Efficacy and Safety of CT-Guided Patent Blue Injection to Localize Deep Pulmonary Nodules of the Thorax

Background and Objectives: The needle path is crucial for preoperative localization of deep thoracic pulmonary nodules using CT-guided patent blue dye (PBD) injection. This study aimed to evaluate the efficacy and safety of four categorized needle approach paths tailored to the anatomical location of the nodules. Materials and Methods: We retrospectively evaluated data from 50 consecutive patients (50 deep pulmonary nodules), who underwent CT-guided localization with PBD injection, between November 2015 and May 2023 at our hospital. The nodules could be divided into four categories: (1) perifissural nodules, (2) paravertebral nodules, (3) paramediastinal nodules, and (4) deep parenchymal nodules, according to their location relative to the thoracic organs and the visceral pleura. Needle approach methods and needle pathway lengths were recorded. Clinical and radiological features, technical information, pathological results, and procedure-related complications were analyzed. Results: All 50 dyes were successfully identified by thoracoscopy and then resected without major complication. The mean nodule diameter and the nodular depth were 10.3 (range, 4.7-21.0) mm and 16.1 (range, 0.1-52.2) mm. The needle pathway length was 7.7 (range, 4.5-11.7) cm. The mean procedure time was 16 (range, 8-26) minutes. Asymptomatic pneumothorax developed in twenty-four patients (48.0%), and focal parenchymal hemorrhage occurred in four patients (8.0%) after localization. No patients required chest tube insertion or resuscitation. Conclusions: Strategic needle approach paths provide precise localization of deep thoracic pulmonary nodules with minimal complications. These methods offer a practical framework for improving thoracoscopic surgery in challenging deep thoracic cases.