scholarly journals An analysis of transcranial doppler to interpret changes in cerebral circulation under +Gz

2020 ◽  
Vol 63 ◽  
pp. 61-64
Author(s):  
S Dinakar ◽  
A Agarwal
Keyword(s):  
Transcranial Doppler ◽  
High Performance ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Technical Difficulty ◽  
Adult Males ◽  
Non Invasive ◽  
Gradual Onset ◽  
Light Loss ◽  
Rate Profile

Introduction: The use of Transcranial Doppler (TCD) to measure the cerebral blood flow velocity (BFV) is one of the most elusive tasks under +Gz. The reason for this is the technical difficulty in keeping the TCD fixed during acceleration. There is no conclusive principle of the behavior of cerebral blood vessels under +Gz, despite earlier attempts in animal/human studies. In our study, we were able to overcome the technical difficulty and record the cerebral BFV of the middle cerebral artery under +Gz. Material and Methods: Twenty healthy adult males consented to participate in the study. High-performance human centrifuge was used to subject them to +Gz acceleration. The participants were instrumented with electrocardiography, thermistor bead, oxygen saturation probe, non-invasive blood pressure and TCD probe. Relaxed peripheral light loss (PLL) and straining PLL were recorded in a single gradual-onset rate profile. Results: The TCD data were retrieved and the data was plotted. The Doppler waveform varied with a change in +Gz. Pulsatility (Gosling) index was derived. The index increases as Gz level builds up, indicating an increase in arterial resistance. This increase was statistically significant. Conclusion: The understanding, so far, has been based on a presumption of vasoconstriction in the cerebral arteries. However, when monitoring TCD against increasing +Gz, it is not the presence or absence of the waveform that is of significance; however, it is the change in the pattern of the waveform that is noteworthy.

scholarly journals Transcranial Doppler Evaluation of the Cerebral Vasculature in Women Patients who Have Migraine with Aura

Pain Medicine ◽  
2020 ◽  
Vol 21 (11) ◽  
pp. 3012-3017
Author(s):  
Igor Petrušić ◽  
Ana Podgorac ◽  
Aleksandra Radojičić ◽  
Jasna Zidverc-Trajković
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Migraine With Aura ◽  
Transcranial Doppler ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Sonography ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Left And Right

Abstract Background Previous studies suggest that increased cerebrovascular reactivity might be a feature of patients who have migraine with aura (MwA). The correlation between the clinical presentation of migraine with aura and transcranial Doppler parameters remains unclear. Objective The main aim of this study was to explore cerebral blood flow, vascular resistance, and cerebrovascular reactivity in women MwA. Also, the relationships between hemodynamic conditions and aura characteristics are examined. Design Cross-sectional study. Setting Headache Center, Neurology Clinic, Clinical Center of Serbia. Subjects Fifty-four women MwA and 49 healthy controls (HCs). Methods Transcranial Doppler sonography examination was used to determine blood flow mean velocity (MV) and pulsatility index (PI), as well as breath-holding index (BHI), in 15 arterial segments comprising the circle of Willis. Results A total of 54 women MwA and 49 HCs were studied. The PIs of all segments of the left and right middle cerebral arteries and the left and right anterior cerebral arteries were significantly higher in MwA with regards to HCs. Also, both the left and right BHIs were significantly higher in MwA than HCs. In addition, MVs of the right vertebral artery and the first segment of the basilar artery were significantly lower in MwA than HCs. Longer duration of migraine aura showed a weak negative correlation with the PI of the left posterior cerebral artery. Conclusions Our findings suggest increased vessel pulsatility, abnormal cerebrovascular reactivity, and decreased cerebral blood flow velocity in several arterial segments of the Willis circle in women MwA.

Cerebral hemodynamics in schizophrenia during the Trail Making Test: A functional transcranial Doppler sonography study

2016 ◽  
Vol 33 (S1) ◽  
pp. S107-S107 ◽  
Author(s):  
D. Schuepbach ◽  
S. Egger ◽  
S.C. Herpertz
Keyword(s):  
Transcranial Doppler ◽  
Negative Symptoms ◽  
Doppler Sonography ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Sonography ◽  
Cerebral Hemodynamics ◽  
Trail Making Test ◽  
Trail Making ◽  
Functional Transcranial Doppler Sonography

