A 70-year-old woman with a history of veebral crush fracture presents to the osteoporosis outpatient clinic. Which of the following investigations is most useful to assess the extent of her osteoporosis?
**Core Concept**
Osteoporosis is a metabolic bone disease characterized by decreased bone density and quality, leading to increased risk of fractures. Assessing the extent of osteoporosis requires an investigation that measures bone mineral density (BMD).
**Why the Correct Answer is Right**
Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring BMD. It uses two X-ray energies to distinguish between bone and soft tissue, providing accurate and precise measurements of BMD at the lumbar spine and hip. This information helps assess the risk of future fractures and guide treatment decisions.
**Why Each Wrong Option is Incorrect**
**Option A:** Bone scans are used to detect bone metastases, infections, or fractures but are not suitable for assessing osteoporosis.
**Option B:** MRI is useful for detecting vertebral fractures but is not a primary tool for assessing osteoporosis or measuring BMD.
**Option C:** CT scans are useful for detecting vertebral fractures and assessing bone morphology but are not the primary investigation for osteoporosis.
**Clinical Pearl / High-Yield Fact**
The World Health Organization (WHO) defines osteoporosis as a T-score of -2.5 or lower on a DXA scan, indicating a significant decrease in bone density.
**Correct Answer: C. CT scans are useful for detecting vertebral fractures and assessing bone morphology but are not the primary investigation for osteoporosis.