Contribution of brain imaging techniques: CT-scan and magnetic resonance imaging (MRI)

International Nuclear Information System (INIS)

Pasco-Papon, A.; Gourdier, A.L.; Papon, X.; Caron-Poitreau, C.

1996-01-01

In light of the current lack of consensus on the benefit of carotid artery surgery to treat asymptomatic carotid artery stenosis, the decision to operate on a patient depends on individual evaluation and characterization of risk factors on carotid artery stenosis greater than 70 %. The assessment of such risk factors is based especially on non-invasive brain imaging techniques.Computed tomography scanning (CT-scan) and magnetic resonance imaging (MRI) enable two types of stenosis to be differentiated, i.e. stenoses which are symptomatic and those that are radiologically proven versus those which are clinically and radiologically silent. CT-scan investigation (with and without injection of iodinated contrast media) still continues to be a common routine test in 1996 whenever a surgical revascularization procedure is planned. The presence of deep lacunar infarcts ipsilateral to the carotid artery stenosis generally evidence the reality of stenosis and thus are useful to the surgeon in establishing whether surgery is indicated. In the absence a consensus on indications for surgical management, the surgeon could use the CT-scan and MRI as medicolegal records which could be compared to a subsequent postoperative CT-scan in case of ischemic complications associated with the surgical procedure. Furthermore, recent cerebral ischemia as evidenced by filling with contrast material, will call for postponing treatment by a few weeks. Although conventional MRI is more contributive than brain CT-scan in terms of sensibility and specificity, its indications are narrower because of its limited availability and cost constraints. But, development of angio-MRI and functional imaging promise that its future is assured and even perhaps as the sole diagnostic method if its indications are expanded to include preoperative angiographic evaluation of atheromatous lesions of supra-aortic trunks. (authors). 37 refs

Magnetic resonance imaging in central nervous system tuberculosis

International Nuclear Information System (INIS)

Trivedi, Richa; Saksena, Sona; Gupta, Rakesh K

2009-01-01

Tuberculosis (TB) in any form is a devastating disease, which in its most severe form involves the central nervous system (CNS), with a high mortality and morbidity. Early diagnosis of CNS TB is necessary for appropriate treatment to reduce this morbidity and mortality. Routine diagnostic techniques involve culture and immunological tests of the tissue and biofluids, which are time-consuming and may delay definitive management. Noninvasive imaging modalities such as computed tomography (CT) scan and magnetic resonance imaging (MRI) are routinely used in the diagnosis of neurotuberculosis, with MRI offering greater inherent sensitivity and specificity than CT scan. In addition to conventional MRI imaging, magnetization transfer imaging, diffusion imaging, and proton magnetic resonance spectroscopy techniques are also being evaluated for better tissue characterization in CNS TB. The current article reviews the role of various MRI techniques in the diagnosis and management of CNS TB

Pattern of magnetic resonance imaging and magnetic resonance venography changes in cerebral venous sinus thrombosis

International Nuclear Information System (INIS)

Zafar, A.; Ali, Z.

2012-01-01

Background: Cerebral venous sinus thrombosis is a common but highly under-recognised condition, which is missed not only by general practitioners but also by neurologists. Computerised tomography (CT) or magnetic resonance imaging (MRI) of brain alone is not sufficient to diagnose this condition. Objective of this study was to explore the pattern of magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) changes in cerebral venous sinus thrombosis (CVST). Methods: This was a descriptive study in which 52 cases of cerebral venous sinus thrombosis with special emphasis on their MRI and MRV findings were included. The study was conducted in Neurology Unit, Lady Reading Hospital, Peshawar, Pakistan, from January 2010 to July 2011. All patients suffering from cerebral venous sinus thrombosis were included in the study. Multi-planar/multi-sequential, Tesla 1.5 MRI/MRV time of flight images were done in all cases where there was suspicion of cerebral venous sinus thrombosis. Results: Out of 52 patients with cerebral venous sinus thrombosis 41 (78.84%) were female and 11 (21.15%) were male. Mean age was 37+-5 years. Definite risk factors were found in 38 (73.076%) patients with pregnancy, use of oral contraceptives or puerperium being the most frequently found risk factor in 20 (73.076%) patients. Most common complaint was headache found in 41 (78.84%) patients, followed by focal neurological deficits, and altered mental status and seizures. Papilloedema was seen in 20 (38.46%) patients. The cerebral venous sinuses most frequently involved were transverse and sigmoid sinuses in 17 patients (32.69%) while superior sagittal sinus alone in 10 (19.23%) patients. Overall CT brain was normal in 30% and MRI brain in 23.07% patients; however, MRV of these patients revealed CVST. Conclusion: Imaging plays a primary role in the diagnosis of cerebral venous sinus thrombosis because the clinical picture of CVST is non-specific and highly variable. Thrombosis of

Magnetic resonance tomography of the temporo-mandibular joints

International Nuclear Information System (INIS)

Katzberg, R.W.; Burgener, F.A.

1986-01-01

79 patients aged 6 to 66 years (9 men and 70 women) with abnormalities of the TMJs were examined by magnetic resonance tomography (132 joints) and the results were compared with CT (16 joints) and resonance tomography showed forward luxation of the meniscus in 82 joints (62%). In 34 joints (26%) the meniscus spontaneously resumed normal position when the mouth was open, but in 48 joints (36%) the displacement was permanent. The accuracy of resonance tomography was equal to that of arthrography and superior to CT. It was particularly suitable for follow-up examination after surgery (23 cases) when invasive arthrography would be contraindicated or difficult. Because of the high resolution of the soft tissue components in the TMJ, resonance tomography should be able to diagnose inflammatory and degenerative changes in the meniscus and ligaments. (orig.)

Magnetic resonance imaging in psychiatry

International Nuclear Information System (INIS)

Mann, K.

1993-01-01

Diagnosis and research in psychiatry are increasingly availing themselves of magnetic resonance imaging (MRI). In comparison to computed tomography (CT), this offers the combined benefits of no exposure to radiation, high resolution, artefact-free display of structures near bone, and a sharp contrast between the grey and white brain matter, with freedom to select the section. With the exception of very anxious patients, MRI will gradually replace CT scans for a wide range of differential diagnostic investigations. Its superiority in systematic studies of psychiatric patients with discrete cerebral parenchyma lesions is already considered proven. This is illustrated on the basis of research into schizophrenia and alcoholism. (orig.) [de

Magnetic resonance annual 1986

International Nuclear Information System (INIS)

Kressel, H.Y.

1986-01-01

This book contains papers written on magnetic resonance during 1986. Topics include: musculosketetal magnetic resonance imaging; imaging of the spine; magnetic resonance chemical shift imaging; magnetic resonance imaging in the central nervous system; comparison to computed tomography; high resolution magnetic resonance imaging using surface coils; magnetic resonance imaging of the chest; magnetic resonance imaging of the breast; magnetic resonance imaging of the liver; magnetic resonance spectroscopy of neoplasms; blood flow effects in magnetic resonance imaging; and current and potential applications of clinical sodium magnetic resonance imaging

Magnetic resonance imaging in the cranio-cervical region

International Nuclear Information System (INIS)

Koschorek, F.; Jensen, H.P.; Terwey, B.

1987-01-01

Since the introduction of nuclear magnetic resonance imaging (NMR) in the neurosurgical and neurological diagnostic this new imaging modality has shown to be of high diagnostic value - especially in disease process of the cranio-vertebral junction. Other imaging moralities such as x-ray CT and myelography are of inferior quality as the images are degraded by bone artifacts and superposition of other structures. NMR can reveal many aspects of the cranio-vertebral region in a single examination without artifacts from surrounding structures. A further improvement of NMR is the introduction of para-magnetic agents, such as gadolinium-DTPA, as it increases the specifity by dynamic magnetic resonance imaging. The authors present a review of their clinical experience

Nuclear magnetic resonance tomography in Hallervorden-Spatz's syndrome

International Nuclear Information System (INIS)

Vogl, T.; Bauer, M.; Seiderer, M.; Rath, M.

1984-01-01

Two patients (mother and son) with Hallervorden-Spatz's syndrome were examined both via CT and Nuclear Magnetic Resonance (NMR), using different measuring modes. In the patient with progressing disease pathological findings were seen in the right and left putamen with CT and NMR. All examinations in the mother with a less progressive syndrome were without any result. Information obtained via NMR did not yield significantly more relevant data than computed tomography. (orig.) [de

The value of magnetic resonance imaging in the diagnosis of orbital floor fractures

International Nuclear Information System (INIS)

Freund, Michael; Haehnel, Stefan; Sartor, Klaus

2002-01-01

The value of MRI in the diagnosis of acute orbital floor fractures has not been clearly defined. We therefore compared MR findings with CT findings in patients with orbital trauma. In 30 patients with isolated orbital trauma both coronal CT and coronal MRI were used to examine the orbits and the adjacent paranasal sinuses. Visualization of anatomical landmarks, the kind and extent of traumatic lesions, as well as artifacts were scored. The scores were compared using the Wilcoxon matched-pairs signed-rank test. Interexamination agreement between the two methods was calculated using a kappa analysis. All examinations had diagnostic quality: 30 fractures of the orbital floor (9 right and 21 left orbital floor fractures) were identified. In addition, CT showed fractures of the medial orbital wall in 19 patients (63.3%), of the lateral wall in 10 patients (33.3%), of the zygomatic arch in 2 patients (6.7%), and of the maxillary sinus in 4 patients (13.3%). Soft tissue herniation was shown in 13 patients (inferior rectus muscle twice, orbital fat in 11 cases). Magnetic resonance imaging demonstrated soft tissue herniation in 21 patients: muscle in 4, orbital fat in 17 cases. Magnetic resonance imaging is able to demonstrate orbital floor fractures as sensitively as CT, but CT is superior to MRI in showing small and associated fractures; therefore, CT remains in orbital fractures the imaging modality of choice. Magnetic resonance imaging is superior to CT in showing soft tissue herniations; therefore, MRI may have a role as an adjunct to CT if soft tissue entrapment remains unclear. (orig.)

Urothelial carcinoma in a pyelocaliceal diverticulum discovered by magnetic resonance urography[

Energy Technology Data Exchange (ETDEWEB)

Akatsuka, Jun; Suzuki, Yasutomo; Hamasaki, Tsutomu; Kimura, Go; Kondo, Yukihiro, E-mail: s00-001@nms.ac.jp [Departments of Urology, Nippon Medical School, Bunkyo-ku, Tokyo (Japan)

2014-03-15

Neither computed tomography (CT) nor intravenous pyelography (IVP) alone can diagnose tumors of renal pelvic diverticula, but magnetic resonance urography (MRU) can obtain accurate preoperative information. (author)

Urothelial carcinoma in a pyelocaliceal diverticulum discovered by magnetic resonance urography

Directory of Open Access Journals (Sweden)

Jun Akatsuka

2014-04-01

Full Text Available Neither computed tomography (CT nor intravenous pyelography (IVP alone can diagnose tumors of renal pelvic diverticula, but magnetic resonance urography (MRU can obtain accurate preoperative information.

Magnetic-resonance-guided biopsy of focal liver lesions

Energy Technology Data Exchange (ETDEWEB)

Smith, Ethan A. [University of Michigan Health System, Section of Pediatric Radiology, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); Grove, Jason J. [University of Michigan Health System, Division of Interventional Radiology, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); Der Spek, Abraham F.L.V. [University of Michigan Health System, Department of Anesthesiology, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States); Jarboe, Marcus D. [University of Michigan Health System, Division of Interventional Radiology, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); University of Michigan Health System, Section of Pediatric Surgery, C.S. Mott Children' s Hospital, Department of Surgery, Ann Arbor, MI (United States)

2017-05-15

Image-guided biopsy techniques are widely used in clinical practice. Commonly used methods employ either ultrasound (US) or computed tomography (CT) for image guidance. In certain patients, US or CT guidance may be suboptimal, or even impossible, because of artifacts, suboptimal lesion visualization, or both. We recently began performing magnetic resonance (MR)-guided biopsy of focal liver lesions in select pediatric patients with lesions that are not well visualized by US or CT. This report describes our experience performing MR-guided biopsy of focal liver lesions, with case examples to illustrate innovative techniques and novel aspects of these procedures. (orig.)

Contemporary imaging: Magnetic resonance imaging, computed tomography, and interventional radiology

International Nuclear Information System (INIS)

Goldberg, H.I.; Higgins, C.; Ring, E.J.

1985-01-01

In addition to discussing the most recent advances in magnetic resonance imaging (MRI), computerized tomography (CT), and the vast array of interventional procedures, this book explores the appropriate clinical applications of each of these important modalities

Magnetic resonance imaging in Pelizaeus-Merzbacher disease

International Nuclear Information System (INIS)

Journel, H.; Roussey, M.; Allaire, C.; Le Marec, B.; Gandon, Y.; Carsin, M.

1987-01-01

Pelizaeus-Merzbacher's disease is a progressive encephalopathy with demyelination of the cerebral white matter. The diagnosis cannot be made on clinical or biological grounds: pathological investigation is necessary to confirm tigroid demyelination. CT scanning failure to visualize this type of anomaly but detection is now possible with the advent of magnetic resonance imaging (MRI). The authors studied the case of a boy who, at the age of 8 presented with symptoms characeristic of the disease, rotatory nystagmus, progressive encephalopathy, and inherited X-linked recessive traits. Magnetic resonance imaging revealed a high signal in the supra-tentorial white matter and the usual contrast was inverted. The authors believe that MRI can make an important contribution to the diagnosis of the disease. (orig.)

Magnetic resonance in hematological diseases. Imaging of bone marrow

DEFF Research Database (Denmark)

Jensen, K.E.

1995-01-01

Magnetic resonance imaging (MRI) is a highly sensitive alternative to plain radiography, CT, and radionuclide studies for the imaging of normal and abnormal bone marrow. The cellularity and the corresponding fat/water ratio within the bone marrow show clear changes in haematological diseases. Thi...

Pictorial review: magnetic resonance imaging of colonic diverticulitis

International Nuclear Information System (INIS)

Buckley, Orla; Geoghegan, Tony; McAuley, Grainne; Persaud, Thara; Khosa, Faisal; Torreggiani, William C.

2007-01-01

Magnetic resonance imaging (MRI) is rapidly emerging as a useful imaging modality for the evaluation of the gastrointestinal tract. Increasingly rapid sequences and improving hardware have significantly improved the visualisation of diseases of the colon. MRI has a major advantage over CT in that there is no ionising radiation. In our institution, MRI has increasingly been used as a complimentary imaging modality to CT in the diagnosis and evaluation of diverticulitis and its complications. In this review article, we illustrate the emerging role of MRI in the diagnosis and evaluation of colonic diverticulitis. (orig.)

Magnetic resonance imaging of hypothalamic hamartoma

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Kanazawa, Junichi; Uozumi, Tohru; Sakoda, Katsuaki; Yamanaka, Masami; Kihara, Mikio; Nishi, Yoshikazu; Kagawa, Yoshihiro; Kajima, Toshio.

1988-05-01

Magnetic resonance (MR) findings of two patients with a hypothalamic hamartoma are discussed. The two girls showed clinical symptoms and endocrinological signs of precocious puberty. MR imaging was of diagnostic value superior to that of CT in the demonstration of the characteristic location of this tumor and relationships to the neighboring structures because of its multi-dimensional utility. Although it has been reported that CT showed this lesion as isodense to the grey matter with and without injection of contrast medium, MR imaging depicted the lesion as a high signal intensity area on T2-weighted images in both patients. MR imaging is a useful method for the evaluation of the hypothalamic hamartoma.

Radiologic Diagnosis of Spondylodiscitis, Role of Magnetic Resonance

Science.gov (United States)

Ramadani, Naser; Dedushi, Kreshnike; Kabashi, Serbeze; Mucaj, Sefedin

2017-01-01

Introduction: Study aim is to report the Magnetic Resonance Imaging (MRI) features of acute and chronic spontaneous spondylodiscitis. Case report: 57 year old female, complaining of a fever and longstanding cervical pain worsened during physical therapy. Methods: MR images were acquired using superconductive magnet 1.5 T, with the following sequences: sagittal PD and T2 TSE, sagittal T1 SE, axial PD and T2 TSE (lumbar spine), axial T2 GRE (cervical spine). Axial and sagittal T1 SE after administration of (gadolinium DTPA). Examination was reviewed by three radiologists and compared to CT findings. Results: Patient reported cervical pain associated with fever and minimal weight loss. Blood tests were normal except hyperglycemia (DM tip II). X Ray: vertebral destruction localized at C-4 and C-5: NECT: destruction of the C-4/C-5 vertebral bodies (ventral part). MRI: Low signal of the bone marrow on T1l images, which enhanced after Gd-DTPA administration and became intermediate or high on T2 images. The steady high signal intensity of the disk on T2 images and enhancement on T1 images is typical for an acute inflammatory process. Bone Scintigrafi results: Bone changes suspicious for metastasis. Whole body CT results: apart from spine, no other significant changes. Conclusion: MRI is the most sensitive technique for the diagnosis of spondylodiscitis in the acute phase and comparable to CT regarding chronial stage of the disease. The present imagining essay os aimed at showing the main magnetic resonance imaging findings of tuberculous discitis. PMID:28484299

Radiologic Diagnosis of Spondylodiscitis, Role of Magnetic Resonance.

Science.gov (United States)

Ramadani, Naser; Dedushi, Kreshnike; Kabashi, Serbeze; Mucaj, Sefedin

2017-03-01

Study aim is to report the Magnetic Resonance Imaging (MRI) features of acute and chronic spontaneous spondylodiscitis. 57 year old female, complaining of a fever and longstanding cervical pain worsened during physical therapy. MR images were acquired using superconductive magnet 1.5 T, with the following sequences: sagittal PD and T2 TSE, sagittal T1 SE, axial PD and T2 TSE (lumbar spine), axial T2 GRE (cervical spine). Axial and sagittal T1 SE after administration of (gadolinium DTPA). Examination was reviewed by three radiologists and compared to CT findings. Patient reported cervical pain associated with fever and minimal weight loss. Blood tests were normal except hyperglycemia (DM tip II). X Ray: vertebral destruction localized at C-4 and C-5: NECT: destruction of the C-4/C-5 vertebral bodies (ventral part). MRI: Low signal of the bone marrow on T1l images, which enhanced after Gd-DTPA administration and became intermediate or high on T2 images. The steady high signal intensity of the disk on T2 images and enhancement on T1 images is typical for an acute inflammatory process. Bone Scintigrafi results: Bone changes suspicious for metastasis. Whole body CT results: apart from spine, no other significant changes. MRI is the most sensitive technique for the diagnosis of spondylodiscitis in the acute phase and comparable to CT regarding chronial stage of the disease. The present imagining essay os aimed at showing the main magnetic resonance imaging findings of tuberculous discitis.

Magnetic resonance imaging in neurologic diseases

International Nuclear Information System (INIS)

Chang, Kee Hyun; Han, Man Chung; Wan, Chu Wan; Myung, Ho Jin; Choi, Kil Soo; Ahn, Chang Beom; Oh, Chang Hyun; Cho, Zang Hee

1985-01-01

Magnetic resonance (MR) imaging with 0.15 Tesla resistive magnet developed by Korea Advanced Institute of Science were performed in 27 patients with various neurologic diseases and compared with x-ray computed tomography (CT). The purpose of the paper is to evaluate the image quality, the diagnostic value and limitation, and the optimal pulse sequence of MR imagings with a resistive magnet. The MR images were obtained by using a variety of pulse sequence with spin echo technique including saturation recovery. T2-weighted spin echo, and/or inversion recovery with various pulse repetition (TR) and echo delay (TE) times. The MR imaging demonstrated the capability of detecting the lesions shown on CT in al cases and also detected an additional finding in one case (multiple sclerosis) which was not seen on CT. The MR imaging appeared to be more useful than CT in the evaluation of syringomyelia of spinal cord and white matter disease, while it failed to demonstrated small calcific lesion or inflammatory nodule (less than 1 cm) shown on CT and has shown somewhat poor contrast resolution in the case of meingloma. The spatial resolution of saturation recovery images was similar or superior to CT, whereas the contrast resolution of saturation recovery was inferior to CT. While the saturation recovery images have shown false negative findings in 5 patients (19%), the inversion recovery and T2-weighted spin echo have shown consistently positive findings. The inversive recovery and T2-weighted spin echo images demonstrated better contrast discrimination between normal and pathologic conditions than the saturation recovery images, but somewhat poorer spatial resolution. Authors suggest that the MR images of both the saturation recovery with 300/30 and T2-weighted spin echo with 1000/90 be used as a routine procedure and additional inversion recovery of 1300/300/30 sequence as a option if white matter disease is suspected

Assessing the Dosimetric Accuracy of Magnetic Resonance-Generated Synthetic CT Images for Focal Brain VMAT Radiation Therapy

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Paradis, Eric, E-mail: eparadis@umich.edu [Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan (United States); Cao, Yue [Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan (United States); Department of Biomedical Engineering, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan (United States); Lawrence, Theodore S.; Tsien, Christina; Feng, Mary; Vineberg, Karen; Balter, James M. [Department of Radiation Oncology, University of Michigan Hospital and Health Systems, Ann Arbor, Michigan (United States)

2015-12-01

Purpose: The purpose of this study was to assess the dosimetric accuracy of synthetic CT (MRCT) volumes generated from magnetic resonance imaging (MRI) data for focal brain radiation therapy. Methods and Materials: A study was conducted in 12 patients with gliomas who underwent both MR and CT imaging as part of their simulation for external beam treatment planning. MRCT volumes were generated from MR images. Patients' clinical treatment planning directives were used to create 12 individual volumetric modulated arc therapy (VMAT) plans, which were then optimized 10 times on each of their respective CT and MRCT-derived electron density maps. Dose metrics derived from optimization criteria, as well as monitor units and gamma analyses, were evaluated to quantify differences between the imaging modalities. Results: Mean differences between planning target volume (PTV) doses on MRCT and CT plans across all patients were 0.0% (range: −0.1 to 0.2%) for D{sub 95%}; 0.0% (−0.7 to 0.6%) for D{sub 5%}; and −0.2% (−1.0 to 0.2%) for D{sub max}. MRCT plans showed no significant changes in monitor units (−0.4%) compared to CT plans. Organs at risk (OARs) had average D{sub max} differences of 0.0 Gy (−2.2 to 1.9 Gy) over 85 structures across all 12 patients, with no significant differences when calculated doses approached planning constraints. Conclusions: Focal brain VMAT plans optimized on MRCT images show excellent dosimetric agreement with standard CT-optimized plans. PTVs show equivalent coverage, and OARs do not show any overdose. These results indicate that MRI-derived synthetic CT volumes can be used to support treatment planning of most patients treated for intracranial lesions.

Value of computed tomography and magnetic resonance imaging in diagnosis of central nervous system

International Nuclear Information System (INIS)

Walecka, I.; Sicinska, J.; Szymanska, E.; Rudnicka, L.; Furmanek, M.; Walecki, J.; Olszewska, M.; Rudnicka, L.; Walecki, J.

2006-01-01

Systemic sclerosis is an autoimmune connective tissue disease characterized by vascular abnormalities and fibrotic changes in skin and internal organs. The aim of the study was to investigate involvement of the central nervous system in systemic sclerosis and the value of computed tomography (CT) and magnetic resonance imaging (MRI) in evaluation of central nervous system involvement in systemic sclerosis. 26 patients with neuropsychiatric symptoms in the course of systemic sclerosis were investigated for central nervous system abnormalities by computed tomography (CT) and magnetic resonance imaging (MRI). Among these 26 symptomatic patients lesions in brain MRI and CT examinations were present in 54% and in 50% patients respectively. Most common findings (in 46% of all patients), were symptoms of cortical and subcortical atrophy, seen in both, MRI and CT. Single and multiple focal lesions, predominantly in the white matter, were detected by MRI significantly more frequently as compared to CT (62% and 15% patients respectively). These data indicate that brain involvement is common in patients with severe systemic sclerosis. MRI shows significantly higher than CT sensitivity in detection focal brain lesions in these patients. (author)

Magnetic resonance imaging of the brain in systemic lupus erythematosus

Energy Technology Data Exchange (ETDEWEB)

Kodama, Kazuhiro; Sato, Toshio; Koseki, Keijiro

1987-09-01

Cranial magnetic resonance imaging (MRI) was performed in five patients with systemic lupus erythematosus manifested by neurologic symptoms. The results were compared with those of the concurrent X-ray computed tomography (CT). CT scans showed slight cerebral atrophy in four patients, including one with coexisting enlargement of the lateral ventricle. In three of them, MRI scans showed additional abnormal appearance, possibly reflecting cerebral infarction and reversible changes in water content of cerebral tissues. The findings of MRI and CT in a small series of patients was disappointing in the explanation of the occurrence of neurologic symptoms. (Namekawa, K.).

Magnetic resonance imaging of the brain in systemic lupus erythematosus

International Nuclear Information System (INIS)

Kodama, Kazuhiro; Sato, Toshio; Koseki, Keijiro

1987-01-01

Cranial magnetic resonance imaging (MRI) was performed in five patients with systemic lupus erythematosus manifested by neurologic symptoms. The results were compared with those of the concurrent X-ray computed tomography (CT). CT scans showed slight cerebral atrophy in four patients, including one with coexisting enlargement of the lateral ventricle. In three of them, MRI scans showed additional abnormal appearance, possibly reflecting cerebral infarction and reversible changes in water content of cerebral tissues. The findings of MRI and CT in a small series of patients was disappointing in the explanation of the occurrence of neurologic symptoms. (Namekawa, K.)

MRI (Magnetic Resonance Imaging)

Science.gov (United States)

... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

Bifurcation magnetic resonance in films magnetized along hard magnetization axis

Energy Technology Data Exchange (ETDEWEB)

Vasilevskaya, Tatiana M., E-mail: t_vasilevs@mail.ru [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation); Sementsov, Dmitriy I.; Shutyi, Anatoliy M. [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation)

2012-09-15

We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: Black-Right-Pointing-Pointer An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. Black-Right-Pointing-Pointer Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. Black-Right-Pointing-Pointer Both regular and chaotic precession modes are realized within bifurcation resonance range. Black-Right-Pointing-Pointer Appearance of dynamic bistability is typical for bifurcation resonance.

Bifurcation magnetic resonance in films magnetized along hard magnetization axis

International Nuclear Information System (INIS)

Vasilevskaya, Tatiana M.; Sementsov, Dmitriy I.; Shutyi, Anatoliy M.

2012-01-01

We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: ► An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. ► Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. ► Both regular and chaotic precession modes are realized within bifurcation resonance range. ► Appearance of dynamic bistability is typical for bifurcation resonance.

Focal fatty infiltration of the liver: demonstration by magnetic resonance imaging

International Nuclear Information System (INIS)

Wenker, J.C.; Baker, M.K.; Ellis, J.H.; Glant, M.D.

1984-01-01

Focal fatty infiltration of the liver is a recently recognized yet poorly understood entity, which has become more apparent since the onset of widespread computed tomographic (CT) scanning. Recent reports have suggested that magnetic resonance imaging (MRI) may not be sensitive in the evaluation of diffuse fatty liver. A case is presented in which MRI was as sensitive as CT and sonography in the demonstration of focal fatty change within the liver

Magnetic resonance tomography (MRT) for lesions of the temporal lobes

International Nuclear Information System (INIS)

Schoerner, W.; Felix, R.; Meencke, H.J.; Freie Univ. Berlin; Freie Univ. Berlin

1985-01-01

A comparative study between magnetic resonance tomography (MRT) and CT was carried out in 16 patients with temporal lobe epilepsy. The MRT studies were performed on a 0.35 T Magnetom with T.1 modes in a coronal plane. MRT proved to the superior to CT. CT demonstrated a discrete temporal lobe lesion in three patients and MRT in four patients. In addition, unilateral atrophy of the temporal lobe was demonstrated by MRT in six cases; these could not be diagnosed by CT. The lack of artifacts near the skull base, the possibility of producing coronal sections and the excellent tissue differential of MRT provide the basis for improved diagnosis of lesions in the temporal lobes. (orig.) [de

Nuclear magnetic resonance

International Nuclear Information System (INIS)

Ethier, R.; Melanson, D.; Peters, T.M.

1983-01-01

Ten years following computerized tomography, a new technique called nuclear magnetic resonance revolutionizes the field of diagnostic imaging. A major advantage of nuclear magnetic resonance is that the danger of radiation is non-existent as compared to computerized tomography. When parts of the human body are subject to radio-frequencies while in a fixed magnetic field, its most detailed structures are revealed. The quality of images, the applications, as well as the indications are forever increasing. Images obtained at the level of the brain and spinal cord through nuclear magnetic resonance supercede those obtained through computerized tomography. Hence, it is most likely that myelography, along with pneumoencephalography will be eliminated as a diagnostic means. It is without a doubt that nuclear magnetic resonance is tomorrow's computerized tomography [fr

Computed Tomography and Magnetic Resonance Imaging Features of the Temporomandibular Joint in Two Normal Camels

Directory of Open Access Journals (Sweden)

Alberto Arencibia

2012-01-01

Full Text Available Computed tomography (CT and magnetic resonance (MR image features of the temporomandibular joint (TMJ and associated structures in two mature dromedary camels were obtained with a third-generation equipment CT and a superconducting magnet RM at 1.5 Tesla. Images were acquired in sagittal and transverse planes. Medical imaging processing with imaging software was applied to obtain postprocessing CT and MR images. Relevant anatomic structures were identified and labelled. The resulting images provided excellent anatomic detail of the TMJ and associated structures. Annotated CT and MR images from this study are intended as an anatomical reference useful in the interpretation for clinical CT and MR imaging studies of the TMJ of the dromedary camels.

The use of magnetic resonance tomography in gastrointestinal diagnostics

International Nuclear Information System (INIS)

Geitung, Jonn Terje

2000-01-01

Background: Magnetic resonance imaging (MRI) is a promising method for examination of the gastrointestinal tract. In this article we present the present status and potential of MRI. Material and method: The review is based on personal experience and selected published, international papers. Results: Magnetic resonance cholangio-pancreatography (MRCP) and MRI of the liver are well documented examinations which are widely performed. These examinations partly replace existing modalities such as CT and ERCP and represent additional possibilities for examining this anatomic area. MRI is not as yet accepted as the standard examination of the pancreas, but it is regarded as comparable to CT. The adrenals may be examined even more accurately with MRI than with CT. MRI examinations of the oesophagus and gastric ventricle seem promising, but it should be said that they are in an early and not well document phase. MRI of the small and large bowels is not common. With the exception of preoperative staging of rectal cancers, it is still experimental. MR angiography, functional MRI studies and perfusion studies are not yet common in abdominal diseases. We may, however, believe that they will become important diagnostic tools. Interpretation: MRI is rapidly increasing its share of gastrointestinal imaging examinations. This is mainly due to the increased speed of newer machines. The diagnostic quality has improved and will improve more. It is thus likely that MRI will, in a large amount of abdominal imaging, replace CT and to some extent other diagnostic modalities. It is, however, not possible to replace CT for emergencies and we will probably look forward to more and better imaging with more diagnostic modalities in the future

Correlative neuroanatomy of computed tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Groot, J.

1984-01-01

Since the development of computed tomography (CT) more than a decade ago, still another form of imaging has become available that provides displays of normal and abnormal human structures. Magnetic resonance imaging is given complete coverage in this book. It describes both CT and MR anatomy that explains basic principles and the current status of imaging the brain and spine. The author uses three-dimensional concepts to provide the reader with a simple means to compare the main structures of the brain, skull and spine. Combining normal, gross neuroanatomic illustrations with CT and MR images of normal and abnormal conditions, the book provides diagnostic guidance. Drawings, photographs and radiologic images are used to help

Magnetic resonance imaging in complex partial seizures

International Nuclear Information System (INIS)

Furune, Sunao; Negoro, Tamiko; Maehara, Mitsuo; Nomura, Kazushi; Miura, Kiyokuni; Takahashi, Izumi; Watanabe, Kazuyoshi

1989-01-01

Magnetic resonance imaging (MRI) and computed tomography (CT) were performed on 45 patients with intractable complex partial seizures. MRI was performed with a superconducting whole-body scanner operating at 0.5 tesla (T) and 1.5 T. In patients with temporal lobe epilepsy, 8 of 24 patients had abnormal CT, but 16 or 24 patients showed abnormal MRI. 1.5 T MRI detected more abnormality than 0.5 T MRI when CT was normal. In patients with frontal lobe epilepsy, 5 of 7 patients had normal CT and MRI. In 2 other patients, MRI demonstrated an arachnoid cyst and increased signal intensity area on the T2-weighted images which were not detected by CT. In patients with occipital lobe epilepsy, 5 of 6 patients show abnormal CT and MRI. In patients with tuberous sclerosis, MRI revealed some increased signal intensity areas on the T2-weighted images in the occipital and temporal lobe, which were not detected by CT. Most surface EEG foci corresponded with the side of MRI abnormality. These data indicate that MRI is more informative than CT in complex partial seizures. MRI is the imaging technique of choice in the diagnosis of complex partial seizures. (author)

Magnetic resonance imaging apparatus

International Nuclear Information System (INIS)

Ehnholm, G.J.

1991-01-01

This patent describes an electron spin resonance enhanced magnetic resonance (MR) imaging (ESREMRI) apparatus able to generate a primary magnetic field during periods of nuclear spin transition excitation and magnetic resonance signal detection. This allows the generation of ESREMRI images of a subject. A primary magnetic field of a second and higher value generated during periods of nuclear spin transition excitation and magnetic resonance signal detection can be used to generate conventional MR images of a subject. The ESREMRI and native MR images so generated may be combined, (or superimposed). (author)

The OMERACT-RAMRIS Rheumatoid Arthritis Magnetic Resonance Imaging Joint Space Narrowing Score

DEFF Research Database (Denmark)

Møller Døhn, Uffe; Conaghan, Philip G; Eshed, Iris

2014-01-01

To test the intrareader and interreader reliability of assessment of joint space narrowing (JSN) in rheumatoid arthritis (RA) wrist and metacarpophalangeal (MCP) joints on magnetic resonance imaging (MRI) and computed tomography (CT) using the newly proposed OMERACT-RAMRIS JSN scoring method...

Cerebral fat embolism: magnetic resonance study

International Nuclear Information System (INIS)

Guedea, A.; Barrena, R.; Guelbenzu, S.; Tejada, A.

1998-01-01

We report the case of 26-year-old man who presented clinical evidence of fat embolism following a traffic accident. Although computed tomography (CT) of the brain showed no abnormalities, magnetic resonance imaging (MRI) disclosed several scattered points of high intensity on T2-weighted and proton density (PD) images, with complete resolution of the lesions on follow-up scan. MRI is considered more sensitive than computed tomography in detecting these lesions, and may be useful for their diagnosis, correlating well with the clinical course. (Author) 10 refs

Development of Nuclear Magnetic Resonance Imaging/spectroscopy for improved petroleum recovery. Final report

Energy Technology Data Exchange (ETDEWEB)

Barrufet, M.A.; Flumerfelt, F.W.; Walsh, M.P.; Watson, A.T.

1994-04-01

The overall objectives of this program are to develop and apply Nuclear Magnetic Resonance Imaging (NMRI) and CT X-Ray Scanning methods for determining rock, fluid, and petrophysical properties and for fundamental studies of multiphase flow behavior in porous media. Specific objectives are divided into four subtasks: (1) development of NMRI and CT scanning for the determination of rock-fluid and petrophysical properties; (2) development of NMRI and CT scanning for characterizing conventional multiphase displacement processes; (3) development of NMR and CT scanning for characterizing dispersed phase processes; and (4) miscible displacement studies.

Magnetic resonance of phase transitions

CERN Document Server

Owens, Frank J; Farach, Horacio A

1979-01-01

Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

Energy Technology Data Exchange (ETDEWEB)

Busch, S.; Johnson, T.R.C.; Wintersperger, B.J.; Minaifar, N.; Bhargava, A.; Rist, C.; Reiser, M.F.; Becker, C.; Nikolaou, K. [University of Munich, Department of Clinical Radiology, Munich (Germany)

2008-03-15

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 {+-} 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 {+-} 41.9 ml and 54.9 {+-} 29.6 ml, respectively, compared with 132.1 {+-} 40.8 ml EDV and 57.6 {+-} 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 {+-} 12.4% in DSCT and 57.9 {+-} 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

International Nuclear Information System (INIS)

Busch, S.; Johnson, T.R.C.; Wintersperger, B.J.; Minaifar, N.; Bhargava, A.; Rist, C.; Reiser, M.F.; Becker, C.; Nikolaou, K.

2008-01-01

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 ± 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 ± 41.9 ml and 54.9 ± 29.6 ml, respectively, compared with 132.1 ± 40.8 ml EDV and 57.6 ± 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 ± 12.4% in DSCT and 57.9 ± 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... a relatively short time, especially when compared to magnetic resonance imaging (MRI). CT scanning is painless, noninvasive and ... the extent of soft tissue of the tumor, magnetic resonance imaging (MRI) may be helpful. A person who ...

Imaging prostate cancer: an update on positron emission tomography and magnetic resonance imaging

DEFF Research Database (Denmark)

Bouchelouche, Kirsten; Turkbey, Baris; Choyke, Peter

2010-01-01

, and molecular imaging information. Developments in imaging technologies, specifically magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT), have improved the detection rate of prostate cancer. MRI has improved lesion detection and local staging. Furthermore, MRI...

Magnetic resonance imaging

International Nuclear Information System (INIS)

Anon.

