Creation of an MRI phantom based on super-paramagnetic nanoparticles of iron oxide (SPIO) for standardization of the conversion of T2 * values in the concentration of iron in the liver

In this study the standardization method for T2* maps acquisition on various MR scanners (3T and 1.5T) is proposed. The reproducibility of the obtained T2* values is realized through the MR-compatible phantom containing paramagnetic complex iron oxide nanoparticles. The repeatability of measurements results has shown that the created phantom retains all the required characteristics (homogeneity, stability of concentrations and manifested paramagnetic properties) over a long period of time. The application of standardized T2* values allows to use previously received T2*, [ms] to iron concentrations in the dry substance of the liver (LIC), [mg/ml] conversion formulas for accurate, fast and non-invasive MRI diagnostics of liver iron overload.

MRI Diagnostics of Intracranial hypotension Syndrome on the Example of Clinical Observation

Intracranial hypotension is a clinical and radiological syndrome, manifested by a decrease in the volume or pressure of the cerebrospinal fluid caused by various reasons, one of the main clinical manifestations of which are orthostatic headaches. The gold standard in the radiation diagnosis of this condition is magnetic resonance imaging (MRI). Increasing the awareness of radiologists about this pathology, its manifestations on MRI, will allow more often to diagnose this syndrome and choose the tactics of further treatment. This publication presents its own clinical observation — a patient with intracranial hypotension syndrome, on his example, MR and clinical manifestations are considered, and some data on the etiology and pathogenetic mechanisms of the described pathological process are also given.

A CT-free protocol to treat osteoid osteoma of the hip region in childhood and adolescence by percutaneous drilling and by hip arthroscopy

Introduction: It is often difficult to clinically and radiologically diagnose intra-articular osteoid osteomas and osteoid osteomas of the hip joint. Treatment can also be difficult due to complex locational relationships. CT-guided radiofrequency ablation is currently the standard form of treatment. In this paper we report on a minimally-invasive concept for treating osteoid osteomas near the hip joint in children and adolescents which does not involve using computed tomography. Material and method: 10 patients with an average age of 12.1 years underwent treatment for osteoid osteomas in the hip joint region. The diagnosis was made using a contrast-enhanced MRI. The osteoid osteomas were marked percutaneously using x-ray and MRI guidance. MRI-guided drilling/curettage was performed in 4 cases and arthroscopic resection in 6 cases. Results: All lesions were successfully treated using the MRI-guided method. All patients were free of pain after the treatment. There was no instance of recurrence during the follow-up period, which averaged 10 months. The effective dose for marking the lesion was between 0.0186 mSv and 0.342 mSV (mean 0.084 mSV). Conclusions: Our MRI diagnostics protocol, the MRI-guided drilling and the minimally invasive hip arthroscopy represent an alternative to CT-guided radiofrequency ablation in the treatment of osteoid osteomas. Radiation exposure can thereby be significantly reduced. Hip arthroscopy can also be used to treat secondary pathologies such as femoroacetabular impingement.

Magnetic nanoparticles for components of MRI diagnostics and electronic devices

The formation of single-phase solid solutions of iron oxide and manganese oxide with a spinel structure in MnxFe3 – xO4 system (x = 0; 0.3; 0.6; 0.8; 1.0; 1.2; 1.4; 1.8) has been established by methods of X-ray phase analysis and infrared spectroscopy. The maximum saturation magnetization was found for the composition Mn0.3 Fe2.7O4 (Ms = 68 A ⋅ m2 ⋅ kg−1 at 300 K and Ms = 85 A ⋅ m2 ⋅ kg−1 at 5 K), which is associated with a change in the cationic distribution over tetrahedral and octahedral voids. The materials obtained were stabilized in the form of colloidal solutions using a number of polyelectrolytes. It was found that poly(diallyldimethylammonium chloride) (PDDA) had the best stabilizing effect due to its structural features. A method for controlling the magnetic properties of magnetite by partial replacement of iron ions in the magnetite structure with manganese is proposed. Changing the magnitude of the magnetization and coercive force is possible by changing the degree of substitution. Relatively high values of specific magnetization, as well as uniformity of magnetic particles in size, can be of practical interest, for the manufacture of contrast agents in MRI diagnostics.

