K. Schwab

CONTRAST EXTRAVASATION ON CT ANGIOGRAPHY PREDICTS HEMATOMA EXPANSION IN INTRACEREBRAL HEMORRHAGE

Background: Patients with acute intracerebral hemorrhage (ICH) presenting within 3 hours of symptom onset are known to be at increased risk of expansion. However, only a minority arrive within this time frame. Therefore, alternative markers for expansion risk are needed. Objective: To examine whether contrast extravasation on CT angiography (CTA) at presentation predicts subsequent hematoma expansion. Methods: Consecutive patients with primary ICH presenting to an urban tertiary care hospital were prospectively captured in a database. We retrospectively reviewed images for all patients receiving a CTA and at least one further CT scan within 48 hours. Results: Complete data were available for 104 patients. Contrast extravasation at the time of CTA was present in 56% of patients, and associated with an increased risk of hematoma expansion (22% vs 2%, p = 0.003). Patients who received a baseline CTA within 3 hours were more likely to have subsequent expansion (27%, vs 13% for those presenting later, p = 0.1). However, after multivariable analysis, contrast extravasation was the only significant predictor of hematoma expansion (OR 18, 95% CI 2.1 to 162). This effect was independent of time to presentation. Conclusions: Contrast extravasation is independently associated with hematoma expansion. Patients presenting within the first few hours after symptom onset have traditionally been considered those at highest risk of expansion. However, for those presenting later, the presence of contrast may be a useful marker to guide therapies aimed at decreasing this risk.

Predicting sites of new hemorrhage with amyloid imaging in cerebral amyloid angiopathy

Objective: We aimed to determine whether amyloid imaging can help predict the location and number of future hemorrhages in cerebral amyloid angiopathy (CAA). Methods: We performed a longitudinal cohort study of 11 patients with CAA without dementia who underwent serial brain MRIs after baseline amyloid imaging with Pittsburgh compound B (PiB). Mean distribution volume ratio (DVR) of PiB was determined at the sites of new micro/macrobleeds identified on follow-up MRI and compared with PiB retention at “simulated” hemorrhages, randomly placed in the same subjects using a probability distribution map of CAA-hemorrhage location. Mean PiB retention at the sites of observed new bleeds was also compared to that in shells concentrically surrounding the bleeds. Finally the association between number of incident bleeds and 3 regional amyloid measures were obtained. Results: Nine of 11 subjects had at least one new microbleed on follow-up MRI (median 4, interquartile range [IQR] 1–9) and 2 had 5 new intracerebral hemorrhages. Mean DVR was greater at the sites of incident bleeds (1.34, 95% confidence interval [CI] 1.23–1.46) than simulated lesions (1.14, 95% CI 1.07–1.22, p < 0.0001) in multivariable models. PiB retention decreased with increasing distance from sites of observed bleeds (p < 0.0001). Mean DVR in a superior frontal/parasagittal region of interest correlated independently with number of future hemorrhages after adjustment for relevant covariates (p = 0.003). Conclusions: Our results provide direct evidence that new CAA-related hemorrhages occur preferentially at sites of increased amyloid deposition and suggest that PiB-PET imaging may be a useful tool in prediction of incident hemorrhages in patients with CAA.

Statin use and outcome after intracerebral hemorrhage Case-control study and meta-analysis

Objectives: Intracerebral hemorrhage (ICH) is a highly lethal disease of the elderly. Use of statins is increasingly widespread among the elderly, and therefore common in patients who develop ICH. Accumulating data suggests that statins have neuroprotective effects, but their association with ICH outcome has been inconsistent. We therefore performed a meta-analysis of all available evidence, including unpublished data from our own institution, to determine whether statin exposure is protective for patients who develop ICH. Methods: In our prospectively ascertained cohort, we compared 90-day functional outcome in 238 pre-ICH statin cases and 461 statin-free ICH cases. We then meta-analyzed results from our cohort along with previously published studies using a random effects model, for a total of 698 ICH statin cases and 1,823 non–statin-exposed subjects. Results: Data from our center demonstrated an association between statin use before ICH and increased probability of favorable outcome (odds ratio [OR] = 2.08, 95% confidence interval [CI] 1.37–3.17) and reduced mortality (OR = 0.47, 95% CI 0.32–0.70) at 90 days. No compound-specific statin effect was identified. Meta-analysis of all published evidence confirmed the effect of statin use on good outcome (OR = 1.91, 95% CI 1.38–2.65) and mortality (OR = 0.55, 95% CI 0.42–0.72) after ICH. Conclusion: Antecedent use of statins prior to ICH is associated with favorable outcome and reduced mortality after ICH. This phenomenon appears to be a class effect of statins. Further studies are required to clarify the biological mechanisms underlying these observations.

