The Experimental Study Of Sixteen Slice Computed Tomographic Pulmonary Angiography And Pulmonary Perfusion/Ventilation Imaging In Pulmonary Embolism

Objective:To evaluate the diagnostic value and limitation of pulmonary embolism with the experimental study of 16-slice computed tomographic pulmonary angiography and pulmonary perfusion-ventilation imaging PE appearances on CTPA were summarized by the animal experiment studies of CTPA.Materials and Methods:1.CTPA inspections were made on 22 healthy mongrel dogs, with Angiogtafin as constrast medium to observe CTPA's displaying of pulmonary arteries. 2. DSA inspection and preparation of pulmonary embolism artery models were made after CTPA inspection: send the catheter into main pulmonary artery through femoral vein; embolize pulmonary arteries using gelatin sponge and chorda serica chirurgicalis as embolism after successful arteriography of pulmonary arteries; make arteriography of pulmonary arteries and the filling defection and desected transformation means the successful making of models. 3. CTPA and ECT inspections were made on model dog respectively. 4. Pathoanatomy and observation of appearance of lung were made after the execution of dogs to make pathological section of embolized positions promoted by DSA. 5. Aggregate analysis of DSA, CTPA, ECT V-P images before and after embolism were made to evaluate the sensibility and specificity of CTPA and ECT V-P in diagnosis of PE with the standard of DSA.Results:1 2 dogs died when the embolism modle was done.20 dogs'pulmonary embolism models were successfully prepared. All the CTPA images displayedthe pneumoangiogram clearly: the satisfactory rate of images is 100%; the displaying rate of pulmonary artery above lobe is 100%; the displaying rate of some dogs'anterior and accessory lobes is a little lower than 50%; the satisfactory rates of images of anterior accessory and posterior lobes are 20%, 25% and 55%; 2 dogs posterior lobes pulmonary artery has 6 branching visualization and low satisfactory rate.2 The direct sign of pulmonary embolism DSA and CTPA is pulmonary artery's cutoff, filling defection or local stenosis within pulmonary artery. The indirect sign of pulmonary embolism DSA and CTPA is the abnormal signal in the lung field of embolism segment, filling defection, widening of blood vessel in amputation stump of pulmonary artery.3 308 pulmonary arteries above sub-segments were found in the lung field along 20 dogs'embolism. 99 embolism arteries were diagnosed by DSA, 58 segmental arteries and 41 sub-segmental arteries. 83 pulmonary arteries were diagnosed by CTPA, 9 were missed diagnosed and 25 were misdiagnosed. 112 S-T segmental pulmonary arteries embolism were diagnosed by ECT V-P, 11 arteries were missed diagnosed and 24 artery branches were misdiagnosed. The sensibilities of HCTPA and ECT V-P in diagnosis of pulmonary artery embolism are 74.7% and 88.9%. The specificities of HCTPA and ECT V-P in diagnosis of pulmonary artery embolism are 95.7% and 88.5%. The sensibility and specificity of CTPA in diagnosis of pulmonary artery embolism above segments are 86.2% and 98.4%. The statistic analysis showed that CTPA and DSA did not have statistic difference in diagnosis of pulmonary artery embolism above segments, with the accuracy as 58.5%.Conclusions:1 HCTPA is an inspection technique of bellows blood vessel with no hurt and high hypersensitivity, which can clearly display sub-segmental pulmonary arteries.2 HCTPA is safe and effective in diagnosis of pulmonary artery embolism, which can clearly display the embolized pulmonary artery above segments. It has favourable concordance compared with DSA and can replace DSA in the clinical diagnosis of PE in some extent, whose accuracy in the concordance of sub-segmental artery infarction is raised but still not satisfactory.3 HCTPA has higher sensibility and specificity in diagnosis of PE compared with ECT V-P. However, radioisotope scanning has its unique advantages. The accuracy of PE diagnosis can be enhanced when they were combined.