Performance of Intraoperative Contrast-Enhanced Ultrasound (Io-CEUS) in the Diagnosis of Primary Lung Cancer

Background: Suspicious tumors of the lung require specific staging, intraoperative detection, and histological confirmation. We performed an intrathoracic, intraoperative contrast-enhanced ultrasound (Io-CEUS) for characterization of lung cancer. Methods: Retrospective analysis of prospectively collected data on the application of Io-CEUS in thoracic surgery for patients with operable lung cancer. Analysis of the preoperative chest CT scan and FDG-PET/CT findings regarding criteria of malignancy. Immediately before lung resection, the intrathoracic Io-CEUS was performed with a contrast-enabled T-probe (6–9 MHz—L3-9i-D) on a high-performance ultrasound machine (Loqic E9, GE). In addition to intraoperative B-mode, color-coded Doppler sonography (CCDS), or power Doppler (macrovascularization) of the lung tumor, contrast enhancement (Io-CEUS) was used after venous application of 2.4–5 mL sulfur hexafluoride (SonoVue, Bracco, Italy) for dynamic recording of microvascularization. The primary endpoint was the characterization of operable lung cancer with Io-CEUS. Secondly, the results of Io-CEUS were compared with the preoperative staging. Results: The study included 18 patients with operable lung cancer, who received Io-CEUS during minimally invasive thoracic surgery immediately prior to lung resection. In the chest CT scan, the mean size of the lung tumors was 2.54 cm (extension of 0.7–4.5 cm). The mean SUV in the FDG-PET/CT was 7.6 (1.2–16.9). All lung cancers were detected using B-mode and power Doppler confirmed macrovascularization (100%) of the tumors. In addition, Io-CEUS showed an early wash-in with marginal and mostly simultaneous central contrast enhancement. Conclusions: The intrathoracic application of Io-CEUS demonstrated a peripheral and simultaneous central contrast enhancement in the early phase, which seems to be characteristic of lung cancer. In comparison to preoperative imaging, Io-CEUS was on par with the detection of malignancy and offers an additional tool for the intraoperative assessment of lung cancer before resection.