Cerebral blood flow patterns at major vessel bifurcations and aneurysms in rats

✓ Cerebral arterial bifurcations in rats were treated to induce cerebral aneurysms experimentally, and flow patterns of latex particles introduced under a constant flow rate were analyzed with a 16-mm cine-camera and videocassette recorder. Cerebral aneurysms were produced by ligating one common carotid artery, inducing experimental hypertension, and feeding the animals β-aminopropionitrile. After perfusion and fixation, samples of cerebral arterial bifurcations with shallow invaginations and with small aneurysms were obtained and used for analysis. Bifurcations in rats without experimental treatment were used as control specimens. Flow studies in the control bifurcations showed that the apical intimal pad, not the apex itself, acted as the flow divider. Small particles tended to accumulate at the region just distal to the apical intimal pad, where the initial aneurysmal changes are known to occur. This indicates stagnation of flow at that site. In the bifurcations with shallow invaginations and small aneurysms, a marked pressure gradient was present at the proximal end of the aneurysm orifice. A tendency for stagnation of small particles near the aneurysm wall was also observed. The wall shear stress was highest at the distal end of the aneurysmal orifice, which may be responsible for the development of these lesions.

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Histologically verified cerebral aneurysm formation secondary to embolism from cardiac myxoma

Journal of Neurosurgery ◽

10.3171/jns.1995.83.1.0170 ◽

1995 ◽

Vol 83 (1) ◽

pp. 170-173 ◽

Cited By ~ 39

Author(s):

Kazuhide Furuya ◽

Tomio Sasaki ◽

Yuhei Yoshimoto ◽

Yoshifumi Okada ◽

Takamitsu Fujimaki ◽

...

Keyword(s):

Tumor Cells ◽

Cardiac Tumor ◽

Arterial Wall ◽

Cardiac Myxoma ◽

Cerebral Aneurysms ◽

Surgical Removal ◽

Arterial Aneurysm ◽

Content Type ◽

Aneurysm Formation ◽

Aneurysm Wall

✓ Multiple aneurysm formation secondary to an embolism from the cardiac myxoma is a well-known phenomenon. The cerebral arterial aneurysm formation process involved remains to be elucidated, although occupation of the arterial wall by tumor cells has been proven histologically. The authors present the case of a patient in whom tumor cells in the aneurysm wall were demonstrated and penetration of viable myxoma cells into the wall was also observed 19 months after surgical removal of the cardiac tumor. Such findings have never before been verified histologically. In light of the histological findings, the authors discuss the therapeutic problems associated with cerebral aneurysms resulting from cardiac myxoma.

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Experimental induction of cerebral aneurysms in monkeys

Journal of Neurosurgery ◽

10.3171/jns.1987.67.6.0903 ◽

1987 ◽

Vol 67 (6) ◽

pp. 903-905 ◽

Cited By ~ 105

Author(s):

Nobuo Hashimoto ◽

Choegon Kim ◽

Haruhiko Kikuchi ◽

Masayuki Kojima ◽

Yoo Kang ◽

...

Keyword(s):

Carotid Artery ◽

Internal Carotid ◽

Cerebral Aneurysms ◽

Anterior Communicating Artery ◽

Experimental Hypertension ◽

Content Type ◽

Experimental Induction ◽

The Common ◽

The Brain ◽

Fine Print

✓ Saccular cerebral aneurysms were successfully induced in two monkeys treated with ligation of the common carotid artery, experimental hypertension, and β-aminopropionitrile feeding. The cerebral aneurysms developed on the large arteries at the base of the brain, such as the anterior communicating artery and the internal carotid artery at the origin of the posterior communicating artery. Because of the similarity of the monkey to man as a species, the present results strongly suggest the significance of postnatal aggravating factors in the development of cerebral aneurysms in man.

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Flow changes caused by the sequential placement of stents across the neck of sidewall cerebral aneurysms

Journal of Neurosurgery ◽

10.3171/jns.2005.103.5.0891 ◽

2005 ◽

Vol 103 (5) ◽

pp. 891-902 ◽

Cited By ~ 102

Author(s):

Gádor Cantón ◽

David I. Levy ◽

Juan C. Lasheras ◽

Peter K. Nelson

Keyword(s):