1988-01-01

Magnetic resonance imaging (MRI) is a new and innovative technique that affords anatomic images in multiple planes and that may provide information about tissue characterization. The magnetic resonance images are obtained by placing the patient or the area of interest within a powerful, highly uniform, static magnetic field. Magnetized protons (hydrogen nuclei) within the patient align like small magnets in this field. Radiofrequency pulses are then used to create an oscillating magnetic field perpendicular to the main field. Magnetic resonance images differ from those produced by x-rays: the latter are associated with absorption of x-ray energy while magnetic resonance images are based on proton density and proton relaxation dynamics. Proton characteristics vary according to the tissue under examination and reflect its physical and chemical properties. To resolve issues regarding safety and efficacy, the Warren Grant Magnuson Clinical Center and the Office of Medical Applications of Research of the National Institutes of Health (NIH) convened a consensus conference about MRI Oct 26 through 28, 1987. At the NIH, the Consensus Development Conference brings together investigators in the biomedical sciences, clinical investigators, practicing physicians, and consumer and special interest groups to make a scientific assessment of technologies, including drugs, devices, and procedures, and to seek agreement on their safety and effectiveness

Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography

OpenAIRE

Tateyama, Akihiro; Fukukura, Yoshihiko; Takumi, Koji; Shindo, Toshikazu; Kumagae, Yuichi; Kamimura, Kiyohisa; Nakajo, Masayuki

2012-01-01

AIM: To clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT).

Pancreatic gross tumor volume contouring on computed tomography (CT) compared with magnetic resonance imaging (MRI): Results of an international contouring conference.

Science.gov (United States)

Hall, William A; Heerkens, Hanne D; Paulson, Eric S; Meijer, Gert J; Kotte, Alexis N; Knechtges, Paul; Parikh, Parag J; Bassetti, Michael F; Lee, Percy; Aitken, Katharine L; Palta, Manisha; Myrehaug, Sten; Koay, Eugene J; Portelance, Lorraine; Ben-Josef, Edgar; Erickson, Beth A

Accurate identification of the gross tumor volume (GTV) in pancreatic adenocarcinoma is challenging. We sought to understand differences in GTV delineation using pancreatic computed tomography (CT) compared with magnetic resonance imaging (MRI). Twelve attending radiation oncologists were convened for an international contouring symposium. All participants had a clinical and research interest in pancreatic adenocarcinoma. CT and MRI scans from 3 pancreatic cases were used for contouring. CT and MRI GTVs were analyzed and compared. Interobserver variability was compared using Dice's similarity coefficient (DSC), Hausdorff distances, and Jaccard indices. Mann-Whitney tests were used to check for significant differences. Consensus contours on CT and MRI scans and constructed count maps were used to visualize the agreement. Agreement regarding the optimal method to determine GTV definition using MRI was reached. Six contour sets (3 from CT and 3 from MRI) were obtained and compared for each observer, totaling 72 contour sets. The mean volume of contours on CT was significantly larger at 57.48 mL compared with a mean of 45.76 mL on MRI, P = .011. The standard deviation obtained from the CT contours was significantly larger than the standard deviation from the MRI contours (P = .027). The mean DSC was 0.73 for the CT and 0.72 for the MRI (P = .889). The conformity index measurement was similar for CT and MRI (P = .58). Count maps were created to highlight differences in the contours from CT and MRI. Using MRI as a primary image set to define a pancreatic adenocarcinoma GTV resulted in smaller contours compared with CT. No differences in DSC or the conformity index were seen between MRI and CT. A stepwise method is recommended as an approach to contour a pancreatic GTV using MRI. Copyright © 2017 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

History of the development of magnetic resonance imaging

International Nuclear Information System (INIS)

Murase, Kenya

2007-01-01

Nuclear magnetic resonance (NMR) has been a common tool for physicists and chemists to probe molecular structures since the phenomenon of NMR was discovered in 1946. The development of X-ray CT in 1973 played an important role in stimulating interest in NMR as an imaging tool, resulting in the birth of magnetic resonance imaging (MRI). Since its invention in the early 1970s, the development of MRI has been among the most active and exciting areas in science, technology, and medicine. Over the past twenty years, MRI has become one of the most important imaging modalities available to clinical medicine. In addition to its role as a routine imaging technique with a growing range of clinical applications, the pace of development in MRI methodology remains rapid, and new ideas with significant potential emerge on a regular basis. This article presents a brief history of the development of MRI. (author)

Magnetic resonance imaging of the visual pathway - anatomical and technical considerations

International Nuclear Information System (INIS)

Sosnowski, P.; Paprzycki, W.

1993-01-01

Magnetic resonance tomography creates possibility of imaging the whole visual pathway and is superior to CT. Plenitude of MR techniques can sometimes be the reason of unnecessary prolongation of the examination. This study tries to evaluate usefulness of different MR techniques and planes for optimal imaging of consecutive sections of visual pathway. (author)

Pediatric magnetic resonance imaging

International Nuclear Information System (INIS)

Cohen, M.D.

1986-01-01

This book defines the current clinical potential of magnetic resonance imaging and focuses on direct clinical work with pediatric patients. A section dealing with the physics of magnetic resonance imaging provides an introduction to enable clinicians to utilize the machine and interpret the images. Magnetic resonance imaging is presented as an appropriate imaging modality for pediatric patients utilizing no radiation

Advances in magnetic resonance 10

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.

Magnetic resonance imaging in psychiatry. Kernspintomographie in der Psychiatrie

Energy Technology Data Exchange (ETDEWEB)

Mann, K. (Psychiatrische Universitaetsklinik, Tuebingen (Germany))

1993-08-13

Diagnosis and research in psychiatry are increasingly availing themselves of magnetic resonance imaging (MRI). In comparison to computed tomography (CT), this offers the combined benefits of no exposure to radiation, high resolution, artefact-free display of structures near bone, and a sharp contrast between the grey and white brain matter, with freedom to select the section. With the exception of very anxious patients, MRI will gradually replace CT scans for a wide range of differential diagnostic investigations. Its superiority in systematic studies of psychiatric patients with discrete cerebral parenchyma lesions is already considered proven. This is illustrated on the basis of research into schizophrenia and alcoholism. (orig.)

Magnetic resonance imaging in pediatric neurological disease

International Nuclear Information System (INIS)

Tsukiyama, Takashi; Nishimoto, Hiroshi; Fujioka, Mutsuhisa; Aihara, Toshinori; Tanaka, Osamu.

1986-01-01

In this paper, we summarize our initial experience with Magnetic Resonance Imaging(MRI) in the evaluation of pediatric neurological disease. 17 children between the ages of 2 month and 8.5 year have been examined with MRI. All subjects tolerated the MRI procedure well, although sedation was necessary for young children. Result as follows : (1) MRI does not utilize ionising radiation to produce an image. (2) MRI images more clearly demonstrate cerebral gray and white matter than X-ray CT. (3) Compared with X-ray CT, MRI proved to be advantageous in detection and characterization of the pathology, especially when the abnormality was located along the posterior fossa and spinal canal. It is suggested that these nature of MRI makes it the ideal diagnostic method for children. (author)

Magnetic resonance imaging of nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Naito, Yasushi; Tamaki, Susumu; Kurata, Kyosuke; Honjo, Iwao; Nishimura, Kazumasa; Nakano, Yoshihisa

1987-01-01

Magnetic resonance imaging (MRI) of the nasopharynx, the eustachian tube and the middle ear was performed in nine patients with nasopharyngeal carcinoma. MRI revealed the extent of the tumor more clearly than CT (computed tomography) when the tumor was situated in the parapharyngeal space. But when the tumor extended superficially in the nasopharyngeal mucosa, its margin could not be identified clearly by either MRI or CT because of hypervascularity and long T1 and T2 of the nasopharyngeal mucosa. Seven of the nine patients had unilateral otitis media with effusion. Their eustachian tube ventilation function was evaluated by an inflation-deflation technique. Failure of active equalization of negative pressure applied to the middle ear was found to be a characteristic disorder of their eustachian tube ventilation function. This dysfunction seemed to be correlated with the lateral dislocation of the eustachian tube cartilage caused by the tumor. (author)

Children's (Pediatric) Magnetic Resonance Imaging

Science.gov (United States)

... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

Magnetic Resonance Sensors

Directory of Open Access Journals (Sweden)

Robert H. Morris

2014-11-01

Full Text Available Magnetic Resonance finds countless applications, from spectroscopy to imaging, routinely in almost all research and medical institutions across the globe. It is also becoming more frequently used for specific applications in which the whole instrument and system is designed for a dedicated application. With beginnings in borehole logging for the petro-chemical industry Magnetic Resonance sensors have been applied to fields as varied as online process monitoring for food manufacture and medical point of care diagnostics. This great diversity is seeing exciting developments in magnetic resonance sensing technology published in application specific journals where they are often not seen by the wider sensor community. It is clear that there is enormous interest in magnetic resonance sensors which represents a significant growth area. The aim of this special edition of Sensors was to address the wide distribution of relevant articles by providing a forum to disseminate cutting edge research in this field in a single open source publication.[...

Magnetic resonance imaging of the brain in congenital rubella virus and cytomegalovirus infections

International Nuclear Information System (INIS)

Sugita, K.; Ando, M.; Makino, M.; Takanashi, J.; Fujimoto, N.; Niimi, H.

1991-01-01

Two children with congenital rubella virus and six with cytomegalovirus (CMV) infections, were examined by magnetic resonance (MR) and CT. Cranial MR imaging (MRI) with T2-weighted spin-echo (SE) and inversion recovery (IR) sequences demonstrated the following: Periventricular hyperintensity (4), subcortical hyperintensity (5), delayed myelination (4), oligo/pachygyria (2), cerebellar hypoplasia (2). This study showed that the more-disabled children had more marked abnormal MRI findings. MRI was more effective in the detection of parenchymal lesion than was CT, although intraventricular calcification was better visualized with CT. (orig.)

Magnetic Resonance Imaging (MRI) -- Head

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging ( ... the limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a ...

Magnetic resonance angiography (MRA)

International Nuclear Information System (INIS)

Arlart, I.P.; Guhl, L.

1992-01-01

An account is given in this paper of the physical and technical principles underlying the 'time-of-flight' technique for imaging of vessels by magnetic resonance tomography. Major indications for the new procedure of magnetic resonance angiography at present are intracerebral and extracerebral vessels, with digital subtraction angiography quite often being required to cope with minor alterations (small aneurysms, small occlusions). Magnetic resonance angiography and digital subtraction angiography are compared to each other for advantages and disadvantages. Basically, replacement of radiological angiography by magnetic resonance angiography appears to be possible only within limits, since X-ray diagnostics primarily provides morphological information about vessels, whereas flow dynamics is visualized by the 'time-of-flight' technique. (orig.) [de

Parameters and definitions in applied technique quality test for nuclear magnetic resonance imaging system (NMRI)

International Nuclear Information System (INIS)

Lin Zhikai; Zhao Lancai

1999-08-01

During the past two decades, medical diagnostic imaging technique has achieved dramatic development such as CT, MRI, PET, DSA and so on. The most striking examples of them are the application of X ray computerized tomography (CT) and magnetic resonance imaging in the field of medical diagnosis. It can be predicted that magnetic resonance imaging (MRI) will definitely have more widespread prospects of applications and play more and more important role in clinical diagnosis looking forward to the development of image diagnostic technique for 21 st century. The authors also present the measuring methods for some parameters. The parameters described can be used for reference by clinical diagnosticians, operators on MRI and medical physicists who engages in image quality assurance (QA) and control (QC) in performing MRI acceptance test and routine test

Nuclear magnetic resonance imaging with cardiac synchronization in chronic thrombosis of main pulmonary arteries. A case review with CT scan imaging correlation

International Nuclear Information System (INIS)

Coulomb, M.; Wolf, J.E.; Rose-Pittet, L.; Le Bas, J.F.; Dalsoglio, S.; Paramelle, B.

1986-01-01

Results of nuclear magnetic resonance exploration in a patient with chronic thrombosis of main pulmonary arteries are used to outline an elementary semiology in agreement with current documented data. Signs observed relate to the thrombosis and showing of flow due to associated pulmonary artery hypertension. Cardiac synchronization is essential: obtaining 2 echos by the spin-echo technique allows differentiation of circulatory slowing phenomena, which provoke increased strength of 2nd echo, from the thrombus itself. Correlations established with V/Q scintigraphy, angiography and CT scan findings in this case provided preliminary evaluation of use of this imaging technique in this affection [fr

Magnetic resonance imaging in inflammatory lesions of the middle ear

International Nuclear Information System (INIS)

Tono, Tetsuya; Saku, Kazuaki; Miyanaga, Satoshi; Kano, Kiyo; Morimitsu, Tamotsu; Suzuki, Yukiko.

1988-01-01

Eighteen patients with chronic otitis media, middle ear cholesteatoma, and postoperative inflammatory diseases of the middle ear underwent high resolution computerized tomography (CT) and magnetic resonance imaging (MRI) before surgical exploration of the middle ear. Results showed that CT provides higher detail resolution in middle ear structures, but provides limited density resolution in displaying inflammatory soft tissue lesions. By contrast, MRI differentiates among soft tissue lesions such as fluid-filled spaces, granulation tissues, and cholesteatomatous debris. Cholesterin granulomas show a particularly characteristic signal pattern with a very high intensity area in both T1 and T2 weighted images. It is concluded that MRI is useful in differentiating soft tissue density masses when used in conjunction with CT in middle ear inflammatory diseases. (author)

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

Magnetic nanoparticles in magnetic resonance imaging and diagnostics.

Science.gov (United States)

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.

Clinical application of magnetic resonance in acute traumatic brain injury

Energy Technology Data Exchange (ETDEWEB)

Morais, Dionei F.; Gaia, Felipe F.P. [Hospital de Base de Sao Jose do Rio Preto, SP (Brazil). Servico de Neurocirurgia]. E-mail: centro@cerebroecoluna.com.br; Spotti, Antonio R.; Tognola, Waldir A. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Ciencias Neurologicas; Andrade, Almir F. [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Dept. de Neurocirurgia da Emergencia

2008-07-01

Purpose: To evaluate the clinical applications of magnetic resonance imaging (MRI) in patients with acute traumatic brain injury (TBI): to identify the type, quantity, severity; and improvement clinical-radiological correlation. Method: Assessment of 55 patients who were imaged using CT and MRI, 34 (61.8%) males and 21 (38.2%) females, with acute (0 to 5 days) and closed TBI. Results: Statistical significant differences (McNemar test): occurred fractures were detected by CT in 29.1% and by MRI in 3.6% of the patients; subdural hematoma by CT in 10.9% and MRI in 36.4 %; diffuse axonal injury (DAI) by CT in 1.8% and MRI in 50.9%; cortical contusions by CT in 9.1% and MRI in 41.8%; subarachnoid hemorrhage by CT in 18.2% and MRI in 41.8%. Conclusion: MRI was superior to the CT in the identification of DAI, subarachnoid hemorrhage, cortical contusions, and acute subdural hematoma; however it was inferior in diagnosing fractures. The detection of DAI was associated with the severity of acute TBI. (author)

Clinical application of magnetic resonance in acute traumatic brain injury

International Nuclear Information System (INIS)

Morais, Dionei F.; Gaia, Felipe F.P.; Spotti, Antonio R.; Tognola, Waldir A.; Andrade, Almir F.

2008-01-01

Purpose: To evaluate the clinical applications of magnetic resonance imaging (MRI) in patients with acute traumatic brain injury (TBI): to identify the type, quantity, severity; and improvement clinical-radiological correlation. Method: Assessment of 55 patients who were imaged using CT and MRI, 34 (61.8%) males and 21 (38.2%) females, with acute (0 to 5 days) and closed TBI. Results: Statistical significant differences (McNemar test): occurred fractures were detected by CT in 29.1% and by MRI in 3.6% of the patients; subdural hematoma by CT in 10.9% and MRI in 36.4 %; diffuse axonal injury (DAI) by CT in 1.8% and MRI in 50.9%; cortical contusions by CT in 9.1% and MRI in 41.8%; subarachnoid hemorrhage by CT in 18.2% and MRI in 41.8%. Conclusion: MRI was superior to the CT in the identification of DAI, subarachnoid hemorrhage, cortical contusions, and acute subdural hematoma; however it was inferior in diagnosing fractures. The detection of DAI was associated with the severity of acute TBI. (author)

Magnetic resonance fingerprinting.

Science.gov (United States)

Ma, Dan; Gulani, Vikas; Seiberlich, Nicole; Liu, Kecheng; Sunshine, Jeffrey L; Duerk, Jeffrey L; Griswold, Mark A

2013-03-14

Magnetic resonance is an exceptionally powerful and versatile measurement technique. The basic structure of a magnetic resonance experiment has remained largely unchanged for almost 50 years, being mainly restricted to the qualitative probing of only a limited set of the properties that can in principle be accessed by this technique. Here we introduce an approach to data acquisition, post-processing and visualization--which we term 'magnetic resonance fingerprinting' (MRF)--that permits the simultaneous non-invasive quantification of multiple important properties of a material or tissue. MRF thus provides an alternative way to quantitatively detect and analyse complex changes that can represent physical alterations of a substance or early indicators of disease. MRF can also be used to identify the presence of a specific target material or tissue, which will increase the sensitivity, specificity and speed of a magnetic resonance study, and potentially lead to new diagnostic testing methodologies. When paired with an appropriate pattern-recognition algorithm, MRF inherently suppresses measurement errors and can thus improve measurement accuracy.

Advances in magnetic resonance 6

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 6 focuses on the theoretical and practical aspects of applying magnetic resonance methods to various problems in physical chemistry, emphasizing the different aspects of the exegesis of these problems. This book discusses the gas phase magnetic resonance of electronically excited molecules; techniques for observing excited electronic states; NMR studies in liquids at high pressure; and effect of pressure on self-diffusion in liquids. The nuclear magnetic resonance investigations of organic free radicals; measurement of proton coupling constants by NMR; an

Magnetic resonance imaging in the acute stage of cerebrovascular disease

International Nuclear Information System (INIS)

Tanaka, Tokutaro; Sakai, Tsuneo; Fujishima, Ichiro; Yamamoto, Takamichi; Uemura, Kenichi; Teramura, Atsushi.

1988-01-01

Thirty patients with acute cerebrovascular disease were evaluated by both computed tomography (CT) and magnetic resonance (MR) imaging. The 17 patients with cerebral infarction (CI) were evaluated within 24 hours and the 13 with intracerebral hemorrhage (ICH) within 6 hours of the onset of symptoms. All ICHs were detected in T2-weighted images and appeared as perifocal, ring-like areas of high signal intensity. T2-weighted images also demonstrated a ruptured aneurysm and an arteriovenous malformation. In T1-weighted images, all ICHs displayed high signal intensity, which paralleled the CT images and is characteristic of MR imaging with an ultra-low magnetic filed. These findings were obtained as early as 90 minutes from the onset of symptoms. In cases of CI, T2-weighted images obtained 3 - 7 hours after onset demonstrated the pathology more clearly than did CT. This study proved MR imaging useful in the evaluation of both ICH and CI in the acute stage. In addition, it was possible to differentiate ICH from CI in the acute stage by T2-weighted images alone. (author)

Magnetic resonance imaging in 38 cases of acoustic tumors

Energy Technology Data Exchange (ETDEWEB)

Uchino, Masafumi; Ohtsuka, Takashi; Seiki, Yoshikatsu; Matsumoto, Mikiro; Shibata, Iekado; Terao, Hideo [Toho Univ., Tokyo (Japan). School of Medicine; Kohno, Takeshi; Sanpei, Kenji; Mano, Isamu

1989-08-01

The value of magnetic resonance imaging (MRI) in the diagnosis of acoustic tumors was retrospectively assessed in 38 cases. A 0.15 Tesla permanent magnet and a 1.5 Tesla superconducting magnet were employed in 24 and 14 cases, respectively. Gadolinium diethlene triamine pentaacetic acid (Gd-DTPA), a paramagnetic contrast agent, was used in 10 cases. Acoustic tumors were identified in all cases. Small, medium, and large tumors were depicted with equal clarity by MRI and computed tomography (CT). However, tumor contour and extension, accompanying cysts, and brainstem displacement were more clarly visualized on MRI. The use of Gd-DTPA improved the quality of the MR images by markedly enhancing the acoustic tumors in all cases. In particular, detection of small acoustic tumors and intra- or paratumoral cysts was facilitated by the use of Gd-DTPA. The possibility of a correlation between acoustic tumor histology and MRI features was studied by calculation of the contrast to noise (C/N) ratio in 10 cases of acoustic tumor and 7 cases of meningioma. No definite correlation was demonstrated, but there appeared to be some difference in the C/N ratio between acoustic tumors and meningiomas. In three volunteers, MRI demonstrated intracanalicular nerves, separately. Because of its higher resolution, MRI can be expected to replace CT and air CT in the diagnosis of acoustic tumors. (author).

A high-resolution EPR-CT microscope using cavity-resonators equipped with small field gradient coils

International Nuclear Information System (INIS)

Miki, T.; Murata, T.; Kumai, H.; Yamashiro, A.

1996-01-01

Cylindrical cavity resonators equipped with field gradient coils were developed for two-dimensional EPR-CT microscope systems. The field gradient coils lie in four (or six) thin metal tubes placed along the direction of the microwave magnetic field in the cavity to minimize impact on the resonator's quality factor. Two pairs of the tubes carry a 100 kHz current for magnetic field modulation. This cavity has high spin-detection sensitivity and can provide EPR images with submillimeter resolution. In order to reconstruct better images from fewer projections, we used an algebraic reconstruction technique (ART) for the two-dimensional image reconstruction. The ART method may be suitable for not only spectral-spatial two-dimensional EPR imaging, but also spatio-temporal EPR imaging in dynamic spin systems. (author)

Magnetic resonance imaging of the normal and abnormal pulmonary hila

International Nuclear Information System (INIS)

Webb, W.R.; Gamsu, G.; Stark, D.D.; Moore, E.H.

1984-01-01

Magnetic resonance (MR) images of the hila were reviewed in 25 normal subjects and 12 patients with unilateral or bilateral hilar masses. On spin echo MR images in normal patients, collections of soft tissue large enough to be confused with an abnormally enlarged lymph node were seen in three locations. In patients with a hilar mass, the mass was differentiated from hilar vasculature more easily using MR than contrast-enhanced CT. However, because the spatial resolution of MR is inferior to that of CT, bronchi were difficult to evaulate using MR. Electrocardiographic-gated images showed better resolution of hilar structures but may not be necessary for large masses

Proton magnetic resonance spectroscopy and perfusion magnetic resonance imaging in the evaluation of musculoskeletal tumors

International Nuclear Information System (INIS)

Costa, Flavia Martins; Setti, Marcela; Vianna, Evandro Miguelote; Domingues, Romulo Cortes; Meohas, Walter; Rezende, Jose Francisco; Gasparetto, Emerson Leandro

2009-01-01

Objective: To assess the role of proton magnetic resonance spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in the differentiation between malignant and benign musculoskeletal tumors. Materials And Methods: Fifty-five patients with musculoskeletal tumors (27 malignant and 28 benign) were studied. The examinations were performed in a 1.5 T magnetic resonance scanner with standard protocol, and single voxel proton magnetic resonance spectroscopy with 135 msec echo time. The dynamic contrast study was performed using T1-weighted gradient-echo sequence after intravenous gadolinium injection. Time signal intensity curves and slope values were calculated. The statistical analysis was performed with the Levene's test, followed by a Student's t-test, besides the Pearson's chi-squared and Fischer's exact tests. Results: Proton magnetic resonance spectroscopy sensitivity, specificity and accuracy were, respectively, 87.5%, 92.3% and 90.9% (p < 0.0001). Statistically significant difference was observed in the slope (%/min) between benign (mean, 27.5%/min) and malignant (mean, 110.9%/min) lesions (p < 0.0001). Conclusion: The time-intensity curve and slope values using dynamic-enhanced perfusion magnetic resonance imaging in association with the presence of choline peak demonstrated by single voxel magnetic resonance spectroscopy study are useful in the differentiation between malignant and benign musculoskeletal tumors. (author)

Dosimetric and geometric evaluation of an open low-field magnetic resonance simulator for radiotherapy treatment planning of brain tumours

DEFF Research Database (Denmark)

Kristensen, B.H.; Laursen, F.J.; Logager, V.

2008-01-01

Background and purpose: Magnetic resonance (MR) imaging is superior to computed tomography (CT) in radiotherapy of brain tumours. In this study an open low-field MR-simulator is evaluated in order to eliminate the cost of and time spent on additional CT scanning. Materials and methods: Eleven...

Migrational disorders: a review of 13 cases. Computed tomography and Magnetic resonance imaging

International Nuclear Information System (INIS)

Machado Junior, M.A.; Barbosa, V.A.; Puglio, N.; Bastos, C.A.

1994-01-01

The authors reviewed 13 cases of migrational disorders using Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). They found a large advantage of MRI in relation to CT, mainly, to study Schizencephaly, because MRI is more efficient way to demonstrate that the margins of the clefts are lined by cortical and make reliable differentiation with Porencephalic cysts. The relationship of the pathological anatomy to theories of pathogenesis is emphasized. No abnormal findings was detected in the process of Myelinization. (author)

Magnetic resonance imaging of penile metastases: a report on five cases

Energy Technology Data Exchange (ETDEWEB)

Lau, T.N. [Singapore General Hospital, (Singapore). Department of Diagnostic Radiology; Wakeley, C.J.; Goddard, P. [Bristol Royal Infirmary, Bristol, (United Kingdom). Department of Clinical Radiology

1999-08-01

Five cases of penile metastases are presented. Axial and sagittal T1-weighted and T2-weighted scans were performed in all patients. In some, coronal images were also obtained. The penile metastases were most often seen as discrete masses in the corpora cavernosa or corpus spongiosum. An atypical pattern of diffuse infiltration is also illustrated. Limitations of cavernosography, ultrasound (US) and computed tomography (CT) are discussed. The magnetic resonance (MR) features of penile metastases and possible role MR may have in the management of these patients are described. Metastatic deposits in the penis are uncommon. First described by Eberth in 1870 in a patient with a primary rectal carcinoma, there have since been over 300 cases reported in the literature. The imaging of penile metastases is, however, less clearly defined. Until now, cavernosography, ultrasound (US) and computed tomography (CT) have been used. These techniques have limitations. Only recently has magnetic resonance imaging (MRI) been employed. We describe five cases of penile metastases evaluated with MRI and discuss the role and features of penile metastases on MRI. Copyright (1999) Blackwell Science Pty Ltd 12 refs., 4 figs.

Magnetic resonance imaging of the genitourinary tract

International Nuclear Information System (INIS)

Strake, L. te; Persijn van Meerten, E.L. van; Trimbos, J.B.M.Z.; Paul, L.C.; Langeveld, J.W.; Bloem, J.L.; Bluemm, R.G.; Doornbos, J.

1986-01-01

This is an overview of the current applications of magnetic resonance imaging (MRI) in the genitourinary tract based on the experience with the 0.5-Tesla MR scanner (Gyroscan, Philips) at the Leiden University Hospital and on reports in the literature. MRI appears to share some of the limitations of CT. MRI cannot reliably differentiate between a malignant and a benign tumor. In the staging of ovarian malignancies by means of MRI, bowel preparation would be desirable. On the other hand, the soft-tissue contrast resolution of MRI is superior to that of CT and images can be obtained in any plane. Thus MRI promises to be an accurate method for staging malignancies. The results in the examination of transplant kidneys are encouraging. It is expected that there will be a place for MRI as a complementary technique to ultrasonography in the diagnosis of scrotal disease. (Auth.)

Magnetic resonance imaging and computed tomography as tools for the investigation of sperm whale (Physeter macrocephalus) teeth and eye

DEFF Research Database (Denmark)

Alstrup, Aage Kristian Olsen; Munk, Ole Lajord; Jensen, Trine Hammer

2017-01-01

Background: Scanning techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) are useful tools in veterinary and human medicine. Here we demonstrate the usefulness of these techniques in the study of the anatomy of wild marine mammals as part of a necropsy. MRI and CT scan...

Hepatic involvement of Langerhans cell histiocytosis in children - imaging findings of computed tomography, magnetic resonance imaging and magnetic resonance cholangiopancreatography

International Nuclear Information System (INIS)

Shi, Yingyan; Qiao, Zhongwei; Gong, Ying; Yang, Haowei; Li, Guoping; Pa, Mier; Xia, Chunmei

2014-01-01

Langerhans cell histiocytosis is a rare disease that occurs mainly in children, and hepatic involvement is generally a poor prognostic factor. To describe CT and MRI findings of hepatic involvement of Langerhans cell histiocytosis in children, especially the abnormal bile duct manifestation on magnetic resonance cholangiopancreatography (MRCP). Thirteen children (seven boys, six girls; mean age 28.9 months) were diagnosed with disseminated Langerhans cell histiocytosis. They underwent CT (n = 5) or MRI (n = 4), or CT and MRI examinations (n = 4) to evaluate the liver involvement. Periportal abnormalities presented as band-like or nodular lesions on CT and MRI in all 13 children. The hepatic parenchymal lesions were found in the peripheral regions of the liver in seven children, including multiple nodules on MRI (n = 6), and cystic-like lesions on CT and MRI (n = 3). In 11 of the 13 children the dilatations of the bile ducts were observed on CT and MRI. Eight of the 13 children underwent MR cholangiopancreatography, which demonstrated stenoses or segmental stenoses with slight dilatation of the central bile ducts, including the common hepatic duct and its first-order branches. The peripheral bile ducts in these children showed segmental dilatations and stenoses. Stenosis of the central bile ducts revealed by MR cholangiopancreatography was the most significant finding of liver involvement in Langerhans cell histiocytosis in children. (orig.)

Hepatic involvement of Langerhans cell histiocytosis in children - imaging findings of computed tomography, magnetic resonance imaging and magnetic resonance cholangiopancreatography

Energy Technology Data Exchange (ETDEWEB)

Shi, Yingyan; Qiao, Zhongwei; Gong, Ying; Yang, Haowei; Li, Guoping; Pa, Mier [Children' s Hospital of Fudan University, Department of Radiology, Shanghai (China); Xia, Chunmei [Shanghai Medical College of Fudan University, Physiology and Pathophysiology Department, Shanghai (China)

2014-06-15

Langerhans cell histiocytosis is a rare disease that occurs mainly in children, and hepatic involvement is generally a poor prognostic factor. To describe CT and MRI findings of hepatic involvement of Langerhans cell histiocytosis in children, especially the abnormal bile duct manifestation on magnetic resonance cholangiopancreatography (MRCP). Thirteen children (seven boys, six girls; mean age 28.9 months) were diagnosed with disseminated Langerhans cell histiocytosis. They underwent CT (n = 5) or MRI (n = 4), or CT and MRI examinations (n = 4) to evaluate the liver involvement. Periportal abnormalities presented as band-like or nodular lesions on CT and MRI in all 13 children. The hepatic parenchymal lesions were found in the peripheral regions of the liver in seven children, including multiple nodules on MRI (n = 6), and cystic-like lesions on CT and MRI (n = 3). In 11 of the 13 children the dilatations of the bile ducts were observed on CT and MRI. Eight of the 13 children underwent MR cholangiopancreatography, which demonstrated stenoses or segmental stenoses with slight dilatation of the central bile ducts, including the common hepatic duct and its first-order branches. The peripheral bile ducts in these children showed segmental dilatations and stenoses. Stenosis of the central bile ducts revealed by MR cholangiopancreatography was the most significant finding of liver involvement in Langerhans cell histiocytosis in children. (orig.)

Nodal involvement in Hodgkin disease and non-Hodgkin lymphoma assessed by magnetic resonance

International Nuclear Information System (INIS)

Tesoro Tess, J.D.; Balzarini, L.; Ceglia, E.; Petrillo, R.; Musumeci, R.

1990-01-01

Magnetic Resonance Imaging (MRI) demonstrates a good capability in distinguishing nodal involvement in hodgkin disease and nonhodgkin lymphoma both in the chest and in the retroperitoneal areas the initial presentation of the disease. However CT and lymphangiography demonstrated comparable or superior values of accuracy and sensitivity. (H.W.) 4 refs.; 2 tabs

Magnetic resonance imaging of lumbar vertebral apophyseal ring fractures

International Nuclear Information System (INIS)

Peh, W.C.G.

1998-01-01

Posterior lumbar vertebral apophyseal ring fractures are described in three adolescents presenting with severe low back pain, spinal tenderness and lower limb neurological deficit. Magnetic resonance imaging showed severe L4/5 posterior disc protrusion in all three patients. The actual fracture fragment was visualized with difficulty on MRI alone. The diagnosis of apophyseal ring fracture was made by either radiography or CT. Computed tomography delineated the size, shape and site of the fracture fragment. Surgical confirmation was obtained in all cases. Posterior lumbar vertebral apophyseal ring fractures may be difficult to visualize on MR imaging. Careful review of radiographs, supplemented by targeted CT, is necessary for the correct diagnosis and management of this entity. Copyright (1998) Blackwell Science Pty Ltd

Magnetic resonance imaging of lumbar vertebral apophyseal ring fractures

Energy Technology Data Exchange (ETDEWEB)

Peh, W.C.G. [University of Hong Kong (Hong Kong). Department of Diagnostics Radiology and Organ Imaging; Yip, D.K.H.; Leong, J.C.Y. [University of Hong Kong (Hong Kong). Department of Orthopaedic Surgery; Griffith, J.F. [Chinese University of Hong Kong (Hong Kong)

1998-02-01

Posterior lumbar vertebral apophyseal ring fractures are described in three adolescents presenting with severe low back pain, spinal tenderness and lower limb neurological deficit. Magnetic resonance imaging showed severe L4/5 posterior disc protrusion in all three patients. The actual fracture fragment was visualized with difficulty on MRI alone. The diagnosis of apophyseal ring fracture was made by either radiography or CT. Computed tomography delineated the size, shape and site of the fracture fragment. Surgical confirmation was obtained in all cases. Posterior lumbar vertebral apophyseal ring fractures may be difficult to visualize on MR imaging. Careful review of radiographs, supplemented by targeted CT, is necessary for the correct diagnosis and management of this entity. Copyright (1998) Blackwell Science Pty Ltd 12 refs., 3 figs.

Magnetic resonance imaging in the evaluation of the brainstem

International Nuclear Information System (INIS)

Han, J.S.; Bonstelle, C.T.; Kaufman, B.; Benson, J.E.; Alfidi, R.J.; Clampitt, M.; Van Dyke, C.; Huss, R.G.

1984-01-01

Magnetic resonance (MR) images of the brainstem region from 100 normal or asymptomatic individuals were reviewed in addition to those of 17 patients with intra-axial brainstem lesions and 15 patients with extra-axial masses around the brainstem. MR was able to demonstrate consistently the normal anatomy of the brainstem and adjacent cisterns, though the distinction between gray and white matter was seldom possible with the present technology. Masses in and around the brainstem were all accurately identified on MR and its sensitivity was superior to that of x-ray computed tomography (CT). These study results show that despite its technical limitations, MR is presently the examination of choice for the evaluation of brainstem abnormalities and eventually it will undoubtedly replace metrizamide CT cisternography

Magnetic resonance for wireless power transfer

OpenAIRE

Hui, SYR

2016-01-01

Magnetic resonance has been a cornerstone of nonradiative wireless power transfer (WPT) since the late 19th century. However, some researchers have the misconception that magnetic resonance for WPT was developed recently. This article traces some early work of Tesla and other researchers related to the use of magnetic resonance in WPT. Included are some examples of magnetic resonance-based WPT projects conducted by researchers in the biomedical and power electronics communities over the last ...

Cardiac magnetic resonance imaging

African Journals Online (AJOL)

2011-03-06

Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

Magnetic resonance imaging of lumbar spine disc diseases. Frequency of false negatives

International Nuclear Information System (INIS)

Berthelot, J.M.; Maugars, Y.; Delecrin, Y.; Caillon, F.; Prost, A.

1995-01-01

Magnetic resonance imaging (MRI) has had an impressive impact on evaluation of degenerative diseases of the spine. Nevertheless, false negatives can occur on images involving lumbar discs. Degenerative disc diseases documented on discography and/or pathology examination of the discs can go unrecognized. Likewise sensitivity for the detection of protruding disc hernias is not totally satisfactory (20% false negatives). Finally, a magnetic resonance image visualizing displacement of the disc is not specific (10 to 15% false positives); images showing protrusion or hernia can be seen in 30% of asymptomatic patients. Although MRI gives slightly more information than other imaging techniques, false images do exist. Moreover, the usefulness of MRI to demonstrate disc disease in case of a negative CT-scan remains to be demonstrated. (authors). 26 refs

Advances in magnetic resonance 12

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 12, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains six chapters and begins with a discussion of diffusion and self-diffusion measurements by nuclear magnetic resonance. This is followed by separate chapters on spin-lattice relaxation time in hydrogen isotope mixtures; the principles of optical detection of nuclear spin alignment and nuclear quadropole resonance; and the spin-1 behavior, including the relaxation of the quasi-invariants of the motion of a system of pairs of dipolar coupled spin-1/2 nu

Magnetic Resonance Force Microscopy System

Data.gov (United States)

Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

Correlation of computed tomographic and magnetic resonance imaging findings in cerebral infartion

International Nuclear Information System (INIS)

Komatsubara, Chizuko; Chuda, Moriyoshi; Taka, Toshihiko

1989-01-01

We evaluated neurological findings in 75 patients of cerebral infarction, and correlated computed tomographic (CT) and magnetic resonance imaging (MRI) findings. MRI was found to have the advantage when the lesion were multiple, or in the posterior fossa. MRI demonstrates the anatomical details, and lacks the bony artifact, so it is an excellent method for identification of cerebral infarction. (author)

Magnetic resonance imaging

International Nuclear Information System (INIS)

Robertson, Angus

1990-01-01

An assessment is made of the clinical benefits of expensive diagnostic technology, such as the magnetic resonance imaging. It is concluded that to most radiologists, magnetic resonance imaging has a definite place in the diagnostic scenario, especially for demonstrating central nervous system lesions in multiple sclerosis. While it is recognized that medical and financial resources are limited, it is emphasised that the cost to society must be balanced against the patient benefit. 17 refs

Magnetic resonance imaging in the staging of renal cell carcinoma

Energy Technology Data Exchange (ETDEWEB)

Kishi, Hiroichi; Umeda, Takashi; Niijima, Tadao; Yashiro, Naobumi; Kawabe, Kazuki

1987-07-01

Eighteen patients with renal neoplasm underwent magnetic resonance imaging (MRI) using a 1.5 Tesla superconducting magnetic system and spin echo images were obtained by quick scan technique under holding breath. MR images were interpreted independently of the computerized tomography (CT) findings. The preoperative stagings of the 18 renal carcinomas, as judged by MRI, were compared with those obtained at laparotomy. The anatomic staging was correctly performed by MRI in 13 patients (72 %). In the patients who had intrarenal small tumor with normal renal contour, MRI demonstrated a solid mass clearly distinguishable from surrounding renal parenchyma using the paramagnetic contrast agent (gadolinium-DTPA). When compared with results of evaluation by CT in staging, MRI appeared to have several advantages in determination of whole mass; the detection of tumor thrombus into renal vein and inferior vena cava; and the evaluation of direct tumor invasion of adjacent organs. MRI should play an important role in the staging of renal cell carcinoma.

