MRI Cheat Sheet 2026

The 30 highest-yield MRI facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the relationship between voxel size and SNR in MRI? → Larger voxels produce higher SNR
2. Inversion recovery sequences null a specific tissue when the readout pulse is applied at time TI equal to: → 0.693 × T1 of the tissue (T1 × ln2)
3. In MR imaging, the signal-to-noise ratio (SNR) improves with increasing field strength approximately as: → Linearly (proportional to B0)
4. A 'DC offset' or 'center dot' artifact seen as a bright spot in the center of the image is related to: → A small DC current offset in the receiver causing a spike in the center of k-space
5. A patient is claustrophobic and anxious before their MRI. Which non-pharmacological intervention is most appropriate first? → Explain the procedure, offer a patient communication system, and consider feet-first entry
6. Fast spin echo (FSE/TSE) sequences reduce scan time compared to conventional spin echo by: → Acquiring multiple phase-encoding lines after each 90° excitation (echo train)
7. What does 'isotropic voxel' mean in MRI acquisition? → Voxel with equal dimensions in all three spatial directions
8. During an MRI exam, a patient begins experiencing intense burning sensations on their skin near monitoring cables. What is the most likely cause? → RF-induced heating from looped or coiled cables
9. What is the effect of reducing the number of phase-encoding steps while keeping FOV and frequency steps constant? → Scan time decreases and phase-direction spatial resolution decreases
10. For MRI of the breast, the patient should be positioned in which orientation? → Prone with breasts hanging freely in a dedicated bilateral breast coil
11. Diffusion tensor imaging (DTI) and tractography are primarily used to evaluate which brain structure? → White matter fiber tracts and connectivity
12. What is the purpose of crusher (spoiler) gradients in a spin echo sequence? → To dephase residual transverse magnetization before the next RF pulse
13. For MRI of the internal auditory canals (IACs), which imaging plane is most commonly used as the primary plane? → Axial
14. Which parameter in MRI controls the field of view (FOV) and therefore directly affects spatial resolution when matrix size is held constant? → FOV size relative to matrix (voxel size = FOV/matrix)
15. MR Conditional implants are safe to scan only when: → Specific conditions of field strength, SAR, and gradient limits are met
16. Which of the following changes will increase spatial resolution without changing the FOV? → Increasing the matrix size
17. Multiple sclerosis (MS) plaques in the brain are classically found in which location on MRI? → Periventricular white matter, corpus callosum, and juxtacortical regions
18. Wraparound (aliasing) artifact in MRI is caused by: → Structures outside the FOV contributing signal that is folded back into the image
19. Which of the following is NOT an acceptable primary pathway for ARRT MRI registry eligibility? → Hold an associate degree only with no primary ARRT credential
20. The echo time (TE) in gradient-echo sequences affects which type of contrast? → T2* contrast — longer TE increases T2* weighting and susceptibility effects
21. A technologist wants to reduce scan time while maintaining similar SNR. Which strategy is most effective? → Use parallel imaging (SENSE/GRAPPA)
22. In MRI, what does the term 'bandwidth' typically refer to in clinical practice? → The range of frequencies sampled during readout, affecting SNR and chemical shift
23. Which sequence parameter directly controls the slice thickness in a 2D spin-echo acquisition? → Bandwidth of the RF pulse divided by the slice-select gradient amplitude
24. What is the effect of increasing the echo time (TE) on T2-weighted images? → Increases T2 weighting by allowing more transverse relaxation
25. Which MRI screening form section is most critical for identifying implanted devices that may be MR Unsafe? → Implants and devices section
26. This kind of magnetic shielding confines the main magnet's field by using other magnets and their corresponding magnetic fields. → Active
27. Which technique is most effective for reducing susceptibility artifact from a metallic implant in MRI? → Use a spin-echo or fast spin-echo (FSE) sequence with narrow bandwidth
28. IV line tubing and monitoring cables used inside the MRI suite must be: → MR-conditional equipment specifically rated for use in the magnetic field
29. Which property of hydrogen makes it the most commonly used nucleus in clinical MRI? → High natural abundance and large magnetic moment
30. Which MRI sequence is best suited for evaluating articular cartilage because it provides excellent contrast between cartilage, fluid, and bone? → Proton density fat-saturated (PD FS)