Robot-Assisted Transcranial Doppler Versus Transthoracic Echocardiography for Right to Left Shunt Detection.

BACKGROUND: Right to left shunt (RLS), including patent foramen ovale, is a recognized risk factor for stroke. RLS/patent foramen ovale diagnosis is made by transthoracic echocardiography (TTE), which is insensitive, transesophageal echocardiography, which is invasive, and transcranial Doppler (TCD), which is noninvasive and accurate but scarce. METHODS: We conducted a prospective, single-arm device clinical trial of robot-assisted TCD (raTCD) versus TTE for RLS diagnosis at 6 clinical sites in patients who presented with an event suspicious for embolic cerebrovascular ischemia from October 6, 2020 to October 20, 2021. raTCD was performed with standard TCD bubble study technique. TTE bubble study was performed per local standards. The primary outcome was rate of RLS detection by raTCD versus TTE. RESULTS: A total of 154 patients were enrolled, 129 evaluable (intent to scan) and 121 subjects had complete data per protocol. In the intent to scan cohort, mean age was 60±15 years, 47% were women, and all qualifying events were diagnosed as ischemic stroke or transient ischemic attack. raTCD was positive for RLS in 82 subjects (64%) and TTE was positive in 26 (20%; absolute difference 43.4% [95% CI, 35.2%-52.0%]; P<0.001). On prespecified secondary analysis, large RLS was detected by raTCD in 35 subjects (27%) versus 13 (10%) by TTE (absolute difference 17.0% [95% CI, 11.5%-24.5%]; P<0.001). There were no serious adverse events. CONCLUSIONS: raTCD was safe and ≈3 times more likely to diagnose RLS than TTE. TTE completely missed or underdiagnosed two thirds of large shunts diagnosed by raTCD. The raTCD device, used by health professionals with no prior TCD training, may allow providers to achieve the known sensitivity of TCD for RLS and patent foramen ovale detection without the need for an experienced operator to perform the test. Pending confirmatory studies, TCD appears to be the superior screen for RLS compared with TTE (funded by NeuraSignal). REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04604015.

Diagnosis and management of vertebrobasilar insufficiency.

OPINION STATEMENT: Understanding the anatomical pathways and clinical presentations for VBI are of the utmost importance due to the potential mimics that may occur. After identification of the entity, imaging must be performed to identify the etiology. Distinguishing external compression of the vertebral artery from intrinsic vascular disease due to atherosclerosis or dissection is critical to aid the clinician in the therapeutic decision tree. Patients with an external compression due to an osteophyte may benefit from definitive surgical decompression and excision of the bony structure. Patients with extracranial disease of the vertebral artery who have failed maximal medical therapy may benefit from angioplasty and stenting which appears to carry a low morbidity. Extracranial vertebral artery dissections can be treated with medical therapy using anti-platelet agents or on occasion anti-coagulation. Rarely, endovascular options are required if a patient is having hemodynamic stroke or TIAs due to flow failure. In such circumstances, stenting and angioplasty may be considered. Intracranial atherosclerosis is best managed with maximal medical therapy due to the high rate of complications attributable to stenting and angioplasty.

Homonymous hemianopia in nonketotic hyperglycemia is an ictal phenomenon.

Extended video-EEG or 18F-fluorodeoxyglucose PET (FDG-PET) was obtained in 3 adult patients with hemianopia secondary to nonketotic hyperglycemia. Two male patients presented with left hemianopia and episodic left gaze deviation and one male patient presented with right hemianopia and visual hallucinations. None of the 3 patients had a history of seizures or known epilepsy risk factors. All 3 patients were found to have elevated serum glucose (267 mg/dL, 320 mg/dL, and 487 mg/dL) without acidosis or urine ketones. In all 3 patients, video-EEG recorded recurrent ictal discharges originating from the posterior quadrant contralateral to their hemianopia. In 2 patients, FDG-PET demonstrated corresponding focal areas of hypermetabolism. Resolution of visual symptoms was achieved with antiepileptic drugs, hydration, and tight glycemic control.

High-frequency cortical stimulation augments recovery of thalamocortical oscillations from hypoxia in rat brain slices.

