Evaluation of extracranial occlusive disease by digital subtraction angiography

Turski, Patrick A.; Strother, Charles M.; Turnipseed, William D.; Sackett, Joseph F.; Crummy, Andrew B.; Lieberman, Robert P.; Stieghorst, Michael F.

doi:10.1016/0090-3019(81)90224-x

Cited by 11 publications

(4 citation statements)

References 3 publications

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“…6,7 Due to the pre-injection and post-injection images being acquired several seconds apart, motion artifacts may compromise DSA studies. 7,8 While some patient motion can be mitigated, involuntary motion, such as respiratory and cardiac motion in pulmonary and cardiac imaging, or swallowing in head and neck imaging, are unavoidable. 9 For this reason, DSA is not used to image the coronary arteries.…”

Section: Introductionmentioning

confidence: 99%

“…DSA subtracts images acquired before injection of an iodine contrast agent from those acquired after injection, enabling the removal of non‐iodinated structures from the resulting images 6,7 . Due to the pre‐injection and post‐injection images being acquired several seconds apart, motion artifacts may compromise DSA studies 7,8 . While some patient motion can be mitigated, involuntary motion, such as respiratory and cardiac motion in pulmonary and cardiac imaging, or swallowing in head and neck imaging, are unavoidable 9 .…”

Section: Introductionmentioning

confidence: 99%

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Theoretical comparison of energy‐resolved and digital‐subtraction angiography

2022

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Background X‐ray coronary angiography is a sub‐optimal vascular imaging technique because it cannot suppress un‐enhanced anatomy that may obscure the visualization of coronary artery disease. Purpose The purpose of this paper is to evaluate the theoretical image quality of energy‐resolved x‐ray angiography (ERA) implemented with spectroscopic x‐ray detectors (SXDs), which may overcome limitations of x‐ray coronary angiography. Methods We modeled the large‐area signal‐difference‐to‐noise (SDNR) of contrast‐enhanced vasculature in ERA images and compared with that of digital‐subtraction angiography (DSA), which served as a gold standard vascular imaging technique. To this end, we used calibrated numerical models of the response of cadmium telluride SXDs including the effects of charge sharing, electronic noise, and energy thresholding. Our models assumed zero scatter, no pulse pile up and small signals such that image contrast is approximately linear in the area density of contrast agents. For DSA, we similarly modeled x‐ray detection by cesium iodide energy‐integrating detectors using validated numerical models. For ERA, we investigated iodine and gadolinium (Gd) contrast agents, two‐material and three‐material decompositions, analog charge summing for charge sharing correction, and optimized image quality with respect to the tube voltage and energy thresholds assuming cadmium telluride SXDs with three energy bins. Results Our analysis reveals that a three‐material decomposition using iodine contrast agents will require x‐ray exposures that are approximately 400 times those of DSA to achieve the same SDNR as DSA in coronary applications, and is therefore not feasible in a clinical setting. However, three‐material decompositions with Gd contrast agents have the potential to provide SDNR that is ∼45% of that of DSA for matched patient air kerma. For two‐material decompositions that suppress soft‐tissue, ERA has the potential to produce images with SDNR that is 50%–75% of that of DSA for matched patient air kermas but lower levels of tube loading. Achieving these SDNR levels will require the use of analog charge summing for charge sharing correction, which increased SDNR by up to a factor of 1.7 depending on the contrast agent and whether or not a two‐material or three‐material decomposition was assumed. Conclusions We conclude that three‐material ERA implemented with Gd contrast agents and two‐material ERA implemented with either iodine or Gd contrast agents, should be investigated as alternatives to DSA in situations where motion artifacts preclude the use of DSA, such as in coronary imaging.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical comparison of energy‐resolved and digital‐subtraction angiography

2022

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“…The five generations of CARs have been used in T cell therapy since its creation in the late 1980s, each with successive improvements in the intracellular signaling domain responsible for T cell activation. In the first-generation CARs, the intracellular T cell domain consisted of the CD3ζ chain [24,25]. The second-and third-generation CARs introduced one or two costimulatory molecules, CD28 and 4-1BB, respectively, to improve the persistence and efficacy of the CAR T cells [26,27].…”

