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Shao M, Byrd DW, Mitra J, Behnia F, Lee JH, Iravani A, Sadic M, Chen DL, Wollenweber SD, Abbey CK, Kinahan PE, Ahn S. A deep learning anthropomorphic model observer for a detection task in PET. Med Phys 2024. [PMID: 39008812 DOI: 10.1002/mp.17303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/15/2024] [Accepted: 06/24/2024] [Indexed: 07/17/2024] Open
Abstract
BACKGROUND Lesion detection is one of the most important clinical tasks in positron emission tomography (PET) for oncology. An anthropomorphic model observer (MO) designed to replicate human observers (HOs) in a detection task is an important tool for assessing task-based image quality. The channelized Hotelling observer (CHO) has been the most popular anthropomorphic MO. Recently, deep learning MOs (DLMOs), mostly based on convolutional neural networks (CNNs), have been investigated for various imaging modalities. However, there have been few studies on DLMOs for PET. PURPOSE The goal of the study is to investigate whether DLMOs can predict HOs better than conventional MOs such as CHO in a two-alternative forced-choice (2AFC) detection task using PET images with real anatomical variability. METHODS Two types of DLMOs were implemented: (1) CNN DLMO, and (2) CNN-SwinT DLMO that combines CNN and Swin Transformer (SwinT) encoders. Lesion-absent PET images were reconstructed from clinical data, and lesion-present images were reconstructed with adding simulated lesion sinogram data. Lesion-present and lesion-absent PET image pairs were labeled by eight HOs consisting of four radiologists and four image scientists in a 2AFC detection task. In total, 2268 pairs of lesion-present and lesion-absent images were used for training, 324 pairs for validation, and 324 pairs for test. CNN DLMO, CNN-SwinT DLMO, CHO with internal noise, and non-prewhitening matched filter (NPWMF) were compared in the same train-test paradigm. For comparison, six quantitative metrics including prediction accuracy, mean squared errors (MSEs) and correlation coefficients, which measure how well a MO predicts HOs, were calculated in a 9-fold cross-validation experiment. RESULTS In terms of the accuracy and MSE metrics, CNN DLMO and CNN-SwinT DLMO showed better performance than CHO and NPWMF, and CNN-SwinT DLMO showed the best performance among the MOs evaluated. CONCLUSIONS DLMO can predict HOs more accurately than conventional MOs such as CHO in PET lesion detection. Combining SwinT and CNN encoders can improve the DLMO prediction performance compared to using CNN only.
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Affiliation(s)
- Muhan Shao
- GE HealthCare Technology and Innovation Center, Niskayuna, New York, USA
| | - Darrin W Byrd
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Jhimli Mitra
- GE HealthCare Technology and Innovation Center, Niskayuna, New York, USA
| | - Fatemeh Behnia
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Jean H Lee
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Amir Iravani
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Murat Sadic
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Delphine L Chen
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | | | - Craig K Abbey
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, California, USA
| | - Paul E Kinahan
- Department of Radiology, University of Washington, Seattle, Washington, USA
| | - Sangtae Ahn
- GE HealthCare Technology and Innovation Center, Niskayuna, New York, USA
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Cece E, Meyrat P, Torino E, Verdier O, Colarieti-Tosti M. Spatio-Temporal Positron Emission Tomography Reconstruction with Attenuation and Motion Correction. J Imaging 2023; 9:231. [PMID: 37888338 PMCID: PMC10607376 DOI: 10.3390/jimaging9100231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/02/2023] [Accepted: 10/11/2023] [Indexed: 10/28/2023] Open
Abstract
The detection of cancer lesions of a comparable size to that of the typical system resolution of modern scanners is a long-standing problem in Positron Emission Tomography. In this paper, the effect of composing an image-registering convolutional neural network with the modeling of the static data acquisition (i.e., the forward model) is investigated. Two algorithms for Positron Emission Tomography reconstruction with motion and attenuation correction are proposed and their performance is evaluated in the detectability of small pulmonary lesions. The evaluation is performed on synthetic data with respect to chosen figures of merit, visual inspection, and an ideal observer. The commonly used figures of merit-Peak Signal-to-Noise Ratio, Recovery Coefficient, and Signal Difference-to-Noise Ration-give inconclusive responses, whereas visual inspection and the Channelised Hotelling Observer suggest that the proposed algorithms outperform current clinical practice.
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Affiliation(s)
- Enza Cece
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 10044 Stockholm, Sweden; (E.C.); (P.M.)
