Aim: Comparative analysis about helical CT (ThC) vs ventilation-perfusion pulmonary scintigraphy (V/P Sc) diagnosis effectiveness, as a first diagnosis technique in patients with high clinical suspicion of pulmonary thromboembolism (PT).
Materials and methods: Prospective study of 30 patients with high clinical suspicion and high Dimer-D levels (> 250 microg/l). The diagnosis was defined as anticoagulant therapeutic prescription and posterior clinical evolution. V/P Sc were performed to each patient within the next 48 h (an average of 14.8 h) after TCh, without anticoagulant treatment. We classified the scintigrams according to the PIOPED criteria and hTC images as positive, negative and indeterminated.
Results: In sixteen patients final diagnosis was PT: in 9 both techniques were positive; in 5 scintigraphy was positive with normal hTC and in 1, hTC was normal with negative scintigraphy. The last case was an indeterminated hTC with negative scintigraphy. In fourteen patients, final diagnosis was non-PT: in 6 both techniques were negative; in 7 scintigraphy was negative with positive hTC and in 1, both results were indeterminated. The sensitivity, specificity, positive predictive value, negative predictive value and efficiency were respectively 87.5, 100, 100, 87.5 and 93 % for V/P Sc and 62, 50, 58.8, 53.8 and 53 % for TCh.
Conclusion: V/P Sc has better PT diagnosis reliability. It is recommended to do V/P Sc in all patients with high clinical suspicion of PT.