Generalized models for estimating cerebral lateralisation of young children using functional transcranial Doppler ultrasound.

Thompson et al., 2023 (Generalized models for quantifying laterality using functional transcranial Doppler ultrasound. Human Brain Mapping, 44(1), 35-48) introduced generalised model-based analysis methods for determining cerebral lateralisation from functional transcranial Doppler ultrasound (fTCD) data which substantially decreased the uncertainty of individual lateralisation estimates across several large adult samples. We aimed to assess the suitability of these methods for increasing precision in lateralisation estimates for child fTCD data. We applied these methods to adult fTCD data to establish the validity of two child-friendly language and visuospatial tasks. We also applied the methods to fTCD data from 4- to 7-year-old children. For both samples, the laterality estimates from the complex generalised additive model (GAM) approach correlated strongly with the traditional methods while also decreasing individual standard errors compared to the popular period-of-interest averaging method. We recommend future research using fTCD with young children consider using GAMs to reduce the noise in their LI estimates.

The characteristic and biomarker value of transcranial sonography in cerebellar ataxia.

OBJECTIVE: Transcranial sonography (TCS) is a noninvasive neuroimaging technique, visualizing deep brain structures and the ventricular system. Although widely employed in diagnosing various movement disorders, such as Parkinson's disease and dystonia, by detecting disease-specific abnormalities, the specific characteristics of the TCS in cerebellar ataxia remain inconclusive. We aimed to assess the potential value of TCS in patients with cerebellar ataxias for disease diagnosis and severity assessment. METHODS: TCS on patients with genetic and acquired cerebellar ataxia, including 94 with spinocerebellar ataxias (SCAs) containing 10 asymptomatic carriers, 95 with cerebellar subtype of multiple system atrophy (MSA-C), and 100 healthy controls (HC), was conducted. Assessments included third ventricle width, substantia nigra (SN) and lentiform nucleus (LN) echogenicity, along with comprehensive clinical evaluations and genetic testing. RESULTS: The study revealed significant TCS abnormalities in patients with cerebellar ataxia, such as enlarged third ventricle widths and elevated rates of hyperechogenic SN and LN. TCS showed high accuracy in distinguishing patients with SCA or MSA-C from HC, with an AUC of 0.870 and 0.931, respectively. TCS abnormalities aided in identifying asymptomatic SCA carriers, effectively differentiating them from HC, with an AUC of 0.725. Furthermore, third ventricle width was significantly correlated with SARA and ICARS scores in patients with SCA3 and SCOPA-AUT scores in patients with MSA-C. The SN area and SARA or ICARS scores in patients with SCA3 were also positively correlated. INTERPRETATION: Our findings illustrate remarkable TCS abnormalities in patients with cerebellar ataxia, serving as potential biomarkers for clinical diagnosis and progression assessment.

Noninvasive Intracranial Pressure Monitoring: Are We There Yet?

There is an urgent unmet need for a reliable noninvasive tool to detect elevations in intracranial pressure (ICP) above guideline-recommended thresholds for treatment. Gold standard invasive ICP monitoring is unavailable in many settings, including resource-limited environments, and in situations such as liver failure in which coagulopathy increases the risk of invasive monitoring. Although a large number of noninvasive techniques have been evaluated, this article reviews the potential clinical role, if any, of the techniques that have undergone the most extensive evaluation and are already in clinical use. Elevations in ICP transmitted through the subarachnoid space result in distension of the optic nerve sheath. The optic nerve sheath diameter (ONSD) can be measured with ultrasound, and an ONSD threshold can be used to detect elevated ICP. Although many studies suggest this technique accurately detects elevated ICP, there is concern for risk of bias and variations in ONSD thresholds across studies that preclude routine use of this technique in clinical practice. Multiple transcranial Doppler techniques have been used to assess ICP, but the best studied are the pulsatility index and the Czosnyka method to estimate cerebral perfusion pressure and ICP. Although there is inconsistency in the literature, recent prospective studies, including an international multicenter study, suggest the estimated ICP technique has a high negative predictive value (> 95%) but a poor positive predictive value (≤ 30%). Quantitative pupillometry is a sensitive and objective method to assess pupillary size and reactivity. Proprietary indices have been developed to quantify the pupillary light response. Limited data suggest these quantitative measurements may be useful for the early detection of ICP elevation. No current noninvasive technology can replace invasive ICP monitoring. Where ICP monitoring is unavailable, multimodal noninvasive assessment may be useful. Further innovation and research are required to develop a reliable, continuous technique of noninvasive ICP assessment.

