MRI Technology Research Articles

Segmentasi Citra Mri Menggunakan Deteksi Tepi Untuk Identifikasi Kanker Payudara

One type of cancer that is capable identified using MRI technology is breast cancer. Breast cancer is still the leading cause of death world. therefore early detection of this disease is needed. In identifying breast cancer, a doctor or radiologist analyzing the results of magnetic resonance image that is stored in the format of the Digital Imaging Communication In Medicine (DICOM). It takes skill and experience sufficient for diagnosis is appropriate, andaccurate, so it is necessary to create a digital image processing applications by utilizing the process of object segmentation and edge detection to assist the physician or radiologist in identifying breast cancer. MRI image segmentation using edge detection to identification of breast cancer using a method stages gryascale change the image format, then the binary image thresholding and edge detection process using the latest Robert operator. Of the20 tested the input image to produce images with the appearance of the boundary line of each region or object that is visible and there are no edges are cut off, with the average computation time less than one minute.

Identification and evaluation of clinically significant prostate cancer: a step towards personalized diagnosis.

Prostate cancer (PCa) diagnostics are evolving rapidly. The quest to differentiate 'clinically significant' from 'clinically insignificant' disease has gathered momentum, leading to substantial change in traditional diagnostic approaches. Herein, we review the relevant information on currently available biomarkers and assess their ability to help physicians and patients in making a shared and personalized decision based on their individual risk of harbouring clinically significant disease. Serum, urine, tissue and imaging biomarkers have been evaluated to improve the identification of clinically significant disease, and this international effort has yielded promising, but not always consistent results. Changes in MRI technology have realized a quantum change, and this facility is now becoming more widely incorporated into diagnostic and disease risk-stratification protocols. However, standardization and further validation is required. Acceptance and widespread adoption of serum, urine and genetic markers is awaited, but novel and promising techniques alone and in combination have emerged. With validation and further focus, these may be adopted more widely.

MRI investigation of the ear canal deformation due to earplugs: A first step toward understanding wearing comfort

The effective protection of earplugs is related to the acoustical attenuation but also to the comfort they provide. Earplugs are acoustic seals used to reduce sound transmission in the ear canal. A perfect contact between ear canal and earplug should ideally avoid acoustic leaks leading to under-protection. Practically, this acoustic seal is achieved applying a greater or lesser deformation on the ear canal walls which depends on the earplug insertion and type. However, a too large deformation can modify the acoustic attenuation and cause physical pain due to mechanical pressure exerted onto ear canal walls leading the wearer to take earplugs off and reducing their protection. This study aims at investigating the ear canal deformation of one human subject due to insertion of various earplugs known for providing different levels of protection and different levels of comfort. The shape of the open and occluded right and left ear canals of the subject is measured using MRI technology. The deformation along the ear canal is estimated using an imaging registration method. The results show large displacements at the ear canal entrance for all earplugs and non negligible displacements after the first bend of the ear canal for some of them.

MRI技術の最前線 : 拡散MRIとその脳機能イメージング・白質病変解析への応用

MRI技術の最前線 : 拡散MRIとその脳機能イメージング・白質病変解析への応用

Quantifying the dynamic density driven convection in high permeability packed beds

The density driven convection phenomenon is expected to have a significant and positive role in CO2 geological storage capacity and safety. The onset and development of density-driven convective on the core scale is critical to understand the mass transfer mechanism. In this paper, laboratory experiments were conducted to investigate the density-driven convective in a vertical tube. The deuterium oxide (D2O)/manganese chloride (MnCl2) water solution in water or brine were as an analog for CO2-rich brine in original brine. Experiments are repeated with variations in permeability to vary the characteristic Rayleigh number. Based on the MRI technology, the intensity images showed the interface clearly, reflecting the transition from diffusion to convective. With the echo-multi-slice pulse sequence method, the intensity images can be obtained as 2min 8s. For the denser fluid pairs, fingers appeared, propagated, coalesced and multi-fingers formed. The finger growth rate of the convective was visualized as three distinct periods: rising, stable and declining. Detailed information regarding the wave number, wave length, onset time and mixing time as functions of Rayleigh number are developed.

