방사선사나라 Radiographer Nara

(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) 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) 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..

(영어/영문/English) The concept of 3D in MR imaging refers to a method of acquiring images. In the 3-dimension method, RF pulses are applied to the entire volume to be imaged to determine location information and measure the signal. A 3D technique is possible by adding a slice encoding gradient in the direction of the slice selection gradient to the 2D method. The slice encoding gradient also change..

(영어/영문/English) The gradient echo (GRE) does not use two RF pulse waveforms, 90º and 180º, like spin-echo, but mainly uses one RF pulse waveform smaller than 90º to obtain an image from the FID signal. First, place the longitudinal magnetization with the transverse magnetization with the RF pulse waveform of aº, then dephase the spins by applying a negative gradient in the frequency direction, a..