A Method for Imaging the Ischemic Penumbra with MRI using IVIM.

Background And Purpose: In acute ischemic stroke, the amount of "local" CBF distal to the occlusion, i.e. all blood flow within a region whether supplied antegrade or delayed and dispersed through the collateral network, may contain valuable information regarding infarct growth rate and treatment response.

Quantification of Collateral Supply with Local-AIF Dynamic Susceptibility Contrast MRI Predicts Infarct Growth.

Background And Purpose: In ischemic stroke, leptomeningeal collaterals can provide delayed and dispersed compensatory blood flow to tissue-at-risk despite an occlusion and can impact treatment response and infarct growth. The purpose of this work is to test the hypothesis that the inclusion of this delayed and dispersed flow with an appropriately calculated local arterial input function (local-AIF) is needed to quantify the degree of collateral blood supply in tissue distal to an occlusion.

Materials And Methods: Seven experiments were conducted in a preclinical middle cerebral artery occlusion model.

Flow augmentation therapies preserve brain network integrity and hemodynamics in a canine permanent occlusion model.

The acute phase of ischemic stroke presents a critical window for therapeutic intervention, where novel approaches such as hyper-acute cerebral flow augmentation offer promising avenues for neuroprotection. In this study, we investigated the effects of two such therapies, NEH (a combination of norepinephrine and hydralazine) and Sanguinate (pegylated bovine carboxyhemoglobin), on resting-state functional connectivity, global mean signal (GMS), and blood oxygen level-dependent (BOLD) time lag in a pre-clinical canine model of stroke via permanent occlusion of the middle cerebral artery (total of n = 40 IACUC-approved mongrel canines randomly split into control/natural history and two treatment groups). Utilizing group independent component analysis (ICA), we identified and examined the integrity of sensorimotor and visual networks both pre- and post-occlusion, across treatment and control groups.

Quantification of Collateral Supply with Local-AIF Dynamic Susceptibility Contrast MRI Predicts Infarct Growth.

Background And Purpose: In ischemic stroke, leptomeningeal collaterals can provide compensatory blood flow to tissue at risk despite an occlusion, and impact treatment response and infarct growth. The purpose of this work is to test the hypothesis that local perfusion with an appropriate Local Arterial Input Function (AIF) is needed to quantify the degree of collateral blood supply in tissue distal to an occlusion.

Materials And Methods: Seven experiments were conducted in a pre-clinical middle cerebral artery occlusion model.

Efficacy Assessment of Cerebral Perfusion Augmentation through Functional Connectivity in an Acute Canine Stroke Model.

Background And Purpose: Ischemic stroke disrupts functional connectivity within the brain's resting-state networks (RSNs), impacting recovery. This study evaluates the effects of norepinephrine and hydralazine (NEH), a cerebral perfusion augmentation therapy, on RSN integrity in a hyperacute canine stroke model.

Materials And Methods: Fifteen adult purpose-bred mongrel canines, divided into treatment and control (natural history) groups, underwent endovascular induction of acute middle cerebral artery occlusion (MCAO).

Quantitative perfusion and water transport time model from multi -value diffusion magnetic resonance imaging validated against neutron capture microspheres.

Purpose: Quantification of perfusion in ml/100 g/min, rather than comparing relative values side-to-side, is critical at the clinical and research levels for large longitudinal and multi-center trials. Intravoxel incoherent motion (IVIM) is a non-contrast magnetic resonance imaging diffusion-based scan that uses a multitude of -values to measure various speeds of molecular perfusion and diffusion, sidestepping inaccuracy of arterial input functions or bolus kinetics. Questions remain as to the original of the signal and whether IVIM returns quantitative and accurate perfusion in a pathology setting.

Quantitative perfusion and water transport time model from multi b-value diffusion magnetic resonance imaging validated against neutron capture microspheres.

Intravoxel Incoherent Motion (IVIM) is a non-contrast magnetic resonance imaging diffusion-based scan that uses a multitude of b-values to measure various speeds of molecular perfusion and diffusion, sidestepping inaccuracy of arterial input functions or bolus kinetics in quantitative imaging. We test a new method of IVIM quantification and compare our values to reference standard neutron capture microspheres across normocapnia, CO2 induced hypercapnia, and middle cerebral artery occlusion in a controlled animal model. Perfusion quantification in ml/100g/min compared to microsphere perfusion uses the 3D gaussian probability distribution and defined water transport time as when 50% of the molecules remain in the tissue of interest.

