• Tomoaki Suzuki, Hiroyuki Takao, Takashi Suzuki, Yukinao Kambayashi, Mitsuyoshi Watanabe, Hiroki Sakamoto, Issei Kan, Kengo Nishimura, Shogo Kaku, Toshihiro Ishibashi, Satoshi Ikeuchi, Makoto Yamamoto, Yukihiko Fujii, and Yuichi Murayama.
• *Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan; ‡Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan; §Graduate School of Mechanical Engineering and ¶Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.
• Neurosurgery. 2016 Oct 1; 79 (4): 589-95.

BackgroundThin-walled regions (TWRs) of cerebral aneurysms are at high risk of rupture, and careful attention should be paid during surgical procedures. Despite this, an optimal imaging technique to estimate TWRs has not been established. Previously, pressure elevation at TWRs was reported with computational fluid dynamics (CFD) but not fully evaluated.ObjectiveTo investigate the possibility of predicting aneurysmal TWRs at high-pressure areas with CFD.MethodsFifty unruptured middle cerebral artery aneurysms were analyzed. Spatial and temporal maximum pressure (Pmax) areas were determined with a fluid-flow formula under pulsatile blood flow conditions. Intraoperatively, TWRs of aneurysm domes were identified as reddish areas relative to the healthy normal middle cerebral arteries; 5 neurosurgeons evaluated and divided these regions according to Pmax area and TWR correspondence. Pressure difference (PD) was defined as the degree of pressure elevation on the aneurysmal wall at Pmax and was calculated by subtracting the average pressure from the Pmax and dividing by the dynamic pressure at the aneurysm inlet side for normalization.ResultsIn 41 of the 50 cases (82.0%), the Pmax areas and TWRs corresponded. PD values were significantly higher in the correspondence group than in the noncorrespondence group (P = .008). A receiver-operating characteristic curve demonstrated that PD accurately predicted TWRs at Pmax areas (area under the curve, 0.764; 95% confidence interval, 0.574-0.955; cutoff value, 0.607; sensitivity, 66.7%; specificity, 82.9%).ConclusionA high PD may be a key parameter for predicting TWRs in unruptured cerebral aneurysms.AbbreviationsCFD, computational fluid dynamicsMCA, middle cerebral arteryPave, average pressurePD, pressure differencePmax, maximum pressureTWR, thin-walled regionWSS, wall shear stress.

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