Comparison of diffusion-weighted imaging between high and standard b-values for primary central nervous system lymphoma

Abstract

To investigate the utility of diffusion-weighted (DW) magnetic resonance imaging (MRI) with a high b-value (b = 3000 s/mm(2)) compared with standard b-value (b = 1000 s/mm(2)) DW imaging in patients with primary central nervous system lymphoma (PCNSL). High and standard b-value (b = 3000 and 1000 s/mm(2), respectively) DW images were acquired in 15 patients with PCNSL. The number and location of the lesions were assessed. MRI signal intensities (SIs), signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), contrast ratios (CRs), and apparent diffusion coefficients (ADCs) of the lesions and normal parenchyma were measured. Thirty-two lesions in 15 patients were revealed. Twenty-seven of the lesions were hyperintense at DW MRI with high and standard b-values; high b-value images revealed five additional lesions. Lesions were also more conspicuous at high b-value (b = 3000 s/mm(2)) DW MRI compared to standard b-value images (b = 1000 s/mm(2)). SNR, CNR, and ADC values in lesions and normal parenchyma were lower in the b = 3000 s/mm(2) images compared to the b = 1000 s/mm(2) images (SNR: 250.7 ± 124.7 versus 112.3 ± 68.7; CNR: 83.4 ± 74.7 versus 59.6 ± 60.4, b = 1000 and 3000 s/mm(2), respectively). The CR was significantly greater in the b = 3000 s/mm(2) images compared to the b = 1000 s/mm(2) images (CR: 0.28 ± 0.13 versus 0.18 ± 0.10). Although quantitative analyses revealed higher SI, SNR, and CNR values in standard b-value (b = 1000 s/mm(2)) DW images, higher b-value imaging could be beneficial for detecting additional lesions and improving the contrast between lesions and normal tissue in patients with PCNSL.