Optic Nerve Sheath Diameter Point-of-Care Ultrasonography Quality Criteria Checklist: An International Consensus Statement on Optic Nerve Sheath Diameter Imaging and Measurement.

OBJECTIVES: To standardize optic nerve sheath diameter (ONSD) point-of-care ultrasonography (POCUS) and improve its research and clinical utility by developing the ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC). DESIGN: Three rounds of modified Delphi consensus process and three rounds of asynchronous discussions. SETTING: Online surveys and anonymous asynchronous discussion. SUBJECTS: Expert panelists were identified according to their expertise in ONSD research, publication records, education, and clinical use. A total of 52 panelists participated in the Delphi process. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Three Delphi rounds and three asynchronous discussion rounds generated consensus on quality criteria (QC). This started with 29 QC in addition to other QC proposed by expert panelists. The QC items were categorized into probe selection, safety, body position, imaging, measurement, and research considerations. At the conclusion of the study, 28 QC reached consensus to include in the final ONSD POCUS QCC. These QC were then reorganized, edited, and consolidated into 23 QC that were reviewed and approved by the panelists. CONCLUSIONS: ONSD POCUS QCC standardizes ONSD ultrasound imaging and measurement based on international consensus. This can establish ONSD ultrasound in clinical research and improve its utility in clinical practice.

Acanthamoeba spp. and Balamuthia mandrillaris leading to fatal granulomatous amebic encephalitis.

Acanthamoeba spp. and Balamuthia mandrillaris are free-living amebae known to cause disseminated and fatal central nervous system dysfunction which manifests as granulomatous amebic encephalitis (GAE) with exceedingly rare frequency. We report two lethal cases of infection with free-living amebae: an acute case of Acanthamoeba spp. infection in an immunocompromised female and a subacute case of B. mandrillaris in a Hispanic male. The Acanthamoeba spp. infection presented with an atypical lesion in the thalamus that caused rapid deterioration of the patient while the case of B. mandrillaris had a prolonged clinical course with multifocal lesions beginning in the frontal lobe. Cerebrospinal fluid results were non-specific in both cases, however, post-mortem histology demonstrated the presence of trophozoites along a perivascular distribution of necrosis and infiltrate composed primarily of neutrophils. In addition to detailing the clinical presentations of these infrequent amebic infections, we offer insight into the difficulties surrounding their diagnoses in order to aid the clinician in accurate and timely identification.

Imaging of Carotid Dissection.

PURPOSE OF REVIEW: Here, we describe the four primary imaging modalities for identification of carotid artery dissection, advantages, limitations, and clinical considerations. In addition, imaging characteristics of carotid dissection associated with each modality will be described. RECENT FINDINGS: Recent advances in etiopathogenesis describe the genetic factors implicated in cervical artery dissection. MRI/MRA (magnetic resonance angiography) with fat suppression is regarded as the best initial screening test to detect dissection. Advances in magnetic resonance imaging for the diagnosis of dissection include the use of susceptibility-weighted imaging (SWI) for the detection of intramural hematoma and multisection motion-sensitized driven equilibrium (MSDE), which causes phase dispersion of blood spin using a magnetic field to suppress blood flow signal and obtain 3D T1- or T2*-weighted images. Digital subtraction angiography (DSA) remains the gold standard for identifying and characterizing carotid artery dissections. Carotid artery dissection is the result of a tear in the intimal layer of the carotid artery. This leads to a "double lumen" sign comprised of the true vessel lumen and the false lumen created by the tear. The most common presentation of carotid artery dissection is cranial and/or cervical pain ipsilateral to the dissection. However, severe neurological sequelae such as embolic ischemic stroke, intracranial hemorrhage, and subarachnoid hemorrhage can also result from carotid artery dissection. Carotid artery dissection can be identified by a variety of different imaging modalities including computed tomographic angiography (CTA), MRI, carotid duplex imaging (CDI), and digital subtraction angiography (DSA).

Imaging of Central Nervous System Hemorrhage.