Magnetic resonance imaging in the staging of renal cell carcinoma

International Nuclear Information System (INIS)

Kishi, Hiroichi; Umeda, Takashi; Niijima, Tadao; Yashiro, Naobumi; Kawabe, Kazuki

1987-01-01

Eighteen patients with renal neoplasm underwent magnetic resonance imaging (MRI) using a 1.5 Tesla superconducting magnetic system and spin echo images were obtained by quick scan technique under holding breath. MR images were interpreted independently of the computerized tomography (CT) findings. The preoperative stagings of the 18 renal carcinomas, as judged by MRI, were compared with those obtained at laparotomy. The anatomic staging was correctly performed by MRI in 13 patients (72 %). In the patients who had intrarenal small tumor with normal renal contour, MRI demonstrated a solid mass clearly distinguishable from surrounding renal parenchyma using the paramagnetic contrast agent (gadolinium-DTPA). When compared with results of evaluation by CT in staging, MRI appeared to have several advantages in determination of whole mass; the detection of tumor thrombus into renal vein and inferior vena cava; and the evaluation of direct tumor invasion of adjacent organs. MRI should play an important role in the staging of renal cell carcinoma. (author)

Advances in magnetic resonance 11

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 11, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters and begins with a discussion of the principles and applications of dynamic nuclear polarization, with emphasis on molecular motions and collisions, intermolecular couplings, and chemical interactions. Subsequent chapters focus on the assessment of a proposed broadband decoupling method and studies of time-domain (or Fourier transform) multiple-quantum nuclear magnetic resonance.

Imaging in hematology. Part 2: Computed tomography, magnetic resonance imaging and nuclear imaging

International Nuclear Information System (INIS)

Zhechev, Y.

2003-01-01

A dramatic increase of the role of imaging in diagnosis of blood diseases occurred with the development of computed tomography (CT) and magnetic resonance imaging (MRI). At present CT of the chest, abdomen, and pelvis is routinely employed in diagnostic and staging evaluation. The bone marrow may be imaged by one of several methods, including scintigraphy, CT and MRI. Nuclear imaging at diagnosis can clarify findings of uncertain significance on conventional staging and may be very useful in the setting of large masses to follow responses to therapy nad to evaluate the residual tumor in a large mass that has responded to treatment. Recent developments such as helical CT, single proton emission computed tomography (SPECT) and positron-emission tomography (PET) have continued to advance diagnosis and therapy

Magnetic resonance imaging: effects of magnetic field strength

International Nuclear Information System (INIS)

Crooks, L.E.; Arakawa, M.; Hoenninger, J.; McCarten, B.; Watts, J.; Kaufman, L.

1984-01-01

Magnetic resonance images of the head, abdomen, and pelvis of normal adult men were obtained using varying magnetic field strength, and measurements of T1 and T2 relaxations and of signal-to-noise (SN) ratios were determined. For any one spin echo sequence, gray/white matter contrast decreases and muscle/fat contrast increases with field. SN levels rise rapidly up to 3.0 kgauss and then change more slowly, actually dropping for muscle. The optimum field for magnetic resonance imaging depends on tissue type, body part, and imaging sequence, so that it does not have a unique value. Magnetic resonance systems that operate in the 3.0-5.0 kgauss range achieve most or all of the gains that can be achieved by higher magnetic fields

Introduction lecture to magnetic resonance

International Nuclear Information System (INIS)

Conard, J.

1980-01-01

This lecture deals with all that is common either to electron paramagnetic resonance (E.P.R.) or to nuclear magnetic resonance (N.M.R.). It will present, in an as elementary form as possible, the main concepts used in magnetic resonance emphasizing some aspects, specific for interface science. (orig./BHO)

Comparative study of ultrasound imaging, computed tomography and magnetic resonance imaging in gynecology

International Nuclear Information System (INIS)

Ishii, Kenji; Kobayashi, Hisaaki; Hoshihara, Takayuki; Kobayashi, Mitsunao; Suda, Yoshio; Takenaka, Eiichi; Sasa, Hidenori.

1989-01-01

We studied 18 patients who were operated at the National Defense Medical College Hospital and confirmed by pathological diagnosis. We compared ultrasound imaging, computed tomography (CT) and magnetic resonance imaging (MRI) of the patients. MRI was useful to diagnose enlargement of the uterine cavity and a small amount of ascites and to understand orientation of the pelvic organs. Ultrasound imaging is the most useful examination to diagnose gynecological diseases. But when it is difficult to diagnose by ultrasound imaging alone, we should employ either CT or MRI, or preferably both. (author)

Computed tomography synthesis from magnetic resonance images in the pelvis using multiple random forests and auto-context features

DEFF Research Database (Denmark)

Andreasen, Daniel; Morgenthaler Edmund, Jens; Zografos, Vasileios

2016-01-01

In radiotherapy treatment planning that is only based on magnetic resonance imaging (MRI), the electron density information usually obtained from computed tomography (CT) must be derived from the MRI by synthesizing a so-called pseudo CT (pCT). This is a non-trivial task since MRI intensities...... as measured by water-equivalent path lengths. We compare the performance of our method against two baseline pCT strategies, which either set all MRI voxels in the subject equal to the CT value of water, or in addition transfer the bone volume from the real CT. We show an improved performance compared to both...

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... can help plan the safest and most effective surgery. CT of the sinuses is now widely available and is performed in a relatively short time, especially when compared to magnetic resonance imaging (MRI). CT scanning is painless, noninvasive and ...

Implementation of a Novel Algorithm For Generating Synthetic CT Images From Magnetic Resonance Imaging Data Sets for Prostate Cancer Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Kim, Joshua, E-mail: jkim8@hfhs.org; Glide-Hurst, Carri; Doemer, Anthony; Wen, Ning; Movsas, Benjamin; Chetty, Indrin J.

2015-01-01

Purpose: To describe and evaluate a method for generating synthetic computed tomography (synCT) images from magnetic resonance simulation (MR-SIM) data for accurate digitally reconstructed radiograph (DRR) generation and dose calculations in prostate cancer radiation therapy. Methods and Materials: A retrospective evaluation was performed in 9 prostate cancer patients who had undergone MR-SIM in addition to CT simulation (CT-SIM). MR-SIM data were used to generate synCT images by using a novel, voxel-based weighted summation approach. A subset of patients was used for weight optimization, and the number of patients to use during optimization was determined. Hounsfield unit (HU) differences between CT-SIM and synCT images were analyzed via mean absolute error (MAE). Original, CT-based treatment plans were mapped onto synCTs. DRRs were generated, and agreement between CT and synCT-generated DRRs was evaluated via Dice similarity coefficient (DSC). Dose was recalculated, and dose-volume metrics and gamma analysis were used to evaluate resulting treatment plans. Results: Full field-of-view synCT MAE across all patients was 74.3 ± 10.9 HU with differences from CTs of 2.0 ± 8.1 HU and 11.9 ± 46.7 HU for soft tissue structures (prostate, bladder, and rectum) and femoral bones, respectively. Calculated DSCs for anterior-posterior and lateral DRRs were 0.90 ± 0.04 and 0.92 ± 0.05, respectively. Differences in D99%, mean dose, and maximum dose to the clinical target volume from CT-SIM dose calculations were 0.75% ± 0.35%, 0.63% ± 0.34%, and 0.54% ± 0.33%, respectively, for synCT-generated plans. Gamma analysis (2%/2 mm dose difference/distance to agreement) revealed pass rates of 99.9% ± 0.1% (range, 99.7%-100%). Conclusion: Generated synCTs enabled accurate DRR generation and dose computation for prostate MR-only simulation. Dose recalculated on synCTs agreed well with original planning distributions. Further validation using a larger patient

Advances in magnetic resonance 9

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 9 describes the magnetic resonance in split constants and dipolar relaxation. This book discusses the temperature-dependent splitting constants in the ESR spectra of organic free radicals; temperature-dependent splittings in ion pairs; and magnetic resonance induced by electrons. The electron impact excitation of atoms and molecules; intramolecular dipolar relaxation in multi-spin systems; and dipolar cross-correlation problem are also elaborated. This text likewise covers the NMR studies of molecules oriented in thermotropic liquid crystals and diffusion

Assessment of ablative margin after radiofrequency ablation for hepatocellular carcinoma; comparison between magnetic resonance imaging with ferucarbotran and enhanced CT with iodized oil deposition

International Nuclear Information System (INIS)

Koda, Masahiko; Tokunaga, Shiho; Fujise, Yuki; Kato, Jun; Matono, Tomomitsu; Sugihara, Takaaki; Nagahara, Takakazu; Ueki, Masaru; Murawaki, Yoshikazu; Kakite, Suguru; Yamashita, Eijiro

2012-01-01

Background and purpose: Our aim was to investigate whether magnetic resonance imaging (MRI) with ferucarbotran administered prior to radiofrequency ablation could accurately assess ablative margin when compared with enhanced computed tomography (CT) with iodized oil marking. Materials and methods: We enrolled 27 patients with 32 hepatocellular carcinomas in which iodized oil deposits were visible throughout the nodule after transcatheter arterial chemoembolization. For these nodules, radiofrequency ablation was performed after ferucarbotran administration. We then performed T2-weighted MRI after 1 week and enhanced CT after 1 month. T2-weighted MRI demonstrated the ablative margin as a low-intensity rim. We classified the margin into three grades; margin (+): high-intensity area with a continuous low-intensity rim; margin zero: high-intensity area with a discontinuous low-intensity rim; and margin (−): high-intensity area extending beyond the low-intensity rim. Results: In 28 (86%) of 32 nodules, there was agreement between MRI and CT. The overall agreement between for the two modalities in the assessment of ablative margin was good (κ = 0.759, 95% confidence interval: 0.480–1.000, p < 0.001). In four nodules, ablative margins on MRI were underestimated by one grade compared with CT. Conclusion: MRI using ferucarbotran is less invasive and allows earlier assessment than CT. The MRI technique performed similarly to enhanced CT with iodized oil marking in evaluating the ablative margin after radiofrequency ablation.

Visualization of pulmonary nodules with magnetic resonance imaging (MRI)

International Nuclear Information System (INIS)

Plathow, C.; Deutsches Krebsforschungszentrum; Meinzer, H.-P.; Kauczor, H.-U.

2006-01-01

Visualization of pulmonary nodules using magnetic resonance imaging (MRI) plays a minor role compared with computed tomography (CT). Technical developments made it possible to apply MRI more and more frequently in functional imaging. Imaging of the motion of pulmonary nodules during respiration, e.g., to optimize high precision therapy techniques, is a new field of research. This paper describes developments in analysis and visualization of pulmonary nodules during respiration using MRI. Besides actual 2D techniques new 3D techniques to quantify motion of pulmonary nodules during respiration are presented. (orig.) [de

The hypofunctioning thyroid nodule: Radiography, computed tomography (CT) and magnetic resonance imaging (MRI)

International Nuclear Information System (INIS)

Dorn, R.; Wagner-Manslau, C.

1992-01-01

The hyperfunctioning thyroid nodule is a scintigraphic diagnosis by definition. Its dignity is assessed by fine needle aspiration biopsy. Radiographic methods and magnetic resonance imaging (MRI) are no primary tools in diagnosis of the hypofunctioning thyroid nodule but may reveal additional information, especially in cases of retrosternal goiter and thyroid malignomas. (orig.) [de

Magnetic Resonance Imaging (MRI) Safety

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining ...

Magnetic resonance study of maghemite-based magnetic fluid

International Nuclear Information System (INIS)

Figueiredo, L.C.; Lacava, B.M.; Skeff Neto, K.; Pelegrini, F.; Morais, P.C.

2008-01-01

This study reports on the magnetic resonance (MR) data (X-band experiment) of 10.2 nm average diameter maghemite nanoparticle in the temperature range of 100-230 K. Maghemite nanoparticles were suspended as low-pH ionic magnetic fluid containing 2.3x10 17 particles/cm 3 . The temperature dependence of both resonance linewidth and resonance field of the zero-field-cooled sample as well as the resonance field of the field-cooled sample (angular variation experiment) was analyzed using well-established methodology. Information regarding particle size, particle clusterization and surface magnetic anisotropy were obtained from the analysis of the MR data. The number of magnetic sites per particle from the MR data is in excellent agreement with the number provided by the transmission electron microscopy (TEM) data. The demagnetizing field value obtained from the MR data indicates cluster of particles containing on average 1.42 particles. The MR angular variation data suggest that magnetoelastic effect accounts for the non-linearity observed for the surface component of the magnetic anisotropy

Advances in magnetic resonance 1

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 1, discusses developments in various areas of magnetic resonance. The subject matter ranges from original theoretical contributions through syntheses of points of view toward series of phenomena to critical and painstaking tabulations of experimental data. The book contains six chapters and begins with a discussion of the theory of relaxation processes. This is followed by separate chapters on the development of magnetic resonance techniques for studying rate processes in chemistry and the application of these techniques to various problems; the geometri

Resonant and nonresonant magnetic scattering (invited)

International Nuclear Information System (INIS)

McWhan, D.B.; Hastings, J.B.; Kao, C.; Siddons, D.P.

1992-01-01

The tunability and the polarization of synchrotron radiation open up new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and they fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin-polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation

A superconducting magnet for whole-body magnetic-resonance imaging

International Nuclear Information System (INIS)

Kan, Hisao; Watanabe, Tsugio; Takechi, Moriaki; Ogino, Osamu; Yamada, Tadatoshi

1986-01-01

Magnetic-resonance imaging is a promising new clinical diagnosis system that employs magnetic resonance to generate cross-sectional images of the object under examination. A large magnet plays a critical role in this system-it must supply a high-strength magnetic field that meets rigid standards of space and time uniformity. Mitsubishi Electric has developed a superconducting magnet that not only offers excellent magnetic characteristics but also features reduced helium consumption and a horizontal service port, and permits direct mounting of a magnetic shield. (author)

Imaging of Anal Fistulas: Comparison of Computed Tomographic Fistulography and Magnetic Resonance Imaging

Energy Technology Data Exchange (ETDEWEB)

Liang, Changhu [Shandong Medical Imaging Research Institute, Shandong University, Jinan 250021 (China); Lu, Yongchao [Traditional Chinese Medicine Department, Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Zhao, Bin [Shandong Medical Imaging Research Institute, Shandong University, Jinan 250021 (China); Du, Yinglin [Shandong Provincial Center for Disease Control and Prevention, Public Health Institute, Jinan 250014 (China); Wang, Cuiyan [Shandong Medical Imaging Research Institute, Shandong University, Jinan 250021 (China); Jiang, Wanli [Department of Radiology, Taishan Medical University, Taian 271000 (China)

2014-07-01

The primary importance of magnetic resonance (MR) imaging in evaluating anal fistulas lies in its ability to demonstrate hidden areas of sepsis and secondary extensions in patients with fistula in ano. MR imaging is relatively expensive, so there are many healthcare systems worldwide where access to MR imaging remains restricted. Until recently, computed tomography (CT) has played a limited role in imaging fistula in ano, largely owing to its poor resolution of soft tissue. In this article, the different imaging features of the CT and MRI are compared to demonstrate the relative accuracy of CT fistulography for the preoperative assessment of fistula in ano. CT fistulography and MR imaging have their own advantages for preoperative evaluation of perianal fistula, and can be applied to complement one another when necessary.

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association ... MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging ( ...

Magnetic Resonance Imaging of Stroke

NARCIS (Netherlands)

Bouts, Mark. J. R. J.; Wu, O.; Dijkhuizen, R. M.

2017-01-01

Magnetic resonance imaging (MRI) provides a powerful (neuro)imaging modality for the diagnosis and outcome prediction after (acute) stroke. Since MRI allows noninvasive, longitudinal, and three-dimensional assessment of vessel occlusion (with magnetic resonance angiography (MRA)), tissue injury

Magnetic resonance elastometry using a single-sided permanent magnet

International Nuclear Information System (INIS)

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

2012-01-01

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. (paper)

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses ... identify and accurately characterize diseases than other imaging methods. This detail makes MRI an invaluable tool in ...

Tunable Magnetic Resonance in Microwave Spintronics Devices

Science.gov (United States)

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.

CT and MRI of hip arthroplasty

International Nuclear Information System (INIS)

Cahir, J.G.; Toms, A.P.; Marshall, T.J.; Wimhurst, J.; Nolan, J.

2007-01-01

Plain films are the initial imaging method of choice for evaluation of hip arthroplasty. Recent advances in technology and imaging techniques have largely overcome the problems of beam hardening in computed tomography (CT) and magnetic susceptibility artefact in magnetic resonance imaging (MRI). CT and MRI have now become useful imaging techniques in the assessment of hip arthroplasty

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful ... for an MRI exam contains a metal called gadolinium . Gadolinium can be used in patients with iodine ...

Fourier transform nuclear magnetic resonance

International Nuclear Information System (INIS)

Geick, R.

1981-01-01

This review starts with the basic principles of resonance phenomena in physical systems. Especially, the connection is shown between the properties of these systems and Fourier transforms. Next, we discuss the principles of nuclear magnetic resonance. Starting from the general properties of physical systems showing resonance phenomena and from the special properties of nuclear spin systems, the main part of this paper reviews pulse and Fourier methods in nuclear magnetic resonance. Among pulse methods, an introduction will be given to spin echoes, and, apart from the principle of Fourier transform nuclear magnetic resonance, an introduction to the technical problems of this method, e.g. resolution in the frequency domain, aliasing, phase and intensity errors, stationary state of the spin systems for repetitive measurements, proton decoupling, and application of Fourier methods to systems in a nonequilibrium state. The last section is devoted to special applications of Fourier methods and recent developments, e.g. measurement of relaxation times, solvent peak suppression, 'rapid scan'-method, methods for suppressing the effects of dipolar coupling in solids, two-dimensional Fourier transform nuclear magnetic resonance, and spin mapping or zeugmatography. (author)

A role of computed tomography or magnetic resonance imaging for cystic lung diseases in children

International Nuclear Information System (INIS)

Yanagihara, Jun; Shimotake, Takashi; Deguchi, Eiichi; Tokiwa, Kazuaki; Iwai, Naomi

1995-01-01

Fourteen children with cystic lung diseases were imaged using computed tomography (CT) and/or magnetic resonance imaging (MRI). These patients studied included 7 patients with bronchogenic cyst of lung, 4 with pulmonary sequestration, 1 with congenital cystic adenomatoid malformation, 1 with lung abscess, and 1 with cystic bronchoectasis. MRI identified all lesions seen on the chest radiographs. It was particularly valuable delineating contents of bronchogenic cyst without the need for contrast material enhancement. However, MRI was not quite as sensitive as CT that detected very small abnormalities, because MRI had more artifacts than those of CT. In conclusion, we believe that both CT and MRI are needed for differential diagnosis of lung diseases in children. (author)

A role of computed tomography or magnetic resonance imaging for cystic lung diseases in children

Energy Technology Data Exchange (ETDEWEB)

Yanagihara, Jun; Shimotake, Takashi; Deguchi, Eiichi; Tokiwa, Kazuaki; Iwai, Naomi [Kyoto Prefectural Univ. of Medicine (Japan)

1995-06-01

Fourteen children with cystic lung diseases were imaged using computed tomography (CT) and/or magnetic resonance imaging (MRI). These patients studied included 7 patients with bronchogenic cyst of lung, 4 with pulmonary sequestration, 1 with congenital cystic adenomatoid malformation, 1 with lung abscess, and 1 with cystic bronchoectasis. MRI identified all lesions seen on the chest radiographs. It was particularly valuable delineating contents of bronchogenic cyst without the need for contrast material enhancement. However, MRI was not quite as sensitive as CT that detected very small abnormalities, because MRI had more artifacts than those of CT. In conclusion, we believe that both CT and MRI are needed for differential diagnosis of lung diseases in children. (author).

Magnetic resonance in multiple sclerosis

International Nuclear Information System (INIS)

Scotti, G.; Caputo, D.; Cazzullo, C.L.

1986-01-01

Magnetic Resonance Imaging was performed in more than 200 patients with clinical suspicion or knowledge of Multiple Sclerosis. One hundred and forty-seven (60 males and 87 females) had MR evidence of multiple sclerosis lesions. The MR signal of demyelinating plaques characteristically has prolonged T1 and T2 relaxation times and the T2-weighted spin-echo sequences are generally superior to the T1-weighted images because the lesions are better visualized as areas of increased signal intensity. MR is also able to detect plaques in the brainstem, cerebellum and within the cervical spinal cord. MR appears to be an important, non-invasive method for the diagnosis of Multiple Sclerosis and has proven to be diagnostically superior to CT, evoked potentials (EP) and CSF examination. In a selected group of 30 patients, with the whole battery of the relevant MS studies, MR was positive in 100%, CT in 33,3%, EP in 56% and CSF examination in 60%. In patients clinically presenting only with signs of spinal cord involvement or optic neuritis or when the clinical presentation is uncertain MR has proven to be a very useful diagnostic tool for diagnosis of MS by demonstrating unsuspected lesions in the cerebral hemispheres. (orig.)

Nuclear magnetic resonance gyroscope

International Nuclear Information System (INIS)

Grover, B.C.

1984-01-01

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

Magnetic resonance imaging of large and giant intracranial aneurysms

Energy Technology Data Exchange (ETDEWEB)

Matsumura, Kenichi; Saito, Akira; Nakasu, Yoko; Matsuda, Masayuki; Handa, Jyoji [Shiga University of Medical Science, Shiga (Japan); Todo, Giro

1990-06-01

Twelve large or giant intracranial aneurysms were studied with magnetic resonance (MR) imaging, and the findings were compared with those from computed tomographic (CT) scanning. Characteristic MR features of such aneurysms are: round, extra-axial mass with hypointensity rim; signal void, paradoxical enhancement, or even-echo rephasing due to blood flow; and laminated, eccentric thrombus with increased signal intensity when fresh, perianeurysmal hemorrhage occurs in the acute or subacute stage after aneurysmal rupture. MR imaging, however, often fails to identify or characterize the area of calcification. For the diagnosis of large or giant intracranial aneurysms, MR imaging is apparently superior to CT scanning in differentiating aneurysms from tumors, delineating the blood flow and intraluminal thrombus, and detecting the exact size of the aneurysm. It may also provide useful information concerning the growth mechanisms of aneurysms with or without thrombus formation. (author).

Importance of Proton Magnetic Resonance Spectroscopy in Diagnosis of Brain Tumors

International Nuclear Information System (INIS)

Polacek, H.; Zelenak, K.; Bittsansky, M.; Cisarikova, V.; DeRiggo, J.; Tichterova, R.

2011-01-01

Most brain tumors are routinely examined by CT and magnetic resonance (MR). MR plays a crucial role in the preoperative diagnosis and postoperative monitoring. In some cases, proton MR spectroscopy (MRS) provides additional diagnostic information to standard MR results. MRS analyzes important cerebral biochemical substances containing choline, N-acetylaspartate and more. We present a case of 42-year old patient with high-grade glioblastoma examined using MRS in addition to MR imaging before and after surgery. (author)

Magnetically coupled Fano resonance of dielectric pentamer oligomer

International Nuclear Information System (INIS)

Zhang, Fuli; Li, Chang; He, Xuan; Chen, Lei; Fan, Yuancheng; Zhao, Qian; Zhang, Weihong; Zhou, Ji

2017-01-01

We present magnetically induced Fano resonance inside a dielectric metamaterial pentamer composed of ceramic bricks. Unlike previous reports where different sizes of dielectric resonators were essential to produce Fano resonance, under external magnetic field excitation, central and outer dielectric bricks with identical sizes exhibit in-phase and out-of-phase magnetic Mie oscillations. An asymmetric line shape of Fano resonance along with enhanced group delay is observed due to the interference between the magnetic resonance of the central brick and the symmetric magnetic resonance of outer bricks. Besides, Fano resonance blueshifts with the increasing resonance of the smaller central brick. The thermal-dependent permittivity of ceramics allows Fano resonance to be reversibly tuned by 300 MHz when temperature varies by 60 °C. (paper)

Advances in mechanical detection of magnetic resonance

International Nuclear Information System (INIS)

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.

Magnetic resonance only workflow and validation of dose calculations for radiotherapy of prostate cancer

DEFF Research Database (Denmark)

Lübeck Christiansen, Rasmus; Jensen, Henrik R.; Brink, Carsten

2017-01-01

Background: Current state of the art radiotherapy planning of prostate cancer utilises magnetic resonance (MR) for soft tissue delineation and computed tomography (CT) to provide an electron density map for dose calculation. This dual scan workflow is prone to setup and registration error....... This study evaluates the feasibility of an MR-only workflow and the validity of dose calculation from an MR derived pseudo CT. Material and methods: Thirty prostate cancer patients were CT and MR scanned. Clinical treatment plans were generated on CT using a single 18 MV arc volumetric modulated arc therapy...... was successfully delivered to one patient, including manually performed daily IGRT. Conclusions: Median gamma pass rates were high for pseudo CT and proved superior to uniform density. Local differences in dose calculations were concluded not to have clinical relevance. Feasibility of the MR-only workflow...

Magnetic Resonance-Based Treatment Planning for Prostate Intensity-Modulated Radiotherapy: Creation of Digitally Reconstructed Radiographs

International Nuclear Information System (INIS)

Chen, Lili; Nguyen, Thai-Binh; Jones, Elan; Chen Zuoqun; Luo Wei; Wang Lu; Price, Robert A.; Pollack, Alan; Ma, C.-M. Charlie

2007-01-01

Purpose: To develop a technique to create magnetic resonance (MR)-based digitally reconstructed radiographs (DRR) for initial patient setup for routine clinical applications of MR-based treatment planning for prostate intensity-modulated radiotherapy. Methods and Materials: Twenty prostate cancer patients' computed tomography (CT) and MR images were used for the study. Computed tomography and MR images were fused. The pelvic bony structures, including femoral heads, pubic rami, ischium, and ischial tuberosity, that are relevant for routine clinical patient setup were manually contoured on axial MR images. The contoured bony structures were then assigned a bulk density of 2.0 g/cm 3 . The MR-based DRRs were generated. The accuracy of the MR-based DDRs was quantitatively evaluated by comparing MR-based DRRs with CT-based DRRs for these patients. For each patient, eight measuring points on both coronal and sagittal DRRs were used for quantitative evaluation. Results: The maximum difference in the mean values of these measurement points was 1.3 ± 1.6 mm, and the maximum difference in absolute positions was within 3 mm for the 20 patients investigated. Conclusions: Magnetic resonance-based DRRs are comparable to CT-based DRRs for prostate intensity-modulated radiotherapy and can be used for patient treatment setup when MR-based treatment planning is applied clinically

Investigation of magnetic interactions in sulfides by means of magnetic resonance

International Nuclear Information System (INIS)

Veen, G. van.

1978-01-01

Investigations have been designed to gather more information about magnetic pair interactions in sulfides by isomorphic substitution of the magnetic ions in suitable chosen diamagnetic host lattices and measurement of electron spin resonance of coupled pairs and of electron spin resonance or electron nuclear double resonance of the hyperfine interaction due to the nuclei of diamagnetic cations. The greater part of this thesis is devoted to preliminaries of magnetic resonance interpretation and sample selection and preparation. The measurements on the magnetically diluted compounds, which are described, only have an exploratory nature. (Auth.)

Magnetic resonance imaging the basics

CERN Document Server

Constantinides, Christakis

2014-01-01

Magnetic resonance imaging (MRI) is a rapidly developing field in basic applied science and clinical practice. Research efforts in this area have already been recognized with five Nobel prizes awarded to seven Nobel laureates in the past 70 years. Based on courses taught at The Johns Hopkins University, Magnetic Resonance Imaging: The Basics provides a solid introduction to this powerful technology. The book begins with a general description of the phenomenon of magnetic resonance and a brief summary of Fourier transformations in two dimensions. It examines the fundamental principles of physics for nuclear magnetic resonance (NMR) signal formation and image construction and provides a detailed explanation of the mathematical formulation of MRI. Numerous image quantitative indices are discussed, including (among others) signal, noise, signal-to-noise, contrast, and resolution. The second part of the book examines the hardware and electronics of an MRI scanner and the typical measurements and simulations of m...

Magnetic resonance tomography in confirmed multiple sclerosis

International Nuclear Information System (INIS)

Uhlenbrock, D.; Dickmann, E.; Beyer, H.K.; Gehlen, W.; Josef-Hospital, Bochum; Knappschafts-Krankenhaus Bochum

1985-01-01

The authors report on 21 cases of confirmed multiple sclerosis examined by both CT and magnetic resonance tomography. To safeguard the results, strict criteria were applied in accordance with the suggestions made by neurological work teams. Pathological lesons were seen in 20 patients; the MR image did not reveal anything abnormal in one case. On the average, 10.3 lesions were seen in the MR tomogram, whereas CT images showed on the average only 2.1 foci. The size and number of lesions in the MR tomogram were independent of the duration of the disease, the presented clinical symptoms, or the type of treatment at the time of examination. Evidently the sensitivity of MR tomography is very high in MS patients, but it has not yet been clarified to what extent this applies also to the specificity. Further research is mandatory. First experiences made by us show that lesions of a similar kind can also occur in diseases such as malignant lymphoma involving the brain, in vitamin B 12 deficiency syndrome, or encephalitis, and can become manifest in the MR tomogram. (orig.) [de

Does the Primary Imaging Modality-Computed Tomography or Magnetic Resonance Imaging-Influence Stroke Physicians' Certainty on Whether or Not to Give Thrombolysis to Randomized Acute Stroke Patients?

DEFF Research Database (Denmark)

Hansen, Christine Krarup; Christensen, Anders; Rodgers, Helen

2018-01-01

BACKGROUND: Door-to-needle time of 20 minutes to stroke patients with intravenous tissue plasminogen activator (iv-tPA) is feasible when computed tomography (CT) is used as first-line of brain imaging. Magnetic resonance imaging (MRI)-based assessment is more time-consuming but superior in detect......BACKGROUND: Door-to-needle time of 20 minutes to stroke patients with intravenous tissue plasminogen activator (iv-tPA) is feasible when computed tomography (CT) is used as first-line of brain imaging. Magnetic resonance imaging (MRI)-based assessment is more time-consuming but superior...

Moya - Moya syndrome: Diagnose by means of magnetic resonance

International Nuclear Information System (INIS)

Borrero Borrero, Leonidas; Henao Gomez, Liliana; Hernandez Castro, John Jairo

1997-01-01

We present a case of moya-moya syndrome diagnosed by means of study of magnetic resonance angiography (MRA) in an eight-year old patient with Seckel syndrome and progressive neurological deficit of several years, characterized by left hemi paresis and gait limitation as well as microcephalus. Previous imaging studies included cerebral CT (CCT) that showed several infarctions, without affecting a particular vascular territory. The MRA study was carried out in a 1.5 t system. Besides confirming the CCT findings, it demonstrated characteristic images of the moya - moya syndrome. This is the first case published in Colombia

[Magnetic resonance compatibility research for coronary mental stents].

Science.gov (United States)

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.

A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

Directory of Open Access Journals (Sweden)

K. Bartušek

2003-01-01

Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

The nuclear magnetic resonance well logging

International Nuclear Information System (INIS)

Zhang Yumin; Shen Huitang

2003-01-01

In this paper, the characteristic of the nuclear magnetic resonance logging is described at first. Then its development and its principle is presented. Compared with the nuclear magnetic resonance spectrometer, the magnet techniques is the first question that we must solve in the manufacture of the NMR well logging

Advances in magnetic and optical resonance

CERN Document Server

Warren, Warren S

1997-01-01

Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.

Non-cardiac findings on coronary computed tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Dewey, Marc; Schnapauff, Dirk; Teige, Florian; Hamm, Bernd

2007-01-01

Both multislice computed tomography (CT) and magnetic resonance imaging (MRI) are emerging as methods to detect coronary artery stenoses and assess cardiac function and morphology. Non-cardiac structures are also amenable to assessment by these non-invasive tests. We investigated the rate of significant and insignificant non-cardiac findings using CT and MRI. A total of 108 consecutive patients suspected of having coronary artery disease and without contraindications to CT and MRI were included in this study. Significant non-cardiac findings were defined as findings that required additional clinical or radiological follow-up. CT and MR images were read independently in a blinded fashion. CT yielded five significant non-cardiac findings in five patients (5%). These included a pulmonary embolism, large pleural effusions, sarcoid, a large hiatal hernia, and a pulmonary nodule (>1.0 cm). Two of these significant non-cardiac findings were also seen on MRI (pleural effusions and sarcoid, 2%). Insignificant non-cardiac findings were more frequent than significant findings on both CT (n = 11, 10%) and MRI (n = 7, 6%). Incidental non-cardiac findings on CT and MRI of the coronary arteries are common, which is why images should be analyzed by radiologists to ensure that important findings are not missed and unnecessary follow-up examinations are avoided. (orig.)

Non-cardiac findings on coronary computed tomography and magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Dewey, Marc; Schnapauff, Dirk; Teige, Florian; Hamm, Bernd [Charite-Universitaetsmedizin Berlin, Humboldt-Universitaet zu Berlin, Department of Radiology, Chariteplatz 1, P.O. Box 10098, Berlin (Germany)

2007-08-15

Both multislice computed tomography (CT) and magnetic resonance imaging (MRI) are emerging as methods to detect coronary artery stenoses and assess cardiac function and morphology. Non-cardiac structures are also amenable to assessment by these non-invasive tests. We investigated the rate of significant and insignificant non-cardiac findings using CT and MRI. A total of 108 consecutive patients suspected of having coronary artery disease and without contraindications to CT and MRI were included in this study. Significant non-cardiac findings were defined as findings that required additional clinical or radiological follow-up. CT and MR images were read independently in a blinded fashion. CT yielded five significant non-cardiac findings in five patients (5%). These included a pulmonary embolism, large pleural effusions, sarcoid, a large hiatal hernia, and a pulmonary nodule (>1.0 cm). Two of these significant non-cardiac findings were also seen on MRI (pleural effusions and sarcoid, 2%). Insignificant non-cardiac findings were more frequent than significant findings on both CT (n = 11, 10%) and MRI (n = 7, 6%). Incidental non-cardiac findings on CT and MRI of the coronary arteries are common, which is why images should be analyzed by radiologists to ensure that important findings are not missed and unnecessary follow-up examinations are avoided. (orig.)

Hepatocellular adenoma: findings at state-of-the-art magnetic resonance imaging, ultrasound, computed tomography and pathologic analysis

International Nuclear Information System (INIS)

Hussain, Shahid M.; Bos, Indra C. van den; Dwarkasing, Roy S.; Kuiper, Jan-Willem; Hollander, Jan den

2006-01-01

The purpose of this paper is to describe the most recent concepts and pertinent findings of hepatocellular adenomas, including clinical presentation, gross pathology and histology, pathogenesis and transformation into hepatocellular carcinoma (HCC), and imaging findings at ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging. (orig.)

Embroidered Coils for Magnetic Resonance Sensors

Directory of Open Access Journals (Sweden)

Michael I. Newton

2013-04-01

Full Text Available Magnetic resonance imaging is a widely used technique for medical and materials imaging. Even though the objects being imaged are often irregularly shaped, suitable coils permitting the measurement of the radio-frequency signal in these systems are usually made of solid copper. One problem often encountered is how to ensure the coils are both in close proximity and conformal to the object being imaged. Whilst embroidered conductive threads have previously been used as antennae in mobile telecommunications applications, they have not previously been reported for use within magnetic resonance. In this paper we show that an embroidered single loop coil can be used in a commercial unilateral nuclear magnetic resonance system as an alternative to a solid copper. Data is presented showing the determination of both longitudinal (T1 and effective transverse (T2eff relaxation times for a flat fabric coil and the same coil conformed to an 8 cm diameter cylinder. We thereby demonstrate the principles required for the wider use of fabric based conformal coils within nuclear magnetic resonance and magnetic resonance imaging.

