The relationship of in vivo31P MR spectroscopy to histology in chronic hepatitis C

Liver biopsy remains the gold standard for characterizing diffuse liver disease and is associated with significant morbidity and, rarely, mortality. Our aim was to investigate whether a noninvasive technique, in vivo phosphorus 31 ( 31 P)–magnetic resonance spectroscopy (MRS), could be used to assess the severity of hepatitis C virus (HCV)–related liver disease. Fifteen healthy controls and 48 patients with biopsy–proven HCV–related liver disease were studied prospectively. Based on their histologic fibrosis (F) and necroinflammatory (NI) scores, patients were divided into mild hepatitis (F ≤ 2/6, NI ≤ 3/18), moderate/severe hepatitis (3 ≤ F < 6 or NI ≥ 4/18), and cirrhosis (F = 6/6). Hepatic 31 P MR spectra were obtained using a 1.5–T spectroscopy system. Quantitation of the 31 P signals was performed in the time domain using the Advanced MAgnetic RESonance algorithm. There was a monotonic increase in the mean ± 1 standard error phosphomonoester (PME) to phosphodiester (PDE) ratios for the control, mild disease, moderate disease, and cirrhosis groups: 0.15 ± 0.01, 0.18 ± 0.02, 0.25 ± 0.02, 0.38 ± 0.04, respectively (ANOVA, P < .001). An 80% sensitivity and specificity was achieved when using a PME/PDE ratio less than or equal to 0.2 to denote mild hepatitis and a corresponding ratio greater than or equal to 0.3 to denote cirrhosis. No other significant spectral changes were observed. In conclusion, 31 P MRS can separate mild from moderate disease and these 2 groups from cirrhosis. The ability to differentiate these populations of patients has therapeutic implications and 31 P MRS, in some situations, would not only complement a liver biopsy but could replace it and be of particular value in assessing disease progression. (Hepatology 2003;37:788–794.)