IntroductionSchizophrenia is a severe mental disorder, with complex symptoms involving psychosis, negative symptoms and cognitive impairment. The Trail Making Test (TMT) has been widely used to assess attention and executive function. Functional transcranial Doppler sonography (fTCD) of basal cerebral arteries allows monitoring of aberrant cerebral hemodynamics during cognitive tasks in this patient group.ObjectivesWe assessed cerebral hemodynamics in the middle cerebral arteries (MCA) using fTCD while patients with schizophrenia and healthy subjects performed the TMT and a control task.MethodsFifteen patients with chronic schizophrenia and 15 healthy controls performed the TMT-A and -B during fTCD measurements of the MCA. Dependent measures were performance, mean cerebral blood flow velocity (MFV) and the lateralization.ResultsPatients demonstrated an overall decreased speed of solution (P = 0.002), and there was no significant effect of age. They showed a significantly increased flow pattern for the TMT-B (P = 0.005). There were no lateralization differences between diagnostic groups.ConclusionsThere was a performance deficit in patients with schizophrenia for both TMT-A and -B that fits well with results of existing literature. The aberrant hemodynamic response supports the idea that cognitive performance elicits an aberrant cerebral hemodynamic correlate. It adds to the notion that fTCD is a valuable tool to correlate psychological paradigms with brain perfusion in patients with schizophrenia.Disclosure of interestThe authors have not supplied their declaration of competing interest.

scholarly journals Transcranial Doppler Ultrasound: A Review of the Physical Principles and Major Applications in Critical Care

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Jawad Naqvi ◽  
Kok Hooi Yap ◽  
Gulraiz Ahmad ◽  
Jonathan Ghosh
Keyword(s):  
Transcranial Doppler ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Low Frequency ◽  
Transcranial Doppler Ultrasound ◽  
Arterial Stenosis ◽  
Dynamic Monitoring ◽  
High Temporal Resolution ◽  
Thin Bone ◽  
Cerebral Microembolism

Transcranial Doppler (TCD) is a noninvasive ultrasound (US) study used to measure cerebral blood flow velocity (CBF-V) in the major intracranial arteries. It involves use of low-frequency (≤2 MHz) US waves to insonate the basal cerebral arteries through relatively thin bone windows. TCD allows dynamic monitoring of CBF-V and vessel pulsatility, with a high temporal resolution. It is relatively inexpensive, repeatable, and portable. However, the performance of TCD is highly operator dependent and can be difficult, with approximately 10–20% of patients having inadequate transtemporal acoustic windows. Current applications of TCD include vasospasm in sickle cell disease, subarachnoid haemorrhage (SAH), and intra- and extracranial arterial stenosis and occlusion. TCD is also used in brain stem death, head injury, raised intracranial pressure (ICP), intraoperative monitoring, cerebral microembolism, and autoregulatory testing.

scholarly journals Toward Automated Classification of Pathological Transcranial Doppler Waveform Morphology via Spectral Clustering

2019 ◽  
Author(s):  
Samuel G. Thorpe ◽  
Corey M. Thibeault ◽  
Nicolas Canac ◽  
Kian Jalaleddini ◽  
Amber Dorn ◽  
...  
Keyword(s):  
Transcranial Doppler ◽  
Spectral Clustering ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Morphological Variability ◽  
Three Dimensional ◽  
Subjective Assessment ◽  
Cluster Number ◽  
Vessel Occlusion ◽  
Gap Statistic

AbstractCerebral Blood Flow Velocity waveforms acquired via Transcranial Doppler (TCD) can provide evidence for cerebrovascular occlusion and stenosis. Thrombolysis in Brain Ischemia (TIBI) flow grades are widely used for this purpose, but require subjective assessment by expert evaluators to be reliable. In this work we seek to determine whether TCD morphology can be objectively assessed using an unsupervised machine learning approach to waveform categorization. TCD beat waveforms were recorded at multiple depths from the Middle Cerebral Arteries of 106 subjects; 33 with CTA-confirmed Large Vessel Occlusion (LVO). From each waveform, three morphological variables were extracted, quantifying absolute peak onset, number/prominence of auxiliary peaks, and systolic canopy length. Spectral clustering identified groups implicit in the resultant three-dimensional feature space, with gap-statistic criteria establishing the optimal cluster number. We found that gap-statistic disparity was maximized at four clusters, referred to as flow types I, II, III, and IV. Types I and II were primarily composed of control subject waveforms, whereas types III and IV derived mainly from LVO patients. Cluster morphologies for types I and IV aligned clearly with Normal and Blunted TIBI flows, respectively. Types II and III represented commonly observed flow-types not delineated by TIBI, which nonetheless deviate quantifiably from normal and blunted flows. We conclude that important morphological variability exists beyond that currently quantified by TIBI in populations experiencing or at-risk for acute ischemic stroke, and posit that the observed flow-types provide the foundation for objective methods of real-time automated flow type classification.

