Intra-operative contrast-enhanced ultrasound improves image enhancement in the evaluation of liver tumors

Feasibility of Contrast-Enhanced Intraoperative Ultrasound for Detection and Characterization of Renal Mass Undergoing Open Partial Nephrectomy

OBJECTIVES

To determine the feasibility of obtaining intraoperative contrast-enhanced ultrasound (CEUS) imaging in patients undergoing open partial nephrectomy for renal cancer. We hypothesize that the study was feasible and the addition of CEUS would improve lesion identification and characterization.

METHODS

The study population consisted of 10 patients with known renal mass scheduled for intraoperative ultrasound-guided open partial nephrectomy. After dissection and exposure of the kidney by the surgeon, an intraoperative pre- and post-CEUS was performed by the radiologist. Feasibility was defined as successful imaging in 8 of 10 patients with intraoperative CEUS. Image quality, lesion conspicuity/contrast, lesion vascularity, morphology, and size were assessed and graded with pre- and post-contrast images.

RESULTS

Intraoperative ultrasound was successfully acquired in 10 of 11 patients for renal mass detection and characterization. One study was canceled intraoperatively as a result of clinical complications related to a difficult surgery. Tumor size ranged from 1.3 to 4.2 cm. All lesions were solid. No additional lesions were found on CEUS compared with baseline imaging. Image quality post-contrast ranged from acceptable to excellent. There were no adverse events recorded for all 10 patients.

CONCLUSIONS

In our feasibility study consisting of 10 patients, CEUS for detection and characterization of renal mass undergoing open partial nephrectomy was feasible and safe. Because intraoperative ultrasound during open partial nephrectomy can affect the extent of surgery, CEUS can be used to help detect and characterize renal mass for surgical planning/resection intraoperatively.

Risk factors and management of conversions to an open approach in laparoscopic liver resection: analysis of 265 consecutive cases

BACKGROUND

As a consequence of continuous technical developments in liver surgery, laparoscopic liver resection (LLR) is increasingly performed worldwide.

METHODS

Between January 2004 and December 2011, 265 LLR were performed in 242 patients for various diseases. The experience of LLR is reported focusing on risk factors of conversion and their management.

RESULTS

The overall conversion rate was 17/265 (6.4%), equally distributed over the period of the study. Statistically significant factors for conversion were found to be LLR of the postero-superior (P-S) segments (SI, SIVa; SVII; SVIII) (12.7% converted versus 2.5% non-converted groups, P = 0.01) and a major compared with a minor hepatectomy (15.2% vs. 4.6%, P = 0.02 respectively). A R0 resection was achieved in 93.2% of cases. According to Dindo's classification, complications were recorded as grade I (n = 20); grade II (6); grade III (11) and grade IV(1) events (total morbidity rate of 14%). Univariate analysis identified a major hepatectomy and resection involving P-S segments as prognostic factors for conversion whereas multivariate analysis identified the latter as an independent risk factor [P = 0.003, odds ratio (OR) = 5.9, 95% confidence interval (CI) = 1.8-18.8].

CONCLUSIONS

LLR can be safely performed with low overall morbidity. According to this experience and irrespective of the learning curve, resections of P-S segments were identified as an independent risk factor for conversion in LLR.

Contrast-enhanced ultrasound in the preoperative, intraoperative and postoperative assessment of liver lesions

The use of contrast agents (CA) with liver ultrasound (US) has gained recently an established role for the diagnosis of various hepatic diseases due to their safety, high versatility and low costs (contrast-enhanced ultrasound: CEUS). The purpose of this review is to provide a state-of-the-art summary of the available evidence for their use in the characterization of focal liver lesions. A published work search was conducted for all preclinical and clinical studies involving CA on hepatic US imaging. CEUS increases the sensitivity for lesion detection and the specificity to differentiate between benign and malignant diseases due to the enhanced visualization of the tumor microcirculation. Results achieved seem at least equivalent to those of spiral computed tomography or magnetic resonance imaging. The association of CA with intraoperative ultrasound has changed the surgical approach in 25% of patients and guarantees complete ablations by a single session in most of them. CEUS provides detailed information about tumor vasculature, improves the preoperative characterization and therefore the therapeutic strategy, and can evaluate the intraoperative completeness of the ablation.

Incomplete thermal ablation of hepatocellular carcinoma: effects on tumor proliferation

INTRODUCTION

Local recurrence after thermal ablation of hepatocellular carcinoma (HCC) is common, problematic, and poorly understood. The continued effects of the heat sink around major vessels have been hypothesized to increase local ablation failure and possibly enhance the growth of the incompletely ablated malignancy. The aim of this study was to evaluate the critical temperature to which incomplete ablation would occur.

METHODS

Established murine (Hep-6L), rodent (Hep-4IIE), and human (Hep-G2) HCC cells were cultivated and then exposed to variable 2° temperatures from 37 °C-54 °C and incubated at 37 °C for 72 h. After incubation, 3-(4, 5-dimthyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assays were used to measure proliferation, metabolic activity, and apoptosis.

RESULTS

Reliable cell death occurred in all three cell lines by microscopy and MTT assay after treatment at temperatures above 48 °C. However, in the 72 h after treatment, we observed successive recovery or maintenance of cellular proliferation at each time endpoint at ≤47 °C. This effect was present across all cell lines at 45 °C, and was most pronounced in the Hep-6L and Hep-4IIE cell lines (P < 0.05). Hep-G2 cells demonstrated maintenance of proliferation by MTT assay over the 72 h following treatment at 45 °C. TUNEL assays were strongly positive at temperatures ≥48 °C. TUNEL positivity suggests death via apoptotic mechanisms as opposed to coagulative processes seen at higher temperatures. Cells treated at these higher temperatures had a statistically significant (P < 0.05) higher apoptotic index as measured by TUNEL positivity, despite being morphologically similar by light microscopy.

CONCLUSIONS

Cellular proliferation and resistance to apoptosis are significantly increased after incomplete thermal ablation, with a 2° difference in complete versus incomplete ablation.