The role of sonoelastography in planning percutaneous biopsy of soft tissue tumours.

Abstract

The aim of this study was to evaluate whether compression elastography has a useful role in the planning of percutaneous ultrasound-guided biopsies of soft tissue tumours. Consecutive patients were evaluated in the sarcoma clinic after their initial imaging work-up, involving ultrasound and MR. The multi-disciplinary team decided when percutaneous biopsy for histology was required, and this was performed in the multi-disciplinary clinic using ultrasound guidance. An experienced sarcoma radiologist performed the ultrasound with compression elastography in all cases. Grey scale imaging was used to predict the needle track for each biopsy and routinely, two passes were made into each lesion. In this study, the track for the second pass was predicted from the elastogram, aiming for a stiff (blue) area within the lesion. The samples were separately potted in formalin and sent to the sarcoma pathologist. Pathology reports for each sample were assessed to evaluate whether the elastographic blue targets yielded any specific diagnostic quality; 157 biopsies were performed in separate patients, including two passes per patient as per routine protocol; 107 (68.1%) were benign lesions and 50 (31.9%) were malignancies. In the benign group, 16 (14.9%) showed significant blue areas in the lesion. However, nine of these were thought to be artefactual, as they showed grey scale characteristics of complex cysts. Positive histology was recorded in all the blue areas, but in the benign lesions positivity was not seen solely in the blue areas; 14 (28%) in the malignant group showed blue areas in the lesion and five biopsies were positive in blue areas only. Overall, the blue target yielded the only positive tissue in 10% of the malignancies, equating to 3% of the whole study population. The p value was 0.008829 for positive histology for malignancy from blue areas only.