Technology and Tool Development for BACPAC: Qualitative and Quantitative Analysis of Accelerated Lumbar Spine MRI with Deep-Learning Based Image Reconstruction at 3T.

Objectives: To evaluate whether combining fast acquisitions with deep-learning reconstruction can provide diagnostically useful images and quantitative assessment comparable to standard-of-care acquisitions for lumbar spine magnetic resonance imaging (MRI).

Methods: Eighteen patients were imaged with both standard protocol and fast protocol using reduced signal averages, each protocol including sagittal fat-suppressed T2-weighted, sagittal T1-weighted, and axial T2-weighted 2D fast spin-echo sequences. Fast-acquisition data was additionally reconstructed using vendor-supplied deep-learning reconstruction with three different noise reduction factors.

APOE Genotype Modifies the Association of Fusiform Gyrus Cerebral Metabolic Rate of Oxygen Consumption and Object Naming Performance.

Background: The apolipoprotein E (APOE) ɛ4 allele confers risk for age and Alzheimer's disease related cognitive decline but the mechanistic link remains poorly understood. Blood oxygenation level dependent (BOLD) response in the fusiform gyrus (FG) during object naming appears greater among APOEɛ4 carriers even in the face of equivalent cognitive performance, suggesting neural compensation. However, BOLD is susceptible to known age and APOE-related vascular changes that could confound its interpretation.

Cerebrovascular reactivity measurements using simultaneous O-water PET and ASL MRI: Impacts of arterial transit time, labeling efficiency, and hematocrit.

Cerebrovascular reactivity (CVR) reflects the capacity of the brain to meet changing physiological demands and can predict the risk of cerebrovascular diseases. CVR can be obtained by measuring the change in cerebral blood flow (CBF) during a brain stress test where CBF is altered by a vasodilator such as acetazolamide. Although the gold standard to quantify CBF is PET imaging, the procedure is invasive and inaccessible to most patients.

The Cerebral Blood Flow Biomedical Informatics Research Network (CBFBIRN) data repository.

Arterial spin labeling (ASL) MRI provides an accurate and reliable measure of cerebral blood flow (CBF). A rapidly growing number of CBF measures are being collected both in clinical and research settings around the world, resulting in a large volume of data across a wide spectrum of study populations and health conditions. Here, we describe a central CBF data repository with integrated processing workflows, referred to as the Cerebral Blood Flow Biomedical Informatics Research Network (CBFBIRN).

Increased cerebral blood flow associated with better response inhibition in bipolar disorder.

Impairment on inhibitory tasks has been well documented in bipolar disorder (BD). Differences in cerebral blood flow (CBF) between BD patients and healthy comparison (HC) participants have also been reported. Few studies have examined the relationship between cognitive performance and regional CBF in this patient population.

Elevated cerebrovascular resistance index is associated with cognitive dysfunction in the very-old.

Introduction: Age-related vascular changes, including blood pressure elevation and cerebral blood flow (CBF) reduction, are associated with cognitive decline and Alzheimer's disease (AD). Evidence suggests that the relationship between blood pressure and dementia risk varies between younger and older samples within the elderly population.

Methods: We examined the relationship between mean arterial pressure (MAP), CBF, and cognition in young-old (60 to 75 years of age) versus very-old (80+ years of age) adults.

The Cerebral Blood Flow Biomedical Informatics Research Network (CBFBIRN) database and analysis pipeline for arterial spin labeling MRI data.

Arterial spin labeling (ASL) is a magnetic resonance imaging technique that provides a non-invasive and quantitative measure of cerebral blood flow (CBF). After more than a decade of active research, ASL is now emerging as a robust and reliable CBF measurement technique with increased availability and ease of use. There is a growing number of research and clinical sites using ASL for neuroscience research and clinical care.

Altered cerebral perfusion in executive, affective, and motor networks during adolescent depression.

Objective: Although substantial literature has reported regional cerebral blood flow (rCBF) abnormalities in adults with depression, these studies commonly necessitated the injection of radioisotopes into subjects. The recent development of arterial spin labeling (ASL), however, allows noninvasive measurements of rCBF. Currently, no published ASL studies have examined cerebral perfusion in adolescents with depression.

Interaction of age and APOE genotype on cerebral blood flow at rest.

We investigated the impact of APOE genotype on cerebral blood flow (CBF) in older and younger adults. Forty cognitively normal older adults (16 ε4 carriers, 24 non-ε4 carriers) and 30 younger adults (15 ε4 carriers, 15 non-ε4 carriers) completed a resting-state whole-brain pulsed arterial spin labeling magnetic resonance scan. Main effects of aging were demonstrated wherein older adults had decreased gray matter CBF corrected for partial volume effects compared to younger adults in widespread brain regions.

