The LungVision Navigational Platform for Preoperative Labeling of Pulmonary Ground Glass Nodules With Fiducial Markers

Lung cancer is the leading cause of cancer-related deaths, accounting for 1.8 million deaths in 2020. For this reason, early screening, diagnosis and treatment play a crucial role in improving the survival rate of lung cancer patients. The cyto-histological typing of peripheral lung nodules can be performed percutaneously (transcutaneous ultrasound or CT-guided biopsy) or bronchoscopically. The CT-guided transcutaneous biopsy approach has a diagnostic yield of over 90%, but carries a high risk of pneumothorax (up to ¼ of cases), which requires chest drainage in up to 5% of cases. The bronchoscopic approach reduces the risk of complications, but the diagnostic yield is significantly lower, ranging from 34% to 63%. The yield of the bronchoscopic approach depends on the size of the lesion (further reduced if less than 20 mm), the presence of an afferent bronchus to the nodule (bronchus sign), the location of the nodule and the experience of the operator. The LungVision system is a navigation system based on augmented fluoroscopy which, using artificial intelligence algorithms, improves the visualisation, localisation and sampling of lung nodules. The system integrates high-resolution computed tomography (HRCT) acquired pre-procedurally with real-time fluoroscopic scans during the procedure to assist the operator in locating and sampling the lesion. Overall, according to the data currently available in the literature, derived mainly from three clinical studies, a high percentage of lesion localisation (between 80 and 94.7%), a diagnostic yield varying between 75 and 87.7% and a high safety profile are reported. Attempts to biopsy the solid component of these nodules in the preoperative phase are often unfeasible or inconclusive in the clinical setting. Currently, if malignancy is highly suspected, surgical biopsy using various localisation methods is recommended. Among the possible localisation methods are the so-called "fiducial markers". These are radiopaque instruments, usually small metal bars or micro-coils, which can be placed inside or near the target lesion to facilitate its localisation during surgical resection or stereotactic radiotherapy. Fiducial markers can be placed percutaneously under CT guidance, endovascularly or, as demonstrated by recent studies, even bronchoscopically using various guidance methods safely and effectively. Bronchoscopic FM placement also offers certain advantages, including the possibility of performing biopsies on lung nodules or lymph nodes during the same session and managing any intra-procedural bleeding. Among the future prospects, one of the possible fields of application of bronchoscopic navigation associated with augmented fluoroscopy could be the placement of fiducial markers for ground glass lesions, which are often not visible with traditional fluoroscopy, given the possibility of verifying the three-dimensional location of the bronchoscope or guide catheter in relation to the target lesion (tool-in-lesion). This would avoid positioning via a more invasive route or one with a higher risk of complications, such as the transthoracic route. For these reasons, it has been hypothesised that the LungVision system, combined with radial endobronchial ultrasound, currently in use in the clinical practice of the Interventional Pulmonology Unit, could be used to locate peripheral lung lesions with a ground-glass component and place a cs-FM via bronchoscopy in the preoperative phase. This would confirm the possibility of placing the FM using the LungVision system combined with radial ultrasound, allowing for subsequent surgical removal and definitive histological typing of the target lesion.

Uncontrolled, monocentric interventional study, to be considered exploratory. Patients who meet the inclusion criteria and have given their informed consent will be enrolled consecutively. No blinding is planned. Patients will undergo bronchoscopy for cytohistological typing of GGN using a needle and/or forceps and/or cryoprobe under radial ultrasound and augmented fluoroscopic guidance, followed by immediate cytological examination in accordance with the normal clinical practice of the operating unit. In the event of cellular atypia or malignant tumour cells, the CT-FM will be placed under augmented fluoroscopic and radial ultrasound guidance to locate and mark the target lung lesion. If the immediate cytological examination is negative, the patient will be excluded from the study. If it is not possible to locate the target lesion using augmented fluoroscopy, the patient will be discharged from the study. On the same day, a chest CT scan will be performed to check the positioning of the FM. The day after the bronchoscopic procedure, the patient will undergo surgery to resect the lung lesion.

• Time to navigate to the target nodule (minutes) Time to place the fiducial marker (minutes) [Time frame: During the endoscopic procedure]
• Distance between: -fiducial marker and target lesion -fiducial marker and resection margins -target lesion and resection margins -target lesion and pleura -fiducial marker and pleura [Time frame: During histological examination of the surgical specimen (up to 1 month post surgery)]
• Time elapsed in the operating room between the start of the search for the fiducial marker using fluoroscopy and the end of the surgical resection [Time frame: During the surgical procedure]
• Proportion of lesions in which the fiducial marker is visible with intraoperative ultrasound, calculated as: (n of fiducial markers visible with intraoperative ultrasound) / n total fiducial markers [Time frame: During the surgical procedure]