Valuation for magnetic resonance of neuro tuberculosis

International Nuclear Information System (INIS)

Bolivar c, Guillermo; Delgado, Jorge A; Toro Nancy

1997-01-01

The increased incidence of neuro tuberculosis (NTB), due to the world epidemic of resistant strains and AIDS, has made of magnetic resonance (MR) imaging the study of choice for the early detection of lesions that lead the clinicians to an effective treatment. We present our experience with six cases of NTB, with meningoencephalic (4 cases), spinal, (1 case) and epidural (1 case) involvement. We identified basal arachnoiditis that was also seen on CT. Two cases demonstrated non-classifying tuberculomas, the spinal lesion consisted of casseifying tuberculoma that responded to treatment and disappeared on a follow up MR study. Epidural involvement consisted of Pott's disease with displacement and edema of the spinal cord. The differential diagnosis of these lesions includes mycoses, cysticercosis, sarcoidosis and leptomeningeal metastases

Magnetic resonance imaging of nasopharyngeal malignant tumors

International Nuclear Information System (INIS)

Sakakihara, Junji; Kanoh, Naoyuki; Hayakawa, Katsumi.

1988-01-01

Magnetic Resonance Imaging (MRI) was used in the examination of three patients with nasopharyngeal malignant tumor and cranial nerve symptoms. Coronal and saggital sections were very useful for determining skull base invasion. Its high contrast resolution enabled us to visualize several cranial nerves directly. Differentiation between tumor and effusion in the paranasal sinuses was easy especially in T2 weighted images. Bone destruction could also be detected as bone marrow replacement by tumor or as interruption of the black line of compact bone. Local relationships of tumor and large blood vessels were visualized by MRI without invasive contrast enhancing methods. Despite such advantages, in one patient whose symptoms were highly suggestive of cranial invasion, no cranial invasion was detected by CT or MRI. (author)

Pulsed-field gradient nuclear magnetic resonance study of transport properties of fluid catalytic cracking catalysts

Czech Academy of Sciences Publication Activity Database

Kortunov, P.; Vasenkov, S.; Kärger, J.; Fé Elía, M.; Perez, M.; Stöcker, M.; Papadopoulos, G. K.; Theodorou, D.; Drescher, B.; McElhiney, G.; Bernauer, B.; Krystl, V.; Kočiřík, Milan; Zikánová, Arlette; Jirglová, Hana; Berger, C.; Gläser, R.; Weitkamp, J.; Hansen, E. W.

2005-01-01

Roč. 23, č. 2 (2005), s. 233-237 ISSN 0730-725X Grant - others:TROCAT project - European Community(DE) G5RD-CT-2001-00520 Institutional research plan: CEZ:AV0Z40400503 Keywords : pulsed-field gradient * nuclear magnetic resonance * fluid catalytic cracking catalyst Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.361, year: 2005

Computed Tomography and Magnetic Resonance Imaging of Myoepitheliloma in the Soft Palate: A Case Report

International Nuclear Information System (INIS)

Lim, Hun Cheol; Yu, In Kyu; Park, Mi Ja; Jang, Dong Sik

2011-01-01

We report the appearance of myoepithelioma arising from minor salivary glands in the soft palate observed on computed tomography (CT) and magnetic resonance imaging (MRI). CT, the tumor was round with a smooth and partial lobulating contour, and slightly marginal contrast enhancement. On T1-weighted images, the mass had heterogeneous iso-signal intensity compared to the pharyngeal muscle. Additionally, the tumor had heterogeneously high T2 signal intensity with heterogeneously strong enhancement on the Gd-enhanced T1-weighted image. Radiologists should consider myoepithelioma in the radiological differential diagnosis of soft palate tumors.

Nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

Young, I.R.

1984-01-01

In a method of imaging a body in which nuclear magnetic resonance is excited in a region including part of the body, and the free induction decay signal is measured, a known quantity of a material of known nuclear magnetic resonance properties, for example a bag of water, is included in the region so as to enhance the measured free induction decay signal. This then reduces the generation of noise during subsequent processing of the signal. (author)

Magnetic resonance imaging. 1

International Nuclear Information System (INIS)

Wall, E.E. van der; Roos, A.A. de; Doornbos, J.; Dijkman, P.R.M. van; Matheijssen, N.A.A.; Laarse, A. van der; Krauss, X.H.; Blokland, J.A.k.; Manger Cats, V.; Voorthuisen, A.E. van; Bruschke, A.V.G.

1991-01-01

The cardiovascular applications of MRI in coronary artery disease have considerably increased in recent years. Although many applications overlap those of other more cost-effective techniques, such as echocardiography, radionuclide angiography, and CT, MRI offers unique features not shared by the conventional techniques. Technical advantages are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. This allows the accurate assessment of left ventricular mass and volume, the differentiation of infarcted tissue from normal myocardial tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. Also inducible myocardial ischemia using pharmacological stress (dipyramidole or dobutamine) may be assessed by magnetic resonance imaging. Future technical developments include real-time imaging and noninvasive visualization of the coronary arteries. These advantages will have a major impact on the application of MRI in coronary artery disease, potentially unsurpassed by other techniques and certainly justifying the expenses. Consequently, the clinical use of MRI for the detection of coronary artery disease largely depends on the progress of technical developments. (author). 134 refs.; 10 figs.; 2 tabs

Nuclear magnetic resonance diagnostic apparatus

International Nuclear Information System (INIS)

Sugimoto, H.

1985-01-01

Nuclear magnetic resonance diagnostic apparatus including a coil for generating a gradient field in a plane perpendicular to a static magnetic field, means for controlling the operation of the coil to rotationally shift in angular steps the gradient direction of the gradient field at an angle pitch of some multiple of the unit index angle through a plurality of rotations to assume all the shift positions of the gradient direction, a rough image reconstructor for reconstructing a rough tomographic image on the basis of nuclear magnetic resonance signals acquired during a rotation of the second gradient magnetic field, a rough image display for depicting the rough tomographic image, a final image reconstructor for reconstructing a final tomographic image on the basis of all nuclear magnetic resonance signals corresponding to all of the expected rotation shift positions acquired during a plurality of rotations and a final image display for depicting the final tomographic image

Nuclear magnetic resonance apparatus

International Nuclear Information System (INIS)

Lambert, R.

1991-01-01

In order to include the effect of a magnetic object in a subject under investigation, Nuclear Magnetic Resonance (NMR) apparatus is operable at more than one radio frequency (RF) frequency. The apparatus allows normal practice as far as obtaining an NMR response or image from a given nuclear species is concerned, but, in addition, interrogates the nuclear spin system at a frequency which is different from the resonance frequency normally used for the given nuclear species, as determined from the applied magnetic field. The magnetic field close to a magnetised or magnetisable object is modified and the given nuclear species gives a response at the different frequency. Thus detection of a signal at the frequency indicates the presence of the chosen nuclei close to the magnetised or magnetisable object. Applications include validation of an object detection or automatic shape inspection system in the presence of magnetic impurities, and the detection of magnetic particles which affect measurement of liquid flow in a pipe. (author)

Magnetic resonance imaging in neuro-Behcet's disease

International Nuclear Information System (INIS)

Kojima, Shigeyuki; Fukutake, Toshio; Hirayama, Keizo; Iwamoto, Itsuo

1987-01-01

In four patients with neuro-Behcet's disease, the findings of magnetic resonance imaging (MRI) were evaluated in comparison with the results of X-ray computed tomography (CT), especially for brainstem lesions. MRI was able to reveal brainstem lesions in three patients, in addition to lesions of basal ganglia, internal capsule and thalamus in the same patients. In contrast, X-ray CT demonstrated lesions of basal ganglia and internal capsule in only one patient, and it did not detect any brainstem lesions. Non-specific findings, including cerebral and brainstem atrophy, were revealed more clearly in inversion recovery images than in X-ray CT. Spin echo images were superior to inversion recovery images for detecting the lesions of demyelination, necrosis, gliosis and so on in neuro-Behcet's disease. The brainstem lesions visualized by MRI were situated in the regions of the basis pontis, cerebral peduncle and tectum of the midbrain. In neuro-Behcet's disease, the main pathological lesions are known occur in the ventral parts of the brainstem, but X-ray CT cannot always reveale these brainstem lesions because it produces bone artifacts. For this reason, the X-ray CT findings of neuro-Behcet's disease reported previously have been nonspecific cerebral or brainstem atrophy and decreased attenuations in the basal ganglia or subcortical white matter. Thus it is generally difficult to differentiate neuro-Behcet's disease from other intracranial lesions on the basis of the supratentorial X-ray CT findings. However, the above mentioned brainstem lesions visualized by MRI are consistent with the pathologically preferential site in neuro-Behcet's disease, and MRI can assist in the clinical diagnosis of neuro-Behcet's disease by demonstrating the brainstem lesions clearly, even when neurological involvement precedes the typical dermatologic and ophthalmologic manifestations. (author)

Nuclear magnetic resonance (NMR) imaging of Arnold-Chiari type I malformation with hydromyelia

International Nuclear Information System (INIS)

DeLaPaz, R.L.; Brady, T.J.; Buonanno, F.S.; New, P.F.; Kistler, J.P.; McGinnis, B.D.; Pykett, I.L.; Taveras, J.M.

1983-01-01

Saturation recovery nuclear magnetic resonance (NMR) images and metrizamide computed tomography (CT) scans were obtained in an adult patient with a clinical history suggestive of syringomyelia. Both NMR and CT studies showed low lying cerebellar tonsils. The CT study demonstrated central cavitation of the spinal cord from the midthoracic to midcervical levels but could not exclude an intramedullary soft tissue mass at the cervico-medullary junction. The NMR images in transverse, coronal, and sagittal planes demonstrated extension of an enlarged central spinal cord cerebrospinal fluid space to the cervico-medullary junction. This was felt to be strong evidence for exclusion of an intramedullary soft tissue mass and in favor of a diagnosis of Arnold-Chiari Type I malformation with hydromyelia. The noninvasive nature of spinal cord and cervico-medullary junction evaluation with NMR is emphasized

Spectrum of fluorodeoxyglucose-positron emission tomography/computed tomography and magnetic resonance imaging findings of ovarian tumors.

Science.gov (United States)

Kitajima, Kazuhiro; Ueno, Yoshiko; Maeda, Tetsuo; Murakami, Koji; Kaji, Yasushi; Kita, Masato; Suzuki, Kayo; Sugimura, Kazuro

2011-11-01

The purpose of this article is to review fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI) findings in a variety of benign, malignant, and borderline malignant ovarian tumors. It is advantageous to become familiar with the wide variety of FDG-PET/CT findings of this entity. Benign ovarian tumors generally have faint uptake, whereas endometriomas, fibromas, and teratomas show mild to moderate uptake. Malignant ovarian tumors generally have intense uptake, whereas tumors with a small solid component often show minimal uptake.

Magnetic resonance imaging of lumbar spine disc diseases. Frequency of false negatives; Imagerie par resonance magnetique pour pathologie discale lombaire. Frequence des faux-negatifs

Energy Technology Data Exchange (ETDEWEB)

Berthelot, J.M.; Maugars, Y.; Delecrin, Y.; Caillon, F.; Prost, A. [Hopital Hotel-Dieu de Nantes, 44 (France)

1995-10-01

Magnetic resonance imaging (MRI) has had an impressive impact on evaluation of degenerative diseases of the spine. Nevertheless, false negatives can occur on images involving lumbar discs. Degenerative disc diseases documented on discography and/or pathology examination of the discs can go unrecognized. Likewise sensitivity for the detection of protruding disc hernias is not totally satisfactory (20% false negatives). Finally, a magnetic resonance image visualizing displacement of the disc is not specific (10 to 15% false positives); images showing protrusion or hernia can be seen in 30% of asymptomatic patients. Although MRI gives slightly more information than other imaging techniques, false images do exist. Moreover, the usefulness of MRI to demonstrate disc disease in case of a negative CT-scan remains to be demonstrated. (authors). 26 refs.

Magnetic resonance and porous materials

International Nuclear Information System (INIS)

McDonald, P.; Strange, J.

1998-01-01

Mention the words magnetic resonance to your medical advisor and he or she will immediately think of a multi-million pound scanner that peers deep into the brain. A chemist, on the other hand, will imagine a machine that costs several hundred thousand pounds and produces high-resolution spectra for chemical analysis. Food technologists will probably think of a bench-top instrument for determining moisture content, while an oil prospector will envisage a device that can be operated several kilometres down an oil well. To a physicist the term is more likely to conjure up a mental picture of nuclear spins precessing in a magnetic field. These examples illustrate the diverse aspects of a phenomenon discovered by physicists over 50 years ago. Electron spin resonance was first discovered by Russian scientists, and nuclear magnetic resonance was discovered in the US shortly afterwards by Ed Purcell at Harvard University and Felix Bloch at Stanford University. Today, nuclear magnetic resonance (NMR) is the most widely used technique. Modern NMR machines are making it possible to probe microstructure and molecular movement in materials as diverse as polymers, cements, rocks, soil and foods. NMR allows the distribution of different components in a material to be determined with a resolution approaching 1μm, although the signal can be sensitive to even smaller lengthscales. In this article the authors describe how physicists are still developing magnetic resonance to exploit a range of new applications. (UK)

Magnetic resonance imaging by using nano-magnetic particles

Energy Technology Data Exchange (ETDEWEB)

Shokrollahi, H., E-mail: Shokrollahi@sutech.ac.ir [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Khorramdin, A. [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Isapour, Gh. [Department of Materials and Engineering, Hakim Sabzevari University (Iran, Islamic Republic of)

2014-11-15

Magnetism and magnetic materials play a major role in various biological applications, such as magnetic bioseparation, magnetic resonance imaging (MRI), hyperthermia treatment of cancer and drug delivery. Among these techniques, MRI is a powerful method not only for diagnostic radiology but also for therapeutic medicine that utilizes a magnetic field and radio waves. Recently, this technique has contributed greatly to the promotion of the human quality life. Thus, this paper presents a short review of the physical principles and recent advances of MRI, as well as providing a summary of the synthesis methods and properties of contrast agents, like different core materials and surfactants. - Highlights: • This paper studies the physics of MRI as a powerful diagnostic technique. • MRI uses the differentiation between healthy and pathological tissues. • The relaxation times can be shortened by the use of a magnetic contrast agent. • The magnetic nanoparticles act as contrast agents, helping to increase the resolution. • Different synthesis methods can influence the magnetic resonance behavior.

Ultrasound appearance of radiation-induced hepatic injury. Correlation with computed tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Garra, B.S.; Shawker, T.H.; Chang, R.; Kaplan, K.; White, R.D.

1988-01-01

The ultrasound findings in three cases of radiation-induced hepatic injury are described and compared with computed tomography and magnetic resonance imaging findings. Fatty infiltration of the liver was present in two of the cases in which concurrent chemotherapy was being administered. On ultrasound B-scans, the regions of radiation injury were hypoechoic relative to the remainder of the liver. This finding was more obvious in the patients with fatty livers. CT scans on the patients with fatty infiltrated livers showed higher attenuation in the irradiated region than in unexposed liver. In the patient where no fatty infiltration was present, the radiated section of liver had lower attenuation consistent with previous reports. Magnetic resonance imaging showed decreased signal in the exposed areas on T1 weighted images

Computed Tomography and Magnetic Resonance Features of Renal Ewing Sarcoma

International Nuclear Information System (INIS)

Ekram, T.; Elsayes, K.M.; Cohan, R.H.; Francis, I.R.

2008-01-01

Ewing sarcoma (ES) is a rare malignant tumor that primarily involves long and flat bones but can develop in almost any bone or soft tissue. ES accounts for 2.3-3.5% of tumors in patients under the age of 19, and is rarely found in the adult population. Sarcomas, in general, account for less than 1% of tumors in adults. Several reports of renal ES have been described in the pediatric population, but only a few cases have been described in the adult population. To the best of our knowledge, fewer than 10 cases of renal Ewing sarcoma in adults have been described in the English literature. None of these cases described the computed tomography (CT) and magnetic resonance imaging (MRI) features. We report a case of a 46-year-old woman, including CT and MRI characteristics

Magnetic resonance imaging of human cerebral infarction: Enhancement with Gd-DTPA

Energy Technology Data Exchange (ETDEWEB)

Imakita, S.; Nishimura, T.; Naito, H.; Yamada, N.; Yamamoto, K.; Takamiya, M.; Yamada, Y.; Sakashita, Y.; Minamikawa, J.; Kikuchi, H.

1987-09-01

Five patients (1 female and 4 males) with cerebral infarction of 4 h to 27 months duration were studied 9 times with magnetic resonance (MR) using Gd-DTPA. Spinecho (SE) MR images (MRI) were obtained before and after the administration of Gd-DTPA, and correlative CT scans were performed on the same day. In 2 cases, 4 h and 27 months after the ictus, there was no enhancement with Gd-DTPA. There was faint enhancement in 2 cases with cerebral infarction of about 24 h duration and obvious enhancement in all cases in the subacute stage. Compared with enhanced CT, MR using Gd-DTPA demonstrated more obvious enhancement of infarcted areas. MR enhancement using Gd-DTPA showed a gradual increase and the accumulated Gd-DTPA in infarcted areas slowly diffused to the periphery. MR enhancement with Gd-DTPA is similar to that of enhanced CT, but may be more sensitive in the detection of blood brain barrier breakdown.

Magnetic resonance imaging of the prostate

DEFF Research Database (Denmark)

Iversen, P; Kjaer, L; Thomsen, C

1988-01-01

Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate....

Magnetic resonance imaging of the prostate

DEFF Research Database (Denmark)

Iversen, P; Kjaer, L; Thomsen, C

1987-01-01

Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate....

Magnetic resonance imaging in the evaluation of medulloblastomas

International Nuclear Information System (INIS)

Tokimura, Hiroshi; Uetsuhara, Koichi; Komasaku, Ryuichiro; Kasamo, Shizuya; Asakura, Tetsuhiko

1989-01-01

Five patients with medulloblastomas were evaluated with Magnetic Resonance Imaging (MRI), and the results were compared with those of X-ray computed tomography (CT). On CT, medulloblastomas generally appeared as isodense or hyperdense masses and were enhanced uniformly with a contrast agent. On MRI, medulloblastomas appeared as low-intensity masses in T 1 -weighted images and as high-intensity masses in T 2 -weighted images. Moreover, the tumors were clearly differentiated from the surrounding tissue. In sagittal images, we could easily recognize the relation between the brainstem or the fourth ventiricle and the tumors. In spite of these merits, though, on MRI we could not detect the boundary between the tumors and the perifocal edema. In this point, we had to be dependent on CT. In one case, we could measure the T 1 value and the T 2 value both before and after irradiation. The T 2 value was markedly decreased after irradiation. Henceforth, the T 1 and T 2 values can be used to evaluate the effects of irradiation. Medulloblastomas are often disseminated through cerebrospinal fluid. We could detect this type of metastasis by means of the sagittal image on MRI. As has been mentioned above, MRI is very useful in diagnosing medulloblastomas and for the post-operative follow-up those tumors. (author)

Magnetic resonance of low dimensional magnetic solids

Energy Technology Data Exchange (ETDEWEB)

Gatteschi, D.; Ferraro, F.; Sessoli, R. (Florence Univ. (Italy))

1994-06-01

The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs.

Magnetic resonance of low dimensional magnetic solids

International Nuclear Information System (INIS)

Gatteschi, D.; Ferraro, F.; Sessoli, R.

1994-01-01

The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs

Magnetic resonance imaging of primary intracranial tumors: a review

International Nuclear Information System (INIS)

Holland, B.A.; Brant-Zawadzki, M.; Norman, D.; Newton, T.H.

1985-01-01

The experience in magnetic resonance (MR) imaging of primary intracranial neoplasia at University of California, San Francisco is reviewed. Seventy patients have been evaluated by MR and computerized tomography (CT). MR scans were performed using a multi-slice spin echo technique with a long pulse repetition time (TR = 2000 msec), and long echo sampling delay (TE = 56 msec). This method was most sensitive in differentiating normal gray and white matter and in detecting both cerebral edema and abnormal tissue with prolonged T 2 characteristics. More sensitive to slight alterations in normal tissue, MR may detect a focal lesion in cases in which CT shows only mass effect. Moreover, MR may demonstrate more thoroughly the extent of tumor infiltration and broaden the characterization of abnormal tissue. Posterior fossa and brainstem anatomy are invariably better depicted by MR. The major limitations of MR include its inability to detect foci of tumor calcification, demonstrate the severity of bone destruction, or reliably distinguish tumor nidus from surrounding edema

Magnetic resonance imaging in brain-stem tumors

International Nuclear Information System (INIS)

Nomura, Mikio; Saito, Hisazumi; Akino, Minoru; Abe, Hiroshi.

1988-01-01

Four patients with brain-stem tumors underwent magnetic resonance imaging (MRI) before and after radiotherapy. The brain-stem tumors were seen as a low signal intensity on T1-weighted images and as a high signal intensity on T2-weighted images. A tumor and its anatomic involvement were more clearly visualized on MRI than on cuncurrently performed CT. Changes in tumor before and after radiotherapy could be determined by measuring the diameter of tumor on sagittal and coronal images. This allowed quantitative evaluation of the reduction of tumor in association with improvement of symptoms. The mean T1 value in the central part of tumors was shortened in all patients after radiotherapy. The results indicate that MRI may assist in determining the effect of radiotherapy for brain-stem tumors. (Namekawa, K)

Arterial displacement by the tumor demonstrated by magnetic resonance CT

International Nuclear Information System (INIS)

Tsuchiya, Kazuhiro; Yoshikawa, Kohki; Machida, Tohru; Iio, Masahiro.

1985-01-01

MR-CT permits visualization of blood vessels non-invasively. Major blood vessels in scan slices are demonstrated as structures with low or no signal intensity. In this report, two cases with brain tumor and spinal tumor are presented in which arterial displacement by the tumor was visualized by MR-CT. MR-CT is considered to be an effective method in detecting blood vessel abnormalities. (author)

The nuclear magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Goyer, Ph.

1997-01-01

The spectroscopy of nuclear magnetic resonance constitutes a major analytical technique in biological and organic analysis. This technique appears now in the programme of preparatory classes and its teaching is developed in the second year of DEUG. The following article reviews on the nuclear magnetic resonance and on the possibilities it offers to bring to the fore the physico-chemical properties of molecules. (N.C.)

Advances in magnetic resonance 2

CERN Document Server

Waugh, John S

2013-01-01

Advances in Magnetic Resonance, Volume 2, features a mixture of experimental and theoretical contributions. The book contains four chapters and begins with an ambitious and general treatment of the problem of signal-to-noise ratio in magnetic resonance. This is followed by separate chapters on the interpretation of nuclear relaxation in fluids, with special reference to hydrogen; and various aspects of molecular theory of importance in NMR.

Magnetic resonance annual, 1988

International Nuclear Information System (INIS)

Kressel, H.Y.

1987-01-01

This book features reviews of high-resolution MRI of the knee, MRI of the normal and ischmeic hip, MRI of the heart, and temporomandibular joint imaging, as well as thorough discussion on artifacts in magnetic resonance imaging. Contributors consider the clinical applications of gadolinium-DTPA in magnetic resonance imaging and the clinical use of partial saturation and saturation recovery sequences. Timely reports assess the current status of rapid MRI and describe a new rapid gated cine MRI technique. Also included is an analysis of cerebrospinal fluid flow effects during MRI of the central nervous system

Magnetic resonance angiography

Science.gov (United States)

... Saunders; 2015:chap 17. Litt H, Carpenter JP. Magnetic resonance imaging. In: Cronenwett JL, Johnston KW, eds. Rutherford's Vascular Surgery . 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap ...

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed ... problems, medications, recent surgeries and allergies. The magnetic field is not harmful, but it may cause some ...

Cranial anatomy and detection of ischemic stroke in the cat by nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

Buonanno, F.S.; Pykett, I.L.; Kistler, J.P.; Vielma, J.; Brady, T.J.; Hinshaw, W.S.; Goldman, M.R.; Newhouse, J.H.; Pohost, G.M.

1982-01-01

Proton nuclear magnetic resonance (NMR) images of cat heads were obtained using a small, experimental imaging system. As a prelude to the study of experimental ischemic brain infarction, the normal cat head was imaged for identification of anatomical features. Images of one cat which had undergone ligation of the middle cerebral artery three weeks previously showed brain changes associated with chronic ischemic stroke and compared favorably with findings on computed tomography (CT). The NMR images have millimetric spatial resolution. NMR parameters inherent in the tissues provide intensity variations and are sufficiently sensitive to yield contrast resolution surpassing that of CT

Magnetic resonance imaging: hazard, risk and safety

International Nuclear Information System (INIS)

Narayan, Pradeep; Suri, S.; Singh, P.

2001-01-01

The hazard and risk associated with magnetic resonance imaging is a matter of concern. In 1982, the Food and Drug Administration (FDA), USA issued guidelines to Hospital's Investigational Review Board (IRBs) in 'Guidelines for Evaluating Electromagnetic Exposure Risks for Trials of Clinical Nuclear Magnetic Resonance (NMR)'. In 1997, the Berufsgenossenschaft (BG), professional association for precision engineering and electronics of Germany, in their preliminary proposal for safety limits extended their concerns on static magnetic field. Owing to both time varying and static magnetic fields applied in Magnetic Resonance Imaging (MRI) this became of immediate concern to user community to assess the potential hazard and risk associated with the NMR system

Magnetic resonance phenomena in dynamics of relativistic particles

International Nuclear Information System (INIS)

Ternov, I.M.; Bordovitsyn, V.A.

1987-01-01

A relativistic generalization of Rabi's formula for magnetic resonance is given. On this basis, we consider fast and slow passage through resonance. We define a magnetic resonance exterior field as usual, using unit vectors of a Cartesian coordinate system, a homogeneous magnetic field, and the amplitude of a rotating magnetic field. For the description of spin dynamics we use the Bargmann-Michel-Telegdi equation

Magnetic resonance imaging in sudden deafness

International Nuclear Information System (INIS)

Ramos, Hugo Valter Lisboa; Barros, Flavia Alencar; Penido, Norma de Oliveira; Souza, Ana Claudia Valerio de; Yamaoka, Wellington Yugo; Yamashita, Helio

2005-01-01

The etiology of sudden deafness can remain undetermined despite extensive investigation. This study addresses the value of magnetic resonance imaging in the analysis of sudden deafness patients.Study Design: transversal cohort.Material And Method: In a prospective study, 49 patients attended at otolaryngology emergency room of Federal University of Sao Paulo - Escola Paulista de Medicina, from April 2001 to May 2003, were submitted to magnetic resonance imaging.Results: Magnetic Resonance abnormalities were seen in 23 (46.9%) patients and revealed two tumors suggestive of meningioma, three vestibular schwannomas, thirteen microangiopathic changes of the brain and five (21.7%) pathological conditions of the labyrinth.Conclusion: Sudden deafness should be approached as a symptom common to different diseases. The presence of cerebellopontine angle tumors in 10.2% of our cases, among other treatable causes, justifies the recommendation of gadolinium-enhanced magnetic resonance use, not only to study the auditory peripheral pathway, but to study the whole auditory pathway including the brain. (author)

The history, economics, and politics of CT and MRI

International Nuclear Information System (INIS)

Evens, R.G.

1989-01-01

This paper presents the historical medical background in which computed tomography (CT) has been introduced. Early investigations in CT are discussed. The clinical development of both CT and magnetic resonance imaging (MRI) is described. The economics and efficacy of both techniques is discussed and compared

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

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Brain KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Brain What's in this article? What ...

Magnetic resonance signal moment determination using the Earth's magnetic field

KAUST Repository

Fridjonsson, Einar Orn; Creber, Sarah A.; Vrouwenvelder, Johannes S.; Johns, Michael L.

2015-01-01

We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth's magnetic field system.

Magnetic resonance signal moment determination using the Earth's magnetic field

KAUST Repository

Fridjonsson, Einar Orn

2015-03-01

We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth\\'s magnetic field system.

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... Magnetic Resonance Imaging (MRI) - Head Head and Neck Cancer Treatment Radiation Dose in X-Ray and CT Exams Contrast Materials Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation ...

Magnetic Resonance Imaging. Chapter 15

Energy Technology Data Exchange (ETDEWEB)

Leach, M. O. [The Institute of Cancer Research and The Royal Marsden Hospital, London (United Kingdom)

2014-09-15

In Chapter 14, the principles of nuclear magnetic resonance were presented, along with an introduction to image forming processes. In this chapter, magnetic resonance imaging (MRI) will be reviewed, beginning with the hardware needed and its impact on image quality. The acquisition processes and image reconstruction will be discussed, as well as the artefacts that are possible, with discussion of the important area of safety and bioeffects completing the chapter.

Force detection of nuclear magnetic resonance

International Nuclear Information System (INIS)

Rugar, D.; Zueger, O.; Hoen, S.; Yannoni, C.S.; Vieth, H.M.; Kendrick, R.D.

1994-01-01

Micromechanical sensing of magnetic force was used to detect nuclear magnetic resonance with exceptional sensitivity and spatial resolution. With a 900 angstrom thick silicon nitride cantilever capable of detecting subfemtonewton forces, a single shot sensitivity of 1.6 x 10 13 protons was achieved for an ammonium nitrate sample mounted on the cantilever. A nearby millimeter-size iron particle produced a 600 tesla per meter magnetic field gradient, resulting in a spatial resolution of 2.6 micrometers in one dimension. These results suggest that magnetic force sensing is a viable approach for enhancing the sensitivity and spatial resolution of nuclear magnetic resonance microimaging

Magnetic resonance imaging in the head and neck tumor diagnosis

Energy Technology Data Exchange (ETDEWEB)

Fujimoto, Yasuyuki; Igarashi, Masahito; Miyata, Mamoru; Sonoda, Tetsushi; Miyoshi, Shunji; Hiraide, Fumihisa; Morita, Mamoru; Tanaka, Osamu

1987-06-01

MRI (magnetic resonance imaging) is a new diagnostic technique that is being applied to study disease processes that involve the upper aero-digestive tract and cranial nerves of interest to otolaryngologist. Seventy four patients with head and neck tumor were enrolled to study the diagnostic efficacy of MRI in comparison with X-ray computed tomography (X-ray CT). Five cases of head and neck tumors were presented. Characteristic findings of MRI were discussed. T2 weighted images are very useful in the diagnosis of head and neck tumors. Tumors in the areas surrounded by bone tissue were clearly imaged without such artifacts as recognized in X-ray CT. Information from mutiplane imaging, especially from coronal and sagittal sections, made it easier to determine the type and extent of the lesion. High signal linear parts which are in the periphery of the tumor offer important information that no adhesion is present.

Principles of magnetic resonance imaging

International Nuclear Information System (INIS)

Mlynarik, V.; Tkac, I.; Srbecky, M.

1995-01-01

The aim of this review is to describe and explain the basic principles of magnetic resonance imaging. The first part of the text is devoted to the phenomenon of magnetic resonance (the interaction of RF magnetic field with the set of magnetic moments in the homogeneous magnetic field) and to relaxation processes. Then, the creation of MR image is described (slice selection, phase and frequency encoding of spatial information). The basic and the most frequently used techniques are explained (spin echo, gradient echo). The way the repetition and echo times influence the image quality and contrast (T1 or T2 weighing) is described. The part with the technical description of the MR equipment is included in the review. The MR imagination examination are compared with X-ray computer tomography technique

Magnetic resonance imaging in clinically-definite multiple sclerosis

International Nuclear Information System (INIS)

Noakes, J.B.; Herkes, G.K.; Frith, J.A.

1990-01-01

Forty-two patients with clinically-definite multiple sclerosis were examined by magnetic resonance imaging using a 1.5-T instrument. Magnetic resonance imaging detected an abnormality in 90% of patients. In four patients, no lesions were demonstrated. The number, size and site of the lesions by magnetic resonance imaging were compared with the patients' clinical status and other variables. The Kurtzke disability status scale score increased in patients with corpus callosum atrophy, brainstem and basal ganglia lesions, and correlated with the total number of lesions. No correlation was shown between the findings of magnetic resonance imaging and disease duration, age, sex or pattern-reversal visual-evoked potentials. The variety of magnetic resonance images that could be obtained in patients with clinically-definite multiple sclerosis is highlighted. 24 refs., 8 figs., 1 tab

Nuclear magnetic resonance method and apparatus

International Nuclear Information System (INIS)

Burl, M.; Young, I.R.

1984-01-01

A method and apparatus for determining the rate of flow of a liquid in a selected region of a body by nuclear magnetic resonance techniques are described. The method includes a sequence of applying a first magnetic pulse effective to excite nuclear magnetic resonance of a chosen nucleus within the liquid preferentially in a slice of the body which includes the selected region. A period of time (tsub(D)) is waited and then a second magnetic pulse is applied which is effective to excite nuclear magnetic resonance of the nuclei preferentially in the slice, and the free induction decay signal is measured. The whole sequence is repeated for different values of the period of time (tsub(D)). The variation in the value of the measured signal with tsub(D) is then related to the rate of flow of the liquid through the slice. (author)

Interaction of magnetic resonators studied by the magnetic field enhancement

Directory of Open Access Journals (Sweden)

Yumin Hou

2013-12-01

Full Text Available 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.

Nuclear Magnetic Resonance Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 1. Nuclear Magnetic Resonance Spectroscopy. Susanta Das. General Article Volume 9 Issue 1 January 2004 pp 34-49. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/01/0034-0049. Keywords.

Magnetic resonance imaging of the fetal brain.

Science.gov (United States)

Tee, L Mf; Kan, E Yl; Cheung, J Cy; Leung, W C

2016-06-01

This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

NMR magnetic field controller for pulsed nuclear magnetic resonance experiments

International Nuclear Information System (INIS)

Scheler, G.; Anacker, M.

1975-01-01

A nuclear magnetic resonance controller for magnetic fields, which can also be used for pulsed NMR investigations, is described. A longtime stability of 10 -7 is achieved. The control signal is generated by a modified time sharing circuit with resonance at the first side band of the 2 H signal. An exact calibration of the magnetic field is achieved by the variation of the H 1 - or of the time-sharing frequency. (author)

Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography.

Science.gov (United States)

Attenberger, Ulrike I; Morelli, John; Budjan, Johannes; Henzler, Thomas; Sourbron, Steven; Bock, Michael; Riffel, Philipp; Hernando, Diego; Ong, Melissa M; Schoenberg, Stefan O

2015-09-01

Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.

Resonance of magnetization excited by voltage in magnetoelectric heterostructures

Science.gov (United States)

Yu, Guoliang; Zhang, Huaiwu; Li, Yuanxun; Li, Jie; Zhang, Dainan; Sun, Nian

2018-04-01

Manipulation of magnetization dynamics is critical for spin-based devices. Voltage driven magnetization resonance is promising for realizing low-power information processing systems. Here, we show through Finite Element Method (FEM) simulations that magnetization resonance in nanoscale magnetic elements can be generated by a radio frequency (rf) voltage via the converse magnetoelectric (ME) effect. The magnetization dynamics induced by voltage in a ME heterostructures is simulated by taking into account the magnetoelastic and piezoelectric coupling mechanisms among magnetization, strain and voltage. The frequency of the excited magnetization resonance is equal to the driving rf voltage frequency. The proposed voltage driven magnetization resonance excitation mechanism opens a way toward energy-efficient spin based device applications.

Laser magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Ferrari, C.A.

1985-01-01

The technique of laser resonance magnetic resonance allows one to study the high-resolution spectroscopy of transient paramagnetic species, viz, atoms, radicals, and molecular ions. This article is a brief exposition of the method, describing the principles, instrumentation and applicability of the IR and FIR-LMR and shows results of HF + . (Author) [pt

FDG-PET in the diagnosis of neuropsychiatric Lupus erythematosus and comparison with computed tomography and magnetic resonance imaging. Einsatz der FDG-PET bei der Diagnostik des zentralnervoesen Lupus erythematodes und Vergleich mit CT und MRI

Energy Technology Data Exchange (ETDEWEB)

Stoppe, G [Medizinische Hochschule Hannover (Germany, F.R.). Neurologische Klinik mit Klinischer Neurophysiologie; Wildhagen, K [Medizinische Hochschule Hannover (Germany, F.R.). Abt. Immunologie und Transfusionsmedizin; Meyer, G J [Medizinische Hochschule Hannover (Germany, F.R.). Abt. Nuklearmedizin und Spezielle Biophysik; Schober, O [Muenster Univ. (Germany, F.R.). Klinik und Poliklinik fuer Nuklearmedizin

1989-10-01

Central nervous system involvement has been found in 30-75% of all cases of systemic lupus erythematosus (SLE). Up to now, clinical diagnosis is difficult and there are no markers for disease activity. We have compared cranial computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) using fluorodesoxyglucose (FDG) in two cases. FDG-PET is shown to be the most sensitive method demonstrating even reversible deficits and a better correlation with other neurological findings. MRI seems to be more sensitive than CT. A survey of the literature concerning imaging methods in neuropsychiatric SLE is given. The special problem of neuronal desactivation by antineuronal activity is discussed. (orig.).

The value of intraoperative ultrasound (IUS) examination for the visualization of metastatic cerebral lesions, compared with computed tomography (CT) and magnetic resonance (MRI)

International Nuclear Information System (INIS)

Tacikowska, M.; Szczerbicki, M.; Grzesiakowska, U.

