Comparative analysis of high field MRI and histology for ex vivo whole organ imaging: assessment of placental functional morphology in a murine model.

OBJECTIVES: The purpose of our study was to evaluate MRI as a tool to examine placental morphology in a murine model in comparison to classical histology techniques.

METHODS: Assessment of placental samples (n = 24) from C57Bl/6 J mice was performed using MR imaging and histomorphological analyses. To optimize image contrast for MRI, a protocol for gadolinium-mediated enhancement of placental tissue was established. To test method sensitivity, placental zone assessment with MRI and histology was applied to a model of prenatal stress exposure known to affect placental morphology (n = 10). Mean data acquisition time for both methods was estimated. Difference between groups was calculated using the Mann-Whitney U test.

RESULTS: Tissue fixation with formaldehyde and staining with gadolinium resulted in the best image quality. Placental functional zones were identified and measured with both MRI and histology. MRI and histology were able to detect changes in the L/Jz ratio upon a prenatal stress challenge (p = 0.001; p = 0.003). Data acquisition time was shorter using MRI assessment.

CONCLUSIONS: Ex vivo MRI analyses of murine placental functional morphology with MRI are feasible and results are comparable to time-consuming histology. Both MRI and histology allow the detection of experimentally induced morphological tissue alterations.