Infectious Diseases of the Brain and Spine: Parasitic and Other Atypical Transmissible Diseases.

Atypical infections of the brain and spine caused by parasites occur in immunocompetent and immunosuppressed hosts, related to exposure and more prevalently in endemic regions. In the United States, the most common parasitic infections that lead to central nervous system manifestations include cysticercosis, echinococcosis, and toxoplasmosis, with toxoplasmosis being the most common opportunistic infection affecting patients with advanced HIV/AIDS. Another rare but devastating transmittable disease is prion disease, which causes rapidly progressive spongiform encephalopathies. Familiarity and understanding of various infectious agents are a crucial aspect of diagnostic neuroradiology, and recognition of unique features can aid timely diagnosis and treatment.

Infectious Diseases of the Brain and Spine: Fungal Diseases.

Advances in treatments of autoimmune diseases, acquired immunodeficiency syndrome, organ transplantation, and the use of long-term devices have increased the rates of atypical infections due to prolonged immune suppression. There is a significant overlap in imaging findings of various fungal infections affecting the central nervous system (CNS), often mimicking those seen in neoplastic and noninfectious inflammatory conditions. Nonetheless, there are imaging characteristics that can aid in distinguishing certain atypical infections. Hence, familiarity with a wide range of infectious agents is an important part of diagnostic neuroradiology. In this article, an in-depth review of fungal diseases of the CNS is provided.

Brain AVM compactness score in children with hereditary hemorrhagic telangiectasia.

OBJECTIVE: The brain arteriovenous malformation (BAVM) nidus compactness score (CS), determined on angiography, predicts BAVM recurrence after surgical resection among children with sporadic BAVMs. We measured the angiographic CS for BAVMs among children with hereditary hemorrhagic telangiectasia (HHT) to determine CS characteristics in this population. METHODS: A pediatric interventional neuroradiologist reviewed angiograms to determine the CS of BAVMs in children with HHT recruited to the BVMC. CS is based on overall nidus and perinidal anomalous vessel compactness. CS categories included 1 = diffuse nidus, 2 = intermediate nidus, and 3 = compact nidus. RESULTS: Forty-eight of 78 children (61.5%) with HHT and brain vascular malformations had a conventional angiogram; 47 (97.9%) angiograms were available. Fifty-four BAVMs were identified in 40 of these 47 children (85.1%). Of 54 BAVMs in children with HHT, CS was 1 in 7 (13%), 2 in 29 (53.7%), and 3 in 18 BAVMs (33.3%) compared with CS of 1 in six (26.1%), 2 in 15 (65.2%), and 3 in 2 BAVMs (8.7%) among 23 previously reported children with sporadic BAVMs, p = 0.045 (Fisher's exact). Seven children with HHT had intracranial hemorrhage: 4 had CS = 3, 1 had CS = 2, and 2 had CS = 1. CONCLUSIONS: A range of CSs exists across HHT BAVMs, suggesting it may be an angiographic measure of interest for future studies of BAVM recurrence and hemorrhage risk. Children with HHT may have more compact niduses compared to children with sporadic BAVMs. Additional research should determine whether CS affects hemorrhage risk or post-surgical recurrence risk in HHT-associated BAVMs, which could be used to direct BAVM treatment.

Velocity-Selective Arterial Spin Labeling Perfusion in Monitoring High Grade Gliomas Following Therapy: Clinical Feasibility at 1.5T and Comparison with Dynamic Susceptibility Contrast Perfusion.