2001-01-01

The purpose of this study is: 1. to assess the value of intraoperative ultrasonographic examination (IUSG) in confirming intraoperatively the presence of metastatic tumours detected preoperatively by computed tomography (CT) and magnetic resonance tomography (MRI), 2. to evaluate an accordance of the numbers, localization and dimensions of metastatic tumours recognized preoperatively (CT and MRI) with those shown by intraoperative USG, 3. to comparatively assess the images of metastatic tumours found in preoperative CT and MRI examinations and in intraoperative USG examinations. Sixteen patients were operated upon for metastatic intracranial tumours from various primary foci. All patients had diagnostic brain examinations before the operation: MRI and CT in 7 cases, only MRI in 3 cases, only CT in 6 cases. Intraoperative USG examination was done in all cases. Retrospective analysis included: 1. comparative assessment of the images of metastatic tumours in intraoperative USG versus preoperative MRI and CT findings, 2. analysis of the number, localization and dimensions of metastatic tumours detected preoperatively and in intraoperative USG examination. The comparison of the greatest dimensions of metastatic lesions measured in CT and MRI findings, and in intraoperative USG based on Student t test showed no statistically significant differences between the examinations performed, p=0.2449. No statistically significant difference were found either between the numbers of metastatic lesions detected by these methods, p=0.71830. In the analysis of the images of metastatic lesions in preoperative examinations, the non--homogenous foci with margin enhancement after administration of gadolinium or contrast medium, with inner area not enhanced (necrosis?) were found in 8 cases (10 foci lesions), and in USG in 6 cases (9 focal lesions). In one case (one lesion) USG showed that the tumour was hypo echogenic as a whole, without areola around it. Intraoperative USG examination

Waveguide volume probe for magnetic resonance imaging and spectroscopy

DEFF Research Database (Denmark)

2015-01-01

The present disclosure relates to a probe for use within the field of nuclear magnetic resonance, such as magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS)). One embodiment relates to an RF probe for magnetic resonance imaging and/or spectroscopy comprising a conductive...... non-magnetic hollow waveguide having an internal volume and at least one open end, one or more capacitors and at least a first conductive non-magnetic wire, wherein said first conductive wire connects at least one of said one or more capacitors to opposite walls of one open end of the waveguide...

Magnetic resonance (MR) in the diagnosis of pancreatic disease

International Nuclear Information System (INIS)

Anacker, H.; Rupp, N.; Reiser, M.; Technische Univ. Muenchen

1984-01-01

New methods of examination are measured in terms of the efficiency of their predecessors. The introduction of endoscopic retrograde cholangiopancreatography (ERCP) and computerised tomography (CT) constituted a turning point in the diagnosis of pancreatic disease. In this incipient stages as a clinical diagnostic method, the question is raised whether or not there is evidence that magnetic resonance (MR) can supplement, improve upon or replace the customary methods. It must, however, be taken into account that the technical development of MR is still in progress and that clinical experience with MR in the diagnosis of pancreatic disease, as in other areas, is still insufficient. At this point it is only possible to survey the trends. (orig.)

Magnetic resonance imaging of bone marrow disease in children

International Nuclear Information System (INIS)

Cohen, M.D.; Klatte, E.C.; Baehner, R.

1984-01-01

Seven children underwent magnetic resonance imaging (MRI) of the bone marrow: results showed that it is technically feasible to obtain good MR images of marrow in children. MR has detected abnormality in the bone marrow of a child who had metastatic neuroblastoma. The extent of abnormality in the femur correlated well with findings of a bone marrow isotope scan. In one child who had idiopathic aplastic anemia, diseased marrow could not be distinguished from normal marrow on MR images. MRI identified abnormality of the marrow in osteogenic sarcoma, and demonstrated change in response to chemotherapy. It displayed marrow spread of tumors as well as CT. MRI showed marrow abnormality in four children who had leukemia

Observation of ferromagnetic resonance in a microscopic sample using magnetic resonance force microscopy

International Nuclear Information System (INIS)

Zhang, Z.; Hammel, P.C.; Wigen, P.E.

1996-01-01

We report the observation of a ferromagnetic resonance signal arising from a microscopic (∼20μmx40μm) particle of thin (3μm) yttrium iron garnet film using magnetic resonance force microscopy (MRFM). The large signal intensity in the resonance spectra suggests that MRFM could become a powerful microscopic ferromagnetic resonance technique with a micron or sub-micron resolution. We also observe a very strong nonresonance signal which occurs in the field regime where the sample magnetization readily reorients in response to the modulation of the magnetic field. This signal will be the main noise source in applications where a magnet is mounted on the cantilever. copyright 1996 American Institute of Physics

Computed Tomography (CT) -- Sinuses

Medline Plus

Full Text Available ... of any kind, unlike MRI. CT imaging provides real-time imaging, making it a good tool for guiding ... information is needed to determine the extent of soft tissue of the tumor, magnetic resonance imaging (MRI) ...

Proton magnetic resonance spectroscopy and single photon emission CT in patients with olivopontocerebellar atrophy

International Nuclear Information System (INIS)

Ikuta, Naomi

1998-01-01

Using proton magnetic resonance spectroscopy ( 1 H-MRS) and single photon emission CT (SPECT), the cerebellum of patients with olivopontocerebellar atrophy (OPCA) and of age-matched control subjects was studied. A spectrum was collected from a 27 cm 3 (3 x 3 x 3 cm) voxel in the cerebellum containing white and gray matters in order to measure the distribution and relative signal intensities of N-acetylaspartate (NAA), creatine (Cre) and choline (Cho). In the cerebellum of the patients with OPCA, mean NAA/Cre ratios for OPCA patients were significantly decreased compared with normal control subjects (OPCA, 1.01±0.247; controls, 1.526±0.144: p<0.001). Mean NAA/Cho ratios for OPCA patients were slightly decreased (OPCA, 1.285±0.228; controls 1.702±0.469: p<0.06). Cho/Cre ratios valued in the cerebellum of OPCA patients were not significantly different from those in normal controls (OPCA, 0.793±0.186; controls, 0.946±0.219). The ratio of RI count in the cerebellum to that in the occipital lobe was significantly decreased in OPCA patients (OPCA, 0.947±0.096; controls, 1.06±0.063: p<0.01). Cerebellar signs were assessed including gait ataxia, limb ataxia, dysarthria, saccadic pursuit, and nystagmus separately or in combination. In patients with more severe ataxic gait and dysarthria, MRS revealed slightly lowered NAA/Cre ratio. There was no significant correlation between NAA/Cre ratio and severity of other clinical signs. The MRS and SPECT findings give a confirmative evidence of hypofunction in cerebellum of patients with OPCA. (author)

Quantitative Assessment of Liver Fat with Magnetic Resonance Imaging and Spectroscopy

Science.gov (United States)

Reeder, Scott B.; Cruite, Irene; Hamilton, Gavin; Sirlin, Claude B.

2011-01-01

Hepatic steatosis is characterized by abnormal and excessive accumulation of lipids within hepatocytes. It is an important feature of diffuse liver disease, and the histological hallmark of non-alcoholic fatty liver disease (NAFLD). Other conditions associated with steatosis include alcoholic liver disease, viral hepatitis, HIV and genetic lipodystrophies, cystic fibrosis liver disease, and hepatotoxicity from various therapeutic agents. Liver biopsy, the current clinical gold standard for assessment of liver fat, is invasive and has sampling errors, and is not optimal for screening, monitoring, clinical decision making, or well-suited for many types of research studies. Non-invasive methods that accurately and objectively quantify liver fat are needed. Ultrasound (US) and computed tomography (CT) can be used to assess liver fat but have limited accuracy as well as other limitations. Magnetic resonance (MR) techniques can decompose the liver signal into its fat and water signal components and therefore assess liver fat more directly than CT or US. Most magnetic resonance (MR) techniques measure the signal fat-fraction (the fraction of the liver MR signal attributable to liver fat), which may be confounded by numerous technical and biological factors and may not reliably reflect fat content. By addressing the factors that confound the signal fat-fraction, advanced MR techniques measure the proton density fat-fraction (the fraction of the liver proton density attributable to liver fat), which is a fundamental tissue property and a direct measure of liver fat content. These advanced techniques show promise for accurate fat quantification and are likely to be commercially available soon. PMID:22025886

The particle concentration effect on magnetic resonance linewidth for magnetic liquids with chain aggregates

International Nuclear Information System (INIS)

Marin, C.N.

2002-01-01

Based on the assumption of particle chains formation within a magnetic liquid, computer simulation of the magnetic resonance line is presented. The dependence on particle concentration within a magnetic liquid of magnetic resonance linewidth is analyzed. The computer simulation demonstrates that the particles chaining has an important effect on the enlargement of the magnetic resonance line. Increasing the particle concentration within magnetic liquid leads to an increase in the linewidth. The agreement with some experimental findings is discussed

Computed tomography and magnetic resonance for the advanced imaging of the normal nasal cavity and paranasal sinuses of the koala (Phascolarctos cinereus).

Science.gov (United States)

Bercier, Marjorie; Alexander, Kate; Gorow, April; Pye, Geoffrey W

2014-12-01

The objective of this study is to describe computed tomography (CT) and magnetic resonance (MR) for the cross-sectional imaging of the normal anatomy of the nasal cavity and paranasal sinuses of the koala (Phascolarctos cinereus), to provide reference figures for gross anatomy with corresponding CT and MR images and to compare the features of the nasal cavity and paranasal sinuses of the normal koala with that reported in other domestic species. Advanced imaging can be used to aid in diagnosis, to plan surgical intervention, and to monitor therapeutic responses to diseases of the nasal passages in koalas. One clinically normal koala was anesthetized twice for the separate acquisition of dorsal CT scan images and transverse, dorsal, and sagittal MR images of its nasal cavity and paranasal sinuses. Sagittal and transverse CT planes were reformatted. Three fresh koala skulls were also transected in one of each transverse, sagittal, and dorsal planes and photographed. The CT and MR images obtained were matched with corresponding gross anatomic images and the normal bone, tissues and airway passages were identified. All anatomic structures were readily identifiable on CT, magnetic resonance imaging (MRI), and gross images. CT and MRI are both valuable diagnostic tools for imaging the nasal cavities and paranasal sinuses of koalas. Images obtained from this project can be used as baseline references for future comparison with diseased koalas to help with diagnosis, surgical intervention, and response to therapy.

Analysis of systemic lupus erythematosus (SLE) involving the central nervous system by magnetic resonance imaging (MRI)

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Kimihiro; Hara, Masako; Nakajima, Shinji and others

1989-04-01

Involvement of the central nervous system (CNS) commonly occurs in systemic lupus erythematosus (SLE). But definitive diagnosis remains difficult even with computed tomography (CT). In this study, we used the recently developed technique, magnetic resonance imaging (MRI) for CNS lupus and compared it with CT scans. CT was performed with a General Electric 8800 CT/T scanner. MRI was performed using a Mitsubishi Electric MMI-150 S. Ten patients with CNS lupus were divided into 3 groups. Group I included 4 cases with neurological manifestations alone. All lesions seen on CT were also detected by MRI, with greater clarity and extent. Furthermore, MRI depicted several microinfarcts in white matter without symptoms. Group II included 5 cases with psychiatric features alone. MRI detected a thalamic microinfarct in only one case while CT showed no abnormality in all cases. Group III included 1 case with both neurological and psychiatric symptoms. MRI demonstrated a small infarct of midbrain corresponding with neurological symptoms, more clearly than CT. Therefore MRI demonstrates the degree of brain involvement in SLE more accurately than CT. (author).

Analysis of systemic lupus erythematosus (SLE) involving the central nervous system by magnetic resonance imaging (MRI)

International Nuclear Information System (INIS)

Suzuki, Kimihiro; Hara, Masako; Nakajima, Shinji

1989-01-01

Involvement of the central nervous system (CNS) commonly occurs in systemic lupus erythematosus (SLE). But definitive diagnosis remains difficult even with computed tomography (CT). In this study, we used the recently developed technique, magnetic resonance imaging (MRI) for CNS lupus and compared it with CT scans. CT was performed with a General Electric 8800 CT/T scanner. MRI was performed using a Mitsubishi Electric MMI-150 S. Ten patients with CNS lupus were divided into 3 groups. Group I included 4 cases with neurological manifestations alone. All lesions seen on CT were also detected by MRI, with greater clarity and extent. Furthermore, MRI depicted several microinfarcts in white matter without symptoms. Group II included 5 cases with psychiatric features alone. MRI detected a thalamic microinfarct in only one case while CT showed no abnormality in all cases. Group III included 1 case with both neurological and psychiatric symptoms. MRI demonstrated a small infarct of midbrain corresponding with neurological symptoms, more clearly than CT. Therefore MRI demonstrates the degree of brain involvement in SLE more accurately than CT. (author)

76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

Science.gov (United States)

2011-09-20

...] Magnetic Resonance Imaging Safety; Public Workshop AGENCY: Food and Drug Administration, HHS. ACTION... announcing a public workshop entitled: ``Magnetic Resonance Imaging (MRI) Safety Public Workshop.'' The purpose of the public workshop is to discuss factors affecting the safe use of magnetic resonance imaging...

Functional magnetic resonance imaging of the primary motor cortex ...

Indian Academy of Sciences (India)

Unknown

Abbreviations used: BOLD, Blood oxygenation level dependent; CBF, cerebral blood flow; fMRI, functional magnetic resonance imaging; EPI, eco-planar imaging; FOV, field of view; MRI, Magnetic resonance imaging; MRS, magnetic resonance spectroscopy;. PET, position emission tomography; rCBF, regional cerebral ...

Magnetic resonance angiography for the head and neck region

International Nuclear Information System (INIS)

Aschenbach, R.; Esser, D.

2004-01-01

Magnetic resonance angiography is a noninvasive method in vascular imaging using noncontrast- enhanced and contrast-enhanced techniques. The contrast media used in contrast- enhanced magnetic resonance angiography are different from the X-ray contrast media and do not affect the thyroid gland or renal function. In detecting hypervascularized lesions in the head and neck, contrast-enhanced magnetic resonance angiography is the method of choice, which provides an acceptable quality in comparison to digital subtraction angiography. Future developments in magnetic resonance imaging techniques will cause a wider use of magnetic resonance angiography, especially in head and neck imaging. Digital subtraction angiography should therefore only be used in problem cases and for preoperative embolization [de

Magnetic resonance spectroscopy of traumatic brain in SD rats model

International Nuclear Information System (INIS)

Li Ke; Li Yangbin; Li Zhiming; Huang Yong; Li Bin; Lu Guangming

2009-01-01

Objective: To assess the value and prospect of magnetic resonance spectroscopy (MRS) in early diagnosis of traumatic brain with traumatic brain model in SD rats. Methods: Traumatic brain modal was established in 40 male SD rats utilizing a weigh-drop device, and MRS was performed before trauma and 4,8,24 and 48 hours after trauma. The ratio of N-acetylaspartate/creatine (NAA/Ct) and choline/creatine (Cho/Cr) were calculated and compared with pathological findings respectively. Results: Axonal changes were confirmed in microscopic study 4 hours after injury. The ratio of NAA/Ct decreased distinctly at 4 hours after trauma, followed by a steadily recover at 8 hours, and no significant change from 24h to 48h. There was no significant change in the ratio of Cho/Cr before and after trauma. Conclusion: MRS can be used to monitor the metabolic changes of brain non-invasively. MRS could play a positive role in early diagnosis, prognosis and follow-up of traumatic brain. (authors)

Sequential changes of sodium magnetic resonance images after cerebral hemorrhage

International Nuclear Information System (INIS)

Shimizu, T.; Naritomi, H.; Kuriyama, Y.; Sawada, T.

1992-01-01

Four patients with cerebral hemorrhage were examined serially from the acute to chronic phase by 1 H magnetic resonance imaging (MRI), 23 Na MRI and computed tomography (CT). At 1-2 days after bleeding, the 23 Na image revealed no visible signal change in the area of hemorrhage, although CT and 1 H images clearly demonstrated the existence of a hematoma in the thalamus or putamen. At 4-7 days after the hemorrhage, the 23 Na images began to exhibit a small increase in signal intensity at the hematoma site, while at 2-3 weeks, a marked increase in 23 Na signal intensity was observed. These findings suggest that the hematoma consisted mainly of a corpuscular component, with a low Na + concentration, with little serum component. 23 Na MRI appears to provide important information for understanding the evoluation of cerebral hemorrhage and for estimating the viability of cells, although its value for diagnosis may not be great. (orig./GDG)

Single voxel magnetic resonance spectroscopy in distinguishing ...

African Journals Online (AJOL)

Objective: Assess diagnostic utility of combined magnetic resonance imaging and magnetic resonance spectroscopy (MRI, MRS) in differentiating focal neoplastic lesions from focal non- neoplastic (infective or degenerative) brain lesions. Design: Descriptive, analytical - prospective study. Setting: The Aga Khan University ...

Your Radiologist Explains Magnetic Resonance Angiography (MRA)

Medline Plus

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

Contrast agents in magnetic resonance imaging

International Nuclear Information System (INIS)

Karadjian, V.

1987-01-01

The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes [fr

Magnetic resonance: discovery, investigations, and applications

International Nuclear Information System (INIS)

Kessenikh, Aleksandr V

2009-01-01

The history of the development of the theoretical ideas and experimental methods of magnetic resonance, as well as the applications of these methods in modern natural science, technology, and medicine, are outlined, with allowance for the contribution of Russian researchers. An assessment of some promising trends of studies and applications of magnetic resonance is given. (from the history of physics)

Reducing Field Distortion in Magnetic Resonance Imaging

Science.gov (United States)

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

Pulse sequences for contrast-enhanced magnetic resonance imaging

International Nuclear Information System (INIS)

Graves, Martin J.

2007-01-01

The theory and application of magnetic resonance imaging (MRI) pulse sequences following the administration of an exogenous contrast agent are discussed. Pulse sequences are categorised according to the contrast agent mechanism: changes in proton density, relaxivity, magnetic susceptibility and resonant frequency shift. Applications in morphological imaging, magnetic resonance angiography, dynamic imaging and cell labelling are described. The importance of optimising the pulse sequence for each application is emphasised

Magnetic field induced incommensurate resonance in cuprate superconductors

International Nuclear Information System (INIS)

Zhang Jingge; Cheng Li; Guo Huaiming; Feng Shiping

2009-01-01

The influence of a uniform external magnetic field on the dynamical spin response of cuprate superconductors in the superconducting state is studied based on the kinetic energy driven superconducting mechanism. It is shown that the magnetic scattering around low and intermediate energies is dramatically changed with a modest external magnetic field. With increasing the external magnetic field, although the incommensurate magnetic scattering from both low and high energies is rather robust, the commensurate magnetic resonance scattering peak is broadened. The part of the spin excitation dispersion seems to be an hourglass-like dispersion, which breaks down at the heavily low energy regime. The theory also predicts that the commensurate resonance scattering at zero external magnetic field is induced into the incommensurate resonance scattering by applying an external magnetic field large enough

Magnetic resonance imaging diagnosis of the locus of lesions in neuro-ophthalmological diseases

International Nuclear Information System (INIS)

Nobuto, Keiko; Oka, Tomomi; Ishiguro, Mami; Ohnishi, Tohru; Fukushima, Masahiro; Tsutsui, Jun

1989-01-01

Seven patients with neuro-opthalmological diseases were examined by X-ray computed tomography (CT) and magnetic resonance imaging (MRI), and the application of the latter in these diseases was studied. The cases included one each of rhinogenous optic neuropathy with mucocele in the ethnoid sinus, pituitary adenoma, multiple sclerosis, multiple cerebral infarction, hemangioma in the pontine region, one-and-a-half syndrome, and oculomotor nerve palsy with midbrain infarction. We were able to diagnose the pituitary adenoma and the multiple cerebral infarction by both MRI and CT, but in the other cases the lesions could not be detected by CT and some smaller lesions were visualized by MRI alone. These smaller lesions were in the paranasal sinus and brain stem, where CT diagnosis is difficult because of bone artifacts. The absence of bone artifacts was one of the advantages of MRI as evaluated in this study. Poor demonstration of calcification and bones, however, seemed to be a weak point. Our study showed MRI to be effective in examining neuro-ophthalmological diseases. (author)

Magnetic resonance imaging diagnosis of the locus of lesions in neuro-ophthalmological diseases

Energy Technology Data Exchange (ETDEWEB)

Nobuto, Keiko; Oka, Tomomi; Ishiguro, Mami; Ohnishi, Tohru; Fukushima, Masahiro; Tsutsui, Jun (Kawasaki Medical School, Kurashiki, Okayama (Japan))

1989-12-01

Seven patients with neuro-opthalmological diseases were examined by X-ray computed tomography (CT) and magnetic resonance imaging (MRI), and the application of the latter in these diseases was studied. The cases included one each of rhinogenous optic neuropathy with mucocele in the ethnoid sinus, pituitary adenoma, multiple sclerosis, multiple cerebral infarction, hemangioma in the pontine region, one-and-a-half syndrome, and oculomotor nerve palsy with midbrain infarction. We were able to diagnose the pituitary adenoma and the multiple cerebral infarction by both MRI and CT, but in the other cases the lesions could not be detected by CT and some smaller lesions were visualized by MRI alone. These smaller lesions were in the paranasal sinus and brain stem, where CT diagnosis is difficult because of bone artifacts. The absence of bone artifacts was one of the advantages of MRI as evaluated in this study. Poor demonstration of calcification and bones, however, seemed to be a weak point. Our study showed MRI to be effective in examining neuro-ophthalmological diseases. (author).

Nuclear magnetic resonance imaging of the kidney

International Nuclear Information System (INIS)

Hricak, H.; Crooks, L.; Sheldon, P.; Kaufman, L.

1983-01-01

The role of nuclear magnetic resonance (NMR) imaging of the kidney was analyzed in 18 persons (6 normal volunteers, 3 patients with pelvocaliectasis, 2 with peripelvic cysts, 1 with renal sinus lipomatosis, 3 with renal failure, 1 with glycogen storage disease, and 2 with polycystic kidney disease). Ultrasound and/or computed tomography (CT) studies were available for comparison in every case. In the normal kidney distinct anatomical structures were clearly differentiated by NMR. The best anatomical detail ws obtained with spin echo (SE) imaging, using a pulse sequence interval of 1,000 msec and an echo delay time of 28 msec. However, in the evaluation of normal and pathological conditions, all four intensity images (SE 500/28, SE 500/56, SE 1,000/28, and SE 1,000/56) have to be analyzed. No definite advantage was found in using SE imaging with a pulse sequence interval of 1,500 msec. Inversion recovery imaging enhanced the differences between the cortex and medulla, but it had a low signal-to-noise level and, therefore, a suboptimal overall resolution. The advantages of NMR compared with CT and ultrasound are discussed, and it is concluded that NMR imaging will prove to be a useful modality in the evaluation of renal disease

Magnetic resonance imaging in the diagnosis of pancreatic diseases

International Nuclear Information System (INIS)

Yamaguchi, Taketo; Ebara, Masaaki; Saisho, Hiromitsu

1987-01-01

Fifty patients with various pancreatic diseases and 22 without pancreatic disease were studied by a magnetic resonance imaging (MRI) to compare its diagnostic capability with that by an X-ray CT scan. To differentiate pancreas clearly from the bowel, an iron solution was orally administered as contrast medium, resulting in a usefullness, especially to differentiate the head of the pancreas from the bowel. The head of the pancreas could be identified in 89 % after iron solution but only in 62 % without it. MRI was inferior to CT in terms of visualization of the pancreatic duct and pancreatic stones, but was superior in a visualization of vessels around the pancreas. MRI was considered to be useful for a detection of carcinoma infiltrating to vessels. Pancreatic carcinoma was differentiated from chronic pancreatitis in terms of a local enlargement and disappearance of fat around the pancreas shown on MRI findings. The present results also showed statistically significant differences in T 1 relaxation times among normal pancreas, chronic pancreatitis and pancreatic carcinoma, suggesting a useful marker in the differential diagnosis of pancreatic diseases. (author)

Inhalant-Abuse Myocarditis Diagnosed by Cardiac Magnetic Resonance.

Science.gov (United States)

Dinsfriend, William; Rao, Krishnasree; Matulevicius, Susan

2016-06-01

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.

Magnetic resonance imaging- physical principles and clinical application

International Nuclear Information System (INIS)

Tavri, Omprakash J.

1996-01-01

The advances in equipment and knowledge related to radiology are occurring at an astonishingly rapid rate. On November 8, 1895, William Conrad Roentgen discovered x-rays. In 1972, Godfrey Hounsfield and George Ambrose introduced computec tomography at a meeting of the British Institute of Radiology. In the same year, Paul Lauterbur published the idea of spatially resolving nuclear magnetic resonance samples, naming it zeugmatography. In 1977, Waldo Hinshaw and co-workers published a magnetic resonance image of a human hand and wrist, and by 1981 several centres were obtaining clinical magnetic resonance (MR) images. In a very short time, magnetic resonance imaging (MRI) has gained acceptance as a clinically useful imaging tool. (author)

Low field magnetic resonance imaging

Science.gov (United States)

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.

Magnetic Resonance Imaging (MRI) -- Head

Medline Plus

Full Text Available ... by the interpreting radiologist. Frequently, the differentiation of abnormal (diseased) tissue from normal tissues is better with ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

Tuning Coler Magnetic Current Apparatus with Magneto-Acoustic Resonance

Science.gov (United States)

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.

Migraine and magnetic resonance spectroscopy

DEFF Research Database (Denmark)

Younis, Samaira; Hougaard, Anders; Vestergaard, Mark B.

2017-01-01

Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation in the meth......Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation...

Magnetic resonance imaging of the brain in congenital cytomegalovirus infection

International Nuclear Information System (INIS)

Boesch, C.; Issakainen, J.; Kewitz, G.; Kikinis, R.; Martin, E.; Boltshauser, E.

1989-01-01

The children (age 2 months to 8 years) with a congenital cytomegalovirus (CMV) infection were studied by magnetic resonance imaging (MRI) using a 2.35 Tesla magnet. CMV infection was confirmed by serological investigations and virus culture in the neonatal period. Nine children had severe mental retardation and cerebral palsy, 1 patient suffered from microcephaly, ataxia and deafness. The cranial MRI examination showed the following abnormalities (N): Dilated lateral ventricles (10) and subarachnoid space (8), oligo/pacgyria (8), delayed/pathological myelination (7), paraventricular cysts (6), intra-cerebral calcification (1). This lack of sensitivity for calcification is explainable by the basic principles of MRI. The paraventricular cystic lesions were adjacent ot the occipital horns of the lateral ventricles and separated only by a thin membrane. This finding might represent a 'new sign' for congenital CMV infection in MRI examinations, being characteristic but nevertheless nonspecific, like calcification in CT. (orig.)

Improved longitudinal length accuracy of gross tumor volume delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma

International Nuclear Information System (INIS)

Hou, Dong-Liang; Shi, Gao-Feng; Gao, Xian-Shu; Asaumi, Junichi; Li, Xue-Ying; Liu, Hui; Yao, Chen; Chang, Joe Y

2013-01-01

To analyze the longitudinal length accuracy of gross tumor volume (GTV) delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma (SCC). Forty-two patients from December 2011 to June 2012 with esophageal SCC who underwent radical surgery were analyzed. Routine computed tomography (CT) scan, T2-weighted MRI and diffusion weighted magnetic resonance imaging (DWI) were employed before surgery. Diffusion-sensitive gradient b-values were taken at 400, 600, and 800 s/mm 2 . Gross tumor volumes (GTV) were delineated using CT, T2-weighted MRI and DWI on different b-value images. GTV longitude length measured using the imaging modalities listed above was compared with pathologic lesion length to determine the most accurate imaging modality. CMS Xio radiotherapy planning system was used to fuse DWI scans and CT images to investigate the possibility of delineating GTV on fused images. The differences between the GTV length according to CT, T2-weighted MRI and pathology were 3.63 ± 12.06 mm and 3.46 ± 11.41 mm, respectively. When the diffusion-sensitive gradient b-value was 400, 600, and 800 s/mm 2 , the differences between the GTV length using DWI and pathology were 0.73 ± 6.09 mm, -0.54 ± 6.03 mm and −1.58 ± 5.71 mm, respectively. DWI scans and CT images were fused accurately using the radiotherapy planning system. GTV margins were depicted clearly on fused images. DWI displays esophageal SCC lengths most precisely when compared with CT or regular MRI. DWI scans fused with CT images can be used to improve accuracy to delineate GTV in esophageal SCC

Rotational characteristics in the resonance state of the HTSC-permanent magnet hybrid magnetic bearing

Energy Technology Data Exchange (ETDEWEB)

Morii, Y.; Sukedai, M. [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Ohashi, S., E-mail: ohashi@kansai-u.ac.jp [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)

2011-11-15

The hybrid magnetic bearing has been developed. In the hybrid system, effect of the pinning force becomes smaller. Influence of the vibration and the gradient angle in the resonance state is large. The resonance frequency becomes small in the hybrid bearing system. The hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC) has been developed. Repulsive force of the permanent magnet is introduced to increase the load weight of the magnetic bearing. Effect of the hybrid system has been shown. In this paper, influence of the hybrid system on the dynamic characteristics of the rotor is studied. The rotational characteristics in the mechanical resonance state are studied, and the equivalent magnetic spring coefficient is estimated from the experimental results of the load weight. The resonance frequency is measured by the rotation experiments. The rotor achieves stable levitation even in the resonance state. In the hybrid system, effect of the pinning force becomes smaller than that of the lateral force generated by the repulsive force between the two permanent magnets at the smaller air gap. Thus influence of the lateral vibration and the gradient angle in the resonance state becomes larger at a smaller air gap. The equivalent magnetic spring coefficient becomes also small, and the resonance frequency becomes small in the hybrid bearing system.

Characterization of human breast disease using phosphorus magnetic resonance spectroscopy and proton magnetic resonance imaging

International Nuclear Information System (INIS)

Merchant, T.E.

1992-01-01

This thesis provides the fundamental characterization and differentiation of breast tissues using in vivo and ex vivo MR techniques in the hope that these techniques and experimental findings will be used on a larger scale and in a predictive manner in order to improve the specificity of diagnosis and treatment of breast cancer. In this dissertation, clinical studies were performed using proton magnetic resonance imaging and phosphorus magnetic resonance spectro-scopy ( 31 P MRS) to characterize and differentiate malignant breast tumors, benign breast tumors and normal breast tissues in vivo. These studies were carried out following the methodical characterization of chemical extracts of malignant breast tumor, benign breast tumor and normal breast parenchymal surgical tissue specimens using high resolution 31 P MRS. Alterations in breast tissue metabolism, as a result of pathological processes, were postulated to be responsible for measurable differences between malignant breast tumors, benign breast tumors and normal breast tissues using magnetic resonance techniques. (author). 365 refs.; 37 figs.; 25 tabs

Cardiovascular magnetic resonance in congenital heart disease

International Nuclear Information System (INIS)

Cazacu, A.; Ciubotaru, A.

2010-01-01

The increasing prevalence of congenital heart disease can be attributed to major improvements in diagnosis and treatment. Cardiovascular magnetic resonance imaging plays an important role in the clinical management strategy of patients with congenital heart disease. The development of new cardiovascular magnetic resonance (CMR) techniques allows comprehensive assessment of complex cardiac anatomy and function and provides information about the long-term residual post-operative lesions and complications of surgery. It overcomes many of the limitations of echocardiography and cardiac catheterization. This review evaluates the role of cardiovascular magnetic resonance imaging modality in the management of subject with congenital heart disease (CHD). (authors)

Magnetic resonance imaging of the central nervous system

International Nuclear Information System (INIS)

Brant-Zawadzki, M.; Norman, D.

1987-01-01

This book presents the papers on technological advancement and diagnostic uses g magnetic resonance imaging. A comparative evaluation with computerized tomography is presented. Topics covered are imaging principles g magnetic resonance;instrumentation of magnetic resonance (MR);pathophysiology;quality and limitations g images;NMR imaging of brain and spinal cord;MR spectroscopy and its applications;neuroanatomy;Congenital malformations of brain and MR imaging;planning g MR imaging of spine and head and neck imaging

Nuclear magnetic resonance spectroscopy and imaging

International Nuclear Information System (INIS)

Jiang Weiping; Wang Qi; Zhou Xin

2013-01-01

This paper briefly introduces the basic principle of nuclear magnetic resonance (NMR). Protein's structures and functions and dynamics studied by liquid NMR are elaborated; methods for enhancing the resolution of solid state NMR and its applications are discussed; the principle of magnetic resonance imaging (MRI) is interpreted, and applications in different aspects are reviewed. Finally, the progress of NMR is commented. (authors)

Diagnostic apparatus employing nuclear magnetic resonance

International Nuclear Information System (INIS)

Hoshino, K.; Yamada, N.; Yoshitome, E.; Matsuura, H.

1987-01-01

An NMR diagnostic apparatus is described comprising means for applying a primary magnetic field to a subject; means for applying RF pulses to the subject to give nuclear magnetic resonance to the nuclei of atoms in the subject; means for applying gradient magnetic fields to project an NMR signal of the nuclei at least in one direction; means for observing the NMR signal projected by the gradient magnetic fields applying means; and arithmetic means for constructing a distribution of information on resonance energy as an image from an output signal from the observing means; wherein the gradient magnetic fields applying means comprises means for applying the gradient magnetic fields at a predetermined time and for not applying the gradient magnetic fields at another predetermined time, during the time period of one view; and wherein the gradient magnetic fields applying means further comprises means for measuring the NMR signal during the predetermined time when the gradient magnetic fields are applied, and means for measuring the intensity of the primary magnetic field during the other predetermined time when no gradient magnetic fields are applied

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... Sometimes ultrasound is substituted for CT as a method of imaging in these procedures in children. A ... 450 pounds—for the moving table. Other imaging methods such as ultrasound or magnetic resonance (MR) imaging ...

Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

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Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

2008-11-15

To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes; Reed, Umbertina Conti; Rosemberg, Sergio

2008-01-01

To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

Evaluation of nuclear magnetic resonance spectroscopy variability

Energy Technology Data Exchange (ETDEWEB)

Barreto, Felipe Rodrigues; Salmon, Carlos Ernesto Garrido, E-mail: garrido@ffclrp.usp.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filisofia, Ciencias e Letras; Otaduy, Maria Concepcion Garcia [Universidade de Sao Paulo (FAMUS/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Departamento de Radiologia

2014-11-01

Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

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

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Lumbar Spine What's in this article? ...

Nuclear magnetic resonance and earth magnetic field

International Nuclear Information System (INIS)

Anon.

1998-01-01

Nuclear magnetic resonance concerns nuclei whose spin is different from 0. These nuclei exposed to a magnetic field is comparable to a peg top spinning around its axis while being moved by a precession movement called Larmor precession. This article presents an experiment whose aim is to reveal nuclear magnetism of nuclei by observing Larmor precession phenomena due to the earth magnetic field. The earth magnetic field being too weak, it is necessary to increase the magnetization of the sample during a polarization phase. First the sample is submitted to a magnetic field B perpendicular to the earth magnetic field B 0 , then B is cut off and the nuclei move back to their equilibrium position by executing a precession movement due to B 0 field. (A.C.)

Computed tomography and magnetic resonance imaging findings of solitary fibrous tumors in the pelvis: Correlation with histopathological findings

International Nuclear Information System (INIS)

Zhang Weidong; Chen Jianyu; Cao Yun; Liu Qingyu; Luo Rongguang

2011-01-01

Objective: We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of pelvic solitary fibrous tumors (SFTs) and to improve the diagnostic efficacy for such tumors. Methods: Six cases of pelvic SFTs confirmed by histopathology were analyzed retrospectively. Of the 6 patients, 4 had undergone CT scanning, and 2 had undergone magnetic resonance imaging. All the patients had undergone unenhanced and contrast-enhanced examinations, and 2 had also undergone dynamic CT enhancement examination. Image characteristics such as shape, size, number, edge, attenuation or intensity for each lesion before and after contrast enhancement were analyzed and compared with the pathomorphology of the tumors. Results: All the 6 cases showed oval or rounded and well-defined masses. Unenhanced CT images showed heterogeneous masses with patchy, necrotic foci in 3 cases and homogeneous mass in 1 case. None of the tumors showed calcification. Contrast-enhanced CT images showed marked, heterogeneous enhancement in the first and second cases. Dynamic enhancement scan demonstrated mild homogeneous enhancement in the third case and mild prolonged, delayed enhancement and washout in the fourth case. T1-weighted MR images showed heterogeneous mild hypointense lesion with linear hyperintensity in 1 case, and homogeneous isointensity in the other. T2-weighted images showed heterogeneous mixed intensity in 1 case and mostly hyperintensive lesion with hypointense foci in another case. A case showed marked heterogeneous enhancement and another showed marked homogeneous enhancement on contrast-enhanced T1-weighted images. Conclusion: Radiological findings of pelvic SFTs are variable and nonspecific. However, a well-defined, ovoid or rounded mass with hypointense on MR T2-weighted images and variable enhancement on CT and MR images may suggest the diagnosis of SFTs. Pelvic SFTs should be included in the differential diagnosis of regional tumors.

Resonance double magnetic bremsstrahlung in a strong magnetic field

International Nuclear Information System (INIS)

Fomin, P.I.; Kholodov, R.I.

2003-01-01

The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory)

Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

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Guimaraes, Marcos Duarte; TyngI, Chiang Cheng; Bitencourt, Almir Galvao Vieira; Gross, Jefferson Luiz; Zurstrassen, Charles Edouard, E-mail: marcosduarte500@gmail.com [AC Camargo Cancer Center, Sao Paulo, SP (Brazil); Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Dept. de Radiologia; Benveniste, Marcelo Felipe Kuperman; Odisio, Bruno Calazans [University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), Petropolis, RJ (Brazil)

2014-11-15

Objectives: to evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. Methods: eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. Results: in all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6–1.1]610{sup -3} mm{sup 2}/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymoma s. Conclusion: functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques. (author)

Study of the usefulness of magnetic resonance imaging on neurological disorders

Energy Technology Data Exchange (ETDEWEB)

Hokezu, Youichi (Kagoshima Univ. (Japan). Faculty of Medicine)

1992-05-01

One hundred and ten patients with several neurological disorders including cerebrovascular diseases (CVD), degenerative diseases, demyelinating diseases, infections of the nervous systems, neurometabolic disorders, myopathies, diseases of the spine or spinal cord and myelopathy were studied by employing magnetic resonance imaging (MRI). Superconductive magnetic systems of 0.5 T, 1.0 T or 1.5 T were used for this study. MRI could show the lesions clearly in many neurological disorders such as CVD, demyelinating diseases, infections of the nervous systems, neurometabolic disorders, myopathies and myeloythy. However, MRI could not necessarily show the lesions cleary in neurodegenerative disease and bone or calcified lesions such as ossification of posterior longitudinal ligament. MRI is better than CT in spatial and tissue resolution. MRI study is expected to be the more beneficial procedure in neurological disorders, if a much shorter scanning time can be achieved. (author).