To Accelerate the Process of Brain Death Determination in China Through the Strategy and Practice of Establishing Demonstration Hospitals.

BACKGROUND: Our objective was to explore whether a brain death determination (BDD) strategy with demonstration hospitals can accelerate the process of BDD in China. METHODS: We proposed the construction standards for the BDD quality control demonstration hospitals (BDDHs). The quality and quantity of BDD cases were then analyzed. RESULTS: A total of 107 BDDHs were established from 2013 to 2022 covering 29 provinces, autonomous regions, and municipalities under jurisdiction of the central government of the Chinese mainland (except Qinghai and Tibet). A total of 1,948 professional and technical personnel from these 107 BDDHs received training in BDD, 107 quality control personnel were trained in the quality control management of BDD, and 1,293 instruments for electroencephalography, short-latency somatosensory evoked potential recordings, and transcranial Doppler imaging were provided for BDD. A total of 6,735 BDD cases were submitted to the quality control center. Among the nine quality control indicators for BDD in these cases, the implementation rate, completion rate, and coincidence rate of apnea testing increased the most, reaching 99%. CONCLUSIONS: The strategy of constructing BDDHs to promote BDD is feasible and reliable. Ensuring quality and quantity is a fundamental element for the rapid and orderly popularization of BDD in China.

Clinical applications of point-of-care ultrasound in brain injury: a narrative review.

The use of point-of-care ultrasound has increased considerably over the last two decades. It has become a readily available, non-invasive bed-side modality for the rapid diagnosis and management of patients in various settings. Point-of-care ultrasound for assessing the heart, lung, abdomen, airway and vascular systems is now well established. Transcranial Doppler ultrasound for assessing cerebral blood flow has been in use for many years. In recent years, brain ultrasonography has been shown to be a powerful tool in the rapid bed-side assessment of cerebral haemodynamics and structural pathology. Brain ultrasound has been shown to be useful in both the emergency department and neurocritical care setting for the non-invasive assessment of raised intracranial pressure, cerebral autoregulation and diagnosis of intracranial haematoma and other space-occupying lesions. Point-of-care ultrasound is an important alternative technique to routine imaging and invasive monitoring techniques, and results are comparable. Competence is easily attainable without formal radiology training. With technological advancement, applications for the use of brain ultrasound continue to grow. This review discusses the clinical use of point-of-care ultrasound in the diagnosis and management of brain injury.

Serial neurosonography in fetuses with congenital heart defects shows mild delays in cortical development.

INTRODUCTION: Neurodevelopmental delay is more common in children born with congenital heart defects (CHD), even with optimal perinatal and peri-operative care. It is hypothesized that fetuses with CHD are prone to neurological impairment in utero due to their cardiac defect, possibly leading to delayed cortical development. METHODS: Cerebral cortical maturation was assessed with advanced neurosonographic examinations every 4 weeks in fetuses with CHD and compared to control fetuses. Five different primary fissures and four areas were scored (ranging 0-5) by blinded examiners using a cortical maturation scheme. RESULTS: Cortical staging was assessed in 574 ultrasound examinations in 85 CHD fetuses and 61 controls. Small differences in grading were seen in Sylvian and cingulate fissures. (Sylvian fissure: -0.12 grade, 95% CI (-0.23; -0.01) p = 0.05, cingulate fissure: -0.24 grade, 95% CI (-0.38; -0.10) p = <0.001. Other cortical areas showed normal maturation as compared to control fetuses. CONCLUSION: Small differences were seen in three of the nine analyzed cortical areas in CHD fetuses, in contrast to previous reports on progressive third-trimester delay. The clinical implications of the small differences however, remain unknown.

