title: Is there a role for DWI in the diagnosis of sacroiliitis based on ASAS criteria?
abstract: OBJECTIVE
  Sacroiliitis based on MRI is one of the main diagnostic criteria of axial spondyloarthritis (SpA). Our purpose was to assess (a) whether apparent diffusion coefficient (ADC) values on diffusion-weighted imaging (DWI) differ between regions of bone marrow edema (BME) and subchondral normal-appearing bone marrow (NABM) in active sacroiliitis, (b) whether ADC values can differentiate early SpA and chronic SpA, both in the active and inactive phase, and (c) whether ADC values are related to laboratory findings.
  
  
  METHODS
  47 patients (24 female, 23 male, mean age: 38.53 years) with the diagnosis of SpA were included in this retrospective study. 20 age- and sex-matched subjects without SpA constituted the control group. ADC measurements were taken from all lesions and NABM of each sacroiliac joint.
  
  
  RESULTS
  A total number of 120 subchondral BME lesions (acute: 17, chronic active: 103) were noted. The mean ADC values of the BME lesions (1.30 ± 0.18 × 10(-3) mm(2)/s) were significantly higher than the ADC values in the NABM regions (0.55 ± 0.08 × 10(-3) mm(2)/s) as well as in both the control group (0.56 ± 0.05 × 10(-3) mm(2)/s) and the chronic inactive group (0.54 ± 0.03 × 10(-3) mm(2)/s). There were more BME regions in patients with chronic active sacroiliitis than early SpA patients. Correlation was found between the CRP values and ADC values.
  
  
  CONCLUSIONS
  DWI with ADC values may be complementary to FS T2-weighted or STIR MR images for accurately diagnosing inflammatory sacroiliitis. The value of DWI versus dynamic contrast-enhanced imaging in the follow-up needs to be clarified.
authors.affiliation: Department of Radiology, Sifa University School of Medicine Turkey.
authors.forename: Neslin
authors.initials: N
authors.lastname: Sahin
authors.affiliation: Department of Physical Medicine and Rehabilitation, Sifa University School of Medicine Turkey.
authors.forename: Hatice
authors.initials: H
authors.lastname: Hacibeyoglu
authors.affiliation: Department of Radiology, Sifa University School of Medicine Turkey.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Ince
authors.affiliation: Department of Radiology, Sifa University School of Medicine Turkey.
authors.forename: Aynur
authors.initials: A
authors.lastname: Solak
authors.affiliation: Department of Dermatology, Sifa University School of Medicine Turkey.
authors.forename: Belkiz
authors.initials: B
authors.lastname: Uyar
authors.affiliation: Department of Physical Medicine and Rehabilitation, Sifa University School of Medicine Turkey.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Erol
authors.affiliation: Department of Radiology, Sifa University School of Medicine Turkey.
authors.forename: Zulal Alnur
authors.initials: ZA
authors.lastname: Uslu
authors.affiliation: Department of Internal Medicine, Division of Rheumatology, Sifa University School of Medicine Turkey.
authors.forename: Senol
authors.initials: S
authors.lastname: Kobak
keywords: Active sacroiliitis; apparent diffusion coefficient; bone marrow edema; spondyloarthritis