Micro-computed tomography for the quantification of blocked fibers in hemodialyzers

Floris Vanommeslaeghe, Wim Van Biesen, Manuel Dierick, Matthieu Boone, Annemieke Dhondt, Sunny Eloot, Floris Vanommeslaeghe, Wim Van Biesen, Manuel Dierick, Matthieu Boone, Annemieke Dhondt, Sunny Eloot

Abstract

A novel technique based on micro-CT scanning is developed to quantify coagulation in fibers of hemodialyzers. This objectivation is needed to allow accurate assessment of thrombogenicity of dialyzers used during hemodialysis, for example when comparing different strategies to avoid coagulation and/or fiber blocking. The protocol allowed imaging at a resolution of 25 µm, making it possible to count the open, non-coagulated fibers in a non-invasive way. In 3 fresh, non-used FX600 hemodialyzers, patent fiber counts were extremely consistent (10748 ± 2). To illustrate the potential of this technique, different dialysis parameters currently used as surrogates for fiber blocking were evaluated during 20 hemodialysis sessions. After dialysis, the FX600 dialyzers were visually scored for clotting, dried and subsequently weighed and scanned. The number of patent fibers (10003 [8763,10330], range 534-10692) did not correlate with any of the recorded surrogate parameters. Micro-CT scanning is a feasible, objective, non-invasive, accurate and reproducible tool for quantification of the degree of fiber blocking in a hemodialyzer after use, making it a potential gold standard for use in studies on fiber blocking during renal replacement therapies.

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Representative CT images of dialyzer cross-sections (reference slice) showing different levels of coagulation.
Figure 2
Figure 2
Associations between the number of fibers and a selection of different registered parameters: dialyzer dry mass (panel A), visual scoring of dialyzer (panel B), post minus pre dialysis TMP (panel C), and pre minus post dialysis OCM (panel D).
Figure 3
Figure 3
CT images of cross-sections in the same used dialyzer halfway the dialyzer (left panel) and at the central cross-section in the outlet potting (right panel). Central fibers are open and peripheral fibers are blocked. Sections in the potting offer optimal visualization of air inflated open fibers, appearing as black dots.
Figure 4
Figure 4
CT image of cross-section (panel A). Optimization of image brightness and selection of the region of interest (ROI) bordering the entire fiber bundle (panel B). Zoomed inset of counted fibers (panel C).

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