title: Association between apparent diffusion coefficient and intervertebral disc degeneration in patients with ankylosing spondylitis.
abstract: OBJECTIVE
  To assess the relation between ankylosing spondylitis (AS) and degenerative disc disease emerging in association with various intrinsic and extrinsic factors and to evaluate the correlation between degree of degeneration in intervertebral discs and apparent diffusion coefficient (ADC) values.
  
  
  METHODS
  Thirty-five patients with AS and a control group of 35 patients were included in the study. Three hundred fifty intervertebral discs were assessed in terms of degeneration by analyzing signal intensities and morphologies on T2 weighted series of a 1.5 Tesla magnetic resonance scanner. ADC values were determined in diffusion weighted images (DWI) using a "b value of 500 s/mm(2)". Patients in the AS and control groups were compared in terms of intervertebral disc degeneration, and association between degree of degeneration and ADC values was analyzed.
  
  
  RESULTS
  The mean of total degeneration degrees for five lumbar intervertebral discs was significantly higher in the patients with AS compared to the control group (16.77±4.67 vs 13.00±4.08, respectively; P=0.001). When intervertebral discs were analyzed separately, disc degeneration was again significantly higher in patients with AS compared to the control group, with the exception of L5-S1. Age, cholesterol level, triglyceride level, duration of disease and BASFI index were significantly associated with degree of degeneration in patients with AS. A negative correlation was determined between disc degeneration and ADC value.
  
  
  CONCLUSIONS
  AS is a risk factor for degenerative disc disease due to its systemic effects, the fact it leads to posture impairment and its inflammatory effects on the vertebrae. A decrease in ADC values is observed as degeneration worsens in degenerative disc disease.
authors.affiliation: Department of Radiology, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Resorlu
authors.affiliation: Department of Physical Medicine and Rehabilitation, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Ferhat
authors.initials: F
authors.lastname: Gokmen
authors.affiliation: Department of Physical Medicine and Rehabilitation, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Hatice
authors.initials: H
authors.lastname: Resorlu
authors.affiliation: Department of Radiology, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Gurhan
authors.initials: G
authors.lastname: Adam
authors.affiliation: Department of Physical Medicine and Rehabilitation, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Ayla
authors.initials: A
authors.lastname: Akbal
authors.affiliation: Department of Public Health, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Sibel
authors.initials: S
authors.lastname: Cevizci
authors.affiliation: Department of Radiology, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Sariyildirim
authors.affiliation: Department of Physical Medicine and Rehabilitation, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Yilmaz
authors.initials: Y
authors.lastname: Savas
authors.affiliation: Department of Neurosurgery, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Guven
authors.affiliation: Department of Neurosurgery, Canakkale Onsekiz Mart University, Faculty of Medicine Canakkale, Turkey.
authors.forename: Adem Bozkurt
authors.initials: AB
authors.lastname: Aras
keywords: Ankylosing spondylitis; apparent diffusion coefficient; intervertebral disc degeneration; magnetic resonance imaging