Early Use of Transcranial Doppler Ultrasonography to Stratify Neonatal Encephalopathy.

BACKGROUND: The dynamic nature of neonatal hypoxic-ischemic encephalopathy (HIE) after birth necessitates reliable biomarkers to identify infants with evolving brain injury. This prospective cohort aims to use serial Doppler ultrasonography (US) to measure cerebral blood flow velocity and resistance index (RI) to help detect the time and evolution of the clinical encephalopathy. METHODS: A total of 60 neonates were enrolled all ≥36 weeks' gestation with perinatal acidemia, defined as a blood gas pH ≤ 7.0 or base deficit ≥16 mmol/L and encephalopathy including a matched control group without encephalopathy. Each neonate received one to three serial Doppler recordings starting at six to 24 hours of life. Mean RI ≤ 0.55 was considered abnormal. RESULTS: Mean RIs obtained shortly after birth were significantly lower with increasing severity of encephalopathy. On the first Doppler recordings, abnormal mean RIs were seen in 11 of 18 (61%) neonates with mild, 13 of 17 (76%) with moderate, and two of two (100%) with severe HIE. Of the neonates with mild HIE and abnormal mean RIs, congruity abnormal amplitude electroencephalography (45%), brain magnetic resonance imaging (45%), and abnormal head ultrasound (44%) are here reported. CONCLUSIONS: Doppler measurements can provide bedside adjunct biomarkers indicating the time and severity of neonatal HIE.

Does depth of squat-stand maneuver affect estimates of dynamic cerebral autoregulation?

Repeated squat-stand maneuvers (SSM) are an effective way of measuring dynamic cerebral autoregulation (dCA), but the depth of SSM required to improve dCA estimations has never been studied. We compared beat-to-beat cerebral hemodynamic parameters between maximal depth SSM (SSMD ) and a shallower alternative (SSMS ) in two age groups (younger [20-34 years] vs. older [50-71 years]) at a frequency of 0.05 Hz. Cerebral blood flow velocity, continuous blood pressure (BP) and end-tidal CO2 (EtCO2 ) were measured using transcranial Doppler ultrasound, the Finometer device, and capnography, respectively. Coherence (at 0.05 Hz) was significantly higher in both SSM recordings compared to spontaneous BP oscillations at baseline standing (BS ). Median (IQR) autoregulation index (ARI) was reduced during SSMD (4.46 [4.03-5.22], p < .01) compared to SSMS (5.96 [5.40-6.69]) and BS (6.03 [5.20-6.49], p < .01) with similar relative differences also observed for phase (at 0.05 Hz). End-tidal CO2 was increased in SSMD (38.3 ± 3.7 mmHg, p < .01) compared to both SSMS (36.6 ± 3.6 mmHg) and BS (35.5 ± 3.2 mmHg). The older group demonstrated significantly lower ARI and phase estimates during SSM and found SSMS more effortful than SSMD . In conclusion, both SSMD and SSMS are effective at estimating dCA, and dCA appears to be less efficient during maximal depth SSM compared to baseline rest or a shallower alternative.

Cranial ultrasound evaluation in term neonates.

BACKGROUND: Term neonates (TN) are not routinely submitted to cranial ultrasound scan (CUS), since they are not considered at high risk for developing cerebral lesions. AIMS: To investigate the prevalence of cerebral abnormal findings in term neonates (TN), to identify the associated clinical features and to better target neonatal CUS investigations. STUDY DESIGN: Prospective observational study. SUBJECTS: A total number of 1805 healthy TN underwent CUS. 1181 neonates had clinical features supposed to increase the risk for cerebral abnormal findings (study cohort), 624 were controls. OUTCOME MEASURES: Prevalence of minimal, minor, and major cerebral abnormal findings was analyzed in six different categories of low-risk TN and compared to controls. RESULTS: Variations from normality at the neonatal CUS were observed in 402 TN (22.27%). In half of the cases the ultrasound findings were minimal abnormal findings, while minor abnormal findings were found in 179 TN (9.92%). About 1% of the studied neonates showed major cerebral abnormal findings potentially compromising neurodevelopmental outcome. The prevalence of the observed abnormal findings varied significantly in the different low-risk categories. CONCLUSIONS: The clinical features significantly increasing the risk for cerebral anomalies in healthy TN were microcrania, macrocrania, mild neurologic signs, and the detection of mild variations from normal cerebral aspect at the antenatal ultrasound evaluation.

