Quantitative DCE-MRI assessment of femoral head epiphysis perfusion after closed reduction in developmental dysplasia of the hip.

Abstract

To investigate femoral head epiphysis perfusion via dynamic contrast-enhanced MRI (DCE-MRI) in children with developmental dysplasia of the hip (DDH) after closed reduction, assessing correlations between perfusion parameters and enhancement grades, and their utility in identifying post-reduction ischemia. Children with DDH undergoing closed reduction and plaster fixation were evaluated with MRI (conventional sequences, T1 mapping, and DCE-MRI) within 3 days post-procedure. Femoral head perfusion was evaluated using DCE-MRI subtraction, graded as 0 (normal), 1 (asymmetric decrease), 2 (focal decrease), or 3 (complete decrease). Perfusion parameters (K^trans, K_ep, V_e) were quantified in the epiphyseal ROI. The correlation with perfusion grades and diagnostic value for ischemia was analyzed. The study included 58 DDH patients (116 hips; 68 dislocated, 48 normal). Among the dislocated side of DDH, although a marginal age difference was observed among the groups (P = 0.053), no significant differences were found in sex distribution or Tönnis grade (P > 0.05). Significant perfusion parameter differences were observed across enhancement grades (all P < 0.05), with K^trans showing greatest discrimination (H = 89.769). K^trans and K_ep correlated negatively with enhancement grade (r = -0.883 and -0.608, respectively; both P < 0.001). For ischemia detection (grade ≥ 2), K^trans demonstrated superior diagnostic accuracy (AUC = 0.959, cutoff = 0.028 min^-1) versus K_ep (AUC = 0.811) and V_e (AUC = 0.628). Performance further improved for grade 3 ischemia (K^trans AUC = 0.992, cutoff = 0.010 min^-1). K^trans < 0.010 min^-1 on DCE-MRI signals post-reduction ischemia in dislocated femoral heads, inversely correlating with enhancement grade. This threshold may help identify high-risk patients requiring close monitoring or intervention.