Figure 2.

An MRI view of the hornet with details of its gaster is presented. A sagittal slice (top picture) and four axial slices (a – d) of different hornets. The dotted white lines in the sagittal image suggest the anatomical location and orientation of each axial slice. The theoretical resolution in the MRI images can be obtained by dividing the field of view (FOV) by the number of matrix elements. This yields 35 μm for the resolution of the axial images and 88 μm for that of the sagittal images. Any organs or tissue elements whose size or typical pattern is smaller (such as small tracheae), will not appear in the image, and its signal contribution will be averaged with those of other small nearby elements. Such a tissue element will be presented in the image by the typical gray scale level of this average, rather than by any fine structure. It is emphasized that this loss of information does not result in a loss of signal, but in a non-resolved dispersion of the fine-structured signal. However, the black areas in the image (which correspond to zero signal intensity) can only be the result of a near-zero concentration of water spins, i.e. air-spaces within the body of the hornet or the MRI-transparent liquid that surrounds this body.