Transcranial Color-coded Doppler Sonography Research Articles

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.

Case Analysis of Persistent Vasospasm after Cerebral Artery Aneurysm Rupture by Using Transcranial Color Coded Doppler Ultrasonography

Case Analysis of Persistent Vasospasm after Cerebral Artery Aneurysm Rupture by Using Transcranial Color Coded Doppler Ultrasonography

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.

Applications of Transcranial Color-Coded Sonography in the Emergency Department.

Transcranial color-coded Doppler sonography is a noninvasive bedside ultrasound application that combines both imaging of parenchymal structures and Doppler assessment of intracranial vessels. It may aid in rapid diagnoses and treatment decision making of patients with intracranial emergencies in point-of-care settings. This pictorial essay illustrates the technical aspects and emergency department applications of transcranial color-coded Doppler sonography, and provides some rationale for implementation of this technique into the emergency department practice.

Correlation of Homocysteine with Cerebral Hemodynamic Abnormality, Endothelial Dysfunction Markers, and Cognition Impairment in Patients with Traumatic Brain Injury

This study aimed to assess any correlation between serum levels of homocysteine (Hcy) and markers of cerebral hemodynamics, endothelial dysfunction, and cognition impairment in patients with traumatic brain injury (TBI). By a cross-sectional study, all clinical data and serum levels of homocysteine of 85 TBI patients were collected. The pulsatility indices (PIs) of the middle cerebral artery were recorded by transcranial color-coded Doppler ultrasonography and cerebrovascular reactivity was measured by the increase in middle cerebral artery flow velocity in response to 5% inhaled CO2. Serum levels of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1), cognition status by Montreal Cognitive Assessment, and Mini-Mental State Examination were measured in all participants. Totally, 85 patients including 51.76% male and the mean age of 54.48 years were studied. The level of Hcy in patients who died in the hospital or during 6 months after TBI was significantly higher than in survivors (P=0.045, P= 0.020, respectively). Also, the levels of ICAM-1, VCAM-1, and PI in deceased patients were higher than their figures in survivors in both hospital and 6-month follow-ups (P= 0.450, P= 0.000; P= 0.072, P= 0.000, P= 0.090, and P= 0.000, respectively). Cerebrovascular reactivity in deceased patients was significantly lower than that in alive individuals (P= 0.008 and P= 0.000, respectively). A significant correlation was found between Hcy with cognition impairment according to Montreal Cognitive Assessment, Mini-Mental State Examination, and cerebral hemodynamic status according to PI (P= 0.000 for all). Also, this correlation was shown between Hcy with ICAM-1 and VCAM-1 in hospital and 6-month follow-ups (P= 0.000 for both). Hcy has a significant correlation with markers of cerebrovascular, endothelial, and cognition abnormality in TBI patients.

Italian symptomatic intracranial atherosclerosis study (ISIDE) : A multicenter transcranial ultrasound evaluation.

There are currently no data available on the prevalence of symptomatic intracranial atherosclerosis (ICAS) in Italy. The aim of this prospective, multicenter, hospital-based, transcranial ultrasound study was to establish the prevalence of ICAS among patients hospitalized with acute ischemic stroke. At 11 stroke centers across Italy, patients consecutively admitted for their first ever acute ischemic stroke were assessed prospectively over a 24-month period either with transcranial color-coded Doppler sonography (TCCS) or transcranial Doppler (TCD) according to validated criteria. ICAS was diagnosed when there was an evidence of a cerebral infarction in the territory of a≥50% stenosis detected by TCCS/TCD and confirmed by magnetic resonance angiography or computed tomography angiography. A total of 1134 patients were enrolled, 665 of them (58.6%) men, with a mean age of 71.2±13.3years. ICAS was recorded in 99 patients (8.7% of the whole sample, 8.9% among Caucasians), most commonly located in the anterior circulation (63 of 99, 5.5%). After adjusting for potential confounders, multivariate analysis identified carotid/vertebral≥50% stenosis [odds ratio (OR) 2.59, 95% (confidence interval) CI 1.77-6.33; P=0.02] and hypercholesterolemia (OR 1.38, 95% CI 1.02-1.89; P=0.02) as being independently associated with ICAS. ICAS is a surprisingly relevant cause of ischemic stroke in Italy, identified in almost 9% of first-ever stroke patients. It is more prevalent in the anterior circulation and independently associated with hemodynamically significant cervical vessel atherosclerosis and hypercholesterolemia. These findings support the systematic use of transcranial ultrasound to identify ICAS in patients presenting with acute ischemic stroke and in cases with≥50% cervical vessel stenoses.

