DUAL-PHASE HELICAL CT OF NONFUNCTIONING ISLET-CELL TUMORS (VOL 22, PG59, 1998)

Purpose: The aim of this study was to evaluate the utility of dual-pha se imaging in the assessment of nonfunctioning islet cell tumors (NFIT s). Method: Six patients with histologically and biochemically proven NFIT were evaluated by arterial and portal venous dual-phase helical C T. Scan delay was 20s for the arterial phase and 70s for the portal ph ase. Each phase was assessed by consensus reading and specifically eva luated for tumor conspicuity, hepatic metastases, vascular encasement by tumor, and presence of lymphadenopathy. Results: Overall, tumor con spicuity was greater in the arterial phase (5/6) than in the portal ve nous phase (1/6) with a mean tumor/normal pancreas attenuation differe nce of 31.8 HU in the arterial phase compared with 19.2 HU in the port al venous phase. The arterial phase detected a total of 17 liver metas tases compared with 9 seen in the portal phase. Lymph node enlargement was noted in three patients, which, although visible in both phases, was more easily discernible in the arterial phase. Venous encasement b y tumor was better evaluated on the delayed portal venous phase than t he arterial phase. Conclusion: Dual-phase helical CT scanning leads to improvement in the detection and staging of NFITs.