Added Value of High-b-Value (b=3000 s/mm(2)) Diffusion-Weighted Imaging at 3 T in Relation to Fluid-Attenuated Inversion Recovery Images for the Evaluation of Cortical Lesions in Inflammatory Brain Diseases

作者：Iwashita Koya; Hirai Toshinori^*; Kitajima Mika; Shigematsu Yoshinori; Uetani Hiroyuki; Iryo Yasuhiko; Azuma Minako; Hayashida Eri; Ando Yukio; Murakami Ryuji; Yamashita Yasuyuki

来源：Journal of Computer Assisted Tomography, 2013, 37(3): 338-342.

DOI：10.1097/RCT.0b013e318288a661

• MRI
• 3 T
• high b value
• diffusion-weighted imaging
• encephalitis

Objective: The purpose of this study was to determine how the gray-to-white matter contrast in healthy subjects changes on high-b-value diffusion-weighted imaging (DWI) acquired at 3 T and evaluate whether high-b-value DWI at 3 T is useful for the detection of cortical lesions in inflammatory brain diseases. %26lt;br%26gt;Methods: Ten healthy volunteers underwent DWI at b = 1000, 2000, 3000, 4000, and 5000 s/mm(2) on a 3-T MRI unit. On DW images, 1 radiologist performed region-of-interest measurements of the signal intensity of 8 gray matter structures. The gray-to-white matter contrast ratio (GWCR) was calculated. Ten patients with inflammatory cortical lesions were also included. All patients underwent conventional MRI and DWI at b = 1000 and 3000 s/mm(2). Using a 4-point grading system, 2 radiologists independently assessed the presence of additional information on DW images compared with fluid-attenuated inversion recovery images. Interobserver agreement was assessed by kappa statistics. %26lt;br%26gt;Results: In the healthy subjects, the b value increased as the GWCR decreased in all evaluated gray matter structures. On DW images acquired at b = 3000 s/mm(2), mean GWCR was less than 1.0 in 7 of 8 structures. For both reviewers, DWI at b = 3000 s/mm(2) yielded significantly more additional information than did DWI at b = 1000 s/mm(2) (P %26lt; 0.05). Interobserver agreement for DWI at b = 1000 s/mm(2) and b = 3000 s/mm(2) was fair (kappa = 0.35) and excellent (kappa = 1.0), respectively. %26lt;br%26gt;Conclusions: At 3-T DWI, the gray-to-white matter contrast in most gray matter structures reverses at b = 3000 s/mm(2). In the evaluation of cortical lesions in patients with inflammatory brain diseases, 3-T DWI at b = 3000 s/mm(2) was more useful than b = 1000 s/mm(2).

• 出版日期2013-6