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Result : Searchterm 'Ultrasound' found in 0 term [] and 27 definitions []
| previous 6 - 10 (of 27) nextResult Pages : [1 2 3 4 5 6] | | | | Searchterm 'Ultrasound' was also found in the following services: | | | | |
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(MR mammography) Magnetic resonance imaging of the breast is particularly useful in evaluation of newly diagnosed breast cancer, in women whose breast tissue is mammographically very dense and for screening in women with a high lifetime risk of breast cancer because of their family history or genetic disposition.
Breast MRI can be performed on all standard whole body magnets at a field strength of 0.5 T - 1.5 Tesla. Powerful gradient strengths over 15 mT/m will help to improve the balance between spatial resolution, scanning speed, and volume coverage. The use of a dedicated bilateral breast coil is obligatory.
Malignant lesions release angiogenic factors that increase local vessel density and vessel permeability. Breast cancer is detectable due to the strong enhancement in dynamic breast imaging that peaks early (about 1-2 min.) after contrast medium injection. If breast cancer is suspected, a breast biopsy may be necessary to secure the diagnosis. See also Magnetic Resonance Imaging MRI, Biopsy and MR Guided Interventions.
Requirements in breast MRI procedures:
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Both breasts must be measured without gaps.
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For the best possible detection of enhancement fat signal should be eliminated either by image subtraction or by
spectrally selective fat saturation.
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Thin slices are necessary to assure absence of partial
volume effects.
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Imaging should be performed with a spatial
resolution in plane less than 1 mm.
For Ultrasound Imaging (USI) see Breast Ultrasound at Medical-Ultrasound-Imaging.com.
See also the related poll result: ' MRI will have replaced 50% of x-ray exams by' | | | | | | | | | | | | | | | | Further Reading: | | Basics:
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Technology advances in breast cancer screenings lead to early diagnosis Friday, 6 October 2023 by ksltv.com | | |
Are synthetic contrast-enhanced breast MRI images as good as the real thing? Friday, 18 November 2022 by healthimaging.com | | |
Abbreviated breast MRI protocols not as cost-effective as promised, new study shows Wednesday, 20 July 2022 by healthimaging.com | | |
Deep learning poised to improve breast cancer imaging Thursday, 24 February 2022 by www.eurekalert.org | | |
Pre-Operative Breast MRI Can Help Identify Patients Likely to Experience Nipple-Sparing Mastectomy Risks Wednesday, 7 April 2021 by www.diagnosticimaging.com | | |
Breast cancer screening recalls: simple MRI measurement could avoid 30% of biopsies Monday, 1 March 2021 by www.eurekalert.org | | |
A Comparison of Methods for High-Spatial-Resolution Diffusion-weighted Imaging in Breast MRI Tuesday, 25 August 2020 by pubs.rsna.org | | |
Pre-Operative Breast MRI Diagnoses More Cancers in Women with DCIS Thursday, 9 July 2020 by www.diagnosticimaging.com | | |
Breast MRI and tumour biology predict axillary lymph node response to neoadjuvant chemotherapy for breast cancer Thursday, 26 December 2019 by cancerimagingjournal.biomedcentral.com | | |
Breast MRI Coding Gets an Overhaul in 2019 Wednesday, 9 January 2019 by www.aapc.com | | |
How accurate are volumetric software programs when compared to breast MRI? Thursday, 27 July 2017 by www.radiologybusiness.com | | |
Additional Breast Cancer Tumors Found on MRI After Mammography May Be Larger, More Aggressive Wednesday, 9 December 2015 by www.oncologynurseadvisor.com | | |
Preoperative MRI May Overdiagnose Contralateral Breast Cancer Wednesday, 2 December 2015 by www.cancertherapyadvisor.com | | |
BI-RADS and breast MRI useful in predicting malignancy Wednesday, 30 May 2012 by www.oncologynurseadvisor.com |
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In the last years, cardiac MRI techniques have progressively improved. No other noninvasive imaging modality provides the same degree of contrast and temporal resolution for the assessment of cardiovascular anatomy and pathology. Contraindications MRI are the same as for other magnetic resonance techniques.
