Assessment of candidate elements for development of spectral photon-counting CT specific contrast agents

Kim, Johoon; Bar-Ness, Daniel; Si‐Mohamed, Salim; Coulon, Philippe; Blevis, I.; Douek, Philippe; Cormode, David P.

doi:10.1038/s41598-018-30570-y

Cited by 74 publications

(95 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Tracking therapeutic cells with CT is an emerging field (reviewed in (12)). The main originality of spectral CT compared to other non-spectral X-ray-based approaches (µCT, clinical CT or synchrotron radiation CT (41)) is represented by its specificity with regard to the detection of gold or other elements with K-edge energies in the appropriate range (~40 -100 keV) (42)(43)(44). Pioneering work for the specific imaging of macrophages with SPCCT was published 10 years ago in a mouse model of atherosclerosis (45).…”

Section: Discussionmentioning

confidence: 99%

Multicolor spectral photon counting CT monitors and quantifies therapeutic cells and their encapsulating scaffold in a model of brain damage

Cuccione¹,

Chhour²,

Dumot³

et al. 2020

Nanotheranostics

Self Cite

View full text Add to dashboard Cite

Rationale & aim: Various types of cell therapies are currently under investigation for the treatment of ischemic stroke patients. To bridge the gap between cell administration and therapeutic outcome, there is a need for non-invasive monitoring of these innovative therapeutic approaches. Spectral photon counting computed tomography (SPCCT) is a new imaging modality that may be suitable for cell tracking. SPCCT is the next generation of clinical CT that allows the selective visualization and quantification of multiple contrast agents. The aims of this study are: (i) to demonstrate the feasibility of using SPCCT to longitudinally monitor and quantify therapeutic cells, i.e. bone marrow-derived M2-polarized macrophages transplanted in rats with brain damage; and (ii) to evaluate the potential of this approach to discriminate M2-polarized macrophages from their encapsulating scaffold. Methods: Twenty one rats received an intralesional transplantation of bone marrow-derived M2-polarized macrophages. In the first set of experiments, cells were labeled with gold nanoparticles and tracked for up to two weeks post-injection in a monocolor study via gold K-edge imaging. In the second set of experiments, the same protocol was repeated for a bicolor study, in which the labeled cells are embedded in iodine nanoparticle-labeled scaffold. The amount of gold in the brain was longitudinally quantified using gold K-edge images reconstructed from SPCCT acquisition. Animals were sacrificed at different time points post-injection, and ICP-OES was used to validate the accuracy of gold quantification from SPCCT imaging. Results: The feasibility of therapeutic cell tracking was successfully demonstrated in brain-damaged rats with SPCCT imaging. The imaging modality enabled cell monitoring for up to 2 weeks post-injection, in a specific and quantitative manner. Differentiation of labeled cells and their embedding scaffold was also feasible with SPCCT imaging, with a detection limit as low as 5,000 cells in a voxel of 250 × 250 × 250 µm in dimension in vivo. Conclusion: Multicolor SPCCT is an innovative translational imaging tool that allows monitoring and quantification of therapeutic cells and their encapsulating scaffold transplanted in the damaged rat brain.

show abstract

Section: Discussionmentioning

confidence: 99%

Multicolor spectral photon counting CT monitors and quantifies therapeutic cells and their encapsulating scaffold in a model of brain damage

Cuccione¹,

Chhour²,

Dumot³

et al. 2020

Nanotheranostics

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the present study, no significant difference of diagnostic performance was found between the 2 injection protocols, probably because of the low contrast enhancement of peritoneal lesions observed, and because the injection protocol did not influence the POI and the diagnostic quality www.nature.com/scientificreports/ score. Regarding gadolinium contrast agent, our study adds to growing data demonstrating that it is a good candidate for SPCCT imaging as it allows good separation from body tissue and iodine based on its K-edge 29,33,36,68 . Taking into account that the amount of IV gadolinium of the protocol B was higher than the recommended clinical doses in MRI and the knowledge of gadolinium tissue deposition in brain and bone 69 , protocol A with IV appears to be more suitable for clinical research.…”

Section: Discussionmentioning

confidence: 84%

Spectral photon-counting CT imaging of colorectal peritoneal metastases: initial experience in rats

