of interval changes observed on MR imaging. By means of this system, 56 consecutive cases from our institution with formally diagnosed head and neck lymphatic malformations treated by sclerotherapy were retrospectively graded. Each patient underwent pre- and posttreatment MR imaging. Each study was evaluated by 3 experienced neuroradiologists. Interrater reliability was assessed using the Krippendorff α statistic, intraclass coefficient, and 2-way Spearman ρ correlation.ResultsThe overall Krippendorff α statistic was 0.93 (95% CI, 0.89-0.95), denoting excellent agreement among raters. Intraclass coefficients with respect to consistency and absolute agreements were both 0.97 (95% CI, 0.96-0.98), illustrating low variability. Every combination of individual rater pairs demonstrated statistically significant (P < .01) linear Spearman ρ correlations, with values ranging from 0.90 to 0.95.ConclusionsThe proposed radiographic grading scale demonstrates excellent interrater reliability. Adoption of this new scale can standardize reported outcomes following sclerotherapy for head and neck lymphatic malformation and may aid in the investigation of future questions regarding optimal management of these lesions.

Background and purposeDeveloped using a rigorous mathematic framework, Maximum AmbiGuity distance for Phase Imaging (MAGPI) is a promising phase-imaging technique that provides optimal phase SNR and reduced susceptibility artifacts. We aimed to test the potential of MAGPI over routinely used SWI in the detection of traumatic cerebral microbleeds in athletes diagnosed with mild traumatic brain injury.Materials and methodsIn this prospective study, 10 athletes (18-22 years of age, 3 women/7 men) diagnosed with mild traumatic brain injury were enrolled. Brain MRIs were performed using 3T MR imaging at 2 days, 2 weeks, and 2 months after head trauma. The imaging protocol included whole-brain T1 MPRAGE, T2 FLAIR, conventional SWI, and the MAGPI multiecho sequence. Phase images from MAGPI were put through a previously described SWI process to generate MAGPI-SWI. Conventional and MAGPI-SWI were assessed independently by a board-certified neuroradiologist for the presence of contusions and cerebral microbleeds. All participants had routine neuropsychological assessment and Visuo-Motor Tests.ResultsAt initial assessment, 4 of the participants had visuo-motor performance indicative of mild traumatic brain injury, and 4 participants had a Post-Concussion Symptom Scale score of >21, a threshold that has been used to define moderate impairment. Cerebral microbleeds were identified in 6 participants on MAGPI-SWI, 4 of whom had evidence of concurrent contusions on FLAIR imaging. None of these cerebral microbleeds were identified confidently on conventional SWI due to substantial distortion and susceptibility artifacts.ConclusionsOptimal phase unwrapping with reduced susceptibility in MAGPI-SWI can clarify small microbleeds that can go undetected with routinely used conventional SWI.

Cerebral amyloid angiopathy is characterized by deposition of amyloid-β fibrils in the walls of small-to-medium-sized blood vessels. In this retrospective review of 5 patients with histologically confirmed noninflammatory cerebral amyloid angiopathy, high-resolution vessel wall MRI showed arterial wall enhancement in 2 patients (40%). Despite common consensus of equating vessel wall enhancement with inflammation, this report demonstrates that β-amyloid accumulation alone without inflammation can be associated with arterial wall enhancement in a subset of patients.

Background and purposeOur aim was to test the hypothesis that our recently introduced 4D-dynamic contrast-enhanced MR imaging with high spatial and temporal resolution has equivalent accuracy to 4D-CT for preoperative gland localization in primary hyperparathyroidism without requiring exposure to ionizing radiation.Materials and methodsInclusion criteria were the following: 1) confirmed biochemical diagnosis of primary hyperparathyroidism, 2) preoperative 4D-dynamic contrast-enhanced MR imaging, and 3) surgical cure with >50% decrease in serum parathyroid hormone intraoperatively. 4D-dynamic contrast-enhanced studies were reviewed independently by 2 neuroradiologists to identify the side, quadrant, and number of abnormal glands, and compared with surgical and pathologic results.ResultsFifty-four patients met the inclusion criteria: 37 had single-gland disease, and 17, multigland disease (9 with double-gland hyperplasia; 3 with 3-gland hyperplasia; and 5 with 4-gland hyperplasia). Interobserver agreement (κ) for the side (right versus left) was 0.92 for single-gland disease and 0.70 for multigland disease. Interobserver agreement for the quadrant (superior versus inferior) was 0.70 for single-gland disease and 0.69 for multigland disease. For single-gland disease, the gland was correctly located in 34/37 (92%) patients, with correct identification of the side in 37/37 (100%) and the quadrant in 34/37 (92%) patients. For multigland disease, the glands were correctly located in 35/47 (74%) patients, with correct identification of the side in 35/47 (74%) and the quadrant in 36/47 (77%).ConclusionsThe proposed high spatial and temporal resolution 4D-dynamic contrast-enhanced MR imaging provides excellent diagnostic performance for preoperative localization in primary hyperparathyroidism, with correct gland localization of 92% for single-gland disease and 74% in multigland disease, superior to 4D-CT studies.

