What type of resolution is most affected by the mechanical focus on a linear array transducer?

• A. Lateral resolution
• B. Contrast resolution
• C. Temporal resolution
• D. Elevational resolution

Answer: (D)

Elevational resolution. Mechanical focusing on a linear array shapes the beam in the elevation (slice-thickness) direction, narrowing the beam’s thickness at the focal depth. This directly improves the ability to distinguish structures that are stacked in the elevational dimension, i.e., the slice thickness. Lateral resolution depends on beam width within the imaging plane and is influenced by aperture and electronic focusing, not primarily by the mechanical elevation focus. Temporal resolution relates to frame rate, and contrast resolution concerns image gray-scale discrimination, not beam thickness. So the mechanism of mechanical focus most enhances elevational resolution.