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Sample records for magnetics resonance diagnosis

  1. Magnetic resonance imaging in the diagnosis of spinal cord diseases.

    PubMed Central

    Aichner, F; Poewe, W; Rogalsky, W; Wallnöfer, K; Willeit, J; Gerstenbrand, F

    1985-01-01

    Experience with magnetic resonance imaging in 22 patients with diseases of the spinal cord is reported. Important additional diagnostic information as compared to conventional neuroradiological techniques (myelography, spinal CT) was gained especially in cases of hydrosyringomyelia, intraspinal tumour and multiple sclerosis. It is suggested that magnetic resonance imaging may become the method of choice in the diagnosis of structural spinal cord diseases. Images PMID:3936900

  2. Correct diagnosis for plunging ranula by magnetic resonance imaging.

    PubMed

    Li, Jian; Li, Jun

    2014-06-01

    Plunging ranulas most commonly occupy the submandibular triangle and misdiagnosis inevitably leads to incorrect treatment. Three cases of plunging ranula are reported. The correct diagnosis resulted from the characteristic signs of magnetic resonance imaging (MRI). Treatment consisted of the total removal of the sublingual gland and evacuation of cystic contents by the intraoral approach. The cyst gradually regressed and disappeared within two months after surgery as confirmed by ultrasonography. All three cases have not experienced recurrence in the follow-up period. MRI is a valuable method to correctly diagnosis plunging ranula. Total removal of the sublingual gland is the most reliable method to treat plunging ranula.

  3. Magnetic resonance imaging for the diagnosis of Parkinson's disease.

    PubMed

    Heim, Beatrice; Krismer, Florian; De Marzi, Roberto; Seppi, Klaus

    2017-04-04

    The differential diagnosis of parkinsonian syndromes is considered one of the most challenging in neurology and error rates in the clinical diagnosis can be high even at specialized centres. Despite several limitations, magnetic resonance imaging (MRI) has undoubtedly enhanced the diagnostic accuracy in the differential diagnosis of neurodegenerative parkinsonism over the last three decades. This review aims to summarize research findings regarding the value of the different MRI techniques, including advanced sequences at high- and ultra-high-field MRI and modern image analysis algorithms, in the diagnostic work-up of Parkinson's disease. This includes not only the exclusion of alternative diagnoses for Parkinson's disease such as symptomatic parkinsonism and atypical parkinsonism, but also the diagnosis of early, new onset, and even prodromal Parkinson's disease.

  4. Value of Magnetic Resonance Imaging for Diagnosis of Dentigerous Cyst

    PubMed Central

    Galvão, Neiandro dos Santos; Ferreira, Thásia Luiz Dias; Lopes, Sérgio Lúcio Pereira de Castro

    2016-01-01

    Odontogenic cysts have a high prevalence in the dental clinic population, with dentigerous cyst being one of the most frequent ones and whose aetiology involves accumulation of fluid between the reduced enamel epithelium and the crown of an unerupted tooth. In the diagnostic process of these lesions, one should consider complementary imaging exams such as conventional radiography and computed tomography, which are commonly used for providing anatomical information on the tissues compromised by the lesion, but not on the nature of it. Magnetic resonance imaging (MRI) scans are noninvasive modalities which, due to their unique acquisition characteristics, can provide distinct information on the nature of the lesion. This study reports on a case of dentigerous cyst in the mandible of a 9-year-old patient, documented by means of different imaging modalities. MRI played an important role in both diagnosis of the lesion and differential diagnosis between neoplastic lesions presenting similar imagenological behaviour under other techniques of radiography. PMID:27795861

  5. Magnetic resonance imaging markers for early diagnosis of Parkinson's disease☆

    PubMed Central

    Marino, Silvia; Ciurleo, Rosella; Di Lorenzo, Giuseppe; Barresi, Marina; De Salvo, Simona; Giacoppo, Sabrina; Bramanti, Alessia; Lanzafame, Pietro; Bramanti, Placido

    2012-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by selective and progressive degeneration, as well as loss of dopaminergic neurons in the substantia nigra. In PD, approximately 60-70% of nigrostriatal neurons are degenerated and 80% of content of the striatal dopamine is reduced before the diagnosis can be established according to widely accepted clinical diagnostic criteria. This condition describes a stage of disease called “prodromal”, where non-motor symptoms, such as olfactory dysfunction, constipation, rapid eye movement behaviour disorder, depression, precede motor sign of PD. Detection of prodromal phase of PD is becoming an important goal for determining the prognosis and choosing a suitable treatment strategy. In this review, we present some non-invasive instrumental approaches that could be useful to identify patients in the prodromal phase of PD or in an early clinical phase, when the first motor symptoms begin to be apparent. Conventional magnetic resonance imaging (MRI) and advanced MRI techniques, such as magnetic resonance spectroscopy imaging, diffusion-weighted and diffusion tensor imaging and functional MRI, are useful to differentiate early PD with initial motor symptoms from atypical parkinsonian disorders, thus, making easier early diagnosis. Functional MRI and diffusion tensor imaging techniques can show abnormalities in the olfactory system in prodromal PD. PMID:25745453

  6. Magnetic resonance imaging differential diagnosis of brainstem lesions in children

    PubMed Central

    Quattrocchi, Carlo Cosimo; Errante, Yuri; Rossi Espagnet, Maria Camilla; Galassi, Stefania; Della Sala, Sabino Walter; Bernardi, Bruno; Fariello, Giuseppe; Longo, Daniela

    2016-01-01

    Differential diagnosis of brainstem lesions, either isolated or in association with cerebellar and supra-tentorial lesions, can be challenging. Knowledge of the structural organization is crucial for the differential diagnosis and establishment of prognosis of pathologies with involvement of the brainstem. Familiarity with the location of the lesions in the brainstem is essential, especially in the pediatric population. Magnetic resonance imaging (MRI) is the most sensitive and specific imaging technique for diagnosing disorders of the posterior fossa and, particularly, the brainstem. High magnetic static field MRI allows detailed visualization of the morphology, signal intensity and metabolic content of the brainstem nuclei, together with visualization of the normal development and myelination. In this pictorial essay we review the brainstem pathology in pediatric patients and consider the MR imaging patterns that may help the radiologist to differentiate among vascular, toxico-metabolic, infective-inflammatory, degenerative and neoplastic processes. Helpful MR tips can guide the differential diagnosis: These include the location and morphology of lesions, the brainstem vascularization territories, gray and white matter distribution and tissue selective vulnerability. PMID:26834941

  7. Magnetic resonance imaging diagnosis of disseminated necrotizing leukoencephalopathy

    SciTech Connect

    Atlas, S.W.; Grossman, R.I.; Packer, R.J.; Goldberg, H.I.; Hackney, D.B.; Zimmerman, R.A.; Bilaniuk, L.T.

    1987-01-01

    Disseminated necrotizing leukoencephalopathy is a rare syndrome of progressive neurologic deterioration seen most often in patients who have received central nervous system irradiation combined with intrathecal or systemic chemotherapy in the treatment or prophylaxis of various malignancies. Magnetic resonance imaging was more sensitive than computed tomography in detecting white matter abnormalities in the case of disseminated necrotizing leukoencephalopathy reported here. Magnetic resonance imaging may be useful in diagnosing incipient white matter changes in disseminated necrotizing leukoencephalopathy, thus permitting early, appropriate therapeutic modifications.

  8. [Diagnosis. Radiological study. Ultrasound, computed tomography and magnetic resonance imaging].

    PubMed

    Gallo Vallejo, Francisco Javier; Giner Ruiz, Vicente

    2014-01-01

    Because of its low cost, availability in primary care and ease of interpretation, simple X-ray should be the first-line imaging technique used by family physicians for the diagnosis and/or follow-up of patients with osteoarthritis. Nevertheless, this technique should only be used if there are sound indications and if the results will influence decision-making. Despite the increase of indications in patients with rheumatological disease, the role of ultrasound in patients with osteoarthritis continues to be limited. Computed tomography (CT) is of some -although limited- use in osteoarthritis, especially in the study of complex joints (such as the sacroiliac joint and facet joints). Magnetic resonance imaging (MRI) has represented a major advance in the evaluation of joint cartilage and subchondral bone in patients with osteoarthritis but, because of its high cost and diagnostic-prognostic yield, this technique should only be used in highly selected patients. The indications for ultrasound, CT and MRI in patients with osteoarthritis continue to be limited in primary care and often coincide with situations in which the patient may require hospital referral. Patient safety should be bourne in mind. Patients should be protected from excessive ionizing radiation due to unnecessary repeat X-rays or inadequate views or to requests for tests such as CT, when not indicated.

  9. [Modern radiologic imaging in the diagnosis of abdominal diseases. Magnetic resonance imaging and spectroscopy].

    PubMed

    Fuchs, W A

    1989-04-01

    The diagnostic value of magnet resonance imaging for the diagnosis of pathological abdominal conditions has been limited sofar because of artefacts due to movement susceptibility. The current indications comprise: liver: differential diagnosis of metastases, cysts and hemangiomas, identification of small metastases, demonstration of malignant vascular invasion, evaluation of hemochromatosis; kidneys: evaluation of transplant rejection, analysis of complex cysts, demonstration of malignant tumoral invasion. The application of magnetic resonance will be greatly extended by the introduction of rapid image sequences and the application of specific contrast media.

  10. Diagnosis of neonatal neuroblastoma with postmortem magnetic resonance imaging.

    PubMed

    Davis, James; Novotny, Nathan; Macknis, Jacqueline; Alpay-Savasan, Zeynep; Goncalves, Luis F

    2017-03-01

    Postmortem magnetic resonance imaging (MRI) is emerging as a valuable tool to accompany traditional autopsy and has potential for use in cases when traditional autopsy is not possible. This case report will review the use of postmortem MRI with limited tissue sampling to differentiate between metastatic neuroblastoma and hepatoblastoma which could not be clearly differentiated with prenatal ultrasound, prenatal MRI, or emergent postnatal ultrasound. The mother presented to our institution at 27 weeks gestation after an obstetric ultrasound at her obstetrician's office identified a large abdominal mass. Fetal ultrasonography and MRI confirmed the mass but were unable to differentiate between neuroblastoma and multifocal hepatoblastoma. The baby was delivered by cesarean section after nonreassuring heart tones led to an emergent cesarean section. The baby underwent decompressive laparotomy to relieve an abdominal compartment syndrome; however, the family eventually decided to withdraw life support. At this time, we performed a whole body postmortem MRI which further characterized the mass as an adrenal neuroblastoma which was confirmed with limited tissue sampling. Postmortem MRI was especially helpful in this case, as the patient's family declined traditional autopsy.

  11. [The use of magnetic resonance imaging in the diagnosis of plantar fibromatosis: a case report].

    PubMed

    Halefoğlu, Ahmet Mesrur

    2005-01-01

    Plantar fibromatosis is a benign but infiltrative neoplasm, presenting as a slow-growing nodular thickening most often within the central band of the plantar aponeurosis. In this case report, we presented a 43-year-old male patient who had a tender nodule in the sole of the right foot for two years. On magnetic resonance images, the location and signal intensity characteristics of the lesion were suggestive of plantar fibromatosis, which was histologically confirmed following an incisional biopsy. Magnetic resonance imaging is a noninvasive method for confirmation of the clinical diagnosis of plantar fibromatosis and also has an important role in planning surgical treatment by delineating the extent of the lesion.

  12. Proton magnetic resonance spectroscopy for the diagnosis and management of cerebral disorders.

    PubMed

    Rudkin, T M; Arnold, D L

    1999-08-01

    The use of magnetism in medicine has a long and colorful history since its legendary discovery in the Western world by the shepherd Magnes. More recent use of magnetism has centered on nuclear magnetic resonance. Magnetic resonance spectroscopy (MRS) provides chemical information on tissue metabolites. Both hydrogen 1 (1H) and phosphorus 31 resonances have been used to study brain tissue, but the magnetic resonance sensitivity for protons is far greater than it is for phosphorus. One of the most important contributions of 1H-MRS to clinical neurology is its ability to quantify neuronal loss and to demonstrate reversible neuronal damage. 1H-magnetic resonance spectroscopy has been found to be a useful research tool in elucidating the pathophysiology underlying certain diseases. This review focuses on the use of proton MRS to study various neurologic diseases, including epilepsy, multiple sclerosis, brain tumors, human immunodeficiency virus 1-associated neurologic disorders, as well as cerebrovascular, neurodegenerative, and metabolic diseases. It highlights the contributions of 1H-MRS to the diagnosis and the monitoring of these neurologic diseases that make it a useful adjunct in patient management.

  13. Magnetic Resonance Techniques Applied to the Diagnosis and Treatment of Parkinson’s Disease

    PubMed Central

    de Celis Alonso, Benito; Hidalgo-Tobón, Silvia S.; Menéndez-González, Manuel; Salas-Pacheco, José; Arias-Carrión, Oscar

    2015-01-01

    Parkinson’s disease (PD) affects at least 10 million people worldwide. It is a neurodegenerative disease, which is currently diagnosed by neurological examination. No neuroimaging investigation or blood biomarker is available to aid diagnosis and prognosis. Most effort toward diagnosis using magnetic resonance (MR) has been focused on the use of structural/anatomical neuroimaging and diffusion tensor imaging (DTI). However, deep brain stimulation, a current strategy for treating PD, is guided by MR imaging (MRI). For clinical prognosis, diagnosis, and follow-up investigations, blood oxygen level-dependent MRI, DTI, spectroscopy, and transcranial magnetic stimulation have been used. These techniques represent the state of the art in the last 5 years. Here, we focus on MR techniques for the diagnosis and treatment of Parkinson’s disease. PMID:26191037

  14. Magnetic Resonance Techniques Applied to the Diagnosis and Treatment of Parkinson's Disease.

    PubMed

    de Celis Alonso, Benito; Hidalgo-Tobón, Silvia S; Menéndez-González, Manuel; Salas-Pacheco, José; Arias-Carrión, Oscar

    2015-01-01

    Parkinson's disease (PD) affects at least 10 million people worldwide. It is a neurodegenerative disease, which is currently diagnosed by neurological examination. No neuroimaging investigation or blood biomarker is available to aid diagnosis and prognosis. Most effort toward diagnosis using magnetic resonance (MR) has been focused on the use of structural/anatomical neuroimaging and diffusion tensor imaging (DTI). However, deep brain stimulation, a current strategy for treating PD, is guided by MR imaging (MRI). For clinical prognosis, diagnosis, and follow-up investigations, blood oxygen level-dependent MRI, DTI, spectroscopy, and transcranial magnetic stimulation have been used. These techniques represent the state of the art in the last 5 years. Here, we focus on MR techniques for the diagnosis and treatment of Parkinson's disease.

  15. [Magnetic resonance imaging in the diagnosis of oral carcinoma].

    PubMed

    Daura Sáez, A; Rodríguez San Pedro, F; Asenjo García, B; Aparicio Cambreros, J; Valiente Alvarez, A

    1999-05-01

    Oral cancer accounts for 5% of all tumors in men and 2% in women. We analyzed frequency, sex distribution and cervical lymph node involvement in relation to tumor site. Local extension was diagnosed in 66 patients by MR imaging and the results were compared to CT scan. The results of these studies were correlated with the histopathological study of the specimen in relation to the diagnosis of bone infiltration, tumor size and cervical node infiltration. Bone infiltration was similar in MR images and CT scans. Tumor size was better diagnosed by MR imaging. Detection of cervical lymph node involvement was similar in MR imaging and CT scan.

  16. [Neuromuscular dynamic scapular winging: Clinical, electromyographic and magnetic resonance imaging diagnosis].

    PubMed

    Nguyen, Christelle; Guérini, Henri; Roren, Alexandra; Zauderer, Jennifer; Vuillemin, Valérie; Seror, Paul; Ouaknine, Michaël; Palazzo, Clémence; Bourdet, Christopher; Pluot, Étienne; Roby-Brami, Agnès; Drapé, Jean-Luc; Rannou, François; Poiraudeau, Serge; Lefèvre-Colau, Marie-Martine

    2015-12-01

    Dyskinesia of the scapula is a clinical diagnosis and includes all disorders affecting scapula positioning and movement whatever its etiology. Scapular winging is a subtype of scapular dyskinesia due to a dynamic prominence of the medial border of the scapula (DSW) secondary to neuromuscular imbalance in the scapulothoracic stabilizer muscles. The two most common causes of DSW are microtraumatic or idiopathic lesions of the long thoracic nerve (that innerves the serratus anterior) or the accessory nerve (that innerves the trapezius). Diagnosis of DSW is clinical and electromyographic. Use of magnetic resonance imaging (MRI) could be of interest to distinguish lesion secondary to a long thoracic nerve from accessory nerve and to rule out scapular dyskinesia related to other shoulder disorders. Causal neuromuscular lesion diagnosis in DSW is challenging. Clinical examinations, combined with scapular MRI, could help to their specific diagnosis, determining their stage, ruling out differential diagnosis and thus give raise to more targeted treatment.

  17. Utility of cerebral proton magnetic resonance spectroscopy in differential diagnosis of HIV-related dementia.

    PubMed

    Swindells, S; McConnell, J R; McComb, R D; Gendelman, H E

    1995-09-01

    Opportunistic infections often coexist with human immunodeficiency virus (HIV) infection in brain. Making the correct diagnosis is often difficult despite recent advances in neuroimaging techniques. 1H magnetic resonance spectroscopy (1H MRS) is an emerging non-invasive examination for diagnosis and monitoring of brain disorders. 1H MRS measures a variety of organic compounds using magnetism and radio waves. Biochemical aberrations in brain, not shown by conventional tests, may be demonstrated by 1H MRS testing. A patient coinfected with HIV and hepatitis B (HBV) presented with progressive dementia. Clinical, neuroradiological and cerebrospinal fluid (CSF) examinations failed to provide a diagnosis in support of either HIV-1-associated cognitive/motor complex or HBV-induced hepatic encephalopathy (HE), 1H MRS was used in an attempt to discriminate between these diagnoses. Spectroscopy demonstrated increased glutamine and normal N-acetyl aspartate (NAA) levels, metabolic changes consistent with HE. These findings were later confirmed pathologically. Proton magnetic resonance spectroscopy is a non-invasive test with utility for the differential diagnosis of HIV-associated dementia.

  18. [Magnetic resonance imaging (MRI) in the diagnosis of recurrences of ovarian cancer in the small pelvis].

    PubMed

    Bulanova, I M; Bulanova, T V; Burenchev, D V

    2005-01-01

    The paper provides the results of small pelvic magnetic resonance tomography (MRI) in 62 patients with ovarian cancer after primary special treatment. Out of them 50 patients were found to have recurrences and metastases of the underlying disease, 12 patients had clinical remission. The study yielded MR signs and MR semiotics of recurrences of ovarian cancer in the small pelvis. The capacities of MRI with low and high intensities of a magnetic field were comparatively studied in the diagnosis of recurrences and metastases of ovarian cancer.

  19. Trigger finger following partial flexor tendon laceration: Magnetic resonance imaging-assisted diagnosis

    PubMed Central

    Couceiro, Jose; Fraga, Javier; Sanmartin, Marcos

    2015-01-01

    Introduction Post-traumatic trigger finger is considerably rarer than normal trigger finger. The diagnosis is usually made on a clinical basis. This can be obscured; however, by concurrent pathological conditions. We report a case of post-traumatic trigger finger in which diagnosis was aided by magnetic resonance imaging (MRI). Presentation of case Our patient is a 32-year-old male who had a previous laceration with a subsequent surgery for infectious tenosynovitis. The MRI showed the impinging tendon tag. Surgical excision of the tag successfully solved the case. Discussion The use of imaging studies for the diagnosis of post-traumatic trigger finger has been previously reported, the authors described a variation on the contour of the pulley system. The full lacerated tendon tag can be seen on our patient's MRI. Conclusion On this case, the use of MRI was a useful aid for the differential diagnosis of post-traumattic trigger finger. PMID:25765739

  20. Diagnosis of pericardial cysts using diffusion weighted magnetic resonance imaging: A case series

    PubMed Central

    2011-01-01

    Introduction Congenital pericardial cysts are benign lesions that arise from the pericardium during embryonic development. The diagnosis is based on typical imaging features, but atypical locations and signal magnetic resonance imaging sequences make it difficult to exclude other lesions. Diffusion-weighted magnetic resonance imaging is a novel method that can be used to differentiate tissues based on their restriction to proton diffusion. Its use in differentiating pericardial cysts from other pericardial lesions has not yet been described. Case presentation We present three cases (a 51-year-old Caucasian woman, a 66-year-old Caucasian woman and a 77-year-old Caucasian woman) with pericardial cysts evaluated with diffusion-weighted imaging using cardiac magnetic resonance imaging. Each lesion demonstrated a high apparent diffusion coefficient similar to that of free water. Conclusion This case series is the first attempt to investigate the utility of diffusion-weighted magnetic resonance imaging in the assessment of pericardial cysts. Diffusion-weighted imaging may be a useful noninvasive diagnostic tool for pericardial cysts when conventional imaging findings are inconclusive. PMID:21943086

  1. Development of miniaturized, portable magnetic resonance relaxometry system for point-of-care medical diagnosis.

    PubMed

    Peng, Weng Kung; Chen, Lan; Han, Jongyoon

    2012-09-01

    A novel, compact-sized (19 cm × 16 cm) and portable (500 g) magnetic resonance relaxometry system is designed and developed. We overcame several key engineering barriers so that magnetic resonance technology can be potentially used for disease diagnosis-monitoring in point-of-care settings, directly on biological cells and tissues. The whole system consists of a coin-sized permanent magnet (0.76 T), miniaturized radio-frequency microcoil probe, compact lumped-circuit duplexer, and single board 1-W power amplifier, in which a field programmable gate array -based spectrometer is used for pulse excitation, signal acquisition, and data processing. We show that by measuring the proton transverse relaxation rates from a large pool of natural abundance proton-nuclei presence in less than 1 μL of red blood cells, one can indirectly deduce the relative magnetic susceptibility of the bulk cells within a few minutes of signal acquisition time. Such rapid and sensitive blood screening system can be used to monitor the fluctuation of the bulk magnetic susceptibility of the biological cells (e.g., human blood cells), where unusual state of the bulk magnetic susceptibility is related to a number of diseases.

  2. Computed Tomography Enterography and Magnetic Resonance Enterography in the Diagnosis of Crohn's Disease

    PubMed Central

    2015-01-01

    Imaging of the small bowel is complicated by its length and its overlapping loops. Recently, however, the development of crosssectional imaging techniques, such as computed tomography enterography (CTE) and magnetic resonance enterography (MRE) has shifted fundamental paradigms in the diagnosis and management of patients with suspected or known Crohn's disease (CD). CTE and MRE are noninvasive imaging tests that involve the use of intraluminal oral and intravenous contrast agents to evaluate the small bowel. Here, we review recent advances in each cross-sectional imaging modality, their advantages and disadvantages, and their diagnostic performances in the evaluation of small bowel lesions in CD. PMID:25691841

  3. Magnetic resonance imaging applications in early rheumatoid arthritis diagnosis and management.

    PubMed

    Troum, Orrin M; Pimienta, Olga; Olech, Ewa

    2012-05-01

    Early diagnosis and treatment have been recognized as essential for improving clinical outcomes in patients with rheumatoid arthritis (RA). Magnetic resonance imaging (MRI) is a sensitive modality that can assess both inflammatory and structural lesions. MRI can assist in following the disease course in patients treated with traditional disease-modifying antirheumatic drugs and biological therapies both in the clinic and in research trials. Therefore, it is anticipated that MRI becomes the diagnostic imaging modality of choice in RA clinical trials while remaining a useful tool for clinicians evaluating patients with RA.

  4. Magnetic hydroxyapatite nanoworms for magnetic resonance diagnosis of acute hepatic injury

    NASA Astrophysics Data System (ADS)

    Xu, Yun-Jun; Dong, Liang; Lu, Yang; Zhang, Le-Cheng; An, Duo; Gao, Huai-Ling; Yang, Dong-Mei; Hu, Wen; Sui, Cong; Xu, Wei-Ping; Yu, Shu-Hong

    2016-01-01

    Inorganic non-metallic biomaterials, including the silicon frustule of a unicellular diatom, the carbonate shell of a mollusk and the calcium skeleton of the vertebrate, which are the main constituent part of an organism, serve as the supportive and protective components of soft tissue. Among them, hydroxyapatite, which primarily makes up the enamel and bone, is widely used in tissue engineering. Recently, the inorganic nonmetallic biomaterials, especially the applications of hydroxyapatites have attracted great attention. Herein, we report a novel synthesis method of magnetic functionalized hydroxyapatite nanocomposites. By simply tuning the ratios of reactants, a series of hydroxyapatite-Fe3O4 worm-shaped nanocomposites (HAP-ION nanoworms) are obtained. In addition, layer-by-layer surface modifications with chitosan (CH) and sodium alginate (SA) were employed to improve the solubility and biocompatibility, and low cytotoxicity and no hemolysis were observed. With the increase of iron oxide nanocrystals, the magnetic properties of the magnetic assembled nanoworms were enhanced, which resulted in better performance of magnetic resonance (MR) imaging. Owing to the intravenous injection of HAP-ION nanoworms, the contrast to noise ratio (CNR) of hepatic MR imaging in vivo was enhanced obviously, which should be beneficial for hepatic injury grading and further therapeutic treatment.Inorganic non-metallic biomaterials, including the silicon frustule of a unicellular diatom, the carbonate shell of a mollusk and the calcium skeleton of the vertebrate, which are the main constituent part of an organism, serve as the supportive and protective components of soft tissue. Among them, hydroxyapatite, which primarily makes up the enamel and bone, is widely used in tissue engineering. Recently, the inorganic nonmetallic biomaterials, especially the applications of hydroxyapatites have attracted great attention. Herein, we report a novel synthesis method of magnetic

  5. Computer-based magnetic resonance imaging as a tool in clinical diagnosis in neurodegenerative diseases.

    PubMed

    Kassubek, Jan; Müller, Hans-Peter

    2016-01-01

    Magnetic resonance imaging (MRI) is one of the core elements within the differential diagnostic work-up of patients with neurodegenerative diseases such as dementia syndromes, Parkinsonian syndromes, and motor neuron diseases. Currently, computerized MRI analyses are not routinely used for individual diagnosis; however, they have improved the anatomical understanding of pathomorphological alterations in various neurodegenerative diseases by quantitative comparisons between patients and controls at the group level. For multiparametric MRI protocols, including T1-weighted MRI, diffusion-weighted imaging, and intrinsic functional connectivity MRI, the potential as a surrogate marker is a subject of investigation. The additional value of MRI with respect to diagnosis at the individual level and for future disease-modifying multicentre trials remains to be defined. Here, we give an overview of recent applications of multiparametric MRI to patients with various neurodegenerative diseases. Starting from applications at the group level, continuous progress of a transfer to individual diagnostic classification is ongoing.

  6. Role of Imaging Techniques for Diagnosis, Prognosis and Management of Heart Failure Patients: Cardiac Magnetic Resonance

    PubMed Central

    Gonzalez, Jorge A.; Kramer, Christopher M.

    2015-01-01

    Cardiac Magnetic Resonance (CMR) has evolved into a major tool for the diagnosis and assessment of prognosis of patients suffering from heart failure. Anatomical and structural imaging, functional assessment, T1 and T2 mapping tissue characterization and late gadolinium enhancement (LGE) have provided clinicians with tools to distinguish between non-ischemic and ischemic cardiomyopathies and to identify the etiology of non-ischemic cardiomyopathies. LGE is a useful tool to predict the likelihood of functional recovery after revascularization in patients with CAD and to guide the LV lead placement in those who qualify for cardiac resynchronization (CRT) therapy. In addition, the presence of LGE and its extent in myocardial tissue relates to overall cardiovascular outcomes. Emerging roles for cardiac imaging in Heart Failure with Preserved Ejection Fraction (HFpEF) are being studied and CMR continues to be among the most promising noninvasive imaging alternatives in the diagnosis of this disease. PMID:26041670

  7. Automated diagnosis and prediction of Alzheimer disease using magnetic resonance image

    NASA Astrophysics Data System (ADS)

    Cai, Zifan; Di, Qian; Chen, Kewei; Reiman, Eric M.; Wang, Liang; Li, Kuncheng; Tang, Jie; Yao, Li; Zhao, Xiaojie

    2007-03-01

    Magnetic resonance image (MRI) has provided an imageological support into the clinical diagnosis and prediction of Alzheimer disease (AD) progress. Currently, the clinical use of MRI data on AD diagnosis is qualitative via visual inspection and less accurate. To provide assistance to physicians in improving the accuracy and sensitivity of the AD diagnose and the clinical outcome of the disease, we developed a computer-assisted analysis package that analyzed the MRI data of an individual patient in comparison with a group of normal controls. The package is based on the principle of the well established and widely used voxel-based morphometry (VBM) and SPM software. All analysis procedure is automated and streamlined. With only one mouse-click, the whole procedure was finished within 15 minutes. With the interactive display and anatomical automatic labeling toolbox, the final result and report supply the brain regional structure difference, the quantitative assessment and visual inspections by physicians and scientific researcher. The brain regions which affected by AD are consonant in the main with the clinical diagnosis, which are reviewed by physicians. In result, the computer package provides physician with an automatic and assistant tool for prediction using MRI. This package could be valuable tool assisting physicians in making their clinical diagnosis decisions.

  8. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in Dementias

    PubMed Central

    Hsu, Yuan-Yu; Du, An-Tao; Schuff, Norbert; Weiner, Michael W.

    2007-01-01

    This article reviews recent studies of magnetic resonance imaging and magnetic resonance spectroscopy in dementia, including Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, idiopathic Parkinson's disease, Huntington's disease, and vascular dementia. Magnetic resonance imaging and magnetic resonance spectroscopy can detect structural alteration and biochemical abnormalities in the brain of demented subjects and may help in the differential diagnosis and early detection of affected individuals, monitoring disease progression, and evaluation of therapeutic effect. PMID:11563438

  9. [New ASAS criteria for the diagnosis of spondyloarthritis: diagnosing sacroiliitis by magnetic resonance imaging].

    PubMed

    Banegas Illescas, M E; López Menéndez, C; Rozas Rodríguez, M L; Fernández Quintero, R M

    2014-01-01

    Radiographic sacroiliitis has been included in the diagnostic criteria for spondyloarthropathies since the Rome criteria were defined in 1961. However, in the last ten years, magnetic resonance imaging (MRI) has proven more sensitive in the evaluation of the sacroiliac joints in patients with suspected spondyloarthritis and symptoms of sacroiliitis; MRI has proven its usefulness not only for diagnosis of this disease, but also for the follow-up of the disease and response to treatment in these patients. In 2009, The Assessment of SpondyloArthritis international Society (ASAS) developed a new set of criteria for classifying and diagnosing patients with spondyloarthritis; one important development with respect to previous classifications is the inclusion of MRI positive for sacroiliitis as a major diagnostic criterion. This article focuses on the radiologic part of the new classification. We describe and illustrate the different alterations that can be seen on MRI in patients with sacroiliitis, pointing out the limitations of the technique and diagnostic pitfalls.

  10. Craniosynostosis: prenatal diagnosis by 2D/3D ultrasound, magnetic resonance imaging and computed tomography.

    PubMed

    Helfer, Talita Micheletti; Peixoto, Alberto Borges; Tonni, Gabriele; Araujo Júnior, Edward

    2016-09-01

    Craniosynostosis is defined as the process of premature fusion of one or more of the cranial sutures. It is a common condition that occurs in about 1 to 2,000 live births. Craniosynostosis may be classified in primary or secondary. It is also classified as nonsyndromic or syndromic. According to suture commitment, craniosynostosis may affect a single suture or multiple sutures. There is a wide range of syndromes involving craniosynostosis and the most common are Apert, Pffeifer, Crouzon, Shaethre-Chotzen and Muenke syndromes. The underlying etiology of nonsyndromic craniosynostosis is unknown. Mutations in the fibroblast growth factor (FGF) signalling pathway play a crucial role in the etiology of craniosynostosis syndromes. Prenatal ultrasound`s detection rate of craniosynostosis is low. Nowadays, different methods can be applied for prenatal diagnosis of craniosynostosis, such as two-dimensional (2D) and three-dimensional (3D) ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) scan and, finally, molecular diagnosis. The presence of craniosynostosis may affect the birthing process. Fetuses with craniosynostosis also have higher rates of perinatal complications. In order to avoid the risks of untreated craniosynostosis, children are usually treated surgically soon after postnatal diagnosis.

  11. Non-invasive magnetic resonance imaging diagnosis of presumed intermedioradial carpal bone avascular necrosis in the dog

    PubMed Central

    Pownder, Sarah L.; Cooley, Stacy; Hayashi, Kei; Bezuidenhout, Abraham; Koff, Matthew F.; Potter, Hollis G.

    2016-01-01

    A 5-year-old, spayed female Weimaraner dog was evaluated for progressive left forelimb lameness localized to the carpus. Magnetic resonance imaging (MRI) was used to arrive at a presumptive diagnosis of intermedioradial carpal (IRC) bone fracture with avascular necrosis (AVN). To the authors’ knowledge, this is the first report of naturally occurring AVN of the canine IRC diagnosed using MRI. PMID:27493290

  12. Magnetic resonance imaging in the diagnosis and staging of renal and perirenal neoplasms.

    PubMed

    Hricak, H; Demas, B E; Williams, R D; McNamara, M T; Hedgcock, M W; Amparo, E G; Tanagho, E A

    1985-03-01

    Thirty-one adult patients underwent magnetic resonance (MR) imaging after CT scans had demonstrated findings consistent with renal cell carcinoma. MR images were interpreted prospectively and independently of the CT findings. Because the CT scanning was performed at multiple institutions by many examiners, this study was not a direct comparison of CT versus MR. The preoperative diagnoses and staging of the neoplasms, as judged by MR, were compared with those obtained at laparotomy (n = 28), autopsy (n = 1), or biopsy (n = 2). Correct preoperative diagnoses were rendered in 31 patients (100%) on the basis of MR findings. The anatomic staging of 27 renal cell carcinomas was correctly performed by MR in 26 patients (86%). When compared with results of previous studies of the value of CT in the diagnosis and staging of renal neoplasms, MR appears to have several advantages in determination of the origin of the mass; the evaluation of vascular patency; the detection of perihilar lymph node metastases; and the evaluation of direct tumor invasion of adjacent organs. MR is sensitive in determining the extent of tumor thrombus and in evaluating invasion of the inferior vena caval wall. MR should assume an important role in the diagnosis and staging of renal neoplasms.

  13. Enhancing malaria diagnosis through microfluidic cell enrichment and magnetic resonance relaxometry detection

    NASA Astrophysics Data System (ADS)

    Fook Kong, Tian; Ye, Weijian; Peng, Weng Kung; Wei Hou, Han; Marcos; Preiser, Peter Rainer; Nguyen, Nam-Trung; Han, Jongyoon

    2015-06-01

    Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical samples. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between individuals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each individual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future.

  14. Enhancing malaria diagnosis through microfluidic cell enrichment and magnetic resonance relaxometry detection

    PubMed Central

    Fook Kong, Tian; Ye, Weijian; Peng, Weng Kung; Wei Hou, Han; Marcos, M; Preiser, Peter Rainer; Nguyen, Nam-Trung; Han, Jongyoon

    2015-01-01

    Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical samples. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between individuals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each individual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future. PMID:26081638

  15. Diagnosis of intestinal ischemia in the rat using magnetic resonance imaging.

    PubMed

    Park, A; Towner, R A; Langer, J C

    1993-01-01

    Noninvasive diagnosis of persistent ischemia after intestinal revascularization has remained an elusive goal. Because magnetic resonance imaging (MRI) can detect changes in tissue water, we studied its efficacy in differentiating ischemic from perfused intestine in an animal model. Six-week-old rats were subjected to (1) 30-min superior mesenteric artery (SMA) occlusion and reperfusion, (2) permanent SMA ligation, or (3) sham operation, and were then imaged for 90 min using a small-animal MRI scanner with T1 weighting (TR = 1000 msec, TE = 25 msec). In an additional group of rats, the experiment was repeated using a new contrast technique consisting of oral ferrite to decrease luminal signal and intravenous gadolinium to increase bowel wall signal. Mean abdominal intensity over the scanning period was calculated for each animal (n = 5 rats per experimental group). Definition of individual bowel loops was subjectively improved in animals scanned with intravenous and oral contrast. Mean abdominal intensity was significantly lower in ligated vs sham rats (43.90 +/- 8 vs 59.63 +/- 6 and 46.19 +/- 6 vs 54.26 +/- 6, with and without contrast, respectively). There was no significant difference in intensity between reperfused and sham animals. MRI differentiated persistently ischemic bowel from viable bowel in this model, both with and without the use of contrast. These data suggest that MRI may have a potential role in the noninvasive diagnosis of persistent intestinal ischemia.

  16. Magnetic resonance imaging in myelofibrosis and essential thrombocythaemia: contribution to differential diagnosis.

    PubMed

    Rozman, C; Cervantes, F; Rozman, M; Mercader, J M; Montserrat, E

    1999-03-01

    To ascertain the value of magnetic resonance (MR) imaging in the differential diagnosis between myelofibrosis (MF) and essential thrombocythaemia (ET), 38 patients were analysed. 20 patients had MF (idiopathic myelofibrosis, 15 cases; post-ET myelofibrosis, four cases; post-polycythaemic MF, one case) and 18 ET. Mean age was 61.5 years (range 30-89) for patients with MF and 60.9 years (range 26-83) for ET patients. MR imaging was performed in the dorsal vertebrae in all cases, and also in both femurs in 2 5 of the patients. In most ET cases the MR signal of the dorsal vertebrae was not modified, whereas it was markedly reduced in MF (P=0.0000001). With regard to femoral marrow, it was usually fatty in ET, with an absent to moderate degree of reconversion seen in the 14 cases analysed, contrasting with the marked degree of reconversion noted in 10/11 patients with MF (P=0.000007). An inverse correlation was demonstrated between the vertebral signal and the degree of femoral reconversion. These differences were due to the fact that in ET the bone marrow adipose tissue is grossly preserved, whereas in MF it is usually markedly decreased or absent. The above results indicate that MR imaging is a useful tool for the differential diagnosis of ET and MF, with the usefulness of this technique increasing when vertebral and femoral bone marrow studies are combined.

  17. A magnetic-field enriched surface-enhanced resonance Raman spectroscopy strategy towards the early diagnosis of malaria

    NASA Astrophysics Data System (ADS)

    Clement, Yuen; Liu, Quan

    2012-02-01

    Early malaria diagnosis is important because malaria disease can develop into fatal illness within hours upon the appearance of the first symptom. The low concentration of the diagnosis biomarker, hemozoin, at the early stage of malaria disease makes early diagnosis difficult. In this paper, we present a magnetic field-enriched surface-enhanced resonance Raman spectroscopy (SERRS) strategy for the sensitive detection of β - hematin crystals, which is equivalent to hemozoin in the characteristics of Raman spectrum, by using magnetic nanoparticles. We observe several orders of magnitude enhancement in the SERRS signal of enriched β - hematin in comparison to the Raman signal of β - hematin in the cases of SERRS alone or magnetic enrichment alone, showing the great potential of this method towards early malaria diagnosis.

  18. A magnetic-field enriched surface-enhanced resonance Raman spectroscopy strategy towards the early diagnosis of malaria

    NASA Astrophysics Data System (ADS)

    Yuen, Clement; Liu, Quan

    2012-03-01

    Early malaria diagnosis is important because malaria disease can develop into fatal illness within hours upon the appearance of the first symptom. The low concentration of the diagnosis biomarker, hemozoin, at the early stage of malaria disease makes early diagnosis difficult. In this paper, we present a magnetic field-enriched surface-enhanced resonance Raman spectroscopy (SERRS) strategy for the sensitive detection of β - hematin crystals, which is equivalent to hemozoin in the characteristics of Raman spectrum, by using magnetic nanoparticles. We observe several orders of magnitude enhancement in the SERRS signal of enriched β - hematin in comparison to the Raman signal of β - hematin in the cases of SERRS alone or magnetic enrichment alone, showing the great potential of this method towards early malaria diagnosis.

  19. Magnetic resonance imaging

    SciTech Connect

    Stark, D.D.; Bradley, W.G. Jr.

    1988-01-01

    The authors present a review of magnetic resonance imaging. Many topics are explored from instrumentation, spectroscopy, blood flow and sodium imaging to detailed clinical applications such as the differential diagnosis of multiple sclerosis or adrenal adenoma. The emphasis throughout is on descriptions of normal multiplanar anatomy and pathology as displayed by MRI.

  20. Comparing Magnetic Resonance Imaging and High-Resolution Dynamic Ultrasonography for Diagnosis of Plantar Plate Pathology: A Case Series.

    PubMed

    Donegan, Ryan J; Stauffer, Anthony; Heaslet, Michael; Poliskie, Michael

    Plantar plate pathology has gained noticeable attention in recent years as an etiology of lesser metatarsophalangeal joint pain. The heightened clinical awareness has led to the need for more effective diagnostic imaging accuracy. Numerous reports have established the accuracy of both magnetic resonance imaging and ultrasonography for the diagnosis of plantar plate pathology. However, no conclusions have been made regarding which is the superior imaging modality. The present study reports a case series directly comparing high-resolution dynamic ultrasonography and magnetic resonance imaging. A multicenter retrospective comparison of magnetic resonance imaging versus high-resolution dynamic ultrasonography to evaluate plantar plate pathology with surgical confirmation was conducted. The sensitivity, specificity, and positive and negative predictive values for magnetic resonance imaging were 60%, 100%, 100%, and 33%, respectively. The overall diagnostic accuracy compared with the intraoperative findings was 66%. The sensitivity, specificity, and positive and negative predictive values for high-resolution dynamic ultrasound imaging were 100%, 100%, 100%, and 100%, respectively. The overall diagnostic accuracy compared with the intraoperative findings was 100%. The p value using Fisher's exact test for magnetic resonance imaging and high-resolution dynamic ultrasonography was p = .45, a difference that was not statistically significant. High-resolution dynamic ultrasonography had greater accuracy than magnetic resonance imaging in diagnosing lesser metatarsophalangeal joint plantar plate pathology, although the difference was not statistically significant. The present case series suggests that high-resolution dynamic ultrasonography can be considered an equally accurate imaging modality for plantar plate pathology at a potential cost savings compared with magnetic resonance imaging. Therefore, high-resolution dynamic ultrasonography warrants further investigation in

  1. Magnetic resonance imaging and positron emission tomography in the diagnosis of neurodegenerative dementias

    PubMed Central

    Del Sole, Angelo; Malaspina, Simona; Biasina, Alberto Magenta

    2016-01-01

    Summary Neuroimaging, both with magnetic resonance imaging (MRI) and positron emission tomography (PET), has gained a pivotal role in the diagnosis of primary neurodegenerative diseases. These two techniques are used as biomarkers of both pathology and progression of Alzheimer’s disease (AD) and to differentiate AD from other neurodegenerative diseases. MRI is able to identify structural changes including patterns of atrophy characterizing neurodegenerative diseases, and to distinguish these from other causes of cognitive impairment, e.g. infarcts, space-occupying lesions and hydrocephalus. PET is widely used to identify regional patterns of glucose utilization, since distinct patterns of distribution of cerebral glucose metabolism are related to different subtypes of neurodegenerative dementia. The use of PET in mild cognitive impairment, though controversial, is deemed helpful for predicting conversion to dementia and the dementia clinical subtype. Recently, new radiopharmaceuticals for the in vivo imaging of amyloid burden have been licensed and more tracers are being developed for the assessment of tauopathies and inflammatory processes, which may underlie the onset of the amyloid cascade. At present, the cerebral amyloid burden, imaged with PET, may help to exclude the presence of AD as well as forecast its possible onset. Finally PET imaging may be particularly useful in ongoing clinical trials for the development of dementia treatments. In the near future, the use of the above methods, in accordance with specific guidelines, along with the use of effective treatments will likely lead to more timely and successful treatment of neurodegenerative dementias. PMID:28072381

  2. Magnetic Resonance Imaging as a Major Milestone in Multiple Sclerosis Diagnosis and Treatment

    PubMed Central

    KARABUDAK, Rana

    2015-01-01

    Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Magnetic resonance imaging (MRI) has played a unique role in the diagnosis and management of patients with MS. In recent years, there have been considerable changes in the diagnostic criteria for MS as MRI-based studies have demonstrated their power in the earlier and more accurate diagnosis of the disease. Moreover, MRI metrics have become key supportive outcome measures for evaluating the efficacy of experimental treatments in randomized controlled trials. MRI can also be used as a prognostic tool in patients with clinically isolated syndrome (CIS). Conventional MR techniques including proton density, T1/T2-weighted images, and FLAIR sequences are now accepted in standard protocols for diagnostic and treatment outcome measures in clinical trials for MS. Radiological features may show a similarity between radiologically isolated syndrome and MS. Approximately two-thirds of individuals with RIS exhibit radiological progression and one-third develop neurological symptoms during mean follow-up times of up to five years. However, a current challenge in the global application of established criteria for RIS involves the accurate classification of subjects with incidentally identified anomalies that are highly characteristic of MS, in comparison to those categorized in medical parlance as possessing “unidentified bright objects” or nonspecific T2-hyperintensities, which are commonly identified in patients with migraine headache who fulfill the spatial dissemination requirements for MS. The need for systematically acquired data for improvements in the classification of radiologically isolated syndrome (RIS) and the generation of risk algorithms are critically important, providing a basis for scientifically supported management and most importantly, minimizing the number of improperly classified subjects exposed to unnecessary medical testing, MS treatments, and

  3. Application of Texture Analysis in Diagnosis of Multiple Sclerosis by Magnetic Resonance Imaging

    PubMed Central

    Ardakani, Ali Abbasian; Gharbali, Akbar; Saniei, Yalda; Mosarrezaii, Arash; Nazarbaghi, Surena

    2015-01-01

    Introduction: Visual inspection by magnetic resonance (MR) images cannot detect microscopic tissue changes occurring in MS in normal appearing white matter (NAWM) and may be perceived by the human eye as having the same texture as normal white matter (NWM). The aim of the study was to evaluate computer aided diagnosis (CAD) system using texture analysis (TA) in MR images to improve accuracy in identification of subtle differences in brain tissue structure. Material and Methods: The MR image database comprised 50 MS patients and 50 healthy subjects. Up to 270 statistical texture features extract as descriptors for each region of interest. The feature reduction methods used were the Fisher method, the lowest probability of classification error and average correlation coefficients (POE+ACC) method and the fusion Fisher plus the POE+ACC (FFPA) to select the best, most effective features to differentiate between MS lesions, NWM and NAWM. The features parameters were used for texture analysis with principle component analysis (PCA) and linear discriminant analysis (LDA). Then first nearest-neighbour (1-NN) classifier was used for features resulting from PCA and LDA. Receiver operating characteristic (ROC) curve analysis was used to examine the performance of TA methods. Results: The highest performance for discrimination between MS lesions, NAWM and NWM was recorded for FFPA feature parameters using LDA; this method showed 100% sensitivity, specificity and accuracy and an area of Az = 1 under the ROC curve. Conclusion: TA is a reliable method with the potential for effective use in MR imaging for the diagnosis and prediction of MS. PMID:26153164

  4. MRI (Magnetic Resonance Imaging)

    MedlinePlus

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  5. Cardiovascular magnetics resonance diagnosis of cystic tumor of the atrioventricular node.

    PubMed

    Tran, Thao T; Starnes, Vaughn; Wang, Xuedong; Getzen, James; Ross, Brian D

    2009-04-30

    Late gadolinium enhanced (LGE) cardiovascular magnetic resonance (CMR) has proven to be the gold standard for viability assessment. LGE CMR is also useful for identifying the nature of cardiac masses or lesions. We report a case of a rare primary cystic tumor of the atrioventricular node, in which CMR proved to be valuable.

  6. [Role of computeric tomography and magnetic resonance imaging in diagnosis of inflammatory diseases of sacro-ileal joint].

    PubMed

    Baĭramov, R B

    2012-05-01

    Sensitivity of computeric tomography (CT) and magnetic resonance imaging (MRI) for sacroileitis diagnosis was studied, optimal for MRI investigation was established. In 31 patients, owing obvious clinical signs of inflammatory sacroileitis (at average more than 5 mo duration of a low back pain) MRI of sacroiliac joint was conducted in a T1, T2 FS, 2D T2 FLASH regimes and after intravenous infusion of a contrast substance (gadolinium) - in a T1 FS regime, using system, owing a 1,5 T magnetic field intensity. The data obtained were compared with results of CT. Sacroileitis signs were revealed in 27 patients - according to CT data, and in 22 - MRI. CT have demonstrated as a more sensitive method of the bone erosion and sclerosis diagnosis, than MRI. MRI is more sensitive while revealing an active inflammatory process in the bone and joint space. While T1 FS application no additional information for sacroileitis diagnosis was obtained.

  7. How Doctors Generate Diagnostic Hypotheses: A Study of Radiological Diagnosis with Functional Magnetic Resonance Imaging

    PubMed Central

    Melo, Marcio; Scarpin, Daniel J.; Amaro, Edson; Passos, Rodrigo B. D.; Sato, João R.; Friston, Karl J.; Price, Cathy J.

    2011-01-01

    Background In medical practice, diagnostic hypotheses are often made by physicians in the first moments of contact with patients; sometimes even before they report their symptoms. We propose that generation of diagnostic hypotheses in this context is the result of cognitive processes subserved by brain mechanisms that are similar to those involved in naming objects or concepts in everyday life. Methodology and Principal Findings To test this proposal we developed an experimental paradigm with functional magnetic resonance imaging (fMRI) using radiological diagnosis as a model. Twenty-five radiologists diagnosed lesions in chest X-ray images and named non-medical targets (animals) embedded in chest X-ray images while being scanned in a fMRI session. Images were presented for 1.5 seconds; response times (RTs) and the ensuing cortical activations were assessed. The mean response time for diagnosing lesions was 1.33 (SD ±0.14) seconds and 1.23 (SD ±0.13) seconds for naming animals. 72% of the radiologists reported cogitating differential diagnoses during trials (3.5 seconds). The overall pattern of cortical activations was remarkably similar for both types of targets. However, within the neural systems shared by both stimuli, activation was significantly greater in left inferior frontal sulcus and posterior cingulate cortex for lesions relative to animals. Conclusions Generation of diagnostic hypotheses and differential diagnoses made through the immediate visual recognition of clinical signs can be a fast and automatic process. The co-localization of significant brain activation for lesions and animals suggests that generating diagnostic hypotheses for lesions and naming animals are served by the same neuronal systems. Nevertheless, diagnosing lesions was cognitively more demanding and associated with more activation in higher order cortical areas. These results support the hypothesis that medical diagnoses based on prompt visual recognition of clinical signs and

  8. Differential diagnosis of parotid gland tumours: which magnetic resonance findings should be taken in account?

    PubMed

    Tartaglione, T; Botto, A; Sciandra, M; Gaudino, S; Danieli, L; Parrilla, C; Paludetti, G; Colosimo, C

    2015-10-01

    Our aim was to define typical magnetic resonance (MRI) findings in malignant and benign parotid tumours. This study is based on retrospective evaluation of pre-surgical MRI of 94 patients with parotid gland tumours. Histology results were available for all tumours. There were 69 cases of benign (73%) and 25 cases of malignant (27%) tumours, including 44 pleomorphic adenomas, 18 Warthin's tumours, 7 various benign tumours, 6 squamous cell carcinomas, 3 carcinoma ex pleomorphic adenomas, 2 mucoepidermoid carcinomas, 1 adenoid cystic carcinoma and 13 various malignant tumours. The following MRI parameters were evaluated: shape, site, size, margins, signal intensity (SI) on T1w and T2w images, contrast enhancement, signal of cystic content, presence or absence of a capsule, perineural spread, extraglandular growth pattern and cervical adenopathy. Statistical analysis was performed to identify the MRI findings most suggestive of malignancy, and to define the most typical MRI pattern of the most common histologies. Ill-defined margins (p < 0.001), adenopathies (p < 0.001) and infiltrative grown pattern (p < 0.001) were significantly predictive of malignancy. Typical findings of pleomorphic adenoma included hyperintensity on T2w images (p = 0.02), strong contrast enhancement (p < 0.001) and lobulated shape (p = 0.04). Typical findings of Warthin's tumour included hyperintense components on T1w images (p < 0.001), location in the parotid inferior process (p < 0.001) and mild or incomplete contrast enhancement (p = 0.01). SI on T1w and T2w images and contrast enhancement enables differential diagnosis between pleomorphic adenoma and Warthin's tumour.

  9. Diagnosis of Popliteal Venous Entrapment Syndrome by Magnetic Resonance Imaging Using Blood-Pool Contrast Agents

    SciTech Connect

    Beitzke, Dietrich Wolf, Florian; Juelg, Gregor; Lammer, Johannes; Loewe, Christian

    2011-02-15

    Popliteal vascular entrapment syndrome is caused by aberrations or hypertrophy of the gastrocnemius muscles, which compress the neurovascular structures of the popliteal fossa, leading to symptoms of vascular and degeneration as well as aneurysm formation. Imaging of popliteal vascular entrapment may be performed with ultrasound, magnetic resonance imaging (MRI), computed tomography angiography, and conventional angiography. The use of blood-pool contrast agents in MRI when popliteal vascular entrapment is suspected offers the possibility to perform vascular imaging with first-pass magnetic resonance angiographic, high-resolution, steady-state imaging and allows functional tests all within one examination with a single dose of contrast agent. We present imaging findings in a case of symptomatic popliteal vein entrapment diagnosed by the use of blood pool contrast-enhanced MRI.

  10. Magnetic resonance imaging in the new paradigm for the diagnosis of prostate cancer.

    PubMed

    Vilanova, J C; Catalá, V

    For various reasons, prostate cancer is a major public health problem. It is a very common cancer, but has a very low mortality rate because it comprises two types of disease: one insignificant, indolent, and much more common, and the other aggressive, significant, and much less common. The routine diagnostic approach to prostate cancer has been systematic blind biopsies, which has low detection rates and might detect low risk, insignificant prostate cancer, leading to overdiagnosis and overtreatment of indolent cancers. The possibility of including multiparametric magnetic resonance imaging in the diagnostic management to improve the detection of aggressive cancer while reducing the overdiagnosis of indolent cancer represents a change in the diagnostic management. This article updates knowledge about the diagnostic management of prostate cancer including multiparametric magnetic resonance imaging.

  11. Diagnosis of Alzheimer-type dementia: a preliminary comparison of positron emission tomography and proton magnetic resonance

    SciTech Connect

    Friedland, R.P.; Budinger, T.F.; Brant-Zawadzki, M.; Jagust, W.J.

    1984-11-16

    The use of positron emission tomography with (18F)-2-fluoro-2-deoxy-D-glucose (FDG) to study glucose metabolism in dementia is described and compared with the use of magnetic resonance imaging. These studies suggest that physiological imaging with PET may be superior to MR as it is currently used in the diagnosis of dementia-like diseases. Pet is currently limited to a few centers; however, single photon emission CT can provide regional physiological data without the need for a local cyclotron. 15 references, 2 tables.

  12. Diagnosis of brainstem abscess in the cerebritis stage by magnetic resonance imaging--case report.

    PubMed

    Adachi, J; Uki, J; Kazumoto, K; Takeda, F

    1995-07-01

    A 52-year-old male presented with a brainstem abscess manifesting as high fever, diplopia, and left hemiparesis. Magnetic resonance (MR) imaging with gadolinium diethylenetriamine pentaacetic acid showed the lesion as a ring-like enhanced mass consisting of a necrotic center with surrounding edema, whereas postcontrast computed tomography revealed no such confirmatory findings. He was treated with antibiotics as the lesion had been detected in the acute cerebritis stage. Serial MR images showed that the lesion decreased remarkably in size. MR imaging can detect brain abscess in the earliest inflammatory stage.

