Transcranial Color-coded Doppler Research Articles

The Diagnostic Accuracy of Transcranial Color-Coded Doppler Ultrasound Technique in Stratifying Intracranial Cerebral Artery Stenoses in Cerebrovascular Disease Patients: A Systematic Review and Meta-Analysis.

The early and accurate stratification of intracranial cerebral artery stenosis (ICAS) is critical to inform treatment management and enhance the prognostic outcomes in patients with cerebrovascular disease (CVD). Digital subtraction angiography (DSA) is an invasive and expensive procedure but is the gold standard for the diagnosis of ICAS. Over recent years, transcranial color-coded Doppler ultrasound (TCCD) has been suggested to be a useful imaging method for accurately diagnosing ICAS. However, the diagnostic accuracy of TCCD in stratifying ICASs among patients with CVD remains unclear. Therefore, this systematic review and meta-analysis aimed at evaluating the diagnostic accuracy of TCCD in the stratification of intracranial steno-occlusions among CVD patients. A total of six databases-Embase, CINAHL, Medline, PubMed, Google Scholar, and Web of Science (core collection)-were searched for studies that assessed the diagnostic accuracy of TCCD in stratifying ICASs. The meta-analysis was performed using Meta-DiSc 1.4. The Quality Assessment of Diagnostic Accuracy Studies tool version 2 (QUADAS-2) assessed the risk of bias. Eighteen studies met all of the eligibility criteria. TCCD exhibited a high pooled diagnostic accuracy in stratifying intracranial steno-occlusions in patients presenting with CVD when compared to DSA as a reference standard (sensitivity = 90%; specificity = 87%; AUC = 97%). Additionally, the ultrasound parameters peak systolic velocity (PSV) and mean flow velocity (MFV) yielded a comparable diagnostic accuracy of "AUC = 0.96". In conclusion, TCCD could be a noble, safe, and accurate alternative imaging technique to DSA that can provide useful diagnostic information in stratifying intracranial steno-occlusions in patients presenting with CVD. TCCD should be considered in clinical cases where access to DSA is limited.

Sonothrombolysis for Ischemic Stroke.

Stroke is a major cause of death and disability globally, with ischemic stroke being the predominant mechanism. While spontaneous recanalization may occur, significant neuronal injury would have occurred in the interim. Intravenous thrombolysis administered within the first 4.5 h after stroke onset and endovascular thrombectomy within 24 h in patients with a salvageable penumbra improves functional independence. Ultrasound has been shown in both in vivo and in vitro models to enhance clot lysis, even more-so in the presence of thrombolytic agents. The use of transcranial Doppler and transcranial color-coded Doppler ultrasound in acute IS has been reported in case series, case-controlled studies, and clinical trials. While ultrasound at a frequency of 300 kHz increases the risk of intracranial hemorrhage, the 2 MHz range ultrasound aids thrombolysis and improves recanalization without significantly increasing the risk of symptomatic intracranial hemorrhage. Despite this, functional independence was not increased in clinical trials, nor was a benefit shown with the adjunctive use of microbubbles or microspheres. Nonetheless, newer technologies such as endovascular ultrasound, endovascular delivery of microbubbles, and thrombolytic-filled microbubbles await clinical trials. More evidence is needed before sonothrombolysis can be routinely used in the hyperacute management of ischemic stroke.

A Comparative Study of Transcranial Color-Coded Doppler (TCCD) and Transcranial Doppler (TCD) Ultrasonography Techniques in Assessing the Intracranial Cerebral Arteries Haemodynamics.