Comparative Analysis of Simultaneous Transcranial Doppler and Perfusion Computed Tomography for Cerebral Perfusion Evaluation in Patients with Traumatic Brain Injury.

The aim was to investigate the feasibility of simultaneous comparison of cerebral circulation in major vessels and microvasculature in patients suffering traumatic brain injury (TBI) with or without intracranial hematomas (IH). METHODS: 170 patients were divided into two groups: Group 1 - diffuse TBI (75 patients); and Group 2 - TBI with IH (95 patients: 18 epidural, 65 subdural and 12 multiple). Perfusion computed tomography (PCT) for assessment of volumetric cerebral blood flow (CBF) was done 2-15 days after admission to hospital. Simultaneous assessment of cerebral blood flow velocity (CBFV) in both middle cerebral arteries was done by transcranial Doppler. RESULTS: In patients with diffuse TBI, CBF had statistically valid correlations with CBFV (r = 0.28, p = 0.0149 on the left side; r = 0.382, p = 0.00075 on the right side). In patients with TBI and IH, the analysis did not reveal any reliable correlations between the CBFV and CBF velocity in the temporal lobes, either on the side of the removed IH or on the opposite side. CONCLUSION: The greatest linear correlation was noted in patients with diffuse TBI without the development of a coarse shift of the midline structures and dislocation syndrome. This correlation decreases with the increase in injury severity and development of secondary complications in the acute period, which probably reflects impairment of the coupling of oxygen consumption by brain tissue and cerebral microcirculation.

Transtemporal Ultrasound (US) Assessment of Third Ventricle Diameter (TVD): Comparison of US and MRI TVD in Pediatric Patients.

INTRODUCTION: In a retrospective magnetic resonance imaging (MRI)-based study, we showed that changes of the third ventricle diameter (TVD) are a reliable mirror of changes of the entire ventricular system. The third ventricle is easily accessible in more than 90% of children and adults using ultrasound (US) via the transtemporal bone-window; thus it can be assessed quickly and free of radiation. In order to use transtemporal US determination of TVD instead of MRI/CT in clinical practice, it is important to know if there is a correlation and bias between both methods, which is addressed in this study. MATERIALS AND METHOD: This prospective study investigates 122 children (newborn-18 years). Diagnoses encompassed hydrocephalus (50%), tumors (14.8%), and other intracranial pathologies (35.2%). US-based TVD was measured via the transtemporal bone-window using a phased array 1 to 4MHz transducer. Results were compared with TVD measured on simultaneously acquired axial T1-weighted axial MRI or computed tomography (CT) scans. RESULTS: Overall mean values for TVD were 6.56 ± 5.84 and 6.47 ± 5.64 mm for US and MRI, respectively. There was an outstanding correlation between TVD measured by MRI and US (r = 0.991, p < 0.01). Bland-Altman analysis showed a mean bias of 0.096 mm with limits of agreement of -0.99 and 1.18 mm. CONCLUSION: US- and MRI-based TVD measurements correlate excellently and measure almost identical TVD values. US-based TVD is in mean ∼0.096 mm larger than MRI-based TVD due to a more angulated measurement plane. US is equal to the gold-standard MRI, a fact, opening new avenues for US-based TVD as a first-line assessment tool of ventricular width.

Validation of non-invasive cerebrovascular pressure reactivity and pulse amplitude reactivity indices in traumatic brain injury.

