SMALL POLYPOID LESIONS OF THE GALLBLADDER - DIFFERENTIAL-DIAGNOSIS AND SURGICAL INDICATIONS BY HELICAL COMPUTED-TOMOGRAPHY

Objectives: To demonstrate the helical computed tomographic (CT) featu res of small polypoid lesions of the gallbladder and to establish a cl inical strategy based on CT findings for the treatment of such lesions . Design: Validation cohort study. Setting: Tertiary care public hospi tal. Patients: Thirty-one patients with polypoid lesions of the gallbl adder (less than or equal to 3 cm) underwent CT followed by resection. Main Outcome Measure: The detectability of the lesions on both unenha nced and enhanced CT and the configuration of the lesions on enhanced CT were prospectively evaluated in comparison with the histopathologic al findings. Results: Unenhanced CT detected 14 (45%) of the 31 lesion s, whereas enhanced CT detected all of the lesions. The detection rate s of the neoplastic lesions (adenoma, adenocarcinoma, and metastatic t umor) and cholesterol polyps were 81% (13/16) and 7% (1/15), respectiv ely (P<.001). Among the 20 lesions demonstrated as pedunculated, 6 (30 %) were neoplastic, whereas 10 (91%) of the 11 lesions demonstrated as sessile were neoplastic (P<.001). When a lesion was demonstrated on u nenhanced CT or its shape was sessile on enhanced CT, the case was dia gnosed as a neoplastic lesion. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of t he CT diagnosis of the neoplastic lesions were 88% (14/16), 87% (13/15 ), 88% (14/16), 87% (13/15), and 87% (27/31), respectively. Conclusion : Computed tomography can differentiate neoplastic and nonneoplastic s mall polypoid lesions of the gallbladder and reliably identify the pre sence of neoplastic lesions that should be resected.