Cerebrovascular disease (CVD) poses a major public health and socio-economic burden worldwide due to its high morbidity and mortality rates. Accurate assessment of cerebral arteries' haemodynamic plays a crucial role in the diagnosis and treatment management of CVD. The study compared a non-imaging transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in quantifying middle cerebral arteries (MCAs) haemodynamic parameters. A cross-sectional study involving 50 healthy adults aged ≥ 18 years was conducted. The bilateral MCAs were insonated via three trans-temporal windows (TTWs-anterior, middle, and posterior) using TCD, cTCCD, and ncTCCD techniques. The MCA peak systolic velocity (PSV) and mean flow velocity (MFV) were recorded at proximal and distal imaging depths that could be visualised on TCCD with a detectable spectral waveform. A total of 152 measurements were recorded in 41 (82%) subjects with at least one-sided open TTW across the three techniques. The mean PSVs measured using TCD, ncTCCD, and cTCCD were 83 ± 18 cm/s, 81 ± 19 cm/s, and 93 ± 21 cm/s, respectively. There was no significant difference in PSV between TCD and ncTCCD (bias = 2 cm/s, p = 1.000), whereas cTCCD yielded a significantly higher PSV than TCD and ncTCCD (bias = -10 cm/s, p < 0.001; bias = -12 cm/s, p ≤ 0.001, respectively). The bias in MFV between TCD and ncTCCD techniques was (bias = -0.5 cm/s; p = 1.000), whereas cTCCD demonstrated a higher MFV compared to TCD and ncTCCD (bias = -8 cm/s, p < 0.001; bias = -8 cm/s, p ≤ 0.001, respectively). TCCD is a practically applicable imaging technique in assessing MCA blood flow velocities. cTCCD is more accurate and tends to give higher MCA blood flow velocities than non-imaging TCD and ncTCCD techniques. ncTCCD is comparable to non-imaging TCD and should be considered in clinical cases where using both TCD and TCCD measurements is needed.

Point-of-care brain ultrasound and transcranial doppler or color-coded doppler in critically ill neonates and children.

In critically ill neonates, brain ultrasound for diagnosis and follow-up of the most common cerebral pathologies of the neonatal period may be considered the standard of care. Data are needed about the possible role of doppler techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles. In pediatric critical care, doppler based techniques should be routinely adopted to assess and monitor cerebral hemodynamics. New technologies and more evidence are needed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles. • In critically ill neonates, brain ultrasound for early diagnosis and follow-up of the most common cerebral and neurovascular pathologies of the neonatal period is a cornerstone of daily practice. In critically ill children, doppler-based techniques are more routinely used to assess cerebral hemodynamics and autoregulation after acute brain injury and to screen patients at risk for vasospasm or stroke (e.g., sickle cell diseases, right-to-left shunts). • In critically ill neonates, research is currently focusing on the use of novel high frequency probes, even higher than 10 MHz, especially for extremely preterm babies. Furthermore, data are needed about the role of doppler based techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles, also integrated with a non-invasive assessment of brain oxygenation. In pediatric critical care, new technologies should be developed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles. Furthermore, large multicenter studies are needed to clarify role and accuracy of doppler-based techniques to assess cerebral perfusion pressure and its changes after treatment interventions.

Role of Advanced Hemodynamic Ultrasound Evaluation in the Differential Diagnosis of Middle Cerebral Artery Stenosis: Introducing Morphological Criteria.

The aim of the work described here was to determine the possible impact of the new technique advanced hemodynamic ultrasound evaluation (AHUSE) in identification of severe intracranial stenosis. Transcranial Doppler (TCD) and transcranial color-coded Doppler (TCCD) provide reliable velocimetric data, the indirect analysis of which allows us to obtain information on the patency of vessels and assumed stenosis range. However, very tight stenoses (>95%) cannot be detected with velocimetric criteria because of spectrum drops and the absence of high velocities, so that the right curve of the Spencer equation cannot be solved. Likewise, high velocities are not detected when analyzing morphologically long stenosis. Furthermore, the current classifications based on velocimetric criteria do not provide any categorization on stenoses with multiple acceleration points (MAPs). With this Technical Note we aim to introduce, in addition to velocimetric criteria, more morphological criteria based on TCCD with the algorithm of AHUSE to optimize the characterization of intracranial stenosis (IS). TCCD-AHUSE relies on intensity-based next-generation techniques and can be used to identify IS with MAPs and simultaneously perform a morphological assessment of the stenosis length. We introduce a new technical ultrasound (U) approach that we tested in a sample of four different types of stenoses combining velocimetric data and AHUSE using Esaote Microvascularization (MicroV) technique to the M1 tract of the middle cerebral artery (MCA). The authors believe that a multiparametric evaluation is more sensitive and supports the clinician by introducing the morphological concept, not just the velocimetric concept, to differentiate the IS pattern of MCA. The potential for developing a diagnostic/prognostic algorithm is discussed.

