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Author: Tim Johann4
Guided interactive image segmentation using machine learning and color based data set clustering

Abstract

Not specified

Authors: Adrian Friebel, Tim Johann, Dirk Drasdo, Stefan Hoehme

Date Published: 18th May 2020

Publication Type: Misc

A quantitative high-resolution computational mechanics cell model for growing and regenerating tissues

Abstract

Not specified

Authors: Paul Van Liedekerke, Johannes Neitsch, Tim Johann, Enrico Warmt, Ismael Gonzàlez-Valverde, Stefan Hoehme, Steffen Grosser, Josef Kaes, Dirk Drasdo

Date Published: 1st Feb 2020

Publication Type: Journal

Quantitative analysis of hepatic macro- and microvascular alterations during cirrhogenesis in the rat.

Abstract (Expand)

Cirrhosis represents the end-stage of any persistent chronically active liver disease. It is characterized by the complete replacement of normal liver tissue by fibrosis, regenerative nodules, and … complete fibrotic vascularized septa. The resulting angioarchitectural distortion contributes to an increasing intrahepatic vascular resistance, impeding liver perfusion and leading to portal hypertension. To date, knowledge on the dynamically evolving pathological changes of the hepatic vasculature during cirrhogenesis remains limited. More specifically, detailed anatomical data on the vascular adaptations during disease development is lacking. To address this need, we studied the 3D architecture of the hepatic vasculature during induction of cirrhogenesis in a rat model. Cirrhosis was chemically induced with thioacetamide (TAA). At predefined time points, the hepatic vasculature was fixed and visualized using a combination of vascular corrosion casting and deep tissue microscopy. Three-dimensional reconstruction and data-fitting enabled cirrhogenic features to extracted at multiple scales, portraying the impact of cirrhosis on the hepatic vasculature. At the macrolevel, we noticed that regenerative nodules severely compressed pliant venous vessels from 12 weeks of TAA intoxication onwards. Especially hepatic veins were highly affected by this compression, with collapsed vessel segments severely reducing perfusion capabilities. At the microlevel, we discovered zone-specific sinusoidal degeneration, with sinusoids located near the surface being more affected than those in the middle of a liver lobe. Our data shed light on and quantify the evolving angioarchitecture during cirrhogenesis. These findings may prove helpful for future targeted invasive interventions.

Authors: G. Peeters, C. Debbaut, A. Friebel, P. Cornillie, W. H. De Vos, K. Favere, I. Vander Elst, T. Vandecasteele, T. Johann, L. Van Hoorebeke, D. Monbaliu, D. Drasdo, S. Hoehme, W. Laleman, P. Segers

Date Published: 4th Dec 2017

Publication Type: Not specified

A multilevel framework to reconstruct anatomical 3D models of the hepatic vasculature in rat livers

Abstract (Expand)

The intricate (micro)vascular architecture of the liver has not yet been fully unravelled. Although current models are often idealized simplifications of the complex anatomical reality, correct … morphological information is instrumental for scientific and clinical purposes. Previously, both vascular corrosion casting (VCC) and immunohistochemistry (IHC) have been separately used to study the hepatic vasculature. Nevertheless, these techniques still face a number of challenges such as dual casting in VCC and limited imaging depths for IHC. We have optimized both techniques and combined their complementary strengths to develop a framework for multilevel reconstruction of the hepatic circulation in the rat. The VCC and micro-CT scanning protocol was improved by enabling dual casting, optimizing the contrast agent concentration, and adjusting the viscosity of the resin (PU4ii). IHC was improved with an optimized clearing technique (CUBIC) that extended the imaging depth for confocal microscopy more than five-fold. Using in-house developed software (DeLiver), the vascular network - in both VCC and IHC datasets - was automatically segmented and/or morphologically analysed. Our methodological framework allows 3D reconstruction and quantification of the hepatic circulation, ranging from the major blood vessels down to the intertwined and interconnected sinusoids. We believe that the presented framework will have value beyond studies of the liver, and will facilitate a better understanding of various parenchymal organs in general, in physiological and pathological circumstances.

Authors: Geert Peeters, Charlotte Debbaut, Wim Laleman, Adrian Friebel, Diethard Monbaliu, Ingrid Vander Elst, Jan R Detrez, Tim Vandecasteele, Tim Johann, Thomas De Schryver, Luc Van Hoorebeke, Kasper Favere, Jonas Verbeke, Dirk Drasdo, Stefan Hoehme, Patrick Segers, Pieter Cornillie, Winnok H De Vos

Date Published: 28th Dec 2016

Publication Type: Not specified

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