Spleen magnetic resonance diffusion-weighted imaging for quantitative staging hepatic fibrosis in miniature pigs: An initial study

Abstract

Aim: To determine whether spleen diffusion-weighted imaging (DWI) parameters might classify liver fibrosis stage. Methods: Sixteen miniature pigs were prospectively used to model liver fibrosis, and underwent spleen DWI by using b=300, 500 and 800s/mm2 on 0, 5th, 9th, 16th and 21st weekend after the beginning of modeling. Signal intensity ratio of spleen to paraspinous muscles (S/M), spleen exponential apparent diffusion coefficient (eADC) and apparent diffusion coefficient (ADC) for each b-value were statistically analyzed. Results: With increasing stages of fibrosis, S/M for all b-values showed a downward trend; and spleen eADC and ADC for b=300s/mm2 showed downward and upward trends, respectively (all P<0.05). The area under the receiver-operator curve (AUC) of spleen DWI parameters was 0.777 or more by S/M for classifying each fibrosis stage, and 0.65 or more by eADC and 0.648 or more by ADC for classifying stage ≥3 or cirrhosis. Among the spleen DWI parameters, S/M for b=300s/mm2 was the best parameter in classifying stage 1 or more, 2 or more and 3 or more with AUC of 0.875, 0.851 and 0.843, respectively; and spleen eADC for b=300s/mm2 was best in classifying stage 4 with an AUC of 0.988. Conclusion: Spleen DWI may be used to stage liver fibrosis. © 2013 The Japan Society of Hepatology.