Manganese-enhanced magnetic resonance imaging for in vivo assessment of damage and functional improvement following spinal cord injury in mice.

In past decades, much effort has been invested in developing therapies for spinal injuries. Lack of standardization of clinical read-out measures, however, makes direct comparison of experimental therapies difficult. Damage and therapeutic effects in vivo are routinely evaluated using rather subjective behavioral tests. Here we show that manganese-enhanced magnetic resonance imaging (MEMRI) can be used to examine the extent of damage following spinal cord injury (SCI) in mice in vivo. Injection of MnCl2 solution into the cerebrospinal fluid leads to manganese uptake into the spinal cord. Furthermore, after injury MEMRI-derived quantitative measures correlate closely with clinical locomotor scores. Improved locomotion due to treating the detrimental effects of SCI with an established therapy (neutralization of CD95Ligand) is reflected in an increase of manganese uptake into the injured spinal cord. Therefore, we demonstrate that MEMRI is a sensitive and objective tool for in vivo visualization and quantification of damage and functional improvement after SCI. Thus, MEMRI can serve as a reproducible surrogate measure of the clinical status of the spinal cord in mice, potentially becoming a standard approach for evaluating experimental therapies.     

Magnetic resonance imaging using hyperpolarized He-gas

Rationale and Objectives. Current imaging procedures of the lung concentrate on visualization of morphology. Computed tomography is the imaging method of choice for the majority of pulmonary diseases. Functional data are commonly obtained from arterial blood gas analysis, spirometry, and body plethysmography, which all suffer from lack of regional information.Materials and Methods. Magnetic resonance imaging (MRI) of the lung has been advanced recently by the use of hyperpolarized ³He as a new contrast mechanism. Four different image acquisition modes are performed during a typical patient study.Results. ³He-MRI yields functional information about the lung with a high spatial and temporal resolution, avoiding the risks of ionizing radiation. The method is currently limited by high costs and restricted availability of the gas.Conclusion. In this article, the experience obtained at the University of Mainz, being Europe’s most experienced center performing ³He-MRI in humans, is reviewed against the international background.     

MRI of the lungs using hyperpolarized noble gases.

The nuclear spin polarization of the noble gas isotopes (3)He and (129)Xe can be increased using optical pumping methods by four to five orders of magnitude. This extraordinary gain in polarization translates directly into a gain in signal strength for MRI. The new technology of hyperpolarized (HP) gas MRI holds enormous potential for enhancing sensitivity and contrast in pulmonary imaging. This review outlines the physics underlying the optical pumping process, imaging strategies coping with the nonequilibrium polarization, and effects of the alveolar microstructure on relaxation and diffusion of the noble gases. It presents recent progress in HP gas MRI and applications ranging from MR microscopy of airspaces to imaging pulmonary function in patients and suggests potential directions for future developments.     

Myoglobin plasma level related to muscle mass and fiber composition – a clinical marker of muscle wasting?

Progressive muscle wasting is a central feature of cancer-related cachexia and has been recognized as a determinant of poor prognosis and quality of life. However, until now, no easily assessable clinical marker exists that allows to predict or to track muscle wasting. The present study evaluated the potential of myoglobin (MG) plasma levels to indicate wasting of large locomotor muscles and, moreover, to reflect the loss of MG-rich fiber types, which are most relevant for daily performance. In 17 cancer-cachectic patients (weight loss 22%) and 27 age- and gender-matched healthy controls, we determined plasma levels of MG and creatine kinase (CK), maximal quadriceps muscle cross-sectional area (CSA) by magnetic resonance imaging, muscle morphology and fiber composition in biopsies from the vastus lateralis muscle, body cell mass (BCM) by impedance technique as well as maximal oxygen uptake (VO(2)max). In cachectic patients, plasma MG, muscle CSA, BCM, and VO(2)max were 30-35% below control levels. MG showed a significant positive correlation to total muscle CSA (r = 0.65, p < 0.001) and to the CSA fraction formed by type 1 and 2a fibers (r = 0.80, p < 0.001). However, when adjusted for body height and age by multiple regression, MG yielded a largely improved prediction of total CSA (multiple r = 0.83, p < 0.001) and of fiber type 1 and 2a CSA (multiple r = 0.89, p < 0.001). The correlations between CK and these muscle parameters were weaker, and elevated CK values were observed in 20% of control subjects despite a prior abstinence from exercise for 5 days. In conclusion, plasma MG, when adjusted for anthropometric parameters unaffected by weight, may be considered as a novel marker of muscle mass (CSA) indicating best the mass of MG-rich type 1 and 2a fibers as well as VO(2)max as an important functional readout. CK plasma levels appear to be less reliable because prolonged increases are observed in even subclinical myopathies or after exercise. Notably, cancer-related muscle wasting was not associated with increases in plasma MG or CK in this study.     