The utilization of magnetic resonance imaging in the operating room

Online image guidance in the operating room using ultrasound imaging led to the resurgence of prostate brachytherapy in the 1980s. Here we describe the evolution of integrating MRI technology in the brachytherapy suite or operating room. Given the complexity, cost, and inherent safety issues associated with MRI system integration, first steps focused on the computational integration of images rather than systems. This approach has broad appeal given minimal infrastructure costs and efficiencies comparable with standard care workflows. However, many concerns remain regarding accuracy of registration through the course of a brachytherapy procedure. In selected academic institutions, MRI systems have been integrated in or near the brachytherapy suite in varied configurations to improve the precision and quality of treatments. Navigation toolsets specifically adapted to prostate brachytherapy are in development and are reviewed.

Identification of the specific topographic features of the neck vessels for the prevention of bleedings during tonsillectomy

The objective of the present work was to study syntopy of the large neck vessels in relation to the capsule of palatine tonsils with the use of the MRI technology. A total of 109 patients (218 palatine tonsils) presenting with chronic tonsillitis were available for the examination including 64 women and 45 men at the age varying from 15 to 54 years. All of them underwent MRI-guided vascular visualization in the paratonsillar region together with the measurements of the vessels extending to the capsule of the palatine tonsils at the level of the upper and lower poles, and also close to the mid-third of each palatine tonsil. The distance from the external carotid artery to the upper and lower poles of the palatine tonsils was found to be 17.1±1.01 mm and 10.3±0.18 mm respectively and in the mid-third the palatine tonsil 10.7±0.12 mm; the distance from the internal carotid artery to the upper and low poles of the palatine tonsil amounted to 14.5±0.84 mm and 16.8±0.77 mm respectively while that to the mid-third of the palatine tonsil was 15.3±0.07 mm. The branches of the external carotid artery feeding the palatine tonsils are the most frequent sources of bleedings; the following measurements were obtained: the maxillary artery 16.4±0.43 mm (17.4%) - the upper pole 9.6±0.02 mm (46.2%), the mid-third of the palatine tonsil 18.5±0.74 mm (29.5%) - the lower pole; the lingual artery 4.7±0.02 mm (6.8%) - the mid-third of the palatine tonsil, 6.2±0.82 mm (56.8%) - the lower pole; facial artery: 4.2±0.01 mm (0.76%) - the mid-third of the palatine tonsil; the occipital artery 25.6±0.12 mm (19%) - the upper pole; 14.8±0.11 mm (18.9%) - the mid-third of the palatine tonsil 9.56±0.12 mm (3.8%) - the lower pole; the tonsillar artery 1.88±0.01 mm (9.8%) - the upper pole; 2.51±0.01 mm (23%) - the mid-third of the palatine tonsil; 2.12±0.01 mm (11%) - the lower pole. The distance from the internal jugular vein to the capsule of the palatine tonsils in the region of the upper pole of the palatine tonsil was 28.3±1.01 mm, in the lower pole region 26.6±1.54 mm, and in the region of the mid-third of the palatine tonsil 22.7±1.24 mm. It is concluded that the results of the present study may be useful for the planning of the surgical strategy for the treatment of the patients presenting with chronic tonsillitis and for the prevention of hemorrhagic complications of tonsillectomy.

The Magnetic Field Produced by the Heart and Its Influence on MRI

Background. Action currents in the heart produce a magnetic field, which could provide a way to detect the propagation of electrical activity through cardiac tissue using magnetic resonance imaging. However, the magnetic field produced by current in the heart is small. The key question addressed in this study is are cardiac biomagnetic fields large enough to be detectable by MRI? Results. A spherical model is used to calculate the magnetic field inside the heart, which has a magnitude of about 14 nT. This field implies a phase shift in the MRI signal of about 0.2°. Conclusion. Phase shifts associated with cardiac action currents will be difficult to detect using current MRI technology but may be possible if motion artifacts and other physiological noise can be suppressed.