Ultrasonographic Vasospasm and Outcome of Posterior Reversible Encephalopathy and Cerebral Vasoconstriction Syndromes.

Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) are often complicated by vasospasm and ischemia. Monitoring with transcranial color-coded Doppler (TCCD) could be useful, but its role is not established. We studied the incidence of ultrasonographic vasospasm (uVSP) in PRES/RCVS and its relationship with ischemic lesions and clinical outcome. We conducted a multicenter retrospective study of all patients with PRES/RCVS from 2008 to 2020 who underwent TCCD and magnetic resonance imaging (MRI). TCCD exams were analyzed for uVSP. Diffusion-weighted MRI was analyzed for positive lesions (DWI-positive). Functional outcome was assessed by modified Rankin scale (mRS) at 90 days. The associations with outcomes were determined by logistic regression. We included 80 patients (mean age of 46 (standard deviation, 17) years; 66% females; 41 with PRES, 28 with RCVS and 11 with overlap phenotype). uVSP was detected in 25 (31%) patients. DWI-positive lesions were more often detected in uVSP-positive than uVSP-negative patients (36% vs. 15%; adjusted odds ratio [aOR] 4.05 [95% CI 1.06 - 15.5], P=0.04). DWI-positive lesions were independently associated with worse functional prognosis (mRS 2-6, 43% vs. 10%; aOR, 10 [95% CI 2.6 - 43], P<0.01). Having additional uVSP further increased the odds of a worse outcome (P interaction=0.03). Ultrasonographic vasospasm was detected in a third of patients with PRES/RCVS and was associated with brain ischemic lesions. TCCD bedside monitoring can help to stratify patients at risk for cerebral ischemia, a strong predictor of functional outcome.

Altered Cerebral Vasoreactivity on Transcranial Color-Coded Sonography Related to Akinetic-Rigid Phenotype of Parkinson's Disease: Interim Analysis of a Cross-Sectional Study.

A correlation between worse functional outcomes in Parkinson's disease (PD) patients with cerebrovascular disease (CVD) or the Akinetic-rigid phenotype has been argued in recent studies. We aimed to evaluate the association of cerebral hemodynamics impairments, assessed by Transcranial Color-coded Doppler sonography (TCCS), on PD patients with different phenotypes of the disease and with risk factors for CVD. Idiopathic PD patients (n = 51) were divided into motor subtypes: Akinetic-rigid (AR) (n = 27) and Tremor-dominant (TD) (n = 24) and into two groups regarding vascular risk factors: when ≥2 were present (PDvasc) (n = 18) and <2 (PDnvasc) (n = 33). In a parallel analysis, the Fazekas scale on brain magnetic resonance imaging (MRI) was applied to a sample to assess the degree of leukoaraiosis. TCCS examinations were prospectively performed obtaining middle cerebral artery Mean Flow Velocities (Vm), Resistance Index (RI), and Pulsatility Index (PI). The Breath-Holding Index (BHI) was calculated to assess cerebrovascular reactivity (cVR). Standardized functional scales were administered (UPDRS III and Hoehn&Yahr). The phenotype groups were similar in age, disease duration and demographic parameters, but there were significantly higher H&Y scores than TD group. cVR was impaired in 66.7% of AR vs. 37.5% of TD. AR group exhibited lower BHI (0.53 ± 0.31 vs. 0.91 ± 0.62; p = 0.000), lower Vm after apnea (44.3 ± 9.0 cm/s vs. 53.4 ± 11.4 cm/s; p = 0.003), higher PI (0.91 ± 0.26 vs. 0.76 ± 0.12; p = 0.000) and RI (0.58 ± 0.11 vs. 0.52 ± 0.06; p = 0.021). PDvasc group showed higher PI (0.98 vs. 0.76; p = 0.001) and higher frequency of altered cVR (72.2% vs. 42.2%; p = 0.004). There was a significant predominance of higher values on Fazekas scale in the PDvasc group. We found no difference between the Fazekas scale when comparing motor subtypes groups but there was a trend toward higher scores in the AR phenotype. TCCS, a cost-effective method, displayed impaired cVR in Parkinsonian patients with risk factors for CVD with higher degree of MRI leukoaraiosis. PD patients with the AR disease phenotype also presented impaired cVR on TCCS and greater functional impairment, although with just a trend to higher scores on MRI Fazekas.

