No abstract

The common and important change of pulmonary hemodynamics is represented by increased or decreased pulmonary blood flow (PBF) and increased pulmonary vascular resistance (PVR). We made 3 hemodynamic models in 5 dogs, that is, increased and decreased PBF model and increased PVR model. CT perfusion scan was performed.Perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT), and maximal slope (MS) were analyzed. In normal state, blood flow was affected by gravity and dependent area showed higher BF, BV and lower MS, MTT than non-dependent area. First, decreased PBF model showed no significant change in BV and elongation of MTT. Secondly, increased PBF model showed slightly increased BV and decreased MTT. Thirdly, increased PVR model showed significant decrease of BF, BV, and MS and slight increase of MTT without statistical significance. However, it was noticeable that the distribution of MTT according to gravity in normal lung was completely reversed in increased PVR model. In conclusion, on the basis of our understanding of perfusion characteristic in normal state, we can detect and evaluate the abnormal regional hemodynamic change in lung.Predicting the change of pulmonary vascular resistance should be possible by thorough analysis of CT perfusion parameters.

No abstract

In order to study the treatment of aneurysms, the technique of making experimental aneurysms in laboratory animals must be established. In our study, to examine the feasibility of making experimental aneurysm and selective angiography on the common carotid artery in rabbits and to determine the size of experimental aneurysm after surgery, saccular aneurysms were fashioned on the right common carotid artery in 17 rabbits using a vein pouch technique. Selective angiography of the common carotid artery was performed immediately after surgery, and at 1 week, 4 weeks, and 8 weeks after surgery. Also, histological changes in the aneurysms were observed. In 16 rabbits with established successful experimental aneurysm, no differences were found in diet intake and behavior before and after surgery. The patency of the carotid artery was confirmed by selective angiography. The average size of the aneurysm immediately after surgery was similar to that of 1 week postoperatively in selective angiography, however it increased with time at 4weeks and 8 weeks. Histologically, infiltration of inflammatory cells and hemorrhage were found at the junction of the carotid artery and the vein pouch at 1 week, which disappeared at 4 weeks and 8 weeks. This study suggests experimental saccular aneurysm using the vein pouch technique might form aneurysms similar to that of the human in its properties such as increment of size, and selective angiography might be suitable for assessment of experimental aneurysm. Therefore, this animal model may be suitable for investigating new treatment methodologies for human aneurysms.