The ornamental design for a mriheadcoil apparatus, as shown and described.
FIG. 1 is a perspective view of a MRI head coil apparatus showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a side elevation view thereof;
FIG. 5 is an opposite side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a top perspective view thereof.
The broken lines immediately adjacent the shaded areas represent the bounds of the claim, while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.