MR perfusion imaging is important in the clinical evaluation of primary brain tumors, particularly in differentiating between true progression and treatment-induced change. The utility of velocity-selective ASL (VSASL) compared to the more commonly utilized DSC perfusion technique was assessed in routine clinical surveillance MR exams of 28 patients with high-grade gliomas at 1.5T. Using RANO criteria, patients were assigned to two groups, one with detectable residual/recurrent tumor ("RT", n = 9), and the other with no detectable residual/recurrent tumor ("NRT", n = 19). An ROI was drawn to encompass the largest dimension of the lesion with measures normalized against normal gray matter to yield rCBF and tSNR from VSASL, as well as rCBF and leakage-corrected relative CBV (lc-rCBV) from DSC. VSASL (rCBF and tSNR) and DSC (rCBF and lc-rCBV) metrics were significantly higher in the RT group than the NRT group allowing adequate discrimination (p < 0.05, Mann-Whitney test). Lin's concordance analyses showed moderate to excellent concordance between the two methods, with a stronger, moderate correlation between VSASL rCBF and DSC lc-rCBV (r = 0.57, p = 0.002; Pearson's correlation). These results suggest that VSASL is clinically feasible at 1.5T and has the potential to offer a noninvasive alternative to DSC perfusion in monitoring high-grade gliomas following therapy.

Downfield Proton MRSI at 3 Tesla: A Pilot Study in Human Brain Tumors.

PURPOSE: To investigate the use of 3D downfield proton magnetic resonance spectroscopic imaging (DF-MRSI) for evaluation of tumor recurrence in patients with glioblastoma (GBM). METHODS: Seven patients (4F, age range 44-65 and mean ± standard deviation 59.3 ± 7.5 years) with previously treated GBM were scanned using a recently developed 3D DF-MRSI sequence at 3T. Short TE 3D DF-MRSI and water reference 3D-MRSI scans were collected with a nominal spatial resolution of 0.7 cm3. DF volume data in eight slices covered 12 cm of brain in the cranio-caudal axis. Data were analyzed using the 'LCModel' program and a basis set containing nine peaks ranging in frequency between 6.83 to 8.49 ppm. The DF8.18 (assigned to amides) and DF7.90 peaks were selected for the creation of metabolic images and statistical analysis. Longitudinal MR images and clinical history were used to classify brain lesions as either recurrent tumor or treatment effect, which may include necrosis. DF-MRSI data were compared between lesion groups (recurrent tumor, treatment effect) and normal-appearing brain. RESULTS: Of the seven brain tumor patients, two were classified as having recurrent tumor and the rest were classified as treatment effect. Amide metabolite levels from recurrent tumor regions were significantly (p < 0.05) higher compared to both normal-appearing brain and treatment effect regions. Amide levels in lesion voxels classified as treatment effect were significantly lower than normal brain. CONCLUSIONS: 3D DF-MRSI in human brain tumors at 3T is feasible and was well tolerated by all patients enrolled in this preliminary study. Amide levels measured by 3D DF-MRSI were significantly different between treatment effect and tumor regrowth.

Risk factors and clinical features associated with basal ganglia manganese deposition in patients with hereditary hemorrhagic telangiectasia.

BACKGROUND: T1-hyperintensity of the basal ganglia (BG) due to manganese deposition is a known radiologic finding in patients with hereditary hemorrhagic telangiectasia (HHT), but risk factors and associated clinical manifestations are unclear. This study conducted a quantitative analysis of the association of T1-hyperintensity in HHT patients with specific risk factors, signs, and symptoms. METHODS: Patients seen at our center between 2005 and 2020 with a definitive diagnosis of HHT who had an available non-contrast T1-weighted brain MRI were included. Hyperintensity was evaluated using oval regions of interest measurements. The BG: thalamus intensity ratio was used to quantitatively evaluate T1-hyperintensity. Patient laboratory values and clinical findings were collected from electronic medical records. Hyperintensity was analyzed for its association with laboratory values, and clinical findings. Variables were analyzed through regression analysis. RESULTS: A total of 239 patients were included in this study. On 1.5 T scanners, values that were significant on multivariable regression analysis were age (p < .001), hepatic AVMs (p < .001), iron deficiency anemia (p = .0021), and cirrhosis (p = .016). On 3 T scanners, values that were significant on multivariable analysis were hepatic AVMs (p = .0024) and cirrhosis (p = .0056). On 3 T scanners, hyperintensity was significantly associated with tremor (OR = 1.17, p = .033), restless leg syndrome (OR = 1.22, p = .0086), and memory problems (OR = 1.17, p = .046). CONCLUSIONS: BG hyperintensity due to manganese deposition is significantly associated with hepatic risk factors on 1.5 T and 3 T scanners and iron deficiency anemia on 1.5 T scanners. On 3 T scanners, T1-hyperintensity is associated with neuropsychiatric signs and symptoms, such as tremor, restless leg syndrome, and memory problems.

