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Background and Purpose: Transcranial Doppler (TCD) identifies acute stroke patients with arterial occlusion where treatment may not effectively open the blocked vessel. This study aimed to examine the clinical utility and prognostic value of TCD flow findings in patients enrolled in a multicenter prospective study (CLOTBUST‐PRO). Methods: Patients enrolled with intracranial occlusion on computed tomography angiography (CTA) who underwent urgent TCD evaluation before intravenous thrombolysis was included in this analysis. TCD findings were assessed using the mean flow velocity (MFV) ratio, comparing the reciprocal ratios of the middle cerebral artery (MCA) depths bilaterally (affected MCA‐to‐contralateral MCA MFV [aMCA/cMCA MFV ratio]). Results: A total of 222 patients with intracranial occlusion on CTA were included in the study (mean age: 64 ± 14 years, 62% men). Eighty‐eight patients had M1 MCA occlusions; baseline mean National Institutes of Health Stroke Scale (NIHSS) score was 16, and a 24‐hour mean NIHSS score was 10 points. An aMCA/cMCA MFV ratio of <.6 had a sensitivity of 99%, specificity of 16%, positive predictive value (PV) of 60%, and negative PV of 94% for identifying large vessel occlusion (LVO) including M1 MCA, terminal internal carotid artery, or tandem ICA/MCA. Thrombolysis in Brain Ischemia scale, with (grade ≥1) compared to without flow (grade 0), showed a sensitivity of 17.1%, specificity of 86.9%, positive PV of 62%, and negative PV of 46% for identifying LVO. Conclusions: TCD is a valuable modality for evaluating arterial circulation in acute ischemic stroke patients, demonstrating significant potential as a screening tool for intravenous/intra‐arterial lysis protocols. [ABSTRACT FROM AUTHOR]

Background and Purpose: Cerebral vasomotor reactivity (VMR) is vital for regulating brain blood flow and maintaining neurological function. Impaired cerebral VMR is linked to a higher risk of stroke and poor post‐stroke outcomes. This study explores the relationship between statin treatment intensity and VMR in patients with ischemic stroke. Methods: Seventy‐four consecutive patients (mean age 69.3 years, 59.4% male) with recent ischemic stroke were included. VMR levels were assessed 4 weeks after the index stroke using transcranial Doppler, measuring the breath‐holding index (BHI) as an indicator of the percentage increase in middle cerebral artery blood flow (higher BHI signifies higher VMR). Multistep multivariable regression models, adjusted for demographic and cerebrovascular risk factors, were employed to examine the association between statin intensity treatment and BHI levels. Results: Forty‐one patients (55%) received high‐intensity statins. Patients receiving high‐intensity statins exhibited a mean BHI of 0.85, whereas those on low‐intensity statins had a mean BHI of 0.67 (mean difference 0.18, 95% confidence interval: 0.13‐0.22, p‐value<.001). This significant difference persisted in the fully adjusted model (adjusted mean values: 0.84 vs. 0.68, p‐value:.008). No significant differences were observed in BHI values within patient groups on high‐intensity or low‐intensity statin therapy (all p‐values>.05). Furthermore, no significant association was found between baseline low‐density lipoprotein (LDL) levels and BHI. Conclusions: High‐intensity statin treatment post‐ischemic stroke is linked to elevated VMR independent of demographic and clinical characteristics, including baseline LDL level. Further research is needed to explore statin therapy's impact on preserving brain vascular function beyond lipid‐lowering effects. [ABSTRACT FROM AUTHOR]

Background and Purpose: Thresholds for abnormal transcranial Doppler cerebrovascular reactivity (CVR) studies are poorly understood, especially for patients with cerebrovascular disease. Using a real‐world cohort with cerebral arterial stenosis, we sought to describe a clinically significant threshold for carbon dioxide reactivity (CO2R) and vasomotor range (VMR). Methods: CVR studies were performed during conditions of breathing room air normally, breathing 8% carbon dioxide air mixture, and hyperventilation. The mean and standard deviation (SD) of CO2R and VMR were calculated for the unaffected side in patients with unilateral stenosis; a deviation of 2 SDs below the mean was chosen as the threshold for abnormal. Receiver operating characteristic (ROC) curves for both sides for patients with unilateral and bilateral stenosis were evaluated for sensitivity (Sn) and specificity (Sp). Results: A total of 133 consecutive CVR studies were performed on 62 patients with stenosis with mean±SD age 55±16 years. Comorbidities included hypertension (60%), diabetes (15%), stroke (40%), and smoking (35%). In patients with unilateral stenosis, mean±SD CO2R for the unaffected side was 1.86±0.53%, defining abnormal CO2R as <0.80%. Mean±SD CO2R for the affected side was 1.27±0.90%. The CO2R threshold predicted abnormal acetazolamide single‐photon emission computed tomography (SPECT) (Sn =.73, Sp =.79), CT/MRI perfusion abnormality (Sn =.42, Sp =.77), infarction on MRI (Sn =.45, Sp =.76), and pressure‐dependent exam (Sn =.50, Sp =.76). For the unaffected side, mean±SD VMR was 39.5±15.8%, defining abnormal VMR as <7.9%. For the affected side, mean±SD VMR was 26.5±17.8%. The VMR threshold predicted abnormal acetazolamide SPECT (Sn =.46, Sp =.94), infarction on MRI (Sn =.27, Sp =.94), and pressure‐dependent exam (Sn =.31, Sp =.90). Conclusions: In patients with multiple vascular risk factors, a reasonable threshold for clinically significant abnormal CO2R is <0.80% and VMR is <7.9%. Noninvasive CVR may aid in diagnosing and risk stratifying patients with stenosis. [ABSTRACT FROM AUTHOR]

Background and Purpose: Elevated mean flow velocity (MFV) on transcranial Doppler (TCD) is used to predict vasospasm after aneurysmal subarachnoid hemorrhage (SAH). Hyperemia should be considered when observing elevated MFV. Lindegaard ratio (LR) is commonly used but does not enhance predictive values. We introduce a new marker, the hyperemia index (HI), calculated as bilateral extracranial internal carotid artery MFV divided by initial flow velocity. Methods: We evaluated SAH patients hospitalized ≥7 days between December 1, 2016 and June 30, 2022. We excluded patients with nonaneurysmal SAH, inadequate TCD windows, and baseline TCD obtained after 96 hours from onset. Logistic regression was conducted to assess the significant associations of HI, LR, and maximal MFV with vasospasm and delayed cerebral ischemia (DCI). Receiver operating characteristic analyses were employed to find the optimal cutoff value for HI. Results: Lower HI (odds ratio [OR] 0.10, 95% confidence interval [CI] 0.01‐0.68), higher MFV (OR 1.03, 95% CI 1.01‐1.05), and LR (OR 2.02, 95% CI 1.44‐2.85) were associated with vasospasm and DCI. Area under the curve (AUC) for predicting vasospasm was 0.70 (95% CI 0.58‐0.82) for HI, 0.87 (95% CI 0.81‐0.94) for maximal MFV, and 0.87 (95% CI 0.79‐0.94) for LR. The optimal cutoff value for HI was 1.2. Combining HI <1.2 with MFV improved positive predictive value without altering the AUC value. Conclusions: Lower HI was associated with a higher likelihood of vasospasm and DCI. HI <1.2 may serve as a useful TCD parameter to indicate vasospasm and DCI when elevated MFV is observed, or when transtemporal windows are inadequate. [ABSTRACT FROM AUTHOR]