  13. IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING FEATURES OF CRANIOMANDIBULAR OSTEOPATHY IN AN AIREDALE TERRIER.

    PubMed

    Matiasovic, Matej; Caine, Abby; Scarpante, Elena; Cherubini, Giunio Bruto

    2016-05-01

    An Airedale Terrier was presented for evaluation of depression and reluctance to be touched on the head. Magnetic resonance (MR) imaging of the head was performed. The images revealed bone lesions affecting the calvarium at the level of the coronal suture and left mandibular ramus, with focal cortical destruction, expansion, and reactive new bone formation. Skull lesions were hypointense on T1-weighted sequences, hyperintense on T2-weighted sequences, and showed an intense and homogeneous enhancement after gadolinium administration. Reactive new bone formation and periosteal proliferation were confirmed histopathologically. The clinical signs, imaging findings, and histopathological examination were consistent with craniomandibular osteopathy.

  14. [Value of magnetic resonance imaging in the diagnosis of sequels of shoulder joint injuries].

    PubMed

    Murashina, I V; Egorova, E A

    2011-01-01

    The paper presents the results of examining 45 persons with sequels of shoulder joint injuries, by applying magnetic resonance imaging (MRI) (100%) and arthroscopy (95.6%). The data of arthroscopy were compared with those of MRI; thereafter the sensitivity, specificity, and accuracy of MRI were calculated. The findings suggested that there was no statistically significant difference in the capacities of the two comparable techniques MRI and arthroscopy to diagnose labral tears with degenerative changes, synovitis, bursitis and tendinitis (McNemar's test; p > 0.05). The capacities of MRI are greater than those of arthroscopy only to detect the structural disintegrity of the joint shoulder.

  15. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

    1997-12-30

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

  16. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, Paul H.; Brainard, James R.; Jarvinen, Gordon D.; Ryan, Robert R.

    1997-01-01

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

  17. Cerebral abnormalities: use of calculated T1 and T2 magnetic resonance images for diagnosis

    SciTech Connect

    Mills, C.M.; Crooks, L.E.; Kaufman, L.; Brant-Zawadzki, M.

    1984-01-01

    The potential clinical importance of T1 and T2 relaxation times in distinguishing normal and pathologic tissue with magnetic resonance (MR) is discussed and clinical examples of cerebral abnormalities are given. Five patients with cerebral infarction, 15 with multiple sclerosis, two with Wilson disease, and four with tumors were imaged. Hemorrhagic and ischemic cerebrovascular accidents were distinguished using the spin echo technique. In the patients with multiple sclerosis, lesions had prolonged T1 and T2 times, but the definition of plaque was limited by spatial resolution. No abnormalities in signal intensity were seen in the patient with Wilson disease who was no longer severly disabled; abnormal increased signal intensity in the basal ganglia was found in the second patient with Wilson disease. Four tumors produced abnormal T1 and T2 relaxation times but these values alone were not sufficient for tumor characterization.

  18. Premature partial physeal arrest. Diagnosis by magnetic resonance imaging in two cases.

    PubMed

    Gabel, G T; Peterson, H A; Berquist, T H

    1991-11-01

    The management of premature physeal arrest requires accurate assessment of not only the location but also the extent of the bar. Numerous imaging techniques are available to evaluate the physis. Multiplanar tomography has proven to be the most precise method. The utility of magnetic resonance imaging (MRI) of physeal bars has not been demonstrated. This article presents MRI results in two cases of physeal bars. MRI provides a means of assessing physeal bar formation with an accuracy approaching that of multiplanar tomography. In certain instances, its efficacy may exceed that of tomography, specifically when the physis cannot be properly oriented for tomographic evaluation, when more planes are desired, and when radiation exposure is thought to be excessive. With improvement of its capabilities and availability (which may also reduce cost), it may become the diagnostic imaging technique of choice.

  19. IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING OF A NEURONAL HETEROTOPIA IN THE BRAIN OF A CAT.

    PubMed

    DeJesus, Antonia; Turek, Bradley J; Galban, Evelyn; Suran, Jantra Ngosuwan

    2016-11-28

    A domestic shorthair kitten was presented for evaluation and further treatment of seizures. Magnetic resonance imaging of the brain revealed a large multilobulated mass in the third ventricle extending into the right lateral ventricle with secondary obstructive hydrocephalus. The mass was homogeneously isointense to gray matter on T2W, T2-FLAIR, T2(*) W, T1W, and ADC images, and hyperintense on DW-EPI. There was no appreciable contrast enhancement. Seizures were managed medically and with subsequent ventriculoperitoneal shunt placement. Clinical status later deteriorated and the cat was euthanized. Histopathology confirmed that the mass was the result of neuronal heterotopia. To the authors' knowledge this is the first report of neuronal heterotopia in a cat.

  20. [Multiparameter magnetic resonance imaging in the diagnosis of cancer of the cervix uteri].

    PubMed

    Tarachkova, E V; Strel'tsova, O N; Panov, V O; Bazaeva, I Ya; Tyurin, I E

    2015-01-01

    Cancer of the cervix uteri (CCU) ranks third in the incidence of malignancies in women. The choice of CCU treatment mainly depends on the extent of the tumor process, i.e., the stage of the disease. Determining the stage of CCU is based on the clinical classification of the International Federation of Gynecology and Obstetrics (FIGO) (2009) and has a number of substantial limitations in evaluating parametrial invasion, tumor spread to the pelvic wall, and involvement of regional lymph nodes and in determining the true tumor sizes. Magnetic resonance imaging (MRI) is now the method of choice in staging invasive CCU. Multiparameter MRI will be able to enhance the efficiency of diagnosing microinvasive CCU as well (FIGO 2009), to plan surgical and/or chemoradiation treatment, to evaluate its efficiency, and to diagnose locally recurrent CCU.

  1. [Usefulness of computed tomography and magnetic resonance in the preoperative diagnosis for hyperparathyroidism].

    PubMed

    Pino Rivero, V; Pantoja Hernández, C G; González Palomino, A; Trinidad Ruíz, G; Marcos García, M; Keituqwa Yáñez, T; Pardo Romero, G; Blasco Huelva, A

    2005-01-01

    Sonnography and Tc-99m sestamibi scintigraphy are the most requested preoperative imaging tests nowdays in the surgery of hyperparathyroidism. The aim of our article is to know if Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) are useful as a location study and in which cases it would be more justified to ask these radiologic techniques. For that we report our results with 29 patients at all diagnosed as hyperparathyroidism (26 primary forms and 3 secondary ones) and operated by our E.N.T. Department later. On 20 of them a cervical CT was asked before the parathyroidectomy and on the rest 9, a MRI with sensitivities of 65% and 88.9% respectively. We think both complementary explorations must not be solicited by routine but they can represent a help in the cases in that sonnography and scintigraphy are not able to show the possible adenoma or hiperplasia, particularly in recurrent hyperparathyroidisms, reinterventions or suspect of parathyroid glands in an atypical location.

  2. Cardiovascular imaging in the diagnosis and monitoring of cardiotoxicity: cardiovascular magnetic resonance and nuclear cardiology.

    PubMed

    Pepe, Alessia; Pizzino, Fausto; Gargiulo, Paola; Perrone-Filardi, Pasquale; Cadeddu, Christian; Mele, Donato; Monte, Ines; Novo, Giuseppina; Zito, Concetta; Di Bella, Gianluca

    2016-05-01

    Chemotherapy-induced cardiotoxicity (CTX) is a determining factor for the quality of life and mortality of patients administered potentially cardiotoxic drugs and in long-term cancer survivors. Therefore, prevention and early detection of CTX are highly desirable, as is the exploration of alternative therapeutic strategies and/or the proposal of potentially cardioprotective treatments. In recent years, cardiovascular imaging has acquired a pivotal role in this setting. Although echocardiography remains the diagnostic method most used to monitor cancer patients, the need for more reliable, reproducible and accurate detection of early chemotherapy-induced CTX has encouraged the introduction of second-line advanced imaging modalities, such as cardiac magnetic resonance (CMR) and nuclear techniques, into the clinical setting. This review of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to afford an overview of the most important findings from the literature about the role of CMR and nuclear techniques in the management of chemotherapy-treated patients, describe conventional and new parameters for detecting CTX from both diagnostic and prognostic perspectives and provide integrated insight into the role of CMR and nuclear techniques compared with other imaging tools and versus the positions of the most important international societies.

  3. Magnetic resonance imaging: A new tool for diagnosis of acute ischemic colitis?

    PubMed Central

    Iacobellis, Francesca; Berritto, Daniela; Somma, Francesco; Cavaliere, Carlo; Corona, Marco; Cozzolino, Santolo; Fulciniti, Franco; Cappabianca, Salvatore; Rotondo, Antonio; Grassi, Roberto

    2012-01-01

    AIM: To define the evolution of ischemic lesions with 7T magnetic resonance imaging (7T-MRI) in an animal model of acute colonic ischemia. METHODS: Adult Sprague-Dawley rats were divided into two groups. Group I underwent inferior mesenteric artery (IMA) ligation followed by macroscopic observations and histological analysis. In group II, 7T-MRI was performed before and after IMA ligation and followed by histological analysis. RESULTS: Morphological alterations started to develop 1 h after IMA ligation, when pale areas became evident in the splenic flexure mesentery and progressively worsened up to 8 h thereafter, when the mesentery was less pale, and the splenic flexure loop appeared very dark. The 7T-MRI results reflected these alterations, showing a hyperintense signal in both the intraperitoneal space and the colonic loop wall 1 h after IMA ligation; the latter progressively increased to demonstrate a reduction in the colonic loop lumen at 6 h. Eight hours after IMA ligation, MRI showed a persistent colonic mural hyperintensity associated with a reduction in peritoneal free fluid. The 7T-MRI findings were correlated with histological alterations, varying from an attenuated epithelium with glandular apex lesions at 1 h to coagulative necrosis and loss of the surface epithelium detected 8 h after IMA ligation. CONCLUSION: MRI may be used as a substitute for invasive procedures in diagnosing and grading acute ischemic colitis, allowing for the early identification of pathological findings. PMID:22509081

  4. Magnetic resonance diagnosis of tarsal tunnel syndrome due to flexor digitorum accessorius longus and peroneocalcaneus internus muscles.

    PubMed

    Duran-Stanton, Amelia M; Bui-Mansfield, Liem T

    2010-01-01

    Anomalous muscles of the ankle are common. Although they are often asymptomatic, they can sometimes cause tarsal tunnel syndrome. We report a case of tarsal tunnel syndrome due to flexor digitorum accessorius longus and peroneocalcaneus internus muscles diagnosed on magnetic resonance imaging. Recognition of the most common accessory muscles of the ankle on magnetic resonance imaging and tarsal tunnel syndrome are also reviewed.

  5. Prediction and diagnosis of renal cell carcinoma using nuclear magnetic resonance-based serum metabolomics and self-organizing maps

    PubMed Central

    Zheng, Hong; Ji, Jiansong; Zhao, Liangcai; Chen, Minjiang; Shi, An; Pan, Linlin; Huang, Yiran; Zhang, Huajie; Dong, Baijun; Gao, Hongchang

    2016-01-01

    Diagnosis of renal cell carcinoma (RCC) at an early stage is challenging, but it provides the best chance for cure. We aimed to develop a predictive diagnostic method for early-stage RCC based on a biomarker cluster using nuclear magnetic resonance (NMR)-based serum metabolomics and self-organizing maps (SOMs). We trained and validated the SOM model using serum metabolome data from 104 participants, including healthy individuals and early-stage RCC patients. To assess the predictive capability of the model, we analyzed an independent cohort of 22 subjects. We then used our method to evaluate changes in the metabolic patterns of 23 RCC patients before and after nephrectomy. A biomarker cluster of 7 metabolites (alanine, creatine, choline, isoleucine, lactate, leucine, and valine) was identified for the early diagnosis of RCC. The trained SOM model using a biomarker cluster was able to classify 22 test subjects into the appropriate categories. Following nephrectomy, all RCC patients were classified as healthy, which was indicative of metabolic recovery. But using a diagnostic criterion of 0.80, only 3 of the 23 subjects could not be confidently assessed as metabolically recovered after nephrectomy. We successfully followed-up 17 RCC patients for 8 years post-nephrectomy. Eleven of these patients who diagnosed as metabolic recovery remained healthy after 8 years. Our data suggest that a SOM model using a biomarker cluster from serum metabolome can accurately predict early RCC diagnosis and can be used to evaluate postoperative metabolic recovery. PMID:27463020

  6. Myocardial perfusion cardiac magnetic resonance for the diagnosis of coronary artery disease: do we need rest images?

    PubMed

    Krittayaphong, Rungroj; Boonyasirinant, Thananya; Saiviroonporn, Pairash; Nakyen, Supaporn; Thanapiboonpol, Prajak; Yindeengam, Ahthit; Udompunturak, Suthipol

    2009-04-01

    Adenosine stress cardiovascular magnetic resonance (CMR) has been reported to be useful for the diagnosis of coronary artery disease (CAD). Most studies use rest and stress perfusion images. The objectives of this study were to determine (Barkhausen et al. in J Magn Reson Imaging 19(6):750-757, 1) the accuracy of visual assessment and myocardial perfusion reserve index (MPRI) in the diagnosis of CAD and (Rieber et al. in Fur Heart J 27(12):1465-1471, 2) the accuracy of analysis based on rest-stress and stress images. We enrolled patients with suspected CAD and referred them for coronary angiography (CAG). All the patients underwent adenosine stress CMR before CAG. Rest and stress perfusion images were analyzed by calculation of MPRI and visual assessment separately. Visual assessment was performed separately by using rest and stress images and by using only stress images. CAG was considered the gold standard. Sensitivity, specificity, and accuracy of both methods were calculated and compared. A total of 66 patients (mean age, 61.3 +/- 11.7 years) were studied. Thirty-eight patients (57.6%) were diagnosed with CAD. The sensitivity and specificity for the diagnosis of CAD (> or =50% stenosis) were 89.5 and 78.6% for MPRI, 76.3 and 75% for stress-rest visual method, and 86.8 and 75% for stress visual method, respectively. CMR perfusion had a relatively lower accuracy in patients with left ventricular systolic dysfunction, high left ventricular mass, or presence of late gadolinium enhancement than in patients without those CMR findings. Visual assessment of stress image of CMR perfusion is accurate and comparable to MPRI for the detection of CAD.

  7. Diagnosis of pulmonary hypertension from magnetic resonance imaging–based computational models and decision tree analysis

    PubMed Central

    Swift, Andrew J.; Capener, David; Kiely, David; Hose, Rod; Wild, Jim M.

    2016-01-01

    Abstract Accurately identifying patients with pulmonary hypertension (PH) using noninvasive methods is challenging, and right heart catheterization (RHC) is the gold standard. Magnetic resonance imaging (MRI) has been proposed as an alternative to echocardiography and RHC in the assessment of cardiac function and pulmonary hemodynamics in patients with suspected PH. The aim of this study was to assess whether machine learning using computational modeling techniques and image-based metrics of PH can improve the diagnostic accuracy of MRI in PH. Seventy-two patients with suspected PH attending a referral center underwent RHC and MRI within 48 hours. Fifty-seven patients were diagnosed with PH, and 15 had no PH. A number of functional and structural cardiac and cardiovascular markers derived from 2 mathematical models and also solely from MRI of the main pulmonary artery and heart were integrated into a classification algorithm to investigate the diagnostic utility of the combination of the individual markers. A physiological marker based on the quantification of wave reflection in the pulmonary artery was shown to perform best individually, but optimal diagnostic performance was found by the combination of several image-based markers. Classifier results, validated using leave-one-out cross validation, demonstrated that combining computation-derived metrics reflecting hemodynamic changes in the pulmonary vasculature with measurement of right ventricular morphology and function, in a decision support algorithm, provides a method to noninvasively diagnose PH with high accuracy (92%). The high diagnostic accuracy of these MRI-based model parameters may reduce the need for RHC in patients with suspected PH. PMID:27252844

  8. Heterotopic ossification of the knee joint in intensive care unit patients: early diagnosis with magnetic resonance imaging

    PubMed Central

    Argyropoulou, Maria I; Kostandi, Eleonora; Kosta, Paraskevi; Zikou, Anastasia K; Kastani, Dimitra; Galiatsou, Efi; Kitsakos, Athanassios; Nakos, George

    2006-01-01

    Introduction Heterotopic ossification (HO) is the formation of bone in soft tissues. The purpose of the present study was to evaluate the magnetic resonance imaging (MRI) findings on clinical suspicion of HO in the knee joint of patients hospitalised in the intensive care unit (ICU). Methods This was a case series of 11 patients requiring prolonged ventilation in the ICU who had the following diagnoses: head trauma (nine), necrotising pancreatitis (one), and fat embolism (one). On clinical suspicion of HO, x-rays and MRI of the knee joint were performed. Follow-up x-rays and MRI were also performed. Results First x-rays were negative, whereas MRI (20.2 ± 6.6 days after admission) showed joint effusion and in fast spin-echo short time inversion-recovery (STIR) images a 'lacy pattern' of the muscles vastus lateralis and medialis. The innermost part of the vastus medialis exhibited homogeneous high signal. Contrast-enhanced fat-suppressed T1-weighted images also showed a 'lacy pattern.' On follow-up (41.4 ± 6.6 days after admission), STIR and contrast-enhanced T1-weighted images depicted heterogeneous high signal and heterogeneous enhancement, respectively, at the innermost part of the vastus medialis, whereas x-rays revealed a calcified mass in the same position. Overall, positive MRI findings appeared simultaneously with clinical signs (1.4 ± 1.2 days following clinical diagnosis) whereas x-ray diagnosis was evident at 23 ± 4.3 days (p = 0.002). Conclusion MRI of the knee performed on clinical suspicion shows a distinct imaging pattern confirming the diagnosis of HO earlier than other methods. MRI diagnosis may have implications for early intervention in the development of HO. PMID:17074077

  9. Cardiovascular Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Pelc, Norbert

    2000-03-01

    Cardiovascular diseases are a major source of morbidity and mortality in the United States. Early detection of disease can often be used to improved outcomes, either through direct interventions (e.g. surgical corrections) or by causing the patient to modify his or her behavior (e.g. smoking cessation or dietary changes). Ideally, the detection process should be noninvasive (i.e. it should not be associated with significant risk). Magnetic Resonance Imaging (MRI) refers to the formation of images by localizing NMR signals, typically from protons in the body. As in other applications of NMR, a homogeneous static magnetic field ( ~0.5 to 4 T) is used to create ``longitudinal" magnetization. A magnetic field rotating at the Larmor frequency (proportional to the static field) excites spins, converting longitudinal magnetization to ``transverse" magnetization and generating a signal. Localization is performed using pulsed gradients in the static field. MRI can produce images of 2-D slices, 3-D volumes, time-resolved images of pseudo-periodic phenomena such as heart function, and even real-time imaging. It is also possible to acquire spatially localized NMR spectra. MRI has a number of advantages, but perhaps the most fundamental is the richness of the contrast mechanisms. Tissues can be differentiated by differences in proton density, NMR properties, and even flow or motion. We also have the ability to introduce substances that alter NMR signals. These contrast agents can be used to enhance vascular structures and measure perfusion. Cardiovascular MRI allows the reliable diagnosis of important conditions. It is possible to image the blood vessel tree, quantitate flow and perfusion, and image cardiac contraction. Fundamentally, the power of MRI as a diagnostic tool stems from the richness of the contrast mechanisms and the flexibility in control of imaging parameters.

  10. Prenatal diagnosis of thoracic ectopia cordis by real-time fetal cardiac magnetic resonance imaging and by echocardiography.

    PubMed

    Moniotte, Stéphane; Powell, Andrew J; Barnewolt, Carol E; Annese, David; Geva, Tal

    2008-01-01

    Ectopia cordis is a rare congenital defect commonly associated with intra- and extra-cardiac anomalies. This report highlights the complimentary use of echocardiography and cardiac magnetic resonance imaging for detailed prenatal characterization of the anomaly at 23-week gestation.

  11. Strongly magnetic iron nanoparticles improve the diagnosis of small tumours in the reticuloendothelial system by magnetic resonance imaging.

    PubMed

    Ferguson, Peter M; Feindel, Kirk W; Slocombe, Angela; MacKay, Matthew; Wignall, Trudy; Delahunt, Brett; Tilley, Richard D; Hermans, Ian F

    2013-01-01

    Despite advances in non-invasive medical imaging, accurate nodal staging of malignancy continues to rely on surgery. Superparamagnetic iron oxide nanoparticles (IONP) with lymphotropic qualities have shown some promise as contrast agents for MRI of the lymph nodes, but recent large-scale studies failed to show consistent detection of tumours below 5 mm. Herein we compare imaging of splenic and lymph node tissue using iron/iron oxide core/shell nanoparticles (Fe NP) that have superior magnetic qualities to IONP, to determine whether improved negative contrast in T(2)-weighted MRI can enhance the diagnosis of small tumours in the reticuloendothelial system. To provide an in vivo pre-clinical model of human lymph node micrometastases, breast cancer cells were injected into the spleens of mice, providing localised areas of tumour growth. MR images of groups of tumour-bearing and sham-treated animals were generated using a 1.5 T imaging system and analysed by two independent, blinded radiologists. Fe NP improved the sensitivity and specificity of MRI when compared to IONP, enabling accurate detection of tumours as small as 1-3 mm. The use of Fe NP as contrast agents have the potential to improve the diagnostic accuracy of MRI in cancer patients, leading to more rapid and effective treatment.

  12. Diagnosis of Paracardiac Castleman Disease by Dynamic Gadolinium-Enhanced First Pass Perfusion Magnetic Resonance Imaging

    PubMed Central

    Crean, Andrew; Paul, Narinder; Merchant, Naeem; Singer, Lianne; Provost, Yves

    2008-01-01

    Summary Castleman disease is an uncommon disorder affecting the lymphatic system and is characterised by atypical lymphocyte proliferation. The usual clinical presentation is of a solitary mass lesion, frequently within the thorax. A number of different imaging findings have been reported on CT and MRI. We present a case of paracardiac Castleman disease where the diagnosis was suggested by dramatic enhancement of the tumour mass during a dynamic MR perfusion sequence. To our knowledge this is the first report of the use of a first pass bolus tracking technique in the diagnosis of Castleman disease. PMID:24179362

  13. Magnetic resonance sees lesions of multiple sclerosis

    SciTech Connect

    Ziporyn, T.

    1985-02-15

    The value of nuclear magnetic resonance imaging in the diagnosis and quantitation of the progression of multiple sclerosis is discussed. Magnetic resonance imaging generates images that reflect differential density and velocity of hydrogen nuclei between cerebral gray and white matter, as well as between white matter and pathological lesions of the disease.

  14. Clinically Practical Magnetic Resonance Protocol for Improved Specifically in Breast Cancer Diagnosis

    DTIC Science & Technology

    2006-06-01

    ASSESSMENT Not applicable 12. CRITERIA FOR REMOVAL FROM STUDY If a subject decides to discontinue exam there will be no penalty or loss of...patches may cause skin burns during MRI examination. If you wear them, you will be asked to remove them before undergoing the study. Due to high...Watches • Keys • Dentures or partial plates • Hearing aids • Transdermal patches Magnetic waves can also erase the code on bankcards and

  15. [Role of magnetic resonance imaging in the diagnosis of juvenile dermato-myositis and polymyositis in Chinese children].

    PubMed

    Lai, J M; Wu, F Q; Zhou, Z X; Yuan, X Y; Su, G X; Li, S N; Yan, Y C; Zhu, J; Kang, M

    2016-10-02

    Objective: To evaluate the utility of magnetic resonance imaging (MRI) in diagnosis of juvenile dermatomyositis and polymyositis (JDM-PM) in children. Method: Fifty-four patients with JDM-PM in the active stage were enrolled in the study group. Twelve patients with benign acute childhood myositis and forty patients with juvenile idiopathic arthritis (JIA) complicated with myositis were enrolled as controls. MRI imaging of thighs was performed in all patients, fast spin echo T1WI, T2WI, and STIR were obtained in all patients.Muscle biopsy was performed in 41/54 patients with JDM-PM. We compared the value of MRI in diagnosis of JDM-PM with muscle biopsy, electromyography and serum aspartate transaminase (AST), alanine transaminase (ALT), creatine kinase (CK), isoenzyme of creatine kinase (CKMB), lactate dehydrogenase (LDH), hydroxybutyrate dehydrogenase (HBDH) levels. Continuous normally distributed variables were reported as means and continuous non-normally distributed variables as median. Chi-square test and Fisher exact test were used to test differences between MRI and other categorical variables. Result: A total of 54 patients were included. Twenty-seven patients were male and the others were female. Average age of the patients was (7.1±3.5) years (2-13 years); 45(83%) paitests were JDM cases and 9(17%) patients had JPM. All patients had MRI examination. Of the 54 patients, 53 had multiple myositis; 10 out of 50 (19%) patients received second MRI after treatment, 6 out of 10 patients had normal findings, 4 patients showed obviously improved images; 41 out of 54 patients underwent muscle biopsy; 22 out of 41 patients had inflammatory cells infiltration and muscle fiber degeneration. The results of the muscle enzyme tests are as follows: 27 (50%) patients had elevated AST, 24 (44%) patients had elevated ALT, 22 (41%) patients had elevated CK, 18(33%) patients had elevated CKMB, and LDH rose in 30 (56%) patients, HBDH rose in 28(52%) patients. These results

  16. The performance of transrectal ultrasound in the diagnosis of seminal vesicle defects: a comparison with magnetic resonance imaging

    PubMed Central

    Chen, Xu; Wang, Hua; Wu, Rong-Pei; Liang, Hui; Mao, Xiao-Peng; Mao, Cheng-Qiang; Zhu, Hong-Zhang; Qiu, Shao-Peng; Wang, Dao-Hu

    2014-01-01

    Obstructive azoospermia (OA) is one of the most common causes of male infertility. Transrectal ultrasound (TRUS) has been used to diagnose OA for many years. From 2009 to 2013, we evaluated a prospective cohort of 1249 patients with suspected OA using TRUS. It was found that dilation of the ejaculatory duct (ED) (29.9%, 374/1249) was the most common cause of OA, followed by seminal vesicle (SV) abnormalities (28.5%, 356/1249). A total of 237 patients were diagnosed with congenital defects (agenesis and/or hypoplasia) of the SV, constituting more than half of the cases of SV disease in OA (19.0%, 237/1249). In contrast to ED, congenital defects of the SV could not be corrected with surgical treatment. Therefore, it is meaningful to compare TRUS and magnetic resonance imaging (MRI) for accurate diagnosis of SV defects. Among our patients, 30 with agenesis or/and hypoplasia of the SV on TRUS were further evaluated using pelvic MRI within 2 years, with the objective of verifying the TRUS results. The concordance rate for diagnosing congenital defects of the SV was 73.3% (22/30). We concluded that TRUS is a reliable and convenient method for diagnosing agenesis or hypoplasia of the SV in OA patients with a high concordance with MRI while MRI is useful in patients with inconclusive TRUS findings. PMID:25337847

  17. Application of proton magnetic resonance spectroscopy and computerized tomography in the diagnosis and treatment of nonalcoholic fatty liver disease.

    PubMed

    Wang, Nan; Dong, Hui; Wei, Shichao; Lu, Fuer

    2008-06-01

    In order to investigate the application of proton magnetic resonance spectroscopy ((1)H-MRS) and computerized tomography (CT) in the quantitative diagnosis of nonalcoholic fatty liver disease (NAFLD) and evaluation of therapeutic effects, 22 patients with NAFLD were selected according to the Chinese Medical Association's (CMA) standard of the NAFLD in comparison with 20 healthy volunteers (as control group). Blood samples for biochemistry were collected. The severity of hepatosteatosis was evaluated by (1)H-MRS scan and CT scan of liver. The intrahepatic content of lipid (IHCL) and CT value ratio of liver to spleen were calculated. The patients in NAFLD group were treated with Ganzhixiao Capsule for 8 weeks. The changes in IHCL and CT value ratio of liver to spleen were observed before and after treatment. In NAFLD group serum ALT, TG, IHCL calculated by (1)HMRS were increased and CT value ratio of liver to spleen decreased significantly as compared with control group. After treatment for 8 weeks serum ALT, TG, IHCL were decreased significantly, while CT value ratio of liver to spleen increased significantly in NAFLD group. It was suggested that IHCL could be measured precisely by (1)HMRS. NAFLD was treated effectively by Ganzhixiao capsule.

  18. Magnetic resonance imaging of the cirrhotic liver: diagnosis of hepatocellular carcinoma and evaluation of response to treatment - Part 1

    PubMed Central

    Ramalho, Miguel; Matos, António P.; AlObaidy, Mamdoh; Velloni, Fernanda; Altun, Ersan; Semelka, Richard C.

    2017-01-01

    Magnetic resonance imaging (MRI) is the modern gold standard for the noninvasive evaluation of the cirrhotic liver. The combination of arterial phase hyperenhancement and delayed wash-out allows a definitive diagnosis of hepatocellular carcinoma (HCC) in patients with liver cirrhosis or chronic liver disease, without the requirement for confirmatory biopsy. That pattern is highly specific and has been endorsed in Western and Asian diagnostic guidelines. However, the sensitivity of the combination is relatively low for small HCCs. In this two-part review paper, we will address MRI of the cirrhotic liver. In this first part, we provide a brief background on liver cirrhosis and HCC, followed by descriptions of imaging surveillance of liver cirrhosis and the diagnostic performance of the different imaging modalities used in clinical settings. We then describe some of the requirements for the basic MRI technique, as well as the standard MRI protocol, and provide a detailed description of the appearance of various types of hepatocellular nodules encountered in the setting of the carcinogenic pathway in the cirrhotic liver, ranging from regenerative nodules to HCC. PMID:28298731

  19. Problems with diagnosis by fluid-attenuated inversion recovery magnetic resonance imaging in patients with acute aneurysmal subarachnoid hemorrhage.

    PubMed

    Shimoda, Masami; Hoshikawa, Kaori; Shiramizu, Hideki; Oda, Shinri; Matsumae, Mitsunori

    2010-01-01

    The diagnostic efficacy of fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging and computed tomography (CT) for acute subarachnoid hemorrhage (SAH) were compared and the problems with diagnosis were investigated in 81 patients with aneurysmal SAH within 24 hours after onset who underwent FLAIR imaging and CT on admission. The number of hematomas in the cisterns and ventricles were evaluated by clot scores. In addition, the frequency of undetected hematomas was calculated for the cisterns and ventricles. Clot scores were significantly higher for FLAIR imaging than for CT in the lateral sylvian, quadrigeminal, and convexity cisterns. On the other hand, clot scores were significantly higher for CT than for FLAIR imaging in the interhemispheric and medial sylvian cisterns. The overall frequency of undetected SAH was 2% for FLAIR imaging and 14% for CT. With the exception of the interhemispheric and medial sylvian cisterns, the frequency of undetected SAH was higher for CT than for FLAIR imaging. In this study, FLAIR imaging was more sensitive than CT for the detection of acute SAH within 24 hours after onset. However, the diagnostic efficacy of FLAIR imaging was reduced in comparatively tight cisterns.

  20. Investigation of magnetic field enriched surface enhanced resonance Raman scattering performance using Fe3O4@Ag nanoparticles for malaria diagnosis

    NASA Astrophysics Data System (ADS)

    Yuen, Clement; Liu, Quan

    2014-03-01

    Recently, we have demonstrated the magnetic field-enriched surface-enhanced resonance Raman spectroscopy (SERRS) of β-hematin by using nanoparticles with iron oxide core and silver shell (Fe3O4@Ag) for the potential application in the early malaria diagnosis. In this study, we investigate the dependence of the magnetic field-enriched SERRS performance of β-hematin on the different core and shell sizes of the Fe3O4@Ag nanoparticles. We note that the core and shell parameters are critical in the realization of the optimal magnetic field-enrich SERRS β-hematin signal. These results are consistent with our simulations that will guide the optimization of the magnetic SERRS performance for the potential early diagnosis in the malaria disease.

  1. Nuclear magnetic resonance gyroscope

    SciTech Connect

    Grover, B.C.

    1984-02-07

    A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor.

  2. Sacroiliitis at diagnosis of juvenile spondyloarthritis assessed by radiography, magnetic resonance imaging, and clinical examination

    PubMed Central

    Weiss, Pamela F; Xiao, Rui; Biko, David M; Chauvin, Nancy A

    2015-01-01

    Objective We evaluated the prevalence of sacroiliitis at diagnosis of juvenile spondyloarthritis (JSpA) and the accuracy of physical examination and back pain to detect sacroiliitis, using imaging as the reference standard. Methods We performed a prospective cross-sectional study of 40 children with newly diagnosed JSpA and 14 healthy controls. Subjects were assessed using physical examination, anteroposterior pelvic radiograph, and pelvic MRI. Differences in clinical features between those children with and without sacroiliitis were assessed by Fisher’s exact test for categorical variables and Wilcoxon rank sum test for continuous variables. Accuracy of physical examination and back pain for detection of sacroiliitis was determined using MRI as the reference standard. Predicted probability of sacroiliitis was determined using exact multivariate logistic regression. Results Eight (20%) children with JSpA had active sacroiliitis. Of those subjects with active changes on MRI, 7/8 (88%) also had evidence of erosions or sclerosis. Five (13%) children with JSpA and 1 (7%) control had non-periarticular bone marrow edema. Of the subjects with active sacroiliitis only 3 (38%) reported a history of back pain or tenderness on palpation of the sacroiliac joints. The positive and negative predictive values of clinical exam features and back pain for detection of sacroiliitis were low. The estimated probability of having sacroiliitis was 0.84 (95% CI: 0.40–1.00) in HLA-B27+ patients with an elevated CRP. Conclusion Active sacroiliitis by MRI is common at diagnosis in JSpA and is frequently asymptomatic. Children who are HLA-B27+ and have elevated CRP levels have the highest probability of sacroiliitis. PMID:26212574

  3. Diffusion weighted magnetic resonance imaging in the diagnosis of parotid masses. Preliminary results

    PubMed Central

    Yologlu, Zeynel; Aydin, Hasan; Alp, Nalan A.; Aribas, Bilgin K.; Kizilgoz, Volkan; Arda, Kemal

    2016-01-01

    Objective To demonstrate the diagnostic potentials of MRI, diffusion weighted imaging (DWI), and apparent diffusion coefficient (ADC) mapping in the detection of parotid masses correlated to the histopathological results. Methods Study design was retrospective. Fifteen patients with parotid gland masses were included as the study group and contralateral normal parotis glands of same patients were taken as the control group. Patients with bilateral parotid gland tumors were excluded, 7 right-sided and 8 left-sided parotid masses were included in the research. The study took place at the Department of Radiology, Ankara, Turkey, between May 2012 and September 2014. Results Apparent diffusion coefficient measurements of 15 parotis tumors in 1000 and 750 sec/mm2 b-values with comparison to the contralateral normal gland parenchyma were demonstrated. Neurofibromas was predicted as the highest, and lipomas as the lowest ADC values. Pleomorphic adenomas, Warthin’s tumor, and normal parotid parenchyma indicate significant statistical differences from each other on the basis of mean ADC values (p<0.05). Conclusion The DWI and ADC mapping of parotis gland could aid in the differential diagnosis of benign and malignant masses. PMID:27874161

  4. Brainstem tegmental lesions in neonates with hypoxic-ischemic encephalopathy: Magnetic resonance diagnosis and clinical outcome

    PubMed Central

    Quattrocchi, Carlo Cosimo; Fariello, Giuseppe; Longo, Daniela

    2016-01-01

    Lesions of the brainstem have been reported in the clinical scenarios of hypoxic-ischemic encephalopathy (HIE), although the prevalence of these lesions is probably underestimated. Neuropathologic studies have demonstrated brainstem involvement in severely asphyxiated infants as an indicator of poor outcome. Among survivors to HIE, the most frequent clinical complaints that may be predicted by brainstem lesions include feeding problems, speech, language and communication problems and visual impairments. Clinical series, including vascular and metabolic etiologies, have found selective involvement of the brainstem with the demonstration of symmetric bilateral columnar lesions of the tegmentum. The role of brainstem lesions in HIE is currently a matter of debate, especially when tegmental lesions are present in the absence of supra-tentorial lesions. Differential diagnosis of tegmental lesions in neonates and infants include congenital metabolic syndromes and drug-related processes. Brainstem injury with the presence of supratentorial lesions is a predictor of poor outcome and high rates of mortality and morbidity. Further investigation will be conducted to identify specific sites of the brainstem that are vulnerable to hypoxic-ischemic and toxic-metabolic insults. PMID:26981220

  5. Gynecologic masses: value of magnetic resonance imaging.

    PubMed

    Hricak, H; Lacey, C; Schriock, E; Fisher, M R; Amparo, E; Dooms, G; Jaffe, R

    1985-09-01

    Forty-two women with gynecologic abnormalities were studied with the use of magnetic resonance imaging. Magnetic resonance imaging correctly assessed the origin of the pelvic mass in all patients. In the evaluation of leiomyoma, magnetic resonance imaging accurately depicted the number, size, and location of the lesion. In the evaluation of endometrial carcinoma, magnetic resonance imaging depicted the location of the lesion, the presence of cervical extension, and the depth of myometrial penetration in the majority of the cases. In the analysis of adnexal cysts, magnetic resonance imaging was sensitive in localizing the lesion and was able to distinguish serous from hemorrhagic fluid. This preliminary report indicates that magnetic resonance imaging may become a valuable imaging modality in the diagnosis of gynecologic abnormalities.

  6. Magnetic Resonance Imaging in Differentatial Diagnosis of Pyogenic Spondylodiscitis and Tuberculous Spondylodiscitis

    PubMed Central

    Frel, Małgorzata; Białecki, Jerzy; Wieczorek, Janusz; Paluch, Łukasz; Dąbrowska-Thing, Agnieszka; Walecki, Jerzy

    2017-01-01

    Summary Background Infectious spondylodiscitis is characterized by the involvement of two adjacent vertebrae and the intervening disc. Incidence rate of the disease is estimated at 0.4–2 cases per 100000 per year. Staphylococcus aureus is the most common infectious agent causing pyogenic spondylodiscitis. Non-pyogenic infections of the spine are most frequently caused by Mycobacterium tuberculosis, and fungi. Clinical symptoms are nonspecific. Early diagnosis and appropriate treatment can prevent unfavorable irreversible sequela for the patient. Significant developments in techniques of imaging of pathological tissues raised expectations among the clinicians regarding possibility to distinguish between tuberculous spondylodiscitis and pyogenic spondylodiscitis on MR images. The aim of this study was to identify and differentiate between features of tuberculous and pyogenic spondylodiscitis on MR images. Material/Methods We performed retrospective analysis of MR images obtained from 34 patients with confirmed spondylodiscitis (18 with pyogenic spondylodiscitis, and 16 with tuberculous spondylodiscitis). Data acquisition was performed using 1.5 T MRI scanners where images were obtained using similar protocols. T2 TIRM and T1-weighted images with and without contrast enhancement were subject to assessment in coronal, axial and sagittal planes. Results Characteristic features of pyogenic spondylodiscitis include: involvement of the lumbar spine, ill-defined paraspinal abnormal contrast enhancement, diffuse/homogeneous contrast enhancement of vertebral bodies, low-grade destruction of vertebral bodies, hyperintense/homogeneous signal from the vertebral bodies on T2 TIRM images. Prevailing features of tuberculous spondylodiscitis included: involvement of the thoracic spine, involvement of 2 or more adjacent vertebral bodies, severe destruction of the vertebral body, focal/heterogeneous contrast enhancement of vertebral bodies, heterogeneous signal from the vertebral

  7. Optimization of Fe3O4@Ag nanoshells in magnetic field-enriched surface-enhanced resonance Raman scattering for malaria diagnosis.

    PubMed

    Yuen, Clement; Liu, Quan

    2013-11-07

    The great potential of magnetic field enriched surface enhanced resonance Raman spectroscopy (SERRS) for early malaria diagnosis has been demonstrated previously. This technique is able to detect β-hematin, which is equivalent to a malaria biomarker (hemozoin) in Raman features, at a concentration of 5 nM. In this study, we present the optimization of nanoparticles used in the magnetic field enriched SERRS by tuning the core size and shell thickness of nanoparticles with an iron oxide core and a silver shell (Fe3O4@Ag). The discrete dipole approximation (DDA) model was introduced to investigate the localized electromagnetic field distributions and extinction efficiencies of the aggregate of Fe3O4@Ag and β-hematin, in correlation with their magnetic field enriched SERRS performance. We find that the optimal core-shell size of Fe3O4@Ag leading to the effective aggregation of Fe3O4@Ag and β-hematin under an external magnetic field with superior extinction efficiencies is the key to realize highly augmented Raman signals in this strategy. Furthermore, it is noted that the optimized result differs from the case without the external magnetic field to that with the external magnetic field. Therefore, this work demonstrates experimentally and theoretically the potential of tuning the core-shell Fe3O4@Ag for achieving the efficient magnetic field-enriched SERRS detection of β-hematin for early malaria diagnosis.

  8. Magnetic resonance imaging of the maxilla and mandible: signal characteristics and features in the differential diagnosis of common lesions.

    PubMed

    Mosier, Kristine M

    2015-02-01

    The maxilla and mandible are among the most difficult areas of the body to image with magnetic resonance techniques owing to the geometry of the jaws as well as the frequent susceptibility artifacts from dental restorations or appliances. This chapter briefly reviews the essentials of imaging techniques and basic anatomy and discusses the most common inflammatory conditions, benign and malignant lesions of the jaws, and temporomandibular joint. This review emphasizes and illustrates specific magnetic resonance features that facilitate characterization and diagnostic differentiation of these lesions. As the focus of this review is on the differentiation of infection and benign and malignant disease, a discussion of internal derangements and associated inflammatory disorders of the temporomandibular joint is beyond the scope of this review and is not discussed.

  9. Myocardial edema in Takotsubo syndrome mimicking apical hypertrophic cardiomyopathy: An insight into diagnosis by cardiovascular magnetic resonance.

    PubMed

    Izgi, Cemil; Ray, Sanjoy; Nyktari, Evangelia; Alpendurada, Francisco; Lyon, Alexander R; Rathore, Sudhir; Baksi, Arun John

    2015-01-01

    Myocardial edema is one of the characteristic features in the pathogenesis of Takotsubo syndrome. We report a middle aged man who presented with typical clinical and echocardiographic features of apical variant of Takotsubo syndrome. However, a cardiovascular magnetic resonance study performed 10 days after presentation did not show any apical 'ballooning' but revealed features of an apical hypertrophic cardiomyopathy on cine images. Tissue characterization with T2 weighted images proved severe edema as the cause of significantly increased apical wall thickness. A follow-up cardiovascular magnetic resonance study was performed 5 months later which showed that edema, wall thickening and the appearance of apical hypertrophic cardiomyopathy all resolved, confirming Takotsubo syndrome as the cause of the initial appearance. As the affected myocardium most commonly involves the apical segments, an edema induced increase in apical wall thickness may lead to appearances of an apical hypertrophic cardiomyopathy rather than apical ballooning in the acute to subacute phase of Takotsubo syndrome.

  10. Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  11. Single spin magnetic resonance.

    PubMed

    Wrachtrup, Jörg; Finkler, Amit

    2016-08-01

    Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.

  12. Magnetic Resonance Annual, 1985

    SciTech Connect

    Kressel, H.Y.

    1985-01-01

    The inaugural volume of Magnetic Resonance Annual includes reviews of MRI of the posterior fossa, cerebral neoplasms, and the cardiovascular and genitourinary systems. A chapter on contrast materials outlines the mechanisms of paramagnetic contrast enhancement and highlights several promising contrast agents.

  13. Single spin magnetic resonance

    NASA Astrophysics Data System (ADS)

    Wrachtrup, Jörg; Finkler, Amit

    2016-08-01

    Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.

  14. Pediatric Body Magnetic Resonance Imaging.

    PubMed

    Kandasamy, Devasenathipathy; Goyal, Ankur; Sharma, Raju; Gupta, Arun Kumar

    2016-09-01

    Magnetic resonance imaging (MRI) is a radiation-free imaging modality with excellent contrast resolution and multiplanar capabilities. Since ionizing radiation is an important concern in the pediatric population, MRI serves as a useful alternative to computed tomography (CT) and also provides additional clues to diagnosis, not discernible on other investigations. Magnetic resonance cholangiopancreatography (MRCP), urography, angiography, enterography, dynamic multiphasic imaging and diffusion-weighted imaging provide wealth of information. The main limitations include, long scan time, need for sedation/anesthesia, cost and lack of widespread availability. With the emergence of newer sequences and variety of contrast agents, MRI has become a robust modality and may serve as a one-stop shop for both anatomical and functional information.

  15. Diagnosis of Transverse Sinus Hypoplasia in Magnetic Resonance Venography: New Insights Based on Magnetic Resonance Imaging in Combined Dataset of Venous Outflow Impairment Case-Control Studies: Post Hoc Case-Control Study.

    PubMed

    Han, Ke; Chao, A-Ching; Chang, Feng-Chi; Hsu, Hung-Yi; Chung, Chih-Ping; Sheng, Wen-Yung; Chan, Lung; Wu, Jiang; Hu, Han-Hwa

    2016-03-01

    In previous studies of transverse sinus (TS) hypoplasia, discrepancies between TS diameter measured by magnetic resonance venography (MRV) and contrast T1-weighted magnetic resonance (contrast T1) were observed. To investigate these discrepancies, and considering that TS hypoplasia is associated with neurological disorders, we performed a post hoc analysis of prospectively collected data from 3 case-control studies on transient global amnesia (TGA), transient monocular blindness (TMB), and panic disorders while retaining the original inclusion and exclusion criteria. Magnetic resonance (MR) imaging of 131 subjects was reviewed to evaluate TS diameter and the location and degree of venous flow stenosis and obstruction.MRV without contrast revealed that TS hypoplasia was observed in 69 subjects, whom we classified into 2 subgroups according to the concordance with contrast T1 observations: concordance indicated anatomically small TS (30 subjects), and discrepancy indicated that the MRV diagnosis is in fact flow-related and that TS is not anatomically small (39 subjects). The latter subgroup was associated with at least 1 site of venous compression/stenosis in the internal jugular vein (IJV) or the left brachiocephalic vein (BCV) (P < 0.001), which was significantly larger in patients than controls. Compensatory dilatation of contralateral TS diameter was only observed with MRV, not with contrast T1 imaging.The clinical implication of these results is that using MRV only, IJV/BCV compression/stenosis may be misdiagnosed as TS hypoplasia. And contralateral TS have no compensatory dilatation in its diameter in contrast T1 imaging, just compensatory increased flow volume.

  16. Resonant magnetic vortices

    SciTech Connect

    Decanini, Yves; Folacci, Antoine

    2003-04-01

    By using the complex angular momentum method, we provide a semiclassical analysis of electron scattering by a magnetic vortex of Aharonov-Bohm type. Regge poles of the S matrix are associated with surface waves orbiting around the vortex and supported by a magnetic field discontinuity. Rapid variations of sharp characteristic shapes can be observed on scattering cross sections. They correspond to quasibound states which are Breit-Wigner-type resonances associated with surface waves and which can be considered as quantum analogues of acoustic whispering-gallery modes. Such a resonant magnetic vortex could provide a different kind of artificial atom while the semiclassical approach developed here could be profitably extended in various areas of the physics of vortices.

  17. Magnetic resonance imaging of the temporomandibular joint.

    PubMed

    Hayt, M W; Abrahams, J J; Blair, J

    2000-04-01

    The spectrum of disease that affects the temporomandibular joint (TMJ) can be varied. To differentiate among the diseases that cause pain and dysfunction, an intimate knowledge of the anatomy, physiology, and pathology of this region is necessary. Due to the joint's complex anatomy and relationship to the skin, it has been difficult to image in the past. Magnetic resonance imaging is ideally suited for visualizing TMJ because of its superb contrast resolution when imaging soft tissues. Magnetic resonance imaging allows simultaneous bilateral visualization of both joints. The ability to noninvasively resolve anatomic detail can be performed easily and quickly using magnetic resonance imaging. The development of magnetic resonance imaging has greatly aided the diagnosis of TMJ disorders. An understanding of TMJ anatomy and pathogenesis of TMJ pain is crucial for interpretation of magnetic resonance imaging and subsequent treatment.

  18. Magnetic resonance neurography-guided nerve blocks for the diagnosis and treatment of chronic pelvic pain syndrome.

    PubMed

    Fritz, Jan; Chhabra, Avneesh; Wang, Kenneth C; Carrino, John A

    2014-02-01

    Magnetic resonance (MR) neurography - guided nerve blocks and injections describe a techniques for selective percutaneous drug delivery, in which limited MR neurography and interventional MR imaging are used jointly to map and target specific pelvic nerves or muscles, navigate needles to the target, visualize the injected drug and detect spread to confounding structures. The procedures described, specifically include nerve blocks of the obturator nerve, lateral femoral cutaneous nerve, pudendal nerve, posterior femoral cutaneous nerve, sciatic nerve, ganglion impar, sacral spinal nerve, and injection into the piriformis muscle.

  19. Single ectopic ureteral orifice with bilateral duplicated renal collecting systems in an adult girl: Diagnosis by magnetic resonance urography.

    PubMed

    Tang, Min; Wang, Quanrongzi; Liu, Bianjiang; Li, Jie; Lu, Qiang; Song, Ninghong; Wang, Zengjun; Zhang, Wei

    2015-01-01

    Renal duplication accompanied by ureteral ectopia is an uncommon urinary congenital abnormality. We report the case of a 21-year-old girl who suffered from lifelong continuous urinary leakage. She was finally diagnosed with bilateral duplicated collecting systems complicated with right ectopic ureteral orifice - an extremely rare case. The patient underwent ureteric re-implantation for the ectopic side, and her urinary incontinence ceased soon thereafter. In this case, traditional imaging failed to show the exact insertion of an ectopic ureter. However, magnetic resonance urography combined with retrograde intubation radiography successfully depicted the point of ureteric insertion, which may make the diagnostic process accurate and efficient.

  20. Magnetic Resonance Safety

    PubMed Central

    Sammet, Steffen

    2016-01-01

    Magnetic Resonance Imaging (MRI) has a superior soft-tissue contrast compared to other radiological imaging modalities and its physiological and functional applications have led to a significant increase in MRI scans worldwide. A comprehensive MRI safety training to protect patients and other healthcare workers from potential bio-effects and risks of the magnetic fields in an MRI suite is therefore essential. The knowledge of the purpose of safety zones in an MRI suite as well as MRI appropriateness criteria is important for all healthcare professionals who will work in the MRI environment or refer patients for MRI scans. The purpose of this article is to give an overview of current magnetic resonance safety guidelines and discuss the safety risks of magnetic fields in an MRI suite including forces and torque of ferromagnetic objects, tissue heating, peripheral nerve stimulation and hearing damages. MRI safety and compatibility of implanted devices, MRI scans during pregnancy and the potential risks of MRI contrast agents will also be discussed and a comprehensive MRI safety training to avoid fatal accidents in an MRI suite will be presented. PMID:26940331

  1. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    PubMed

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

  2. F-18 fluoride positron emission tomography/computed tomography in the diagnosis of avascular necrosis of the femoral head: Comparison with magnetic resonance imaging

    PubMed Central

    Gayana, Shankaramurthy; Bhattacharya, Anish; Sen, Ramesh Kumar; Singh, Paramjeet; Prakash, Mahesh; Mittal, Bhagwant Rai

    2016-01-01

    Objective: Femoral head avascular necrosis (FHAVN) is one of the increasingly common causes of musculoskeletal disability and poses a major diagnostic and therapeutic challenge. Although radiography, scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been widely used in the diagnosis of FHAVN, positron emission tomography (PET) has recently been evaluated to assess vascularity of the femoral head. In this study, the authors compared F-18 fluoride PET/CT with MRI in the initial diagnosis of FHAVN. Patients and Methods: We prospectively studied 51 consecutive patients with a high clinical suspicion of FHAVN. All patients underwent MRI and F-18 fluoride PET/CT, the time interval between the two scans being 4–10 (mean 8) days. Two nuclear medicine physicians blinded to the MRI report read the PET/CT scans. Clinical assessment was also done. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up. Results: A final diagnosis of avascular necrosis (AVN) was made in 40 patients. MRI was 96.5% sensitive, 100% specific, and 98.03% accurate while PET/CT was 100% sensitive, specific, and accurate in diagnosing FHAVN. The agreement between the two imaging modalities for the diagnosis of AVN was 96.07%. Conclusion: F-18 fluoride PET/CT showed good agreement with MRI in the initial diagnosis of FHAVN and can be better than MRI in detecting early disease. PMID:26917886

  3. Magnetic Resonance Facility (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  4. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Griffith, Robert; Larsen, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, design, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  5. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation is concluding the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, and design basics of the NMRG including an overview of the NSD designs developed and demonstrated in the DARPA gyro development program. General performance results from phases 3 and 4 will also be presented.

  6. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  7. The potential of 3T high-resolution magnetic resonance imaging for diagnosis, staging, and follow-up of retinoblastoma.

    PubMed

    de Jong, Marcus C; de Graaf, Pim; Brisse, Hervé J; Galluzzi, Paolo; Göricke, Sophia L; Moll, Annette C; Munier, Francis L; Popovic, Maja Beck; Moulin, Alexandre P; Binaghi, Stefano; Castelijns, Jonas A; Maeder, Philippe

    2015-01-01

    We demonstrate the value of high-resolution magnetic resonance imaging (MRI) in diagnosing, staging, and follow-up of retinoblastoma during eye-saving treatment. We have included informative retinoblastoma cases scanned on a 3T MRI system from a retrospective retinoblastoma cohort from 2009 through 2013. We show that high-resolution MRI has the potential to detect small intraocular seeds, hemorrhage, and metastatic risk factors not visible with fundoscopy (e.g., optic nerve invasion and choroidal invasion), and treatment response. Unfortunately, however, the diagnostic accuracy of high-resolution MRI is not perfect, especially for subtle intraocular seeds or minimal postlaminar optic nerve invasion. The most important application of MRI is the detection of metastatic risk factors, as these cannot be found by fundoscopy and ultrasound.

  8. Diagnosis of temporomandibular dysfunction syndrome--image quality at 1.5 and 3.0 Tesla magnetic resonance imaging.

    PubMed

    Schmid-Schwap, Martina; Drahanowsky, Wolfgang; Bristela, Margit; Kundi, Michael; Piehslinger, Eva; Robinson, Soraya

    2009-05-01

    The purpose of this study was to examine the differences in expert ratings of quality of magnetic resonance images (MRI) of the temporomandibular joint in 24 patients with suspected anterior disc displacement examined in randomized order at 1.5 and 3.0 T. Parasagittal (closed and opened mouth) and paracoronal sections were performed with a surface coil. Two experienced examiners blinded to patient status and type of MRI diagnosed the images according to position of condyle, position and changes in the signal, and disc shape. In addition, perceptibility of position and disc shape were assessed. A highly significant difference in the perceptibility of disc shape (P < 0.001) and position (P < 0.001) was obtained. With comparable examination sequences and identical resolution, the 3.0 T MRI of the temporomandibular joint increases the perceptibility of joint structures.

  9. Prenatal diagnosis of a patent urachus cyst with the use of 2D, 3D, 4D ultrasound and fetal magnetic resonance imaging.

    PubMed

    Fuchs, F; Picone, O; Levaillant, J M; Mabille, M; Mas, A E; Frydman, R; Senat, M V

    2008-01-01

    Patent urachus cyst is a rare umbilical anomaly, which is poorly detected prenatally and frequently confounded with pseudo bladder exstrophy or omphalocele. A 27-year-old woman was referred to our prenatal diagnosis centre at 18 weeks of gestation after diagnosis of a megabladder and 2 umbilical cord cysts. Subsequent 2D, 3D and 4D ultrasound examinations and fetal magnetic resonance imaging (MRI) revealed a typical umbilical cyst and an extra-abdominal cyst, communicating with the vertex of the fetal bladder through a small channel that increased in size when the fetus voided urine. Termination of pregnancy occured at 31 weeks because of associated cerebral septal agenesis, and autopsy confirmed the prenatal diagnosis of urachus cyst. Few cases of urachus cyst diagnosed prenatally are reported in literature, but none were associated with other extra-abdominal disorders and none used 3D, 4D and fetal MRI. Our case illustrated the efficiency in prenatal diagnosis of 3D and 4D ultrasound examinations. This could help pediatrician surgeons to explain to a couple about neonatal surgical repair and plastic reconstruction in the prenatal period.