The primary advantage of MRI is extremely high contrast resolution between different tissue types, including blood. Moreover, MRI is a true 3 dimensional imaging modality and images can be obtained in any oblique plane along the true cardiac axes while preserving high temporal and spatial resolution with precise demonstration of cardiac anatomy without the administration of contrast media.
Due to these properties, MRI can precisely characterize cardiac function and quantify cavity volumes, ejection fraction, and left ventricular mass. In addition, cardiac MRI has the ability to quantify flow (see flow quantification), including bulk flow in vessels, pressure gradients across stenosis, regurgitant fractions and shunt fractions. Valve morphology and area can be determined and the severity of stenosis quantified. In certain disease states, such as myocardial infarction, the contrast resolution of MRI is further improved by the addition of extrinsic contrast agents (see myocardial late enhancement).
A dedicated cardiac coil, and a field strength higher than 1 Tesla is recommended to have sufficient signal. Cardiac MRI acquires ECG gating. Cardiac gating (ECGs) obtained within the MRI scanner, can be degraded by the superimposed electrical potential of flowing blood in the magnetic field. Therefore, excellent contact between the skin and ECG leads is necessary. For male patients, the skin at the lead sites can be shaved. A good cooperation of the patient is necessary because breath holding at the end of expiration is practiced during the most sequences.
See also Displacement Encoding with Stimulated Echoes.
For Ultrasound Imaging (USI) see Cardiac Ultrasound at Medical-Ultrasound-Imaging.com.
See also the related poll results: ' In 2010 your scanner will probably work with a field strength of' and ' MRI will have replaced 50% of x-ray exams by' | | | | | | • View the DATABASE results for 'Cardiac MRI' (15).
| | | • View the NEWS results for 'Cardiac MRI' (15).
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MRI technology visualizes heart metabolism in real time Friday, 18 November 2022 by medicalxpress.com | | |
Even early forms of liver disease affect heart health, Cedars-Sinai study finds Thursday, 8 December 2022 by www.eurekalert.org | | |
MRI sheds light on COVID vaccine-associated heart muscle injury Tuesday, 15 February 2022 by www.sciencedaily.com | | |
Radiologists must master cardiac CT, MRI to keep pace with demand: The heart is not a magical organ Monday, 1 March 2021 by www.radiologybusiness.com | | |
Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) in the heart (myocardium) Sunday, 30 August 2020 by github.com | | |
Non-invasive diagnostic procedures for suspected CHD: Search reveals informative evidence Wednesday, 8 July 2020 by medicalxpress.co | | |
Cardiac MRI Becoming More Widely Available Thanks to AI and Reduced Exam Times Wednesday, 19 February 2020 by www.dicardiology.com | | |
Controlling patient's breathing makes cardiac MRI more accurate Friday, 13 May 2016 by www.upi.com | | |
Precise visualization of myocardial injury: World's first patient-based cardiac MRI study using 7T MRI Wednesday, 10 February 2016 by medicalxpress.com | | |
New technique could allow for safer, more accurate heart scans Thursday, 10 December 2015 by www.gizmag.com |
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| | | | | | • View the DATABASE results for 'Contrast Enhanced MR Venography' (3).
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| | | Searchterm 'Ultrasound' was also found in the following services: | | | | |
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Contrast enhanced MRI is a commonly used procedure in magnetic resonance imaging. The need to more accurately characterize different types of lesions and to detect all malignant lesions is the main reason for the use of intravenous contrast agents.
Some methods are available to improve the contrast of different tissues. The focus of dynamic contrast enhanced MRI (DCE-MRI) is on contrast kinetics with demands for spatial resolution dependent on the application. DCE- MR imaging is used for diagnosis of cancer (see also liver imaging, abdominal imaging, breast MRI, dynamic scanning) as well as for diagnosis of cardiac infarction (see perfusion imaging, cardiac MRI). Quantitative DCE-MRI requires special data acquisition techniques and analysis software.
