방사선사나라 Radiographer Nara

(English) Type of coil 1. Shim coil Various adjustments are made to the MRI device to obtain uniformity, which is called shimming. The shim coil is a coil with a current flowing in a complex structure and it is used in an active method to make the static magnetic field more uniform. 2. Gradient coil It is installed in the shim coil inside the magnet of the static magnetic field along the x, y, a..

(English) Resistive magnet? 1. Iron-core resistive magnet type (H type) It is also called H type because it is made of an electromagnet by winding a coil of copper or aluminum around the center of iron. Relatively strong magnets can be made with little power, and unlike air-core resistive magnet type and superconducting magnet, magnetic flux is completely sealed. For this reason, devices for hum..

(English) What is superconductivity? It refers to the state in which the electrical resistance becomes zero. Since there is no electric resistance, there is no electric loss due to heat generation, so a permanent magnetic field can be produced. However, this superconducting phenomenon occurs at an extremely low temperature close to the absolute temperature. Therefore, in order to cool the superc..

(English) 2D TOF? (Compared to 3D TOF) Advantages - It is sensitive to slow blood flow and short image acquisition time. Disadvantages - Blood vessels running parallel to the image slice are not visible, and the image acquisition time is long and sensitive to the patient's movement. 3D TOF? (Compared to 2D TOF) Advantages - Spatial resolution and SNR is good and it is sensitive to medium or rapi..

(English) CE MRA (Contrast Enhanced Magnetic Resonance Angiography)? By using short TR and TE, heavily T1WI are acquired. The surrounding tissues are highly saturated, producing very small signals, while the blood is relatively less saturated by contrast agents, so images of good contrast can be obtained. It is important to inject the contrast agent through a vein in order to obtain an appropria..

(English) PC (Phase Contrast) technique? A bipolar gradient is required as a method of using a phase shift phenomenon in which spin is caused by a gradient magnetic field. The PC technique is useful for the detection of low-velocity blood vessels by removing the background (useful for intravenous imaging), and can provide information about the flow force of the imaged blood flows associated with..

(English)3D TOF MRA? This is a method of acquiring a 3D image by performing z-axis encoding in the slice selection direction in addition to the frequency direction and the phase direction. Like 2D TOF MRA, it is a method that uses the flow related signal enhancement phenomenon of the inflowing blood flow and is the most used method to view the vessels of the head.Compared to 2D TOF MRA, SNR is b..

(English) 2D TOF MRA? It is basically a blood flow compensation gradient echo imaging technique. The stationary spin in tissue in the imaging slice is saturated by the RF pulse, but the blood flow entering the imaging slice is completely magnetized and shows high signal intensity. If a saturation (presaturation) pulse is applied above or below the selected slice, all signals of blood flow coming..

(English) TOF (Time Of Flight)? It is commonly used in blood flow compensation gradient echo images by using the flow related signal enhancement effect. Basically, spin is readout after a certain period of time after being selected as a single RF. If the position of the spin is changed between these time intervals, TOF effect appears and the blood flow is seen as a high signal intensity by the R..

(English) MRA(Magnetic Resonance Angiography)? A field of MRI that provides non-invasively morphological information of blood vessels By maximizing the signal intensity of the blood flow and minimizing the signal from the stationary material, the images obtained by maximizing the contrast among the protons are obtained by using the MIP(Maximum Intensity Projection) method. MRA is divided into co..