AJR:185, November 2005 1159 AJR 2005; 185:1159–1165 0361–803X/05/1855–1159 © American Roentgen Ray Society Lassandro et al. CT of Gallstone Ileus Gastrointestinal Imaging • Clinical Observations Role of Helical CT in Diagnosis of Gallstone Ileus and Related Conditions Francesco Lassandro 1 Stefania Romano 1 Alfonso Ragozzino 1 Giovanni Rossi 2 Tullio Valente 2 Ilaria Ferrara 3 Lugia Romano 1 Roberto Grassi 3 Lassandro F, Romano S, Ragozzino A, et al. DOI:10.2214/AJR.04.1371 Received August 31, 2004; accepted after revision November 23, 2004. 1 Department of Diagnostic Imaging, A. Cardarelli Hospital, Viale Cardarelli 9, Naples 80131, Italy. Address correspondence to S. Romano (stefromano@libero.it). 2 Department of Radiology, A. Monaldi Hospital, Naples, Italy. 3 Institute of Radiology, Second University of Naples, Naples, Italy. OBJECTIVE. Small-bowel obstruction from gallstone impaction is a pathological entity frequently observed in elderly patients with a history of cholelithiasis or cholecystitis. Diagnos- tic imaging plays a great role in the management of patients with suspected gallstone ileus and overall in the correct predictive diagnosis: in the last years, some experiences in radiologic di- agnosis of this entity by sonography, abdominal plain film and CT, and occasionally MRI have been reported. Some questions related to gallstone ileus are to be considered: one of them is the possibility of recurrence, which increases the operatory risk in these patients. Recurrence may be due either to the presence of overlooked stones that were already in the bowel at the time of surgery but not identified and not removed or to the migration of other stones in patients not pre- viously cholcystectomized. In cases of acute abdomen, establishing an effective conservative therapy may be a critical point. The aim of this retrospective study was to evaluate the capabil- ities of helical single-detector and MDCT scanners to allow a correct diagnosis of this disease. CONCLUSION. Helical single-detector and MDCT may improve the diagnosis of gall- stone ileus, providing important information regarding the exact number, size, and location of ectopic stones and the site of intestinal obstruction or direct visualization of a biliary–enteric fistula, to help clinicians in the therapeutic management of patients. mall-bowel obstruction is a daily occurrence in all emergency de- partments. Radiologists are fre- quently asked about the cause of a mechanical occlusion, and CT has become the best diagnostic technique for imaging emer- gency patients [1]. The main cause of intestinal obstruction is adhesions; however, some un- common entities may represent an interesting theme to investigate. One of them is the gall- stone ileus, a mechanical intestinal obstruction caused by impaction of gallstones in the lumen of the bowel, which was first described by Bar- tholin in 1654 [2]. The main problem related to this disorder is its frequency in elderly persons, which seems to increase to 25% of all nonstran- gulated intestinal obstructions [3]. Patients of- ten present with a history of cholelithiasis or cholecystitis; women are more commonly af- fected than men [3]. Gallstone ileus has a high mortality rate, ranging from 8% to 30% [3–5]; other concomitant diseases may increase the operative risk in patients older than 65 years. Diagnostic imaging plays an important role in the management of patients with suspected gallstone ileus; some authors have recently re- ported their experience in the radiologic diag- nosis of this entity on sonography, abdominal radiography, CT, and occasionally MRI [6–9]. Some questions related to gallstone ileus must be considered. One is the possibility of recurrence, which increases the surgical risk in these patients. Recurrence may be due either to the presence of overlooked stones that were al- ready in the bowel at the time of surgery but not identified and removed, or to the migration of other stones in patients who have not previ- ously undergone cholecystectomy [3, 10–12]. In patients with an acute abdomen, the es- tablishment of an effective conservative ther- apy may be critical. In these patients with no findings of mechanical ileus, CT may in- crease the detection of stones not yet im- pacted [13]. Finally, the surgical treatment of these patients is a challenge, especially be- cause of the possibility of a laparoscopic en- terolithotomy or a one-stage procedure of fis- tula repair and cholecystectomy, to reduce the risk of complications and to decrease the high postoperative mortality rate [14, 15]. The aim of this retrospective study was to evaluate the possibilities of helical CT and es- pecially of the new generation of MDCT scan- ners to allow a correct diagnosis of gallstone S