Factors affecting transtemporal window quality in transcranial sonography

Continuous transcranial ultrasound in large vessel stroke: Image guidance for high-intensity focused sonothrombolysis

BACKGROUND AND PURPOSE

Sonothrombolysis is a potential adjunctive therapy for large vessel occlusion (LVO) stroke. Bedside ultrasound image-guided high-intensity focused ultrasound (HIFU) therapy could deliver higher energy therapeutic ultrasound to the thrombus with higher precision than what was previously accomplished in human trials. The aim is to test the feasibility of diagnostic transcranial contrast-enhanced ultrasound (CEUS) to image the occlusion site and continuously maintain the guidance image on-target for a sufficient exposure time for HIFU to be effective during LVO stroke evaluation and treatment.

METHODS

This prospective, single center, observational cohort study included adult patients, presenting within 6 hours of stroke symptom onset, with LVO identified on computed tomography angiography (CTA). A hand-held CEUS imaging study was initiated following CTA and lasted up to 30 minutes. The primary outcome is the proportion of patients where a guidance CEUS image of the occlusion was achieved.

RESULTS

A CEUS image of the occluded artery was obtained in 32/35 of the included patients. The median total imaging time was 23 minutes (interquartile range 15-30). Patients undergoing thrombectomy had a lower total imaging time (17 vs. 29.5 minutes, p = .002). When imaging was successful, on-target image was maintained for only 58% (standard deviation 23.8%) of total imaging time. No complications related to CEUS were observed.

CONCLUSIONS

This feasibility study explored the use of diagnostic transcranial CEUS for continuous imaging of occlusion sites in LVO strokes. Challenges in maintaining target image during HIFU were identified, highlighting the need for technical advances for clinical application.

Robotic Assisted Transcranial Doppler Monitoring in Acute Neurovascular Care: A Feasibility and Safety Study

BACKGROUND

Transcranial color Doppler (TCD) is currently the only noninvasive bedside tool capable of providing real-time information on cerebral hemodynamics. However, being operator dependent, TCD monitoring is not feasible in many institutions. Robotic assisted TCD (ra-TCD) was recently developed to overcome these constraints. The aim of this study was to evaluate the safety and feasibility of cerebral monitoring with a novel ra-TCD in acute neurovascular care.

METHODS

This is a two-center prospective study conducted between August 2021 and February 2022 at Padua University Hospital (Padua, Italy) and Kepler University Hospital (Linz, Austria). Adult patients with conditions impacting cerebral hemodynamics or patients undergoing invasive procedures affecting cerebral hemodynamics were recruited for prolonged monitoring (> 30 min) of the middle cerebral artery with a novel ra-TCD (NovaGuide Intelligent Ultrasound, NeuraSignal, Los Angeles, CA). Manual TCD was also performed for comparison by an experienced operator. Feasibility and safety rates were recorded.

RESULTS

A total of 92 patients (age: mean 68.5 years, range 36-91; sex: male 57 [62%]) were enrolled in the two centers: 54 in Padua, 38 in Linz. The examination was feasible in the majority of patients (85.9%); the head cradle design and its radiopacity hindered its use during carotid endarterectomy and mechanical thrombectomy. Regarding safety, only one patient (1.1%) reported a minor local edema due to prolonged probe pressure. Velocity values were similar between ra-TCD and manual TCD.

CONCLUSIONS

This novel ra-TCD showed an excellent safety and feasibility and proved to be as reliable as manual TCD in detecting blood flow velocities. These findings support its wider use for cerebral hemodynamics monitoring in acute neurovascular care. However, further technical improvements are needed to expand the range of applicable settings.

Development of a prediction model for facilitating the clinical application of transcranial color-coded duplex ultrasonography

BACKGROUND

Transcranial color-coded duplex ultrasonography (TCCD) is an important diagnostic tool in the investigation of cerebrovascular diseases. TCCD is often hampered by the temporal window that ultrasound cannot penetrate. Rapidly determine whether ultrasound can penetrate the temporal window in order to determine whether to use other acoustic windows to complete the examination process. In this study, Skull thickness can be measured simultaneously during TCCD examination, which makes it possible to use skull thickness to rapidly determine whether the temporal window is penetrated by ultrasound.

METHODS

This retrospective study included 301 patients with clinical symptoms of cerebrovascular diseases. These 301 patients were divided into an impenetrable temporal window (ITW) group and a penetrable temporal window group according to the results of the TCCD examination.

RESULTS

The area under the receiver operating characteristic (ROC) curve (AUC) for skull thickness was 0.887 (cutoff value 1.045 cm). Following multivariate logistic regression, sex, age, and skull thickness were used to develop a nomogram. The AUC for the nomogram was 0.923 (cutoff value 0.407).

CONCLUSIONS

The skull thickness at the temporal window was measured by ultrasound, which was convenient and accurate. The probability of ITW in females was higher than that in males, and it increased with age. In this study, a prediction model incorporating sex, age and skull thickness could predict ITW probability well. If the patient's temporal window was rapidly predicted as an ITW, other acoustic window examinations were used to complete the TCCD examination process to optimize the TCCD examination process of cerebrovascular diseases and facilitate the popularization of TCCD in clinical application.