Section: Car T Cell Design: Five Generations and Countingmentioning

confidence: 99%

Advances in CAR T Cell Therapy for Non-Small Cell Lung Cancer

Ma,

Das,

Prendergast

et al. 2023

CIMB

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Since its first approval by the FDA in 2017, tremendous progress has been made in chimeric antigen receptor (CAR) T cell therapy, the adoptive transfer of engineered, CAR-expressing T lymphocyte. CAR T cells are all composed of three main elements: an extracellular antigen-binding domain, an intracellular signaling domain responsible for T cell activation, and a hinge that joins these two domains. Continuous improvement has been made in CARs, now in their fifth generation, particularly in the intracellular signaling domain responsible for T cell activation. CAR T cell therapy has revolutionized the treatment of hematologic malignancies. Nonetheless, the use of CAR T cell therapy for solid tumors has not attained comparable levels of success. Here we review the challenges in achieving effective CAR T cell therapy in solid tumors, and emerging CAR T cells that have shown great promise for non-small cell lung cancer (NSCLC). A growing number of clinical trials have been conducted to study the effect of CAR T cell therapy on NSCLC, targeting different types of surface antigens. They include epidermal growth factor receptor (EGFR), mesothelin (MSLN), prostate stem cell antigen (PSCA), and mucin 1 (MUC1). Potential new targets such as erythropoietin-producing hepatocellular carcinoma A2 (EphA2), tissue factor (TF), and protein tyrosine kinase 7 (PTK7) are currently under investigation in clinical trials. The challenges in developing CAR T for NSCLC therapy and other approaches for enhancing CAR T efficacy are discussed. Finally, we provide our perspective on imaging CAR T cell action by reviewing the two main radionuclide-based CAR T cell imaging techniques, the direct labeling of CAR T cells or indirect labeling via a reporter gene.

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“…3,4 DSA subtracts an image acquired before injection of an iodine contrast agent from an image acquired after injection.Subtraction of the two images suppresses non-iodinated structures, enhancing vascular visualization. 5,6 Due to the pre-injection and post-injection images being acquired several seconds apart, DSA is susceptible to motion artifacts 7,8 and is therefore not used to visualize coronary arteries.…”

Section: Introductionmentioning

confidence: 99%

Experimental optimization of single‐exposure dual‐energy angiography with photon‐counting x‐ray detectors

Aubert

Tanguay

2022

Medical Physics

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Background: Photon-counting x-ray detectors may enable single-exposure dual-energy (DE) x-ray angiography. Purpose: The purpose of this paper is to experimentally optimize the energy thresholds and tube voltage for single-exposure DE x-ray angiography. Methods: We optimized single-exposure DE x-ray angiography using the iodine signal-difference-to-noise ratio (SDNR) per root patient air kerma (𝜅) as a figure of merit. We measured the iodine SDNR by imaging an iodine stepwedge immersed in a water tank with a depth of 30 cm in the direction of x-ray propagation. The stepwedge was imaged using tube voltages ranging from 90 to 150 kV and a cadmium telluride (CdTe) x-ray detector with two energy bins and analog charge summing for charge sharing suppression. The energy threshold that separates the two energy bins was varied from approximately 35 keV to approximately 75% of the maximum energy of the x-ray beam. Curve fitting was used to determine the threshold that maximized SDNR∕ √ 𝜅. The effect of scatter was determined from measurements of the scatter-to-primary ratios (SPRs) of the low-energy and high-energy images and a semi-empirical model of the relationship between SDNR and SPR. Using the optimal parameters, we imaged a phantom with vessel-simulating structures and background clutter. Results:The optimal energy thresholds increased monotonically from ∼50 to ∼85 keV over the range of tube voltages considered. For tube voltages greater than 90 kV, the optimal energy thresholds consistently allocated approximately two thirds of all detected primary photons to the low energy bin; this ratio was preserved without scatter. Consistent with prior modeling studies, SDNR∕ √ 𝜅 increased monotonically with tube voltage from 90 to 150 kV; SDNR∕ √ 𝜅 at 150 kV was approximately 38% higher than that at 90 kV for an iodine area density of ∼50 mg/cm 2 . Scatter reduced SDNR by approximately 25% for SPRs of ∼1 and 0.4 in low-energy and high-energy images, respectively. Conclusions: Achieving optimal image quality in single-exposure DE angiography with photon-counting x-ray detectors will require high tube voltages (i.e., >130 kV) and, for thick patients, energy thresholds that allocate approximately two thirds of all primary photons to the low-energy image. Future work will compare the image quality of singe-exposure photon-counting and kV-switching approaches to DE x-ray angiography.

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Evaluation of extracranial occlusive disease by digital subtraction angiography

Cited by 11 publications

References 3 publications

Theoretical comparison of energy‐resolved and digital‐subtraction angiography

Theoretical comparison of energy‐resolved and digital‐subtraction angiography

Advances in CAR T Cell Therapy for Non-Small Cell Lung Cancer

Experimental optimization of single‐exposure dual‐energy angiography with photon‐counting x‐ray detectors

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