Clinical Outcomes of Carotid Endarterectomy in Symptomatic and Asymptomatic Patients with Ipsilateral Intracranial Stenosis.

The risk of perioperative stroke and the benefits of carotid endarterectomy (CEA) remain uncertain in the case of an ipsilateral intracranial stenosis. The aim of this observational study was to analyze the early and late outcomes of CEA in patients with a carotid tandem lesion (CTL), defined as a severe stenosis at the bifurcation with any concomitant lesion ≥50 % involving the intracranial portion of the ipsilateral internal carotid artery or the main trunk of the anterior or middle cerebral artery. From 2000 to 2009, 1143 patients underwent CEA for symptomatic or asymptomatic extracranial carotid stenosis according to the NASCET and ACAS recommendations, respectively. CTLs were diagnosed in 219 patients (19.2 %) by extracranial and transcranial color-coded Doppler sonography combined with noninvasive brain imaging studies. The primary endpoints of the study were perioperative (30-day) stroke and death, and any ipsilateral ischemic adverse events during the follow-up, which ranged from 0.1 to 10 years (mean 4.9 ± 3.3 years). The rates of the primary endpoints were compared between patients with (group I) and without CTL (group II). Overall, 219 CEAs were performed in group I and 924 in group II. Nearly two in three of the carotid lesions (777 of 1143, 68 %) were symptomatic at presentation (62.1 % in group I vs 69.4 % in group II; p = 0.03), with a 23.8 % rate of stroke (21.9 % in group I vs 24.2 % in group II; p = 0.85). There were 2 (0.9 %) perioperative ipsilateral strokes in group I and 5 (0.5 %) in group II (p = 0.62), and no deaths. The 5-year ipsilateral stroke-free, any stroke-free, and overall survival rates did not differ significantly between patients with and without CTL. This study has shown that patients with and without CTL who underwent CEA had a similar occurrence of perioperative adverse events (probably due to the extremely low incidence of perioperative complications) and comparable late outcomes, suggesting that the presence of CTL does not justify refusing CEA for patients who could benefit from it.

Low prevalence of collateral cerebral circulation in the circle of Willis in patients with severe carotid artery stenosis and recent ischemic stroke.

IntroductionThe circle of Willis is thought to play a key role in development of collateral flow in patients with internal carotid artery stenosis (ICAS).AimTo assess flow in the circle of Willis in patients with recent ischemic stroke (IS).Material and methodsThe study included 371 patients, 102 symptomatic with severe ICAS and recent IS (within the last 3 months) (group I) and 269 asymptomatic with severe ICAS (group II). Flow in the middle (MCA), anterior (ACA) and posterior (PCA) cerebral arteries and pattern of the cross-flow through anterior (ACoA) and posterior (PCoA) communicating arteries were assessed with transcranial color-coded Doppler ultrasonography (TCCD).ResultsThe ACoA or PCoA was less prevalent in group I than in group II (54% vs. 78%, p < 0.001 and 20% vs. 42%, p < 0.001, respectively), resulting in lower peak-systolic velocity (PSV) in the MCA in group I vs. group II (p = 0.015). Any collateral pathway was present in 67% of patients in group I, compared to 86% in group II (p < 0.001). Both PSV and end-diastolic (EDV) flow velocity in the ACA were lower in patients with recent IS, compared to asymptomatic subjects (71 ±24 cm/s vs. 86 ±34 cm/s, p < 0.001 and 32 ±12 cm/s vs. 37 ±17 cm/s, p = 0.038, respectively). Presence of ACoA or PCoA and higher PSV in the MCA and ACA were associated with significant risk reduction of IS (RR = 0.28 (95% CI = 0.16–0.49, p < 0.001), RR = 0.28 (95% CI = 0.15–0.52, p < 0.001), RR = 0.97 (95% CI = 0.96–0.99, p < 0.001), RR = 0.99 (95% CI = 0.98–0.99, p < 0.032), respectively). However, ROC curves failed to show reliable MCA or ACA PSV cut-offs for IS risk assessment.ConclusionsThe ACoA and PCoA seem to play a key role in the evaluation of IS risk in subjects with severe ICAS.