OBJECTIVE: This article aims to familiarize the reader with the various types of nontraumatic central nervous system (CNS) hemorrhage and the various neuroimaging modalities used to help diagnose and manage them. LATEST DEVELOPMENTS: According to the 2019 Global Burden of Diseases, Injuries, and Risk Factors Study, intraparenchymal hemorrhage accounts for 28% of the global stroke burden. In the United States, hemorrhagic stroke makes up 13% of all strokes. The incidence of intraparenchymal hemorrhage increases substantially with age; thus, despite improvements in blood pressure control through various public health measures, the incidence is not decreasing as the population ages. In fact, in the most recent longitudinal study of aging, autopsy findings showed intraparenchymal hemorrhage and cerebral amyloid angiopathy in 30% to 35% of patients. ESSENTIAL POINTS: Rapid identification of CNS hemorrhage, which includes intraparenchymal hemorrhage, intraventricular hemorrhage, and subarachnoid hemorrhage, requires either head CT or brain MRI. Once hemorrhage is identified on the screening neuroimaging study, the pattern of blood in conjunction with the history and physical examination can guide subsequent neuroimaging, laboratory, and ancillary tests as part of the etiologic assessment. After determination of the cause, the chief aims of the treatment regimen are reducing hemorrhage expansion and preventing subsequent complications such as cytotoxic cerebral edema, brain compression, and obstructive hydrocephalus. In addition, nontraumatic spinal cord hemorrhage will also be briefly discussed.

Neuro-ultrasonography.

Transcranial Doppler ultrasonography (TCD) is a noninvasive, bedside, portable tool for assessment of cerebral hemodynamics. Modern TCD head frames allow continuous hands-free emboli detection for risk stratification and assessment of treatment efficacy in several cardiovascular diseases. Identifying a focal stenosis, arterial occlusion, and monitoring the treatment effect of intravenous tissue plasminogen activator can easily be accomplished by assessing TCD waveforms and determining prestenotic and poststenotic mean flow velocities. TCD is an excellent screening tool for vasospasm in aneurysmal subarachnoid hemorrhage. The use of intraoperative TCD during carotid endarterectomy and stenting allows optimal intraoperative hemodynamic management. Other applications are also discussed.

Imaging of Hemorrhagic Stroke.

PURPOSE OF REVIEW: Hemorrhagic stroke comprises approximately 15% to 20% of all strokes. This article provides readers with an understanding of the indications and significance of various neuroimaging techniques available for patients presenting with hemorrhagic strokes of distinct causes. RECENT FINDINGS: The most common initial neuroimaging study is a noncontrast head CT, which allows for the identification of hemorrhage. Once an intracranial hemorrhage has been identified, the pattern of blood and the patient's medical history, neurologic examination, and laboratory studies lead the practitioner to pursue further neuroimaging studies to guide the medical, surgical, and interventional management. Given that hemorrhagic stroke constitutes a heterogeneous collection of diagnoses, the subsequent neuroimaging pathway necessary to better evaluate and care for these patients is variable based on the etiology.With an increasing incidence and prevalence of atrial fibrillation associated with the aging population and the introduction of three new direct factor Xa inhibitors and one direct thrombin inhibitor to complement vitamin K antagonists, oral anticoagulant use continues to increase. Patients on oral anticoagulants have a sevenfold to tenfold increased risk for intracerebral hemorrhage (ICH). Furthermore, patients who have an ICH associated with oral anticoagulant use have a higher mortality rate than those with primary ICH. Despite the reduced incidence of hypertension-related ICH over the past decade, it is expected that the incidence of ICH will continue to increase. SUMMARY: Neuroimaging studies are integral to the identification of hemorrhagic stroke, determination of the underlying etiology, prevention of hematoma expansion, treatment of acute complications, and treatment of the underlying etiology, if indicated. Neuroimaging is essential for prognostication and thus directly impacts patient care.

SIRPIDs: prevalence and outcome in critically ill patients.

PURPOSE: To determine the prevalence, associated factors, and outcomes of critically ill patients with stimulus-induced rhythmic, periodic, or ictal discharges (SIRPIDs) on long-term video-EEG (VEEG). METHODS: After IRB approval, we retrospectively reviewed patient characteristics and VEEG findings of all consecutive critical care unit patients who underwent VEEG monitoring between January 2012 and September 2012. RESULTS: The prevalence of SIRPIDs was 12.1% (4 of 33 patients; exact 95% confidence interval, 3.4%-28.2%). Factors associated with SIRPIDs versus non-SIRPIDs patients included a higher prevalence of subclinical status epilepticus (100% vs. 17.2%, P = 0.003), longer total VEEG recording time (286 vs. 56.9 hours, P = 0.0004), and acute traumatic brain injury (75.0% vs. 17.2%, P = 0.036). Sex, age, a history of epilepsy, nonstatus epileptic seizures, other EEG periodic patterns, and background rhythm reactivity on VEEG did not correlate with the presence of SIRPIDs. The presence or absence of SIRPIDs had no bearing on outcome; however, the population studied was very small. CONCLUSIONS: This small series suggests that the presence of subclinical status epilepticus and traumatic brain injury correlated with the presence of SIRPIDs signifying that SIRPIDs may be due to a more focal etiology and may represent a more ictal pattern than previously thought. Longer recording times in those patient populations may yield more cases of SIRPIDs in which to base further studies.