MRI-Diagnostics of Injuries and Diseases of the Ankle Joint and Foot (Review of Literature)

Summary. Diseases and injuries of the ankle joint and foot make up 6-12% of the total number of injuries and diseases of the musculoskeletal system. The article is devoted to the main diagnostic possibilities of magnetic resonance imaging (MRI), determination of indications for examination and protocols for the study of the ankle joint and foot. Based on the analysis of literature data, the high diagnostic efficiency of MRI in the identified pathologies of bone and soft tissue structures of this segment of the lower extremity was determined.

Spin-Dependent Phenomena in Semiconductor Micro-and Nanoparticles—From Fundamentals to Applications

The present overview of spin-dependent phenomena in nonmagnetic semiconductor microparticles (MPs) and nanoparticles (NPs) with interacting nuclear and electron spins is aimed at covering a gap between the basic properties of spin behavior in solid-state systems and a tremendous growth of the experimental results on biomedical applications of those particles. The first part of the review represents modern achievements of spin-dependent phenomena in the bulk semiconductors from the theory of optical spin orientation under indirect optical injection of carriers and spins in the bulk crystalline silicon (c-Si)—via numerous insightful findings in the realm of characterization and control through the spin polarization—to the design and verification of nuclear spin hyperpolarization in semiconductor MPs and NPs for magnetic resonance imaging (MRI) diagnostics. The second part of the review is focused on the electron spin-dependent phenomena in Si-based nanostructures, including the photosensitized generation of singlet oxygen in porous Si and design of Si NPs with unpaired electron spins as prospective contrast agents in MRI. The experimental results are analyzed by considering both the quantum mechanical approach and several phenomenological models for the spin behavior in semiconductor/molecular systems. Advancements and perspectives of the biomedical applications of spin-dependent properties of Si NPs for diagnostics and therapy of cancer are discussed.

ALBUMIN-COATED MAGNETIC NANOPARTICLES AS A UNIVERSAL NANOVEHICLE FOR TARGETED DELIVERY OF DIAGNOSTICAND THERAPEUTIC AGENTS TO MALIGNANT TISSUES

Albumin-coated iron oxide magnetic nanoparticles were designed and synthesized. It can act as contrast agents for MRI diagnostics of various tumors, as well as a nanovehicle for targeted delivery of chemotherapy and immunotherapy drugs.

Diagnostic methods used in children with malocclusion

Introduction. With advances in technology, there has been a need for more precise imaging methods which have become an integral part of the orthodontic treatment plan. Aim. The aim of this study is to present diagnostic methods that are currently used in children with malocclusion. Material and methods. The materials analysed in this review are articles from PubMed and Google Scholar. To identify relevant publications, the search was carried out using the key word combination: imaging, diagnostics, malocclusion, children, orthodontics. The number of 16 research papers in which these keywords appeared were qualified for this review. Results. According to the mentioned publications, pantomographic images are the most frequently recommended method for detecting dental anomalies. Cephalometry was used to observe changes in the facial axis and to measure the length of the jaw. CBCT is being used more and more often, mainly to identify possible prognostic factors in the case of canine retention/eruption in the maxilla. The method of magnetic resonance imaging was also compared with cephalometric images. Conclusions. 1. The pantomogram is a useful and frequently used method in the detection of craniofacial anomalies. 2. Cephalometry allows the effects of the treatment to be monitored. 3. CBCT is a significant diagnostic tool to assess the growth of craniofacial structures. 4. MRI diagnostics limits the patient’s exposure to harmful ionizing radiation. 5. There is a need to educate medical staff and conduct further research on the methods of diagnostic imaging in children.

Оптимизация параметров импульсных РЧ-последовательностей для МРТ-исследований в присутствии магнитных наночастиц

The influence of parameters of various pulsed radio frequency (RF) sequences on the contrast of magnetic resonance (MR) images is investigated. A program for modeling of magnetic resonance imaging (MRI) tomograms and determining the optimal values of pulse RF sequences parameters to achieve the best contrast of MR images has been developed. This program has been tested for MRI studies using negative contrast agents based on magnetic iron oxide nanoparticles and positive contrast agents based on gadolinium. Their influence on MR signal intensity depending on concentration is analyzed. Recommendations on the choice of optimal values of RF sequences parameters for MRI diagnostics using contrasting agents are developed.