ObjectiveTo investigate the diagnostic value of MRI hip joint unilateral oblique coronary scanning in the diagnosis of femoroacetabular impingement (FAI).MethodsFrom February to October 2014, 75 patients with hip joint pain who were highly suspected of FAI after X-ray or CT examination were selected as subjects. Using Siemens 1.5 T MR, fat-suppressed T2-weighted imaging sequences, T1-weighted imaging sequences, and proton density-weighted imaging sequences were used. For each patient two scan methods were used. Method A: on the sagittal image of the hip joint, the line of sight was parallel to the oblique coronal plane scan of the (one-sided) long axis of the femoral neck. Method B: on the cross-sectional image of the hip joint, the positioning line was parallel to the conventional hip joint coronal scan of the left and right femoral heads. McNemar test was used to compare the detection rates of FAI of the two methods.ResultThe detection rate of FAI of A-scanning [62.6% (47/75)] was higher than that of B-scanning [30.6% (23/75)], and the difference was statistically significant (P<0.001).ConclusionAn image obtained from a diagonal coronal scan parallel to the long axis of the femoral neck can more fully display the pathological changes of the acetabular labrum and the anatomy of the femoral head and neck joints, and the damage of the femoral head and neck junction, which provides a more reliable imaging basis for the clinician to diagnose FAI.