Value of MR diffusion weighted imaging in assessing the viability of hepatic alveolar echinococcosis

Abstract

Objective To evaluate DWI in the assessment of viability of hepatic alveolar echinococcosis (HAE) by comparing DWI with PET-CT results. Methods 18-fluorodeoxy glucose(18F-FDG) PET-CT and DWI(b values=0, 800 s/mm2) were retrospectively analyzed in 8 patients with clinically verified HAE. The metabolic activity of HAE lesions in both techniques were determined by two independent radiologists respectively. Kappa test was assessed between the results of two observers. Results Sixteen lesions (composed of 14 HAE and 2 cystic echinococcosis, CE) were detected.(1)Eight lesions (≥2 cm) showed perilesional hyper-signal intensity on DWI, mainly around the lesion bounding by normal liver parenchyma. One patient (≥2 cm) had oral drug therapy for three years, and the lesion showed discontinuous perilesional hyper-signal intensity on DWI after the therapy. Five lesions (<2 cm) were depicted as nodular high signal on DWI.(2)Eight lesions (≥2 cm) showed perilesional increased FDG uptake on PET-CT, while 5 lesions (<2 cm) displayed ashot pot. One patient (leison≥2 cm) who had oral drug therapy for three years showed hepatic defect without any FDG uptake in post-treatment PET-CT. Two CE lesions showed negative results on both DWI and PET-CT. The Kappa value of 0.880 indicated a good coincidence between DWI and PET-CT in depicting the metabolic activity of HAE (P=0.006). Conclusions This preliminary study showed the value of DWI in assessing HAE viability. DWI should be routinely used as one of the techniques in the evaluation of HAE. Key words: Echinococcosis, hepatic; Magnetic resonance imaging; Tomography, X-ray computed