Gallbladder perforation: correlation of cholescintigraphic and sonographic findings with the Niemeier classification. We retrospectively analyzed the cholescintigrams and sonograms of 36 consecutive patients with gallbladder perforation to (a) determine the sensitivity of each for the preoperative detection of gallbladder perforation and (b) correlate the findings with the modified Niemeier classification. Cholescintigraphic criteria of perforation (free spill, pericholecystic hepatic activity, and scintigraphic gallstone ileus sign) were detected in 14 of 28 (50%) cases, while sonographic criteria of perforation (pericholecystic fluid or pneumobilia with gallstones) were present in 18% (4 of 22) of patients (p less than 0.05). Cholescintigraphic patterns of perforation associated with the Niemeier classification were: Type I (acute free perforation), 3 of 7 scans demonstrated free spill; Type II (subacute pericholecystic abscess), 9 of 19 scans showed pericholecystic activity; and Type III (chronic cholecystoenteric fistula), 1 of 3 scans showed a scintigraphic gallstone ileus. Thus, although cholescintigraphy appears superior to sonography, both modalities are relatively insensitive for the detection of gallbladder perforation. 