  10. nuclear magnetic resonance gyroscope

    SciTech Connect

    Karwacki, F. A.; Griffin, J.

    1985-04-02

    A nuclear magnetic resonance gyroscope which derives angular rotation thereof from the phases of precessing nuclear moments utilizes a single-resonance cell situated in the center of a uniform DC magnetic field. The field is generated by current flow through a circular array of coils between parallel plates. It also utilizes a pump and read-out beam and associated electronics for signal processing and control. Encapsulated in the cell for sensing rotation are odd isotopes of Mercury Hg/sup 199/ and Hg/sup 201/. Unpolarized intensity modulated light from a pump lamp is directed by lenses to a linear polarizer, quarter wave plate combination producing circularly polarized light. The circularly polarized light is reflected by a mirror to the cell transverse to the field for optical pumping of the isotopes. Unpolarized light from a readout lamp is directed by lenses to another linear polarizer. The linearly polarized light is reflected by another mirror to the cell transverse to the field and orthogonal to the pump lamp light. The linear light after transversing the cell strikes an analyzer where it is converted to an intensity-modulated light. The modulated light is detected by a photodiode processed and utilized as feedback to control the field and pump lamp excitation and readout of angular displacement.

  11. Partially orthogonal resonators for magnetic resonance imaging

    PubMed Central

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

    2017-01-01

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density. PMID:28186135

  12. Partially orthogonal resonators for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

    2017-02-01

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density.

  13. Magnetic resonance imaging of diabetic foot complications

    PubMed Central

    Low, Keynes TA; Peh, Wilfred CG

    2015-01-01

    This pictorial review aims to illustrate the various manifestations of the diabetic foot on magnetic resonance (MR) imaging. The utility of MR imaging and its imaging features in the diagnosis of pedal osteomyelitis are illustrated. There is often difficulty encountered in distinguishing osteomyelitis from neuroarthropathy, both clinically and on imaging. By providing an accurate diagnosis based on imaging, the radiologist plays a significant role in the management of patients with complications of diabetic foot. PMID:25640096

  14. Magnetic resonance imaging diagnosis of intervertebral disc disease and myelomalacia in an American black bear (Ursus americanus).

    PubMed

    Knafo, S Emmanuelle; Divers, Stephen J; Rech, Raquel; Platt, Simon R

    2012-06-01

    A 23-yr-old black bear (Ursus americanus) was examined because of paralysis of unknown duration. The precise onset of clinical signs was unknown as a result of seasonal torpor. The bear was immobilized and transported to a university veterinary teaching hospital for further evaluation and treatment. Radiography revealed increased mineral opacity and ventral bridging across vertebral segments T8-11. Magnetic resonance imaging demonstrated dorsal and ventral compression of the spinal cord at T8-9. Given the bear's advanced age, the unknown duration of spinal cord compression, unknown presence of deep pain perception, and thus an unknown prognosis for surgical success, euthanasia was elected. Postmortem examination revealed severe spondylosis deformans from T7 to L3 and dorsal extradural extruded disc material in the area of T8-9. Histopathology demonstrated the dorsal horns of the spinal cord at T9 were replaced by foamy macrophages extending into the dorsal and lateral funiculi of the white matter compatible with focal, severe, chronic myelomalacia. This is the first report of intervertebral disc disease and myelomalacia diagnosed using MRI in a large carnivore.

  15. [Contribution of magnetic resonance to the differential diagnosis of a collapsed vertebra in a patient with multiple myeloma].

    PubMed

    Sanz, L; Bladé, J; Olondo, M; Rozman, M; Mercader, J M; Rozman, C; Montserrat, E

    1998-02-01

    The only safe method to determine whether or not patients diagnosed of smoldering myeloma will progress to symptomatic multiple myeloma (MM) is periodic follow-up. In the last years, several studies have emphasized the efficacy of magnetic resonance imaging (MRI) to detect bone marrow involvement in these patients. However, the detection of a focal spinal lesion in elderly patients raises a diagnostic problem, sometimes difficult to solve, between a benign or malignant origin. We present the case of an elderly women with marked osteoporosis and smoldering myeloma who suddenly complained of pain in dorsal spine. MRI showed focal lesions in two dorsal vertebra consistent with myeloma involvement. However, there were no other signs of progression, the lesions were considered secondary to osteoporosis and calcitonin was administered. This resulted in the disappearance of the pain and the MRI abnormalities, which confirmed its benign etiology. The role and limitations of MRI to detect bone marrow involvement by MM in the evaluation of these patients is reviewed.

  16. Usefulness of Magnetic Resonance Neurography for Diagnosis of Piriformis Muscle Syndrome and Verification of the Effect After Botulinum Toxin Type A Injection

    PubMed Central

    Yang, Hea Eun; Park, Jung Hyun; Kim, Sungjun

    2015-01-01

    Abstract Piriformis muscle syndrome (PMS) is a controversial neuromuscular disorder that is presumed to involve compression neuropathy of the sciatic nerve at the level of the piriformis muscle. Botulinum toxin A (BTX-A) injection into the piriformis muscle is widely used as a treatment aimed at relieving sciatic nerve compression. In 2 patients with PMS, magnetic resonance neurography (MRN) was taken before and after BTX-A injection. The first MRN was performed as a diagnostic tool, and the second to identify the effect of the treatment. Signal change of the sciatic nerve under the hypertrophied piriformis muscle was confirmed by MRN. In follow-up MRN performed after BTX-A injection into the piriformis muscle, changes of the sciatic nerve and piriformis muscle were noticed as well as improvement of clinical symptoms. MRN is a useful tool to add certainty of diagnosis and verify the effect of treatment in PMS. PMID:26402805

  17. Usefulness of Magnetic Resonance Neurography for Diagnosis of Piriformis Muscle Syndrome and Verification of the Effect After Botulinum Toxin Type A Injection: Two Cases.

    PubMed

    Yang, Hea Eun; Park, Jung Hyun; Kim, Sungjun

    2015-09-01

    Piriformis muscle syndrome (PMS) is a controversial neuromuscular disorder that is presumed to involve compression neuropathy of the sciatic nerve at the level of the piriformis muscle. Botulinum toxin A (BTX-A) injection into the piriformis muscle is widely used as a treatment aimed at relieving sciatic nerve compression. In 2 patients with PMS, magnetic resonance neurography (MRN) was taken before and after BTX-A injection. The first MRN was performed as a diagnostic tool, and the second to identify the effect of the treatment. Signal change of the sciatic nerve under the hypertrophied piriformis muscle was confirmed by MRN. In follow-up MRN performed after BTX-A injection into the piriformis muscle, changes of the sciatic nerve and piriformis muscle were noticed as well as improvement of clinical symptoms. MRN is a useful tool to add certainty of diagnosis and verify the effect of treatment in PMS.

  18. In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

    PubMed

    Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

    2015-01-01

    Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

  19. Diagnostic accuracy of fat-saturated T2-weighted magnetic resonance imaging in the diagnosis of perforation of the articular disc of the temporomandibular joint.

    PubMed

    Yura, Shinya; Nobata, Koji; Shima, Tsuyoshi

    2012-06-01

    The accuracy of diagnosing a perforation of the articular disc of the temporomandibular joint (TMJ) is poor with conventional magnetic resonance imaging (MRI). We recently reported that a high signal-intensity area is usually found on fat-saturated T2-weighted MRI in the joint space between the articular disc and cartilage surface in joints in which the disc is displaced. A discrete image with an area of high signal-intensity in the middle of the articular disc may indicate perforation or rupture. The purpose of this study was to compare the accuracy of diagnosis of a perforated articular disc by fat-saturated T2-weighted MRI with that of arthroscopy. We studied 50 joints in 50 patients with closed lock of the TMJ who were examined with MRI and then by arthroscopy using an ultra-thin arthroscope. The agreement between the two methods of diagnosis was assessed using the κ coefficient. Evidence of perforation of the disc on MRI and arthroscopically was found in the same 7 joints; there was complete concordance (κ=1.00, p<0.001). The accuracy of diagnosis of perforation of a disc by fat-saturated MRI was therefore the same as that by arthroscopy using an ultra-thin arthroscope.

  20. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Mirijanian, James; Pavell, James

    2015-05-01

    The Nuclear Magnetic Resonance Gyroscope (NMRG) is being developed by the Northrop Grumman Corporation (NGC). Cold and hot atom interferometer based gyroscopes have suffered from Size, Weight, and Power (SWaP) challenges and limits in bandwidth, scale factor stability, dead time, high rotation rate, vibration, and acceleration. NMRG utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as a reference for determining rotation, providing continuous measurement, high bandwidth, stable scale factor, high rotation rate measurement, and low sensitivity to vibration and acceleration in a low SWaP package. The sensitivity to vibration has been partially tested and demonstrates no measured sensitivity within error bars. Real time closed loop implementation of the sensor significantly decreases environmental and systematic sensitivities and supports a compact and low power digital signal processing and control system. Therefore, the NMRG technology holds great promise for navigation grade performance in a low cost SWaP package. The poster will describe the history, operation, and design of the NMRG. General performance results will also be presented along with recent vibration test results.

  1. Role of Perfusion at Rest in the Diagnosis of Myocardial Infarction Using Vasodilator Stress Cardiovascular Magnetic Resonance.

    PubMed

    Patel, Mita B; Mor-Avi, Victor; Kawaji, Keigo; Nathan, Sandeep; Kramer, Christopher M; Lang, Roberto M; Patel, Amit R

    2016-04-01

    In clinical practice, perfusion at rest in vasodilator stress single-photon emission computed tomography is commonly used to confirm myocardial infarction (MI) and ischemia and to rule out artifacts. It is unclear whether perfusion at rest carries similar information in cardiovascular magnetic resonance (CMR). We sought to determine whether chronic MI is associated with abnormal perfusion at rest on CMR. We compared areas of infarct and remote myocardium in 31 patients who underwent vasodilator stress CMR (1.5 T), had MI confirmed by late gadolinium enhancement (LGE scar), and coronary angiography within 6 months. Stress perfusion imaging during gadolinium first pass was followed by reversal with aminophylline (75 to 125 mg), rest perfusion, and LGE imaging. Resting and peak-stress time-intensity curves were used to obtain maximal upslopes (normalized by blood pool upslopes), which were compared between infarcted and remote myocardial regions of interest. At rest, there was no significant difference between the slopes in the regions of interest supplied by arteries with and without stenosis >70% (0.31 ± 0.16 vs 0.26 ± 0.15 1/s), irrespective of LGE scar. However, at peak stress, we found significant differences (0.20 ± 0.11 vs 0.30 ± 0.22 1/s; p <0.05), reflecting the expected stress-induced ischemia. Similarly, at rest, there was no difference between infarcted and remote myocardium (0.27 ± 0.14 vs 0.30 ± 0.17 1/s), irrespective of stenosis, but significant differences were seen during stress (0.21 ± 0.16 vs 0.28 ± 0.18 1/s; p <0.001), reflecting inducible ischemia. In conclusion, abnormalities in myocardial perfusion at rest associated with chronic MI are not reliably detectable on CMR images. Accordingly, unlike single-photon emission computed tomography, normal CMR perfusion at rest should not be used to rule out chronic MI.

  2. [Possibilities of using magnetic resonance imaging-transrectal ultrasound fusion in the diagnosis of recurrent prostate cancer].

    PubMed

    Kapustin, V V

    2011-01-01

    This paper considers whether magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) can be fused, by applying an external bobbin with transrectal ultrasound imaging. The author has studied whether imaging fusion can be used to select a targeted needle biopsy (NB) portion if the development of recurrent prostate cancer (PC) is suspected after radical prostatectomy (RP). MRI-TRUS fusion was performed in 11 patients in different periods after RP. All the patients underwent dynamic contrast-enhanced MRI and then MRI-TRUS fusion during TRUS studies (TRUSS). MRI-TRUS fusion-guided NBs of suspected portions in the vesicourethral anastomotic area were carried out in 7 patients. A control group comprised 18 patients, of whom 12 patients underwent isolated TRUS-guided NB. The use of the fusion technology was shown to make a simultaneous assessment of the MRI and TRUS images of a vesicourethral anastomotic area in post-RP patients. At the same time, the high accuracy of comparison of MRI and TRUS images ensures the steady position of portions with early intensive accumulation of a MRI contrast agent during real-time TRUSS. Thus, morphologically relevant materials could be obtained in 6 of the 7 patients in the MRI-TRUS-guided NB group and only in 3 of the 12 control patients. Therefore, the use of MRI-TRUS fusion enhances the efficiency of NB in post-RP patients suspected of having recurrent PC. The criterion for selecting a target portion is the abnormal accumulation of a MRI contrast agent.

  3. Low field magnetic resonance imaging

    SciTech Connect

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  4. Introduction to nuclear magnetic resonance.

    PubMed

    Mlynárik, Vladimír

    2016-05-19

    Nuclear magnetic resonance spectroscopy is a useful tool for studying normal and pathological biochemical processes in tissues. In this review, the principles of nuclear magnetic resonance and methods of obtaining nuclear magnetic resonance spectra are briefly outlined. The origin of the most important spectroscopic parameters-chemical shifts, coupling constants, longitudinal and transverse relaxation times, and spectroscopic line intensities-is explained, and the role of these parameters in interpretation of spectra is addressed. Basic methodological concepts of localized spectroscopy and spectroscopic imaging for the study of tissue metabolism in vivo are also described.

  5. Functional magnetic resonance imaging.

    PubMed

    Buchbinder, Bradley R

    2016-01-01

    Functional magnetic resonance imaging (fMRI) maps the spatiotemporal distribution of neural activity in the brain under varying cognitive conditions. Since its inception in 1991, blood oxygen level-dependent (BOLD) fMRI has rapidly become a vital methodology in basic and applied neuroscience research. In the clinical realm, it has become an established tool for presurgical functional brain mapping. This chapter has three principal aims. First, we review key physiologic, biophysical, and methodologic principles that underlie BOLD fMRI, regardless of its particular area of application. These principles inform a nuanced interpretation of the BOLD fMRI signal, along with its neurophysiologic significance and pitfalls. Second, we illustrate the clinical application of task-based fMRI to presurgical motor, language, and memory mapping in patients with lesions near eloquent brain areas. Integration of BOLD fMRI and diffusion tensor white-matter tractography provides a road map for presurgical planning and intraoperative navigation that helps to maximize the extent of lesion resection while minimizing the risk of postoperative neurologic deficits. Finally, we highlight several basic principles of resting-state fMRI and its emerging translational clinical applications. Resting-state fMRI represents an important paradigm shift, focusing attention on functional connectivity within intrinsic cognitive networks.

  6. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

    ERIC Educational Resources Information Center

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-01-01

    Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

  7. Pituitary magnetic resonance imaging in Cushing's disease.

    PubMed

    Vitale, Giovanni; Tortora, Fabio; Baldelli, Roberto; Cocchiara, Francesco; Paragliola, Rosa Maria; Sbardella, Emilia; Simeoli, Chiara; Caranci, Ferdinando; Pivonello, Rosario; Colao, Annamaria

    2017-03-01

    Adrenocorticotropin-secreting pituitary tumor represents about 10 % of pituitary adenomas and at the time of diagnosis most of them are microadenomas. Transsphenoidal surgery is the first-line treatment of Cushing's disease and accurate localization of the tumor within the gland is essential for selectively removing the lesion and preserving normal pituitary function. Magnetic resonance imaging is the best imaging modality for the detection of pituitary tumors, but adrenocorticotropin-secreting pituitary microadenomas are not correctly identified in 30-50 % of cases, because of their size, location, and enhancing characteristics. Several recent studies were performed with the purpose of better localizing the adrenocorticotropin-secreting microadenomas through the use in magnetic resonance imaging of specific sequences, reduced contrast medium dose and high-field technology. Therefore, an improved imaging technique for pituitary disease is mandatory in the suspect of Cushing's disease. The aims of this paper are to present an overview of pituitary magnetic resonance imaging in the diagnosis of Cushing's disease and to provide a magnetic resonance imaging protocol to be followed in case of suspicion adrenocorticotropin-secreting pituitary adenoma.

  8. Noble gas magnetic resonator

    DOEpatents

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

  9. Magnetic Resonance Force Microscope Development

    SciTech Connect

    Hammel, P.C.; Zhang, Z.; Suh, B.J.; Roukes, M.L.; Midzor, M.; Wigen, P.E.; Childress, J.R.

    1999-06-03

    Our objectives were to develop the Magnetic Resonance Force Microscope (MRFM) into an instrument capable of scientific studies of buried structures in technologically and scientifically important electronic materials such as magnetic multilayer materials. This work resulted in the successful demonstration of MRFM-detected ferromagnetic resonance (FMR) as a microscopic characterization tool for thin magnetic films. Strong FMR spectra obtained from microscopic Co thin films (500 and 1000 angstroms thick and 40 x 200 microns in lateral extent) allowed us to observe variations in sample inhomogeneity and magnetic anisotropy field. We demonstrated lateral imaging in microscopic FMR for the first time using a novel approach employing a spatially selective local field generated by a small magnetically polarized spherical crystallite of yttrium iron garnet. These successful applications of the MRFM in materials studies provided the basis for our successful proposal to DOE/BES to employ the MRF M in studies of buried interfaces in magnetic materials.

  10. Early History of Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Ramsey, N. F.

    1999-06-01

    The early history of magnetic resonance to around 1950 is discussed from the point of view of a participant in it. I. I. Rabi's theory of space quantization in a gyrating magnetic field and his molecular beam experiments in the 1930s laid the foundation of the magnetic resonance method, which he and his associates subsequently pursued and developed further at Columbia University, leading eventually to the development of NMR after World War II and the invention of the separated oscillatory fields method in 1950.

  11. Optically detected magnetic resonance imaging

    SciTech Connect

    Blank, Aharon; Shapiro, Guy; Fischer, Ran; London, Paz; Gershoni, David

    2015-01-19

    Optically detected magnetic resonance provides ultrasensitive means to detect and image a small number of electron and nuclear spins, down to the single spin level with nanoscale resolution. Despite the significant recent progress in this field, it has never been combined with the power of pulsed magnetic resonance imaging techniques. Here, we demonstrate how these two methodologies can be integrated using short pulsed magnetic field gradients to spatially encode the sample. This result in what we denote as an 'optically detected magnetic resonance imaging' technique. It offers the advantage that the image is acquired in parallel from all parts of the sample, with well-defined three-dimensional point-spread function, and without any loss of spectroscopic information. In addition, this approach may be used in the future for parallel but yet spatially selective efficient addressing and manipulation of the spins in the sample. Such capabilities are of fundamental importance in the field of quantum spin-based devices and sensors.

  12. Role of magnetic resonance imaging and scintigraphy in the diagnosis and follow-up of osteomyelitis in cat-scratch disease.

    PubMed

    Rozmanic, Vojko; Banac, Srdjan; Miletic, Damir; Manestar, Koraljka; Kamber, Silvija; Paparic, Sime

    2007-01-01

    Cat-scratch disease (CSD) is a self-limiting infectious disease characterised with lymphadenopathy in a patient with a history of cat contact. Cases of bone involvement in patients with CSD are rare. We reported a case of 11-year-old boy with prolonged intermittent fever, inguinal lymphadenopathy and osteomyelitis. He had a history of exposure to kittens. The physical examination revealed a febrile boy without an apparent site of infection except an enlarged inguinal lymph node. Its histopathology demonstrated granulomatous lesion with no presence of acid-fast bacilli. Serum titers for Bartonella henselae were positive. Multiple bone lesions were detected by skeletal scintigraphy. Magnetic resonance imaging (MRI) confirmed and characterised osteolytic masses. The oral combination of azithromycin and rifampicin were given for 6 weeks with a good clinical response. At follow-up, the boy was without symptoms or signs of the disease. Successive MRI controls showed gradual regression of the bone lesions together with significant decrease of acute-phase reactants. In conclusion, CSD should be considered in the differential diagnosis of osteomyelitis. MRI is more reliable for the characterisation, evaluation of soft-tissue extension and follow-up of the bone lesions than scintigraphy. However, the later method permits an overview of the multiple osseous lesions. Therefore, standard MRI equipment may not exclude bone scintigraphy. Both methods are required until whole-body MRI units become routine.

  13. Severe Left Ventricular Hypertrophy, Small Pericardial Effusion, and Diffuse Late Gadolinium Enhancement by Cardiac Magnetic Resonance Suspecting Cardiac Amyloidosis: Endomyocardial Biopsy Reveals an Unexpected Diagnosis

    PubMed Central

    Hofmann, Nina P.; Giusca, Sorin; Klingel, Karin; Nunninger, Peter; Korosoglou, Grigorios

    2016-01-01

    Left ventricular (LV) hypertrophy can be related to a multitude of cardiac disorders, such as hypertrophic cardiomyopathy (HCM), cardiac amyloidosis, and hypertensive heart disease. Although the presence of LV hypertrophy is generally associated with poorer cardiac outcomes, the early differentiation between these pathologies is crucial due to the presence of specific treatment options. The diagnostic process with LV hypertrophy requires the integration of clinical evaluation, electrocardiography (ECG), echocardiography, biochemical markers, and if required CMR and endomyocardial biopsy in order to reach the correct diagnosis. Here, we present a case of a patient with severe LV hypertrophy (septal wall thickness of 23 mm, LV mass of 264 g, and LV mass index of 147 g/m2), severely impaired longitudinal function, and preserved radial contractility (ejection fraction = 55%), accompanied by small pericardial effusion and diffuse late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR). Due to the imaging findings, an infiltrative cardiomyopathy, such as cardiac amyloidosis, was suspected. However, amyloid accumulation was excluded by endomyocardial biopsy, which revealed the presence of diffuse myocardial fibrosis in an advanced hypertensive heart disease. PMID:27247807

  14. Magnetic resonance imaging in inflammatory rheumatoid diseases.

    PubMed

    Sudoł-Szopińska, Iwona; Mróz, Joanna; Ostrowska, Monika; Kwiatkowska, Brygida

    2016-01-01

    Magnetic resonance (MR) is used more and more frequently to diagnose changes in the musculoskeletal system in the course of rheumatic diseases, at their initial assessment, for treatment monitoring and for identification of complications. The article presents the history of magnetic resonance imaging, the basic principles underlying its operation as well as types of magnets, coils and MRI protocols used in the diagnostic process of rheumatic diseases. It enumerates advantages and disadvantages of individual MRI scanners. The principles of MRI coil operation are explained, and the sequences used for MR image analysis are described, particularly in terms of their application in rheumatology, including T1-, T2-, PD-weighted, STIR/TIRM and contrast-enhanced T1-weighted images. Furthermore, views on the need to use contrast agents to optimise diagnosis, particularly in synovitis-like changes, are presented. Finally, methods for the assessment of MR images are listed, including the semi-quantitative method by RAMRIS and quantitative dynamic examination.

  15. GHz nuclear magnetic resonance

    SciTech Connect

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  16. The relative contribution of magnetic resonance imaging to the assessment and differential diagnosis of cerebellopontine angle mass lesions.

    PubMed

    Worthington, B S; Mawhinney, R R; Holland, I M; Lowe, J; Punt, J; Bydder, G; Young, I R

    1986-01-01

    Forty-nine patients with a space occupying lesion in the cerebellopontine angle cistern were examined by computed tomography (CT), magnetic imaging (MRI) and, where appropriate, conventional neuroradiologic techniques. The presence of an intracanalicular extension and a high signal on T2 weighted sequences were typical of acoustic neuroma and allowed separation from meningioma. Contrast enhancement with gadolinium DTPA was particularly valuable in recurrent acoustic neuroma. Typically epidermoids had long T1 and T2 values. Sequences which highlight flow allow vascular lesions to be identified without the use of contrast media. In separating the several pathologies MRI was superior to CT and also gave information on tissue composition in acoustic neuroma.

  17. Gadolinium-Enhanced Magnetic Resonance Angiography for Pulmonary Embolism

    PubMed Central

    Stein, Paul D.; Chenevert, Thomas L.; Fowler, Sarah E.; Goodman, Lawrence R.; Gottschalk, Alexander; Hales, Charles A.; Hull, Russell D.; Jablonski, Kathleen A.; Leeper, Kenneth V.; Naidich, David P.; Sak, Daniel J.; Sostman, H. Dirk; Tapson, Victor F.; Weg, John G.; Woodard, Pamela K.

    2011-01-01

    Background The accuracy of gadolinium-enhanced magnetic resonance pulmonary angiography and magnetic resonance venography for diagnosing pulmonary embolism has not been determined conclusively. Objective To investigate performance characteristics of magnetic resonance angiography, with or without magnetic resonance venography, for diagnosing pulmonary embolism. Design Prospective, multicenter study from 10 April 2006 to 30 September 2008. (ClinicalTrials.gov registration number: NCT00241826) Setting 7 hospitals and their emergency services. Patients 371 adults with diagnosed or excluded pulmonary embolism. Measurements Sensitivity, specificity, and likelihood ratios were measured by comparing independently read magnetic resonance imaging with the reference standard for diagnosing pulmonary embolism. Reference standard diagnosis or exclusion was made by using various tests, including computed tomographic angiography and venography, ventilation–perfusion lung scan, venous ultra-sonography, D-dimer assay, and clinical assessment. Results Magnetic resonance angiography, averaged across centers, was technically inadequate in 25% of patients (92 of 371). The proportion of technically inadequate images ranged from 11% to 52% at various centers. Including patients with technically inadequate images, magnetic resonance angiography identified 57% (59 of 104) with pulmonary embolism. Technically adequate magnetic resonance angiography had a sensitivity of 78% and a specificity of 99%. Technically adequate magnetic resonance angiography and venography had a sensitivity of 92% and a specificity of 96%, but 52% of patients (194 of 370) had technically inadequate results. Limitation A high proportion of patients with suspected embolism was not eligible or declined to participate. Conclusion Magnetic resonance pulmonary angiography should be considered only at centers that routinely perform it well and only for patients for whom standard tests are contraindicated. Magnetic

  18. Inhalant-Abuse Myocarditis Diagnosed by Cardiac Magnetic Resonance

    PubMed Central

    Rao, Krishnasree; Matulevicius, Susan

    2016-01-01

    Multiple reports of toxic myocarditis from inhalant abuse have been reported. We now report the case of a 23-year-old man found to have toxic myocarditis from inhalation of a hydrocarbon. The diagnosis was made by means of cardiac magnetic resonance imaging with delayed enhancement. The use of cardiac magnetic resonance to diagnose myocarditis has become increasingly common in clinical medicine, although there is not a universally accepted criterion for diagnosis. We appear to be the first to document a case of toxic myocarditis diagnosed by cardiac magnetic resonance. In patients with a history of drug abuse who present with clinical findings that suggest myocarditis or pericarditis, cardiac magnetic resonance can be considered to support the diagnosis. PMID:27303242

  19. Magnetic Resonance Cholangiopancreatography (MRCP)

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  20. Magnetic Resonance (MR) Defecography

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  1. Magnetic Resonance Cholangiopancreatography (MRCP)

    MedlinePlus

    ... cholangiopancreatography or MRCP uses a powerful magnetic field, radio waves and a computer to evaluate the liver, gallbladder, ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  2. Interventional Cardiovascular Magnetic Resonance Imaging

    PubMed Central

    Saikus, Christina E.; Lederman, Robert J.

    2010-01-01

    Cardiovascular magnetic resonance (CMR) combines excellent soft-tissue contrast, multiplanar views, and dynamic imaging of cardiac function without ionizing radiation exposure. Interventional cardiovascular magnetic resonance (iCMR) leverages these features to enhance conventional interventional procedures or to enable novel ones. Although still awaiting clinical deployment, this young field has tremendous potential. We survey promising clinical applications for iCMR. Next, we discuss the technologies that allow CMR-guided interventions and, finally, what still needs to be done to bring them to the clinic. PMID:19909937

  3. Magnetic resonance apparatus

    DOEpatents

    Jackson, Jasper A.; Cooper, Richard K.

    1982-01-01

    Means for producing a region of homogeneous magnetic field remote from the source of the field, wherein two equal field sources are arranged axially so their fields oppose, producing a region near the plane perpendicular to the axis midway between the sources where the radial component of the field goes through a maximum. Near the maximum, the field is homogeneous over prescribed regions.

  4. Magnetic Resonance Image Wavelet Enhancer

    DTIC Science & Technology

    2007-11-02

    1Departamento de Ingenieria Electrica, UAM Iztapalapa, Mexico−DF, 09340, Mexico email:arog@xanum.uam.mx. Magnetic Resonance Centre, School of Physics...Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Departamento de Ingenieria Electrica, UAM Iztapalapa, Mexico-DF

  5. Magnetic resonance apparatus

    DOEpatents

    Jackson, J.A.; Cooper, R.K.

    1980-10-10

    The patent consists of means for producing a region of homogeneous magnetic field remote from the source of the field, wherein two equal field sources are arranged axially so their fields oppose, producing a region near the plane perpendicular to the axis midway between the sources where the radial correspondent of the field goes through a maximum. Near the maximum, the field is homogeneous over prescribed regions.

  6. The principles of magnetic resonance.

    PubMed

    Longmore, D B

    1989-10-01

    Magnetic Resonance (MR), which has no known biological hazard, is capable of producing high resolution thin tomographic images in any plane and blocks of 3-dimensional information. It can be used to study blood flow and to gain information about the composition of important materials seen and quantified on dimensionally accurate images. The MR image is a thin tomographic slice or a true three dimensional block of data which can be reconstructed in any desired way rather than a shadowgram of all the structures in the beam. It is the only imaging technique which can acquire data in a 3-dimensional format. CT images can be reconstructed to form a pseudo 3-D image or a hologram but the flexibility conferred by acquiring the data as a true 3-D block gives many advantages. The spatial resolution of MR images are theoretically those of low powered microscopy, the practical limits with the present generation of equipment are voxel sizes of one third by one third by two millimetres. The term Magnetic Resonance Imaging (MRI) is used commonly, particularly in the USA, avoiding association with the term, nuclear, and emphasizing the imaging potential of the technique. The terms Nuclear Magnetic Resonance (NMR) or Magnetic Resonance (MR) more correctly describe the most powerful diagnostic instrument yet devised. The simplified description of the phenomena involved in MR which follows is intended to be comprehensive and does not require foreknowledge of classical physics, quantum mechanics, fluency with mathematical formulae or an understanding of image reconstruction. There are many explanations of MR, some omitting the more difficult concepts. An accurate, comprehensive description is found on the textbook on MR by Gadian, Nuclear Magnetic Resonance and its Applications for Living Systems (Oxford University Press, 1982).

  7. Evaluation of the Prostate Imaging Reporting and Data System for Magnetic Resonance Imaging Diagnosis of Prostate Cancer in Patients with Prostate-specific Antigen <20 ng/ml

    PubMed Central

    Wang, Xuan; Wang, Jian-Ye; Li, Chun-Mei; Zhang, Ya-Qun; Wang, Jian-Long; Wan, Ben; Zhang, Wei; Chen, Min; Li, Sa-Ying; Wan, Gang; Liu, Ming

    2016-01-01

    Background: The European Society of Urogenital Radiology has built the Prostate Imaging Reporting and Data System (PI-RADS) for standardizing the diagnosis of prostate cancer (PCa). This study evaluated the PI-RADS diagnosis method in patients with prostate-specific antigen (PSA) <20 ng/ml. Methods: A total of 133 patients with PSA <20 ng/ml were prospectively recruited. T2-weighted (T2WI) and diffusion-weighted (DWI) magnetic resonance images of the prostate were acquired before a 12-core transrectal prostate biopsy. Each patient's peripheral zone was divided into six regions on the images; each region corresponded to two of the 12 biopsy cores. T2WI, DWI, and T2WI + DWI scores were computed according to PI-RADS. The diagnostic accuracy of the PI-RADS score was evaluated using histopathology of prostate biopsies as the reference standard. Results: PCa was histologically diagnosed in 169 (21.2%) regions. Increased PI-RADS score correlated positively with increased cancer detection rate. The cancer detection rate for scores 1 to 5 was 2.8%, 15.0%, 34.6%, 52.6%, and 88.9%, respectively, using T2WI and 12.0%, 20.2%, 48.0%, 85.7%, and 93.3%, respectively, using DWI. For T2WI + DWI, the cancer detection rate was 1.5% (score 2), 13.5% (scores 3–4), 41.3% (scores 5–6), 75.9% (scores 7–8), and 92.3% (scores 9–10). The area under the curve for cancer detection was 0.700 (T2WI), 0.735 (DWI) and 0.749 (T2WI + DWI). The sensitivity and specificity were 53.8% and 89.2%, respectively, when using scores 5–6 as the cutoff value for T2WI + DWI. Conclusions: The PI-RADS score correlates with the PCa detection rate in patients with PSA <20 ng/ml. The summed score of T2WI + DWI has the highest accuracy in detection of PCa. However, the sensitivity should be further improved. PMID:27270538

  8. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    MedlinePlus

    ... to 2-Year-Old Magnetic Resonance Imaging (MRI): Brain KidsHealth > For Parents > Magnetic Resonance Imaging (MRI): Brain ... child may be given headphones to listen to music or earplugs to block the noise, and will ...

  9. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    MedlinePlus

    ... Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. ...

  10. Cardiovascular magnetic resonance assessment of myocardial infarction and post-infarct complications.

    PubMed

    Assomull, Ravi; Cannell, Timothy M; Prasad, Sanjay K

    2005-09-01

    The article discusses the growing role of cardiovascular magnetic resonance in both the diagnosis of myocardial infarction and its subsequent management, including the management of any resulting complications. The current roles of magnetic resonance coronary angiography and magnetic resonance perfusion are also reviewed.

  11. Proton magnetic resonance spectrum of polywater.

    PubMed

    Petsko, G A

    1970-01-09

    With the aid of a time average computer, the proton magnetic resonance spectrum of anomalous water (polywater) is obtained. The spectrum conisists of a single broad resonance shifted approximately 300 hertz downfield from the resonance of ordinary water.

  12. Imaging of myocardial perfusion with magnetic resonance.

    PubMed

    Barkhausen, Jörg; Hunold, Peter; Jochims, Markus; Debatin, Jörg F

    2004-06-01

    Coronary artery disease (CAD) is currently the leading cause of death in developed nations. Reflecting the complexity of cardiac function and morphology, noninvasive diagnosis of CAD represents a major challenge for medical imaging. Although coronary artery stenoses can be depicted with magnetic resonance (MR) and computed tomography (CT) techniques, its functional or hemodynamic impact frequently remains elusive. Therefore, there is growing interest in other, target organ-specific parameters such as myocardial function at stress and first-pass myocardial perfusion imaging to assess myocardial blood flow. This review explores the pathophysiologic background, recent technical developments, and current clinical status of first-pass MR imaging (MRI) of myocardial perfusion.

  13. [Magnetic resonance imaging of the temporomandibular joint].

    PubMed

    Ros Mendoza, L H; Cañete Celestino, E; Velilla Marco, O

    2008-01-01

    The temporomandibular joint (TMJ) is a small joint with complex anatomy and function. Diverse pathologies with very different symptoms can affect the TMJ. While various imaging techniques such as plain-film radiography and computed tomography can be useful, magnetic resonance imaging's superior contrast resolution reveals additional structures like the articular disk, making this technique essential for accurate diagnosis and treatment planning. We analyze the MRI signs of the different pathologies that can affect the TMJ from the structural and functional points of view.

  14. Osteoid osteoma of the scaphoid: magnetic resonance imaging vessel sign.

    PubMed

    Kussman, Steven R; Thompson, Michael; Chang, Eric Y

    2015-01-01

    Osteoid osteomas can be a challenging diagnosis, especially in smaller bones and, particularly, in the carpus. Clinical and imaging diagnosis may both be delayed due to other, more common, post-traumatic or inflammatory pathology in the same area. We present a case of a pathologically proven scaphoid osteoid osteoma with a feeding vessel sign on magnetic resonance imaging, previously described in long bones with computed tomography, as a helpful sign for accurate diagnosis in the scaphoid.

  15. Achilles Impingement Tendinopathy on Magnetic Resonance Imaging.

    PubMed

    Bullock, Mark J; Mourelatos, Jan; Mar, Alice

    2017-02-28

    Haglund's syndrome is impingement of the retrocalcaneal bursa and Achilles tendon caused by a prominence of the posterosuperior calcaneus. Radiographic measurements are not sensitive or specific for diagnosing Haglund's deformity. Localization of a bone deformity and tendinopathy in the same sagittal section of a magnetic resonance imaging scan can assist with the diagnosis in equivocal cases. The aim of the present cross-sectional study was to determine the prevalence of Haglund's syndrome in patients presenting with Achilles tendinopathy and note any associated findings to determine the criteria for a diagnosis of Haglund's syndrome. We reviewed 40 magnetic resonance imaging scans with Achilles tendinopathy and 19 magnetic resonance imaging scans with Achilles high-grade tears and/or ruptures. Achilles tendinopathy was often in close proximity to the superior aspect of the calcaneal tuberosity, consistent with impingement (67.5%). Patients with Achilles impingement tendinopathy were more often female (p < .04) and were significantly heavier than patients presenting with noninsertional Achilles tendinopathy (p = .014) or Achilles tendon rupture (p = .010). Impingement tendinopathy occurred medially (8 of 20) and centrally (10 of 20) more often than laterally (2 of 20) and was associated with a posterior prominence or hyperconvexity with a loss of calcaneal recess more often than a superior projection (22 of 27 versus 8 of 27; p < .001). Haglund's deformity should be reserved for defining a posterior prominence or hyperconvexity with loss of calcaneal recess because this corresponds with impingement. Achilles impingement tendinopathy might be more appropriate terminology for Haglund's syndrome, because the bone deformity is often subtle. Of the 27 images with Achilles impingement tendinopathy, 10 (37.0%) extended to a location prone to Achilles tendon rupture. Given these findings, insertional and noninsertional Achilles tendinopathy are not mutually

  16. Nuclear magnetic resonance imaging of liver hemangiomas

    SciTech Connect

    Sigal, R.; Lanir, A.; Atlan, H.; Naschitz, J.E.; Simon, J.S.; Enat, R.; Front, D.; Israel, O.; Chisin, R.; Krausz, Y.

    1985-10-01

    Nine patients with cavernous hemangioma of the liver were examined by nuclear magnetic resonance imaging (MRI) with a 0.5 T superconductive magnet. Spin-echo technique was used with varying time to echo (TE) and repetition times (TR). Results were compared with /sup 99m/Tc red blood cell (RBC) scintigraphy, computed tomography (CT), echography, and arteriography. Four illustrated cases are reported. It was possible to establish a pattern for MRI characteristics of cavernous hemangiomas; rounded or smooth lobulated shape, marked increase in T1 and T2 values as compared with normal liver values. It is concluded that, although more experience is necessary to compare the specificity with that of ultrasound and CT, MRI proved to be very sensitive for the diagnosis of liver hemangioma, especially in the case of small ones which may be missed by /sup 99m/Tc-labeled RBC scintigraphy.

  17. Wide-range nuclear magnetic resonance detector

    NASA Technical Reports Server (NTRS)

    Sturman, J. C.; Jirberg, R. J.

    1972-01-01

    Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments.

  18. Nerves on magnetic resonance imaging.

    PubMed Central

    Collins, J. D.; Shaver, M. L.; Batra, P.; Brown, K.

    1989-01-01

    Nerves are often visualized on magnetic resonance imaging (MRI) studies of the soft tissues on the chest and shoulder girdle. To learn the reasons for the contrast between the nerves and adjacent tissues, the authors obtained a fresh specimen containing part of the brachial plexus nerves from the left axilla and compared MRI with x-ray projections and photomicrographs of histologic sections. The results suggest that the high signals from the nerves stand out in contrast to the low signals from their rich vascular supply. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6A Figure 6B Figure 7 PMID:2733051

  19. Magnetic resonance spectroscopy of the human brain

    NASA Astrophysics Data System (ADS)

    Strózik-Kotlorz, D.

    2014-01-01

    I give a brief description of the magnetic resonance spectroscopy (MRS) in the human brain examinations. MRS allows a noninvasive chemical analysis of the brain using a standard high field MR system. Nowadays, the dominant form of MR brain spectroscopy is proton spectroscopy. Two main techniques of MRS, which utilize the chemical shift of metabolites in the external magnetic field, are SVS (single voxel) and CSI (single slice). The major peaks in the spectrum of a normal brain include NAA, Cr, Cho and m-Ins, which are neuronal, energetic, membrane turnover and glial markers, respectively. In disease, two pathological metabolites can be found in the brain spectra: Lac, which is end product of anaerobic glycolysis and Lip, which is a marker of membrane breakdown, occurring in necrosis. The common way to analyze clinical spectra is to determine metabolite ratios, e.g. NAA/Cr, Cho/Cr, Cho/NAA. This analysis permits a safe and noninvasive examination of the brain tissue as each disease state has its own characteristic spectroscopic image. MRS is a valuable diagnostic tool in such clinical applications as detecting brain tumors and differentiating tumors from inflammatory and infectious processes. Proton MRS is also very helpful in diagnostic of ischemic lesions, Alzheimer's disease and hepatic encephalopathy. The MRS brain spectra should always be correlated with the Magnetic Resonance Imaging (MRI) results and alone cannot make neurological diagnosis.

  20. Magnetic resonance imaging in inflammatory rheumatoid diseases

    PubMed Central

    Mróz, Joanna; Ostrowska, Monika; Kwiatkowska, Brygida

    2016-01-01

    Magnetic resonance (MR) is used more and more frequently to diagnose changes in the musculoskeletal system in the course of rheumatic diseases, at their initial assessment, for treatment monitoring and for identification of complications. The article presents the history of magnetic resonance imaging, the basic principles underlying its operation as well as types of magnets, coils and MRI protocols used in the diagnostic process of rheumatic diseases. It enumerates advantages and disadvantages of individual MRI scanners. The principles of MRI coil operation are explained, and the sequences used for MR image analysis are described, particularly in terms of their application in rheumatology, including T1-, T2-, PD-weighted, STIR/TIRM and contrast-enhanced T1-weighted images. Furthermore, views on the need to use contrast agents to optimise diagnosis, particularly in synovitis-like changes, are presented. Finally, methods for the assessment of MR images are listed, including the semi-quantitative method by RAMRIS and quantitative dynamic examination. PMID:27826171

  1. Introduction to Nuclear Magnetic Resonance

    NASA Technical Reports Server (NTRS)

    Manatt, Stanley L.

    1985-01-01

    The purpose of this paper is to try to give a short overview of what the status is on nuclear magnetic resonance (NMR). It's a subject where one really has to spend some time to look at the physics in detail to develop a proper working understanding. I feel it's not appropriate to present to you density matrices, Hamiltonians of all sorts, and differential equations representing the motion of spins. I'm really going to present some history and status, and show a few very simple concepts involved in NMR. It is a form of radio frequency spectroscopy and there are a great number of nuclei that can be studied very usefully with the technique. NMR requires a magnet, a r.f. transmitter/receiver system, and a data acquisition system.

  2. Tunable Magnetic Resonance in Microwave Spintronics Devices

    NASA Technical Reports Server (NTRS)

    Chen, Yunpeng; Fan, Xin; Xie, Yungsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe-based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  3. Tunable Magnetic Resonance in Microwave Spintronics Devices

    NASA Technical Reports Server (NTRS)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  4. Magnetic resonance imaging-targeted, 3D transrectal ultrasound-guided fusion biopsy for prostate cancer: Quantifying the impact of needle delivery error on diagnosis

    SciTech Connect

    Martin, Peter R.; Cool, Derek W.; Romagnoli, Cesare; Fenster, Aaron; Ward, Aaron D.

    2014-07-15

    Purpose: Magnetic resonance imaging (MRI)-targeted, 3D transrectal ultrasound (TRUS)-guided “fusion” prostate biopsy intends to reduce the ∼23% false negative rate of clinical two-dimensional TRUS-guided sextant biopsy. Although it has been reported to double the positive yield, MRI-targeted biopsies continue to yield false negatives. Therefore, the authors propose to investigate how biopsy system needle delivery error affects the probability of sampling each tumor, by accounting for uncertainties due to guidance system error, image registration error, and irregular tumor shapes. Methods: T2-weighted, dynamic contrast-enhanced T1-weighted, and diffusion-weighted prostate MRI and 3D TRUS images were obtained from 49 patients. A radiologist and radiology resident contoured 81 suspicious regions, yielding 3D tumor surfaces that were registered to the 3D TRUS images using an iterative closest point prostate surface-based method to yield 3D binary images of the suspicious regions in the TRUS context. The probabilityP of obtaining a sample of tumor tissue in one biopsy core was calculated by integrating a 3D Gaussian distribution over each suspicious region domain. Next, the authors performed an exhaustive search to determine the maximum root mean squared error (RMSE, in mm) of a biopsy system that gives P ≥ 95% for each tumor sample, and then repeated this procedure for equal-volume spheres corresponding to each tumor sample. Finally, the authors investigated the effect of probe-axis-direction error on measured tumor burden by studying the relationship between the error and estimated percentage of core involvement. Results: Given a 3.5 mm RMSE for contemporary fusion biopsy systems,P ≥ 95% for 21 out of 81 tumors. The authors determined that for a biopsy system with 3.5 mm RMSE, one cannot expect to sample tumors of approximately 1 cm{sup 3} or smaller with 95% probability with only one biopsy core. The predicted maximum RMSE giving P ≥ 95% for each

  5. [The specificity and limitations of sacroiliac joint magnetic resonance imaging in the diagnosis of axial spondyloarthritis in patients with chronic low back pain].

    PubMed

    Wang, Y Y; Zhao, Z; Luo, G; Li, Y; Zhang, J L; Huang, F

    2016-11-01

    Objective: To evaluate the specificity and limitations of sacroiliac joint magnetic resonance imaging (MRI) in the diagnosis of axial spondyloarthritis (SpA)in patients with chronic low back pain. Methods: We retrospectively analyzed clinical data of 390 patients with chronic low back pain in Department of Rheumatology, the PLA General Hospital from January 2013 to December 2015, including clinical manifestations, laboratory examinations and MRI data of sacroiliac joints. Results: There were 238 men and 152 women recruited. A total of 326 cases were diagnosed as axial SpA, including 216 men and 110 women with mean age (27.10±8.64) years and mean duration (7.64±3.50) months. Among these 326 patients, 243 (74.5%) were HLA-B27 positive. The other 64 patients were considered as diagnoses rather than SpA (non-SpA), consisting of 22 men and 42 women with mean age (31.29±7.76) years and mean duration (5.75±2.90)months. Non-SpA group had 10 (15.6%) patients with HLA-B27 positive. There were 68.1% and 65.0% SpA patients showing bone marrow edema and bone erosion of sacroiliac joint in MRI imaging respectively. Although there were 25.0% non-SpA patients with bone marrow edema and 7.8% with bone erosion in MRI of sacroiliac joint, the scores of bone marrow edema 0.00(0.00, 0.75) and bone erosion [0.00(0.00, 0.00)] were significantly lower compared with those in axial SpA group [bone marrow edema scores 2.00(0.00, 4.00), bone erosion scores 1.00(0.00, 3.00); P<0.05]. The scores of fat infiltration [1.00(0.00, 4.25), 1.00(0.00, 4.00)] and bone sclerosis [0.00(0.00, 1.00), 0.00(0.00, 1.75)] were not statistically different between two groups. Diagnostic sensitivity of bone marrow edema and bone erosion for axial SpA were 56.4% and 64.1% respectively, specificity were 93.8% and 92.2% respectively. The positive predictive value of bone marrow edema and bone erosion for axial SpA were 9.09 and 8.21, negative predictive value were 0.46 and 0.38.Diagnositic sensitivity of fatty

  6. MAGNETIC RESONANCE ELASTOGRAPHY: A REVIEW

    PubMed Central

    Mariappan, Yogesh K; Glaser, Kevin J; Ehman, Richard L

    2011-01-01

    Magnetic Resonance Elastography (MRE) is a rapidly developing technology for quantitatively assessing the mechanical properties of tissue. The technology can be considered to be an imaging-based counterpart to palpation, commonly used by physicians to diagnose and characterize diseases. The success of palpation as a diagnostic method is based on the fact that the mechanical properties of tissues are often dramatically affected by the presence of disease processes such as cancer, inflammation, and fibrosis. MRE obtains information about the stiffness of tissue by assessing the propagation of mechanical waves through the tissue with a special magnetic resonance imaging (MRI) technique. The technique essentially involves three steps: generating shear waves in the tissue,acquiring MR images depicting the propagation of the induced shear waves andprocessing the images of the shear waves to generate quantitative maps of tissue stiffness, called elastograms. MRE is already being used clinically for the assessment of patients with chronic liver diseases and is emerging as a safe, reliable and noninvasive alternative to liver biopsy for staging hepatic fibrosis. MRE is also being investigated for application to pathologies of other organs including the brain, breast, blood vessels, heart, kidneys, lungs and skeletal muscle. The purpose of this review article is to introduce this technology to clinical anatomists and to summarize some of the current clinical applications that are being pursued. PMID:20544947

  7. [Diagnostic approach to cardiopathies by means of magnetic resonance imaging].

    PubMed

    Gutiérrez Zamora, Agustín

    2005-01-01

    Cardiomyopathies encompass a broad spectrum of heart pathologies having a basic principle, the intrinsic injury of the myocardial fiber. By definition, cardiomyopathies could be primary (dilated cardiomyopathy), or can be a consequence of another cardiovascular illness (high blood pressure), or of genetic anomalies, such as hypertrophic cardiomyopathy, or due to alterations in myocytes due to fibrolipidic material as occurs in right ventricle arrhythmogenic dysplasia. Currently, magnetic resonance imaging is the best method to approach the diagnosis of these pathologies. Magnetic resonance imaging has allowed us to study histological sections through adequate sequences and using gadolinium as contrast agent. We present herein a simple way to approach the diagnosis of cardiomyopathies by means of magnetic resonance imaging methods.

  8. Advances in mechanical detection of magnetic resonance

    PubMed Central

    Kuehn, Seppe; Hickman, Steven A.; Marohn, John A.

    2008-01-01

    The invention and initial demonstration of magnetic resonance force microscopy (MRFM) in the early 1990s launched a renaissance of mechanical approaches to detecting magnetic resonance. This article reviews progress made in MRFM in the last decade, including the demonstration of scanned probe detection of magnetic resonance (electron spin resonance, ferromagnetic resonance, and nuclear magnetic resonance) and the mechanical detection of electron spin resonance from a single spin. Force and force-gradient approaches to mechanical detection are reviewed and recent related work using attonewton sensitivity cantilevers to probe minute fluctuating electric fields near surfaces is discussed. Given recent progress, pushing MRFM to single proton sensitivity remains an exciting possibility. We will survey some practical and fundamental issues that must be resolved to meet this challenge. PMID:18266413

  9. Torque-mixing magnetic resonance spectroscopy.

    PubMed

    Losby, J E; Fani Sani, F; Grandmont, D T; Diao, Z; Belov, M; Burgess, J A J; Compton, S R; Hiebert, W K; Vick, D; Mohammad, K; Salimi, E; Bridges, G E; Thomson, D J; Freeman, M R

    2015-11-13

    A universal, torque-mixing method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by magnetic induction, the transverse component of a precessing dipole moment can be measured in sensitive broadband spectroscopy, here using a resonant mechanical torque sensor. Unlike induction, the torque amplitude allows equilibrium magnetic properties to be monitored simultaneously with the spin dynamics. Comprehensive electron spin resonance spectra of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature reveal assisted switching between magnetization states and mode-dependent spin resonance interactions with nanoscale surface imperfections. The rich detail allows analysis of even complex three-dimensional spin textures. The flexibility of microelectromechanical and optomechanical devices combined with broad generality and capabilities of torque-mixing magnetic resonance spectroscopy offers great opportunities for development of integrated devices.

  10. Thoracic outlet syndromes and magnetic resonance imaging.

    PubMed

    Panegyres, P K; Moore, N; Gibson, R; Rushworth, G; Donaghy, M

    1993-08-01

    The thoracic outlet syndromes encompass the diverse clinical entities affecting the branchial plexus or subclavian artery including cervical ribs or bands. Thoracic outlet syndrome are often difficult to diagnose on existing clinical and electrophysiological criteria and new diagnostic methods are necessary. This study reports our experience with magnetic resonance imaging (MRI) of the brachial plexus in 20 patients with suspected thoracic outlet syndrome. The distribution of pain and sensory disturbance varied widely, weakness and wasting usually affected C8/T1 innervated muscles, and electrophysiology showed combinations of reduced sensory nerve action potentials from the fourth and fifth digits, and prolonged F-responses or tendon reflex latencies. The MRI study was interpreted blind. Deviation of the brachial plexus was recorded in 19 out of the 24 symptomatic sides (sensitivity 79%). Absence of distortion was correctly identified in 14 out of 16 asymptomatic sides (specificity 87.5%). The false positive rate was 9.5%. Magnetic resonance imaging demonstrated all seven cervical ribs visible on plain cervical spine radiographs. Magnetic resonance imaging also showed a band-like structure extending from the C7 transverse process in 25 out of 33 sides; similar structures were detected in three out of 18 sides in control subjects. These MRI bands often underlay the brachial plexus distortion observed in our patients. We also observed instances of plexus distortion by post-traumatic callus of the first rib, and by a hypertrophied serratus anterior muscle. If they did not demonstrate a cervical rib, plain cervical spine radiographs had no value in predicting brachial plexus distortion. We believe MRI to be of potential value in the diagnosis of thoracic outlet syndrome by: (i) demonstrating deviation or distortion of nerves or blood vessels; (ii) suggesting the presence of radiographically invisible bands; (iii) disclosing other causes of thoracic outlet syndrome

  11. [Surface coils for magnetic-resonance images].

    PubMed

    Rodríguez-González, Alfredo Odón; Amador-Baheza, Ricardo; Rojas-Jasso, Rafael; Barrios-Alvarez, Fernando Alejandro

    2005-01-01

    Since the introduction of magnetic resonance imaging in Mexico, the development of this important medical imaging technology has been almost non-existing in our country. The very first surface coil prototypes for clinical applications in magnetic resonance imaging has been developed at the Center of Research in Medical Imaging and Instrumentation of the Universidad Autónoma Metropolitana Iztapalapa (Metropolitan Autonomous University, Campus Iztapalapa). Two surface coil prototypes were built: a) a circular-shaped coil and b) a square-shaped coil for multiple regions of the body, such as heart, brain, knee, hands, and ankles. These coils were tested on the 1.5T imager of the ABC Hospital-Tacubaya, located in Mexico City. Brain images of healthy volunteers were obtained in different orientations: sagittal, coronal, and axial. Since images showed a good-enough clinical quality for diagnosis, it is fair to say that these coil prototypes can be used in the clinical environment, and with small modifications, they can be made compatible with almost any commercial scanner. This type of development can offer new alternatives for further collaboration between the research centers and the radiology community, in the search of new applications and developments of this imaging technique.

