Objective: To compare the value of CT using different equipment and scanning methods in preoperative localization of insulinoma and to investigate the possible causes that might influence the detection ratio on CT.
Methods: A total of 47 patients with insulinomas confirmed by operation and pathologic examination from 1990 were collected, and the related clinical information and imaging data of CT were retrospectively analyzed.
Results: The diagnostic accuracy for conventional CT with conventional enhancement scanning, spiral CT with pancreatic phase scanning, and multislice spiral CT with dual phasic enhancement scanning were 35.3%, 57.1%, and 81.3%, respectively, and the overall diagnostic accuracy of CT was 57.4%. The diagnostic accuracy of multislice spiral CT was greater than that of conventional CT (P<0.01). For the 2 phases of dual phasic imaging, arterial phase and portal phase had a detective rate of 75.0%and 62.5%, respectively. None of the main clinical information was related to the detection ratio on CT. The detection rate of lesions with diameter of > or =1.5 cm was significantly higher than that of <1.5 cm (76.2%vs. 42.3%). Typical appearance of the lesions on CT was isoattenuation on plain scanning, and enhanced considerably after contrast enhancement.
Conclusion: The size of lesion is the major factor that influences the detection of insulinoma on CT. Multislice spiral CT with dual phasic enhancement scanning has a relatively high detection rate and is recommended for preoperative localization of insulinoma.