BACKGROUND: Two transcranial Doppler (TCD) estimators of cerebral arterial blood volume (CaBV) coexist: continuous outflow of arterial blood outside the cranium through a low-pulsatile venous system (continuous flow forward, CFF) and pulsatile outflow through regulating arterioles (pulsatile flow forward, PFF). We calculated non-invasive equivalents of the pressure reactivity index (PRx) and the pulse amplitude index PAx with slow waves of mean CaBV and its pulse amplitude. METHODS: About 273 individual TBI patients were retrospectively reviewed. PRx is the correlation coefficient between 30 samples of 10-second averages of ICP and mean ABP. PAx is the correlation coefficient between 30 samples of 10-second averages of the amplitude of ICP (AMP, derived from Fourier analysis of the raw full waveform ICP tracing) and mean ABP. nPRx is calculated with CaBV instead of ICP and nPAx with the pulse amplitude of CaBV instead of AMP (calculated using both the CFF and PFF models). All reactivity indices were additionally compared with Glasgow Outcome Score (GOS) to verify potential outcome-predictive strength. RESULTS: When correlated, slow waves of ICP demonstrated good coherence between slow waves in CaBV (>0.75); slow waves of AMP showed good coherence with slow waves of the pulse amplitude of CaBV (>0.67) in both the CFF and PFF models. nPRx was moderately correlated with PRx (R = 0.42 for CFF and R = 0.38 for PFF; p < 0.0001). nPAx correlated with PAx with slightly better strength (R = 0.56 for CFF and R = 0.41 for PFF; p < 0.0001). nPAx_CFF showed the strongest association with outcomes. CONCLUSIONS: Non-invasive estimators (nPRx and nPAx) are associated with their invasive counterparts and can provide meaningful associations with outcome after TBI. The CFF model is slightly superior to the PFF model.

Acoustic biomolecules enhance hemodynamic functional ultrasound imaging of neural activity.

Hemodynamic functional ultrasound imaging (fUS) of neural activity provides a unique combination of spatial coverage, spatiotemporal resolution and compatibility with freely moving animals. However, deep and transcranial monitoring of brain activity and the imaging of dynamics in slow-flowing blood vessels remains challenging. To enhance fUS capabilities, we introduce biomolecular hemodynamic enhancers based on gas vesicles (GVs), genetically encodable ultrasound contrast agents derived from buoyant photosynthetic microorganisms. We show that intravenously infused GVs enhance ultrafast Doppler ultrasound contrast and visually-evoked hemodynamic contrast in transcranial fUS of the mouse brain. This hemodynamic contrast enhancement is smoother than that provided by conventional microbubbles, allowing GVs to more reliably amplify neuroimaging signals.

Brain Ultrasonography Consensus on Skill Recommendations and Competence Levels Within the Critical Care Setting.

BACKGROUND: To report a consensus on the different competency levels for the elaboration of skill recommendations in performing brain ultrasonography within the neurocritical care setting. METHODS: Four brain ultrasound experts, supported by a methodologist, performed a preselection of indicators and skills based on the current literature and clinical expertise. An international panel of experts was recruited and subjected to web-based questionnaires according to a Delphi method presented in three separate rounds. A pre-defined threshold of agreement was established on expert subjective opinions, > 84% of votes was set to support a strong recommendation and > 68% for a weak recommendation. Below these thresholds, no recommendation reached. RESULTS: We defined four different skill levels (basic, basic-plus, pre-advanced, advanced). Twenty-five experts participated to the full process. After four rounds of questions, two items received a strong recommendation in the basic skill category, three in the advanced, twelve in the basic-plus, and seven in the pre-advanced. Two items in the pre-advanced category received a weak recommendation and three could not be collocated and were excluded from the list. CONCLUSIONS: Results from this consensus permitted stratification of the different ultrasound examination skills in four levels with progressively increasing competences. This consensus can be useful as a guide for beginners in brain ultrasonography and for the development of specific training programs within this field.

