title: Diffusion-weighted magnetic resonance imaging of femoral head osteonecrosis in two groups of patients: Legg-Perthes-Calve and Avascular necrosis.
abstract: BACKGROUND
  The aim of this prospective study was to evaluate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) in patients with osteonecrosis. Patients were divided into two subgroups as avascular necrosis (AVN) of femoral head for adult group and Legg-Calvé-Perthes (LCP) patients for children.
  
  
  METHODS
  Seventeen patients with femoral head AVN (mean age 42.3 years) and 17 patients with LCP (mean age 8.2 years) were included in this study. Diagnosis confirmed with clinical and other imaging procedures among the patients complaining hip pain. DW images were obtained using the single-shot echo planar sequence and had b values of 0, 500, 1000 s/mm(2). The apparent diffusion coefficient (ADC) values were measured from ADC maps in epiphysis of patients with AVN, both from metaphysis and epiphysis in patients with LCP, respectively. Mann-Whitney U test was used to compare ADC values.
  
  
  RESULTS
  The mean ADC value of femoral heads (1.285 ± 0.204 × 10(-3) mm(2)/s) was increased in patients with AVN when compared to normal bone tissue (0.209 ± 0.214 × 10(-3) mm(2)/s) (p < 0.01). The mean ADC values (×10(-3) mm(2)/s) of both metaphysis (0.852 ± 0.293) and epiphysis (0.843 ± 0.332) were also increased in patients with LCP and differences were statistically significant (p < 0.01).
  
  
  CONCLUSIONS
  As a result, osteonecrosis shows increased ADC values. But it is a controversial concept that DWI offers a valuable data to conventional MRI or not. However, as there are report states, there is a correlation between the stage of the disease with ADC values in the LCP disease. DWI is a fast, without-contrast administration technique and provides quantitative values additional to conventional MR techniques; we believe DWI may play an additional assistance to the diagnosis and treatment for LCP patients. Multicentric larger group studies may provide additional data to this issue.
authors.affiliation: Sisli Hamidiye Etfal Education and Research Hospital, Radiology Clinic, Istanbul, Turkey. betulduranozel@hotmail.com.
authors.forename: Betul Duran
authors.initials: BD
authors.lastname: Ozel
authors.affiliation: Okmeydani Education and Research Hospital, Radiology Clinic, Kaptanpasa Mah. Darülaceze Cad. No:27, Okmeydanı - Şişli, 34384, Istanbul, Turkey. denizozel34@hotmail.com.
authors.forename: Deniz
authors.initials: D
authors.lastname: Ozel
authors.affiliation: Okmeydani Education and Research Hospital, Radiology Clinic, Kaptanpasa Mah. Darülaceze Cad. No:27, Okmeydanı - Şişli, 34384, Istanbul, Turkey. drfozkan@yahoo.com.
authors.forename: Fuat
authors.initials: F
authors.lastname: Ozkan
authors.affiliation: Sisli Hamidiye Etfal Education and Research Hospital, Radiology Clinic, Istanbul, Turkey. halefoglu@hotmail.com.
authors.forename: Ahmet M
authors.initials: AM
authors.lastname: Halefoglu
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005271:Femur Head Necrosis / Q000175:diagnosis*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007873:Legg-Calve-Perthes Disease / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
keywords: Apparent diffusion coefficient; Avascular necrosis; Diffusion-weighted magnetic resonance imaging; Legg–Perthes–Calve