Feasibility of Magnetic Resonance Angiography in Patients With Legg-Calvé-Perthes Disease.

BACKGROUND: The etiology of Legg-Calvé-Perthes disease (LCPD) remains unknown; however, interruption of medial circumflex femoral artery (MCFA) supply to the femoral head is the key pathogenic factor. The main purpose of this study is to determine the feasibility of using magnetic resonance angiography (MRA) to evaluate the course of the MCFA in the normal and affected hips of patients with unilateral LCPD.

METHODS: We analyzed 24 patients with unilateral LCPD using a time-resolved imaging of contrast kinetics magnetic resonance angiography (TRICKS-MRA). The course of the MCFA was divided into 4 segments in the coronal plane and in 3 segments in the axial plane, based on its location with respect to the femoral neck. The visibility of each segment was studied in the normal and affected sides. The segments were defined as not visible when no contrast was seen within the vessel lumen or visible when the lumen was partially or completely visualized with contrast. The statistical analysis was done using the χ2 test.

RESULTS: TRICKS-MRA provided well-defined images of the first 2 segments of the MCFA on both the normal and affected sides of patients with LCPD (P=1). In half of the patients, the third segment was also visible using TRICKS-MRA on both sides (P=1). The fourth segment of the MCFA, which was the ascending lateral epiphyseal segment, was not visible on either side (P=0.49). No significant difference was found between the normal and affected hips in terms of visibility of the 4 segments of the MCFA using TRICKS-MRA. Anastomosis of the MCFA with the inferior gluteal artery was found in 3 hips (2 hips with LCPD and 1 normal hip).

CONCLUSIONS: TRICKS-MRA provides well-defined images of the arterial supply to the proximal femoral epiphysis in children with LCPD, presenting a noninvasive and radiation-free alternative to conventional angiography. However, the TRICKS-MRA method used did not allow visualization of the ascending lateral epiphyseal segment of MCFA in the affected and the contralateral normal side. We believe that further advancement of this noninvasive imaging technique may open new opportunities for research aimed at evaluating the vascular supply of the femoral head in children.

LEVEL OF EVIDENCE: Level IV-case-control study.