Background and Purpose: Cerebral small vessel disease is a common manifestation among patients with Fabry disease (FD). As a biomarker of cerebral small vessel disease, the prevalence of impaired cerebral autoregulation as assessed by transcranial Doppler (TCD) ultrasonography was evaluated in FD patients and healthy controls. Methods: TCD was performed to assess pulsatility index (PI) and vasomotor reactivity expressed by breath‐holding index (BHI) for the middle cerebral arteries of included FD patients and healthy controls. Prevalence of increased PI (>1.2) and decreased BHI (<0.69) and ultrasound indices of cerebral autoregulation were compared in FD patients and controls. The potential association of ultrasound indices of impaired cerebral autoregulation with white matter lesions and leukoencephalopathy on brain MRI in FD patients was also evaluated. Results: Demographics and vascular risk factors were similar in 23 FD patients (43% women, mean age: 51 ± 13 years) and 46 healthy controls (43% women, mean age: 51 ± 13 years). The prevalence of increased PI (39%; 95% confidence interval [CI]: 20%‐61%), decreased BHI (39%; 95% CI: 20%‐61%), and the combination of increased PI and/or decreased BHI (61%; 95% CI: 39%‐80%) was significantly (p <.001) higher in FD patients compared to healthy controls (2% [95% CI: 0.1%‐12%], 2% [95% CI: 0.1%‐12%], and 4% [95% CI: 0.1%‐15%], respectively). However, indices of abnormal cerebral autoregulation were not associated independently with white matter hyperintensities and presented a low‐to‐moderate predictive ability for the discrimination of FD patients with and without white matter hyperintensities. Conclusions: Impaired cerebral autoregulation as assessed by TCD appears to be highly more prevalent among FD patients compared to healthy controls. [ABSTRACT FROM AUTHOR]

Background and Purpose: Tuberculous (TB) meningitis is a common type of central nervous system infection, and may cause multifocal cerebral infarctions due to the involvement of cerebral vasculature. This systematic review aims to review and synthesize the utility of transcranial Doppler (TCD) in TB meningitis. Methods: This is a systematic review of observational studies on the use of TCD in patients diagnosed to have TB meningitis. Study outcomes included changes in TCD parameters during stages of TB meningitis, frequency of neurologic complications (such as hydrocephalus, vasculopathy, and cerebral infarction), correlation of TCD findings with neuroimaging, and functional outcomes. Results: Five studies were included with a total of 141 participants, with ages from 4 months to 75 years. The most common neurologic complication was hydrocephalus (87.1%), cerebral infarction (29.2%), and arterial stenosis (26.3%). There was increased mean flow velocity (MFV) most commonly in the middle cerebral artery in the early stage of TB meningitis, and decreased MFV in the advanced disease stage. TCD findings of stenosis were well correlated with CT or MR angiogram. Among patients with hydrocephalus, pulsatility indices were significantly decreased after ventriculoperitoneal shunting. Conclusions: A considerable proportion of patients with TB meningitis develop cerebral hemodynamic disturbances which lead to cerebral ischemia and affect clinical outcomes. TCD is a reliable tool for the diagnosis of vasculopathy and increased intracranial pressure and can thus help monitor disease progression and treatment response. Future studies with larger populations and longer follow‐ups are recommended to determine the association of TCD findings with functional outcomes. [ABSTRACT FROM AUTHOR]

Background and Purpose: Brain death is defined as the irreversible cessation of brain function with a known etiology. This study aims to establish the value of duplex echoencephalography (DEG) in children fulfilling clinical brain death diagnostic criteria. Methods: DEG must show intracranial brain structures. Power Doppler is used to assess venous flow when feasible. Color Doppler patterns in all major arteries are assessed. Spectral analysis of arterial flow is divided into four grades: grade 1: inverted flow during entire diastole with time average peak velocity (TAPV) less or equal to zero; grade 2: disappearance of the inverted diastolic flow at the end of diastole; grade 3: oscillating pattern in early diastole; and grade 4: no diastolic flow with systolic blip. To fulfill diagnosis of brain death, brain perfusion must be lost for 30 minutes. Results: DEG is performed in 41 pediatric patients. In infants, loss of venous flow occurs regardless of the etiology. Grade 1 is the most common arterial color flow pattern and TAPV is always below zero. A pulsatile color flow is associated with three other types of flow patterns (grades 2‐4). TAPV is not calculated, when there is loss of diastolic flow. Diagnosis of brain death is validated using nuclear brain scan in 4 patients. Two have a grade 1 flow pattern, while the other two have a grade 4 flow pattern. Conclusions: In children, DEG following a strict protocol can be used to confirm diagnosis of brain death in the appropriate clinical setting. [ABSTRACT FROM AUTHOR]

Today, it seems prudent to reconsider how ultrasound technology can be used for providing intraoperative neurophysiologic monitoring that will result in better patient outcomes and decreased length and cost of hospitalization. An extensive and rapidly growing literature suggests that the essential hemodynamic information provided by transcranial Doppler (TCD) ultrasonography neuromonitoring (TCDNM) would provide effective monitoring modality for improving outcomes after different types of vascular, neurosurgical, orthopedic, cardiovascular, and cardiothoracic surgeries and some endovascular interventional or diagnostic procedures, like cardiac catheterization or cerebral angiography. Understanding, avoiding, and preventing peri‐ or postoperative complications, including neurological deficits following abovementioned surgeries, endovascular intervention, or diagnostic procedures, represents an area of great public and economic benefit for society, especially considering the aging population. The American Society of Neurophysiologic Monitoring and American Society of Neuroimaging Guidelines Committees formed a joint task force and developed updated guidelines to assist in the use of TCDNM in the surgical and intensive care settings. Specifically, these guidelines define (1) the objectives of TCD monitoring; (2) the responsibilities and behaviors of the neurosonographer during monitoring; (3) instrumentation and acquisition parameters; (4) safety considerations; (5) contemporary rationale for TCDNM; (6) TCDNM perspectives; and (7) major recommendations. [ABSTRACT FROM AUTHOR]

Background and Purpose: Reversible cerebral vasoconstriction syndrome (RCVS) is a syndrome characterized by reversible segmental vasoconstriction of cerebral arteries. Digital subtraction and noninvasive angiograms are typically used to detect vasospasm; however, due to the dynamic nature of RCVS these tests are often negative initially and may need to be repeated multiple times. Transcranial Doppler (TCD) offers many advantages as it is a noninvasive and nonradiating modality. Studies investigating its diagnostic utility for capturing vasospasm and studying temporal evolution of RCVS are limited. Methods: We conducted a retrospective analysis on all patients admitted with suspected RCVS from 2009 to 2014 to a single center at Jackson Memorial Hospital. Results: We identified 9 patients (88.9% women, age 46.6 ± 13.5 years) who met diagnostic criteria for RCVS. All patients presented with headache, 5 developed nonaneurysmal subarachnoid hemorrhage, 5 developed ischemic stroke, and 1 developed posterior reversible encephalopathy syndrome. At initial TCD, 8 patients had increased flow velocities in at least one large intracranial artery and ultimately all patients had abnormal middle cerebral artery flow velocity over the course of RCVS. We found that the number of vessels with abnormal velocities increases gradually and peaks between 13 and 14 days after first symptom onset. Finally, mean flow velocity of affected vessels also increases around the same time frame and normalizes at 60 days. Conclusions: In this case series, we found TCD to be useful in detecting vasospasm and monitoring the temporal evolution of RCVS. TCD could be a helpful clinical tool to diagnose and monitor RCVS. [ABSTRACT FROM AUTHOR]

