Acute fracture of the femoral neck: assessment of femoral head perfusion with gadopentetate dimeglumine-enhanced MR imaging.

OBJECTIVE

Evaluation of the perfusion and viability of the femoral head after fracture of the femoral neck is important because the outcome of conservative treatment or joint-preserving surgery is adversely affected by the development of capital osteonecrosis. We evaluated the use of MR imaging, before and after IV administration of gadopentetate dimeglumine, for assessing perfusion of the femoral head in 13 patients with acute fracture of the femoral neck.

SUBJECTS AND

METHODS

Multiecho (1600/30-240 [TR/TE]) MR images were obtained before contrast administration and gradient-echo (315/14, 90 degrees flip angle) MR images were obtained both before and after contrast administration. MR findings were correlated with findings on superselective digital subtraction angiograms of the vessels supplying the femoral head and with clinical-radiographic follow-up for at least 12 months.

RESULTS

Digital subtraction angiography showed impaired blood supply to the femoral head in five patients. On contrast-enhanced MR images of these patients, the femoral head did not enhance and was lower in signal intensity than were the enhancing femoral shaft and neck distal to the fracture and the enhancing femoral head on the unaffected side. In the patients with persistent perfusion, contrast-enhanced MR images showed a uniform increase in signal intensity in the femoral shaft and neck as well as the femoral head; the femoral head on the fractured side showed contrast enhancement similar to that on the healthy side.

CONCLUSION

These preliminary results indicate that contrast-enhanced MR imaging may be useful for noninvasive evaluation of femoral head perfusion after fracture of the femoral neck. MR findings also may aid the clinician in deciding between joint-preserving therapy and hip arthroplasty.