Moderate MAC thickness falls into which range?

• A. 3-5 mm
• B. 6-10 mm
• C. 11-15 mm
• D. 0-2 mm

Answer: (B)

Mitral annulus calcification (MAC) is a calcium buildup in the fibrous ring around the mitral valve. In echocardiography, the extent of MAC is graded by how thick the calcified ring appears. Moderate MAC thickness is typically about 6 to 10 millimeters. This sits between mild calcification (roughly 3–5 mm) and more extensive, severe calcification (often >10 mm). Knowing the thickness helps in risk assessment and planning, because a thicker, more extensive MAC can affect valve function and make procedures involving the mitral valve more challenging. On ultrasound, MAC appears as bright, echogenic areas along the annulus with shadowing, and thickness is measured at the thickest portion of the calcified ring.