X-ray-based virtual slicing of TB-infected lungs

Abstract

Hollow organs such as the lungs pose a considerable challenge for post-mortem imaging in preclinical research owing to their extremely low contrast and high structural complexity. The aim of our study was to enhance the contrast of tuberculosis lesions for their stratification by 3D x-ray–based virtual slicing. Organ samples were taken from five control and five tuberculosis-infected mice. Micro-Computed Tomography (CT) scans of the subjects were acquired in vivo (without contrast agent) and post-mortem (with contrast agent). The proposed contrast-enhancing technique consists of x-ray contrast agent uptake (silver nitrate and iodine) by immersion. To create the histology ground-truth, the CT scan of the paraffin block guided the sectioning towards specific planes of interest. The digitalized histological slides reveal the presence, extent, and appearance of the contrast agents in lung structures and organized aggregates of immune cells. These findings correlate with the contrast-enhanced micro-CT slice. The abnormal densities in the lungs due to tuberculosis disease are concentrated in the right tail of the lung intensity histograms. The increase in the width of the right tail (~376%) indicates a contrast enhancement of the details of the abnormal densities. Postmortem contrast agents enhance the x-ray attenuation in tuberculosis lesions to allow 3D visualization by polychromatic x-ray CT, providing an advantageous tool for virtual slicing of whole lungs. The proposed contrast-enhancing technique combined with computational methods and the diverse micro-CT modalities will open the doors to the stratification of lesion types associated with infectious diseases.

Molecular Imaging of Pulmonary Tuberculosis in an Ex-Vivo Mouse Model Using Spectral Photon-Counting Computed Tomography and Micro-CT

“…Histology provides the ground truth to check for correlation between images and histological cuts. The methods we followed for guiding histology are well established [28,30,35]. The results of the histological images confirmed lesion location.…”

“…Paraffin blocks were left to cool and harden for 24 hrs before imaging. The purpose of paraffin fixing was to enable a direct comparison between micro-CT and spectral CT images [30].…”

“…7 displays three-dimensional (3D) data obtained by the micro-CT (top) and data obtained by the spectral CT (bottom). There was some collapse of lung tissue due to the paraffin fixing process [30]. The threshold computed for tissue analysis was applied to the iodine material dataset of the healthy and TB-infected lung images.…”

The Value of Micro-CT in the Diagnosis of Lung Carcinoma: A Radio-Histopathological Perspective

“…According to this study, thickened alveolar walls corresponded to adenocarcinoma with lepidic growth pattern, and thin alveolar walls corresponded to normal lung [25]. Virtual histological images can be obtained via micro-CT, with the application of special ex vivo protocols [31,[80][81][82][83]. There are a few studies on human tissues showing that it is also possible to obtain digitally colored images comparable to HE-stained slides from routinely prepared FFPE tissue blocks [24,34,84] (Figure 2A inset).…”

Morphological Characteristics of Lungs in Laboratory Balb/C Mice

“…Ми проаналізували 68 джерел бази даних PubMed за ключовими словами «mouse lung necropsy (некропсія легень миші)» за останні 5 років, серед яких виявили 37 відповідних робіт, які включали морфологічне дослідження легень мишей, і 15 публікації в яких описано інфузію забуференим нейтральним формаліном при некропсії та фіксації легень [2,8,10,18,19,22,34,35,38,50,41,42,43,51,52], та 4 роботи де використано перфузію крізь лівий шлуночок серця або судини для збереження об'єму легень [4,5,10,40]. Отже, тільки у 51% робіт зазначено конкретну процедуру по попередження колапсу легень.…”