Enhanced maximum intensity projection (eMIP) for improving the fidelity of optoacoustic images

Three-dimensional (3D) image reconstructions are often rendered as two-dimensional images, using maximum intensity projections (MIPs). However, MIP's rendering fidelity depends on the alignment of the individual slices along the projection direction. Also, the presence of noise and artifacts affects the contrast and the projected image elements. We introduce enhanced MIP (eMIP), a methodology that aligns the boundaries (e.g., skin boundary) of adjacent slices of the 3D volume onto the same coordinate system assumed by MIP (e.g., same depth) and applies robust contrast adjustment to normalize the intensities of the projected slices. We benchmark eMIP on 1725 clinical scans of human skin, using raster-scan optoacoustic mesoscopy (RSOM) that were assessed by 8 experts. Our results show that eMIP facilitates interpretability compared to conventional MIP and increases consistently the perceived image quality. The improved diagnostic ability of eMIP has the potential to replace MIP in RSOM and similar modalities.