Neurosurgical laser ablation and MR thermometry: Risks of multisite workflow pattern.

Neurosurgical laser ablation is a relatively new but rapidly growing application of stereotactic neurosurgery that allows neurosurgeons to treat many previously untreatable conditions with the added benefit of shorter hospitalizations and recovery times. The vast majority of these procedures, however, are performed using a multisite workflow pattern involving transport of the patient between the operating room (OR), the computed tomography (CT) suite, and the magnetic resonance imaging (MRI) suite, often necessitating patient transfer through public pathways and requiring multiple trips if laser fiber placement is not accurate. There are significant risks posed to the patient with this practice and no existing guidelines addressing it.

Thalamic DBS with a constant-current device in essential tremor: A controlled clinical trial.

Introduction: This study of thalamic deep brain stimulation (DBS) investigated whether a novel constant-current device improves tremor and activities of daily living (ADL) in patients with essential tremor (ET).

Methods: A prospective, controlled, multicenter study was conducted at 12 academic centers. We investigated the safety and efficacy of unilateral and bilateral constant-current DBS of the ventralis intermedius (VIM) nucleus of the thalamus in patients with essential tremor whose tremor was inadequately controlled by medications.

PET/MRI: Where might it replace PET/CT?

Unlabelled: Simultaneous positron emission tomography and MRI (PET/MRI) is a technology that combines the anatomic and quantitative strengths of MR imaging with physiologic information obtained from PET. PET and computed tomography (PET/CT) performed in a single scanning session is an established technology already in widespread and accepted use worldwide. Given the higher cost and complexity of operating and interpreting the studies obtained on a PET/MRI system, there has been question as to which patients would benefit most from imaging with PET/MRI versus PET/CT.

Future of Family Medicine Faculty Development in Sub-Saharan Africa.

Background And Objectives: High-quality family medicine education is needed in sub-Saharan Africa to facilitate the future growth of primary care health systems. Current faculty educators recognize the value of dedicated teacher training and ongoing faculty development. However, they are constrained by inadequate faculty development program availability and institutional support.

Current Status of Family Medicine Faculty Development in Sub-Saharan Africa.

Background And Objectives: Reducing the shortage of primary care physicians in sub-Saharan Africa requires expansion of training programs in family medicine. Challenges remain in preparing, recruiting, and retaining faculty qualified to teach in these pioneering programs. Little is known about the unique faculty development needs of family medicine faculty within the sub-Saharan African context.

Dicarboxylic acids as pH sensors for hyperpolarized C magnetic resonance spectroscopic imaging.

Imaging tumoral pH may help to characterize aggressiveness, metastasis, and therapeutic response. We report the development of hyperpolarized [2-C,D]diethylmalonic acid, which exhibits a large pH-dependent C chemical shift over the physiological range. We demonstrate that co-polarization with [1-C,D]tert-butanol accurately measures pH viaC NMR and magnetic resonance spectroscopic imaging in phantoms.

Topical safety and vasoconstrictive assay-based bioequivalence of a new reformulated mometasone cream.

Objectives: A new improved mometasone furoate (Elocon™) cream with an emulsification system that produces a stable emulsion has been developed. In order to register the product in various markets, it was essential to ensure the cream was topically well tolerated and that it was bioequivalent to the reference product.

Methods: Phase I clinical studies were performed to assess the local safety and tolerability upon multiple dosing of this new cream as well as to assess the single-dose bioequivalence relative to the marketed product.

Quantitative Evaluation of Atlas-based Attenuation Correction for Brain PET in an Integrated Time-of-Flight PET/MR Imaging System.

Purpose To assess the patient-dependent accuracy of atlas-based attenuation correction (ATAC) for brain positron emission tomography (PET) in an integrated time-of-flight (TOF) PET/magnetic resonance (MR) imaging system. Materials and Methods Thirty recruited patients provided informed consent in this institutional review board-approved study. All patients underwent whole-body fluorodeoxyglucose PET/computed tomography (CT) followed by TOF PET/MR imaging.

Family Medicine Global Health Fellowship Competencies: A Modified Delphi Study.

Background And Objectives: Many US medical schools and family medicine departments have responded to a growing interest in global health by developing global health fellowships. However, there are no guidelines or consensus statements outlining competencies for global health fellows. Our objective was to develop a mission and core competencies for Family Medicine Global Health Fellowships.

Imaging of the rabbit supraspinatus enthesis at 7 Tesla: a 4-week time course after repair surgery and effect of channeling.

Purpose: To image the supraspinatus enthesis reformation of rabbit shoulders by magnetic resonance at 7 Tesla (T) using T2 mapping after surgical repair and to assess the effects of channeling aimed at enhancing enthesis reformation.

Materials And Methods: In 112 rabbits, the distal supraspinatus (SSP) tendon was unilaterally detached and reattached after 1 week. At the first surgery, channeling was performed at the footprint in 64 rabbits.

Hybrid ZTE/Dixon MR-based attenuation correction for quantitative uptake estimation of pelvic lesions in PET/MRI.

Purpose: This study introduces a new hybrid ZTE/Dixon MR-based attenuation correction (MRAC) method including bone density estimation for PET/MRI and quantifies the effects of bone attenuation on metastatic lesion uptake in the pelvis.

Methods: Six patients with pelvic lesions were scanned using fluorodeoxyglucose (18F-FDG) in an integrated time-of-flight (TOF) PET/MRI system. For PET attenuation correction, MR imaging consisted of two-point Dixon and zero echo-time (ZTE) pulse sequences.

Monitoring acute metabolic changes in the liver and kidneys induced by fructose and glucose using hyperpolarized [2- C]dihydroxyacetone.

