Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

22 results found
Article

Ammonia (N-13)

13NH3 is a PET tracer used for studies of myocardial perfusion imaging. It is produced in a cyclotron by proton irradiation of the enriched water of the oxygen-16. Ammonia (N-13) is administered intravenously, at a dose of 10-20 mCi (370-740 Mbq) in adults; its physical half-life is 10 minutes. ...
Article

Calcium mass score

The calcium mass score was introduced to determine the absolute mass of coronary artery calcium with the help of a cardiac calibration phantom and the use of correction factors 1,4. The method itself comprises the integration of signal above a given threshold 3. Even though, higher sensitivity ...
Article

Cardiac gating (MRI)

Cardiac gating or cardiac triggering refers to the gain of information about specific time points and its use for image acquisition during the cardiac cycle. Technique Cardiac synchronization can be achieved by the ECG signal or alternatively with a peripheral pulse transducer. The following t...
Article

Cardiac ischemia protocol (MRI)

The cardiac MRI ischemia or stress protocol encompasses a set of different MRI sequences for the assessment of myocardial ischemia. Note: This article aims to frame a general concept of a cardiac MRI protocol in the setting of vasodilator stress perfusion testing. Protocol specifics will vary ...
Article

Cardiac MRI

Cardiac MRI consists of using MRI to study heart anatomy, physiology, and pathology. Advantages In comparison to other techniques, cardiac MRI offers: improved soft tissue definition protocol can be tailored to likely differential diagnoses a large number of sequences are available dynamic...
Article

Coronary MR angiography

Coronary MR angiography (coronary MRA) is a developing approach to imaging the coronary arteries. Advantages of coronary MRA include avoidance of the intravenous iodinated contrast and ionizing radiation used in coronary CT angiography and conventional angiography. A disadvantage of coronary M...
Article

Diastolic pseudogating

Diastolic pseudogating appears as periodic bright and dark signal in arteries such as the aorta as one progresses through a series of images. Synchronization of the cardiac cycle and the pulse sequence results in high signal in the artery during diastole when blood is relatively stationary and l...
Article

Double oblique multiplanar reconstruction

Double oblique is a type of multiplanar reconstruction used in cardiac cross-sectional imaging. It is useful for an accurate assessment of the ascending aorta and aortic annulus, and is particularly useful for pre- and post-procedure evaluation of a transcatheter aortic valve replacement (TAVR)....
Article

D-SPECT

D-SPECT represents the next step in the evolution of SPECT technology and is based on a unique acquisition geometry. It has nine arrays of cadmium zinc telluride (CZT) detectors, each of which rotates around its central axis with programmable angular rotation 1. The detectors are very compact al...
Article

Extracellular volume (ECV) - myocardium

Extracellular volume (ECV) refers to the space or volume of a tissue, which is not occupied by cells. Apart from the usual extracellular space, which surrounds the cells of a specific tissue it also includes the intracapillary plasma volume 1,2. It measures the space, which is occupied by the ex...
Article

Late gadolinium enhancement

Late gadolinium enhancement is a technique used in cardiac magnetic resonance imaging for cardiac tissue characterization, in particular, the assessment of regional scar formation and myocardial fibrosis 1-5. Terminology Late gadolinium enhancement is also known under the terms ‘late enhanceme...
Article

MR feature tracking

MR feature tracking refers to an MRI based post-processing method, used on normal cine SFFP sequences for the analysis of myocardial deformation and the determination of myocardial strain parameters. Methodology MRI feature tracking is a two-dimensional software algorithm applied on standard c...
Article

MR tagging

Cardiac MR tagging or myocardial tagging refers to a MRI based acquisition method designed for myocardial deformation analysis. Methodology The method exploits tissue magnetization as a tissue property. A local magnetic saturation grid of dark lined tissue markers known as tags are induced ont...
Article

Myocardial mapping

Myocardial mapping or parametric mapping of the heart is one of various magnetic resonance imaging techniques, which has evolved and been increasingly used in the last decade for non-invasive tissue characterization of the myocardium 1-5. Unlike normal T1-, T2- or T2*- images, parametric mapping...
Article

Speckle tracking echocardiography

Speckle tracking echocardiography describes the semi-automated analysis of grey scale (B-mode) echocardiographic studies in which the spatial translocation of derived functional units (speckles) allows quantitative analysis of myocardial function. Speckle tracking constitutes a subset of deform...
Article

Spectral Doppler (ultrasound)

Utilizing automated Fourier analysis to convert returning sound waves into a series of individual frequencies, spectral Doppler refers to ultrasound modalities which yield graphical representations of flow velocity over time.  Terminology The frequency of the sound waves returned to an ultraso...
Article

T1 mapping - myocardium

T1 mapping is a magnetic resonance imaging technique used to calculate the T1 time of a certain tissue and display them voxel-vice on a parametric map. It has been used for myocardial tissue characterization 1-6 and has been investigated for other tissues 5. T1 is the spin-lattice or longitudin...
Article

T2 mapping - myocardium

T2 mapping is a magnetic resonance imaging technique used to calculate the T2 times of a certain tissue and display them voxel-vice on a parametric map. It has been used for tissue characterization of the myocardium 1-5 and has been investigated for cartilage 6,7 and other tissues 4. The T2 tim...
Article

T2* mapping - myocardium

T2* mapping is a magnetic resonance imaging technique used to calculate the T2* time of tissue and display them voxel-vice on a parametric map. It is used for myocardial tissue characterization 1-4 and has been investigated for other tissues 5,6. Methodology T2* mapping is usually based on gra...
Article

Thallium-201 scintigraphy

Thallium-201 (Th-201) is a radiopharmaceutical used for scintigraphy, primarily of the myocardium. The element thallium is treated by the body as an analog of potassium; it is produced in a cyclotron by bombarding thallium-203 with protons. Characteristics thallium is a monovalent cation usua...
Article

Tissue Doppler imaging (echocardiography)

A variant of pulsed wave Doppler, tissue Doppler imaging (TDI) is a modality in echocardiography that allows measurement of the velocity of myocardial movement throughout the cardiac cycle. Physics Color flow, pulsed wave, and continuous wave Doppler are designed to analyze the Doppler shifts ...
Article

Velocity encoding

Velocity encoding or Venc is referred to as an operator-controlled parameter for the determination of the maximum velocity within a velocity encoded phase contrast imaging study. Usage Velocity-encoding (Venc) gradients are used to generate a phase shift in magnetic resonance phase contrast im...

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