ARMRIT Physics Practice Exam With 100% Correct And Verified Answers 2024, Exams of Advanced Education

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ARMRIT Physics Practice Exam With

100% Correct And Verified Answers 2024

The tissue characteristic that depends heavily on the relative content of fat molecules and free water is: - Correct Answer-Hydrogen concentration. T1 is the measurement of time for the longitudinal component of the net magnetization vector to recover what percentage of its original value after the application of a 90 degree radio-frequency pulse? - Correct Answer-63% Immediately after an initial 90 degree radio-frequency pulse is turned off, the hydrogen protons will begin to: - Correct Answer-Dephase A 90 degree radio-frequency pulse will alter the net magnetization vector. Another effect is: - Correct Answer-The hydrogen protons will dephase The basic process of MR signal generation contains two basic steps, they are: - Correct Answer-Stimulation and relaxation. An equation derived to predict the MR signal intensity of a particular tissue as the result of a Spin-echo pulse sequence is the: - Correct Answer-Bloch equation The component Mxy is most associated with: - Correct Answer-Transverse to B0; T relaxation; transverse magnetization After a 90 degree radio-frequency pulse, the net magnetization vector begins to return to equilibrium. When the NMV is half-way between transverse and equilibrium, what are the magnitudes of the longitudinal component and the transverse component? - Correct Answer-Longitudinal component = greater than zero/transverse component = greater than zero. When is the net magnetization vector at its maximum magnitude? - Correct Answer-At equilibrium. The Larmor frequency of hydrogen protons in a 1.5 Tesla magnetic field is: - Correct Answer-63.9 MHz/Tesla. To describe the uniformity of the MRI system's main magnetic field, the term employed is: - Correct Answer-Homogeneity. Tissues that are very efficient at spin-lattice interactions near the Larmor frequency, such as fatty tissues, should have: - Correct Answer-Low T1 values and produces hyperintense signals

During the relaxation process, the MR signal grows weaker. This signal loss is known as: - Correct Answer-Free Induction Decay In a large main magnetic field such as those employed in MRI, the motion of a hydrogen proton has been described as wobbling like a spinning top. This motion is called: - Correct Answer-Precession Which type of electromagnetic coils are employed as a transmitter, receiver or both? - Correct Answer-radio-frequency coils Which type of MRI magnet requires no electricity to maintain its magnetic field and can weigh from 18,000 lb. to 200,000 lb.? - Correct Answer-permanent Which type of electromagnetic coils can be found both inside and outside of the housing of the MRI magnet? - Correct Answer-radio-frequency coils MRI systems require rooms that provide specific shielding requirements. These rooms are lined with what type of materials? - Correct Answer-Copper or galvanized steel. Because of the spinning motion of the hydrogen proton it has the same properties as a bar magnet. The hydrogen proton's spinning motion gives it a: - Correct Answer- Magnetic moment. Methemoglobin and gadolinium based contrast agents have magnetic properties that shorten both T1 and T2 values in adjacent tissues. What type of substances are they? - Correct Answer-Paramagnetic. Fast transition phenomenon and entry phenomenon are theories that explain which of the following tissue characteristics? - Correct Answer-velocity effects Because of only a 10-15% variation in most tissues, the tissue characteristic that does not provide much contrast resolution is: - Correct Answer-Hydrogen concentration. Which type of MRI magnet requires cryogen to cool magnetic coils to 4 degrees Kelvin?

• Correct Answer-superconductive In comparison to Computed Axial Tomography, an advantage of MRI is: - Correct Answer-Superior soft-tissue contrast resolution. Which type of receiver radio-frequency coil is placed close to a patient's body for the purpose of imaging superficial anatomic structures? - Correct Answer-Surface coils. Of the following radio-frequency pulse flip-angles, which is the smallest that will produce the maximum signal? - Correct Answer-30 degree.