Which diagnostic procedure is LEAST likely to confirm suspected disc herniation in a patient with low back pain?

Which diagnostic procedure is LEAST likely to confirm suspected disc herniation in a patient with low back pain?

• A. MRI scan
• B. CAT scan
• C. Radiograph
• D. Myelogram

Answer: (C)

The key idea is that disc herniation is a soft-tissue problem, so imaging that shows soft tissues is needed to confirm it. MRI provides the best visualization of intervertebral discs and nerve roots, making it the most sensitive test for detecting a herniation and the associated nerve compression. CT scans can also reveal herniations, especially when bone detail is important or when MRI isn’t available, though they’re more focused on bone and may be less sensitive for small disc protrusions. Myelography (with contrast) followed by imaging can show compression of the thecal sac or nerve roots, helping confirm a disc-related effect, but it’s invasive and less commonly used today. Plain radiographs, on the other hand, visualize bone structures and alignment; they do not show the discs or nerve roots directly, so they are unlikely to confirm a disc herniation. They’re useful to rule out fractures or severe degenerative changes but not to diagnose a herniated disc.

The key idea is that disc herniation is a soft-tissue problem, so imaging that shows soft tissues is needed to confirm it. MRI provides the best visualization of intervertebral discs and nerve roots, making it the most sensitive test for detecting a herniation and the associated nerve compression. CT scans can also reveal herniations, especially when bone detail is important or when MRI isn’t available, though they’re more focused on bone and may be less sensitive for small disc protrusions. Myelography (with contrast) followed by imaging can show compression of the thecal sac or nerve roots, helping confirm a disc-related effect, but it’s invasive and less commonly used today. Plain radiographs, on the other hand, visualize bone structures and alignment; they do not show the discs or nerve roots directly, so they are unlikely to confirm a disc herniation. They’re useful to rule out fractures or severe degenerative changes but not to diagnose a herniated disc.