The value of contrast-enhanced ultrasonography in improving the diagnostic rate of renal angiomyolipoma

Objective To study the value of contrast-enhanced ultrasonography(CEUS)in the diagnosis of renal angiomyolipoma(AML).Methods The images of conventional ultrasound(US)and CEUS were retrospectively analyzed in 37 cases of renal AMLs which were confirmed by operation and pathology.The size,boundary,inner echo and color flow signals of renal tumors were observed by conventional US.Then the modality and phases of enhancement were also observed by CEUS,including the arrival time,the peak time,the washout time and the appearance of-internal structures.Results The maximum diameter range of renal lesions was from 1.7 to 28.0 cm.The tumors displayed 19 hyperechoic lesions,11 borderline hypoechoic lesions,6 mixed-echoic lesions and 1 anechoic lesions by conventional US.The color Doppler flow imaging(CDFI)showed rich flow signals in 19 cases,a small amount of flow signals in 16 cases and non-flow signal in 2 cases.The diagnostic accuracy was only 59.5%(22/37)before operation.All lesions showed mean increased start time of 13.57±3.34 seconds,peak time of 20.27±4.27 seconds,wash-out time of 28.92±5.16 seconds respectively on CEUS.In cortical phase,CEUS detected the delayed centripetal increases in 33 cases and synchronously increases in 4 cases.In peak time,compared to the normal renal cortex,hypervascular,isovascular and hypovascular enhancement appeared in 15 cases,14 cases and 9 cases respectively.The homogeneous enhancement was detected in 28 lesions.In parenchymal phase,CEUS showed isochronous washout in 11 cases,delayed washout in 19 cases and fast washout in 7 cases.Two cases displayed round pseudocapsule of lesions.The diagnostic accuracy was 75.7%(28/37)by combining delayed enhancement with homogeneous hyperechoic enhancement or isoechoic enhancement in peak time on CEUS.ConclusionsThe delayed centripetal enhancement and homogeneous hyperechoic enhancement or isoechoic enhancement in peak time on CEUS could be main features of renal AML.