Clinical Application Of CTA To Intracranial Aneurysms

PartⅠComparison of CTA and DSA in detecting and treatment of intracranial aneurysm.Objective:To investigate the value of CTA in detecting and treatment of intracranial aneurysm.Method:73 cases with suspected intracranial aneurysm underwent both CTA and DSA.The sensitivity,specificity and accuracy of CTA and DSA are assessed using surgical findings as gold standard.The dimensions of the aneurysm were measured independently with both techniques.The images of CTA and DSA were evaluated independently by two blinded neurosurgeons for characterization of aneurysm and compared with surgical findings.CTA and DSA were used to evaluate for the evaluation of aneurysms after surgical clipping and follow up.Results:A total of 61 aneurysms were detected at DSA in 56 cases.Sensitivity, specificity and accuracy per person for DSA were,respectively,96.55%,100%and 97.26%. A total of 62 aneurysms were detected at CTA in 56 cases.Sensitivity,specificity and accuracy per person for CTA were,respectively,96.55%,93.33%and 95.89%.There was no statistical difference in detecting ability between CTA and DSA(P＞0.05).There was significant correlation between the techniques(kappa=0.80).The difference between the techniques in quantitative dimensional measurement of aneurysm size was less than 1mm per aneurysm,did not reach statistical significance(t= 1.63,P＞0.05).CTA displayed the characterization of aneurysms better than DSA for both two observers(p＜0.05),correlated well with surgical findings.3 cases underwent DSA and 24 cases underwent CTA in 2 weeks after clip.1 patient was effectively depicted small aneurysm remnant by CTA, others were well clipped.No regrowth of clipped aneurysm or de novo aneurysm was found in 15 cases in 1 year follow up.Conclusions:There is no statistical difference in detecting ability between CTA and DSA.CTA display the characterization of aneurysms better than DSA,should be used as the first choice for evaluation of aneurysm pre and postoperative,treatment planning,and follow up.PartⅡApplication of simulating surgery on CTA for surgical clipping of intracranial aneurysmObjective:To investigate the value of simulating surgery on CTA for surgical clipping of intracranial aneurysm.Method:21 cases of anterior communicating artery aneurysm and 15 cases of internal carotid-posterior communicating artery aneurysm underwent the preoperative CTA examination and the simulating surgery on CTA.All of the 36 cases of aneurysm underwent the pterional approach surgery to clip aneurysm.The demonstrated from preoperative CTA were compared to intraoperative visualization.All cases underwent postoperative CTA for evaluation of the operation.Results:36 cases of aneurysm were clipped successfully.The demonstrated from preoperative CTA is basically consistent with intraoperative visualization.All aneurysms were well clipped depicted by postoperative CTA.Conclusions:Simulating surgery on CTA can help choosing best surgical approach, estimation influencing factors of surgery,reducing intraoperative injury and improving the quality of operation.PartⅢApplication of CTA in evaluation of cerebral vasospasm after subarachnoid hemorrhageObjective:To investigate the value of CTA in evaluation of cerebral vasospasm after subarachnoid hemorrhage. Method:18 cases with spontaneous subarachnoid hemorrhage underwent DSA between 3-10 days after the first onset.Both CTA and TCD were also undergone within 24 hours.The vessel diameter of internal carotid artery,middle cerebral artery,and anterior cerebral artery were measured on CTA and DSA images to evaluate the vessel stenosis. The blood flow velocities in these vessels were recorded by TCD.Vasospasm was graded into 4 grades depending on vessel stenosis and blood flow velocities.Sensitivity and Specificity of CTA and TCD for diagnosis of vasospasm in different grade were analyzed respectively,using DSA as the gold standard.Results:The overall sensitivity of CTA(85.7%) for diagnosis of vasospasm was a little higher than that of TCD(71.4%).For mild and moderate vasospasm,the sensitivity of CTA(71.4%and 80%) was a little lower than that of TCD(83.3%and 83.3).But the differences above did not reach statistical significance(P＞0.05).For severe vasospasm,the sensitivity of CTA(100%) is much higher than that of TCD(55.6),and there were significant differences between them(P＜0.05).The specificity of CTA and TCD were both very high(＞92%),differences between them did not reach statistical significance(P＞0.05).Conclusions:The sensitivity and specificity of CTA for diagnosis of vasospasm are very high,especially for severe vasospasm.CTA could be an altemative imaging technique to DSA or a supplementary test to TCD in the assessment of patients with cerebral vasospasm after aneurismal SAH.