A PERMANENT NEUROSURGICAL CHALLENGE: LOW GRADE GLIOMAS

Introduction. The utilization of Magnetic Resonance Spectroscopy (MRS) brings an important piece of information to an overall MR study, thus aiding the physician in making an accurate assumption regarding the histological grade of a tumor. The purpose of this study is to verify the reliability of MRS in correctly diagnosing both the nature of tumors and their grade. Material and methods. This is an observational study that was conducted from January 2011 to June 2016 on 49 patients confirmed to be low-grade gliomas (LGG) by pathological examination, who were admitted in our Neurosurgery Department in this period. Both retrospective and prospective data were collected. Inclusion criteria comprise unique tumoral lesion at the moment of diagnosis, follow-up for at least one year. Exclusion criteria included: other types of tumors with any location, patient refusal to undergo histopathological examination of the resected tissue, uncompliant and non-collaborating patients. Of all patients, 22 were subjected to an MRS study which suggested the presence of a low-grade glioma subsequently confirmed by the pathological examination. Results. MRS has been shown to provide accurate non-invasive diagnosis of LGG’s, by analyzing the concentration of metabolites inside the lesions which tend to be specific for these tumours: relatively elevated levels of N-acetylaspartate and creatine with reduced levels in the concentration of choline and absent lipids and lactate. It has also been observed that pre-operative MRS assists the physician in selecting the optimal place for biopsy, so that the pathological examination provides conclusive results. Conclusions. With the increased availability of MRI technology, MRS comes as a milestone in the advancement of more accurate and patient-friendly methods of diagnostic for pathologies as LGG’s which constitute a permanent challenge for neurosurgeons. The results of this study underlines the importance of MRS as a method for follow up patients with LGG, but cannot replace the need for obtaining bioptic tissue for pathological examination, especially after the new grading system of WHO, which was published in June 2016. This new grading system takes into account the molecular biology in predicting the natural history of cerebral tumours.

Dyslexia: 10 Strategies

Dyslexia once thought of as a hidden learning difficulty is now exposed, due to MRI technology, as a specific learning disability. Dyslexia has a neurological basis that transverses all languages and cultures. Early identification of possible at risk students ought to occur so that immediate intervention strategies can be implemented. Schools also need to ensure that reading instruction includes all elements of ‘The Big 6 of Reading’ and these elements are taught using an explicit direct multi sensory methodology. As dyslexia has an impact on all areas of the student’s education; early intervention including adjustment to student tasks and assessments needs to occur to ensure that the student develops an understanding of dyslexia; their personal strengths and weaknesses; and strategies for successful achievement, thus enabling the student to build a positive self-esteem.

A multimodality imaging model to track viable breast cancer cells from single arrest to metastasis in the mouse brain.

Cellular MRI involves sensitive visualization of iron-labeled cells in vivo but cannot differentiate between dead and viable cells. Bioluminescence imaging (BLI) measures cellular viability, and thus we explored combining these tools to provide a more holistic view of metastatic cancer cell fate in mice. Human breast carcinoma cells stably expressing Firefly luciferase were loaded with iron particles, injected into the left ventricle, and BLI and MRI were performed on days 0, 8, 21 and 28. The number of brain MR signal voids (i.e., iron-loaded cells) on day 0 significantly correlated with BLI signal. Both BLI and MRI signals decreased from day 0 to day 8, indicating a loss of viable cells rather than a loss of iron label. Total brain MR tumour volume on day 28 also correlated with BLI signal. Overall, BLI complemented our sensitive cellular MRI technologies well, allowing us for the first time to screen animals for successful injections, and, in addition to MR measures of cell arrest and tumor burden, provided longitudinal measures of cancer cell viability in individual animals. We predict this novel multimodality molecular imaging framework will be useful for evaluating the efficacy of emerging anti-cancer drugs at different stages of the metastatic cascade.

Introduction to Magnetic Resonance Imaging for Neurologists

In neuroradiology, highly sophisticated methods such as MRI are implemented to investigate different entities of the central nervous system and to acquire miscellaneous images where tissues display varying degrees of characteristic signal intensity or brightness. Compared to x-ray, CT, and ultrasound, MRI produces clearer images of tissues, body fluids, and fat. The basics of MRI may be unknown to neurologists; this article introduces MRI physics, techniques, and interpretation guidelines. This article discusses the basics of MRI to provide clinicians with the scientific underpinning of MRI technology and to help them better understand image features and improve their diagnosis and differential diagnosis by combining MRI characteristics with their knowledge of pathology and neurology. This article will help neurologists deepen their knowledge and understanding of MRI by introducing the basics of MRI physics, technology, image acquisition, protocols, and image interpretation.

