Study Of Detection Ability Of Peripheral Pulmonary Arteries Displayed With 8-slice Spiral CTA

Purpose: To analyze the detection ability of peripheral pulmonary arteries with 8-sliceCTA and the influencial factor.Methods: Peripheral pulmonary arteries were analyzed on contrast material-enhanced spiral CT angiograms in 40 patients devoid of pleuroparenchymal disease who underwent scanning with multi-slice row CT(collimation,8 X 1.25mm;pitch,1.35;scanning time,0.5secend). Two series of scans were systematically generated from each date set,1.25mm-thick sections 0.625mm-intervals(group 1) and 2.5mm-thick sections , 1.25mm-intervals(group 2),leading to the analysis of 800 segmental(20 arteries per patient), 1,600 subsegmental (40 arteries per patient), 3,200 fifth-order (80 arteries per patient), and 6,400 sixth-order (160 arteries per patient) pulmonary arteries in each group.Consensus interpretation of the CT images was performed by two radiologists who experienced in the reading of helical CT angiograms of the pulmonary circulation.The analyzable pulmonary arteries were recorded and the statistical analysis was performed.Results: The percentage of analyzable segmental arteries was same identical both in group 1 and in group 2(99.38%[795/800]); For subsegmental pulmonary arteries, the resolution was 94.44%(1511/1600) in group 1 and 83.06%(1329/1600) in group 2, there was a significant difference between them( p<0.01); For fifth-order pulmonary arteries, the resolution was 70.59% (2259/3200) in group 1 and 44.78% (1433/3200) in group 2,there was a significant difference between them( p<0.01); For sixth-order pulmonary arteries, the resolution was 31.81% (2036/6400)in group 1 and 14.29%( 915/6400)in group 2,there was a significant difference between them( p<0.01).Conclution : (1) Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections enables accurate analysis of peripheral pulmonary arteries down to the fifth order on spiral CT angiograms. (2) The resolution of peripheralpulmonary arteries was better in reconstructed images of 1.25-mm-thick sections than that of 2.5-mm-thick sections.The reconstructed slice-thick of images was an important factor that influences the resolution of peripheral pulmonary arteries.