Deep-learning-enabled brain hemodynamic mapping using resting-state fMRI.

Cerebrovascular disease is a leading cause of death globally. Prevention and early intervention are known to be the most effective forms of its management. Non-invasive imaging methods hold great promises for early stratification, but at present lack the sensitivity for personalized prognosis. Resting-state functional magnetic resonance imaging (rs-fMRI), a powerful tool previously used for mapping neural activity, is available in most hospitals. Here we show that rs-fMRI can be used to map cerebral hemodynamic function and delineate impairment. By exploiting time variations in breathing pattern during rs-fMRI, deep learning enables reproducible mapping of cerebrovascular reactivity (CVR) and bolus arrival time (BAT) of the human brain using resting-state CO2 fluctuations as a natural "contrast media". The deep-learning network is trained with CVR and BAT maps obtained with a reference method of CO2-inhalation MRI, which includes data from young and older healthy subjects and patients with Moyamoya disease and brain tumors. We demonstrate the performance of deep-learning cerebrovascular mapping in the detection of vascular abnormalities, evaluation of revascularization effects, and vascular alterations in normal aging. In addition, cerebrovascular maps obtained with the proposed method exhibit excellent reproducibility in both healthy volunteers and stroke patients. Deep-learning resting-state vascular imaging has the potential to become a useful tool in clinical cerebrovascular imaging.

Silent cerebral infarction during immune TTP remission: prevalence, predictors, and impact on cognition.

Immune thrombotic thrombocytopenic purpura (iTTP) survivors have increased risk of cardiovascular disease, including strokes, and report persistent cognitive difficulties during remission. We conducted this prospective study involving iTTP survivors during clinical remission to determine the prevalence of silent cerebral infarction (SCI), defined as magnetic resonance imaging (MRI) evidence of brain infarction without corresponding overt neurodeficits. We also tested the hypothesis that SCI is associated with cognitive impairment, assessed using the National Institutes of Health ToolBox Cognition Battery. For cognitive assessments, we used fully corrected T scores adjusted for age, sex, race, and education. Based on the diagnostic and statistical manual 5 criteria, we defined mild and major cognitive impairment as T scores with a 1 or 2 standard deviation (SD) and >2 SD below the mean on at least 1 test, respectively. Forty-two patients were enrolled, with 36 completing MRIs. SCI was present in 50% of the patients (18), of which 8 (44.4%) had prior overt stroke including during acute iTTP. Patients with SCI had higher rates of cognitive impairment (66.7% vs 27.7%; P = .026), including major cognitive impairment (50% vs 5.6%; P = .010). In separate logistic regression models, SCI was associated with any (mild or major) cognitive impairment (odds ratio [OR] 10.5 [95% confidence interval (95% CI), 1.45-76.63]; P = .020) and major cognitive impairment (OR 7.98 [95% CI, 1.11-57.27]; P = .039) after adjusting for history of stroke and Beck depression inventory scores. MRI evidence of brain infarction is common in iTTP survivors; the strong association of SCI with impaired cognition suggests that these silent infarcts are neither silent nor innocuous.

Test-retest reliability of 3D velocity-selective arterial spin labeling for detecting normal variations of cerebral blood flow.

