ARMRIT Practice Tests with Complete Questions & Answers (Graded A+)

The 2 types of enhancement media described by Lauffer, the mechanism of T1 agents is - ANSWER-to decrease T1 relaxation time, thus emitting high signal An analogy for the decoding of the MR signal through Fourier Transform - ANSWER-Basilar membrane processing sound Logically each line of phase encoding data is combined to allow the FT to determine the position along the y-axis. The number of phase encoding steps determines - ANSWER-the number of pixels along the y-axis In a gradient echo pulse sequence, which flip angle will produce a T2 weighted gradient echo image. - ANSWER->20 - <45 degree flip angle In a horizontal magnet, what is the primary Gs (slice select gradient) for an axial slice - ANSWER-Gz (axial slice) A linear relationship between frequency and position is superimposed on Bo by the Gp (phase encoding gradient). The Hydrogen protons relative precessional frequencies determine - ANSWER-phase shifts Combining a metal ion with a ligand reduces their tendency to bind to proteins, enzymes, or membranes. The degree to which they dissociate is a measure of their - ANSWER-toxicity In a phase sequence employing 2DFT, the time can be calculated using which formula - ANSWER-TR x NEX x Matrix What pulse imaging technique is in all implementations of MRA - ANSWER-gradient echo What year was the first MRI enhancement agent approved for clinical use - ANSWER-1988 Increasing NEX - ANSWER-Increase SNR and Resolution Inversion time, in an IR pulse sequence, is the time interval between the - ANSWER-180 degree and 90 degree pulses Increasing the matrix - ANSWER-increase resolution A pulse sequence that replaces the second RF pulse with a gradient magnetic field to rephase the transverse vector and produce and echo is called - ANSWER-gradient echo Increase FOV, TE, Slice thickness does - ANSWER-not affect scan time In spatial localization which factor most affects slice thickness and position - ANSWER-bandwidth and strength of Gs (slice select gradient) The two types of enhancement media described by Lauffer, the mechanism of T2 agents is - ANSWER-to decrease T2 relaxation time, thus emiting a high signal