title: Evaluation of Crohn's disease activity by MR enterography: Derivation and histopathological comparison of an MR-based activity index.
abstract: OBJECTIVE
  To compose a qualitative magnetic resonance imaging (MRI) activity index showing Crohn disease (CD) activity, and to compare magnetic resonance enterography (MRE) findings with histopathology results.
  
  
  METHODS
  Twenty-six patients (11 male and 15 female; mean age 36.7) who had MRE and colonoscopic biopsy between October 2011 and August 2012 were included in the study. On MRE the following parameters were evaluated: bowel wall thickness, bowel wall T2 signal, bowel wall contrast enhancement pattern and degree, length and number of involved bowel segments, perimural T2 signal, mesenteric inflammation, mesenteric lymph nodes and complications of CD. Each parameter was scored to calculate MRI activity index. Biopsy specimens were retrospectively evaluated, histopathologic and endoscopic acute inflammmation scores (AIS, eAIS) were calculated. Each parameter and total MRI activity index were compared with the pathology scores (AIS, eAIS) by Mann-Whitney U test and Spearman correlation.
  
  
  RESULTS
  Statistically significant positive correlation was found between AIS and eAIS, mural thickness and eAIS. Moderate correlation was found between MRI activity index and eAIS, mural enhancement degree and eAIS; and poor correlation was found between mesenteric inflammation score and eAIS, MRI activity index and AIS, however they were not statistically significant.
  
  
  CONCLUSIONS
  In CD, bowel wall thickness measured by MRE is best correlated with the histopathologic results which are accepted as the reference standard. In cases with high MRI activity index, eAIS is also generally high. MRI activity index which is measured simply and noninvasively can be used in the follow up of CD.
authors.affiliation: Istanbul Medeniyet University Göztepe Education and Research Hospital, Radiology Department, 34722, Istanbul, Turkey. Electronic address: firdevsikbalgucer@yahoo.com.
authors.forename: Firdevs Ikbal
authors.initials: FI
authors.lastname: Gücer
authors.affiliation: Istanbul Medeniyet University Göztepe Education and Research Hospital, Radiology Department, 34722, Istanbul, Turkey. Electronic address: senem.senturk@yahoo.com.
authors.forename: Senem
authors.initials: S
authors.lastname: Senturk
authors.affiliation: Istanbul Medeniyet University Göztepe Education and Research Hospital, Radiology Department, 34722, Istanbul, Turkey. Electronic address: seymaozkanli@gmail.com.
authors.forename: Seyma
authors.initials: S
authors.lastname: Özkanli
authors.affiliation: Istanbul Medeniyet University Göztepe Education and Research Hospital, Radiology Department, 34722, Istanbul, Turkey; Kartal Yavuz Sultan Selim State Hospital, Radiology Department, Istanbul, Turkey. Electronic address: yilmabasar@gmail.com.
authors.forename: Mehmet Gökce
authors.initials: MG
authors.lastname: Yilmabasar
authors.affiliation: Istanbul Medeniyet University Göztepe Education and Research Hospital, Gastroenterology Department, 34722, Istanbul, Turkey; Hitit University Corum Education and Research Hospital, Gastroenterology Department, Corum, Turkey. Electronic address: gupseadali@gmail.com.
authors.forename: Gupse Adali
authors.initials: GA
authors.lastname: Köroglu
authors.affiliation: Istanbul Medeniyet University Göztepe Education and Research Hospital, Radiology Department, 34722, Istanbul, Turkey. Electronic address: drmacar@hotmail.com.
authors.forename: Murat
authors.initials: M
authors.lastname: Acar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002400:Cathartics / Q000008:administration & dosage; D003113:Colonoscopy / Q000379:methods; D003287:Contrast Media / Q000008:administration & dosage; D003424:Crohn Disease / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007079:Ileitis / Q000175:diagnosis / Q000473:pathology; D007089:Image Enhancement / Q000379:methods; D007413:Intestinal Mucosa / Q000473:pathology; D007422:Intestines / Q000473:pathology; D008198:Lymph Nodes / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008643:Mesentery / Q000473:pathology; D008875:Middle Aged; D062072:Patient Acuity; D010538:Peritonitis / Q000175:diagnosis / Q000473:pathology; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D002400:Cathartics; D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA
keywords: Acute inflammmation score; Crohn disease; Endoscopic acute inflammation score; Magnetic resonance activity index; Magnetic resonance enterography