Figure 1.
Photograph of the Interferometer Setup at Beamline ID19, ESRF, Grenoble, France.
Monochromatic, coherent X-rays travel through the sample and introduce distortions in the interference pattern created by the phase grating. Those are evaluated by a lateral movement of the phase grating located behind the sample. Photograph adapted from I. Zanette, Interférometrie X à réseaux pour l'imagerie et l'analyse de front d'ondes au synchrotron, PhD thesis, University of Grenoble, 2011.
Figure 2.
Contralateral Control Kidney and Ischemic Kidney in three Different Contrast Modalities.
(a), (d) Phase contrast. (b), (e) Dark-field contrast. (c), (f) Attenuation contrast. All images are scaled individually for best visual appearance. (a) Phase-contrast images of the contralateral kidney allow to differentiate the functional compartments of the kidney. (d) Phase-contrast images of I/R kidneys show considerably less variation in gray value between the different compartments. Stripes of the outer medulla cannot be distinguished. The number of visible tubular structure or voids is highly reduced. In dark-field contrast, (b) control kidneys show scattering at interfaces, which is reduced in (e) I/R kidneys. Conventional absorption-based images show considerably lower contrast and relatively higher noise in both (c) control and (f) ischemic kidney. CO – cortex; OM – outer medulla; OSOM – outer stripe outer medulla; ISOM – inner stripe outer medulla; IM – inner medulla.
Figure 3.
Mean Gray Values of Kidney Compartments.
Mean value and standard deviations of phase gray values of the respective compartment. Note that OSOM and cortex were assessed together in healthy kidneys and OSOM and ISOM together in I/R kidneys. OSOM – outer stripe outer medulla ISOM – inner stripe outer medulla.
Figure 4.
Volumetry of Healthy and I/R Kidney.
Gray values are proportional to electron densities. (a) Histogram for both complete kidney volumes in comparison. (b) Histogram of healthy kidney and the contributions of the different compartments. (c) Histogram of post-ischemic kidney and the contributions of the different compartments. OSOM – outer stripe outer medulla; IS – inner stripe.
Table 1.
Volumetric data from three-dimensional segmentation of the functional compartments of the kidneys.
Figure 5.
Three-Dimensional Renderings of the Renal Vasculature.
(a) Healthy and (b) post-ischemic kidney from the segmented phase-contrast tomographies. The injured kidney shows a dramatic reduction of the vasculature.
Figure 6.
Comparison of a HE-Stained Histological Slice of Control Kidney.
Phase contrast images provide similar morphological information as a HE-stained slice. The different functional compartments (IM, ISOM, OSOM/CO) can be readily differentiated. CO – cortex; OSOM – outer stripe outer medulla; ISOM – inner stripe outer medulla; IM – inner medulla.
Figure 7.
Comparison of Histological Slices of Clamped Kidney.
(a) PAS histological slice of the clamped kidney. (b) HE-stained histological slice of the clamped kidney, with a similar slice of the phase-contrast volume (c). For both histology slices a respective zoom view of the inner medulla is given. Scarring and beginning tubular atrophy as well proteinaceous casts could be detected correlating with increasing medullary density in PCI.