Evaluation of fibrotic liver disease with whole-liver T1ρ MR imaging: a feasibility study at 1.5 T.

PURPOSE: To test at 1.5 T whether T1ρ magnetic resonance (MR) imaging of fibrotic liver disease is feasible, to investigate whether liver T1ρ imaging allows assessment of the severity of liver cirrhosis, and to assess the normal liver T1ρ range in healthy patients. MATERIALS AND METHODS: This prospective study was approved by the institutional ethics committee. Written informed consent was obtained. Healthy volunteers (n = 25) and patients (n = 34) with cirrhosis underwent whole-liver T1ρ MR imaging at 1.5 T. Mean T1ρ values were calculated from liver regions of interest. Mean T1ρ values were correlated to clinical data and histopathologic analysis by analysis of variance. Receiver operating characteristic curves were calculated to determine the accuracy of mean T1ρ values for the assessment of Child-Pugh class. RESULTS: Mean T1ρ values of volunteers (mean, 40.9 msec ± 2.9 [standard deviation]; range, 33.9-46.3 msec) were significantly lower than those of patients who were Child-Pugh class A (P < .004), B (P < .001), or C (P < .001), and significant differences were found between each Child-Pugh stage (A vs B, P < .002; B vs C, P < .009; A vs C, P < .001). Liver cirrhosis was confirmed via histologic analysis in all patients with liver biopsy. Mean T1ρ values did not correlate with necroinflammatory activity (r = 0.31; P = .23), degree of steatosis (r = -0.016; P = .68), or presence of iron load (r = 0.22; P = .43). Mean T1ρ values performed well by assessing the Child-Pugh stage, with receiver operating characteristic areas of 0.95-0.98. Intraclass correlation coefficient values ranged between 0.890 and 0.987, which indicated excellent imaging and reimaging reproducibility and interobserver and intraobserver variability. CONCLUSION: Whole-liver T1ρ MR imaging at 1.5 T to detect and assess human liver cirrhosis is feasible. Further investigation and optimization of this technique are warranted to cover the entire spectrum of fibrotic liver disease.