Comparison of diagnostic performance between 1 millisievert CT enterography and half-standard dose CT enterography for evaluating active inflammation in patients with Crohn’s disease

Abstract

Purpose

To compare the diagnostic performance of CT enterography (CTE) images obtained at 1 millisievert (mSv) and reconstructed with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) with those of half-dose CTE images for the evaluation of active inflammation in patients with Crohn’s disease.

Methods

Forty-six consecutive patients (mean age 29 years; range 15–59 years) with Crohn’s disease underwent CTE which comprised a standard-dose scan at the enteric phase (45 s), a half-dose scan with ASIR at the portal venous phase (70 s), and 1 mSv scans with FBP and ASIR at the delayed phase (90 s) under a fixed 120 kVp and variable mAs. Two blinded readers independently recorded confidence scores for active inflammation in the ileum and terminal ileum, respectively. The diagnostic performance of each image set was compared by pairwise comparison of receiver operating characteristic curves. The established image findings on standard-dose scan and ileocolonoscopy served as the reference standard.

Results

A total of 92 bowel segments were analyzed. For reader 1, the diagnostic performance was increased from 1 mSv CT with FBP and 1 mSv CT with ASIR to half-dose scan with ASIR (AUC, 0.759, 0.794, and 0.845; P = 0.1429, P = 0.0107, respectively). For reader 2, there was no significant difference among the three image sets (AUC, 0.848, 0.865, and 0.845; P > 0.05, respectively).

Conclusions

The diagnostic performance of 1 mSv CTE may be comparable to that of half-dose CTE.