Magnetic resonance imaging in the diagnosis of knee joint sarcomas

The purpose of the investigation was to study the potentialities of magnetic resonance imaging (MRI) in the diagnosis of knee joint sarcomas. The paper presents the results of examining 13 patients of different age, shows the potentialities of the technique in the identification of knee joint sarcomas, and describes the MRI semiotics of sarcomas in both the routine study and that using contrast enhancement in lesions of bone and soft tissue elements in the presence of regional metastases.     

Magnetic resonance imaging of arterial thrombi and its possible correlation to fibrinolytic treament

For 13 patients with subacute and 4 patients with chronic occlusion, magnetic resonance imaging (MRI) of occlusive arterial thrombi in the superficial femoral artery were performed in vivo. The patients with subacute occlusion were treated with catheter-directed thrombolysis. The frequency of MR signal intensity and its distribution in thrombi were studied for 11 successfully and 2 unsuccessfully treated patients and patients with chronic occlusion. Intra-arterial thrombi were MRI inhomogenous in all of the patients, but the MR signals from lysable and chronic thrombi were significantly different than those from nonlysable ones. The MRI of occlusive arterial thrombi is probably usable to predict the therapeutic outcome of thrombolytic treatment.     

In vivo ankle joint kinematics from dynamic magnetic resonance imaging using a registration-based framework

In this paper, we propose a method for non-invasively measuring three-dimensional in vivo kinematics of the ankle joint from a dynamic MRI acquisition of a single range-of-motion cycle. The proposed approach relies on an intensity-based registration method to estimate motion from multi-plane dynamic MRI data. Our approach recovers not only the movement of the skeleton, but also the possibly non-rigid temporal deformation of the joint. First, the rigid motion of each ankle bone is estimated. Second, a four-dimensional (3D+time) high-resolution dynamic MRI sequence is estimated through the use of the log-euclidean framework for the computation of temporal dense deformation fields. This approach has been then applied and evaluated on in vivo dynamic MRI data acquired for a pilot study on six healthy pediatric cohort in order to establish in vivo normative joint biomechanics. Results demonstrate the robustness of the proposed pipeline and very promising high resolution visualization of the ankle joint.     

Magnetic resonance imaging: bioeffects and safety concerns

Magnetic resonance imaging (MRI) is the state-of-the-art noninvasive imaging modality in clinical diagnosis. During MRI examination, the patient is exposed to three different forms of electromagnetic radiation: (i) a static magnetic field, (ii) gradient magnetic fields, and (iii) radiofrequency (RF) fields. Each of these may cause significant adverse bioeffects if applied at sufficiently high exposure levels. This article describes in some detail the areas of health concern for both the patient and the health practitioner with respect to the use of clinical MRI, in addition to describing the potential bioeffects of electromagnetic radiations used in this sophisticated imaging modality.     

Magnetic resonance imaging: present and future applications

Magnetic resonance (MR) imaging has created considerable excitement in the medical community, largely because of its great potential to diagnose and characterize many different disease processes. However, it is becoming increasingly evident that, because MR imaging is similar to computed tomography (CT) scanning in identifying structural disorders and because it is more costly and difficult to use, this highly useful technique must be judged against CT before it can become an accepted investigative tool. At present MR imaging has demonstrated diagnostic superiority over CT in a limited number of important, mostly neurologic, disorders and is complementary to CT in the diagnosis of certain other disorders. For most of the remaining organ systems its usefulness is not clear, but the lack of ionizing radiation and MR''s ability to produce images in any tomographic plane may eventually prove to be advantageous. The potential of MR imaging to display in-vivo spectra, multinuclear images and blood-flow data makes it an exciting investigative technique. At present, however, MR imaging units should be installed only in medical centres equipped with the clinical and basic research facilities that are essential to evaluate the ultimate role of this technique in the care of patients.     

Magnetic resonance tomography of temporomandibular joint

The paper shows the place of magnetic resonance imaging among other radiation diagnostic techniques in detecting abnormal changes in the temporomandibular joint. The authors' own data were based on the results of 315 examinations. The paper describes the technical features of examination of the joint and shows it possible to visualize different anatomic structures on T1-, T2- and Pd-weighted images. It also indicates the diagnostic potentialities of magnetic resonance imaging in identifying abnormal changes in the joint in its diseases and lesions. This has allowed the authors to show what is indicated for magnetic resonance imaging of the temporomandibular joint and that it is necessary to develop an algorithm of radiation diagnosis for patients with different clinical forms of joint diseases.     