Chronic Endothelial Dysfunction after COVID-19 Infection Shown by Transcranial Color-Coded Doppler: A Cross-Sectional Study.

In addition to respiratory symptoms, COVID-19 often causes damage to many other organs, especially in severe forms of the disease. Long-term consequences after COVID-19 are common and often have neurological symptoms. Cerebral vasoreactivity may be impaired after acute COVID-19 and in our study, we wanted to show how constant and reversible are the changes in brain vasoreactivity after infection. This cross-sectional observational study included 49 patients diagnosed with COVID-19 and mild neurological symptoms 300 days after the onset of the disease. We used a transcranial color-coded Doppler (TCCD) and a breath-holding test (BHT) to examine cerebral vasoreactivity and brain endothelial function. We analyzed the parameters of the flow rate through the middle cerebral artery (MCA): peak systolic velocity (PSV), end-diastolic velocity (EDV), mean velocity (MV), resistance index (RI) and pulsatility index (PI), and we calculated the breath-holding index (BHI). Subjects after COVID-19 infection had lower measured velocity parameters through MCA at rest period and after BHT, lower relative increases of flow velocities after BHT, and lower BHI. We showed that subjects, 300 days after COVID-19, still have impaired cerebral vasoreactivity measured by TCCD and they have chronic endothelial dysfunction.

Transcranial Color-Coded Doppler Cerebral Hemodynamics Following Aerobic Exercise Training: Outcomes From a Pilot Randomized Clinical Trial.

An active lifestyle with regular exercise is thought to decrease or delay the onset of Alzheimer dementia through increasing blood flow to the brain. We examined the mean flow velocity (MFV) and pulsatility index (PI) in the middle cerebral arteries of individuals randomized into two groups-a Usual Physical Activity (UPA) group and an Enhanced Physical Activity (EPA) exercise intervention group-to determine if exercise training is related to changes in cerebral blood flow. We examined 23 participants, randomized into a UPA group (n=12) and an EPA group (n=11), with transcranial color-coded Doppler (TCCD) and cardiorespiratory fitness (VO2peak, mL/kg/min) testing at baseline and following a 26-week intervention. TCCD was used to measure MFV and PI. Participants in the EPA group completed supervised aerobic exercise training for 26 weeks. Kendall's tau b correlation was used to examine relationships between variables. The Wilcoxon Rank Sum tests were used to examine changes between the UPA and EPA groups. There was no significant change in MFV or PI in the UPA group or the EPA group (p-values >0.05) between baseline and 26 weeks; the change between the UPA and EPA groups was also not significant (p=0.603). There was no evidence of an association between change in VO2peak and change in MFV or PI (all p-values >0.05). Participants in the EPA group significantly increased their VO2peak compared to the UPA group (p=0.027). This study did not demonstrate evidence of a significant change in the MFV in the middle cerebral arteries or evidence of a significant change in the PI between UPA and EPA groups. Future studies should be performed in larger cohorts and should consider use of personalized exercise programs to maximize understanding of how cerebrovascular hemodynamics change in structure and function with exercise for adults at risk for Alzheimer dementia.

