Detection of mural inflammation with low b-value diffusion-weighted imaging in patients with active Takayasu Arteritis.

OBJECTIVES To evaluate the performance of low b-value diffusion-weighted imaging (DWI) for detection of inflamed vessels in active Takayasu arteritis (TA). METHODS Forty patients with active TA involving the thoracic aorta and its super-aortic branches underwent low b-value (50 s/mm2) DWI, T2-weighted imaging (T2WI), and delayed enhancement T1-weighted imaging (DEI). Corresponding images on these 3 sequences at the same diseased level were evaluated qualitatively and quantitatively using Friedman and Kruskal-Wallis test, and the agreement between them in detection of inflamed vessels was assessed using Cochran's Q test. RESULTS The overall image quality of DEI, DWI, and T2WI was scored 7.97 ± 1.15, 7.32 ± 1.73, and 6.51 ± 1.69 respectively. The score of DEI and DWI was higher than that of T2WI (p 0.99). CONCLUSIONS Low b-value DWI may be used as a promising alternative to DEI for detecting inflamed vessels in active TA. KEY POINTS • Currently, the most widely used imaging modality in detection of mural inflammation is contrast-enhanced MRI. • Low b-value DWI is shown comparable to contrast-enhanced MRI and superior to T2WI in identifying mural inflammation in patients with active Takayasu arteritis. • Low b-value DWI is a fast and unenhanced MRI technique which may potentially replace contrast-enhanced MRI in identifying disease activity of Takayasu arteritis.