The role of structural-metabolic scan fusion for image-guided interventions: Biopsy of suspected malignancy

1686.6 Objectives: To determine the role and impact of PET-CT fusion on the outcome following image guided biopsies in patients with suspected malignancy. Methods: Twenty patients (8F:12M, mean age 62±15years) with suspected primary malignancy presented for CT-guided percutaneous biopsy. A whole-body Fluorodeoxyglucose (FDG)PET study was performed for staging purposes, according to the standard protocol, about an hour after the intravenous administration of 560 MBq of FDG. A diagnostic CT study was performed within 7 days of the PET scan. PET and CT reconstructed images were fused using commercial software (MiMvista, Cleveland OH). If an abnormally increased uptake of FDG was seen at the site of the biopsy, this was considered probable for an active process, for the purposes of this study. These lesions were noted to have a Standardized Uptake Value (SUV)> 2. For each patient the following parameters were reviewed to assess the impact of this approach: diagnostic imaging, pathology reports, and method and outcome of definitive diagnosis. Bayesian statistics were used to evaluate expected differences in diagnostic outcome. Results: Following conventional image-guided biopsy (namely CT), the outcomes were: true positive=12, false negative=7, true negative=1, false positive=0. If PET-CT fusion data had been used at the time of biopsy, the expected outcomes would have been 18, 1, 1, 0, respectively. This would likely have resulted in a change in the approach route in 55% (10/20), and an expected change in outcome in 30% (6/20). A definitive diagnosis was delayed an average of 93 days per patient in these 6 patients. Conclusions: Our retrospective analysis suggests that the use of fusion imaging to assist guidance of interventional procedures in patients with suspected malignancy is expected to substantially alter patient management in many settings.Also it is likely to improve diagnostic yield, reduce the delay from presentation to definitive diagnosis, and avoid unnecessary biopsies.