Comparison Analysis Between 256-slice 3D CT Angiography And 3D Digital Subtraction Angiography In The Detection Of Intracranial Aneurysms

Objective:To compare the values of 256-slice 3D CT angiography (CTA) and 3D digital subtraction angiography (DSA) in the detection of intracranial aneurysms.Method:46 consecutive patients with highly suspected subarachnoid hemorrhage (SAH) or suspected aneurysm in magnetic resonance angiography (MRA) were undertaken both 3D-CTA and 3D digital subtraction angiography (3D-DSA). Two radiologists independently observed CT images use of blind, and one physician of neurology who engaged in vascular intervention and another radiologists jointly reviewed 3D-DSA images. With the AN number detected by 3D-DSA as the standard, the sensitivity and specificity of 3D-CTA, and also the agreement of AN number detected by the two CTA observers, and by the different approaches of CTA and DSA were assessed. With respect to the measurement of the longest diameters of aneurysm, the measurement values by 3D-DSA direct picture were used as the standard to compare the difference between the longest diameters of aneurysm in CTA-VR pictures by the two CTA observers, and to compare the difference among the measurement of the longest diameters of aneurysm among CTA-VR pictures, 3D-DSA-VR pictures and 3D-DSA direct pictures.Result:DSA revealed 49 aneurysms in 37 patients and no aneurysm in 9 patients. With respect to the overall AN detection number, there is a excellent agreement between the two CTA observers, with the sensitivity of CTA as 91.8%-93.9%(mean 92.9%), and the specificity as 81.8%-100%(mean 90.9%). For the AN with the aneurysms larger than 3mm, the sensitivity and specificity of CTA were 96.8%-100% (mean 98.4%)and 90%-100%(mean 95%) respectively. For the AN with the aneurysms smaller than 3mm, the sensitivity and specificity of CTA were 83.3%-83.3%(mean 83.3%)and 90%-100%(mean 95%) respectively. With respect to the overall AN detection number, the agreement between the different approaches of CTA and DSA were excellent (mean k=0.802, P=0.000). For the AN with the aneurysms larger than 3mm, the agreement between the different CTA observers and the different approaches of CTA and DSA were excellent (K=0.868, P=0.000 respectively; mean k=0.932, P=0.000). For the AN with the aneurysms smaller than 3mm, the agreement between the different CTA observers were excellent (K=0.850, P=0.000), and the agreement between the different observers of CTA and DSA were good (mean k=0.742, P=0.000). With respect to the measurement of the longest diameters of aneurysm, regardless of the overall measurement and the AN group measurement of the longest diameters of aneurysm larger than 3mm or smaller than 3mm, the difference of the CTA-VR picture measurement between the two CTA observers was of no statistical significance (p>0.05). The diameter of aneurysm measured by 3D-DSA-VR was longer than that measured by CTA-VR, the difference was of statistical significance (p<0.05); the difference of the picture measurement between CTA-VR and 3D-DSA direct picture was of no statistical significance (p>0.05).Conclusion:256-slice 3D CTA is an imaging method with a high sensitivity and specificity for the detection of the longest diameters of aneurysm larger than 3mm. It may be used in the diagnosis of aneurysm. However, due to its omission in AN for the aneurysm smaller than 3mm,3D-DSA check is still needed for that highly suspected aneurysm with negative CTA check. The agreement of the diagnosis between CTA observers and between the different approaches of CTA and DSA is excellent for the detection of the longest diameters of aneurysm larger than 3mm. For AN with the longest diameters of aneurysm smaller than 3mm, the agreement between CTA observers is excellent, while that between the CTA observers and DSA is good. With respect to the measurement of the longest diameters of aneurysm, there is no statistical difference between CTA-VR and DSA direct picture, CTA-VR can be applied in clinic; There is also no statistical difference among CTA observers with good repetition among observers; The diameter of aneurysm measured by DSA-VR is larger than that measured by CTA-VR, which should be taken into consideration in DSA-VR clinic application.