Background and purposeDSC perfusion has been increasingly used in conjunction with other contrast-enhanced MR applications and therefore there is need for contrast-dose reduction when feasible. The purpose of this study was to establish the feasibility of reduced-contrast-dose brain DSC perfusion by using a probabilistic Bayesian method and to compare the results with the commonly used singular value decomposition technique.Materials and methodsHalf-dose (0.05-mmol/kg) and full-dose (0.1-mmol/kg) DSC perfusion studies were prospectively performed in 20 patients (12 men; 34-70 years of age) by using a 3T MR imaging scanner and a gradient-EPI sequence (TR/TE, 1450/22 ms; flip angle, 90°). All DSC scans were processed with block circulant singular value decomposition and Bayesian probabilistic methods. SNR analysis was performed in both half-dose and full-dose groups. The CBF, CBV, and MTT maps from both full-dose and half-dose scans were evaluated qualitatively and quantitatively in both WM and GM on coregistered perfusion maps. Statistical analysis was performed by using a t test, regression, and Bland-Altman analysis.ResultsThe SNR was significantly (P < .0001) lower in the half-dose group with 32% and 40% reduction in GM and WM, respectively. In the half-dose group, the image-quality scores were significantly higher in Bayesian-derived CBV (P = .02) and MTT (P = .004) maps in comparison with block circulant singular value decomposition. Quantitative values of CBF, CBV, and MTT in Bayesian-processed data were comparable and without a statistically significant difference between the half-dose and full-dose groups. The block circulant singular value decomposition-derived half-dose perfusion values were significantly different from those of the full-dose group both in GM (CBF, P < .001; CBV, P = .02; MTT, P = .02) and WM (CBF, P < .001; CBV, P = .003; MTT, P = .01).ConclusionsReduced-contrast-dose (0.05-mmol/kg) DSC perfusion of the brain is feasible at 3T by using the Bayesian probabilistic method with quantitative results comparable with those of the full-dose protocol.

Background and purposeThere is need to improve image acquisition speed for MR imaging in evaluation of patients with acute ischemic stroke. The purpose of this study was to evaluate the feasibility of a 3T MR stroke protocol that combines low-dose contrast-enhanced MRA and dynamic susceptibility contrast perfusion, without additional contrast.MethodsThirty patients with acute stroke who underwent 3T MR imaging followed by DSA were retrospectively enrolled. TOF-MRA of the neck and brain and 3D contrast-enhanced MRA of the craniocervical arteries were obtained. A total of 0.1 mmol/kg of gadolinium was used for both contrast-enhanced MRA (0.05 mmol/kg) and dynamic susceptibility contrast perfusion (0.05 mmol/kg) (referred to as half-dose). An age-matched control stroke population underwent TOF-MRA and full-dose (0.1 mmol/kg) dynamic susceptibility contrast perfusion. The cervicocranial arteries were divided into 25 segments. Degree of arterial stenosis on contrast-enhanced MRA and TOF-MRA was compared with DSA. Time-to-maximum maps (>6 seconds) were evaluated for image quality and hypoperfusion. Quantitative analysis of arterial input function curves, SNR, and maximum T2* effects were compared between half- and full-dose groups.ResultsThe intermodality agreements (k) for arterial stenosis were 0.89 for DSA/contrast-enhanced MRA and 0.63 for DSA/TOF-MRA. Detection specificity of >50% arterial stenosis was lower for TOF-MRA (89%) versus contrast-enhanced MRA (97%) as the result of overestimation of 10% (39/410) of segments by TOF-MRA. The DWI-perfusion mismatch was identified in both groups with high interobserver agreement (r = 1). There was no significant difference between full width at half maximum of the arterial input function curves (P = .14) or the SNR values (0.6) between the half-dose and full-dose groups.ConclusionsIn patients with acute stroke, combined low-dose contrast-enhanced MRA and dynamic susceptibility contrast perfusion at 3T is feasible and results in significant scan time and contrast dose reductions.

