[Potential uses of color Doppler in periskeletal soft tissue neoplasms]

Integrated imaging plays a fundamental role in the study of periskeletal soft tissue tumors, for both diagnosis and treatment planning. The steady and progressive technologic progress of color Doppler US equipment now permits the integration of conventional morphostructural parameters with the biofunctional data of lesion flow patterns and relative qualitative features. To assess color Doppler capabilities in differentiating benign from malignant soft tissue tumors, we reviewed the B-mode and color Doppler findings of 43 consecutive patients with a palpable periskeletal soft tissue mass. All patients were examined with a real time unit (Ultramark 9 HDI), with a broadband (5-10 MHz) linear transducer operating at 6.5 MHz for Doppler measurements. The PRF was set at 1500 to 800 Hz with 70% color gain; a 100 Hz wall filter was used. We kept the color box in the area of interest as small as possible to keep the frame rate high; pulsed Doppler studies were performed with a small sample volume and 2000 Hz PRF. The following signs were considered: morphostructural features; the presence/absence of color signals; the (peripheral/internal) site of vascular branches, their caliber and course; the number of afferent vascular poles; resistance index. As a rule, malignant masses tend to differ from benign masses for the presence of multiple vascular afferent branches, especially if they have an irregular pattern and caliber, and for the variability of the resistance index measured in different parts of the same mass. Further examinations, performed with second level imaging (CT and MRI) and microhistologic tests, respectively after biopsy and surgical resection, confirmed the high predictive value of color Doppler US, with only 1 false negative and 2 false positives; color Doppler sensitivity and specificity were 94.7% and 91.6%, respectively, which are higher values than those obtained with US alone (63% and 66.6%). Therefore, we believe that color Doppler US can be systematically applied to the study of periskeletal soft tissue masses, integrating conventional US for the correct selection of the patients to be submitted to second level investigations.