Background and Purpose: To explore the application value and clinical significance of transcranial Doppler(TCD)in assessing leptomeningeal collateral flow (LMF) status in patients with unilateral middle cerebral artery (MCA) occlusion. Methods: Medical records of patients with unilateral MCA occlusion confirmed by digital subtraction angiography (DSA) were analyzed retrospectively. The patients were divided into three groups according to LMF status, and the laboratory and imaging results were collected. Cerebral blood flow velocity (CBFV) of MCA, anterior cerebral artery (ACA), and posterior cerebral artery (PCA) on the affected side (ipsilateral, i) and the healthy side (contralateral, c) were measured and recorded by TCD. The results of CBFV changes detected by TCD were compared with those of DSA, and the correlation between CBFV changes and LMF status was analyzed. Results: Eighty‐four patients with unilateral MCA occlusion were included. CBFViACA and CBFViPCA were significantly faster than CBFVcACA and CBFVcPCA in patients with good LMF status (p<.05). There was a significant positive correlation between CBFViACA and LMF status (r = 0.697, p<.001). There was statistical significance in receiver operating characteristic curve analysis of CBFViACA and CBFViPCA (p<.05). The area under the curve of CBFViACA and CBFViPCA, respectively, was 0.879 and 0.678, and the best cutoff value was 82 and 60.5 cm/s. Conclusions: TCD can assess LMF status by detecting the changes of flow velocity of intracranial vessels. CBFV of ACA and PCA in patients with MCA occlusion is significantly correlated with LMF status by DSA. Assessing LMF status, CBFViACA, CBFViACA/CBFVcACA, and CBFViACA/CBFViMCA has the great diagnostic value, which is of great significance in guiding MCA occlusion patients to choose individualized treatment. [ABSTRACT FROM AUTHOR]

Cerebral vessel recanalization therapy, either intravenous thrombolysis or mechanical thrombectomy, is the main treatment that can significantly improve clinical outcomes after acute ischemic stroke. The degree of recanalization and cerebral reperfusion of the ischemic penumbra are dependent on cerebral hemodynamics. Currently, the main imaging modalities to assess reperfusion are MRI and CT perfusion. However, these imaging techniques cannot predict reperfusion‐associated complications and are not readily available in many centers. It is also not feasible to repeat them frequently for sequential assessments, which is important because of the changing nature of cerebral hemodynamics following stroke. Transcranial Doppler sonography (TCD) is a valid, safe, and inexpensive technique that can assess recanalized vessels and reperfused tissue in real‐time at the bedside. Post thrombectomy reocclusion, hyperperfusion syndrome, distal embolization, and remote infarction result in poor outcomes after mechanical or intravenous reperfusion therapy. Managing blood pressure following these endovascular treatments can also be a dilemma. TCD has an important role, with major clinical implications, in evaluating cerebral hemodynamics and collateral vessel status, guiding clinicians in making individualized decisions based on cerebral blood flow during acute stroke care. This review summarizes the most relevant literature on the role of TCD in evaluating patients after reperfusion therapy. We also discuss the importance of performing TCD in the first few hours following thrombolytic therapy in identifying hyperperfusion syndrome and embolic signals, predicting recurrent stroke, and detecting reocclusions, all of which may help improve patient prognosis. We recommend TCD during the hyperacute phase of stroke in comprehensive stroke centers. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: Investigation for patent foramen ovale (PFO) is warranted in patients with cryptogenic stroke (CS), as PFO closure is recommended in select CS patients for secondary stroke prevention. Transcranial Doppler (TCD) is noninvasive and has high sensitivity for PFO screening. However, 10% of the population has insufficient temporal bone windows to perform standard TCD monitoring of the middle cerebral arteries (MCAs). Prior reports showed similar diagnostic accuracy between the basilar artery and MCAs insonation. Our objective was to assess the accuracy of transforaminal insonation of the basilar artery (TIBA) in diagnosis of right‐to‐left shunt (RLS) in patients with inadequate temporal windows. METHODS: We performed a retrospective, single‐center, observational study of TIBA in patients with CS and inadequate temporal windows. We compared the PFO screening accuracy using TIBA versus echocardiogram, either transthoracic (TTE) or transesophageal echocardiogram (TEE). RESULTS: Sixteen females and four males were included (mean age 63.2). All patients underwent TTE, 10 (50%) underwent gold‐standard TEE. Nine patients had positive PFO with both TCD and echocardiogram. Two patients with negative echocardiogram had TCD‐positive shunt. Three patients had PFO present on echocardiogram, whereas TCD was negative. Six patients had absent shunt with both TCD and echocardiogram. The sensitivity and specificity of TIBA for RLS detection were 75%, positive predictive value 82%, and negative predictive value 67%. CONCLUSION: PFO screening accuracy using TIBA was 75%. Prospective evaluation of CS patients with TIBA and comparison to the gold‐standard TEE should be performed to further guide clinical practice. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: Patients with acute ischemic stroke receive computed tomography angiogram (CTA) and digital subtraction angiogram (DSA) for clinical evaluation. Current guidelines lack in defining indications for transcranial Doppler (TCD) and/or carotid duplex ultrasonography (CUS) in acute stroke evaluation or follow‐up cerebrovascular imaging after reperfusion. We investigated the clinical utility of performing additional TCD/CUS after reperfusion in guiding postacute care stroke management. METHODS: Retrospective review of acute ischemic stroke patients admitted to a comprehensive stroke center with CTA head and neck and/or DSA followed by TCD/CUS. Cases were reviewed by two authors to determine if TCD/CUS provided additional diagnostic information to aid management. A nominal group process, using a third author, achieved consensus in cases of disagreements. RESULTS: Only 25 of 198 patients had CTA or DSA followed by TCD/CUS. Ten (40%) cases showed new clinical information from CUS aiding management. Of those with TCD, 5 patients (22.7%) had findings that impacted management. These clinical scenarios included detection of mobile thrombus requiring anticoagulation; distinguishing carotid near‐occlusion from occlusion; confirming hemodynamic significance of intra/extracranial stenosis helping emergent stenting/endarterectomy; detecting hyperperfusion on TCDs causing symptoms; and establishing chronicity of carotid stenosis based on collateral flow patterns, which deferred further intervention. DISCUSSION: Our experience shows that TCD/CUS may offer additional diagnostic information assisting postacute care management in small subset of patients with acute ischemic stroke. Larger studies are needed to research the clinical impact and cost‐effectiveness of additional imaging and inform clinical guidelines for selecting patients who will benefit from these additional studies. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: The breath‐holding index (BHI) is a useful method to assess cerebrovascular reactivity. It is calculated based on the mean flow velocities of the middle cerebral artery (MCA) using transcranial Doppler (BHIMCA). Therefore, it is not feasible in patients with poor temporal windows. This study tested the feasibility of a BHI using the internal carotid artery (ICA) siphon flow velocity (BHIICA). METHODS: Twenty‐four patients (aged 38‐79 years) with unilateral or bilateral stenosis of the cervical ICAs were prospectively recruited. The 48 examined bilateral ICAs were divided into three groups according to the stenosis degree: <50%, 50‐99%, and occlusion. We investigated the reproducibility of both BHI methods (BHIMCA and BHIICA), the correlation between the two BHI methods, and the tendency for the BHIs to decrease with increasing degree of cervical ICA stenosis. RESULTS: For the BHIMCA, we found a good reproducibility (intraclass correlation coefficient, rI >.9) and a significantly decreased BHI with increasing stenosis of the ICA (P =.001). For the BHIICA, good reproducibility was demonstrated (rI > or ≒.9), but there was no significant decrease in the BHI related to the increasing degree of ICA stenosis (P =.952). Furthermore, the correlation between the two BHI methods was not robust (kappa coefficient, right.259; left.619). CONCLUSIONS: Our study suggests that the BHIICA is not a feasible alternative method to the BHIMCA. [ABSTRACT FROM AUTHOR]

