Purpose: Grayscale ultrasound has improved the outcome of renal cell cancer (RCC), since most significant RCCs are discovered coincidently during routine abdominal ultrasound examinations. The CT scan is currently the method of choice for further evaluation. The therapeutic approach depends on the results of the CT scan. The purpose of this study was to evaluate whether RCCs would show typical vascularization patterns in contrast-enhanced ultrasonography (CEUS).
Methods and materials: We examined 30 patients with solid renal tumors before surgery with CEUS using the microbubble contrast agent SonoVue (Bracco, Italy). All patients had suspected malignant lesions on a CT scan. The examination was performed with an Acuson Sequoia (Siemens, Erlangen, Germany) with a low mechanical index (low MI) using the contrast agent imaging method "contrast pulsed sequencing" (CPS). We looked at the vascularization in the early phase (< 30 s) and the late phase (60 - 120 s). These findings were compared to the histopathological results.
Results: 25 (83 %) had an RCC, and two (7 %) patients showed an urothelial carcinoma. Benign tumors were diagnosed in three (10 %) patients. All of them were oncocytomas. In grayscale ultrasound 52 % of the RCCs were hypoechoic, 36 % isoechoic, and 12 % hyperechoic. After the application of the contrast agent, all RCCs showed a chaotic vascularization pattern. In the early phase (< 30 s), 12 tumors showed hyperperfusion, three showed isoperfusion, and nine showed hypoperfusion. During the late phase (60 - 120 s), five tumors showed hyperperfusion, nine showed isoperfusion, and ten showed hypoperfusion. One small cystic tumor did not indicate contrast enhancement at any time.
Conclusion: In our study RCC showed chaotic vascularization in CEUS without typical vascularization patterns.