Triphasic CT in the diagnosis of acute mesenteric ischaemia.

OBJECTIVE

To evaluate the yield of each phase in a triphasic CT protocol used to diagnose acute mesenteric ischaemia (AMI).

METHODS

Retrospective analysis of patients who underwent CT to exclude AMI was conducted. From 218 patients, 80 were randomly selected for analysis: 39 with proven AMI; 41 controls. Three readers evaluated the studies; two readers were provided with only portions of the examination to determine the yield of unenhanced CT (NECT) and CT angiography (CTA). The diagnostic accuracy of CT findings was calculated and compared between readers.

RESULTS

The sensitivity and specificity of submucosal haemorrhage were 10 % and 98 %. Interobserver variability was poor (κ = 0.17). All true-positive cases had other CT findings of AMI (n = 4). There was no difference in the assessment of bowel enhancement between readers (P < 0.05). There was no difference between readers (P < 0.05) and interobserver variability was moderate to good when diagnosing arterial abnormalities without CTA. Sample size was small and errors occurred when using only the portal venous phase for this purpose.

CONCLUSION

NECT is not required for diagnosis of AMI. Splanchnic arterial abnormalities can be diagnosed without CTA although errors occur when using only the portal venous phase for this purpose.

KEY POINTS

• Triphasic CT is the current gold standard for diagnosing acute mesenteric ischaemia. • Multiphase CT multiplies the radiation dose when compared to single phase CT. • Each phase in a multiphase CT examination should be independently validated. • Unenhanced CT is not required for diagnosis of acute mesenteric ischaemia. • CT angiography should be performed for diagnosis of acute mesenteric ischaemia.