Study of the usefulness of magnetic resonance imaging on neurological disorders

International Nuclear Information System (INIS)

Hokezu, Youichi

1992-01-01

One hundred and ten patients with several neurological disorders including cerebrovascular diseases (CVD), degenerative diseases, demyelinating diseases, infections of the nervous systems, neurometabolic disorders, myopathies, diseases of the spine or spinal cord and myelopathy were studied by employing magnetic resonance imaging (MRI). Superconductive magnetic systems of 0.5 T, 1.0 T or 1.5 T were used for this study. MRI could show the lesions clearly in many neurological disorders such as CVD, demyelinating diseases, infections of the nervous systems, neurometabolic disorders, myopathies and myeloythy. However, MRI could not necessarily show the lesions cleary in neurodegenerative disease and bone or calcified lesions such as ossification of posterior longitudinal ligament. MRI is better than CT in spatial and tissue resolution. MRI study is expected to be the more beneficial procedure in neurological disorders, if a much shorter scanning time can be achieved. (author)

Evaluation of urogenital fistulas by magnetic resonance urography

International Nuclear Information System (INIS)

Mamere, Augusto Elias; Coelho, Rafael Darahem Souza; Cecin, Alexandre Oliveira; Feltrin, Leonir Terezinha; Lucchesi, Fabiano Rubiao; Seabra, Daniel

2008-01-01

Objective: Vesicovaginal and ureterovaginal fistulas are unusual complications secondary to pelvic surgery or pelvic diseases. The therapeutic success in these cases depends on an appropriate preoperative evaluation for diagnosis and visualization of the fistulous tract. The present study is aimed at demonstrating the potential of magnetic resonance urography for the diagnosis of vesicovaginal and ureterovaginal fistulas as well as for defining the fistulous tracts. Materials And Methods: Seven female patients clinically diagnosed with vesicovaginal or ureterovaginal fistulas had their medical records, radiological and magnetic resonance images retrospectively reviewed. Magnetic resonance urography included 3D-HASTE sequences with fat saturation. Results: Six patients presented vesicovaginal fistulas and, in one patient, a right-sided ureterovaginal fistula was diagnosed. Magnetic resonance urography allowed the demonstration of the fistulous tract in six (85.7%) of the seven patients evaluated in the present study, without the need of bladder catheterization or contrast injection. Conclusion: This study demonstrates both the potential and applicability of magnetic resonance urography in the evaluation of these types of fistulas. (author)

Object-oriented magnetic resonance classes and objects, calculations and computations

CERN Document Server

Mehring, Michael

2001-01-01

This book presents, for the first time, a unified treatment of the quantum mechanisms of magnetic resonance, including both nuclear magnetic resonance (NMR) and electron spin resonance (ESR). Magnetic resonance is perhaps the most advanced type of spectroscopy and it is applied in biology, chemistry, physics, material science, and medicine. If applied in conjunction with spectroscopy, the imaging version of magnetic resonance has no counterpart in any type of experimental technique. The authors present explanations and applications from fundamental to advanced levels. Additionally, the

Magnetic resonance enterography in pediatric celiac disease.

Science.gov (United States)

Koc, Gonca; Doganay, Selim; Sevinc, Eylem; Deniz, Kemal; Chavhan, Govind; Gorkem, Sureyya B; Karacabey, Neslihan; Dogan, Mehmet S; Coskun, Abdulhakim; Aslan, Duran

To assess if magnetic resonance enterography is capable of showing evidence/extent of disease in pediatric patients with biopsy-proven celiac disease by comparing with a control group, and to correlate the magnetic resonance enterography findings with anti-endomysial antibody level, which is an indicator of gluten-free dietary compliance. Thirty-one pediatric patients (mean age 11.7±3.1 years) with biopsy-proven celiac disease and 40 pediatric patients as a control group were recruited in the study. The magnetic resonance enterography images of both patients with celiac disease and those of the control group were evaluated by two pediatric radiologists in a blinded manner for the mucosal pattern, presence of wall thickening, luminal distention of the small bowel, and extra-intestinal findings. Patient charts were reviewed to note clinical features and laboratory findings. The histopathologic review of the duodenal biopsies was re-conducted. The mean duration of the disease was 5.6±1.8 years (range: 3-7.2 years). In 24 (77%) of the patients, anti-endomysial antibody levels were elevated (mean 119.2±66.6RU/mL). Magnetic resonance enterography revealed normal fold pattern in all the patients. Ten (32%) patients had enlarged mesenteric lymph nodes. Although a majority of the patients had elevated anti-endomysial antibody levels indicating poor dietary compliance, magnetic resonance enterography did not show any mucosal abnormality associated with the inability of magnetic resonance enterography to detect mild/early changes of celiac disease in children. Therefore, it may not be useful for the follow-up of pediatric celiac disease. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Theoretical study of ferromagnetic resonance in exchange - coupled magnetic / nonmagnetic / magnetic multilayer structure

International Nuclear Information System (INIS)

Oezdogan, K.; Oezdemir, M.; Yalcin, O.; Aktas, B.

2002-01-01

The dispersion relation on ferromagnetic films was calculation by using torque equation of motion with a damping term. The total energy including zeeman, demagnetizing and anisotropy energy terms was used to get ferromagnetic resonance frequency for both uniform and higher order spin wave modes. In antiferromagnetic films, the torque equation of motion for each sub-lattice were written to derive an expression for the dispersion relation. The magnetic trilayer system under investigation consist of two ferromagnetic layers separated by a nonmagnetic layer. The dispersion relation of magnetic/nonmagnetic/magnetic three layers is calculated by using Landau-Lifshitz dynamic equation of motion for the magnetization with interlayer exchange energy. As for the exchange-coupled resonance of ferromagnetic resonance (FMR), the theoretical study has been calculated for both symmetrical and asymmetrical structures. In this systems, the exchange-coupling parameter A 12 between neighboring layers was used to get resonance fields as a function of the angle between the magnetization vectors of each magnetic layers

Magnetic elliptical polarization of Schumann resonances

International Nuclear Information System (INIS)

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. 16 references

Functional magnetic resonance imaging by visual stimulation

International Nuclear Information System (INIS)

Nishimura, Yukiko; Negoro, Kiyoshi; Morimatsu, Mitsunori; Hashida, Masahiro

1996-01-01

We evaluated functional magnetic resonance images obtained in 8 healthy subjects in response to visual stimulation using a conventional clinical magnetic resonance imaging system with multi-slice spin-echo echo planar imaging. Activation in the visual cortex was clearly demonstrated by the multi-slice experiment with a task-related change in signal intensity. In addition to the primary visual cortex, other areas were also activated by a complicated visual task. Multi-slice spin-echo echo planar imaging offers high temporal resolution and allows the three-dimensional analysis of brain function. Functional magnetic resonance imaging provides a useful noninvasive method of mapping brain function. (author)

Musculoskeletal applications of magnetic resonance imaging: Council on Scientific Affairs

International Nuclear Information System (INIS)

Harms, S.E.; Fisher, C.F.; Fulmer, J.M.

1989-01-01

Magnetic resonance imaging provides superior contrast, resolution, and multiplanar imaging capability, allowing excellent definition of soft-tissue and bone marrow abnormalities. For these reasons, magnetic resonance imaging has become a major diagnostic imaging method for the evaluation of many musculoskeletal disorders. The applications of magnetic resonance imaging for musculoskeletal diagnosis are summarized and examples of common clinical situations are given. General guidelines are suggested for the musculoskeletal applications of magnetic resonance imaging

Magnetic resonance imaging and angiography of the brain in embolic left atrial myxoma

International Nuclear Information System (INIS)

Marazuela, M.; Yebra, M.; Diego, J.; Durantez, A.; Garcia-Merino, A.; Brasa, J.M.

1989-01-01

A case of left atrial myxoma presenting exclusively with neurological symptoms, studies with magnetic resonance imaging (MRI) combined with cerebral angiography and computed tomography (CT) is reported. Typical angiographic findings suggested the diagnosis of myxoma. MRI showed multiple ischemic lesions disseminated throughout the entire brain, some of which had been clinically asymptomatic. Because of its sensitivity in identifying small cerebral infarcts, MRI should prove in the future to be a first-choice technique in the evaluation of the presence of an extent of cerebral involvement in embolic left atrial myxoma. (orig.)

Magnetic resonance of native defects of spin-Peierls magnetics CuGeO3

International Nuclear Information System (INIS)

Smirnov, A.I.; Glazkov, V.N.; Leonyuk, L.I.; Vetkin, A.G.; Eremina, R.M.

1998-01-01

Magnetic resonance within 9-75 GHz frequency range and 1.2-25 K temperature range was studied in pure monocrystalline spin-Peierls CuGwO 3 . Splitting of the magnetic resonance line is observed within temperature range below 5 K. Analysis of magnetic resonance spectra at various directions of magnetic field and under various temperatures enables to set off EPR-signals of spin-Peierls phase defects with S=1/2 and defects with S=1 from these components; g-factor corresponding to these EPR signals is similar one and close to values typical for Cu 2+ ion [ru

Green’s function theory of ferromagnetic resonance in magnetic superlattices with damping

International Nuclear Information System (INIS)

Qiu, R.K.; Guo, F.F.; Zhang, Z.D.

2016-01-01

We explore a quantum Green’s-function method to study the resonance absorption of magnetic materials. The relationship between the resonance magnon (spin wave) density and the resonance frequency of a superlattice consisting of two magnetic layers with damping and antiferromagnetic interlayer exchange coupling is studied. The effects of temperature, interlayer coupling, anisotropy, external magnetic field and damping on the the resonance frequency and resonance magnon density are investigated. The resonance excitation probability for a magnon is proportional to the resonance magnon density. In the classic methods, the imaginary part of magnetic permeability represents the resonance absorption in magnetic materials. In the quantum approach, the resonance magnon density can be used to estimate the strength of the resonance absorption. In the present work, a quantum approach is developed to study resonance absorption of magnetic materials and the results show the method to obtain a magnetic multilayered materials with both high resonance frequency and high resonance absorption.

Green’s function theory of ferromagnetic resonance in magnetic superlattices with damping

Energy Technology Data Exchange (ETDEWEB)

Qiu, R.K., E-mail: rkqiu@163.com [Shenyang University of Technology, Shenyang 110870 (China); Guo, F.F. [Shenyang University of Technology, Shenyang 110870 (China); Zhang, Z.D. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2016-02-01

We explore a quantum Green’s-function method to study the resonance absorption of magnetic materials. The relationship between the resonance magnon (spin wave) density and the resonance frequency of a superlattice consisting of two magnetic layers with damping and antiferromagnetic interlayer exchange coupling is studied. The effects of temperature, interlayer coupling, anisotropy, external magnetic field and damping on the the resonance frequency and resonance magnon density are investigated. The resonance excitation probability for a magnon is proportional to the resonance magnon density. In the classic methods, the imaginary part of magnetic permeability represents the resonance absorption in magnetic materials. In the quantum approach, the resonance magnon density can be used to estimate the strength of the resonance absorption. In the present work, a quantum approach is developed to study resonance absorption of magnetic materials and the results show the method to obtain a magnetic multilayered materials with both high resonance frequency and high resonance absorption.

Least Squares Magnetic-Field Optimization for Portable Nuclear Magnetic Resonance Magnet Design

International Nuclear Information System (INIS)

Paulsen, Jeffrey L; Franck, John; Demas, Vasiliki; Bouchard, Louis-S.

2008-01-01

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 in a 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'

Clinical magnetic resonance: imaging and spectroscopy

International Nuclear Information System (INIS)

Andrew, E.R.; Bydder, Graeme; Griffiths, John; Iles, Richard; Styles, Peter

1990-01-01

This book begins with a readable, comprehensive but non-mathematical introduction to the basic underlying principles of magnetic resonance. Further chapters include information on the theory and principles of MRI and MRS, the interpretation of MR images, the clinical applications and scope of MRI and MRS, practical aspects of spectroscopy and magnetic resonance, and also the practical problems associated with the siting, safety and operation of large MRI and MRS equipment. (author)

Synthese und Charakterisierung amphiphiler Porphyrinoide als Kontrastmittel für das Magnetic Resonance Imaging (MRI)

OpenAIRE

Neumann, Yvonne

2011-01-01

Magnetic resonance imaging (MRI) is a diagnostic tool, which is commonly used in visualization of internal procedures in the living tissue. Used in visualizing procedures, MRI shows an increased contrast-enhancing effect in soft tissue in contrast to other techniques like computer tomography (CT). MRI does not need any ionizing radiation and provides three dimensional tomographic shots. One of the first commonly used porphyrin-based contrast agents was Gadophrin-2, which has a high affinity t...

Contribution of magnetic resonance imaging to the diagnosis of multiple sclerosis

International Nuclear Information System (INIS)

Seidl, Z.; Obenberger, J.; Vitak, T.

1996-01-01

The potential of magnetic resonance imaging in the diagnosis of multiple sclerosis (MS) was confirmed on 52 patients. In 25 patients, MS was diagnosed as highly probable, in additional 8 patients this diagnosis was suspected. MR imaging supported the diagnosis in 21 (95%) patients where this disease had been diagnosed as highly probable, and in 3 (38%) suspect patients. Lesions were found most frequently paraventricularly in the white matter of the brain, but also in the deep structures of the white matter of the temporal lobe and below the tentorium (in the cerebellum, pons and mesencephalon). No lesions were found in the optic nerve despite the frequent diagnosis of retrobulbar neuritis. Computerized tomography (CT) was performed in 14 patients; this technique only supported the diagnosis of MS in 3 patients, in all of whom this diagnosis had also been suggested by MR imaging. It is concluded that MR imaging can fully supersede CT as a tool for diagnosing multiple sclerosis. 3 figs., 10 refs

Magnetic resonance in prenatal diagnosis of thoracic anomalies

International Nuclear Information System (INIS)

Pietrani, M.; Elias, D.; Wojakowski, A.; Fataljaef, V.; Carcano, M.; Otano, L.

2007-01-01

The objective of this article is to communicate the experience in the evaluation of fetal anomalies thoracic by means of magnetic resonance. Between January, 2001 - March, 2007 16 fetus were evaluated by means of magnetic resonance with echographic diagnosis of thoracic anomalies. An equipment of 1.5 TESLA was used. The thoracic anatomy was valued in general. At the presence of discovering pulmonary mass, their size, volume and intensity of sign were determined. The echographic and magnetic resonance findings were checked against the perinatal results [es

Role of chelates in magnetic resonance imaging studies

Directory of Open Access Journals (Sweden)

Tripathi Laxmi

2009-01-01

Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

Contrast enhanced magnetic resonance imaging of the brain using gadolinium-DTPA

International Nuclear Information System (INIS)

Valk, J.; Slegte, R.G.M. de; Crezee, F.C.; Hazenberg, G.J.; Thjaha, S.I.; Nauta, J.J.P.; Vrije Univ., Amsterdam; Vrije Univ., Amsterdam; Vrije Univ., Amsterdam

1987-01-01

This report concerns a clinical trial with gadolinium-DTPA (Gd-DTPA) as an intravenous contrast medium for magnetic resonance imaging (MRI) in patients with disorders of the central nervous system. Fifty patients, 30 females and 20 males, were examined without and with Gd-GTPA. The contrast medium was well tolerated by all patients. The results of MRI scanning without and with Gd-DTPA and those obtained with computed tomography (CT) using intravenous contrast enhancement were compared. This investigation comprised mainly patients with intracranial tumors, multiple sclerosis, and nasopharyngeal tumors. The results may be summarized as follows: 1) MRI with Gd-DTPA (MRI+) gave better results than MRI without Gd as regards delineation of the lesion, blood vessels and edema in cerebral tumors, pituitary adenomas and acute forms of multiple sclerosis (MS). MRI+ was better than CT in 32 of the 50 cases examined; with intracerebral tumors it was better in 15 out of 18 cases. 3) MRI+ was always better than CT in patients with MS. In 3 out of 7 cases MRI demonstrated the acute MS lesions. 4) MRI+ seemed to have advantages also in nasopharyngeal tumors as ascertained from this limited experience. (orig.)

Research advances in computed tomography and magnetic resonance imaging findings of cirrhotic portal hypertension

Directory of Open Access Journals (Sweden)

YAN Fuhua

2016-06-01

Full Text Available Portal hypertension is the most common complication of liver cirrhosis. Noninvasive radiological examinations have important values in evaluating liver parenchyma, collateral circulation, and esophagogastric variceal bleeding in liver cirrhosis. Computed tomography (CT and magnetic resonance imaging (MRI can reflect the changes in liver morphology, the density and signals of liver parenchyma, and hemodynamics and have important values in disease diagnosis and prognostic evaluation. CT and functional MRI, such as perfusion-weighted imaging, MR elastography, and MR diffusion-weighted imaging, can provide quantitative information and can be applied in the diagnosis of hepatic fibrosis and early-stage liver cirrhosis in clinical practice. CT angiography and MR angiography, especially unenhanced MR angiography, can show the condition of the branches of portal vein, which helps to evaluate the risk of esophagogastric variceal bleeding and detect the markers for early warning. A combination of CT and MRI and evaluation of their potential in clinical application can give full play to the role of radiological examinations in the diagnosis, evaluation, and prognostic analysis of cirrhotic portal hypertension.

Recommendations concerning magnetic resonance spectroscopy

International Nuclear Information System (INIS)

1986-01-01

In medicine the technique of nuclear magnetic resonance (NMR) is applied in the form of in vivo nuclear magnetic resonance spectroscopy (MRS). In vivo MRS can be carried out non-invasively. The committee of the Dutch Health Council briefly discusses the qualities and potentialities of the nuclei that will probably be used in future clinical spectroscopy: 31 P, 13 C, 1 H (and possibly 19 F and 23 Na). The committee discusses several possibilities of combining imaging and spectroscopy. The imaging of nuclei other than protons is also possible with MRS. Potential applications are considered in oncology, cardiology, neurology and hepatology. (Auth.)

Computed tomography and magnetic resonance imaging in vascular surgical emergencies

International Nuclear Information System (INIS)

Vogelzang, R.L.; Fisher, M.R.

1987-01-01

Computed tomography (CT) scanning is now universally accepted as an extremely useful tool in the investigation of disease throughout the body. CT has revolutionized the practice of medicine in virtually every specialty. In vascular surgery the routine use of CT in a variety of problems has changed the way diagnoses are made. It allows prompt recognition of conditions that were difficult if not impossible to diagnose using older techniques. Nowhere is this concept better epitomized than in the realm of vascular surgical emergencies. In these cases, life or limb threatening conditions such as hemorrhage, prosthetic graft infection, or vascular occlusion exist as the result of aneurysm, trauma, dissection, tumor, or previous arterial surgery. Prompt and appropriate diagnosis of the immediate problem and its cause is afforded by the use of contrast enhanced CT. This frequently obviates the need for angiography and eliminates less accurate tests such as plain films, barium studies, nuclear medicine scans, and/or ultrasound. In the past several years magnetic resonance imaging (MRI) of the body has become a practical reality. The technique offers promise in the imaging of many disease processes. In the neural axis it has become a preferred modality due to inherently higher contrast resolution and freedom from artifacts. Progress in body imaging has been slower due to problems with motion artifact but early results in cardiovascular imaging demonstrate that MRI offers theoretical advantages over CT that may make it the imaging test of choice in vascular disease. This paper identifies those vascular surgical emergencies in which CT and MRI are most useful and clarifies and illustrates the diagnostic features of the various conditions encountered

Prebiopsy magnetic resonance spectroscopy and imaging in the diagnosis of prostate cancer

International Nuclear Information System (INIS)

Kumar, V.; Jagannathan, N.R.; Thulkar, S.; Kumar, R.

2012-01-01

Existing screening investigations for the diagnosis of early prostate cancer lack specificity, resulting in a high negative biopsy rate. There is increasing interest in the use of various magnetic resonance methods for improving the yield of transrectal ultrasound-guided biopsies of the prostate in men suspected to have prostate cancer. We review the existing status of such investigations. A literature search was carried out using the Pubmed database to identify articles related to magnetic resonance methods for diagnosing prostate cancer. References from these articles were also extracted and reviewed. Recent studies have focused on prebiopsy magnetic resonance investigations using conventional magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging, diffusion weighted magnetic resonance imaging, magnetization transfer imaging and magnetic resonance spectroscopy of the prostate. This marks a shift from the earlier strategy of carrying out postbiopsy magnetic resonance investigations. Prebiopsy magnetic resonance investigations has been useful in identifying patients who are more likely to have a biopsy positive for malignancy. Prebiopsy magnetic resonance investigations has a potential role in increasing specificity of screening for early prostate cancer. It has a role in the targeting of biopsy sites, avoiding unnecessary biopsies and predicting the outcome of biopsies. (author)

Magnetic Resonance Imaging of Surgical Implants Made from Weak Magnetic Materials

Science.gov (United States)

Gogola, D.; Krafčík, A.; Štrbák, O.; Frollo, I.

2013-08-01

Materials with high magnetic susceptibility cause local inhomogeneities in the main field of the magnetic resonance (MR) tomograph. These inhomogeneities lead to loss of phase coherence, and thus to a rapid loss of signal in the image. In our research we investigated inhomogeneous field of magnetic implants such as magnetic fibers, designed for inner suture during surgery. The magnetic field inhomogeneities were studied at low magnetic planar phantom, which was made from four thin strips of magnetic tape, arranged grid-wise. We optimized the properties of imaging sequences with the aim to find the best setup for magnetic fiber visualization. These fibers can be potentially exploited in surgery for internal stitches. Stitches can be visualized by the magnetic resonance imaging (MRI) method after surgery. This study shows that the imaging of magnetic implants is possible by using the low field MRI systems, without the use of complicated post processing techniques (e.g., IDEAL).

Magnetic resonance instrumentation

International Nuclear Information System (INIS)

Bell, R.A.

1987-01-01

Magnetic resonance (MR), while opening new vistas to diagnostic medicine, utilizes equipment that is unfamiliar to most clinicians. Beyond learning to cope with new terms, such as spin-echo, T1, T2, and spin density, health care professionals are faced with the inclusion of magnetic and radiofrequency effects in their facilities produced by a complex array of devices. It is the purpose of this chapter to outline the components of an MR imaging system, to discuss their functions, and to note the variations in equipment commercially available

Parenchymal abnormalities in cerebral venous thrombosis: findings of magnetic resonance imaging and magnetic resonance angiography

International Nuclear Information System (INIS)

Ferreira, Clecia Santos; Pellini, Marcos; Boasquevisque, Edson; Souza, Luis Alberto M. de

2006-01-01

Objective: to determine the frequency and localization of parenchymal abnormalities in cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography as well as their correlation with the territory and affected venous drainage. Materials and methods: retrospective analysis (1996 to 2004) of 21 patients (3 male and 18 female) age range between 3 and 82 years (mean 40 years, median 36 years) with clinical and radiological diagnosis of cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography in 2D PC, 3D PC and contrast-enhanced 3D TOF sequences. The statistical analysis was performed with the qui-square test. Four patients had follow-up exams and three patients underwent digital subtraction angiography. Results: main predisposing factors were: infection, use of oral contraceptives, hormone replacement therapy and collagenosis. Predominant symptoms included: focal deficit, headache, alteration of consciousness level and seizures. Most frequent parenchymal manifestations were: cortical/subcortical edema or infarct, venous congestion and collateral circulation, meningeal enhancement and thalamic and basal ganglia edema or infarct. Occlusion occurred mainly in superior sagittal, left transverse, left sigmoid and straight sinuses. Cavernous sinus and cortical veins thrombosis are uncommon events. Conclusion: cerebral venous thrombosis is an uncommon cause of stroke, with favorable prognosis because of its reversibility. Diagnosis is highly dependent on the radiologist capacity to recognize the presentations of this disease, principally in cases where the diagnosis is suggested by parenchymal abnormalities rather than necessarily by visualization of the thrombus itself. An accurate and rapid diagnosis allows an immediate treatment, reducing the morbidity and mortality rates. (author)

Nuclear magnetic resonance spectroscopy in organic chemistry. 2. ed.

International Nuclear Information System (INIS)

Zschunke, A.

1977-01-01

The fundamentals of nuclear magnetic resonance spectroscopy are discussed only briefly. The emphasis is laid on developing reader's ability to evaluate resonance spectra. The following topics are covered: principles of nuclear magnetic resonance spectroscopy; chemical shift and indirect nuclear spin coupling constants and their relation to the molecular structure; analysis of spectra; and uses for structural analysis and solution of kinetic problems, mainly with regard to organic compounds. Of interest to chemists and graduate students who want to make themselves acquainted with nuclear magnetic resonance spectroscopy

Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session

International Nuclear Information System (INIS)

Boraschi, P.; Donati, F.; Gigoni, R.; Salemi, S.; Urbani, L.; Filipponi, F.; Falaschi, F.; Bartolozzi, C.

2008-01-01

To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T 1 w and T 2 w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T 2 w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T 1 w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation. (author)

Magnetic resonance imaging - first human images in Australia

International Nuclear Information System (INIS)

Baddeley, H.; Doddrell, D.M.; Brooks, W.M.; Field, J.; Irving, M.; Williams, J.E.

1986-01-01

The use of magnetic resonance imaging, in the demonstration of internal human anatomy and in the diagnosis of disease, has the major advantages that the technique is non-invasive, does not require the use of ionizing radiation and that it can demonstrate neurological and cardiovascular lesions that cannot be diagnosed easily by other imaging methods. The first magnetic resonance images of humans were obtained in Australia in October 1985 on the research instrument of the Queensland Medical Magnetic Resonance Research Centre, which is based at the Mater Hospital in Brisbane

Magnetic resonance imaging of radiation optic neuropathy

International Nuclear Information System (INIS)

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

1990-01-01

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

Giant magnetic modulation of a planar, hybrid metamolecule resonance

International Nuclear Information System (INIS)

Gregory, Simon A; Stenning, Gavin B G; Bowden, Graham J; De Groot, Peter A J; Zheludev, Nikolay I

2014-01-01

Coupling magnetic elements to metamaterial structures creates hybrid metamolecules with new opportunities. Here we report on the magnetic control of a metamolecule resonance, by utilizing the interaction between a single split ring resonator (SRR) and a magnetic thin film of permalloy. To suppress eddy current shielding, the permalloy films are patterned into arrays of 30–500 μm diameter discs. Strong hybridized resonances were observed at the anticrossing between the split ring resonance and the ferromagnetic resonance (FMR) of the permalloy. In particular, it is possible to achieve 40 dB modulation of the electric (symmetric) mode of the SRR on sweeping the applied magnetic field through the SRR/FMR anticrossing. The results open the way to the design of planar metamaterials, with potential applications in nonlinear metamaterials, tunable metamaterials and spintronics. (papers)

Magnetic resonance imaging of muscle tears

International Nuclear Information System (INIS)

De Smet, A.A.; Fisher, D.R.; Heiner, J.P.; Keene, J.S.

1990-01-01

Magnetic resonance scans were obtained on 17 patients with acute, subacute, or chronic muscle tears. These patients presented with complaints of persistent pain or a palpable mass. Magnetic resonance findings were characterized according to alterations in muscle shape and the presence of abnormal high signal within the injured muscle. These areas of high signal were noted on both T1-weighted and T2-weighted scans and were presumed to represent areas of intramuscular hemorrhage. (orig.)

Magnetic resonance of rubidium atoms passing through a multi-layered transmission magnetic grating

International Nuclear Information System (INIS)

Nagata, Y; Kurokawa, S; Hatakeyama, A

2017-01-01

We measured the magnetic resonance of rubidium atoms passing through periodic magnetic fields generated by two types of multi-layered transmission magnetic grating. One of the gratings reported here was assembled by stacking four layers of magnetic films so that the direction of magnetization alternated at each level. The other grating was assembled so that the magnetization at each level was aligned. For both types of grating, the experimental results were in good agreement with our calculations. We studied the feasibility of extending the frequency band of the grating and narrowing its resonance linewidth by performing calculations. For magnetic resonance precision spectroscopy, we conclude that the multi-layered transmission magnetic grating can generate periodic fields with narrower linewidths at higher frequencies when a larger number of layers are assembled at a shorter period length. Moreover, the frequency band of this type of grating can potentially achieve frequencies of up to hundreds of PHz. (paper)

Magnetic resonance imaging of breast implants.

Science.gov (United States)

Shah, Mala; Tanna, Neil; Margolies, Laurie

2014-12-01

Silicone breast implants have significantly evolved since their introduction half a century ago, yet implant rupture remains a common and expected complication, especially in patients with earlier-generation implants. Magnetic resonance imaging is the primary modality for assessing the integrity of silicone implants and has excellent sensitivity and specificity, and the Food and Drug Administration currently recommends periodic magnetic resonance imaging screening for silent silicone breast implant rupture. Familiarity with the types of silicone implants and potential complications is essential for the radiologist. Signs of intracapsular rupture include the noose, droplet, subcapsular line, and linguine signs. Signs of extracapsular rupture include herniation of silicone with a capsular defect and extruded silicone material. Specific sequences including water and silicone suppression are essential for distinguishing rupture from other pathologies and artifacts. Magnetic resonance imaging provides valuable information about the integrity of silicone implants and associated complications.

Magnetic Resonance (MR) Defecography

Science.gov (United States)

... to a CD or uploaded to a digital cloud server. Magnetic resonance (MR) defecography is a special ... with you. top of page What are the benefits vs. risks? Benefits MR defecography helps assess pelvic ...

Magnetic resonance imaging in diffuse brain injury

International Nuclear Information System (INIS)

Yokota, Hiroyuki; Yasuda, Kazuhiro; Mashiko, Kunihiro; Henmi, Hiroshi; Otsuka, Toshibumi; Kobayashi, Shiro; Nakazawa, Shozo

1992-01-01

Forty cases diagnosed as diffuse brain injury (DBI) were studied by magnetic resonance imaging (MRI) performed within 3 days after injury. These cases were divided into two groups, which were the concussion group and diffuse axonal injury (DAI) group established by Gennarelli. There were no findings on computerized tomography (CT) in the concussion group except for two cases which had a brain edema or subarachnoid hemorrhage. But on MRI, high intensity areas on T2 weighted imaging were demonstrated in the cerebral white matter in this group. Many lesions in this group were thought to be edemas of the cerebral white matter, because of the fact that on serial MRI, they were isointense. In mild types of DAI, the lesions on MRI were located only in the cerebral white matter, whereas, in the severe types of DAI, lesions were located in the basal ganglia, the corpus callosum, the dorsal part of the brain stem as well as in the cerebral white matter. As for CT findings, parenchymal lesions were not visualized especially in mild DAI. Our results suggested that the lesions in cerebral concussion were edemas in cerebral white matter. In mild DAI they were non-hemorrhagic contusion; and in severe DAI they were hemorrhagic contusions in the cerebral white matter, the basal ganglia, the corpus callosum or the dorsal part of the brain stem. (author)

First national meeting of magnetic resonance and hyperfine interactions

International Nuclear Information System (INIS)

1985-07-01

Works performed at CNEA's: Magnetic Resonance Division; Moessbauer Spectroscopy; Solid State Physics Division; Nuclear magnetic Resonance Laboratory and Theoretical Physics Group; Mossbauer Spectroscopy Group; Nuclear Quadrupole Resonance; Physics and Materials Group; Perturbed Angular Correlation and Moessbauer Spectroscopy and Physics Department. (M.E.L.) [es

Comparison of Accuracy of Contrast Enhanced Computed Tomography with Accuracy of Non-Contrast Magnetic Resonance Imaging in Evaluation of Local Extension of Base of Tongue Malignancies

Directory of Open Access Journals (Sweden)

Ketan Rathod

2018-01-01

Full Text Available Diagnosis of base of tongue malignancy can be obtained through clinical examination and biopsy. Magnetic Resonance Imaging (MRI and Computed Tomography (CT are used to detect its local extension, nodal spread and distant metastases. The main aim of study was to compare the accuracy of MRI and contrast enhanced CT in determining the local extent of base of tongue malignancy. Twenty five patients, biopsy proven cases of squamous cell carcinoma of base of tongue were taken. 1.5 Tesla Magnetic Resonance Unit with T2 weighted axial, coronal image; T1 weighted axial, coronal image; and STIR (Short tau inversion recovery axial and coronal images were used. 16 slice Computed Tomography unit with non-contrast and contrast enhanced images were used. Accuracy of CT to detect midline crossing: 50%; accuracy of MRI to detect midline crossing: 100%; accuracy of CT to detect anterior extension: 92%; accuracy of MRI to detect anterior extension: 100%; accuracy of CT to detect tonsillar fossa invasion: 83%; accuracy of MRI to detect tonsillar fossa invasion: 100%; accuracy of CT to detect oro pharyngeal spread: 83%; accuracy of MRI to detect oro pharyngeal spread: 100%; accuracy of CT to detect bone involvement: 20%; accuracy of MRI to detect bone involvement: 100%. MRI proved to be a better investigation than CT, in terms of evaluation of depth of invasion, presence of bony involvement, extension to opposite side, anterior half of tongue, tonsillar fossa, floor of mouth or oropharynx.

Magnetic resonance imaging in the evaluation of treatment-related central nervous system damage

International Nuclear Information System (INIS)

Packer, R.J.; Zimmerman, R.A.; Bilaniuk, L.T.

1986-01-01

Neurologic and neuropsychologic treatment related sequelae are increasingly encountered in children with cancer, but conventional means of neurologic investigation are insensitive to the presence and extent of damage. Magnetic resonance imaging (MRI) has shown brain damage not demonstrable by other means of investigation. For this reason, 11 children with cancer and with nontumor-related neurologic dysfunction were studied on a 1.5 Tesla MRI unit. All had concurrent computed tomography (CT). MRI abnormalities were seen in all (100%) patients. In 10 of 11 patients, abnormalities were of greater extent on MRI than on CT. White matter changes were frequently seen on MRI without corresponding CT abnormality. Those patients with the most severe forms of neurologic compromise had the most extensive changes on MRI. Focal neurologic findings correlated well with regions of focal signal change. Milder forms of neurologic compromise occurred in patients with definite, but less extensive, periventricular and/or subcortical change on MRI. MRI is more sensitive than CT in demonstrating treatment-related neurologic damage in children with cancer, and the type of change seen on MRI seems to correlate well with the type and severity of neurologic dysfunction present

Deep-level defects in semiconductors: studies by magnetic resonance

International Nuclear Information System (INIS)

Ammerlaan, C.A.J.

1983-01-01

This work is divided into two parts. In the first one, the following topics are discussed: paramagnetic centers in semiconductors, principles of magnetic resonance, spin-Hamiltonian, g-tensor, hyperfine interaction, magnetic resonance spectrometer. In the second part it is dicussed defects studied by magnetic resonance including vacancy and divacancy in silicon, iron in silicon, nitrogen in diamond and antisite defects in III-V compounds. (A.C.A.S.) [pt

An introduction to magnetic resonance in medicine. 2. rev. ed.

International Nuclear Information System (INIS)

Rinck, P.A.; Muller, R.N.; Petersen, S.B.

1990-01-01

The second edition of this introduction to magnetic resonance in medicine is published five years after the first. During these years, magnetic resonance has established itself as a leading diagnostic modality in medicine. With the introduction of fast imaging methods and contrast agents, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) have become even more complicated and complex than before. The purpose of this introduction to biomedical MRI and MRS is to give the readers a basic knowledge that will make it possible for them to pursue studies of their own and to cope with some of the most common problems such as image artifacts or patient questions concerning possible hazards of magnetic resonance. (orig./MG) With 99 figs., 11 tabs

Controlling interactions between highly magnetic atoms with Feshbach resonances.

Science.gov (United States)

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.

Resonant Magnetization Tunneling in Molecular Magnets: Where is the Inhomogeneous Broadening?

Science.gov (United States)

Friedman, Jonathan R.; Sarachik, M. P.

1998-03-01

Since the discovery(J. R. Friedman, et al., Phys. Rev. Lett. 76), 3830 (1996) of resonant magnetization tunneling in the molecular magnet Mn_12 there has been intense research into the underlying mechanism of tunneling. Most current theories( V. Dobrovitski and A. Zvezdin, Europhys. Lett. 38), 377 (1997); L. Gunther, Europhys. Lett. 39, 1 (1997); D Garanin and E. Chudnovsky, Phys. Rev. B 56, 11102 (1997). suggest that a local internal (hyperfine or dipole) field transverse to the easy magnetization axis induces tunneling. These theories predict a resonance width orders of magnitude smaller than that actually observed. This discrepancy is attributed to inhomogeneous broadening of the resonance by the random internal fields. We present a detailed study of the tunnel resonance lineshape and show that it is Lorentzian, suggesting it has a deeper physical origin. Since the hyperfine fields are believed to be comparable to the observed width, it is surprising that there is no Gaussian broadening.

Capsular contracture and possible implant rupture: is magnetic resonance imaging useful?

