Richard E. Burgess

Predictors of highly prevalent brain ischemia in intracerebral hemorrhage

This study was undertaken to determine the prevalence, characteristics, risk factors, and temporal profile of concurrent ischemic lesions in patients with acute primary intracerebral hemorrhage (ICH).

Racial differences in microbleed prevalence in primary intracerebral hemorrhage

Background: Primary intracerebral hemorrhage is two to three times more common in many racial populations, including black patients. Previous studies have shown that microbleeds, identified on gradient echo MRI (GRE), are present in 50–80% of patients with primary ICH. The objective of this study was to compare, by race, the rates, risk factors, and topography of microbleeds in patients hospitalized for primary ICH. Methods: Patients diagnosed with primary ICH at two metropolitan stroke centers were included. Clinical and neuroimaging data were recorded for each patient. Analyses were performed to compare baseline characteristics as well as imaging findings by race. Results: A total of 87 patients met inclusion criteria (42 black subjects, 45 white subjects). The black cohort was younger (p < 0.001), and had a greater rate of hypertension (p = 0.001), but not other vascular risk factors. Microbleeds were more prevalent in the black population, with 74% of blacks having one or more microbleeds compared to 42% of whites (p = 0.005). The black population also tended to have a greater frequency of microbleeds in multiple territories than the white population (38% vs 22%, p = 0.106). When adjusting for age, hypertension, and alcohol use, race was an independent predictor of microbleeds (OR 3.308, 95% CI 1.144–9.571, p = 0.027). Conclusions: These pilot data suggest that significant racial differences exist in the frequency and topography of microbleeds in patients with primary ICH. Microbleeds may be an important emerging imaging biomarker with the potential to provide insights into ICH pathophysiology, prognosis, and disease progression, as well as possible therapeutic strategies, particularly in medically underserved populations.

Association of Chronic Kidney Disease With Cerebral Microbleeds in Patients With Primary Intracerebral Hemorrhage

Background and Purpose— To investigate the relationship between chronic kidney disease (CKD) and MRI-defined cerebral microbleeds (CMB), a harbinger of future intracerebral hemorrhage (ICH), among patients with a recent history of primary ICH. Methods— Using data from a predominantly black cohort of patients with a recent ICH-enrolled in an observational study between September 2007 and June 2011, we evaluated the association between CKD (defined as estimated low glomerular filtration rate<60 mL/min per 1.73 m2) and CMB on gradient-echo MRI. Multivariable models were generated to determine the contribution of CKD to the presence, number, and location of CMB. Results— Of 197 subjects with imaging data, mean age was 59 years, 48% were women, 73% were black, 114 (58%) had ≥1 CMBs, and 52 (26%) had CKD. Overall, CKD was associated with presence of CMB (adjusted odds ratio, 2.70; 95% confidence interval [CI], 1.10–6.59) and number of CMB (adjusted relative risk, 2.04; 95% CI, 1.27–3.27). CKD was associated with CMB presence (adjusted odds ratio, 3.44; 95% CI, 1.64–7.24) and number (adjusted relative risk, 2.46; 95% CI, 1.11–5.42) in black patients, but not CMB presence (adjusted odds ratio, 3.00; 95% CI, 0.61–14.86) or number (adjusted relative risk, 1.03; 95% CI: 0.22–4.89) in non-Hispanic white patients (interactions by race were statistically not significant). Conclusions— CKD is associated with a greater presence and number of CMB in ICH patients, particularly in patients of black race. Future studies should assess whether low estimated glomerular filtration rate may be a CMB risk marker or potential therapeutic target for mitigating the development of CMB.

Development and Validation of a Simple Conversion Model for Comparison of Intracerebral Hemorrhage Volumes Measured on CT and Gradient Recalled Echo MRI

Background and Purpose— Gradient recalled echo MRI (GRE) has been shown to be as accurate as CT for the detection of acute intracerebral hemorrhage (ICH). However, because of the differences in the signal parameter being detected, apparent hemorrhage size is expected to vary by imaging modality, with GRE providing larger volumes attributable to susceptibility effects. Methods— Image data from patients participating in 3 ICH studies were retrospectively reviewed. Patients with acute ICH were included if (1) concurrent MRI and CT were performed within 72 hours of symptom onset, and (2) each modality was performed within 240 minutes of each other. ICH volumes were calculated using a semiautomated image analysis program. The least squares method was used to develop a conversion equation based on a linear regression of GRE volume on CT volume. Results— Thirty-six patients met inclusion criteria. MRI was performed first in 18, CT first in 18. Mean hemorrhage volume was 25.2cc (range 0.1 to 83.9cc) on CT and 32.7cc (range 0.1 to 98.7cc) measured on GRE. A linear relationship defined by CT Volume=GRE Volume*0.8 (Spearman’s correlation coefficient=0.992, P<0.001) was derived. Conclusions— Acute ICH volumes as measured on GRE pulse sequences are consistently larger than CT volumes. A simple mathematical conversion model has been developed: CT volume=0.8*GRE volume. This formula can be used in studies using both imaging modalities, across different studies, or to track ICH growth over time independent of imaging modality in an individual patient.

