Local Hemodynamic Conditions Associated with Focal Changes in the Intracranial Aneurysm Wall

BACKGROUND AND PURPOSE

Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively.

MATERIALS AND METHODS

Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test.

RESULTS

Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones.

CONCLUSIONS

Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.

Lack of specific symptomatology in children with acute otitis media

Although the symptoms of the acutely ill child are important both in the diagnosis and follow-up of acute otitis media (AOM), data about them are quite limited. We carried out a prospective survey by collecting information on 354 consecutive children visiting a pediatrician, otolaryngologist or general practitioner because of any kind of acute symptoms to compare symptoms of children with acute otitis media with those of children with other acute infectious diseases. The symptoms and signs observed at home were recorded by the parents before the visit and the findings in the physical examination were recorded later by the physician. AOM was diagnosed in 191 patients (54.0%). The most important symptoms increasing the likelihood of AOM significantly were ear-related symptoms, such as earache (relative risk (RR) 5.4; P < 0.001), rubbing of the ear (RR 5.0; P < 0.001) and feeling of blocked ear (RR 4.5; P < 0.05). However, only 67.7% of children younger than 2 years of age with AOM had any ear-related symptoms. The children with tympanostomy tubes had earache (47.8%) and rubbing of the ear (58.8%) of the same magnitude as did children without tubes. Rhinitis increased the likelihood of AOM (RR 2.3; P < 0.001) as did excessive crying in children older than 2 years of age (RR 3.0; P < 0.001). Fever, earache or excessive crying was present in 90.1% of patients with AOM but also in 72.4% of patients without AOM.(ABSTRACT TRUNCATED AT 250 WORDS)