- Deptartment of Chemical Engineering, Materials and Production, University of Naples Federico II, 80131 Naples, Italy;
| | - Pierre Meyrat
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 10044 Stockholm, Sweden; (E.C.); (P.M.)
| | - Enza Torino
- Deptartment of Chemical Engineering, Materials and Production, University of Naples Federico II, 80131 Naples, Italy;
| | - Olivier Verdier
- Department of Computing, Mathematics, and Physics, HVL Western Norway University of Applied Sciences, 5063 Bergen, Norway;
| | - Massimiliano Colarieti-Tosti
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 10044 Stockholm, Sweden; (E.C.); (P.M.)
- Department of Clinical Science, Intervention & Technology, Karolinska Institutet, 171 77 Stockholm, Sweden
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Jang H, Baek J. Convolutional neural network-based model observer for signal known statistically task in breast tomosynthesis images. Med Phys 2023; 50:6390-6408. [PMID: 36971505 DOI: 10.1002/mp.16395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/20/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND Since human observer studies are resource-intensive, mathematical model observers are frequently used to assess task-based image quality. The most common implementation of these model observers assume that the signal information is exactly known. However, these tasks cannot thoroughly represent situations where the signal information is not exactly known in terms of size and shape. PURPOSE Considering the limitations of the tasks for which signal information is exactly known, we proposed a convolutional neural network (CNN)-based model observer for signal known statistically (SKS) and background known statistically (BKS) detection tasks in breast tomosynthesis images. METHODS A wide parameter search was conducted from six different acquisition angles (i.e., 10°, 20°, 30°, 40°, 50°, and 60°) within the same dose level (i.e., 2.3 mGy) under two separate acquisition schemes: (1) constant total number of projections, and (2) constant angular separation between projections. Two different types of signals: spherical (i.e., SKE tasks) and spiculated (i.e., SKS tasks) were used. The detection performance of the CNN-based model observer was compared with that of the Hotelling observer (HO) instead of the IO. Pixel-wise gradient-weighted class activation mapping (pGrad-CAM) map was extracted from each reconstructed tomosynthesis image to provide an intuitive understanding of the trained CNN-based model observer. RESULTS The CNN-based model observer achieved a higher detection performance compared to that of the HO for all tasks. Moreover, the improvement in its detection performance was greater for SKS tasks compared to that for SKE tasks. These results demonstrated that the addition of nonlinearity improved the detection performance owing to the variation of the background and signal. Interestingly, the pGrad-CAM results effectively localized the class-specific discriminative region, further supporting the quantitative evaluation results of the CNN-based model observer. In addition, we verified that the CNN-based model observer required fewer images to achieve the detection performance of the HO. CONCLUSIONS In this work, we proposed a CNN-based model observer for SKS and BKS detection tasks in breast tomosynthesis images. Throughout the study, we demonstrated that the detection performance of the proposed CNN-based model observer was superior to that of the HO.
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Affiliation(s)
- Hanjoo Jang
- School of Integrated Technology Yonsei University, Seoul, South Korea
| | - Jongduk Baek
- Department of Artificial Intelligence, College of Computing, Yonsei University, Seoul, South Korea
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Sá Dos Reis C, Caso M, Dolenc L, Howick K, Lemmen R, Meira A, Shatku F, Aymon E, Ghotra SS. Optimisation of exposure parameters using a phantom for thoracic spine radiographs in antero-posterior and lateral views. Radiography (Lond) 2023; 29:870-877. [PMID: 37419047 DOI: 10.1016/j.radi.2023.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023]
Abstract
INTRODUCTION To investigate the exposure parameters for thoracic spine/(TS) radiography that allows the image acquisition at the lowest dose possible, while maintaining an adequate image quality/(IQ) to identify all relevant anatomical criteria. METHODS An experimental phantom study was conducted, and 48 different radiographs of TS (24 AP/24 lateral) were acquired. The Automatic Exposure Control/(AEC) with the central sensor was used to select the beam intensity, while Source-to-Detector-Distance/(SDD) (AP:115/125 cm; Lateral:115/150 cm), tube potential (AP:70/81/90 kVp; Lateral: 81/90/102 kVp), use of grid/no grid and focal spot (fine/broad) were manipulated. IQ was assessed by observers with ViewDEX. Effective Dose (ED) was estimated using PCXMC2.0 software. Descriptive statistics paired with intraclass correlation coefficient (ICC) were applied to analyse data. RESULTS The ED increased with a greater SDD for lateral-view, presenting a significant difference (p = 0.038), however IQ was not affected. For both AP and lateral, the use of grid had a significant effect on ED (p < 0.001). Despite the images acquired without grid had lower IQ scores, the observers considered the IQ adequate for clinical use. A 20% reduction in ED (0.042mSv-0.033 mSv) was observed when increasing the beam energy from 70 to 90 kVp for AP grid in. The observers ICC ranged from moderate to good (0.5-0.75) in lateral and good to excellent (0.75-0.9) for AP views. CONCLUSIONS The optimised parameters in this context were 115 cm SDD, 90 kVp with grid for the best IQ and lowest ED. Further studies in clinical setting are necessary to enlarge the context and cover different body habitus and equipment. IMPLICATIONS FOR PRACTICE The SDD impacts on dose for TS; Higher kVp and grid are necessary to better image quality.