Transcranial Color-Coded Doppler Cerebral Hemodynamics Following Aerobic Exercise Training: Outcomes From a Pilot Randomized Clinical Trial for CME credit September 2022

Transcranial Color-Coded Doppler Cerebral Hemodynamics Following Aerobic Exercise Training: Outcomes From a Pilot Randomized Clinical Trial for CME credit September 2022

Retroauricular/Transcranial Color-Coded Doppler Ultrasound Approach in Junction With Ipsilateral Neck Compression on Real-Time Hydroacoustic Variation of Venous Pulsatile Tinnitus.

Alterations in dural venous sinus hemodynamics have recently been suggested as the major contributing factors in venous pulsatile tinnitus (PT). Nevertheless, little is known about the association between real-time alterations in hemodynamics and the subjective perception of venous PT. This study aimed to investigate the hydroacoustic correlations among diverticular vortices, mainstream sinus flow, and PT using various Doppler ultrasound techniques. Nineteen venous PT patients with protrusive diverticulum were recruited. The mainstream sinus and diverticular hemodynamics before and after ipsilateral internal jugular vein (IJV) compression were investigated using an innovative retroauricular color-coded Doppler (RCCD) method to examine the correlation between the disappearance of PT and hemodynamic alterations. To reveal the hydroacoustic characteristics of disparate segments of venous return, a computational fluid dynamics (CFD) technique combined with the transcranial color-coded Doppler method was performed. When the ipsilateral IJV was compressed, PT disappeared, as the mean velocity of mainstream sinus flow and diverticular vortex decreased by 51.2 and 50.6%, respectively. The vortex inside the diverticulum persisted in 18 of 19 subjects. The CFD simulation showed that the flow amplitude generated inside the transverse–sigmoid sinus was segmental, and the largest flow amplitude difference was 20.5 dB. The difference in flow amplitude between the mainstream sinus flow and the diverticular flow was less than 1 dB. In conclusion, the sensation of PT is closely associated with the flow of kinetic energy rather than the formation of a vortex, whereby the amplitude of PT is correlated to the magnitude of the flow velocity and pressure gradient. Additionally, the range of velocity reduction revealed by the RCCD method may serve as a presurgical individual baseline curative marker that may potentially optimize the surgical outcomes.

Transcranial color-coded doppler and digital subtraction angiography in the evaluation of middle cerebral artery abnormality in a patient with neurofibromatosis type 1

In patients with neurofibromatosis type 1 (NF1), cerebral vascular abnormalities can manifest in the form of stenosis, occlusions and aneurysms. In case of arterial obstructions, cerebral perfusion is made possible by the compensation mechanisms of collaterals at different levels. Many imaging methods such as Magnetic Resonance Angiography (MR-A), Computed Tomography Angiography (CT-A), Digital Subtraction Angiography (DSA), and Transcranial Doppler or Transcranial Color-Coded Doppler (TCD/TCCD) can be used to detect structural and hemodynamic changes in the cerebral circulation in these patients. We present the case of a NF1 patient with an anomaly of the left middle cerebral artery. The use of vascular imaging methods allowed elucidating the pathogenetic mechanisms of the vascular disease and planning the follow-up.

Comparison Between Transcranial Color-Coded Duplex Doppler and Contrast Enhanced Transcranial Color-Coded Duplex Doppler After Subarachnoid Aneurysmal Hemorrhage.

