ARMRIT Clinical Application Exam: Questions with 100% Correct Answers, Exams of Advanced Education

Download ARMRIT Clinical Application Exam: Questions with 100% Correct Answers and more Exams Advanced Education in PDF only on Docsity! ARMRIT- Clinical Application Exam Questions With 100% Correct Answers 2024 A technique to avoid "cross-talk"? - Correct Answer- Interleaving Combining a metal ion with ligand reduces tendency to bind to proteins, enzymes or membranes. The degree to which they dissociate is a measure of their? - Correct Answer- Toxicity The "best" technique for improving image quality is to increase? - Correct Answer-NEX Tissues that have low (short) relaxation times have? - Correct Answer-High (long) relaxation rates Linear relationship between frequency and position is superimposed on Bo by the Gp. The hydrogen protons relative precessional frequencies determine? - Correct Answer-Phase shifts What is the pixel formula? - Correct Answer-FOV/Matrix An analogy for decoding the MR signal through Fourier Transform? - Correct Answer-Basilar membrane processing sound Decreasing Matrix will? - Correct Answer-Decrease pixel size Spatial resolution is an image quality factor determined by? - Correct Answer-Slice thickness and pixel size Inversion time, in Inversion Recovery pule sequence is the interval between? - Correct Answer-180 and 90 degree pulses Decreasing TE will? - Correct Answer-Increase # of slices The least expensive parameter in time, of the following that affect time, to increase for improving image quality is? - Correct Answer-TR FLAIR stands for? - Correct Answer-Fluid Attenuated Inversion Recovery In a horizontal field magnet, what is the primary Gs for Sagittal slice? - Correct Answer-Gx Lauffer: T1 agent? - Correct Answer-To increase T1 relaxation time, thus emitting high signal- hyperintense Lauffner: T2 agent? - Correct Answer-To increase T2 relaxation time, thus emitting low signal- hypointense What determines Slice selection- Gs? - Correct Answer- Strength of slope and Bandwidth of RF pulse The tissue characteristic which depends more on state (solid, liquid, gas) of a tissue than any other? - Correct Answer-T2 effects Immediately after an initial 90 degree RF pulse is turned off, hydrogen protons will? - Correct Answer-Dephase Once in Bo, majority of the hydrogen protons will? - Correct Answer-Align themselves parallel to Bo Equation derived to predict signal intensity? - Correct Answer- Bloch In MR, a chemical substance to be affected by Bo and radio- wave it must contain? - Correct Answer-Off # of total protons and neutrons T2* effects have no effect on T2 decay? - Correct Answer-True Different tissues that have signals that appear similar on an MR image are described as? - Correct Answer-Isointense The tissue characteristic that is dependent on the strength of the main magnetic field and temperature is? - Correct Answer- T1 effects The components of a gyro-magnetic ratio are? - Correct Answer-Magnetic momentum and Angular momentum Tissue characteristic that provides more tissue contrast and pathological information is? - Correct Answer-T2 effects On a basic level, 3 components of MRI are? - Correct Answer- Magnetic field, proton, and radio-wave In main magnetic field, protons that are parallel and anti- parallel will have what effect? - Correct Answer-Cancel each other out The tissue characteristic that depends heavily on content of fat molecules and free water is? - Correct Answer-T1 effects In GE, which flip angles will produce T2W images? - Correct Answer->20- <45 degrees A gradient is employed exposing patients body to a series of increasing/decreasing magnetic field strengths for slice selection. In what relation to the slice is the gradient? - Correct Answer-Perpendicular Parameters for Proton density? - Correct Answer-Long TR short TE 180 degree RF pulse is used to obtain? - Correct Answer-Spin echo signal Thermal equilibrium is when? - Correct Answer-Protons precess out of phase 90 degree RF pulse will? - Correct Answer-Will shift NMV in size and direction (away from equilbrium) Hydrogen protons will have phase coherence Introduction of a 90 degree RF pulse is? - Correct Answer- Resonance T2 contrast enhancement agent is to? - Correct Answer- Decrease T2 relaxation which decreases signal How are the effects of Bo inhomogenities on a FID signal corrected for in a Spin-Echo? - Correct Answer-By applying a second RF pulse of 180 degrees Substances respond to a specific RF known as? - Correct Answer-Resonance frequency The amount of RF needed to produce a flip angle of 90 degrees is determined by? - Correct Answer-Amplitude of the RF pulse, duration, and strength of Bo Susceptibility effects are reduced by? - Correct Answer- Lowering TE To decrease magnetic susceptibility, use? - Correct Answer- TSE FSE spin echo What pulse sequence is best for brain hemorrhages? - Correct