scholarly journals Soft tissue discrimination with contrast agents using micro-CT scanning

2020 ◽  
Vol 144 (1) ◽  
Author(s):  
Emilie Descamps ◽  
Alicja Sochacka ◽  
Barbara De Kegel ◽  
Denis Van Loo ◽  
Luc Van Hoorebeke ◽  
...  

The use of high resolution, three-dimensional visualization has been receiving growing interest within life sciences, with non-invasive imaging tools becoming more readily accessible. Although initially useful for visualizing mineralized tissues, recent developments are promising for studying soft tissues as well. Especially for micro-CT scanning, several X-ray contrast enhancers are performant in sufficiently contrasting soft tissue organ systems by a different attenuation strength of X-rays. Overall visualization of soft tissue organs has proven to be possible, although the tissue-specific capacities of these enhancers remain unclear. In this study, we tested several contrast agents for their usefulness to discriminate between tissue types and organs, using three model organisms (mouse, zebrafish and Xenopus). Specimens were stained with osmium tetroxide (OsO4), phosphomolybdic acid (PMA) and phosphotungstic acid (PTA), and were scanned using high resolution microtomography. The contrasting potentials between tissue types and organs are described based on volume renderings and virtual sections. In general, PTA and PMA appeared to allow better discrimination. Especially epithelial structures, cell-dense brain regions, liver, lung and blood could be easily distinguished. The PMA yielded the best results, allowing discrimination even at the level of cell layers. Our results show that those staining techniques combined with micro-CT imaging have good potential for use in future research in life sciences.

Author(s):  
Sebastian Halm ◽  
David Haberthür ◽  
Elisabeth Eppler ◽  
Valentin Djonov ◽  
Andreas Arnold

Abstract Introduction This pilot study explores whether a human Thiel-embalmed temporal bone is suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and whether solid iodine-staining improves visualization and facilitates segmentation of middle ear structures. Methods A temporal bone was used to verify the accuracy of the imaging by first digitally measuring the stapes on the tomography images and then physically under the microscope after removal from the temporal bone. All measurements were compared with literature values. The contralateral temporal bone was used to evaluate segmentation and three-dimensional (3D) modeling after iodine staining and micro-CT scanning. Results The digital and physical stapes measurements differed by 0.01–0.17 mm or 1–19%, respectively, but correlated well with the literature values. Soft tissue structures were visible in the unstained scan. However, iodine staining increased the contrast-to-noise ratio by a factor of 3.7 on average. The 3D model depicts all ossicles and soft tissue structures in detail, including the chorda tympani, which was not visible in the unstained scan. Conclusions Micro-CT imaging of a Thiel-embalmed temporal bone accurately represented the entire anatomy. Iodine staining considerably increased the contrast of soft tissues, simplified segmentation and enabled detailed 3D modeling of the middle ear.


2021 ◽  
Author(s):  
Eva Chatzinikolaou ◽  
Kleoniki Keklikoglou

Micro-computed tomography (micro-CT) is a high-resolution 3D-imaging technique which is now increasingly applied in biological studies focusing on taxonomy and functional morphology. The creation of virtual representations of specimens can increase availability of otherwise underexploited and inaccessible samples. This protocol aims to standardise micro-CT scanning procedures for embryos and juveniles of the marine gastropod species Hexaplex trunculus.


Author(s):  
Stephanie Panzer ◽  
Patrizia Pernter ◽  
Dario Piombino-Mascali ◽  
Rimantas Jankauskas ◽  
Stephanie Zesch ◽  
...  

