Contrast Solution Properties and Scan Parameters Influence the Apparent Diffusivity of Computed Tomography Contrast Agents in Articular Cartilage

ABSTRACTThe inability to detect early degenerative changes to the articular cartilage surface that commonly precede bulk osteoarthritic degradation is an obstacle to early disease detection for research or clinical diagnosis. Leveraging a known artifact that blurs tissue boundaries in clinical arthrograms, contrast agent diffusivity can be derived from computed tomography arthrography (CTa) scans. We combined experimental and computational approaches to study protocol variations that may alter the CTa-derived apparent diffusivity. In experimental studies on bovine cartilage explants, we examined how contrast agent dilution and transport direction (absorption vs. desorption) influence the apparent diffusivity of untreated and enzymatically digested cartilage. Using multiphysics simulations, we examined mechanisms underlying experimental observations and the effects of image resolution, scan interval and early scan termination. The apparent diffusivity during absorption decreased with increasing contrast agent concentration by an amount similar to the increase induced by tissue digestion. Models indicated that osmotically induced fluid efflux strongly contributed to the concentration effect. Simulated changes to spatial resolution, scan spacing and total scan time all influenced the apparent diffusivity, indicating the importance of consistent protocols. With careful control of imaging protocols and interpretations guided by transport models, CTa-derived diffusivity offers promise as a biomarker for early degenerative changes.

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Quantitative dual contrast photon-counting computed tomography for assessment of articular cartilage health

Scientific Reports ◽

10.1038/s41598-021-84800-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Petri Paakkari ◽

Satu I. Inkinen ◽

Miitu K. M. Honkanen ◽

Mithilesh Prakash ◽

Rubina Shaikh ◽

...

Keyword(s):

Computed Tomography ◽

Articular Cartilage ◽

Contrast Agent ◽

Contrast Agents ◽

Photon Counting ◽

Spectral Imaging ◽

Ct Scanning ◽

Photon Counting Detector ◽

Tissue Contrast ◽

Reference Parameters

AbstractPhoton-counting detector computed tomography (PCD-CT) is a modern spectral imaging technique utilizing photon-counting detectors (PCDs). PCDs detect individual photons and classify them into fixed energy bins, thus enabling energy selective imaging, contrary to energy integrating detectors that detects and sums the total energy from all photons during acquisition. The structure and composition of the articular cartilage cannot be detected with native CT imaging but can be assessed using contrast-enhancement. Spectral imaging allows simultaneous decomposition of multiple contrast agents, which can be used to target and highlight discrete cartilage properties. Here we report, for the first time, the use of PCD-CT to quantify a cationic iodinated CA4+ (targeting proteoglycans) and a non-ionic gadolinium-based gadoteridol (reflecting water content) contrast agents inside human osteochondral tissue (n = 53). We performed PCD-CT scanning at diffusion equilibrium and compared the results against reference data of biomechanical and optical density measurements, and Mankin scoring. PCD-CT enables simultaneous quantification of the two contrast agent concentrations inside cartilage and the results correlate with the structural and functional reference parameters. With improved soft tissue contrast and assessment of proteoglycan and water contents, PCD-CT with the dual contrast agent method is of potential use for the detection and monitoring of osteoarthritis.

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Gold-coated plant virus as computed tomography imaging contrast agent

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.10.195 ◽

2019 ◽

Vol 10 ◽

pp. 1983-1993 ◽

Cited By ~ 2

Author(s):

Alaa A A Aljabali ◽

Mazhar S Al Zoubi ◽

Khalid M Al-Batanyeh ◽

Ali Al-Radaideh ◽

Mohammad A Obeid ◽

...

Keyword(s):

Computed Tomography ◽

Contrast Agent ◽

Low Cost ◽

Cell Types ◽

Specific Cell ◽

Scan Time ◽

Ct Contrast Agent ◽

Potential Applications ◽

Resolution Imaging

Chemical modification of the surface of viruses, both the interior and the exterior, imparts new functionalities, that have potential applications in nanomedicine. In this study, we developed novel virus-based nanomaterials as a contrast agent for computed tomography (CT) imaging in vitro. The gold-coated cowpea mosaic virus (Au-CPMV) particles were generated by the electrostatic adsorption of positively charged electrolyte on the virus capsid with the subsequent incubation and reduction of anionic gold complexes. Au-CPMV particles as a CT contrast agent offer a fast scan time (less than 2 min), low cost, and biocompatibility and allow for high-resolution imaging with ca. 150 Hounsfield units (HU). The Au-CPMV surface was further modified allowing for the incorporation of targeting molecules of specific cell types.

