Agreement of Mediastinal Lymph Node Size Between Computed Tomography and Endobronchial Ultrasonography: A Study of 617 Patients.

Abstract

Endobronchial ultrasound (EBUS) is the preferred minimally invasive technique for the evaluation of intrathoracic lymphadenopathy. Enlarged lymph nodes on computed tomography (CT) are defined as those 1 cm or larger in short-axis diameter. Whether there is agreement between the measurements of lymph node size on CT and EBUS remains unknown. This was a retrospective analysis of prospectively collected data from patients who underwent EBUS-guided transbronchial needle aspiration (TBNA) for intrathoracic lymphadenopathy. The diameters of lymph nodes were measured in an axis perpendicular to the airway on both CT and EBUS. The correlation and agreement between the two measurements were analyzed. During the study period, 617 patients (mean age, 46.0 years [standard deviation, 15.2]), of whom 239 (38.7%) were women, underwent EBUS. A total of 1,153 lymph nodes were measured by CT and EBUS. Although there was a moderate correlation between the two modalities for lymph node size (Pearson correlation coefficient = 0.49, p < 0.001), the limits of agreement between CT and EBUS were wide (mean bias, 0.1; limits of agreement, -15.6 to 15.9 mm). The limits of agreement were wide for all categories of lymph nodes (benign vs malignant, distinct vs indistinct margin, and ≤2-cm vs >2-cm nodes). Despite a significant correlation between CT of the chest and EBUS for measuring the size of intrathoracic lymph nodes, the limits of agreement were fairly wide enough to be clinically acceptable for allowing the use of the two modalities interchangeably for this purpose.