Background and Purpose: Ischemic stroke can occur in 20-55% of patients with infective endocarditis (IE) with 75% occurring during the first 2 weeks of treatment. CT or MRI brain can diagnose the sequelae of stroke but transcranial Doppler (TCD) can document active embolization. We undertook a retrospective review of our patient cohort and a systematic review of literature to assess the role of TCD in early diagnosis and management of ischemic stroke in IE.Methods: Retrospective chart review and literature review.Results: We found 89 patients with stroke caused by IE at our institution from December 2011 to April 2018. TCDs were obtained on 26 patients; 16 were abnormal for cerebrovascular abnormalities. Only 4 patients had 30-minute emboli monitoring performed, of which one revealed emboli. We found 3 studies investigating the role of TCDs in IE that showed promise in its use as a predictive tool in stroke risk stratification.Conclusions: Presence of embolization in the form of high-intensity transient signals (HITS) detected on TCDs can be used for early diagnosis of IE, assessing efficacy of antibiotic therapy, and stratification of stroke risk in IE. This can aid further research into testing preventative interventions for reducing stroke burden in IE such as earlier valvular surgery or vacuum-assisted vegetation extraction. [ABSTRACT FROM AUTHOR]

Background and Purpose: Pulsatility index (PI) in the middle cerebral artery (MCA) is considered a measure of peripheral vascular resistance. Several established cardiovascular risk factors are common for both MCA PI and carotid atherosclerosis. Accordingly, in the present study we hypothesized an association between ultrasound-derived indices of carotid atherosclerosis and MCA PI.Methods: All residents in Akershus County, born in 1950, were invited to a cardiovascular examination, The Akershus Cardiac Examination (ACE) 1950 Study (2012-2015). A thorough ultrasound examination was performed to assess indices of atherosclerosis in the carotid arteries, and PI in the MCAs. In all, 3154 (85.1%) had adequate transcranial and carotid data. Associations between indices of carotid atherosclerosis and MCA PI were assessed by regression analyses adjusted for established cardiovascular risk factors.Results: Mean age was 64 (standard deviation [SD]: .6) years, and 1,357 (43%) were women. Mean MCA PI was .97 (SD: .17). Participants in the upper quartile of MCA PI had higher pulse pressure, more frequently hypertension, diabetes mellitus, and a history of coronary artery disease. Both carotid plaque score (B .007 [95% CI: .003-.010]) and carotid intimamedia thickness (B .173 [95% CI: .120-.226]) were significantly associated with MCA PI in adjusted analysis. The model R2 was .055.Conclusion: In a population-based sample of middle-aged adults, ultrasound-derived indices of carotid atherosclerosis were independently associated with MCA PI. However, the overall explained variance of MCA PI was low, suggesting other factors than atherosclerosis and cardiovascular risk factors to play an important role for MCA PI. [ABSTRACT FROM AUTHOR]

Background and Purpose: Microembolic signals (MES) are detectable by transcranial Doppler monitoring and associated with increased risk of first or recurrent ischemic stroke. MES detection can also illuminate stroke etiology and the effect of prophylactic treatment. MES detection cannot accurately distinguish between stroke-related microemboli and ultrasound contrast agents. These agents contain microbubbles and are frequently used in neuro- and cardiovascular diagnostics. We aimed to assess how long after contrast infusion microbubbles are detectable by transcranial Doppler monitoring.Methods: Ten healthy volunteers received an intravenous infusion of stabilized sulfur hexafluoride microbubbles (SonoVue®) for 30 minutes. The infusion was followed by continuous unilateral Doppler monitoring (TCD-X, Atys Medical, Soucieu-en-Jarrest, France) for 3.5 hours.Results: MES persisted for 12 to 77 minutes (median 40.5 minutes), and the frequency tended to decrease gradually until cessation.Conclusions: None of the subjects had detectable MES for more than 77 minutes after ultrasound contrast infusion. MES detection with the intent to detect stroke-related microemboli should wait for at least this long after completed infusion. [ABSTRACT FROM AUTHOR]

Background and Purpose: Transcranial Doppler (TCD) criteria for cerebrovascular stenosis are only based on velocity with unsatisfactory positive predictive value (PPV) in previous studies. We refined a published scoring system that integrates several characteristics of TCD data in diagnosing middle cerebral artery (MCA) stenosis.Methods: Using the TCD-digital subtraction angiography (DSA) database from Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial, velocity, spectrum pattern, diffuse ratio, and asymmetry ratio were assessed. The cutpoints were defined for each parameter and a point value was assigned to each category within that parameter. A summed score was calculated for each MCA. The accuracy was assessed for different cutpoints in predicting ≥50% MCA stenosis measured by DSA. Logistic regression and C-statistics were used for analysis.Results: A total of 114 MCAs were included in vessel-based and 87 patients were included in patient-based analysis. Compared to the velocity-only cutpoints in SONIA, the score results in much improved PPV while negative predictive value (NPV) remains unchanged. The score based on mean velocity (score 0: <140 cm/s, score 3: ≥140 cm/s), spectrum pattern (score 0: no turbulence; score 1: mild turbulence; 2: significant turbulence), and asymmetry ratio (score 0: ratio <1.5, score 1: ratio 1.5-2; score 2: ratio ≥2.1) has the highest NPV while PPV remains favorable (PPV: 72% [95% CI 54-90%]; NPV: 84% [95% CI: 75-93%], area under curve [AUC]: .76 [95% CI: .66-.86]).Conclusions: The multiparameter scoring system incorporating several characteristics of TCD measures yielded higher PPV while maintaining high NPV compared with the single-parameter velocity criteria in diagnosing MCA ≥50% stenosis. [ABSTRACT FROM AUTHOR]

Acute multi-territory, embolic cerebral infarctions are often associated with serious underlying clinical conditions including the presence of highly "active" emboligenic sources causing that in turn may result in high early recurrence rates. Prompt diagnosis, risk stratification, and treatment are substantial for the prevention of subsequent embolization that would result in further clinical deterioration. Among other clinical investigations, transcranial Doppler (TCD) monitoring is highly efficacious for the detection of microembolic signals (MES) that correspond to microthrombi entering the intracranial circulation. The presence and burden of MES, especially in multiple intracranial arteries, is clearly associated with an increased risk of symptomatic, recurrent embolization, and thus can justify a more aggressive treatment approach (clopidogrel load followed by dual antiplatelet therapy or alternatively therapeutic dose of low-molecular-weight heparin). In this narrative review, we discuss the most important causes of multi-territory embolic ischemic strokes and also underscore the utility of TCD as a noninvasive tool for the diagnosis, risk stratification, and treatment. [ABSTRACT FROM AUTHOR]

Carotid artery disease (CAD) is a common cause of ischemic stroke with high rates of recurrence. Carotid endarterectomy (CEA) or carotid artery stenting (CAS) are highly recommended for the secondary prevention of symptomatic CAD during the first 14 days following the index event of transient ischemic attack or minor stroke. CEA or CAS may also be offered in selected cases with severe asymptomatic stenosis. Herein, we review the utility of neurosonology in the diagnosis and pre-/peri-interventional assessment of CAD patients who undergo carotid revascularization procedures. Carotid ultrasound may provide invaluable information on plaque echogenicity, ulceration, risk of thrombosis, and rupture. Transcranial Doppler or transcranial color-coded sonography may further assist by mapping collateral circulation, evaluating the impairment of vasomotor reactivity, detecting microembolization, or reperfusion hemorrhage in real time. Neurosonology examinations are indispensable bedside tools assisting in the diagnosis, risk stratification, peri-interventional monitoring, and follow-up of patients with CAD. [ABSTRACT FROM AUTHOR]