Transcranial color-coded duplex Doppler (TCCD) is commonly used to detect and monitor vasospasm in subarachnoid aneurysmal hemorrhage (aSAH). However, contrast enhanced TCCD (CE-TCCD) may be more effective. The objective of this study was to compare the accuracy of TCCD and CE-TCCD in the detection of vasospasm. This study was a prospective comparison of TCCD and CE-TCCD for the detection of vasospasm, using computed tomography angiography (CT Angio)as a reference examination. The setting was the Department of Anesthesiology and Intensive Care at the Bicêtre University Hospital in Le Kremlin Bicêtre, France. TCCD and CE-TCCD were performed in 47 patients admitted to the intensive care unit (ICU) following aSAH over a 7-month period. TCCD and CE-TCCD were performed at ICU admission and between days 7 and 10. We aimed to visualize the seven intracranial arteries of the circle of Willis. Vasospasm diagnosis was assessed byCT Angio and graded as moderate when the percentage change in arterial diameter since admission was between 25 and 50% or as severe when the percentage change was greater than 50%. On ICU admission, TCCD allowed visualization of all intracranial arteries in 16 (34%) of 47 patients, whereas CE-TCCD allowed visualization of all vessels in 37 (79%) of 47 patients (p < 0.001). These results were consistent between days 7 and 10. The proportions of middle cerebral arteries (MCAs), anterior cerebral arteries(ACAs) and posterior cerebral arteries(PCAs) visualized were greater with CE-TCCD. There was no difference in the visualization of basilar arteries(BAs). We performed vasospasm analysis on 67 of 94 MCAs in 47 patients. Area under the curve(AUC) of mean flow velocity to detect MCA vasospasm (moderate and severe) was 0.86 (0.58-1.00) for TCCD and 0.90 (0.77-1.00) for CE-TCCD. AUC of mean velocity to detect severe MCA vasospasm was 0.86 (0.58-1.00) for TCCD and 0.90 (0.77-1.00) for CE-TCCD, without any significant difference between the two techniques. For other arteries, the accuracy of TCCD and CE-TCCD to diagnose vasospasm was poor. CE-TCCD allows better visualization of intracranial arteries in patients with aSAH. The accuracy of CE-TCCD to screen severe MCA vasospasm is similar to that of TCCD. CE-TCCD is an alternative tool for monitoring patients with aSAH without a temporal bone window for an ultrasound.

Intracranial Large Artery Disease is Independently Associated with Poor Functional Outcome in a Cohort of Ethnic South Asian Ischemic Stroke Patients.

Intracranial large artery disease (ICLAD) in ischemic stroke patients is associated with an increased risk for recurrent stroke; however, it is not known if ICLAD influences functional status following stroke. We studied the 6-month functional outcome in south Asian ischemic stroke patients and compared those with and without ICLAD. This is a prospective cohort study of consecutive south Asian ischemic stroke patients. ICLAD was assessed with transcranial color-coded Doppler ultrasound or magnetic resonance angiography. Functional outcomes were obtained via telephone interviews with poor outcome defined as modified Rankin scale of 3-6. Of 216 ischemic stroke patients studied, 203 (93.9%) had follow-up data, of whom 50.7% (103) had ICLAD. Patients with ICLAD had a higher prevalence of hypertension (P < 0.001), hyperlipidemia (P = 0.047), ischemic heart disease (P = 0.030), and extracranial carotid disease (P = 0.005). A higher proportion of patients with ICLAD had poor functional outcome at 6 months (30.1%) versus those without ICLAD (13.0%) (P = 0.004). After adjusting for age, sex, hypertension, hyperlipidemia, diabetes, ischemic heart disease, atrial fibrillation, extracranial carotid stenosis, and recurrent vascular events, patients with ICLAD were 3.01 (95% confidence interval: 1.35-7.10) times more likely than those without ICLAD to have poor functional outcome. The presence of ICLAD rendered poorer functional prognosis after stroke. These findings support the specific evaluation of the benefits of known acute stroke treatments such as thrombolysis, as well as investigation of potential novel strategies such as acute stenting.

Association between Tomographic Characteristics of the Temporal Bone and Transtemporal Window Quality on Transcranial Color Doppler Ultrasound in Patients with Stroke or Transient Ischemic Attack

