Journal of Ultrasound in Medicine, Vol 20, Issue 7 723-728, Copyright © 2001 by American Institute of Ultrasound in Medicine
Deferoxamine-induced dysplasia of the knee: sonographic features and diagnostic performance compared with magnetic resonance imaging
Y. L. Chan, C. W. Chu, K. W. Chik, L. M. Pang, M. K. Shing and C. K. Li
Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin.
OBJECTIVE: To evaluate the features and diagnostic performance of
sonography in the assessment of deferoxamine-induced dysplasia of the knee.
METHODS: The left knees of 32 patients with thalassemia who were receiving
regular blood transfusions and chelation therapy were studied with
sonography for signs of deferoxamine-induced bone dysplasia. Abnormal
physeal and metaphyseal changes detected on sonography included notching at
the metaphyseal corner, a blurred or irregular peripheral juxtaphyseal
metaphyseal contour, and widening of the peripheral juxtaphyseal
metaphyseal echogenic interface. The accuracy of sonography in diagnosing
dysplasia was evaluated by using magnetic resonance imaging as the standard
of reference. RESULTS: There were 14 true-positive findings, 10
true-negative findings, 7 false-negative findings, and 1 false-positive
sonographic diagnosis of dysplasia, giving 67% sensitivity, 91%
specificity, a 93% positive predictive value, and a 59% negative predictive
value. CONCLUSION: Sonography was specific but only moderately sensitive in
the diagnosis of deferoxamine-induced dysplasia at the knee when compared
with magnetic resonance imaging.
