The effect of imaging modality on patient management in the evaluation of pulmonary thromboembolism

A retrospective medical record review was performed to study the difference s in clinical risk profiles and the relationships between test results vers us management for suspected pulmonary thromboembolism (TE) in patients unde rgoing either radionuclide ventilation perfusion (V/Q) scans or pulmonary c omputed tomographic angiography (CTA), as the initial test. Data of 138 con secutive V/Q patients were compared with that of 149 consecutive CTA patien ts during equivalent 6-month intervals before and after the introduction of CTA. Information on risk factors, signs and symptoms, all diagnostic test results, and the relationships between the test results and ultimate physic ian management were collected and analyzed. V/Q results predicted physician management in all patients with high probability scans and 91% with normal to low probability scans. There were 35 patients with indeterminate V/Q sc ans-43% of these patients were managed without any other diagnostic test. C TA results predicted management in all patients with positive studies and 9 9% of patients with negative studies. In contrast to the V/Q cohort, only s even CTA studies were inconclusive-additional diagnostic tests determined m anagement in all but one case. Compared with V/Q, CTA has fewer indetermina te results, is more directly reflective of management, and reduces the numb er of patients managed with inconclusive data.