Science.gov (United States)

Paetau, Alyssa A; McLaughlin, Sarah A; McNeil, Rebecca B; Sternberg, Erez; TerKonda, Sarvam P; Waldorf, James C; Perdikis, Galen

2010-03-01

Currently, magnetic resonance imaging is considered the accepted standard to evaluate breast implant integrity. To evaluate its utility in diagnosing ruptured silicone implants in the setting of capsular contracture and to correlate the preoperative assessment of implant integrity with or without magnetic resonance imaging with operative findings, 319 capsulectomies (171 patients with capsular contractures) were retrospectively reviewed. Preoperative magnetic resonance imaging was done on 160 implants, whereas the remaining 159 were evaluated using only physical examination and/or mammography. Postoperative results were analyzed to determine the sensitivity, specificity, and accuracy of preoperative magnetic resonance imaging in comparison with clinical and/or mammography evaluation alone. Although occasionally valuable, overall, preoperative magnetic resonance imaging was no more accurate than clinical evaluation with or without mammography in predicting implant status: magnetic resonance imaging 124 of 160 (78 percent) and clinical 121 of 159 (76 percent; p = 0.77). In the setting of capsular contracture, physical examination with or without mammogram is as accurate as magnetic resonance imaging in determining implant integrity. Although magnetic resonance imaging is a sensitive diagnostic tool, in symptomatic patients with capsular contracture, it cannot be viewed as infallible.

SQUID-detected magnetic resonance imaging in microtesla magnetic fields

International Nuclear Information System (INIS)

McDermott, Robert; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Mueck, Michael; Myers, Whittier; Haken, Bernard ten; Seton, H.C.; Trabesinger, Andreas H.; Pines, Alex; Clarke, John

2003-01-01

We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (∼1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a 31P nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and 31P nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm resolution. In further experiments we demonstrate T1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging

Characteristics of Cranial Aneurysmal Bone Cyst on Computed Tomography and Magnetic Resonance Imaging

Directory of Open Access Journals (Sweden)

Sen-Ping Lin

2007-01-01

Full Text Available Aneurysmal bone cysts are benign bone tumors that most commonly occur in people younger than 30 years. The cysts are most often found in the metaphyses of long bones and rarely affect the skull. We present a 54-year-old woman with a rapidly enlarging mass in the left occipital region that caused tenderness for 2 weeks. Computed tomography (CT revealed an expansile, osteolytic lesion with characteristic soap-bubble appearance and fluid-fluid levels. Magnetic resonance images showed a dark rim surrounding the lesion, as well as multilocular spaces with fluid-fluid levels. The tumor was soft, fragile, and pulsatile during surgery. The patient was treated with en bloc resection of the tumor with cranioplasty. Follow-up CT 5 months later showed no evidence of recurrence. [J Formos Med Assoc 2007;106(3:255-259

Magnetic resonance imaging of carbon monoxide poisoning in chronic stage

International Nuclear Information System (INIS)

Kojima, Shigeyuki; Kawamura, Mitsuru; Shibata, Noriyuki; Takahashi, Nobuyoshi; Hirayama, Keizo

1986-01-01

Magnetic resonance imaging (MRI) was evaluated in three patients with carbon monoxide (CO) poisoning in chronic stage by comparison with serial X-ray computed tomography (CT). In Case 1 and 3, no pallidal lesions believed to be the most common lesion of the gray matter in CO poisoning were found in the serial X-ray CT scans. In the other case (Case 2), the typical initial bilateral symmetrical low density areas in the globus pallidus were found to have decreased markedly in size and finally disappeared in the latter X-ray CT scan. But MRI using inversion recovery (IR) or spin echo (SE) pulse sequence clearly showed bilateral symmetrical decreased or increased signal intensity areas in the globus pallidus in all three cases. In Case 3, chronic CO poisoning was confirmed by the bilateral symmetrical pallidal lesions on MRI, although differential diagnosis was difficult. Furthermore, in Case 2, with pure alexia, MRI using IR or SE pulse sequence demonstrated a patchy decreased or increased signal intensity area in the subcortical white matter at the left angular gyrus, although X-ray CT scan showed no abnormal findings. MRI is useful in the diagnosis of CO poisoning, especially chronic CO poisoning, because necrosis, cavitation, demyelination, gliosis and so on due to hypoxia of CO poisoning were sensitively detected from changes in the proton density and the T1 or T2 relaxation time value on MRI. (J.P.N.)

Magnetic resonance of field-frozen and zero-field-frozen magnetic fluids

International Nuclear Information System (INIS)

Pereira, A.R.; Pelegrini, F.; Neto, K. Skeff; Buske, N.; Morais, P.C.

2004-01-01

In this study magnetic resonance was used to investigate magnetic fluid samples frozen under zero and non-zero (15 kG) external fields. The magnetite-based sample containing 2x10 17 particle/cm 3 was investigated from 100 to 400 K. Analysis of the temperature dependence of the resonance field revealed bigger magnetic structures in the frozen state than in the liquid phase. Also, differences in the mesoscopic organization in the frozen state may explain the data obtained from samples frozen under zero and non-zero fields

Magnetic resonance imaging of hypophysis

International Nuclear Information System (INIS)

Malla Huesh, I. V.

2016-01-01

Hypothalamic-pituitary diseases represent with wide variety of symptoms in regard with changes in the endocrine function. Magnetic resonance imaging has a crucial role in detecting the morphologic appearance in physiologic conditions, malformative diseases and acquired pathologies. The MR-imaging is established as the method of choice in assessing the changes in the hypothalamic-pituitary axis. The pituitary gland is a complex structure with an important role in the homeostasis of the organism even though it is so small? It is surrounded by bony structures, vessels, nerves and the brain parenchyma. It consists of three parts - anterior called - adenohypophysis, posterior - neurohypophysis and pituitary stalk. The anterior part comprises about 75% of the gland. Computed tomography (CT) has a limited role in detecting the pituitary gland. It is mainly used in cases of elevated intracranial pressure due to suspected apoplexy. The gland's small size, relation to other structures and its soft tissue characteristic make it an accessible region of interest for detecting with MR-imaging. The lack of ionizing energy and the technical advances in the MR-methods are responsible for the creating images with better spatial resolution and signal to noise ratio. The examination is carried out on a standard protocol. It is important that thin slices are executed in sagittal and coronal planes. Performing a sequence, regarding the brain parenchyma is essential, since many malformations of the pituitary gland are associated with other congenital conditions. The examination starts with a T1W sequence to assess the normal anatomic condition of the gland. The intensity of the adenohypophysis is compared to the one in the pons. It is hypointense, whereas the neurohypophysis is hyperintense, due to the lipid neurosecretory granules transported along the hypothalamic-pituitary axis. T2W-images in coronal plane are used to evaluate the hypothalamus, pituitary stalk, optic chiasm, olfactory

The clinical use of contrast agents in magnetic resonance imaging

International Nuclear Information System (INIS)

Bydder, G.M.

1987-01-01

Interest in the use of external agents to increase tissue contrasts has come from many sources dating back to the earliest work in NMR, to animal studies and to the widespread use of contrast agents in conventional radiological practice. The first clinical magnetic resonance images were published in 1980 and in the following year a brief account of the use of the paramagnetic agents in human volunteers was established. It was apparent relatively early in the development of magnetic resonance imaging (MRI) that a high level of soft tissue contrast was available de novo and the need for externally administered agents might therefore be small. This observation was tempered by the fact that separation of tumour from oedema was frequently better with contrast enhanced CT X-ray than with unenhanced MRI and that of a contrast agent might therefore be needed for MRI. At the end of 1983 the first parenteral agent gadoliminum diethylene triamine pentaacetic acid (Gd-DTPA) was used in volunteers and clinical studies began in 1984. At the present time only molecular O/sub 2/, oral iron compounds and Gd-DTPA are in clinical use although there are a number of other agents which have been used in animals and some of these may become available for clinical use in the foreseeable future

CT and MRT in mediastinal and hilar masses. CT und MRT bei mediastinalen und hilaeren Raumforderungen

Energy Technology Data Exchange (ETDEWEB)

Prayer, L.; Kramer, J.; Stiglbauer, R.; Wimberger, D.; Imhof, H. (Vienna Univ. (Austria). Klinik fuer Radiodiagnostik Ludwig-Boltzmann-Institut fuer Radiologisch-Physikalische Tumordiagnostik, Vienna (Austria)); Metz, V. (Vienna Univ. (Austria). 2. Chirurgische Klinik)

1990-11-01

Thirty-eight patients with mediastinal and/or hilar masses were imaged by computed tomography (CT) and magnetic resonance imaging (MRI). Results were analyzed retrospectively regarding the ability to demonstrate the masses, their number, size, definition, location and tissue characteristics. CT and MRI showed equivalent results in 32 cases; additional information was obtained in two patients by CT, in four patients by MRI. In view of the specific advantages and limitations of both CT and MRI we believed that in patients with mediastinal and/or hilar masses, contrast enhanced CT remains the procedure of choice after performing plain chest radiographs; in certain cases MRI will prove useful for further evaluation. (orig.).

Magnetic resonance, a phenomenon with a great potential in medicine, but with a complex physical background – Part 2: The basics of magnetic resonance

Directory of Open Access Journals (Sweden)

Bojan Božič

2014-01-01

Full Text Available Magnetic resonance imaging is a very complex diagnostic technique. Therefore, both practical experiences and theoretical understanding is needed for effective diagnostics. It is therefore important that physicians are sufficiently familiar with the basic physical principles of magnetic resonance. In the interpretation of physical concepts, we will rely both on the classical as well as on the quantum-mechanical view of the signal formation in magnetic resonance, which are to some extent complementary. The signal appearance in magnetic resonance imaging will be discussed. A special emphasis will be put on the role of the resonance frequency and the pulse sequences. Furthermore, the spin echo as one of the most used classical signal sequences in diagnostic investigations will be described.

Treatment of arteriovenous malformations with stereotactic radiosurgery employing both magnetic resonance angiography and standard angiography as a database

International Nuclear Information System (INIS)

Petereit, D.; Mehta, M.; Turski, P.; Levin, A.; Strother, C.; Mistretta, C.; Mackie, R.; Gehring, M.; Kubsad, S.; Kinsella, T.

1993-01-01

Twenty-one arteriovenous malformations were prospectively evaluated using magnetic resonance angiography, compare it to stereotactic angiography, employ magnetic resonance angiography in follow-up, and semiquanitfy flow. A correlative evaluation between flow and response to stereotactic radiosurgery was carried out. Phase contrast angiograms were obtained at flow velocities of 400, 200, 100, 60 and 20 cm/sec. The fractionated velocities provided images that selectively demonstrated the arterial and venous components of the arteriovenous malformations. Qualitative assessment of the velocity within the arteriovenous malformations and the presence of fistulae were also determined by multiple velocity images. In addition, 3-dimensional time-of-flight magnetic resonance angiograms were obtained to define the exact size and shape of the nidus. This technique also permitted evaluation of the nidus and feeding arteries for the the presence of low flow aneurysms. Correlation between the two imaging modalities was carried out by subjective and semiquantitative estimation of flow velocity and estimation of nidus size. The following velocity parameters were employed: fast, intermediate, slow, and none. Early analysis suggests that slower flowing arteriovenous malformations may obliterate faster after stereotactic radiosurgery an flow parameters should be employed to predict response. In conclusion, magnetic resonance angiography permits semiquantitative flow velocity assessment and may therefore be superior to stereotactic angiography. An additional advantage of magnetic resonance angiography is the generation of serial transverse images which can replace the conventional CT scan employed for stereotactic radiosurgery treatment planning. A single diagnostic test may therefore be used for diagnosis, radiosurgical treatment planning, follow-up, and treatment selection by identifying patients likely to respond early to radiosurgical management

Quantum transport in coupled resonators enclosed synthetic magnetic flux

International Nuclear Information System (INIS)

Jin, L.

2016-01-01

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. -- 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.

Nuclear magnetic resonance scattering

International Nuclear Information System (INIS)

Young, I.R.

1985-01-01

A nuclear magnetic resonance apparatus is described including a magnet system which is capable of providing a steady magnetic field along an axis, and is constructed so as to define a plurality of regions along the axis in each of which the field is substantially homogeneous so that in each region an imaging operation may be separately carried out. Iron shields increase the field homogeneity. In use, each patient lies on a wheeled trolley which is provided with magnetic field gradient coils and an RF coil system, some of the coils being movable to facilitate positioning of the patient, and there are terminals for connection to a common computing and control facility. (author)

21 CFR 892.1000 - Magnetic resonance diagnostic device.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Magnetic resonance diagnostic device. 892.1000 Section 892.1000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance diagnostic...

Nuclear magnetic resonance tomography of the cervical canal

Energy Technology Data Exchange (ETDEWEB)

Terwey, B.; Koschorek, F.; Jensen, H.P.

1985-12-01

170 patients with suspected lesions of the cervical part of the medulla were examined using nuclear magnetic resonance (NMR) tomography. 27 cases revealed no pathological changes in the regions of the cervical medulla, the cervical canal and of the cervical spine. 143 cases produced pathological findings whose diagnoses determined therapeutical approach. Verified pathological changes comprised anomalies of the cranio-cervical junction like basilar impression and Arnold-Chiari malformation, various types of cavity formation in the cervical medulla (syringomyelia, hydromyelia), demyelinization processes, intramedullary and extramedullary tumours, intervertebral disk degeneration processes, dislocation of intervertebral disks and spondylophytes with spinal stenoses. Sagittal sections in different functional positions allowed to demonstrate the biomechanical effects of extramedullary masses on the cervical medulla. However, proven tumours could not be differentiated successfully using histological methods. Nevertheless, NMR tomography will replace invasive methods like conventional cervical myelography and CT myelography in diagnostic clarification of diseases of the cervical medulla.

Comparison between high-field magnetic resonance imaging of the liver and computed tomography. A preliminary study on 39 cases

International Nuclear Information System (INIS)

Demaerel, P.; Marchal, G.; Aerts, P.; Van Fraeyenhoven, L.; Baert, A.L.

1990-01-01

Thirty nine patients with one or more focal hepatic lesions were examined by contrast enhanced computed tomography (CE-CT) and magnetic resonance imaging (MRI). A variety of pulse sequences - spin echo (SE), gradient echo (GE) and inversion recovery (IR) - have been reported in the literature on MRI concerning the detection and characterization of liver tumors. Multiple studies have compared MRI at different field strenghts to CT. As controversy still exists concerning the optimal pulse sequence on MRI, CE-CT has been compared to T2 weighted SE sequence in this study. CT, as well as MRI, identified abnormalities in liver parenchyma in all patients. As far as detection of hepatic lesions is concerned, MRI and CE-CT were equal in 35 cases and MRI was superior in the other four cases. However, CT remains the examination of choice for detection of focal lesions, due to the short examination time, the low cost and the superiority in detection of extrahepatic pathology [fr

Concepts and indications of abdominal magnetic resonance

International Nuclear Information System (INIS)

Murillo Viera, Wendy

2012-01-01

A literature review and conceptualization was performed of the main indications of magnetic resonance studies of the abdomen and the characteristic findings for each sequence, according to organ and pathology. The radiologist has had in mind main indications for magnetic resonance studies of the abdomen, with the purpose to guide the clinician in the choice of imaging modality that works best for the patient at diagnosis [es

Magnetic resonance imaging in the evaluation of periosteal reactions

Energy Technology Data Exchange (ETDEWEB)

Nogueira-Barbosa, Marcello Henrique; Trad, Clovis Simao; Muglia, Valdair Francisco; Elias Junior, Jorge; Simao, Marcelo Novelino, E-mail: marcello@fmrp.usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Centro de Ciencias das Imagens e Fisica Medica; Sa, Jose Luiz de [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Oliveira, Rodrigo Cecilio Vieira de [Clinica de Diagnostico por Imagem Tomoson, Aracatuba, SP (Brazil); Engel, Edgard Eduard [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Biomecanica, Medicina e Reabilitacao do Aparelho Locomotor

2010-07-15

The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods. (author)

Magnetic resonance imaging in the evaluation of periosteal reactions

International Nuclear Information System (INIS)

Nogueira-Barbosa, Marcello Henrique; Trad, Clovis Simao; Muglia, Valdair Francisco; Elias Junior, Jorge; Simao, Marcelo Novelino; Engel, Edgard Eduard

2010-01-01

The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods. (author)

Carcinomatous involvement of the hilum and mediastinum: computed tomographic and magnetic resonance evaluation

International Nuclear Information System (INIS)

Heelan, R.T.; Martini, N.; Westcott, J.W.

1985-01-01

Magnetic resonance (MR) imaging and computed tomography (CT) were compared in 20 patients who had primary lung tumors, and the results were correlated with findings at surgery and pathologic evaluation. Both studies demonstrated a similar ability to detect hilar and mediastinal tumor. MR imaging detected more enlarged nodes in the mediastinum, but in several patients these enlarged nodes did not contain tumor. Consequently, MR imaging has a slightly higher false-positive rate in the evaluation of the mediastinum. Both modalities were highly sensitive, with specificity limited by the presence of enlarged benign lymph nodes in this series of patients

Nuclear resonance apparatus including means for rotating a magnetic field

International Nuclear Information System (INIS)

Sugimoto, H.

1983-01-01

A nuclear magnetic resonance apparatus including magnet apparatus for generating a homogeneous static magnetic field between its magnetic poles, shims of a magnetic substance mounted on the magnetic poles to apply a first gradient magnetic field intensity distribution in a direction orthogonal as to the direction of line of magnetic force of the static magnetic field, gradient magnetic field generating electromagnetic apparatus for generating a second gradient magnetic field having a gradient magnetic field intensity distribution in superimposition with the static magnetic field and for changing the magnetic field gradient of the first gradient magnetic field, an oscillator for generating an oscillating output having a frequency corresponding to the nuclear magnetic resonance condition of an atomic nucleus to be measured, a coil wound around a body to be examined for applying the output of said oscillator as electromagnetic waves upon the body, a receiver for detecting the nuclear magnetic resonance signals received by the coil, a gradient magnetic field controller making a magnetic field line equivalent to the combined gradient magnetic fields and for rotating the line along the section of the body to be examined by controlling said gradient magnetic field generating electromagnetic apparatus and devices for recording the nuclear magnetic resonance signals, for reconstructing the concentration distribution of the specific atomic nuclei in the section of the body, and a display unit for depicting the result of reconstruction

Resonance magnetic x-ray scattering study of erbium

DEFF Research Database (Denmark)

Sanyal, M.K.; Gibbs, D.; Bohr, J.

1994-01-01

The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...... of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior of the magnetic...

Magnetic Resonance Cholangiopancreatography (MRCP)

Science.gov (United States)

... radio waves and a computer to evaluate the liver, gallbladder, bile ducts, pancreas and pancreatic duct for disease. It is ... of the hepatobiliary and pancreatic systems, including the liver, gallbladder, bile ducts, pancreas and pancreatic duct . Magnetic resonance imaging (MRI) ...

Magnetic resonance imaging of olfactory neuroblastoma

International Nuclear Information System (INIS)

Iio, Mitsuhiro; Homma, Akihiro; Furuta, Yasushi; Fukuda, Satoshi

2006-01-01

Olfactory neuroblastoma is an uncommon intranasal tumor originating from olfactory neuroepithelium. Despite the development of electron microscopy and immunohistochemical testing, the pathological diagnosis of this tumor is still difficult because of the wide range of histological features. Magnetic resonance imaging (MR) of this tumor and the pattern of contrast enhancement have not been well described. The purpose of this report was to analyze the MR characteristics of olfactory neuroblastomas. The MR signal, pattern of contrast enhancement, and correlation with high-resolution computed tomography (CT) imaging were examined. Seventeen patients with olfactory neuroblastoma were treated at Hokkaido University Hospital and a related hospital during the past 25 years. MR images taken in 12 patients and CT images taken in 9 patients with histologically confirmed olfactory neuroblastoma were retrospectively reviewed. Compared with brain gray matter, 11 tumors were hypointense on T1-weighted images, 9 homogeneously and 2 heterogeneously. Eight tumors were hyperintense on T2-weighted images, 3 homogeneously and 5 heterogeneously, although their appearance was less intense than that of sinusitis. Gadolinium enhancement was moderate in one case and marked in 10 of the 11 cases, 9 homogeneously and 2 heterogeneously. Nine of the 11 tumors showed smooth regular shaped margins; 2 of these tumors exhibited irregular infiltrating margins on gadolinium-enhanced images, compared to the pre-contrast T1-weighted images. Eight of the 11 tumors had clearly demarcated margins, while 3 of the 11 tumors did not exhibit gadolinium enhancement. Six of the 12 cases (50%) exhibited intracranial cysts on the gadolinium-enhanced images. T2-weighted or gadolinium-enhanced images successfully distinguished sinusitis from tumors in 4 cases whereas the CT images failed. Gadolinium enhancement, particularly in the tangential plane, demonstrated intracranial extension not apparent on the CT images

Science Drivers and Technical Challenges for Advanced Magnetic Resonance

Energy Technology Data Exchange (ETDEWEB)

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.

Use of magnetic resonance imaging in the evaluation of spondylolysis.

Science.gov (United States)

Rush, Jeremy K; Astur, Nelson; Scott, Stephanie; Kelly, Derek M; Sawyer, Jeffrey R; Warner, William C

2015-01-01

In early studies, magnetic resonance imaging (MRI) had low sensitivity and positive predictive value in the evaluation of the pars interarticularis pathology; however, more recent reports have suggested an expanded role for MRI. The purpose of the present study was to evaluate the effectiveness of MRI in the diagnosis of pars injuries and compare it to computed tomography (CT), which was used as the reference "gold standard" for the detection of fractures. The radiographic and clinic data of 93 adolescents and young adults with a presumptive diagnosis of spondylolysis based upon history and clinic examination were reviewed. Only 26 patients who had MRI and CT images obtained within 30 days of each other were included. All images were reviewed by a fellowship-trained musculoskeletal radiologist and fellowship-trained pediatric orthopaedist. Overall, 39 individual pars lesions (stress reaction or fracture) were identified. MRI was effective in identifying 36 pars lesions. MRI identified 11 lesions in 9 patients with negative CT. Seven of these lesions were stress reactions (grade 1), whereas 4 were frank fractures. Three pars injuries were noted on CT while the MRI was negative. MRI is an effective method (92% sensitivity) for detecting pars injuries. It can detect stress reactions when a fracture is not visible on CT scan, allowing early treatment of these prelysis lesions. The 92% sensitivity of MRI is comparable with that of other diagnostic modalities such as bone scan, with the advantage of no radiation exposure. MRI should be strongly considered as the advanced imaging modality of choice in the evaluation of patients with suspected spondylolysis. Level III-diagnostic study.

Definition of the prostate in CT and MRI: a multi-observer study

NARCIS (Netherlands)

Rasch, C.; Barillot, I.; Remeijer, P.; Touw, A.; van Herk, M.; Lebesque, J. V.

1999-01-01

To determine, in three-dimensions, the difference between prostate delineation in magnetic resonance (MR) and computer tomography (CT) images for radiotherapy treatment planning. Three radiation oncologists, considered experts in the field, outlined the prostate without seminal vesicles both on CT,

Frequency-domain analysis of resonant-type ring magnet power supplies

International Nuclear Information System (INIS)

Kim, J.M.S.; Reiniger, K.W.

1993-01-01

For fast-cycling synchrotrons, resonant-type ring magnet power supplies are commonly used to provide a dc-biased ac excitation for the ring magnets. Up to the present, this power supply system has been analyzed using simplified analytical approximation, namely assuming the resonant frequency of the ring magnet network is fixed and equal to the accelerator frequency. This paper presents a frequency-domain analysis technique for a more accurate analysis of resonant-type ring magnet power supplies. This approach identifies that, with the variation of the resonant frequency, the operating conditions of the power supply changes quite dramatically because of the high Q value of the resonant network. The analytical results are verified, using both experimental results and simulation results

Resonant cell of a double nuclear electron resonance spectrometer for performance in a 120-350 Gs magnetic field

International Nuclear Information System (INIS)

Baldin, V.I.; Stepanov, A.P.

1976-01-01

Spectrometer double-frequency resonance cell construction of a double nuclear electron resonance for operation in 120-350 Gs magnetic fields is described. The cell has been developed from a special decimeter resonator with a concentrated capacitance. The electric and magnetic components of a high frequency field are efficiently divided in the separator. Therefore, the insertion of a measuring coil and a sample in the maximum of the magnetic component of the field does not practically affect the distribution and parameters of the high-frequency field. The double-frequency resonance cell proposed provides for a higher accuracy of measuring amplifications of the nuclear magnetic resonance signals when there is the overhauzer effect for 120-350 Gs magnetic fields

Can magnetic resonance imaging differentiate undifferentiated arthritis?

DEFF Research Database (Denmark)

Østergaard, Mikkel; Duer, Anne; Hørslev-Petersen, K

2005-01-01

A high sensitivity for the detection of inflammatory and destructive changes in inflammatory joint diseases makes magnetic resonance imaging potentially useful for assigning specific diagnoses, such as rheumatoid arthritis and psoriatic arthritis in arthritides, that remain undifferentiated after...... conventional clinical, biochemical and radiographic examinations. With recent data as the starting point, the present paper describes the current knowledge on magnetic resonance imaging in the differential diagnosis of undifferentiated arthritis....

Effect of resonance line shape on precision measurements of nuclear magnetic resonance shifts

International Nuclear Information System (INIS)

Kachurin, A.M.; Smelyanskij, A.Ya.

1986-01-01

Effect of resonance line shape on the systematic error of precision measurements of nuclear magnetic resonance (NMR) shifts of high resolution (on the center of NMR dispersion line) is analysed. Effect of the device resonance line form-function asymmetry is evaluated; the form-function is determined by configuration of the spectrometer magnetic field and enters the convolution, which describes the resonance line form. It is shown that with the increase of the relaxation line width the form-function effect on the measurement error yields to zero. The form-function effect on measurements and correction of a phase angle of NMR detection is evaluated. The method of semiquantitative evaluation of resonance line and NMR spectrometer parameters, guaranteeing the systematic error of the given infinitesimal, is presented

Magnetic resonance imaging of infectious myositis

Energy Technology Data Exchange (ETDEWEB)

Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha [The Catholic Univ., College of Medicine, Suwon (Korea, Republic of)

1998-09-01

To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

Magnetic resonance imaging of infectious myositis

International Nuclear Information System (INIS)

Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha

1998-01-01

To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

FDG-PET in the diagnosis of neuropsychiatric Lupus erythematosus and comparison with computed tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Stoppe, G.; Wildhagen, K.; Meyer, G.J.; Schober, O.

1989-01-01

Central nervous system involvement has been found in 30-75% of all cases of systemic lupus erythematosus (SLE). Up to now, clinical diagnosis is difficult and there are no markers for disease activity. We have compared cranial computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) using fluorodesoxyglucose (FDG) in two cases. FDG-PET is shown to be the most sensitive method demonstrating even reversible deficits and a better correlation with other neurological findings. MRI seems to be more sensitive than CT. A survey of the literature concerning imaging methods in neuropsychiatric SLE is given. The special problem of neuronal desactivation by antineuronal activity is discussed. (orig.) [de

Molecular structure and motion in zero field magnetic resonance

International Nuclear Information System (INIS)

Jarvie, T.P.

1989-10-01

Zero field magnetic resonance is well suited for the determination of molecular structure and the study of motion in disordered materials. Experiments performed in zero applied magnetic field avoid the anisotropic broadening in high field nuclear magnetic resonance (NMR) experiments. As a result, molecular structure and subtle effects of motion are more readily observed

Diagnostic imaging of psoriatic arthritis. Part II: magnetic resonance imaging and ultrasonography

Directory of Open Access Journals (Sweden)

Iwona Sudoł-Szopińska

2016-06-01

Full Text Available Plain radiography reveals specific, yet late changes of advanced psoriatic arthritis. Early inflammatory changes are seen both on magnetic resonance imaging and ultrasound within peripheral joints (arthritis, synovitis, tendons sheaths (tenosynovitis, tendovaginitis and entheses (enthesitis, enthesopathy. In addition, magnetic resonance imaging enables the assessment of inflammatory features in the sacroiliac joints (sacroiliitis, and the spine (spondylitis. In this article, we review current opinions on the diagnostics of some selective, and distinctive features of psoriatic arthritis concerning magnetic resonance imaging and ultrasound and present some hypotheses on psoriatic arthritis etiopathogenesis, which have been studied with the use of magnetic resonance imaging. The following elements of the psoriatic arthritis are discussed: enthesitis, extracapsular inflammation, dactylitis, distal interphalangeal joint and nail disease, and the ability of magnetic resonance imaging to differentiate undifferentiated arthritis, the value of whole-body magnetic resonance imaging and dynamic contrast-enhanced magnetic resonance imaging.

Magnetic resonance spectroscopy as a diagnostic modality for carcinoma thyroid

International Nuclear Information System (INIS)

Gupta, Nikhil; Kakar, Arun K.; Chowdhury, Veena; Gulati, Praveen; Shankar, L. Ravi; Vindal, Anubhav

2007-01-01

Aim: The aim of this study was to observe the findings of magnetic resonance spectroscopy of solitary thyroid nodules and its correlation with histopathology. Materials and methods: In this study, magnetic resonance spectroscopy was carried out on 26 patients having solitary thyroid nodules. Magnetic resonance spectroscopy (MRS) was performed on a 1.5 T super conductive system with gradient strength of 33 mTs. Fine needle aspiration cytology was done after MRS. All 26 patients underwent surgery either because of cytopathologically proven malignancy or because of cosmetic reasons. Findings of magnetic resonance spectroscopy were compared with histopathology of thyroid specimens. Results and conclusion: It was seen that presence or absence of choline peak correlates very well with presence or absence of malignant foci with in the nodule (sensitivity = 100%; specificity = 88.88%). These results indicate that magnetic resonance spectroscopy may prove to be an useful diagnostic modality for carcinoma thyroid

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

Science.gov (United States)

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. Copyright © 2014 Elsevier España, S.L. All rights reserved.

Magnetic resonance imaging and neurolupus

International Nuclear Information System (INIS)

Schott, A.M.; Colson, F.; Tebib, J.; Noel, E.; Bouvier, M.

1990-01-01

Magnetic resonance imaging (MRI) was assessed in the management of neuropsychiatric manifestations occurring in 6 SLE patients. The MRI scans were normal in 3 cases and was associated with remission of the symptoms except for a patient who experienced a chorea at the time of the examination. Abnormal MRI scans always revealed more lesions than CT scan. 2 different patterns of abnormalities seem to correspond to 2 specific disorders. In 2 patients with clinical presentation suggesting a cortical ischemia by vascular thrombosis, both MRI scans showed areas of abnormal high signal intensities located in the subcortical white matter. In one last patient, MRI scan revealed multiple focal areas of high signal intensities (on T 1 weighter scans) disseminated not only in the deep white matter but also in the gray one. These lesions could be depend upon demyelinisation which may occur by a local vascular process. This serie confirms the interest of MRI in the management of SLE brain involvement as well as it points out some problem of interpretation. This suggest further comparative studies especially at the real onset and during the course of neuro-psychiatric manifestations. At last, the coronal sections may be more informative for the diagnosis and patholophysiology than the horizontal ones [fr

Magnetic resonance, especially spin echo, in spinor Bose-Einstein condensates

International Nuclear Information System (INIS)

Yasunaga, Masashi; Tsubota, Makoto

2009-01-01

Magnetic resonance, especially NMR and ESR, has been studied in magnetic materials for a long time, having been used in various fields. Spin echo is typical phenomenon in magnetic resonance. The magnetic resonance should be applied to spinor Bose-Einstein condensates (BECs). We numerically study spin echo of a spinor BEC in a gradient magnetic field by calculating the spin-1 two-dimensional Gross-Pitaevskii equations, obtaining the recovery of the signal of the spins, which is called spin echo. We will discuss the relation between the spin echo and the Stern-Gelrach separation in the system.

Magnetic Resonance Imaging Studies of Postpartum Depression: An Overview

Directory of Open Access Journals (Sweden)

Marco Fiorelli

2015-01-01

Full Text Available Postpartum depression is a frequent and disabling condition whose pathophysiology is still unclear. In recent years, the study of the neural correlates of mental disorders has been increasingly approached using magnetic resonance techniques. In this review we synthesize the results from studies on postpartum depression in the context of structural, functional, and spectroscopic magnetic resonance studies of major depression as a whole. Compared to the relative wealth of data available for major depression, magnetic resonance studies of postpartum depression are limited in number and design. A systematic literature search yielded only eleven studies conducted on about one hundred mothers with postpartum depression overall. Brain magnetic resonance findings in postpartum depression appear to replicate those obtained in major depression, with minor deviations that are not sufficient to delineate a distinct neurobiological profile for this condition, due to the small samples used and the lack of direct comparisons with subjects with major depression. However, it seems reasonable to expect that studies conducted in larger populations, and using a larger variety of brain magnetic resonance techniques than has been done so far, might allow for the identification of neuroimaging signatures for postpartum depression.

Quantitative magnetic resonance micro-imaging methods for pharmaceutical research.

Science.gov (United States)

Mantle, M D

2011-09-30

The use of magnetic resonance imaging (MRI) as a tool in pharmaceutical research is now well established and the current literature covers a multitude of different pharmaceutically relevant research areas. This review focuses on the use of quantitative magnetic resonance micro-imaging techniques and how they have been exploited to extract information that is of direct relevance to the pharmaceutical industry. The article is divided into two main areas. The first half outlines the theoretical aspects of magnetic resonance and deals with basic magnetic resonance theory, the effects of nuclear spin-lattice (T(1)), spin-spin (T(2)) relaxation and molecular diffusion upon image quantitation, and discusses the applications of rapid magnetic resonance imaging techniques. In addition to the theory, the review aims to provide some practical guidelines for the pharmaceutical researcher with an interest in MRI as to which MRI pulse sequences/protocols should be used and when. The second half of the article reviews the recent advances and developments that have appeared in the literature concerning the use of quantitative micro-imaging methods to pharmaceutically relevant research. Copyright © 2010 Elsevier B.V. All rights reserved.

Comparative analysis of nuclear magnetic resonance well logging and nuclear magnetic resonance mud logging

International Nuclear Information System (INIS)

Yuan Zugui

2008-01-01

The hydrogen atoms in oil and water are able to resonate and generate signals in the magnetic field, which is used by the NMR (nuclear magnetic resonance) technology in petroleum engineering to research and evaluate rock characteristics. NMR well logging was used to measure the physical property parameters of the strata in well bore, whereas NMR mud logging was used to analyze (while drilling) the physical property parameters of cores, cuttings and sidewall coring samples on surface (drilling site). Based on the comparative analysis of the porosity and permeability parameters obtained by NMR well logging and those from analysis of the cores, cuttings and sidewall coring samples by NMR mud logging in the same depth of 13 wells, these two methods are of certain difference, but their integral tendency is relatively good. (authors)

Occult primary tumors of the head and neck: accuracy of thallium 201 single-photon emission computed tomography and computed tomography and/or magnetic resonance imaging

NARCIS (Netherlands)

van Veen, S. A.; Balm, A. J.; Valdés Olmos, R. A.; Hoefnagel, C. A.; Hilgers, F. J.; Tan, I. B.; Pameijer, F. A.

2001-01-01

To determine the accuracy of thallium 201 single-photon emission computed tomography (thallium SPECT) and computed tomography and/or magnetic resonance imaging (CT/MRI) in the detection of occult primary tumors of the head and neck. Study of diagnostic tests. National Cancer Institute, Amsterdam,

Magnetic resonance tomography for trauma of the cervical spine

International Nuclear Information System (INIS)

Meydam, K.; Sehlen, S.; Schlenkhoff, D.; Kiricuta, J.C.; Beyer, H.K.

1986-01-01

Twenty patients who had suffered spinal trauma were examined by magnetic resonance tomography. Fifteen patients with first degree trauma in Erdmann's classification showed no abnormality. Magnetic resonance tomography of the cervical spine appears to be a suitable method for investigating patients with whiplash injuries. It is indicated following severe flexion injuries with subluxations and neurological symptoms, since it is the only method that can demonstrate the spinal cord directly and completely and show the extent of cord compression. For patients with thoracic trauma and rapidly developing neurological symptoms, magnetic resonance tomography is ideal for showing post-traumatic syringomyelia. Magnetic resonance tomography following whiplash injuries is recommended if plain films of the cervical spine show any abnormalities, as well as for the investigation of acute or sub-acute neurological abnormalities. The various findings are discussed. (orig.) [de

Magnetic resonance tomography for trauma of the cervical spine

Energy Technology Data Exchange (ETDEWEB)

Meydam, K.; Sehlen, S.; Schlenkhoff, D.; Kiricuta, J.C.; Beyer, H.K.

1986-12-01

Twenty patients who had suffered spinal trauma were examined by magnetic resonance tomography. Fifteen patients with first degree trauma in Erdmann's classification showed no abnormality. Magnetic resonance tomography of the cervical spine appears to be a suitable method for investigating patients with whiplash injuries. It is indicated following severe flexion injuries with subluxations and neurological symptoms, since it is the only method that can demonstrate the spinal cord directly and completely and show the extent of cord compression. For patients with thoracic trauma and rapidly developing neurological symptoms, magnetic resonance tomography is ideal for showing post-traumatic syringomyelia. Magnetic resonance tomography following whiplash injuries is recommended if plain films of the cervical spine show any abnormalities, as well as for the investigation of acute or sub-acute neurological abnormalities. The various findings are discussed.

Normal perinatal and paediatric postmortem magnetic resonance imaging appearances

Energy Technology Data Exchange (ETDEWEB)

Arthurs, Owen J. [Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); UCL Institute of Child Health, London (United Kingdom); Barber, Joy L. [Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); Taylor, Andrew M. [Cardiorespiratory Division, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); UCL Institute of Cardiovascular Science, Centre for Cardiovascular Imaging, London (United Kingdom); Sebire, Neil J. [UCL Institute of Child Health, London (United Kingdom); Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom)

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. (orig.)

Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils

Science.gov (United States)

Hanvey, S.; Glegg, M.; Foster, J.

