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Helge Nornes, Arne Grip and Per Wikeby

✓ The use of a pulsed echo Doppler technique during procedures for occlusion of intracranial aneurysms is described. Saccular aneurysms can be located with reference to probe position and depth setting. Tracings of intra-aneurysmal flow are presented, and the characteristic flow pattern is discussed. Special emphasis has been placed on the parent artery flow, particularly the effect of lumen reduction on flow velocity. Results of flow velocity studies on the cognate (direct) and collateral flow in the middle cerebral artery and the proximal anterior cerebral artery are presented and discussed.

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Rune Aaslid, Thomas-Marc Markwalder and Helge Nornes

✓ In this report the authors describe a noninvasive transcranial method of determining the flow velocities in the basal cerebral arteries. Placement of the probe of a range-gated ultrasound Doppler instrument in the temporal area just above the zygomatic arch allowed the velocities in the middle cerebral artery (MCA) to be determined from the Doppler signals. The flow velocities in the proximal anterior (ACA) and posterior (PCA) cerebral arteries were also recorded at steady state and during test compression of the common carotid arteries. An investigation of 50 healthy subjects by this transcranial Doppler method revealed that the velocity in the MCA, ACA, and PCA was 62 ± 12, 51 ± 12, and 44 ± 11 cm/sec, respectively. This method is of particular value for the detection of vasospasm following subarachnoid hemorrhage and for evaluating the cerebral circulation in occlusive disease of the carotid and vertebral arteries.

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Bertil Romner, Bengt Ljunggren, Lennart Brandt and Hans Saveland

, Rautenberg W , Sitzer G , et al : Transcranial Doppler ultrasound for the assessment of intracranial arterial flow velocity — Part 1. Examination technique and normal values. Surg Neurol 27 : 439 – 448 , 1987 Hennerici M, Rautenberg W, Sitzer G, et al: Transcranial Doppler ultrasound for the assessment of intracranial arterial flow velocity — Part 1. Examination technique and normal values. Surg Neurol 27: 439–448, 1987 14. Hillman J , von Essen C , Leszniewski W , et al : Significance of “ultra

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Joanna M. Wardlaw, G. T. Vaughan, A. James W. Steers and Robin J. Sellar

admission, showed no definite abnormality. A lumbar puncture revealed mildly blood-stained cerebrospinal fluid (CSF) and the pressure was elevated (36.5 cm H 2 O). ATCD examination using a 2-MHz probe showed normal arterial flow velocity signals from the middle, anterior, and posterior cerebral arteries, 1 but prominent, high-amplitude venous signals were detected adjacent to both middle cerebral arteries ( Fig. 1 ). As venous signals have almost never been observed near the middle cerebral arteries in our experience, the possibility was raised of a cerebral venous sinus

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Minesh P. Mehta, Daniel Petereit, Patrick Turski, Mark Gehring, Allan Levin and Timothy Kinsella

velocity encodings. A single velocity-encoding 2-D phase-contrast angiogram can be obtained in about 1 to 3 minutes; multiple velocity-encoding 2-D phase-contrast angiograms provide information about both the AVM nidus (arterial) flow velocity and venous anatomy. High-velocity fistulas can occasionally be identified by encoding at high velocities. Flow direction can also be determined using phase images generated from the phase-contrast angiography data set. When obtained as a thick slab projection, 2-D phase-contrast angiograms can be used to determine flow

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Antônio A F. De Salles and Iñaki Manchola

Hassler W, Steinmetz H, Gawlowski J: Transcranial Doppler ultrasonography in raised intracranial pressure and in intracranial circulatory arrest. J Neurosurg 68: 745–751, 1988 17. Hennerici M , Rautenberg W , Sitzer G , et al : Transcranial Doppler ultrasound for the assessment of intracranial arterial flow velocity — Part 1. Examination technique and normal values. Surg Neurol 27 : 439 – 448 , 1987 Hennerici M, Rautenberg W, Sitzer G, et al: Transcranial Doppler ultrasound for the assessment of intracranial arterial

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Cole A. Giller, Kurt Hodges and H. Hunt Batjer

: Directional arterial flow velocity: a sensitive index of changes in a peripheral vascular resistance. Surgery 79 : 350 – 355 , 1976 Rittenhouse EA, Maixner W, Burr JW, et al: Directional arterial flow velocity: a sensitive index of changes in a peripheral vascular resistance. Surgery 79: 350–355, 1976 31. Ropper AH , Kehne SM , Wechsler L : Transcranial Doppler in brain death. Neurology 37 : 1733 – 1735 , 1987 Ropper AH, Kehne SM, Wechsler L: Transcranial Doppler in brain death. Neurology 37: 1733–1735, 1987

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Donald G. Ghosset, John Straiton, Isobel McDonald, Muriel Cockburn and Ross Bullock

may be several reasons for this. Vasospasm in peripheral cortical vessels may not be detected by TCD. 1, 23, 26, 27, 29 Global reduct;ons in cerebral blood flow (CBF) 19 and/or loss of cerebral autoregulation 30 may induce changes in arterial flow velocity, independent of changes caused by vasospasm. The MCA:ICA index corrects for volume flow, 17 but we did not find this index useful in predicting delayed neurological deficit. This may be because a major reduction in CBF develops suddenly, as a late feature, after autoregulatory compensation has been exhausted

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Martin Schöoning, Reiner Buchholz and Jochen Walter

Doppler ultrasound for the assessment of intracranial arterial flow velocity — part 1. Examination technique and normal values. Surg Neurol 27 : 439 – 448 , 1987 Hennerici M, Rautenberg W, Sitzer G, et al: Transcranial Doppler ultrasound for the assessment of intracranial arterial flow velocity — part 1. Examination technique and normal values. Surg Neurol 27: 439–448, 1987 19. Markwalder TM , Grolimund P , Seiler RW , et al : Dependency of blood flow velocity in the middle cerebral artery on end-tidal carbon dioxide

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Mark S. Dias, Michele L. Shaffer, Mark R. Iantosca and Kenneth L. Hill Jr.

: Pediatric Neuroimaging ed 2 New York , Raven Press , 1995 3 Bowman RM , McLone DG , Grant JA , Tomita T , Ito JA : Spina bifida outcome: a 25-year prospective . Pediatr Neurosurg 34 : 114 – 120 , 2001 4 Del Bigio MR : Pathophysiologic consequences of hydrocephalus . Neurosurg Clin N Am 12 : 639 – 649 , vii , 2001 5 Goh D , Minns RA : Intracranial pressure and cerebral arterial flow velocity indices in childhood hydrocephalus: current review . Childs Nerv Syst 11 : 392 – 396 , 1995 6 Grant C , Iddon J , Talbot E