Comparative analysis of CT-scan and PET-scan with intraoperative ultrasound (IOUS) in detecting liver metastases

Abstract

3632 Background: Open, laparoscopic or percutaneous radiofrequency ablation (RFA) has been used for the surgical treatment of liver metastases (mets). However, it requires accurate preoperative (preop) localization of liver mets. CT scan and PET scan have been widely used for such preop evaluation. However, intraoperative ultrasound (IOUS) remains the gold standard. Very little data is available comparing IOUS with preop CT and/or PET scan. Thus, a retrospective study was done to compare the efficacy of IOUS with preop CT and/or PET scan in detecting the number of liver mets. Methods: A retrospective chart review was done that included all patients (pts) who underwent surgical treatment for liver mets. Data was obtained from medical records, radiology, intraop reports. Results: 53 pts including 57% men and 43% women with a median age of 62years (age range 35–80 years) were included in the study. Imaging data was available for CT, PET and IOUS in 53, 24 and 39 pts respectively. CT, PET, and IOUS detected 2.4, 1.7 and 2.6 lesions/ pt respectively. In 24 patients, both CT and PET scan report was available. Of these, the imaging study detecting the maximum number of lesions was selected for comparison of preop evaluation with IOUS. A comparison between preop imaging (CT/PET scan) vs. IOUS in these 24 pts revealed an average of 2.3 vs. 2.8 lesions/pt respectively ( Table ). When compared with preop imaging (CT/PET scan), IOUS detected additional lesions in 33% pts; fewer lesions in 17% pts and similar number of lesions in 50% pts. Comparison between CT and IOUS in 39 patients revealed 1.9 vs. 2.6 lesions/pt respectively and that between PET and IOUS in 24 patients revealed 1.7 vs. 2.8 lesions/pt respectively. Conclusions: Although CT scan and PET scan remains effective modalities for preop evaluation of liver mets, IOUS is found to be superior for planning accurate surgical treatment. Thus, the efficacy of percutaneous RFA may be limited due to inability to perform IOUS. [Table: see text] No significant financial relationships to disclose.