Whole Brain Quantitative CBF, CBV, and MTT Measurements Using MRI Bolus Tracking: Implementation and Application to Data Acquired From Hyperacute Stroke Patients

Abstract

A robust whole brain magnetic resonance (MR) bolus tracking technique based on indicator dilution theory, which could quantitatively calculate cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) on a regional basis, was developed and tested. T2*-weighted gradient-echo echoplanar imaging (EPI) volumes were acquired on 40 hyperacute stroke patients after gadolinium diethylene triamine pentaacetic acid (Gd-DTPA) bolus injection. The thalamus, white matter (WM), infarcted area, penumbra, and mirror infarcted and penumbra regions were analyzed. The calculation of the arterial input function (AIF) needed for absolute quantification of CBF, CBV, and MTT was shown to be user independent. The CBF values (ml/min/100 g units) and CBV values (% units, in parentheses) for the thalamus, WM, infarct, mirror infarct, penumbra, and mirror penumbra (averaged over all patients) were 69.8 ± 22.2 (9.0 ± 3.0 SD); 28.1 ± 6.9 (3.9 ± 1.2); 34.4 ± 22.4 (7.1 ± 2.7); 60.3 ± 20.7 (8.2 ± 2.3); 50.2 ± 17.5 (10.4 ± 2.4); and 64.2 ± 17.0 (9.5 ± 2.3), respectively, and the corresponding MTT values (in seconds) were 8.0 ± 2.1; 8.6 ± 3.0; 16.1 ± 8.9; 8.6 ± 2.9; 13.3 ± 3.5; and 9.4 ± 3.2. The infarct and penumbra CBV values were not significantly different from their corresponding mirror values, whereas the CBF and MTT values were (P < 0.01). Quantitative measurements of CBF, CBV, and MTT were calculated on a regional basis on data acquired from hyperacute stroke patients, and the CBF and MTT values showed greater sensitivity to areas with perfusion defects than the CBV values. (C) 2000 Wiley-Liss, Inc.