The findings of proton MR spectroscopy in chronic focal pancreatitis and pancreatic cancer

Abstract

Background/Aims: The differential diagnosis between chronic focal pencrentitis (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, hut chronic pancreatitls may cause a focal pancreatic mass, usually in the head. This study aimed to know the differences of in rive proton MR spectroscopic features between CFP and PC, and to evaluate the possibility to discriminate CFP from PC by analysis of in rive 'H-MR spectra. Methods: We evaluated the in vivo ~H-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 histopathotogy after surgical resection. Proton MR spectroscopy (~H-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) cm 3, and one NEX. The ratio of peak area of all peaks at 1.6-4.1ppm to lipid (O.9-1.6ppm) [P(1.64.1ppm)/P(O.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 rive 1H-MR spectra. Results:/n rive 1H-MR spectra of CFP showed significantly diminished amount of lipids as compared with that of PC. The ratio of P(1.64.1ppm)/P(O.9-1.Sppm) in CFP was much higher than that in PC with a statistical significance (p<O.05) due to decreased peak area of lipids. Mean _+ standard deviation of P(1.6-4.1ppm)/ P(O.9-1.6ppm) in CFP and PC group were 2.78 +_ 1.67 and 0.35 _+ 0.09, respectively. W'~ a cut-off value of 0.6 for discriminating CFP from PC, both the s e n s ~ and specificity were 100%. Conclusion: CFP and PC can be distinguished from each other by analysis of in rive ~H-MR spectra, and in vivo ~H-MRS can he a useful method for making differential diagnosis between CFP and PC.