Emulsion Stability Modulates Gastric Secretion and Its Mixing with Emulsified Fat in Healthy Adults in a Randomized Magnetic Resonance Imaging Study

Background: Oil-in-water emulsions have recently become of interest to nutritional sciences because of their ability to influence gastrointestinal digestive processes and ultimately benefit human health. MRI offers the potential to noninvasively characterize the interaction between emulsified lipids and gastric secretion within the stomach.Objectives: We determined noninvasively how emulsion stability modulates volumes of fat and secretion, layering of fat, and the mixing of emulsified fat with secretion within the stomach. This required the development of MRI technology for quantifying fat and secretion concentrations inside the stomach.Methods: Twenty-one healthy adults [13 men, mean ± SD age: 22.5 ± 2.5 y, mean ± SD body mass index (in kg/m2): 22.7 ± 1.8] were analyzed in a single-blind, randomized, parallel design. MRI was used to acquire the distributions of fat and secretion in the stomach after ingestion of 2 emulsions: a stable emulsion (E1) or an unstable emulsion (E4) with 20% fat fraction and ∼0.3 mm droplet sizes. Layer, volume, and mixing variables were fitted to the data and compared between the 2 emulsions.Results: The intragastric mixing between fat and secretion was better with the E4 than the E1 [increase in content heterogeneity of 17.1% (95% CI: 12.3%, 21.9%)]. The E4 demonstrated a linear relation [slope 1.57 (95% CI: 0.86, 2.29)] between the degree of layering and mixing. In contrast, no such relation was detected for the E1. Accumulated secretion volume in the stomach was lower with the E4 [decrease in volume variable ks of 2.3 (95% CI: −3.9, −0.7)] and correlated with the degree of layering (r = 0.62, P < 0.001).Conclusions: In healthy adults, intragastric fat layering was influenced mainly by the degree of intragastric mixing, rather than the overall dominance of secretion. The E1 triggered a higher accumulation of gastric secretion, which in turn facilitated homogenization of intragastric content in comparison with its unstable counterpart. This trial was registered at clinicaltrials.gov as NCT02602158.

Fast-Field Cycling MRI: A new tool for enhanced diagnosis

Fast Field-Cycling MRI (FFC MRI) is a major shift in MRI technology. It aims to explore how relaxation rates change with the magnetic field strength, an idea that has been successfully exploited in NMR for more than half a century and which is known to provide unique structural information on materials, non-invasively. Scaling up FFC NMR to whole-body MRI systems is a difficult technical challenge that has maintained a lock on this area of research for many years. Our research group has successfully lifted this lock and developed two whole-body FFC MRI scanners: one with a field range of 0.1 mT to 59 mT that has been used in clinical trials for several years and the other with a range of 20 uT to 0.2 T still under development. Our pilot studies, which use both FFC MRI and FFC NMR, have discovered new biomarkers in a range of diseases such as osteoarthritis, breast carcinoma, musculoskeletal sarcoma, obesity, liver fibrosis, thrombosis and others. These FFC MRI biomarkers can differentiate tissues that appear similar on conventional MRI devices thanks, in part, to the greater endogenous contrast present at lower magnetic fields but also due to patterns that emerge from the overall relaxation dispersion curves of these tissues. The latter provides unique insight into the structure of materials and is, we believe, a promising tool to characterise tissue remodelling. This presentation will focus on FFC MRI technology, how it differs from conventional MRI and the results obtained so far from our pilot studies. Fast Field-Cycling MRI (FFC MRI) is a major shift in MRI technology. It aims to explore how relaxation rates change with the magnetic field strength, an idea that has been successfully exploited in NMR for more than half a century and which is known to provide unique structural information on materials, non-invasively. Scaling up FFC NMR to whole-body MRI systems is a difficult technical challenge that has maintained a lock on this area of research for many years. Our research group has successfully lifted this lock and developed two whole-body FFC MRI scanners: one with a field range of 0.1 mT to 59 mT that has been used in clinical trials for several years and the other with a range of 20 uT to 0.2 T still under development. Our pilot studies, which use both FFC MRI and FFC NMR, have discovered new biomarkers in a range of diseases such as osteoarthritis, breast carcinoma, musculoskeletal sarcoma, obesity, liver fibrosis, thrombosis and others. These FFC MRI biomarkers can differentiate tissues that appear similar on conventional MRI devices thanks, in part, to the greater endogenous contrast present at lower magnetic fields but also due to patterns that emerge from the overall relaxation dispersion curves of these tissues. The latter provides unique insight into the structure of materials and is, we believe, a promising tool to characterise tissue remodelling. This presentation will focus on FFC MRI technology, how it differs from conventional MRI and the results obtained so far from our pilot studies.

