State of Practice on Transcranial MR-Guided Focused Ultrasound: A Report from the ASNR Standards and Guidelines Committee and ACR Commission on Neuroradiology Workgroup.

Transcranial focused ultrasound (FUS) is a versatile, MR-guided, incisionless intervention with diagnostic and therapeutic applications for neurologic and psychiatric diseases. It is currently FDA-approved as a thermoablative treatment of essential tremor and Parkinson disease. However, other applications of FUS including BBB opening for diagnostic and therapeutic applications, sonodynamic therapy, histotripsy, and low-intensity focused ultrasound neuromodulation are all in clinical trials.

Monitoring Blood-Brain Barrier Opening in Rats with a Preclinical Focused Ultrasound System.

The brain has a highly selective semipermeable blood barrier, termed the blood-brain barrier (BBB), which prevents the delivery of therapeutic macromolecular agents to the brain. The integration of MR-guided low-intensity pulsed focused ultrasound (FUS) with microbubble pre-injection is a promising technique for non-invasive and non-toxic BBB modulation. MRI can offer superior soft-tissue contrast and various quantitative assessments, such as vascular permeability, perfusion, and the spatial-temporal distribution of MRI contrast agents.

Beyond the Buzz: Cortical and subcortical brain changes in patients with pulsatile tinnitus.

Pulsatile tinnitus (PT) can be a debilitating condition characterized by rhythmic, heartbeat-synchronous sounds, which can severely impact patients' quality of life. Understanding the neuroanatomical changes in PT patients may provide critical insights into the impacts of this condition. This study aimed to investigate potential differences in cortical and subcortical brain volume between adults with PT and age-matched controls (60 to 70 years of age).

Volumetric hyperthermia delivery using the ExAblate Body MR-guided focused ultrasound system.

Objectives: To investigate image-guided volumetric hyperthermia strategies using the ExAblate Body MR-guided focused ultrasound ablation system, involving mechanical transducer movement and sector-vortex beamforming.

Materials And Methods: Acoustic and thermal simulations were performed to investigate volumetric hyperthermia using mechanical transducer movement combined with sector-vortex beamforming, specifically for the ExAblate Body transducer. The system control in the ExAblate Body system was modified to achieve fast transducer movement and MR thermometry-based hyperthermia control, mechanical transducer movements and electronic sector-vortex beamforming were combined to optimize hyperthermia delivery.

Arteriovenous shunts of the cervical spine: patient demographics, presentation, patterns of high-risk venous drainage, and updated classification.

Background: Intracranial dural arteriovenous (AV) fistula classifications focus on presence/absence of retrograde flow in the cortical veins of the brain as this angiographic finding portends a worse prognosis. However, prior categorization systems of AV shunts in the spine do not incorporate these features. We propose an updated classification for spinal shunting lesions that terms any shunting lesion with retrograde flow in any cortical vein of the brain or spinal cord medullary vein as "high risk".

Strategies to Improve Drug Delivery Across the Blood-Brain Barrier for Glioblastoma.

Purpose Of Review: Glioblastoma remains resistant to most conventional treatments. Despite scientific advances in the past three decades, there has been a dearth of effective new treatments. New approaches to drug delivery and clinical trial design are needed.

Technical advances in motion-robust MR thermometry.

Proton resonance frequency shift (PRFS) MR thermometry is the most common method used in clinical thermal treatments because of its fast acquisition and high sensitivity to temperature. However, motion is the biggest obstacle in PRFS MR thermometry for monitoring thermal treatment in moving organs. This challenge arises because of the introduction of phase errors into the PRFS calculation through multiple methods, such as image misregistration, susceptibility changes in the magnetic field, and intraframe motion during MRI acquisition.

MR Thermometry during Transcranial MR Imaging-Guided Focused Ultrasound Procedures: A Review.

Interest in transcranial MR imaging-guided focused ultrasound procedures has recently grown. These incisionless procedures enable precise focal ablation of brain tissue using real-time monitoring by MR thermometry. This article will provide an updated review on clinically applicable technical underpinnings and considerations of proton resonance frequency MR thermometry, the most common clinically used MR thermometry sequence.

Robotic Diagnostic Cerebral Angiography: A Multicenter Experience of 113 Patients.

Background: Neurointerventional robotic systems have potential to reduce occupational radiation, improve procedural precision, and allow for future remote teleoperation. A limited number of single institution case reports and series have been published outlining the safety and feasibility of robot-assisted diagnostic cerebral angiography.

Methods: This is a multicenter, retrospective case series of patients undergoing diagnostic cerebral angiography at three separate institutions - University of California, Davis (UCD); University of California, Los Angeles (UCLA); and University of California, San Francisco (UCSF).

Clinical evaluation of pulsatile tinnitus: history and physical examination techniques to predict vascular etiology.

Background: Pulsatile tinnitus (PT) may be due to a spectrum of cerebrovascular etiologies, ranging from benign venous turbulence to life threatening dural arteriovenous fistulas. A focused clinical history and physical examination provide clues to the ultimate diagnosis; however, the predictive accuracy of these features in determining PT etiology remains uncertain.

Methods: Patients with clinical PT evaluation and DSA were included.