Asymptomatic intracranial arterial stenosis and metabolic syndrome: the APAC study.

PurposeThe metabolic syndrome (MetS) is a major risk factor for cardiovascular diseases. We investigated potential associations between MetS and asymptomatic intracranial arterial stenosis (ICAS) in a general population.MethodsThe community-based “Asymptomatic Polyvascular Abnormalities in Community Study” examined asymptomatic polyvascular abnormalities in a Chinese population aged 40+ years without history of stroke and coronary heart disease. MetS was defined by the International Diabetes Federation criteria. Asymptomatic ICAS was diagnosed by transcranial color-coded Doppler sonography.ResultsOut of 5393 study participants, asymptomatic ICAS was detected in 713 (13.2%) participants, and MetS in 1323 (24.5%) individuals. Prevalence of asymptomatic ICAS increased significantly from 7.5% to 24.2% with increasing number of MetS components. After adjusting for age, gender, physical activity, body mass index, low-density lipoprotein cholesterol and high-sensitivity C-reactive protein, MetS was significantly associated with asymptomatic ICAS (OR: 1.50; 95%CI: 1.23,1.83). Compared with the subgroup without MetS, the ORs for asymptomatic ICAS increased (P<0.0001) for each of 5 components of MetS from 1.71 (95%CI: 1.27,2.30), to 2.20 (95%CI: 1.63,2.98), 2.79 (95CI: 2.01,3.88), 3.08 (95%CI: 2.11,4.51) and 4.27 (95%CI: 2.22,8.20).ConclusionsIn multivariate analysis, MetS was an independent and additional factor associated with asymptomatic ICAS. Study participants with 5 MetS components had a 4 times higher risk of asymptomatic ICAS than participants with no MetS component.

Transcranial color-coded Doppler assessment of cerebral arteriovenous malformation hemodynamics in patients treated surgically or with staged embolization