Cerebrovascular Response to Repetitive Visual Stimulation in Interictal Migraine with Aura

Cephalalgia ◽  
2004 ◽  
Vol 24 (9) ◽  
pp. 700-706 ◽  
Author(s):  
K Nedeltchev ◽  
M Arnold ◽  
M Schwerzmann ◽  
A Nirkko ◽  
F Lagger ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transcranial Doppler ◽  
Blood Flow Velocity ◽  
Visual Stimulation ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Ultrasound ◽  
Healthy Controls ◽  
Cerebral Vasoreactivity

Cortical hypersensitivity and absent habituation to different stimuli have been observed in migraine patients. These features might also be transmitted to the cerebral vasoreactivity, but results are conflicting so far. Transcranial Doppler ultrasound (TCD) was used to assess cerebral blood flow velocity (CBFV) changes in the middle (MCA) and posterior cerebral arteries (PCA) in relation to repetitive checkerboard visual stimulation. Stimulation consisted of 10 consecutive cycles, each comprising 10 s stimulation and 10 s rest. TCD recordings were analysed using stimulus-related averaging algorithm. Data of 19 interictal migraineurs with aura were compared to those of 19 headache-free healthy volunteers. The CBFV increase in PCA and in MCA during visual stimulation was significantly larger and steeper in migraineurs than in controls ( P = 0.017 and P = 0.005). The response in PCA remained stable over the 10 stimulation cycles, both in migraineurs and in controls. The response in MCA was stable only in migraineurs. In controls it decreased over the last 5 stimulation cycles compared with the first 5 cycles ( P = 0.04). Migraineurs with aura exhibit a larger cerebrovascular response to repetitive visual stimulation compared to headache-free subjects. A reduced adaptation to environmental stimuli in migraine is suggested, since there was no habituation in migraineurs in contrast to healthy controls.

scholarly journals Association of transcranial Doppler blood flow velocity slow waves with delayed cerebral ischemia in patients suffering from subarachnoid hemorrhage: a retrospective study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Vasilios E. Papaioannou ◽  
Karol P. Budohoski ◽  
Michal M. Placek ◽  
Zofia Czosnyka ◽  
Peter Smielewski ◽  
...  
Keyword(s):  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Flow Velocity ◽  
Transcranial Doppler ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Delayed Cerebral Ischemia ◽  
Area Under The Curve ◽  
Slow Waves

Abstract Background Cerebral vasospasm (VS) and delayed cerebral ischemia (DCI) constitute major complications following subarachnoid hemorrhage (SAH). A few studies have examined the relationship between different indices of cerebrovascular dynamics with the occurrence of VS. However, their potential association with the development of DCI remains elusive. In this study, we investigated the pattern of changes of different transcranial Doppler (TCD)-derived indices of cerebrovascular dynamics during vasospasm in patients suffering from subarachnoid hemorrhage, dichotomized by the presence of delayed cerebral ischemia. Methods A retrospective analysis was performed using recordings from 32 SAH patients, diagnosed with VS. Patients were divided in two groups, depending on development of DCI. Magnitude of slow waves (SWs) of cerebral blood flow velocity (CBFV) was measured. Cerebral autoregulation was estimated using the moving correlation coefficient Mxa. Cerebral arterial time constant (tau) was expressed as the product of resistance and compliance. Complexity of CBFV was estimated through measurement of sample entropy (SampEn). Results In the whole population (N = 32), magnitude of SWs of ipsilateral to VS side CBFV was higher during vasospasm (4.15 ± 1.55 vs before: 2.86 ± 1.21 cm/s, p < 0.001). Ipsilateral SWs of CBFV before VS had higher magnitude in DCI group (N = 19, p < 0.001) and were strongly predictive of DCI, with area under the curve (AUC) = 0.745 (p = 0.02). Vasospasm caused a non-significant shortening of ipsilateral values of tau and increase in SampEn in all patients related to pre-VS measurements, as well as an insignificant increase of Mxa in DCI related to non-DCI group (N = 13). Conclusions In patients suffering from subarachnoid hemorrhage, TCD-detected VS was associated with higher ipsilateral CBFV SWs, related to pre-VS measurements. Higher CBFV SWs before VS were significantly predictive of delayed cerebral ischemia.

scholarly journals Cerebral Hemodynamics and Intracranial Compliance Impairment in Critically Ill COVID-19 Patients: A Pilot Study

2021 ◽  
Vol 11 (7) ◽  
pp. 874
Author(s):  
Sérgio Brasil ◽  
Fabio Silvio Taccone ◽  
Sâmia Yasin Wahys ◽  
Bruno Martins Tomazini ◽  
Filippo Annoni ◽  
...  
Keyword(s):  
Critically Ill ◽  
Cerebral Arteries ◽  
Receiver Operating Curve ◽  
Severe Illness ◽  
Mean Flow ◽  
Non Invasive ◽  
Intracranial Compliance ◽  
Middle Cerebral Arteries ◽  
Primary Composite Outcome ◽  
Cerebrovascular Hemodynamics