Background and Purpose: Extracerebral venous congestion can precipitate intracranial hypertension due to obstruction of cerebral blood outflow. Conditions that increase right atrial pressure, such as hypervolemia, are thought to increase resistance to jugular venous outflow and contribute to cerebro-venous congestion. Cerebral pulsatility index (CPI) is considered a surrogate marker of distal cerebrovascular resistance and is elevated with intracranial hypertension. Thus, we sought to test the hypothesis that elevated right atrial pressure is associated with increased CPI compared to normal right atrial pressure.Methods: We retrospectively reviewed 61 consecutive patients with subarachnoid hemorrhage. We calculated CPI from transcranial Doppler studies and correlated these with echocardiographic measures of right atrial pressure. CPIs were compared from patients with elevated and normal right atrial pressure.Results: There was a significant difference between CPI obtained from all patients with elevated right atrial pressure compared to those with normal right atrial pressure (P < .0001). This finding was consistent in sensitivity analysis that compared right and left hemispheric CPI from patients with both elevated and normal right atrial pressure.Conclusion: Patients with elevated right atrial pressure had significantly higher CPI compared to patients with normal right atrial pressure. These findings suggest that cerebro-venous congestion due to impaired jugular venous outflow may increase distal cerebrovascular resistance as measured by CPI. Since elevated CPI is associated with poor outcome in numerous neurological conditions, future studies are needed to elucidate the significance of these results in other populations. [ABSTRACT FROM AUTHOR]

Background: Poststroke vascular cognitive impairment is highly prevalent with significant functional consequences. However, reliable biomarkers for early prediction of cognitive decline after acute ischemic stroke (AIS) are not well established. Although parenchymal imaging in patients with AIS and transient ischemic attack (TIA) may predict the resultant cognitive impairment, it may not explain the progressive deterioration after the index event. We postulated that longitudinal changes in cerebral hemodynamic parameters may influence the cognitive performance after a cerebrovascular event.Methods: One-hundred consecutive AIS/TIA patients were recruited within 2 weeks following a cerebrovascular event. At 3-6 months, 69 patients were followed up with transcranial Doppler (TCD) and brief cognitive tests (Mini-Mental State Examination [MMSE]/Montreal Cognitive Assessment [MoCA]). Basic demographics, vascular risk factors, clinical, cognitive, and neurological status were recorded.Results: Considerable proportion (12%) of patients showed cognitive decline and changes in the hemodynamic parameters over 3-6 months after the index event. We showed that right middle cerebral artery (MCA) stenosis and right internal carotid artery/MCA tandem lesions at 3-6 months are associated with the change in the MMSE scores. Additionally, there was a trend toward association between increased pulsatility index of the right MCA and a decline in the MMSE score. However, we did not observe any association between cognitive decline and longitudinal changes in hemodynamic parameters.Conclusion: Although hemodynamic parameters deteriorate in a considerable proportion of patients during first 3-6 months after a cerebrovascular event, cognitive decline appears to be an independent phenomenon. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to describe in detail the characteristics and accreditation compliance of laboratories in the United States applying for Intersocietal Accreditation Commission (IAC) transcranial Doppler (TCD) accreditation.Methods: This was a retrospective study of all applicant laboratories from 2012 to 2015. We used the IAC database to extract laboratory characteristics and guideline compliance metrics.Results: Evaluation of 97 laboratories demonstrated that 67% were hospital-based and located in the South (43.3%), corresponding to the location of "Stroke Belt" states. Cases from 186 interpreting physicians, of which 110 (59%) were neurologists, were evaluated during the accreditation process. Established practice was the most common training pathway (54.8%), and a majority had not obtained an additional vascular interpretation credential (72.6%). From 318 case studies, the most frequent indications were subarachnoid hemorrhage (31.0%), stroke (17.0%), and carotid stenosis (14.3%). Although most laboratories had been previously accredited, accreditation was delayed for 77.3% due to incomplete studies (33.0%), discrepant findings between the report and the laboratory's diagnostic criteria (23.7%), and discrepant findings between the report and the waveforms/images (17.5%).Conclusions: The results suggest that there are significant differences between IAC applicant laboratories and laboratories represented by Centers for Medicaid and Medicare Services (CMS) claims data. In addition, accurate study reporting, physician training, and ongoing quality improvement activities may not be optimized in laboratories applying for accreditation. With the information learned from this study, educational strategies by professional organizations, including the IAC, can be tailored to help improve TCD practice. [ABSTRACT FROM AUTHOR]

The subclavian-vertebral artery steal syndrome (SSS) is the hemodynamic phenomenon of blood flow reversal in the vertebral artery due to significant stenosis or occlusion of the proximal subclavian artery or the innominate artery. Occasionally, SSS is diagnosed in patients not harboring arterial stenosis. With the exception of arterial congenital malformations, the limited case reports of SSS with intact subclavian artery are attributed to dialysis arteriovenous fistulas (AVFs). Interestingly, these cases are more frequently symptomatic than those with the classical atherosclerotic SSS forms. On the other hand, the disclosure of SSS due to subclavian/innominate artery atherosclerotic stenosis, even in the absence of accompanying symptoms, should prompt a thorough cardiovascular work-up for the early detection of coexisting coronary, carotid, or peripheral artery disease. Herein, we review the incidence, clinical presentation, sonographic findings, and therapeutic interventions related to SSS with and without subclavian/innominate artery stenosis. We also review the currently available data in the literature regarding the association of SSS and dialysis AVF. In addition, we present a patient with bilateral symptomatic SSS as the result of an arteriovenous graft (AVG) that was introduced after the preexisting AVF in the contralateral arm became nonfunctional. SSS due to subclavian or innominate artery stenosis/occlusion is rarely symptomatic warranting interventional treatment. In contrast, when it is attributed to AVF, surgical correction is frequently necessary. [ABSTRACT FROM AUTHOR]