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Affiliation(s)
- C Sá Dos Reis
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne, 1011, Switzerland.
| | - M Caso
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne, 1011, Switzerland.
| | - L Dolenc
- Medical Imaging and Radiotherapy Department, Faculty of Health Sciences, University of Ljubljana, Slovenia.
| | - K Howick
- Radiography and Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, Ireland.
| | - R Lemmen
- Department of Medical Imaging and Radiation Therapy, Hanze University of Applied Sciences, Groningen, the Netherlands.
| | - A Meira
- Medical Imaging and Radiation Therapy, Lisbon School of Health Technology (ESTeSL)/IPL, Lisbon, Portugal.
| | - F Shatku
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne, 1011, Switzerland.
| | - E Aymon
- Department of Radiology, Hospital of Sion, Avenue Du Grand-Champsec 80, 1950, Sion, Switzerland.
| | - S S Ghotra
- School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne, 1011, Switzerland; Department of Radiology, Hospital of Yverdon-les-Bains (eHnv), 1400 Yverdon-les-Bains, Switzerland.
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Spatio-temporal generalized Model Observers methods for Low Contrast Detectability assessment in digital angiography: Application to moving targets. Phys Med 2023; 108:102556. [PMID: 36898289 DOI: 10.1016/j.ejmp.2023.102556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 02/15/2023] [Accepted: 02/18/2023] [Indexed: 03/11/2023] Open
Abstract
The purpose of this work is to investigate the feasibility of spatio-temporal generalized Model Observer methods for protocol optimization programs in the field of interventional radiography. Two Model Observers were taken under examination: a Channelized Hotelling Observer with 24 spatio-temporal Gabor channels and a Non Pre-Whitening Model Observer with two different implementations of the spatio-temporal contrast sensitivity function. The images of targets, both stationary and in motion, were acquired in fluoroscopic mode using a CDRAD phantom for signal-present images and an homogenous slab of PMMA for signal-absent ones. After the processing, these images were used to build three series of two alternative forced choice experiments, designed to simulate tasks of clinical interest, and submitted to three human observers in order to set a goal on detectability. A first set of images was used for model tuning and subsequently the verified models were validated throughout a second set of images. Results from the validation phase, for both models, show good agreement with the human observer performances (Root Mean Square Error RMSE ≤ 12%). The tuning phase emerges as a crucial step in building models for angiographic dynamic images; the final agreement underlines the good capability of these spatio-temporal models in simulating human performances, allowing to consider them as a useful and worthwhile tool in protocol optimization when dynamic images are involved.
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Li K, Zhou W, Li H, Anastasio MA. A Hybrid Approach for Approximating the Ideal Observer for Joint Signal Detection and Estimation Tasks by Use of Supervised Learning and Markov-Chain Monte Carlo Methods. IEEE TRANSACTIONS ON MEDICAL IMAGING 2022; 41:1114-1124. [PMID: 34898433 PMCID: PMC9128572 DOI: 10.1109/tmi.2021.3135147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The ideal observer (IO) sets an upper performance limit among all observers and has been advocated for assessing and optimizing imaging systems. For general joint detection and estimation (detection-estimation) tasks, estimation ROC (EROC) analysis has been established for evaluating the performance of observers. However, in general, it is difficult to accurately approximate the IO that maximizes the area under the EROC curve. In this study, a hybrid method that employs machine learning is proposed to accomplish this. Specifically, a hybrid approach is developed that combines a multi-task convolutional neural network and a Markov-Chain Monte Carlo (MCMC) method in order to approximate the IO for detection-estimation tasks. Unlike traditional MCMC methods, the hybrid method is not limited to use of specific utility functions. In addition, a purely supervised learning-based sub-ideal observer is proposed. Computer-simulation studies are conducted to validate the proposed method, which include signal-known-statistically/background-known-exactly and signal-known-statistically/background-known-statistically tasks. The EROC curves produced by the proposed method are compared to those produced by the MCMC approach or analytical computation when feasible. The proposed method provides a new approach for approximating the IO and may advance the application of EROC analysis for optimizing imaging systems.