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Effect of Contrast Agent Charge on Visualization of Articular Cartilage Using Computed Tomography: Exploiting Electrostatic Interactions for Improved Sensitivity

Journal of the American Chemical Society ◽

10.1021/ja9053306 ◽

2009 ◽

Vol 131 (37) ◽

pp. 13234-13235 ◽

Cited By ~ 68

Author(s):

Neel S. Joshi ◽

Prashant N. Bansal ◽

Rachel C. Stewart ◽

Brian D. Snyder ◽

Mark W. Grinstaff

Keyword(s):

Computed Tomography ◽

Articular Cartilage ◽

Contrast Agent ◽

Electrostatic Interactions

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Faculty Opinions recommendation of Effect of contrast agent charge on visualization of articular cartilage using computed tomography: exploiting electrostatic interactions for improved sensitivity.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1166143.627060 ◽

2009 ◽

Author(s):

Ross Weatherman

Keyword(s):

Computed Tomography ◽

Articular Cartilage ◽

Contrast Agent ◽

Electrostatic Interactions

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Computed tomography detects changes in contrast agent diffusion after collagen cross-linking typical to natural aging of articular cartilage

Osteoarthritis and Cartilage ◽

10.1016/j.joca.2011.07.008 ◽

2011 ◽

Vol 19 (10) ◽

pp. 1190-1198 ◽

Cited By ~ 40

Author(s):

H.T. Kokkonen ◽

J. Mäkelä ◽

K.A.M. Kulmala ◽

L. Rieppo ◽

J.S. Jurvelin ◽

...

Keyword(s):

Computed Tomography ◽

Articular Cartilage ◽

Contrast Agent ◽

Natural Aging ◽

Cross Linking ◽

Collagen Cross Linking

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Feasibility and Merits of Performing Preclinical Imaging on Clinical Radiology and Nuclear Medicine Systems

International Journal of Molecular Imaging ◽

10.1155/2013/923823 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Mehmet Bilgen

Keyword(s):

Computed Tomography ◽

Experimental Studies ◽

Vital Signs ◽

Cost Effective ◽

Laboratory Animals ◽

Preclinical Imaging ◽

Scan Time ◽

Positron Emission ◽

Magnetic Resonance Imaging Mri ◽

Clinical Systems

Aim. Researchers have limited access to systems dedicated to imaging small laboratory animals. This paper aims to investigate the feasibility and merits of performing preclinical imaging on clinical systems. Materials and Methods. Scans were performed on rat and mouse models of diseases or injuries on four radiology systems, tomosynthesis, computed tomography (CT), positron emission tomography/computed tomography (PET-CT), and Magnetic Resonance Imaging (MRI), based on the availability at the author’s institute. Results. Tomosysthesis delineated soft tissue anatomy and hard tissue structure with superb contrast and spatial resolution at minimal scan time and effort. CT allowed high resolution volumetric visualization of bones. Molecular imaging with PET was useful for detecting cancerous tissue in mouse but at the expense of poor resolution. MRI depicted abnormal or intervened tissue at quality and resolution sufficient for experimental studies. The paper discussed limitations of the clinical systems in preclinical imaging as well as challenges regarding the need of additional gadgets, modifications, or upgrades required for longitudinally scanning animals under anesthesia while monitoring their vital signs. Conclusion. Clinical imaging technologies can potentially make cost-effective and efficient contributions to preclinical efforts in obtaining anatomical, structural, and functional information from the underlying tissue while minimally compromising the data quality in certain situations.

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Diagnostic Yield of Micro-Computed Tomography (micro-CT) Versus Histopathology of a Canine Oral Fibrosarcoma

Journal of Veterinary Dentistry ◽

10.1177/0898756420926519 ◽

2020 ◽

Vol 37 (1) ◽

pp. 14-21

Author(s):

Matthias C. Eberspächer-Schweda ◽

Kira Schmitt ◽

Stephan Handschuh ◽

Andrea Fuchs-Baumgartinger ◽

Alexander M. Reiter

Keyword(s):

Computed Tomography ◽

Contrast Agent ◽

Tumor Volume ◽

Ct Imaging ◽

Image Resolution ◽

Surrounding Tissue ◽

Histopathological Diagnosis ◽

Micro Ct ◽

Micro Computed Tomography ◽

Tumor Margins

Micro-computed tomography (micro-CT) imaging currently gains increased interest in human as well as veterinary medicine. The ability to image 3-dimensional (3D) biopsy specimens nondestructively down to 1 µm spatial resolution makes it a promising tool for microscopic tissue evaluation in addition to histopathology. Visualizing tumor margins and calculating tumor load on 3D reconstructions may also enhance oncological therapies. The objective of this study was to describe the workflow from tumor resection to histopathological diagnosis, using both routine hematoxylin-eosin (HE)-stained sections and micro-CT tomograms on a stage II oral fibrosarcoma in a 7-year-old Hovawart dog. The maxillectomy specimen was fixed with formalin and stained with an X-ray dense soft tissue contrast agent. Micro-CT imaging was done using an ex vivo specimen micro-CT device. Tumor margins could not be exactly determined on micro-CT tomograms due to limited image resolution and contrast. Histopathology was performed after washing out the contrast agent. It showed neoplastic cells infiltrating the surrounding tissue further than assumed from micro-CT images. A total tumor volume of 10.3 cm3 could be calculated based on correlating micro-CT tomograms with HE-stained sections. This correlative approach may be of particular interest for oncological therapy. More than that, micro-CT imaging technology supported histopathology by means of 3D orientation and selection of slices to be cut on determining tumor margins. In this clinical case report, micro-CT imaging did not provide unambiguous clinical evidence for oncological decision-making, but it showed potential to support histopathology and calculate tumor volume for further clinical use.

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