Lung Screening Benefits and Challenges: A Review of The Data and Outline for Implementation

Lung cancer is the leading cause of cancer-related deaths worldwide, accounting for almost a fifth of all cancer-related deaths. Annual computed tomographic lung cancer screening (CTLS) detects lung cancer at earlier stages and reduces lung cancer-related mortality among high-risk individuals. Many medical organizations, including the U.S. Preventive Services Task Force, recommend annual CTLS in high-risk populations. However, fewer than 5% of individuals worldwide at high risk for lung cancer have undergone screening. In large part, this is owing to delayed implementation of CTLS in many countries throughout the world. Factors contributing to low uptake in countries with longstanding CTLS endorsement, such as the United States, include lack of patient and clinician awareness of current recommendations in favor of CTLS and clinician concerns about CTLS-related radiation exposure, false-positive results, overdiagnosis, and cost. This review of the literature serves to address these concerns by evaluating the potential risks and benefits of CTLS. Review of key components of a lung screening program, along with an updated shared decision aid, provides guidance for program development and optimization. Review of studies evaluating the population considered “high-risk” is included as this may affect future guidelines within the United States and other countries considering lung screening implementation.     

Microwave Ablation of Porcine Kidneys in vivo: Effect of two Different Ablation Modes (“Temperature Control” and “Power Control”) on Procedural Outcome

Purpose

This study was designed to analyze the effect of two different ablation modes (“temperature control” and “power control”) of a microwave system on procedural outcome in porcine kidneys in vivo.

Methods

A commercially available microwave system (Avecure Microwave Generator; MedWaves, San Diego, CA) was used. The system offers the possibility to ablate with two different ablation modes: temperature control and power control. Thirty-two microwave ablations were performed in 16 kidneys of 8 pigs. In each animal, one kidney was ablated twice by applying temperature control (ablation duration set point at 60 s, ablation temperature set point at 96°C, automatic power set point; group I). The other kidney was ablated twice by applying power control (ablation duration set point at 60 s, ablation temperature set point at 96°C, ablation power set point at 24 W; group II). Procedural outcome was analyzed: (1) technical success (e.g., system failures, duration of the ablation cycle), and (2) ablation geometry (e.g., long axis diameter, short axis diameter, and circularity).

Results

System failures occurred in 0% in group I and 13% in group II. Duration of the ablation cycle was 60 ± 0 s in group I and 102 ± 21 s in group II. Long axis diameter was 20.3 ± 4.6 mm in group I and 19.8 ± 3.5 mm in group II (not significant (NS)). Short axis diameter was 10.3 ± 2 mm in group I and 10.5 ± 2.4 mm in group II (NS). Circularity was 0.5 ± 0.1 in group I and 0.5 ± 0.1 in group II (NS).

Conclusions

Microwave ablations performed with temperature control showed fewer system failures and were finished faster. Both ablation modes demonstrated no significant differences with respect to ablation geometry.     

Influence of cholesterol and fat in food on indirect parameters of exocrine pancreatic function.

Fecal elastase 1, chymotrypsin activity, and fat content in stool are clinical parameters of exocrine pancreatic function. The aim of this study was to clarify the possible impact of extreme changes in diet on fecal enzyme concentration/activity, since extreme diets may lead to wrong conclusions in the diagnosis of pancreatic insufficiency. Twelve healthy test persons followed 4 diet phases, each with a duration of 6 days. The 4 diet phases were (1) nearly fat-free with a low-cholesterol content; (2) high in fat and low in cholesterol; (3) high in cholesterol deriving from meat, and (4) high in cholesterol deriving from eggs. At the end of each diet phase, a 72-hour stool collection was carried out to measure fecal elastase 1, chymotrypsin and fecal fat content. The results showed no significant changes after each of the 4 diet phases. The clinical parameters of fecal elastase 1 and chymotrypsin activity in stool do not seem to be significantly influenced by fat and cholesterol deriving from food.