Contrast enhanced magnetic resonance angiography (CE-MRA) allows the visualization of vessels and the temporal resolution provides a separation of arteries and veins. These methods share the need for acquisition methods with high temporal and spatial resolution.
Double contrast administration (combined contrast enhanced (CCE) MRI) uses two contrast agents with complementary mechanisms e.g., superparamagnetic iron oxide to darken the background liver and gadolinium to brighten the vessels. A variety of different categories of contrast agents are currently available for clinical use.
Reasons for the use of contrast agents in MRI scans are:
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Relaxation characteristics of normal and pathologic tissues are not always different enough to produce obvious differences in signal intensity.
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Pathology that is sometimes occult on unenhanced images becomes obvious in the presence of contrast.
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Enhancement significantly increases MRI sensitivity.
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In addition to improving delineation between normal and abnormal tissues, the pattern of contrast enhancement can improve diagnostic specificity by facilitating characterization of the lesion(s) in question.
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Contrast can yield physiologic and functional information in addition to lesion delineation.
Common Indications:
Brain MRI : Preoperative/pretreatment evaluation and postoperative evaluation of brain tumor therapy, CNS infections, noninfectious inflammatory disease and meningeal disease.
Spine MRI : Infection/inflammatory disease, primary tumors, drop metastases, initial evaluation of syrinx, postoperative evaluation of the lumbar spine: disk vs. scar.
Breast MRI : Detection of breast cancer in case of dense breasts, implants, malignant lymph nodes, or scarring after treatment for breast cancer, diagnosis of a suspicious breast lesion in order to avoid biopsy.
For Ultrasound Imaging (USI) see Contrast Enhanced Ultrasound at Medical-Ultrasound-Imaging.com.
See also Blood Pool Agents, Myocardial Late Enhancement, Cardiovascular Imaging, Contrast Enhanced MR Venography, Contrast Resolution, Dynamic Scanning, Lung Imaging, Hepatobiliary Contrast Agents, Contrast Medium and MRI Guided Biopsy. | | | | | | | | | | | • View the DATABASE results for 'Contrast Enhanced MRI' (14).
| | | • View the NEWS results for 'Contrast Enhanced MRI' (8).
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FDA Approves Gadopiclenol for Contrast-Enhanced Magnetic Resonance Imaging Tuesday, 27 September 2022 by www.pharmacytimes.com | | |
Effect of gadolinium-based contrast agent on breast diffusion-tensor imaging Thursday, 6 August 2020 by www.eurekalert.org | | |
Artificial Intelligence Processes Provide Solutions to Gadolinium Retention Concerns Thursday, 30 January 2020 by www.itnonline.com | | |
Accuracy of Unenhanced MRI in the Detection of New Brain Lesions in Multiple Sclerosis Tuesday, 12 March 2019 by pubs.rsna.org | | |
The Effects of Breathing Motion on DCE-MRI Images: Phantom Studies Simulating Respiratory Motion to Compare CAIPIRINHA-VIBE, Radial-VIBE, and Conventional VIBE Tuesday, 7 February 2017 by www.kjronline.org | | |
Novel Imaging Technique Improves Prostate Cancer Detection Tuesday, 6 January 2015 by health.ucsd.edu | | |
New oxygen-enhanced MRI scan 'helps identify most dangerous tumours' Thursday, 10 December 2015 by www.dailymail.co.uk | | |
All-organic MRI Contrast Agent Tested In Mice Monday, 24 September 2012 by cen.acs.org | | |
A groundbreaking new graphene-based MRI contrast agent Friday, 8 June 2012 by www.nanowerk.com |
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Magnetic resonance imaging ( MRI) is based on the magnetic resonance phenomenon, and is used for medical diagnostic imaging since ca. 1977 (see also MRI History).
