CO2 reactivity in arteriovenous malformations of the brain: a transcranial Doppler ultrasound study

1994 ◽  
Vol 80 (4) ◽  
pp. 624-630 ◽  
Author(s):  
Antônio A F. De Salles ◽  
Iñaki Manchola
Keyword(s):  
Carbon Dioxide ◽  
Doppler Ultrasound ◽  
Transcranial Doppler ◽  
Arteriovenous Malformations ◽  
Transcranial Doppler Ultrasound ◽  
Content Type ◽  
Control Subjects ◽  
Feeding Vessels ◽  
Carbon Dioxide Reactivity ◽  
Fine Print

✓ Arteriovenous malformations (AVM's) are congenital tangles of vessels that have a high blood flow through a low-resistance nidus. The vessels in the nidus may lack normal vasoreactivity in response to changes in PaCO2 or perfusion pressure (autoregulation). Arteriovenous malformation hemodynamics have been assessed based on the response of AVM feeding arteries to hypocapnia. Twenty-five AVM patients, aged 34 ± 11 years (mean ± standard deviation), were admitted to the Massachusetts General Hospital for proton-beam radiation therapy. Fourteen healthy volunteers aged 30 ± 7 years served as control subjects. Angiograms with calibrated markers permitting magnification correction were available for all patients. The limits of the middle cerebral artery, as determined by transcranial Doppler ultrasonography, were compared to measurements made on the angiograms. Hyperventilation was induced at a rate set by a metronome. Fixed bilateral Doppler probes allowed almost simultaneous sampling of two vessels. Volunteer control subjects were hyperventilated in two steps. The two PaCO2 step decreases were significant (mean resting PaCO2 40.6 ± 3.5 mm Hg, Step 1 level 29.4 ± 3.5 mm Hg and Step 2 level 23.8 ± 3.5 mm Hg; p < 0.01). These decreases induced a significant decrease in mean flow velocity (Vm) and an increase in the pulsatility index (p < 0.001). Mean carbon dioxide reactivity (%ΔVm/ΔPaCO2) was 2.74 ± 1.0 for Step 1 and 1.44 ± 1.8 for Step 2 (p < 0.003). The mean PaCO2 decrease in patients was from 39.5 ± 4.0 mm Hg to 27.0 ± 3.5 mm Hg. Carbon dioxide reactivity was 0.92 ± 1.12 for feeding vessels and 2.59 ± 1.78 for nonfeeding vessels (p < 0.001). Transcranial Doppler ultrasound and angiographic depth measurements correlated well. Hyperventilation induced significantly more hemodynamic changes in control and nonfeeding middle cerebral arteries than in feeding vessels. Impaired CO2 reactivity may help to identify AVM feeding vessels as well as the relative magnitude of the flow provided to the malformation.

A randomized trial of nicardipine in subarachnoid hemorrhage: angiographic and transcranial Doppler ultrasound results

1993 ◽  
Vol 78 (4) ◽  
pp. 548-553 ◽  
Author(s):  
E. Clarke Haley ◽  
Neal F. Kassell ◽  
James C. Torner ◽  
_ _
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Doppler Ultrasound ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
High Dose ◽  
Content Type ◽  
Central Registry ◽  
Significant Difference ◽  
Fine Print ◽  
Flow Velocities

