The Findings of Proton MR Spectroscopy in Chronic Focal Pancreatitis and Pancreatic Cancer

초록

Background/Aims: The differential diagnosis between chronic focal pancreatitis (CFP) and pancreatic carcinoma (PC) is important for their difference in prognosis and method of management. Unfortunately, it is often difficult and even impossible to discriminate between them, because of their similarity of presenting clinical or radiologic features. The presence of a focal pancreatic mass is generally indicative of a neoplasm, but chronic pancreatitis may cause a focal pancreatic mass, usually in the head. This study aimed to know the differences of in vivo proton MR spectroscopic features between CFP and PC, and to evaluate the possibility to discriminate CFP from PC by analysis of in vivo 1H-MR spectra. Methods: We evaluated the in vivo 1H-MR spectra from 33 human pancreases. Our series included 15 cases of CFP and 18 cases of PC. All cases of CFP and PC were confirmed by histopathology after surgical resection. Proton MR spectroscopy (1H-MRS) was performed at 1.5T GE Signa Horizon (GE Medical System, Milwaukee, USA) system using localized proton STEAM sequence and body coil in all cases with subjects were located in supine position. No respiratory interruption was required during the spectroscopic signal acquisition. Parameters using in MRS were: TR = over 3000 ms, TE = 30 ms, number of scans = 128, voxel size = 8 (2x2x2) cm3, and one NEX. The ratio of peak area of all peaks at 1.6-4.1ppm to lipid (0.9-1.6ppm) [P(1.6-4.1ppm)/P(0.9-1.6ppm)] was calculated in CFP and PC group, and compared the results between these groups. We also evaluated the sensitivity and specificity for discriminating CFP from PC by analysis of in vivo 1H-MR spectra. Results: In vivo 1H-MR spectra of CFP showed significantly diminished amount of lipids as compared with that of PC. The ratio of P(1.6-4.1ppm)/P(0.9-1.6ppm) in CFP was much higher than that in PC with a statistical significance (p<0.05) due to decreased peak area of lipids. Mean standard deviation of P(1.6-4.1ppm)/P(0.9-1.6ppm) i