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Karl-Fredrik Lindegaard, Søren Jacob Bakke, Peter Grolimund, Rune Aaslid, Peter Huber, and Helge Nornes

✓ Noninvasive transcranial Doppler recordings were correlated to the angiographic findings in 77 patients with carotid artery disease. Stenoses reducing the luminal area of the internal carotid artery by 75% or more also reduced the pulsatility transmission index (PTI) of the ipsilateral middle cerebral artery (MCA). The PTI is the pulsatility index of the artery under study expressed as a percent of the pulsatility index of another intracranial artery with presumed unimpeded inflow in the same individual. For stenoses in the 75% to 89% category, PTI reduction was significantly greater in patients with bilateral carotid stenosis, indicating an impaired potential for collateral flow in these patients. The PTI reduction probably reflects both the pressure drop across the stenosis and the cerebral autoregulatory response. Two criteria proved useful in demonstrating collateral MCA supply through the circle of Willis. On the recipient side, retrograde flow in the proximal anterior cerebral artery was demonstrated in 29 of the 31 patients when this flow pattern was disclosed angiographically. In 26 of these patients, the anterior cerebral artery on the supplying side also had clearly increased flow velocity. Increased flow velocities in the proximal posterior cerebral artery were present in 26 of the 30 vessels that were acting as a collateral channel to the ipsilateral MCA.

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Mark P. Garrett, Richard W. Williamson, Michael A. Bohl, C. Roger Bird, and Nicholas Theodore

have attempted to show the reliability of CTA in demonstrating a lack of intracranial blood flow in the brain-dead patient. 1–3 , 5–10 , 12–15 , 17–19 However, these studies are highly heterogeneous in terms of the comparison studies they use as gold standards; some appropriately use clinical criteria alone, whereas others use a combination of clinical criteria and any one or a combination of the AAN-recommended ancillary tests. The use of ancillary tests other than CA as gold standards to compare with CTA is problematic, as many of these studies have a statistical

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Joanna M. Wardlaw and James C. Cannon

✓ “Color Doppler energy” (or “power Doppler”), a new color Doppler ultrasound technique that is independent of flow direction and very sensitive to movement, was assessed for its use in the identification of intracranial aneurysms in patients with recent subarachnoid hemorrhage immediately prior to using cerebral angiography. Features that identified aneurysms using this technique included the appearance of abnormal color where no normal artery was expected, abnormal bulging of an artery, and greater “expansibility” of the aneurysm in comparison to an adjacent normal vessel. In this exploratory study, 30 of 33 aneurysms were correctly identified in 35 patients with a good bone window. Color Doppler energy is considerably more sensitive to intracranial blood flow than conventional color Doppler imaging. Color Doppler energy is a useful research tool; if these preliminary results are verified in larger series, in addition to examination for vasospasm, the technique could be used for identification and follow up of aneurysms.

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Ricardo Santos de Oliveira and Hélio Rubens Machado

Object

Hydrocephalus is a common disease process. Transcranial color-coded Doppler (TCCD) ultrasonography is an accepted noninvasive method with which to quantify intracranial blood flow in adults and children. The authors studied the applications of TCCD ultrasonography and the alterations of the flow velocity of the cerebral arteries in children with hydrocephalus.

Methods

One hundred thirty-five children were divided into three groups: Group 1 comprised 40 infants with asymptomatic hydrocephalus who had well-functioning ventriculoperitoneal (VP) shunts; Group 2 comprised 10 children with symptomatic hydrocephalus who had malfunctioning shunts that were replaced; and Group 3 was a control group of 85 healthy infants. All patients underwent sequential measurements of cerebral blood flow (CBF) velocities (systolic and diastolic velocities) and resistivity index (RI). One group of patients underwent functional tests (compression of the anterior fontanelle and CO2 vasoreactivity) to determine hemodynamic changes in cerebral circulation.

A significant statistical change in RI measurements, end diastolic CBF velocity, and percentage of change in RI was shown in patients with malfunctioning shunts, and in infants with a well-functioning VP shunt vasomotor reactivity was severely reduced.

Conclusions

Transcranial color-coded Doppler ultrasonography can be used to perform follow-up assessments of normal and malfunctioning shunts in children with hydrocephalus; the functional tests are a noninvasive tool for evaluating the cerebral compliance and the cerebral autoregulation in infants with hydrocephalus. The autoregulatory capacity may partly or completely be lost in cases of long-term shunt-treated hydrocephalus, and loss of cerebral vasoreactivity may be responsible for long-term deficits commonly observed in children, which help explain some of symptoms related to slit ventricles.

