The Value of Urgent Barium Enema and Computed Tomography in Acute Malignant Colonic Obstruction: Is Urgent Barium Enema Still Necessary?

The aim of this study was to evaluate the necessity of urgent barium enema in suspected cases of acute malignant colonic obstruction. We reviewed the medical records and images for 20 patients with suspected acute colonic obstruction. Nine patients were excluded. Computed tomography (CT) and urgent barium enema images for the remaining 11 cases were reviewed and the results were compared with the surgical findings. The rate of correct diagnosis of obstruction level was compared between CT and barium enema. The diameters of different colonic segments were analyzed on CT, and several different parameters were compared with the obstruction severity on barium enema. Both CT and barium enema correctly predicted the obstruction level in 100% of the cases. The extent of colonic dilatation was not significantly different between total obstruction and partial obstruction (P > 0.05). The sensitivity and specificity of the continuity sign on CT to predict partial obstruction were 33.33% and 100%, respectively. The possibility of total obstruction for an obstructive lesion distal to the splenic flexure was not statistically different from that for an obstructive lesion proximal to the splenic flexure (P > 0.05). Urgent barium enema is not necessary in suspected cases of acute malignant colonic obstruction, predominantly due to the advancement in both CT and surgical management of such cases. Correspondence Author to: Fei-Shih Yang Department of Radiology, Mackay Memorial Hospital, Taipei, Taiwan No. 92, Sec. 2, Chung-Shan N. Road, Taipei 104, Taiwan J Radiol Sci 2012; 37: 105-110 Barium enema and CT in acute colonic obstruction 106 J Radiol Sci September 2012 Vol.37 No.3 always available in hospitals; in such cases, such as in our hospital, the decision between emergent and elective surgery will be based on whether the colon is totally obstructed [6]. The hypothesis of this concept is that total obstruction may result in more severe dilatation of the colon and consequently a higher colonic perforation rate. Therefore, early surgical intervention for total obstruction is indicated. If the severity of dilatation is not different between total and partial obstruction, the need for urgent contrast enema will be lessened. This study aims to evaluate the necessity of urgent barium enema in suspected cases of acute malignant colonic obstruction. MATeRiAl And MeThodS Patients In this retrospective study, we collected and reviewed the medical records and imaging studies of 20 patients who presented to the emergency department of our hospital between October 2007 and November 2011 and were clinically suspected of having acute colonic obstruction. All 20 patients underwent both urgent barium enema and abdominal CT. We excluded 9 patients: 2 patients underwent barium enema before CT; another 2 patients showed obvious ileocolonic intussusception on CT; and the remaining 5 patients were eventually diagnosed with ischemic bowel disease, paralytic ileus, adhesive ileus, diverticulitis, and unknown disease, respectively. The patient with unknown disease was highly suspected of having descending colon cancer on CT and barium enema, but the patient died before she was able to undergo surgical resection of the problematic colon lesion. The 11 cases in this study included 3 women and 8 men (age range: 47–86 years; mean: 64.4 years). Of the 11 cases, 10 patients were eventually diagnosed with colon cancer (ascending colon: 2; transverse colon: 3; descending colon: 2; sigmoid colon: 2; and rectum: 1), and the remaining patient had sigmoid colonic metastasis from endometrial cancer. imaging techniques CT: All CT scans were performed without (slice thickness: 5 mm) and with (slice thickness: 2 mm) intravenous contrast injection using one of two 64-channel multidetector CT scanners. Coronal reconstruction (slice thickness: 3 mm) was performed from the enhanced series. For each patient, 80 mL non-ionic or ionic iodinated contrast media was administered intravenously. Neither oral contrast nor rectal contrast was administered. Barium enema: All barium enema studies were performed by radiologists. The procedure was terminated when the colon was fully distended or when an obstructive lesion was identified. If there was an obstructive lesion, barium was continuously infused until the distal segment of the colon was fully distended for at least 10 seconds to evaluate whether barium could pass through the obstruction. No intravenous medication was administered for this study. Definitions The obstruction level, the diameters of the segments proximal and distal to the obstruction, and the continuity of the lumen through the obstructive lesion were recorded based on CT images. The obstruction level was divided into 5 groups including ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. The diameters of the proximal (Pro-diameter) and distal (Dis-diameter) segments were defined as the maximum diameters of the adjacent segments proximal and distal to the obstructive lesion, respectively. The ratio (P-D ratio) between Prodiameter and Dis-diameter was then calculated. In addition, whenever the intraluminal air or fluid could be continuously traced through the obstructive lesion, the continuity was considered positive (Fig. 1). Based on barium enema, the obstruction level was also divided into the same 5 groups as those based on CT images. When contrast could pass through the obstructive lesion during barium enema, partial obstruction was considered (Fig. 1). In other cases, total obstruction was favored (Fig. 2). The definite obstruction level of each case was determined according to the intraoperative findings, and the final diagnosis was based on the pathology report. Statistical analysis The sensitivities and specificities of CT and barium enema in localizing the definite obstruction level were compared. The Pro-diameter, Dis-diameter, and P-D ratio were separated into the partial obstruction group and the total obstruction group to elucidate any significant differences between the 2 groups. The value of the continuity sign to predict partial or total obstruction was also analyzed. The possibility of total obstruction was compared between 2 distinct obstruction levels (proximal or distal to the splenic flexure). These calculations were performed using the software SPSS for Windows (Version 17), and a P value of less than 0.05 was considered statistically significant (Student’s t-test).