Application Of Dual Energy CT Lung Perfusion Imaging In Acute Pulmonary Embolism

Part I Application value of dual energy CT imaging in diagnosing pulmonary embolismObjective To evaluate the value of dual source dual energy CT pulmonary angiography combined with perfusion imaging in patients with pulmonary embolism.Methods 165 patients with clinical suspected pulmonary embolism underwent dual energy CT angiography using the software algorithm of dual energy lung perfusion(Duel Energy Lung PBV) iodine distribution.Two experienced radiologists to diagnose consitent results on CTPA taken as reference standard and diagnosed pulmonary embolism enrolled in this study.The diagnostic performance of the software for the detection of pulmonary embolism was randomly assessed by consensus reading of other two blinded radiologists again. The position and the number of perfusion defects and(or) hypoperfusion were recorded on segmental basis. the correct diagnosis index was used to calculate diagnostic performance with Lung PBV, calculate the sensitivity value,specificity value,positive predictive value and negative predictive value.Results 70 patients were diagnosed with PE in CTPA, Lung PBV correctly diagnosed 65. With Lung PBV, the diagnosis performance of pulmonary embolism sensitivity, specificity,positive predictive value, negative predictive value was 92.9%、70.6%、72.2%、92.3%,respecrively; the correct diagnosis index with Lung PBV PE was 80.65%.Based on lobes,segments and subsegments the diagnostic accuracy was 73.0%,72.3% and 82.0%,respectlvely;pulmonary arteries were occlusive in lobes,segments and subsegments associated with perfusion defects;non-occlusive in lobes,segments and subsegments associated with hypoperfusion.Conclusion Lung blood abnormalities with PE could be accurately detect using dual-energy CT lung PBV perfusion imaging But associated with the degree and postion of pulmonary embolism,has the highest diagnostic accuracy of subsegmental pulmonary embolism. Part II Perfusion defect score combinated clinical and morphological parameters of right ventricular and blood gas with dual energy CT for assessment of severity of acute pulmonary embolismObjective To prospectively analyse the correlation between perfusion defect score(P-score) and CT pulmonary angiographic obstruction(CTPAOI) index,the correlation between right ventricular morphological parameters,arterial blood gas and the two kinds of scores in assessment of APE severity.Methods Patients with severe cardiopulmonary disease, poor quality of the image and incomplete clinical data was ruled out,taken routine computed tomography pulmonary angiography as the digonstic criteria,57 patients were diagnosed with APE and complete clinical data included in this study.According to the Qanadli and Zhou methods to calculated the P-score and CTPAOI,evaluated the correlation between the CTPAOI score and P-score,assessed the correlation between P-score and RV/LV diameter ratio was measured on reconstructed four-chamber view and blood gas parameters;the 57 patients divided into RV/LV>1(n=18)and RV/LV<1(n=39)according to the clinical group criterion,evaluated the right ventricular morphological parameters and differences between the two scors. Statistical analysis used SPSS 17.0 statistical package.Spearman rank coefficient was used to investigate correlation between P-score, CTPAOI and right ventricular(RV) to left ventricular(LV) diameter,(RV/LV).Performed Spearman rank coefficient to investigate the correlation between P-score and arterial blood gas. Performed the Mann-Whitney U test to evaluate differences in CTPAOI,P-score,main pulmonary artery diameter(m PAd),superior vena cava diameter(SVC d) and azygos vein diameter(AVd) between RV/LV>1 and RV/LV<1 groups.The χ2 test was used to assess morphologic signs of right ventricular strain on CTPA between the two groups.Results The P-score had a strong positive correlation with CTPAOI score(r=0.754,P<0.001)and slight to moderate negative correlation with Pa O2,Pa CO2,Sa O2(r=-0.289,-0.267and-0.305,respectively);both scores had a strong positive correlation with RV/LV diameter ratio as measured on reconstructed four-chamber view(r=0.539,P < 0.00;r=0.421,P=0.001);the differences of right ventricular morphological parameters were statistically significant between RV/LV>1and RV/LV<1 groups(all P<0.05).Conclusion P-score had a strong positive correlation with CTPAOI score and blood gas parameters,considering the P-score,CTPAOI score,right ventricular morphological parameters and blood gas parameters together could helpfully precise the assessment of APE severity.