Unilateral Approach for Bilateral Middle Cerebral Artery Aneurysms Assisted by Preoperative Understanding of Aneurysm Wall Properties: Two-Dimensional Operative Video.

Unruptured middle cerebral artery (MCA) aneurysms often exist bilaterally, and a unilateral approach for bilateral MCA aneurysms has been reported; however, this remains challenging because there are various technical nuances.1-4 Wall properties have been reported to be an important issue for this strategy.2,3 Atherosclerotic changes in the aneurysm wall can make clipping difficult. We present a video case demonstrating clipping of bilateral MCA aneurysms via a unilateral craniotomy assisted by preoperative understanding of the aneurysm wall properties using computational fluid dynamic analysis (Video 1). A 71-year-old woman had bilateral MCA bifurcation aneurysms. The oscillatory shear index color map by computational fluid dynamic analysis demonstrated that the contralateral MCA aneurysm did not have a high oscillatory shear index area in the dome, which means that there was no wall thickening, and the ipsilateral MCA aneurysm had scattered high oscillatory shear index areas, which were expected to have extreme wall thickening.5 After pterional craniotomy, the sylvian fissure was widely opened. As expected, the contralateral MCA aneurysm did not have a thick-walled region, enabling simple neck clipping using a straight clip. In contrast, the ipsilateral MCA aneurysm had thick-walled areas, as predicted, necessitating a multiple clip application. Postoperatively, the patient was discharged without any neurological deficits. Prediction of aneurysm wall properties using computational fluid dynamic analysis could assist in determining clippability of intracranial aneurysms, especially for aneurysms approached by narrow and deep surgical fields, such as contralateral MCA aneurysms. The patient consented to the procedure and the publication of their images.

Newly Identified Hemodynamic Parameter to Predict Thin-Walled Regions of Unruptured Cerebral Aneurysms Using Computational Fluid Dynamics Analysis.

BACKGROUND: The thin-walled regions (TIWRs) of intracranial aneurysms have a high risk of rupture during surgical manipulation. They have been reported to be predicted by wall shear stress and pressure (PS) based on computational fluid dynamics analysis, although this remains controversial. In this study, we investigated whether the oscillatory shear index (OSI) can predict TIWRs. METHODS: Twenty-five unruptured aneurysms were retrospectively analyzed; the position and orientation of the computational fluid dynamics color maps were adjusted to match the intraoperative micrographs. The red area on the aneurysm wall was defined as TIWR, and if most of the regions on the color map corresponding to TIWR were OSI low (lower quartile range), time-averaged wall shear stress (TAWSS) high, or PS high (upper quartile range), each region was defined as a matched region and divided by the total number of TIWRs to calculate the match rate. In addition, the mean values of OSI, TAWSS, and PS corresponding to TIWRs were quantitatively compared with those in adjacent thick-walled regions. RESULTS: Among 27 TIWRs of 25 aneurysms, 23, 10, and 14 regions had low OSI, high TAWSS, and high PS regions (match rate: 85.2%, 37.0%, and 51.9%), respectively. Receiver operating characteristic curve analysis demonstrated that OSI was the most effective hemodynamic parameter (area under the curve, 0.881), followed by TAWSS (0.798). Multivariate analysis showed that OSI was a significant independent predictor of TIWRs (odds ratio, 18.30 [95% CI, 3.2800-102.00], P < 0.001). CONCLUSIONS: OSI may be a unique predictor for TIWRs. Low OSI strongly corresponds with TIWRs of intracranial aneurysms.

Output of radiopharmaceutical nuclides of known injected doses from a municipal sewage treatment system.

The concentrations of (99m)Tc, (123)I, (67)Ga, and (201)Tl of the discharge water and the sewage sludge from Kurume Central Sewage Treatment Plant were determined once a week for 2 mo. The radiopharmaceutical doses injected into the patients for all of four hospitals that use nuclear medicines in the service area of the plant were also surveyed. Approximately 1.5% of the (99m)Tc, 1.5% of the (123)I, 4.3% of the (67)Ga, and 0.41% of the (201)Tl of the injected doses were detected in the discharged water from the plant. The behavior of these radionuclides in the sewage treatment system was analyzed using a compartment model. The analyses suggest that the average residence times in storage tanks and drainage pipes before entering the plant were 9.5 h for (99m)Tc, 81 h for (123)I, 120 h for (67)Ga, and 480 h for (201)Tl.