Background: In order to differentiate between the different causes of intracranial stenosis, we compared the diagnostic results of transcranial color-coded duplex (TCCD) sonography with the recently developed 3D high-resolution black blood MR sequence.Methods: We studied retrospectively 20 patients referred to our hospital after acute ischemic stroke who were diagnosed with intracranial stenosis and in whom a repetitive TCCD and a 3D MR T1 FAT SAT (black blood) sequence at 3T (TR/TE 350/20 ms, FOV 160×182×120 mm, 0.4×0.4×0.4 size of pixel, 300 slices, Fat Sat spair, acquisition time 6 minutes 14) were performed. Etiological diagnosis was based on one hand on the morphological aspect of the arterial wall (black blood T1 FAT SAT sequence) and on the hemodynamic aspect (TCCD) on the other hand. Analysis of black blood T1 FAT SAT MR sequence and TCCD agreement on the etiological diagnosis was performed using sign test.Results: TCCD was performed at admission and at least at two different intervals during follow-up. Eleven patients had diffuse intracranial arterial disease and nine had involvement of a single intracranial artery. Etiology of intracranial arterial stenosis included: atheromatosis, thrombosis, vasculitis and reversible vasoconstriction syndrome. There was 80% agreement (sign test P = .0059) between these two methods.Conclusions: These two combined imaging techniques might be promising for the differentiation of arteriosclerotic changes from stenosis of another origin, especially when follow-up TCCD studies are completed early before a possible regression of the atherosclerotic plaque that might be observed 6 months after initial diagnosis. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND AND PURPOSE Whether hemodynamic and/or embolic transcranial Doppler (TCD) features of internal carotid artery (ICA) stenosis contribute to the classification of stroke patterns on MRI. PATIENTS AND METHODS Consecutive patients presenting symptomatic ≥50% ICA stenosis were included. Microembolic signals (MES) detection and measurement of cerebral vasoreactivity (VR) were performed by TCD. Only acute MRI lesions, territorial (TT) and/or borderzone (BZ) were considered. RESULTS A total of 72 ICA stenoses, 27 (38%) moderate (50-69%), and 45 (62%) high grade (70-99%) were included. MRI lesions showed 32 (44%) pure TT, 20 (28%) pure BZ, and 20 (28%) mixed TT and BZ. Impaired VR was found more frequently among patients with higher degrees of stenoses ( P < .001) whereas MES were similarly encountered in both groups ( P = NS). Impaired VR was more common in the BZ (10/20, 50%) than in the TT group (9/32, 28%, P < .1) while MES were present in 47% (15/32) of patients with TT and in 30% (6/20, P < .1) of those with BZ lesions, in particular in cortical BZ infarcts ( P < .02). CONCLUSION Our findings suggest that TCD characteristics of the ICA stenosis contribute to better define stroke patterns on MRI in about one-third of the patients presenting with pure TT or BZ lesions. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND Transcranial Doppler (TCD) ultrasonography is a noninvasive bedside tool that can evaluate cerebral blood flow hemodynamics in major intracranial arteries. TCD-derived pulsatility index (PI) is believed to be influenced by intracranial pressure (ICP). OBJECTIVE To correlate TCD-PI with cerebrospinal fluid (CSF) pressure (representing ICP), measured by standard lumbar puncture (LP) manometry. METHODS CSF pressures (CSF-P) were measured in 78 patients by LP manometry. Stable TCD spectra were obtained 5 minutes before LP from either middle cerebral arteries using Spencer's head frame and 2-MHz transducer. PI values were calculated from the TCD spectra by an independent neurosonologist. RESULTS Factors displaying a significant relationship with CSF-P included age ( R = −.426, P < .0005); EDV ( R = −.328, P = .002;) and PI ( R = .650, P < .0005). On analyzing dichotomized data (CSF-P < 20 vs. ≥ 20 cm H20) TCD-PI was an independent determinant (OR per .1 increase in PI = 2.437; 95% CI, 1.573-3.777; P < .0005). PI ≥ 1.26 could reliably predict CSF-P ≥ 20 cm H20 (sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were 81.1%, 96.3%, 93.8%, 88.1%, and 90.1% respectively). CONCLUSION TCD-derived PI could be used to identify patients with CSF-P ≥ 20 cm H20 and may play an important role as a monitoring tool. [ABSTRACT FROM AUTHOR]

ABSTRACT OBJECTIVES To assess the evidence on the safety and efficacy of sonothrombolysis in acute stroke. SEARCH METHODS Electronic databases and grey literature were searched under different MeSH terms from 1970 to present. SELECTION CRITERIA Randomized control trials (RCTs) and case control studies (CCSs) on sonolysis and sonothrombolysis alone or with microsphere in acute stroke patients (>18 old). Outcome measures included complete recanalization (CR) at 1-2 and 24 hours, 3 months modified Rankin Scale (mRS), and symptomatic intracerebral hemorrhage (sICH). Data was extracted to Review Manager software. RESULTS Fifty-seven studies were retrieved and analyzed. Ten studies (7 RCTs and 3 CCSs) were included in our meta-analysis, which revealed that sonolysis and sonothrombolysis are safe (OR of sICH: 1.14; 95% confidence interval (CI): 0.56- 2.34;P=0.71) and effective (OR of CR at 1-2 hours: 2.95;95% CI: 1.81-4.81;P<0.00001) and have more than two-fold higher likelihood of favourable long-term outcome (3-month mRS 0-2; OR: 2.20; CI:1.52-3.19;P<0.0001). Further subgroup analysis based on the presence of microsphere revealed that it is safe (OR of sICH: 1.18; CI:0.433.24;P=0.75) and effective (OR of CR: 2.61; CI: 1.36-4.99;P=0.004). Subgroup analysis based on sonolysis revealed to be safe and effective. CONCLUSIONS This novel treatment appears safe and effective. The evidence of microsphere as an enhancement of sonothrombolysis is evolving. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND AND PURPOSE Although transesophageal echocardiography (TEE) is the gold standard for right to left shunt detection, we observed that transcranial Doppler (TCD) was more sensitive and sought an explanation. METHODS We retrospectively evaluated results of TCD and TEE in 118 patients with cryptogenic stroke and transient ischemic attacks. TCDs were done as per modification of a published performance protocol and interpreted by a neurologist and radiologist. TEEs were performed and interpreted by five cardiologists without standardized protocol. Statistical methodology included χ2 tests, Fisher exact tests, and ANOVA. RESULTS Overall agreement between TCD and TEE was found for 76 of 118 patients. Sensitivities of TCD and TEE were 93.8% and 53.1%. Sensitivities for TCD interpreters were 61.1% and 64.1%. Sensitivities for TEE operators varied from 46.7% to 75.7%. We were unable to find a performance protocol for TEE microbubble studies in either published literature or certification organizations. CONCLUSIONS TEEs and TCDs are operator dependent and thus subject to false negatives. The lower yield and interoperator variability in TEE results appear to reflect the lack of performance protocols and engender concern about false negatives in community use. Consensus performance protocols and certification criteria for both modalities should have an impact on accuracy of shunt detection. [ABSTRACT FROM AUTHOR]

