 Frederick C. Cobey

Frederick C. Cobey studies quantitative cardiac imaging, including three-dimensional assessment of how the mitral valve leaflets meet during closure. He is first author of a 2014 primary study using transesophageal echocardiography to measure the valve's coaptation area and relate it to functional mitral regurgitation.^[ref] The published name and affiliations establish this contribution without expanding the middle initial.

The study examined 25 patients with functional mitral regurgitation undergoing cardiac operations. It used intraoperative two- and three-dimensional echocardiography, followed by offline measurement of the end-systolic coaptation zone and valve area.^[ref] The three-dimensional observation addresses an extended surface, rather than assuming that a single two-dimensional slice captures its full geometry.

The mitral coaptation index divides the measured coaptation zone area $A_c$ by the measured valve area $A_v$:An original normalization example takes $A_c=0.60\mathrm{c}{\mathrm{m}}^2$. Valve areas of 6 and $10\mathrm{c}{\mathrm{m}}^2$ then give indices 0.10 and 0.06, respectively. Equal coaptation area need not imply an equal proportion of the valve area. These are stipulated illustrations, not individual patient measurements from the paper.

If every reconstructed length is multiplied by the same scale factor $k$, both areas multiply by $k^2$ and the index is unchanged. The ratio consequently removes that common scale dependence. It does not remove a segmentation error affecting only the coaptation zone, nor does it compensate for measuring a different cardiac phase.

The primary study found an association between the index and the severity of functional mitral regurgitation in its examined sample.^[ref] Cobey's documented work connects an anatomical contact surface to a quantitative imaging observable. Its interpretation still depends on acquisition, surface identification and the population studied.