Amplitude of Low Frequency Fluctuation (ALFF) in the Cervical Spinal Cord with Stenosis: A Resting State fMRI Study

published_or_final_versio

Non-invasive MRI Assessments of Tissue Microstructures and Macromolecules in the Eye upon Biomechanical or Biochemical Modulation

published_or_final_versio

The epidemic of sexually transmitted infections in China: implications for control and future perspectives

China has experienced an increasing epidemic of sexually transmitted infections (STIs), including HIV. High risk groups likely to be infected include female sex workers (FSWs) and their clients, men who have sex with men (MSM), drug users and migrant workers. Prevention can be achieved through education of the population, condom promotion, early detection of symptomatic and asymptomatic people, and effective diagnosis and treatment of these patients and their partners. This article aims to describe the profile of the epidemic in high-risk groups in China as well as to detail the contributing factors and the implications for control. Programmes for the control of STIs should be immediate priorities in China, and primary and secondary prevention strategies are vital to this process

Nicotinic Receptors Underlying Nicotine Dependence: Evidence from Transgenic Mouse Models.

Nicotine underlies the reinforcing properties of tobacco cigarettes and e-cigarettes. After inhalation and absorption, nicotine binds to various nicotinic acetylcholine receptor (nAChR) subtypes localized on the pre- and postsynaptic membranes of cells, which subsequently leads to the modulation of cellular function and neurotransmitter signaling. In this chapter, we begin by briefly reviewing the current understanding of nicotine's actions on nAChRs and highlight considerations regarding nAChR subtype localization and pharmacodynamics. Thereafter, we discuss the seminal discoveries derived from genetically modified mouse models, which have greatly contributed to our understanding of nicotine's effects on the reward-related mesolimbic pathway and the aversion-related habenulo-interpeduncular pathway. Thereafter, emerging areas of research focusing on modulation of nAChR expression and/or function are considered. Taken together, these discoveries have provided a foundational understanding of various genetic, neurobiological, and behavioral factors underlying the motivation to use nicotine and related dependence processes, which are thereby advancing drug discovery efforts to promote long-term abstinence

Evolution of MR DTI changes in neonatal rats after mild hypoxic-ischemic insult

7-day-old mild hypoxic-ischemic (H-I) rats (n=12) were studied at 7T with diffusion tensor imaging (DTIs) in day 1, 3 and 7 post H-I insult. The apparent diffusion coefficient (ADC), fractional anisotropy (FA) and directional diffusivities (¦Ë// and ¦Ë¡Í) values were measured in white matter (WM) and gray matter (GM) lesion and their contralateral side. In day 1, the ADC, FA and ¦Ë// values showed significant decrease in GM lesion whilst WM lesion only showed a significant ADC increase. In day 3, the significant FA decrease and ¦Ë¡Í increase were found in GM lesion. Significant ADC and ¦Ë¡Í increase, and FA decrease were observed in the ipsilateral WM. By day 7, all DTI values were not statistically different between two hemispheres. Thus DTI is a sensitive method to study the early transient GM and WM changes after mild H-I insult by probing the microstructural changes

A free-breathing non-contrast-enhanced pulmonary magnetic resonance angiography at 3 Tesla

Background: The breathhold contrast-enhanced three-dimensional magnetic resonance angiography (MRA) using T1-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla. Methods: The time-of-flight protocol was based on a two-dimensional T1-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects. Results: Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of ∼300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20°-30°. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel. Conclusions: The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.link_to_OA_fulltex

Microstructural organization and macromolecular contents in fibrous tissues of normal and hypertensive eyes with diffusion tensor imaging and magnetization transfer imaging

Electronic Poster Session: Musculoskeletal - Bone & UTE: no. 4201The sclera and cornea are fibrous connective tissues in the outer coat of the eye which may undergo microscopic structural realignment and macromolecular changes in healthy aging and in diseases such as myopia, ocular hypertension and glaucoma. Recently, we demonstrated the use of the magic-angle effect to improve MRI sensitivity to reveal T2 and T2* relaxation changes in scleral and corneal tissues upon intraocular pressure loading. In this study, we further evaluated the corneoscleral shells using high-field DTI and MTI at the magic angle in order to test the hypotheses that (1) the microstructural organization and macromolecular contents of the sclera and cornea can be detected and differentiated with high-field MRI; and (2) acute ocular hypertension may alter DTI and MTI properties in these fibrous tissues

Magic angle enhanced MR microscopy of fibrous structures in normotensive and hypertensive eyes using T2, T2* and T1rho MRI

Traditional Poster Session - Musculoskeleta: MSK Misc.: no. 1265ISMRM Merit Award: Magna cum LaudeSclera is a fibrous connective tissue in the outer coat of the eye which may undergo microscopic structural reorganization under different physiological environments. Ocular hypertension may apply tensile stress to sclera leading to microstructural changes. However, there are limited non-invasive technique available. In this study, we demonstrated the feasibility of using magic angle enhanced MRI in different MR contrasts to detect magnetic tissue property changes in scleral fibers of and normotensive and hypertenive eyes.link_to_OA_fulltex