Purpose: To investigate acute changes in glucose metabolism in liver and kidneys in vivo after a bolus injection of either fructose or glucose, using hyperpolarized [2- C]dihydroxyacetone.

Methods: Spatially registered, dynamic, multislice MR spectroscopy was acquired for the metabolic products of [2- C]dihydroxyacetone in liver and kidneys. Metabolism was probed in 13 fasted rats at three time points: 0, 70, and 140 min.

Atazanavir increases the plasma concentrations of 1200 mg raltegravir dose.

Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice-daily (b.i.d.

Optimizing Flip Angles for Metabolic Rate Estimation in Hyperpolarized Carbon-13 MRI.

Hyperpolarized carbon-13 magnetic resonance imaging has enabled the real-time observation of perfusion and metabolism in vivo. These experiments typically aim to distinguish between healthy and diseased tissues based on the rate at which they metabolize an injected substrate. However, existing approaches to optimizing flip angle sequences for these experiments have focused on indirect metrics of the reliability of metabolic rate estimates, such as signal variation and signal-to-noise ratio.

Novel Gastroretentive Controlled Release Formulations for Once-Daily Administration: Assessment of Clinical Feasibility and Formulation Concept for Raltegravir.

Background: Raltegravir is an integrase strand transfer inhibitor indicated in combination with other anti-retroviral medicinal products for the treatment of HIV-1 infection, given twice daily. Although a BCS class II compound, raltegravir exhibits low colonic absorption, thus making development of modified release formulations challenging. It was hypothesized that a gastroretentive (GR) formulation would increase trough (C) concentrations of raltegravir, hence being amenable to a once-daily (QD) regimen.

Spectrally selective three-dimensional dynamic balanced steady-state free precession for hyperpolarized C-13 metabolic imaging with spectrally selective radiofrequency pulses.

Purpose: Balanced steady-state free precession (bSSFP) sequences can provide superior signal-to-noise ratio efficiency for hyperpolarized (HP) carbon-13 ( C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP C metabolites with high spatiotemporal resolution.

Theory And Methods: This novel approach for bSSFP spectral selectivity incorporates optimized short-duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts.

Effect of metal-cation antacids on the pharmacokinetics of 1200 mg raltegravir.

Objectives: Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once-daily regimen (QD) at a dose of 1200 mg is under development. The effect of calcium carbonate and magnesium/aluminium hydroxide antacids on the pharmacokinetics of a 1200 mg dose of raltegravir was assessed in this study.

Mis-estimation and bias of hyperpolarized apparent diffusion coefficient measurements due to slice profile effects.

Purpose: The purpose of this work was to explore the impact of slice profile effects on apparent diffusion coefficient (ADC) mapping of hyperpolarized (HP) substrates.

Methods: Slice profile effects were simulated using a Gaussian radiofrequency (RF) pulse with a variety of flip angle schedules and b-value ordering schemes. A long T water phantom was used to validate the simulation results, and ADC mapping of HP [ C, N ]urea was performed on the murine liver to assess these effects in vivo.

Efavirenz does not meaningfully affect the single dose pharmacokinetics of 1200 mg raltegravir.

Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once daily regimen (QD) at a dose of 1200 mg (2 x 600 mg) is under development and offers a new treatment option for HIV-1 infected treatment-naive subjects. Since raltegravir is eliminated mainly by metabolism via an UDP-glucuronosyltransferase (UGT) 1 A1-mediated glucuronidation pathway, co-administration of UGT1A1 inducers may alter plasma levels of raltegravir.

An unexpectedly high rate of revisions and removals in deep brain stimulation surgery: Analysis of multiple databases.

Introduction: Deep brain stimulation (DBS) is an established therapy for movement disorders, and is under active investigation for other neurologic and psychiatric indications. While many studies describe outcomes and complications related to stimulation therapies, the majority of these are from large academic centers, and results may differ from those in general neurosurgical practice.

Methods: Using data from both the Centers for Medicare and Medicaid Services (CMS) and the National Surgical Quality Improvement Program (NSQIP), we identified all DBS procedures related to primary placement, revision, or removal of intracranial electrodes.

Imaging Renal Urea Handling in Rats at Millimeter Resolution using Hyperpolarized Magnetic Resonance Relaxometry.

spin spin relaxation time () heterogeneity of hyperpolarized [C,N]urea in the rat kidney was investigated. Selective quenching of the vascular hyperpolarized C signal with a macromolecular relaxation agent revealed that a long- component of the [C,N]urea signal originated from the renal extravascular space, thus allowing the vascular and renal filtrate contrast agent pools of the [C,N]urea to be distinguished via multi-exponential analysis. The response to induced diuresis and antidiuresis was performed with two imaging agents: hyperpolarized [C,N]urea and a control agent hyperpolarized bis-1,1-(hydroxymethyl)-1-C-cyclopropane-H.

Separation of extra- and intracellular metabolites using hyperpolarized (13)C diffusion weighted MR.

This work demonstrates the separation of extra- and intracellular components of glycolytic metabolites with diffusion weighted hyperpolarized (13)C magnetic resonance spectroscopy. Using b-values of up to 15,000smm(-2), a multi-exponential signal response was measured for hyperpolarized [1-(13)C] pyruvate and lactate. By fitting the fast and slow asymptotes of these curves, their extra- and intracellular weighted diffusion coefficients were determined in cells perfused in a MR compatible bioreactor.

Spinal Subdural Abscess Following Laminectomy for Symptomatic Stenosis: A Report of 2 Cases and Review of the Literature.

BACKGROUND Spinal subdural abscesses, also known as empyemas, are rare infectious lesions, the exact incidence of which is unknown. Presentation is typically dramatic, with back pain, fever, motor, and sensory deficits. Rapid identification and surgical intervention with laminectomy, durotomy, and washout provides the best outcomes.