Table 5.
Key points to consider in histology, ex vivo MRI, iron-based sequences and image coregistration, in order to limit methodological problems and to compare studies.
| Ex vivo MRI | Iron-based sequences | Histology | Image coregistration |
|---|---|---|---|
| Time between death and MRI (fresh) | Spatial resolution | Slice thickness | Image file formats |
| Time between death and fixation (fixed) | Slice thickness | Staining protocol | Up- or downsampling image resolution |
| Fixation period before MRI | Acquisition time | Type of staining | Non-linear transformation? |
| Fixative agent | NSA | Fixation time between MRI and histology | Stack procedure? |
| Degree of putrefaction | Number of echoes (relaxometry) | Tears | Color deconvolution? |
| Imaging solution | Echo time (relaxometry) | Stretching | Thresholded out background |
| Rehydration or not (fixed) | Post-processing algorithms (QSM) | Shrinkage | Grayscale conversion |
| Rehydration time (fixed) | Distortions | ||
| Room temperature | Swelling | ||
| Air/tissue interface (bubbles) | Blood vessel or paravascular space dilation | ||
| Contention technique to avoid vibrations | Knife mark | ||
| Specimen orientation | Sampling | ||
| RF coil type | |||
| Intravascular blood clot or paravascular space dilation |
NSA, number of signals averaged; QSM, quantitative susceptibility mapping; RF, radiofrequency; ROI, region of interest.