| [Objective] To evaluate the diagnostic value and limitation ofpulmonary embolism with three-dimensional dynamic contrast-enhanced magnetic resonance pulmonary angiography. PE appearances on 3D DCE MRPA were summarized by the animal experiment and clinical application studies of 3D DCE MRPA.[Materials and Methods]Part I: Animal experimental study on 3D DCE MRPA: (1) 8 rabbitsfirst were performed 3D DCE MRPA with Gd-DTPA contrast medium at the dosage of 0.2mmol/kg and 0.3mmol/kg respectively. (2) These rabbits underwent digital subtract angiography and embolism models were done after 3D DCE MRPA. A catheter was introducing to right atria through external jugular vein by operation. After pulmonary artery angiography was done successfully, pulmonary arteryies were embolized with strip gelatin sponges of about 1-2 mm in diameter. When filling defect or complete obstruction of pulmonary arteries was found under DSA, The models of PE were demonstrated successfully. (3) Model rabbits were again performed 3D DCE MRPA. (4) Subsequently, these model rabbits were anatomized. The appearances of lung were observed to find the areas of infarction. Later, pulmonary arteries were opened with shears along direction of pulmonary6artery. Emboli were searched and tagged. Pathologic sliced were done at the same time. (5) A comprehensive analyse was done among pre-post of pulmonary embolism on 3D DCE MRPA, DSA and pathology in the end.Part II: Clinical application study on 3D DCE MRPA: 3D DCE MRPA was performed in 38 patients suspected PE with Gd-GDPA contrast medium at the dosage of 0.2mmol/kg and at the flow rate of 2m1/s. 3D FFE sequence was performed on a 1.5 tesla MR system made in TOSHIBA. Among them, 8 patients underwent digital subtract angiography, 15 CE MRA images including pulmonary artery were acted as the negative contrast group. These patients were suspected of lesions in the subclavicular artery and aorta artery.All these data were analyzed with SPSS statistical analysis system: the measured data were analyzed with paired-samples T test and the count data were analyzed with 2 independent samples nonparametric test.[Results]Part I : Animal experimental study on 3D DCE MRPA: 1 rabbit diedwhen the embolism modle was done. 7 rabbit models of pulmonary emboliwere made successfully. All data of the quilt of image, the values of the diameters of pulmonary artery, SNR, CNR were no significant differences in . statistics (p>0.05). (1) In all imagings on 3D DCE MRPA, pulmonary vessel status can be visualized effectively: pulmonary arteries of both diaphragm lobes were displayed best, their satisfactory rate of visualization were 100%, right and left pulmonary arteries were second, their satisfactory rate of show were 85.7%, main pulmoanary artery was 42.9%, pulmonary arteries of heart lobe and tip lobe were displayed poorly, right heart lobe and tip lobe were 42.9%, left tip lobe was only 14.3%. (2) The direct sign of PE on 3D DCE MRPA and DSA were as follows: cut-off of pulmonary artery,constriction of pulmonary artery, filling defect or local stenosis of\pulmonary artery; the indirect sign of PE were as follows: the abnormal signals and pour defects were found in the lung field of PE, the dilatation of the nub of obstructed pulmonary artery. (3) 90 branches of pulmonary arteries were examined under naked eyes and microscope. 16 emboli were found. 14 of 16 located in the level of lobe artery, 2 of 16 located in the level of segmental artery. Pathology dessection was as the reference gold standard, the sensitivity and specificity of 3D DCE MRPA were 81.25%, 98.65% respectively; the sensitivity and specificity of DSA were 75%, 98.65% respectively.Part II: Clinical study on 3D DCE MRPA: (1) the quality of 35 3 D DCE MRPA images from 38 patients suspected pulmonary embolism was good. The reveal rate of I - II pulmonary arteries were 100%,the reveal rate of lobar pulmonary arteries were 92.1%, the reveal rate of segmental pulmonary arteries were 44.7% , the reveal rate of sub-segmenta...
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