Background and purposeFurther improvement in acquisition speed is needed, if MR imaging is to compete with CT for evaluation of patients with acute ischemic stroke. The purpose of this study was to evaluate the feasibility of implementing an echo-planar fluid-attenuated inversion recovery (EPI-FLAIR) sequence into an acute MR stroke protocol with potential reduction in scan time and to compare the results with conventional FLAIR images.Materials and methodsFifty-two patients (28 men and 24 women; age range, 32-96 years) with acute ischemic stroke were prospectively evaluated with an acute stroke MR protocol, which included both conventional FLAIR and EPI-FLAIR imaging with integration of parallel acquisition. The image acquisition time was 52 seconds for EPI-FLAIR and 3 minutes for conventional FLAIR. FLAIR and EPI-FLAIR studies were assessed by 2 observers independently for image quality and conspicuity of hyperintensity in correlation with DWI and were rated as concordant or discordant. Coregistered FLAIR and EPI-FLAIR images were evaluated for signal intensity ratio of the DWI-positive lesion to contralateral normal white matter.ResultsAn estimated 96% of all FLAIR and EPI-FLAIR studies were rated of diagnostic image quality by both observers, with interobserver agreements of κ = 0.82 and κ = 0.63 for FLAIR and EPI-FLAIR, respectively. In 36 (95%) of 38 patients with acute infarction, FLAIR and EPI-FLAIR were rated concordant regarding DWI lesion. The mean ± standard deviation of the signal intensity ratio values on EPI-FLAIR and FLAIR for DWI-positive lesions were 1.28 ± 0.16 and 1.25 ± 0.17, respectively (P = .47), and demonstrated significant correlation (r = 0.899, z value = 8.677, P < .0001).ConclusionsIn patients with acute stroke, EPI-FLAIR is feasible with comparable qualitative and quantitative results to conventional FLAIR and results in reduced acquisition time.

Pediatric soft tissue sarcomas account for approximately 10% of all pediatric malignancies. Malignant ectomesenchymoma is rare biphasic sarcomas consisting of both mesenchymal and neuroectodermal elements. Approximately 64 cases have been reported in the literature and are believed to arise from pluripotent embryologic migratory neural crest cells. We report a 4-year-old boy who initially presented with a pelvic mass and inguinal lymphadenopathy at 6 months of age. Inguinal lymph node biopsy revealed a distinct biphasic tumor with microscopic and immunophenotypic characteristics diagnostic for both alveolar rhabdomyosarcoma and poorly differentiated neuroblastoma. The patient received national protocol chemotherapy against rhabdomyosarcoma with good response and presented with a cerebellar mass 21 months later. The metastatic tumor revealed sheets of primitive tumor cells and diagnostic areas of rhabdomyosarcoma and neuroblastoma were identified only by immunohistochemistry. Cytogenetic analysis of metastatic tumor demonstrated complex karyotype with multiple chromosomal deletions and duplications. The patient received national protocol chemotherapy against neuroblastoma and adjuvant radiotherapy after surgical resection of the cerebellar tumor with good response. He is currently off from any treatment for 18 months with no evidence of tumor recurrence or metastasis.

To investigate a high spatial resolution peripheral contrast-enhanced MR angiography (CE-MRA) protocol, applying a dedicated multi-channel array coil and accelerated parallel acquisition at 3.0T in evaluation of patients with peripheral vascular disease. Twenty patients with peripheral vascular disease underwent multi-station high spatial resolution peripheral CE-MRA at 3T. The image quality, presence of venous contamination, image noise, and artifact were evaluated by 2 radiologists independently. Assessment of arterial disease for 540 arterial segments was performed, and findings were correlated with conventional catheter angiography in 10 patients. All studies were yielded high diagnostic image quality. Venous contamination and artifact were minimal and never interfered with diagnosis. Sixty seven arterial segments with significant stenoses (>0%) were detected by observers with excellent interobserver agreement (kappa = 0.82; 95% CI: 0.76, 0.88). There was a significant correlation between CE-MRA and conventional angiography (Rs = 0.91 and 0.94 for reader 1 and 2, respectively) for the assessment of the degree of stenosis. Higher available SNR at 3T in combination with multi-coil technology and accelerated parallel acquisition, result in acquisition of nearly isotropic submillimeter 3D voxels throughout the entire peripheral arterial tree with diagnostic image quality and favorable comparative analysis with catheter angiography. [ABSTRACT FROM AUTHOR]

