A Comparison of Mean Displacement Values Using High b-Value Q-Space Diffusion-weighted MRI with Conventional Apparent Diffusion Coefficients in Patients with Stroke

Rationale and Objectives: Q-space analysis using high b-value diffusion-weighted magnetic resonance (MR) data provides information on tissue microstructure in contrast to conventional MR imaging (MRI) based on low b-value diffusion-weighted imaging (DWI). The purpose of this study was to evaluate the use of mean displacement (MDP) map in stroke patients using q-space diffusion-weighted MRI (QSI). Materials and Methods: Twenty-one patients presenting with a total of 22 acute or subacute cerebral infarctions were included. MR protocol consisted of conventional MR sequences, DWI (b-value; 1000 s/mm(2)) and QSI (b-value; maximum 12,000 s/mm2). Apparent diffusion coefficient (ADC) maps of conventional DWI and MOP maps of QSI data were obtained and compared in the ischemic lesions and corresponding normal tissues. Results: Decreased ADC values were present in all lesions. There was no correlation between ADC and MOP values in the lesions (r = 0.21). MOP values of the lesions were 8.60 +/- 1.26 pm (mean +/- SD). Most of the lesions (16/22) had higher MOP values than normal brain tissue. Three lesions showed lower MOP values and three showed mixed MOP values. Conclusions: The MOP maps using QSI data provides additional information for stroke patients compared to conventional DWI.