Radial probe endobronchial ultrasound: factors influencing visualization yield of peripheral pulmonary lesions

Endobronchial ultrasound (EBUS) has improved the diagnostic yield of transbronchial biopsy of peripheral pulmonary lesions (PPL). While EBUS diagnostic yield has been the focus of the majority of publications, few have investigated factors associated with EBUS visualization yield. This study evaluated the factors predicting visibility of PPL using EBUS-guided bronchoscopy.

We performed a retrospective analysis of 196 consecutive patients who underwent investigation with radial EBUS. Size and distance of the lesion from the hilum and pleura measured on computed tomography scans were correlated with malignancy status, gender and EBUS visualization yields. Final diagnosis was obtained from pathology.

A definitive diagnosis was established for 109 PPL (56%) using radial EBUS. Visualized lesion by EBUS probe had a higher diagnostic yield (65%) than EBUS-invisible lesions (20%; P = 0.0001). In multivariate analysis, lesion size, final diagnosis and distance from hilum to lesion were all found to significantly affect EBUS visualization yield. Lesions of ≥ 20 mm had a significantly greater visualization yield (85%) than lesions of <20 mm (63%; P = 0.0022). Malignant lesions had a higher visualization rate (85%) than benign lesions (66%; P value = 0.0025). Distance of hilum ≤ 50 mm to PPL was found to have a significantly higher visualization yield (91%) than lesions located >50 mm from the hilum. (66%; P = 0.0001).

Lesion size, malignancy status and distance from hilum to lesion are significant predictors of EBUS visualization yield. Clinicians should review these factors in patients to guide choice of optimal investigation and diagnosis of PPL.