Transitional vascular anomaly of a persistent medial procephalic vein causing obstructive hydrocephalus and intracranial haemorrhage.

We report a case of obstructive hydrocephalus caused by a transitional (shunting) developmental venous anomaly not previously reported in the literature. Both thalami in this patient drain into a midline vein in the floor of the third ventricle that crosses the cerebral aqueduct and exerts mass effect. While this patient's hydrocephalus was managed by a ventriculoperitoneal shunt catheter, their hospital course was complicated by a spontaneous intraparenchymal bleed of the left thalamus thought to be caused by their vascular malformation.

Motion-robust, multi-slice, real-time MR thermometry for MR-guided thermal therapy in abdominal organs.

Purpose: To develop an effective and practical reconstruction pipeline to achieve motion-robust, multi-slice, real-time MR thermometry for monitoring thermal therapy in abdominal organs.

Methods: The application includes a fast spiral magnetic resonance imaging (MRI) pulse sequence and a real-time reconstruction pipeline based on multi-baseline proton resonance frequency shift (PRFS) method with visualization of temperature imaging. The pipeline supports multi-slice acquisition with minimal reconstruction lag.

Percutaneous sclerotherapy for head and neck lymphatic malformations in neonates and infants ≤12 months of age.

Background: Percutaneous sclerotherapy is an effective treatment for lymphatic malformations (LM) of the head and neck in adults. The purpose of this study was to examine the indications and efficacy of sclerotherapy for head/neck LM in the neonate and infant population.

Methods: We retrospectively reviewed patients treated with percutaneous sclerotherapy for LM of the head/neck at age ≤12 months at a single vascular anomalies clinic.

MRI-guided endovascular intervention: current methods and future potential.

Introduction: Image-guided endovascular interventions, performed using the insertion and navigation of catheters through the vasculature, have been increasing in number over the years, as minimally invasive procedures continue to replace invasive surgical procedures. Such endovascular interventions are almost exclusively performed under x-ray fluoroscopy, which has the best spatial and temporal resolution of all clinical imaging modalities. Magnetic resonance imaging (MRI) offers unique advantages and could be an attractive alternative to conventional x-ray guidance, but also brings with it distinctive challenges.

Cerebrovascular pulsatile tinnitus: causes, treatments, and outcomes in 164 patients with neuroangiographic correlation.

Background: Pulsatile tinnitus (PT) can cause significant detriment to quality of life and may herald a life-threatening condition. Endovascular evaluation is the gold standard for the definitive diagnosis of PT and facilitates treatment. However, no large study has determined the distribution of causes and treatment outcomes of PT evaluated endovascularly.

Intraoperative Angiogram Using C-Arm Fluoroscopy and Direct Common Carotid Artery Puncture During Surgical Treatment of Paraclinoid Aneurysms.

Background: Intraoperative angiography (IOA) has been shown to be a useful adjunct in surgical treatment of cerebral aneurysms. However, its use can be limited by hybrid operating room availability. On the other hand, the use of C-arm fluoroscopy can add challenges to IOA during navigation of the aortic arch and selection of the great vessels.

Pharyngo-tympano-stapedial middle meningeal artery variant supply to a falcotentorial dural arteriovenous fistula.

The pharyngo-tympano-stapedial middle meningeal artery (PTS-MMA) variant has been described in one case report and never in the setting of arterial supply to a dural arteriovenous fistula, to our knowledge. We report the case of a middle-aged patient with severe, daily headache who presented to our institution for angiography and treatment. CT angiography and MRI demonstrated an enlarged left middle meningeal artery coursing to a large venous varix in the falcotentorial region.

Endovascular Therapy for Intracranial Giant Cell Arteritis : Systematic Review, Technical Considerations and the Effect of Intra-arterial Calcium Channel Blockers.

Background: Giant cell arteritis (GCA) is a systemic vasculitis that may cause ischemic stroke. Rarely, GCA can present with aggressive intracranial stenoses, which are refractory to medical therapy. Endovascular treatment (EVT) is a possible rescue strategy to prevent ischemic complications in intracranial GCA but the safety and efficacy of EVT in this setting are not well-described.

Eptifibatide bridging therapy for staged carotid artery stenting and cardiac surgery: Safety and feasibility.

Background: Prophylactic carotid artery stenting (CAS) is an effective strategy to reduce perioperative stroke in patients with severe carotid stenosis who require cardiothoracic surgery (CTS). Staging both procedures (CAS-CTS) during a single hospitalization presents conflicting demands for antiplatelet therapy and the optimal pharmacologic strategy between procedures is not established. The purpose of this study is to present our initial experience with a "bridging" protocol for staged CAS-CTS.

Diagnostic Approach to Pulsatile Tinnitus: A Narrative Review.

Importance: Pulsatile tinnitus is a debilitating symptom affecting millions of Americans and can be a harbinger of hemorrhagic or ischemic stroke. Careful diagnostic evaluation of pulsatile tinnitus is critical in providing optimal care and guiding the appropriate treatment strategy.

Observations: An underlying cause of pulsatile tinnitus can be identified in more than 70% of patients with a thorough evaluation.