Diffusion MR imaging acquisition and analytics for microstructural delineation in pre-clinical models of TBI.

Significant progress has been made toward improving both the acquisition of clinical diffusion-weighted imaging (DWI) data and its analysis in the uninjured brain, through various techniques including a large number of model-based solutions that have been proposed to fit for multiple tissue compartments, and multiple fibers per voxel. While some of these techniques have been applied to clinical traumatic brain injury (TBI) research, the majority of these technological enhancements have yet to be fully implemented in the preclinical arena of TBI animal model-based research. In this review, we describe the requirement for preclinical, MRI-based efforts to provide systematic confirmation of the applicability of some of these models as indicators of tissue pathology within the injured brain. We review how current DWI techniques are currently being used in animal TBI models, and describe how both acquisition and analytic techniques could be extended to leverage the progress made in clinical work. Finally, we highlight remaining gaps in the preclinical pipeline from data acquisition to final analysis that currently have no real, preclinical-based correlate.

The New Classes of Synthetic Illicit Drugs Can Significantly Harm the Brain: A Neuro Imaging Perspective with Full Review of MRI Findings.

Synthetic drugs contain substances that are pharmacologically similar to those found in traditional illicit drugs. Some of the most commonly abused synthetic drugs include synthetic marijuana, bath salts, ecstasy, N-bomb, methamphetamine and anabolic steroids. Many of them share the same chemical properties and physiologic responses with the drugs they mimic and may exaggerate the pathologic response in the brain leading to addiction. These drugs have detrimental (and often irreversible) effects on the brain and primarily affect the central nervous system by two mechanisms: 1) Neural hyper stimulation via increasing activation of certain neurotransmitters (norepinephrine, dopamine, and serotonin), 2) Cause significant reduction in CNS neural connectivity affecting various brain regions such as the basal ganglia, hippocampus, cerebellum, parietal lobe, and globus pallidus. Furthermore these drugs sometimes have severe, life-threatening adverse effects on the human body. A few structural MRI studies have been conducted in synthetic drug abusers to reveal the effects of these drugs on the brain parenchyma. This review article will describe the potential brain imaging findings in synthetic drug abusers as demonstrated by several case reports and the primary literature.

Diffusional kurtosis imaging of the developing brain.

BACKGROUND AND PURPOSE: Diffusional kurtosis imaging is an extension of DTI but includes non-Gaussian diffusion effects, allowing more comprehensive characterization of microstructural changes during brain development. Our purpose was to use diffusional kurtosis imaging to measure age-related microstructural changes in both the WM and GM of the developing human brain. MATERIALS AND METHODS: Diffusional kurtosis imaging was performed in 59 subjects ranging from birth to 4 years 7 months of age. Diffusion metrics, fractional anisotropy, and mean kurtosis were collected from VOIs within multiple WM and GM structures and subsequently analyzed with respect to age. Diffusional kurtosis tractography images at various stages of development were also generated. RESULTS: Fractional anisotropy and mean kurtosis both showed age-related increases in all WM regions, reflecting progression of diffusional anisotropy throughout development, predominantly in the first 2 years of life (eg, 70% and 157% increase in fractional anisotropy and mean kurtosis, respectively, from birth to 2 years for the splenium). However, mean kurtosis detected continued microstructural changes in WM past the fractional anisotropy plateau, accounting for more delayed isotropic changes (eg, 90% of maximum fractional anisotropy was reached at 5 months, whereas 90% of maximum mean kurtosis occurred at 18 months for the external capsule). Mean kurtosis may also provide greater characterization of GM maturation (eg, the putamen showed no change in fractional anisotropy but an 81% change in mean kurtosis from birth to 4 years 7 months). CONCLUSIONS: Mean kurtosis detects significant microstructural changes consistent with known patterns of brain maturation. In comparison with fractional anisotropy, mean kurtosis may offer a more comprehensive evaluation of age-related microstructural changes in both WM and GM and is potentially a valuable technique for studying brain development.

Global survey of national tuberculosis drug policies.

SETTING: National tuberculosis (TB) programmes (NTPs) in 100 countries. OBJECTIVES: To evaluate the relationship between the estimated prevalence of multidrug resistance in previously untreated TB cases and policies regarding sales and distribution of TB drugs, particularly rifampicin (RMP). DESIGN: Questionnaire survey of national TB drug control policies, completed by NTP managers. Results were correlated with recent World Health Organization estimates of prevalence of drug resistance in new cases of TB. RESULTS: Questionnaires were received from 100 countries, including 88 low- and middle-income countries (LMICs) and 17 of the 22 high-burden countries. Current policies were considered adequate in only 40 of the 88 LMICs (45%). A higher prevalence of multidrug resistance was associated with fewer years of free availability of TB drugs from the NTP (P = 0.02) and more years of availability of RMP from providers or pharmacies outside the NTP (P = 0.02). Eleven of the 20 countries with the highest prevalence of multidrug resistance had inadequate policies governing sales and distribution of TB drugs. CONCLUSIONS: These findings suggest that policies regarding sales and distribution of TB drugs should receive more emphasis as part of the global strategy to control drug resistance.

Pseudoaneurysm of inferior epigastric artery complicating ileostomy construction.

Pseudoaneurysm of the inferior epigastric artery complicating ileostomy construction is described in a 25-year-old woman. She underwent total abdominal perineal proctocolectomy with a permanent ileostomy constructed through the right rectus muscle. 15 days later, she abruptly developed significant bleeding through the ileostomy that recurred two more times. Endoscopy performed through the ileostomy stoma revealed a small ulcer 8 cm from the stomal opening. The distal segment of ileum containing the bleeding site was resected, and on-table examination of the lesion revealed an underlying tear in the inferior epigastric artery wall. The patient recovered after the operation.