Value Of Multislice CT Pulmonary Arteriography In The Diagnosis Of Pulmonary Embolism

Objective: To compare the frequency of embolus of well-visualized pulmonary arteries according to anatomic level by using different reconstruction slice thickness with multislice CT pulmonary arteriography and analyze its diagnostic value. Materials and Methods: The CT scan images with slice thickness of 2.5mm(groupl) and 1.25mm(group2) were reconstructed in 38 patients with pulmonary embolism after contrast enhanced spiral CT angiograms. Two thoracic radiologists independently reviewed examination findings to determine if each lobar, segmental, subsegmental, fifth artery was well-visualized for presence of pulmonary embolism, x 2 tests were performed. For well-visualized arteries,the presence and/or absence of pulmonary embolism was recorded and k statistic was determined. Results: Readerl scored 98% and 99% of lobar arteries(p>0.05, x 2 test); 88% and 95% of segmental arteries(p<0.001, x 2 test); 29% and 47% of subsegmental arteries (p<0.001, x 2 test); 3% and 9% of fifth arteries (p<0.001, x 2 test) as well visualized using techniques 1 and 2, respectively. Reader 2 scored 99% and 99% of lobar arteries(p>0.05, x 2 test); 85% and 92% of segmental arteries(p<0.001, x 2 test); 28% and 44% of subsegmental arteries (p<0.001, x 2 test); 3% and 8% of fifth arteries (p<0.001, x 2 test) as well visualized using techniques land 2, respectively. The percentages of the presence with pulmonary thromboemboli in the well-visualized arteries were 38% and 40% of lobar arteries (p>0.05, x2 test); 17% and 21% of segmental arteries(p<0.05, x 2 test); 1.7% and 4.6% of subsegmental arteries(p<0.05, x 2 test) using techniques 1 and 2 respectively by readerl; and 35% and 37% of lobar arteries (p>0.05, x 2 test); 16% and 21% of segmental arteries(p<0.05, x 2 test); 1.6% and 4.2% of subsegmental arteries(p<0.05, x 2 test) by reader 2. The k values between two readers were 0.70 at lobar level; 0.69 at segmental level; 0.63 at subsegmental level in group 1; and 0.78; 0.86; 0.72 in group 2 respectively. Conclusion: Multislice CT pulmonary arteriography with 1.25mm reconstructed slice thickness significantly improves visualization of pulmonary thromboemboli at segmental and subsegmental arteries and interobserver agreement in detection of pulmonary embolism.