Augmentation of perfusion with simultaneous vasodilator and inotropic agents in experimental acute middle cerebral artery occlusion: a pilot study.

Background: This study tests the hypothesis that simultaneous cerebral blood pressure elevation and potent vasodilation augments perfusion to ischemic tissue in acute ischemic stroke and it varies by degree of pial collateral recruitment.

Methods: Fifteen mongrel canines were included. Subjects underwent permanent middle cerebral artery occlusion; pial collateral recruitment was scored before treatment.

Effect of early Sanguinate (PEGylated carboxyhemoglobin bovine) infusion on cerebral blood flow to the ischemic core in experimental middle cerebral artery occlusion.

Background: Sanguinate, a bovine PEGylated carboxyhemoglobin-based oxygen carrier with vasodilatory, oncotic and anti-inflammatory properties designed to release oxygen in hypoxic tissue, was tested to determine if it improves infarct volume, collateral recruitment and blood flow to the ischemic core in hyperacute middle cerebral artery occlusion (MCAO).

Methods: Under an IACUC approved protocol, 14 mongrel dogs underwent endovascular permanent MCAO. Seven received Sanguinate (8 mL/kg) intravenously over 10 min starting 30 min following MCAO and seven received a similar volume of normal saline.

QSM in canine model of acute cerebral ischemia: A pilot study.

Purpose: In the present study, we investigated the potential of QSM to assess the physiological state of cortical tissue in the middle cerebral artery occlusion canine model of a cerebral ischemia.

Methods: Experiments were performed in 8 anesthetized canines. Gradient echo, perfusion, and DWI data of brains at normal and ischemic states were acquired.

Influence of simultaneous pressor and vasodilatory agents on the evolution of infarct growth in experimental acute middle cerebral artery occlusion.

Background: This study sought to test the hypothesis that simultaneous central blood pressure elevation and potent vasodilation can mitigate pial collateral-dependent infarct growth in acute ischemic stroke.

Methods: Twenty mongrel canines (20-30 kg) underwent permanent middle cerebral artery occlusion (MCAO). Eight subjects received continuous infusion of norepinephrine (0.

Mechanical Thrombectomy for Patients with In-Hospital Ischemic Stroke: A Case-Control Study.

Background And Aim: Patients with in-hospital acute ischemic stroke (AIS) have, in general, worse outcomes compared to those presenting from the community, partly attributed to the numerous contraindications to intravenous thrombolysis. We aimed to identify and analyze a group of patients with in-hospital AIS who remain suitable candidates for acute endovascular therapies.

Methods: A retrospective 6-year data analysis was conducted in patients evaluated through the in-hospital stroke alert protocol in a single tertiary care university hospital to identify those with in-hospital AIS due to acute intracranial large vessel occlusion (ILVO).

Predictors for the extent of pial collateral recruitment in acute ischemic stroke.

Background: Pial arterioles can provide a variable degree of collateral flow to ischemic vascular territories during acute ischemic stroke. This study sought to identify predictive factors of the degree of pial collateral recruitment in acute ischemic stroke.

Methods: Clinical information and arteriograms from 62 consecutive patients with stroke due to either middle cerebral artery (MCA) M1 segment or internal carotid artery (ICA) terminus occlusion within 6 h following symptom onset were retrospectively reviewed.

High-Resolution MRI Microscopy Coil Assessment of Parotid Masses.

The goal of this study was to determine whether high-resolution magnetic resonance imaging (MRI) microscopy coil imaging can improve the depiction parotid masses. A total of 14 parotid masses, including 7 salivary neoplasms, 2 abnormal lymph nodes, and 5 benign cystic lesions were imaged with T2-weighted and fat-suppressed postcontrast T1-weighted sequences using a 47-mm diameter microscopy coil in addition to conventional MRI sequences acquired with a conventional head and neck neurovascular coil. Compared to conventional parotid MRI sequences, microscopy coil images provided better definition of the margins of neoplasms, provide more detailed definition of lymph node morphology, and better depict certain cyst contents in the superficial portions of the parotid gland.

