Anno Graser MD, Presenter: Nothing to Disclose

Dirk-Andre Clevert MD, Abstract Co-Author: Nothing to Disclose

Christoph Richard Becker MD, Abstract Co-Author: Nothing to Disclose

Michael Staehler MD, Abstract Co-Author: Nothing to Disclose

Maximilian Ferdinand Reiser MD, Abstract Co-Author: Nothing to Disclose

Ullrich Gerd Mueller-Lisse MD, Abstract Co-Author: Nothing to Disclose

To evaluate the performance of multiphasic 64-MDCT in preoperative detection, classification and local staging of renal masses as compared to contrast enhanced ultrasound (CE-US).

A total of 40 patients (24 men, 16 women; age range, 28-79 years) was examined for evaluation of renal masses (malignant, n=35; benign, n=11) seen on conventional ultrasound. All patients underwent MDCT (Somatom Sensation 64, Siemens Medical Systems, Forchheim, Germany) at 0.6 mm collimation, reconstructed slice thickness 2 mm, 1 mm overlap. Unenhanced ultrasound (US) including B-mode and power Doppler was followed by SonoVue (2,4-4,8 ml) enhanced low MI real time US, during arterial, portal venous and delayed phases. Imaging findings were correlated with partial or total nephrectomy specimens. Performance in detection, assessment of vascularity, and local staging of malignant lesions was evaluated for MDCT and CE ultrasound. Lesion hypervascularity was rated on a five-point confidence scale. Lesion size was measured using electronic calipers. Local staging was done according to the TNM staging system. Results were tested for statistical significance using ROC curves and the Student’s t test.

Overall lesion detection rates did not differ significantly. With both imaging modalities, all 46 lesions were detected. Contrast enhanced ultrasound showed slightly better differentiation of benign versus malignant lesions, based on lesion vascularity (AUC=0.91 vs 0.88, p>0.05), but performed significantly better in predicting renal sinus fat invasion (AUC=0.93 vs 0.78, p<0.01). In local TNM staging, stage 3b (renal vein invasion) was more accurately depicted by CE-US than by MDCT (p<0.05, two-tailed t test). Lesion size was accurately measured on both imaging modalities (p=0.53, two-tailed t test).

In characterisation of complex renal masses, high-resolution MDCT remains the most important imaging modality. However, the add-on value of CE-US is seen in assessment of renal vein invasion and lesion vascularity. A combination of both modalities helps to resolve difficult cases.

Graser, A, Clevert, D, Becker, C, Staehler, M, Reiser, M, Mueller-Lisse, U, Performance of 64-slice MDCT in the Evaluation of Renal Masses: Comparison with Contrast-enhanced Ultrasound.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4411906.html