Dr. Juan Carlos Ramirez-Giraldo Profile

Dr. Juan Carlos Ramirez-Giraldo

Director CT R&D Collaborations

SPIE Involvement:

Author

Publications (9)

Proceedings Article | 18 October 2022 Open Access

Co-clinical photon counting CT research for multi-contrast imaging

C. Badea, D. Clark, A. Alphin, J. C. Ramirez-Giraldo, P. Bhandari, Y. Mowery, K. Ghaghada

Proceedings Volume 12304, 123040G (2022) https://doi.org/10.1117/12.2646399

KEYWORDS: Gadolinium, Tantalum, Tumors, Calcium, Denoising, Computed tomography, X-ray computed tomography, Scanners, Condition numbers, Reconstruction algorithms

Read Abstract +

DOWNLOAD PAPER

Proceedings Article | 15 February 2021 Presentation + Paper

A novel approach to calculating dual energy in the angiography suite

Julie DiNitto, Juan Carlo Ramirez-Giraldo, Michael Froehler

Proceedings Volume 11595, 115950V (2021) https://doi.org/10.1117/12.2581747

KEYWORDS: Iodine, Dual energy imaging, Blood, Angiography, Tin, Manufacturing, Ischemic stroke, Computed tomography, Calibration, Blood pressure

Read Abstract +

Purpose: Medical management after endovascular treatment (EVT) for acute ischemic stroke involves blood pressure management and antithrombotic medications which are strongly influenced by hemorrhagic complications of the procedure. In this study our aim is to modify a commercially available c-arm angiographic system to assess feasibility of distinguishing between blood and iodinated contrast using dual-energy CT technology. Methods: An angiographic C-arm system was manipulated with the addition of a flat sheet of tin (Sn) filtration with corresponding calibration. Two flat-panel cone-beam CT (FP-CBCT) were acquired at 70 kV and 125Sn kV. A multienergy CT phantom with iodine inserts at various concentrations ranging from 0.2 to 15 mg/cc was used to characterize the behavior (i.e. dual-energy ratios DER) of the materials as a function of the kVp pair. DER values were needed to adjust an existing material decomposition software. The accuracy of iodine quantification was assessed with inserts including solid water, iodine, blood and mixed iodine and blood; all with concentrations ranges relevant for stroke imaging. Results: Imaging indicated the ability to differentiate between blood and iodine for the use with FP-CBCT. Pure blood and iodine inserts fell within the 95% confidence interval for precision of contrast concentration measured. For iodine inserts, the error from expected measurement was 7.5% or under for inserts with concentrations above 2 mg/cc. Inserts containing a combination of blood and iodine were consistently reading 1 mg/ml or less deviations relative to the value of the material specified by the manufacturer, which represented a 25-35% error difference from the expected value. Conclusion: These results establish the reproducibility of the phantom values for dual energy calculations and suggest that this technology may be clinically useful after EVT for stroke. Improvements in the accuracy of the iodine/blood combination under dual energy evaluation is needed for other applications outside of the use for differentiating between hemorrhage and contrast staining.

Proceedings Article | 15 February 2021 Poster + Presentation + Paper

Automated patient-specific and organ-based image quality metrics on dual-energy CT datasets for large scale studies

Wanyi Fu, Juan Carlos Ramirez-Giraldo, Daniele Marin, Taylor Brunton Smith, Thomas Sauer, Yuqin Ding, Ehsan Samei

Proceedings Volume 11595, 1159530 (2021) https://doi.org/10.1117/12.2582231

KEYWORDS: Image quality, Computed tomography, Image segmentation, 3D modeling, Liver, Stomach, Spleen, Kidney, Image quality standards, Dual energy imaging

Read Abstract +

Proceedings Article | 1 March 2019 Paper

A framework for realistic virtual clinical trials in photon counting computed tomography

Ehsan Abadi, Brian Harrawood, Jayasai Rajagopal, Shobhit Sharma, Anuj Kapadia, Martin Sedlmair, Juan Carlos Ramirez, Karl Stierstorfer, W. Paul Segars, Ehsan Samei

Proceedings Volume 10948, 109484F (2019) https://doi.org/10.1117/12.2512898

KEYWORDS: Monte Carlo methods, Photon counting, Computed tomography, Clinical trials, Scanners, Medicine, Computer simulations

Read Abstract +

SPIE Journal Paper | 17 January 2018

Quantification of uncertainty in the assessment of coronary plaque in CCTA through a dynamic cardiac phantom and 3D-printed plaque model

Taylor Richards, Gregory Sturgeon, Juan Carlos Ramirez-Giraldo, Geoffrey Rubin, Lynne Hurwitz Koweek, William Paul Segars, Ehsan Samei

JMI, Vol. 5, Issue 01, 013501, (January 2018) https://doi.org/10.1117/12.10.1117/1.JMI.5.1.013501

KEYWORDS: Heart, Beam propagation method, 3D modeling, Image segmentation, Motion models, Electrocardiography, Computed tomography, Image quality, Motion measurement, Reconstruction algorithms

Read Abstract +

Proceedings Article | 9 March 2017 Paper

Quantification of the uncertainty in coronary CTA plaque measurements using dynamic cardiac phantom and 3D-printed plaque models

Taylor Richards, Gregory Sturgeon, Juan Carlos Ramirez-Giraldo, Geoffrey Rubin, Paul Segars, Ehsan Samei

Proceedings Volume 10132, 101325E (2017) https://doi.org/10.1117/12.2255592

KEYWORDS: Accuracy assessment, Image quality, Reliability, 3D modeling, Motion models, Heart, Electrocardiography, Computed tomography, Image segmentation, Tissues, Iodine, Temporal resolution

Read Abstract +

Proceedings Article | 17 March 2015 Paper

A multireader diagnostic performance study of low-contrast detectability on a third-generation dual-source CT scanner: filtered back projection versus advanced modeled iterative reconstruction

Justin Solomon, Achille Mileto, Juan Carlos Ramirez-Giraldo, Ehsan Samei

Proceedings Volume 9416, 94160D (2015) https://doi.org/10.1117/12.2081647

KEYWORDS: Reconstruction algorithms, Visible radiation, Computed tomography, Diagnostics, Scanners, Signal detection, Optical filters, Performance modeling, Image quality, Medicine

Read Abstract +

Proceedings Article | 24 February 2012 Paper

Correlation between model observer and human observer performance in CT imaging when lesion location is uncertain

Shuai Leng, Lifeng Yu, Lingyun Chen, Juan C. Ramirez Giraldo, Cynthia McCollough

Proceedings Volume 8313, 83131M (2012) https://doi.org/10.1117/12.912126

KEYWORDS: Computed tomography, Performance modeling, Signal detection, Image quality, Data modeling, Diagnostics, Mathematical modeling, X-ray computed tomography, Abdomen, Scanners

Read Abstract +

Proceedings Article | 22 March 2010 Paper

Non-convex prior image constrained compressed sensing (NC-PICCS)

Juan Carlos Ramírez Giraldo, Joshua Trzasko, Shuai Leng, Cynthia McCollough, Armando Manduca

Proceedings Volume 7622, 76222C (2010) https://doi.org/10.1117/12.837239

KEYWORDS: Compressed sensing, Computed tomography, Image quality, Reconstruction algorithms, In vivo imaging, Data acquisition, Image restoration, Computer simulations, Signal attenuation, Signal to noise ratio

Read Abstract +

Showing 5 of 9 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years