Comparison between Diffusion-Weighted Sequences with Selective and Non-Selective Fat Suppression in the Evaluation of Crohn's Disease Activity: Are They Equally Useful?

Abstract

Background: We compared the efficiency of two MRI diffusion weighted imaging (DWI) techniques: DWI with SPIR (DWI_SPIR) and DWI with STIR (DWI_STIR), to estimate their eligibility for quantitative assessment of Crohn's disease activity in children and adults. Methods: In inflamed terminal ileum segments (n = 32 in adults, n = 46 in children), Magnetic Resonance Index of Activity (MaRIA) was calculated, ADC values of both DWI techniques were measured, and the corresponding Clermont scores calculated. ADC values of both DWI techniques were compared between both and within each patient group, assessing their mutual correlation. Correlations between MaRIA and the corresponding ADC values, and Clermont scores based on both DWI techniques were estimated. Results: No correlation between ADC of DWI_SPIR and DWI_STIR was observed (rho = 0.27, p = 0.13 in adults, rho = 0.20, p = 0.17 in children). The correlation between MaRIA and Clermont scores was strong in both techniques-in SPIR, rho = 0.93; p < 0.0005 in adults, rho = 0.98, p < 0.0005 in children, and, in STIR, rho = 0.89; p < 0.0005 in adults, rho = 0.95, p < 0.0005 in children. The correlation between ADC and MaRIA was moderate negative for DWI_STIR (rho = 0.93, p < 0.0005 in adults, rho = 0.95, p < 0.0005 in children), but, in DWI_STIR, no correlation between ADC and MaRIA score was observed in adults (rho = -0.001, p = 0.99), whereas children presented low negative correlation (rho = -0.374, p = 0.01). Conclusions: DWI_STIR is not suitable for quantitative assessment of Crohn's disease activity both in children and adult patients.

Keywords: ADC; Clermont score; DWI; DWI fat suppression techniques.; DWIBS; MR enterography; MaRIA; diffusion-weighted imaging; terminal ileitis.

Figure 1

Comparison of (a) ADC-DWI_SPIR values, and (b) ADC-DWI_STIR values between adults and children.

Figure 2

Comparison between ADC-DWI_SPIR and ADC-DWI_STIR values in the (a) adult group and (b) in children.

Figure 3

Correlation curve between ADC-DWI_SPIR and ADC-DWI_STIR in adults (a) and children (b) showing no correlation.

Figure 4

Correlation curve between MaRIA and ADC-DWI_SPIR—based Clermont score in adults (a) and children (b) showing high correlation.

Figure 5

Correlation curve between MaRIA and ADC-DWI_STIR—based Clermont score in adults (a) and children (b) showing high correlation.

Figure 6

Correlation curve between ADC-DWI_SPIR and MaRIA in adults (a) and children (b) showing moderate negative correlation.

Figure 7

Correlation curve between ADC-DWI_STIR and MaRIA in adults (a) showing no correlation and in children (b) showing low negative correlation.

Figure 8

DWI_SPIR (a) and DWI_STIR (b) tracking images of b = 800 s/mm² images of 40 years old male patient with active CD. Inflamed bowel walls present high signal intensity. Despite decreased SNR causing graininess in the images, the resolution of inflamed bowel and delineation of contours is better in DWI_STIR image (black arrow) as compared to the DWI_SPIR image (white arrow).

Figure 9

Inflammation of the ileal wall in active chronic CD in 14 y.o. boy, hematoxylin-eosin staining (courtesy of Dr. Ivars Melderis), (a) at magnification× 40, (b) at magnification× 100. Infiltration by plasma cells, neutrophils and abundant number of lymphocytes is present in the mucosal part of the bowel (star), along with epithelioid granuloma (arrow) in the lamina muscularis mucosae providing additional contribution for restricted diffusion signal in DWI images in children CD. Due to granulation process, there are unaltered red blood cells (arrowheads) in the capillaries of intestinal mucosa. The presence of blood degradation products is not detectable in any of the intestinal wall layers.