Velocity-selective inversion (VSI) based velocity-selective arterial spin labeling (VSASL) has been developed to measure cerebral blood flow (CBF) with low susceptibility to the prolonged arterial transit time and high sensitivity to brain perfusion signal. The purpose of this magnetic resonance imaging study is to evaluate the test-retest reliability of a VSI-prepared 3D VSASL protocol with whole-brain coverage to detect baseline CBF variations among cognitively normal participants in different brain regions. Coefficients of variation (CoV) of both absolute and relative CBF across scans or sessions, subjects, and gray matter regions were calculated, and corresponding intraclass correlation coefficients (ICC) were computed. The higher between-subject CoV of absolute CBF (13.4 ± 2.0%) over within-subject CoV (within-session: 3.8 ± 1.1%; between-session: 4.9 ± 0.9%) yielded moderate to excellent ICC (within-session: 0.88±0.08; between-session: 0.77±0.14) to detect normal variations of individual CBF. The higher between-region CoV of relative CBF (11.4 ± 3.0%) over within-region CoV (within-session: 2.3 ± 0.9%; between-session: 3.3 ± 1.0%) yielded excellent ICC (within-session: 0.92±0.06; between-session: 0.85±0.12) to detect normal variations of regional CBF. Age, blood pressure, end-tidal CO2, and hematocrit partially explained the variability of CBF across subjects. Together these results show excellent test-retest reliability of VSASL to detect both between-subject and between-region variations supporting its clinical utility.

Cannabidiol Treatment for Neurological, Cognitive, and Psychiatric Symptoms in Sturge-Weber Syndrome.

BACKGROUND: A prior drug trial of cannabidiol for treatment-resistant epilepsy in patients with Sturge-Weber syndrome (SWS), a rare neurovascular condition, implicated improvements in neurological, quality of life (QOL), neuropsychologic, psychiatric, and motor outcomes. METHODS: Ten subjects with SWS brain involvement, controlled seizures, and cognitive impairments received study drug in this Johns Hopkins institutional review board-approved, open-label, prospective drug trial. Oral cannabidiol was taken for six months (dose ranged from 5 to 20 mg/kg/day). SWS neuroscore, port-wine birthmark score, QOL, and adverse events were recorded every four to 12 weeks. Neuropsychologic, psychiatric, and motor assessments were administered at baseline and six months' follow-up. Most evaluations were conducted virtually due to the coronavirus disease 2019 pandemic. RESULTS: Cannabidiol was generally well tolerated. Six subjects reported mild to moderate side effects related to study drug and continued on drug; one subject withdrew early due to moderate side effects. No seizures were reported. Significant improvements in SWS neuroscore, patient-reported QOL, anxiety and emotional regulation, and report of bimanual ability use were noted. Migraine QOL scores were high at baseline in these subjects, and remained high. Neuropsychologic and other QOL and motor outcomes remained stable, with some within-subject improvements noted. CONCLUSIONS: Further studies are needed to determine whether Epidiolex can improve quality of life and be beneficial for neurological, anxiety, and motor impairments in SWS independent of seizure control. Large multicentered studies are needed to extend these preliminary findings.

Study protocol: retrospectively mining multisite clinical data to presymptomatically predict seizure onset for individual patients with Sturge-Weber.

