VLCBV and Hemorrhagic Transformation
Regional very low cerebral blood volume predicts hemorrhagic transformation better than diffusion-weighted imaging volume and thresholded apparent diffusion coefficient in acute ischemic stroke.
Campbell BC, Christensen S, Butcher KS, Gordon I, Parsons MW, Desmond PM, Barber PA, Levi CR, Bladin CF, De Silva DA, Donnan GA, Davis SM; EPITHET Investigators.Department of Neurology, Royal Melbourne Hospital, Grattan Street, Parkville VIC 3050, Australia.Preliminary studies have suggested that very low cerebral blood volume (VLCBV) predicts HT. We compared HT prediction by VLCBV and DWI using data from the EPITHET study.
METHODS:Normal-percentile CBV values were calculated from the nonstroke hemisphere. Whole-brain masks with CBV thresholds of the <0, 2.5, 5, and 10th percentiles were created. The volume of tissue with VLCBV was calculated within the acute DWI ischemic lesion. HT was graded as per ECASS criteria.
RESULTS:HT occurred in 44 of 91 patients. Parenchymal hematoma (PH) occurred in 13 (4 symptomatic) and asymptomatic hemorrhagic infarction (HI) in 31. The median volume of VLCBV was significantly higher in cases with PH. VLCBV predicted HT better than DWI lesion volume and thresholded apparent diffusion coefficient lesion volume in receiver operating characteristic analysis and logistic regression.A cutpoint at 2 mL VLCBV with the <2.5th percentile had 100% sensitivity for PH and, in patients treated with tissue plasminogen activator, defined a population with a 43% risk of PH (95% CI, 23% to 66%, likelihood ratio=16). VLCBV remained an independent predictor of PH in multivariate analysis with traditional clinical risk factors for HT.
CONCLUSIONS:VLCBV predicted HT after thrombolysis better than did DWI. Prediction was better in patients who recanalized. If validated in an independent cohort, the addition of VLCBV to prethrombolysis decision making may reduce the incidence of HT.
Markedly reduced apparent blood volume on bolus contrast magnetic resonance imaging as a predictor of hemorrhage after thrombolytic therapy for acute ischemic stroke.
Alsop DC, Makovetskaya E, Kumar S, Selim M, Schlaug G.Stroke. 2005 Apr;36(4):746-50. Epub 2005 Mar 3.Department of Radiology, Beth Israel Deaconess Medical CenterThis study sought to define characteristics of hemodynamic magnetic resonance imaging (MRI), which best predict hemorrhage.METHODS:Bolus contrast and diffusion MRI were performed before IV-tPA in 20 patients within the first 6 hours after symptom onset. Hemorrhage was assessed on follow-up MRI (n=15) and computed tomography (n=5) scans.
RESULTS:Of the 20 patients studied, 5 had detectable hemorrhage on follow-up scans. Blood volume maps demonstrated virtually no signal within much of the hemorrhagic region, indicating contrast did not arrive by the end of the imaging series (80 seconds). Within the hemodynamically abnormal region, a threshold of at least 126 voxels with blood volume <5% separated hemorrhagic with a sensitivity of 100% and a specificity of 73% (P<0.01). All subjects with hemorrhage were at least partially reperfused after thrombolysis, whereas most false-positives did not reperfuse (P<0.05). The number of low blood volume voxels within individual patients correlated with the number of voxels with apparent diffusion coefficient values <550x10(-6) mm2/s (P<0.019), another previously proposed predictor of hemorrhage.
CONCLUSIONS:Extremely low or completely absent contrast arrival may indicate tissue-at-risk for hemorrhage.