Magnetic resonance imaging in children with sickle cell disease--detecting alterations in the apparent diffusion coefficient in hips with avascular necrosis.
BACKGROUND
Avascular necrosis (AVN) is a common morbidity in children with sickle cell disease (SCD) that leads to pain and joint immobility. However, the diagnosis is often uncertain or delayed.


OBJECTIVE
To examine the ability of apparent diffusion coefficient (ADC) measurements on diffusion-weighted imaging to detect AVN in children with SCD.


METHODS
ADC values were calculated at the hips of normal children (n = 19) and children with SCD who were either asymptomatic with no known previous hip disease (n = 13) or presented for the first time with clinical symptoms of hip pathology (n = 12). ADC values were compared for differences among groups with and without AVN using non-parametric statistical methods.


RESULTS
The ADC values were elevated in the hips of children with AVN (median ADC = 1.57 × 10(-3) mm(2)/s [95% confidence interval = 0.86-2.10]) and differed significantly in pairwise comparisons (all P < 0.05) from normal children (0.74 [0.46-0.98]), asymptomatic children with SCD (0.55 [0.25-0.85]), and SCD children who had symptoms referable to their hips but did not show findings of hip AVN on conventional MRI or radiographs (0.46 [0.18-0.72]).


CONCLUSIONS
Children with sickle cell disease have elevated apparent diffusion coefficient values in their affected hips on initial diagnosis of avascular necrosis.
Department of Pediatric Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA. john.mackenzie@ucsf.edu
John D
JD
Mackenzie
Andrea
A
Hernandez
Andres
A
Pena
Kai
K
Ruppert
Dmitry
D
Khrichenko
Leonardo
L
Gonzalez
Abbas F
AF
Jawad
Lawrence
L
Wells
Kim
K
Smith-Whitley
Diego
D
Jaramillo
D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000473:pathology*; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005271:Femur Head Necrosis / Q000150:complications* / Q000473:pathology*; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult