PANCREATIC MASSES WITH INCONCLUSIVE FINDINGS ON SPIRAL CT - IS THERE A ROLE FOR MRI

This prospective study evaluates the ability of MRI using T1-weighted fat-suppressed spin-echo (T1FS) and dynamic gadolinium chelate (Gd) en hanced spoiled-gradient echo (SGE) to detect the presence of pancreati c tumor in patients in whom spiral CT findings are inconclusive, Sixte en consecutive patients who underwent spiral CT and had findings that were considered inconclusive for pancreatic tumor underwent MR within 2 weeks of CT. Spiral CT and MR images were interpreted in a prospecti ve fashion by separate individual investigators blinded to the results of the other imaging modality. CT was performed on a spiral CT scanne r, MRI was performed on a 1.5-T MR machine. Imaging sequences included T1FS pre-Gd and post-Gd and SGE pre-Gd and immediately post-Gd, Data were analyzed using receiver operating characteristic (ROC) analysis. Confirmation was obtained by pancreatic biopsy (n = 4), surgical resec tion (n = 1), and clinical imaging (n = 4) or clinical follow-up (n = 7), MRI was superior to spiral CT (P = .027) in this selected patient group at detecting or excluding pancreatic tumor by ROC analysis, with areas under the curve of .982 and .764, respectively, which was signi ficant (P = .041). The greatest advantage of MRI was in patients in wh om spiral CT demonstrated enlargement of the pancreatic head without c lear definition of tumor, which was significant (P = .033), In 10 pati ents with this CT appearance, MRI demonstrated a high confidence for p resence of tumor in four and a high confidence of absence in six, Asso ciation of imaging findings with patient diagnosis was significant for MRI (P = .001) but not significant for CT (P = .148) The results of o ur study suggest that MRI may add significant diagnostic information i n patients in whom spiral CT is inconclusive for the presence of pancr eatic tumor, The greatest advantage of MRI was in the evaluation of pa tients in whom spiral CT findings revealed an indeterminate enlarged p ancreatic head.