A comparison of ventilation/perfusion SPECT and CTPA for diagnosis of pulmonary embolism

Objectives To assess the diagnostic accuracy between ventilation/perfusion SPECT and CTPA for pulmonary embolism (PE).

Methods A prospective multicenter study,111 patients who were clinically confirmed or suspected of acute PE. Patients underwent one-day method V/Q scan(including SPECT and Planar imaging) within 3 days before and after the CTPA.Evaluation criteria of SPECT used The EANM guidelines for ventilation/perfusion scintigraphy2009.RM-PIOPED for Planer imaging. According to the direct and indirect signs of PE.Following up with 6 months.By respiratory physicians,radiologists,nuclear medicine physicians together determine a final comprehensive diagnosis.The differences among the diagnostic tests were tested for significance using chi-square test.The receiver operator characteristic(ROC)curve was drawn according to the results of the three diagnostic test.The area under ROC curve were calculated and compared.p<0.05 were considered statistically significant.

Results The 111 patients, which confirmed the PE 80 cases, excluding PE 31 cases. V/Q SPECT, planar imaging, CTPA diagnostic sensitivity/specificity/accuracy respectively, 85.9%/ 93.5%/ 88.1%, 75.7%/ 92.9%/ 81.4%, 85.5%/ 90.0%/ 86.8%. The ROC curve analysis, the AUC value of V/Q SPECT, planar and CTPA were 0.898, 0.838, 0.877, respectively. 95% Confidence intervals [CI] were 0.831 to 0.966, 0.759 to 0.917, 0.801 to 0.954, respectively. The area of the fitted smooth ROC curve is in statistical significant (p<0.05), compared with the area under the reference line. The area under ROC curve of the V/Q SPECT was the maximum.

Conclusions Comprehensive analysis indicates the SPECT V/Q imaging is superior to V/Q planar scan in aspect of PE, as well as CTPA; the fewest cases of non-diagnostic results is SPECT V/Q imaging among the three diagnostic tests.

Research Support Fund by clinical application research of Beijing Science & Technology Program