CTEPH. Comparison between planar and SPECT ventilation/perfusion scintigraphy in differential diagnosis of thromboembolic and non-thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease, which is the result of pulmonary emboli. Most emboli normally undergo resolution or leave minimal residua. For unknown reasons in CTEPH emboli do not resolve; the emboli follow an aberrant path of organization leaving endothelialized residua that obstruct pulmonary arteries and lead to right-heart failure. The aim of this study is the comparison between planar and SPECT V/Q, scintigraphy and which of them shows higher diagnostic value. The patients underwent planar V/Q scintiscans (tracer: 99mTc, 300.000 cts/frame, GPLE-collimator) and SPECT (UHRLE-collimator, 128-matrix; 3D-postfilter). Then I compared the scans with diagnosis made by cardiologists. I found that planar showed CTEPH in 9 and in four cases. Two cases of CTEPH were falsely diagnosed as PPH (sensitivity for PPH: 100 %, specifity: 80 %, pos. protective value: 57 %). Spect was right positive for CTEPH in 9, for PPH in 2 cases. 3 CTEPH cases were falsely diagnosed as PPH, 1 case as PPH with PE (sensitivity for PPH: 50 %, specifity: 73 %, pos. predictive value: 33 % neg. predictive value: 85 %). After execution of discriminance-analysis it had been proved, that planar technique is superior to SPECT. (author)