Shear Stress ◽

Velocity Field ◽

Cerebral Aneurysms ◽

Parent Artery ◽

Shear Stresses ◽

Content Type ◽

Aneurysm Neck ◽

Aneurysm Wall ◽

Aneurysm Model ◽

Fine Print

Object. The goal of this study was to quantify the reduction in velocity, vorticity, and shear stresses resulting from the sequential placement of stents across the neck of sidewall cerebral aneurysms. Methods. A digital particle image velocimetry (DPIV) system was used to measure the pulsatile velocity field within a flexible silicone sidewall intracranial aneurysm model and at the aneurysm neck–parent artery interface in this model. The DPIV system is capable of providing an instantaneous, quantitative two-dimensional measurement of the velocity vector field of “blood” flow inside the aneurysm pouch and the parent vessel, and its changes at varying stages of the cardiac cycle. The corresponding vorticity and shear stress fields are then computed from the velocity field data. Three Neuroform stents (Boston Scientific/Target), each with a strut thickness between 60 and 65 µm, were subsequently placed across the neck of the aneurysm model and measurements were obtained after each stent had been placed. The authors measured a consistent decrease in the values of the maximal averaged velocity, vorticity, and shear stress after placing one, two, and three stents. Measurements of the circulation inside the sac demonstrated a systematic reduction in the strength of the vortex due to the stent placement. The decrease in the magnitude of the aforementioned quantities after the first stent was placed was remarkable. Placement of two or three stents led to a less significant reduction than placement of the first stent. Conclusions. The use of multiple flexible intravascular stents effectively reduces the strength of the vortex forming in an aneurysm sac and results in a decrease in the magnitude of stresses acting on the aneurysm wall.

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Morphological and Hemodynamic Changes during Cerebral Aneurysm Growth

Brain Sciences ◽

10.3390/brainsci11040520 ◽

2021 ◽

Vol 11 (4) ◽

pp. 520

Author(s):

Emily R. Nordahl ◽

Susheil Uthamaraj ◽

Kendall D. Dennis ◽

Alena Sejkorová ◽

Aleš Hejčl ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Kinetic Energy ◽

Swirling Flow ◽

Morphological Changes ◽

Cerebral Aneurysms ◽

Patient Specific ◽

Aneurysm Wall ◽

Aneurysm Growth ◽

Computational Fluid Dynamics Cfd

Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic properties related to the rupture of cerebral aneurysms. Few of these studies deal specifically with aneurysm growth and most only use a single time instance within the aneurysm growth history. The present retrospective study investigated four patient-specific aneurysms, once at initial diagnosis and then at follow-up, to analyze hemodynamic and morphological changes. Aneurysm geometries were segmented via the medical image processing software Mimics. The geometries were meshed and a computational fluid dynamics (CFD) analysis was performed using ANSYS. Results showed that major geometry bulk growth occurred in areas of low wall shear stress (WSS). Wall shape remodeling near neck impingement regions occurred in areas with large gradients of WSS and oscillatory shear index. This study found that growth occurred in areas where low WSS was accompanied by high velocity gradients between the aneurysm wall and large swirling flow structures. A new finding was that all cases showed an increase in kinetic energy from the first time point to the second, and this change in kinetic energy seems correlated to the change in aneurysm volume.

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Prevalence of cerebral aneurysms in patients with persistent primitive trigeminal artery

Journal of Neurosurgery ◽

10.3171/jns.1999.90.5.0865 ◽

1999 ◽

Vol 90 (5) ◽

pp. 865-867 ◽

Cited By ~ 56

Author(s):

Harry J. Cloft ◽

Nasser Razack ◽

David F. Kallmes

Keyword(s):

Intracranial Aneurysms ◽

Case Reports ◽

Cerebral Aneurysms ◽

Trigeminal Artery ◽

Content Type ◽

Persistent Primitive Trigeminal Artery ◽

Unbiased Manner ◽

Primitive Trigeminal Artery ◽

Fine Print ◽

Saccular Aneurysms

Object. The aim of this study was to determine the prevalence of cerebral saccular aneurysms in patients with persistent primitive trigeminal artery (PPTA). The prevalence of cerebral saccular aneurysms in patients with PPTA previously has been reported to be 14 to 32%, but this rate range is unreliable because it is based on collections of published case reports rather than a series of patients chosen in an unbiased manner.Methods. The authors retrospectively evaluated their own series of 34 patients with PPTA to determine the prevalence of cerebral aneurysms in this population. The prevalence of intracranial aneurysms in patients with PPTA was approximately 3% (95% confidence interval 0–9%).Conclusions. The prevalence of intracranial aneurysms in patients with PPTA is no greater than the prevalence of intracranial aneurysms in the general population.