ABSTRACT In patients with critical carotid stenosis and ischemic stroke, it is crucial to determine whether distal hypoperfusion or artery-to-artery embolism is the predominant mechanism. The role of transcranial doppler (TCD) in this setting is vital. We report a patient with fibromuscular dysplasia and recurrent orthostatic transient ischemic attacks where fall in cerebral perfusion was clearly demonstrated by TCD. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND Transcranial Doppler (TCD) has been subjected to criticism for detecting vasospasm (VSP). Our study's aim is to derive criteria for middle cerebral artery (MCA) vasospasm (MCA-VSP) based on cerebral angiography (CA). METHODS A prospective data of patients with aneurysmal subarachnoid hemorrhage (aSAH) from January 2004 to August 2009. TCD was performed daily from day 2 to 14 from symptom's onset. Follow-up CA was done at day 7-9. TCD mean flow velocities (MFV) of all vessels at baseline (b), middle (m) and before CA (preangio) were recorded. Several MCA MFV ratios were computed. Moderate to severe VSP on CA was defined as >1/3 luminal narrowing. Univariate and stepwise logistic regression analysis were performed. RESULTS One hundred sixty-nine patients (338 MCA) with aSAH were included, mean age: 54.8 ± 13, women: 103 (62%). Twenty-nine patients (8.6%) had angiographic MCA-VSP. TCD scoring system of 3 points for MCA-VSP was computed based on (a) bMCA MFV ≥ 120 cm/s (sensitivity: 59.3%, specificity: 85%, PPV: 36.4%, NPV: 93.5%, P < .001) (1 point), Preangio MCA MFV ≥ 150 cm/s (79.3%, 89.9%, 39%, 97.3%, <.001) (1 point), and affected preangio MCA/bMCA MFV ratio ≥1.5 (84%, 63%, 25.6%, 96.3%, .001) (1 point). The score of 3 has 96% sensitivity and 96% specificity (OR: 300) whereas the score of 1 has 12% sensitivity and 58% specificity (OR: 4.3) for identifying MCA-VSP. CONCLUSION TCD stringent criteria for moderate to severe MCA-VSP are feasible and applicable in aSAH population. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND Transcranial Doppler (TCD) ultrasonography has been extensively used in the evaluation and management of patients with cerebrovascular disease since the clinical application was first described in 1982 by Aaslid and colleagues TCD is a painless, safe, and noninvasive diagnostic technique that measures blood flow velocity in various cerebral arteries. Numerous commercially available TCD devices are currently approved for use worldwide, and TCD is recognized to have an established clinical value for a variety of clinical indications and settings. Although many studies have reported normal values, there have been few recently, and none to include a large cohort of healthy subjects across age, race, and gender. As more objective, automated processes are being developed to assist with the performance and interpretation of TCD studies, and with the potential to easily compare results against a reference population, it is important to define stable normal values and variances across age, race, and gender, with clear understanding of variability of the measurements, as well as the yield from various anatomic segments. METHODS To define normal TCD values in a healthy population, we enrolled 364 healthy subjects, ages 18-80 years, to have a complete, nonimaging TCD examination. Subjects with known or suspected cerebrovascular disorders, systemic disorders with cerebrovascular effects, as well as those with known hypertension, diabetes, stroke, coronary artery disease, or myocardial infarction, were excluded. Self-reported ethnicity, handedness, BP, and BMI were recorded. A complete TCD examination was performed by a single experienced sonographer, using a single gate nonimaging TCD device, and a standardized protocol to interrogate up to 23 arterial segments. Individual Doppler spectra were saved for each segment, with velocity and pulsatility index (PI) values calculated using the instrument's automated waveform tracking function. Descriptive analysis was done to determine the mean velocities and PI, and all data were analyzed for changes by decade of age, sex race, handedness, BMI, and BP. RESULTS Among the key intracranial segments, mean blood flow velocities (MBFV) were highest in the MCA and lowest in the PCA across all ages, sexes, and ethnic groups. There was no difference in the MBFVs between left and right side segments of the Circle of Willis, with the exception of the distal M1 ( P= .022) and the C1 ( P < .0001), both slightly higher on the left. MBFV were higher among women than men in all segments except for the OA. MBFV decreased with advancing age in both men and women, but this was specific to Caucasian subjects. There were lower velocities in the OA for non-Caucasians. The PI was lower in the left VA ( P < .0001), and for most segments was lower in women than men. The PI increased with age in all segments for women, but only in some segments for men, and this finding was also specific to Caucasian subjects. The yield of usable data ranged from 99.7% for the VA and BA, to 88.2% for C2. CONCLUSION Our study provides normal, reference TCD values for a large cohort of healthy subjects across a wide range of age, sex, and race groups. We observed decreased MBFV and increased PI with aging, and higher MBFV in women. There were few differences in MBFV related to side or ethnicity, but the MFBV and PI changes with age were specific to Caucasians. We provide means and standard deviations of MBFVs across various demographic groups in key intracranial arteries. Such normal TCD values across age, gender, and ethnic groups in healthy subjects represent a useful reference tool for detecting individuals with TCD values outside normal limits and at increased vascular risk. TCD studies in large multiethnic populations are still required to determine differences in brain hemodynamics across various ethnic groups. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND Age-related white matter changes (WMC) increase risk of cognitive and functional decline. They are considered as target for preventive trials. However, using magnetic resonance imaging (MRI) to screen for subclinical WMC is not cost-effective. We explored the clinical utility of transcranial Doppler ultrasound (TCD) in the evaluation of WMC. We hypothesized that the pulsatility index (PI) of TCD correlates with severity of WMC. METHODS Among 100 stroke patients with WMC, we obtained the mean PI of middle cerebral artery (MCA) and vertebral basilar artery (VB). We investigated the association between PI and WMC volume. We also obtained PI of 50 subjects who had no WMC on MRI and explored the ability of PI values in differentiating subjects with and without WMC. RESULTS Multivariate linear regressions found that mean MCA PI and mean VB PI were independent predictors for total WMC volume (beta = .43, P < .001 and beta = .37, P < .001, respectively). Mean MCA PI significantly differentiated patients with WMC from those without WMC (area under curve [AUC] .85 [95% confidence interval .78-.91]) with an optimal cut-off value at 1.15 that yielded sensitivity and specificity of 73.7% and 82%, respectively. AUC for mean VB PI was .81 (95% confidence interval .74-.88) with cut-off value at 1.06 that yielded sensitivity and specificity of 70% and 75%, respectively. CONCLUSIONS PI correlates with volume of WMC. It may help to differentiate those with and without WMC in stroke patients. Further study evaluating the clinical utility of TCD in screening for subclinical WMC among community elderly is warranted. [ABSTRACT FROM AUTHOR]

ABSTRACT BACKGROUND AND PURPOSE Transcranial Doppler (TCD) and near-infrared spectroscopy (NIRS) are two noninvasive diagnostic tools that have been shown to evaluate cerebral vasomotor reactivity by measuring changes in mean cerebral blood flow velocities (MCBFV) of proximal intracranial arteries and absolute brain-tissue oxygen-saturation (TOS) in microcirculation, respectively, during hemodynamic challenge. We evaluated the potential correlation between TCD and NIRS measurements of vasomotor reactivity (VMR) in patients with carotid artery disease (CARAD). METHODS Consecutive patients ( n = 24) with CARAD underwent simultaneously TCD and NIRS examinations during voluntary breath-holding (BH). MCBFV and TOS values were recorded at baseline (BAS) and at the end of BH, while BH duration (DBH) was documented. VMR was quantified by means of TCD-BHI (Breath-holding Index: [MCBFVBH− MCBFVBAS]× 100/MCBFVBAS/DBH) and NIRS-BHI ([TOSBH− TOSBAS]× 100/ TOSBAS/DBH). RESULTS TCD-BHI correlated positively with NIRS-BHI in the affected side ( r = .538, P = .007). A stronger correlation between TCD-BHI and NIRS-BHI was documented in the nonaffected side ( r = .768, P< .001). After adjusting for demographic characteristics, stroke risk factors and symptomatic status NIRS-BHI was linearly and independently associated with TCD-BHI both in the affected (β:+ .813, P = .001) and unaffected (β:+ .823, P < .001) side. CONCLUSIONS Circulatory assessment of VMR in proximal cerebral vessels by TCD correlates positively to functional measurements of VMR in microcirculation by NIRS in CARAD patients. [ABSTRACT FROM AUTHOR]

