CTPA Versus V/Q Scan In Diagnosing Pulmonary Embolism

Objective: To assess the clinical value of computed tomography pulmonary angiography (CTPA) and ventilation-perfusion (V/Q) radionuclide lung scanning in the diagnosis of pulmonary embolism (PE). Materials methods: One hundred seventeen patients who were clinically suspected of having pulmonary embolism underwent CT angiography and ventilation-perfusion (V/Q) radionuclide lung scanning. Final clinical diagnosis was pulmonary embolism in 45 (37.9%) and no pulmonary embolism in 72 (62.0%) .According to an identical standard, two group experienced observers independently assessed examination findings. Performed x ~2 tests to compare the differences in the diagnostic accuracy between CTPA and V/Q scanning. Using the kappa statistic assessed the interobserver agreement. Result: The sensitivity, specificity, coincidence, positive predictive value, negative predictive value and rate of indeterminate findings of the first group observer for CTPAand V/Q were respectively 93.3% versus 75.6% (P<0.05, x~2 test), 95.8% versus 81.9%(P<0. 05, x ~2 test), 94.8% versus 79.5%(P<0. 01, x~2 test), 97.7% versus 81%, 95.8% versus 92.2%, 1.7% versus 9.4% (P<0. 05, x~2 test) . The sensitivity, specificity, coincidence, positive predictive value, negative predictive value and rate of indeterminate findings of the first group observer for CTPA and V/Q scanning were respectively 93.3% versus 75.5% (P<0. 05, x~2 test) , 94.4% versus 80.6% (P<0. 05, x~2 test) , 94.0% versus 78.6% (P <0. 05, x~2 test), 97.7% versus 81%, 95.7% versus 95.1%, 2.6% versus 13.6% (P<0.05, x~2 test). Interobserver agreement was excellent for helical CT angiography (?=0.91) and moderate for ventilation-perfusion radionuclide lung scanning (?=0.69). Conclusion: CTPA is more accurate in the diagnostic procedute of PE compareing with the V/Q scanning . CTPA could replace V/Q scanning as the initial test for patients who are clinically suspected of having pulmonary embolism.