Introduction: One of the possible mechanisms by which the new coronavirus (SARS-Cov2) could induce brain damage is the impairment of cerebrovascular hemodynamics (CVH) and intracranial compliance (ICC) due to the elevation of intracranial pressure (ICP). The main objective of this study was to assess the presence of CVH and ICC alterations in patients with COVID-19 and evaluate their association with short-term clinical outcomes. Methods: Fifty consecutive critically ill COVID-19 patients were studied with transcranial Doppler (TCD) and non-invasive monitoring of ICC. Subjects were included upon ICU admission; CVH was evaluated using mean flow velocities in the middle cerebral arteries (mCBFV), pulsatility index (PI), and estimated cerebral perfusion pressure (eCPP), while ICC was assessed by using the P2/P1 ratio of the non-invasive ICP curve. A CVH/ICC score was computed using all these variables. The primary composite outcome was unsuccessful in weaning from respiratory support or death on day 7 (defined as UO). Results: At the first assessment (n = 50), only the P2/P1 ratio (median 1.20 [IQRs 1.00–1.28] vs. 1.00 [0.88–1.16]; p = 0.03) and eICP (14 [11–25] vs. 11 [7–15] mmHg; p = 0.01) were significantly higher among patients with an unfavorable outcome (UO) than others. Patients with UO had a significantly higher CVH/ICC score (9 [8–12] vs. 6 [5–7]; p < 0.001) than those with a favorable outcome; the area under the receiver operating curve (AUROC) for CVH/ICC score to predict UO was 0.86 (95% CIs 0.75–0.97); a score > 8.5 had 63 (46–77)% sensitivity and 87 (62–97)% specificity to predict UO. For those patients undergoing a second assessment (n = 29), after a median of 11 (5–31) days, all measured variables were similar between the two time-points. No differences in the measured variables between ICU non-survivors (n = 30) and survivors were observed. Conclusions: ICC impairment and CVH disturbances are often present in COVID-19 severe illness and could accurately predict an early poor outcome.

Carotid-Cavernous Fistula Treated with Detachable Balloon during Bilateral Transcranial Doppler Monitoring of Middle Cerebral Arteries

1992 ◽  
Vol 33 (2) ◽  
pp. 145-148 ◽  
Author(s):  
P. H. Nakstad ◽  
J. K. Hald ◽  
W. Sorteberg
Keyword(s):  
Carotid Artery ◽  
Transcranial Doppler ◽  
Cerebral Arteries ◽  
Carotid Cavernous Fistula ◽  
Detachable Balloon ◽  
Cavernous Fistula ◽  
Doppler Technique ◽  
Middle Cerebral Arteries

A traumatic carotid-cavernous fistula was closed with a silicone detachable balloon. Prior to the closure of the fistula, clinical and transcranial Doppler testing was performed in order to evaluate the consequences of a possible occlusion of the carotid artery. A newly developed Doppler technique with bilateral simultaneous velocity recordings of the middle cerebral arteries was useful during the procedure. The detachable balloon was effective in closing the fistula, but collapse of the balloon and the development of an extradural aneurysm was found at control examinations.

Functional Coatings for Damage Detection in Aerospace Structures

2021 ◽  
Vol 22 (1) ◽  
pp. 95-103
Author(s):  
Agathe Demay ◽  
Johnathan Hernandez ◽  
Perla Latorre ◽  
Remelisa Esteves ◽  
Seetha Raghavan
Keyword(s):  
Damage Detection ◽  
High Performance ◽  
Structural Integrity ◽  
Alumina Nanoparticles ◽  
Functional Coatings ◽  
Aerospace Structures ◽  
Non Invasive ◽  
Damage Sensing ◽  
Composite Substrate ◽  
Open Hole

The future of aerospace structures is highly dependent on the advancement of reliable and high-performance materials, such as composite materials and metals. Innovation in high resolution non-invasive evaluation of these materials is needed for their qualification and monitoring for structural integrity. Aluminum oxide (or α-alumina) nanoparticles present photoluminescent properties that allow stress and damage sensing via photoluminescence piezospectroscopy. This work describes how these nanoparticles are added into a polymer matrix to create functional coatings that monitor the damage of the underlying composite or metallic substrates. Different volume fractions of α-alumina nanoparticles in the piezospectroscopic coatings were studied for determining the sensitivity of the coatings and successful damage detection was demonstrated for an open-hole tension composite substrate as well as 2024 aluminum tensile substrates with a subsurface notch.

Sign in / Sign up

Export Citation Format

Share Document