MDCT Findings in Gastrointestinal Perforations and the Predictive Value according to the Site of Perforation

Abstract

Background: Gastrointestinal perforations are a frequent cause of acute abdominal symptomatology for patients in the emergency department. The aim of this study was to investigate the findings of multidetector-row computed tomography of gastrointestinal perforations and analyze the impact of any imaging signs on the presurgical identification of the perforation site. Methods: We retrospectively reviewed emergency MDCT findings of 93 patients submitted to surgery for gastrointestinal perforation at two different institutions. Two radiologists separately reviewed the emergency MDCT examinations performed on each patient, before and after knowing the surgical diagnosis of the perforation site. A list of findings was considered. Positive predictive values were estimated for each finding with respect to each perforation site, and correspondence analysis (CA) was used to investigate the relationship between the findings and each of the perforation types. Results: We did not find inframesocolic free air in sigmoid colorectal perforations, and in rare cases, only supramesocolic free fluid in gastroduodenal perforations was found. A high PPV of perivisceral fat stranding due to colonic perforation and general distension of upstream loops and collapse of downstream loops were evident in most patients. Conclusions: Our data could offer additional information on the perforation site in the case of doubtful findings to support surgeons, especially in planning a laparoscopic approach.

Keywords: MDCT; acute abdomen; emergency; intestinal perforations; pneumoperitoneum; surgery.

Figure 1

Scree plot showing the dimensions extracted from the CA and their explained variance.

Figure 2

Biplot of spatial relationships across dimensions for each perforation site and finding.

Figure 3

Cluster analysis performed on the results.

Figure 4

An 82-year-old male with perforation of the first portion of the duodenum caused by a peptic ulcer. The CT images show subdiaphragmatic free peritoneal air (white arrows in (A)) with “falciform ligament sign” (long black arrow in (A)). Note the periportal free air sign (short black arrow in (A)). In this case, we also found a focal wall defect (arrow in (B)).

Figure 5

A 61-year-old male with perforation of the posterior wall of the stomach. The precontrast CT scan shows retroperitoneal free air (arrow in (A,B)) only, with no evidence of gastric wall breach. Note the diffuse parietal pneumatosis of the gastric wall.

Figure 6

A 75-year-old female with perforation of the anterior gastric wall. In this case, CT shows focal abnormal wall thickening at the site of perforation (arrow in (A)), with the presence of a peripheral small amount of free air. There is also free fluid in the pelvis (B).

Figure 7

A 45-year-old female with perforation of the anterior gastric wall. In this case, we found a defect of continuity (arrow in (A)) at the site of perforation and subdiaphragmatic free fluid (arrowhead in (B)) but a very small amount of free air (arrow in (C)).

Figure 8

A 54-year-old male with ileal perforation. Only inframesocolic air bubbles (arrow in (A,B)) were found, with no free peritoneal fluid. Note the hyperdense foreign body in the small bowel loop (arrowhead in (A), a chicken bone).

Figure 9

A 35-year-old female with aspergillosis of the ileum and surgical diagnosis of the ischemic ulcerative circumferential lesion at the proximal ileum involving all layers of the ileal wall with concealed perforation. The axial (A), coronal (B) and sagittal (C) images show focal posterior bowel wall disruption with increased enhancement and thickness of the involved bowel segment (long arrows). Surrounding fat stranding and a small amount of fluid are noted (short arrows).

Figure 10

A 67-year-old female with a descending colon perforation. CT images show both supra- and inframesocolic free intraperitoneal air (arrows in (A,B)). A focal wall defect was identified (arrow in (C,D)). Note the air bubbles near the perforation site (short arrow in (D)) and the reactive segmental wall thickening with the submucosal edema of the ileal loop close to the colonic wall discontinuity.

Figure 10

A 67-year-old female with a descending colon perforation. CT images show both supra- and inframesocolic free intraperitoneal air (arrows in (A,B)). A focal wall defect was identified (arrow in (C,D)). Note the air bubbles near the perforation site (short arrow in (D)) and the reactive segmental wall thickening with the submucosal edema of the ileal loop close to the colonic wall discontinuity.

Figure 11

A 69-year-old female with a history of santol seed ingestion. Surgical diagnosis was full thickness of necrosis of the upper rectum with retained santol seed in the submucosal layer. CT shows retroperitoneal free air in the inframesocolic compartment (arrow in (A)), round hyperdense opacification in the middle of the fecal-like content adjacent to the involved upper rectum (arrow in (B)) and free air close to the involved upper rectum (C). Note the focal bowel wall disruption with abnormal thickness and enhancement of the involved upper rectum (D,E).

Figure 11

A 69-year-old female with a history of santol seed ingestion. Surgical diagnosis was full thickness of necrosis of the upper rectum with retained santol seed in the submucosal layer. CT shows retroperitoneal free air in the inframesocolic compartment (arrow in (A)), round hyperdense opacification in the middle of the fecal-like content adjacent to the involved upper rectum (arrow in (B)) and free air close to the involved upper rectum (C). Note the focal bowel wall disruption with abnormal thickness and enhancement of the involved upper rectum (D,E).

Figure 12

A 77-year-old male with sigmoid colon perforation. Note perivisceral fat stranding and edema surrounding the descending colon (arrows in (A)). The perforated segment showed wall edematous thickening and enhancement (arrow in (B)). There was no free peritoneal air evidence but perihepatic free fluid (arrow in (C)).