The first developed MRI devices were constructed as long narrow tunnels. In the meantime the magnets became shorter and wider. In addition to this short bore magnet design, open MRI machines were created. MRI machines with open design have commonly either horizontal or vertical opposite installed magnets and obtain more space and air around the patient during the MRI test.
The basic hardware components of all MRI systems are the magnet, producing a stable and very intense magnetic field, the gradient coils, creating a variable field and radio frequency (RF) coils which are used to transmit energy and to encode spatial positioning. A computer controls the MRI scanning operation and processes the information.
The range of used field strengths for medical imaging is from 0.15 to 3 T. The open MRI magnets have usually field strength in the range 0.2 Tesla to 0.35 Tesla. The higher field MRI devices are commonly solenoid with short bore superconducting magnets, which provide homogeneous fields of high stability.
There are this different types of magnets:
The majority of superconductive magnets are based on niobium-titanium (NbTi) alloys, which are very reliable and require extremely uniform fields and extreme stability over time, but require a liquid helium cryogenic system to keep the conductors at approximately 4.2 Kelvin (-268.8° Celsius). To maintain this temperature the magnet is enclosed and cooled by a cryogen containing liquid helium (sometimes also nitrogen).
The gradient coils are required to produce a linear variation in field along one direction, and to have high efficiency, low inductance and low resistance, in order to minimize the current requirements and heat deposition. A Maxwell coil usually produces linear variation in field along the z-axis; in the other two axes it is best done using a saddle coil, such as the Golay coil.
The radio frequency coils used to excite the nuclei fall into two main categories; surface coils and volume coils.
The essential element for spatial encoding, the gradient coil sub-system of the MRI scanner is responsible for the encoding of specialized contrast such as flow information, diffusion information, and modulation of magnetization for spatial tagging.
An analog to digital converter turns the nuclear magnetic resonance signal to a digital signal. The digital signal is then sent to an image processor for Fourier transformation and the image of the MRI scan is displayed on a monitor.
For Ultrasound Imaging (USI) see Ultrasound Machine at Medical-Ultrasound-Imaging.com.
See also the related poll results: ' In 2010 your scanner will probably work with a field strength of' and ' Most outages of your scanning system are caused by failure of' | | | | | | | | | • View the DATABASE results for 'Device' (141).
| | | • View the NEWS results for 'Device' (29).
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small-steps-can-yield-big-energy-savings-and-cut-emissions-mris Thursday, 27 April 2023 by www.itnonline.com | | |
Portable MRI can detect brain abnormalities at bedside Tuesday, 8 September 2020 by news.yale.edu | | |
Point-of-Care MRI Secures FDA 510(k) Clearance Thursday, 30 April 2020 by www.diagnosticimaging.com | | |
World's First Portable MRI Cleared by FDA Monday, 17 February 2020 by www.medgadget.com | | |
Low Power MRI Helps Image Lungs, Brings Costs Down Thursday, 10 October 2019 by www.medgadget.com | | |
Cheap, portable scanners could transform brain imaging. But how will scientists deliver the data? Tuesday, 16 April 2019 by www.sciencemag.org | | |
The world's strongest MRI machines are pushing human imaging to new limits Wednesday, 31 October 2018 by www.nature.com | | |
Kyoto University and Canon reduce cost of MRI scanner to one tenth Monday, 11 January 2016 by www.electronicsweekly.com | | |
A transportable MRI machine to speed up the diagnosis and treatment of stroke patients Wednesday, 22 April 2015 by medicalxpress.com | | |
Portable 'battlefield MRI' comes out of the lab Thursday, 30 April 2015 by physicsworld.com | | |
Chemists develop MRI technique for peeking inside battery-like devices Friday, 1 August 2014 by www.eurekalert.org | | |
New devices doubles down to detect and map brain signals Monday, 23 July 2012 by scienceblog.com |
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