The ornamental design for an mriheadcoil apparatus, as shown and described.
FIG. 1 is a perspective view of an MRI head coil apparatus depicting a a new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is an opposite side 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.