Objective: The purpose of our study was to investigate clinician response and patient outcome associated with the radiologist's report of isolated subsegmental pulmonary emboli (ISSPE) or indeterminate or inconclusive results on MDCT for venous thromboembolism.
Materials and methods: All patients were examined using 8- or 16-MDCT. Reported findings on combined CT pulmonary angiography and CT venography of 1,435 consecutive patients were analyzed retrospectively. The charts of patients of interest with ISSPE or with indeterminate or inconclusive pulmonary embolism results were analyzed for clinician response and recurrent symptoms of venous thromboembolism in both treated and untreated patients during the following 3 months.
Results: We studied 207 patients of interest, and follow-up was available on 192 (92.8%) (67 ISSPEs, 125 inconclusive). Of the 192 patients, 25 (37%) of 67 patients with ISSPE and 108 (86%) of 125 patients with inconclusive results did not receive anticoagulation. Two patients with ISSPE and two patients with inconclusive results returned with new symptoms suggesting recurrent venous thromboembolism, but no venous thromboembolism was found. Thirteen (10%) of 133 untreated patients died without clinical evidence of recurrent venous thromboembolism. In 61 patients who received anticoagulation (42/67 [63%] ISSPE and 17/125 [14%] inconclusive), five patients returned with venous thromboembolism symptoms. None had recurrent emboli. Two (3%) of 61 patients who received anticoagulation died of other diseases.
Conclusion: Patients with ISSPE more commonly received anticoagulation than not. In the patients who did not receive anticoagulation, no recurrent pulmonary embolism was identified on follow-up. In most patients with inconclusive findings on CT pulmonary angiography, clinicians chose to withhold anticoagulation without additional imaging workup. No adverse effects of this clinical decision were uncovered.