MRI characteristics of proctitis in Crohn's disease on perianal MRI.
Multiple features have been described for assessing inflammation in Crohn's disease (CD) in MR enterography, but have not been validated in perianal magnetic resonance imaging (MRI). Retrospectively, we studied which MRI features are valuable in assessing proctitis.



CD patients (≥18 years) who underwent colonoscopy (reference standard) and perianal fistula MRI within 8 weeks were included. Seventeen MRI features were blindly scored by three observers and correlated to endoscopy (regression analysis). Reproducibility (multirater kappa, intraclass correlation coefficient) was determined for all three observer pairs. MRI features were considered relevant when significantly correlated to endoscopy for ≥2 observers, and reproducibility was ≥0.40 for ≥2 observer pairs.



Perianal MRI of 58 CD patients were included. Wall thickness, rectal mural fat, creeping fat, and size of mesorectal lymph nodes showed a significant correlation with endoscopy for ≥2 observers (p = 0.000-0.023, p = 0.011-0.172, p = 0.007-0.011 and p = 0.000-0.005, respectively) with a kappa/intraclass correlation coefficient of ≥0.60 for ≥2 observer pairs. Perimural T2 signal and perimural enhancement significantly correlated to endoscopy (all p values ≤0.05) for all three observers and the reproducibility was ≥0.40 for ≥2 observer pairs. Mural T2 signal and degree and pattern of T1 enhancement showed significant correlation to endoscopy for two observers, but with poor to moderate reproducibility.



Wall thickness, mural fat, and mesorectal features (perimural T2 signal, perimural enhancement, creeping fat, and size of mesorectal lymph nodes) had significant correlation to endoscopy and were reproducible in diagnosing proctitis. Some established luminal features in MRE were considered not useful.
Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD, Amsterdam, The Netherlands. c.j.tuteinnolthenius@amc.uva.nl.|Department of Radiology, OLVG, PO Box 99550, 1090 HM, Amsterdam, The Netherlands. c.j.tuteinnolthenius@amc.uva.nl.
Charlotte J
CJ
Tutein Nolthenius
Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD, Amsterdam, The Netherlands.
Shandra
S
Bipat
Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD, Amsterdam, The Netherlands.
Banafsche
B
Mearadji
Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD, Amsterdam, The Netherlands.
Anje M
AM
Spijkerboer
Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE, Amsterdam, The Netherlands.
Cyriel Y
CY
Ponsioen
Department of Radiology, OLVG, PO Box 99550, 1090 HM, Amsterdam, The Netherlands.
Alexander D
AD
Montauban van Swijndregt
Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD, Amsterdam, The Netherlands.
Jaap
J
Stoker
D000328:Adult; D003113:Colonoscopy; D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011349:Proctitis / Q000000981:diagnostic imaging* / Q000473:pathology; D015203:Reproducibility of Results; D012189:Retrospective Studies
Crohn disease; Inflammatory bowel disease; Magnetic resonance imaging; Proctitis; Rectum