The role of quantitative measurement by acoustic radiation force impulse imaging in differentiating benign renal lesions from malignant renal tumours.

PURPOSE: The purpose of this preliminary study was to prospectively evaluate the diagnostic performance of acoustic radiation force impulse (ARFI) imaging for differentiating benign lesions from malignant renal tumours.
MATERIALS AND METHODS: Sixty patients with renal lesions were enrolled in the study; mean patient age was 49.52 ± 20.46 years (range 1-83 years) and patients included 30 men and 30 women. Lesions were categorised as benign (n = 19), malignant (n = 36) and infectious (n = 5) in origin. The shear wave velocities (SWVs) of the tumours and the intact parenchyma were determined by ARFI quantification, and the differences in the SWVs were compared among groups. The final diagnoses were determined via pathologic (n = 33), clinical (n = 13) and imaging findings (n = 14). The SWV values of the renal tumours were analysed according to the final diagnoses.
RESULTS: The mean SWV value of the normal renal parenchyma was significantly different from that of all other lesions (p < 0.01). There was a significant difference between the SWV values of benign renal lesions including haematomas and the malignant renal lesions (p = 0.033). However, the SWV values of the infectious lesions and leiomyoma corresponded well with the malignant lesions. A Receiver operating characteristic (ROC) analysis demonstrated a cut-off value of 2.34 m/s between benign and malignant lesions, while sensitivity and specificity were determined to be 88 and 54 %, respectively.
CONCLUSION: ARFI elastography with ARFI quantification may be useful for differentiating benign renal lesions from malignant renal tumours.