Development of a separability index for task specific characterization of spectral computed tomography.

Autor: Rajagopal JR; Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, NC 27705, United States; Medical Physics Graduate Program, Duke University Medical Center, Durham, NC 27705, United States; Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892, United States. Electronic address: jayasai.rajagopal@duke.edu., Farhadi F; Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892, United States; Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, United States., Solomon J; Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, NC 27705, United States; Medical Physics Graduate Program, Duke University Medical Center, Durham, NC 27705, United States; Clinical Imaging Physics Group, Duke University Medical Center, Durham, NC 27705, United States., Saboury B; Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892, United States., Sahbaee P; Siemens Medical Solutions USA, Malvern, PA 19335, United States., Negussie AH; Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892, United States., Pritchard WF; Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892, United States., Jones EC; Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD 20892, United States., Samei E; Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, NC 27705, United States; Medical Physics Graduate Program, Duke University Medical Center, Durham, NC 27705, United States; Clinical Imaging Physics Group, Duke University Medical Center, Durham, NC 27705, United States. Electronic address: esi.samei@duke.edu.
Jazyk: angličtina
Zdroj: Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) [Phys Med] 2024 Jun; Vol. 122, pp. 103382. Date of Electronic Publication: 2024 May 30.
DOI: 10.1016/j.ejmp.2024.103382
Abstrakt: Purpose: In this work, we define a signal detection based metrology to characterize the separability of two different multi-dimensional signals in spectral CT acquisitions.
Method: Signal response was modelled as a random process with a deterministic signal and stochastic noise component. A linear Hotelling observer was used to estimate a scalar test statistic distribution that predicts the likelihood of an intensity value belonging to a signal. Two distributions were estimated for two materials of interest and used to derive two metrics separability: a separability index (s') and the area under the curve of the test statistic distributions. Experimental and simulated data of photon-counting CT scanners were used to evaluate each metric. Experimentally, vials of iodine and gadolinium (2, 4, 8 mg/mL) were scanned at multiple tube voltages, tube currents and energy thresholds. Additionally, a simulated dataset with low tube current (10-150 mAs) and material concentrations (0.25-4 mg/mL) was generated.
Results: Experimental data showed that conditions favorable for low noise and expression of k-edge signal produced the highest separability. Material concentration had the greatest impact on separability. The simulated data showed that under more difficult separation conditions, difference in material concentration still had the greatest impact on separability.
Conclusion: The results demonstrate the utility of a task specific metrology to measure the overlap in signal between different materials in spectral CT. Using experimental and simulated data, the separability index was shown to describe the relationship between image formation factors and the signal responses of material.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ehsan Samei reports financial support was provided by National Institutes of Health. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Associazione Italiana di Fisica Medica e Sanitaria. All rights reserved.)
Databáze: MEDLINE
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