Role of tissue harmonic imaging in characterization of cystic renal lesions

OBJECTIVE: To determine the utility of tissue harmonic imaging in evaluating cystic renal lesions and to compare these findings with conventional ultrasound guidance (USG) and CT.

METHODS: Thirty patients, detected with cystic renal lesions on routine USG (over a period of 18 months from July 2004 to December 2005 at the Postgraduate Institute of Medical Education and Research Chandigarh, Chandigarh, India) were included in this study. All patients underwent a conventional gray scale ultrasound study (GSI), followed by tissue harmonic imaging (THI) sonography on the same machine (advance technology limited high definition imaging 5000). Computed tomography of abdomen was carried out within one week of the ultrasound examinations. All images were evaluated for size, number, and location of lesions. The findings of THI sonography, conventional USG and CT of abdomen were recorded in their respective proformas. The images obtained by GSI, THI, and contrast enhanced CT were also evaluated for image quality, lesion conspicuity, and fluid-solid differentiation.

RESULTS: Tissue harmonic imaging showed better image quality in 27 of 34 lesions, improvement in lesion conspicuity was found in 27 of 34 cystic lesions, and an improved solid-fluid differentiation in 30 of 34 lesions when compared to GSI. The THI provided additional information as compared to GSI in 8 patients. The grading of CT scan was significantly higher in overall image quality (p=0.007) and lesion conspicuity (p=0.004), but was non-significant for fluid-solid differentiation (p=0.23).

CONCLUSION: Tissue harmonic imaging provides better image quality, lesion delineation, and superior characterization than conventional gray scale sonography.