Contralateral Hemispheric Cerebral Blood Flow Measured With Arterial Spin Labeling Can Predict Outcome in Acute Stroke.

Background and Purpose- Imaging is frequently used to select acute stroke patients for intra-arterial therapy. Quantitative cerebral blood flow can be measured noninvasively with arterial spin labeling magnetic resonance imaging. Cerebral blood flow levels in the contralateral (unaffected) hemisphere may affect capacity for collateral flow and patient outcome. The goal of this study was to determine whether higher contralateral cerebral blood flow (cCBF) in acute stroke identifies patients with better 90-day functional outcome. Methods- Patients were part of the prospective, multicenter iCAS study (Imaging Collaterals in Acute Stroke) between 2013 and 2017. Consecutive patients were enrolled after being diagnosed with anterior circulation acute ischemic stroke. Inclusion criteria were ischemic anterior circulation stroke, baseline National Institutes of Health Stroke Scale score ≥1, prestroke modified Rankin Scale score ≤2, onset-to-imaging time <24 hours, with imaging including diffusion-weighted imaging and arterial spin labeling. Patients were dichotomized into high and low cCBF groups based on median cCBF. Outcomes were assessed by day-1 and day-5 National Institutes of Health Stroke Scale; and day-30 and day-90 modified Rankin Scale. Multivariable logistic regression was used to test whether cCBF predicted good neurological outcome (modified Rankin Scale score, 0-2) at 90 days. Results- Seventy-seven patients (41 women) met the inclusion criteria with median (interquartile range) age of 66 (55-76) yrs, onset-to-imaging time of 4.8 (3.6-7.7) hours, and baseline National Institutes of Health Stroke Scale score of 13 (9-20). Median cCBF was 38.9 (31.2-44.5) mL per 100 g/min. Higher cCBF predicted good outcome at day 90 (odds ratio, 4.6 [95% CI, 1.4-14.7]; P=0.01), after controlling for baseline National Institutes of Health Stroke Scale, diffusion-weighted imaging lesion volume, and intra-arterial therapy. Conclusions- Higher quantitative cCBF at baseline is a significant predictor of good neurological outcome at day 90. cCBF levels may inform decisions regarding stroke triage, treatment of acute stroke, and general outcome prognosis. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02225730.

Preoperative relative cerebral blood volume analysis in gliomas predicts survival and mitigates risk of biopsy sampling error.

Appropriate management of adult gliomas requires an accurate histopathological diagnosis. However, the heterogeneity of gliomas can lead to misdiagnosis and undergrading, especially with biopsy. We evaluated the role of preoperative relative cerebral blood volume (rCBV) analysis in conjunction with histopathological analysis as a predictor of overall survival and risk of undergrading. We retrospectively identified 146 patients with newly diagnosed gliomas (WHO grade II-IV) that had undergone preoperative MRI with rCBV analysis. We compared overall survival by histopathologically determined WHO tumor grade and by rCBV using Kaplan-Meier survival curves and the Cox proportional hazards model. We also compared preoperative imaging findings and initial histopathological diagnosis in 13 patients who underwent biopsy followed by subsequent resection. Survival curves by WHO grade and rCBV tier similarly separated patients into low, intermediate, and high-risk groups with shorter survival corresponding to higher grade or rCBV tier. The hazard ratio for WHO grade III versus II was 3.91 (p = 0.018) and for grade IV versus II was 11.26 (p < 0.0001) and the hazard ratio for each increase in 1.0 rCBV units was 1.12 (p < 0.002). Additionally, 3 of 13 (23%) patients initially diagnosed by biopsy were upgraded on subsequent resection. Preoperative rCBV was elevated at least one standard deviation above the mean in the 3 upgraded patients, suggestive of undergrading, but not in the ten concordant diagnoses. In conclusion, rCBV can predict overall survival similarly to pathologically determined WHO grade in patients with gliomas. Discordant rCBV analysis and histopathology may help identify patients at higher risk for undergrading.

Fast whole-brain three-dimensional macromolecular proton fraction mapping in multiple sclerosis.

PURPOSE: To evaluate the clinical utility of fast whole-brain macromolecular proton fraction ( MPF macromolecular proton fraction ) mapping in multiple sclerosis ( MS multiple sclerosis ) and compare MPF macromolecular proton fraction with established quantitative magnetic resonance (MR) imaging measures of tissue damage including magnetization transfer ( MT magnetization transfer ) ratio and relaxation rate (R1). MATERIALS AND METHODS: In this institutional review board-approved and HIPAA-compliant study, 14 healthy control participants, 18 relapsing-remitting MS multiple sclerosis ( RRMS relaxing-remitting MS ) patients, and 12 secondary progressive MS multiple sclerosis ( SPMS secondary progressive MS ) patients provided written informed consent and underwent 3-T MR imaging. Three-dimensional MPF macromolecular proton fraction maps were reconstructed from MT magnetization transfer -weighted images and R1 maps by the single-point method. Mean MPF macromolecular proton fraction , R1, and MT magnetization transfer ratio in normal-appearing white matter ( WM white matter ), gray matter ( GM gray matter ), and lesions were compared between subject groups by using analysis of variance. Correlations (Pearson r) between imaging data and clinical scores (Expanded Disability Status Scale [EDSS] and MS multiple sclerosis Functional Composite [ MSFC MS functional composite ]) were compared by using Hotelling-Williams test. RESULTS: RRMS relaxing-remitting MS patients had lower WM white matter and GM gray matter MPF macromolecular proton fraction than controls, with percentage decreases of 6.5% (P < .005) and 5.4% (P < .05). MPF macromolecular proton fraction in SPMS secondary progressive MS was reduced relative to RRMS relaxing-remitting MS in WM white matter , GM gray matter , and lesions by 6.4% (P < .005), 13.4% (P < .005), and 11.7% (P < .05), respectively. EDSS Expanded Disability Status Scale and MSFC MS functional composite demonstrated strongest correlations with MPF macromolecular proton fraction in GM gray matter (r = -0.74 and 0.81; P < .001) followed by WM white matter (r = -0.57 and 0.72; P < .01) and lesions (r = -0.42 and 0.50; P < .05). R1 and MT magnetization transfer ratio in all tissues were significantly less correlated with clinical scores than GM gray matter MPF macromolecular proton fraction (P < .05). CONCLUSION: MPF macromolecular proton fraction mapping enables quantitative assessment of demyelination in normal-appearing brain tissues and shows primary clinical relevance of GM gray matter damage in MS multiple sclerosis . MPF macromolecular proton fraction outperforms MT magnetization transfer ratio and R1 in detection of MS multiple sclerosis -related tissue changes.