INTRODUCTION: Secondary analysis of hospital-hosted clinical data can save time and cost compared with prospective clinical trials for neuroimaging biomarker development. We present such a study for Sturge-Weber syndrome (SWS), a rare neurovascular disorder that affects 1 in 20 000-50 000 newborns. Children with SWS are at risk for developing neurocognitive deficit by school age. A critical period for early intervention is before 2 years of age, but early diagnostic and prognostic biomarkers are lacking. We aim to retrospectively mine clinical data for SWS at two national centres to develop presymptomatic biomarkers. METHODS AND ANALYSIS: We will retrospectively collect clinical, MRI and neurocognitive outcome data for patients with SWS who underwent brain MRI before 2 years of age at two national SWS care centres. Expert review of clinical records and MRI quality control will be used to refine the cohort. The merged multisite data will be used to develop algorithms for abnormality detection, lesion-symptom mapping to identify neural substrate and machine learning to predict individual outcomes (presence or absence of seizures) by 2 years of age. Presymptomatic treatment in 0-2 years and before seizure onset may delay or prevent the onset of seizures by 2 years of age, and thereby improve neurocognitive outcomes. The proposed work, if successful, will be one of the largest and most comprehensive multisite databases for the presymptomatic phase of this rare disease. ETHICS AND DISSEMINATION: This study involves human participants and was approved by Boston Children's Hospital Institutional Review Board: IRB-P00014482 and IRB-P00025916 Johns Hopkins School of Medicine Institutional Review Board: NA_00043846. Participants gave informed consent to participate in the study before taking part. The Institutional Review Boards at Kennedy Krieger Institute and Boston Children's Hospital approval have been obtained at each site to retrospectively study this data. Results will be disseminated by presentations, publication and sharing of algorithms generated.

Perfusion measurement in brain gliomas using velocity-selective arterial spin labeling: comparison with pseudo-continuous arterial spin labeling and dynamic susceptibility contrast MRI.

OBJECTIVES: To evaluate the performance of velocity-selective (VS) ASL among patients with untreated gliomas by comparing with both pseudo-continuous (PC) ASL and dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI). METHODS: Forty-four consecutive patients with newly diagnosed glioma who underwent preoperative perfusion MRI including VSASL, PCASL, and DSC-PWI between 2017 and 2019 were retrospectively evaluated. Visual inspection was performed to evaluate the tumor signal intensity relative to gray matter based on 1-5 score criteria and weighted kappa was used to evaluate the pair-wise concordance between VSASL or PCASL and DSC-PWI. The relative tumor blood flow (rTBF) was measured from sampling intra-tumoral areas of hot-spot on the blood flow map and normalized against the contralateral normal gray matter blood flow. Linear regression and Bland-Altman analyses were performed to evaluate the correlation and agreement of rTBF measurements between ASL methods and DSC-PWI. The ROC analysis was constructed to determine the diagnostic performance of three perfusion methods for grading gliomas. RESULTS: TBF maps derived from VSASL were more comparable with DSC-PWI than PCASL on visual inspection (weighted kappa of 0.90 vs 0.68). In quantitative analysis, VSASL-rTBF yielded higher correlation with the values from DSC-PWI than PCASL-rTBF (R2 = 80% vs 47%, p < 0.001 for both). Both ASL and DSC-derived rTBF showed good distinction between low-grade and high-grade gliomas (p < 0.001). Compared to PCASL, VSASL yielded superior diagnostic sensitivity, specificity, and accuracy in glioma grading. CONCLUSIONS: VSASL showed great promise for accurate quantification of TBF and could potentially improve the diagnostic performance of ASL in preoperative grading of gliomas. KEY POINTS: • VSASL demonstrated a greater agreement with DSC-PWI than with PCASL on visual inspection and perfusion quantification. • VSASL showed a higher diagnostic sensitivity, negative predictive value, and accuracy than PCASL for glioma grading. • With the advantages of insensitivity to transit delay and no need of prescribing a labeling plane, VSASL could potentially improve the diagnostic performance of ASL for a more accurate, noninvasive quantification of TBF in patients with glioma.

Quantitative EEG improves prediction of Sturge-Weber syndrome in infants with port-wine birthmark.