2009-09-01

This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

Topical questions in magnetic resonance imaging

International Nuclear Information System (INIS)

Andrew, E.R.; Florida Univ., Gainesville, FL; Florida Univ., Gainesville, FL

1989-01-01

This paper examines a number of practical questions concerning magnetic resonance imaging. These include the choice of operating magnetic field strength, the problem of siting and screening, a procedure for securing precise slice selection and the use of paramagnetic contrast agents. (author). 5 refs

'Blocking' effects in magnetic resonance? The ferromagnetic nanowires case

International Nuclear Information System (INIS)

Ramos, C.A.; De Biasi, E.; Zysler, R.D.; Vassallo Brigneti, E.; Vazquez, M.

2007-01-01

We present magnetic resonance results obtained at L, X, and Q bands (1.2, 9.4 and 34GHz, respectively) on ferromagnetic nanowires with a hysteresis cycle characterized by a remanent magnetization M r /M s ∼0.92 and a coercive field H c =1.0kOe. The hysteretic response of the ferromagnetic resonance spectra is discussed in terms of independent contributions of the nanowires aligned along and opposite to the applied field. We will discuss the implications of this study on the magnetic resonance in nanoparticles and other systems with large anisotropy

Recent trends in high spin sensitivity magnetic resonance

Science.gov (United States)

Blank, Aharon; Twig, Ygal; Ishay, Yakir

2017-07-01

Magnetic resonance is a very powerful methodology that has been employed successfully in many applications for about 70 years now, resulting in a wealth of scientific, technological, and diagnostic data. Despite its many advantages, one major drawback of magnetic resonance is its relatively poor sensitivity and, as a consequence, its bad spatial resolution when examining heterogeneous samples. Contemporary science and technology often make use of very small amounts of material and examine heterogeneity on a very small length scale, both of which are well beyond the current capabilities of conventional magnetic resonance. It is therefore very important to significantly improve both the sensitivity and the spatial resolution of magnetic resonance techniques. The quest for higher sensitivity led in recent years to the development of many alternative detection techniques that seem to rival and challenge the conventional ;old-fashioned; induction-detection approach. The aim of this manuscript is to briefly review recent advances in the field, and to provide a quantitative as well as qualitative comparison between various detection methods with an eye to future potential advances and developments. We first offer a common definition of sensitivity in magnetic resonance to enable proper quantitative comparisons between various detection methods. Following that, up-to-date information about the sensitivity capabilities of the leading recently-developed detection approaches in magnetic resonance is provided, accompanied by a critical comparison between them and induction detection. Our conclusion from this comparison is that induction detection is still indispensable, and as such, it is very important to look for ways to significantly improve it. To do so, we provide expressions for the sensitivity of induction-detection, derived from both classical and quantum mechanics, that identify its main limiting factors. Examples from current literature, as well as a description of

Bayesian estimation of multicomponent relaxation parameters in magnetic resonance fingerprinting.

Science.gov (United States)

McGivney, Debra; Deshmane, Anagha; Jiang, Yun; Ma, Dan; Badve, Chaitra; Sloan, Andrew; Gulani, Vikas; Griswold, Mark

2018-07-01

To estimate multiple components within a single voxel in magnetic resonance fingerprinting when the number and types of tissues comprising the voxel are not known a priori. Multiple tissue components within a single voxel are potentially separable with magnetic resonance fingerprinting as a result of differences in signal evolutions of each component. The Bayesian framework for inverse problems provides a natural and flexible setting for solving this problem when the tissue composition per voxel is unknown. Assuming that only a few entries from the dictionary contribute to a mixed signal, sparsity-promoting priors can be placed upon the solution. An iterative algorithm is applied to compute the maximum a posteriori estimator of the posterior probability density to determine the magnetic resonance fingerprinting dictionary entries that contribute most significantly to mixed or pure voxels. Simulation results show that the algorithm is robust in finding the component tissues of mixed voxels. Preliminary in vivo data confirm this result, and show good agreement in voxels containing pure tissue. The Bayesian framework and algorithm shown provide accurate solutions for the partial-volume problem in magnetic resonance fingerprinting. The flexibility of the method will allow further study into different priors and hyperpriors that can be applied in the model. Magn Reson Med 80:159-170, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Low field magnetic resonance experiments in superfluid 3He--A

International Nuclear Information System (INIS)

Gully, W.J. Jr.

1976-01-01

Measurements of the longitudinal and transverse nuclear magnetic resonance signals have been made on the A phase of liquid 3 He. They were performed on a sample of 3 He self-cooled by the Pomeranchuk effect to the critical temperature of the superfluid at 2.7 m 0 K. The longitudinal resonance is a magnetic mode of the liquid excited by radio frequency magnetic fields applied in the direction of the static magnetic field. Frequency profiles of this resonance were indirectly obtained by contour techniques from signals recorded by sweeping the temperature. Its frequency is found to be related to the frequency shift of the transverse resonance in agreement with theoretical predictions for the ABM pairing state. Its linewidth also agrees with theoretical predictions based upon dissipative phenomena peculiar to the superfluid phase. An analysis of the linewidth of the longitudinal resonance yields a value for the quasiparticle collision time. Transverse NMR lines were also studied. In low magnetic fields (20 Oersted) these lines were found to become extremely broad. This is shown to be a manifestation of the same collisional processes that broaden the longitudinal resonance lines. Also, the effects of various textures on the resonance lines are discussed, including the results of an attempt to create a single domain of 3 He with crossed electric and magnetic fields

Nuclear magnetic resonance in ferromagnetic terbium metal

International Nuclear Information System (INIS)

Cha, C.L.T.

1974-01-01

The magnetic properties of terbium were studied by the method of zero field nuclear magnetic resonance at 1.5 to 4 and 85 to 160 0 K. Two unconventional experimental techniques have been employed: the swept frequency and the swept temperature technique. Near 4 0 K, triplet resonance line structures were found and interpreted in terms of the magnetic domain and wall structures of ferromagnetic terbium. In the higher temperature range, temperature dependence of the resonance frequency and the quadrupole splitting were measured. The former provides a measurement of the temperature dependence of the magnetization M, and it agrees with bulk M measurements as well as the latest spin wave theory of M(T) (Brooks 1968). The latter agrees well with a calculation using a very general single ion density matrix for collective excitations (Callen and Shtrikman 1965). In addition, the small temperature-independent contribution to the electric field gradient at the nucleus due to the lattice and conduction electrons was untangled from the P(T) data. Also an anomalous and unexplained relaxation phenomenon was also observed

Nuclear magnetic resonance tomography of the cervical canal

International Nuclear Information System (INIS)

Terwey, B.; Koschorek, F.; Jensen, H.P.

1985-01-01

170 patients with suspected lesions of the cervical part of the medulla were examined using nuclear magnetic resonance (NMR) tomography. 27 cases revealed no pathological changes in the regions of the cervical medulla, the cervical canal and of the cervical spine. 143 cases produced pathological findings whose diagnoses determined therapeutical approach. Verified pathological changes comprised anomalies of the cranio-cervical junction like basilar impression and Arnold-Chiari malformation, various types of cavity formation in the cervical medulla (syringomyelia, hydromyelia), demyelinization processes, intramedullary and extramedullary tumours, intervertebral disk degeneration processes, dislocation of intervertebral disks and spondylophytes with spinal stenoses. Sagittal sections in different functional positions allowed to demonstrate the biomechanical effects of extramedullary masses on the cervical medulla. However, proven tumours could not be differentiated successfully using histological methods. Nevertheless, NMR tomography will replace invasive methods like conventional cervical myelography and CT myelography in diagnostic clarification of diseases of the cervical medulla. (orig.) [de

Development of nuclear magnetic resonance tomography technology - TORM

International Nuclear Information System (INIS)

Tannus, A.

1987-01-01

The development of hardware and software necessary to implement the Magnetic Resonance Imaging (MRI) techniques is described. The major subjects were the construction of an aquisition and control system which allowed the operation of a pulsed Fourier NMR spectrometer as a NMR Tomograph; further it was oriented the developing of a NMR spectrometer whose parameters could be easily reconfigured by the controlling system. As a result a sofisticated equipment which allows, more than the proposed, working with high resolution spectroscopic techniques and spectroscopy in solids, was obtained. Since the basic techniques employed in NMR and CT Tomographs are well known, a great emphasis was also given on the understanding of the image reconstruction techniques that constitutes today the frontier of research in this area. The results obtained with the system described here are considered good, comparable to the results from commercial units developed in cooperation with imaging groups located in universities abroad. (author) [pt

Gadolinium-DTPA in magnetic resonance tomography

International Nuclear Information System (INIS)

Prayer, L.; Imhof, H.; Stiglbauer, R.; Kramer, J.; Wimberger, D.

1989-01-01

Magnetic resonance tomography was performed on 158 patients with different indications before and after the administration of contrast medium. The MR examination included various plain T 1 and T 2 weighted spin echo sequences as well as T 1 weighted examinations after intravenous application of gadolinium-DTPA ('Magnevist', Schering AG) in a dosage of 0.1 mmol/kg body weight. The following conclusions were drawn: The sensitivity of MR in detecting brain tumors, acoustic neuromas and pituitary adenomas was improved considerably after the administration of 'Magnevist'. To diagnose the type of tumor, the criteria which apply to Gd-DPTA are similar to those used for iodine-containing contrast medium in CT. In about 2/3 rds of the cases, delineation of pathological tissues from surrounding edema and normal structures was better than in plain films. Hence, accurate, pretherapeutic staging of bronchial carcinomas and an exact definition of the expansion of the malignancies in the muscle-skeleton system were possible. In respect of tumors in the region of the base of the skull, we could omit T 2 -weighted sequences without noticeable loss of diagnostically relevant information; the examination time could thus be shortened by about 12 minutes. (orig.) [de

Magnetic resonance imaging in multiple sclerosis

International Nuclear Information System (INIS)

Kojima, Shigeyuki; Hirayama, Keizo

1989-01-01

Magnetic resonance imaging (MRI) of the brain was performed in a total of 45 patients with multiple sclerosis (MS), comprising 27 with brain symptoms and 18 without it. The results were compared with X-ray computed tomography (CT). Some of the 45 MS patients were also examined by neurophysiological studies for comparison. MRI showed demyelinating plaques of the brain in a total of 31 patients (69%) - 20 symptomatic and 11 asymptomatic patients. For symptomatic patients, MRI was capable of detecting brain lesions in 6 (86%) of 7 acute stage patients and 14 (70%) of 20 non-acute stage patients. It was also capable of detecting brain lesions in 21 (70%) of 30 clinically definite MR patients and 10 (67%) of 15 clinically probable MS patients. Concurrently available X-ray CT revealed brain lesions in 9 symptomatic patients (33%) and one asymptomatic patient (6%). Visual evoked potentials examined in 31 patients showed abnormality in one (11%) of 9 patients without symptoms of optic neuritis and all (100%) of the other 22 patients with symptoms. In 19 evaluable patients, auditory brainstem responses were abnormal in one (11%) of 9 patients without brainstem symptoms and 3 (30%) of 10 patients with symptoms. MRI of the brain was far superior to X-ray CT, visual evoked potentials and auditory brainstem responses in detecting clinically unsuspected lesions. We proposed new diagnostic criteria including MRI findings of the brain in the Japanese MS diagnostic criteria. MRI of the spinal cord was performed in 12 MS patients with spinal cord symptoms by sagittal and coronal images. It demonstrated demyelinating lesions within the cervical and superior thoracic cord in 8 MS acute stage patients. Spinal cord lesions were longitudinally continuous as long as many spinal segments, with swelling in 6 patients and atrophy in 2 patients. MRI of spinal cord was useful in deciding superior and inferior limits of cord lesions and in visualizing cord swelling or atrophy. (Namekawa, K)

Functional Magnetic Resonance Imaging

Science.gov (United States)

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…

Moessbauer and magnetic resonance experiments on amorphous iron-silicon films

International Nuclear Information System (INIS)

Bansal, C.; Campbell, S.J.; Stewart, A.M.

1982-01-01

Moessbauer measurements at room temperature and 4.2 K, and room temperature magnetic resonance measurments on a series of amorphous Fesub(x)Sisub(1-x) thin films (0.23 <= x <= 0.81) are presented. The concentration dependence of the isomer shifts and quadrupole splittings provides information on the nature of the local coordination in these amorphous materials. Analysis of the distributions of magnetic hyperfine splitting combined with the presence of multiple resonance in the magnetic resonance data indiates that magnetoanisotropy plays a dominant role in determining the magnetic behaviour of these films. (orig.)

Magnetic resonance imaging

International Nuclear Information System (INIS)

Sigal, R.

1988-01-01

This book is an introduction to magnetic resonance imaging (MRI). The basic principles for the interpretation of MR images are developed. The book is divided into five chapters: introduction, tissue, parameters, acquisition parameters, contribution to diagnosis, and practical management of an MR examination. Eight exercises allow the reader to test the knowledge he has acquired. Signal localization and MR artefacts are reviewed in an appendix

Children's (Pediatric) CT (Computed Tomography)

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Full Text Available ... Sometimes ultrasound is substituted for CT as a method of imaging in these procedures in children. A diagnosis ... 450 pounds—for the moving table. Other imaging methods such as ultrasound or magnetic resonance (MR) imaging can provide pictures of certain areas of the body that sometimes are ...

On effect of stability of magnetic resonance position by harmonized field

International Nuclear Information System (INIS)

Ivanchenko, E.A.; Tolstoluzhsky, A.P.

2006-01-01

The formalism of density matrix in a two level system is used to study the time-periodic modulation of the magnetic field stabilizating the magnetic resonance position. An exact solution for density matrix at resonance is found. It is shown that the fundamental resonance is stable with respect to consistent variations of longitudinal and transversal magnetic fields. A differential equation for the transition probability is obtained. The dependence of time-averaged spin flip probability on the normalized Larmor frequency was numerically researched in different parameter regimes with account of dissipation and decoherence. It is shown that the position of the main resonance is independent of field deformation and dissipation; only the width of resonance line changes upon field deformation and dissipation. The odd parametric (multi-photon) resonance transitions is studied. Static magnetization induced by time-periodic modulated magnetic field is considered. The results of the investigation may be useful for analysis of interference experiments, improvement of magnetic spectrometers and in the field of quantum computing manipulation of q-bits

Diagnostic evaluation of ischemic heart disease by X-ray computed tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Masuda, Yoshiaki; Kobayashi, Shiro; Takasu, Junichiro; Sakakibara, Makoto; Imai, Hitoshi; Aoyagi, Yutaka; Morooka, Nobuhiro; Watanabe, Shigeru; Inagaki, Yoshiaki

1987-01-01

To assess the usefulness of X-ray computed tomography (CT) and magnetic resonance imaging (MRI) in detecting and evaluating ischemic heart disease, conventional and enhanced CT were performed for 180 patients (150 with transmural infarction, 12 with subendocardial infarction, and 18 with angina pectoris). MRI examinations were performed for 38 patients (31 with transmural infarction, three with subendocardial infarction, and four with angina pectoris). With enhanced CT, two findings in the myocardium were direct evidence of myocardial infarction: 1) filling defects on the early scans, and 2) late enhancement of the myocardium on the delayed scans. The former were observed mainly at the sites of recent anterior myocardial infarction and the latter were seen in about half of the patients with recent and remote anterior myocardial infarctions. However, these findings were inadequately imaged in patients with inferoposterior infarction and subendocardial infarction. Among 137 patients with transmural infarction, enhanced CT revealed left ventricular aneurysms in 51 (37 %) and ventricular thrombi in 26 (19 %). ECG-gated MRI apparatus having a superconducting magnetic operating at 0.25 Tesla was used, and data for this study were collected using the single-slice spin echo technique. In eight of nine patients with acute myocardial infarction, gated MRI demonstrated the infarcted myocardium as regions of high signal intensity relative to that of the adjacent normal myocardium. Such a difference in MRI signal intensity was scarcely recognized in the chronic stage of myocardial infarction, but the indirect findings of infarction, such as regional wall thinning, wall motion disturbances, left ventricular aneurysms, and ventricular thrombi were easily detected using MRI. No characteristic finding was obtained by CT or MRI in patients with angina pectoris. (author)

Magnetic hysteresis effects in superconducting coplanar microwave resonators

Energy Technology Data Exchange (ETDEWEB)

Bothner, D.; Gaber, T.; Kemmler, M.; Gruenzweig, M.; Ferdinand, B.; Koelle, D.; Kleiner, R. [Universitaet Tuebingen (Germany); Wuensch, S.; Siegel, M. [Karlsruher Institut fuer Technologie (Germany); Mikheenko, P.; Johansen, T.H. [University of Oslo (Norway)

2013-07-01

We present experimental data regarding the impact of external magnetic fields on quality factor and resonance frequency of superconducting microwave resonators in a coplanar waveguide geometry. In particular we focus on the influence of magnetic history and show with the assistance of numerical calculations that the found hysteretic behaviour can be well understood with a highly inhomogeneous microwave current density in combination with established field penetration models for type-II superconducting thin films. Furthermore we have used magneto-optical imaging techniques to check the field distribution which we have assumed in our calculations. Finally, we demonstrate that and how the observed hysteretic behaviour can be used to optimize and tune the resonator performance for possible hybrid quantum sytems in magnetic fields.

Slotted cage resonator for high-field magnetic resonance imaging of rodents

Energy Technology Data Exchange (ETDEWEB)

Marrufo, O; Vasquez, F; Solis, S E; Rodriguez, A O, E-mail: arog@xanum.uam.mx [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico)

2011-04-20

A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

Magnetic resonance imaging features of brain and spinal cord injury in a fatal case of isopropanol intoxication

Directory of Open Access Journals (Sweden)

Mahajan PS

2014-03-01

Full Text Available Parag Suresh Mahajan,1 Joyal Jacob Mathew,2 Abhilash Pulincherry Jayaram,1 Vidya Chander Negi,1 Mohamed Milad Abu Hmaira21Department of Radiology, 2Department of Medicine, Al-Khor Hospital, Hamad Medical Corporation, Doha, QatarAbstract: A 60-year-old man presented with headache, dizziness, and disorientation one day after consumption of isopropanol along with ethanol. Computed tomography (CT of the brain performed immediately was unremarkable. The patient collapsed within the hospital 30 minutes after the CT scan was done, and remained comatose until death, showing no improvement with symptomatic treatment. Magnetic resonance imaging of the brain and spine done 6 days after admission revealed bilaterally symmetrical hyperintensities involving the cerebral and cerebellar cortex and white matter, basal ganglia, thalami, and brainstem on T2-weighted, fluid attenuated inversion recovery and diffusion weighted images; similar hyperintensities were seen involving the swollen and edematous cervical spinal cord and cerebellar tonsillar herniation compressing the proximal cervical cord. Petechial hemorrhages were also noted within the brainstem. These features are compatible with toxic injury to the brain and cervical spinal cord. To our knowledge, the magnetic resonance imaging features of brain and spinal cord injury and cerebellar tonsillar herniation, secondary to isopropanol intoxication have not been reported in the published literature before.Keywords: alcohol intoxication, computed tomography, isopropyl alcohol, ethyl alcohol, toxicity

Magnetic resonance tomography and computed tomography of the brain for diagnosing Wilson's disease

International Nuclear Information System (INIS)

Uhlenbrock, D.; Straube, A.; Beyer, H.K.; Leopold, H.C.

1985-01-01

The authors report on two woman patients with confirmed Wilson's desease (hepatolenticular degeneration) who had neurological deficits and showed typical changes evident from laboratory data. Both computed tomography and magnetic resonance tomography revealed degenerative changes in the basal ganglia, especially of the lenticular nucleus, MR showing these defects more clearly than CT. There was a noticeable symmetrical enhancement of signals in the lenticular nucleus which was particularly evident on the image basing on the T 2 (spin-spin relaxation time constant) values. MR could be superior to CT with regard to showing up pathological changes in the basal ganglia. The future indication of MR could be the establishment of an exact correlation between clinical signs and symptoms on the one hand, and morphological findings on the other. Over and above this, it should be explored to what extent MR can already detect degenerative changes in the brain in primarily hepatic types of the disease even without prior neurological examination. (orig.) [de

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

Science.gov (United States)

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.

Functional magnetic resonance imaging to determine hemispheric language dominance prior to carotid endarterectomy.

Science.gov (United States)

Smits, M; Wieberdink, R G; Bakker, S L M; Dippel, D W J

2011-04-01

We describe a left-handed patient with transient aphasia and bilateral carotid stenosis. Computed tomography (CT) arteriography showed a 90% stenosis of the right and 30% stenosis of the left internal carotid artery. Head CT and magnetic resonance imaging (MRI) of the brain showed no recent ischemic changes. As only the symptomatic side would require surgical intervention, and because hemispheric dominance for language in left-handed patients may be either left or right sided, a preoperative assessment of hemispheric dominance was required. We used functional MRI to determine hemispheric dominance for language and hence to establish the indication for carotid endarterectomy surgery. Functional MRI demonstrated right hemispheric dominance for language and right-sided carotid endarterectomy was performed. We propose that the clinical use of functional MRI as a noninvasive imaging technique for the assessment of hemispheric language dominance may be extended to the assessment of hemispheric language dominance prior to carotid endarterectomy. Copyright © 2010 by the American Society of Neuroimaging.

Diagnosis of magnetic resonance imaging (MRI) for blowout fracture. Three advantages of MRI

International Nuclear Information System (INIS)

Nishida, Yasuhiro; Aoki, Yoshiko; Hayashi, Osamu; Kimura, Makiko; Murata, Toyotaka; Ishida, Youichi; Iwami, Tatsuya; Kani, Kazutaka

1999-01-01

Magnetic resonance imaging (MRI) gives a much more detailed picture of the soft tissue than computerized tomography (CT). In blowout fracture cases, it is very easy to observe the incarcerated orbital tissue. We performed MRI in 19 blowout fracture cases. After evaluating the images, we found three advantages of MRI. The first is that even small herniation of the orbital contents can easily be detected because the orbital fatty tissue contrasts well around the other tissues in MRI. The second is that the incarcerated tissues can be clearly differentiated because a clear contrast between the orbital fatty tissue and the extraocular muscle can be seen in MRI. The third is that the running images of the incarcerated muscle belly can be observed because any necessary directional slies can be taken in MRI. These advantages are very important in the diagnosis of blowout fractures. MRI should be employed in blowout fracture cases in addition to CT. (author)

Hypothalamic-pituitary dwarfism: Comparison between MR imaging and CT findings

International Nuclear Information System (INIS)

Maghnie, M.; Larizza, D.; Severi, F.; Triulzi, F.; Scotti, G.; Beluffi, G.; Cecchini, A.

1990-01-01

Magnetic Resonance (MR) imaging was carried out on 33 patients with idiopathic growth hormone deficiency, in 22 of whom CT scan had been carried out previously. Twenty-one patients presented some complications at birth. Both MR and CT were positive in the evaluation of the sella. MR imaging exhibited a higher degree of accuracy than CT in the evaluation of pituitary gland, pituitary stalk and brain anomalies. (orig.)

Evaluation of magnetic resonance velocimetry for steady flow.

Science.gov (United States)

Ku, D N; Biancheri, C L; Pettigrew, R I; Peifer, J W; Markou, C P; Engels, H

1990-11-01

Whole body magnetic resonance (MR) imaging has recently become an important diagnostic tool for cardiovascular diseases. The technique of magnetic resonance phase velocity encoding allows the quantitative measurement of velocity for an arbitrary component direction. A study was initiated to determine the ability and accuracy of MR velocimetry to measure a wide range of flow conditions including flow separation, three-dimensional secondary flow, high velocity gradients, and turbulence. A steady flow system pumped water doped with manganese chloride through a variety of test sections. Images were produced using gradient echo sequences on test sections including a straight tube, a curved tube, a smoothly converging-diverging nozzle, and an orifice. Magnetic resonance measurements of laminar and turbulent flows were depicted as cross-sectional velocity profiles. MR velocity measurements revealed such flow behavior as spatially varying velocity, recirculation and secondary flows over a wide range of conditions. Comparisons made with published experimental laser Doppler anemometry measurements and theoretical calculations for similar flow conditions revealed excellent accuracy and precision levels. The successful measurement of velocity profiles for a variety of flow conditions and geometries indicate that magnetic resonance imaging is an accurate, non-contacting velocimeter.

Introduction to magnetic resonance and its application to dipole magnet testing

International Nuclear Information System (INIS)

Clark, W.G.

1992-01-01

An introduction to the features of magnetic resonance that are essential for understanding its application to testing accelerator dipole magnets is presented, including the accuracy that can be expected in field measurements and the factors that limit it. The use of an array of coils to measure the multipole moments of dipole magnets is discussed

Pleomorphic adenoma: Choice of radiographic imaging modality - Computed tomography or magnetic resonance imaging? Illustration through a case report

Directory of Open Access Journals (Sweden)

Shalu Rai

2013-01-01

Full Text Available Introduction: Pleomorphic adenoma (PA is the most common benign neoplasm of the major salivary glands arising primarily from the parotid gland. Computed tomography (CT is one of the primary imaging modalities used to assess the tumors of salivary glands. However, magnetic resonance imaging (MRI may provide additional information over CT. Case Report: We report the case of a 60-year-old male with a slowly enlarging, well-defined, round, painless, non-fixated, rubber-like swelling over the left ramus region below the ear, measuring about 4 × 4.5 cm, covering the lower border of the mandible near the angle. A provisional diagnosis of PA was given and CT and MRI were used to study the lesion. Discussion: Through this case, which was suspected to have undergone malignant transformation because of indistinct margins and focal hypodense areas on CT but was later confirmed to be a benign salivary gland tumor on MRI, we illustrate the role of CT and MRI as diagnostic aids in PA and emphasize on what should be the choice of imaging modality for parotid tumors.

CT and MRI-based door-needle-times for acute stroke patients a quasi-randomized clinical trial

DEFF Research Database (Denmark)

Hansen, Christine Krarup; Christensen, Anders; Rodgers, Helen

2017-01-01

OBJECTIVES: Door-Needle-times (DNT) of 20min are feasible when Computer Tomography (CT) is used for first-line brain-imaging to assess stroke-patients' eligibility for intravenous-tissue-Plasminogen-Activator (iv-tPA), but the more time-consuming Magnetic Resonance Imaging (MRI)-based-evaluation ......OBJECTIVES: Door-Needle-times (DNT) of 20min are feasible when Computer Tomography (CT) is used for first-line brain-imaging to assess stroke-patients' eligibility for intravenous-tissue-Plasminogen-Activator (iv-tPA), but the more time-consuming Magnetic Resonance Imaging (MRI...

Infected aortic aneurysm presenting as prevertebral abscess in magnetic resonance imaging: A case report

International Nuclear Information System (INIS)

Yu, Jung Re; Ko, Seong Joo; Heo, Sang Taek; Kim, Jin Seok; Kim, Seung Hyoung

2013-01-01

The differential diagnosis of mass-like lesions around the aorta includes saccular pseudoaneurysms and abscesses. A 69-year-old female was admitted with multiple abscesses and fluid collections in several muscles and joints. Methicillin susceptible Staphylococcus aureus was isolated from her blood and pus. Even though she was treated with repeated operations and appropriate antibiotics, her conditions worsened with persistent fever and newly developed abscesses at other sites. Serial enhanced computed tomography (CT) revealed a newly developed saccular abdominal aortic aneurysm in the retroaortic space at the celiac axis level. However, the infected aortic aneurysm mimicked a prevertebral abscess on enhanced spinal magnetic resonance imaging (MRI) due to its heterogeneous signal intensity caused by intraaneurysmal turbulent blood flow. We report to alert the pitfall in the diagnosis of saccular aortic aneurysm using spinal MRI and the importance of serial enhanced CT study in highly suspicious patients.

Computed tomographic, magnetic resonance imaging, and cross-sectional anatomic features of the manus in a normal American black bear (Ursus americanus).

Science.gov (United States)

Ober, C P; Freeman, L E

2010-06-01

The purpose of this study was to provide a detailed description of cross-sectional anatomic structures of the manus of a black bear cadaver and correlate anatomic findings with corresponding features in computed tomographic (CT) and magnetic resonance (MR) images. CT, MR imaging, and transverse sectioning were performed on the thoracic limb of a cadaver female black bear which had no evidence of lameness or thoracic limb abnormality prior to death. Features in CT and MR images corresponding to clinically important anatomic structures in anatomic sections were identified. Most of the structures identified in transverse anatomic sections were also identified using CT and MR imaging. Bones, muscles and tendons were generally easily identified with both imaging modalities, although divisions between adjacent muscles were rarely visible with CT and only visible sometimes with MR imaging. Vascular structures could not be identified with either imaging modality.

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available ... MRI) exam. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, ...

Contrast-enhanced magnetic resonance imaging of tumours of the central nervous systems: a clinical review

International Nuclear Information System (INIS)

Graif, M.; Steiner, R.E.

1986-01-01

The clinical application of the intravascular paramagnetic contrast agent gadolinium-DTPA for magnetic resonance imaging (MRI) imaging of tumours of the central nervous system (CNS) has been assessed over the past 3 years. Various patterns of contrast enhancement were observed, and situations in MRI where the administration of contrast medium may be useful have been defined. These include lesions which are isointense with normal brain matter, the separation of tumour from surrounding oedema, evaluation of the degree of blood-brain barrier breakdown, delineation of tumours obscured by overlying calcification on computed tomography (CT) and in the investigation of lesions in anatomical areas where CT has known limitations (brain, stem, cervical spine). Changes in relaxation times in normal and abnormal tissues following contrast medium, toxicity and dosage of gadolinium-DTPA, and MRI pulse sequence techniques are reviewed. (author)

Imaging by magnetic resonance

International Nuclear Information System (INIS)

Duroure, J.F.; Serpolay, H.; Vallens, D.

1995-01-01

Here are described the advanced technology for nuclear magnetic resonance imaging: reduction of acquisition times, and rebuilding times, images quality improvement. The tendency is to open the machines at low and middle field, on a market being at 10% of NMR I sales, with economical, scientifical and ergonomic reasons broadly developed by constructors

Suppressing magnetic island growth by resonant magnetic perturbation

Science.gov (United States)

Yu, Q.; Günter, S.; Lackner, K.

2018-05-01

The effect of externally applied resonant magnetic perturbations (RMPs) on the growth of magnetic islands is investigated based on two-fluid equations. It is found that if the local bi-normal electron fluid velocity at the resonant surface is sufficiently large, static RMPs of the same helicity and of moderate amplitude can suppress the growth of magnetic islands in high-temperature plasmas. These islands will otherwise grow, driven by an unfavorable plasma current density profile and bootstrap current perturbation. These results indicate that the error field can stabilize island growth, if the error field amplitude is not too large and the local bi-normal electron fluid velocity is not too low. They also indicate that applied rotating RMPs with an appropriate frequency can be utilized to suppress island growth in high-temperature plasmas, even for a low bi-normal electron fluid velocity. A significant change in the local equilibrium plasma current density gradient by small amplitude RMPs is found for realistic plasma parameters, which are important for the island stability and are expected to be more important for fusion reactors with low plasma resistivity.

Magnetic moment oscillation in ammonium perchlorate in a DC SQUID-based magnetic resonance experiment

International Nuclear Information System (INIS)

Montero, V.; Cernicchiaro, G.

2008-01-01

In this work we describe experimental results in which a DC SQUID (superconducting quantum interference device) is used as free induction decay detector. Measurements of a solid ammonium perchlorate (NH 4 ClO 4 ) sample were performed, in zero field, at 4.2 K. Unexpected magnetic moment oscillations were detected at 1.5 kHz. The computation of the magnetic fields suggests that the proton nuclear magnetic resonance may explain the measured resonance, considering reorientation of the ammonium group by quantum tunneling of protons and a magnetic proton dipole-dipole intermolecular interaction model

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... are the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging ( ... brain) in routine clinical practice. top of page What are some common uses of the procedure? MR ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... necessary in trauma situations. Although there is no reason to believe that magnetic resonance imaging harms the ...

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available ... it is useful to bring that to the attention of the technologist or scheduler before the exam. ... patient for magnetic resonance imaging (MRI) exam. View full size with caption Pediatric Content Some imaging tests ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... it is useful to bring that to the attention of the scheduler before the exam and bring ... Image Gallery Magnetic Resonance Imaging (MRI) procedure View full size with caption Pediatric Content Some imaging tests ...

Simulation of a resonant-type ring magnet power supply with multiple resonant cells and energy storage chokes

International Nuclear Information System (INIS)

Kim, J.M.S.; Blackmore, E.W.; Reiniger, K.W.

1992-01-01

For the TRIUMF KAON Factory Booster Ring, a resonant-type magnet power supply has been proposed for the dipole magnet excitation. The Booster Ring magnet power supply system based on resonant circuits, coupled with distributed energy make-up networks, is a complex system, sensitive to many system parameters. When multiple resonant cells, each with its own energy make-up network, are connected in a ring, it is very difficult to derive closed-form solutions to determine the operating conditions of the power supply system. A meaningful way to understand and analyze such a complex system is to use a simulation tool. This paper presents the analysis of operating conditions of the resonant-type ring magnet power supply with multiple resonant cells, using the circuit simulation tool, SPICE. The focus of the study is on the effect of circuit parameter variations in energy storage chokes

Soft X-ray resonant scattering from magnetic heterostructures

International Nuclear Information System (INIS)

Grabis, J.

2005-01-01

Heterogenous magnetic multilayers are of great interest both because of their relevance for technological applications and since they provide model systems to understand magnetic behavior and interactions. Soft x-ray resonant magnetic scattering (XRMS) allows to determine element-specific and depth-resolving information of the local magnetic order of such systems. Within the framework of the present thesis the diffractometer ALICE for soft XRMS has been constructed. XRMS measurements of two different physical systems are presented in this thesis: The antiferromagnetic and ferromagnetic order in interlayer exchange-coupled Fe/Cr(001) superlattices are studied as a function of the applied field by measuring the reflected intensity at different positions in reciprocal space. Thin films and multilayers of the Heusler compound Co 2 MnGe are studied by means of soft x-ray absorption spectroscopy, magnetic circular dichroism and resonant magnetic scattering

Automatic injectors in magnetic resonance imaging and computed tomography: pilot study on hygienic aspects

International Nuclear Information System (INIS)

Buerke, B.; Fischbach, R.; Heindel, W.; Tombach, B.; Sonntag, A.K.

2004-01-01

Purpose: To evaluate hygienic conditions using automatic injectors in magnetic resonance imaging (MRI) and computed tomography (CT) during clinical routine. Materials and methods: The surfaces of medical devices (e.g., control console) and the palms of the technical and medical staff were microbiologically analyzed by taking imprints before and after hygienic education. In addition, the injector syringes for contrast medium (CM) and saline were checked for microbiological contamination following multiple (MRI: 14h; CT 8h) and single use. Furthermore, the potential of retrograde contamination from the patient along the tube was analyzed. Results: A bacterial contamination with typical dermal bacteria was documented for the surfaces of the medical devices, the palms of the technical and medical staff, and the injection syringes following multiple use (MRI: 10/10 CM syringes, 6/10 saline syringes; CT: 8/10 CM syringes, 5/10 saline syringes). Correct hand disinfection in combination with single use of syringes avoided bacterial colonization. Retrograde bacterial contamination from the patient was not observed. Conclusion: Regular hygienic teaching sessions for technical and medical staff in MRI and CT departments using automatic injectors should be mandatory. Furthermore, the multiple use of syringes should be avoided until investigations addressing the potential of bacterial contamination are performed. (orig.)

Nuclear magnetic resonance

International Nuclear Information System (INIS)

Cremin, B.J.

1981-01-01

Recent advances in diagnostic imaging, have been the medical application of nuclear magnetic resonance (NMR). It's been used to study the structure of various compounds in chemistry and physics, and in the mid-1970 to produce images of rabbits and eventually of the human hand and head. The images are produced by making use of the nuclear magnetization of the hydrogen ion, or proton, that is present in biological material to record the density distribution of protons in cellular water and lipids. An exploration of the end-results of complicated free induction decay signals, that have been digitized and frequency-analysed by mathematical computerized techniques to produce an image of tissue density, is given. At present NMR produces images comparable to those of early computed tomography

Artifacts Affecting Musculoskeletal Magnetic Resonance Imaging: Their Origins and Solutions.

Science.gov (United States)

Roth, Eira; Hoff, Michael; Richardson, Michael L; Ha, Alice S; Porrino, Jack

2016-01-01

Among articles within the radiology literature, few present the manifestations of magnetic resonance imaging artifacts in a clinically oriented manner. Recognizing such artifacts is imperative given the increasing clinical use of magnetic resonance imaging and the emphasis by the American Board of Radiology on practical physics applications. The purpose of this article is to present magnetic resonance physics principles visually and conceptually in the context of common musculoskeletal radiology artifacts and their solutions, described using nonmathematical explanations. Copyright © 2016 Elsevier Inc. All rights reserved.

Acute anterior myocardial infarction seen on conventional iodine-contrast CT

Directory of Open Access Journals (Sweden)

Christian Hagdrup, MD

2017-09-01

Full Text Available Diagnosis of acute myocardial infarction (AMI is based on clinical symptoms of chest pain and dyspnea in combination with electrocardiographic changes and a raise in myocardial-specific biomarkers. Imaging is by echocardiography and magnetic resonance. The preferred technique for identification of previous myocardial infarction (MI is magnetic resonance imaging with late gadolinium technique, but in the acute patient echocardiography is applied. In selected cases, important information can be obtained from other imaging modalities. We describe a case of a patient first suspected of an abdominal catastrophe in whom acute MI was diagnosed from a computerized tomography (CT scan with iodine contrast. Our case together with a few other cases reported in the literature demonstrate that contrast enhancement of the myocardium can be important to follow in the acute patient because the CT scans sometimes give a unique opportunity to recognize findings consistent with MI even though the CT scan was performed for another reason.