Identification of Glisson's Capsule Invasion During Hepatectomy for Colorectal Liver Metastasis by Contrast-Enhanced Ultrasonography Using Perflubutane.

Background: Glisson invasion by CLM is associated with a risk of margin-positive resection, leading to poor long-term outcomes after hepatectomy. This study was performed to evaluate the efficacy of intraoperative ultrasonography (IOUS) for the diagnosis of Glisson's capsule invasion by colorectal liver metastasis (CLM).
Methods: This prospective study involved 50 consecutive patients undergoing hepatectomy for CLM. Preoperatively, all patients had undergone gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI). During hepatectomy, a contrast agent (perflubutane) was intravenously injected and Glisson invasion was estimated based on three characteristic findings: a tumor thrombus, peripheral dilatation, and border irregularity/caliber change. The diagnostic abilities of the preoperative and intraoperative imaging studies were evaluated based on pathological examinations of resected specimens.
Results: Among 187 CLMs resected, pathological examinations proved Glisson invasion in 24 tumors (13%). IOUS revealed a tumor thrombus in 3 tumors (1.6%), peripheral dilatation in 4 (2.1%), and border irregularity and/or caliber change in 24 (12.8%). The sensitivity and specificity of IOUS with any of the above three findings for diagnosis of Glisson invasion was 79% and 96%, respectively, while preoperative EOB-MRI detected Glisson invasion in only four tumors (sensitivity/specificity, 17%/100%). The cutoff value of caliber change for diagnosis of Glisson invasion was set at 140% by receiver operating characteristic analysis. The R0 resection rates were not significantly different between patients with (82%) and without (85%) Glisson invasion.
Conclusions: Identification of characteristic findings (tumor thrombus, peripheral dilatation, and border irregularity/caliber change) by contrast-enhanced IOUS is useful for the prediction of Glisson invasion by CLM.