Purpose Soft tissues make a skeleton into a mummy and they allow for a diagnosis beyond osteology. Following the approach of structured reporting in clinical radiology, a recently developed checklist was used to evaluate the soft tissue preservation status of the Tyrolean Iceman using computed tomography (CT). The purpose of this study was to apply the “Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies” to the Tyrolean Iceman, and to compare the Iceman’s soft tissue preservation score to the scores calculated for other mummies. Materials and Methods A whole-body (CT) (SOMATOM Definition Flash, Siemens, Forchheim, Germany) consisting of five scans, performed in January 2013 in the Department of Radiodiagnostics, Central Hospital, Bolzano, was used (slice thickness 0.6 mm; kilovolt ranging from 80 to 140). For standardized evaluation the “CT Checklist and Scoring System for the Assessment of Soft Tissue Preservation in Human Mummies” was used. Results All checkpoints under category “A. Soft Tissues of Head and Musculoskeletal System” and more than half in category “B. Organs and Organ Systems” were observed. The scoring system accounted for a total score of 153 (out of 200). The comparison of the scores between the Iceman and three mummy collections from Vilnius, Lithuania, and Palermo, Sicily, as well as one Egyptian mummy resulted in overall higher soft tissue preservation scores for the Iceman. Conclusion Application of the checklist allowed for standardized assessment and documentation of the Iceman’s soft tissue preservation status. The scoring system allowed for a quantitative comparison between the Iceman and other mummies. The Iceman showed remarkable soft tissue preservation. Key Points  Citation Format


2006 ◽  
Vol 126 (5) ◽  
pp. 467-474 ◽  
Author(s):  
A. Postnov ◽  
A. Zarowski ◽  
N. De Clerck ◽  
F. Vanpoucke ◽  
F.E. Offeciers ◽  
...  

Author(s):  
Thomas Valenzuela ◽  
Jorge Zhingre Sanchez ◽  
Mikayle Holm ◽  
Tinen Iles ◽  
Paul Iaizzo

Abstract There are few medical devices currently utilized that have not had, at the very least, a second iteration. Medical device companies continually strive to improve their product to make it the best on the market. Medical devices are often optimized by defining the size of the device, making it more efficient and/or improving the device to tissue interface. Using the capabilities of the Visible Heart® Laboratories various cardiac devices can be implanted in reanimated swine and human hearts for the assessment of the various aforementioned parameters. After the implantation of these devices and assessment in functional anatomies, specimens were perfusion-fixed and then a micro-CT scanner was utilized to take high-resolution scans of the resultant device and tissue interfaces. These scans are used to generate high-resolution (∼20 microns) 3D models of the numerous implanted devices, measurement analyses, device simulations, and the creation of virtual reality scenes. All can then be used for detailed visual analyses. These abilities to render high-resolution models will allow medical device designers to closely evaluate their designs, in order to optimize their next iterations.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charmainne Cruje ◽  
P. Joy Dunmore-Buyze ◽  
Eric Grolman ◽  
David W. Holdsworth ◽  
Elizabeth R. Gillies ◽  
...  

AbstractVascular research is largely performed in rodents with the goal of developing treatments for human disease. Micro-computed tomography (micro-CT) provides non-destructive three-dimensional imaging that can be used to study the vasculature of rodents. However, to distinguish vasculature from other soft tissues, long-circulating contrast agents are required. In this study, we demonstrated that poly(ethylene glycol) (PEG)-coated gadolinium nanoparticles can be used as a vascular contrast agent in micro-CT. The coated particles could be lyophilized and then redispersed in an aqueous solution to achieve 100 mg/mL of gadolinium. After an intravenous injection of the contrast agent into mice, micro-CT scans showed blood pool contrast enhancements of at least 200 HU for 30 min. Imaging and quantitative analysis of gadolinium in tissues showed the presence of contrast agent in clearance organs including the liver and spleen and very low amounts in other organs. In vitro cell culture experiments, subcutaneous injections, and analysis of mouse body weight suggested that the agents exhibited low toxicity. Histological analysis of tissues 5 days after injection of the contrast agent showed cytotoxicity in the spleen, but no abnormalities were observed in the liver, lungs, kidneys, and bladder.


