Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
MRI Midterm
| Question | Answer |
|---|---|
| WHICH MR FIELD HAS A BURN HAZARD? | RF |
| PATIENT ARRIVES TO MR DEPARTMENT AND INFORMS YOU THAT THEY HAVE A HEART VALVE. WHAT IS YOUR FIRST QUESTION? | Do you have a card? When and where was your surgery? Have you ever had an MRI before? |
| Patient arrives to MRI department and tells you they have metal in their body from foreign war. Is it safe to scan them? | No, most metals from foreign war are made of unknown material which could be hazardous in the MRI field |
| How often should a patient be screened for an MRI exam? | every time |
| Which MR zone is for the general public? | zone 1 |
| Which labeled item can be brought into zone 4 without concern? MR safe, MR conditional, or MR unsafe | MR safe |
| Patient is experiencing tingling and shocks in their fingers during the exam. What do you do? | Have them remove any conductive loops (unclasp hands, uncrossed ankles, stop touching sides of body with hands) |
| Patient arrives with skin staples on their head. You are imaging their knee. Can you scan this patient? | Yes, as long as you provide a heat sink for the staples and the patient is awake and alert |
| Patient is experiencing tingling and shocks in their fingers during the exam. What MR field is responsible for this? | Gradient magnetic field |
| Which magnet field produces the main magnetic field? What are the FDA’s limit on this field? | Static Magnetic field, 8T |
| Which MR field is responsible for the magneto-hydrodynamic effect? | static magnetic field |
| What term describes the boiling off of liquid helium? | quench |
| What is the FDA’s recommendation for max noise exposure? | 102 decibels |
| What is the gauss line the general public should be restricted to? | 9 gauss |
| Field strength of 3 Tesla is equal to how many gauss? | 30,000 gauss (1T = 10kg = 10,000 gauss) |
| what is the purpose of the static magnetic field? | to magnetize tissues |
| What is the gyromagnetic ratio of hydrogen? | 42.6 mHz/T |
| What is the precessional frequency of hydrogen in a 1.5 T MRI machine? | 63.9 mHz |
| What is the larmour frequency of hydrogen in a 3.0 T MRI machine? | 128 mHz |
| Name three tupes of primary magnets? | permanent, resistive, and superconducting |
| What type of primary magnet can never be turned off? | permanent |
| superconducting | |
| What is the term for when the net magnetization has been rotated at an angle from the z-axis after application of an RF pulse? | flip angle |
| free induction decay FID | |
| What are we imaging in MRI? Must be specific. | hydrogen protons as they exist in fat and water |
| What is it called when the Net magnetization vector is aligned with B0? | equilibrium |
| What is the liquid cryogen used in a superconducting magnet? | helium |
| What will hydrogen protons do when placed in a static magnet field? | align with the magnetic field or against it |
| Name two types of electromagnets? | resistive and superconducting |
| Name the secondary magnets used in the MRI system? | shim coils, RF system, and gradient system |
| What is it called when two local coils are used at the same time for imaging? | Helmholtz pair |
| What is the purpose of shimming? | homogeneity |
| What gradient is used for slice select in an axial image? | Z gradient |
| What gradient is used for the phase encoding in a sagittal image? | Y gradient |
| What is B1? | RF field |
| When a receive only coil is being used, what transmits the RF? | the main RF body coil that is housed with the gantry |
| What is the name for the center of the bore of the MR system? | isocenter |
| Name an example of a paramagnetic substance? | gadolinium, aluminum, manganese, platinum, tungsten, titanium |
| What is an example of a ferromagnetic substance? | iron, steel, nickel, cobalt |
| True or False: To achieve thin slices you need to use a steep gradient. | true |
| What gradient coil alters the magnetic field in the head to foot direction? | Z gradient |
| What does SNR stand for? | signal to noise ratio |
| What type of MR image is best to review anatomy? | T1 weighting |
| If a structure on an image displays bright white and you are reviewing a T2 weighted image, what is the structure? | fluid/water |
| An inversion recovery spin echo sequence begins with what type of pulse? | 180 degree pulse |
| In T2*, what is responsible for the shortening of the T2 times of tissues? | the dephasing mechanisms |
| In a spin echo sequence that collects more than one echo per TR period, what best describes the number of echoes collect per TR period? | echo train length |
| Which type of pulse sequence would you use if you needed to obtain a true T2 weighted image? | spin echo |
| What type of tissues does a STIR image suppress? | STIR – fat, FLAIR – CSF |
| What imaging techniques collects more than one row of k-space using special multiple channel coils? | parallel imaging |
| What is the disadvantage of utilizing fast spin echo pulse sequences? | heat |
| The time required for 63 % of the tissue’s longitudinal magnetization to recover is known as? | T1 weighting/longitudinal relaxation/spin-lattice relaxation |
| The time required for 63% of the tissue’s transverse magnetization to decay is known as? | T2 image weighting/transverse decay/transverse relaxation |
| On what image type will fat be bright? | T1 weighted and PD weighted |
| When looking at a T2 weighted image, how would you describe the contrast appearance of water? | bright |
| What TR and TE is used to achieve T1 weighting? | short and short |
| What TR and TE is used to achieve T2 weighting? | long and long |
| What TR and TE is used to achieve PD weighting? | TR long TE short |
Created by:
user-2058008