  12. Magnetic resonance elastography hardware design: a survey.

    PubMed

    Tse, Z T H; Janssen, H; Hamed, A; Ristic, M; Young, I; Lamperth, M

    2009-05-01

    Magnetic resonance elastography (MRE) is an emerging technique capable of measuring the shear modulus of tissue. A suspected tumour can be identified by comparing its properties with those of tissues surrounding it; this can be achieved even in deep-lying areas as long as mechanical excitation is possible. This would allow non-invasive methods for cancer-related diagnosis in areas not accessible with conventional palpation. An actuating mechanism is required to generate the necessary tissue displacements directly on the patient in the scanner and three different approaches, in terms of actuator action and position, exist to derive stiffness measurements. However, the magnetic resonance (MR) environment places considerable constraints on the design of such devices, such as the possibility of mutual interference between electrical components, the scanner field, and radio frequency pulses, and the physical space restrictions of the scanner bore. This paper presents a review of the current solutions that have been developed for MRE devices giving particular consideration to the design criteria including the required vibration frequency and amplitude in different applications, the issue of MR compatibility, actuation principles, design complexity, and scanner synchronization issues. The future challenges in this field are also described.

  13. Magnetic resonance imaging of fetal pelvic cysts.

    PubMed

    Archontaki, Styliani; Vial, Yvan; Hanquinet, Sylviane; Meuli, Reto; Alamo, Leonor

    2016-12-01

    The detection of fetal anomalies has improved in the last years as a result of the generalization of ultrasound pregnancy screening exams. The presence of a cystic imaging in the fetal pelvis is a relatively common finding, which can correspond to a real congenital cystic lesion or result from the anomalous liquid accumulation in a whole pelvic organ, mainly the urinary bladder, the uterus, or the vagina. In selected cases with poor prognosis and/or inconclusive echographic findings, magnetic resonance may bring additional information in terms of the characterization, anatomical location, and real extension of the pathology. This pictorial essay describes the normal pelvic fetal anatomy, as well as the most common pelvic cysts. It also describes the causes of an anomalous distension of the whole pelvic organs detected in utero, with emphasis on prenatal magnetic resonance imaging exams. Moreover, it proposes practical teaching points to reduce the differential diagnosis of these lesions based on the sex of the fetus, the division of the pelvis in anatomical spaces, and the imaging findings of the pathology. Finally, it discusses the real utility of complementary MRI.

  14. Antenatal Diagnosis of a Large Immature Abdominal Wall Teratoma by 2D-3D Ultrasound Using HDlive and Magnetic Resonance Imaging.

    PubMed

    Werner, Heron; Mocarzel, Carolina; Sá, Renato Augusto; Tonni, Gabriele; Novoa Y Novoa, Victoria Arruga; Avvad-Portari, Elyzabeth; Bonasoni, Paola; Araujo Júnior, Edward

    2016-01-01

    We describe the first case of prenatally detected teratoma of the fetal abdomen wall using ultrasound and fetal magnetic resonance imaging (MRI). A heterogeneous mass, partly solid and cystic, originating from the anterior abdominal wall of the fetus close to an omphalocele sac was detected by means of 2D/3D ultrasound and MRI. Amniodrainage was performed and due to sign of impending fetal risk, an emergency Cesarean section was performed. A bulky, crumbly and bleeding tumoral mass was confirmed at delivery. Ligation of the supplying artery to the tumor was complicated by uncontrollable hemorrhage and early neonatal death. Pathology identified the tumor as an immature teratoma of the anterior fetal abdominal wall. 2D/3D ultrasound, especially using HDlive application and MRI demonstrated accurate detection and characterization of this congenital tumor.

  15. Magnetic Resonance Imaging of Electrolysis.

    NASA Astrophysics Data System (ADS)

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-02-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research.

  16. Functional Magnetic Resonance Imaging Methods

    PubMed Central

    Chen, Jingyuan E.; Glover, Gary H.

    2015-01-01

    Since its inception in 1992, Functional Magnetic Resonance Imaging (fMRI) has become an indispensible tool for studying cognition in both the healthy and dysfunctional brain. FMRI monitors changes in the oxygenation of brain tissue resulting from altered metabolism consequent to a task-based evoked neural response or from spontaneous fluctuations in neural activity in the absence of conscious mentation (the “resting state”). Task-based studies have revealed neural correlates of a large number of important cognitive processes, while fMRI studies performed in the resting state have demonstrated brain-wide networks that result from brain regions with synchronized, apparently spontaneous activity. In this article, we review the methods used to acquire and analyze fMRI signals. PMID:26248581

  17. Magnetic Resonance Elastography of Abdomen

    PubMed Central

    Venkatesh, Sudhakar K.; Ehman, Richard L.

    2015-01-01

    Many diseases cause substantial changes in the mechanical properties of tissue and this provides motivation for developing methods to non-invasively assess the stiffness of tissue using imaging technology. Magnetic resonance elastography (MRE) has emerged as a versatile MRI-based technique, based on direct visualization of propagating shear waves in the tissues. The most established clinical application of MRE in the abdomen is in chronic liver disease. MRE is currently regarded as the most accurate non-invasive technique for detection and staging of liver fibrosis. Increasing experience and ongoing research is leading to exploration of applications in other abdominal organs. In this review article, the current use of MRE in liver disease and the potential future applications of this technology in other parts of the abdomen are surveyed. PMID:25488346

  18. Microcoil nuclear magnetic resonance spectroscopy.

    PubMed

    Webb, A G

    2005-08-10

    In comparison with most analytical chemistry techniques, nuclear magnetic resonance has an intrinsically low sensitivity, and many potential applications are therefore precluded by the limited available quantity of certain types of sample. In recent years, there has been a trend, both commercial and academic, towards miniaturization of the receiver coil in order to increase the mass sensitivity of NMR measurements. These small coils have also proved very useful in coupling NMR detection with commonly used microseparation techniques. A further development enabled by small detectors is parallel data acquisition from many samples simultaneously, made possible by incorporating multiple receiver coils into a single NMR probehead. This review article summarizes recent developments and applications of "microcoil" NMR spectroscopy.

  19. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

    ERIC Educational Resources Information Center

    McQuarrie, Donald A.

    1988-01-01

    Discusses how to interpret nuclear magnetic resonance (NMR) spectra and how to use them to determine molecular structures. This discussion is limited to spectra that are a result of observation of only the protons in a molecule. This type is called proton magnetic resonance (PMR) spectra. (CW)

  20. Magnetic resonance imaging of radiation optic neuropathy

    SciTech Connect

    Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S. )

    1990-10-15

    Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence.

  1. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    ERIC Educational Resources Information Center

    Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

    2008-01-01

    The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

  2. Prostate magnetic resonance imaging: challenges of implementation.

    PubMed

    Loch, Ronald; Fowler, Kathryn; Schmidt, Ryan; Ippolito, Joseph; Siegel, Cary; Narra, Vamsi

    2015-01-01

    Prostate cancer is among the most common causes of cancer and cancer deaths in men. Screening methods and optimal treatments have become controversial in recent years. Prostate magnetic resonance imaging (MRI) is gaining popularity as a tool to assist diagnosis, risk assessment, and staging. However, implementation into clinical practice can be difficult, with many challenges associated with image acquisition, postprocessing, interpretation, reporting, and radiologic-pathologic correlation. Although state-of-the-art technology is available at select sites for targeting tissue biopsy and interpreting multiparametric prostate MRI, many institutions struggle with adapting this new technology into an efficient multidisciplinary model of patient care. This article reviews several of the challenges that radiologists should be aware of when integrating prostate MRI into their clinical practice.

  3. Magnetic resonance imaging of pancreatitis: An update

    PubMed Central

    Manikkavasakar, Sriluxayini; AlObaidy, Mamdoh; Busireddy, Kiran K; Ramalho, Miguel; Nilmini, Viragi; Alagiyawanna, Madhavi; Semelka, Richard C

    2014-01-01

    Magnetic resonance (MR) imaging plays an important role in the diagnosis and staging of acute and chronic pancreatitis and may represent the best imaging technique in the setting of pancreatitis due to its unmatched soft tissue contrast resolution as well as non-ionizing nature and higher safety profile of intravascular contrast media, making it particularly valuable in radiosensitive populations such as pregnant patients, and patients with recurrent pancreatitis requiring multiple follow-up examinations. Additional advantages include the ability to detect early forms of chronic pancreatitis and to better differentiate adenocarcinoma from focal chronic pancreatitis. This review addresses new trends in clinical pancreatic MR imaging emphasizing its role in imaging all types of acute and chronic pancreatitis, pancreatitis complications and other important differential diagnoses that mimic pancreatitis. PMID:25356038

  4. Multidimensionally encoded magnetic resonance imaging.

    PubMed

    Lin, Fa-Hsuan

    2013-07-01

    Magnetic resonance imaging (MRI) typically achieves spatial encoding by measuring the projection of a q-dimensional object over q-dimensional spatial bases created by linear spatial encoding magnetic fields (SEMs). Recently, imaging strategies using nonlinear SEMs have demonstrated potential advantages for reconstructing images with higher spatiotemporal resolution and reducing peripheral nerve stimulation. In practice, nonlinear SEMs and linear SEMs can be used jointly to further improve the image reconstruction performance. Here, we propose the multidimensionally encoded (MDE) MRI to map a q-dimensional object onto a p-dimensional encoding space where p > q. MDE MRI is a theoretical framework linking imaging strategies using linear and nonlinear SEMs. Using a system of eight surface SEM coils with an eight-channel radiofrequency coil array, we demonstrate the five-dimensional MDE MRI for a two-dimensional object as a further generalization of PatLoc imaging and O-space imaging. We also present a method of optimizing spatial bases in MDE MRI. Results show that MDE MRI with a higher dimensional encoding space can reconstruct images more efficiently and with a smaller reconstruction error when the k-space sampling distribution and the number of samples are controlled.

  5. Novel detection schemes of nuclear magnetic resonance and magnetic resonance imaging: applications from analytical chemistry to molecular sensors.

    PubMed

    Harel, Elad; Schröder, Leif; Xu, Shoujun

    2008-01-01

    Nuclear magnetic resonance (NMR) is a well-established analytical technique in chemistry. The ability to precisely control the nuclear spin interactions that give rise to the NMR phenomenon has led to revolutionary advances in fields as diverse as protein structure determination and medical diagnosis. Here, we discuss methods for increasing the sensitivity of magnetic resonance experiments, moving away from the paradigm of traditional NMR by separating the encoding and detection steps of the experiment. This added flexibility allows for diverse applications ranging from lab-on-a-chip flow imaging and biological sensors to optical detection of magnetic resonance imaging at low magnetic fields. We aim to compare and discuss various approaches for a host of problems in material science, biology, and physics that differ from the high-field methods routinely used in analytical chemistry and medical imaging.

  6. Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

    MedlinePlus

    ... If You Have Questions en español Resonancia magnética: columna lumbar What It Is Magnetic resonance imaging (MRI) ... MORE ON THIS TOPIC Magnetic Resonance Imaging (MRI): Cervical Spine Lumbar Puncture (Spinal Tap) Magnetic Resonance Imaging ( ...

  7. Magnetic resonance imaging of the central nervous system

    SciTech Connect

    Brant-Zawadzki, M.; Norman, D.

    1987-01-01

    This text provides an introduction to magnetic resonance imaging (MRI) of disorders of the central nervous system, spine, neck, and nasopharynx. The book offers guidance in performing and interpreting MRI studies for specific clinical problems. Included are more than 800 images showing pathologic findings for various disorders and demonstrating how abnormalities detected in MRI scans can aid both in differential diagnosis and in clinical staging. The book summarizes the basic principles of MRI and describes the major equipment components and contrast agents. A review of the principles and potential applications of magnetic resonance spectroscopy is also included.

  8. Unusual Presentation of Popliteal Cyst on Magnetic Resonance Imaging

    PubMed Central

    Takahashi, Masaaki; Suzuki, Daisuke; Matsuyama, Yukihiro

    2016-01-01

    Popliteal cyst commonly presents as an ellipsoid mass with uniform low signal intensity on T1-weighted magnetic resonance images and high signal intensity on T2-weighted images. Here, we describe a popliteal cyst with unusual appearance on magnetic resonance imaging, including heterogeneous intermediate signal intensity on T2-weighted images. Arthroscopic cyst decompression revealed that the cyst was filled with necrotic synovial villi, indicative of rheumatoid arthritis. Arthroscopic enlargement of unidirectional valvular slits with synovectomy was useful for the final diagnosis and treatment. PMID:27999700

  9. Stepped impedance resonators for high-field magnetic resonance imaging.

    PubMed

    Akgun, Can E; DelaBarre, Lance; Yoo, Hyoungsuk; Sohn, Sung-Min; Snyder, Carl J; Adriany, Gregor; Ugurbil, Kamil; Gopinath, Anand; Vaughan, J Thomas

    2014-02-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high-field magnetic resonance imaging. In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections, referred to as stepped impedance resonators (SIRs), is investigated. Single-element simulation results in free space and in a phantom at 7 T (298 MHz) demonstrate the rationale and feasibility of the SIR design strategy. Simulation and image results at 7 T in a phantom and human head illustrate the improvements in a transmit magnetic field, as well as RF efficiency (transmit magnetic field versus specific absorption rate) when two different SIR designs are incorporated in 8-element volume coil configurations and compared to a volume coil consisting of microstrip elements.

  10. Stepped Impedance Resonators for High Field Magnetic Resonance Imaging

    PubMed Central

    Akgun, Can E.; DelaBarre, Lance; Yoo, Hyoungsuk; Sohn, Sung-Min; Snyder, Carl J.; Adriany, Gregor; Ugurbil, Kamil; Gopinath, Anand; Vaughan, J. Thomas

    2014-01-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high field magnetic resonance imaging (MRI). In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) multi-element transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections referred to as stepped impedance resonators (SIRs) is investigated. Single element simulation results in free space and in a phantom at 7 tesla (298 MHz) demonstrate the rationale and feasibility of the SIR design strategy. Simulation and image results at 7 tesla in a phantom and human head illustrate the improvements in transmit magnetic field, as well as, RF efficiency (transmit magnetic field versus SAR) when two different SIR designs are incorporated in 8-element volume coil configurations and compared to a volume coil consisting of microstrip elements. PMID:23508243

  11. Development of poly(vinyl acetate-methylacrylic acid)/chitosan/Fe3O4 nanoparticles for the diagnosis of non-alcoholic steatohepatitis with magnetic resonance imaging.

    PubMed

    Luo, Xiadan; Song, Xiaoli; Zhu, Aiping; Si, Yunfeng; Ji, Lijun; Ma, Zhanrong; Jiao, Zhiyun; Wu, Jingtao

    2012-12-01

    Non-alcoholic steatohepatitis is a burgeoning health problem. To diagnose NASH with magnetic resonance imaging (MRI), an effective contrast agent, a stable suspension of superparamagnetic Fe(3)O(4) nanoparticles, were newly developed. The negatively charged Fe(3)O(4) nanoparticles were coated with positive chitosan (CS) firstly, and then assembled with poly(vinyl acetate-methylacrylic acid) (P(VAc-MAA)). Transmission electron microscope and dynamic light scattering confirmed that the obtained P(VAc-MAA)/CS/Fe(3)O(4) nanoparticles had a spherical or ellipsoidal morphology with an average diameter in the range of 14-20 nm. The superparamagnetic property and spinel structure of the Fe(3)O(4) nanoparticles were well preserved due to the protection of the P(VAc-MAA)/CS layers on the surface of the Fe(3)O(4) nanoparticles. The in vivo rat experiments confirmed that the P(VAc-MAA)/CS/Fe(3)O(4) nanoparticles were an effective contrast agent for MRI to diagnose NASH.

  12. Efficacy of magnetic resonance imaging in the diagnosis of perianal hidradenitis suppurativa, complicated by anal fistulae: A report of two cases and review of the literature

    PubMed Central

    Takiyama, Hirotoshi; Kazama, Shinsuke; Tanoue, Yusuke; Yasuda, Koji; Otani, Kensuke; Nishikawa, Takeshi; Tanaka, Toshiaki; Tanaka, Junichiro; Kiyomatsu, Tomomichi; Hata, Keisuke; Kawai, Kazushige; Nozawa, Hiroaki; Miyagawa, Takuya; Yamada, Daisuke; Yamaguchi, Hironori; Ishihara, Soichiro; Sunami, Eiji; Watanabe, Toshiaki

    2015-01-01

    Background Perianal hidradenitis suppurativa (PHS) is a chronic recurrent inflammatory disease of the apocrine glands present in the skin and soft tissue adjacent to the anus. It is often misdiagnosed or treatment is delayed, resulting in the formation of an abscess or, in the worst case, leading to sepsis. It is difficult to treat perianal lesions merged with fistulae completely due to its high recurrence rate. Therefore, we should diagnose it correctly and treat it with appropriate methods. Presentation of case We report two cases of PHS with anal fistulae that were examined preoperatively using magnetic resonance imaging (MRI) and treated safely by surgery without any recurrence. Discussion The anal sphincter area cannot be visualized and evaluated directly by fistulography. Also CT has only limited resolution, making it difficult to distinguish between soft tissues and inflammatory streaks. Endosonography is not suitable for the examination of supra-sphincteric or extra-sphincteric extensions, as it is limited by insufficient penetration of the ultrasonic beams. MRI can demonstrate the entire course of the fistulae owing to its high contrast resolution. Conclusion Our findings support the idea that PHS with complicated anal fistulae can be diagnosed accurately using MRI and treated safely and completely with surgery. PMID:26339787

  13. Magnetic resonance elastometry using a single-sided permanent magnet

    NASA Astrophysics Data System (ADS)

    Tan, Carl S.; Marble, Andrew E.; Ono, Yuu

    2012-04-01

    In this paper, we describe a magnetic resonance method of measuring material elasticity using a single-sided magnet with a permanent static field gradient. This method encodes sample velocity in a reciprocal space using Hahn spin-echoes with variable timing. The experimental results show a strong correlation between magnetic resonance signal attenuation and elasticity when an oscillating force is applied on the sample. This relationship in turn provides us with information about the displacement velocity experienced by the sample, which is inversely proportional to Young's modulus. The proposed method shows promise in offering a portable and cost-effective magnetic resonance elastography system.

  14. Magnetic resonance image guided brachytherapy.

    PubMed

    Tanderup, Kari; Viswanathan, Akila N; Kirisits, Christian; Frank, Steven J

    2014-07-01

    The application of magnetic resonance image (MRI)-guided brachytherapy has demonstrated significant growth during the past 2 decades. Clinical improvements in cervix cancer outcomes have been linked to the application of repeated MRI for identification of residual tumor volumes during radiotherapy. This has changed clinical practice in the direction of individualized dose administration, and resulted in mounting evidence of improved clinical outcome regarding local control, overall survival as well as morbidity. MRI-guided prostate high-dose-rate and low-dose-rate brachytherapies have improved the accuracy of target and organs-at-risk delineation, and the potential exists for improved dose prescription and reporting for the prostate gland and organs at risk. Furthermore, MRI-guided prostate brachytherapy has significant potential to identify prostate subvolumes and dominant lesions to allow for dose administration reflecting the differential risk of recurrence. MRI-guided brachytherapy involves advanced imaging, target concepts, and dose planning. The key issue for safe dissemination and implementation of high-quality MRI-guided brachytherapy is establishment of qualified multidisciplinary teams and strategies for training and education.

  15. [Presurgical functional magnetic resonance imaging].

    PubMed

    Stippich, C

    2010-02-01

    Functional magnetic resonance imaging (fMRI) is an important and novel neuroimaging modality for patients with brain tumors. By non-invasive measurement, localization and lateralization of brain activiation, most importantly of motor and speech function, fMRI facilitates the selection of the most appropriate and sparing treatment and function-preserving surgery. Prerequisites for the diagnostic use of fMRI are the application of dedicated clinical imaging protocols and standardization of the respective imaging procedures. The combination with diffusion tensor imaging (DTI) also enables tracking and visualization of important fiber bundles such as the pyramidal tract and the arcuate fascicle. These multimodal MR data can be implemented in computer systems for functional neuronavigation or radiation treatment. The practicability, accuracy and reliability of presurgical fMRI have been validated by large numbers of published data. However, fMRI cannot be considered as a fully established modality of diagnostic neuroimaging due to the lack of guidelines of the responsible medical associations as well as the lack of medical certification of important hardware and software components. This article reviews the current research in the field and provides practical information relevant for presurgical fMRI.

  16. Magnetic resonance imaging findings in acute canine distemper virus infection.

    PubMed

    Bathen-Noethen, A; Stein, V M; Puff, C; Baumgaertner, W; Tipold, A

    2008-09-01

    Demyelination is the prominent histopathological hallmark in the acute stage of canine distemper virus infection. Magnetic resonance imaging is an important diagnostic tool in human beings to determine demyelination in the brain, for example in multiple sclerosis. Five young dogs with clinically suspected canine distemper virus infection were subjected to magnetic resonance imaging of the brain and histopathological and immunohistochemical examinations. Hyperintense lesions and loss of contrast between grey and white matter were detected in T2-weighted images in the cerebellum and/or in the brainstem of three dogs, which correlated with demyelination demonstrated in histopathological examination. Furthermore, increased signal intensities in T2-weighted images were seen in the temporal lobe of four dogs with no evidence of demyelination. Magnetic resonance imaging seems to be a sensitive tool for the visualisation of in vivo myelination defects in dogs with acute canine distemper virus infection. Postictal oedema and accumulation of antigen positive cells have to be considered an important differential diagnosis.

  17. Wernicke encephalopathy with atypical magnetic resonance imaging.

    PubMed

    Liou, Kuang-Chung; Kuo, Shu-Fan; Chen, Lu-An

    2012-11-01

    Wernicke encephalopathy (WE) is a medical emergency caused by thiamine (vitamin B1) deficiency. Typical clinical manifestations are mental change, ataxia, and ocular abnormalities. Wernicke encephalopathy is an important differential diagnosis in all patients with acute mental change. However, the disorder is greatly underdiagnosed. Clinical suspicion, detailed history taking, and neurologic evaluations are important for early diagnosis. Magnetic resonance imaging (MRI) is currently considered the diagnostic method of choice. Typical MRI findings of WE are symmetrical involvement of medial thalamus, mammillary body, and periaqueductal gray matter. Prompt thiamine supplement is important in avoiding unfavorable outcomes. Here, we report a case of alcoholic WE with typical clinical presentation but with atypical MRI. Axial fluid-attenuated inversion recovery images showing symmetrical hyperintensity lesions in dentate nuclei of cerebellum, olivary bodies, and dorsal pons. Although atypical MRI findings are more common in nonalcoholic WE, it can also occur in alcoholic WE. This article is aimed to highlight the potential pitfalls in diagnosing acute mental change, the importance of clinical suspicion, and early treatment in WE.

  18. Magnetic resonance imaging for characterizing myocardial diseases.

    PubMed

    Saeed, Maythem; Liu, Hui; Liang, Chang-Hong; Wilson, Mark W

    2017-03-31

    The National Institute of Health defined cardiomyopathy as diseases of the heart muscle. These myocardial diseases have different etiology, structure and treatment. This review highlights the key imaging features of different myocardial diseases. It provides information on myocardial structure/orientation, perfusion, function and viability in diseases related to cardiomyopathy. The standard cardiac magnetic resonance imaging (MRI) sequences can reveal insight on left ventricular (LV) mass, volumes and regional contractile function in all types of cardiomyopathy diseases. Contrast enhanced MRI sequences allow visualization of different infarct patterns and sizes. Enhancement of myocardial inflammation and infarct (location, transmurality and pattern) on contrast enhanced MRI have been used to highlight the key differences in myocardial diseases, predict recovery of function and healing. The common feature in many forms of cardiomyopathy is the presence of diffuse-fibrosis. Currently, imaging sequences generating the most interest in cardiomyopathy include myocardial strain analysis, tissue mapping (T1, T2, T2*) and extracellular volume (ECV) estimation techniques. MRI sequences have the potential to decode the etiology by showing various patterns of infarct and diffuse fibrosis in myocarditis, amyloidosis, sarcoidosis, hypertrophic cardiomyopathy due to aortic stenosis, restrictive cardiomyopathy, arrythmogenic right ventricular dysplasia and hypertension. Integrated PET/MRI system may add in the future more information for the diagnosis and progression of cardiomyopathy diseases. With the promise of high spatial/temporal resolution and 3D coverage, MRI will be an indispensible tool in diagnosis and monitoring the benefits of new therapies designed to treat myocardial diseases.

  19. Reducing Field Distortion in Magnetic Resonance Imaging

    NASA Technical Reports Server (NTRS)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2010-01-01

    A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

  20. Could magnetic resonance provide in vivo histology?

    PubMed

    Dominietto, Marco; Rudin, Markus

    2014-01-13

    THE DIAGNOSIS OF A SUSPECTED TUMOR LESION FACES TWO BASIC PROBLEMS: detection and identification of the specific type of tumor. Radiological techniques are commonly used for the detection and localization of solid tumors. Prerequisite is a high intrinsic or enhanced contrast between normal and neoplastic tissue. Identification of the tumor type is still based on histological analysis. The result depends critically on the sampling sites, which given the inherent heterogeneity of tumors, constitutes a major limitation. Non-invasive in vivo imaging might overcome this limitation providing comprehensive three-dimensional morphological, physiological, and metabolic information as well as the possibility for longitudinal studies. In this context, magnetic resonance based techniques are quite attractive since offer at the same time high spatial resolution, unique soft tissue contrast, good temporal resolution to study dynamic processes and high chemical specificity. The goal of this paper is to review the role of magnetic resonance techniques in characterizing tumor tissue in vivo both at morphological and physiological levels. The first part of this review covers methods, which provide information on specific aspects of tumor phenotypes, considered as indicators of malignancy. These comprise measurements of the inflammatory status, neo-vascular physiology, acidosis, tumor oxygenation, and metabolism together with tissue morphology. Even if the spatial resolution is not sufficient to characterize the tumor phenotype at a cellular level, this multiparametric information might potentially be used for classification of tumors. The second part discusses mathematical tools, which allow characterizing tissue based on the acquired three-dimensional data set. In particular, methods addressing tumor heterogeneity will be highlighted. Finally, we address the potential and limitation of using MRI as a tool to provide in vivo tissue characterization.

  1. Miniature Magnet for Electron Spin Resonance Experiments

    ERIC Educational Resources Information Center

    Rupp, L. W.; And Others

    1976-01-01

    Describes commercially available permanent magnets that have been incorporated in a compact and inexpensive structure providing both field sweep and modulation suitable for electron spin resonance at microwave frequencies. (MLH)

  2. Magnetic resonance imaging of the cryptorchid testis.

    PubMed

    Landa, H M; Gylys-Morin, V; Mattrey, R F; Krous, H F; Kaplan, G W; Packer, M G

    1987-01-01

    Magnetic resonance imaging was used to evaluate seven patients with undescended testes. In six patients the presence or absence of testicular tissue was predicted correctly prior to surgery. Spermatic cord structures, if present, were accurately visualized in all patients.

  3. Coronary Computed Tomography and Magnetic Resonance Imaging

    PubMed Central

    Kantor, Birgit; Nagel, Eike; Schoenhagen, Paul; Barkhausen, Jörg; Gerber, Thomas C.

    2009-01-01

    Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use. PMID:19269527

  4. Coronary computed tomography and magnetic resonance imaging.

    PubMed

    Kantor, Birgit; Nagel, Eike; Schoenhagen, Paul; Barkhausen, Jörg; Gerber, Thomas C

    2009-04-01

    Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use.

  5. Pocket atlas of cranial magnetic resonance imaging

    SciTech Connect

    Haughton, V.M.; Daniels, D.L.

    1986-01-01

    This atlas illustrates normal cerebral anatomy in magnetic resonance images. From their studies in cerebral anatomy utilizing cryomicrotome and other techniques, the authors selected more than 100 high-resolution images that represent the most clinically useful scans.

  6. International Society for Magnetic Resonance in Medicine

    MedlinePlus

    ... Join the ISMRM Journals History & Mission Central Office Society Award Winners Strategic Plan Policies Corporate Members Contact ... E-Library Virtual Meetings Connect With Us International Society for Magnetic Resonance in Medicine 2300 Clayton Road, ...

  7. Chronic liver disease: evaluation by magnetic resonance

    SciTech Connect

    Stark, D.D.; Goldberg, H.I.; Moss, A.A.; Bass, N.M.

    1984-01-01

    Magnetic resonance (MR) imaging distinguished hepatitis from fatty liver and cirrhosis in a woman with a history of alcohol abuse. Anatomic and physiologic manifestations of portal hypertension were also demonstrated by MR.

  8. Polywater: proton nuclear magnetic resonance spectrum.

    PubMed

    Page, T F; Jakobsen, R J; Lippincott, E R

    1970-01-02

    In the presence of water, the resonance of the strongly hydrogenbonded protons characteristic of polywater appears at 5 parts per million lower applied magnetic field than water. Polywater made by a new method confirms the infrared spectrum reported originally.

  9. Evidence-based guideline recommendations on multiparametric magnetic resonance imaging in the diagnosis of prostate cancer: A Cancer Care Ontario clinical practice guideline

    PubMed Central

    Haider, Masoom A.; Yao, Xiaomei; Loblaw, Andrew; Finelli, Antonio

    2017-01-01

    This clinical guideline focuses on: 1) the use of multiparametric magnetic resonance imaging (mpMRI) in diagnosing clinically significant prostate cancer (CSPC) in patients with an elevated risk of CSPC and who are biopsy-naïve; and 2) the use of mpMRI in diagnosing CSPC in patients with a persistently elevated risk of having CSPC and who have a negative transrectal ultrasound (TRUS)-guided systematic biopsy. The methods of the Practice Guideline Development Cycle were used. MEDLINE, EMBASE, the Cochrane Library (1997‒April 2014), main guideline websites, and relevant annual meeting abstracts (2011‒2014) were searched. Internal and external reviews were conducted. The two main recommendations are: Recommendation 1: In patients with an elevated risk of CSPC (according to prostate-specific antigen [PSA] levels and/or nomograms) who are biopsy-naïve: mpMRI followed by targeted biopsy (biopsy directed at cancer-suspicious foci detected with mpMRI) should not be considered the standard of care.Data from future research studies are essential and should receive high-impact trial funding to determine the value of mpMRI in this clinical context.Recommendation 2: In patients who had a prior negative TRUS-guided systematic biopsy and demonstrate an increasing risk of having CSPC since prior biopsy (e.g., continued rise in PSA and/or change in findings from digital rectal examination): mpMRI followed by targeted biopsy may be considered to help in detecting more CSPC patients compared with repeated TRUS-guided systematic biopsy. PMID:28163805

  10. Computed tomography and magnetic resonance diagnosis of variations in the anatomical location of the major salivary glands in 1680 dogs and 187 cats.

    PubMed

    Durand, A; Finck, M; Sullivan, M; Hammond, G

    2016-03-01

    During assessment of routine clinical magnetic resonance imaging (MRI) of the heads of dogs, variations in the location of mandibular and zygomatic salivary glands (SGs) were observed incidentally. The aims of this retrospective study were to describe anatomical variations of the major SGs found on MRI and computed tomography (CT) studies of the head in dogs and cats and to investigate possible clinical relevancy. No anatomical variation of the SGs was seen in cats, but in dogs, although variation of the parotid SG was not identified, that of the mandibular SG was found in 33/1680 animals (2%), either unilaterally (6/33 right-sided, 13/33 left-sided) or bilaterally (14/33). The Border terrier breed (19/33, 58%) was over-represented. Each atypically located mandibular SG was positioned medial to the digastric muscle and rostral to the retropharyngeal lymph node. The sublingual glands were difficult to delineate from the mandibular glands. Anatomical variation of one zygomatic gland (3/4 left-sided) was identified in four small-breed dogs (0.2%). Each atypically located zygomatic gland was tilted at the ventrorostral aspect of the masseter muscle underneath the skin surface. MRI and CT characteristics were not different between typically and atypically located SGs. None of the dogs had clinical signs related with SG disease. It was concluded that, with suspected breed predispositions, incidental unilateral or bilateral anatomical variations of mandibular and zygomatic SGs can be encountered in dogs and an awareness of these possible variations may be important in pre-surgical planning.

  11. Single Nuclear Spin Magnetic Resonance Force Microscopy

    DTIC Science & Technology

    2010-05-02

    Lab. In work not directly supported by this grant, these projects advanced MRFM detected Ferromagnetic Resonance ( FMR ) to enable studies of...directly supported by this grant, these projects advanced MRFM detected Ferromagnetic Resonance ( FMR ) to enable studies of submicron magnetic structures...our earlier NMR detection of 19F spins in CaF2 we have conducted 65Cu, 63Cu NMR stud- ies for studies of interface phenomena in multilayered magnetic

  12. Torque-mixing Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan; Diao, Zhu; Belov, Miro; Burgess, Jacob; Compton, Shawn; Hiebert, Wayne; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory; Thomson, Douglas; Freeman, Mark

    A universal, mechanical torque method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by induction, a signal proportional to the transverse component of a precessing dipole moment can be measured as a pure mechanical torque in broadband, frequency-swept spectroscopy. Comprehensive electron spin resonance of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature are presented to demonstrate the method. The rich detail allows analysis of even complex 3D spin textures.

  13. Magnetic resonance force detection using a membrane resonator

    NASA Astrophysics Data System (ADS)

    Scozzaro, N.; Ruchotzke, W.; Belding, A.; Cardellino, J.; Blomberg, E. C.; McCullian, B. A.; Bhallamudi, V. P.; Pelekhov, D. V.; Hammel, P. C.

    2016-10-01

    The availability of compact, low-cost magnetic resonance imaging instruments would further broaden the substantial impact of this technology. We report highly sensitive detection of magnetic resonance using low-stress silicon nitride (SiNx) membranes. We use these membranes as low-loss, high-frequency mechanical oscillators and find they are able to mechanically detect spin-dependent forces with high sensitivity enabling ultrasensitive magnetic resonance detection. The high force detection sensitivity stems from their high mechanical quality factor Q ∼106 [1,2] combined with the low mass of the resonator. We use this excellent mechanical force sensitivity to detect the electron spin magnetic resonance using a SiNx membrane as a force detector. The demonstrated force sensitivity at 300 K is 4 fN/√{Hz } , indicating a potential low temperature (4 K) sensitivity of 25 aN/√{Hz } . Given their sensitivity, robust construction, large surface area and low cost, SiNx membranes can potentially serve as the central component of a compact room-temperature ESR and NMR instrument having spatial resolution superior to conventional approaches.

  14. Magnetic Resonance Imaging (MRI) Safety

    MedlinePlus

    ... radiation. Instead, MRI uses a powerful magnetic field, radio waves, rapidly changing magnetic fields, and a computer to ... in most of the body's tissues. The applied radio waves then cause these protons to produce signals that ...

  15. Advanced and Conventional Magnetic Resonance Imaging in Neuropsychiatric Lupus

    PubMed Central

    Sarbu, Nicolae; Bargalló, Núria; Cervera, Ricard

    2015-01-01

    Neuropsychiatric lupus is a major diagnostic challenge, and a main cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Magnetic resonance imaging (MRI) is, by far, the main tool for assessing the brain in this disease. Conventional and advanced MRI techniques are used to help establishing the diagnosis, to rule out alternative diagnoses, and recently, to monitor the evolution of the disease. This review explores the neuroimaging findings in SLE, including the recent advances in new MRI methods. PMID:26236469

  16. Magnetic Resonance Characterization of Axonal Response to Spinal Cord Injury

    DTIC Science & Technology

    2014-10-01

    proper diagnosis and treatment. Magnetic resonance imaging ( MRI ) is routinely performed in patients and provides valuable information about cord edema and...novel MRI methods to the problem of assessment of axonal loss, axonal diameter distribution, and myelin loss (q-space imaging (QSI) and ultra-short...echo-time (UTE) MRI ) first on animal specimens and then on human subjects. During the final period of the project the focus of the research was on the

  17. Investigation of laser polarized xenon magnetic resonance

    NASA Technical Reports Server (NTRS)

    Walsworth, Ronald L.

    1998-01-01

    Ground-based investigations of a new biomedical diagnostic technology: nuclear magnetic resonance of laser polarized noble gas are addressed. The specific research tasks discussed are: (1) Development of a large-scale noble gas polarization system; (2) biomedical investigations using laser polarized noble gas in conventional (high magnetic field) NMR systems; and (3) the development and application of a low magnetic field system for laser polarized noble gas NMR.

  18. Coherence of magnetic resonators in a metamaterial

    SciTech Connect

    Hou, Yumin

    2013-12-15

    The coherence of periodic magnetic resonators (MRs) under oblique incidence is studied using simulations. The correlated phase of interaction including both the retardation effect and relative phase difference between two MRs is defined, and it plays a key role in the MR interaction. The correlated phase is anisotropic, as is the coherence condition. The coherence condition is the same as the Wood's anomaly and verified by the Fano resonance. This study shows that the applications of the Fano resonance of periodic MRs will become widespread owing to achieving the Fano resonance simply by tuning the incident angle.

  19. Nuclear Magnetic Resonance Technology for Medical Studies

    NASA Astrophysics Data System (ADS)

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-10-01

    Nuclear magnetic resonance proton imaging provides anatomical definition of normal and abnormal tissues with a contrast and detection sensitivity superior to those of x-ray computed tomography in the human head and pelvis and parts of the cardiovascular and musculoskeletal systems. Recent improvements in technology should lead to advances in diagnostic imaging of the breast and regions of the abdomen. Selected-region nuclear magnetic resonance spectroscopy of protons, carbon-13, and phosphorus-31 has developed into a basic science tool for in vivo studies on man and a unique tool for clinical diagnoses of metabolic disorders. At present, nuclear magnetic resonance is considered safe if access to the magnet environment is controlled. Technological advances employing field strengths over 2 teslas will require biophysical studies of heating and static field effects.

  20. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-07-01

    Several demonstrations of resonance phenomena associated with nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are described. The demonstrations comprise common orienteering compasses, whose needles represent magnetic dipoles, along with three collinear permanent magnets and a magnetic stir plate or pulseable electromagnets. The trio of permanent magnets provides a laterally uniform magnetic field, whose strength decreases with distance from the magnets. Resonance can be observed by adjusting the frequency of the magnetic stirrer to match the resonant frequency of the compass needle, which is shown to depend on magnetic field strength, that is, the needle's position relative to the permanent magnets. Another demonstration involves pulsing electromagnets that apply a perpendicular magnetic field that causes the compass needles to oscillate. The effects of shielding, spin-spin coupling, magnetogyric ratio, and free induction decay can also be demonstrated. By moving the trio of permanent magnets relative to the compasses, the MRI experiment can be mimicked. Complete instructions for the construction of the demonstrations, which can be used on an overhead projector, are included.

  1. Magnetic nanoparticles in magnetic resonance imaging and diagnostics.

    PubMed

    Rümenapp, Christine; Gleich, Bernhard; Haase, Axel

    2012-05-01

    Magnetic nanoparticles are useful as contrast agents for magnetic resonance imaging (MRI). Paramagnetic contrast agents have been used for a long time, but more recently superparamagnetic iron oxide nanoparticles (SPIOs) have been discovered to influence MRI contrast as well. In contrast to paramagnetic contrast agents, SPIOs can be functionalized and size-tailored in order to adapt to various kinds of soft tissues. Although both types of contrast agents have a inducible magnetization, their mechanisms of influence on spin-spin and spin-lattice relaxation of protons are different. A special emphasis on the basic magnetism of nanoparticles and their structures as well as on the principle of nuclear magnetic resonance is made. Examples of different contrast-enhanced magnetic resonance images are given. The potential use of magnetic nanoparticles as diagnostic tracers is explored. Additionally, SPIOs can be used in diagnostic magnetic resonance, since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.

  2. Magnetic resonance imaging: present and future applications

    PubMed Central

    Johnston, Donald L.; Liu, Peter; Wismer, Gary L.; Rosen, Bruce R.; Stark, David D.; New, Paul F.J.; Okada, Robert D.; Brady, Thomas J.

    1985-01-01

    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. ImagesFig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13Fig. 14 PMID:3884120

  3. Magnetic resonance imaging structured reporting in infertility.

    PubMed

    Montoliu-Fornas, Guillermina; Martí-Bonmatí, Luis

    2016-06-01

    Our objective was to define and propose a standardized magnetic resonance (MR) imaging structured report in patients with infertility to have clinical completeness on possible diagnosis and severity. Patients should be studied preferable on 3T equipment with a surface coil. Standard MR protocol should include high-resolution fast spin-echo T2-weighted, diffusion-weighted images and gradient-echo T1-weighted fat suppression images. The report should include ovaries (polycystic, endometrioma, tumor), oviduct (hydrosalpinx, hematosalpinx, pyosalpinx, peritubal anomalies), uterus (agenesia, hypoplasia, unicornuate, uterus didelphys, bicornuate, septate uterus), myometrium (leiomyomas, adenomyosis), endometrium (polyps, synechia, atrophy, neoplasia), cervix and vagina (isthmoceles, mucosal-parietal irregularity, stenosis, neoplasia), peritoneum (deep endometriosis), and urinary system-associated abnormalities. To be clinically useful, radiology reports must be structured, use standardized terminology, and convey actionable information. The structured report must comprise complete, comprehensive, and accurate information, allowing radiologists to continuously interact with patients and referring physicians to confirm that the information is used properly to affect the decision making process.

  4. Fetal magnetic resonance imaging in obstetric practice.

    PubMed

    Köşüş, Aydın; Köşüş, Nermin; Usluoğulları, Betül; Duran, Müzeyyen; Turhan, Nilgün Öztürk; Tekşam, Mehmet

    2011-01-01

    Ultrasonography (USG) is the primary imaging method for prenatal diagnosis of fetal abnormalities since its discovery. Although it is the primary method of fetal imaging, it cannot provide sufficient information about the fetus in some conditions such as maternal obesity, oligohydramnios and engagement of the fetal head. At this stage, magnetic resonance imaging (MRI) facilitates examination by providing more specific information. The need and importance of fetal MRI applications further increased by the intrauterine surgery which is currently gaining popularity. Some advantages of fetal MRI over USG are the good texture of contrast, a greater study area and visualization of the lesion and neighbourhood relations, independence of the operators. Also it is not affected by maternal obesity and severe oligohydramnios. However, MRI is inadequate in detecting fetal limb and cardiac abnormalities when compared to USG. MRI is not used routinely in pregnancy. It is used in situations where nonionizing imaging methods are inadequate or ionizing radiation is required in pregnant women. It is not recommended during the first trimester. Contrast agent (Godalinium) is not used during pregnancy. It is believed that MRI is not harmful to the fetus, although the biological risk of MRI application is not known. MRI technique is superior to USG in the detection of corpus callosum dysgenesis, third-trimester evaluation of posterior fossa malformations, bilateral renal agenesis, diaphragmatic hernia and assessment of lung maturation. Especially, it is the method of choice for evaluation of central nervous system (CNS) abnormalities. Fetal MRI has a complementary role with USG. It provides important information for prenatal diagnosis, increases diagnostic accuracy, and in turn affects the prenatal treatment, prenatal interventions and birth plan.

  5. Pediatric obesity phenotyping by magnetic resonance methods

    PubMed Central

    Shen, Wei; Liu, Haiying; Punyanitya, Mark; Chen, Jun; Heymsfield, Steven B.

    2007-01-01

    Purpose of review Accurate measurement of adiposity in obese children is required for characterizing the condition’s phenotype, severity, and treatment effects in vivo. Non-invasive and safe, magnetic resonance imaging and spectroscopy provide an important new approach for characterizing key aspects of pediatric obesity. This review focuses on recent advances in non-invasive magnetic resonance imaging and spectroscopy for quantifying total body and regional adiposity, mapping adipose tissue distribution, and evaluating selected metabolic disturbances in children. The aim is to provide an investigator-focused overview of magnetic resonance methods for use in the study of pediatric body composition and metabolism. Recent findings Whole body axial images can be rapidly acquired on most clinical magnetic resonance imaging scanners. The images can then be semi-automatically segmented into subcutaneous, visceral, and intramuscular adipose tissue. Specific pediatric studies of errors related to slice gap and number are available. The acquisition of scans in healthy and premature infants is now feasible with recent technological advances. Spectroscopic, Dixon, and other approaches can be used to quantify the lipid content of liver, skeletal muscle, and other organs. Protocol selection is based on factors such as subject age and cost. Particular attention should be directed towards identification of landmarks in growth studies. Recent advances promise to reduce the requirement of subjects to remain motionless for relatively long periods. Summary Magnetic resonance imaging and spectroscopy are safe, practical, and widely available methods for phenotyping adiposity in children that open new opportunities for metabolism and nutritional research. PMID:16205458

  6. Magnetic resonance imaging in cardiac amyloidosis

    SciTech Connect

    O'Donnell, J.K.; Go, R.T.; Bott-Silverman, C.; Feiglin, D.H.; Salcedo, E.; MacIntyre, W.J.

    1984-01-01

    Primary amyloidosis (AL) involves the myocardium in 90% of cases and may present as apparent ischemia, vascular disease, or congestive heart failure. Two-dimensional echocardiography (echo) has proven useful in the diagnosis, particularly in differentiating AL from constrictive pericarditis. The findings of thickened RV and LV myocardium, normal LV cavity dimension, and a diffuse hyperrefractile ''granular sparkling'' appearance are virtually diagnostic. Magnetic resonance (MR) imaging may improve the resolution of anatomic changes seen in cardiac AL and has the potential to provide more specific information based on biochemical tissue alterations. In this preliminary study, the authors obtained both MR and echo images in six patients with AL and biopsy-proven myocardial involvement. 5/6 patients also had Tc-99 PYP myocardial studies including emission tomography (SPECT). MR studies utilized a 0.6 Tesla superconductive magnet. End diastolic gated images were obtained with TE=30msec and TR=R-R interval on the ECG. 6/6 pts. showed LV wall thickening which was concentric and included the septum. Papillary muscles were identified in all and were enlarged in 3/6. 4/6 pts. showed RV wall thickening but to a lesser degree than LV. Pericardial effusions were present in 4 cases. These findings correlated well with the results of echo although MR gave better RV free wall resolution. PYP scans were positive in 3 pts. but there was no correlation with degree of LV thickening. The authors conclude that there are no identifiable MR findings in patients with cardiac AL which encourage further attempts to characterize myocardial involvement by measurement of MR relaxation times in vivo.

  7. Is there an association between clinical features, response to diagnostic analgesia and radiological findings in horses with a magnetic resonance imaging diagnosis of navicular disease or other injuries of the podotrochlear apparatus?

    PubMed

    Parkes, Rebecca; Newton, Richard; Dyson, Sue

    2015-04-01

    Previous descriptions of the clinical features of navicular disease occurred before the widespread use of magnetic resonance imaging (MRI) allowed a more definitive diagnosis of foot pain. The objective of this study was to compare the clinical features of horses with lesions of the podotrochlear apparatus with those with other causes of foot pain. It was hypothesised that primary navicular bone disease would be associated with more advanced radiological findings than other diagnoses. A retrospective study was performed of all horses examined at a referral centre with a definitive diagnosis of foot pain based on MRI ± post-mortem examination. Clinical examination findings, response to diagnostic analgesia and radiological grading of the navicular bone were compared among five diagnosis groups: (1) primary navicular bone pathology (NB); (2) lesions of the collateral sesamoidean ligament and/or distal sesamoidean impar ligament (CSL + DSIL); (3) primary deep digital flexor tendon injury (DDFT); (4) navicular bone pathology and other lesions of the podotrochlear apparatus ± DDFT (PTA) and (5) Other. There were 702 horses (NB, 62; CSL + DSIL, 180; DDFT, 69; PTA, 92; Other, 299). Horses with PTA injuries were more frequently unilaterally lame than other groups (P = 0.04). Horses with DDFT injury were more likely to exhibit pain on turning than other groups (P <0.01). There were no associations between response to diagnostic analgesia and diagnostic group, and no association between radiological grade and diagnostic group. Clinical examination findings generally did not discriminate between diseases of the PTA and other causes of foot pain. Overall radiological scores of the navicular bone did not accurately predict navicular bone pathology.

  8. Magnetic material arrangement in oriented termites: a magnetic resonance study

    NASA Astrophysics Data System (ADS)

    Alves, O. C.; Wajnberg, E.; de Oliveira, J. F.; Esquivel, D. M. S.

    2004-06-01

    Temperature dependence of the magnetic resonance is used to study the magnetic material in oriented Neocapritermes opacus (N.o.) termite, the only prey of the migratory ant Pachycondyla marginata (P.m.). A broad line in the g=2 region, associated to isolated nanoparticles shows that at least 97% of the magnetic material is in the termite's body (abdomen + thorax). From the temperature dependence of the resonant field and from the spectral linewidths, we estimate the existence of magnetic nanoparticles 18.5 ± 0.3 nm in diameter and an effective magnetic anisotropy constant, Keff between 2.1 and 3.2 × 10 4 erg/cm 3. A sudden change in the double integrated spectra at about 100 K for N.o. with the long body axis oriented perpendicular to the magnetic field can be attributed to the Verwey transition, and suggests an organized film-like particle system.

  9. Gadofosveset-enhanced magnetic resonance angiography

    PubMed Central

    Goyen, Mathias

    2008-01-01

    Gadofosveset (Vasovist®, Bayer Schering Pharma AG, Berlin/Germany) is the first intravascular contrast agent approved for use with magnetic resonance angiography in the European Union, Switzerland, Turkey, Canada, and Australia. Gadofosveset reversibly binds to albumin providing extended intravascular enhancement compared wth existing extracellular magnetic resonance contrast agents. Prior to approval, gadofosveset underwent extensive testing to evaluate the safety and efficacy of the drug; the clinical trials show that gadofosveset-enhanced magnetic resonance angiography (MRA) is safe and well tolerated in patients with vascular disease and effective for the detection of vascular stenosis and aneurysms gadofosveset has the potential to open new horizons in diagnostic MRA by increasing the spatial resolution and the robustness of MRA examinations and facilitating the examination of multiple vascular beds. PMID:18629367

  10. Magnetic resonance imaging of the body

    SciTech Connect

    Higgins, C.B.; Hricak, H.

    1987-01-01

    This text provides reference to magnetic resonance imaging (MRI) of the body. Beginning with explanatory chapters on the physics, instrumentation, and interpretation of MRI, it proceeds to the normal anatomy of the neck, thorax, abdomen, and pelvis. Other chapters cover magnetic resonance imaging of blood flow, the larynx, the lymph nodes, and the spine, as well as MRI in obstetrics. The text features detailed coverage of magnetic resonance imaging of numerous disorders and disease states, including neck disease, thoracic disease; breast disease; congenital and acquired heart disease; vascular disease; diseases of the liver, pancreas, and spleen; diseases of the kidney, adrenals, and retroperitoneum; diseases of the male and female pelvis; and musculoskeletal diseases. Chapters on the biological and environmental hazards of MRI, the current clinical status of MRI in comparison to other imaging modalities, and economic considerations are also included.

  11. Tutte polynomial in functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    García-Castillón, Marlly V.

    2015-09-01

    Methods of graph theory are applied to the processing of functional magnetic resonance images. Specifically the Tutte polynomial is used to analyze such kind of images. Functional Magnetic Resonance Imaging provide us connectivity networks in the brain which are represented by graphs and the Tutte polynomial will be applied. The problem of computing the Tutte polynomial for a given graph is #P-hard even for planar graphs. For a practical application the maple packages "GraphTheory" and "SpecialGraphs" will be used. We will consider certain diagram which is depicting functional connectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The Tutte polynomial for the resulting neural networks will be computed and some numerical invariants for such network will be obtained. Our results show that the Tutte polynomial is a powerful tool to analyze and characterize the networks obtained from functional magnetic resonance imaging.

  12. Magnetic Resonance Imaging (MRI) - Spine

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  13. Children's (Pediatric) Magnetic Resonance Imaging

    MedlinePlus

    ... if your child has any implanted medical or electronic devices. Inform your doctor and the technologist prior ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ...

  14. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePlus

    ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  15. Magnetic Resonance Imaging (MRI) Safety

    MedlinePlus

    ... by a receiver within the MR scanner. The signals are specially characterized using the rapidly changing magnetic field, and, with the help of computer processing, images of tissues are created as "slices" that ...

  16. Magnetic resonance imaging of ductus arteriosus Botalli apertus in adulthood.

    PubMed

    Schmidt, M; Theissen, P; Deutsch, H J; Erdmann, E; Schicha, H

    1999-02-28

    Ductus arteriosus Botalli apertus is a congenital cardiovascular malformation usually diagnosed in childhood by echocardiography and/or cardiac catheterization. Reports about magnetic resonance imaging of ductus arteriosus Botalli apertus are rare. We report about three adult female patients and one adult male patient in whom magnetic resonance imaging was able to demonstrate the pathology. In all four patients quantitative data about right ventricular function were calculated. Pulmonary hypertension with Eisenmenger syndrome detected by cardiac catheterization had developed in three of the four patients excluding operative closure of the ductus. The patient in whom pulmonary hypertension had not developed underwent successful operative closure of the ductus. Magnetic resonance imaging is a non-invasive tool that can be used for diagnosis of ductus arteriosus Botalli apertus and it allows to quantify right ventricular function. Magnetic resonance imaging can be used repetitively in patients with Eisenmenger syndrome which may be helpful for better timing of combined heart-lung transplantation as ultimate therapeutic strategy because deterioration of right ventricular function can be monitored.

  17. Development of the 1.2 T~1.5 T Permanent Magnetic Resonance Imaging Device and Its Application for Mouse Imaging.

    PubMed

    Wang, Guangxin; Xie, Huantong; Hou, Shulian; Chen, Wei; Zhao, Qiang; Li, Shiyu

    2015-01-01

    By improving the main magnet, gradient, and RF coils design technology, manufacturing methods, and inventing new magnetic resonance imaging (MRI) special alloy, a cost-effective and small animal specific permanent magnet-type three-dimensional magnetic resonance imager was developed. The main magnetic field strength of magnetic resonance imager with independent intellectual property rights is 1.2~1.5 T. To demonstrate its effectiveness and validate the mouse imaging experiments in different directions, we compared the images obtained by small animal specific permanent magnet-type three-dimensional magnetic resonance imager with that obtained by using superconductor magnetic resonance imager for clinical diagnosis.

  18. Granular convection observed by magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Ehrichs, E. E.; Jaeger, H. M.; Karczmar, Greg S.; Knight, James B.; Kuperman, Vadim Yu.; Nagel, Sidney R.

    1995-03-01

    Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here.

  19. Granular convection observed by magnetic resonance imaging

    SciTech Connect

    Ehrichs, E.E.; Jaeger, H.M.; Knight, J.B.; Nagel, S.R.; Karczmar, G.S.; Kuperman, V.Yu.

    1995-03-17

    Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here. 31 refs., 4 figs.

  20. Magnetic resonance neurography of the brachial plexus

    PubMed Central

    Upadhyaya, Vaishali; Upadhyaya, Divya Narain; Kumar, Adarsh; Pandey, Ashok Kumar; Gujral, Ratni; Singh, Arun Kumar

    2015-01-01

    Magnetic Resonance Imaging (MRI) is being increasingly recognised all over the world as the imaging modality of choice for brachial plexus and peripheral nerve lesions. Recent refinements in MRI protocols have helped in imaging nerve tissue with greater clarity thereby helping in the identification, localisation and classification of nerve lesions with greater confidence than was possible till now. This article on Magnetic Resonance Neurography (MRN) is based on the authors’ experience of imaging the brachial plexus and peripheral nerves using these protocols over the last several years. PMID:26424974

  1. Cardiovascular magnetic resonance of anomalous coronary arteries.

    PubMed

    Varghese, Anitha; Keegan, Jennifer; Pennell, Dudley J

    2005-09-01

    Cardiovascular magnetic resonance of anomalous coronary arteries is a class I indication. The term anomalous coronary artery encompasses those with an abnormal origin (from the incorrect sinus, too-high or too-low from the correct sinus, or from the pulmonary artery) and/or number of ostia. Their clinical significance results from the increased risk of myocardial infarction and sudden cardiac death associated with those traversing an interarterial course between the aorta and main pulmonary artery/right ventricular outflow tract. In this article, we review the role and practice of cardiovascular magnetic resonance in this field.

