A patient is presenting with severe radiating lower back pain and leg numbness, suggesting a herniated lumbar disc compressing the spinal nerve roots. The spinal canal and nerve roots are soft, water-rich structures housed deep within the dense, bone-shielded lumbar vertebrae.

Three imaging modalities are available for evaluation:

• a Magnetic Resonance (MR) scan
• a Computed Tomography (CT) scan
• an ultrasound scan

Discuss the advantages and disadvantages of each option in relation to this specific clinical presentation. In your answer, you should:

• refer to the physical principles and the relevant quality of the image obtained from each scan
• identify other factors (including safety, cost, and patient experience) that should be considered
• justify the type of scan you would recommend.