ObjectiveThe etiology of hemodynamic disturbances following embolization or surgical resection of arteriovenous malformations (AVMs) has not been fully explained. The aim of the study was the assessment of the selected hemodynamic parameters in patients treated for cerebral AVMs using transcranial color-coded Doppler sonography (TCCS). Materials and methodsForty-six adult patients (28 males, 18 females, aged 41±13 years, mean±SD) diagnosed with AVMs who were consecutively admitted to the Department of Neurosurgery between 2000 and 2012 treated surgically or with staged embolization were enrolled in the study. All patients were examined with TCCS assessing mean flow velocity (Vm), the pulsatility index (PI) and vasomotor reactivity (VMR) in all main intracranial arteries. The examined parameters were assessed in the vessel groups (feeding, ipsilateral and contralateral to the AVM) and they were compared between the examinations, i.e. at admission, within 24h after the first embolization or surgical resection (I control), and before the second embolization (II control). ResultsIn feeders which were completely obliterated or surgically resected – I control examination showed a nonsignificant Vm decrease. The difference between Vm before embolization and II control examination was significant (102.0±47.8cm/s vs 54.3±19.4cm/s, p<0.01). A significant increase in PI (0.72±0.18 vs 0.94±0.24, p<0.01) and VMR (1.80±0.59 vs 2.78±0.78, p<0.01) of feeding vessels was observed in I control. No further increase in PI or in VMR was observed. In embolized feeding vessels after partial AVM embolization I control examination showed a significant decrease in Vm (116.1±32.6cm/s vs 93.4±33.0cm/s, p<0.01). No further significant decrease in Vm was noted. The pulsatility index increased significantly (I control, 0.54±0.11 vs 0.66±0.15, p<0.01) and then decreased nonsignificantly (II control). No statistically significant differences were found in VMR values between pretreatment, I and II control examinations. Both Vm in the ipsilateral internal carotid artery and the ratio of Vm of the embolized vessel to Vm of the corresponding contralateral vessel were significantly higher in I control examination compared to II control examination (111.8±44.0cm/s vs 101.3±40.6cm/s, p<0.01; 1.63±0.61 vs 1.37±0.62, p<0.01; respectively). No statistically significant correlation was observed between the decrease in Vm or the increase in PI in the embolized vessels and the reduction of AVM volume. In the nonembolized feeding vessels after partial AVM embolization II control examination revealed the increase in Vm and a significant decrease in PI (0.71±0.21 vs 0.62±0.16, p<0.01) compared to I examination. No statistically significant changes in the VMR value in the nonembolized feeders between the pretreatment, I and II control examinations were noted. ConclusionsThe decrease in Vm and the increase in the PI in the embolized feeding vessels after the first complete embolization or surgical resection is observed, whereas the PI returned to normal values before Vm does. The observed decrease in Vm and an increase in the PI in embolized AVM feeders after complete or partial embolization do not correlate with the extent of embolization. In these vessels a relative increase in blood flow velocity is maintained within the first 24h following embolization as compared to contralateral vessels. The increase in Vm is not related to disturbances in VMR. Blood redistribution to the nonembolized AVM feeders is observed after partial AVM embolization.

Extracranial venous hemodynamics in multiple sclerosis

A chronic state of impaired cerebral and cervical venous drainage, termed chronic cerebrospinal venous insufficiency (CCSVI), has recently been implicated in the pathogenesis of multiple sclerosis (MS). We performed a color-coded Doppler sonography case-control study to externally validate the CCSVI criteria. We prospectively evaluated consecutive patients with clinically definite MS and healthy volunteers using extracranial and transcranial color-coded Doppler sonography. The recently developed neurosonology criteria for CCSVI detection were used for interpretation of ultrasound assessments. The presence of venous reflux in cervical veins was assessed both in the sitting and upright position during a short period of apnea and after Valsalva maneuver. We recruited 42 patients with MS (mean age 39 ± 11 years, 17 men) and 43 control individuals (mean age 38 ± 12 years, 16 men). Very good/excellent intrarater and interrater agreement (κ values 0.82-1.00) was documented in 3 out of 5 CCSVI criteria. There was no evidence of stenosis or nondetectable Doppler flow in cervical veins in patients and controls. Reflux in internal jugular vein (IJV) was documented in 1 patient (2%) and 1 control subject (2%), both in sitting and supine posture during apnea. After performing Valsalva maneuver, we documented the presence of IJV valve incompetence in 3 patients with MS (7%) and 4 healthy volunteers (9%; p > 0.999). With established reproducibility of venous ultrasound testing, our data argue against CCSVI as the underlying mechanism of MS. Without further independent validation of CCSVI, potentially dangerous endovascular procedures, proposed as novel therapy for MS, should not be performed outside controlled clinical trials.