Increased substantia nigra echogenicity correlated with visual hallucinations in Parkinson's disease: a Chinese population-based study.

As a noninvasive technique, transcranial sonography (TCS) of substantia nigra (SN) has gradually showed its effectiveness not only in diagnosis but also in understanding clinical features of Parkinson's Disease (PD). This study aimed to further evaluate TCS for clinical diagnosis of PD, and to explore the association between sonographic manifestations and visual hallucinations (VH). A total of 226 subjects including 141 PD patients and 85 controls were recruited. All participants received TCS. A series of rating scales to evaluate motor and non-motor symptoms were performed in PD patients. Results showed that 172 subjects were successfully assessed by TCS. The area of SN was greater in PD patients than that in controls (P < 0.001). As receiver-operating characteristic (ROC) curve analysis showed, the best cutoff value for the larger SN echogenicity size was 23.5 mm2 (sensitivity 70.3%, specificity 77.0%). Patients with VH had larger SN area (P = 0.019), as well as higher Non-Motor Symptoms Scale (NMSS) scores (P = 0.018). Moreover, binary logistic regression analysis indicated that SN hyperechogenicity (odds ratio = 4.227, P = 0.012) and NMSS scores (odds ratio = 0.027, P = 0.042) could be the independent predictors for VH. In conclusion, TCS can be used as an auxiliary diagnostic tool for Parkinson's disease. Increased SN echogenicity is correlated with VH in Parkinson's disease, possibly because the brain stem is involved in the mechanism in the onset of VH. Further studies are needed to confirm these findings.

Latin American Consensus Statement for the Use of Contrast-Enhanced Transcranial Ultrasound as a Diagnostic Test for Detection of Right-to-Left Shunt.

BACKGROUND: The role of patent foramen ovale is a field of debate and current publications have increasing controversies about the patients' management in young undetermined stroke. Work up with echocardiography and transcranial Doppler (TCD) can aid the decision with better anatomical and functional characterization of right-to-left shunt (RLS). Medical and interventional strategy may benefit from this information. SUMMARY: a group of experts from the Latin American participants of the Neurosonology Research Group (NSRG) of World Federation of Neurology created a task force to review literature and describe the better methodology of contrast TCD (c-TCD). All signatories of the present consensus statement have published at least one study on TCD as an author or co-author in an indexed journal. Two meetings were held while the consensus statement was being drafted, during which controversial issues were discussed and voted on by the statement signatories. The statement paper was reviewed and approved by the Executive Committee of the NSRG of the World Federation of Neurology. The main objective of this consensus statement is to establish a standardization of the c-TCD technique and its interpretation, in order to improve the informative quality of the method, resulting in expanding the application of TCD in the clinical setting. These recommendations optimize the comparison of different diagnostic methods and encourage the use of c-TCD for RLS screening and complementary diagnosis in multicenter studies.

Transcranial sonography in atypical parkinsonism: How reliable is it in real clinical practice? A multicentre comprehensive study.

INTRODUCTION: Substantia nigra hyperechogenicity (SN+) in transcranial sonography (TCS) is frequent in Parkinson's disease (PD), while lenticular nucleus hyperechogenicity (LN+) and 3rd ventricle enlargement (3V+) are typical of Atypical Parkinsonisms (AP). However, there are no studies assessing the diagnostic yield of all TCS biomarkers in the three AP (progressive supranuclear palsy, PSP, multiple system atrophy, MSA, corticobasal degeneration, CBD). Previous references lack homogeneous criteria and data are incomprehensive. METHODS: Analysis of TCS performed in routine clinical practice in AP and PD patients from two tertiary hospitals. Expert recommendations were strictly followed. Previous literature was critically analysed. RESULTS: 155 AP (98 PSP, 40 MSA, 14 CBD), 254 PD, 145 control subjects were included. We confirmed good sensitivity for SN+ in PD (80%), but specificity was lower than reported (61%). LN+ and 3V + had moderate sensitivity for AP and PSP diagnosis respectively (65%, 63%), but specificity was higher than reported (87%, 91%). We confirmed high specificity and positive predictive value of the combination SN/LN (98%, 93% AP; 83%, 86% PD). The combinations of two or three echofeatures, previously unreported, showed high specificity but lower sensitivity (SN/3V: 75% sensitivity, 87% specificity PD; 42% sensitivity, 98% specificity PSP) (SN + LN+: 79% sensitivity, 86% specificity CBD) (SN/3V/LN: 67% sensitivity, 89% specificity PD; 29% sensitivity, 99% specificity PSP; 41% sensitivity, 95% specificity MSA; 57% sensitivity 91% specificity CBD). CONCLUSIONS: We present a large comprehensive study of TCS, confirming its usefulness and certain limitations in AP diagnosis. Adherence to consensus criteria is critical to implement TCS for clinical and research purposes.