The American Society of Neurophysiologic Monitoring (ASNM) and American Society of Neuroimaging (ASN) Guidelines Committees formed a joint task force and developed guidelines to assist in the use of transcranial Doppler (TCD) monitoring in the surgical and intensive care settings. Specifically, these guidelines: (1) delineate the objectives of TCD monitoring; (2) characterize the responsibilities and behaviors of the sonographer during monitoring; (3) describe methodological and ethical issues uniquely relevant to monitoring. The ASNM and ASN strongly support the positions that (1) acquisition and interpretation of intraoperative TCD ultrasonograms be performed by qualified individuals, (2) service providers define their diagnostic criteria and develop on going self-validation programs of these performance criteria in their practices. We agree with the guidelines of other professional societies regarding the technical and professional qualifications of individuals responsible for TCD signal acquisition and interpretation (Class III evidence, Type C recommendation). On the basis of current clinical literature and scientific evidence, TCD monitoring is an established monitoring modality for the: (1) assessment of cerebral vasomotor reactivity and autoregulation; (2) documentation of the circle of Willis functional status; (3) identification of cerebral hypo- and hyperperfusion, recanalization and re-occlusion; and (4) detection of cerebral emboli (Class II and III evidence, Type B recommendation). [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE: Transcranial Doppler (TCD) is often used as a screening tool for detecting intracranial stenosis. Since TCD results may vary among laboratories and sonographers, it requires validation against an imaging modality. We evaluated diagnostic accuracy of TCD performed in our laboratory against time-of-flight (TOF) magnetic resonance angiography (MRA) in detecting intracranial stenosis in patients with acute cerebral ischemia. METHODS: Consecutive patients with acute (<24 hours) cerebral ischemia and intracranial arterial stenosis on MRA underwent both TCD and MRA within 5 hours of each other. TCD was performed by credentialed neurosonologists according to standardized protocol. An independent neuroradiologist interpreting MRA was blinded to TCD findings. We evaluated TCD peak systolic velocities (PSV) in proximal intracranial arteries as predictive of moderate (>50%) and severe (>70%) stenosis on TOF-MRA. RESULTS: One hundred and fifty patients (74% males; mean age 53 years) underwent neurovascular evaluation with TCD and MRA. Twenty-two (14.6%) patients were excluded due to absent temporal acoustic windows. Middle cerebral artery TCD PSV values of >140 cm/s and >180 cm/s were found to predict a >50% and >70% focal stenosis, respectively. Optimal cutoff PSV values for other major proximal intracranial arteries were also established. CONCLUSIONS: TCD performed in our laboratory shows satisfactory agreement with TOF-MRA in diagnosis and grading of proximal intracranial stenosis in patients with acute cerebral ischemia. [ABSTRACT FROM AUTHOR]

Background: Changes in partial pressure of carbon dioxide (PaCO2) are associated with a decrease in cerebral blood flow (CBF) during hypocapnia and an increase in CBF during hypercapnia. However, the effects of changes in PaCO2 on cerebral arterial compliance (Ca) are unknown. METHODS: We assessed the changes in Ca in 20 normal subjects using monitoring of arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). Cerebral arterial blood volume (CaBV) was extracted from CBFV. Ca was defined as the ratio between the pulse amplitudes of CaBV (AMPCaBV) and ABP (AMPABP). All parameters were recorded during normo-, hyper-, and hypocapnia. RESULTS: During hypocapnia, Ca was significantly lower than during normocapnia (.10 ± .04 vs. .17 ± .06; P < .001) secondary to a decrease in AMPCaBV (1.3 ± .4 vs. 1.9 ± .5; P < .001) and a concomitant increase in AMPABP (13.8 ± 3.4 vs. 11.6 ± 1.7 mmHg; P < .001). During hypercapnia, there was no change in Ca compared with normocapnia. Ca was inversely correlated with the cerebrovascular resistance during hypo- (R2 = 0.86; P < .001), and hypercapnia (R2 = 0.61; P < .001). CONCLUSION: Using a new mathematical model, we have described a reduction of Ca during hypocapnia. Further studies are needed to determine whether Ca may be an independent predictor of outcome in pathological conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE Single gate transcranial Doppler spectrogram (sgTCD) has a high variability in the detection of microembolic signals (MES), Adding Power M-mode Doppler (PMD) information may improve MES detection. Our study's aim is to derive combined PMD/sgTCD microemboli criteria to overcome this limitation. METHODS Patients with symptomatic carotid disease were prospectively enrolled within 24 h of symptom onset underwent 1 hour TCD emboli monitoring. We reviewed disparity between PMD MES criteria and sgTCD MES criteria. We compared combined PMD/sgTCD criteria to sgTCD alone criteria by measuring the intraclass correlation coefficient (ICC). RESULTS Of 92 patients, 28 patients had evidence of MES on sgTCD or PMD. Total MES count was 269 based on sgTCD criteria, and 326 based on combined PMD/sgTCD criteria ( P= 0.005). Combined PMD/sgTCD criteria revealed 17 MESs (4.8%) based on sgTCD criteria to represent artifacts and 57 MESs (17.5%) not to be detected by sgTCD criteria. Overall ICC based on sgTCD criteria was 0.67 [95% confidence interval (CI): 0.58-0.74]; however, introducing combined PMD/sgTCD criteria resulted in a significant increase in the ICC, 0.91 (95% CI: 0.88-0.93). CONCLUSION Our combined PMD/sgTCD criteria for MES appeared to improve the yield of MES detection. Reliability in MES detection interpretation was improved when combined PMD/sgTCD criteria was applied. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE Current criteria for middle cerebral artery (MCA) stenosis by transcranial Doppler were mainly based on the flow velocity acceleration, ignoring other useful parameters. We tested the accuracy of new criteria using magnetic resonance angiography (MRA) as the confirmative method. METHODS A compositive score for each MCA was calculated according to following parameters: Velocity Scale (score 0-6 for peak systolic velocity <140 to ≥300 cm/second), Hemodynamic Scale (score 0-5 for diffuse or focal velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), and Spectrum Scale (score 0-2 for normal spectrum, turbulence, and musical murmurs). RESULTS The median scores in normal-mild, moderate, and severe groups on MRA differed significantly ( P < .001). The optimal cutoff score for <50% and ≥50% stenosis was 3 with the PPV of 72.3% (95% confidence interval [CI]: 65.3% to 78.5%) and negative predictive value (NPV) of 89.5% (95% CI: 85.9% to 92.3%), for moderate and severe stenosis was 6 with the PPV of 85.9% (95% CI: 76.7% to 92.0%) and NPV of 61.9% (95% CI: 50.6% to 72.1%). Both scores performed better than peak systolic or mean velocity. CONCLUSIONS This new method was feasible and reliable and showed some advantages over the velocity-only method. Further studies using digital subtraction angiography as the gold standard are needed to ameliorate the new criteria. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE The aim of this study was to investigate whether physiological factors, including body mass index (BMI), are associated with detection of right-to-left shunt (RLS) by contrast transcranial Doppler ultrasonography (c-TCD). METHODS After prospective c-TCD for stroke patients, we compared clinical backgrounds between patients with positive and negative results for RLS. After counting microembolic signals (MES), RLS were functionally graded as follows (grade 0 = 0 MES, grade I = 1-10 MES, grade II = 11-30 MES, grade III = 31-100 MES if countable, grade IV = over 100 MES or uncountable like a shower. RESULTS Subjects comprised 584 patients (203 men, 381 women) with a mean age of 67.9 ± 11.1 years. RLS was detected in 134 of 584 patients (23%). In univariate analysis, mean BMI was 22.1 in patients with RLS and 23.3 in those without RLS ( P= .004). Mean BMI in concordance with RLS grade gradually decreased (grade 0; 22.7, grade I; 20.8, grade II; 20.1, grade III; 19.6, P= .001). After performing the Valsalva maneuver, mean BMI in concordance with RLS grade linearly increased (grade I; 20.6, grade II; 23.2, grade III; 24.8, grade IV; 25.8, P < .001). CONCLUSION Although smaller body size may be associated with detection of RLS, a patient with significant RLS (grade III or IV) had larger body. [ABSTRACT FROM AUTHOR]