RADIOLOGIV TECHNOLOGY 4912 COMPREHENSEIVE REVIEW/MRI WORSHEET #1- PATIENT CARE AND SAFETY/PHYSICAL PRINCIPLES 1. What are potential consequences to patients and personnel should there be a release of gaseous helium within the scan room. 2. A bluish color to the skin, mouth, gums and nail beds is a sign of what condition? 3. Ear protection is recommended due to noise produced by what system? 4. What are acceptable techniques for identifying or excluding an intraocular metallic foreign body? 5. The ability of the fringe field component of the static magnetic field to attract ferromagnetic objects into the MR system with considerable force is known as 6. The confining dimensions of the MR system, prolonged examinations, gradient induced noise, and distress related to the restriction of movement can lead to 7. What precautions should be taken to ensure a nursing child does not receive any trace of gadolinium? 8. What are some minor reactions to the administration of an intravenous MR contrast agent? 9. What substance will decrease the T1 and T2 relaxation times in a tissue? 10. What is the maximum allowable SAR for small volume imaging in the United States? 11. Name several implants which are absolute contraindications for MR study. 12. What is the most frequent complication with the use of sedatives and anesthetics? 13. The FDA guidelines limit gradient field strength to 14. The formation of a conductive loop with the patient, coil cabling, or EKG leads can cause 15. The FDA limits the increase in a patient s core temperature, due to the FR exposure to
16. The Specific Absorption Rate (SAR) is dependent on what factors? 17. A contrast reaction involving respiratory, cardiovascular and cutaneous manifestations (uticaria) is termed 18. The method by which RF absorption is measured is called 19. What is the maximum allowable SAR for the head in the United States? 20. How does the static magnetic field affect an EKG? 21. What can be induced in a patient by the application of gradient fields? 22. What effects have been seen in patients experiencing time varying magnetic fields? 23. What is the maximum allowable SAR for whole body imaging in the United States? 24. Individuals with pacemakers should remain outside which fringe field line? 25. What is the normal range for adult blood pressure? 26. Name the event that involves a sudden loss of superconductivity resulting in the vaporization of liquid cryogens. 27. What energy source imports heat into the body tissues causing them to heat up? 28. The relaxation process in which energy released by one proton is absorbed by another is called 29. The time interval between the beginning of a pulse sequence and beginning of the succeeding pulse sequence. 30. The system used to visualize the net magnetization vector (NMV) in a three dimensional environment. 31. What occurs as a result of resonance (the NMV absorbing RF energy)? 32. The position of a magnetic moment on its precessional path at any given time is called 33. What is the condition In which all the nuclei in the net magnetic moment (NMV) are at the same place at the same time on their precessional paths around Bo?
34. Which portion of the K-space contains data with low spatial resolution? 35. What is the axis of the Cartesian coordinate system which is parallel to Bo? 36. What is the axis of the Cartesian coordinate system which is perpendicular to Bo? 37. A device which receives MR signal from a localized area is called 38. A device which transmits RF and receives the MR signal is called 39. The stray magnetic field outside the bore of the magnet is known as the 40. What process must be done to compensate for fringe fields? 41. What material can be used to confine the fringe field to the area of the scan room? 42. What type of shielding utilizes additional solenoid magnets outside the cryogen bath 43. The range of frequencies sampled during readout is known as 44. A steep phase encoding gradient will cause what type phase shift between two points along the gradient? 45. Which RF pulse will impart the most energy to precessing nuclei? A) 45 B) 60 C) 90 D) 160 46. What is the gyromagnetic ratio of hydrogen? 47. A shallow phase encoding gradient will cause what type of phase shift between two points along the gradient? 48. The magnetic field in a resistive magnet is generated by 49. The maximum field strength that can be achieved with a resistive magnet is 50. What are the two main clinical causes of magnetic susceptibility artifact? 51. A zipper artifact is caused by 52. The time delay which occurs between phase encoding and frequency encoding is the source of what type of artifact?
53. The process by which the Bo field is made as homogeneous as possible is called 54. The time required for a gradient to switch on, achieve the required gradient slope, and switch off again describes what gradient quality? 55. What is the relationship between the external magnetic field (Bo) and the signalto-noise ratio? 56. When is the slice selection gradient turned on in a spin echo pulse sequence? 57. When is the phase encoding gradient turned on during a spin echo pulse sequence? 58. What is the precessional frequency of hydrogen nuclei 1.5 T? 59. When is the frequency encoding gradient turned on? 60. Slice thickness and slice gap is determined by 61. The area where data is stored prior to Fast Fourier Transform (FFT) 62. The mathematical process by which acquired data is converted into an image is called 63. Where is the data with the highest signal amplitude stored K-space? 64. The time required for 63% of the longitudinal relation to be recovered by a tissue is called 65. From which RF pulse will full longitudinal recovery be fastest? a) 45 b) 60 c) 90 d) 180 66. The condition in which the majority of the hydrogen nuclei are aligned with the magnetic field is known as 67. What is the correct unit of measure of precessional frequency? 68. What is the precessional frequency of hydrogen nuclei at 1.0T? 69. Which portion of the K-space contains data with high spatial resolution? 70. What is the Lamour equation?
71. What is the relationship between precessional frequency and the external magnetic field strength? 72. What is the condition known as resonance? 73. Under what conditions can resonance be achieved? 74. What is the mathematical symbol for external field strength? 75. What is the unit for magnetic field strength? 76. What type of artifact is seen exclusively in both phase and frequency directions? 77. The area in which a gradient magnetic field is equal to the external magnetic field is called 78. The loss of phase coherence due to intrinsic and extrinsic magnetic field inhomogeneities is called 79. A substance which induces a small magnetic field about itself is referred to as 80. A substance which does not induce a small magnetic field about itself is referred to as 81. A substance which, once exposed to a magnetic field, becomes permanently magnetic, is referred to as 82. A device which transmits RF and receives the MR signal is called 83. What is the most common materials used in the construction of a permanent magnet? 84. The time required for 64% of the transverse magnetization to decay is called 85. A vector possesses which two properties? 86. Current passed in the same direction through two parallel wires will produce 87. What determines the amplitude of a gradient slop? 88. Superconductive systems require which of the following? A) High heat reservoirs B) Large amounts of ferromagnetic materials C) Cryogens D) A continuous electrical supply
89. Which portion of the K-space contains low spatial resolution and high signal amplitude? 90. Which of the following RF pulses will produce the largest component of transverse magnetization? A) 45 B) 60 C) 90 D) 180 91. An image in which the fat is bright and the CSF is dark is determined by the 92. What is the precessional frequency of hydrogen at.5t? 93. A device which transmits RF and receives the MR signal is called 94. Coils of a superconductive magnet are made of what material? 95. Truncation artifact is a result of 96. The process of nuclei releasing energy to the surrounding lattice is called 97. Where is the data with the lowest signal amplitude stored in the K-space? 98. The density and distribution of hydrogen nuclei within a particular tissue describes