OBJECTIVES: Cerebrovascular hypoxia results in severe impairment and electrical dysfunction of cortical and thalamic neuronal networks. Typically cellular electrical activity returns if reoxygenation is established within 5-8 min. Electrical stimulation has been shown to reduce cellular apoptosis following cerebral hypoxia in animal models and clinical case reports. In this study, we wanted to analyze the electrophysiological repercussions of electrical stimulation on recovery of spontaneous thalamocortical oscillations (TCOs) following hypoxia in a thalamocortical slice preparation. MATERIALS AND METHODS: A hypoxia model of rat thalamocortical brain slices was used in which spontaneous TCO and cortical oscillation (CO) activity could be tracked with extracellular and intracellular recording techniques. Spontaneous TCO and CO activity was recorded prior to, during, and after hypoxia was induced in 15 brain slices. Bipolar, high-frequency stimulation (100 µsec, 150 Hz, 3 V) of somatosensory cortex was applied immediately after reoxygenation of slices was started and its effect on return of TCO activity compared with non-stimulated slices. RESULTS: Depolarization and suppression of extracellular TCOs and COs were demonstrated following the induction of hypoxia. TCO activity was lost after an average of 2.7 ± 0.5 min of hypoxia, whereas COs activity remained for an additional 3.2 ± 0.3 min in the presence of hypoxia. After loss of both TCOs and COs, oxygenated perfusate was restarted and TCOs spontaneously recovered in 6.8 ± 0.42 min. When 10 sec of high-frequency cortical stimulation was applied at the beginning of oxygenated perfusion, TCOs were observed to recover within 2.8 ± 0.76 min. If oxygenated perfusate was not restarted within 2 min following loss of either TCOs or COs, no recovery was seen. CONCLUSIONS: High-frequency cortical stimulation accelerated the recovery of thalamocortical network activity following hypoxia and reperfusion. Insight into the underlying mechanisms of this effect may enhance therapeutic interventions related to hypoxia following ischemic stroke.

A systematic review of stenting and angioplasty of symptomatic extracranial vertebral artery stenosis.

BACKGROUND AND PURPOSE: Extracranial vertebral artery stenosis (ECVAS) is common among patients with ischemic stroke. Despite the limited knowledge of the natural history of patients with symptomatic vertebral disease, endovascular revascularization techniques are now utilized in clinical practice. We sought to determine the risk of endovascular treatment for ECVAS with a systematic review of the literature. METHODS: A search strategy was used using the terms "stenting," "vertebral," "ostium," "origin," and "extracranial" through Medline. All articles were reviewed along with their references to determine the risk and durability of endovascular treatment. RESULTS: A total of 27 articles were identified that met inclusion criterion, with a total of 980 of 993 patients treated with stents. The majority of patients (56%) were noted to have contralateral vertebral artery stenosis or occlusion and 92% were symptomatic at the time of treatment. A total of 11 patients (1.1%) experienced a stroke and 8 (0.8%) experienced a transient ischemic attack within 30 days of the procedure. Drug-eluting stents were associated with lower restenosis rates (11%) compared to bare metal stents (30%) at a mean of 24 months of follow-up. CONCLUSIONS: Stenting and angioplasty of ECVAS appear to have a low rate of periprocedural stroke or transient ischemic attack and restenosis rates that may not be as high as suspected. Given the frequency of ECVAS as an etiology for ischemic stroke, future studies aimed at determining efficacy of this treatment modality relative to medical therapy would be of benefit to clinicians caring for these patients.

FDG-PET in the diagnosis of complex partial status epilepticus originating from the frontal lobe.

Complex partial status epilepticus of frontal origin can manifest as nonconvulsive behavioral symptoms that mimic psychiatric illness and, thus, may elude timely diagnosis. The diagnosis can be further delayed by absence of ictal activity on scalp electroencephalography when the ictal origin is orbitofrontal or mesial frontal. We describe the case of a 51-year-old woman with clinically subtle complex partial status epilepticus of left orbitofrontal origin, lacking any clear ictal pattern on the electroencephalogram, who was finally diagnosed using positron emission tomography with [(18)F]fluorodeoxyglucose (FDG-PET). Subsequent FDG-PET following 5 days of oxcarbazepine therapy demonstrated resolution of the left orbitofrontal hypermetabolic focus. FDG-PET is a potentially useful modality for diagnosing nonconvulsive status epilepticus that is not evident on electroencephalography.