The Evaluation Of 64 Slice Spiral CT Bone-subtraction Angiography In Diagnosis Of Intracranial Aneurysms

Objective : To evaluate the efficacy and comparative advantages of 64-slice CT bone-subtraction angiography in diagnosis of intracranial aneurysms.Methods : From June 2006 to April 2007,a total of 108 subjects,(64 male, 44 female, range 14～79 years, mean age of 55 years) 55 cases of Spontaneous Subarachnoid hemorrhage,19 cases of intracranial hematoma, dizziness, hemiplegia in 17 cases, oculomotor nerve palsy in 3 cases, aneurysm after clip in 14 cases were studied retrospectively. 64-slice CT bone-subtraction angiography image quality was assessed and both methods MIP and VR were compared for imaging the size, shape, neck, axis point of the aneurysms and the three dimensional relationship of aneurysms to parent vessels and other branches and bone structure. The usefulness of 64-slice CT bone-subtraction angiography in intracranial aneurysms were evaluated by comparing with conventional digital subtraction angiography and intraoperative findings and evaluate the advantages and disadvantages of both.Results : CTA image qualityⅠ: 92 accounted for 85.2%,Ⅱ: 8 cases accounted for 7.4%,Ⅲ: five cases accounted for 4.6%.Ⅳ: 3 cases accounted for 2.8%. CTA patients were found positive in 74 cases, which included 40 cases of aneurysms, of which are 45 aneurysms; 15AVM;4 Carotid stenosis; Vertebral artery stenosis in 3 patients; aneurysms after clipping in 14 cases; 3 patients were uncertain because of the poor quality of image. 29 cases were normal, of which 8 cases also underwent DSA. All results were confirmed by surgery or DSA. Of these, 36 patients also received DSA checked and found 27 cases of aneurysms, 32 aneurysms; Negative in 8 cases. CTA detected all aneurysm, no false-positive or false-negative cases. DSA missed 1. The detection of aneurysms of sizes ranging from minimum of 1.8mm in diameter, and maximum of 48.7mm in diameter, more than 43 cases had 3mm of diameter, less than 3mm in 12 cases. Both of MIP and VR imaging of aneurysms morphology show rate were 100%, with neck showing 88.9%, 95.6% respectively.χ2=2.69, P>0.100; the spatial relationships of aneurysms and parent vessels show rate were 62.2%, 93.3%,χ2 =12.6. P<0.005. VR imaging method in diagnosis of intracranial aneurysms had sensitivity of 100%, specificity 72.7%; positive predictive value of 93.3% negative predictive value of 100%. MIP imaging had sensitivity of 100%, specificity of 100%. positive predictive value of 100%, negative predictive value 100%. CTA diagnostic sensitivity, specificity, positive predictive value, negative predictive value was 100%. DSA diagnostic sensitivity was 97.7% , specificity of 100% positive predictive value of 100%. negative predictive value of 88.9%. 11 patients received aneurysm clipping operation based on CTA results alone. Intraoperative findings were consistent with the results of CTA.14 cases had been taken for CTA After clipping ,we found that both of skull and clip were removed by boned subtraction method CTA .However not boned subtraction one showed the body of the aneurysm is completely obstructed and no remain of the neck of the aneurysm and the aneurysm clip is in its right position in 13 cases. 1 cases remain of the sack of the aneurysms.Conclusion: 1.The effectiveness of 64-slice CT bone-subtraction angiography appears equivalent to conventional DSA for detection and evaluation of intracranial aneurysms.2.64-slice CT bone-subtraction angiography demonstrates obvious advantages in the diagnosis of intracranial aneurysms, especially less than 3mm and which are located in cavernous sinus and skull base.3. 64-slice bone-subtraction angiography results can be used as the basis for the surgical treatment, reducing the emergency time thereby lowering the rate of re-bleeding.4.There is no difference between MIP and VR imaging in showing intracranial aneurysms's body and neck morphology . VR imaging quality is superior to MIP in showing the three dimensional relationship of aneurysms to parent vessels. The diagnosis of intracranial aneurysms by VR imaging alone may result in false positive. Joint MIP and other imaging methods could avoid misdiagnosis and missed diagnosis to the greatest extent.5. bone-subtraction CTA is not suitable for the post-operative evaluation of aneurysms.