Combined magnetic resonance imaging and spectrometry for characterization of human pancreatic adenocarcinoma (Capan-1) heterotransplanted in nude mice.

Human pancreatic cancer cells (Capan-1 cell line) were heterotransplanted subcutaneously into nude mice. The resulting macroscopically visible tumours were analyzed by proton nuclear magnetic resonance spectrometry in a search for characteristic parameters. The Capan-1 xenografts were visualized by nuclear magnetic resonance imaging and were characterized by a significantly increased transverse relaxation time T2 (125 +/- 32 ms) compared with that recorded from ex vivo healthy human pancreatic tissue (60 +/- 11 ms). Three characteristic signals at 2.73, 3.23 and 3.5 ppm were observed by nuclear magnetic resonance spectrometry. They corresponded to unsaturated fatty acids, phosphatidylcholine, glycerophosphorylcholine and/or taurine respectively. These peaks were not observed in the spectra recorded from healthy human or mouse pancreas. On the basis of these parameters, small intraperitoneal Capan-1 xenografts (less than 0.5 cm diam), which were only visible at the macroscopic level after opening the abdominal cavity, were accurately localized by magnetic resonance imaging and spectrometry.