Which term best describes a radiolucent lesion with a single focal center?

• A. Epicenter
• B. Single
• C. Unilateral
• D. Localized

Answer: (B)

Understanding how radiolucent lesions are described by number of centers helps here. When a lesion has only one radiolucent focus, the precise descriptor is single (unifocal). This term directly communicates that there is just one focal center, which is exactly what this description requires. The other terms don’t specify the number of centers: epicenter isn’t a radiology term, unilateral refers to being on one side rather than the number of foci, and localized describes the area affected but not whether there is one or multiple centers. So the best fit is single.