Hyperacute injury marker (HARM) in primary hemorrhage: A distinct form of CNS barrier disruption

Objective: The objective of the study was to characterize a previously unreported form of CNS barrier disruption in intracerebral hemorrhage (ICH): hyperacute injury marker (HARM). Methods: In this retrospective cohort analysis of patients presenting with primary ICH, precontrast and postcontrast MRI scans obtained within 5 days of symptom onset were analyzed. The presence of CNS barrier disruption was defined by 1) perihematomal or intrahematomal enhancement visualized on postcontrast T1-weighted MRI or 2) HARM: sulcal or ventricular hyperintensity visualized on postcontrast fluid-attenuated inversion recovery sequences (graded on a 5-point scale). Results: Forty-six patients were included in the analysis. Mean age was 65 years, median NIH Stroke Scale score was 7, and mean ICH volume was 12.2 mL (range 0.3–46.9 mL). HARM was visualized in 85% of patients, and this was moderate to severe in 50%. In all cases, the sulcal enhancement was noncontiguous with the hematoma. Of those patients with postcontrast T1-weighted imaging, perihematomal or intrahematomal contrast enhancement was visualized in 75% of patients. Conclusions: This study demonstrates that HARM occurs in intracerebral hemorrhage and that it likely represents a second type of CNS barrier disruption distinct from parenchymal postcontrast T1-weighted enhancement. Similar to T1 enhancement, this phenomenon may serve as a clinically useful biomarker to test therapies aimed at stabilizing acute ICH and CNS barrier disruption. Future studies are needed to further define the time course and prognostic implications of this finding.

Poor Long-Term Blood Pressure Control After Intracerebral Hemorrhage

Background and Purpose— Hypertension is the most important risk factor associated with intracerebral hemorrhage. We explored racial differences in blood pressure (BP) control after intracerebral hemorrhage and assessed predictors of BP control at presentation, 30 days, and 1 year in a prospective cohort study. Methods— Subjects with spontaneous intracerebral hemorrhage were identified from the DiffErenCes in the Imaging of Primary Hemorrhage based on Ethnicity or Race (DECIPHER) Project. BP was compared by race at each time point. Multivariable linear regression was used to determine predictors of presenting mean arterial pressure, and longitudinal linear regression was used to assess predictors of mean arterial pressure at follow-up. Results— A total of 162 patients were included (mean age, 59 years; 53% male; 77% black). Mean arterial pressure at presentation was 9.6 mm Hg higher in blacks than whites despite adjustment for confounders (P=0.065). Fewer than 20% of patients had normal BP (<120/80 mm Hg) at 30 days or 1 year. Although there was no difference at 30 days (P=0.331), blacks were more likely than whites to have Stage I/II hypertension at 1 year (P=0.036). Factors associated with lower mean arterial pressure at follow-up in multivariable analysis were being married at baseline (P=0.032) and living in a facility (versus personal residence) at the time of BP measurement (P=0.023). Conclusions— Long-term BP control is inadequate in patients after intracerebral hemorrhage, particularly in blacks. Further studies are needed to understand the role of social support and barriers to control to identify optimal approaches to improve BP in this high-risk population.

Multiple auras Clinical significance and pathophysiology

Background: Patients with partial epilepsy may report multiple types of aura during their seizures. The significance of the occurrence of multiple auras in the same patient is not known. Methods: The clinical and electrophysiologic characteristics of patients with more than one aura type (abdominal, auditory, autonomic, gustatory, olfactory, psychic, somatosensory, and visual auras), evaluated in the Cleveland Clinic epilepsy monitoring unit between 1989 and 2005, were studied. Results: Thirty-one patients experienced multiple aura types during a seizure. Ninety percent of patients with at least two aura types (n = 31) and 100% percent of patients with at least three aura types (n = 12) had seizures arising from the right/nondominant hemisphere. EEG seizures remained restricted in all patients during their auras. Twenty patients had epilepsy surgery with seizure freedom in 53%. Subdural EEG recordings in six patients showed either a march of sequential auras, or in one case, several ictal onset zones resulting in separate isolated auras. Ictal SPECT in six patients with right-sided seizures showed a lack of activation in brainstem structures. Conclusions: Most patients who report multiple aura types have localized epilepsy in the nondominant hemisphere, and are good surgical candidates. A common mechanism for multiple auras may be a spreading but restricted EEG seizure activating sequential symptomatogenic zones, but without the ictal activation of deeper structures or contralateral spread to cause loss of awareness and amnesia for the auras.

Racial Differences by Ischemic Stroke Subtype: A Comprehensive Diagnostic Approach

Background. Previous studies have suggested that black populations have more small-vessel and fewer cardioembolic strokes. We sought to analyze racial differences in ischemic stroke subtype employing a comprehensive diagnostic workup with magnetic resonance-imaging-(MRI-) based evaluation including diffusion-weighted imaging (DWI). Methods. 350 acute ischemic stroke patients admitted to an urban hospital with standardized comprehensive diagnostic evaluations were retrospectively analyzed. Ischemic stroke subtype was determined by three Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification systems. Results. We found similar proportions of cardioembolic and lacunar strokes in the black and white cohort. The only subtype category with a significant difference by race was “stroke of other etiology,” more common in whites. Black stroke patients were more likely to have an incomplete evaluation, but this did not reach significance. Conclusions. We found similar proportions by race of cardioembolic and lacunar strokes when employing a full diagnostic evaluation including DWI MRI. The relatively high rate of cardioembolism may have been underappreciated in black stroke patients when employing a CT approach to stroke subtype diagnosis. Further research is required to better understand the racial differences in frequency of “stroke of other etiology” and explore disparities in the extent of diagnostic evaluations.