MR Imaging of Perianal Crohn Disease: The Role of Contrast-enhanced Sequences

The MR imaging protocol describedby the authors includes contrast-enhancedT1-weighted imaging with fatsaturation in all patients except thosewith poor renal function. Horsthuis etal demonstrated in 2009 the usefulnessof contrast-enhanced MR imagingfor determining disease activity. Contrastagent administration is also requiredin case of suspicion of neoplastictissue complicating fistulas. The jointEuropean Crohn’s and Colitis Organisation–EuropeanSociety of Gastointestinaland Abdominal Radiology guidelines report that T2-weighted images andcontrast-enhanced T1-weighted imagesare included in the MR imaging protocolfor the evaluation of perianal CD.However, as we have demonstrated, an axial T2-weighted fast spinechosequence with fat saturation, inparticular the short inversion time inversion-recovery(STIR) sequence, isa valid alternative to postcontrast T1-weighted fat-saturated imaging, allowingthe identification of the primaryfistula and any secondary ramification.