Brain-Derived Neurotrophic Factor Gene Val66Met Polymorphism Modulates Reversible Cerebral Vasoconstriction Syndromes

BackgroundReversible cerebral vasoconstriction syndrome (RCVS) could be complicated by cerebral ischemic events. Hypothetical mechanisms of RCVS involve endothelial dysfunction and sympathetic overactivity, both of which were reported to be related to brain-derived neurotrophic factor (BDNF). The study investigated the association between functional BDNF Val66Met polymorphism and RCVS.MethodsPatients with RCVS and controls were prospectively recruited and genotyped for the BDNF Val66Met polymorphism. Magnetic resonance angiography (MRA) and transcranial color-coded Doppler sonography were employed to evaluate cerebral vasoconstriction. Genotyping results, clinical parameters, vasoconstriction scores, mean flow velocities of the middle cerebral artery (VMCA), and Lindegaard indices were analyzed. Split-sample approach was employed to internally validate the data.Principal FindingsNinety Taiwanese patients with RCVS and 180 age- and gender-matched normal controls of the same ethnicity completed the study. The genotype frequencies did not differ between patients and controls. Compared to patients with Met/Met homozygosity, patients with Val allele had higher mean vasoconstriction scores of all arterial segments (1.60±0.72 vs. 0.87±0.39, p<0.001), VMCA values (116.7±36.2 vs. 82.7±17.9 cm/s, p<0.001), and LI (2.41±0.91 vs. 1.89±0.41, p = 0.001). None of the Met/Met homozygotes, but 38.9% of the Val carriers, had VMCA values of >120 cm/s (p<0.001). Split-sample validation by randomization, age, entry time or residence of patients demonstrated concordant findings.ConclusionsOur findings link BDNF Val66Met polymorphism with the severity of RCVS for the first time and implicate possible pathogenic mechanisms for vasoconstriction in RCVS.

Predictors of Cerebral Reperfusion Injury After Carotid Stenting: The Role of Transcranial Color-Coded Doppler Ultrasonography

To evaluate the possible role of transcranial color-coded Doppler ultrasonography (TCD) in predicting cerebral reperfusion injury (CRI) in patients undergoing carotid artery stenting (CAS) for internal carotid artery (ICA) stenosis. TCD was obtained in 210 patients (149 men; mean age 64.2+/-8.4 years, range 44-83) who underwent CAS for ICA stenosis averaging 86.7%+/-8.4%. Contralateral ICA occlusion or near occlusion (stenosis >90%) was present in 67 (31.9%) patients. TCD was performed before and 24 hours after CAS with assessment of peak systolic velocities (PSVs) in the ipsilateral middle cerebral artery (iMCA) and contralateral middle cerebral artery (cMCA). PSV ratios (PSVR) in the iMCA and cMCA were calculated from the PSVs before and after CAS. CRI syndrome occurred in 3 (1.4%) patients (2 intracranial bleedings, 1 subarachnoid hemorrhage). The mean iMCA and cMCA PSVRs were 2.66+/-0.19 and 4.16+/-2.77, respectively, in CRI patients, while the PSVRs in CAS patients without neurological sequelae were 1.56+/-0.46 and 1.21+/-0.39, respectively (both p<0.001). The combination of iPSVR>2.4 and cPSVR>2.4 occurred in 4 patients with bilateral ICA disease; 3 (75%) of them developed CRI (100% sensitivity and 99% specificity for CRI prediction). The following independent CRI predictors were identified: combined iPSVR>2.4 and cPSVR>2.4 (RR 2.06, CI 1.89 to 2.24; p<0.001), high cMCA PSV after CAS (RR 1.23, CI 1.13 to 1.34; p<0.001), and contralateral ICA occlusion (RR 1.13, CI 1.03 to 1.23; p = 0.007). TCD is an important tool in CRI risk evaluation. The combination of iPSVR>2.4 and cPSVR>2.4 is an independent CRI risk factor, along with contralateral ICA occlusion and high cMCA PSVs after CAS.

