Ultra-long-TE arterial spin labeling reveals rapid and brain-wide blood-to-CSF water transport in humans

The study of brain clearance mechanisms is an active area of research. While we know that the cerebrospinal fluid (CSF) plays a central role in one of the main existing clearance pathways, the exact processes for the secretion of CSF and the removal of waste products from tissue are under debate. CSF is thought to be created by the exchange of water and ions from the blood, which is believed to mainly occur in the choroid plexus. This exchange has not been thoroughly studied in vivo. We propose a modified arterial spin labeling (ASL) MRI sequence and image analysis to track blood water as it is transported to the CSF, and to characterize its exchange from blood to CSF. We acquired six pseudo-continuous ASL sequences with varying labeling duration (LD) and post-labeling delay (PLD) and a segmented 3D-GRASE readout with a long echo train (8 echo times (TE)) which allowed separation of the very long-T2 CSF signal. ASL signal was observed at long TEs (793 ms and higher), indicating presence of labeled water transported from blood to CSF. This signal appeared both in the CSF proximal to the choroid plexus and in the subarachnoid space surrounding the cortex. ASL signal was separated into its blood, gray matter and CSF components by fitting a triexponential function with T2s taken from literature. A two-compartment dynamic model was introduced to describe the exchange of water through time and TE. From this, a water exchange time from the blood to the CSF (Tbl->CSF) was mapped, with an order of magnitude of approximately 60 s

BG-12 reduces evolution of new enhancing lesions to T1-hypointense lesions in patients with multiple sclerosis

BG-12, an immunomodulatory agent, reduces frequency of new gadolinium-enhancing (Gd+) lesions in relapsing multiple sclerosis (MS). This study reports the effect of 240 mg BG-12 orally three times daily (tid) for 24 weeks on the evolution of new Gd+ lesions to T1-hypointense lesions. Brain magnetic resonance imaging (MRI) scans from patients in placebo and 240 mg BG-12 tid arms of a phase 2b study were examined retrospectively. Included patients had at least one new Gd+ lesion from weeks 4 to 12. Week 24 scans were analyzed for number and proportion of new Gd+ lesions that evolved to T1-hypointense lesions. Eighteen patients receiving BG-12 and 38 patients receiving placebo were included in the analysis. The analysis tracked 147 new Gd+ lesions in patients from the BG-12 group and 221 Gd+ lesions in patients from the placebo group. The percentage of Gd+ lesions that evolved to T1-hypointense lesions was 34% lower with BG-12 treatment versus placebo (29%, BG-12; 44%, placebo; odds ratio 0.51; 95% confidence interval 0.43, 0.61; p > 0.0001). In addition to reducing frequency of new Gd+ lesions, BG-12 significantly reduced probability of their evolution to T1-hypointense lesions in patients with MS compared with placebo

Treatment of Intracranial Superfi cial Micro-AVMs: A Single Center Experience

Background: Surgery and embolization may both be considered in ruptured superficial micro-AVMs. However, surgery may be challenged by poor recognition of the lesion and embolization by difficulty in achieving complete obliteration and avoiding en passage feeders. Recent developments in AVM surgery and embolization techniques call for a reevaluation of these treatment options.Methods: Eight consecutive patients with superficial micro-AVMs are presented. All patients received an initial embolization attempt with either nBCA or ONYX. If complete obliteration was not obtained, either a second embolization or surgical resection was offered. At surgery, indocyanine green video angiography (ICG-VA) was used in all cases. Effectiveness and safety of all procedures were evaluated retrospectively. Functional outcome at 6 months was assessed by the modified Ranking Score (mRS).Results: Patients had a mean age of 52±17 years and all presented with hemorrhage. The mean nidus size was 4 mm, and was localized supratentorially in 5 cases and infratentorially in 3. Initial embolization was successful in 2 patients (25%). One patient underwent a second, unsuccessful, embolization attempt and 1 patient did not receive further treatment. Consequently, five patients underwent surgery, which was successful in four (80%). The unsuccessful case was successfully reoperated. The only two procedural complications were related to superselective embolization, but neither caused clinical sequelae. Mean clinical follow-up was 29 months (range, 4–75mo), with mRS 0 in 2, mRS 1 in 4 and mRS 3 in 2 cases.Conclusions: In a current case series, embolization of superficial micro-AVMs was associated with a lower success rate (25% vs 80%) than microsurgery and a higher procedural complication rate (minor complications: 22% vs 0%).</p

Association between MRI parameters and the MS severity scale: a 12 year follow-up study

Contains fulltext : 80250.pdf (publisher's version ) (Closed access)BACKGROUND: Several magnetic resonance imaging (MRI) parameters are known to be associated with short-term outcome in multiple sclerosis (MS) patients. MS-related disability typically progresses over decades, stressing the need for longer follow-up studies. Until now, these studies are relatively sparse and, therefore, the predictive value of MRI parameters for clinical disability remains largely unknown. OBJECTIVE: To assess the predictive value of brain MRI parameters, which are obtained during the first 3.3 years of the study for overall disease severity as measured by the MS Severity Score (MSSS) after 12.2 years follow-up. METHODS: Forty-six MS patients were included in the study. MRI parameters included both lesion loads and atrophy measures. Average and change parameters were calculated for MRI parameters and subsequently used as independent variables in regression models, while MSSS was the dependent variable. RESULTS: Follow-up (FU) was obtained in 43/46 patients (94%) and median expanded disability status scale (EDSS) score increased significantly from 2.5 to 4.0. At last FU median MSSS was 4.3 (range 2.2-6.9). In univariate analyses, both change and cross-sectional T1-hypointense lesion load and ventricular atrophy measures were associated with MSSS. A multiple regression model included the change parameter of hypointense T1-lesion load (BHLL). This model explained 20% of variance in MSSS, which increased to 34% when type of disease (relapsing remitting or secondary progressive), age, and sex were entered additionally. CONCLUSION: MRI measures of axonal loss are associated with higher overall disease severity in MS patients