What are typical signs of Crohn’s disease on MR enterography ?
Segmental mural hyperenhancement and bowel wall thickening (≥3mm), usually asymmetric and more often along the mesenteric border with interspersed unaffected normal bowel segments.
What are signs of more severe inflammation in comparison to normal small bowel?
Increased hyperintensity in T2-weighted images and increased abnormality on diffusion-weighted images (DWI), in regions of Crohn’s disease-related inflammation.
What is a stricture?
A luminal narrowing in an area of Crohn’s disease with upstream dilatation (lumen>3cm).
What are pseudosacculations?
Broad-based outpouchings that usually occur in an acutely or chronically inflamed segment along the anti-mesenteric border.
Name forms of penetrating disease:
Fistulas (simple and complex), sinus tracts, inflammatory mass, abscesses.
Name extra-intestinal findings relevant to Crohn’s disease:
Sacroiliitis, primary sclerosing cholangitis (PSC), nephrolithiasis and cholelithiasis, cutaneous findings (erythema nodosum, pyoderma gangenosum), pancreatitis, avascular necrosis.
Findings:
Inflammation
segmental mural bilaminar hyperenhancement and moderate to severe asymmetric wall thickening accentuated along the mesenteric border with a corresponding hyperintense signal on T2w and high signal in diffusion-weighted images (b800)
located in the mid, distal and terminal ileum
small ulcerations
long stricture with intermittent pseudosacculations along the anti-mesenteric border in the distal ileum
Penetrating disease
sinus tracts in the ileum in the mid and left lower abdomen
no complex fistulas, abscess or an inflammatory mass
Mesenteric inflammation
signs of fibrofatty proliferation
engorged vasa recta
no signs of adenopathy
Other findings/complications
- mobile caecum cranially reverted
no signs of mesenteric venous thrombosis or occlusion
no signs of primary sclerosing cholangitis (PSC)
no gallstones or kidney stones
no signs of avascular necrosis (AVN)
Periarticular fatty deposition in the sacrum and bony bridging of the left sacroiliac joint indicative of chronic sacroiliitis
Impression:
Active inflammatory small bowel Crohn’s disease in the mid/distal and terminal ileum with luminal narrowing/strictures and ulcerations.
Small blind-ending sinus tracts can be seen in the affected segment in the left and mid-lower abdomen.
A dedicated pelvic MRI was recommended for the assessment of perianal complications.
Signs of chronic left-sided sacroiliitis.