The Research Of 16-Slice Spiral CT Angiography In The Diagnosis Of Cerebrovascular Diseases

Purpose: To evaluate the feasibility and significance of 16-slice spiral CT angiography in the diagnosis of cerebrovascular diseases.Materials and Methods: 124 patients suspected cerebrovascular diseases were chosen to undergo CTA with 16-slice spiral CT. According to the different methods of determining the delay time, the patients were randomly divided into group land group 2. Patients in Group 1, 63 cases, were scanned with fixed delay time, and those in Group 2, 61 cases, with delay time determined by test bolus. We used methods of MIP and VRT in all cases, and Fly-through in cerebral aneurysms, to display and analyze the cerebral vessels. 20 cases that were judged normal by CTA were draw-out respectively from groupl and 2 to compose group A and group B. Cerebral arteries shown on CT image were analyzed statistically in Group A and B.In the 124 cases: (1) 48 cases were suspected aneurysms, of which 38 cases were examined by both DSA and CTA within ten days and 16 cases were operated. (2) 37 cases were suspected vascular malformation, of which 7 cases were examined by DSA and 14 cases had an operation. (3) 26 cases were suspected ischemic cerebrovascular diseases, of which 19 cases underwent MRI and MRA. (4) 13 cases were counterchecked after operation. Then we contrasted the results of CTA of aneurysmsand vascular malformation with the results of DSA and operation; ischemic cerebrovascular diseases with MRI and MRA.Results: Every branch of cerebral vessels in Group B appeared much better than that in Group A. The delay time of group A was 17s and the mean delay time of group B was 18s. After a statistical analysis, larger arteries grade in Group A and B were significantly different(P< 0.05).In 38 cases suspected aneurysms and examined by both CTA and DSA, 13 cases were identically diagnosed normal by the two techniques. For the rest 25 cases, CTA diagnosed aneurysms in 23 cases (27 pathological changes) and normal in 2 cases. Compared to DSA, 21 cases (25 changes) of CTA were consistent with that of DSA, two lesions were missed and two were misdiagnosed. Two cases of normal were diagnosed by DSA were falsely diagnosed aneurysms of posterior cerebral artery and anterior communicating artery by CTA. Two cases of aneurysms of posterior communicating artery were diagnosed by DSA were diagnosed normal by CTA. The sensitivity was 92.6% and the specificity was 86.7%. In 15 of 16 cases of operation, the location, shape and neck of aneurysms were identical to the operational findings and 1 case was meningioma.Vascular malformation diagnosed by CTA totaled 25 of 37 cases, including 12 cavernous angiomas of brain, 7 AVM and 6 venous malformation. In 7 of 25 cases examined by DSA, only 3 were detected and 4 were diagnosed normal, which were diagnosed cavernous angiomas of brain by CTA. The 12 cases were operated, consisting of 5 AVM, 6 cavernous angiomas of brain and 1 meningioma. The results of CTA and operation in 4 AVM and 5 cavernous angiomas of brain were same. 1 case of AVM was misdiagnosed cavernous angiomas of brain, another case of meningioma was misdiagnosed AVM by CTA. Two cases of AVM were diagnosed by the operation were falsely diagnosed normal by CTA.In 26 cases suspected ischemic cerebrovascular diseases, CTA diagnosed 16 cerebral infarction, 2 venous sinus thrombosis, 1 prolong and expansion of basilar artery and 7 normal. Only 4 cases showed cerebrovascular changes in cerebral infarction, 3 cases in middle cerebral artery and 1 case in middle cerebral artery andinternal carotid artery attaching calcification. One venous sinus thrombosis located in superior sagittal sinus, another located continually in superior sagittal sinus, transverse sinus, sigmoid sinus, straight sinus and confluence of sinus. The vascular changes shown by CTA were identical to MRA.13 cases were rechecked after operation, including 7 aneurysms and 6 AVM. The CTA images of aneurysms may demonstrate clearly the location and shape of the clip and the extent of vascular filling. The CTA images of AVM can display the remains of vascular malformation and the information of removing feeding arteries and draining veins.Conclusion: Test bolus can determine delay time more exactly and show the cerebral arteries more clearly. The diagnosis value of 16-slice spiral CTA for cerebral vascular diseases is affirmative, especially for cerebral aneurysms. Owing to the fact that there were insufficient cases, it should be studied further as to the diagnosis value for vascular malformation, ischemic cerebrovascular diseases, venous sinus thrombosis and prolong and expansion of basilar artery.