OBJECTIVE: Port-wine birthmark (PWB) is a common occurrence in the newborn, and general pediatricians, dermatologists, and ophthalmologists are often called on to make an assessment of risk for Sturge-Weber syndrome (SWS) due to workforce shortages in pediatric neurologists and MRI's low sensitivity for SWS brain involvement in infants. We therefore aimed to develop a quantitative EEG (qEEG) approach to safely screen young infants with PWB for SWS risk and optimal timing of diagnostic MRI. METHODS: Forty-eight infants (prior to first birthday) underwent EEG recording. Signal processing methods compared voltage between left and right sides using a previously defined pipeline and diagnostic threshold. In this test sample, we compared sensitivity/specificity of the qEEG metric against MRI performed after the first birthday. We also used likelihood ratio testing to determine whether qEEG adds incremental information beyond topographical extent of PWB, another risk marker of brain involvement. RESULTS: qEEG helped predict SWS risk in the first year of life (p = 0.031), with a sensitivity of 50% and a specificity of 81%. It added about 40% incremental information beyond PWB extent alone (p = 0.042). CONCLUSION: qEEG adds information to risk prediction in infants with facial PWB. SIGNIFICANCE: qEEG can be used to help determine whether to obtain an MRI in the first year of life. The data collected can assist in developing a predictive model risk calculator that incorporates both PWB extent and qEEG results, which can be validated and then employed in the community.

Safety and diagnostic efficacy of gadoteridol for magnetic resonance imaging of the brain and spine in children 2 years of age and younger.

BACKGROUND: Neonates and young children require efficacious magnetic resonance imaging (MRI) examinations but are potentially more susceptible to the short- and long-term adverse effects of gadolinium-based contrast agents due to the immaturity of their body functions. OBJECTIVE: To evaluate the acute safety and diagnostic efficacy of gadoteridol (ProHance) for contrast-enhanced MRI of the central nervous system (CNS) in children ≤2 years of age. MATERIALS AND METHODS: One hundred twenty-five children ≤2 years old (including 57 children <6 months old) who underwent contrast-enhanced MRI of the CNS with gadoteridol at 0.1 mmol/kg body weight were retrospectively enrolled at five imaging centers. Safety data were assessed for acute/subacute adverse events in the 48 h following gadoteridol administration and, when available, vital signs, electrocardiogram (ECG) and clinical laboratory values obtained from blood samples taken from 48 h before until 48 h following the MRI exam. The efficacy of gadoteridol-enhanced MRI compared to unenhanced MRI for disease diagnosis was evaluated prospectively by three blinded, unaffiliated readers. RESULTS: Thirteen changes of laboratory values (11 mild, 1 moderate, 1 unspecified) were reported as adverse events in 7 (5.6%) patients. A relationship to gadoteridol was deemed possible though doubtful for two of these adverse events in two patients (1.6%). There were no clinical adverse events, no serious adverse events and no clinically meaningful changes in vital signs or ECG recordings. Accurate differentiation of tumor from non-neoplastic disease, and exact matching of specific MRI-determined diagnoses with on-site final diagnoses, was achieved in significantly more patients by each reader following the evaluation of combined pre- and post-contrast images compared to pre-contrast images alone (84.6-88.0% vs. 70.9-76.9%; P≤0.006 and 67.5-79.5% vs. 47.0-66.7%; P≤0.011, respectively). CONCLUSION: Gadoteridol at 0.1 mmol/kg body weight is safe, well tolerated and effective for contrast-enhanced MRI of the CNS in children ≤2 years of age.

Dose-Lowering in Contrast-Enhanced MRI of the Central Nervous System: A Retrospective, Parallel-Group Comparison Using Gadobenate Dimeglumine.