Down syndrome associated moyamoya may worsen epilepsy control and can benefit from surgical revascularization.

OBJECTIVES: To examine outcome of bilateral extracranial to intracranial (EC-IC) bypass surgeries for a Down syndrome patient with hard-to-treat epilepsy and moyamoya. MATERIALS AND METHODS: Superficial temporal arteries were anastamosed using an indirect bypass technique to middle cerebral arteries bilaterally to help limit perfusion deficits and seizure controls. RESULTS: Two superficial temporal to middle cerebral artery indirect bypass surgeries were performed within 3 months. Post-revascularization improvements included seizure control, gait, perfusion, wakefulness, language and quality of life. CONCLUSION: In patients with Down syndrome and moyamoya, improvements in seizure control and quality of life may occur with EC-IC bypass procedures.

An epidural blood patch causing acute neurologic dysfunction necessitating a decompressive laminectomy.

OBJECTIVES: One risk with placement of an epidural blood patch (EDBP) is spinal cord or nerve root compression resulting from the epidural blood volume injected, a complication necessitating immediate surgical decompression. We could not find a previous report of this in the literature. Here, we review and discuss one such case. CASE REPORT: A patient was treated with 2 EDBPs for a presumptive cerebrospinal fluid leak 3 weeks after an epidural steroid injection. The second EDBP was performed under direct fluoroscopic guidance, yet resulted in spinal cord compression with radiologic evidence of an epidural hematoma. The patient developed acute cauda equina syndrome and required an emergent decompressive laminectomy resulting in partial resolution of neurological symptoms. One year after the procedure, the patient has recovered most of her motor function but with some persistent numbness below the left knee and a left foot drop. CONCLUSIONS: A cauda equina syndrome from an epidural hematoma may occur as a rare complication of an EDBP, even with direct fluoroscopic guidance. Early diagnosis of symptoms and prompt surgical evacuation of an epidural hematoma is essential and may result in the resolution of symptoms. This complication remains a rare occurrence and should not deter the performance of an EDBP, when indicated.

Clinical manifestations and diagnostic imaging of brain tumors.

The clinical manifestations of intracranial tumors are usually referable to the anatomic area of the brain involved or adjacent structures. Some anatomic regions may allow a tumor to reach substantial size while remaining clinically silent. In contrast, small lesions in critical areas are more likely to present early. The initial diagnosis of intracranial tumors is most efficiently made by imaging. This article discusses the clinicoanatomic features and imaging characteristics of brain tumors, including the use of dynamic susceptibility-weighted, T1 dynamic, diffusion, functional, and diffusion tensor imaging.

Recent advances in neuroendocrine imaging.

PURPOSE OF REVIEW: Imaging is a critical component of both neuroendocrine lesion identification and anatomic delineation for treatment planning. Cross-sectional and isotopic-based physiologic imaging techniques have, to date, been the radiological modalities of choice. This review focuses on recent advances in imaging that are related to the evaluation of neuroendocrine abnormalities, in particular advances in MRI. RECENT FINDINGS: Magnetic-resonance perfusion examination of tissue characteristics in the pituitary, adrenal and thyroid glands indicates that, in many cases, adenomas of these glands have distinguishable hemodynamic characteristics relative to the parenchyma of the gland as a whole and to other lesions. Moreover, perfusion metrics might provide a basis for evaluating response to therapy (in the pituitary) and delineation of lesions in the adrenal and thyroid glands. Anisotropy-based imaging techniques show promise in providing direct, relevant information about pituitary tumor involvement of the adjacent cavernous sinuses. SUMMARY: The most recent methodological advances in the imaging of neuroendocrine disorder involves the continued development and application of MRI, in particular using pulse sequences, which provide a greater insight into the internal structure and physiology of the tissues interrogated, relative to standard sequences.

Quantitative approaches to functional MRI: applications in epilepsy.

The application of functional magnetic resonance imaging (fMRI) to elucidation of seizures and epilepsy has been built primarily upon a framework derived from cortical responses to periodic sensory (and cognitive) stimuli. This analytical approach relies upon assumptions that may be less applicable to the problem of seizure origination. Because of the heterogeneous and complex nature of seizures, a number of quantitative methodologies have been derived to understand fMRI changes that are associated with epileptiform neural activity. Separated broadly, these can be divided into those making some set of assumptions about the form of the MRI signal response to neural activation (the general linear model), and those that are data driven. It is likely that a combination of methodologies, where data driven methods are "informed" by knowledge of the underlying neurobiological process will provide the greatest insight into the underlying neurobiological basis of seizure origination.