✓ Calcium antagonist drugs were proposed for use in patients with recent aneurysmal subarachnoid hemorrhage (SAH) because of their ability to block the effects of a wide variety of vasoconstrictor substances on cerebral arteries in vitro. It was suggested that these agents might, therefore, be useful in ameliorating cerebral vasospasm and its ischemic consequences which frequently complicate SAH. This hypothesis was tested in an arm of a randomized double-blind placebo-controlled trial of high-dose intravenous nicardipine in patients with recently ruptured aneurysms. Participating investigators were required to send selected copies of all admission and follow-up angiograms obtained between Days 7 and 11 following hemorrhage (the peak period of risk for vasospasm) to the Central Registry of the Cooperative Aneurysm Study for blinded interpretation and review for the presence and severity of angiographic vasospasm. In centers with transcranial Doppler ultrasound (TCD) capabilities, middle cerebral artery (MCA) mean flow velocities were measured and recorded. Angiograms obtained between Days 7 and 11 were available for 103 (23%) of 449 patients receiving nicardipine and 121 (26%) of 457 receiving placebo. There was a balance of prognostic factors for vasospasm between the groups. Fifty-one percent of placebo-treated patients had moderate or severe vasospasm on “Day 7–11 angiograms” compared to 33% of nicardipine-treated patients. This difference is statistically significant (p < 0.01). Sixty-seven (49%) of 137 placebo-treated patients examined with TCD between Days 7 and 11 had mean MCA flow velocities exceeding 120 cm/sec compared to 26 (23%) of 112 nicardipine-treated patients (significant difference, p < 0.001). These data suggest that high-dose intravenous nicardipine reduces the incidence and severity of delayed cerebral arterial narrowing in patients following aneurysmal SAH.

Posttraumatic cerebral arterial spasm: transcranial Doppler ultrasound, cerebral blood flow, and angiographic findings

1992 ◽  
Vol 77 (4) ◽  
pp. 575-583 ◽  
Author(s):  
Neil A. Martin ◽  
Curtis Doberstein ◽  
Cynthia Zane ◽  
Michael J. Caron ◽  
Kathleen Thomas ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Doppler Ultrasound ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Arterial Spasm ◽  
Content Type ◽  
Closed Head ◽  
Extracranial Ica ◽  
Fine Print

✓ Thirty patients admitted after suffering closed head injuries, with Glasgow Coma Scale scores ranging from 3 to 15, were evaluated with transcranial Doppler ultrasound monitoring. Blood flow velocity was determined in the middle cerebral artery (MCA) and the intracranial portion of the internal carotid artery (ICA) in all patients. Because proximal flow in the extracranial ICA declines in velocity when arterial narrowing becomes hemodynamically significant, the extracranial ICA velocity was concurrently monitored in 19 patients. To assess cerebral perfusion, cerebral blood flow (CBF) measurements obtained with the intravenous 113Xe technique were completed in 16 patients. Vasospasm, designated as MCA velocity exceeding 120 cm/sec, was found in eight patients (26.7%). Severe vasospasm, defined as MCA velocity greater than 200 cm/sec, occurred in three patients, and was confirmed by angiography in all three. Subarachnoid hemorrhage (SAH) was documented by computerized tomography in five (62.5%) of the eight patients with vasospasm. All cases of severe vasospasm were associated with subarachnoid blood. The time course of vasospasm in patients with traumatic SAH was similar to that found in patients with aneurysmal SAH; in contrast, arterial spasm not associated with SAH demonstrated an uncharacteristically short duration (mean 1.25 days), suggesting that this may be a different type of spasm. A significant correlation (p < 0.05) was identified between the lowest CBF and highest MCA velocity in patients during the period of vasospasm, indicating that arterial narrowing can lead to impaired CBF. Ischemic brain damage was found in one patient who had evidence of cerebral infarction in the territories supplied by the arteries affected by spasm. These findings demonstrate that delayed cerebral arterial spasm is a frequent complication of closed head injury and that the severity of spasm is, in some cases, comparable to that seen in aneurysmal SAH. This experience suggests that vasospasm is an important secondary posttraumatic insult that is potentially treatable.

Transcranial Doppler ultrasound study of the effects of nitrous oxide on cerebral autoregulation during neurosurgical anesthesia: a randomized controlled trial

2003 ◽  
Vol 99 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Domenico G. Iacopino ◽  
Alfredo Conti ◽  
Calogero Battaglia ◽  
Clotilde Siliotti ◽  
Tullio Lucanto ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Doppler Ultrasound ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Gas Mixture ◽  
Sevoflurane Anesthesia ◽  
Content Type ◽  
Randomized Controlled ◽  
Hyperemic Response ◽  
Fine Print

