Imaging findings after liver resection by using radiofrequency parenchymal coagulation devices: Initial experiences

Purpose: To retrospectively evaluate the imaging features and potential pitfalls in interpreting the findings at the site of surgery in patients undergoing hepatic resection by using the InLine and TissueLink radiofrequency devices for parenchymal coagulation prior to transection. Materials and Methods: This HIPAA-compliant study was approved by the Institutional Review Board with waiver of informed consent. Twenty-six patients (14 men, 12 women; mean age, 56 years), in whom intraoperative Inline and TissueLink devices were used for resection of hepatocellular carcinoma or metastatic liver disease or other liver tumors, were identified. Information such as tumor characteristics, diagnostic studies, surgical therapy, and surveillance methods were reviewed. All computed tomographic (CT) and positron emission tomographic (PET) scans and the single magnetic resonance and ultrasonographic images of the abdomen were retrospectively reviewed by a radiologist and compared with the initial interpreting physician's report. Results: Of 35 CT scans, 33 revealed a hypodense line of demarcation (mean thickness, 13.2 mm) between the surgical resection clips and the normal liver parenchyma. This demarcation was interpreted as "could not exclude site recurrence" in three cases and "recurrence or probable recurrence" in five cases. In two CT scans, the hypodense demarcation was not present. In all seven PET scans, the uniform hypermetabolic activity associated with the demarcation was labeled as a recurrence. At follow-up CT (median, 12.5 months), marginal recurrence was not detected in 25 patients, though in one case there was a recurrence in close proximity to the surgical site. Conclusion: The use of InLine and TissueLink devices during hepatectomy is associated with a linear hypodense demarcation at the surgical margin that also demonstrates a symmetrical rimlike hypermetabolic activity seen on PET scans.