BACKGROUND: Concerns over gadolinium (Gd) retention encourage the use of lower Gd doses. However, lower Gd doses may compromise imaging performance. Higher relaxivity gadobenate may be suited to reduced dose protocols. PURPOSE: To compare 0.05 mmol/kg and 0.1 mmol/kg gadobenate in patients undergoing enhanced MRI of the central nervous system (CNS). STUDY TYPE: Retrospective, multicenter. POPULATION: Three hundred and fifty-two patients receiving 0.05 (n = 181) or 0.1 (n = 171) mmol/kg gadobenate. FIELD STRENGTH/SEQUENCES: 1.5 T and 3.0 T/precontrast and postcontrast T1-weighted spin echo/fast spin echo (SE/FSE) and/or gradient echo/fast field echo (GRE/FFE); precontrast T2-weighted FSE and T2-FLAIR. ASSESSMENT: Images of patients with extra-axial lesions at 1.5 T or any CNS lesion at 3.0 T were reviewed by three blinded, independent neuroradiologists for qualitative (lesion border delineation, internal morphology visualization, contrast enhancement; scores from 1 = poor to 4 = excellent) and quantitative (lesion-to-brain ratio [LBR], contrast-to-noise ratio [CNR]; SI measurements at regions-of-interest on lesion and normal parenchyma) enhancement measures. Noninferiority of 0.05 mmol/kg gadobenate was determined for each qualitative endpoint if the lower limit of the 95% confidence interval (CI) for the difference in precontrast + postcontrast means was above a noninferiority margin of -0.4. STATISTICAL TESTS: Student's t-test for comparison of mean qualitative endpoint scores, Wilcoxon signed rank test for comparison of LBR and CNR values; Wilcoxon rank sum test for comparison of SI changes. Tests were significant for P < 0.05. RESULTS: The mean change from precontrast to precontrast + postcontrast was significant for all endpoints. Readers 1, 2, and 3 evaluated 304, 225, and 249 lesions for 0.05 mmol/kg gadobenate, and 382, 309, and 298 lesions for 0.1 mmol/kg gadobenate. The lower limit of the 95% CI was above -0.4 for all comparisons. Significantly, higher LBR and CNR was observed with the higher dose. DATA CONCLUSION: 0.05 mmol/kg gadobenate was noninferior to 0.1 mmol/kg gadobenate for lesion visualization. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.

Improved velocity-selective-inversion arterial spin labeling for cerebral blood flow mapping with 3D acquisition.

PURPOSE: To further optimize the velocity-selective arterial spin labeling (VSASL) sequence utilizing a Fourier-transform based velocity-selective inversion (FT-VSI) pulse train, and to evaluate its utility for 3D mapping of cerebral blood flow (CBF) with a gradient- and spin-echo (GRASE) readout. METHODS: First, numerical simulations and phantom experiments were done to test the susceptibility to eddy currents and B1 field inhomogeneities for FT-VSI pulse trains with block and composite refocusing pulses. Second, the choices of the post-labeling delay (PLD) for FT-VSI prepared 3D VSASL were evaluated for the sensitivity to perfusion signal. The study was conducted among a young-age and a middle-age group at 3T. Both signal-to-noise ratio (SNR) and CBF were quantitatively compared with pseudo-continuous ASL (PCASL). The optimized 3D VSI-ASL was also qualitatively compared with PCASL in a whole-brain coverage among two healthy volunteers and a brain tumor patient. RESULTS: The simulations and phantom test showed that composite refocusing pulses are more robust to both eddy-currents and B1 field inhomogeneities than block pulses. 3D VSASL images with FT-VSI preparation were acquired over a range of PLDs and PLD = 1.2 s was selected for its higher perfusion signal. FT-VSI labeling produced quantitative CBF maps with 27% higher SNR in gray matter compared to PCASL. 3D whole-brain CBF mapping using VSI-ASL were comparable to the corresponding PCASL results. CONCLUSION: FT-VSI with 3D-GRASE readout was successfully implemented and showed higher sensitivity to perfusion signal than PCASL for both young and middle-aged healthy volunteers.

Parental Leave Policy in Radiology Residency Programs: Current Status.

