Comparison of results of computed tomography and radiography with histopathologic findings in tracheobronchial lymph nodes in dogs with primary lung tumors: 14 cases (1999-2002).

OBJECTIVE: To compare results of computed tomography (CT) and radiography with histopathologic findings in tracheobronchial lymph nodes (TBLNs) in dogs with primary lung tumors.
DESIGN: Retrospective case series. ANIMALS: 14 client-owned dogs. PROCEDURES: Criteria for inclusion were diagnosis of primary lung tumor, use of thoracic radiography and CT, and histologic confirmation of TBLN status. Medical records were reviewed for signalment; history; and physical examination, clinicopathologic, radiographic, CT, surgical, and histopathologic findings.
RESULTS: Tracheobronchial lymphadenopathy was not identified via radiography in any dogs. Tracheobronchial lymphadenopathy was diagnosed in 5 dogs via CT. Six dogs had histologic confirmation of metastasis to TBLNs. Radiographic diagnosis yielded 6 false-negative and no false-positive results for tracheobronchial lymphadenopathy. Computed tomography yielded 1 false-negative and no false-positive results. Sensitivity of CT for correctly assessing TBLN status was 83%, and specificity was 100%. Positive predictive value was 100%, and negative predictive value was 89%. Dogs with lymphadenopathy via CT, histologic confirmation of TBLN metastasis, or primary tumors with a histologic grade > 1 had significantly shorter survival times than their counterparts. CONCLUSIONS AND CLINICAL RELEVANCE: Results of CT evaluation of TBLN status were in agreement with histopathologic findings and more accurate than use of thoracic radiography for evaluating TBLNs in dogs with primary lung tumors. Computed tomography imaging should be considered as part of the staging process to more accurately assess the TBLNs in dogs with primary lung tumors.