Question

Discuss the sensitivity and specificity of these imaging modalities.

Hint:

MRI and PET/CT have high sensitivity for detecting early and active disease, making them valuable in assessing multiple myeloma, especially for soft tissue and extramedullary involvement.

Answer 1

Step 1: Sensitivity and Specificity Overview.
Sensitivity refers to the ability of a test to correctly identify those with the disease (true positives), while specificity refers to the ability of the test to correctly identify those without the disease (true negatives). The sensitivity and specificity of imaging modalities in MM vary: 1. X-ray (Radiography): X-rays have a relatively low sensitivity (about 50-70%) for detecting early bone lesions, meaning they may miss small or early-stage lesions. Their specificity is higher, meaning they are good at confirming large lesions, but they are not as useful for detecting minimal or early disease.
2. MRI: MRI is highly sensitive (approximately 80-90%) for detecting bone marrow involvement, making it an excellent tool for early diagnosis. However, its specificity can be lower, as it may pick up non-specific changes that are not related to myeloma.
3. PET/CT: PET/CT has high sensitivity for detecting metabolic activity in lesions, including extramedullary disease. Its specificity is also high, as it can differentiate between active disease and benign processes. PET/CT is especially valuable in detecting relapse or residual disease.
4. CT: CT scans are highly sensitive for detecting structural bone lesions and are useful for identifying areas of cortical bone destruction. Their specificity is also good, but CT is not as sensitive for detecting soft tissue lesions compared to MRI.