PURPOSE: To explore the current status and determine the uniformity of parental leave policies among US radiology residency programs. METHODS: An electronic survey was developed and sent to 222 radiology residency program directors (PDs) in June 2019 to assess their policies and attitudes toward parental leave. The survey was administered via the Internet Qualtrics Research Suite (Qualtrics, Provo, Utah) format with four reminders sent over the course of 2 months before closing the data collection. RESULTS: In all, 74 PDs responded to the survey. Of those, 88% claimed to have a maternal leave policy (88% explicitly written and 77% paid); 80% had a paternal leave policy (88% explicitly written and 75% paid). The average length of maternal and paternal leaves was 7.4 ± 3.9 and 3.7 ± 3.7 weeks, respectively. Parental leaves were allocated at least every other year in over 70% of programs. Approximately 60% of the PDs required residents to make up call rotations for parental leaves. About 92% of responsive programs adjusted angiography and fluoroscopy rotations for trainees throughout the pregnancy or according to the trainee's request. Policies did not generally address issues of breastfeeding and nontraditional parenthood. CONCLUSION: The proportion of radiology programs with explicit maternal leave policies remained constant compared with previous surveys during the last two decades. However, there was a dramatic rise in the adoption of paternal leave policies. Overall, there was a lack of national uniformity in radiology residency programs' policies concerning parental leave, leaving open the possibility of national guidance in addressing the issue.

Atypical Intracerebral Developmental Venous Anomalies in Sturge-Weber Syndrome: A Case Series and Review of Literature.

BACKGROUND: Intracranial vascular abnormalities in Sturge-Weber syndrome, including leptomeningeal angiomatosis, anomalous cortical venous structures, and transmedullary developmental venous anomalies, are well recognized. Prominent vascular flow voids on T2-weighted magnetic resonance imaging (MRI) are occasionally identified in patients with Sturge-Weber syndrome, raising concern of arteriovenous malformations, a congenital high-flow vascular malformation with a risk of bleeding. METHODS: We report four patients with prominent flow voids on conventional MRI that suggested high-flow lesions. RESULTS: Diagnostic evaluation was performed with cerebral angiography in one patient and with a combination of magnetic resonance angiography and magnetic resonance venography in three patients. In all four patients, the conventional MRI-identified lesions represented prominent developmental venous anomalies and not arteriovenous malformations. CONCLUSIONS: This series highlights that developmental venous anomalies may appear in individuals with Sturge-Weber syndrome as unusually large and seemingly high-flow lesions on MRI. Noninvasive imaging with magnetic resonance angiography and magnetic resonance venography can be used in the management of such patients for further characterization of these vascular structures.

Correction to: White matter changes in primary central nervous system lymphoma patients treated with high-dose methotrexate with or without rituximab.

The following discrepancies and errors were found in the original publication.

White matter changes in primary central nervous system lymphoma patients treated with high-dose methotrexate with or without rituximab.

PURPOSE: White matter changes (WMCs) can develop following systemic chemotherapy in patients with primary central nervous system lymphomas (PCNSLs), but the frequency and extent of these changes is not well characterized. This single center retrospective semi-quantitative study was performed to determine the rate, timing and grade of WMC on MRI in adult patients with newly-diagnosed radiotherapy-naïve PCNSL undergoing treatment with high-dose methotrexate (HD-MTX) with or without the addition of rituximab (-R). METHODS: Serial MRI scans of consecutive adult PCNSL patients treated with HD-MTX ± R were assessed for WMC comparing the pre-treatment to post-treatment scans utilizing a 0-to-8-point severity scoring system. RESULTS: Forty-seven PCNSL patients treated with either HD-MTX-R (n = 34; median age 66, 50% male) or HD-MTX (n = 13; median age 53, 54% male) were included in the analysis. WMC were detected in 62% (95% CI 46-76%) overall, in 68% of the HD-MTX-R, and in 46% of the HD-MTX group. Among patients with WMC (n = 29), WMC were first detected at an average of 2.8 months from beginning of therapy in the HD-MTX-R versus at 10.7 months in the HD-MTX group. Average WMC non-zero scores when first detected following the start of treatment were 2.5 (± 1.1) in HD-MTX-R and 1.5 (± 0.6) in HD-MTX. CONCLUSIONS: Development of WMC in PCNSL patients treated with MTX and MTX-R is common. WMC changes appear to be more frequent, occur earlier and are more extensive in patients treated with HD-MTX-R compared to HD-MTX. Prospective studies are required to determine whether WMC correlate with survival or neurocognitive outcomes.