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Maria V. Lopez-Bresnahan, Lee A. Kearse Jr., Paulino Yanez and Tina I. Young

cerebral ischemia. In this retrospective study, we examined the preoperative cerebral angiograms of patients who underwent elective carotid endarterectomy to determine whether specific collateral flow patterns correlated with protection against intraoperative electroencephalographic (EEG) evidence of cerebral ischemia at carotid artery cross-clamping. Clinical Material and Methods Patient Population Between November 10, 1986, and May 30, 1991, 65 patients underwent two- to four-vessel cerebral angiography followed by carotid endarterectomy for symptomatic

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Grant A. Bateman

normal gradients, 24 and these elevated pressures open collateral vessels. This collateral flow has been measured as a reduced percentage of the sagittal sinus outflow (compared with inflow) of 32% in IIH compared with 47% in controls (p < 0.0001). 3 Similarly, in the straight sinus a percentage return of 9% in IIH compared with 14% in controls (p < 0.0001) has indicated evidence of collateral flow in the deep system. 3 In the present study, the total arterial inflow in the patients was normal, indicating that the blood flowing into the capillary bed of the brain

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Helge Nornes, Arne Grip and Per Wikeby

, while the second showed a definite reduction in flow velocity at the site of application. However, velocities in the MCA and ACA were unchanged, and the reduction in ICA velocity was simply a consequence of the local dilatation of the ICA that was seen. When volume flow is constant, velocity is inversely related to the cross-sectional area of the vessel. Collateral Flow The principles and indications for measurement of collateral flow have been discussed elsewhere. 17, 20 In spite of improved microsurgical technique during the last decade, trap ligation is

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Rune Aaslid, Thomas-Marc Markwalder and Helge Nornes

exhibited a velocity pattern as shown in Fig. 5 . The upper panel illustrates a reversal of flow in this artery when the ipsilateral CCA was compressed. The proximal ACA was supplying collateral flow to the MCA on the same side in this situation. During compression, irregular flow or turbulence could be heard in the Doppler signal, particularly in systole. This showed up in the spectra as a brief period of low-frequency noise. We interpret this as the effects of a high-velocity jet from the anterior communicating artery. A recording of the proximal ACA velocity during

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Microregional blood flow changes in experimental cerebral ischemia

Effects of arterial carbon dioxide studied by fluorescein angiography and xenon133 clearance

Y. Lucas Yamamoto, Kathryne M. Phillips, Charles P. Hodge and William Feindel

ultimate size and nature of the infarction are influenced by secondary factors such as increased intracranial pressure, local tissue acidosis, tissue edema, constriction of the cerebral arteries and arterioles, or hemorrhage into the tissue. All of these can intervene between the onset of the experimental arterial clipping and the removal and fixation of the brain for pathological examination. The extent of collateral flow has also been a variable factor in our experimental studies that appears to play a considerable role in altering the extent of the final infarct and

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Fredric B. Meyer, David G. Piepgras, Thoralf M. Sundt Jr. and Takehiko Yanagihara

cases show that 14 (58%) improved, one was unchanged, and nine (37.5%) died. Six of these deaths were related to either surgery or the actual ischemic event. There were two hemorrhagic infarctions, one of which resulted from the use of anticoagulation therapy. 42 Eighteen arteries were demonstrated to be patent either by angiography or at autopsy, and one additional patient had partial restoration of flow. 19 There were indications of good preoperative collateral flow in eight patients, 11, 15, 19, 20, 30, 32, 34, 49 seven of whom improved after surgery, supporting

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Charles G. Drake, Sydney J. Peerless and Gary G. Ferguson

danger of cerebral ischemia and infarction after carotid occlusion has been greatly reduced by decreasing the risk of thromboembolism and by preoperative studies to determine the potential for collateral flow, which, if inadequate, can be supplemented by surgical arterial bypass. Thromboembolism has been reduced by performing abrupt rather than gradual occlusion of the proximal vessel and by doing so as close to the origin of the sac as possible to minimize the volume of the isolated segment and eliminate flow into it. Since 1978, the use of the detachable balloon

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Yoko Hirata, Noriyuki Sakata, Tooru Inoue, Kotaro Yasumori, Masahiro Yasaka and Yasushi Okada

-occlusion and high-grade stenosis groups except for hypertension, which was significantly more prevalent in the pseudoocclusion group (94.1%) than in the high-grade stenosis group (56.5%) (p = 0.008). There was no difference in the presence of peripheral arterial disease or ischemic heart disease between the groups. Although clinical presentation was similar, intergroup collateral flow patterns were significantly different (p = 0.047). Whereas an ACoAPCoA pattern developed more frequently in the pseudoocclusion group (41.2%) than in the high-grade stenosis group (13.0%), a

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Joseph C. Watson, Alexander M. Gorbach, Ryszard M. Pluta, Ramin Rak, John D. Heiss and Edward H. Oldfield

digital photographs. That procedure allowed for the analysis of temperature profiles of specified ROIs. Changes in temperature for each sequence of 100 infrared images were automatically extracted, plotted against time, and compared for different ROIs or selected pixels. In this manner, temperature data for specific arteries and areas of the cortical surface could be obtained. To detect subtle temperature changes in arteries and brain adjacent to the territory of occlusion (collateral flow), subtraction images were generated by subtracting the baseline image from an

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Ryuichi Kitani, Tooru Itouji, Yatsugi Noda, Makoto Kimura and Satoshi Uchida

internal elastic lamina of the arterial wall. The collapsed lumen of the middle cerebral artery (MCA) and internal carotid artery (ICA) induces cerebral infarction. 5, 8, 11, 22 Some patients escape massive cerebral infarction due to the mildness of MCA narrowing or collateral flow, 1, 27 suggesting the usefulness of early bypass surgery. We report the cases of two teenaged patients with dissecting aneurysms. One patient received a superficial temporal artery (STA)-MCA anastomosis, and his condition improved. The other patient was treated conservatively; he showed