Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
Geosciences, Museums Victoria, Melbourne, Victoria, Australia.
PeerJ. 2024 Sep 5;12:e17919. doi: 10.7717/peerj.17919. eCollection 2024.
Diffusible iodine-based contrast-enhanced computed tomography (diceCT) is an increasingly used digital complement, supplement, or alternative to traditional dissection-based anatomical research. The diceCT protocol, which has evolved and expanded over the past decade, employs passive diffusion of Lugol's iodine (KI) to increase soft tissue radiodensity and improve structure contrast in the CT or microCT imaging of specimens. The development and application of diceCT has focused largely on specimens under 1 kg, and the varying reporting of methods on studies of both small and large specimens has initiated, but not yet established, an effective diceCT protocol for larger specimens based on monitored experiments of several fundamental variables (., Lugol's iodine concentration, duration, and impacts of Lugol's iodine on tissues). In this study, we have experimentally assessed the efficacy of diceCT protocols for imaging whole-body specimens of the 1-4.5 kg Australian brushtail possum () using sequential CT imaging assessment across experimental conditions. We assessed the impact of varying Lugol's iodine concentration, the presence/absence of skin, solution volume and agitation on tissue radiodensity changes through weekly CT-based monitoring of tissue radiodensities over an 8-week experimental period. We have also quantified tissue volumetric changes across our experiment to assess the impact of diceCT applications on subsequent analyses of imaging datasets. Our results indicate that substantial changes in both soft-tissue radiodensity and soft-tissue volume occur within the first 28 days of Lugol's iodine treatment, followed by a slower rate of progressive soft-tissue radiodensity and volume changes across the experiment duration. Our results demonstrate the negligible benefit of skinning larger specimens to improve solution diffusion, and document significant soft-tissue volumetric changes with high concentration solutions (., 10%) and long-duration exposure (., beyond 5 weeks) that should guide individual diceCT protocol design and/or quantification and analysis for mammal specimens above 1 kg.
基于弥散碘的对比增强计算机断层扫描（diceCT）是一种越来越常用的数字补充、补充或替代传统解剖学研究的方法。diceCT 协议在过去十年中不断发展和扩展，利用卢戈氏碘（KI）的被动扩散来增加软组织的放射密度，并提高标本的 CT 或 microCT 成像中的结构对比度。diceCT 的开发和应用主要集中在 1 公斤以下的标本上，对大小标本的研究方法的不同报告已经启动，但尚未基于对几个基本变量（例如卢戈氏碘浓度、持续时间以及卢戈氏碘对组织的影响）的监测实验为较大的标本建立有效的 diceCT 协议。在这项研究中，我们使用跨实验条件的连续 CT 成像评估，实验评估了用于成像 1-4.5 公斤澳大利亚帚尾袋貂（）全身标本的 diceCT 协议的功效。我们通过每周基于 CT 的组织放射密度监测，评估了不同卢戈氏碘浓度、存在/不存在皮肤、溶液体积和搅拌对组织放射密度变化的影响，在 8 周的实验期间。我们还对整个实验进行了组织体积变化的量化，以评估 diceCT 应用对随后的成像数据集分析的影响。我们的结果表明，卢戈氏碘处理后的前 28 天内，软组织放射密度和软组织体积都发生了显著变化，然后在实验持续时间内，软组织放射密度和体积的变化速度较慢。我们的结果表明，对较大的标本进行剥皮以改善溶液扩散几乎没有益处，并记录了高浓度溶液（例如 10%）和长时间暴露（例如超过 5 周）的显著软组织体积变化，这些结果应指导大于 1 公斤的哺乳动物标本的个体 diceCT 协议设计和/或定量和分析。
