PURPOSE: Our clinical experience suggested that there maybe be a discrepancy between the sizes of pathologic lymph nodes measured by Computed Tomography (CT) scan when compared to direct visualization with Endobronchial Ultrasound (EBUS). Sub-centimeter lymph nodes measured on CT scans are not routinely biopsied and this practice could have important diagnostic, treatment and prognostic consequences.
METHODS: We conducted a prospective study on twenty (20) patients at our institution that examined the accuracy between the sizes of pathologic and non-pathologic lymph nodes sampled by EBUS compared to its estimated size on CT scan.
RESULTS: Five (5) out of twenty (20) or 25% of these patients had a pre-existing malignancy. Thirty-seven lymph nodes were sampled by EBUS and all samples were diagnostic. Thirteen (13) out of thirty-seven (37) or 35.14% of these nodes were positive for malignancy. CT scan underestimated the size of pathologic lymph nodes when compared to EBUS. Overall, the mean size of both pathologic and non-pathologic lymph nodes visualized with EBUS was larger than was measured on CT scan. The mean nodal size on CT scan was 16.15 x 12.15 mm versus 19.84 x 16.72 mm on EBUS (p-values 0.001 and 0.005 for upper- and lower-limit dimensions respectively).
CONCLUSION: Pathologic and non-pathologic lymph nodes seen on direct visualization with EBUS had significantly larger dimension than when measured with CT scan and this was independent of the lymph node station. In addition, EBUS led to the discovery and eventual biopsy of pathologic lymph nodes that were missed on CT scan.
CLINICAL IMPLICATIONS: This is an important observation since it may allow timely diagnosis and staging of a new hematologic or solid malignancy, identification of recurrent or metastatic malignancy and may provides a less invasive method of diagnosing pulmonary diseases such as pulmonary sarcoidosis.
DISCLOSURE: Timothy Udoji, No Financial Disclosure Information; No Product/Research Disclosure Information