Warfarin-related intraventricular hemorrhage: Imaging and outcome

Objective: Oral anticoagulation therapy (OAT) with warfarin increases mortality and disability after intracerebral hemorrhage (ICH), the result of increased ICH volume and risk of hematoma expansion. We investigated whether OAT also influences risk of development of intraventricular hemorrhage (IVH), the volume of IVH and IVH expansion, and whether IVH is a substantive mediator of the overall effect of OAT on ICH outcome. Methods: We performed a retrospective analysis of a prospectively collected single-center cohort of 1,879 consecutive ICH cases (796 lobar, 865 deep, 153 cerebellar, 15 multiple location, 50 primary IVH) from 1999 to 2009. ICH and IVH volumes at presentation, as well as hematoma expansion (>33% or >6 mL increase) and IVH expansion (>2 mL increase), were determined using established semiautomated methods. Outcome was assessed at 90 days using either the modified Rankin Scale or Glasgow Outcome Scale. Results: Warfarin use was associated with IVH risk, IVH volume at presentation, and IVH expansion in both lobar and deep ICH (all p < 0.05) in a dose-response relationship with international normalized ratio. Warfarin was associated with poor outcome in both lobar and deep ICH (p < 0.01), and >95% of this effect was accounted for by baseline ICH and IVH volumes, as well as ICH and IVH expansion. Conclusion: Warfarin increases IVH volume and risk of IVH expansion in lobar and deep ICH. These findings (along with effects on ICH volume and expansion) likely represent the mechanisms by which anticoagulation worsens ICH functional outcome.

Interrelationship of superficial siderosis and microbleeds in cerebral amyloid angiopathy.

Objective: We sought to explore the mechanisms leading to cerebral amyloid angiopathy (CAA)-related cortical superficial siderosis (cSS) by examining its neuroimaging and genetic association with cerebral microbleeds (CMBs). Methods: MRI scans of 84 subjects with probable or definite CAA participating in a longitudinal research study were graded for cSS presence and severity (focal, restricted to ≤3 sulci vs disseminated, ≥4 sulci), and CMB count. APOE ε variants were directly genotyped. We performed cross-sectional analysis comparing CMB counts and APOE ε2 and ε4 allele frequency between subjects with no, focal, or disseminated cSS. Results: cSS was present in 48% (n = 40) of the population. APOE ε2 was overrepresented among participants with focal (odds ratio [OR] 7.0, 95% confidence interval [CI] 1.7–29.3, p = 0.008) and disseminated (OR 11.5, 95% CI 2.8–46.2, p = 0.001) cSS relative to individuals without cSS. CMB counts decreased with increasing severity of cSS (median: 41, 38, and 15 for no cSS, focal cSS, and disseminated cSS, respectively, p = 0.09). The highest CMB count tertile was associated with APOE ε4 (OR 3.0, 95% CI 1.4–6.6, p = 0.006) relative to the lowest tertile. Conclusions: Among individuals with advanced CAA, cSS tends to occur in individuals with relatively lower CMB counts and with a distinct pattern of APOE genotypes. These results suggest that CAA-related cSS and CMBs may arise from distinct vasculopathic mechanisms.

Effect of CTA Tube Current on Spot Sign Detection and Accuracy for Prediction of Intracerebral Hemorrhage Expansion

BACKGROUND AND PURPOSE: Reduction of CT tube current is an effective strategy to minimize radiation load. However, tube current is also a major determinant of image quality. We investigated the impact of CTA tube current on spot sign detection and diagnostic performance for intracerebral hemorrhage expansion. MATERIALS AND METHODS: We retrospectively analyzed a prospectively collected cohort of consecutive patients with primary intracerebral hemorrhage from January 2001 to April 2015 who underwent CTA. The study population was divided into 2 groups according to the median CTA tube current level: low current (<350 mA) and high current (≥350 mA). CTA first-pass readings for spot sign presence were independently analyzed by 2 readers. Baseline and follow-up hematoma volumes were assessed by semiautomated computer-assisted volumetric analysis. Sensitivity, specificity, positive and negative predictive values, and accuracy of spot sign in predicting hematoma expansion were calculated. RESULTS: This study included 709 patients (288 and 421 in the low- and high-current groups, respectively). A higher proportion of low-current scans identified at least 1 spot sign (20.8% versus 14.7%, P = .034), but hematoma expansion frequency was similar in the 2 groups (18.4% versus 16.2%, P = .434). Sensitivity and positive and negative predictive values were not significantly different between the 2 groups. Conversely, high-current scans showed superior specificity (91% versus 84%, P = .015) and overall accuracy (84% versus 77%, P = .038). CONCLUSIONS: CTA obtained at high levels of tube current showed better diagnostic accuracy for prediction of hematoma expansion by using spot sign. These findings may have implications for future studies using the CTA spot sign to predict hematoma expansion for clinical trials.