Liver Lobe Volumes and the Ratios of Liver Lobe Volumes to Spleen Volume on Magnetic Resonance Imaging for Staging Liver Fibrosis in a Minipig Model

Objective: To investigate liver lobe volumes and the ratios of liver lobe volumes to spleen volume measured with magnetic resonance imaging (MRI) for quantitatively monitoring and staging liver fibrosis. Methods: Animal study was approved by Institutional Animal Care and Use Committee. Sixteen minipigs were prospectively used to model liver fibrosis, and underwent abdominal gadolinium-enhanced MRI on 0, 5th, 9th, 16th and 21st weekend after modeling this disease staged by biopsy according to METAVIR classification system. On MRI, volume parameters including left lateral liver lobe volume (LLV), left medial liver lobe volume (LMV), right liver lobe volume (RV), caudate lobe volume (CV), and spleen volume (SV) were measured; and LLV/SV, LMV/SV, RV/SV and CV/SV were calculated. Statistical analyses were performed for staging this fibrosis. Results: LLV and CV increased with increasing stage of fibrosis (r = 0.711, 0.526, respectively; all P < 0.05). RV and LMV increased from stage 0 to 2 and decreased from 2 to 4; and RV/SV decreased from 0 to 1, increased from 1 to 2, and decreased from 3 to 4 (all P > 0.05). LLV/SV, LMV/SV and CV/SV decreased from stage 0 to 4 (r = -0.566, -0.748 and -0.620, respectively; all P < 0.05). LLV, CV, LLV/SV, LMV/SV, RV/SV, and CV/SV could distinguish stage 0-1 from 2-4 and 0-2 from 3-4 (all P < 0.05). Among these parameters, LLV and LMV/SV could best classify stage = 2 and = 3, respectively (area under receiver operating characteristic curve = 0.893 and 0.946, respectively). Conclusion: LLV and LMV/SV complement each other in staging liver fibrosis, and both parameters should be used to stage this disease.