The quality of magnetic resonance (MR) angiography could be substantially improved over the past several years based on the introduction and application of parallel imaging, new sequence techniques, such as, e.g., centric k-space trajectories, dedicated contrast agents, and clinical high-field scanners. All of these techniques have played an important role to improve image resolution or decrease acquisition time for the dedicated examination of a single vascular territory. However, whole-body MR angiography may be the application with the potential to profit most from these technical advances. The present review article describes the technical innovations with a focus on parallel imaging at high field strength and the impact on whole-body MR angiography. The clinical value of advanced whole-body MR angiography techniques is illustrated by characteristic cases. [ABSTRACT FROM AUTHOR]

Background: Poor venous outflow (VO) profiles are associated with unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO), despite achieving successful reperfusion. The objective of this study is to assess the association between mortality and prolonged venous transit (PVT), a novel visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps., Methods: We performed a retrospective analysis of prospectively collected data from consecutive adult patients with AIS-LVO with successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b/2c/3). PVT+ was defined as Tmax ≥10 s timing on CTP Tmax maps in at least one of the following: superior sagittal sinus (proximal venous drainage) and/or torcula (deep venous drainage). PVT- was defined as lacking this in both regions. The primary outcome was mortality at 90 days. In a 1:1 propensity score-matched cohort, regressions were performed to determine the effect of PVT on 90-day mortality., Results: In 127 patients of median (IQR) age 71 (64-81) years, mortality occurred in a significantly greater proportion of PVT+ patients than PVT- patients (32.5% vs 12.6%, P=0.01). This significant difference persisted after matching (P=0.03). PVT+ was associated with a significantly increased likelihood of 90-day mortality (OR 1.22 (95% CI 1.02 to 1.46), P=0.03) in the matched cohort., Conclusions: PVT+ was significantly associated with 90-day mortality despite successful reperfusion therapy in patients with AIS-LVO. PVT is a simple VO profile marker with potential as an adjunctive metric during acute evaluation of AIS-LVO patients. Future studies will expand our understanding of using PVT in the evaluation of patients with AIS-LVO., Competing Interests: Competing interests: VSY, JJH and GWA are consultants for iSchemaView (Menlo Park, California, USA) not related to the submitted work., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

The cerebral blood volume index (CBV index) is a perfusion-based marker of collateral status. Several real-world data analyses from observational stroke cohorts have established relationships between this parameter and a range of favorable and unfavorable stroke outcomes. In this review, an overview is provided of the CBV index, within the context of thrombectomy-treated large vessel and medium vessel occlusion ischemic strokes. The current literature is summarized describing the CBV index and its association with a variety of efficacy, safety, and clinical outcome measures during the thrombectomy course and post-treatment recovery in both large vessel occlusion and medium vessel occlusion strokes. The range of CBV index value thresholds that have been identified and are able to differentiate between favorable and unfavorable outcomes across different clinical scenarios are summarized. This review underscores the need for additional analyses to further explore the CBV index in other clinical outcome contexts and for future prospective studies to validate the CBV index in thrombectomy-treated large vessel and medium vessel occlusion strokes, especially with increasing use of thrombectomy for treating medium vessel occlusions., Competing Interests: Competing interests: VY, GWA, and JJH are consultants for iSchemaView (Menlo Park, California, USA)., (© Author(s) (or their employer(s)) 2025. No commercial re-use. See rights and permissions. Published by BMJ Group.)

Background: Pretreatment CT perfusion (CTP) marker relative cerebral blood volume (rCBV) < 42% lesion volume has recently shown to predict poor collateral status and poor 90-day functional outcome. However, there is a paucity of studies assessing its association with hemorrhagic transformation (HT). Here, we aim to assess the relationship between rCBV < 42% lesion volume with HT., Methods: In this retrospective study, we included patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO) of anterior circulation who had successful recanalization from two comprehensive stroke centers between 9/1/2017 and 10/01/2023. Successful recanalization was defined as modified treatment in cerebral infarction (mTICI) 2b or greater. Logistic regression analysis and ROC analysis were used to assess the relationship between rCBV <42% and HT., Results: In total, 150 patients (median age: 69 years, 58.7% female) met our inclusion criteria. On multivariable logistic regression analysis, taking into account age, sex, hypertension, hyperlipidemia, diabetes, prior stroke or transient ischemic attack, admission National Institute of Health stroke scale (NIHSS), Alberta Stroke Program Early CT Score (ASPECTS), and intravenous thrombolysis, rCBV <34% (aOR:1.01, P  < .05), rCBV <38% (aOR:1.01, P  < .05) and rCBV <42% (aOR:1.01, P  < .05) lesion volumes were independently associated with HT. On ROC analysis rCBV < 42% (AUC = 0.61, P  < .05) performed slightly better than rCBV < 38% (AUC = 0.59, P  < .05) and rCBV < 34% (AUC = 0.59, P  < .05) in predicting HT., Conclusion: The rCBV <42% lesion volume is independently associated with HT in AIS-LVO patients who underwent successful recanalization., Competing Interests: Declaration of conflicting interestsDrs. Dhairya Lakhani, Greg Albers, Jeremy Heit, and Vivek Yedavalli are consultants for Rapid (iSchemaView, Menlo Park, CA).