Validación de un laboratorio básico de neurosonología para la detección de estenosis carotídea cervical / Validation of a basic neurosonology laboratory for detecting cervical carotid artery stenosis

Introducción: La detección de estenosis arterial cervical e intracraneal es fundamental en el estudio del ictus isquémico, al ser el origen aterotrombótico el más prevalente en nuestro entorno. La ultrasonografía se ha convertido, por su accesibilidad y fiabilidad, en la técnica de elección para la primera aproximación al diagnóstico de esta patología, y debe ser validada en cada laboratorio en particular. El objetivo del presente trabajo es validar la técnica Doppler practicada en nuestro laboratorio para la detección de estenosis carotídea crítica. Pacientes y métodos: Se diseñó un estudio descriptivo observacional de evaluación de pruebas diagnósticas. Se compararon los resultados obtenidos sobre pacientes con diagnóstico de ictus mediante la técnica integrada Doppler carotídeo y transcraneal realizada por neurología, con los proporcionados por la técnica dúplex carotídeo, dependiente del servicio de radiología. El gold standard fue el resultado obtenido por una técnica arteriográfica (angio-RM, angio-TC o arteriografía convencional). Resultados: N = 228 pacientes. En la detección de estenosis carotídea > 70%, el Doppler cervical y transcraneal tenía una sensibilidad y especificidad del 96 y el 100%, respectivamente, frente al 87 y el 94% obtenidos por el dúplex exclusivamente cervical. Para las estenosis intracraneales detectadas mediante Doppler transcraneal, esos parámetros fueron del 78 y el 98%, respectivamente. Conclusiones: El estudio Doppler realizado en el laboratorio de neurosonología quedó validado como herramienta diagnóstica útil para la detección de estenosis carotídea cervical, siendo superior al dúplex cervical aislado, pese a la ausencia de modo B. Demostró, además, un valor adicional como técnica de detección de estenosis arterial intracraneal

Introduction: Most of the cases of ischaemic stroke in our setting are of atherothrombotic origin. Detecting intracranial and cervical carotid artery stenosis in patients with ischaemic stroke is therefore essential. Ultrasonography has become the tool of choice for diagnosing carotid artery stenosis because it is both readily accessibility and reliable. However, use of this technique must be validated in each laboratory. The purpose of this study is to validate Doppler ultrasound in our laboratory as a means of detecting severe carotid artery stenosis. Patients and methods: We conducted an observational descriptive study to evaluate diagnostic tests. The results from transcranial and cervical carotid Doppler ultrasound scans conducted by neurologists were compared to those from carotid duplex scans performed by radiologists in patients diagnosed with stroke. Arteriography was considered the gold standard (MR angiography, CT angiography, or conventional arteriography). Results: Our sample included 228 patients. Transcranial and cervical carotid Doppler ultrasound showed a sensitivity of 95% and specificity of 100% for detection of carotid artery stenosis > 70%, whereas carotid duplex displayed a sensitivity of 87% and a specificity of 94%. Transcranial carotid Doppler ultrasound achieved a sensitivity of 78% and a specificity of 98% for detection of intracranial stenosis. Conclusions: Doppler ultrasound in our neurosonology laboratory was found to be a useful diagnostic tool for detecting cervical carotid artery stenosis and demonstrated superiority to carotid duplex despite the lack of B-mode. Furthermore, this technique was found to be useful for detecting intracranial stenosis

Systematic review with network meta-analysis: Diagnostic values of ultrasonography, computed tomography, and magnetic resonance imaging in patients with ischemic stroke.

