3D Computerized Occlusion Rating of Embolized Experimental Aneurysms Using Noninvasive 1.5T MR Imaging

• Published in: American journal of neuroradiology : AJNR Vol. 33; no. 4; pp. 661 - 666
• Main Authors: SHERIF, C, MARBACHER, S, FANDINO, J, ERHARDT, S, NEUSCHMELTING, V, KILLER, M, MACH, G, REMONDA, L
• Format: Journal Article
• Language: English
• Published: Oak Brook, IL American Society of Neuroradiology 01-04-2012
• Subjects: Aneurysm; Aneurysm - pathology; Aneurysm - surgery; Animals; Biological and medical sciences; Carotid Artery Diseases - pathology; Carotid Artery Diseases - surgery; Cerebral blood flow; Computed tomography; Computers; Disease Models, Animal; Embolization; Female; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Imaging, Three-Dimensional - methods; Interventional; Investigative techniques, diagnostic techniques (general aspects); Ischemia; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Medical sciences; Neck; Nervous system; Nervous system (semeiology, syndromes); Nervous system as a whole; Neuroimaging; Neurology; Prognosis; Rabbits; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Reproducibility of Results; Sensitivity and Specificity; Statistics; Treatment Outcome; Vascular disease; Occlusion; Nervous system diseases; Radiodiagnosis; Aneurysm; Cardiovascular disease; Nuclear magnetic resonance imaging
• ISSN: 0195-6108; 1936-959X
• DOI: 10.3174/ajnr.A2843

For embolized cerebral aneurysms, the initial occlusion rate is the most powerful parameter to predict aneurysm rerupture and recanalization. However, the occlusion rate is only estimated subjectively in clinical routine. To minimize subjective bias, computer occlusion-rating (COR) was successfully validated for 2D images. To minimize the remaining inaccuracy of 2D-COR, COR was applied to 1.5T 3D MR imaging.
Twelve experimental rabbit aneurysms were subjected to stent-assisted coil embolization followed by 2D DSA and 3D MR imaging. Subjective occlusion-rate (SOR) was estimated. Linear parameters (aneurysm length, neck width, parent vessel diameter) were measured on 2D DSA and 3D MR imaging. The occlusion rate was measured by contrast medium-based identification of the nonoccluded 2D area/3D volume in relation to the total aneurysm 2D area/3D volume. 2D and 3D parameters were statistically compared.
There were no limiting metallic artifacts by using 3D MR imaging. Linear parameters (millimeters) were nearly identical on 2D DSA and 3D MR imaging (aneurysm length: 7.5 ± 2.6 versus 7.4 ± 2.5, P = .2334; neck width: 3.8 ± 1.0 versus 3.7 ± 1.1, P = .6377; parent vessel diameter: 2.7 ± 0.6 versus 2.7 ± 0.5, P = .8438), proving the high accuracy of 3D MR imaging. COR measured on 3D MR imaging was considerably lower (61.8% ± 26.6%) compared with the following: 1) 2D-COR (65.6% ± 27.1%, P = .0537) and 2) 2D-SOR estimations (69.2% ± 27.4%, P = .002). These findings demonstrate unacceptable bias in the current clinical standard SOR estimations.
3D-COR of embolized aneurysms is easily feasible. Its accuracy is superior to that of the clinical standard 2D-SOR. The difference between 3D-COR and 2D-COR approached statistical significance. 3D-COR may add objectivity to the ability to stratify the risk of rerupture in embolized cerebral aneurysms.