Quantitative Evaluation of Noncontrast Magnetic Resonance Enterography for Active Inflammation in Crohn Disease Using Native T 1 and T 2 Mapping.

Abstract

Purpose: The aim of this study was to investigate the utility of native T 1 and T 2 mapping in the bowel to evaluate disease activity in Crohn disease (CD) using endoscopy as the reference standard.

Methods: This was a prospective study. Magnetic resonance imaging was performed by using a 1.5-T Philips scanner. We used a modified look-locker inversion recovery and a multiecho gradient-spin-echo sequences for single breath-hold native T 1 and T 2 maps, respectively, for the short-axis image of the intestine, and the measurement at the most severe site was compared with partial Simple Endoscopic Score for Crohn's Disease (pSES-CD, assessed by an expert endoscopist). A pSES-CD ≥ 4 indicated active disease. Statistical analyses were performed using the Student t test, Spearman correlation, and receiver operating characteristic curve analysis.

Results: A total of 27 patients (mean age ± standard deviation, 37 ± 18 years; 20 men, 7 women) were included in this study. The native T 1 value of active disease was significantly higher than that of inactive disease (1170.8 ± 100.5 milliseconds vs 924.5 ± 95.3 milliseconds; P = 0.018), but the T 2 value was not significantly different between active and inactive disease (76.1 ± 7.8 milliseconds vs 69.3 ± 10.9 milliseconds; P = 0.424). A good correlation was found between native T 1 value and pSES-CD (ρ = 0.71; P < 0.001) but not between T 2 value and pSES-CD (ρ = 0.06; P = 0.790). The area under the receiver operating characteristic curve for differentiating the disease activity was 0.96 (95% confidence interval [CI]: 0.90-1.00) for T 1 values and 0.68 (95% confidence interval: 0.41-0.96) for T 2 values.

Conclusions: Native T 1 mapping could be potentially used as a noninvasive method to differentiate disease activity in patients with CD and may be superior to T 2 mapping for this purpose.