Clinical Application Of High Field MR Imaging In Large Unruptured Intracranial Aneurysms

Background The height and diameter of aneurysms and the relation between aneurysm and its surrounding structure is important referring information for aneurysmal surgery design. Time of flight(TOF) magnetic response angiography(MRA) is a new magnetic artery angiography arising in resent 20 years. The emergence of high field magnetic resonance imaging(MRI) making it comparable with digital subtraction angiography(DSA) and computer tomography angiography(CTA). Combining with high resolution scanning technique, MRI can also recognize aneurysmal wall and the clots in aneurysm. Following the prevalence of MRA and CTA, the detection rate of unruptured intracranial aneurysm(UIA) is increasing. However, the overall rupture risk of UIA is less than 2% even though its high mortality and disabilityafter rupture, but preventive surgery can has as high mortality and disability rate as 1.5% and 10% respectively. Inflammation plays a key role in the rupture of aneurysm, so the correct appraisement of inflammation in aneurysm can facilitate the prediction of rupture risk of aneurysms, which can help prevent an over surgery.Objective 1. Appraise the efficiency and utility of reconstructing aneurysms with MRA data by 3D-slicer software.2. Study the relationship between inflammation and aneurysmal wall enhancement in HRMRI by the method of Immunohistochemistry staining.Method Part One Let the inpatients with large or giant UIA take MRA scan, import the data into 3D-slicer software in DICOM format, reconstruct the aneurysms with "Editor" module, and then measure the height and width of aneurysms at the same angle as the DSA. Depict the three-dimension morphology of cots with MSDE data, fuse it with reconstructed MRA, and then rotate the fused image to match the real angle of surgical view to verify the accuracy about appraising the presence and position of pots. Part Two Learn about the enhanced region of aneurysmal wall according to the comparison between CE-HRMRI and HRMERI, mark the enhanced region by 3D-slicer software on each level of CE-HRMRI, get the specimen of corresponding region, and then mark the inflammatory cells of macrophages and T lymphocyte.Result Part One The results are as following:There is no significant statistic difference (t=-0.175, p=0.863) between the mean value measured by DSA(16.35±4.03mm) or MRA(16.36±4.13mm) on the aspect of aneurysmal height and no significant statistic difference(t=0.668,p=0.512) between DSA(16.09±6.23mm) or MRA(16.03±6.20mm) on the aspect of aneurysmal diameter.Part Two The difference between enhanced region and unenhanced region on CD4 counting has statistical significance (t=14.822, P=0.000), the mean value is (13.69±3.52) or (5.81±2.56) respectively; The CD68 counting has statistical significance (t=12.914, p=0.000) either on between two regions, the mean value is (12.63±2.92) or (4.31±1.66) respectively.Conclusion 1. The 3D-slicer MRA reconstruction and DSA measurement methods are equal to evaluate the maximum height and width of intracranial large or giant aneurysms; 2.The aneurysms reconstructed by 3D-slicer software can be rotated to any angle, and provide clinical doctors with direct and comprehensive medical images before surgery, which can facilitate the design of surgical program; 3.3D-slicer software can improve the accuracy of Specimens collection of aneurysm wall; 4. The enhanced part of IA wall has degenerative changes such as thrombus adhesion, vacuole degeneration and inner elastic layer fracture; 5. The enhanced aneurysmal wall on CE-HRMRI has an intense inflammation compared to non-enhanced aneurysmal wall.