Multimodal assessment of the magnitude of necrosis in the tracheobronchial tree after laser therapy

The use of lasers for treating cancerous lesions of the tracheobronchial tree has gained world-wide interest. As the prevalence of superficial cancer increases, lasers have been increasingly used to ablate superficial lesions. The extent of the effects of laser ablation on bronchial tissue is still unknown, and there may be a risk of bronchial wall perforation. In order to explore the magnitude of necrosis after laser treatment in the tracheobronchial tree, we investigated the microscopic appearance, histologic changes, and images of damaged mucosal lesions taken by optical coherence tomography (OCT). Endoscopic OCT is complementary to endobronchial ultrasonography (EBUS), which has a spatial resolution of about 100 μm and a penetration depth of about a few centimeters. Multimodal investigation using both OCT and EBUS is a powerful in vivo tool for evaluating the efficacy of laser therapy in the tracheobronchial tree. In this study, we performed an ex vivo feasibility test that provided an adequate laser dose without cartilage injury. Injury extent was evaluated using OCT, EBUS, and histologic images.

► The depth of tracheal necrosis was imaged using OCT and EBUS with different laser dose.
► Ten to 15 J/cm2 (for 1 s) showed a higher risk for tracheal perforation.
► OCT showed higher intracartilaginous lesion detection rates (90% vs. 60%) than EBUS.
► EBUS showed higher extracartilaginous lesion detection rates (80% vs. 50%) than OCT.