Object. Nitrous oxide has an adverse effect on cerebrovascular hemodynamics. Increased intracranial pressure, cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), and reduced autoregulation indices have been reported, but their magnitudes are still being debated. This study was designed to evaluate the effect of N2O on CBF and autoregulatory indexes during N2O—sevoflurane anesthesia in a prospective randomized controlled series of patients. Methods. Two groups of 20 patients were studied on the basis of the use of N2O in the anesthetic gas mixture. The transient hyperemic response test, which relies on transcranial Doppler ultrasound techniques, was used to assess cerebral hemodynamics. The time-averaged mean flow velocity, considered to be an index of actual CBF, increased significantly (p < 0.001) after introduction of N2O. The hyperemic response, considered as the index of autoregulatory potential, decreased significantly after introduction of N2O into the gas mixture (p < 0.001). Conclusions. The increase in CBF and the reduction in autoregulatory indices suggest caution in using N2O during sevoflurane anesthesia, especially in patients with reduced autoregulatory reserve and during neurosurgical interventions. Transcranial Doppler ultrasonography is an efficacious method to evaluate the effects of anesthetic agents on CBF.

Clinical significance of pedicle aneurysms on feeding vessels, especially those located in infratentorial arteriovenous malformations

2000 ◽  
Vol 92 (6) ◽  
pp. 995-1001 ◽  
Author(s):  
Manfred Westphal ◽  
Ulrich Grzyska
Keyword(s):  
Arteriovenous Malformations ◽  
Endovascular Techniques ◽  
Treatment Procedure ◽  
Major Hemorrhage ◽  
Content Type ◽  
Ruptured Aneurysms ◽  
Aggressive Management ◽  
Feeding Vessels ◽  
Fine Print ◽  
Feeding Vessel

Object. The diminishing threshold for the application of neuroimaging leads to an increasingly frequent diagnosis of previously asymptomatic arteriovenous malformations (AVMs). In such a context, it is warranted to define the criteria that make a lesion potentially hazardous so that neurosurgeons and patients reach a decision concerning how to manage the AVM. In addition to the proposed grading system for AVMs, which assesses the risk of an actual treatment procedure, several studies have been concerned with the evaluation of angioarchitectural features. The goal of the present study is to demonstrate the significance of feeding vessel pedicle aneurysms, especially those found in infratentorial AVMs.Methods. To determine the incidence of associated aneurysms, the authors reviewed an unselected cohort of 242 consecutive patients with AVMs managed between 1989 and 1999. Within this group were 240 patients who were treated by surgery, endovascular techniques, or a combination of both. Of these patients, 216 harbored a supratentorial and 24 an infratentorial AVM. Two additional patients with supratentorial AVMs underwent treatment of ruptured aneurysms without treatment of the AVMs. In six of the patients with supratentorial AVMs, proximal flow-related aneurysms were found on major feeding arteries, only one of which had caused hemorrhage. In only one patient were there additional distal feeding vessel pedicle aneurysms near the AVM, one of which had caused a major hemorrhage. In contrast, four of 24 patients with infratentorial AVMs had distal feeding artery pedicle aneurysms. Three of these aneurysms had caused hemorrhage.Conclusions. Pedicle aneurysms on feeding vessels are frequently associated with hemorrhage (four of five cases in this series). In our cohort of 242 treated patients (240 treated for AVM and two for an aneurysm), feeding vessel pedicle aneurysms appear to occur more frequently in conjunction with infratentorial AVMs, which justifies aggressive management to prevent incidences of morbidity associated with rupture of the aneurysm.

Transcranial Doppler ultrasound studies of cerebral autoregulation and subarachnoid hemorrhage in the rabbit

1990 ◽  
Vol 73 (4) ◽  
pp. 601-610 ◽  
Author(s):  
Richard J. Nelson ◽  
Sheila Perry ◽  
Tony K. Hames ◽  
John D. Pickard
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Flow Velocity ◽  
Doppler Ultrasound ◽  
Transcranial Doppler ◽  
Cerebral Autoregulation ◽  
Time Course ◽  
Cerebrovascular Reactivity ◽  
Waveform Analysis ◽  
Content Type ◽  
Fine Print

✓ The authors describe a method for Doppler ultrasound recording of flow velocity in the basilar artery of normal rabbits and rabbits with experimental subarachnoid hemorrhage (SAH). With this transcranial Doppler (TCD) model, clinical assumptions regarding flow velocity/cerebral blood flow (CBF) relationships, autoregulatory responses, and Doppler spectral waveform analysis can be tested under controlled conditions and compared with established methods of CBF measurement (hydrogen clearance). The time course of changes in flow velocity following SAH (cerebral vasospasm) is successfully demonstrated using the experimental TCD method. There are significant differences in the flow velocity and CBF responses to hypercapnia, hypocapnia, and trimethaphan-induced hypotension which indicate that TCD cannot be considered a simple alternative to CBF measurement for the study of cerebrovascular reactivity and cerebral autoregulation.