2022 ◽  
Vol 327 ◽  
pp. 33-44
Author(s):  
Stephen P. Midson

Porosity is one of the main defects that limits the performance of castings. Porosity in aluminum castings can originate from several sources, including the volumetric shrinkage occurring during solidification, the precipitation of dissolved hydrogen, and entrapment of gasses such as air, boiling water, vaporized lubricants, etc. Traditional methods of identifying and measuring porosity in castings include 2D x-rays, sectioning and polishing, and Archimedes density measurements, but none of these provide a satisfactory quantitative estimate of the size, total volume and distribution of the pores. X-ray CT scanning is a relatively new method that generates not only a 3-dimensional view of the size and distribution of the pores, but can also provide quantitative information of the volume, surface area, size, shape and position of each pore within a casting. Micro-CT scanning is a specialized sub-category of CT scanning, which provides excellent resolution of fine porosity (a resolution limit of 4 microns in one of the case-stores presented in this paper), but it should be noted that the resolution limit in CT scanning techniques is related to sample size. This paper describes results from micro-CT scanning studies of two high pressure die castings and a semi-solid casting, and provides quantitative data on the total porosity content, and the porosity distribution. The paper will also demonstrate the capabilities of the micro-CT scanning process to provide a quantitative comparison of the porosity content in these different types of aluminum castings.


Author(s):  
Ponky Firer ◽  
Brad Gelbart

IntroductionPatient satisfaction, after mechanically aligned Total Knee Arthroplasty (TKA) is only 80%-85%. There is an inabilty to consistently get perfect soft tissue balance with this technique. It is postulated that soft tissue balance within 2° can be achieved by the boney cuts (Bone Balancing) without soft tissue releases, accepting whatever coronal mechanical alignment (CMA) this produces; that the alignment produced would be similar to natural (constitutional) alignment and that balanced knees would improve patient satisfaction.MethodsWe report on 914 consecutive TKAs using Bone Balancing: the femoral rotation for the flexion gap; the distal femoral cut and valgus angle for the extension gap are adjusted to give equal gap sizes with soft tissue balanced within 2° of medio-lateral laxity. Long leg X-rays were used to measure post-operative coronal alignment. Satisfaction beyond 1 year post operation was assessed by an independent researcher, using a question on satisfaction and a VAS score.Results782(85.5%) TKAs with satisfactory x-rays were available at 2-7 years follow up. Their CMA had a similar distribution profile to reported natural alignment studies. Of these, 672 (86%) had a CMA of 0°±3° (’aligned' group). Overall patient satisfaction was 92.8%, with satisfied patients having a mean (range) VAS score of 9.53 (7.3-10.0) and the dissatisfied patients 3.78 (0.0-6.3) (p<0.0001). There was no difference in satisfaction between ’aligned' knees (92.7%) and those ’outliers', whose CMA was >±3° (93.6%) (p=0.853). All balance measurements were within 3° with 92.2% being ≤2°. Gap size difference between extension and 90° flexion was ≤2mm in 98.7% of cases. Midflexion (45° flexion) balance was within 3° in all cases and the gap size difference was ≤2mm in 89%.ConclusionBalancing by bone cuts is able to achieve accurately balanced soft tissues without the need for soft tissue releases. The coronal alignment profile produced matches that of the normal population. This technique improves satisfaction compared to the literature for mechanically aligned TKAs. Acurate and measured soft tissue balancing needs further consideration in TKAs.Level of EvidenceLevel IV.


2017 ◽  
Vol 113 (11/12) ◽  
Author(s):  
Jacqueline S. Smilg

Computed tomography (CT) imaging of fossils has revolutionised the field of palaeontology, allowing researchers to gain a better understanding of fossil anatomy, preservation and conservation. Micro focus X-ray computed tomography (μXCT) has been far more extensively used for these purposes than medical CT (XCT) – mostly because of the exquisite detail that the μXCT scanning modality, using slices of micron thicknesses, can produce. High energy X-rays can potentially penetrate breccia more effectively than lower energy beams. This study demonstrates that lower energy beams produce superior images for prioritising breccia for preparation. Additionally, XCT scanners are numerous, accessible, fast and relatively cost-effective when compared to μXCT scanners – the latter are not freely available, scanning times are much longer and there are significant limitations on the size and weight of scannable objects. Breccia blocks from Malapa were scanned at high and lower energy and images were analysed for image quality, artifact and certainty of diagnosis. Results show that lower energy images are deemed superior to higher energy images for this particular application. This finding, taken together with the limitations associated with the use of μXCT for the imaging of the large breccia from Malapa, shows that XCT is the better modality for this specific application. The ability to choose fossil-bearing breccia, ahead of manual mechanical preparation by laboratory technicians, would allow for the optimal use of limited resources, manual preparatory skills as well as the curtailment of costs.


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