Optimal Iodine Staining of Cardiac Tissue for X-Ray Computed Tomography

Abstract

X-ray computed tomography (XCT) has been shown to be an effective imaging technique for a variety of materials. Due to the relatively low differential attenuation of X-rays in biological tissue, a high density contrast agent is often required to obtain optimal contrast. The contrast agent, iodine potassium iodide (), has been used in several biological studies to augment the use of XCT scanning. Recently was used in XCT scans of animal hearts to study cardiac structure and to generate 3D anatomical computer models. However, to date there has been no thorough study into the optimal use of as a contrast agent in cardiac muscle with respect to the staining times required, which has been shown to impact significantly upon the quality of results. In this study we address this issue by systematically scanning samples at various stages of the staining process. To achieve this, mouse hearts were stained for up to 58 hours and scanned at regular intervals of 6–7 hours throughout this process. Optimal staining was found to depend upon the thickness of the tissue; a simple empirical exponential relationship was derived to allow calculation of the required staining time for cardiac samples of an arbitrary size.

Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography

“…Until recently, x-ray tomography has been limited in its ability to reveal features within non-calcified, and hence weakly x-ray absorbing, tissues. Whilst x-ray absorption and therefore contrast can be enhanced using high Z elements 22 difficulties remain with ensuring that these agents: i) penetrate larger tissues, ii) differentiate between tissue components and iii) are compatible with subsequent histological techniques 23 . Alternatively, x-ray phase contrast approaches can enhance contrast in non-calcified tissues including cartilage 24 , tendon 25 , plaque containing blood vessels 26 , coronary artery 27 , ligaments and the intervertebral disc 28 .…”

Optimal Contrast Agent Staining of Ligaments and Tendons for X-Ray Computed Tomography

“…As an example, the line profiles of the PTA-stained LCL are plotted in Fig 2 (note that the vertical axis in this figure shows the normalised intensity; this value is obtained by dividing the observed intensity in a given line profile by the maximum intensity that was recorded across any of the sixty line profiles that were plotted, thus giving a number between 0 and 1). The ligament edge was identified using a three-stage process based on that outlined in [ 16 ]: 1) the line profile was filtered with a Gaussian kernel (σ = 4), 2) the maximum intensity gradient was located, and 3) the edge was defined as the next point towards the sample centre where the absolute value of the intensity gradient was approximately zero (<0.01). The opposing edge was identified as the last point from the sample centre where the absolute value of the intensity gradient was approximately zero before the location of the minimum gradient.…”

“…Butters et al . [ 16 ] investigated the optimal I2KI staining of rat hearts, and Shearer et al . [ 14 ] investigated the optimal I2KI and PTA staining of porcine anterior cruciate ligaments (ACLs) and patellar tendons (PTs) using low concentration contrast agents.…”

X-ray computed tomography in life sciences

“…Mathematical models are being developed to predict the staining uptake within tissues, based on mass transfer theory [49]. However, at present a time-course study is recommended to determine the ideal staining duration of a particular tissue type with a given stain [50].…”