Dural arteriovenous malformations

1974 ◽  
Vol 40 (3) ◽  
pp. 322-329 ◽  
Author(s):  
Edward J. Kosnik ◽  
William E. Hunt ◽  
Carole A. Miller
Keyword(s):  
Surgical Treatment ◽  
Arteriovenous Malformations ◽  
Content Type ◽  
Venous Sinuses ◽  
Feeding Vessels ◽  
Physical Findings ◽  
Fine Print

✓ The history, physical findings, and treatment of dural arteriovenous malformations are reviewed. The importance of completely identifying and obliterating the fistula, even at the expense of obliterating major venous sinuses, is emphasized. Failure of surgical treatment usually is the result of mistaking the more obvious dilated feeding vessels for the lesion itself.

Arteriovenous malformations of the brain: choosing embolic materials to enhance safety and ease of excision

1992 ◽  
Vol 77 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Phillip D. Purdy ◽  
H. Hunt Batjer ◽  
Richard C. Risser ◽  
Duke Samson
Keyword(s):  
Arteriovenous Malformations ◽  
Arterial Occlusion ◽  
Technical Difficulty ◽  
Content Type ◽  
Feeding Vessels ◽  
Embolic Materials ◽  
Materials Used ◽  
Proximal Occlusion ◽  
Distal Occlusion ◽  
Fine Print

✓ The authors report their experience with surgical resection of 108 previously embolized arteriovenous malformations (AVM's). Embolization was performed via only transfemoral catheterization in 70 lesions and via the surgical exposure of feeding vessels in 32. The remaining six patients were referred for resection following silicone sphere embolization elsewhere. Materials used included polyvinyl alcohol (PVA) foam, platinum microcoils, detachable silicone balloons, surgical silk, a mixture of 33% ethanol and microfibrillar collagen, and isobutyl cyanoacrylate (IBCA). It is believed that proximal arterial occlusion with balloons is an inferior choice for preresection embolization, because the technical difficulty of placement is high and the nidus of the AVM is unaffected. Vascular coagulation and section and AVM retraction are more difficult with IBCA; therefore, this is also considered an inferior choice. Among the materials studied, the combination of PVA for distal occlusion and microcoils for proximal occlusion appears to be the superior choice. Fewer complications (stroke or hemorrhage) are seen when intraarterial Amytal (amobarbital) testing is used to guide the embolization. Data regarding toxicity, oncogenicity, and vascular metabolism or recanalization associated with PVA, IBCA, and n-butyl cyanoacrylate are reviewed.

Transcranial Doppler ultrasound findings in cerebral venous sinus thrombosis

1994 ◽  
Vol 80 (2) ◽  
pp. 332-335 ◽  
Author(s):  
Joanna M. Wardlaw ◽  
G. T. Vaughan ◽  
A. James W. Steers ◽  
Robin J. Sellar
Keyword(s):  
Doppler Ultrasound ◽  
Transcranial Doppler ◽  
Sinus Thrombosis ◽  
Transcranial Doppler Ultrasound ◽  
Cerebral Venous Sinus Thrombosis ◽  
Venous Sinus ◽  
Content Type ◽  
Venous Sinus Thrombosis ◽  
Acute Thrombosis ◽  
Ultrasound Findings

✓ Transcranial Doppler ultrasound (TCD) findings are described in a patient with acute thrombosis of the sagittal venous sinus. The TCD finding of prominent venous signals adjacent to the middle cerebral artery gave the first indication of the diagnosis, which was subsequently confirmed by computerized tomography. Awareness of the possible TCD findings in patients with a similar history may lead to a more rapid diagnosis of cerebral venous sinus thrombosis.