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Mitsunobu Nakamura, Hideaki Imai, Kenjiro Konno, Chisato Kubota, Koji Seki, Sandra Puentes, Ahmad Faried, Hideaki Yokoo, Hidekazu Hata, Yuhei Yoshimoto, and Nobuhito Saito

Object

Encephalomyosynangiosis (EMS) is a surgical treatment for moyamoya disease that is widely used to provide increased intracranial blood flow via revascularization by arterial anastomosis from the external carotid artery. However, the angiogenic mechanism responsible for the revascularization induced by EMS has not been systematically evaluated. In this study the authors investigated the chronological angiogenic changes associated with EMS to clarify the favorable factors and identify revascularization mechanisms by using an experimental internal carotid artery occlusion (ICAO) model in the miniature pig.

Methods

Fourteen miniature pigs were used, 11 of which underwent ICAO before transcranial surgery for EMS was performed. Animals were allowed to recover for 1 week (4 pigs) or 4 weeks (7 pigs) after EMS. Control group animals were treated in the same way, but without occlusion (3 pigs). Magnetic resonance imaging, angiography, and histological investigation were performed.

Results

One week after EMS, on histological examination of both the ICAO and control groups it was found that the transplanted temporal muscle had adhered to the arachnoid via a granulation zone, which was enriched with immune cells such as macrophages associated with the angiogenic process. Four weeks after EMS, angiography and histological examination of the ICAO group showed patent anastomoses between the external carotid artery and the cortical arteries without any detectable boundary between the temporal muscle and the cerebral cortex. In contrast, histological examination of the control group found scar tissue between the cerebral cortex and temporal muscle.

Conclusions

The initial step for formation of anastomoses resembles the process of wound healing associated with repair processes such as active proliferation of macrophages and angiogenesis within the new connective tissue. Functional revascularization requires a suitable environment (such as tissue containing vascular beds) and stimulus (such as ischemia) to induce vascular expansion.

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. References 1. Chan KH , Miller JD , Dearden NM : Intracranial blood flow velocity after head injury: relationship to severity of injury, time, neurological status and outcome. J Neurol Neurosurg Psychiatry 55 : 787 – 791 , 1992 Chan KH, Miller JD, Dearden NM: Intracranial blood flow velocity after head injury: relationship to severity of injury, time, neurological status and outcome. J Neurol Neurosurg Psychiatry 55: 787–791, 1992 2. Taylor AR , Bell TK : Slowing of cerebral circulation after

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Shoichiro Kawaguchi, Toshisuke Sakaki, Shuzo Okuno, Yoshitomo Uchiyama, and Toshikazu Nishioka

dizziness. At the age of 10 years this patient had undergone bilateral superficial temporal artery—middle cerebral artery bypasses for moyamoya disease. Right ICA angiography revealed an aneurysm approximately 5 mm distal, clearly away from the origin of the OphA that functioned as the collateral pathway for intracranial blood flow ( Fig. 1 upper ). Right OphA CDF velocimetry imaging demonstrated that the peak systolic flow velocity was 0.51 m/second and that the resistance index was 0.53 ( Fig. 1 lower ). The aneurysm was clipped to prevent enlargement and rupture

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O. Howard Reichman

resulted between the thin wall of the basilar artery and the thick wall of the lingual artery ( Fig. 3 ). Two open anastomoses closed later, and two others became severely narrowed. Fig. 2. Arteriogram 18 days after anastomosis ( arrow ). Rich intracranial blood flow through the lingual-basilar system was demonstrated again at 18 months. Actual size. Fig. 3. Cross section through the anastomosis 15 days after surgery. Dotted lines demarcate the lingual artery ( LA ) and basilar artery ( BA ), which are nicely approximated. Smooth intimal surface

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Neurosurgery JNS 0022-3085 1933-0693 American Association of Neurological Surgeons 2015.6.JNS.AANS2014ABSTRACTS Women in Neurosurgery Louise Eisenhardt Traveling Scholarship 656. Effects of Extracranial Carotid Stenosis on Intracranial Blood Flow Sophia F. Shakur , MD , Tomas Hrbac , MD, PhD , Ali Alaraj , MD , Xinjian Du , MD , Victor Aletich , MD , Fady Charbel , MD , and Sepideh Amin-Hanjani , MD (Chicago, IL) 6 2015 122 6 History of Craniotomy, Cranioplasty, and

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Unilateral Vertebral Artery Ligation

Report of a Case Ending Fatally with Thrombosis of the Basilar Artery

Lyle A. French and Gerald L. Haines

, thrombosis is rarely found. Dandy 2 believed that thrombosis and embolism are of extreme importance. Holman 4 commented on the advantages of fractional ligation. The final answer seems yet to come, as the important problem of vascular stasis remains nearly untouched. In our case it seems probable that there was intimal damage at the time of ligation with resulting thrombosis, but that in addition, the enlarged vertebral artery was carrying an unusually large proportion of the total intracranial blood flow, which, when cut off, produced fatal ischemia. SUMMARY A