  2. Magnetic force microscopy using tip magnetization modulated by ferromagnetic resonance.

    PubMed

    Arima, Eiji; Naitoh, Yoshitaka; Li, Yan Jun; Yoshimura, Satoru; Saito, Hitoshi; Nomura, Hikaru; Nakatani, Ryoichi; Sugawara, Yasuhiro

    2015-03-27

    In magnetic force microscopy (MFM), the tip-sample distance should be reduced to analyze the microscopic magnetic domain structure with high spatial resolution. However, achieving a small tip-sample distance has been difficult because of superimposition of interaction forces such as van der Waals and electrostatic forces induced by the sample surface. In this study, we propose a new method of MFM using ferromagnetic resonance (FMR) to extract only the magnetic field near the sample surface. In this method, the magnetization of a magnetic cantilever is modulated by FMR to separate the magnetic field and topographic structure. We demonstrate the modulation of the magnetization of the cantilever and the identification of the polarities of a perpendicular magnetic medium.

  3. Magnetic elliptical polarization of Schumann resonances

    NASA Technical Reports Server (NTRS)

    Sentman, D. D.

    1987-01-01

    Measurements of orthogonal, horizontal components of the magnetic field in the ELF range obtained during September 1985 show that the Schumann resonance eigenfrequencies determined separately for the north-south and east-west magnetic components differ by as much as 0.5 Hz, suggesting that the underlying magnetic signal is not linearly polarized at such times. The high degree of magnetic ellipticity found suggests that the side multiplets of the Schumann resonances corresponding to azimuthally inhomogeneous normal modes are strongly excited in the highly asymmetric earth-ionosphere cavity. The dominant sense of polarization over the measurement passband is found to be right-handed during local daylight hours, and to be left-handed during local nighttime hours.

  4. Magnetic resonance microscopy in biomedical research.

    PubMed

    Serša, I

    2012-01-01

    Magnetic resonance (MR) microscopy is a special modality of MRI with an emphasis on high spatial resolution. While its main principle is identical to conventional clinical MRI, there are several differences between the two that are mainly associated with a use of stronger magnets and gradients. MR microscopy has numerous interesting applications in material and bio sciences in which high spatial resolution is demanded and long experiment times are allowed.

  5. The reversed internal magnet of cochlear implant after magnetic resonance imaging.

    PubMed

    Kong, Soo-Keun; Oh, Se-Joon; Lee, Il-Woo; Goh, Eui-Kyung

    2014-01-01

    Cochlear implants (CI) have now become a standard method of treating severe to profound hearing loss. Recently, the number of patients with CI has been rapidly increasing as the big benefits of CI become more widely known. Magnetic resonance imaging (MRI) has also become a routine diagnostic imaging modality, used in the diagnosis of common conditions, including stroke, back pain, and headache. We report our recent experience with a case in which internal magnet of the cochlear implant was reversed after 1.5-T lumbar spine MRI. This complication is managed successfully by reversing the orientation of the external magnet in the head coil.

  6. Enhancement of artificial magnetism via resonant bianisotropy

    PubMed Central

    Markovich, Dmitry; Baryshnikova, Kseniia; Shalin, Alexander; Samusev, Anton; Krasnok, Alexander; Belov, Pavel; Ginzburg, Pavel

    2016-01-01

    All-dielectric “magnetic light” nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here an approach for enhancing of magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of the magnetic moment, tailoring the latter in the dynamical range of 100% and delivering enhancement up to 36% relative to performances of standalone spherical particles. The proposed approach provides pathways for designs of all-dielectric metamaterials and metasurfaces with strong magnetic responses. PMID:26941126

  7. Magnetic resonance imaging in neurocysticercosis.

    PubMed

    Hernández, Rosa Delia Delgado; Durán, Bernando Boleaga; Lujambio, Perla Salgado

    2014-06-01

    Cysticercosis in one of the most common parasitic infections in the central nervous system. The complex and unpredictable nature of the host immune reaction against cysticercosis as well as the pleomorphism of your injuries make the disease neurocysticercosis interesting and fascinating to study. Imaging studies play an important role in the diagnosis of this disease. Advanced imaging techniques have improved detection and visualization of scolex cysts extraparenchymal spaces.

  8. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

    Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Caprihan, Arvind; Barrow, Ranee; Yeo, Ronald A.

    2009-01-01

    Proton magnetic resonance spectroscopy ([to the first power]H-MRS) is a technique for the assay of brain neurochemistry "in vivo." N-acetylaspartate (NAA), the most prominent metabolite visible within the [to the first power]H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA-cognition…

  9. Giant infantile gliosarcoma: magnetic resonance imaging findings.

    PubMed

    Sanal, Hatice Tuba; Bulakbasi, Nail; Kocaoglu, Murat; Onguru, Onder; Chen, Lina

    2008-08-01

    Gliosarcoma is an uncommon variant of glioblastoma multiforme, which is composed of gliomatous and sarcomatous elements. The tumor is rarely encountered in childhood. This case report presents the magnetic resonance imaging characteristics of a giant gliosarcoma in a 3-year-old girl. Size and location of the tumor are described.

  10. Sample spinner for nuclear magnetic resonance spectrometer

    SciTech Connect

    Stejskal, E.O.

    1984-05-01

    A sample spinner for a nuclear magnetic resonance spectrometer having improved operating characteristics is described comprising a rotor supported at both ends by support gas bearings and positioned by a thrust gas bearing. Improved support gas bearings are also described which result in a spinner exhibiting long-term stable operation characteristics.

  11. An improved nuclear magnetic resonance spectrometer

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Manatt, S. L.

    1967-01-01

    Cylindrical sample container provides a high degree of nuclear stabilization to a nuclear magnetic resonance /nmr/ spectrometer. It is placed coaxially about the nmr insert and contains reference sample that gives a signal suitable for locking the field and frequency of an nmr spectrometer with a simple audio modulation system.

  12. Nuclear Magnetic Resonance Technology for Medical Studies.

    ERIC Educational Resources Information Center

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-01-01

    Reports on the status of nuclear magnetic resonance (NMR) from theoretical and clinical perspectives, reviewing NMR theory and relaxation parameters relevant to NMR imaging. Also reviews literature related to modern imaging strategies, signal-to-noise ratio, contrast agents, in vivo spectroscopy, spectroscopic imaging, clinical applications, and…

  13. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Bansal, Ravi; Gerber, Andrew J.; Peterson, Bradley S.

    2008-01-01

    The efficacy of anatomical magnetic resonance imaging (MRI) in studying the morphological features of various regions of the brain is described, also providing the steps used in the processing and studying of the images. The ability to correlate these features with several clinical and psychological measures can help in using anatomical MRI to…

  14. Magnetic Resonance Imaging in Biomedical Engineering

    NASA Astrophysics Data System (ADS)

    Kaśpar, Jan; Hána, Karel; Smrčka, Pavel; Brada, Jiří; Beneš, Jiří; Šunka, Pavel

    2007-11-01

    The basic principles of magnetic resonance imaging covering physical principles and basic imaging techniques will be presented as a strong tool in biomedical engineering. Several applications of MRI in biomedical research practiced at the MRI laboratory of the FBMI CTU including other laboratory instruments and activities are introduced.

  15. Isotropic anomalous filtering in Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    da S Senra Filho, Antonio Carlos; Jinzenji Duque, Juliano; Murta Junior, Luiz Otávio

    2013-01-01

    Noise is inherent to Diffusion-Weighted Magnetic Resonance Imaging (DWI) and noise reduction methods are necessary. Although process based on classical diffusion is one of the most used approaches for digital image, anomalous diffusion has the potential for image enhancement and it has not been tested for DWI noise reduction. This study evaluates Anomalous Diffusion (AD) filter as DWI enhancement method. The proposed method was applied to magnetic resonance diffusion weighted images (DW-MRI) with different noise levels. Results show better performance for anomalous diffusion when compared to classical diffusion approach. The proposed method has shown potential in DWI enhancement and can be an important process to improve quality in DWI for neuroimage-based diagnosis.

  16. Functional magnetic resonance imaging in oncology: state of the art.

    PubMed

    Guimaraes, Marcos Duarte; Schuch, Alice; Hochhegger, Bruno; Gross, Jefferson Luiz; Chojniak, Rubens; Marchiori, Edson

    2014-01-01

    In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate.

  17. Functional magnetic resonance imaging in oncology: state of the art*

    PubMed Central

    Guimaraes, Marcos Duarte; Schuch, Alice; Hochhegger, Bruno; Gross, Jefferson Luiz; Chojniak, Rubens; Marchiori, Edson

    2014-01-01

    In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate. PMID:25741058

  18. Cardiovascular Magnetic Resonance Myocardial Feature Tracking: Concepts and Clinical Applications.

    PubMed

    Schuster, Andreas; Hor, Kan N; Kowallick, Johannes T; Beerbaum, Philipp; Kutty, Shelby

    2016-04-01

    Heart failure-induced cardiovascular morbidity and mortality constitute a major health problem worldwide and result from diverse pathogeneses, including coronary artery disease, nonischemic cardiomyopathies, and arrhythmias. Assessment of cardiovascular performance is important for early diagnosis and accurate management of patients at risk of heart failure. During the past decade, cardiovascular magnetic resonance myocardial feature tracking has emerged as a useful tool for the quantitative evaluation of cardiovascular function. The method allows quantification of biatrial and biventricular mechanics from measures of deformation: strain, torsion, and dyssynchrony. The purpose of this article is to review the basic principles, clinical applications, accuracy, and reproducibility of cardiovascular magnetic resonance myocardial feature tracking, highlighting the prognostic implications. It will also provide an outlook on how this field might evolve in the future.

  19. Optimal magnetic resonance imaging of the brain.

    PubMed

    Robertson, Ian

    2011-01-01

    Quality magnetic resonance (MR) imaging is complex and requires optimization of many technical factors. The most important factors are: magnet field and gradient strengths, coil selection, receiver bandwidth, field of view and image matrix size, number of excitations, slice thickness, image weighting and contrast, imaging planes and the direction of the phase, and frequency gradients. The ability to augment a standard MR study with additional sequences, and the need to ensure the completed study is comprehensive and robust must be balanced against the time the patient spends under anesthesia in the magnet.

  20. [The surgical treatment of inflammatory aneurysms of the abdominal aorta. The usefulness of nuclear magnetic resonance (MR) in the preoperative diagnosis].

    PubMed

    Chiesa, R; Esposito, G; Melissano, G; Jannello, A; Mellone, R; Castrucci, M; Radice, F; Del Maschio, A

    1993-09-15

    Inflammatory abdominal aortic aneurysms (IAAA) represent a peculiar variant compared with the common atherosclerotic origin of aortic aneurysms. Between January 1988 and March 1992, 111 aneurysmectomies were performed at our institution: 98 elective and 13 emergency procedures. In 10 cases (all males, mean age 68.5) an IAAA was found. 8/10 of those patients operated upon electively were studied preoperatively with MRI. All the IAAA but one were correctly identified preoperatively. Identification of IAAA with MRI in these cases improved the surgical approach. In conclusion, patients with IAAA can be operated upon safely especially if a preoperative diagnosis is present. MRI greatly improves our ability to characterize non invasively IAAA.

  1. Magnetic resonance investigation of magnetic-labeled baker's yeast cells

    NASA Astrophysics Data System (ADS)

    Godoy Morais, J. P. M.; Azevedo, R. B.; Silva, L. P.; Lacava, Z. G. M.; Báo, S. N.; Silva, O.; Pelegrini, F.; Gansau, C.; Buske, N.; Safarik, I.; Safarikova, M.; Morais, P. C.

    2004-05-01

    In this study, the interaction of DMSA-coated magnetite nanoparticles (5 and 10 nm core-size) with Saccharomyces cerevisae was investigated using magnetic resonance (MR) and transmission electron microscopy (TEM). The TEM micrographs revealed magnetite nanoparticles attached externally to the cell wall. The MR data support the strong interaction among the nanoparticles supported by the cells. A remarkable shift in the resonance field was used as signature of particle attachment to the cell wall.

  2. Nuclear Magnetic Resonance Imaging. South Carolina Health Service Area 2

    SciTech Connect

    Not Available

    1984-12-01

    Contents include: Nuclear Magnetic Resonance Imaging (NMRI); (Clinical applications, Magnet types, Comparisons with other systems, Manpower, Manufacturers, Contraindications); Analysis of systems; (Availability, Accessibility, Cost, Quality, Continuity, Acceptability).

  3. Magnetic Resonance Force Microscopy Detected Long-Lived Spin Magnetization.

    PubMed

    Chen, Lei; Longenecker, Jonilyn G; Moore, Eric W; Marohn, John A

    2013-07-01

    Magnetic resonance force microscopy (MRFM), which combines magnetic resonance imaging with scanning probe microscopy together, is capable of performing ultra-sensitive detection of spin magnetization. In an attempt to observe dynamic nuclear polarization (DNP) in an MRFM experiment, which could possibly further improve its sensitivity towards a single proton spin, a film of perdeuterated polystyrene doped with a nitroxide electron-spin probe was prepared. A high-compliance cantilever with a 4 μm diameter magnetic tip was brought near the film at a temperature of 7.3 K and in a background magnetic field of ~0.6 T. The film was irradiated with 16.7 GHz microwaves while the resulting transient change in cantilever frequency was recorded in real time. In addition to observing the expected prompt change in cantilever frequency due to saturation of the nitroxide's electron-spin magnetization, we observed a persistent cantilever frequency change. Based on its magnitude, lifetime, and field dependence, we tentatively attribute the persistent signal to polarized deuteron magnetization created via transfer of magnetization from electron spins. Further measurements of the persistent signal's dependence on the cantilever amplitude and tip-sample separation are presented and explained by the cross-effect DNP mechanism in high magnetic field gradients.

  4. Interaction of magnetic resonators studied by the magnetic field enhancement

    SciTech Connect

    Hou, Yumin

    2013-12-15

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  5. Nuclear magnetic resonance properties of lunar samples.

    NASA Technical Reports Server (NTRS)

    Kline, D.; Weeks, R. A.

    1972-01-01

    Nuclear magnetic resonance spectra of Na-23, Al-27, and P-31 in fines samples 10084,60 and 14163,168 and in crystalline rock samples 12021,55 and 14321,166, have been recorded over a range of frequencies up to 20 MHz. A shift in the field at which maximum absorption occurs for all of the spectra relative to the field at which maximum absorption occurs for terrestrial analogues is attributed to a sample-dependent magnetic field at the Na, Al, and P sites opposing the laboratory field. The magnitude of these fields internal to the samples is sample dependent and varies from 5 to 10 G. These fields do not correlate with the iron content of the samples. However, the presence of single-domain particles of iron distributed throughout the plagioclase fraction that contains the principal fraction of Na and Al is inferred from electron magnetic resonance spectra shapes.

  6. Magnetic Earth Ionosphere Resonant Frequencies

    NASA Technical Reports Server (NTRS)

    Spaniol, Craig

    1994-01-01

    The Community College Division is pleased to report progress of NASA funded research at West Virginia State College. During this reporting period, the project research group has continued with activities to develop instrumentation capability designed to monitor resonant cavity frequencies in the atmospheric region between the Earth's surface and the ionosphere. In addition, the project's principal investigator, Dr. Craig Spaniol, and NASA technical officer, Dr. John Sutton, have written and published technical papers intended to expand the scientific and technical framework needed for project research. This research continues to provide an excellent example of government and education working together to provide significant research in the college environment. This cooperative effort has provided many students with technical project work which compliments their education.

  7. Prenatal magnetic resonance imaging as a useful adjunctive to ultrasound-enhanced diagnosis in case of a giant foetal tumour of the neck.

    PubMed

    Mittermayer, C; Brugger, P C; Lee, A; Horcher, E; Hayde, M; Bernaschek, G; Prayer, D

    2005-02-01

    Large cervical masses in the prenatal period are rare and can cause life threatening situations after birth. All available diagnostic techniques should therefore be used to determine the best mode of delivery in the case of such malformation. A large cervical mass was detected by ultrasound in a 41-year-old women, gravida 4, para 3, at 29 + 5 weeks of gestation. US imaging was most consistent with the diagnosis of a large cervical teratoma, but it was not possible to sufficiently evaluate the cervical anatomy of the oropharynx and trachea. An MRI scan demonstrated a distorted oropharynx and a trachea displaced to the right and posteriorly, but not detectable from the middle of the neck up to the larynx. Based on these facts, an EXIT procedure was planned and performed at 30 + 5 weeks of gestation. Foetal MRI provided valuable anatomical information for all specialists deciding on the indication and the pre-therapeutic planning of the EXIT procedure.

  8. Magnetic Resonance Elastography and Other Magnetic Resonance Imaging Techniques in Chronic Liver Disease: Current Status and Future Directions

    PubMed Central

    Tan, Cher Heng; Venkatesh, Sudhakar Kundapur

    2016-01-01

    Recent advances in the noninvasive imaging of chronic liver disease have led to improvements in diagnosis, particularly with magnetic resonance imaging (MRI). A comprehensive evaluation of the liver may be performed with the quantification of the degree of hepatic steatosis, liver iron concentration, and liver fibrosis. In addition, MRI of the liver may be used to identify complications of cirrhosis, including portal hypertension, ascites, and the development of hepatocellular carcinoma. In this review article, we discuss the state of the art techniques in liver MRI, namely, magnetic resonance elastography, hepatobiliary phase MRI, and liver fat and iron quantification MRI. The use of these advanced techniques in the management of chronic liver diseases, including non-alcoholic fatty liver disease, will be elaborated. PMID:27563019

  9. Magnetic Resonance Elastography and Other Magnetic Resonance Imaging Techniques in Chronic Liver Disease: Current Status and Future Directions.

    PubMed

    Tan, Cher Heng; Venkatesh, Sudhakar Kundapur

    2016-09-15

    Recent advances in the noninvasive imaging of chronic liver disease have led to improvements in diagnosis, particularly with magnetic resonance imaging (MRI). A comprehensive evaluation of the liver may be performed with the quantification of the degree of hepatic steatosis, liver iron concentration, and liver fibrosis. In addition, MRI of the liver may be used to identify complications of cirrhosis, including portal hypertension, ascites, and the development of hepatocellular carcinoma. In this review article, we discuss the state of the art techniques in liver MRI, namely, magnetic resonance elastography, hepatobiliary phase MRI, and liver fat and iron quantification MRI. The use of these advanced techniques in the management of chronic liver diseases, including nonalcoholic fatty liver disease, will be elaborated.

  10. Chronic thromboembolic pulmonary hypertension - assessment by magnetic resonance imaging.

    PubMed

    Kreitner, Karl-Friedrich; Kunz, R Peter; Ley, Sebastian; Oberholzer, Katja; Neeb, Daniel; Gast, Klaus K; Heussel, Claus-Peter; Eberle, Balthasar; Mayer, Eckhard; Kauczor, Hans-Ulrich; Düber, Christoph

    2007-01-01

    Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe disease that has been ignored for a long time. However, with the development of improved therapeutic modalities, cardiologists and thoracic surgeons have shown increasing interest in the diagnostic work-up of this entity. The diagnosis and management of chronic thromboembolic pulmonary hypertension require a multidisciplinary approach involving the specialties of pulmonary medicine, cardiology, radiology, anesthesiology and thoracic surgery. With this approach, pulmonary endarterectomy (PEA) can be performed with an acceptable mortality rate. This review article describes the developments in magnetic resonance (MR) imaging techniques for the diagnosis of chronic thromboembolic pulmonary hypertension. Techniques include contrast-enhanced MR angiography (ce-MRA), MR perfusion imaging, phase-contrast imaging of the great vessels, cine imaging of the heart and combined perfusion-ventilation MR imaging with hyperpolarized noble gases. It is anticipated that MR imaging will play a central role in the initial diagnosis and follow-up of patients with CTEPH.

  11. [Achilles tendon xanthoma imaging on ultrasound and magnetic resonance imaging].

    PubMed

    Fernandes, Eloy de Ávila; Santos, Eduardo Henrique Sena; Tucunduva, Tatiana Cardoso de Mello; Ferrari, Antonio J L; Fernandes, Artur da Rocha Correa

    2015-01-01

    The Achilles tendon xanthoma is a rare disease and has a high association with primary hyperlipidemia. An early diagnosis is essential to start treatment and change the disease course. Imaging exams can enhance diagnosis. This study reports the case of a 60-year-old man having painless nodules on his elbows and Achilles tendons without typical gout crisis, followed in the microcrystalline disease clinic of Unifesp for diagnostic workup. Laboratory tests obtained showed dyslipidemia. The ultrasound (US) showed a diffuse Achilles tendon thickening with hypoechoic areas. Magnetic resonance imaging (MRI) showed a diffuse tendon thickening with intermediate signal areas, and a reticulate pattern within. Imaging studies showed relevant aspects to diagnose a xanthoma, thus helping in the differential diagnosis.

  12. Gadolinium-enhanced magnetic resonance angiography in brain death

    NASA Astrophysics Data System (ADS)

    Luchtmann, M.; Beuing, O.; Skalej, M.; Kohl, J.; Serowy, S.; Bernarding, J.; Firsching, R.

    2014-01-01

    Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

  13. Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging.

    PubMed

    Assis, Reijâne Alves de; Kassab, Carolina; Seguro, Fernanda Salles; Costa, Fernando Ferreira; Silveira, Paulo Augusto Achucarro; Wood, John; Hamerschlak, Nelson

    2013-12-01

    To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions.

  14. Magnetic resonance of calcified tissues

    NASA Astrophysics Data System (ADS)

    Wehrli, Felix W.

    2013-04-01

    MRI of the human body is largely made possible by the favorable relaxation properties of protons of water and triacyl glycerides prevalent in soft tissues. Hard tissues - key among them bone - are generally less amenable to measurement with in vivo MR imaging techniques, not so much as a result of the lower proton density but rather due to the extremely short life-times of the proton signal in water bound to solid-like entities, typically collagen, or being trapped in micro-pores. Either mechanism can enhance T2 relaxation by up to three orders of magnitude relative to their soft-tissue counterparts. Detection of these protons requires solid-state techniques that have emerged in recent years and that promise to add a new dimension to the study of hard tissues. Alternative approaches to probe calcified tissues exploit their characteristic magnetic properties. Bone, teeth and extra-osseous calcium-containing biomaterials are unique in that they are more diamagnetic than all other tissues and thus yield information indirectly by virtue of the induced magnetic fields present in their vicinity. Progress has also been made in methods allowing very high-resolution structural imaging of trabecular and cortical bone relying on detection of the surrounding soft-tissues. This brief review, much of it drawn from work conducted in the author's laboratory, seeks to highlight opportunities with focus on early-stage developments for image-based assessment of structure, function, physiology and mechanics of calcified tissues in humans via liquid and solid-state approaches, including proton, deuteron and phosphorus NMR and MRI.

  15. Magnetic resonance of calcified tissues

    PubMed Central

    Wehrli, Felix W.

    2016-01-01

    MRI of the human body is largely made possible by the favorable relaxation properties of protons of water and triacyl glycerides prevalent in soft tissues. Hard tissues – key among them bone – are generally less amenable to measurement with in vivo MR imaging techniques, not so much as a result of the lower proton density but rather due to the extremely short life-times of the proton signal in water bound to solid-like entities, typically collagen, or being trapped in micro-pores. Either mechanism can enhance T2 relaxation by up to three orders of magnitude relative to their soft-tissue counterparts. Detection of these protons requires solid-state techniques that have emerged in recent years and that promise to add a new dimension to the study of hard tissues. Alternative approaches to probe calcified tissues exploit their characteristic magnetic properties. Bone, teeth and extra-osseous calcium-containing biomaterials are unique in that they are more diamagnetic than all other tissues and thus yield information indirectly by virtue of the induced magnetic fields present in their vicinity. Progress has also been made in methods allowing very high-resolution structural imaging of trabecular and cortical bone relying on detection of the surrounding soft-tissues. This brief review, much of it drawn from work conducted in the author’s laboratory, seeks to highlight opportunities with focus on early-stage developments for image-based assessment of structure, function, physiology and mechanics of calcified tissues in humans via liquid and solid-state approaches, including proton, deuteron and phosphorus NMR and MRI. PMID:23414678

  16. 21 CFR 892.1000 - Magnetic resonance diagnostic device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Magnetic resonance diagnostic device. 892.1000... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance...

  17. 21 CFR 892.1000 - Magnetic resonance diagnostic device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Magnetic resonance diagnostic device. 892.1000... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance...

  18. 21 CFR 892.1000 - Magnetic resonance diagnostic device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Magnetic resonance diagnostic device. 892.1000... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance...

  19. 21 CFR 892.1000 - Magnetic resonance diagnostic device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Magnetic resonance diagnostic device. 892.1000... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance...

  20. 21 CFR 892.1000 - Magnetic resonance diagnostic device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Magnetic resonance diagnostic device. 892.1000... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance...

  1. Prenatal ultrasound and magnetic resonance imaging depiction of a small sublingual ranula.

    PubMed

    Tamaru, Shunsuke; Kikuchi, Akihiko; Ono, Kyoko; Kita, Mariko; Horikoshi, Tsuguhiro; Takagi, Kimiyo

    2010-01-01

    Prenatal diagnosis of a congenital ranula has rarely been reported. We describe the case of a small ranula depicted on prenatal sonogram and magnetic resonance imaging, in which we could confirm the intact airway. Although the size of the ranula noted in our fetus was the smallest among the cases reported in the English literature, both of these imaging modalities clearly presented typical diagnostic features present on both ultrasound and magnetic resonance imaging.

  2. Submitral aneurysm and the new imaging modalities: Will magnetic resonance imaging be necessary?

    PubMed

    Morais, Humberto; Manuel, Valdano; Costa, João Carlos

    2016-10-01

    Submitral aneurysm is a rare cardiac malformation commonly reported in young adult African ancestry. Transthoracic echocardiogram is a gold standard test for diagnosis. Magnetic resonance imaging provides detailed anatomic and functional information of the heart. We present a case of a large bilobed submitral aneurysm in-witch the magnetic resonance imaging confirmed the same findings of the transthoracic echocardiography and in addiction also showed a parietal thrombus.

  3. Unusual Presentation of Hydatid Cyst in Breast with Magnetic Resonance Imaging Findings

    PubMed Central

    Koc, Ali; Vurdem, Umit Erkan; Karabiyik, Ozgur; Gumus, Ummugulsum Ozgul

    2017-01-01

    We report a case of 59-year-old woman with a painful left breast mass, compatible with types II-III hydatid cyst. Lesion was evaluated with mammography, ultrasound, computed tomography, and magnetic resonance imaging modalities. Magnetic resonance imaging had important diagnostic role with demonstrating characteristic features of the lesion and had capability of showing complications. Surgery also confirmed the diagnosis of a hydatid cyst. PMID:28167966

  4. [Magnetic resonance compatibility research for coronary mental stents].

    PubMed

    Wang, Ying; Liu, Li; Wang, Shuo; Shang, Ruyao; Wang, Chunren

    2015-01-01

    The objective of this article is to research magnetic resonance compatibility for coronary mental stents, and to evaluate the magnetic resonance compatibility based on laboratory testing results. Coronary stents magnetic resonance compatibility test includes magnetically induced displacement force test, magnetically induced torque test, radio frequency induced heating and evaluation of MR image. By magnetic displacement force and torque values, temperature, and image distortion values to determine metal coronary stent demagnetization effect. The methods can be applied to test magnetic resonance compatibility for coronary mental stents and evaluate its demagnetization effect.

  5. A hyperpolarized equilibrium for magnetic resonance.

    PubMed

    Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B; Mewis, Ryan E; Highton, Louise A R; Kenny, Stephen M; Green, Gary G R; Leibfritz, Dieter; Korvink, Jan G; Hennig, Jürgen; von Elverfeldt, Dominik

    2013-01-01

    Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all ¹H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10⁻³ Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.

  6. Magnetic resonance imaging with an optical atomicmagnetometer

    SciTech Connect

    Xu, Shoujun; Yashchuk, Valeriy V.; Donaldson, Marcus H.; Rochester, Simon M.; Budker, Dmitry; Pines, Alexander

    2006-05-09

    Magnetic resonance imaging (MRI) is a noninvasive andversatile methodology that has been applied in many disciplines1,2. Thedetection sensitivity of conventional Faraday detection of MRI depends onthe strength of the static magnetic field and the sample "fillingfactor." Under circumstances where only low magnetic fields can be used,and for samples with low spin density or filling factor, the conventionaldetection sensitivity is compromised. Alternative detection methods withhigh sensitivity in low magnetic fields are thus required. Here we showthe first use of a laser-based atomic magnetometer for MRI detection inlow fields. Our technique also employs remote detection which physicallyseparates the encoding and detection steps3-5, to improve the fillingfactor of the sample. Potentially inexpensive and using a compactapparatus, our technique provides a novel alternative for MRI detectionwith substantially enhanced sensitivity and time resolution whileavoiding the need for cryogenics.

  7. [Is magnetic resonance imaging absolutely necessary for musculotendinous disease?].

    PubMed

    García González, Pedro; Meana Morís, Ana R

    2016-01-01

    Disorders of the musculoskeletal system are very prevalent in our society, especially those involving muscles and tendons, above all related to sports and work. These conditions are normally diagnosed and treated according to their clinical symptoms and signs, but a precise diagnosis is often necessary. The most widely used techniques for diagnosing these conditions are ultrasonography and magnetic resonance imaging. In this article, we propose ultrasonography as the technique of choice for diagnosing the most prevalent musculotendinous diseases, because it is accurate, versatile, dynamic, and effective.

  8. Resonantly Detecting Axion-Mediated Forces with Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Arvanitaki, Asimina; Geraci, Andrew A.

    2014-10-01

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 109 and 1012 GeV or axion masses between 10-6 and 10-3 eV, independent of the cosmic axion abundance.

  9. Magnetic resonance imaging of the elbow.

    PubMed

    Stevens, Kathryn J

    2010-05-01

    Elbow pain is frequently encountered in clinical practice and can result in significant morbidity, particularly in athletes. Magnetic resonance imaging (MRI) is an excellent diagnostic imaging tool for the evaluation of soft tissue and osteochondral pathology around the elbow. Recent advances in magnetic field strength and coil design have lead to improved spatial resolution and superior soft tissue contrast, making it ideal for visualization of complex joint anatomy. This article describes the normal imaging appearances of anatomy around the elbow and reviews commonly occurring ligamentous, myotendinous, neural, and bursal pathology around the elbow.

  10. Antiferromagnetic resonance excitation by terahertz magnetic field resonantly enhanced with split ring resonator

    SciTech Connect

    Mukai, Y.; Hirori, H.; Yamamoto, T.; Kageyama, H.; Tanaka, K.

    2014-07-14

    Excitation of antiferromagnetic resonance (AFMR) in a HoFeO{sub 3} crystal combined with a split ring resonator (SRR) is studied using terahertz (THz) electromagnetic pulses. The magnetic field in the vicinity of the SRR is induced by the incident THz electric field component and excites spin oscillations that correspond to the AFMR, which are directly probed by the Faraday rotation of the polarization of a near-infrared probe pulse. The good agreement of the temperature-dependent magnetization dynamics with the calculation using the two-lattice Landau-Lifshitz-Gilbert equation confirms that the AFMR is excited by the THz magnetic field, which is enhanced at the SRR resonance frequency by a factor of 20 compared to the incident magnetic field.

  11. Proton magnetic resonance spectroscopy in multiple sclerosis

    SciTech Connect

    Wolinsky, J.S.; Narayana, P.A.; Fenstermacher, M.J. )

    1990-11-01

    Regional in vivo proton magnetic resonance spectroscopy provides quantitative data on selected chemical constituents of brain. We imaged 16 volunteers with clinically definite multiple sclerosis on a 1.5 tesla magnetic resonance scanner to define plaque-containing volumes of interest, and obtained localized water-suppressed proton spectra using a stimulated echo sequence. Twenty-five of 40 plaque-containing regions provided spectra of adequate quality. Of these, 8 spectra from 6 subjects were consistent with the presence of cholesterol or fatty acids; the remainder were similar to those obtained from white matter of normal volunteers. This early experience with regional proton spectroscopy suggests that individual plaques are distinct. These differences likely reflect dynamic stages of the evolution of the demyelinative process not previously accessible to in vivo investigation.

  12. Combined Confocal and Magnetic Resonance Microscopy

    SciTech Connect

    Wind, Robert A.; Majors, Paul D.; Minard, Kevin R.; Ackerman, Eric J.; Daly, Don S.; Holtom, Gary R.; Thrall, Brian D.; Weber, Thomas J.

    2002-05-12

    Confocal and magnetic resonance microscopy are both used to study live cells in a minimally invasive way. Both techniques provide complementary information. Therefore, by examining cells simultaneously with both methodologies, more detailed information is obtained than is possible with each of the microscopes individually. In this paper two configurations of a combined confocal and magnetic resonance microscope described. In both cases the sample compartment is part of a temperature regulated perfusion system. The first configuration is capable of studying large single cells or three-dimensional cell agglomerates, whereas with the second configuration monolayers of mammalian cells can be investigated . Combined images are shown of Xenopus laevis frog oocytes, model JB6 tumor spheroids, and a single layer of Chinese hamster ovary cells. Finally, potential applications of the combined microscope are discussed.

  13. Magnetic resonances in nano-scale metamaterials

    NASA Astrophysics Data System (ADS)

    Hao, Zhao; Liddle, Alex; Martin, Michael

    2006-03-01

    We have designed, fabricated, and optically measured several different kinds of nano-scale metamaterials. We make use e-beam nano-lithography technology at LBNL's Center for X-Ray Optics for fabricating these structures on extremely thin SiN substrates so that they are close to free-standing. Optical properties were measured as a function of incidence angle and polarization. We directly observe a strong magnetic resonance consistent with a negative magnetic permeability in our samples at mid- and near-IR optical frequencies. We will discuss the results in comparison with detailed simulations, and will discuss the electric dipole or quadrupole resonances observed in the samples. Finally, we will report on our progress towards constructing a fully negative index of refraction meta-material.

  14. Magnetic Resonance Imaging Guided Vacuum Assisted and Core Needle Biopsies

    PubMed Central

    Kılıç, Fahrettin; Eren, Abdulkadir; Tunç, Necmettin; Velidedeoğlu, Mehmet; Bakan, Selim; Aydoğan, Fatih; Çelik, Varol; Gazioğlu, Ertuğrul; Yılmaz, Mehmet Halit

    2016-01-01

    Objective The purpose of this study to present the results of Magnetic resonance imaging (MRI) guided cutting needle biopsy procedures of suspicious breast lesions that can be solely detected on Magnetic resonance (MR) examination. Materials and Methods The study included 48 patients with 48 lesions which were solely be observed in breast MRI, indistinguishable in ultrasonography and mammography, for MR guided vacuum-assisted cutting needle biopsy and 42 patients with 42 lesions for MR guided cutting needle biopsy for the lesions of the same nature. MR imaging was performed using a 1.5-Tesla MRI device. Acquired MR images were determined and biopsy protocol was performed using computer-aided diagnosis system on the workstation. Vacuum biopsies were performed using 10 G or 12 G automatic biopsy systems, cutting needle biopsy procedures were performed using fully automated 12 G biopsy needle. Results All biopsy procedures were finalized successfully without major complications. The lesions were 54 mass (60%), 28 were non-mass contrast enhancement (31%) and 8 were foci (9%) in the MR examination. Histopathological evaluation revealed 18 malignant (invasive, in-situ ductal carcinoma and lobular carcinoma), 66 benign (apocrine metaplasia, fibrosis, fibroadenomatoid lesion, sclerosing adenosis, fibrocystic disease and mild-to-severe epithelial proliferation) and 6 high-risk (atypical ductal hyperplasia, intraductal papilloma, radial scar) lesions. Conclusion Magnetic resonance guided vacuum and cutting needle biopsy methods are successful methods fort he evaluation of solely MRI detected suspicious breast lesions. There are several advantages relative to each other in both methods.

  15. Tissue discrimination in magnetic resonance imaging of the rotator cuff

    NASA Astrophysics Data System (ADS)

    Meschino, G. J.; Comas, D. S.; González, M. A.; Capiel, C.; Ballarin, V. L.

    2016-04-01

    Evaluation and diagnosis of diseases of the muscles within the rotator cuff can be done using different modalities, being the Magnetic Resonance the method more widely used. There are criteria to evaluate the degree of fat infiltration and muscle atrophy, but these have low accuracy and show great variability inter and intra observer. In this paper, an analysis of the texture features of the rotator cuff muscles is performed to classify them and other tissues. A general supervised classification approach was used, combining forward-search as feature selection method with kNN as classification rule. Sections of Magnetic Resonance Images of the tissues of interest were selected by specialist doctors and they were considered as Gold Standard. Accuracies obtained were of 93% for T1-weighted images and 92% for T2-weighted images. As an immediate future work, the combination of both sequences of images will be considered, expecting to improve the results, as well as the use of other sequences of Magnetic Resonance Images. This work represents an initial point for the classification and quantification of fat infiltration and muscle atrophy degree. From this initial point, it is expected to make an accurate and objective system which will result in benefits for future research and for patients’ health.

  16. Magnetic resonance enterography findings of chronic radiation enteritis

    PubMed Central

    Algin, Oktay; Turkbey, Baris; Ozmen, Evrim

    2011-01-01

    Abstract The diagnosis of chronic radiation enteritis (CRE) is considerably challenging both for clinicians and radiologists. The aim of this study was to evaluate the role of magnetic resonance enterography (MRE) in the diagnosis of CRE. To the best of our knowledge, there are no reports on the role of MRE in the diagnosis of CRE specifically. In this report, we present MRE findings of 4 patients with CRE. The most important factors in CRE diagnosis are the clinical findings and medical history, but focal abnormal bowel loop in the region of a known radiation field is the most important information. This abnormal loop is generally located in the distal ileum as present in our patients. Other associated findings helpful for the diagnosis are small bowel thickening, contrast material enhancement in a long segment, mesenteric stranding and luminal narrowing. MRE can be sufficient and useful in the diagnosis of CRE and for treatment planning, especially in patients with significant comorbidities who have had radiotherapy in the past. Adding MRE into the diagnostic algorithm can be helpful in post-radiotherapy patients with acute/subacute gastrointestinal symptoms. PMID:22138564

  17. Neurosurgical uses for intraprocedural magnetic resonance imaging.

    PubMed

    Mutchnick, Ian S; Moriarty, Thomas M

    2005-10-01

    Neurosurgical procedures demand precision, and efforts to create accurate neurosurgical navigation have been central to the profession through its history. Magnetic resonance image (MRI)-guided navigation offers the possibility of real-time, image-based stereotactic information for the neurosurgeon, which makes possible a number of diagnostic and therapeutic procedures. This article will review both current options for intraoperative MRI operative suite arrangements and the current therapeutic/diagnostic uses of intraoperative MRI.

  18. Fluctuating magnetic field induced resonant activation

    SciTech Connect

    Mondal, Shrabani; Das, Sudip; Baura, Alendu; Bag, Bidhan Chandra

    2014-12-14

    In this paper, we have studied the properties of a Brownian particle at stationary state in the presence of a fluctuating magnetic field. Time dependence of the field makes the system thermodynamically open. As a signature of that the steady state distribution function becomes function of damping strength, intensity of fluctuations and constant parts of the applied magnetic field. It also depends on the correlation time of the fluctuating magnetic field. Our another observation is that the random magnetic field can induce the resonant activation phenomenon. Here correlation time is increased under the fixed variance of the fluctuating field. But if the correlation time (τ) increases under the fixed field strength then the mean first passage time rapidly grows at low τ and it almost converges at other limit. This is sharp contrast to the usual colored noise driven open system case where the mean first passage time diverges exponentially. We have also observed that a giant enhancement of barrier crossing rate occurs particularly at large strength of constant parts of the applied magnetic field even for very weak fluctuating magnetic field. Finally, break down of the Arrhenius result and disappearance of the Kramers’ turn over phenomenon may occur in the presence of a fluctuating magnetic field.

  19. Magnetic resonance venography and liver transplant complications.

    PubMed

    Strovski, Evgeny; Liu, Dave; Scudamore, Charles; Ho, Stephen; Yoshida, Eric; Klass, Darren

    2013-09-28

    Hepatic vein stenosis is a rare but serious complication following liver transplantation. Multiple modalities can be utilized to image the hepatic vasculature. Magnetic resonance venography (MRV) provides certain advantages over ultrasound, computed tomography angiography and digital subtraction venography. MRV utilizes the same imaging principles of magnetic resonance angiography in order to image the venous system. Blood pool contrast agents, specifically gadofosveset trisodium, allow for steady state imaging up to 1 h following injection, with improved visualisation of vital venous structures by utilising delayed steady state imaging. Additionally, the inherent physics properties of magnetic resonance imaging also provide excellent soft tissue detail and thus help define the extent of complications that often plague the post-liver transplant patient. This case report describes the use of gadofosveset trisodium in a patient with hepatic venous stenosis following liver transplantation. Initial venography failed to outline the stenoses and thus MRV using a blood pool contrast agent was utilised in order to delineate the anatomy and plan a therapeutic endovascular procedure.

  20. Magnetic resonance acoustic radiation force imaging.

    PubMed

    McDannold, Nathan; Maier, Stephan E

    2008-08-01

    Acoustic radiation force impulse imaging is an elastography method developed for ultrasound imaging that maps displacements produced by focused ultrasound pulses systematically applied to different locations. The resulting images are "stiffness weighted" and yield information about local mechanical tissue properties. Here, the feasibility of magnetic resonance acoustic radiation force imaging (MR-ARFI) was tested. Quasistatic MR elastography was used to measure focal displacements using a one-dimensional MRI pulse sequence. A 1.63 or 1.5 MHz transducer supplied ultrasound pulses which were triggered by the magnetic resonance imaging hardware to occur before a displacement-encoding gradient. Displacements in and around the focus were mapped in a tissue-mimicking phantom and in an ex vivo bovine kidney. They were readily observed and increased linearly with acoustic power in the phantom (R2=0.99). At higher acoustic power levels, the displacement substantially increased and was associated with irreversible changes in the phantom. At these levels, transverse displacement components could also be detected. Displacements in the kidney were also observed and increased after thermal ablation. While the measurements need validation, the authors have demonstrated the feasibility of detecting small displacements induced by low-power ultrasound pulses using an efficient magnetic resonance imaging pulse sequence that is compatible with tracking of a dynamically steered ultrasound focal spot, and that the displacement increases with acoustic power. MR-ARFI has potential for elastography or to guide ultrasound therapies that use low-power pulsed ultrasound exposures, such as drug delivery.

  1. Use of magnetic resonance cholangiopancreatography to diagnose neonatal congenital choledochal cyst.

    PubMed

    Lin, Wei-Jen; Yu, Chih-Yung; Diau, Guan-Yeu; Chen, Chun-Jung; Lee, Chuen-Ming

    2005-06-01

    Antenatal identification of choledochal cysts has become increasingly common with advances in prenatal ultrasonography. However, the antenatal diagnosis needs to be confirmed postnatally and a preoperative radiologic evaluation of the cyst prior to complete resection is required. There have been few reports of the application of magnetic resonance cholangiopancreatography in neonates, or in neonates with large choledochal cysts. We describe a neonate with a progressively growing giant choledochal cyst, which was initially detected at 28 weeks' gestation. After delivery, the baby did not feed well and suffered from jaundice and frequent postprandial bilious vomiting. At the age of 11 days, magnetic resonance cholangiopancreatography was used to confirm the prenatal diagnosis and provide a thorough preoperative evaluation. He underwent early resection of the cyst at 15 days of age and recovered uneventfully. Magnetic resonance cholangiopancreatography is an alternative diagnostic method for confirming the antenatal diagnosis of large choledochal cysts in neonates. It may also provide useful diagnostic information for preoperative evaluation.

  2. Fault diagnosis for magnetic bearing systems

    NASA Astrophysics Data System (ADS)

    Tsai, Nan-Chyuan; King, Yueh-Hsun; Lee, Rong-Mao

    2009-05-01

    A full fault diagnosis for active magnetic bearing (AMB) and rotor systems to monitor the closed-loop operation and analyze fault patterns on-line in case any malfunction occurs is proposed in this paper. Most traditional approaches for fault diagnosis are based on actuator or sensor diagnosis individually and can solely detect a single fault at a time. This research combines two diagnosis methodologies by using both state estimators and parameter estimators to detect, identify and analyze actuators and sensors faults in AMB/rotor systems. The proposed fault diagnosis algorithm not only enhances the diagnosis accuracy, but also illustrates the capability to detect multiple sensors faults which occur concurrently. The efficacy of the presented algorithm has been verified by computer simulations and intensive experiments. The test rig for experiments is equipped with AMB, interface module (dSPACE DS1104), data acquisition unit MATLAB/Simulink simulation environment. At last, the fault patterns, such as bias, multiplicative loop gain variation and noise addition, can be identified by the algorithm presented in this work. In other words, the proposed diagnosis algorithm is able to detect faults at the first moment, find which sensors or actuators under failure and identify which fault pattern the found faults belong to.

  3. Artifacts in magnetic resonance imaging from metals

    NASA Astrophysics Data System (ADS)

    Bennett, L. H.; Wang, P. S.; Donahue, M. J.

    1996-04-01

    Metallic biomedical implants, such as aneurysm clips, endoprostheses, and internal orthopedic devices give rise to artifacts in the magnetic resonance image (MRI) of patients. Such artifacts impair the information contained in the image in precisely the region of most interest, namely near the metallic device. Ferromagnetic materials are contraindicated because of the hazards associated with their movement during the MRI procedure. In less-magnetic metals, it has been suggested that the extent of the artifact is related to the magnetic susceptibility of the metal, but no systematic data appear to be available. When the susceptibility is sufficiently small, an additional artifact due to electrical conductivity is observed. We present an initial systematic study of MRI artifacts produced by two low susceptibility metals, titanium (relative permeability μr≊1.0002) and copper (μr≊0.99998), including experimental, theoretical, and computer simulation results.

  4. Magnetic resonance imaging of avascular necrosis of the lunate.

    PubMed

    Jackson, M D; Barry, D T; Geiringer, S R

    1990-06-01

    Avascular necrosis (AVN) of carpal bones, particularly the lunate, is often an elusive cause of wrist pain. Physical examination can be indistinguishable from that of a simple wrist sprain, and standard radiographic evaluations are frequently normal. Early diagnosis is critical, since late treatment is often simple observation of the natural history of the disease, which includes progressive collapse of the lunate and derangement of the carpal architecture. Magnetic resonance imaging (MRI) produces images of high contrast, demarcating necrotic from normal bone. We present a case of lunate AVN ("Kienböck's disease") to illustrate the ability of MRI to identify necrotic bone in the wrist. We suggest that MRI is useful in diagnosing AVN in the wrist and that it may allow an earlier diagnosis of lunate AVN than is possible with standard radiographs.

  5. Utility of Magnetic Resonance Imaging in Cardiac Venous Anatomic Variants

    SciTech Connect

    Eckart, Robert E. Leitch, W. Shad; Shry, Eric A.; Krasuski, Richard A.; Lane, Michael J.; Leclerc, Kenneth M.

    2003-06-15

    The incidence of persistent left superior venacava (PLSVC) is approximately 0.5% in the general population; however,the coexistent absence of the right SVC has a reported incidence in tertiary centers of 0.1%. The vast majority of reports are limited to pediatric cardiology. Likewise, sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1-3.5% of all congenital heart defects. We present a 71-year-old patient undergoing preoperative evaluation for incidental finding of aortic root aneurysm,and found to have all three in coexistence. Suggestive findings were demonstrated on cardiac catheterization and definitive diagnosis was made by magnetic resonance imaging. The use of MRI for the diagnosis of asymptomatic adult congenital heart disease will be reviewed.

  6. Magnetic Resonance Imaging: Principles and Techniques: Lessons for Clinicians

    PubMed Central

    Grover, Vijay P.B.; Tognarelli, Joshua M.; Crossey, Mary M.E.; Cox, I. Jane; Taylor-Robinson, Simon D.; McPhail, Mark J.W.

    2015-01-01

    The development of magnetic resonance imaging (MRI) for use in medical investigation has provided a huge forward leap in the field of diagnosis, particularly with avoidance of exposure to potentially dangerous ionizing radiation. With decreasing costs and better availability, the use of MRI is becoming ever more pervasive throughout clinical practice. Understanding the principles underlying this imaging modality and its multiple applications can be used to appreciate the benefits and limitations of its use, further informing clinical decision-making. In this article, the principles of MRI are reviewed, with further discussion of specific clinical applications such as parallel, diffusion-weighted, and magnetization transfer imaging. MR spectroscopy is also considered, with an overview of key metabolites and how they may be interpreted. Finally, a brief view on how the use of MRI will change over the coming years is presented. PMID:26628842

  7. Integrated imaging of neuromagnetic reconstructions and morphological magnetic resonance data.

    PubMed

    Kullmann, W H; Fuchs, M

    1991-01-01

    New neuromagnetic imaging methods provide spatial information about the functional electrical properties of complex current distributions in the human brain. For practical use in medical diagnosis a combination of the abstract neuromagnetic imaging results with magnetic resonance (MR) or computed tomography (CT) images of the morphology is required. The biomagnetic images can be overlayed onto three-dimensional morphological images with spatially arbitrary selectable slices, calculated from conventional 2D data. For the current reconstruction the 3D images furthermore provide a priori information about the conductor geometry. A combination of current source density calculations and linear estimation methods for handling the inverse magnetic problem allows quick imaging of impressed current source density in arbitrary volume conductors.

  8. [Stress fractures in athletes. role of magnetic resonance imaging in predicting injury morbidity].

    PubMed

    Maquirriain, Javier; Ghisi, Juan Pablo

    2007-01-01

    Magnetic resonance imaging is a useful tool for stress fractures (SF) diagnosis, allowing the estimation of injury severity. The aim of this study was to determine the relation between the severity of SF in athletes determined by magnetic resonance imaging and the morbidity estimated as the time to return to sport. Thirty-four cases of stress fractures, (29 athletes; 12 female, 17 male; age 26.3 +/- 12.5), were studied by radiographs and magnetic resonance imaging. Injuries were classified according to Arendt's scale and they were analyzed according to site, activity level, delay in diagnosis and time needed to return to sports. The tibia was the most affected bone (n=12; 35.2%), followed by the tarsal navicular (n=5; 14.7%), and the metatarsals (n=4; 11.7%). Injury severity according to magnetic resonance imaging appearance was: grade 1=14.7%; grade 2=14.7%; grade 3=38.2%; grade 4=32.4%. The main finding was the positive significant correlation between injury severity and recovery time (r=0.66, p=0.0002). In conclusion, significant correlation exists between stress fracture injury severity determined by magnetic resonance image and recovery time in athletes. The use of a systematic graded magnetic resonance image evaluation may assist the physician to define clinical management, supervise the rehabilitation program and estimate the return to sport activity.

  9. Magnetic resonance force detection using a membrane resonator

    NASA Astrophysics Data System (ADS)

    Scozzaro, Nicolas; Ruchotzke, William; Belding, Amanda; Cardellino, Jeremy; Blomberg, Erick; McCullian, Brendan; Bhallamudi, Vidya; Pelekhov, Denis; Hammel, P. Chris

    Silicon nitride (Si3N4) membranes are commercially-available, versatile structures that have a variety of applications. Although most commonly used as the support structure for transmission electron microscopy (TEM) studies, membranes are also ultrasensitive high-frequency mechanical oscillators. The sensitivity stems from the high quality factor Q 106 , which has led to applications in sensitive quantum optomechanical experiments. The high sensitivity also opens the door to ultrasensitive force detection applications. We report force detection of electron spin magnetic resonance at 300 K using a Si3N4 membrane with a force sensitivity of 4 fN/√{ Hz}, and a potential low temperature sensitivity of 25 aN/√{ Hz}. Given membranes' sensitivity, robust construction, large surface area and low cost, SiN membranes can potentially serve as the central component of a compact room-temperature ESR and NMR instrument that has superior spatial resolution to conventional NMR.

  10. Multimodal imaging of human cerebellum - merging X-ray phase microtomography, magnetic resonance microscopy and histology

    NASA Astrophysics Data System (ADS)

    Schulz, Georg; Waschkies, Conny; Pfeiffer, Franz; Zanette, Irene; Weitkamp, Timm; David, Christian; Müller, Bert

    2012-11-01

    Imaging modalities including magnetic resonance imaging and X-ray computed tomography are established methods in daily clinical diagnosis of human brain. Clinical equipment does not provide sufficient spatial resolution to obtain morphological information on the cellular level, essential for applying minimally or non-invasive surgical interventions. Therefore, generic data with lateral sub-micrometer resolution have been generated from histological slices post mortem. Sub-cellular spatial resolution, lost in the third dimension as a result of sectioning, is obtained using magnetic resonance microscopy and micro computed tomography. We demonstrate that for human cerebellum grating-based X-ray phase tomography shows complementary contrast to magnetic resonance microscopy and histology. In this study, the contrast-to-noise values of magnetic resonance microscopy and phase tomography were comparable whereas the spatial resolution in phase tomography is an order of magnitude better. The registered data with their complementary information permit the distinct segmentation of tissues within the human cerebellum.

  11. Basic principles of magnetic resonance imaging.

    PubMed

    McGowan, Joseph C

    2008-11-01

    Magnetic resonance (MR) imaging has become the dominant clinical imaging modality with widespread, primarily noninvasive, applicability throughout the body and across many disease processes. The flexibility of MR imaging enables the development of purpose-built optimized applications. Concurrent developments in digital image processing, microprocessor power, storage, and computer-aided design have spurred and enabled further growth in capability. Although MR imaging may be viewed as "mature" in some respects, the field is rich with new proposals and applications that hold great promise for future research health care uses. This article delineates the basic principles of MR imaging and illuminates specific applications.

  12. Review: Magnetic resonance imaging techniques in ophthalmology

    PubMed Central

    Fagan, Andrew J.

    2012-01-01

    Imaging the eye with magnetic resonance imaging (MRI) has proved difficult due to the eye’s propensity to move involuntarily over typical imaging timescales, obscuring the fine structure in the eye due to the resulting motion artifacts. However, advances in MRI technology help to mitigate such drawbacks, enabling the acquisition of high spatiotemporal resolution images with a variety of contrast mechanisms. This review aims to classify the MRI techniques used to date in clinical and preclinical ophthalmologic studies, describing the qualitative and quantitative information that may be extracted and how this may inform on ocular pathophysiology. PMID:23112569

  13. Magnetic Resonance Imaging of the Retina

    PubMed Central

    Duong, Timothy Q.; Muir, Eric R.

    2010-01-01

    This paper reviews recent developments in high-resolution magnetic resonance imaging (MRI) and its application to image anatomy, physiology, and function in the retina of animals. It describes technical issues and solutions in performing retinal MRI, anatomical MRI, blood oxygenation level-dependent functional MRI (fMRI), and blood-flow MRI both of normal retinas and of retinal degeneration. MRI offers unique advantages over existing retinal imaging techniques, including the ability to image multiple layers without depth limitation and to provide multiple clinically relevant data in a single setting. Retinal MRI has the potential to complement existing retinal imaging techniques. PMID:19763752

  14. Magnetic Resonance Imaging in Epidemic Adenoviral Keratoconjunctivitis

    PubMed Central

    Horton, Jonathan C.; Miller, Steven

    2015-01-01

    Most clinicians would agree that there is no reason to obtain a magnetic resonance (MR) scan to evaluate a patient with viral conjunctivitis. We scheduled a patient for an annual MR scan to monitor his optic nerve meningiomas. By coincidence, he had florid viral conjunctivitis the day the scan was performed. It showed severe eyelid edema, contrast enhancement of the anterior orbit, enlargement of the lacrimal gland, and obstruction of the nasolacrimal duct. Adenovirus produces deep orbital inflammation, in addition to infection of the conjunctival surface. PMID:26022084

  15. Magnetic resonance imaging of the nasopharynx

    SciTech Connect

    Dillon, W.P.; Mills, C.M.; Kjos, B.; DeGroot, J.; Brant-Zawadzki, M.

