Synchrotron-based phase-contrast micro-CT as a tool for understanding pulmonary vascular pathobiology and the 3-D microanatomy of alveolar capillary dysplasia

• Published in: American journal of physiology. Lung cellular and molecular physiology Vol. 318; no. 1; pp. L65 - L75
• Main Authors: Norvik, Christian, Westöö, Christian Karl, Peruzzi, Niccolò, Lovric, Goran, van der Have, Oscar, Mokso, Rajmund, Jeremiasen, Ida, Brunnström, Hans, Galambos, Csaba, Bech, Martin, Tran-Lundmark, Karin
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.01.2020
• Subjects: Algorithms; alveolar capillary dysplasia; Alveoli; Annan fysik; Arteries; Attenuation; Basic Medicine; Blood vessels; Bronchi - pathology; Computed tomography; Dyes; Dysplasia; Field of view; Fysik; Fysiologi; Histology; Humans; Hypertension; Hypertension, Pulmonary - pathology; Image acquisition; Image processing; Image resolution; Image segmentation; imaging; Imaging, Three-Dimensional - methods; Immunohistochemistry; Infant, Newborn; Light sources; lung; Lung - pathology; Lungs; Medical and Health Sciences; Medical imaging; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Microscopy, Phase-Contrast - methods; Microvasculature; Natural Sciences; Naturvetenskap; Nondestructive testing; Other Physics Topics; Paraffin; Paraffins; Persistent Fetal Circulation Syndrome - pathology; Phase retrieval; Physical Sciences; Physiology; Pulmonary Alveoli - abnormalities; Pulmonary Alveoli - pathology; pulmonary hypertension; Pulmonary Veins - pathology; Spatial resolution; synchrotron; Synchrotrons; Tissues; tomography; Veins; Veins & arteries; X-Ray Microtomography - methods; lung; alveolar capillary dysplasia; synchrotron; imaging; pulmonary hypertension; tomography
• ISSN: 1040-0605; 1522-1504; 1522-1504
• DOI: 10.1152/ajplung.00103.2019

This study aimed to explore the value of synchrotron-based phase-contrast microcomputed tomography (micro-CT) in pulmonary vascular pathobiology. The microanatomy of the lung is complex with intricate branching patterns. Tissue sections are therefore difficult to interpret. Recruited intrapulmonary bronchopulmonary anastomoses (IBAs) have been described in several forms of pulmonary hypertension, including alveolar capillary dysplasia with misaligned pulmonary veins (ACD/MPV). Here, we examine paraffin-embedded tissue using this nondestructive method for high-resolution three-dimensional imaging. Blocks of healthy and ACD/MPV lung tissue were used. Pulmonary and bronchial arteries in the ACD/MPV block had been preinjected with dye. One section per block was stained, and areas of interest were marked to allow precise beam-alignment during image acquisition at the X02DA TOMCAT beamline (Swiss Light Source). A ×4 magnifying objective coupled to a 20-µm thick scintillating material and a sCMOS detector yielded the best trade-off between spatial resolution and field-of-view. A phase retrieval algorithm was applied and virtual tomographic slices and video clips of the imaged volumes were produced. Dye injections generated a distinct attenuation difference between vessels and surrounding tissue, facilitating segmentation and three-dimensional rendering. Histology and immunohistochemistry post-imaging offered complementary information. IBAs were confirmed in ACD/MPV, and the MPVs were positioned like bronchial veins/venules. We demonstrate the advantages of using synchrotron-based phase-contrast micro-CT for three-dimensional characterization of pulmonary microvascular anatomy in paraffin-embedded tissue. Vascular dye injections add additional value. We confirm intrapulmonary shunting in ACD/MPV and provide support for the hypothesis that MPVs are dilated bronchial veins/venules.