Validation of transcranial Doppler ultrasound with a stereotactic neurosurgical technique

1995 ◽  
Vol 82 (6) ◽  
pp. 972-975 ◽  
Author(s):  
Lee H. Monsein ◽  
Alex Y. Razumovsky ◽  
Stacey J. Ackerman ◽  
Haring J. W. Nauta ◽  
Daniel F. Hanley
Keyword(s):  
Cerebral Artery ◽  
Transcranial Doppler ◽  
Anterior Cerebral Artery ◽  
Transcranial Doppler Ultrasound ◽  
Content Type ◽  
Stereotactic Technique ◽  
Significant Difference ◽  
Neurosurgical Technique ◽  
The Individual ◽  
Fine Print

✓ Vessel identification during a transcranial Doppler (TCD) ultrasound examination is usually based on well-established inferential criteria without confirmation by imaging. Part of a routine study involves taking measurements from the M1 segment of the middle cerebral artery (MCA) and the A1 segment of the anterior cerebral artery (ACA) at the points of maximum mean linear blood flow velocity (LBFV). The authors tested the hypothesis that insonation is from the midpoints of the M1 and A1 segments during clinical TCD examinations. Conventional hand-held TCD examinations were performed on five volunteers. The points of maximum mean LBFV of the M1 and A1 segments of the MCA and ACA were located. Measurements were also taken from the midpoints of the M1 and A1 segments using a magnetic resonance (MR) imaging-guided stereotactic TCD technique. Values for depths of insonation and maximum mean LBFV obtained with the two techniques were compared. There was no significant difference between the two techniques for the measured values of depth of insonation of either the individual vessels (p > 0.11) or the aggregate (p = 0.46). There was a significant difference between the aggregate maximum mean LBFV measurements (p = 0.0022). The hand-held technique systematically produced higher maximum mean LBFV than the MR-guided stereotactic technique. The authors conclude that when using traditional criteria for TCD examination of the ACA and MCA, the points of insonation approximate the middle of the A1 and M1 segments.

Prediction of tolerance to carotid artery occlusion using transcranial Doppler ultrasound

1994 ◽  
Vol 81 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Cole A. Giller ◽  
Dana Mathews ◽  
Brandy Walker ◽  
Philip Purdy ◽  
Angie M. Roseland
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Balloon Occlusion ◽  
Content Type ◽  
Carotid Artery Compression ◽  
Fine Print

✓ Surgical sacrifice of the carotid artery is a frequently anticipated event during the treatment of certain aneurysms and tumors. The ability to predict tolerance to carotid artery occlusion is therefore of benefit when planning procedures in which the carotid artery is at risk. A trial of carotid artery occlusion using an angiographic balloon during concurrent neurological examination or blood flow studies is an accepted method for testing tolerance, but it carries the risks of an angiogram and cannot be performed at the bedside. Transcranial Doppler ultrasound (TCD) is a noninvasive modality that permits measurement of blood velocity in cerebral vessels. The immediate effects of carotid artery occlusion on middle cerebral artery (MCA) perfusion can be obtained by insonating this artery during manual carotid artery compression. To compare the TCD response to carotid artery compression with the data obtained with more formal testing, the MCA of 22 patients was insonated during manual carotid artery compression and the results compared with the clinical tolerance to balloon occlusion in all patients and to blood flow studied by single photon emission computerized tomography before or during balloon occlusion in 14 of the 22 patients. Surgery was planned to treat giant unruptured aneurysms in 17 cases, intracranial tumors in three, a carotid-cavernous fistula in one, and a carotid artery injury in one. Fifteen patients showed a reduction in TCD flow velocities by no more than 65%; of these, 14 (93%) clinically tolerated the balloon occlusion test. Of the seven patients showing a TCD flow velocity decrease of more than 65%, six (86%) developed a transient focal deficit during the occlusion. It is concluded that the change in MCA velocity measured with TCD studies during manual carotid artery occlusion is a useful predictor of the clinical and blood flow responses to a trial of carotid artery occlusion with an angiographic balloon.

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