Computed Tomography and Magnetic Resonance Enterography Findings in Crohn’s Disease: What Does the Clinician Need to Know From the Radiologist?  Carolina Pesce Lamas Constantino, MD, Rosana Souza Rodrigues, MD, PhD, Jaime Araujo Oliveira Neto, MD, Edson Marchiori, MD, PhD, Antonio Luis Eiras Araujo, MD, Renata de Mello Perez, MD, PhD, Daniella Braz Parente, MD, PhD  Canadian Association of Radiologists Journal  Volume 65, Issue 1, Pages 42-51 (February 2014) DOI: 10.1016/j.carj.2012.11.004 Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 1 A 37-year-old man with fibrostenotic-predominant Crohn’s disease coexisting with active inflammation. Coronal (A) and axial (B) computed tomography enterographic images, showing marked wall thickening associated with mural stratification (A, B, arrows). Note also the significant upstream dilatation (A, arrowhead). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 2 A 33-year-old man with Crohn’s disease. Axial T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) images without (A) and with (B) fat suppression, showing wall thickening with submucosal oedema characterized by high signal intensity on the T2 image (A, arrow) that persists on the T2 fat-suppressed image (B, arrow). Note also a small mural ulceration (A, B, arrowhead). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 3 A 55-year-old woman with mural fat deposition in long-standing Crohn’s disease. Axial computed tomography enterographic section, showing abnormally low attenuation of the bowel wall, a finding consistent with fat deposition (arrows). Note the mucosal and serosal hyperenhancement (arrowheads), which indicate a pattern of chronic disease with activity. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 4 A 65-year-old woman with mural fat deposition in long-standing Crohn’s disease. Axial T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) image (A), showing wall thickening of a small bowel segment with high signal intensity within the submucosa that loses signal intensity on an axial T2 fat-suppressed image (B), consistent with fat deposition (arrows). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 5 A 45-year-old woman with fibrostenotic-predominant Crohn’s disease and skip lesions. Axial T2 magnetic resonance (MR) image (A) and axial fat-saturation T1 MR image obtained after contrast injection (B), showing a bowel-wall stricture with low T2 signal intensity (A, B, arrow), transmural homogeneous enhancement (B, black arrowhead), and upstream dilatation (A, white arrowhead). Axial T2 MR image (C) and axial fat-saturation T1 MR postcontrast image (D) of the same patient at another level, showing a bowel-wall stricture (C, D, large arrow) with submucosal oedema (C, thin arrow), stratified enhancement (D, black arrowheads), and upstream dilatation (C, white arrowhead), which favor the diagnosis of active disease. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 6 Three enhancement patterns in Crohn’s disease. Axial fat-saturation T1 magnetic resonance images obtained after contrast injection, demonstrating (A) homogeneous enhancement of the entire wall thickness (arrow), (B) layered (stratified) enhancement, characterized by mucosal (arrowhead) and serosal (arrow) enhancement, and (C) mucosal enhancement (arrow). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 7 A 36-year-old woman with skip lesions in Crohn’s disease. Axial computed tomography enterographic section, demonstrating 2 inflammatory small bowel loops (arrows) separated by a normal segment, which is a characteristic finding of Crohn’s disease. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 8 A 28-year-old man with fibrostenotic-predominant Crohn’s disease and coexisting active inflammation. Axial computed tomography enterographic image, showing a very significant stricture with upstream dilatation (arrowhead) and mucosal hyperenhancement (arrows). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 9 A 21-year-old woman with Crohn’s disease. A coronal True fast imaging with steady-state precession (TrueFISP) image (A) and a coronal T1 postcontrast image (B), showing wall thickening of the distal ileum (A, white arrowhead) located a few centimetres from an ileocolic anastomosis (black arrowheads), with homogeneous enhancement (B, white arrowhead). Note also the prominent vasa recta characterized by short low-signal-intensity parallel lines on the T2 TrueFISP image (A), oriented perpendicular to the longitudinal axis (A, arrow), and high-signal-intensity parallel lines (B, arrow) due to contrast enhancement of the vasculature (B). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 10 A 55-year-old man with Crohn’s disease. Axial fat-saturated T2 magnetic resonance enterographic image, showing high signal intensity in mesentery adjacent to the involved ileal segment (arrow). This finding is best observed with fat suppression. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 11 A 65-year-old woman with Crohn’s disease. A coronal T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) image (A) and a coronal True fast imaging with steady-state precession (TrueFISP) image (B), showing wall thickening with deep ulceration (A, B, arrow) of the distal ileum. (C) Note the wall ulceration (arrow), and also mucosal hyperenhancement (arrowhead) on a coronal T1 postcontrast image. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 12 A 36-year-old woman with penetrating Crohn’s disease. Coronal volume-rendered computed tomography enterographic section, depicting a sinus tract (arrowhead) that originated from the terminal ileum. Note other signs of active inflammation (wall thickening and mucosal hyperenhancement) in the ileocecal valve and terminal ileum (arrow). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 13 A 42-year-old man with fibrostenotic-predominant Crohn’s disease. A complex fistula with transmural inflammation and marked upstream dilatation is evident. A coronal fat-suppressed T1 magnetic resonance image obtained after intravenous contrast administration, showing complex ileoileal (arrow) and ileocolonic (arrowhead) fistulas with diffuse enhancement of the entire wall thickness (transmural inflammation), and marked upstream dilatation. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 14 A 37-year-old man with an enterovesical fistula in Crohn’s disease. Sagittal (A) and coronal (B) computed tomography enterographic images, depicting an ileovesical fistula (white arrows) with thickening and enhancement of the bladder dome (black arrowheads). A small amount of gas is visible inside the bladder (A, white arrowhead). An ileoileal fistula with bowel-wall thickening and mural hyperenhancement is also visible (B, black arrow). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 15 A 59-year-old man with Crohn’s disease. Axial computed tomography enterographic image, depicting a complex enterocutaneous fistula with a track from the rectum to the skin (arrows) and multiple foci of cutaneous drainage (arrowheads). This patient also had ileocutaneous fistulous tracks (not shown). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 16 A 59-year-old man with known Crohn’s disease. Coronal (A) and axial (B) T2 magnetic resonance (MR) images and an axial gadolinium-enhanced fat-saturated T1 MR image (C), showing a small fluid collection with a thick, irregular, and contrast-enhanced wall, within the lower abdomen, in the mesentery adjacent to the cecum and terminal ileum, without communication with the bowel lumen (arrow). These findings are consistent with an abscess. Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 17 A 56-year-old man with multiple pseudodiverticula in Crohn’s disease. Coronal computed tomography enterographic image, showing pseudosacculations (arrowheads) produced by asymmetric thickening of the terminal ileal mesenteric border. Also note the prominence of the vasa recta (comb sign, arrows). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

Figure 18 A 46-year-old woman with long-standing Crohn’s disease. Axial computed tomography enterographic image, showing fibrofatty proliferation encircling the involved bowel loops (arrows). Note also ileal segments that display wall thickening and mural hyperenhancement, mainly in the mucosa (arrowheads). A complex ileocolonic fistula was also noted in this patient (not shown). Canadian Association of Radiologists Journal 2014 65, 42-51DOI: (10.1016/j.carj.2012.11.004) Copyright © 2014 Canadian Association of Radiologists Terms and Conditions