Vol 48, No 6 (2017)

The purpose of this study was to evaluate the sensitivities of quantitative susceptibility mapping (QSM) and R2* mapping in clinical diagnoses of Parkinson’s disease (PD). QSM images and R2* maps from 29 patients with PD and 25 healthy controls were obtained on a clinical 3T magnetic resonance imaging (MRI) system using a three-dimensional multi-echo gradient-echo sequence. Two-tailed t tests and receiver operating characteristic curves analyses were applied to the mean values of QSM and R2* of the two groups. In the PD group, a two-tailed Pearson correlation analysis was used to investigate the correlations between MRI measures (susceptibility and R2* values) and the Unified Parkinson’s Disease Rating Scale-III (UPDRS-III) score. In the substantia nigra (SN), a significant difference between patients with PD and healthy controls was found on QSM (154.80 ± 43.36 vs. 127.50 ± 21.05 ppb, P = 0.006) but not on R2* mapping. The receiver operating characteristic curves showed that QSM was more sensitive than R2* mapping to distinguish PD patients from healthy controls, with areas under the curve equal to 0.68 and 0.51, respectively. The UPDRS-III motor scores did not correlate with mean susceptibility or R2* values in the PD group. In conclusion, QSM is a more accurate and sensitive method than R2* mapping to detect the pathologic changes in the SN of patients with PD.

With promising applications of superparamagnetic iron oxide nanoparticles (SPIO) in magnetic resonance imaging (MRI) and targeted monitoring of molecular and cellular processes, many different samples of these nanoparticles (NPs) with different compositions synthesized each year. The main challenge in this way is to generate enough contrast that could be traceable on images. In order to compensate for the low quantity of contrast agents in desired sites, surface engineering has to be done to enhance relaxation rates. As many factors such as magnetic field strength can affect relaxation rates of NPs, knowledge of the relation between field strength and relaxation rates is essential to compare results of different fields and choosing an optimum agent for a specific field. In this study, we evaluate the effects of magnetic field strengths of 0.35, 1.5, and 3 T on relaxation rates of PEGylated SPIOs. Longitudinal and transverse relaxation rates of all samples with various concentrations were analyzed quantitatively on appropriate spin–echo sequences. Our results suggest that the increasing of the field strength leads to a marked decrease of longitudinal relaxivity. In the case of transverse relaxivity, all NPs showed an increase between 0.35 and 1.5 T. Upon further increasing the field strength, relaxation rates only slightly increased except for two samples that showed saturation.

Virtually every corrosion detection method reports only the presence of a material phase that denotes probable corrosion, not its spectral signature. A signature specific to the type of iron oxide corrosion product would not only confirm the presence of corrosion but also provide insight into the environment of its formation. To identify the unique spectral signature of a commonly occurring corrosion product, goethite (α-FeOOH), we performed high-resolution terahertz (THz) absorption loss measurements on a polycrystalline mineral sample of goethite, scanning from 0.045 to 1.5 THz. We report two distinct temperature-dependent absorption peaks that extend from 4.2 to 425 K. By combining X-ray diffraction and magnetic characterization on this large crystallite-sized goethite sample, we derived a Neél transition temperature of 435 K, below which the sample is antiferromagnetic. We interpret these absorption peaks as magnon transitions of the antiferromagnetic resonances, allowing precise identification of goethite, a common iron corrosion product and geological mineral, via two terahertz absorption peaks over this temperature range. This measurement technique has the potential for detecting iron-bearing oxides originating from corrosion occurring underneath layers of polymeric products and other protective coatings that can be easily penetrated by electromagnetic waves with frequencies on the order of 1 THz. Furthermore, the combined X-ray and magnetic characterization of this sample, which had a large crystallite size, also improved the previously established relationship between the Néel transition temperature and the inverse mean crystallite dimension in the [111] direction. Our results provide end-case peaks which, compared with goethite samples of smaller crystallite size and purity, will enable the extension of this non-destructive evaluation technique to real corrosion applications.

7-Ethyl-2,3-diglutathionyl-6-hydroxynaphthazarin (GluNaz, 1a) can be a protector of the rat brain under ischemia. The effect of hydroxynaphtazarin derivative 1a was estimated. The focal ischemia by occlusion of middle cerebral artery (MCAo) was used. Conjugate 1a kept life of more then 30% of rats after treatment. Studied compounds did not render additional changes of arterial pressure before and within 3 h after operation. The injection of 1a in a concentration exceeding a therapeutic dose more than by ten times did not lead to an increase in heart rate in intact animals. The behavioral reactions of rats after occlusion showed an increase of cognitive frustration. Like 7-ethyl-2,3,6-trihydroxynaphthazarin (Ech, 1b) (Russian Pat. RU 2266737, 1999 [3]), GluNaz reduced the region of cytotoxic edema in rat brain after treatment. The recovering effect of 1a begins to improve within 48 h and 1b—within 72 h. Magnetic resonance imaging allows a detailed dynamic study of the effect of the compounds in our model of an ischemic stroke. So, the conjugate 1a studied can be potential medicine for the treatment of ischemic injury of a brain.

The purpose of this study was to investigate the usefulness of medical magnetic resonance spectroscopy analysis methods for assessment of edible oil rancidity. The four edible oils including soybean oil, olive oil, grape seed oil, and sunflower oil were selected for evaluating rancidity (cooking counts/time, exposure time in air). The total lipid ((–CH₂–)_n/noise), total saturated fatty acid (TSFA), total unsaturated fatty acid (TUSFA), total unsaturated bond (TUSB), and polyunsaturated bond (PUSB) were quantified by separating each peak area of –CH₃, (–CH₂–)_n, –CH₂–C=C–CH₂–, =C–CH₂–C=, and –CH=CH– by –CH₃ by ¹H-magnetic resonance spectroscopy (MRS) analysis. The change in fatty acid (bond) according to the cooking counts/time increased for all fatty acids (bond) in soybean oil and grape seed oil. In olive oil, all fatty acids (bond) decreased overall, while sunflower oil showed a decrease in TSFA and PUSB and an increase in TUSFA and TUSB. The soybean, grape seed, and sunflower oils showed increased TUSB, TUSFAB, and PUSB with exposure to air after cooking once, while olive oil showed hardly any changes in fatty acids according to the exposure time to air after cooking. It will be necessary to choose a method that minimizes changes in fatty acids by fully understanding the characteristics of the selected edible oil to prevent not only a change in fatty acids during cooking, but also an increase in TSFA.