Use of diagnostic dynamic contrast-enhanced (DCE)-MRI for targeting of soft tissue tumour biopsies at 3T: preliminary results.

Objectives: To test the feasibility and accuracy of MR-guided soft tissue tumour biopsy at 3T, using the dynamic contrast-enhanced (DCE) information from staging MRI for intralesional targeting.

Methods: After obtaining written informed consent for this institutional review board-approved study, 53 patients with suspected soft tissue tumours prospectively underwent preoperative staging MRI at 3T, including DCE, and subsequent MR-guided core needle biopsy. In 44/53 cases, DCE was heterogeneous and was used for intralesional biopsy targeting. Surgical, whole-specimen histology was used as the gold standard in 43/44 patients and revealed 42 soft tissue tumours (24 men; 18 women; mean age, 52 years; range, 19 - 84).

Results: Final surgical histology revealed eight benign lesions, six tumours of intermediate dignity, and 28 malignancies. All malignancies had shown heterogeneous DCE. The diagnostic yield of the biopsies was 100% (42/42). Histological accuracy rates of biopsy were 100% in predicting the dignity (42/42; 95% CI [0.916 - 1.000]), 95.2% for the tissue-specific entity (40/42; 95% CI [0.847 - 0.987]), and 90.5% for the tumour grade (38/42; 95% CI [0.779 - 0.962]).

Conclusions: Our preliminary study indicates that biopsy of soft tissue tumours can be performed accurately and safely with DCE targeted MR-guidance at 3T, using a combined staging/biopsy MRI protocol.

Key Points: • MR-guided soft tissue tumour biopsy using DCE for intralesional targeting is feasible. • Targeting by staging-MRI allows reliable planning of the biopsy approach. • The method seems accurate and safe as a combined staging/biopsy procedure in outpatients. • DCE-targeted biopsy seems useful in challenging large and heterogeneous tumours.