Thivolet

Bonnot

Blanchet

et al. 2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

computed tomography imaging plays a major role in the preoperative assessment of tumor burden by providing an accurate mapping of the distribution of peritoneal metastases (PM). Spectral Photon Counting Computed Tomography (SPCCT) is an innovative imaging modality that could overcome the current limitations of conventional CT, offering not only better spatial resolution but also better contrast resolution by allowing the discrimination of multiple contrast agents. Based on this capability, we tested the feasibility of SPCCT in the detection of PM at different time of tumor growth in 16 rats inoculated with CC531 cells using dual-contrast injection protocols in two compartments (i.e. intravenous iodine and intraperitoneal gadolinium or the reverse protocol), compared to surgery. For all peritoneal regions and for both protocols, sensitivity was 69%, specificity was 100% and accuracy was 80%, and the correlation with surgical exploration was strong (p = 0.97; p = 0.0001). No significant difference was found in terms of diagnostic performance, quality of peritoneal opacification or diagnostic quality between the 2 injection protocols. We also showed poor vascularization of peritoneal metastases by measuring low concentrations of contrast agent in the largest lesions using SPCCT, which was confirmed by immunohistochemical analyses. In conclusion, SPCCT using dualcontrast agent injection protocols in 2 compartments is a promising imaging modality to assess the extent of PM in a rat model. Peritoneal metastases (PM) are part of the natural history of most abdominal and gynecological malignancies and have long been considered as a terminal disease. Over the past decades, the development of cytoreductive surgery with or without intraoperative hyperthermal intraperitoneal chemotherapy (HIPEC) has led to an improvement in survival of selected patients with resectable disease 1-4. For colorectal cancer, this strategy has significantly improved oncology outcomes 4,5. The completeness of the cytoreductive surgery is a crucial endpoint and is directly associated with the extent and distribution of PM in the peritoneal cavity 6,7. However, this aggressive treatment is associated with substantial morbidity (30-40%) and a mortality rate that is reported to range from 0-10%, resulting in a further drastic selection of patients in the pre-treatment work-up 8,9. In this context, preoperative evaluation of the peritoneal tumor burden, although extremely challenging, is essential for the selection of eligible patients for curative treatment 10,11. Computed tomography (CT) remains the reference imaging modality to assess the extent of PM. Although magnetic resonance imaging (MRI) and positron emission tomography-CT (PET-CT) have good diagnostic performance in some PM etiologies, these modalities are mainly used as a complement to CT evaluation 10,12-17. However, even though CT imaging offers high spatial resolution and fast acquisition time, its main drawback is its lack of contrast resolution, leading to a significant underestimation ...

show abstract

“…Dualor multicontrast imaging with other contrast agents, such as ytterbium, tantalum, tungsten, and gold with K-edges of 61.3, 67.4, 69.5, and 80.7 keV, respectively, have also been proposed, since their K-edges are also located within the clinical x-ray spectrum. [35][36][37][38] Their quantitative accuracy and dose efficiency remain to be investigated. Last but not the least, the three-material model in the phantom study used pure water as the background basis material, which is much simplified compared to that in realistic clinical tasks, where the background material is soft tissue or blood.…”

Section: Discussionmentioning

confidence: 99%

Quantitative accuracy and dose efficiency of dual‐contrast imaging using dual‐energy CT: a phantom study

et al. 2019

View full text Add to dashboard Cite

Purpose To evaluate the quantitative accuracy and dose efficiency of simultaneous imaging of two contrast agents using dual‐energy computed tomography (DECT), two imaging tasks each representing one potential clinical application were investigated in a phantom study: biphasic liver imaging with iodine and gadolinium, and small bowel imaging with iodine and bismuth. Methods To separate and quantify mixtures of two contrast agents using a single DECT scan, mixed iodine and gadolinium samples were prepared with the contrast enhancement values corresponding to the late arterial (iodine) and the portal‐venous (gadolinium) phase for biphasic liver imaging. Mixed iodine and bismuth samples were prepared mimicking the arterial (iodine) and the enteric (bismuth) enhancement for small bowel imaging. For comparison to the reference condition of performing two single‐energy CT (SECT) scans, contrast samples were prepared separately to mimic separate scans in the arterial/venous phase and arterial/enteric enhancement. Samples were placed in a 35 cm wide water tank and scanned using a third‐generation dual‐source DECT scanner with three tube potential pairs: 80/Sn150, 90/Sn150, and 100/Sn150 kV, all with default dose partitioning between two x‐ray beams to acquire DECT data. The same scanner operated in a single‐energy mode acquired SECT data (120 kV). Total radiation dose (CTDIvol) was matched for the single‐scan DECT and the two‐scan SECT protocols. The DECT protocol was followed by a generic image‐based three‐material decomposition method to determine the material‐specific images, based on which concentrations of each basis material were quantified and noise levels were measured. To compare with the SECT images directly acquired with the SECT protocol, the concentration values in each contrast‐specific image were converted to CT numbers at 120 kV (i.e., virtual SECT (vSECT) images). The noise level and noise power spectra differences between the SECT and vSECT images were compared to evaluate the dose efficiency of the single‐scan DECT protocol. The impact of dose partitioning in the DECT protocol on quantitative dual‐contrast imaging performance was also studied. Results For each imaging task, contrast materials were accurately quantified against the nominal concentrations using the DECT data with strong correlation (R2 ≥ 0.98 for both imaging tasks). Compared to the SECT protocol, the DECT protocol was not dose efficient. With the optimal x‐ray tube potential pair 80/Sn150 kV, the noise level in vSECT images increased by 401%/488% (arterial/portal‐venous) for the biphasic liver imaging task and by 10%/41% (arterial/enteric) for the small bowel imaging task compared to that in SECT images. The corresponding radiation dose increase is 2410%/3357% for the biphasic liver imaging task and 21%/99% for the small bowel imaging task, respectively, to achieve the same noise as that in SECT images. This could be improved by adjusting the dose partitioning in DECT. Conclusions DECT can be used to simultaneously separate and quantify ...

show abstract

Assessment of candidate elements for development of spectral photon-counting CT specific contrast agents

Cited by 74 publications

References 66 publications

Multicolor spectral photon counting CT monitors and quantifies therapeutic cells and their encapsulating scaffold in a model of brain damage

Multicolor spectral photon counting CT monitors and quantifies therapeutic cells and their encapsulating scaffold in a model of brain damage

Spectral photon-counting CT imaging of colorectal peritoneal metastases: initial experience in rats

Quantitative accuracy and dose efficiency of dual‐contrast imaging using dual‐energy CT: a phantom study

Contact Info

Product

Resources

About