Spontaneous free perforation of the ileum in Crohn disease: CT demonstration

Multidetector CT findings suggesting a perforation site in the gastrointestinal tract: analysis in surgically confirmed 155 patients

PURPOSE

The aim of this study was to investigate how accurately we could diagnose the level of gastrointestinal (GI) tract perforation using multidetector computed tomography (MDCT).

MATERIALS AND METHODS

We reviewed 155 patients with surgically confirmed GI tract perforation. MDCT scans were obtained with eight-detector CT; 5 mm thick axial images and 2.5 mm thick coronal multiplanar reconstruction (MPR) images were generated for all patients. Contrast enhancement was performed in 44 of the 155 patients. Two board-certified radiologists reviewed the images for direct findings (free air, ruptured GI tract wall) and indirect findings (inflammatory changes, fluid collection, focal thickening of the GI tract wall) and attempted to identify the perforation site in each patient.

RESULTS

Free air was seen in more than 95% of the patients with perforation at sites other than the appendix; free air was seen in 44% of patients with appendicitis. On contrast-enhanced CT performed in 44 patients, rupture of the wall of the GI tract was directly visualized in 14 (32%) on axial images only and in 23 (52%) on axial or MPR images, respectively. The perforation site was correctly diagnosed in 90% of the patients when the radiologists referred to both direct and indirect findings.

CONCLUSION

MDCT was valuable for identifying the presence and level of GI tract perforation.

Plain radiography for diagnosis of gastrointestinal perforation in immune-compromised children--is it enough?

Gastrointestinal perforation is a surgical emergency in the pediatric patient and any delay in diagnosis might be hazardous. In immunocompromised children, the clinical signs of perforation may be blunted. We describe a child with acute lymphoblastic leukemia (ALL) and a perforated appendix and ileum in whom computerized tomography (CT) revealed extraluminal air that was not initially identified on plain abdominal film. Our case demonstrates the importance of early abdominal CT and ultrasound examination in detecting these potentially lethal complications.

Current CT/MRI examination of the lower intestinal tract

For evaluating primary colonic and rectal malignancies, CT and MRI are often complementary imaging methods which are useful in assessing patients suspected of having extensive disease and in deciding whether a patient will benefit from preoperative radiation. CT is also helpful in designing radiation ports and in detecting complications related to the neoplasm such as perforation with abscess formation. MRI offers excellent tissue resolution which aids in distinguishing between localized colorectal disease and disease which invades muscle. Also, MRI can add information with coronal views for determining whether a sphincter-saving procedure can be performed, and may be of benefit for assessing the subtle extent of tumour into muscle and bone. However, CT and MRI lack the ability to assess depth of neoplastic involvement within bowel wall. This limitation is the major factor which, combined with the inability to diagnose metastatic tumour foci in normal-sized nodes and microinvasion of perirectal fat, prevents optimal tumour staging. Because of the low accuracy for assessing early cancer stages, neither CT nor MRI are recommended for routine use in preoperative staging. CT and MRI have a premier role in the assessment of recurrent colorectal neoplasm, with CT providing a slightly better overall evaluation due to volume imaging, easy image reconstructions in different planes, and availability of excellent oral and intravenous contrast agents. Cross-sectional imaging is the only method to evaluate fully patients with total AP resection, particularly male patients. Neither CT nor MRI can determine with certainty that a soft tissue density in the surgical bed following total AP resection represents recurrent tumour unless a clear mass is present which has increased in size over time. However, both methods surpass colonoscopy for detecting early mass-like tumour recurrence at the anastomotic site due to its extrinsic component. Cross-sectional imaging plays a prominent role in assessing inflammatory disease of the colon. Clinical history, laboratory data and extent of involvement are used together with results from radiographic examinations to reach a specific diagnosis. CT is preferred over MRI in the assessment of extent of inflammatory disease in and beyond the bowel wall. An additional benefit of CT over MRI is the fact that patients with abscesses or large fluid collection can undergo drainage while still in the CT scanner. CT and MRI can aid in the distinction between ulcerative colitis with minimal wall-thickening and Crohn's disease with marked wall-thickening combined with skip lesions and fistula and/or abscess formation.(ABSTRACT TRUNCATED AT 400 WORDS)