Routine Intraoperative Ultrasound for the Detection of Liver Metastases during Resection of Primary Colorectal Cancer - A Systematic Review

Intraoperative contrast-enhanced ultrasound (CEUS) with time intensity curve (TIC) analysis for better assessment of liver tumor margins

The purpose of this study was to conduct an intraoperative evaluation of focal liver lesions using time intensity curve (TIC) analysis of contrast-enhanced ultrasound (CEUS) to better assess liver tumor margins.This study included 28 patients (21 men 75%, 7 women 25%) with malignant liver lesions (cholangiocellular carcinoma (CCC), n = 9; hepatocellular carcinoma (HCC), n = 6; hepatic metastases (HepMET), n = 13). A B-mode scan, color-coded Doppler sonography, and CEUS were performed intraoperatively to analyze the focal lesions. The generated parametric images were based on continuous cine loops, acquired with a multifrequency T-probe (6-9 MHz), from the early arterial phase (0-15 seconds) to the portal venous phase (1 minute), generated by integrated perfusion software. Analyses of the CEUS loops were performed using TICs with respect to time-to-peak (TTP) and area under the curve (AUC). Perfusion analysis was performed in the center and periphery of the tumor as well as in healthy liver tissue. All tumor lesions were evaluated histopathologically to verify the diagnosis.Sufficient image quality was achieved in all cases using CEUS for TIC analysis. A comparison of all groups showed a clear difference compared with the center, margin, and healthy liver tissue in the measured parameters of TTP and AUC (p = 0.035 and p = 0.045, respectively). In detail, differences were observed in the CCC group (TTP: p = 0.025) and in the HepMET group (TTP: p = 0.009), particularly in the peripheral areas (strong arterial flooding with a rapid increase in the flooding curve), with equally clear tumor edge representation compared with healthy liver tissue, as shown by the AUC analysis (CCC AUC: p = 0.032 and HepMET AUC: p = 0.029). In patients with HCC, the perfusion pattern (starting from the center) showed the center to be more clearly distinguishable from the edge with significant TTP and AUC (p = 0.035 and p = 0.038).Intraoperative TIC analysis of malignant liver tumors is an important diagnostic tool for better highlighting liver tumor margins during surgery. · CEUS with dynamic vascularization. Analysis of liver malignancies and tumor margins. Intraoperative time intensity curve analysis.. · Dropco I, Kaiser U, Jung F et al. Intraoperative contrast-enhanced ultrasound (CEUS) with time intensity curve (TIC) analysis for better assessment of liver tumor margins. Rofo 2025; DOI 10.1055/a-2600-7229.

Impact of laparoscopic ultrasound during PIPAC directed treatment of unresectable peritoneal metastasis

Objectives

Laparoscopic ultrasound (LUS) combines both laparoscopy and ultrasound imaging of the peritoneum liver and retroperitoneum. LUS has not been described in treatments with pressurized intraperitoneal aerosol chemotherapy (PIPAC). We present our experience with LUS in patients undergoing PIPAC.

Methods

Retrospective study of LUS findings from the prospective PIPAC-OPC2 trial. Main outcome was changes in overall treatment strategy due to LUS findings.

Results

PIPAC-OPC2 included 143 patients of which 33 patients were treated with electrostatic precipitation PIPAC. Nine patients were excluded due to primary non-access. During PIPAC 1, LUS was performed in 112 of 134 (84 %) PIPAC procedures and changed overall treatment strategy in one patient due to detection of multiple liver metastases unseen by baseline CT. During PIPAC 2 and 3 LUS was performed in 59 of 104 (57 %) and 42 of 78 (54 %) PIPAC procedures, respectively. Throughout PIPAC 1-3, LUS also detected pathological lymph nodes in 16 patients, and focal liver lesions in another four patients of uncertain origin. No further examinations were performed in these patients, and the overall treatment strategy was not changed according to the PIPAC-OPC2 protocol. One patient had a splenic capsule rupture related to the LUS itself. This was managed conservatively.

Conclusions

LUS may be safely performed during PIPAC. However, LUS has limited clinical impact in patients scheduled for PIPAC, and cannot be recommended as a routine procedure when performing PIPAC.

Increasing utilization of contrast-enhanced ultrasound during abdominal biopsies: impact of an educational training program

RATIONAL AND OBJECTIVES

To increase utilization of contrast-enhanced ultrasound (CEUS) during ultrasound-guided targeted liver biopsies.

MATERIAL AND METHODS

Two educational training interventions performed to increase use of CEUS. First, 14 radiologists (fellowship-trained in Abdominal Imaging) given didactic teaching and case presentations on the use of CEUS. Second, hands-on teaching on how to use CEUS provided to the same group. To determine the efficacy of these two interventions, radiologists completed anonymous surveys to determine the level of understanding and acceptability of using CEUS before and 6 months after CEUS training. In addition, the percentage of CEUS assisted liver biopsies was compared for the 6 months before and 6 months after the training.

RESULTS

Pre-training survey completed by 11 radiologists and post-training survey completed by 9 radiologists. Before training, 11% survey responders use CEUS routinely, whereas 89% never or rarely used it. After training, 54% of respondents were new users and 100% reported they planned to use CEUS in the future. Unfamiliarity (71%) was the main reason for not using it. After training, 25% reported lack of comfort with using CEUS as the main reason for not using CEUS. During six months before training, CEUS was administered in 6% (10/172) of targeted liver biopsies. Six months after training, CEUS was used nearly twice as often (10%, 16/160, P = 0.09, 1-sided Boschloo test). The number of radiologists using CEUS increased to 57% (8/14) after training compared to 20% (3/14, P = 0.03, 1-sided Boschloo) before training.

CONCLUSION

Educational training intervention increases use of CEUS during ultrasound-guided targeted liver biopsies.

Automatic hepatic tumor segmentation in intra-operative ultrasound: a supervised deep-learning approach

Purpose

Training and evaluation of the performance of a supervised deep-learning model for the segmentation of hepatic tumors from intraoperative US (iUS) images, with the purpose of improving the accuracy of tumor margin assessment during liver surgeries and the detection of lesions during colorectal surgeries.

Approach

In this retrospective study, a U-Net network was trained with the nnU-Net framework in different configurations for the segmentation of CRLM from iUS. The model was trained on B-mode intraoperative hepatic US images, hand-labeled by an expert clinician. The model was tested on an independent set of similar images. The average age of the study population was 61.9 ± 9.9 years. Ground truth for the test set was provided by a radiologist, and three extra delineation sets were used for the computation of inter-observer variability.

Results

The presented model achieved a DSC of 0.84 (p = 0.0037 ), which is comparable to the expert human raters scores. The model segmented hypoechoic and mixed lesions more accurately (DSC of 0.89 and 0.88, respectively) than hyper- and isoechoic ones (DSC of 0.70 and 0.60, respectively) only missing isoechoic or >20 mm in diameter (8% of the tumors) lesions. The inclusion of extra margins of probable tumor tissue around the lesions in the training ground truth resulted in lower DSCs of 0.75 (p = 0.0022 ).

Conclusion

The model can accurately segment hepatic tumors from iUS images and has the potential to speed up the resection margin definition during surgeries and the detection of lesion in screenings by automating iUS assessment.

Determination of the diagnostic efficiency of contrast-enhanced ultrasound in the diagnosis of liver metastases of colorectal cancer

ABSTRACT