1
Instrumentation
There will be 15 questions on instrumentation in the advanced-level examination for MRI. These will be drawn from the following subject areas
- Electromagnetism
– Faraday’s Law
– Types of magnet (superconductive, permanent, resistive)
- Radio frequency system
– Coil configuration
– Transmit and receive coils
– Transmit and receive bandwidth
– Coil tuning
– Pulse profile
- Gradient system
– Coil configuration
– Amplitude (+,–)
– Rise time
Q1 The liquid cryogen/s commonly used to maintain the magnet coil at superconducting temperature is/are:
| (a) | Helium |  |
| (b) | Hydrogen |  |
| (c) | Nitrogen |  |
| (d) | a and c |  |
Q2 Some systems use only one cryogen. In such systems, the cryogen is:
| (a) | Nitrogen |  |
| (b) | Hydrogen |  |
| (c) | Helium |  |
| (d) | Oxygen |  |
Q3 Faraday’s Law of Induction states that if a loop of wire is moved through a magnetic field, it will create, in the wire:
| (a) | A magnetic wave |  |
| (b) | A voltage |  |
| (c) | Torque |  |
| (d) | Resonance |  |
Q4 According to Faraday’s Law of Induction, the amount of current produced in a loop of wire moving through a magnetic field is proportional to:
| (a) | The length of the wire |  |
| (b) | The strength of the magnetic field |  |
| (c) | The spin density of the wire |  |
| (d) | The time it takes for the magnetic field to reach full potential |  |
Q5 In a typical superconducting magnet, the direction of the magnetic field is:
| (a) | Vertical |  |
| (b) | Horizontal |  |
| (c) | Around the flux lines |  |
| (d) | Hard to measure |
