[Comparative study of ultrasound and magnetic resonance imaging in the diagnosis of asymptomatic anterosuperior acetabular labrum tears].

OBJECTIVE

To explore the diagnostic value of ultrasound for asymptomatic anterosuperior acetabular labral tears (ALT).

METHODS

From August 2018 to February 2020, a total of 64 asymptomatic volunteers (101 hips) were recruited to complete 3.0T magnetic resonance imaging (MRI) and ultrasound examination. Among these asymptomatic volunteers, 31 were male and 33 were female, with the median age 35 (32, 39) years. Using 3.0T MRI findings as golden standard, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ultrasound were calculated.

RESULTS

The results showed the presence of unilateral or bilateral ALT in 33 (51.56%) asymptomatic vo-lunteers with a total of 47 hips (46.53%). Of the 37 asymptomatic volunteers with bilateral hip MRI examination, 14 had bilateral ALT and 8 had unilateral ALT. Of the 27 asymptomatic volunteers who underwent unilateral hip MRI, 11 had ALT. Of the 33 asymptomatic volunteers with labral tears, 11 were male and 22 were female, with 30 right hips and 17 left hips. The median age was 36 (33, 40) years in the ALT group and 34 (32, 38) years in the non-ALT group. There was no significant difference in age between the two groups ( > 0.05). In the asymptomatic population, the abnormal anterosuperior acetabular labrum manifestations on ultrasound were intra-labrum cleft in 26 cases, labral heterogeneous echogenicity in 25 cases, paralabral cysts in 2 cases, and labral focal hyperechoic area in 12 cases. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for ALT diagnosed by ultrasound were 73.53%, 67.16%, 53.19%, 83.33% and 69.31%, respectively. The cross- sectional area (CSA) of the anterosuperior acetabular labrum was 0.20 (0.15, 0.24) cm in this study. The labral median CSA of the ALT group and non-ALT group were 0.22 (0.17, 0.28) cm and 0.17 (0.14, 0.21) cm, respectively, with a statistically significant difference ( < 0.001).

CONCLUSION

The ALT are common findings in asymptomatic volunteers on MRI. Intra-labrum cleft and labral heterogeneous echogenicity are common ultrasonographic signs in asymptomatic volunteers with ALT. The labra were more swollen in the asymptomatic volunteers with ALT compared to those without ALT.