Transcranial color-coded Doppler (TCCD) is an ultrasonographic technique used to obtain and evaluate images of the cerebral parenchyma and to assess blood flow velocities of the intracranial vessels. One of the major limitations of TCCD is the failure to insonate through the transtemporal window, which occurs in about 5%–44% of patients. Temporal bone thickness has been strongly associated with transtemporal window failure (TWF). The aims of the study were to evaluate the association between TWF on TCCD and radiologic findings on computed tomography of the skull along with the demographic characteristics of patients with acute stroke or transient ischemic attack (TIA), and to propose a classification for transcranial window quality (TWQ) on B-mode scan of TCCD. A total of 187 consecutive patients with acute stroke or TIA were included. Among them, 21.9% had TWF and 34.8% had TWQ categorized as insufficient on B-mode scan of TCCD. On logistic regression, age (odds ratio [OR] = 1.07, 95% confidence interval [CI]: 1.03–1.12, p < 0.001), female sex (OR = 5.99, 95% CI: 2.09–17.16, p = 0.001), pneumatized temporal bone (OR = 7.90, 95% CI: 1.95–32.03, p = 0.004) and temporal bone thickness (OR = 3.04, 95% CI: 1.73–5.35, p < 0.001) were independent predictors of TWF, even after adjusting for confounders. These findings may help to select patients in whom echogenic contrast or even other imaging methods could be used to assess intracranial vessels.

A functional assessment of the circle of Willis before aortic arch surgery using transcranial Doppler

BackgroundAntegrade selective cerebral perfusion (ASCP) with systemic moderate hypothermia is routinely used as brain protection during aortic arch surgery. Whether ASCP should be delivered unilaterally (u-ASCP) or bilaterally (bi-ASCP) remains controversial. MethodsWe routinely studied the functional anatomy of the circle of Willis (CoW in all patients scheduled for arch surgery using transcranial color-coded Doppler over a decade. On the basis of these data, we classified observed functional variants as being “safe,” “moderately safe,” or “unsafe” for u-ASCP. ResultsFrom January 2005 to June 2015, 1119 patients underwent aortic arch surgery in our institution. Of these, 636 patients had elective surgery performed with ASCP. Preoperative full functional assessment of the CoW was possible in 61% of patients. A functionally complete CoW was found in only 27%. Of all variants, 72% were classified as being safe for u-ASCP, whereas 18% were moderately safe for u-ASCP, and 10% unsafe. Unsafe variants for bi-ASCP were observed in 0.5% of patients. ConclusionsThe risk of ischemic brain damage due to malperfusion is estimated to be substantially higher during right u-ASCP than during bi-ASCP. Bi-ASCP is therefore highly preferable over u-ASCP if the function of the CoW is unknown. We propose a tailored approach using this full functional assessment preoperatively by applying u-ASCP via the right subclavian artery when considered safely possible, and bi-ASCP when considered a necessity to prevent cerebral malperfusion, and thus thereby try to reduce the embolic stroke risk of ostial instrumentation in bi-ASCP.

Transcranial Doppler in the Diagnosis of Cerebral Vasospasm: An Updated Meta-Analysis.

To evaluate the performance of transcranial Doppler and transcranial color-coded duplex Doppler in patients with cerebral vasospasm due to aneurysm rupture. Angiography was considered as the gold standard comparator. Search in MEDLINE, Embase, and Central from January 2001 to October 2017, without language restriction. Bibliographies of retrieved articles were screened for additional studies. Randomized studies comparing transcranial Doppler or transcranial color-coded duplex Doppler with angiography in adults. Data were extracted independently by several investigators. Sensitivity and specificity were combined across studies using a bivariate model. Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used for reporting and Quality Assessment of Diagnostic Accuracy Studies-2 for quality assessment. We included 18 studies. Fifteen tested transcranial Doppler. For the middle cerebral artery (10 studies, 1,408 tests), the pooled sensitivity was 66.7% (95% CI, 55.9-75.9) and specificity was 89.5% (80.3-94.7). Three studies (278 tests) tested transcranial color-coded duplex Doppler for the middle cerebral artery. The pooled sensitivity was 81.5% (66.0-90.0), and specificity was 96.6% (93.0-98.0). For an arbitrarily chosen prevalence of vasospasm of 70%, positive and negative predictive values were 93.7% (88.9-96.6) and 53.4% (46.7-60.9) for transcranial Doppler and 98.2% (96.4-99.1) and 69.1% (56.1-80.9) for transcranial color-coded duplex Doppler. Assuming a high prevalence of vasospasm of the middle cerebral artery, both transcranial Doppler and transcranial color-coded duplex Doppler are likely to detect it, but neither is useful to exclude it. There is no convincing evidence that the accuracy of transcranial color-coded duplex Doppler is any better than that of transcranial Doppler. For arteries other than middle cerebral artery, there is a lack of evidence of the usefulness of transcranial Doppler.

