| ObjectivesThe objectives of this study were to discuss and find out the best scanning technique formulti-slice comupted tomography(MSCT), to evaluate the application significance of MSCT onthe diagnosis of aortic dissection(AD), to make a study on the correlation between the size ofintimal tear and the level of blood pressure, to analyze the relationship between the types of ADand hypertension, to focus on the comparison of different vascular invasions of both renalarteries and discuss the possible causes.Methods and materials35 patients checked up by MSCTA and diagnosed as AD in the First Affiliated Hospital ofShantou University Medical College during Dec.2006 to Jun.2009 were studied. To illustrate thediagnostic significance of MSCTA for AD and make comparison among the observational resultsfrom several reconstruction techniques such as MPR, CPR, MIP with MIP Thin and VR with VRThin. To figure out the main factor which may affect the observation of the intimal tear, these 35patients were then grouped based on three different scenarios, for instance, whether there wasthrombus in false lumen and the observational results of the intimal flap as well as the intimaltear, and then analyze the relationship among these three scenarios. In addition,a study on thecorrelation between the size of proximal intimal tear and the level of blood pressure was carriedout, and then following by the analysis on the relationship between the types of AD andhypertension. Finally, the study focused on different vascular invasion of both renal arteries,and discuss the possible causes.Results1. 35 patients all obtained satisfying images after the examination of computed tomographyangiography (CTA), which satisfies the diagnostic request based on cross-sectional imagesand the combination of several reconstruction techniques. 2. There is no statistical significance between the difference of the suffering rate ofhypertension in the patients with stanford type A aortic dissection or type B dissection.3. The observational results show high consistency of the size of true lumen and false lumen bymeasuring the area or the diameter (k=0.720, p=0.002).4. 28 patients whose proximal intimal tear were demonstrated clearly were then divided intotwo groups: firstly, the intensity of the true lumen was higher than the false lumen obviouslyin 17 patients,secondly, approximate intensity in the true lumen and false lumen was foundin 11 patients. Between the two groups, the average size of the proximal intimal tear in thefirst 17 patients group was smaller than the 11 patients group.5. No discrepancy was found in the demonstrated results of true lumen, false lumen, intimaltear and intimial flap by applying various reconstruction techniques, such as MPR, CPR, MIPwith MIP Thin, VR with VR Thin.6. The study shows a close relationship between the demonstration of the intimal flap and theformation of thrombus in false lumen(rs=0.573, p=0.001) ,and a close relationship betweenthe demonstration of the proximal intimal tear and the intimal flap (rs=0.739, p=0.000). Italso shows a relationship between the demonstration of proximal intimal tear and theformation of thrombus in false lumen (rs=0.372, p=0.041).7. The study shows the size of proximal intimal tear is irrelevant to systolic pressure (rs=-0.010,P=0.961), and the size of proximal intimal tear is irrelevant to diastolic pressure (rs=-0.070,P =0.746). It also shows no correlation between the size of proximal intimal tear and theclassification of blood pressure (rs =-0.019, p =0.930).8. The origination from the true lumen in the right renal artery is more common than which inthe left renal artery. While the origination from the false lumen in the left renal artery is morecommon than which in the right renal artery. There is no distinct probability in theorigination from true lume and false lumen simultaneously in both renal arteries.9. There is a significant difference in the angle of both renal arteries, the angle of right renalartery is smaller than the left one.10. All the invasive renal arteries are grouped by the different origination. However, there is nostatistical significance in comparing the angle of the artery from different groups. ConclusionMSCTA has a very important application meaning in the diagnosis of AD. The needs of thediagnosis on AD in actual clinical operation can be satisfied by applying reconstructiontechniques such as MPR, CPR, MIP with MIP Thin, VR with VR Thin to the obtained data. Theformation of the thrombus in false lumen is one of the main causes which result in the uncleardemonstration of the intimal tear; the size of proximal intimal tear is irrelevant to the level ofblood pressure, and there is no statistical significance between the difference of the suffering rateof hypertension in the patients with differente types of AD; there is a significant difference in theorigination of both renal arteries, which is irrelevant to the angle of them. |
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