BACKGROUND AND OBJECTIVE: Ischemic stroke is a foremost cause for disability and death worldwide. This study is conducted in order to compare the diagnostic values between transcranial Doppler ultrasound (ultrasonography), computed tomography (CT), and magnetic resonance imaging (MRI) in patients suffering from ischemic stroke by performing a network meta-analysis. METHODS: We made use of Cochrane Library, PubMed, and Embase in order to obtain literature and papers. The combination analysis of both direct and indirect evidence in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy was conducted so as to assess the odds ratios (ORs) and surface under the cumulative ranking curve (SUCRA) values of the seven different imaging methods. These imaging techniques include ultrasonography, computed tomography (traditional CT, computed tomography angiography [CTA], computed tomography perfusion [CTP]), and MRI (traditional MRI, diffusion-weighted imaging [DWI], magnetic resonance angiography), in order to properly diagnose ischemic stroke patients. RESULTS: Thirteen eligible diagnostic trials were enrolled into this network meta-analysis. The results of the traditional meta-analysis showed that among CT methods, CTP showed higher sensitivity, NPV, and accuracy; among MRI methods, DWI had relatively higher sensitivity, NPV, and accuracy. The results of network meta-analysis showed that DWI had relatively higher sensitivity, NPV, and accuracy when compared with traditional CT, CTA, magnetic resonance angiography and traditional MRI. CTP showed higher SUCRA among CT methods while DWI showed higher SUCRA among MRI methods. A cluster analysis revealed that DWI had the highest diagnostic value in terms of sensitivity, PPV, NPV, and accuracy amongst the aforementioned seven imaging techniques. CONCLUSION: This network meta-analysis provides supporting evidence to the idea that DWI has a higher diagnostic value regarding ischemic stroke among MRI methods, and CTP has a poor diagnostic value among CT methods, which provide therapeutic considerations for Ischemic stroke intervention.

Can interhemispheric desynchronization of cerebral blood flow anticipate upcoming vasospasm in aneurysmal subarachnoid haemorrhage patients?

BACKGROUND: Asymmetry of cerebral autoregulation (CA) was demonstrated in patients after aneurysmal subarachnoid haemorrhage (aSAH). A classical method for CA assessment requires simultaneous measurement of both arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). In this study, we have proposed a cerebral blood flow asymmetry index based only on CBFV and analysed its association with the occurrence of vasospasm after aSAH. NEW METHOD: The phase shifts (PS) between slow oscillations in left and right CBFV (side-to-side PS) and between ABP and CBFV (CBFV-ABP PS) were estimated using multichannel matching pursuit (MMP) and cross-spectral analysis. RESULTS: We retrospectively analysed data collected from 45 aSAH patients (26 with vasospasm). Data were analysed up to 7th day after aSAH unless the vasospasm was detected earlier. A progressive asymmetry, manifested by a gradual increase in side-to-side PS on consecutive days after aSAH, was observed in patients who developed vasospasm (Radj2 = 0.14, p = 0.009). In these patients, early side-to-side PS was more positive than in patients without vasospasm (2.8° ± 5.6° vs -1.7° ± 5.7°, p = 0.011). No such a difference was found in CBFV-ABP PS. Patients with positive side-to-side PS were more likely to develop vasospasm than patients with negative side-to-side PS (21/7 vs 5/12, p = 0.0047). COMPARISON WITH EXISTING METHOD: MMP, in contrast to the spectral approach, accounts for non-stationarity of analysed signals. MMP applied to the PS estimation reflects the cerebral blood flow asymmetry in aSAH better than the spectral analysis. CONCLUSIONS: Changes in side-to-side PS might be helpful to identify patients who are at risk of vasospasm.