    1984-09-01

    Thirty subjects with normal nasopharyngeal anatomy and 12 patients with a variety of abnormalities were examined with computed tomography (CT) and magnetic resonance imaging (MR), using a prototype 0.35-T superconducting system. MR was superior to CT for display of both superficial and deep nasopharyngeal soft tissues in all 30 normal subjects and 10 of the 12 abnormal patients. MR was also superior to CT in distinguishing tumor from soft tissues and more sensitive to carotid sheath adenopathy. Bones, calcification, and subtle abnormalities at the base of the skull were shown better by CT. The specificity of MR and its ability to differentiate nodal metastases from reactive lymphadenopathy require further evaluation.

  16. Optically pumped nuclear magnetic resonance of semiconductors.

    PubMed

    Hayes, Sophia E; Mui, Stacy; Ramaswamy, Kannan

    2008-02-07

    Optically pumped NMR (OPNMR) of direct gap and indirect gap semiconductors has been an area of active research interest, motivated by both basic science and technological perspectives. Proposals to enhance and to spatially localize nuclear polarization have stimulated interest in this area. Recent progress in OPNMR has focused on exploring the experimental parameter space in order to elucidate details of the underlying photophysics of optical pumping phenomena. The focus of this review is on recent studies of bulk samples of GaAs and InP, namely, the photon energy dependence, the magnetic field dependence, and the phase dependence of OPNMR resonances. Models for the development of nuclear polarization are discussed.

  17. Creating a magnetic resonance imaging ontology

    PubMed Central

    Lasbleiz, Jérémy; Saint-Jalmes, Hervé; Duvauferrier, Régis; Burgun, Anita

    2011-01-01

    The goal of this work is to build an ontology of Magnetic Resonance Imaging. The MRI domain has been analysed regarding MRI simulators and the DICOM standard. Tow MRI simulators have been analysed: JEMRIS, which is developed in XML and C++, has a hierarchical organisation and SIMRI, which is developed in C, has a good representation of MRI physical processes. To build the ontology we have used Protégé 4, owl2 that allows quantitative representations. The ontology has been validated by a reasoner (Fact++) and by a good representation of DICOM headers and of MRI processes. The MRI ontology would improved MRI simulators and eased semantic interoperability. PMID:21893854

  18. Developments in boron magnetic resonance imaging (MRI)

    SciTech Connect

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  19. Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Seedhouse, Steven J.; Hoffmann, Markus M.

    2008-01-01

    A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the…

  20. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.

    1986-01-01

    During the past year the Woodlands Baylor Magnetic Resonance Imaging (MRI) facility became fully operational. A detailed description of this facility is given. One significant instrument addition this year was the 100 MHz, 40cm bore superconducting imaging spectrometer. This instrument gives researchers the capability to acquire high energy phosphate spectra. This will be used to investigate ATP, phosphocreatinine and inorganic phosphate changes in normal and atrophied muscle before, during and after exercise. An exercise device for use within the bore of the imaging magnet is under design/construction. The results of a study of T sub 1 and T sub 2 changes in atrophied muscle in animals and human subjects are given. The imaging and analysis of the lower leg of 15 research subjects before and after 5 weeks of complete bedrest was completed. A compilation of these results are attached.

  1. Plasmon coupling of magnetic resonances in an asymmetric gold semishell

    NASA Astrophysics Data System (ADS)

    Ye, Jian; Kong, Yan; Liu, Cheng

    2016-05-01

    The generation of magnetic dipole resonances in metallic nanostructures is of great importance for constructing near-zero or even negative refractive index metamaterials. Commonly, planar two-dimensional (2D) split-ring resonators or relevant structures are basic elements of metamaterials. In this work, we introduce a three-dimensional (3D) asymmetric Au semishell composed of two nanocups with a face-to-face geometry and demonstrate two distinct magnetic resonances spontaneously in the visible-near infrared optical wavelength regime. These two magnetic resonances are from constructive and destructive hybridization of magnetic dipoles of individual nanocups in the asymmetric semishell. In contrast, complete cancellation of magnetic dipoles in the symmetric semishell leads to only a pronounced electric mode with near-zero magnetic dipole moment. These 3D asymmetric resonators provide new ways for engineering hybrid resonant modes and ultra-high near-field enhancement for the design of 3D metamaterials.

  2. Science Drivers and Technical Challenges for Advanced Magnetic Resonance

    SciTech Connect

    Mueller, Karl T.; Pruski, Marek; Washton, Nancy M.; Lipton, Andrew S.

    2013-03-07

    This report recaps the "Science Drivers and Technical Challenges for Advanced Magnetic Resonance" workshop, held in late 2011. This exploratory workshop's goal was to discuss and address challenges for the next generation of magnetic resonance experimentation. During the workshop, participants from throughout the world outlined the science drivers and instrumentation demands for high-field dynamic nuclear polarization (DNP) and associated magnetic resonance techniques, discussed barriers to their advancement, and deliberated the path forward for significant and impactful advances in the field.

  3. General review of magnetic resonance elastography

    PubMed Central

    Low, Gavin; Kruse, Scott A; Lomas, David J

    2016-01-01

    Magnetic resonance elastography (MRE) is an innovative imaging technique for the non-invasive quantification of the biomechanical properties of soft tissues via the direct visualization of propagating shear waves in vivo using a modified phase-contrast magnetic resonance imaging (MRI) sequence. Fundamentally, MRE employs the same physical property that physicians utilize when performing manual palpation - that healthy and diseased tissues can be differentiated on the basis of widely differing mechanical stiffness. By performing “virtual palpation”, MRE is able to provide information that is beyond the capabilities of conventional morphologic imaging modalities. In an era of increasing adoption of multi-parametric imaging approaches for solving complex problems, MRE can be seamlessly incorporated into a standard MRI examination to provide a rapid, reliable and comprehensive imaging evaluation at a single patient appointment. Originally described by the Mayo Clinic in 1995, the technique represents the most accurate non-invasive method for the detection and staging of liver fibrosis and is currently performed in more than 100 centers worldwide. In this general review, the mechanical properties of soft tissues, principles of MRE, clinical applications of MRE in the liver and beyond, and limitations and future directions of this discipline -are discussed. Selected diagrams and images are provided for illustration. PMID:26834944

  4. Magnetic resonance imaging. Application to family practice.

    PubMed Central

    Goh, R. H.; Somers, S.; Jurriaans, E.; Yu, J.

    1999-01-01

    OBJECTIVE: To review indications, contraindications, and risks of using magnetic resonance imaging (MRI) in order to help primary care physicians refer patients appropriately for MRI, screen for contraindications to using MRI, and educate patients about MRI. QUALITY OF EVIDENCE: Recommendations are based on classic textbooks, the policies of our MRI group, and a literature search using MEDLINE with the MeSH headings magnetic resonance imaging, brain, musculoskeletal, and spine. The search was limited to human, English-language, and review articles. Evidence in favour of using MRI for imaging the head, spine, and joints is well established. For cardiac, abdominal, and pelvic conditions, MRI has been shown useful for certain indications, usually to complement other modalities. MAIN MESSAGE: For demonstrating soft tissue conditions, MRI is better than computed tomography (CT), but CT shows bone and acute bleeding better. Therefore, patients with trauma or suspected intracranial bleeding should have CT. Tumours, congenital abnormalities, vascular structures, and the cervical or thoracic spine show better on MRI. Either modality can be used for lower back pain. Cardiac, abdominal, and pelvic abnormalities should be imaged with ultrasound or CT before MRI. Contraindications for MRI are mainly metallic implants or shrapnel, severe claustrophobia, or obesity. CONCLUSIONS: With the increasing availability of MRI scanners in Canada, better understanding of the indications, contraindications, and risks will be helpful for family physicians and their patients. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 PMID:10509224

  5. Triaxial magnetic field gradient system for microcoil magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Seeber, D. A.; Hoftiezer, J. H.; Daniel, W. B.; Rutgers, M. A.; Pennington, C. H.

    2000-11-01

    There is a great advantage in signal to noise ratio (S/N) that can be obtained in nuclear magnetic resonance (NMR) experiments on very small samples (having spatial dimensions ˜100 μm or less) if one employs NMR "micro" receiver coils, "microcoils," which are of similarly small dimensions. The gains in S/N could enable magnetic resonance imaging (MRI) microscopy with spatial resolution of ˜1-2 μm, much better than currently available. Such MRI microscopy however requires very strong (>10 T/m), rapidly switchable triaxial magnetic field gradients. Here, we report the design and construction of such a triaxial gradient system, producing gradients substantially greater than 15 T/m in all three directions, x, y, and z (and as high as 50 T/m for the x direction). The gradients are switchable within time ˜10 μs and adequately uniform (within 5% over a volume of [600μm3] for microcoil MRI of small samples.

  6. Acoustic noise during functional magnetic resonance imaging.

    PubMed

    Ravicz, M E; Melcher, J R; Kiang, N Y

    2000-10-01

    Functional magnetic resonance imaging (fMRI) enables sites of brain activation to be localized in human subjects. For studies of the auditory system, acoustic noise generated during fMRI can interfere with assessments of this activation by introducing uncontrolled extraneous sounds. As a first step toward reducing the noise during fMRI, this paper describes the temporal and spectral characteristics of the noise present under typical fMRI study conditions for two imagers with different static magnetic field strengths. Peak noise levels were 123 and 138 dB re 20 microPa in a 1.5-tesla (T) and a 3-T imager, respectively. The noise spectrum (calculated over a 10-ms window coinciding with the highest-amplitude noise) showed a prominent maximum at 1 kHz for the 1.5-T imager (115 dB SPL) and at 1.4 kHz for the 3-T imager (131 dB SPL). The frequency content and timing of the most intense noise components indicated that the noise was primarily attributable to the readout gradients in the imaging pulse sequence. The noise persisted above background levels for 300-500 ms after gradient activity ceased, indicating that resonating structures in the imager or noise reverberating in the imager room were also factors. The gradient noise waveform was highly repeatable. In addition, the coolant pump for the imager's permanent magnet and the room air-handling system were sources of ongoing noise lower in both level and frequency than gradient coil noise. Knowledge of the sources and characteristics of the noise enabled the examination of general approaches to noise control that could be applied to reduce the unwanted noise during fMRI sessions.

  7. BROADBAND EXCITATION IN NUCLEAR MAGNETIC RESONANCE

    SciTech Connect

    Tycko, R.

    1984-10-01

    Theoretical methods for designing sequences of radio frequency (rf) radiation pulses for broadband excitation of spin systems in nuclear magnetic resonance (NMR) are described. The sequences excite spins uniformly over large ranges of resonant frequencies arising from static magnetic field inhomogeneity, chemical shift differences, or spin couplings, or over large ranges of rf field amplitudes. Specific sequences for creating a population inversion or transverse magnetization are derived and demonstrated experimentally in liquid and solid state NMR. One approach to broadband excitation is based on principles of coherent averaging theory. A general formalism for deriving pulse sequences is given, along with computational methods for specific cases. This approach leads to sequences that produce strictly constant transformations of a spin system. The importance of this feature in NMR applications is discussed. A second approach to broadband excitation makes use of iterative schemes, i.e. sets of operations that are applied repetitively to a given initial pulse sequences, generating a series of increasingly complex sequences with increasingly desirable properties. A general mathematical framework for analyzing iterative schemes is developed. An iterative scheme is treated as a function that acts on a space of operators corresponding to the transformations produced by all possible pulse sequences. The fixed points of the function and the stability of the fixed points are shown to determine the essential behavior of the scheme. Iterative schemes for broadband population inversion are treated in detail. Algebraic and numerical methods for performing the mathematical analysis are presented. Two additional topics are treated. The first is the construction of sequences for uniform excitation of double-quantum coherence and for uniform polarization transfer over a range of spin couplings. Double-quantum excitation sequences are demonstrated in a liquid crystal system. The

  8. Stable cerasomes for simultaneous drug delivery and magnetic resonance imaging.

    PubMed

    Cao, Zhong; Zhu, Wenjian; Wang, Wei; Zhang, Chunyang; Xu, Ming; Liu, Jie; Feng, Shi-Ting; Jiang, Qing; Xie, Xiaoyan

    2014-01-01

    Magnetic liposomes have been frequently used as nanocarriers for targeted drug delivery and magnetic resonance imaging in recent years. Despite great potentials, their morphological/structural instability in the physiological environment still remains an intractable challenge for clinical applications. In this study, stable hybrid liposomal cerasomes (ie, liposomes partially coated with silica) which can co-encapsulate Fe3O4 nanoparticles and the anticancer drug paclitaxel were developed using thin film hydration method. Compared with the drug loaded liposomes, the paclitaxel-loaded magnetic cerasomes (PLMCs) exhibited much higher storage stability and better sustained release behavior. Cellular uptake study showed that the utilization of an external magnetic field significantly facilitated the internalization of PLMCs into cancer cells, resulting in potentiated drug efficacy of killing tumor cells. The T2 relaxivity (r2) of our PLMCs was much higher than that of free Fe3O4 nanoparticles, suggesting increased sensitivity in T2-weighted imaging. Given its excellent biocompatibility also shown in the study, such dual functional PLMC is potentially a promising nanosystem for effective cancer diagnosis and therapy.

  9. Multidataset Refinement Resonant Diffraction, and Magnetic Structures

    PubMed Central

    Attfield, J. Paul

    2004-01-01

    The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset refinement is now commonplace; the datasets may be from different detectors, e.g., in a time-of-flight experiment, or from separate experiments, such as at several x-ray energies giving resonant information. The complementary use of x rays and neutrons is exemplified by a recent combined refinement of the monoclinic superstructure of magnetite, Fe3O4, below the 122 K Verwey transition, which reveals evidence for Fe2+/Fe3+ charge ordering. Powder neutron diffraction data continue to be used for the solution and Rietveld refinement of magnetic structures. Time-of-flight instruments on cold neutron sources can produce data that have a high intensity and good resolution at high d-spacings. Such profiles have been used to study incommensurate magnetic structures such as FeAsO4 and β–CrPO4. A multiphase, multidataset refinement of the phase-separated perovskite (Pr0.35Y0.07Th0.04Ca0.04Sr0.5)MnO3 has been used to fit three components with different crystal and magnetic structures at low temperatures. PMID:27366599

  10. Ferromagnetic resonance of particulate magnetic recording tapes

    NASA Astrophysics Data System (ADS)

    Netzelmann, U.

    1990-08-01

    The room-temperature ferromagnetic resonance (FMR) spectra of γ-Fe2O3, CrO2, and barium ferrite particulate magnetic recording tapes have been measured at microwave frequencies of 9.35 and 35 GHz for various orientations of the static and high-frequency magnetic fields with respect to the tape. For CrO2 tapes, the influence of the width of the angular distribution of the particle orientations on the FMR spectra has been studied from the nearly isotropic case up to the highly oriented case. Hysteretic behavior for a CrO2 tape as well as the effect of tape calendering for a γ-Fe2O3 tape has been observed by FMR. Experimental results are found to be in reasonable agreement with results of theoretical calculations based on a model of an ellipsoidal single-domain particle with both shape and magnetocrystalline anisotropy. Magnetostatic interaction inside the magnetic film has been introduced by expressing the total magnetostatic energy as a combination of a part dependent on particle shape and a part dependent on the shape of the tape. As a result of a comparison of experimental data with calculated data from the model, the magnetocrystalline easy axis of the CrO2 particles is found to be parallel with the particle axis.

  11. Magnetic resonance spectroscopy and metabolic imaging in white matter diseases and pediatric disorders.

    PubMed

    Cecil, Kim M; Kos, Radmila Savcic

    2006-08-01

    This review provides the reader with an overview of the magnetic resonance spectroscopy technique and the clinical, pathological, imaging, and metabolic features for select white matter disorders of interest. With this composite summary, the reader should find it easier to implement and interpret spectroscopy in the clinical setting for the diagnosis and monitoring of patients with white matter disorders.

  12. Clear Depiction of Inflammatory Abdominal Aortic Aneurysm with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Orta Kilickesmez, Kadriye; Kilickesmez, Ozgur

    2010-04-15

    We report the case of an inflammatory abdominal aortic aneurysm incidentally detected clearly with diffusion-weighted magnetic resonance imaging (DW-MRI) during the examination of a patient with myelofibrosis with myeloid metaplasia that later converted to acute myeloid leukemia. DW-MRI revealed a hyperintense halo surrounding the abdominal aorta with aneurysmatic dilatation, establishing the diagnosis.

  13. Double inversion recovery magnetic resonance imaging of subcortical band heterotopia: a report of 2 cases.

    PubMed

    Zhang, Quan; Zhang, Yunting; Zhang, Jing; Li, Qiong

    2011-01-01

    We report 2 cases of subcortical band heterotopia (SBH) with emphasis on double inversion recovery (DIR) magnetic resonance imaging (MRI). The heterotopic gray matter demonstrated homogeneous high signal intensity and the delineation between the SBH and white matter was distinctly depicted on DIR MRI. Double inversion recovery is a useful adjunct to conventional MRI for the diagnosis of SBH.

  14. [Preoperative full-body magnetic resonance imaging is indicated on suspicion of multifocal infection in children].

    PubMed

    Al-Aubaidi, Zaid; Pedersen, Niels Wisbech

    2011-04-11

    Musculoskeletal infections in children present a challenge regarding diagnosis and treatment. Conventional radiographs guide the initial radiographic assessment. Additional imaging is often performed to improve the diagnosis of the abnormality. The modalities used are ultrasound, bone-scan, computed tomography or magnetic resonance imaging (MRI). On suspicion of multifocal musculoskeletal infections (MMI), MRI may save time and improve preoperative planning. We highly recommend the use of MRI for the preoperative assessment of children with MMI.

  15. Magnetic resonance tracking of fluorescent nanodiamond fabrication

    NASA Astrophysics Data System (ADS)

    Shames, A. I.; Osipov, V. Yu; Boudou, J. P.; Panich, A. M.; von Bardeleben, H. J.; Treussart, F.; Vul', A. Ya

    2015-04-01

    Magnetic resonance techniques (electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR)) are used for tracking the multi-stage process of the fabrication of fluorescent nanodiamonds (NDs) produced by high-energy electron irradiation, annealing, and subsequent nano-milling. Pristine commercial high pressure and high temperature microdiamonds (MDs) with mean size 150 μm contain ~5  ×  1018 spins/g of singlet (S = 1/2) substitutional nitrogen defects P1, as well as sp3 C-C dangling bonds in the crystalline lattice. The half-field X-band EPR clearly shows (by the appearance of the intense ‘forbidden’ g = 4.26 line) that high-energy electron irradiation and annealing of MDs induce a large amount (~5  ×  1017 spins/g) of triplet (S = 1) magnetic centers, which are identified as negatively charged nitrogen vacancy defects (NV-). This is supported by EPR observations of the ‘allowed’ transitions between Zeeman sublevels of the triplet state. After progressive milling of the fluorescent MDs down to an ultrasubmicron scale (≤100 nm), the relative abundance of EPR active NV- defects in the resulting fluorescent NDs (FND) substantially decreases and, vice versa, the content of C-inherited singlet defects correlatively increases. In the fraction of the finest FNDs (mean particle size <20 nm), which are contained in the dried supernatant of ultracentrifuged aqueous dispersion of FNDs, the NV- content is found to be reduced by one order of magnitude whereas the singlet defects content increases up to ~2  ×  1019 spins/g. In addition, another triplet-type defect, which is characterized by the g = 4.00 ‘forbidden’ line, appears. On reduction of the particle size below the 20 nm limit, the ‘allowed’ EPR lines become practically unobservable, whereas the ‘forbidden’ lines remain as a reliable fingerprint of the presence of NV- centers in small ND systems. The same size reduction causes the disappearance of the

  16. Nuclear magnetic resonance studies of lens transparency

    SciTech Connect

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ({sup 31}P) NMR spectroscopy was used to measure the {sup 31}P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. {sup 1}H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T{sub 1} and T{sub 2} with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T{sub 1} and T{sub 2} at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T{sub 1} or T{sub 2}, consistent with the phase separation being a low-energy process. {sup 1}H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T{sub 1} relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine {gamma}-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T{sub 1} with increasing magnetic field.

  17. Stem cell labeling for magnetic resonance imaging.

    PubMed

    Himmelreich, Uwe; Hoehn, Mathias

    2008-01-01

    In vivo applications of cells for the monitoring of their cell dynamics increasingly use non-invasive magnetic resonance imaging. This imaging modality allows in particular to follow the migrational activity of stem cells intended for cell therapy strategies. All these approaches require the prior labeling of the cells under investigation for excellent contrast against the host tissue background in the imaging modality. The present review discusses the various routes of cell labeling and describes the potential to observe both cell localization and their cell-specific function in vivo. Possibilities for labeling strategies, pros and cons of various contrast agents are pointed out while potential ambiguities or problems of labeling strategies are emphasized.

  18. Infected aortoiliofemoral grafts: magnetic resonance imaging.

    PubMed

    Justich, E; Amparo, E G; Hricak, H; Higgins, C B

    1985-01-01

    Three patients with proved infected aortoiliofemoral grafts were examined by magnetic resonance (MR) imaging using a spin echo technique. MR clearly identified the perigraft abscess, the involvement of adjacent structures, and the longitudinal extent of the process in all patients. The MR findings were: Abscesses create a high signal intensity, somewhat less than fat. The perigraft abscess has a great contrast with the signal void of flowing blood in the graft. Inflammatory changes cause an inhomogeneous intermediate signal, slightly more intense than muscle. Both abscesses and edematous areas increase their signal intensity with long repetition rates and long echo delays. Areas of gas appear black. They cannot be distinguished from calcified plaques. Additional information is gained about the graft patency. Although the specificity has to be proved, MR imaging is sensitive in the detection of infected grafts and for defining the longitudinal extent of the perigraft abscess.

  19. Nuclear magnetic resonance imaging in medicine

    PubMed Central

    McKinstry, C S

    1986-01-01

    Using the technique of nuclear magnetic resonance (NMR, MR, MRI), the first images displaying pathology in humans were published in 1980.1 Since then, there has been a rapid extension in the use of the technique, with an estimated 225 machines in use in the USA at the end of 1985.2 Considerable enthusiasm has been expressed for this new imaging technique,3 although awareness of its high cost in the present economic climate has led to reservations being expressed in other quarters.2 The aim of this article is to give an outline of the present state of NMR, and indicate some possible future developments. ImagesFig 1Fig 2Fig 3(a)Fig 3 (b)Fig 4Fig 5Fig 6Fig 7 (a)Fig 7 (b)Fig 8Fig 9Fig 10 PMID:3811023

  20. Cardiovascular magnetic resonance: deeper insights through bioengineering.

    PubMed

    Young, A A; Prince, J L

    2013-01-01

    Heart disease is the main cause of morbidity and mortality worldwide, with coronary artery disease, diabetes, and obesity being major contributing factors. Cardiovascular magnetic resonance (CMR) can provide a wealth of quantitative information on the performance of the heart, without risk to the patient. Quantitative analyses of these data can substantially augment the diagnostic quality of CMR examinations and can lead to more effective characterization of disease and quantification of treatment benefit. This review provides an overview of the current state of the art in CMR with particular regard to the quantification of motion, both microscopic and macroscopic, and the application of bioengineering analysis for the evaluation of cardiac mechanics. We discuss the current clinical practice and the likely advances in the next 5-10 years, as well as the ways in which clinical examinations can be augmented by bioengineering analysis of strain, compliance, and stress.

  1. Magnetic resonance imaging after exposure to microgravity

    NASA Technical Reports Server (NTRS)

    Leblanc, Adrian

    1993-01-01

    A number of physiological changes were demonstrated in bone, muscle, and blood from exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long-duration space missions is an important NASA goal. Historically, NASA has had to rely on tape measures, x-ray, and metabolic balance studies with collection of excreta and blood specimens to obtain this information. The development of magnetic resonance imaging (MRI) offers the possibility of greatly extending these early studies in ways not previously possible; MRI is also non-invasive and safe; i.e., no radiation exposure. MRI provides both superb anatomical images for volume measurements of individual structures and quantification of chemical/physical changes induced in the examined tissues. This investigation will apply MRI technology to measure muscle, intervertebral disc, and bone marrow changes resulting from exposure to microgravity.

  2. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Evans, H.; Bryan, R. N.; Johnson, P.; Schonfeld, E.; Jhingran, S. G.

    1984-01-01

    A number of physiological changes have been demonstrated in bone, muscle and blood after exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long duration space missions is an important NASA goal. The advent of tomographic nuclear magnetic resonance imaging (NMR or MRI) gives NASA a way to greatly extend early studies of this phenomena in ways not previously possible; NMR is also noninvasive and safe. NMR provides both superb anatomical images for volume assessments of individual organs and quantification of chemical/physical changes induced in the examined tissues. The feasibility of NMR as a tool for human physiological research as it is affected by microgravity is demonstrated. The animal studies employed the rear limb suspended rat as a model of mucle atrophy that results from microgravity. And bedrest of normal male subjects was used to simulate the effects of microgravity on bone and muscle.

  3. A novel digital magnetic resonance imaging spectrometer.

    PubMed

    Liu, Zhengmin; Zhao, Cong; Zhou, Heqin; Feng, Huanqing

    2006-01-01

    Spectrometer is the essential part of magnetic resonance imaging (MRI) system. It controls the transmitting and receiving of signals. Many commercial spectrometers are now available. However, they are usually costly and complex. In this paper, a new digital spectrometer based on PCI extensions for instrumentation (PXI) architecture is presented. Radio frequency (RF) pulse is generated with the method of digital synthesis and its frequency and phase are continuously tunable. MR signal acquired by receiver coils is processed by digital quadrature detection and filtered to get the k-space data, which avoid the spectral distortion due to amplitude and phase errors between two channels of traditional detection. Compared to the conventional design, the presented spectrometer is built with general PXI platform and boards. This design works in a digital manner with features of low cost, high performance and accuracy. The experiments demonstrate its efficiency.

  4. Myocardial Tissue Characterization by Magnetic Resonance Imaging

    PubMed Central

    Ferreira, Vanessa M.; Piechnik, Stefan K.; Robson, Matthew D.; Neubauer, Stefan

    2014-01-01

    Cardiac magnetic resonance (CMR) imaging is a well-established noninvasive imaging modality in clinical cardiology. Its unsurpassed accuracy in defining cardiac morphology and function and its ability to provide tissue characterization make it well suited for the study of patients with cardiac diseases. Late gadolinium enhancement was a major advancement in the development of tissue characterization techniques, allowing the unique ability of CMR to differentiate ischemic heart disease from nonischemic cardiomyopathies. Using T2-weighted techniques, areas of edema and inflammation can be identified in the myocardium. A new generation of myocardial mapping techniques are emerging, enabling direct quantitative assessment of myocardial tissue properties in absolute terms. This review will summarize recent developments involving T1-mapping and T2-mapping techniques and focus on the clinical applications and future potential of these evolving CMR methodologies. PMID:24576837

  5. Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) project

    NASA Astrophysics Data System (ADS)

    Spaniol, Craig

    1993-06-01

    The West Virginia State College Community College Division NASA Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) study is described. During this contract period, the two most significant and professionally rewarding events were the presentation of the research activity at the Sir Isaac Newton Conference in St. Petersburg, Russia, and the second Day of Discovery Conference, focusing on economic recovery in West Virginia. An active antenna concept utilizing a signal feedback principle similar to regenerative receivers used in early radio was studied. The device has potential for ELF research and other commercial applications for improved signal reception. Finally, work continues to progress on the development of a prototype monitoring station. Signal monitoring, data display, and data storage are major areas of activity. In addition, we plan to continue our dissemination of research activity through presentations at seminars and other universities.

  6. Magnetic resonance imaging of experimental cerebral oedema.

    PubMed Central

    Barnes, D; McDonald, W I; Tofts, P S; Johnson, G; Landon, D N

    1986-01-01

    Triethyl tin(TET)-induced cerebral oedema has been studied in cats by magnetic resonance imaging (MRI), and the findings correlated with the histology and fine structure of the cerebrum following perfusion-fixation. MRI is a sensitive technique for detecting cerebral oedema, and the distribution and severity of the changes correlate closely with the morphological abnormalities. The relaxation times, T1 and T2 increase progressively as the oedema develops, and the proportional increase in T2 is approximately twice that in T1. Analysis of the magnetisation decay curves reveals slowly-relaxing and rapidly-relaxing components which probably correspond to oedema fluid and intracellular water respectively. The image appearances taken in conjunction with relaxation data provide a basis for determining the nature of the oedema in vivo. Images PMID:3806109

  7. Small-Volume Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fratila, Raluca M.; Velders, Aldrik H.

    2011-07-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most information-rich analytical techniques available. However, it is also inherently insensitive, and this drawback precludes the application of NMR spectroscopy to mass- and volume-limited samples. We review a particular approach to increase the sensitivity of NMR experiments, namely the use of miniaturized coils. When the size of the coil is reduced, the sample volume can be brought down to the nanoliter range. We compare the main coil geometries (solenoidal, planar, and microslot/stripline) and discuss their applications to the analysis of mass-limited samples. We also provide an overview of the hyphenation of microcoil NMR spectroscopy to separation techniques and of the integration with lab-on-a-chip devices and microreactors.

  8. Maximum Likelihood Reconstruction for Magnetic Resonance Fingerprinting

    PubMed Central

    Zhao, Bo; Setsompop, Kawin; Ye, Huihui; Cauley, Stephen; Wald, Lawrence L.

    2017-01-01

    This paper introduces a statistical estimation framework for magnetic resonance (MR) fingerprinting, a recently proposed quantitative imaging paradigm. Within this framework, we present a maximum likelihood (ML) formalism to estimate multiple parameter maps directly from highly undersampled, noisy k-space data. A novel algorithm, based on variable splitting, the alternating direction method of multipliers, and the variable projection method, is developed to solve the resulting optimization problem. Representative results from both simulations and in vivo experiments demonstrate that the proposed approach yields significantly improved accuracy in parameter estimation, compared to the conventional MR fingerprinting reconstruction. Moreover, the proposed framework provides new theoretical insights into the conventional approach. We show analytically that the conventional approach is an approximation to the ML reconstruction; more precisely, it is exactly equivalent to the first iteration of the proposed algorithm for the ML reconstruction, provided that a gridding reconstruction is used as an initialization. PMID:26915119

  9. Magnetic resonance image segmentation using multifractal techniques

    NASA Astrophysics Data System (ADS)

    Yu, Yue-e.; Wang, Fang; Liu, Li-lin

    2015-11-01

    In order to delineate target region for magnetic resonance image (MRI) with diseases, the classical multifractal spectrum (MFS)-segmentation method and latest multifractal detrended fluctuation spectrum (MF-DFS)-based segmentation method are employed in our study. One of our main conclusions from experiments is that both of the two multifractal-based methods are workable for handling MRIs. The best result is obtained by MF-DFS-based method using Lh10 as local characteristic. The anti-noises experiments also suppot the conclusion. This interest finding shows that the features can be better represented by the strong fluctuations instead of the weak fluctuations for the MRIs. By comparing the multifractal nature between lesion and non-lesion area on the basis of the segmentation results, an interest finding is that the gray value's fluctuation in lesion area is much severer than that in non-lesion area.

  10. Advanced magnetic resonance imaging of neurodegenerative diseases.

    PubMed

    Agosta, Federica; Galantucci, Sebastiano; Filippi, Massimo

    2017-01-01

    Magnetic resonance imaging (MRI) is playing an increasingly important role in the study of neurodegenerative diseases, delineating the structural and functional alterations determined by these conditions. Advanced MRI techniques are of special interest for their potential to characterize the signature of each neurodegenerative condition and aid both the diagnostic process and the monitoring of disease progression. This aspect will become crucial when disease-modifying (personalized) therapies will be established. MRI techniques are very diverse and go from the visual inspection of MRI scans to more complex approaches, such as manual and automatic volume measurements, diffusion tensor MRI, and functional MRI. All these techniques allow us to investigate the different features of neurodegeneration. In this review, we summarize the most recent advances concerning the use of MRI in some of the most important neurodegenerative conditions, putting an emphasis on the advanced techniques.

  11. Bilateral filtering of magnetic resonance phase images.

    PubMed

    McPhee, Kelly C; Denk, Christian; Al-Rekabi, Zeinab; Rauscher, Alexander

    2011-09-01

    High-pass filtering is required for the removal of background field inhomogeneities in magnetic resonance phase images. This high-pass filtering smooths across boundaries between areas with large differences in phase. The most prominent boundary is the surface of the brain where areas with large phase values inside the brain are located close to areas outside the brain where the phase is, on average, zero. Cortical areas, which are of great interest in brain MRI, are therefore often degraded by high-pass filtering. Here, we propose the use of the bilateral filter for the high-pass filtering step. The bilateral filter is essentially a Gaussian filter that stops smoothing at boundaries. We show that the bilateral filter improves image quality at the brain's surface, without sacrificing contrast within the brain.

  12. Geochemical Controls on Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Knight, Rosemary; Prasad, Manika; Keating, Kristina

    2003-11-11

    OAK-B135 Our research objectives are to determine, through an extensive set of laboratory experiments, the effect of the specific mineralogic form of iron and the effect of the distribution of iron on proton nuclear magnetic resonance (NMR) relaxation mechanisms. In the first nine months of this project, we have refined the experimental procedures to be used in the acquisition of the laboratory NMR data; have ordered, and conducted preliminary measurements on, the sand samples to be used in the experimental work; and have revised and completed the theoretical model to use in this project. Over the next year, our focus will be on completing the first phase of the experimental work where the form and distribution of the iron in the sands in varied.

  13. Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) project

    NASA Technical Reports Server (NTRS)

    Spaniol, Craig

    1993-01-01

    The West Virginia State College Community College Division NASA Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) study is described. During this contract period, the two most significant and professionally rewarding events were the presentation of the research activity at the Sir Isaac Newton Conference in St. Petersburg, Russia, and the second Day of Discovery Conference, focusing on economic recovery in West Virginia. An active antenna concept utilizing a signal feedback principle similar to regenerative receivers used in early radio was studied. The device has potential for ELF research and other commercial applications for improved signal reception. Finally, work continues to progress on the development of a prototype monitoring station. Signal monitoring, data display, and data storage are major areas of activity. In addition, we plan to continue our dissemination of research activity through presentations at seminars and other universities.

  14. Magnetic resonance imaging of optic nerve

    PubMed Central

    Gala, Foram

    2015-01-01

    Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies. PMID:26752822

  15. Chronic subdural hematoma: demonstration by magnetic resonance

    SciTech Connect

    Sipponen, J.T.; Sepponen, R.E.; Sivula, A.

    1984-01-01

    The ability of magnetic resonance (MR) to identify intracranial hematomas was tested in five patients with clinical and computed tomographic signs of chronic subdural hematoma. The extracerebral collections were displayed as a zone of bright intensity using the T1-weighted inversion recovery (IR 1500/400) sequence, reflecting the lesions' short T1 relaxation times. The collections also showed high intensity using the spin echo (SE) sequence, with a longer delay of 100ms and 160ms, reflecting the long T2 relaxation time. The spin echo sequence with a repetition time of 500ms and an echo delay of 160ms (SE 500/160) almost effaced other structures in the image, thus increasing the specificity of this pulse scheme for detection of chronic blood collections. Although in two of the five patients the subdural hematomas were in the isodense CT phase, all were easily visualized with MR.

  16. Functional magnetic resonance imaging studies of language.

    PubMed

    Small, Steven L; Burton, Martha W

    2002-11-01

    Functional neuroimaging of language builds on almost 150 years of study in neurology, psychology, linguistics, anatomy, and physiology. In recent years, there has been an explosion of research using functional imaging technology, especially positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), to understand the relationship between brain mechanisms and language processing. These methods combine high-resolution anatomic images with measures of language-specific brain activity to reveal neural correlates of language processing. This article reviews some of what has been learned about the neuroanatomy of language from these imaging techniques. We first discuss the normal case, organizing the presentation according to the levels of language, encompassing words (lexicon), sound structure (phonemes), and sentences (syntax and semantics). Next, we delve into some unusual language processing circumstances, including second languages and sign languages. Finally, we discuss abnormal language processing, including developmental and acquired dyslexia and aphasia.

  17. Cardiac magnetic resonance imaging: patient safety considerations.

    PubMed

    Giroletti, Elio; Corbucci, Giorgio

    Magnetic Resonance Imaging (MRI) is widely used in medicine. In cardiology, it is used to assess congenital or acquired diseases of the heat: and large vessels. Unless proper precautions are taken, it is generally advisable to avoid using this technique in patients with implanted electronic stimulators, such as pacemakers and defibrillators, on account of the potential risk of inducing electrical currents on the endocardial catheters, since these currents might stimulate the heart at a high frequency, thereby triggering dangerous arrhythmias. In addition to providing some basic information on pacemakers, defibrillators and MRI, and on the possible physical phenomena that may produce harmful effects, the present review examines the indications given in the literature, with particular reference to coronary stents, artificial heart valves and implantable cardiac stimulators.

  18. Geometric Computation of Human Gyrification Indexes from Magnetic Resonance Images

    DTIC Science & Technology

    2009-04-01

    GEOMETRIC COMPUTATION OF HUMAN GYRIFICATION INDEXES FROM MAGNETIC RESONANCE IMAGES By Shu Su Tonya White Marcus Schmidt Chiu-Yen Kao and Guillermo...00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Geometric Computation of Human Gyrification Indexes from Magnetic Resonance Images 5a. CONTRACT NUMBER... Geometric Computation of Gyrification Indexes Chiu-Yen Kao 1 Geometric Computation of Human Gyrification

  19. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    SciTech Connect

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  20. Selectivity in multiple quantum nuclear magnetic resonance

    SciTech Connect

    Warren, W.S.

    1980-11-01

    The observation of multiple-quantum nuclear magnetic resonance transitions in isotropic or anisotropic liquids is shown to give readily interpretable information on molecular configurations, rates of motional processes, and intramolecular interactions. However, the observed intensity of high multiple-quantum transitions falls off dramatically as the number of coupled spins increases. The theory of multiple-quantum NMR is developed through the density matrix formalism, and exact intensities are derived for several cases (isotropic first-order systems and anisotropic systems with high symmetry) to shown that this intensity decrease is expected if standard multiple-quantum pulse sequences are used. New pulse sequences are developed which excite coherences and produce population inversions only between selected states, even though other transitions are simultaneously resonant. One type of selective excitation presented only allows molecules to absorb and emit photons in groups of n. Coherent averaging theory is extended to describe these selective sequences, and to design sequences which are selective to arbitrarily high order in the Magnus expansion. This theory and computer calculations both show that extremely good selectivity and large signal enhancements are possible.

  1. Compact electrically detected magnetic resonance setup

    NASA Astrophysics Data System (ADS)

    Eckardt, Michael; Behrends, Jan; Münter, Detlef; Harneit, Wolfgang

    2015-04-01

    Electrically detected magnetic resonance (EDMR) is a commonly used technique for the study of spin-dependent transport processes in semiconductor materials and electro-optical devices. Here, we present the design and implementation of a compact setup to measure EDMR, which is based on a commercially available benchtop electron paramagnetic resonance (EPR) spectrometer. The electrical detection part uses mostly off-the-shelf electrical components and is thus highly customizable. We present a characterization and calibration procedure for the instrument that allowed us to quantitatively reproduce results obtained on a silicon-based reference sample with a "large-scale" state-of-the-art instrument. This shows that EDMR can be used in novel contexts relevant for semiconductor device fabrication like clean room environments and even glove boxes. As an application example, we present data on a class of environment-sensitive objects new to EDMR, semiconducting organic microcrystals, and discuss similarities and differences to data obtained for thin-film devices of the same molecule.

  2. Compact electrically detected magnetic resonance setup

    SciTech Connect

    Eckardt, Michael Harneit, Wolfgang; Behrends, Jan; Münter, Detlef

    2015-04-15

    Electrically detected magnetic resonance (EDMR) is a commonly used technique for the study of spin-dependent transport processes in semiconductor materials and electro-optical devices. Here, we present the design and implementation of a compact setup to measure EDMR, which is based on a commercially available benchtop electron paramagnetic resonance (EPR) spectrometer. The electrical detection part uses mostly off-the-shelf electrical components and is thus highly customizable. We present a characterization and calibration procedure for the instrument that allowed us to quantitatively reproduce results obtained on a silicon-based reference sample with a “large-scale” state-of-the-art instrument. This shows that EDMR can be used in novel contexts relevant for semiconductor device fabrication like clean room environments and even glove boxes. As an application example, we present data on a class of environment-sensitive objects new to EDMR, semiconducting organic microcrystals, and discuss similarities and differences to data obtained for thin-film devices of the same molecule.

  3. Rotational resonance of nonaxisymmetric magnetic braking in the KSTAR tokamak.

    PubMed

    Park, J-K; Jeon, Y M; Menard, J E; Ko, W H; Lee, S G; Bae, Y S; Joung, M; You, K-I; Lee, K-D; Logan, N; Kim, K; Ko, J S; Yoon, S W; Hahn, S H; Kim, J H; Kim, W C; Oh, Y-K; Kwak, J-G

    2013-08-30

    One of the important rotational resonances in nonaxisymmetric neoclassical transport has been experimentally validated in the KSTAR tokamak by applying highly nonresonant n=1 magnetic perturbations to rapidly rotating plasmas. These so-called bounce-harmonic resonances are expected to occur in the presence of magnetic braking perturbations when the toroidal rotation is fast enough to resonate with periodic parallel motions of trapped particles. The predicted and observed resonant peak along with the toroidal rotation implies that the toroidal rotation in tokamaks can be controlled naturally in favorable conditions to stability, using nonaxisymmetric magnetic perturbations.

  4. Magnetic tuning of electrically resonant metamaterial with inclusion of ferrite

    NASA Astrophysics Data System (ADS)

    Kang, Lei; Zhao, Qian; Zhao, Hongjie; Zhou, Ji

    2008-10-01

    We experimentally demonstrate a magnetic tuning of electrically resonant metamaterial (EMM) at microwave frequencies by introducing microwave ferrite rods into the periodic array of electrically resonant element. Different from those based on controlling the capacitance of equivalent LC circuit, this tunability arises from a mechanism of magnetically tuning the inductance of resonant element via the active ambient effective permeability. For magnetic fields from 0 to 5000 Oe, resonance frequency of the EMM can be continuously and reversibly tuned in a range of about 800 MHz. The active effective permittivity has also been investigated through the simulated scattering parameters.

  5. Pediatric Magnetic Resonance Enterography: Focused on Crohn's Disease

    PubMed Central

    Lee, So Mi; Choi, Young Hun

    2015-01-01

    Crohn's disease is a chronic idiopathic inflammatory disease of the intestines characterized by frequent relapse and remission. It often develops in children and adolescents, who are vulnerable to repeated exposure to ionizing radiations. Magnetic resonance enterography (MRE) is an increasingly important radiation-free imaging modality that is used to evaluate pediatric patients with Crohn's disease. MRE can evaluate extraluminal and extraintestinal abnormalities as well as the status of the bowel wall. In addition, MRE has an advantage in the evaluation of the small bowel involvement. MRE can be used for the initial diagnosis of Crohn's disease, and can aid in the assessment of disease activity and complications such as penetrating and fibrostenotic diseases. The aims of this article are to review the MRE technique for obtaining diagnostic and high-quality images and to discuss interpretations of imaging findings in patients with Crohn's disease. PMID:26473134

  6. Blood pool contrast agents for venous magnetic resonance imaging

    PubMed Central

    Oliveira, Irai S.; Li, Weier; Ganguli, Suvranu; Prabhakar, Anand M.

    2016-01-01

    Imaging of the venous system plays a vital role in the diagnosis and management of a wide range of clinically significant disorders. There have been great advances in venous imaging techniques, culminating in the use of magnetic resonance venography (MRV). Although MRV has distinct advantages in anatomic and quantitative cross sectional imaging without ionizing radiation, there are well-known challenges in acquisition timing and contrast administration in patients with renal impairment. The latest advancement involves the addition of new contrast media agents, which have emerged as valuable alternatives in these difficult scenarios. In this review, we will focus on a group of specific contrast agents called blood pool agents and discuss their salient features and clinical applications. PMID:28123972

  7. Magnetic resonance imaging of pediatric soft-tissue vascular anomalies.

    PubMed

    Navarro, Oscar M

    2016-05-01

    Magnetic resonance (MR) imaging can be used in the management of pediatric soft-tissue vascular anomalies for diagnosing and assessing extent of lesions and for evaluating response to therapy. MR imaging studies often involve a combination of T1- and T2-weighted images in addition to MR angiography and fat-suppressed post-contrast sequences. The MR imaging features of these vascular anomalies when combined with clinical findings can aid in diagnosis. In cases of complex vascular malformations and syndromes associated with vascular anomalies, MR imaging can be used to evaluate accompanying soft-tissue and bone anomalies. This article reviews the MR imaging protocols and appearances of the most common pediatric soft-tissue vascular anomalies.

  8. Elbow magnetic resonance imaging: imaging anatomy and evaluation.

    PubMed

    Hauptfleisch, Jennifer; English, Collette; Murphy, Darra

    2015-04-01

    The elbow is a complex joint. Magnetic resonance imaging (MRI) is often the imaging modality of choice in the workup of elbow pain, especially in sports injuries and younger patients who often have either a history of a chronic repetitive strain such as the throwing athlete or a distinct traumatic injury. Traumatic injuries and alternative musculoskeletal pathologies can affect the ligaments, musculotendinous, cartilaginous, and osseous structures of the elbow as well as the 3 main nerves to the upper limb, and these structures are best assessed with MRI.Knowledge of the complex anatomy of the elbow joint as well as patterns of injury and disease is important for the radiologist to make an accurate diagnosis in the setting of elbow pain. This chapter will outline elbow anatomy, basic imaging parameters, compartmental pathology, and finally applications of some novel MRI techniques.

  9. Middle cerebellar peduncles: Magnetic resonance imaging and pathophysiologic correlate

    PubMed Central

    Morales, Humberto; Tomsick, Thomas

    2015-01-01

    We describe common and less common diseases that can cause magnetic resonance signal abnormalities of middle cerebellar peduncles (MCP), offering a systematic approach correlating imaging findings with clinical clues and pathologic mechanisms. Myelin abnormalities, different types of edema or neurodegenerative processes, can cause areas of abnormal T2 signal, variable enhancement, and patterns of diffusivity of MCP. Pathologies such as demyelinating disorders or certain neurodegenerative entities (e.g., multiple system atrophy or fragile X-associated tremor-ataxia syndrome) appear to have predilection for MCP. Careful evaluation of concomitant imaging findings in the brain or brainstem; and focused correlation with key clinical findings such as immunosuppression for progressive multifocal leukoencephalopahty; hypertension, post-transplant status or high dose chemotherapy for posterior reversible encephalopathy; electrolyte disorders for myelinolysis or suspected toxic-drug related encephalopathy; would yield an appropriate and accurate differential diagnosis in the majority of cases. PMID:26751508

  10. Nuclear magnetic resonance of iron and copper disease states

    SciTech Connect

    Runge, V.M.; Clanton, J.A.; Smith, F.W.; Hutchison, J.; Mallard, J.; Partain, C.L.; James, A.E. Jr.

    1983-11-01

    The tissue levels of paramagnetic ions are an important factor in the determination of T/sub 1/ values as observed by nuclear magnetic resonance (NMR) imaging. The increased levels of iron present in human disease states such as hemochromatosis lead to decreased T/sub 1/ values. The mean liver T/sub 1/ of three patients with iron storage disease was determined to be 130 msec, significantly different from the value of 154 msec, the mean for 14 normal controls. Whether NMR will be able to detect the increased copper levels in liver and brain in Wilson disease remains for further clinical trials to evaluate. NMR imaging, however, does serve as a noninvasive method for the diagnosis of states of iron overload and as a technique to follow progression of disease or response to medical therapy.

  11. Early magnetic resonance imaging control after temporomandibular joint arthrocentesis

    PubMed Central

    Ângelo, David Faustino; Sousa, Rita; Pinto, Isabel; Sanz, David; Gil, F. Monje; Salvado, Francisco

    2015-01-01

    Temporomandibular joint (TMJ) lysis and lavage arthrocentesis with viscosupplementation are an effective treatment for acute disc displacement (DD) without reduction. Clinical success seems to be related to multiple factors despite the lack of understanding of its mechanisms. The authors present a case report of 17-year-old women with acute open mouth limitation (12 mm), right TMJ pain-8/10 visual analog scale, right deviation when opening her mouth. The clinical and magnetic resonance imaging (MRI) diagnosis was acute DD without reduction of right TMJ. Right TMJ arthrocentesis was purposed to the patient with lysis, lavage, and viscosupplementation of the upper joint space. After 5 days, a new MRI was performed to confirm upper joint space distension and disc position. Clinical improvement was obtained 5 days and 1 month after arthrocentesis. Upper joint space increased 6 mm and the disc remained displaced. We report the first early TMJ MRI image postoperative, with measurable upper joint space. PMID:26981483

  12. New developments in magnetic resonance imaging of the nail unit.

    PubMed

    Soscia, Ernesto; Sirignano, Cesare; Catalano, Onofrio; Atteno, Mariangela; Costa, Luisa; Caso, Francesco; Peluso, Rosario; Bruner, Vincenzo; Aquino, Maria Maddalena; Del Puente, Antonio; Salvatore, Marco; Scarpa, Raffaele

    2012-07-01

    The evolution of dedicated magnetic resonance imaging (MRI) musculoskeletal equipment allows new sequences and better images of the nail unit. The use of MRI has modified the imaging strategies used in treating inflammatory arthritis. In the case of psoriatic arthritis (PsA), the MRI study of the nail unit identifies nail involvement, which appears as an initial lesion for the induction of distal phalanx damage and consequently of distal interphalangeal joint arthritis. All patients with psoriasis, even in the absence of a clinically evident onychopathy, show characteristic MRI changes in the nail. This evidence could have a practical diagnostic value, because MRI study of the nail could document diagnosis in patients with undifferentiated spondyloarthropathies who have a barely evident psoriasis. We discuss the advantages and problems related to the use of low-field and high-field MRI in the study of the nail unit of patients with PsA.

  13. Magnetic resonance imaging of nail unit in psoriatic arthritis.

    PubMed

    Soscia, Ernesto; Scarpa, Raffaele; Cimmino, Marco Amedeo; Atteno, Mariangela; Peluso, Rosario; Sirignano, Cesare; Costa, Luisa; Iervolino, Salvatore; Caso, Francesco; Del Puente, Antonio; Salvatore, Marco; Soricelli, Andrea

    2009-08-01

    The use of magnetic resonance imaging (MRI) has modified the imaging strategies of inflammatory arthritides. In psoriatic arthritis (PsA), MRI study of the nail unit identifies nail involvement that appears as the initial lesion for induction of distal phalanx damage and consequently of distal interphalangeal joint arthritis. All psoriatic patients, also in the absence of a clinically evident onychopathy, show characteristic MRI changes of the nail. This evidence could have practical diagnostic value because MRI study of the nail could document diagnosis in patients with undifferentiated spondyloarthropathies who have barely evident psoriasis. We discuss the advantages and problems related to the use of low- and high-field MRI in the study of the nail unit of patients with PsA.

  14. Early magnetic resonance imaging control after temporomandibular joint arthrocentesis.

    PubMed

    Ângelo, David Faustino; Sousa, Rita; Pinto, Isabel; Sanz, David; Gil, F Monje; Salvado, Francisco

    2015-01-01

    Temporomandibular joint (TMJ) lysis and lavage arthrocentesis with viscosupplementation are an effective treatment for acute disc displacement (DD) without reduction. Clinical success seems to be related to multiple factors despite the lack of understanding of its mechanisms. The authors present a case report of 17-year-old women with acute open mouth limitation (12 mm), right TMJ pain-8/10 visual analog scale, right deviation when opening her mouth. The clinical and magnetic resonance imaging (MRI) diagnosis was acute DD without reduction of right TMJ. Right TMJ arthrocentesis was purposed to the patient with lysis, lavage, and viscosupplementation of the upper joint space. After 5 days, a new MRI was performed to confirm upper joint space distension and disc position. Clinical improvement was obtained 5 days and 1 month after arthrocentesis. Upper joint space increased 6 mm and the disc remained displaced. We report the first early TMJ MRI image postoperative, with measurable upper joint space.

  15. [Cardiac magnetic resonance imaging of congenital heart defects in adults].

    PubMed

    Bastarrika Alemañ, G; Gavira Gómez, J J; Zudaire Díaz-Tejeiro, B; Castaño Rodríguez, S; Romero Ibarra, C; Sáenz de Buruaga, J D

    2007-01-01

    The study of congenital cardiopathies (CC) is one of the most clearly established indications of cardiac magnetic resonance imaging (CMRI). Different sequences, including anatomic, functional, flow (phase contrast), and 3D angiographic sequences, enable the diagnosis, treatment planning, and follow-up of these conditions. CMRI allows the anatomy, function, and alterations of flow in these cardiopathies to be evaluated in a single examination. Three-dimensional MR angiography enables the study of the great vessels and the anomalies associated to congenital heart defects in adults. This article describes an examination protocol and provides examples of MR images of the most common CC in adults: atrial septal defect, interventricular communication, atrioventricular canal, tetralogy of Fallot, transposition of the great arteries, congenitally corrected transposition of the great arteries, bicuspid aortic valve, subaortic stenosis, aortic coarctation, and Ebstein's anomaly.

  16. Plasma-induced magnetic responses during nonlinear dynamics of magnetic islands due to resonant magnetic perturbations

    SciTech Connect

    Nishimura, Seiya

    2014-12-15

    Resonant magnetic perturbations (RMPs) produce magnetic islands in toroidal plasmas. Self-healing (annihilation) of RMP-induced magnetic islands has been observed in helical systems, where a possible mechanism of the self-healing is shielding of RMP penetration by plasma flows, which is well known in tokamaks. Thus, fundamental physics of RMP shielding is commonly investigated in both tokamaks and helical systems. In order to check this mechanism, detailed informations of magnetic island phases are necessary. In experiments, measurement of radial magnetic responses is relatively easy. In this study, based on a theoretical model of rotating magnetic islands, behavior of radial magnetic fields during the self-healing is investigated. It is confirmed that flips of radial magnetic fields are typically observed during the self-healing. Such behavior of radial magnetic responses is also observed in LHD experiments.

  17. Torque-mixing magnetic resonance spectroscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan T.; Diao, Zhu; Belov, Miro; Burgess, Jacob A.; Compton, Shawn R.; Hiebert, Wayne K.; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory E.; Thomson, Douglas J.; Freeman, Mark R.

    2016-10-01

    An optomechanical platform for magnetic resonance spectroscopy will be presented. The method relies on frequency mixing of orthogonal RF fields to yield a torque amplitude (arising from the transverse component of a precessing dipole moment, in analogy to magnetic resonance detection by electromagnetic induction) on a miniaturized resonant mechanical torsion sensor. In contrast to induction, the method is fully broadband and allows for simultaneous observation of the equilibrium net magnetic moment alongside the associated magnetization dynamics. To illustrate the method, comprehensive electron spin resonance spectra of a mesoscopic, single-crystal YIG disk at room temperature will be presented, along with situations where torque spectroscopy can offer complimentary information to existing magnetic resonance detection techniques. The authors are very grateful for support from NSERC, CRC, AITF, and NINT. Reference: Science 350, 798 (2015).

  18. Controlling interactions between highly magnetic atoms with Feshbach resonances.

    PubMed

    Kotochigova, Svetlana

    2014-09-01

    This paper reviews current experimental and theoretical progress in the study of dipolar quantum gases of ground and meta-stable atoms with a large magnetic moment. We emphasize the anisotropic nature of Feshbach resonances due to coupling to fast-rotating resonant molecular states in ultracold s-wave collisions between magnetic atoms in external magnetic fields. The dramatic differences in the distribution of resonances of magnetic (7)S3 chromium and magnetic lanthanide atoms with a submerged 4f shell and non-zero electron angular momentum is analyzed. We focus on dysprosium and erbium as important experimental advances have been recently made to cool and create quantum-degenerate gases for these atoms. Finally, we describe progress in locating resonances in collisions of meta-stable magnetic atoms in electronic P-states with ground-state atoms, where an interplay between collisional anisotropies and spin-orbit coupling exists.

