Intussusception in Adults: The Role of MDCT in the Identification of the Site and Cause of Obstruction

Abstract

Unlike pediatric intussusception, intestinal intussusception is infrequent in adults and it is often secondary to a pathological condition. The growing use of Multi-Detector Computed Tomography (MDCT) in abdominal imaging has increased the number of radiological diagnoses of intussusception, even in transient and nonobstructing cases. MDCT is well suited to delineate the presence of the disease and provides valuable information about several features, such as the site of intussusception, the intestinal segments involved, and the extent of the intussuscepted bowel. Moreover, MDCT can demonstrate the complications of intussusceptions, represented by bowel wall ischemia and perforation, which are mandatory to promptly refer for surgery. However, not all intussusceptions need an operative treatment. In this paper, we review the current role of MDCT in the diagnosis and management of intussusception in adults, focusing on features, as the presence of a leading point, that may guide an accurate selection of patients for surgery.

Figure 1

Enteroenteric intussusception. Axial CT images (a, b) demonstrate a round mass with “target” pattern and central hypodense area of mesenteric fat in which vessels are seen as linear enhanced structures (arrow). Oblique CT reformatted images (c, d) oriented parallel to the longitudinal axis of the intussusception depict intussusception as a large “sausage-shaped” mass, showing length of involvement. Gas-fluid levels in the dilated proximal loops are signs of small bowel obstruction.

Figure 2

Enterocolonic (ileocaecocolonic) intussusception. Intussusception may present as a target (a), reniform bilobed (b, c), and a sausage-shaped (d) mass depending on the different axial CT scans or reformatted planes. Mesenteric vessels appear as enhanced linear structures between hypodense mesenteric fats (arrow). Dilated proximal bowel loops are opacified with oral contrast.

Figure 3

Enterocolonic (ileocaecocolonic) intussusception caused by intestinal lymphoma, with proximal bowel obstruction. Plain abdominal radiography (a) shows gas-fluid levels within distended small bowel loops. Intussusception is well depicted on axial CT scans (b, c) and coronal reformatting (d).

Figure 4

Enterocolic (ileocaecocolonic) intussusception due to a caecal carcinoma. CT images on axial scans (a, b) and oblique reformatting (c, d) show lymph nodes and vascular engorgement in the intussuscepted mesentery and fluid distention of the intussuscipiens. Extraparietal air indicates local perforation (arrow).

Figure 5

Colocolonic (sigmoid) intussusception caused by a lipoma. Ultrasound scan (a) shows a pelvic layered ovoid mass. CT images on axial (b) and oblique reformatting (c, d) demonstrate an intraluminal lesion with fat attenuation (arrow) that serves as the intussusception lead point.

Figure 6

Enteroenteric (ileoileal) transient intussusception in a traumatized patient. Axial CT images oriented perpendicular to the longitudinal plane of the intussusception demonstrate the typical multilayered appearance of small bowel intussusception. Heterogeneous “target” mass with the intussuscipiens, intussusceptum, and vessels within the invaginated mesenteric fat. No signs of significative obstruction, only mild stasis in the small bowel.

Figure 7

Enteroenteric (ileoileal) intussusception caused by lymphoma. Axial CT images show the typical appearance of small bowel intussusception (a, b, and c). Marked circumferential thickening of the wall of a distal ileum loop (d) is due to lymphoma, which is responsible for intussusception.

Figure 8

Enteroenteric (ileoileal) intussusception. Target-like mass on axial CT images. Transient intussusception with no signs of intestinal obstruction or intestinal ischemia.

Figure 9

Enteroenteric (ileoileal) intussusception secondary to colic obstruction caused by a sigmoid cancer. Intussusception appears as a small target mass (a, b) in a condition of intestinal obstruction with massive small and large bowel dilatation, due to stenosing sigmoid cancer (d). Coronal (e) and sagittal (f) reformatting better depict the site and the extent of intussusception.

Figure 10

Enteroenteric (ileoileal) intussusception. Bowel wall of intussusception is thickened and enhanced. Signs of small bowel obstruction are seen on axial scans (a, b) and coronal (c) and sagittal (d) reformatting.

Figure 11

Colocolonic intussusception caused by a sigmoid lipoma. The intussusception is well depicted on axial CT scan (a). Both axial scan (b) and coronal reformatting (c) show the hypodense polypoid mass that acts as the lead point.

Figure 12

Colocolonic (sigmoid-rectal) intussusception (a) caused by sigmoid adenocarcinoma. The enhanced neoplastic mass, which acts as the lead point, is located in the rectum (arrow), at the tip of intussusceptum (b, c, d, and e).

Figure 13

Enterocolic (ileocaecocolonic) intussusception caused by a caecal carcinoma. Ultrasound scan (a) shows a heterogeneous target-like mass located in right flank. CT images on axial scans (b, c) and coronal and oblique reformatting (d, e) demonstrate lead point intussusception with invaginated mesenteric fat, vessels, and lymph nodes.

Figure 14

Enterocolonic (ileocaecocolonic) intussusception caused by a polyp. Axial CT images (a, b) demonstrate a soft-tissue density round mass with thin eccentric hypodensity (arrow). Oblique CT reformatting (c, d) clearly shows the enhancement of the lead mass, which facilitates its identification.