Absolute quantitative MR perfusion and comparison against stable-isotope microspheres.

Purpose: This work sought to compare a quantitative T bookend dynamic susceptibility contrast MRI based perfusion protocol for absolute cerebral blood flow (qCBF) against CBF measured by the stable-isotope neutron capture microsphere method, a recognized reference standard for measuring tissue blood flow, at normocapnia, hypercapnia, and in acute stroke.

Methods: CBF was measured in anesthetized female canines by MRI and microspheres over 2 consecutive days for each case. On day 1, 5 canines were measured before and during a physiological challenge induced by carbogen inhalation; on day 2, 4 canines were measured following permanent occlusion of the middle cerebral artery.

Atorvastatin Treatment of Cavernous Angiomas with Symptomatic Hemorrhage Exploratory Proof of Concept (AT CASH EPOC) Trial.

Background: More than a million Americans harbor a cerebral cavernous angioma (CA), and those who suffer a prior symptomatic hemorrhage have an exceptionally high rebleeding risk. Preclinical studies show that atorvastatin blunts CA lesion development and hemorrhage through inhibiting RhoA kinase (ROCK), suggesting it may confer a therapeutic benefit.

Objective: To evaluate whether atorvastatin produces a difference compared to placebo in lesional iron deposition as assessed by quantitative susceptibility mapping (QSM) on magnetic resonance imaging in CAs that have demonstrated a symptomatic hemorrhage in the prior year.

MR Thermography-Guided Head and Neck Lesion Laser Ablation.

Interstitial laser ablation has been successfully used as a minimally invasive treatment option for tumors in many parts of the body, including the head and neck. In this article, we describe the use of MR imaging guidance and mapping sequences for accurate localization of the target lesion, percutaneous interstitial laser ablation methods, and the use of MR thermography for temperature monitoring during laser ablation, with a focus on applications in the head and neck region.

A printed information leaflet about MRI and radiologists improves neuroradiology patient health literacy.

Purpose: To determine the health literacy benefit of a printed informational leaflet for patients scheduled to undergo brain magnetic resonance imaging (MRI) scans.

Methods And Materials: A two-page leaflet that provided an overview of MRI and the role of radiologists was prepared and given to outpatients scheduled to undergo brain MRI examinations while in the waiting room. A survey composed mainly of yes/no and Likert scale questions pertaining to the leaflet, as well as patient demographics, was administered to the patients.

Educational Impact of Trainee-Facilitated Head and Neck Radiology-Pathology Correlation Conferences.

The goal of this study was to evaluate the benefits of resident and fellow-facilitated radiology-pathology head and neck conferences. A total of seven resident-facilitated and six fellow-facilitated head and neck radiology-pathology cases were presented as part of the radiology department conference series. The radiology residents were surveyed regarding the perceived quality and effectiveness of the fellow-facilitated sessions.

Fuzzy c-means segmentation of major vessels in angiographic images of stroke.

Patients suffering from ischemic stroke develop varying degrees of pial arterial supply (PAS), which can affect patient response to reperfusion therapy and risk of hemorrhage. Since vessel segmentation may be an important part in identifying PAS, we present a fuzzy c-means (FCM) clustering method to segment major vessels in x-ray angiograms. Our approach consists of semiautomatic region of interest (ROI) delineation, separation of major vessels from capillary blush and/or background noise through FCM clustering, and identification of the major vessel category.

Comparison between whole-body and head and neck neurovascular coils for 3-T magnetic resonance proton resonance frequency shift thermography guidance in the head and neck region.

The purpose of this study is to compare the image quality of magnetic resonance (MR) treatment planning images and proton resonance frequency (PRF) shift thermography images and inform coil selection for MR-guided laser ablation of tumors in the head and neck region. Laser ablation was performed on an agar phantom and monitored via MR PRF shift thermography on a 3-T scanner, following acquisition of T1-weighted (T1W) planning images. PRF shift thermography images and T2-weighted (T2W) planning images were also performed in the neck region of five normal human volunteers.