Answer-GE To diminish Gibbs/Truncation artifact? - Correct Answer- Increase Matrix, NEX and Phase shift Chemical artifacts are high when? - Correct Answer-High magnetic fields, low bandwidths, high pixel size Signal must be sampled twice per cycle? - Correct Answer- Nyquist theorem K space filled each line with TR - Correct Answer-CSE dB/dt - Correct Answer-muscular twitches that occur with EPI and DWI Spatial resolution is affected by? - Correct Answer-Voxel volume, FOV, matrix, slice thickness Acquisition time has its greatest impact on? - Correct Answer- Patient motion ETL: - Correct Answer-# of times 180 degree rephasing pulse is applied and echo is sampled per TR period FSE is controlled by? - Correct Answer-Effective TE Receive bandwidth (x2)? - Correct Answer-40% SNR lost Receive bandwidth (/2)? - Correct Answer-40% SNR gained CSE - Correct Answer-1 line of K space per TR 90...180 FSE - Correct Answer-2+ lines of K space per TR (ETL) Single shot (FSE) uses? - Correct Answer-Partial fourier "DRIVE" (FSE) - Correct Answer-Driven Equilibrium fourier Reverse flip < Transverse plane to longitudinal plane (Mxy -> Mz) Steady state pulse sequence contains? - Correct Answer-2 excitation pulses RTM- partial transverse longitudinal magnetization all the time * NMV never returns to longitudinal axis Stimulated echo sequence contains? - Correct Answer-2 excitation pulses and flip angle Hann Echo sequence contains? - Correct Answer-2 excitation pulses of 90 degree Incoherent - Correct Answer-FID T1/PD Spoiling gradient: RF and gradient (3) Coherent - Correct Answer-FID/RTM T2* Rewinder gradient Steady state free precession - Correct Answer-RTM T2 (truer) Rewinder gradient FGE - Correct Answer-Shorter TE, samples a portion of the echo using "partial echo technique" Single breath hold in 1 acquisition BGE - Correct Answer-Larger flip angles to correct phase errors from flowing blood Good for vessels, spinal cord and IAC's EPI - Correct Answer-Blipped/constant FASTEST form of data acquisition Perfusion, Diffusion and Spectroscopy During FSE, central lines of K space are associated with? - Correct Answer-Constant data and effective TE Explain Keyhole K space filling? - Correct Answer-Outer before contrast Inner after contrast Angiograph studies FFT converter does what? - Correct Answer-Converts frequency time to frequency amplitude Before/after going into K space (array processor) MIP - Correct Answer-Ray passes through- gray scale What shows more phenomenon? - Correct Answer-In-flow effect (entry slice) MRA enhances blood flow, flowing perpendicular to a stack of slices by saturating signals from stationary spins? - Correct Answer-TOF (incoherent gradient) Normal blood signal is ? - Correct Answer-High Occluded blood signal is? - Correct Answer-Low VENC low - Correct Answer-Venous flow VENC high - Correct Answer-Arterial flow DWI; directional - Correct Answer-Ansiotropic- white matter DWI; non-directional - Correct Answer-Isotropic- gray matter DWI - Correct Answer-Gradient application before and after 180 degree RF pulse Diffusion - Correct Answer-Movement in extracellular Random thermal motion Greatest DWI? - Correct Answer-500-1500 Restriced diffusion vs Free diffusion - Correct Answer- Restricted- pathology Free diffusion- normal tissue DTI - Correct Answer-multi gradient; demonstrates direction of ansiotropic (white matter) Perfusion - Correct Answer-visualizes blood that does into 1 gram of tissue Low levels of perfusion mean? - Correct Answer-Pathology What is the greatest effect on flow phenomenon? - Correct Answer-Directional flow Spectroscopy - Correct Answer-Chemical spectrum *helps determine disease 1st law of electromagnetism? - Correct Answer-Faraday; Law of electromagnetic Induction Voltage into a loop creates magnetic field 2nd law of electromagnetism? - Correct Answer-Lenz; Eddy currents Induced currents; opposing magnet field = original current Pulse profile - Correct Answer-Visual representation of RF by MRI What is achieved when there are more protons aligned in a low energy state than in a high energy state? - Correct Answer-Equilibrium magnetization Low energy protons - Correct Answer-spin-up/ parallel T1W increases SNR increases Slice thickness decreases - Correct Answer-Scan AREA decreases SNR decreases Resolution increases Slice thickness increases - Correct Answer-Scan AREA increases SNR increases Resolution decreases TE decreases - Correct Answer-# of slices increases T2W decreases SNR increases Slice interval decreases - Correct Answer-Scan AREA decreases Matric increases - Correct Answer-Scan TIME increases Resolution increases SNR decreases # of slices decreases - Correct Answer-Scan AREA decreases TE increases - Correct Answer-T2W increases # of slices decreases SNR decreases FOV increases - Correct Answer-Scan AREA increases SNR increases Resolution decreases As TE ____, TOF _____ - Correct Answer-