Magnetic resonance imaging of glutamate

Glutamate, a major neurotransmitter in the brain, shows a pH- and concentration-dependent chemical exchange saturation transfer effect (GluCEST) between its amine group and bulk water, with potential for in vivo imaging by nuclear magnetic resonance. GluCEST asymmetry is observed ～3 p.p.m. downfield from bulk water. Middle cerebral artery occlusion in the rat brain resulted in an ～100% elevation of GluCEST in the ipsilateral side compared with the contralateral side, predominantly owing to pH changes. In a rat brain tumor model with blood-brain barrier disruption, intravenous glutamate injection resulted in a clear elevation of GluCEST and a similar increase in the proton magnetic resonance spectroscopy signal of glutamate. GluCEST maps from healthy human brain were also obtained. These results demonstrate the feasibility of using GluCEST for mapping relative changes in glutamate concentration, as well as pH, in vivo. Contributions from other brain metabolites to the GluCEST effect are also discussed.     

Magnetic resonance imaging of the vomeronasal organ

The vomeronasal organ of mice and frogs was studied by highspatial resolution magnetic resonance imaging. By this techniquethe presence of material in the vomeronasal lumen can be evidencedin vivo.     

Magnetic resonance imaging stereotaxy: recognition and utilization of the commissures

Magnetic Resonance Imaging (MRI) offers a non-invasive method to visualize the intracerebral structures. Coupled to a compatible stereotactic frame and software, MRI can be used to determine the coordinates of intracranial targets. Coordinates of the anterior commissure, posterior commissure, targets and intercommissural distance were obtained from positive contrast ventriculography and by MRI in 6 patients undergoing stereotactic localization prior to the implantation of stimulating thalamic electrodes for pain control. The correlation of coordinates and measurements obtained with ventriculography and MRI is +/- 1 mm in most measurements, but up to 3 mm in 2 cases. Magnetic resonance stereotaxy allows non-invasive and precise localization of intracerebral targets, but does not yet allow its routine use with confidence. Further understanding of distortion and artifacts and corrections of these is mandatory.     

Age-related changes of the bones of the leg, foot and ankle joint in pole-vaulters

The data on age changes occurring in the height of the articular cleft of the talocrural joint, in morphological components of the diaphysis of the crus and foot bones have been presented in pole-jumpers and in non-sportsmen at the age of 13-21 years. Roentgenological, roentgenogrammetric and x-ray densitometric methods have been used. At the age of 14-15 years the greatest changes in the talocrural joint, crus and foot bones are noted.     

Magnetic resonance imaging in personalized medicine

正Continued biomedical advances and increased demands on quality health care have led to a new era of personalized medicine—a concept of medicine that uses specific information to an individual to help diagnose disease,plan treatment,assess treatment efficacy,and/or predict prognosis.This concept has evolved from the idea ofpatient-centered care,which intends to shift the focus of health care from diseases to patients(Abujudeh et al.,2016).Medical imaging is essential in the practice of modern medicine,and its role in personalized medicine has never been greater.In particular,magnetic resonance(MR)     

Magnetic resonance imaging and spectroscopy of prostate cancer

Magnetic resonance imaging may improve the staging of prostate cancer compared with clinical evaluation alone, computerized tomography, or transrectal ultrasound, and it allows simultaneous and detailed evaluation of prostatic, periprostatic, and pelvic anatomy. Endorectal magnetic resonance imaging and magnetic resonance spectroscopic imaging (endoMRI/MRSI) allow better visualization of the zonal anatomy of the prostate and better delineation of tumor location, volume, and extent (stage). Metabolic criteria used to identify and localize prostate cancer with endoMRI/MRSI have been standardized, thus improving the accuracy of the examination and limiting interobserver variations in interpretation. Evidence is now emerging that endoMRI/MRSI may also be helpful in assessing response to prostate cancer treatment, most commonly with radiation and/or androgen-deprivation therapy.