Background and Purpose: Prolonged length of stay (LOS) following a stroke is associated with unfavorable clinical outcomes. Factors predicting LOS in medium vessel occlusion (MeVO), impacting up to 40% of acute ischemic stroke (AIS) cases, remain underexplored. This study aims to investigate the predictors of LOS in AIS-MeVO., Methods: We conducted a retrospective analysis of prospectively maintained stroke databases, comprising AIS cases with MeVO in the anterior circulation, assessed by adequate CT perfusion (CTP). Baseline and clinical data were obtained from electronic health records. Alberta Stroke Program Early CT Scores (ASPECTS) were calculated from non-contrast head CT. The perfusion mismatch volume (time to maximum > 6 s minus relative cerebral blood flow <30%) volume was reported from CTP. Multiple regression was employed to examine the relationship between baseline parameters and hospital LOS., Results: A total of 133 patients (median age 71 [interquartile range 63-80] years, 59.4% females) were included in the study cohort. The perfusion mismatch volume significantly positively correlated with LOS (r = 0.264, p = 0.004). After adjusting for age, sex, hypertension, diabetes, prior stroke or transient ischemic attack, admission NIHSS, ASPECTS, Tan score, intravenous thrombolysis, mechanical thrombectomy (MT), and hemorrhagic transformation, a larger mismatch volume remained independently associated with longer hospital stays (β = 0.209, 95% confidence interval [CI] 0.006-0.412, p = 0.045). Additional significant determinants of longer hospital stay included admission NIHSS (β = 0.250, 95% CI: 0.060-0.440, p = 0.010) and MT (β = 0.208, 95% CI: 0.006-0.410, p = 0.044). Among patients who underwent MT (n = 83), multiple regression analysis incorporating both perfusion mismatch volume and admission NIHSS revealed that perfusion mismatch volume remained independently associated with LOS (β = 0.248, 95% CI: 0.019-0.471, p = 0.033), while admission NIHSS did not retain significance (β = 0.208, 95% CI: 0.019-0.433, p = 0.071)., Conclusions: In our cohort of AIS patients with MeVO in the anterior circulation, and particularly in those who underwent MT, the perfusion mismatch volume serves as an independent predictor of LOS. These findings offer critical valuable insights in clinical assessments and decision-making protocols of MT in AIS-MeVO., (© 2025 American Society of Neuroimaging.)

Background and Purpose: Prolonged venous transit (PVT), derived from computed tomography perfusion (CTP) time-to-maximum (T max ) maps, reflects compromised venous outflow (VO) in acute ischemic stroke due to large vessel occlusion (AIS-LVO). Poor VO is associated with worse clinical outcomes, but pre-treatment markers predictive of PVT are not well described., Methods: We conducted a retrospective analysis of 189 patients with anterior circulation AIS-LVO who underwent baseline CT evaluation, including non-contrast CT, CT angiography, and CTP. PVT was assessed on T max maps; PVT+ was defined as T max  ≥ 10 s within the posterior superior sagittal sinus or torcula. Baseline clinical data were collected. Multivariable logistic regression identified independent associations between pre-treatment markers and PVT., Results: PVT+ was identified in 65 patients (34%). In multivariable analysis, higher admission National Institutes of Health Stroke Scale (NIHSS) scores (adjusted odds ratio [aOR], 1.05 per point; 95% confidence interval [CI], 1.01-1.11; P  =  0.028) and male sex (aOR, 1.98; 95% CI, 1.03-3.89; P  =  0.043) were independently associated with PVT+., Conclusions: Higher admission NIHSS scores and male sex are independently associated with PVT in anterior circulation AIS-LVO, suggesting that readily available clinical markers may help identify patients with poor VO profiles., (© 2025 American Society of Neuroimaging.)