Sustained high-altitude hypoxia increases cerebral oxygen metabolism.

Acute mountain sickness (AMS) is a common condition occurring within hours of rapid exposure to high altitude. Despite its frequent occurrence, the pathophysiological mechanisms that underlie the condition remain poorly understood. We investigated the role of cerebral oxygen metabolism (CMR(O(2))) in AMS.

Effect of mild cognitive impairment and APOE genotype on resting cerebral blood flow and its association with cognition.

Using whole-brain pulsed arterial spin labeling magnetic resonance imaging, resting cerebral blood flow (CBF) was measured in 20 mild cognitive impairment (MCI; 11 ɛ3 and 9 ɛ4) and 40 demographically matched cognitively normal (CN; 27 ɛ3 and 13 ɛ4) participants. An interaction of apolipoprotein (APOE) genotype (ɛ3 and ɛ4) and cognitive status (CN and MCI) on quantified gray-matter CBF corrected for partial volume effects was found in the left parahippocampal and fusiform gyri (PHG/FG), right middle frontal gyrus, and left medial frontal gyrus. In the PHG/FG, CBF was elevated for CN ɛ4 carriers but decreased for MCI ɛ4 carriers.

Computer-controlled, MR-compatible foot-pedal device to study dynamics of the muscle tendon complex under isometric, concentric, and eccentric contractions.

Purpose: To design a computer-controlled, magnetic resonance (MR)-compatible foot pedal device that allows in vivo mapping of changes in morphology and in strain of different musculoskeletal components of the lower leg under passive, isometric, concentric, and eccentric contractions.

Materials And Methods: A programmable servomotor in the control room pumped hydraulic fluid to rotate a foot-pedal inside the magnet. To validate the performance of the device, six subjects were imaged with gated velocity-encoded phase-contrast (VE-PC) imaging to investigate the dynamics of muscle and aponeurotic structures.

Pseudocontinuous arterial spin labeling with optimized tagging efficiency.

The adiabatic inversion of blood in pseudocontinuous arterial spin labeling (PCASL) is highly sensitive to off-resonance effects and gradient imperfections and this sensitivity can lead to tagging efficiency loss and unpredictable variations in cerebral blood flow estimates. This efficiency loss is caused by a phase tracking error between the RF pulses and the flowing spins. This article introduces a new method, referred to as Optimized PCASL (OptPCASL), that minimizes the phase tracking error by applying an additional compensation RF phase term and in-plane gradients to the PCASL pulse train.

Reduction in tendon elasticity from unloading is unrelated to its hypertrophy.

Tendinous tissues respond to chronic unloading with adaptive changes in mechanical, elastic, and morphological properties. However, little is known about the changes in the detailed structures of the entire tendinous tissue and whether the change in tendon stiffness is related to morphology. We investigated changes in dimensional (volume, cross-sectional area, segmented lengths) and elastic (Young's modulus) properties of the Achilles tendon and distal aponeurosis in response to chronic unilateral lower limb suspension (ULLS) using velocity encoded phase contrast (VE-PC) and three-dimensional morphometric magnetic resonance imaging (MRI).

Finite element modeling reveals complex strain mechanics in the aponeuroses of contracting skeletal muscle.

A finite element model was used to investigate the counter-intuitive experimental observation that some regions of the aponeuroses of a loaded and contracting muscle may shorten rather than undergo an expected lengthening. The model confirms the experimental findings and suggests that pennation angle plays a significant role in determining whether regions of the aponeuroses stretch or shorten. A smaller pennation angles (25 degrees ) was accompanied by aponeurosis lengthening whereas a larger pennation angle (47 degrees ) was accompanied by mixed strain effects depending upon location along the length of the aponeurosis.

In vivo intramuscular fascicle-aponeuroses dynamics of the human medial gastrocnemius during plantarflexion and dorsiflexion of the foot.

Velocity-encoded phase-contrast magnetic resonance (MR) imaging techniques and a computer-controlled MR-compatible foot pedal device were used to investigate the medial gastrocnemius muscle and aponeurosis deformations during passive and active eccentric movements of the plantarflexors. Intrafascicular strain, measured as the ratio of strain in the fascicle segment at its insertion to strain at its origin, was nonuniform along the proximodistal axis of the muscle (P < 0.01), progressively increasing from the proximal to distal direction.

Characterization and prognostic value of persistent hyponatremia in patients with severe heart failure in the ESCAPE Trial.

