Evaluation Significance Of The Computed Tomography Angiography And Digital Subtraction Angiography In Diagnosis And Treatment Of Type B Aortic Dissection

Objectives Acute aortic dissection is the most common catastrophic event affectingthe aorta.Aortic dissection (AD) involves a tear in the intima of the aorta, allowingblood to flow within layers of the media. This creates a false lumen for blood flow in theintramural space, which may compress the true lumen or extend into branch arteries,inducing malperfusion. Modern imaging technologies, such as computed tomographyangiography(CTA) and digital subtraction angiography(DSA) are widely used forpretreatment evaluation of aortic dissection (AD),but the consistency of the twomodalities are unclear. The objective of this study is to compare the computedtomography angiography(CTA) with digital subtraction angiography(DSA) in diagnosisof aortic dissection and evaluate the value in thoratic endovascular aorticrepair(TEVAR).Methods Between June2009and December2010,40patients with acute type Baortic dissection,3females and37males, age range36～81yrs, mean age53.67±9.21yrs,who were examined by both CTA and DSA, were analyzed respectively. The CTAhas several technical features, Maximum intensity projection (MIP), multiple planarreformation (MPR), volume rendering (VR), curved multiplanar reconstruction(CPR),shaded surface display (SSD),and so on. Imaging can clearly show the entire aorticblood vessels. DSA is regarded as the gold standard for diagnosis of aorticdissection.The following aspects were compared between CTA and DSA including intimal tear, the number of tear, the diameter of the aortic close to the left subclavianartery(LSA), true and false lumen area, the distance from proximal edge of the tear tothe LSA, thrombosis in the false lumen, calcified plaque, origin of artery branches. Ourstudy group included34patients with acute type B aortic dissection who underwentTEVAR.Endoleaks were appraised after TEVAR.Results Forty patients underwent CTA and DSA. TEVAR were performed in34cases.No statistical difference was found in the number of tearsand the distance fromproximal edge of the tear to LSA and aortic diameter between CTA and DSA. Left iliacartery (LIA) and right iliac artery (RIA) are involved in the dissection were discoveredin16(16/40,40.0%),6(6/37,15.0%) cases by CTA and15(15/40,37.5%),6(6/37,15.0%)cases by DSA. There was significant difference in identifying LIA and RIA involved inthe dissection between CTA and DSA (P<0.05). Thrombosis in the false lumen andcalcified plaque was found by CTA and not by DSA. Type I endoleak was detected in11(11/34,32.35%) cases.Conclusions The two methods(CTA,DSA) were coincident with each others. DSAhas the benefit in real-time evaluation of the diseased aorta and guide the placement ofstent-graft. CTA has the significant value in pre-operative decision-making andfollow-up post-operatively.