Impairment of cerebral hemodynamic response to the cold pressor test in patients with Parkinson's disease

Background and purpose Disturbance of the autonomic nervous system (ANS) is frequently encountered in Parkinson's disease (PD). In this study, we examined changes in systemic and cerebral hemodynamics during the cold pressor test (CPT) to determine whether cerebrovascular reactivity, controlled by the sympathetic nervous system, is intact or impaired in patients with PD. Methods Forty-nine patients with PD and 49 sex- and age-matched non-PD subjects were evaluated. Measurements were performed in the resting state and over a period of 1 min of CPT. The cerebral blood flow velocity (CBFV) and pulsatility index (PI) of the middle cerebral artery (MCA) were recorded by transcranial color-coded Doppler ultrasonography (TCCS). Mean arterial blood pressure (MAP), heart rate (HR), and end-tidal CO 2 (Et-CO 2) were investigated simultaneously. The resistance of the cerebrovascular bed (CVR) was calculated as the ratio of mean arterial blood pressure to mean cerebral blood flow velocity (V m). Changes of V m, PI and CVR in response to the cold pressor test were evaluated. Results Baseline values for control and PD subjects showed no statistical difference. CPT induced a significant increase in MAP, HR, and V m in both groups. Pulsatility index (PI) and CVR were decreased in both groups during CPT. Percent increases of V m ( P < 0.001) and MAP ( P = 0.011) were significantly higher while the percent decreases of PI ( P = 0.002) and CVR ( P = 0.007) were significantly decreased more in the non-PD group. Conclusions This study indirectly shows that ANS-mediated cerebrovascular reactivity is impaired in patients with PD. Further investigations are needed to confirm the hypothesis that using the cold pressor test to evaluate cerebrovascular reactivity might be beneficial in early diagnosis of impairment of ANS-mediated cerebrovascular autoregulation in patients with PD.

Detection and monitoring of cerebral hemodynamic disturbances with transcranial color-coded duplex sonography in patients after head injury

Reduced cerebral blood flow after severe head injury results in an increased risk of ischemic brain damage. Blood flow should therefore be monitored with a simple, reliable method. Transcranial color-coded Doppler sonography (TCCS) is an accepted tool for the diagnosis of cerebral vasospasm; however, its usefulness in evaluating patients with head injury has not been proven. Cerebral blood-flow velocity in the middle, anterior, and posterior cerebral arteries was measured with a 2.5 MHz probe (Aplio SSA 770A, Toshiba, Japan) in 36 subjects with moderate or severe head injury. Serial measurements of resistance index (RI), peak-systolic, end-diastolic, and mean velocity in the middle cerebral arteries were performed 2-24 h after head trauma and in the subsequent days during hospitalization. Immediately after head trauma, increased RI values, and unusually decreased blood-flow velocity (mainly in MCA) were observed. Microcirculation disturbances were suspected because the end-diastolic velocity had substantially diminished. Changes in blood-flow parameters correlated with the clinical state, and in most cases, a poor prognosis. In some patients, blood-flow velocity increased above the normal reference limit and this implied poor prognosis. Transcranial color-coded Doppler sonography is a reliable, repeatable, and accessible tool that provides information about cerebral blood-flow disturbances and may hold diagnostic and prognostic importance.

The influence of noise on blood flow in the basilar artery (BA) – measurements with transcranial color-coded duplex sonography (TCCD)

Acoustic stimuli are being reported as a cause of changes in resistance in the basilar artery (BA). It was the aim of this study to investigate this effect under standardized conditions dependent upon the intensity of the evoking stimulus. Twenty healthy subjects with normal hearing (male/female 14/6; mean age 26.4 years) were exposed to ‘pink noise’ for periods of 2 min at 75, 85 and 95 dB(A). Parallel to this, the Doppler spectrum of the BA and both the Pourcelot resistance index and the Gosling pulsatility index were measured by means of transcranial color-coded Doppler sonography. In comparison with the base value (at rest) a significant increase in resistance was noted during noise exposure. The noise-induced resistance changes could be interpreted as a consequence of changes in activity of the various centers of the auditory pathway and cerebral function. Further animal experiments may prove the connection between BA blood flow and resistance and their changes depending on different acoustic stimuli or different hearing pathophysiology.