Comparative Study of Transcranial Color-Coded Doppler and Transcranial Doppler Sonography in Middle Cerebral Artery

Comparative Study of Transcranial Color-Coded Doppler and Transcranial Doppler Sonography in Middle Cerebral Artery

MicroV Technology to Improve Transcranial Color Coded Doppler Examinations.

The purpose of this review is to provide an update on technology related to Transcranial Color Coded Doppler Examinations. Microvascularization (MicroV) is an emerging Power Doppler technology which can allow visualization of low and weak blood flows even at high depths, thus providing a suitable technique for transcranial ultrasound analysis. With MicroV, reconstruction of the vessel shape can be improved, without any overestimation. Furthermore, by analyzing the Doppler signal, MicroV allows a global image of the Circle of Willis. Transcranial Doppler was originally developed for the velocimetric analysis of intracranial vessels, in particular to detect stenoses and the assessment of collateral circulation. Doppler velocimetric analysis was then compared to other neuroimaging techniques, thus providing a cut-off threshold. Transcranial Color Coded Doppler sonography allowed the characterization of vessel morphology. In both Color Doppler and Power Doppler, the signal overestimated the shape of the intracranial vessels, mostly in the presence of thin vessels and high depths of study. In further neurosonology technology development efforts, attempts have been made to address morphology issues and overcome technical limitations. The use of contrast agents has helped in this regard by introducing harmonics and subtraction software, which allowed better morphological studies of vessels, due to their increased signal-to-noise ratio. Having no limitations in the learning curve, in time and contrast agent techniques, and due to its high signal-to-noise ratio, MicroV has shown great potential to obtain the best morphological definition.

Role of Noninvasive Imaging of Cerebral Arterial System in Ischemic Stroke: Comparison of Transcranial Color-coded Doppler Sonography with Magnetic Resonance Angiography.

Aim:To determine the accuracy of transcranial color-coded Doppler sonography (TCCS) in the evaluation of cerebral arterial system in patients with ischemic stroke attending a tertiary care hospital in South India.Objectives:(1) To describe the topographical distribution of atherosclerotic lesions in the cerebral circulation in patients presenting with ischemic stroke from the Indian subcontinent and (2) to determine the accuracy of TCCS for detection and quantification of intracranial stenoses in various segments of the intracerebral arterial system in comparison with magnetic resonance angiography (MRA).Materials and Methods:The demographic profile and risk factors of consecutive patients who presented to neurology outpatient department with cerebral ischemia and scheduled for MRA were determined. These patients had undergone neck Doppler, TCCS, and MRA. The agreement between the MRA and TCCS was assessed using kappa statistics. The sensitivity, specificity, and positive and negative predictive values of TCCS as compared to MRA were calculated.Results:Ninety patients were included in the final analysis. Intracranial atherosclerosis was found in 35.6% of cases. The agreement between TCCS and MRA in detecting lesions for the different arterial segments in the intracranial circulation was 0.83 for anterior cerebral artery (ACA), 0.66 for M1 segment of middle cerebral artery (MCA), 0.45 for M2 segment of MCA, 0.86 for terminal internal carotid artery (TICA), 0.46 for posterior cerebral artery (PCA), and 0.81 for vertebral artery (VA). The sensitivity for the detection of hemodynamically significant arterial lesions in different vascular segments was 100%, 70%, 33.3%, 90.9%, 33.3%, and 72.7% for ACA, M1, M2, TICA, PCA, and VA, respectively.Conclusion:Intracranial atherosclerosis was found to be the predominant distribution of cerebral atherosclerosis. TCCS is a safe method for evaluation of proximal basal cerebral arteries in the intracranial circulation with relatively better sensitivity in the anterior circulation.