脳動脈瘤破裂リスクを予測するための４次元ＣＴ血管造影法の開発

application/pdf脳動脈瘤の動的変化を評価する目的で、新しい4次元CT脳血管造影法Dynamic Four-dimensional CT Angiography(DFA)を開発した。チタンクリップ・乾燥骨を用いた静止モデルではアーチファクトはほぼ消失し、脳動脈瘤拍動モデルでは実際の拍動と同様であった。臨床例では、血管の収縮拡張に伴う体積変化や血管の位置が前後に移動していることが示された。以上の研究成果より、この新しい撮影法DFAを用いることにより、脳動脈瘤の病態生理を明らかにできる可能性が示された。We developed a novel dynamic 4-dimensional CT angiography to accurately evaluate dynamics in cerebral aneurysm. Movie artifacts disappeared on dynamic 4-dimensional CT angiography movies of 2 kinds of stationary phantoms (titanium clips and dry bone). In the virtual pulsating aneurysm model, pulsation on the dynamic 4-dimensional CT angiography movie resembled actual movement in terms of pulsation size. In a clinical study, dynamic 4-dimensional CT angiography showed 2-type motions : pulsation and anatomic positional changes of the cerebral artery. This newly developed 4-dimensional visualizing technique may deliver some clues to clarify the pathophysiology of cerebral aneurysms.平成20~22年度科学研究費補助金(基盤研究(C))研究成果報告書2059168

Computational fluid dynamics (CFD) using porous media modeling predicts recurrence after coiling of cerebral aneurysms

<div><p>Objective</p><p>This study aimed to predict recurrence after coil embolization of unruptured cerebral aneurysms with computational fluid dynamics (CFD) using porous media modeling (porous media CFD).</p><p>Method</p><p>A total of 37 unruptured cerebral aneurysms treated with coiling were analyzed using follow-up angiograms, simulated CFD prior to coiling (control CFD), and porous media CFD. Coiled aneurysms were classified into stable or recurrence groups according to follow-up angiogram findings. Morphological parameters, coil packing density, and hemodynamic variables were evaluated for their correlations with aneurysmal recurrence. We also calculated residual flow volumes (RFVs), a novel hemodynamic parameter used to quantify the residual aneurysm volume after simulated coiling, which has a mean fluid domain > 1.0 cm/s.</p><p>Result</p><p>Follow-up angiograms showed 24 aneurysms in the stable group and 13 in the recurrence group. Mann-Whitney U test demonstrated that maximum size, dome volume, neck width, neck area, and coil packing density were significantly different between the two groups (P < 0.05). Among the hemodynamic parameters, aneurysms in the recurrence group had significantly larger inflow and outflow areas in the control CFD and larger RFVs in the porous media CFD. Multivariate logistic regression analyses demonstrated that RFV was the only independently significant factor (odds ratio, 1.06; 95% confidence interval, 1.01–1.11; P = 0.016).</p><p>Conclusion</p><p>The study findings suggest that RFV collected under porous media modeling predicts the recurrence of coiled aneurysms.</p></div

Comparison of hemodynamic parameters using computational fluid dynamics analyses.

<p>Comparison of hemodynamic parameters using computational fluid dynamics analyses.</p

Representative cerebral aneurysm in the basilar artery (A-B).

<p>A, control computational fluid dynamics (CFD) model; B, porous media CFD. From left to right, segmentation of the neck plane (black) and intra-aneurysmal domain to define porous media (pink domain), streamline, inflow area (red), outflow area (blue), wall shear stress, and flow volume domain with a mean flow velocity > 1.0 cm/s (red domain) indicating residual flow volume (RFV) on the porous media CFD.</p

Representative cerebral aneurysms.

<p>A, right internal carotid artery aneurysm with complete occlusion; B, anterior communicating artery aneurysm with residual neck; C, right middle cerebral artery aneurysm with residual aneurysm on follow-up angiogram. From left to right, pre-coiling angiograms, post-coiling immediate angiograms, follow-up angiograms, segmentation of porous medium (pink domain), streamline at the post-coil embolization under the porous media model, and residual flow volume (RFV) with a mean flow velocity > 1.0 cm/s (red domain). Aneurysm volume (A:B:C = 54.8:255.4:146.7 mm³), coil packing density (38.7:24.3:24.7%), and RFV (3.7:27.1:56.5 mm³), respectively.</p

Schematic diagram of porous media modeling for coil embolization.

<p>Schematic diagram of porous media modeling for coil embolization.</p

Comparison of hemodynamic parameters using computational fluid dynamics analyses on transient analysis.

<p>Comparison of hemodynamic parameters using computational fluid dynamics analyses on transient analysis.</p

Univariate and multivariate logistic regression analyses of independent parameters with respect to recurrence after coiling.

<p>Univariate and multivariate logistic regression analyses of independent parameters with respect to recurrence after coiling.</p

Characteristics of unruptured cerebral aneurysms treated by coil embolization.

<p>Characteristics of unruptured cerebral aneurysms treated by coil embolization.</p