Evaluating luminal and post-operative Crohn’s disease activity on magnetic resonance enterography: A review of radiological disease activity scores

Table 2 Defining radiologic findings on magnetic resonance enterography in Crohn’s disease[19,21,28,42,44,97-105]

Radiological item	Definition
Mural thickening[97]	Increased bowel wall thickness; > 3 mm generally considered abnormal
Mural oedema[98]	Mural hyperintensity on T2-weighted fat-suppressed image
Peri-mural oedema/fat stranding[19]	Loss of distinction between the bowel wall and mesentery with hyperintensity or fluid in the mesenteric fat on T2-weighted fat-suppressed image
Mural contrast enhancement[99]	Mural hyperintensity post intravenous contrast administration on T1-weighted image
Mesenteric lymphadenopathy[100]	Enlargement of mesenteric lymph nodes
Ulceration[101]	Mucosal based defect in the bowel wall filled with oral contrast material or enteric contents
Mural contrast enhancement pattern[98]	Pattern of bowel wall contrast enhancement categorised as homogenous, mucosal or layered on post intravenous contrast T1-weighted image
Stricture[19]	Luminal narrowing with pre-stenotic dilatation (≥ 3 cm) where luminal narrowing is defined as a reduction in luminal diameter of ≥ 50% compared to normal adjacent bowel
Probable stricture[42]	Luminal narrowing without pre-stenotic dilatation (< 3 cm) where luminal narrowing is defined as a reduction in luminal diameter of ≥ 50% compared to normal adjacent bowel
Comb sign[102]	Engorgement of the vasa recta with the appearance resembling a comb
Fistula[101]	Abnormal communication tract between the bowel and another epithelial surface
Diffusion-weighted imaging hyperintensity[28]	Hyperintensity on diffusion-weighted imaging identifies intestinal regions with restricted fluid diffusion
Apparent diffusion coefficient[28]	Quantitative assessment of the regional fluid movement using diffusion-weighted imaging
Abscess[103]	A collection of fluid characterised by border enhancement on post intravenous contrast T1-weighted image and central fluid hyperintensity on T2-weighted image
Disease length[44]	Quantitative measurement of the length of the diseased bowel
Creeping fat[19]	Increased presence of adipose tissue surrounding the diseased bowel segment
Haustral loss[105]	Loss of haustral folds in the colon resulting in a featureless colon