Background: Mild hyponatremia is relatively common in patients hospitalized with heart failure (HF). To our knowledge, the association of hyponatremia with outcomes has not been evaluated in the context of in-hospital clinical course including central hemodynamics and changes in serum sodium level.

Methods: The ESCAPE trial (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness) was a randomized, controlled study designed to evaluate the utility of a pulmonary artery catheter plus clinical assessment vs clinical assessment alone in guiding therapy in patients hospitalized with New York Heart Association class IV HF due to systolic dysfunction (left ventricular ejection fraction <30%).

Prognostic value of blood urea nitrogen in patients hospitalized with worsening heart failure: insights from the Acute and Chronic Therapeutic Impact of a Vasopressin Antagonist in Chronic Heart Failure (ACTIV in CHF) study.

Background: Hospitalization for acute decompensated heart failure (ADHF) is associated with a high postdischarge mortality and readmission rate. The association between baseline blood urea nitrogen (BUN) and clinical outcomes in patients admitted for ADHF was evaluated in a post-hoc analysis of the ACTIV in CHF trial.

Methods And Results: Patients were categorized into quartiles according to baseline BUN.

Improvement in hyponatremia during hospitalization for worsening heart failure is associated with improved outcomes: insights from the Acute and Chronic Therapeutic Impact of a Vasopressin Antagonist in Chronic Heart Failure (ACTIV in CHF) trial.

Background: Hyponatremia predicts poor outcome in patients with acute heart failure syndromes. This study evaluated the relationship between baseline serum sodium, change in serum sodium, and 60-day mortality in hospitalized heart failure patients.

Methods: A post-hoc analysis of the ACTIV in CHF trial was performed.

Early pharmacological treatment of acute heart failure syndromes: a systematic review of clinical trials.

Context: Acute Heart Failure Syndromes (AHFS) is a common admission diagnosis associated with high mortality and hospital readmissions. Given the mixed results of recent clinical trials, the early management of AHFS remains controversial.

Objective: To review the recent evidence regarding current and investigational therapies for the early management of AHFS.

Review of current and investigational pharmacologic agents for acute heart failure syndromes.

Acute heart failure syndromes (AHFS) are a major public health problem and present a therapeutic challenge to clinicians. Commonly used agents in the treatment of AHFS include diuretics, vasodilators (eg, nitroglycerin, nitroprusside, nesiritide), and inotropes (eg, dobutamine, dopamine, milrinone). Patients admitted to hospital with AHFS and low cardiac output state (AHFS/LO) represent a subgroup with very high inhospital and postdischarge mortality rates.

Approach to the patient with bicuspid aortic valve and ascending aorta aneurysm.

Bicuspid aortic valve (BAV) disease is a common congenital heart valve abnormality accounting for a large number of valve replacements in the United States. Although still incompletely understood, the natural history of BAV disease is severe aortic stenosis and associated ascending aortic dilatation. In addition to the increased risk of endocarditis, aortic dissection and severe aortic valve dysfunction are responsible for most fatal complications.

Are the American College of Cardiology/Emergency Cardiac Care (ACC/ECC) guidelines useful in triaging patients to telemetry units?

Purpose: To determine if the ACC/ECC guidelines (1991) properly stratify patients according to risk of arrhythmia, defined as a single event on cardiac monitoring, and benefit, defined as a subsequent management change from a recorded telemetry event.

Subjects And Methods: In 2003, a prospective study of 217 consecutive patients admitted to a 24-bed telemetry unit was conducted for 25 days at a major academic hospital. Patients were categorized per ACC/ECC guidelines as appropriate (class I & II) or inappropriate (class III) based on a non-cardiologist admission diagnosis.

Congestion is an important diagnostic and therapeutic target in heart failure.

Most hospitalizations for acute heart failure syndrome (AHFS) are related to clinical congestion as a result of high left ventricular diastolic pressure (LVDP) rather than to low cardiac output. Patients frequently develop "hemodynamic congestion" (high LVDP) several days to weeks before the onset of symptoms and signs of clinical congestion. By the time symptoms and signs are evident, patients generally require hospitalization.

Aortoduodenal fistula and associated rupture of abdominal aortic aneurysm after endoluminal stent graft repair.

The main complications of endovascular repair of abdominal aortic aneurysms are vascular leaks and rupture, although infection and aortoduodenal fistulas have also been reported rarely. We report a case of aortoduodenal fistula with separate retroperitoneal rupture of an abdominal aortic aneurysm after endovascular stent graft repair. The initial implantation was uneventful, without any leaks at 1 month.