  19. Wernicke’s Encephalopathy in a Patient with Nasopharyngeal Carcinoma: Magnetic Resonance Imaging Findings

    PubMed Central

    Law, Huong Ling; Tan, Suzet; Sedi, Rosleena

    2011-01-01

    We report a case of Wernicke’s encephalopathy in a patient with nasopharyngeal carcinoma with a 3-month history of poor oral intake related to nausea and vomiting due to chemotherapy. The patient later developed deep coma while receiving in-patient therapy. Magnetic resonance imaging of the brain revealed typical findings of Wernicke’s encephalopathy. The patient was treated with thiamine injections, which resulted in subsequent partial recovery of neurological function. This paper stresses the importance of magnetic resonance imaging for prompt diagnosis of Wernicke’s encephalopathy. PMID:22135604

  20. Detection of testicular torsion by magnetic resonance imaging in a rat model.

    PubMed

    Landa, H M; Gylys-Morin, V; Mattery, R F; Hajek, P; Krous, H F; Kaplan, G W; Packer, M G

    1988-11-01

    Testicular torsion is one of the most common pediatric urological emergencies. Incorrect or delayed diagnosis contributes significantly to morbidity. We previously have shown that magnetic resonance displays scrotal contents with great detail using hydrogen concentration weighted and T2 weighted images. Sprague-Dawley rats underwent either unilateral 720-degree testicular torsion or a sham procedure. Magnetic resonance images were obtained at intervals with a 3 or 5-inch surface coil. Scans after surgical torsion showed a characteristic spiral distortion of the fascial planes of the spermatic cord, not seen in the sham animals, as well as a decrease in testicular size with prolonged torsion.

  1. Rescaled Local Interaction Simulation Approach for Shear Wave Propagation Modelling in Magnetic Resonance Elastography

    PubMed Central

    Packo, P.; Staszewski, W. J.; Uhl, T.

    2016-01-01

    Properties of soft biological tissues are increasingly used in medical diagnosis to detect various abnormalities, for example, in liver fibrosis or breast tumors. It is well known that mechanical stiffness of human organs can be obtained from organ responses to shear stress waves through Magnetic Resonance Elastography. The Local Interaction Simulation Approach is proposed for effective modelling of shear wave propagation in soft tissues. The results are validated using experimental data from Magnetic Resonance Elastography. These results show the potential of the method for shear wave propagation modelling in soft tissues. The major advantage of the proposed approach is a significant reduction of computational effort. PMID:26884808

  2. Magnetic resonance techniques for investigation of multiple sclerosis

    NASA Astrophysics Data System (ADS)

    MacKay, Alex; Laule, Cornelia; Li, David K. B.; Meyers, Sandra M.; Russell-Schulz, Bretta; Vavasour, Irene M.

    2014-11-01

    Multiple sclerosis (MS) is a common neurological disease which can cause loss of vision and balance, muscle weakness, impaired speech, fatigue, cognitive dysfunction and even paralysis. The key pathological processes in MS are inflammation, edema, myelin loss, axonal loss and gliosis. Unfortunately, the cause of MS is still not understood and there is currently no cure. Magnetic resonance imaging (MRI) is an important clinical and research tool for MS. 'Conventional' MRI images of MS brain reveal bright lesions, or plaques, which demark regions of severe tissue damage. Conventional MRI has been extremely valuable for the diagnosis and management of people who have MS and also for the assessment of therapies designed to reduce inflammation and promote repair. While conventional MRI is clearly valuable, it lack pathological specificity and, in some cases, sensitivity to non-lesional pathology. Advanced MR techniques have been developed to provide information that is more sensitive and specific than what is available with clinical scanning. Diffusion tensor imaging and magnetization transfer provide a general but non-specific measure of the pathological state of brain tissue. MR spectroscopy provides concentrations of brain metabolites which can be related to specific pathologies. Myelin water imaging was designed to assess brain myelination and has proved useful for measuring myelin loss in MS. To combat MS, it is crucial that the pharmaceutical industry finds therapies which can reverse the neurodegenerative processes which occur in the disease. The challenge for magnetic resonance researchers is to design imaging techniques which can provide detailed pathological information relating to the mechanisms of MS therapies. This paper briefly describes the pathologies of MS and demonstrates how MS-associated pathologies can be followed using both conventional and advanced MR imaging protocols.

  3. Quantifying mixing using magnetic resonance imaging.

    PubMed

    Tozzi, Emilio J; McCarthy, Kathryn L; Bacca, Lori A; Hartt, William H; McCarthy, Michael J

    2012-01-25

    Mixing is a unit operation that combines two or more components into a homogeneous mixture. This work involves mixing two viscous liquid streams using an in-line static mixer. The mixer is a split-and-recombine design that employs shear and extensional flow to increase the interfacial contact between the components. A prototype split-and-recombine (SAR) mixer was constructed by aligning a series of thin laser-cut Poly (methyl methacrylate) (PMMA) plates held in place in a PVC pipe. Mixing in this device is illustrated in the photograph in Fig. 1. Red dye was added to a portion of the test fluid and used as the minor component being mixed into the major (undyed) component. At the inlet of the mixer, the injected layer of tracer fluid is split into two layers as it flows through the mixing section. On each subsequent mixing section, the number of horizontal layers is duplicated. Ultimately, the single stream of dye is uniformly dispersed throughout the cross section of the device. Using a non-Newtonian test fluid of 0.2% Carbopol and a doped tracer fluid of similar composition, mixing in the unit is visualized using magnetic resonance imaging (MRI). MRI is a very powerful experimental probe of molecular chemical and physical environment as well as sample structure on the length scales from microns to centimeters. This sensitivity has resulted in broad application of these techniques to characterize physical, chemical and/or biological properties of materials ranging from humans to foods to porous media (1, 2). The equipment and conditions used here are suitable for imaging liquids containing substantial amounts of NMR mobile (1)H such as ordinary water and organic liquids including oils. Traditionally MRI has utilized super conducting magnets which are not suitable for industrial environments and not portable within a laboratory (Fig. 2). Recent advances in magnet technology have permitted the construction of large volume industrially compatible magnets suitable for

  4. Planetary gearbox fault diagnosis using an adaptive stochastic resonance method

    NASA Astrophysics Data System (ADS)

    Lei, Yaguo; Han, Dong; Lin, Jing; He, Zhengjia

    2013-07-01

    Planetary gearboxes are widely used in aerospace, automotive and heavy industry applications due to their large transmission ratio, strong load-bearing capacity and high transmission efficiency. The tough operation conditions of heavy duty and intensive impact load may cause gear tooth damage such as fatigue crack and teeth missed etc. The challenging issues in fault diagnosis of planetary gearboxes include selection of sensitive measurement locations, investigation of vibration transmission paths and weak feature extraction. One of them is how to effectively discover the weak characteristics from noisy signals of faulty components in planetary gearboxes. To address the issue in fault diagnosis of planetary gearboxes, an adaptive stochastic resonance (ASR) method is proposed in this paper. The ASR method utilizes the optimization ability of ant colony algorithms and adaptively realizes the optimal stochastic resonance system matching input signals. Using the ASR method, the noise may be weakened and weak characteristics highlighted, and therefore the faults can be diagnosed accurately. A planetary gearbox test rig is established and experiments with sun gear faults including a chipped tooth and a missing tooth are conducted. And the vibration signals are collected under the loaded condition and various motor speeds. The proposed method is used to process the collected signals and the results of feature extraction and fault diagnosis demonstrate its effectiveness.

  5. Tuning Coler Magnetic Current Apparatus with Magneto-Acoustic Resonance

    NASA Astrophysics Data System (ADS)

    Ludwig, Thorsten

    An attempt was made to tune the Coler magnetic current apparatus with the magneto acoustic resonance of the magnetic rods. Measurements with a replica of the famous Coler "Magnetstromapparat" were conducted. In order to tune the acoustic, magnetic and electric resonance circuits of the Coler device the magneto-acoustic resonance was measured with a frequency scan through a function generator and a lock-in amplifier. The frequency generator was powering a driving coil, while the lock-in was connected to a pickup coil. Both coils were placed on a magnetic rod. Resonances were observed up to the 17th harmonic. The quality Q of the observed resonances was 270. To study the magneto-acoustic resonance in the time domain a pair of Permendur rods were employed. The magneto-acoustic resonances of the Permendur rods were observed with an oscilloscope. Spectra of the magneto acoustic resonance were measured for the Permendur rods and for a Coler replica magnet in the frequency range from 25 kHz to 380 kHz. The next step was to bring the resonances of the Permendur rods close together so that they overlap. The 10thharmonic was chosen because it was close to the 180 kHz that Hans Coler related to ferromagnetism. Further more magneto-acoustic coupling between the Permendur rods was studied. Finally the question was explored if Hans Coler converted vacuum fluctuations via magnetic and acoustic resonance into electricity. There is a strong connection between magnetism and quantum field zero point energy (ZPE). An outlook is given on next steps in the experiments to unveil the working mechanism of the Coler magnetic current apparatus.

  6. Magnetic resonance imaging of oscillating electrical currents

    PubMed Central

    Halpern-Manners, Nicholas W.; Bajaj, Vikram S.; Teisseyre, Thomas Z.; Pines, Alexander

    2010-01-01

    Functional MRI has become an important tool of researchers and clinicians who seek to understand patterns of neuronal activation that accompany sensory and cognitive processes. However, the interpretation of fMRI images rests on assumptions about the relationship between neuronal firing and hemodynamic response that are not firmly grounded in rigorous theory or experimental evidence. Further, the blood-oxygen-level-dependent effect, which correlates an MRI observable to neuronal firing, evolves over a period that is 2 orders of magnitude longer than the underlying processes that are thought to cause it. Here, we instead demonstrate experiments to directly image oscillating currents by MRI. The approach rests on a resonant interaction between an applied rf field and an oscillating magnetic field in the sample and, as such, permits quantitative, frequency-selective measurements of current density without spatial or temporal cancellation. We apply this method in a current loop phantom, mapping its magnetic field and achieving a detection sensitivity near the threshold required for the detection of neuronal currents. Because the contrast mechanism is under spectroscopic control, we are able to demonstrate how ramped and phase-modulated spin-lock radiation can enhance the sensitivity and robustness of the experiment. We further demonstrate the combination of these methods with remote detection, a technique in which the encoding and detection of an MRI experiment are separated by sample flow or translation. We illustrate that remotely detected MRI permits the measurement of currents in small volumes of flowing water with high sensitivity and spatial resolution. PMID:20421504

  7. Tolosa–Hunt Syndrome Demonstrated by Constructive Interference Steady State Magnetic Resonance Imaging

    PubMed Central

    Wani, Nisar A.; Jehangir, Majid; Lone, Parveen A.

    2017-01-01

    Purpose: To highlight the role of constructive interference steady state (CISS) magnetic resonance imaging (MRI) in the diagnosis of Tolosa-Hunt Syndrome (THS). Case Report: We describe a case of THS in a 55-year-old woman presenting with left painful opthalmoplegia that was diagnosed by CISS MRI. Patient responded to steroid treatment and the lesion resolved. Conclusion: Imaging with MRI can help in making the diagnosis of THS by demonstrating an enhancing soft tissue lesion in the cavernous sinus and orbital apex resolving with steroids. CISS MRI is a sensitive sequence for diagnosis and follow-up imaging in THS. PMID:28299013

  8. Magnetic resonance urography in evaluation of duplicated renal collecting systems.

    PubMed

    Adeb, Melkamu; Darge, Kassa; Dillman, Jonathan R; Carr, Michael; Epelman, Monica

    2013-11-01

    Duplex renal collecting systems are common congenital anomalies of the upper urinary tract. In most cases they are incidental findings and not associated with additional pathologies. They demonstrate, however, higher incidences of hydroureteronephrosis, ureteroceles, and ectopic ureters. The most comprehensive morphologic and functional evaluation of duplex systems can be achieved using magnetic resonance urography. Functional magnetic resonance urography allows better separation of the renal poles, thus more accurate calculation of the differential renal functions compared with renal scintigraphy. Magnetic resonance urography is the study of choice when upper urinary tract anatomy is complex or when functional evaluation is needed.

  9. Magnetic resonance imaging of fetal developmental anomalies.

    PubMed

    Girard, Nadine J

    2011-02-01

    Fetal developmental anomalies consist of central nervous system malformations, brain injury, and tumors. Overlap is often seen especially between malformation and injury because malformation may be genetically determined or related to external causative agent, whereas brain injury may be, on one hand, caused by malformation as with intracranial vascular malformation and, on another, can cause brain malformation when cerebral insult occurs during organogenesis and histogenesis. The goal of this review was not to describe by magnetic resonance imaging (MRI) all fetal developmental anomalies encountered in utero; it is most likely to focus on fetal brain anomalies that either are most commonly seen in fetal tertiary care facility or are extremely challenging for MRI. Consequently, the potential of advanced MR techniques such as proton MR spectroscopy and diffusion tensor imaging is also described especially when a challenge is highlighted. This review is therefore organized in subchapters as follows. The first section gives the place of MRI in prenatal development and cites the standard protocol and the advanced techniques. The rules of fetal brain MRI, the challenge and pitfalls, and the selection of MRI cases follow as 3 subchapters. Also, abnormalities are described as 3 separate subchapters entitled ventriculomegalies (hydrocephalus), malformations, and brain injury.

  10. Magnetic Resonance Elastography: Inversions in Bounded Media

    PubMed Central

    Kolipaka, Arunark; McGee, Kiaran P.; Manduca, Armando; Romano, Anthony J.; Glaser, Kevin J.; Araoz, Philip A.; Ehman, Richard L.

    2009-01-01

    Magnetic resonance elastography (MRE) is a noninvasive imaging technique capable of quantifying and spatially resolving the shear stiffness of soft tissues by visualization of synchronized mechanical wave displacement fields. However, MRE inversions generally assume that the measured tissue motion consists primarily of shear waves propagating in a uniform, infinite medium. This assumption is not valid in organs such as the heart, eye, bladder, skin, fascia, bone and spinal cord in which the shear wavelength approaches the geometric dimensions of the object. The aim of this study was to develop and test mathematical inversion algorithms capable of resolving shear stiffness from displacement maps of flexural waves propagating in bounded media such as beams, plates and spherical shells using geometry-specific equations of motion. MRE and finite element modeling (FEM) of beam, plate, and spherical shell phantoms of various geometries were performed. Mechanical testing of the phantoms agreed with the stiffness values obtained from FEM and MRE data and a linear correlation of r2 ≥ 0.99 was observed between the stiffness values obtained using MRE and FEM data. In conclusion, we have demonstrated new inversion methods for calculating shear stiffness that may be more appropriate for waves propagating in bounded media. PMID:19780146

  11. Vibration safety limits for magnetic resonance elastography.

    PubMed

    Ehman, E C; Rossman, P J; Kruse, S A; Sahakian, A V; Glaser, K J

    2008-02-21

    Magnetic resonance elastography (MRE) has been demonstrated to have potential as a clinical tool for assessing the stiffness of tissue in vivo. An essential step in MRE is the generation of acoustic mechanical waves within a tissue via a coupled mechanical driver. Motivated by an increasing volume of human imaging trials using MRE, the objectives of this study were to audit the vibration amplitude of exposure for our IRB-approved human MRE studies, to compare these values to a conservative regulatory standard for vibrational exposure and to evaluate the applicability and implications of this standard for MRE. MRE displacement data were examined from 29 MRE exams, including the liver, brain, kidney, breast and skeletal muscle. Vibrational acceleration limits from a European Union directive limiting occupational exposure to whole-body and extremity vibrations (EU 2002/44/EC) were adjusted for time and frequency of exposure, converted to maximum displacement values and compared to the measured in vivo displacements. The results indicate that the vibrational amplitudes used in MRE studies are below the EU whole-body vibration limit, and the EU guidelines represent a useful standard that could be readily accepted by Institutional Review Boards to define standards for vibrational exposures for MRE studies in humans.

  12. TOPICAL REVIEW: Endovascular interventional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Bartels, L. W.; Bakker, C. J. G.

    2003-07-01

    Minimally invasive interventional radiological procedures, such as balloon angioplasty, stent placement or coiling of aneurysms, play an increasingly important role in the treatment of patients suffering from vascular disease. The non-destructive nature of magnetic resonance imaging (MRI), its ability to combine the acquisition of high quality anatomical images and functional information, such as blood flow velocities, perfusion and diffusion, together with its inherent three dimensionality and tomographic imaging capacities, have been advocated as advantages of using the MRI technique for guidance of endovascular radiological interventions. Within this light, endovascular interventional MRI has emerged as an interesting and promising new branch of interventional radiology. In this review article, the authors will give an overview of the most important issues related to this field. In this context, we will focus on the prerequisites for endovascular interventional MRI to come to maturity. In particular, the various approaches for device tracking that were proposed will be discussed and categorized. Furthermore, dedicated MRI systems, safety and compatibility issues and promising applications that could become clinical practice in the future will be discussed.

  13. Cardiovascular magnetic resonance in pericardial diseases

    PubMed Central

    Bogaert, Jan; Francone, Marco

    2009-01-01

    The pericardium and pericardial diseases in particular have received, in contrast to other topics in the field of cardiology, relatively limited interest. Today, despite improved knowledge of pathophysiology of pericardial diseases and the availability of a wide spectrum of diagnostic tools, the diagnostic challenge remains. Not only the clinical presentation may be atypical, mimicking other cardiac, pulmonary or pleural diseases; in developed countries a shift for instance in the epidemiology of constrictive pericarditis has been noted. Accurate decision making is crucial taking into account the significant morbidity and mortality caused by complicated pericardial diseases, and the potential benefit of therapeutic interventions. Imaging herein has an important role, and cardiovascular magnetic resonance (CMR) is definitely one of the most versatile modalities to study the pericardium. It fuses excellent anatomic detail and tissue characterization with accurate evaluation of cardiac function and assessment of the haemodynamic consequences of pericardial constraint on cardiac filling. This review focuses on the current state of knowledge how CMR can be used to study the most common pericardial diseases. PMID:19413898

  14. Magnetic resonance imaging of skeletal muscle disease.

    PubMed

    Damon, Bruce M; Li, Ke; Bryant, Nathan D

    2016-01-01

    Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multifaceted pathology. The goals of this chapter are to describe and evaluate the use of quantitative magnetic resonance imaging (MRI) methods to characterize muscle pathology. The following criteria are used for this evaluation: objective measurement of continuously distributed variables; clear and well-understood relationship to the pathology of interest; sensitivity to improvement or worsening of clinical status; and the measurement properties of accuracy and precision. Two major classes of MRI methods meet all of these criteria: (1) MRI methods for measuring muscle contractile volume or cross-sectional area by combining structural MRI and quantitative fat-water MRI; and (2) an MRI method for characterizing the edema caused by inflammation, the measurement of the transverse relaxation time constant (T2). These methods are evaluated with respect to the four criteria listed above and examples from neuromuscular disorders are provided. Finally, these methods are summarized and synthesized and recommendations for additional quantitative MRI developments are made.

  15. Compression-sensitive magnetic resonance elastography

    NASA Astrophysics Data System (ADS)

    Hirsch, Sebastian; Beyer, Frauke; Guo, Jing; Papazoglou, Sebastian; Tzschaetzsch, Heiko; Braun, Juergen; Sack, Ingolf

    2013-08-01

    Magnetic resonance elastography (MRE) quantifies the shear modulus of biological tissue to detect disease. Complementary to the shear elastic properties of tissue, the compression modulus may be a clinically useful biomarker because it is sensitive to tissue pressure and poromechanical interactions. In this work, we analyze the capability of MRE to measure volumetric strain and the dynamic bulk modulus (P-wave modulus) at a harmonic drive frequency commonly used in shear-wave-based MRE. Gel phantoms with various densities were created by introducing CO2-filled cavities to establish a compressible effective medium. The dependence of the effective medium's bulk modulus on phantom density was investigated via static compression tests, which confirmed theoretical predictions. The P-wave modulus of three compressible phantoms was calculated from volumetric strain measured by 3D wave-field MRE at 50 Hz drive frequency. The results demonstrate the MRE-derived volumetric strain and P-wave modulus to be sensitive to the compression properties of effective media. Since the reconstruction of the P-wave modulus requires third-order derivatives, noise remains critical, and P-wave moduli are systematically underestimated. Focusing on relative changes in the effective bulk modulus of tissue, compression-sensitive MRE may be useful for the noninvasive detection of diseases involving pathological pressure alterations such as hepatic hypertension or hydrocephalus.

  16. Vibration safety limits for magnetic resonance elastography

    NASA Astrophysics Data System (ADS)

    Ehman, E. C.; Rossman, P. J.; Kruse, S. A.; Sahakian, A. V.; Glaser, K. J.

    2008-02-01

    Magnetic resonance elastography (MRE) has been demonstrated to have potential as a clinical tool for assessing the stiffness of tissue in vivo. An essential step in MRE is the generation of acoustic mechanical waves within a tissue via a coupled mechanical driver. Motivated by an increasing volume of human imaging trials using MRE, the objectives of this study were to audit the vibration amplitude of exposure for our IRB-approved human MRE studies, to compare these values to a conservative regulatory standard for vibrational exposure and to evaluate the applicability and implications of this standard for MRE. MRE displacement data were examined from 29 MRE exams, including the liver, brain, kidney, breast and skeletal muscle. Vibrational acceleration limits from a European Union directive limiting occupational exposure to whole-body and extremity vibrations (EU 2002/44/EC) were adjusted for time and frequency of exposure, converted to maximum displacement values and compared to the measured in vivo displacements. The results indicate that the vibrational amplitudes used in MRE studies are below the EU whole-body vibration limit, and the EU guidelines represent a useful standard that could be readily accepted by Institutional Review Boards to define standards for vibrational exposures for MRE studies in humans.

  17. Segmentation of neuroanatomy in magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Simmons, Andrew; Arridge, Simon R.; Barker, G. J.; Tofts, Paul S.

    1992-06-01

    Segmentation in neurological magnetic resonance imaging (MRI) is necessary for feature extraction, volume measurement and for the three-dimensional display of neuroanatomy. Automated and semi-automated methods offer considerable advantages over manual methods because of their lack of subjectivity, their data reduction capabilities, and the time savings they give. We have used dual echo multi-slice spin-echo data sets which take advantage of the intrinsically multispectral nature of MRI. As a pre-processing step, a rf non-uniformity correction is applied and if the data is noisy the images are smoothed using a non-isotropic blurring method. Edge-based processing is used to identify the skin (the major outer contour) and the eyes. Edge-focusing has been used to significantly simplify edge images and thus allow simple postprocessing to pick out the brain contour in each slice of the data set. Edge- focusing is a technique which locates significant edges using a high degree of smoothing at a coarse level and tracks these edges to a fine level where the edges can be determined with high positional accuracy. Both 2-D and 3-D edge-detection methods have been compared. Once isolated, the brain is further processed to identify CSF, and, depending upon the MR pulse sequence used, the brain itself may be sub-divided into gray matter and white matter using semi-automatic contrast enhancement and clustering methods.

  18. Magnetic resonance imaging of the normal placenta.

    PubMed

    Blaicher, Wibke; Brugger, Peter C; Mittermayer, Christoph; Schwindt, Jens; Deutinger, Josef; Bernaschek, Gerhard; Prayer, Daniela

    2006-02-01

    The goal of this study was to provide a representative description of the normal placenta with contrast medium-free magnetic resonance imaging (MRI) in order to determine a standard of reference. One hundred consecutive singleton pregnancies were investigated by MRI without application of a contrast medium. The mean gestational age (GA) at the time of investigation was 29.5 weeks (range 19-40). Patients with suspected utero-placental insufficiency (UPI) or placental anomalies were excluded. Signal intensities were assessed and correlated with the respective GA. Antenatal MRI without contrast medium was able to depict placental status and morphological changes during gestation. A regular homogeneous structure was found in weeks 19-23. Subsequently, sporadic, slightly marked lobules appeared, which increased in number and markedness with ongoing gestation. Stratification of the lobules was observed after 36 weeks. The ratio of placental and amniotic fluid signal intensities decreased significantly with higher GA and with placental grading. MRI is well suited as an imaging method for the placenta. Our data may be used as a reference in the assessment of the placenta on MRI, and may have further clinical impact with respect to the determination of UPI.

  19. Adaptive fuzzy segmentation of magnetic resonance images.

    PubMed

    Pham, D L; Prince, J L

    1999-09-01

    An algorithm is presented for the fuzzy segmentation of two-dimensional (2-D) and three-dimensional (3-D) multispectral magnetic resonance (MR) images that have been corrupted by intensity inhomogeneities, also known as shading artifacts. The algorithm is an extension of the 2-D adaptive fuzzy C-means algorithm (2-D AFCM) presented in previous work by the authors. This algorithm models the intensity inhomogeneities as a gain field that causes image intensities to smoothly and slowly vary through the image space. It iteratively adapts to the intensity inhomogeneities and is completely automated. In this paper, we fully generalize 2-D AFCM to three-dimensional (3-D) multispectral images. Because of the potential size of 3-D image data, we also describe a new faster multigrid-based algorithm for its implementation. We show, using simulated MR data, that 3-D AFCM yields lower error rates than both the standard fuzzy C-means (FCM) algorithm and two other competing methods, when segmenting corrupted images. Its efficacy is further demonstrated using real 3-D scalar and multispectral MR brain images.

  20. Magnetic resonance imaging of the kidneys

    SciTech Connect

    Leung, A.W.L.; Bydder, G.M.; Steinter, R.E.; Bryant, D.J.; Young, I.R.

    1984-12-01

    A study of the magnetic resonance imaging (MRI) appearance of the kidneys in six normal volunteers and 52 patients is reported. Corticomedullary differentiation was seen with the inversion-recovery (IR 1400/400) sequence in the normal volunteers and in patients with functioning transplanted kidneys and acute tubular necrosis. Partial or total loss of corticomedullary differentiation was seen in glomerulonephritis, acute and chronic renal failure, renal artery stenosis, and transplant rejection. The T1 of the kidneys was increased in glomerulonephritis with neuphrotic syndrome, but the T1 was within the normal range for renal medulla in glomerulonephritis without nephrotic syndrome, renal artery stenosis, and chronic renal failure. A large staghorn calculus was demonstrated with MRI, but small calculi were not seen. Fluid within the hydonephrosis, simple renal cysts, and polycystic kidneys displayed very low signal intensity and long T1 values. Tumors displayed varied appearances. Hypernephromas were shown to be hypo- or hyperintense with the renal medulla on the IR 1400/400 sequence. After intravenous injection of gadolinium-DTPA, there was marked decrease in the tumor T1.

  1. Magnetic Resonance Imaging of Cartilage Repair

    PubMed Central

    Trattnig, Siegfried; Winalski, Carl S.; Marlovits, Stephan; Jurvelin, Jukka S.; Welsch, Goetz H.; Potter, Hollis G.

    2011-01-01

    Articular cartilage lesions are a common pathology of the knee joint, and many patients may benefit from cartilage repair surgeries that offer the chance to avoid the development of osteoarthritis or delay its progression. Cartilage repair surgery, no matter the technique, requires a noninvasive, standardized, and high-quality longitudinal method to assess the structure of the repair tissue. This goal is best fulfilled by magnetic resonance imaging (MRI). The present article provides an overview of the current state of the art of MRI of cartilage repair. In the first 2 sections, preclinical and clinical MRI of cartilage repair tissue are described with a focus on morphological depiction of cartilage and the use of functional (biochemical) MR methodologies for the visualization of the ultrastructure of cartilage repair. In the third section, a short overview is provided on the regulatory issues of the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) regarding MR follow-up studies of patients after cartilage repair surgeries. PMID:26069565

  2. Open Circuit Resonant Sensors for Composite Damage Detection and Diagnosis

    NASA Technical Reports Server (NTRS)

    Mielnik, John J., Jr.

    2011-01-01

    Under the Integrated Vehicle Health Management (IVHM) program work was begun to investigate the feasibility of sensor systems for detecting and diagnosing damage to aircraft composite structures and materials. Specific interest for this study was in damage initiated by environmental storm hazards and the direct effect of lightning strikes on the material structures of a composite aircraft in flight. A series of open circuit resonant sensors was designed, fabricated, characterized, and determined to be a potentially viable means for damage detection and diagnosis of composite materials. The results of this research and development effort are documented in this report.

  3. Sublingual Epidermoid Cyst Presenting with Distinctive Magnetic Resonance Imaging Findings

    PubMed Central

    Yoshida, Naohiro; Kodama, Kozue; Iino, Yukiko

    2014-01-01

    A case of sublingual epidermoid cyst presenting distinctive magnetic resonance imaging (MRI) findings is described. A 39-year-old man presented to our hospital with a three months progressive left submandibular swelling, difficulty moving his tongue, and snoring. Preoperative evaluation with MRI and fine needle aspiration cytology (FNAC) revealed that the heterogeneous cystic lesion contained the squamous cells, which is compatible with ectodermal tissue. The mass was located above the mylohyoid muscle and spread to the pharyngeal space. By considering the size, infection history, patient age, and location, the cyst was completely resected under general anesthesia via cervical approach without any complication. Histopathologically, the cyst wall was lined by stratified squamous epithelium with no skin appendage, suggesting an epidermoid cyst. Ultrasound (US), MRI and FNAC were very useful of the preoperative diagnosis for oral and sublingual lesion. The postoperative course was uneventful and without recurrence after 24 months. This case showed that epidermoid cysts formed the rarely heterogeneous cystic tumor and it underlined usefulness of preoperative diagnosis, such as US, MRI and FNAC for oral and sublingual tumor. PMID:25332766

  4. Cavity resonator coil for high field magnetic resonance imaging.

    PubMed

    Solis, S E; Tomasi, D; Rodriguez, A O

    2007-01-01

    A variant coil of the high frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. This coil design is similar to the popular birdcage coil but it has the advantage that it can be easily built following the physical principles of the cavity resonators [1]. The equivalent circuit approach was used to compute the resonant frequency of this coil design, and compared the results with those frequency values obtained with theory. A transceiver coil composed of 4 cavities with a rod length of 4.5 cm, and a resonant frequency of 170.29 MHz was built. Phantom images were then acquired to test its viability using standard imaging sequences. The theory facilitates its development for high frequency MRI applications of animal models.

  5. Magnetic resonance force microscopy with a permanent magnet on the cantilever

    SciTech Connect

    Zhang, Z.; Hammel, P.C.

    1997-02-01

    The magnetic resonance force microscope (MRFM) is a microscopic 3-D imaging instrument based on a recent proposal to detect magnetic resonance signals mechanically using a micro-mechanical resonator. MRFM has been successfully demonstrated in various magnetic resonance experiments including electron spin resonance, ferromagnetic resonances and nuclear magnetic resonance. In order to apply this ultra-high, 3-D spatial resolution technique to samples of arbitrary size and shape, the magnetic particle which generates the field gradient {del}{bold B}, (and, therefore, the force {bold F = (m {center_dot} {del}B)} between itself and the spin magnetization {bold m} of the sample) will need to be mounted on the mechanical resonator. Up to the present, all experiments have been performed with the sample mounted on the resonator. This is done, in part, to avoid the spurious response of the mechanical resonator which is generated by the variation of the magnetization of the magnetic particle as the external field is varied.

  6. Cardiac magnetic resonance imaging of a patient with an magnetic resonance imaging conditional permanent pacemaker

    PubMed Central

    Hogarth, Andrew J.; Artis, Nigel J.; Sivananthan, U. Mohan; Pepper, Chris B.

    2011-01-01

    Cardiac magnetic resonance imaging (MRI) is increasingly used as the optimum modality for cardiac imaging. An aging population and rising numbers of patients with permanent pacemakers means many such individuals may require cardiac MRI scanning in the future. Whilst the presence of a permanent pacemaker is historically regarded as a contra-indication to MRI scanning, pacemaker systems have been developed to limit any associated risks. No reports have been published regarding the use of such devices with cardiac MRI in a clinical setting. We present the safe, successful cardiac MRI scan of a patient with an MRI-conditional permanent pacing system. PMID:22355486

  7. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    PubMed

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-04-07

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed.

  8. Magnetic resonance in ferromagnetic films, multilayers and nanoparticle composites

    NASA Astrophysics Data System (ADS)

    Noginova, Natalia; Bates, Brittany; Greene, Nicole

    2014-03-01

    Incorporation of magnetic materials into metamaterial systems provides an opportunity to tune microwave permeability with external magnetic field. We studied magnetically dependent microwave properties of polymer composites with iron oxide nanoparticles, ferromagnetic films and ferromagnetic/dielectric multilayers. We show that the permeability of such systems can be magnetically tuned from positive to negative values in the range of ferromagnetic resonance, strongly affecting wave propagation. Strong changes in mu-metal permeability in low field range provides an additional possibility of tuning.

  9. Advances in Magnetic Resonance Imaging of the Skull Base

    PubMed Central

    Kirsch, Claudia F.E.

    2014-01-01

    Introduction Over the past 20 years, magnetic resonance imaging (MRI) has advanced due to new techniques involving increased magnetic field strength and developments in coils and pulse sequences. These advances allow increased opportunity to delineate the complex skull base anatomy and may guide the diagnosis and treatment of the myriad of pathologies that can affect the skull base. Objectives The objective of this article is to provide a brief background of the development of MRI and illustrate advances in skull base imaging, including techniques that allow improved conspicuity, characterization, and correlative physiologic assessment of skull base pathologies. Data Synthesis Specific radiographic illustrations of increased skull base conspicuity including the lower cranial nerves, vessels, foramina, cerebrospinal fluid (CSF) leaks, and effacement of endolymph are provided. In addition, MRIs demonstrating characterization of skull base lesions, such as recurrent cholesteatoma versus granulation tissue or abscess versus tumor, are also provided as well as correlative clinical findings in CSF flow studies in a patient pre- and post-suboccipital decompression for a Chiari I malformation. Conclusions This article illustrates MRI radiographic advances over the past 20 years, which have improved clinicians' ability to diagnose, define, and hopefully improve the treatment and outcomes of patients with underlying skull base pathologies. PMID:25992137

  10. High accuracy and contrast resolution in ultra-low field magnetic resonance imaging.

    PubMed

    Agartz, I; Sääf, J; Wahlund, B; Wahlund, L O; Wetterberg, L

    1986-01-01

    Magnetic resonance imaging (MRI) at low magnetic field strengths is known to have a comparatively high contrast resolution. Current techniques increasing the signal to noise ratio 3 to 4 times allow for an improvement in the spatial resolution still maintaining the high contrast resolution. The contributing features to this advancement are improvements in software, development of new radiofrequency coils and image processing computors. The subsequent improvement in image evaluation and the access to added information make for a high accuracy in clinical diagnosis and research. The present potential of imaging at ultra-low (0.02 tesla) magnetic field strengths is illustrated with examples from clinical practice and research.

  11. Beam induced electron cloud resonances in dipole magnetic fields

    NASA Astrophysics Data System (ADS)

    Calvey, J. R.; Hartung, W.; Makita, J.; Venturini, M.

    2016-07-01

    The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring. These measurements are supported by both analytical models and computer simulations.

  12. Magnetism of gold nanorods probed using electron spin resonance

    NASA Astrophysics Data System (ADS)

    Inagaki, Y.; Yonemura, H.; Sakai, N.; Makihara, Y.; Kawae, T.; Yamada, S.

    2016-08-01

    Electron spin resonance (ESR) spectroscopy has been performed for gold nanorods (AuNRs) of four different sizes covered with a diamagnetic stabilizing component, cetyltrimethylammonium bromide. ESR signals were detected in AuNRs except the largest one. Two smallest AuNRs showed an abrupt change in the temperature dependence of resonance field and line width at around 60 K, indicating ferromagnetic phase transition. In medium-size AuNRs, the resonance with a large shift was observed below 100 K. The resonance field shifts at the lowest temperature exhibit systematic variation with the system size, which is explained by considering magnetic anisotropy for the ferromagnetic resonance.

  13. Element Selective X-ray Detected Magnetic Resonance

    SciTech Connect

    Goulon, J.; Rogalev, A.; Wilhelm, F.; Jaouen, N.; Goulon-Ginet, C.; Goujon, G.; Youssef, J. Ben; Indenbom, M. V.

    2007-01-19

    Element selective X-ray Detected Magnetic Resonance (XDMR) was measured on exciting the Fe K-edge in a high quality YIG thin film. Resonant pumping at high microwave power was achieved in the nonlinear foldover regime and X-ray Magnetic Circular Dichroism (XMCD) was used to probe the time-invariant change of the magnetization {delta}Mz due to the precession of orbital magnetization densities of states (DOS) at the Fe sites. This challenging experiment required us to design a specific instrumentation which is briefly described.

  14. Broadband electrically detected magnetic resonance using adiabatic pulses

    NASA Astrophysics Data System (ADS)

    Hrubesch, F. M.; Braunbeck, G.; Voss, A.; Stutzmann, M.; Brandt, M. S.

    2015-05-01

    We present a broadband microwave setup for electrically detected magnetic resonance (EDMR) based on microwave antennae with the ability to apply arbitrarily shaped pulses for the excitation of electron spin resonance (ESR) and nuclear magnetic resonance (NMR) of spin ensembles. This setup uses non-resonant stripline structures for on-chip microwave delivery and is demonstrated to work in the frequency range from 4 MHz to 18 GHz. π pulse times of 50 ns and 70 μs for ESR and NMR transitions, respectively, are achieved with as little as 100 mW of microwave or radiofrequency power. The use of adiabatic pulses fully compensates for the microwave magnetic field inhomogeneity of the stripline antennae, as demonstrated with the help of BIR4 unitary rotation pulses driving the ESR transition of neutral phosphorus donors in silicon and the NMR transitions of ionized phosphorus donors as detected by electron nuclear double resonance (ENDOR).

  15. Broadband electrically detected magnetic resonance using adiabatic pulses.

    PubMed

    Hrubesch, F M; Braunbeck, G; Voss, A; Stutzmann, M; Brandt, M S

    2015-05-01

    We present a broadband microwave setup for electrically detected magnetic resonance (EDMR) based on microwave antennae with the ability to apply arbitrarily shaped pulses for the excitation of electron spin resonance (ESR) and nuclear magnetic resonance (NMR) of spin ensembles. This setup uses non-resonant stripline structures for on-chip microwave delivery and is demonstrated to work in the frequency range from 4 MHz to 18 GHz. π pulse times of 50 ns and 70 μs for ESR and NMR transitions, respectively, are achieved with as little as 100 mW of microwave or radiofrequency power. The use of adiabatic pulses fully compensates for the microwave magnetic field inhomogeneity of the stripline antennae, as demonstrated with the help of BIR4 unitary rotation pulses driving the ESR transition of neutral phosphorus donors in silicon and the NMR transitions of ionized phosphorus donors as detected by electron nuclear double resonance (ENDOR).

  16. Magnetic Nanoparticles for Cancer Diagnosis and Therapy

    PubMed Central

    Yigit, Mehmet V.; Moore, Anna

    2013-01-01

    Nanotechnology is evolving as a new field that has a potentially high research and clinical impact. Medicine, in particular, could benefit from nanotechnology, due to emerging applications for noninvasive imaging and therapy. One important nanotechnological platform that has shown promise includes the so-called iron oxide nanoparticles. With specific relevance to cancer therapy, iron oxide nanoparticle-based therapy represents an important alternative to conventional chemotherapy, radiation, or surgery. Iron oxide nanoparticles are usually composed of three main components: an iron core, a polymer coating, and functional moieties. The biodegradable iron core can be designed to be superparamagnetic. This is particularly important, if the nanoparticles are to be used as a contrast agent for noninvasive magnetic resonance imaging (MRI). Surrounding the iron core is generally a polymer coating, which not only serves as a protective layer but also is a very important component for transforming nanoparticles into biomedical nanotools for in vivo applications. Finally, different moieties attached to the coating serve as targeting macromolecules, therapeutics payloads, or additional imaging tags. Despite the development of several nanoparticles for biomedical applications, we believe that iron oxide nanoparticles are still the most promising platform that can transform nanotechnology into a conventional medical discipline. PMID:22274558

  17. Nuclear Magnetic Double Resonance Using Weak Perturbing RF Fields

    ERIC Educational Resources Information Center

    Reynolds, G. Fredric

    1977-01-01

    Describes a nuclear magnetic resonance experimental example of spin tickling; also discusses a direct approach for verifying the relative signs of coupling constants in three-spin cyclopropyl systems. (SL)

  18. Magnetic resonance imaging of sports injuries of the ankle.

    PubMed

    Morrison, William B

    2003-04-01

    Basic sports-related injuries of the ankle include ligament tear, tendon degeneration and tear, bone bruise, fracture, impingement, osteochondral defect, and plantar fasciitis. This article discusses the magnetic resonance imaging appearance of these injuries.

  19. Normal perinatal and paediatric postmortem magnetic resonance imaging appearances.

    PubMed

    Arthurs, Owen J; Barber, Joy L; Taylor, Andrew M; Sebire, Neil J

    2015-04-01

    As postmortem imaging becomes more widely used following perinatal and paediatric deaths, the correct interpretation of images becomes imperative, particularly given the increased use of postmortem magnetic resonance imaging. Many pathological processes may have similar appearances in life and following death. A thorough knowledge of normal postmortem changes is therefore required within postmortem magnetic resonance imaging to ensure that these are not mistakenly interpreted as significant pathology. Similarly, some changes that are interpreted as pathological if they occur during life may be artefacts on postmortem magnetic resonance imaging that are of limited significance. This review serves to illustrate briefly those postmortem magnetic resonance imaging changes as part of the normal changes after death in fetuses and children, and highlight imaging findings that may confuse or mislead an observer to identifying pathology where none is present.

  20. Nuclear magnetic resonance data of C9H20OSi

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  1. Nuclear magnetic resonance data of C8H18OSi

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  2. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOEpatents

    Engelstad, Barry L.; Raymond, Kenneth N.; Huberty, John P.; White, David L.

    1991-01-01

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided.

  3. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOEpatents

    Engelstad, B.L.; Raymond, K.N.; Huberty, J.P.; White, D.L.

    1991-04-23

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided. No Drawings

  4. Nuclear magnetic resonance data of C10H15

    NASA Astrophysics Data System (ADS)

    Kalinowski, H.-O.; Kumar, M.; Gupta, V.; Gupta, R.

    This document is part of Part 1 `Aliphatic Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  5. Magnetic Resonance Fiber Tracking in a Neonate with Hemimegalencephaly

    PubMed Central

    Re, Thomas J; Scarciolla, Laura; Takahashi, Emi; Specchio, Nicola; Bernardi, Bruno; Longo, Daniela

    2015-01-01

    A magnetic resonance diffusion fiber tracking study in neonate diagnosed with left hemisphere hemimegalencephaly is presented. Despite diffuse morphologic deformities identified in conventional imaging, all major pathways were identifiable bilaterally with minor aberrations in vicinity of morphologic lesions. PMID:25655045

  6. Nuclear magnetic resonance in environmental engineering: principles and applications.

    PubMed

    Lens, P N; Hemminga, M A

    1998-01-01

    This paper gives an introduction to nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) in relation to applications in the field of environmental science and engineering. The underlying principles of high resolution solution and solid state NMR, relaxation time measurements and imaging are presented. Then, the use of NMR is illustrated and reviewed in studies of biodegradation and biotransformation of soluble and solid organic matter, removal of nutrients and xenobiotics, fate of heavy metal ions, and transport processes in bioreactor systems.

  7. Magnetic resonance imaging of experimental testicular torsion.

    PubMed

    Kaipia, A; Ryymin, P; Mäkelä, E; Aaltonen, M; Kähärä, V; Kangasniemi, M

    2005-12-01

    We investigated the feasibility of contrast enhanced (CE)-dynamic magnetic resonance imaging (MRI) for the detection of testicular torsion induced hypoperfusion in an experimental rat model. Adult Sprague-Dawley rats were subjected to unilateral testicular torsion of 360 or 720 degrees. After 1 h, the tail veins of the anaesthetized rats were cannulated and T2 -, diffusion-weighted and T1-weighted CE-dynamic MRI were subsequently performed by a 1.5 T MRI scanner. On apparent diffusion coefficient (ADC) images, the region of interest values of the ischaemic and control testes was compared. From CE-dynamic MR images, the maximal slopes of contrast enhancement were calculated and compared. In testicular torsion of 360 degrees, the maximal slope of contrast enhancement was 0.072%/s vs. 0.47%/s in the contralateral control testis (p < 0.001). A torsion of 720 degrees diminished the slope of contrast enhancement to 0.046%/s vs. 0.37%/s in the contralateral testis (p < 0.001). Diminished blood flow during torsion also followed in decreased ADC values in both 360 degrees (12.4% decrease; p < 0.05) and 720 degrees (10.8% decrease; p < 0.001) of torsion. Torsion of the testis causes ipsilateral hypoperfusion and decreased gadolinium uptake in a rat model that can be easily detected and quantified by CE-dynamic MRI. In diffusion-weighted MRI images, acute hypoperfusion results in a slight decrease of ADC values. Our results suggest that CE-dynamic MRI in combination with diffusion-weighted MRI can be used to detect compromised blood flow due to acute testicular torsion.

  8. Identification of cortex in magnetic resonance images

    NASA Astrophysics Data System (ADS)

    VanMeter, John W.; Sandon, Peter A.

    1992-06-01

    The overall goal of the work described here is to make available to the neurosurgeon in the operating room an on-line, three-dimensional, anatomically labeled model of the patient brain, based on pre-operative magnetic resonance (MR) images. A stereotactic operating microscope is currently in experimental use, which allows structures that have been manually identified in MR images to be made available on-line. We have been working to enhance this system by combining image processing techniques applied to the MR data with an anatomically labeled 3-D brain model developed from the Talairach and Tournoux atlas. Here we describe the process of identifying cerebral cortex in the patient MR images. MR images of brain tissue are reasonably well described by material mixture models, which identify each pixel as corresponding to one of a small number of materials, or as being a composite of two materials. Our classification algorithm consists of three steps. First, we apply hierarchical, adaptive grayscale adjustments to correct for nonlinearities in the MR sensor. The goal of this preprocessing step, based on the material mixture model, is to make the grayscale distribution of each tissue type constant across the entire image. Next, we perform an initial classification of all tissue types according to gray level. We have used a sum of Gaussian's approximation of the histogram to perform this classification. Finally, we identify pixels corresponding to cortex, by taking into account the spatial patterns characteristic of this tissue. For this purpose, we use a set of matched filters to identify image locations having the appropriate configuration of gray matter (cortex), cerebrospinal fluid and white matter, as determined by the previous classification step.

  9. Magnetic resonance imaging of thyroid nodules

    SciTech Connect

    Kroop, S.A.; Margouleff, D.; Stein, H.L.; Zanzi, I.; Susin, M.; Goldman, M.A.

    1985-05-01

    The capacity of Magnetic Resonance (MR) imaging to characterize the nature of palpable thyroid nodules was prospectively evaluated in 9 patients. Seven nodules were nonfunctioning and 2 showed function on radio-iodine Nuclear Medicine (NM) scans. Each patient underwent high-resolution real time ultrasound (US) examination followed by MR imaging with a 0.6 Tesla superconducting whole body coil utilizing T/sub 1/ and T/sub 2/ weighted inversion recovery and spin-echo pulse sequences in coronal, transverse and sagittal planes. All NM, US and MR studies were evaluated independently by each of two physicians. Diagnoses were established by surgical pathology (n=7) or by radiologic and clinical correlation (n=2). There were 3 cases of solitary adenoma, 4 cases of adenomatous goiter, 1 case of papillary carcinoma and 1 case of epidermoid carcinoma. Lesions demonstrated variable signal intensity on T/sub 1/ weighted images. All lesions demonstrated nonspecific increased signal intensity on T/sub 2/ weighted images. One malignancy was correctly diagnosed by the identification of adjacent cervical lymph nodes of increased signal intensity and another by demonstration of tracheal invasion on MR images, both not visible by other imaging modalities. Regions of hemorrhage and cystic degeneration as well as additional non-palpable thyroid nodules could be detected on MR images. Vascular displacement, tracheal compression and deviation, and substernal thyroid extension were also well demonstrated. The findings suggest that qualitative assessment of MR signal intensity alone cannot reliably differentiate benign from malignant thyroid lesions, but that MR images can provide other useful information to aid in this differentiation.

  10. Recent advances in cardiac magnetic resonance

    PubMed Central

    Greulich, Simon; Arai, Andrew E.; Sechtem, Udo; Mahrholdt, Heiko

    2016-01-01

    Cardiac magnetic resonance (CMR) is a non-invasive imaging modality that has rapidly emerged during the last few years and has become a valuable, well-established clinical tool. Beside the evaluation of anatomy and function, CMR has its strengths in providing detailed non-invasive myocardial tissue characterization, for which it is considered the current diagnostic gold standard. Late gadolinium enhancement (LGE), with its capability to detect necrosis and to separate ischemic from non-ischemic cardiomyopathies by distinct LGE patterns, offers unique clinical possibilities. The presence of LGE has also proven to be a good predictor of an adverse outcome in various studies. T2-weighted (T2w) images, which are supposed to identify areas of edema and inflammation, are another CMR approach to tissue characterization. However, T2w images have not held their promise owing to several technical limitations and potential physiological concerns. Newer mapping techniques may overcome some of these limitations: they assess quantitatively myocardial tissue properties in absolute terms and show promising results in studies for characterization of diffuse fibrosis (T1 mapping) and/or inflammatory processes (T2 mapping). However, these techniques are still research tools and are not part of the clinical routine yet. T2* CMR has had significant impact in the management of thalassemia because it is possible to image the amount of iron in the heart and the liver, improving both diagnostic imaging and the management of patients with thalassemia. CMR findings frequently have clinical impact on further patient management, and CMR seems to be cost effective in the clinical routine. PMID:27635240

  11. Magnetic Resonance Imaging of Normal Pressure Hydrocephalus.

    PubMed

    Bradley, William G

    2016-04-01

    Normal pressure hydrocephalus (NPH) is a syndrome found in the elderly, which is characterized by ventriculomegaly and deep white matter ischemia (DWMI) on magnetic resonance imaging (MRI) and the clinical triad of gait disturbance, dementia, and urinary incontinence. NPH has been estimated to account for up to 10% of cases of dementia and is significant because it is treatable by ventriculoperitoneal shunting. Patients with a known cause of chronic communicating hydrocephalus, that is, meningitis or hemorrhage, tend to respond better than patients with the so-called "idiopathic" form, most likely because of poor selection criteria in the past. Good response to shunting has been associated with hyperdynamic cerebrospinal fluid (CSF) flow through the aqueduct. In the early days of MRI, patients with a large CSF flow void extending from the foramen of Monro through the aqueduct to the fourth ventricle had an excellent chance of responding to ventriculoperitoneal shunting (P < 0.003). Today, we use phase-contrast MRI to measure the volume of CSF flowing through the aqueduct in either direction over a cardiac cycle. When this aqueductal CSF stroke volume is sufficiently elevated, there is an excellent chance of shunt responsiveness (100% positive predictive value in 1 study). Idiopathic NPH appears to be a "two-hit" disease-benign external hydrocephalus (BEH) in infancy followed by DWMI in late adulthood. As BEH occurs when the sutures are still open, these infants present with large heads, a finding also noted in patients with NPH. Although BEH has been attributed to immature arachnoidal granulations with decreased CSF resorptive capacity, this now appears to be permanent and may lead to a parallel pathway for CSF resorption via the extracellular space of the brain. With DWMI, the myelin lipid is lost, exposing the polar water molecules to myelin protein, increasing resistance to CSF outflow and leading to backing up of CSF and hydrocephalus.

  12. Single Molecule Magnetic Force Detection with a Carbon Nanotube Resonator

    NASA Astrophysics Data System (ADS)

    Willick, Kyle; Walker, Sean; Baugh, Jonathan

    2015-03-01

    Single molecule magnets (SMMs) sit at the boundary between macroscopic magnetic behaviour and quantum phenomena. Detecting the magnetic moment of an individual SMM would allow exploration of this boundary, and could enable technological applications based on SMMs such as quantum information processing. Detection of these magnetic moments remains an experimental challenge, particularly at the time scales of relaxation and decoherence. We present a technique for sensitive magnetic force detection that should permit such measurements. A suspended carbon nanotube (CNT) mechanical resonator is combined with a magnetic field gradient generated by a ferromagnetic gate electrode, which couples the magnetic moment of a nanomagnet to the resonant motion of the CNT. Numerical calculations of the mechanical resonance show that resonant frequency shifts on the order of a few kHz arise due to single Bohr magneton changes in magnetic moment. A signal-to-noise analysis based on thermomechanical noise shows that magnetic switching at the level of a Bohr magneton can be measured in a single shot on timescales as short as 10 μs. This sensitivity should enable studies of the spin dynamics of an isolated SMM, within the spin relaxation timescales for many available SMMs. Supported by NSERC.

  13. Prostate Cancer: The Role of Multiparametric Magnetic Resonance Imaging.

    PubMed

    Dias, João Lopes; Pina, João Magalhães; João, Raquel; Fialho, Joana; Carmo, Sandra; Leal, Cecília; Bilhim, Tiago; Marques, Rui Mateus; Pinheiro, Luís Campos

    2015-01-01

    Multiparametric magnetic resonance imaging has been increasingly used for detection, localization and staging of prostate cancer over the last years. It combines high-resolution T2 weighted-imaging and at least two functional techniques, which include dynamic contrast-enhanced magnetic resonance imaging, diffusion-weighted imaging, and magnetic resonance imaging spectroscopy. Although the combined use of a pelvic phased-array and an endorectal coil is considered the state-of-the-art for magnetic resonance imaging evaluation of prostate cancer, endorectal coil is only absolute mandatory for magnetic resonance imaging spectroscopy at 1.5 T. Sensitivity and specificity levels in cancer detection and localization have been improving with functional technique implementation, compared to T2 weighted-imaging alone. It has been particularly useful to evaluate patients with abnormal PSA and negative biopsy. Moreover, the information added by the functional techniques may correlate to cancer aggressiveness and therefore be useful to select patients for focal radiotherapy, prostate sparing surgery, focal ablative therapy and active surveillance. However, more studies are needed to compare the functional techniques and understand the advantages and disadvantages of each one. This article reviews the basic principles of prostatic mp-magnetic resonance imaging, emphasizing its role on detection, staging and active surveillance of prostate cancer.

  14. Left atrial metastases of poorly differentiated thyroid carcinoma diagnosed by echocardiography and magnetic resonance imaging--case report and review of literature.

    PubMed

    Bertoldi, Eduardo Gehling; Severo, Mateus Dornelles; Scheffel, Rafael Selbach; Foppa, Murilo; de Azevedo, Mirela Jobim; Maia, Ana Luiza

    2012-02-01

    Intracardiac metastases of thyroid carcinoma are a rare event. Their incidence is low in large autopsy series, and antemortem diagnosis is even less common. We present the case of a woman with advanced poorly differentiated thyroid carcinoma who had extensive intracardiac metastases. This case highlights the usefulness of echocardiography and magnetic resonance imaging in the diagnosis and differential diagnosis of cardiac metastases.

  15. Virtual special issue: Magnetic resonance at low fields

    NASA Astrophysics Data System (ADS)

    Blümich, Bernhard

    2017-01-01

    It appears to be a common understanding that low magnetic fields need to be avoided in magnetic resonance, as sensitivity and the frequency dispersion of the chemical shift increase with increasing field strength. But there many reasons to explore magnetic resonance at low fields. The instrumentation tends to be far less expensive than high-field equipment, magnets are smaller and lighter, internal gradients in heterogeneous media are smaller, conductive media and even metals become transparent at low frequencies to electromagnetic fields, and new physics and phenomena await to be discovered. On account of an increasing attention of the scientific community to magnetic resonance at low field, we have decided to launch JMR's Virtual Special Issue Series with this compilation about Low-Field Magnetic Resonance. This topic, for which we have chosen to focus on articles reporting measurements at fields lower than 2 T, is of widespread interest to our readership. We are therefore happy to offer to this constituency a selected outlook based on papers published during the last five years (volumes 214-270) in the pages of The Journal of Magnetic Resonance. A brief survey of the topics covered in this Virtual Special Issue follows.