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MTI (Dendron) Variable Detachable Coils

Interventional Neuroradiology ◽

10.1177/159101990300900106 ◽

2003 ◽

Vol 9 (1) ◽

pp. 47-52

Author(s):

J. Thammaroj ◽

V. Jayakrishnan ◽

S. Lamin ◽

S. Jenkins ◽

E. Teasdale ◽

...

Keyword(s):

Endovascular Treatment ◽

Feasibility Study ◽

Clinical Experience ◽

Cerebral Aneurysms ◽

Detachable Coils ◽

Formed Part ◽

Small Aneurysms ◽

Initial Clinical Experience

We present our initial clinical experience of Dendron Variable Detachable System (VDS) coils, now Sapphire VDS from MTI, in the endovascular treatment of cerebral aneurysms. VDS coils, uniquely, can be detached at variable points along their length, allowing placement of as much or as little as desired of the coil within the aneurysm. Our ten patients formed part of a multicentre feasibility study. VDS coils were successfully deployed in all but one aneurysm. The electrolytic detachment mechanism with practice is both simple to use and reliable. The coils are however slightly stiffer than standard coils limiting their use in small aneurysms. This remains a technology in evolution.

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Surgery for angiographically occult cerebral aneurysms

Journal of Neurosurgery ◽

10.3171/jns.1993.79.5.0674 ◽

1993 ◽

Vol 79 (5) ◽

pp. 674-679 ◽

Cited By ~ 47

Author(s):

Jafar J. Jafar ◽

Howard L. Weiner

Keyword(s):

Cerebral Aneurysms ◽

Artery Aneurysm ◽

Sylvian Fissure ◽

Ct Scans ◽

Anterior Communicating Artery ◽

Content Type ◽

Excellent Outcome ◽

Interpeduncular Cistern ◽

Spontaneous Subarachnoid Hemorrhage ◽

Exploratory Surgery

✓ In 15% of patients with spontaneous subarachnoid hemorrhage (SAH), the source of bleeding cannot be determined despite repeated cerebral angiography. However, some patients diagnosed as having “SAH of unknown cause” actually harbor undetected aneurysms. The authors report six patients with SAH who, despite multiple negative cerebral angiograms, underwent exploratory surgery due to a high clinical and radiographic suspicion for the presence of an aneurysm. Brain computerized tomography (CT) scans revealed blood located mainly in the basal frontal interhemispheric fissure in four patients, in the sylvian fissure in one patient, and in the interpeduncular cistern in one patient. The patients were evaluated as Hunt and Hess Grades I to III, and had undergone at least two high-quality cerebral angiograms that did not reveal an aneurysm. Vasospasm was visualized in two patients. Three patients rebled while in the hospital. Exploratory surgery was performed at an average of 12 days post-SAH. Five aneurysms were discovered at surgery and were successfully clipped. All four patients with interhemispheric blood were found to have an anterior communicating artery (ACoA) aneurysm. The patient with blood in the sylvian fissure was found to have a middle cerebral artery aneurysm. These aneurysms were partially thrombosed. No aneurysm was detected in the patient with interpeduncular SAH, despite extensive basilar artery exploration. Five patients had an excellent outcome and one patient developed diabetes insipidus. These results show that exploratory aneurysm surgery is warranted, despite repeated negative cerebral angiograms, if the patient manifests the classical signs of SAH with CT scans localizing blood to a specific cerebral blood vessel (particularly the ACoA) and if a second SAH is documented at the same site.

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CT infusion scanning for the detection of cerebral aneurysms

Journal of Neurosurgery ◽

10.3171/jns.1989.71.2.0175 ◽

1989 ◽

Vol 71 (2) ◽

pp. 175-179 ◽

Cited By ~ 39

Author(s):

David W. Newell ◽

Peter D. LeRoux ◽

Ralph G. Dacey ◽

Gary K. Stimac ◽

H. Richard Winn

Keyword(s):

Intracerebral Hemorrhage ◽

Ct Scan ◽

Computerized Tomography ◽

Cerebral Aneurysms ◽

Spontaneous Intracerebral Hemorrhage ◽

Content Type ◽

Spontaneous Hemorrhage ◽

Fine Print

✓ Computerized tomography (CT) infusion scanning can confirm the presence or absence of an aneurysm as a cause of spontaneous intracerebral hemorrhage. Eight patients who presented with spontaneous hemorrhage were examined using this technique. In five patients the CT scan showed an aneurysm which was later confirmed by angiography or surgery; angiography confirmed the absence of an aneurysm in the remaining three patients. This method is an easy effective way to detect whether an aneurysm is the cause of spontaneous intracerebral hemorrhage.

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