Basic MRI physics for radiotherapy physicists

CT has long been the modality of choice for radiotherapy treatment planning, because of its inherent lack of spatial distortion and its natural ability to provide electron-density information about tissues, directly feeding in to dose calculations. Nevertheless, MRI offers much better soft-tissue contrast than CT, with the added benefit of zero radiation dose. Advances in MRI technology have improved its geometric accuracy, while image segmentation allows dose-related parameters to be inferred, making MRI a viable option for radiotherapy planning. In MRI-guided radiotherapy, MR images are used to delineate tumour boundaries and guide the radiation distribution in real time. MRI uses signals generated by nuclear magnetic resonance (NMR) of magnetic hydrogen nuclei (protons). The frequency of the signal depends on the strength of the magnetic field, typically 1.5 tesla giving an NMR frequency of 64 MHz. Spatial information is obtained by magnetic field gradients, which alter the local magnetic field (and hence the resonant frequency) as a function of position; analysis of the frequency and phase of the measured NMR signals allows images to be produced in 2- or 3-dimensions. The geometric accuracy of the images is crucial to MR-based treatment planning, and depends on the homogeneity of the main magnetic field and the linearity and homogeneity of the magnetic field gradients. A plethora of MRI pulse sequences exist, which can be optimised to improve the results of image segmentation for dose calculations. This presentation will cover MRI concepts and how they impact on MR-based treatment-planning and on MR-guided therapy.

Study on compressed sensing reconstruction algorithm of medical image based on curvelet transform of image block

Traditional MRI technology may easily generate artifact due to slow imaging speed, therefore, MRI has low imagining quality and over-long sampling duration. Since wavelet transform cannot achieve the best approximation, image block theory is introduced in compressed sensing image reconstruction. In combination of the advantage of curvelet transform – it is suitable for expressing edge detail information and curve information, curvelet transform is utilized to conduct sparse representation of MRI image and proposed compressed sensing reconstruction algorithm of MRI image based on curvelet transform of image block. Signal to Noise Ratio (SNR), Relative L2 norm error (RLNE) and matching degree served as the evaluation indexes, and 4 groups of experiments about the influence of noise-free image, noised image, different sampling frequencies and different regularization parameters on the quality of reconstructed image were done. The results show that during image reconstruction, the algorithm proposed in this paper is superior to SIDCT and PBDCT in terms of three evaluation indexes. Besides, the algorithm owns strong ability to resist noise and good effects on keeping image detail and edge.

Estimation of Tumor Interstitial Fluid Pressure (TIFP) Noninvasively.

Tumor interstitial fluid pressure (TIFP), is a physiological parameter with demonstrated predictive value for a tumor’s aggressiveness, drug delivery, as well as response to treatments such as radiotherapy and chemotherapy. Despite its utility, measurement of TIFP has been limited by the need for invasive procedures. In this work, the theoretical basis for approaching the absolute value of TIFP and the experimental method for noninvasively measuring TIFP are presented. Given specific boundary and continuity conditions, we convert theoretical variables into measurable variables by applying MRI technology. The work shows that TIFP in the central region of the tumor can be estimated by an analysis of the variation of tissue fluid motion in the tumor rim and surrounding tissue. It is determined from three noninvasive measurable parameters: i) an estimate of the velocity of the tumor interstitial fluid at the tumor surface, which is maximal, ii) a measurement of the distance from the tumor surface to where the tumor exudates are absorbed (or normalized), and iii) an estimate of the hydraulic conductivity of the interstitium through which the tumor exudate travels. We experimentally show that the fluid flow within the tumor rim is not uniform, even for a round shaped tumor, and demonstrate the procedures for the noninvasive measurement of TIFP.