Differentiating progressive supranuclear palsy from other movement disorders using transcranial sonography: a systematic review and meta-analysis

Progressive supranuclear palsy (PSP) is an atypical parkinsonism that presents with different phenotypes. There are still no validated diagnostic biomarkers for early diagnosis of PSP. Transcranial sonography (TCS) is a promising tool in the differential diagnosis of parkinsonian disorders; however, there are no systematic investigations about the application of TCS in PSP patients. Therefore, we performed a systematic review and meta-analysis to discuss the role of TCS in diagnosing PSP by systematically searching PubMed, Cochrane Library, Chinese National Knowledge Infrastructure and Wan Fang databases. Of 66 obtained records, 16 articles, including 366 patients with PSP, were included. Our results showed the estimated random-effects pooled prevalence of substantia nigra hyperechogenicity in patients with PSP was 22% (95% CI 12-32%), lenticular nucleus hyperechogenicity was 70% (95% CI 52-82%), and enlarged third ventricle was 71% (95% CI 55-85%). Additionally, a normal echogenicity substantia nigra in TCS showed 70% sensitivity (95% CI 56-81%) and 86% specificity (95% CI 75-86%) to differentiate PSP from Parkinson's disease. In conclusion, TCS is an important supplementary biomarker for diagnosing PSP. At the same time, the diagnostic value of TCS in discriminating PSP from other atypical parkinsonism and between different PSP phenotypes needs further exploration.

Transcranial sonography in neurodegeneration with brain iron accumulation disorders

BACKGROUND

Transcranial Sonography is a non-invasive technique that has been used as a diagnostic tool for a variety of neurodegenerative disorders. However, the utility and potential application of this technique in NBIA disorders is scarce and inconclusive.

METHODS

In this cross-sectional retrospective case-control study, the echogenicity of Substantia Nigra (SN), Lentiform Nucleus (LN), and Diameter of the Third Ventricle (DTV) were assessed by TCS in genetically confirmed NBIA patients referring to the movement disorder clinic. The normal echogenicity area of SN was defined based on the 90th percentile of an age-and-gender-matched control group. NBIA patients underwent neurologic examination at each visit, but their brain magnetic resonance imaging and demographics were extracted from electronic records.

RESULTS

Thirty-five NBIA patients of four subtypes with a mean disease duration of 10.54 years and 35 controls were enrolled. The normally defined SN echogenicity in controls was 0.23 cm2. DTV and SN echogenicity areas were significantly higher in patients compared to the controls (P = 0.002 and < 0.001, respectively). Around 85% and 63% of the patients showed LN and SN hyperechogenicity at least on one side, respectively. Disease duration was positively correlated with DTV (r = 0.422, p = 0.015). Cases with Pantothenate Kinase Associated Neurodegeneration (n = 23) also had significantly higher DTV and SN echogenicity area compared to the controls.

CONCLUSION

Despite most NBIA patients displayed increased DVT and higher SN and LN hyperechogenicity than healthy controls, the discriminatory role of TCS on different NBIA subtypes remains to be determined.

Brain injury mobile diagnostic system: Applications in civilian medical service and on the battlefield-General concept and medical aspects

To present the concept of a portable ultrasound tomography device for diagnosing traumatic and vascular brain lesions. The device consisting of multiple transcranial ultrasound probes placed on the surface of the head, specifically but not exclusively in natural acoustic windows. An integral part of the mobile diagnostic system (MDS) is a decision support system based on artificial intelligence algorithms utilizing information from: head images, laboratory data, and assessment of the patient's clinical condition. The MDS can significantly reduce the time from stroke onset to rtPA therapy in civilian medical services and support therapeutic and evacuation strategies in instances of brain and skull trauma on the battlefield.

Quantitative regional cerebral blood flow measurement using near-infrared spectroscopy and indocyanine green in patients undergoing superficial temporal to middle cerebral artery bypass for moyamoya disease: a novel method using a frequency filter

Measuring regional cerebral blood flow (rCBF) after revascularization for moyamoya disease, as a type of ischemic cerebrovascular disease, is crucial. This study aims to validate our novel technology that combines near-infrared spectroscopy (NIRS) with a frequency filter to extract the arterial component. We measured rCBF before and after revascularization for moyamoya disease and at the end of the surgery using NIRO-200NX (Hamamatsu Photonics, Japan) and indocyanine green (ICG). rCBF was calculated using Fick's principle, change in arterial ICG concentrations, and maximum arterial ICG concentration. rCBF measured with NIRS (rCBF_N) was compared with pre- and postoperative rCBF measured with SPECT (rCBF_S). Thirty-four procedures were analyzed. rCBF_N increased from baseline to end of the surgery (mean difference (MD), 2.99 ml/min/100 g; 95% confidence interval (CI), 0.40-5.57 ml/min/100 g on the diseased side; MD, 4.94 ml/min/100 g; 95% CI, 2.35-7.52 ml/min/100 g on the non-diseased side). Similar trends were observed for rCBF_S (MD, 3.98 ml/min/100 g; 95% CI, 2.30-5.67 ml/min/100 g on the diseased side; MD, 2.77 ml/min/100 g; 95% CI, 1.09-4.45 ml/min/100 g on the non-diseased side). Intraclass correlations 3 (ICC3s) between rCBF_N and rCBF_S were weak on the diseased side (ICC3, 0.25; 95% CI, -0.03-0.5; p = 0.07) and the non-diseased side (ICC3, 0.24; 95% CI, -0.05-0.5; p = 0.08). rCBF measurements based on this novel method were weakly correlated with rCBF measurements with SPECT.