  16. Dissipation and resonance frequency shift of a resonator magnetically coupled to a semiclassical spin

    PubMed Central

    de Voogd, J. M.; Wagenaar, J. J. T.; Oosterkamp, T. H.

    2017-01-01

    We calculate the change of the properties of a resonator, when coupled to a semiclassical spin by means of the magnetic field. Starting with the Lagrangian of the complete system, we provide an analytical expression for the linear response function for the motion in the case of a mechanical resonator and the current for the case of an electromagnetic resonator, thereby considering the influence of the resonator on the spin and vice versa. This analysis shows that the resonance frequency and effective dissipation factor can change significantly due to the relaxation times of the spin. We first derive this for a system consisting of a spin and mechanical resonator and thereafter apply the same calculations to an electromagnetic resonator. Moreover, the applicability of the method is generalized to a resonator coupled to two-level systems and more, providing a key to understand some of the problems of two-level systems in quantum devices. PMID:28186145

  17. Dissipation and resonance frequency shift of a resonator magnetically coupled to a semiclassical spin

    NASA Astrophysics Data System (ADS)

    de Voogd, J. M.; Wagenaar, J. J. T.; Oosterkamp, T. H.

    2017-02-01

    We calculate the change of the properties of a resonator, when coupled to a semiclassical spin by means of the magnetic field. Starting with the Lagrangian of the complete system, we provide an analytical expression for the linear response function for the motion in the case of a mechanical resonator and the current for the case of an electromagnetic resonator, thereby considering the influence of the resonator on the spin and vice versa. This analysis shows that the resonance frequency and effective dissipation factor can change significantly due to the relaxation times of the spin. We first derive this for a system consisting of a spin and mechanical resonator and thereafter apply the same calculations to an electromagnetic resonator. Moreover, the applicability of the method is generalized to a resonator coupled to two-level systems and more, providing a key to understand some of the problems of two-level systems in quantum devices.

  18. Magnetic Resonance Imaging (MRI) (For Parents)

    MedlinePlus

    ... painless test that uses a magnetic field and radio waves to produce detailed pictures of the body's ... in hospitals and radiology centers. During the examination, radio waves manipulate the magnetic position of the atoms ...

  19. Least Squares Magnetic-Field Optimization for Portable Nuclear Magnetic Resonance Magnet Design

    SciTech Connect

    Paulsen, Jeffrey L; Franck, John; Demas, Vasiliki; Bouchard, Louis-S.

    2008-03-27

    Single-sided and mobile nuclear magnetic resonance (NMR) sensors have the advantages of portability, low cost, and low power consumption compared to conventional high-field NMR and magnetic resonance imaging (MRI) systems. We present fast, flexible, and easy-to-implement target field algorithms for mobile NMR and MRI magnet design. The optimization finds a global optimum ina cost function that minimizes the error in the target magnetic field in the sense of least squares. When the technique is tested on a ring array of permanent-magnet elements, the solution matches the classical dipole Halbach solution. For a single-sided handheld NMR sensor, the algorithm yields a 640 G field homogeneous to 16 100 ppm across a 1.9 cc volume located 1.5 cm above the top of the magnets and homogeneous to 32 200 ppm over a 7.6 cc volume. This regime is adequate for MRI applications. We demonstrate that the homogeneous region can be continuously moved away from the sensor by rotating magnet rod elements, opening the way for NMR sensors with adjustable"sensitive volumes."

  20. Terahertz Magnetic Mirror Realized with Dielectric Resonator Antennas.

    PubMed

    Headland, Daniel; Nirantar, Shruti; Withayachumnankul, Withawat; Gutruf, Philipp; Abbott, Derek; Bhaskaran, Madhu; Fumeaux, Christophe; Sriram, Sharath

    2015-11-25

    Single-crystal silicon is bonded to a metal-coated substrate and etched in order to form an array of microcylinder passive terahertz dielectric resonator antennas (DRAs). The DRAs exhibit a magnetic response, and hence the array behaves as an efficient artificial magnetic conductor (AMC), with potential for terahertz antenna and sensing applications.

  1. High-Resolution Nuclear Magnetic Resonance of Solids.

    ERIC Educational Resources Information Center

    Maciel, Gary E.

    1984-01-01

    Examines recent developments in techniques for obtaining high-resolution nuclear magnetic resonance (NMR) spectra on solid samples, discussing the kinds of applications for which these techniques are well suited. Also discusses the characteristics of NMR of solids and generating magnetization for NMR in solids. (JN)

  2. The Nobel Prize in Medicine for Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Fry, Charles G.

    2004-01-01

    Nobel Prize in Medicine awarded in December 2003 to chemist Paul C. Lauterbur and physicist Peter Mansfield for the development of magnetic resonance imaging (MRI), a long overdue recognition of the huge impact MRI has had in medical diagnostics and research is mentioned. MRI was derived, and remains an extension of nuclear magnetic resonance…

  3. Parametric resonance induced chaos in magnetic damped driven pendulum

    NASA Astrophysics Data System (ADS)

    Khomeriki, Giorgi

    2016-07-01

    A damped driven pendulum with a magnetic driving force, appearing from a solenoid, where ac current flows is considered. The solenoid acts on the magnet, which is located at a free end of the pendulum. In this system the existence and interrelation of chaos and parametric resonance is theoretically examined. Derived analytical results are supported by numerical simulations and conducted experiments.

  4. All-fiber magnetic-field sensor based on microfiber knot resonator and magnetic fluid.

    PubMed

    Li, Xianli; Ding, Hui

    2012-12-15

    All-fiber magnetic-field sensor based on a device consisting of a microfiber knot resonator and magnetic fluid is proposed for the first time in this Letter. Sensor principles and package technology are introduced in detail. Experimental results show that the resonance wavelength of the proposed sensor regularly varies with changes to the applied magnetic field. When the magnetic field is increased to 600 Oe, the wavelength shift reaches nearly 100 pm. Moreover, the sensor responding to the 50 Hz alternating magnetic field is also experimentally investigated, and a minimal detectable magnetic-field strength of 10 Oe is successfully achieved.

  5. A Faraday effect position sensor for interventional magnetic resonance imaging.

    PubMed

    Bock, M; Umathum, R; Sikora, J; Brenner, S; Aguor, E N; Semmler, W

    2006-02-21

    An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.

  6. Magnetic resonance imaging of pediatric brain tumors: state of the art.

    PubMed

    Poussaint, T Y

    2001-12-01

    Over the past 25 years, magnetic resonance imaging (MRI) has developed into the primary imaging tool for evaluation of the central nervous system. MRI is the essential imaging study in the twenty-first century for the evaluation of the child with a brain tumor for initial preoperative diagnosis, treatment planning and image-guided therapies. This article provides an overview of the locations and MRI features of common pediatric tumors of childhood.

  7. Magnetic resonance imaging and laparoscopic management of an ovarian remnant in a bitch.

    PubMed

    Krauss, Z; Krauss, M

    2015-01-01

    Ovarian remnant tissue was diagnosed in a 6-year-old female Pointer presented with a history of periodic signs of oestrus after ovariohysterectomy. The diagnosis was based on clinical gynaecological examination, vaginoscopy, vaginal cytology, analysis of serum progesterone concentration, and magnetic resonance imaging. The ovarian remnant tissue was approached in a minimally invasive manner via laparoscopy and resected with a vessel-sealing system. The oestrus signs disappeared within 14 days after laparoscopy.

  8. Intraventricular mass lesions at magnetic resonance imaging: iconographic essay - part 2*

    PubMed Central

    de Castro, Felipe Damásio; Reis, Fabiano; Guerra, José Guilherme Giocondo

    2014-01-01

    The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (colloid cyst, oligodendroglioma, astroblastoma, lipoma, cavernoma) and of inflammatory/infectious lesions (neurocysticercosis and an atypical presentation of neurohistoplasmosis). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some imaging patterns that may facilitate the differential diagnosis. PMID:25741092

  9. Magnetic Resonance Imaging and Other Imaging Modalities in Diagnostic and Tumor Response Evaluation.

    PubMed

    Lambregts, Doenja M J; Maas, Monique; Stokkel, Marcel P M; Beets-Tan, Regina G H

    2016-07-01

    Functional imaging is emerging as a valuable contributor to the clinical management of patients with rectal cancer. Techniques such as diffusion-weighted magnetic resonance imaging, perfusion imaging, and positron emission tomography can offer meaningful insights into tissue architecture, vascularity, and metabolism. Moreover, new techniques targeting other aspects of tumor biology are now being developed and studied. This study reviews the potential role of functional imaging for the diagnosis, treatment monitoring, and assessment of prognosis in patients with rectal cancer.

  10. Magnetic Resonance Imaging of the Central Nervous System—An Update

    PubMed Central

    Brant-Zawadzki, Michael; Norman, David; Newton, T. Hans; Kucharczyk, Walter

    1985-01-01

    Magnetic resonance imaging has developed rapidly and now has superior ability to detect and to characterize disease in the central nervous system without any significant biologic hazard. It is becoming the screening method of choice in the diagnosis of neoplasm, ischemia, hemorrhage, infection and degenerative and demyelinating diseases involving the central nervous system. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9. PMID:3976220

  11. Application of time-spatial labeling inversion pulse magnetic resonance imaging in the diagnosis of spontaneous intracranial hypotension due to high-flow cerebrospinal fluid leakage at C1-2

    PubMed Central

    Hattori, Natsuki; Inamasu, Joji; Nakae, Shunsuke; Hirose, Yuichi; Murayama, Kazuhiro

    2016-01-01

    Background: Spontaneous intracranial hypotension (SIH) due to cerebrospinal fluid (CSF) leakage at C1-2 poses diagnostic and therapeutic challenges to spine surgeons. Although computed tomography (CT) myelography has been the diagnostic imaging modality of choice for identifying the CSF leakage point, extradural CSF collection at C1-2 on conventional CT myelography or magnetic resonance imaging (MRI) may often be a false localizing sign. Case Description: The present study reports the successful application of time-spatial labeling inversion pulse (T-SLIP) MRI, which enabled the precise identification of the CSF leakage point at C1-2 in a 28-year-old woman with intractable SIH. After identifying the leakage point using both CT myelography and T-SLIP MRI, surgery was performed to seal the CSF leak. Intraoperatively, a pouch suggestive of an extradural arachnoid cyst around the left C2 nerve root was found, which was repaired by packing the pouch with muscle and fibrin glue. Clinical improvement was observed shortly after surgery, and postoperative imaging revealed the disappearance of the CSF leakage. Conclusions: T-SLIP MRI may provide useful information on the flow dynamics of CSF in SIH patients due to high-flow leakage. However, further experience is required to assess its sensitivity and specificity as an imaging modality for identifying CSF leakage points. PMID:28144490

  12. Magnetically tunable Mie resonance-based dielectric metamaterials.

    PubMed

    Bi, Ke; Guo, Yunsheng; Liu, Xiaoming; Zhao, Qian; Xiao, Jinghua; Lei, Ming; Zhou, Ji

    2014-11-11

    Electromagnetic materials with tunable permeability and permittivity are highly desirable for wireless communication and radar technology. However, the tunability of electromagnetic parameters is an immense challenge for conventional materials and metamaterials. Here, we demonstrate a magnetically tunable Mie resonance-based dielectric metamaterials. The magnetically tunable property is derived from the coupling of the Mie resonance of dielectric cube and ferromagnetic precession of ferrite cuboid. Both the simulated and experimental results indicate that the effective permeability and permittivity of the metamaterial can be tuned by modifying the applied magnetic field. This mechanism offers a promising means of constructing microwave devices with large tunable ranges and considerable potential for tailoring via a metamaterial route.

  13. Accelerated nanoscale magnetic resonance imaging through phase multiplexing

    SciTech Connect

    Moores, B. A.; Eichler, A. Takahashi, H.; Navaretti, P.; Degen, C. L.; Tao, Y.

    2015-05-25

    We report a method for accelerated nanoscale nuclear magnetic resonance imaging by detecting several signals in parallel. Our technique relies on phase multiplexing, where the signals from different nuclear spin ensembles are encoded in the phase of an ultrasensitive magnetic detector. We demonstrate this technique by simultaneously acquiring statistically polarized spin signals from two different nuclear species ({sup 1}H, {sup 19}F) and from up to six spatial locations in a nanowire test sample using a magnetic resonance force microscope. We obtain one-dimensional imaging resolution better than 5 nm, and subnanometer positional accuracy.

  14. Magnetically tunable Mie resonance-based dielectric metamaterials

    NASA Astrophysics Data System (ADS)

    Bi, Ke; Guo, Yunsheng; Liu, Xiaoming; Zhao, Qian; Xiao, Jinghua; Lei, Ming; Zhou, Ji

    2014-11-01

    Electromagnetic materials with tunable permeability and permittivity are highly desirable for wireless communication and radar technology. However, the tunability of electromagnetic parameters is an immense challenge for conventional materials and metamaterials. Here, we demonstrate a magnetically tunable Mie resonance-based dielectric metamaterials. The magnetically tunable property is derived from the coupling of the Mie resonance of dielectric cube and ferromagnetic precession of ferrite cuboid. Both the simulated and experimental results indicate that the effective permeability and permittivity of the metamaterial can be tuned by modifying the applied magnetic field. This mechanism offers a promising means of constructing microwave devices with large tunable ranges and considerable potential for tailoring via a metamaterial route.

  15. Broadband ferromagnetic resonance linewidth measurement of magnetic tunnel junction multilayers

    NASA Astrophysics Data System (ADS)

    Sierra, J. F.; Aliev, F. G.; Heindl, R.; Russek, S. E.; Rippard, W. H.

    2009-01-01

    The broadband ferromagnetic resonance (FMR) linewidth of the free layer of magnetic tunnel junctions is used as a simple diagnostic of the quality of the magnetic structure. The FMR linewidth increases near the field regions of free layer reversal and pinned layer reversal, and this increase correlates with an increase in magnetic hysteresis in unpatterned films, low-frequency noise in patterned devices, and previous observations of magnetic domain ripple by use of Lorentz microscopy. Postannealing changes the free layer FMR linewidth, indicating that considerable magnetic disorder, originating in the exchange-biased pinned layer, is transferred to the free layer.

  16. Catheter steering using a Magnetic Resonance Imaging system.

    PubMed

    Lalande, Viviane; Gosselin, Frederick P; Martel, Sylvain

    2010-01-01

    A catheter is successfully bent and steered by applying magnetic gradients inside a Magnetic Resonance Imaging system (MRI). One to three soft ferromagnetic spheres are attached at the distal tip of the catheter with different spacing between the spheres. Depending on the interactions between the spheres, progressive or discontinuous/jumping displacement was observed for increasing magnetic load. This phenomenon is accurately predicted by a simple theoretical dipole interaction model.

  17. Spin microscope based on optically detected magnetic resonance

    DOEpatents

    Berman, Gennady P.; Chernobrod, Boris M.

    2010-07-13

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  18. Spin microscope based on optically detected magnetic resonance

    DOEpatents

    Berman, Gennady P.; Chernobrod, Boris M.

    2010-06-29

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  19. Spin microscope based on optically detected magnetic resonance

    DOEpatents

    Berman, Gennady P.; Chernobrod, Boris M.

    2009-11-10

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of impaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  20. Spin microscope based on optically detected magnetic resonance

    DOEpatents

    Berman, Gennady P.; Chernobrod, Boris M.

    2007-12-11

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  1. Spin microscope based on optically detected magnetic resonance

    SciTech Connect

    Berman, Gennady P.; Chernobrod, Boris M.

    2009-10-27

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  2. Characterization of magnetically actuated resonant cantilevers in viscous fluids

    NASA Astrophysics Data System (ADS)

    Vančura, Cyril; Lichtenberg, Jan; Hierlemann, Andreas; Josse, Fabien

    2005-10-01

    The vibration behavior of magnetically actuated resonant microcantilevers immersed in viscous fluids has been studied. A dependence of the resonance frequency and the quality factor (Q factor) on the fluid properties, such as density and viscosity and on the cantilever geometry is described. Various cantilever geometries are analyzed in pure water and glycerol solutions, and the results are explained in terms of the added displaced fluid mass and the fluid damping force for both the resonance frequency and the quality factor. An in-depth knowledge and understanding of such systems is necessary when analyzing resonant cantilevers as biochemical sensors in liquid environments.

  3. New oil-in-water magnetic emulsion as contrast agent for in vivo magnetic resonance imaging (MRI).

    PubMed

    Ahmed, Naveed; Jaafar-Maalej, Chiraz; Eissa, Mohamed Mahmoud; Fessi, Hatem; Elaissari, Abdelhamid

    2013-09-01

    Nowadays, bio-imaging techniques are widely applied for the diagnosis of various diseased/tumoral tissues in the body using different contrast agents. Accordingly, the advancement in bionanotechnology research is enhanced in this regard. Among contrast agents used, superparamagnetic iron oxide nanoparticles were developed by many researchers and applied for in vive magnetic resonance imaging (MRI). In this study, a new oil-in-water magnetic emulsion was used as contrast agent in MRI, after being characterized in terms of particle size, iron oxide content, magnetic properties and colloidal stability using dynamic light scattering (DLS), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM) and zeta potential measurement techniques, respectively. The hydrodynamic size and magnetic content of the magnetic colloidal particles were found to be 250 nm and 75 wt%, respectively. In addition, the used magnetic emulsion possesses superparamagentic properties and high colloidal stability in aqueous medium. Then, the magnetic emulsion was highly diluted and administered intravenously to the Sprague dawley rats to be tested as contrast agent for in vivo MRI. In this preliminary study, MRI images showed significant enhancement in contrast, especially for T2 (relaxation time) contrast enhancement, indicating the distribution of magnetic colloidal nanoparticles within organs, like liver, spleen and kidneys of the Sprague dawley rats. In addition, it was found that 500 microL of the highly diluted magnetic emulsion (0.05 wt%) was found adequate for MRI analysis. This seems to be useful for further investigations especially in theranostic applications of magnetic emulsion.

  4. Magnetic resonance imaging characteristics of equine head disorders: 84 cases (2000-2013).

    PubMed

    Manso-Díaz, Gabriel; Dyson, Sue J; Dennis, Ruth; García-López, José M; Biggi, Marianna; García-Real, M Isabel; San Román, Fidel; Taeymans, Olivier

    2015-01-01

    The equine head is an anatomically complex area, therefore advanced tomographic imaging techniques, such as computed tomography or magnetic resonance imaging (MRI), are often required for diagnosis and treatment planning. The purpose of this multicenter retrospective study was to describe MRI characteristics for a large sample of horses with head disorders. Horses imaged over a period of 13 years were recruited. Eighty-four horses met the inclusion criteria, having neurological (n = 65), sinonasal (n = 14), and soft tissue (n = 5) disorders. Magnetic resonance imaging accurately depicted the anatomy and allowed identification of the primary lesion and associated changes. There were good correlations between MRI findings and intraoperative or postmortem results. Magnetic resonance imaging showed the exact localization of the lesions, their size, and relation to surrounding structures. However, in the neurological group, there were 45 horses with no MRI abnormalities, 29 of which had a history of recurrent seizures, related to cryptogenic epilepsy. Magnetic resonance imaging was otherwise a valuable diagnostic tool, and can be used for studying a broad range of head disorders using either low-field or high-field magnets.

  5. Nuclear magnetic resonance spectroscopy with single spin sensitivity

    PubMed Central

    Müller, C.; Kong, X.; Cai, J.-M.; Melentijević, K.; Stacey, A.; Markham, M.; Twitchen, D.; Isoya, J.; Pezzagna, S.; Meijer, J.; Du, J. F.; Plenio, M. B.; Naydenov, B.; McGuinness, L. P.; Jelezko, F.

    2014-01-01

    Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen–vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four 29Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds. PMID:25146503

  6. Quantum transport in coupled resonators enclosed synthetic magnetic flux

    NASA Astrophysics Data System (ADS)

    Jin, L.

    2016-07-01

    Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov-Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms.

  7. One-pot synthesis of magnetic nanoclusters enabling atherosclerosis-targeted magnetic resonance imaging.

    PubMed

    Kukreja, Aastha; Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Lee, Taeksu; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

    2014-01-01

    In this study, dextran-encrusted magnetic nanoclusters (DMNCs) were synthesized using a one-pot solution phase method for detection of atherosclerosis by magnetic resonance imaging. Pyrenyl dextran was used as a surfactant because of its electron-stabilizing effect and its amphiphilic nature, rendering the DMNCs stable and water-dispersible. The DMNCs were 65.6±4.3 nm, had a narrow size distribution, and were superparamagnetic with a high magnetization value of 60.1 emu/g. Further, they showed biocompatibility and high cellular uptake efficiency, as indicated by a strong interaction between dextran and macrophages. In vivo magnetic resonance imaging demonstrated the ability of DMNCs to act as an efficient magnetic resonance imaging contrast agent capable of targeted detection of atherosclerosis. In view of these findings, it is concluded that DMNCs can be used as magnetic resonance imaging contrast agents to detect inflammatory disease.

  8. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy Characterize a Rodent Model of Covert Stroke

    NASA Astrophysics Data System (ADS)

    Herrera, Sheryl Lyn

    Covert stroke (CS) comprises lesions in the brain often associated by risk factors such as a diet high in fat, salt, cholesterol and sugar (HFSCS). Developing a rodent model for CS incorporating these characteristics is useful for developing and testing interventions. The purpose of this thesis was to determine if magnetic resonance (MR) can detect brain abnormalities to confirm this model will have the desired anatomical effects. Ex vivo MR showed brain abnormalities for rats with the induced lesions and fed the HFSCS diet. Spectra acquired on the fixed livers had an average percent area under the fat peak relative to the water peak of (20+/-4)% for HFSCS and (2+/-2)% for control. In vivo MR images had significant differences between surgeries to induce the lesions (p=0.04). These results show that applying MR identified abnormalities in the rat model and therefore is important in the development of this CS rodent model.

  9. Towards Single Biomolecule Imaging via Optical Nanoscale Magnetic Resonance Imaging.

    PubMed

    Boretti, Alberto; Rosa, Lorenzo; Castelletto, Stefania

    2015-09-09

    Nuclear magnetic resonance (NMR) spectroscopy is a physical marvel in which electromagnetic radiation is charged and discharged by nuclei in a magnetic field. In conventional NMR, the specific nuclei resonance frequency depends on the strength of the magnetic field and the magnetic properties of the isotope of the atoms. NMR is routinely utilized in clinical tests by converting nuclear spectroscopy in magnetic resonance imaging (MRI) and providing 3D, noninvasive biological imaging. While this technique has revolutionized biomedical science, measuring the magnetic resonance spectrum of single biomolecules is still an intangible aspiration, due to MRI resolution being limited to tens of micrometers. MRI and NMR have, however, recently greatly advanced, with many breakthroughs in nano-NMR and nano-MRI spurred by using spin sensors based on an atomic impurities in diamond. These techniques rely on magnetic dipole-dipole interactions rather than inductive detection. Here, novel nano-MRI methods based on nitrogen vacancy centers in diamond are highlighted, that provide a solution to the imaging of single biomolecules with nanoscale resolution in-vivo and in ambient conditions.

  10. Quantum transport in coupled resonators enclosed synthetic magnetic flux

    SciTech Connect

    Jin, L.

    2016-07-15

    Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov–Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms. -- Highlights: •The light transport is investigated through ring array of coupled resonators enclosed synthetic magnetic field. •Aharonov–Bohm ring interferometer of arbitrary configuration is investigated. •The half-integer magnetic flux quantum leads to destructive interference and transmission zeros for two-arm at equal length. •Complete transmission is available via tuning synthetic magnetic flux.

  11. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    SciTech Connect

    Tomimatsu, Toru Shirai, Shota; Hashimoto, Katsushi Sato, Ken; Hirayama, Yoshiro

    2015-08-15

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  12. The use of magnetic resonance spectroscopy and magnetic resonance imaging in alcohol research.

    PubMed

    Nagel, Bonnie J; Kroenke, Christopher D

    2008-01-01

    The recent emergence of magnetic resonance (MR)-based neuroimaging techniques has dramatically improved researchers' ability to understand the neuropathology of alcoholism. These techniques range from those that directly monitor the metabolism and the biochemical and physiological effects (i.e., the pharmacodynamics) of alcohol within the brain to techniques that examine the impact of heavy alcohol use on brain structure and function. In general, MR-based techniques measure electromagnetic signals (the same type of signals detected by a radio antenna) generated by nuclei of endogenous molecules in the body of a person placed in a powerful magnet field. When influenced by a magnet, tissue itself transiently becomes magnetic. In part, this is because of the properties of atomic nuclei. Different MR-based techniques have been developed to utilize nuclear magnetism induced in tissue to generate images of internal structure. The most commonly used MR imaging (MRI) techniques rely on signals derived from hydrogen nuclei in water, which is by far the most concentrated molecular species in the body. The physical properties of water molecules vary from one region of tissue to another, and this influences the nuclear magnetism generated by water hydrogen nuclei. As a result, MRI can differentiate regions in soft tissue at a high level of detail. A second approach-MR spectroscopy (MRS)- uses the same strategy to detect electromagnetic signals, but they are derived from nuclei of atoms (hydrogen as well as some other atoms) on molecules other than water, such as lipids, amino acids, or even alcohol (i.e., ethanol). The resulting data on the molecule(s) under investigation can provide detailed information about the metabolic activity of various tissues, including the brain. The main advantage of MR-based techniques is that they do not expose the subject to radioactive tracers and therefore can be used repeatedly in the same subject, allowing researchers to track metabolic or

  13. Three-dimensional magnetic recording using ferromagnetic resonance

    NASA Astrophysics Data System (ADS)

    Suto, Hirofumi; Kudo, Kiwamu; Nagasawa, Tazumi; Kanao, Taro; Mizushima, Koichi; Sato, Rie

    2016-07-01

    To meet the ever-increasing demand for data storage, future magnetic recording devices will need to be made three-dimensional by implementing multilayer recording. In this article, we present methods of detecting and manipulating the magnetization direction of a specific layer selectively in a vertically stacked multilayer magnetic system, which enable layer-selective read and write operations in three-dimensional magnetic recording devices. The principle behind the methods is ferromagnetic resonance excitation in a microwave magnetic field. By designing each magnetic recording layer to have a different ferromagnetic resonance frequency, magnetization excitation can be induced individually in each layer by tuning the frequency of an applied microwave magnetic field, and this selective magnetization excitation can be utilized for the layer-selective operations. Regarding media for three-dimensional recording, when layers of a perpendicular magnetic material are vertically stacked, dipolar interaction between multiple recording layers arises and is expected to cause problems, such as degradation of thermal stability and switching field distribution. To solve these problems, we propose the use of an antiferromagnetically coupled structure consisting of hard and soft magnetic layers. Because the stray fields from these two layers cancel each other, antiferromagnetically coupled media can reduce the dipolar interaction.

  14. Sclerosing liposarcoma of epididymis: Role of chemical shift magnetic resonance imaging

    PubMed Central

    Ramanathan, Subramaniyan; Raghu, Vineetha; Kumar, Devendra; Sempiege, Venkata R P

    2016-01-01

    Sclerosing liposarcoma of epididymis is a rare extratesticular scrotal tumor with variable prognosis. Ultrasonography is the initial imaging modality of choice for the evaluation of scrotal mass and helps to differentiate testicular and extratesticular masses, thereby narrowing down the differential diagnosis. Magnetic resonance imaging with its excellent soft tissue resolution can help in the further characterization of the nature of the tumor. In this case report, we highlight the role of chemical shift imaging in making a confident preoperative diagnosis of liposarcoma thereby guiding optimal and timely management. PMID:27857462

  15. Computed tomography and magnetic resonance imaging of cat-scratch disease: a report of two cases.

    PubMed

    Wang, Chih-Wei; Chang, Wei-Chou; Chao, Tai-Kuang; Liu, Chia-Chen; Huang, Guo-Shu

    2009-01-01

    Cat-scratch disease (CSD) is a bacterial infection that typically causes swelling of the lymph nodes. The patients usually have a history of being scratched, bitten, or licked by cats and often by kittens. Understanding the characteristic radiological and clinical features may lead to a noninvasive diagnosis and prevent unnecessary invasive procedures. We report two cases of CSD with computed tomography and magnetic resonance imaging showing nodules or masses of lymphadenopathy with subcutaneous edema and fat infiltration in the lymphatic drainage area. The imaging features and clinical manifestations are described, and the differential diagnosis of CSD is discussed.

  16. Color-coded visualization of magnetic resonance imaging multiparametric maps

    NASA Astrophysics Data System (ADS)

    Kather, Jakob Nikolas; Weidner, Anja; Attenberger, Ulrike; Bukschat, Yannick; Weis, Cleo-Aron; Weis, Meike; Schad, Lothar R.; Zöllner, Frank Gerrit

    2017-01-01

    Multiparametric magnetic resonance imaging (mpMRI) data are emergingly used in the clinic e.g. for the diagnosis of prostate cancer. In contrast to conventional MR imaging data, multiparametric data typically include functional measurements such as diffusion and perfusion imaging sequences. Conventionally, these measurements are visualized with a one-dimensional color scale, allowing only for one-dimensional information to be encoded. Yet, human perception places visual information in a three-dimensional color space. In theory, each dimension of this space can be utilized to encode visual information. We addressed this issue and developed a new method for tri-variate color-coded visualization of mpMRI data sets. We showed the usefulness of our method in a preclinical and in a clinical setting: In imaging data of a rat model of acute kidney injury, the method yielded characteristic visual patterns. In a clinical data set of N = 13 prostate cancer mpMRI data, we assessed diagnostic performance in a blinded study with N = 5 observers. Compared to conventional radiological evaluation, color-coded visualization was comparable in terms of positive and negative predictive values. Thus, we showed that human observers can successfully make use of the novel method. This method can be broadly applied to visualize different types of multivariate MRI data.

  17. Does Magnetic Resonance Imaging belong to physicians or physicists?

    NASA Astrophysics Data System (ADS)

    Leroy-Willig, Anne; Morvan, Daniel; Guillot, Geneviève

    Magnetic Resonance Imaging, proposed in 1973, has been developed very rapidly, mostly as a medical diagnosis technique, during the ten last years. It now allows applications such as fast imaging in less than one second, visualization of blood vessels, localized measurement of physical and chemical parameters on living systems. Now these applications spread out of the biological field and physicists use it to the study of hydrodynamics, materials, and more generally systems where a solid phase interacts with water. L'imagerie par Résonance Magnétique a connu depuis 1973 un développement très rapide, orienté essentiellement vers des applications médicales. Il est possible maintenant de réaliser des images en une fraction de seconde, de visualiser des vaisseaux sanguins sans injection de produit de contraste, de mesurer les valeurs locales de paramètres physiques et chimiques dans des systèmes vivants. L'évolution récente de cette technique est son utilisation pour l'exploration de systèmes physiques: études hydrodynamiques, caractérisation de matériaux et plus généralement de systèmes dans lesquels l'eau interagit avec une phase solide.

  18. Magnetic resonance imaging and contrast enhancement. Scientific report

    SciTech Connect

    Swenberg, C.E.; Movius, E.G.

    1988-01-01

    Chapters II through VI of this report discuss: Relaxation of Nuclear Spins; Echo Techniques; Basic Imaging Pulse Sequences; Partial Saturation Recovery; Inversion Recovery; Spin Echo; Effects of Pulse Sequence on Image Contrast; Contrast Agents; Theoretical Aspects; Pharmacokinetics and Toxicity; and Physiological Rationale for Agent Selection. One of the major goals in all medical imaging techniques is to maximize one's ability to visualize and differentiate adjacent tissue regions in the body on the basis of differences in anatomy, physiology, or various pathological processes. Magnetic resonance (MR) imaging offers distinct advantages over conventional x-ray imaging because of the possibility of selecting specific pulse sequences that can differentiate adjacent structures on the basis of differences in proton density, T/sub 1/ or T/sub 2/ relaxation rates, or flow. As a result of applying these various pulse sequences, numerous images have been obtained of the brain and other organs that demonstrate considerably more-detailed anatomical structure than had previously been available with computerized tomography, ultrasound, or nuclear medicine techniques. In some situations it is clearly superior, such as in the diagnosis of multiple sclerosis.

  19. The simulation of magnetic resonance elastography through atherosclerosis.

    PubMed

    Thomas-Seale, L E J; Hollis, L; Klatt, D; Sack, I; Roberts, N; Pankaj, P; Hoskins, P R

    2016-06-14

    The clinical diagnosis of atherosclerosis via the measurement of stenosis size is widely acknowledged as an imperfect criterion. The vulnerability of an atherosclerotic plaque to rupture is associated with its mechanical properties. The potential to image these mechanical properties using magnetic resonance elastography (MRE) was investigated through synthetic datasets. An image of the steady state wave propagation, equivalent to the first harmonic, can be extracted directly from finite element analysis. Inversion of this displacement data yields a map of the shear modulus, known as an elastogram. The variation of plaque composition, stenosis size, Gaussian noise, filter thresholds and excitation frequency were explored. A decreasing mean shear modulus with an increasing lipid composition was identified through all stenosis sizes. However the inversion algorithm showed sensitivity to parameter variation leading to artefacts which disrupted both the elastograms and quantitative trends. As noise was increased up to a realistic level, the contrast was maintained between the fully fibrous and lipid plaques but lost between the interim compositions. Although incorporating a Butterworth filter improved the performance of the algorithm, restrictive filter thresholds resulted in a reduction of the sensitivity of the algorithm to composition and noise variation. Increasing the excitation frequency improved the techniques ability to image the magnitude of the shear modulus and identify a contrast between compositions. In conclusion, whilst the technique has the potential to image the shear modulus of atherosclerotic plaques, future research will require the integration of a heterogeneous inversion algorithm.

  20. Image fusion for dynamic contrast enhanced magnetic resonance imaging

    PubMed Central

    Twellmann, Thorsten; Saalbach, Axel; Gerstung, Olaf; Leach, Martin O; Nattkemper, Tim W

    2004-01-01

    Background Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms. Methods In this paper, image fusion based on Kernel Principal Component Analysis (KPCA) is proposed for the first time. It is demonstrated that a priori knowledge about the data domain can be easily incorporated into the parametrisation of the KPCA, leading to task-oriented visualisations of the multivariate data. The results of the fusion process are compared with those of the well-known and established standard linear Principal Component Analysis (PCA) by means of temporal sequences of 3D MRI volumes from six patients who took part in a breast cancer screening study. Results The PCA and KPCA algorithms are able to integrate information from a sequence of MRI volumes into informative gray value or colour images. By incorporating a priori knowledge, the fusion process can be automated and optimised in order to visualise suspicious lesions with high contrast to normal tissue. Conclusion Our machine learning based image fusion approach maps the full signal space of a temporal DCE-MRI sequence to a single meaningful visualisation with good tissue/lesion contrast and thus supports the radiologist during manual image evaluation. PMID:15494072

  1. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    SciTech Connect

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J. )

    1991-03-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain.

  2. Color-coded visualization of magnetic resonance imaging multiparametric maps

    PubMed Central

    Kather, Jakob Nikolas; Weidner, Anja; Attenberger, Ulrike; Bukschat, Yannick; Weis, Cleo-Aron; Weis, Meike; Schad, Lothar R.; Zöllner, Frank Gerrit

    2017-01-01

    Multiparametric magnetic resonance imaging (mpMRI) data are emergingly used in the clinic e.g. for the diagnosis of prostate cancer. In contrast to conventional MR imaging data, multiparametric data typically include functional measurements such as diffusion and perfusion imaging sequences. Conventionally, these measurements are visualized with a one-dimensional color scale, allowing only for one-dimensional information to be encoded. Yet, human perception places visual information in a three-dimensional color space. In theory, each dimension of this space can be utilized to encode visual information. We addressed this issue and developed a new method for tri-variate color-coded visualization of mpMRI data sets. We showed the usefulness of our method in a preclinical and in a clinical setting: In imaging data of a rat model of acute kidney injury, the method yielded characteristic visual patterns. In a clinical data set of N = 13 prostate cancer mpMRI data, we assessed diagnostic performance in a blinded study with N = 5 observers. Compared to conventional radiological evaluation, color-coded visualization was comparable in terms of positive and negative predictive values. Thus, we showed that human observers can successfully make use of the novel method. This method can be broadly applied to visualize different types of multivariate MRI data. PMID:28112222

  3. Neuromorphometry of primary brain tumors by magnetic resonance imaging

    PubMed Central

    Hevia-Montiel, Nidiyare; Rodriguez-Perez, Pedro I.; Lamothe-Molina, Paul J.; Arellano-Reynoso, Alfonso; Bribiesca, Ernesto; Alegria-Loyola, Marco A.

    2015-01-01

    Abstract. Magnetic resonance imaging is a technique for the diagnosis and classification of brain tumors. Discrete compactness is a morphological feature of two-dimensional and three-dimensional objects. This measure determines the compactness of a discretized object depending on the sum of the areas of the connected voxels and has been used for understanding the morphology of nonbrain tumors. We hypothesized that regarding brain tumors, we may improve the malignancy grade classification. We analyzed the values in 20 patients with different subtypes of primary brain tumors: astrocytoma, oligodendroglioma, and glioblastoma multiforme subdivided into the contrast-enhanced and the necrotic tumor regions. The preliminary results show an inverse relationship between the compactness value and the malignancy grade of gliomas. Astrocytomas exhibit a mean of 973±14, whereas oligodendrogliomas exhibit a mean of 942±21. In contrast, the contrast-enhanced region of the glioblastoma presented a mean of 919±43, and the necrotic region presented a mean of 869±66. However, the volume and area of the enclosing surface did not show a relationship with the malignancy grade of the gliomas. Discrete compactness appears to be a stable characteristic between primary brain tumors of different malignancy grades, because similar values were obtained from different patients with the same type of tumor. PMID:26158107

  4. Performance of magnetic resonance angiography in suspected acute pulmonary embolism.

    PubMed

    Blum, Alain; Bellou, Abdelouahab; Guillemin, Francis; Douek, Philippe; Laprévote-Heully, Marie-Claude; Wahl, Denis

    2005-03-01

    Pulmonary embolism (PE) is a common and potentially fatal disorder. Non-specific findings make the clinical diagnosis of PE difficult. To assess the diagnostic value and inter-observer agreement of magnetic resonance angiography (MRA) in a cohort of patients with suspected PE, we conducted a prospective clinical study. MRA was compared for sensitivity and specificity to a diagnostic strategy including clinical probability, D-dimer testing, spiral CT, ultrasound leg compression and pulmonary angiography. A total of 89 patients with clinically suspected PE were included: the clinical probability of PE was intermediate or high in 78, and low in the remaining 11. All patients underwent monoor multi-slice spiral CT and MRA with gadolinium injection (both within 24 hours of entry to the study). Anticoagulation was withheld in patients concerned about the strategy. All subjects were followed up for 3 months. MRA was read independently by two experienced teams of radiologists: one local and one from another university centre. Spiral CT was positive in 62 of 63 cases of confirmed PE. No patient with negative CT findings was positive ultrasonographically. Only one patient with a negative CT (and negative ultrasound) had a recurrent thromboembolic event. The first team diagnosed PE with MRA in 47 cases, with a sensitivity of 71% and a specificity of 92%; the second team obtained the diagnosis in 23 cases, with a sensitivity of 31% and a specificity of 85%. Inter-observer agreement between MRA reading was low: Kappa = 0.16 (-0.01 to 0.33); p = 0.07. In conclusion, compared with a non-invasive strategy based on spiral CT, the diagnostic value of MRA is limited by poor inter-observer agreement.

  5. Design and development of a novel nuclear magnetic resonance detection for the gas phase ions by magnetic resonance acceleration technique

    NASA Astrophysics Data System (ADS)

    Fuke, K.; Tona, M.; Fujihara, A.; Sakurai, M.; Ishikawa, H.

    2012-08-01

    Nuclear magnetic resonance (NMR) technique is a well-established powerful tool to study the physical and chemical properties of a wide range of materials. However, presently, NMR applications are essentially limited to materials in the condensed phase. Although magnetic resonance was originally demonstrated in gas phase molecular beam experiments, no application to gas phase molecular ions has yet been demonstrated. Here, we present a novel principle of NMR detection for gas phase ions based on a "magnetic resonance acceleration" technique and describe the design and construction of an apparatus which we are developing. We also present an experimental technique and some results on the formation and manipulation of cold ion packets in a strong magnetic field, which are the key innovations to detect NMR signal using the present method. We expect this novel method to lead new realm for the study of mass-selected gas-phase ions with interesting applications in both fundamental and applied sciences.

  6. Dynamic magnetic susceptibility and electrical detection of ferromagnetic resonance

    NASA Astrophysics Data System (ADS)

    Zhang, Yin; Wang, X. S.; Yuan, H. Y.; Kang, S. S.; Zhang, H. W.; Wang, X. R.

    2017-03-01

    The dynamic magnetic susceptibility of magnetic materials near ferromagnetic resonance (FMR) is very important in interpreting the dc voltage obtained in its electrical detection. Based on the causality principle and the assumption that the usual microwave absorption lineshape of a homogeneous magnetic material around FMR is Lorentzian, the general forms of the dynamic magnetic susceptibility of an arbitrary sample and the corresponding dc voltage lineshapes of its electrical detection were obtained. Our main findings are as follows. (1) The dynamic magnetic susceptibility is not a Polder tensor for a material with an arbitrary magnetic anisotropy. The two off-diagonal matrix elements of the tensor near FMR are not, in general, opposite to each other. However, the linear response coefficient of the magnetization to the total radio frequency (rf) field (the sum of the external and internal rf fields due to precessing magnetization is a quantity which cannot be measured directly) is a Polder tensor. This may explain why the two off-diagonal susceptibility matrix elements were always wrongly assumed to be opposite to each other in almost all analyses. (2) The frequency dependence of dynamic magnetic susceptibility near FMR is fully characterized by six real numbers, while its field dependence is fully characterized by seven real numbers. (3) A recipe of how to determine these numbers by standard microwave absorption measurements for a sample with an arbitrary magnetic anisotropy is proposed. Our results allow one to unambiguously separate the contribution of the anisotropic magnetoresistance to the dc voltage signals from the anomalous Hall effect. With these results, one can reliably extract the information of spin pumping and the inverse spin-Hall effect, and determine the spin-Hall angle. (4) In the case that resonance frequency is not sensitive to the applied static magnetic field, the field dependence of the matrix elements of dynamic magnetic susceptibility, as

  7. Spin torque ferromagnetic resonance with magnetic field modulation

    NASA Astrophysics Data System (ADS)

    Gonçalves, A. M.; Barsukov, I.; Chen, Y.-J.; Yang, L.; Katine, J. A.; Krivorotov, I. N.

    2013-10-01

    We demonstrate a technique of broadband spin torque ferromagnetic resonance (ST-FMR) with magnetic field modulation for measurements of spin wave properties in magnetic nanostructures. This technique gives great improvement in sensitivity over the conventional ST-FMR measurements, and application of this technique to nanoscale magnetic tunnel junctions (MTJs) reveals a rich spectrum of standing spin wave eigenmodes. Comparison of the ST-FMR measurements with micromagnetic simulations of the spin wave spectrum allows us to explain the character of low-frequency magnetic excitations in nanoscale MTJs.

  8. Current-induced spin torque resonance of a magnetic insulator

    NASA Astrophysics Data System (ADS)

    Schreier, Michael; Chiba, Takahiro; Niedermayr, Arthur; Lotze, Johannes; Huebl, Hans; Geprägs, Stephan; Takahashi, Saburo; Bauer, Gerrit E. W.; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2015-10-01

    We report the observation of current-induced spin torque resonance in yttrium iron garnet/platinum bilayers. An alternating charge current at GHz frequencies in the platinum gives rise to dc spin pumping and spin Hall magnetoresistance rectification voltages, induced by the Oersted fields of the ac current and the spin Hall effect-mediated spin transfer torque. In ultrathin yttrium iron garnet films, we observe spin transfer torque actuated magnetization dynamics which are significantly larger than those generated by the ac Oersted field. Spin transfer torques thus efficiently couple charge currents and magnetization dynamics also in magnetic insulators, enabling charge current-based interfacing of magnetic insulators with microwave devices.

  9. Some principles in choosing parameters of magnetic resonance tomographs

    NASA Astrophysics Data System (ADS)

    Volobuev, A. N.

    2017-01-01

    The problem of amplifying the signal that ensures the visualization of internal organs in the magnetic resonance tomograph due to the optimal selection of some of its parameters has been considered. The operating principle of the tomograph has been analyzed. The relation between the angle of the magnetic moment precession in hydrogen nuclei in an organism, the frequency of the ac magnetic field exciting this precession, and the constant magnetic field used has been determined using quantum-mechanical concepts. This relation makes it possible to determine the optimal parameters for tomograph operation.

  10. On-wafer magnetic resonance of magnetite nanoparticles

    NASA Astrophysics Data System (ADS)

    Little, Charles A. E.; Russek, Stephen E.; Booth, James C.; Kabos, Pavel; Usselman, Robert J.

    2015-11-01

    Magnetic resonance measurements of ferumoxytol and TEMPO were made using an on-wafer transmission line technique with a vector network analyzer, allowing for broadband measurements of small sample volumes (4 nL) and small numbers of spins (1 nmol). On-wafer resonance measurements were compared with standard single-frequency cavity-based electron paramagnetic resonance (EPR) measurements using a new power conservation approach and the results show similar line shape. On-wafer magnetic resonance measurements using integrated microfluidics and microwave technology can significantly reduce the cost and sample volumes required for EPR spectral analysis and allow for integration of EPR with existing lab-on-a-chip processing and characterization techniques for point-of-care medical diagnostic applications.

  11. Stacked magnetic resonators for MRI RF coils decoupling

    NASA Astrophysics Data System (ADS)

    Georget, Elodie; Luong, Michel; Vignaud, Alexandre; Giacomini, Eric; Chazel, Edouard; Ferrand, Guillaume; Amadon, Alexis; Mauconduit, Franck; Enoch, Stefan; Tayeb, Gérard; Bonod, Nicolas; Poupon, Cyril; Abdeddaim, Redha

    2017-02-01

    Parallel transmission is a very promising method to tackle B1+ field inhomogeneities at ultrahigh field in magnetic resonant imaging (MRI). This technique is however limited by the mutual coupling between the radiating elements. Here we propose to solve this problem by designing a passive magneto-electric resonator that we here refer to as stacked magnetic resonator (SMR). By combining numerical and experimental methodologies, we prove that this novelty passive solution allows an efficient decoupling of elements of a phased-array coil. We demonstrate the ability of this technique to significantly reduce by more than 10 dB the coupling preserving the quality of images compared to ideally isolated linear resonators on a spherical salty agar gel phantom in a 7 T MRI scanner.

  12. Simulation of a birdcage and a ceramic cavity HF-resonator for high magnetic fields in magnetic resonance imaging.

    PubMed

    Eriksen, E; Golombeck, M A; Junge, S; Dössel, O

    2002-01-01

    The aim of this work was the 3D-simulation of a dielectric resonator for high-field-MRI. A 12-rod-bird-cage-resonator was simulated in a first step, in order to verify the capability of the commercial simulation software MAFIA to simulate homogeneous, transversal B-fields in resonators. The second step was the simulation of frequency-independent dielectric ceramic resonators for static magnetic field strengths of 7 T and 12 T (294 MHz and 504 MHz respectively). The results were compared to the measured results of a manufactured TiO2- and a Al2O3-resonator. Only minor deviations showed up. These results led to the conclusion that dielectric resonators for high field MRI can be optimised using numerical field calculation software.

  13. Magnetic resonance spectroscopy and imaging for the study of fossils.

    PubMed

    Giovannetti, Giulio; Guerrini, Andrea; Salvadori, Piero A

    2016-07-01

    Computed tomography (CT) has long been used for investigating palaeontological specimens, as it is a nondestructive technique which avoids the need to dissolve or ionize the fossil sample. However, magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) have recently gained ground as analytical tools for examination of palaeontological samples, by nondestructively providing information about the structure and composition of fossils. While MRI techniques are able to reveal the three-dimensional geometry of the trace fossil, MRS can provide information on the chemical composition of the samples. The multidimensional nature of MR (magnetic resonance) signals has potential to provide rich three-dimensional data on the palaeontological specimens and also to help in elucidating paleopathological and paleoecological questions. In this work the verified applications and the emerging uses of MRI and MRS in paleontology are reviewed, with particular attention to fossil spores, fossil plants, ambers, fossil invertebrates, and fossil vertebrate studies.

  14. Coronary magnetic resonance imaging: current state-of-the-art.

    PubMed

    Appelbaum, Evan; Botnar, René M; Yeon, Susan B; Manning, Warren J

    2005-09-01

    Over the past decade, coronary magnetic resonance imaging has been transformed from a scientific curiosity to a clinically useful imaging tool for patients with known or suspected anomalous coronary arteries or coronary artery aneurysms and for assessment of coronary artery bypass graft patency. Coronary magnetic resonance imaging also appears to be of clinical value for assessment of native vessel integrity in selected patients, especially those patients with suspected left main/multivessel disease. Among patients referred for X-ray angiography, a normal coronary magnetic resonance imaging strongly suggests the absence of severe multivessel disease. Technical and methodological advances in motion suppression, along with increasing clinical experience will no doubt facilitate improved visualization of the distal and branch vessel.

  15. Magnetic-resonance pore imaging of nonsymmetric microscopic pore shapes

    NASA Astrophysics Data System (ADS)

    Hertel, Stefan Andreas; Wang, Xindi; Hosking, Peter; Simpson, M. Cather; Hunter, Mark; Galvosas, Petrik

    2015-07-01

    Imaging of the microstructure of porous media such as biological tissue or porous solids is of high interest in health science and technology, engineering and material science. Magnetic resonance pore imaging (MRPI) is a recent technique based on nuclear magnetic resonance (NMR) which allows us to acquire images of the average pore shape in a given sample. Here we provide details on the experimental design, challenges, and requirements of MRPI, including its calibration procedures. Utilizing a laser-machined phantom sample, we present images of microscopic pores with a hemiequilateral triangular shape even in the presence of NMR relaxation effects at the pore walls. We therefore show that MRPI is applicable to porous samples without a priori knowledge about their pore shape and symmetry. Furthermore, we introduce "MRPI mapping," which combines MRPI with conventional magnetic resonance imaging (MRI). This enables one to resolve microscopic pore sizes and shapes spatially, thus expanding the application of MRPI to samples with heterogeneous distributions of pores.

  16. Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents

    PubMed Central

    Aptekar, Jacob W.; Cassidy, Maja C.; Johnson, Alexander C.; Barton, Robert A.; Lee, Menyoung; Ogier, Alexander C.; Vo, Chinh; Anahtar, Melis N.; Ren, Yin; Bhatia, Sangeeta N.; Ramanathan, Chandrasekhar; Cory, David G.; Hill, Alison L.; Mair, Ross W.; Rosen, Matthew S.; Walsworth, Ronald L.

    2014-01-01

    Magnetic resonance imaging of hyperpolarized nuclei provides high image contrast with little or no background signal. To date, in-vivo applications of pre-hyperpolarized materials have been limited by relatively short nuclear spin relaxation times. Here, we investigate silicon nanoparticles as a new type of hyperpolarized magnetic resonance imaging agent. Nuclear spin relaxation times for a variety of Si nanoparticles are found to be remarkably long, ranging from many minutes to hours at room temperature, allowing hyperpolarized nanoparticles to be transported, administered, and imaged on practical time scales. Additionally, we demonstrate that Si nanoparticles can be surface functionalized using techniques common to other biologically targeted nanoparticle systems. These results suggest that Si nanoparticles can be used as a targetable, hyperpolarized magnetic resonance imaging agent with a large range of potential applications. PMID:19950973

  17. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    MedlinePlus

    ... cause a problem near a strong magnetic field. Electronic devices aren't permitted in the MRI room. ... child may be given headphones to listen to music or earplugs to block the noise, and will ...

  18. Magnetic Resonance Imaging (MRI): Dynamic Pelvic Floor

    MedlinePlus

    ... noninvasive test that uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  19. Human tooth and root canal morphology reconstruction using magnetic resonance imaging

    PubMed Central

    DRĂGAN, OANA CARMEN; FĂRCĂŞANU, ALEXANDRU ŞTEFAN; CÂMPIAN, RADU SEPTIMIU; TURCU, ROMULUS VALERIU FLAVIU

    2016-01-01

    Background and aims Visualization of the internal and external root canal morphology is very important for a successful endodontic treatment; however, it seems to be difficult considering the small size of the tooth and the complexity of the root canal system. Film-based or digital conventional radiographic techniques as well as cone beam computed tomography provide limited information on the dental pulp anatomy or have harmful effects. A new non-invasive diagnosis tool is magnetic resonance imaging, due to its ability of imaging both hard and soft tissues. The aim of this study was to demonstrate magnetic resonance imaging to be a useful tool for imaging the anatomic conditions of the external and internal root canal morphology for endodontic purposes. Methods The endodontic system of one freshly extracted wisdom tooth, chosen for its well-known anatomical variations, was mechanically shaped using a hybrid technique. After its preparation, the tooth was immersed into a recipient with saline solution and magnetic resonance imaged immediately. A Bruker Biospec magnetic resonance imaging scanner operated at 7.04 Tesla and based on Avance III radio frequency technology was used. InVesalius software was employed for the 3D reconstruction of the tooth scanned volume. Results The current ex-vivo experiment shows the accurate 3D volume rendered reconstruction of the internal and external morphology of a human extracted and endodontically treated tooth using a dataset of images acquired by magnetic resonance imaging. The external lingual and vestibular views of the tooth as well as the occlusal view of the pulp chamber, the access cavity, the distal canal opening on the pulp chamber floor, the coronal third of the root canals, the degree of root separation and the apical fusion of the two mesial roots, details of the apical region, root canal curvatures, furcal region and interradicular root grooves could be clearly bordered. Conclusions Magnetic resonance imaging offers 3

  20. Co-Funding for the Conference on Magnetic Resonance in Biological Systems

    SciTech Connect

    Alan McLaughlin, Ph.D., Director, Division of Applied Science & Technology, NIBIB, NIH

    2008-10-01

    The XXIst International Conference on Magnetic Resonance in Biological Systems (ICMRBS 2005), '60th anniversary of the discovery of Nuclear Magnetic Resonance,' was held between 16 and 21 January 2005 in Hyderabad, India. The meeting focused on a broad range of magnetic resonance methods as applied to studies of biological processes related to human health. The biennial ICMRBS has become the major venue for discussion of advances in nuclear and electron magnetic resonance (NMR & EMR/EPR) studies of the structure, dynamics, and chemical properties of important classes of biomolecules. Magnetic resonance has become an established tool in structural biology, and its special importance derives from its ability to provide atomic level information. It is becoming increasingly evident that the dynamic features of biomolecules, their intermolecular interactions, and accessible conformations in solution are data of key importance in understanding molecular recognition and function. NMR, which is already contributing to approximately 25% of the new structures being deposited with the Protein Data Bank, is destined to be a major player in the post genomic structure age with its emphasis on structure and function. In-vivo magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) results shed light on human metabolic processes and on the cellular ramifications of cancer, stroke, cardiovascular disease, and other pathologies. New methodologies in metabonomics may lead to development of new drugs and medical diagnosis. The ICMRBS is the one conference that brings together experts from high-resolution NMR, solid state NMR, EPR, in-vivo MRS and MRI, and developers of instrumentation, techniques, software, and databases. Symposia at this ICMRBS are designed to continue the fruitful cross-fertilization of ideas that has been so successful in driving the spectacular advances in this field. ICMRBS 2005 maintained the traditional format of poster sessions, and plenary