Giant Cell Arteritis Presenting with Bilateral Subdural Haematomas of Arterial Origin.

Giant cell arteritis or temporal arteritis is an inflammatory condition affecting medium to large sized vessels, particularly the cranial arteries. A 76-year-old man with no significant past medical history presented to the emergency department with a 3-week history of diffuse headaches associated with fever, loss of appetite, weight loss and general malaise. A CT scan of the brain showed bilateral shallow chronic low density subdural haematomas. A complete laboratory panel was unremarkable except for a raised erythrocyte sedimentation rate and elevated C-reactive protein. A transthoracic echocardiogram and CT scan of the body were unremarkable. MRI of the brain confirmed bilateral old subdural collections and showed marked vessel wall enhancement in the frontal branches of the left superficial temporal artery. A left temporal artery biopsy confirmed giant cell temporal arteritis. We speculate that a vasculitic process in the small subdural arteries may have contributed to our patient’s spontaneous subdural haematomas.LEARNING POINTSA contrast-enhanced T1 axial fat-suppressed MRI of the brain is a non-invasive modality of diagnostic value in giant cell arteritis (GCA); increased access to high resolution MRI technology may reduce the requirement for invasive temporal artery biopsy in the future.Subdural hematomas may be of arterial origin; GCA has been reported in association with subdural hematomas but causation is not proven.GCA must be suspected in patients presenting with headaches and raised inflammatory markers even in the absence of classic features or dual pathology as failure to recognize and treat promptly could lead to permanent visual loss.

Anesthetic management and human factors in the intraoperative MRI environment.

The use of intraoperative MRI technology during neurosurgery has become increasingly more common over the past several years. These surgical procedures require a specialized operating room designed to accommodate an MRI machine, as well as MRI-compatible anesthesia equipment and monitors. The MRI environment also poses unique risks and challenges to both patients and medical staff. General anesthesia in the MRI operating room suite poses several challenges not routinely experienced in a conventional operating room suite, and anesthesia providers delivering care in these suites must complete specialized training and screening. The presence of a magnetic field, as well as reduced access to the patient during the MRI scan, require high levels of vigilance. The use of checklists and teamwork training can maximize both patient and provider safety in the intraoperative MRI environment.

Cerebral functional deficits in patients with ankylosing spondylitis- an fMRI study.

Neurological impairment plays an important role in the development of Ankylosing spondylitis (AS). Early diagnosis and detection of it may stop the progress of neurological complications and improve the quality of patients' lives greatly. Somatosensory evoked potential (SSEP) and magnetic motor evoked potentials (MEP) have been proved useful to detect neurological impairments of AS. This study aimed to investigate the cerebral function deficits of AS using functional MRI technology. Twenty seven patients with AS and 28 control subjects were included in this study. All of them underwent structural MRI and resting state-functional MRI (rs-fMRI) scanning. Comparisons of amplitude of low frequency fluctuations (ALFF) of rs-fMRI signals between AS patients and normal controls were performed using two sample t-tests. To examine functional connectivity within the groups, one-sample t tests were performed on the individual z-value maps. The z values were compared between the two groups using two-sample t test. Partial correlations between rs-fMRI measures (ALFF and functional connectivity) of the brain regions which showed group difference and clinical results including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score, the serum high-sensitivity C-reactive protein (hsCRP), and the erythrocyte sedimentation rate (ESR) were analyzed for AS patients. Compared with normal controls, the AS patients exhibited significant lower ALFF in the left medial frontal gyrus, the right precentral gyrus and the right posterior cingulate, while higher ALFF in the left cerebellum anterior lobe, the left middle temporal gyrus, the left superior occipital gyrus, the left postcentral gyrus and the right precuneus. AS patients showed widespread brain connectivity alterations. Functional connectivity strength of the left precuneus and the left middle temporal gyrus were closely correlated with the the BASDAI scores, ESR and hsCRP in AS patients. Our results enhance the understanding of the pathomechanism of AS and suggest that Rs-fMRI may be a helpful tool in the clinical detection and evaluation of neurological impairment in AS.