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Guo X, Zhang L, Xing Y. Analytical covariance estimation for iterative CT reconstruction methods. Biomed Phys Eng Express 2022; 8. [PMID: 35213850 DOI: 10.1088/2057-1976/ac58bf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/25/2022] [Indexed: 11/11/2022]
Abstract
Covariance of reconstruction images are useful to analyze the magnitude and correlation of noise in the evaluation of systems and reconstruction algorithms. The covariance estimation requires a big number of image samples that are hard to acquire in reality. A covariance propagation method from projection by a few noisy realizations is studied in this work. Based on the property of convergent points of cost funtions, the proposed method is composed of three steps, (1) construct a relationship between the covariance of projection and corresponding reconstruction from cost functions at its convergent point, (2) simplify the covariance relationship constructed in (1) by introducing an approximate gradient of penalties, and (3) obtain an analytical covariance estimation according to the simplified relationship in (2). Three approximation methods for step (2) are studied: the linear approximation of the gradient of penalties (LAM), the Taylor apprximation (TAM), and the mixture of LAM and TAM (MAM). TV and qGGMRF penalized weighted least square methods are experimented on. Results from statistical methods are used as reference. Under the condition of unstable 2nd derivative of penalties such as TV, the covariance image estimated by LAM accords to reference well but of smaller values, while the covarianc estimation by TAM is quite off. Under the conditon of relatively stable 2nd derivative of penalties such as qGGMRF, TAM performs well and LAM is again with a negative bias in magnitude. MAM gives a best performance under both conditions by combining LAM and TAM. Results also show that only one noise realization is enough to obtain reasonable covariance estimation analytically, which is important for practical usage. This work suggests the necessity and a new way to estimate the covariance for non-quadratically penalized reconstructions. Currently, the proposed method is computationally expensive for large size reconstructions.Computational efficiency is our future work to focus.
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Affiliation(s)
- Xiaoyue Guo
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Beijing, People's Republic of China
| | - Li Zhang
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Beijing, People's Republic of China
| | - Yuxiang Xing
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Beijing, People's Republic of China
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Sghaier M, Chouzenoux E, Pesquet JC, Muller S. A Novel Task-Based reconstruction approach for digital breast tomosynthesis. Med Image Anal 2021; 77:102341. [PMID: 34998110 DOI: 10.1016/j.media.2021.102341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 10/19/2022]
Abstract
The reconstruction of a volumetric image from Digital Breast Tomosynthesis (DBT) measurements is an ill-posed inverse problem, for which existing iterative regularized approaches can provide a good solution. However, the clinical task is somehow omitted in the derivation of those techniques, although it plays a primary role in the radiologist diagnosis. In this work, we address this issue by introducing a novel variational formulation for DBT reconstruction, tailored for a specific clinical task, namely the detection of microcalcifications. Our method aims at simultaneously enhancing the detectability performance and enabling a high-quality restoration of the background breast tissues. Our contribution is threefold. First, we introduce an original task-based reconstruction framework through the proposition of a detectability function inspired from mathematical model observers. Second, we propose a novel total-variation regularizer where the gradient field accounts for the different morphological contents of the imaged breast. Third, we integrate the two developed measures into a cost function, minimized thanks to a new form of the Majorize Minimize Memory Gradient (3MG) algorithm. We conduct a numerical comparison of the convergence speed of the proposed method with those of standard convex optimization algorithms. Experimental results show the interest of our DBT reconstruction approach, qualitatively and quantitatively.
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Affiliation(s)
- Maissa Sghaier
- University of Paris-Saclay, CentraleSupélec, CVN, Inria, 09 Rue Joliot Curie, Gif-sur-Yvette 91190, France; GE Healthcare, 283 Rue de la Minière, Buc 78530, France.
| | - Emilie Chouzenoux
- University of Paris-Saclay, CentraleSupélec, CVN, Inria, 09 Rue Joliot Curie, Gif-sur-Yvette 91190, France.
| | - Jean-Christophe Pesquet
- University of Paris-Saclay, CentraleSupélec, CVN, Inria, 09 Rue Joliot Curie, Gif-sur-Yvette 91190, France.
| | - Serge Muller
- GE Healthcare, 283 Rue de la Minière, Buc 78530, France.
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Zhang X, Kelkar VA, Granstedt J, Li H, Anastasio MA. Impact of deep learning-based image super-resolution on binary signal detection. J Med Imaging (Bellingham) 2021; 8:065501. [PMID: 34796251 PMCID: PMC8594450 DOI: 10.1117/1.jmi.8.6.065501] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/27/2021] [Indexed: 11/14/2022] Open
Abstract
Purpose: Deep learning-based image super-resolution (DL-SR) has shown great promise in medical imaging applications. To date, most of the proposed methods for DL-SR have only been assessed using traditional measures of image quality (IQ) that are commonly employed in the field of computer vision. However, the impact of these methods on objective measures of IQ that are relevant to medical imaging tasks remains largely unexplored. We investigate the impact of DL-SR methods on binary signal detection performance. Approach: Two popular DL-SR methods, the super-resolution convolutional neural network and the super-resolution generative adversarial network, were trained using simulated medical image data. Binary signal-known-exactly with background-known-statistically and signal-known-statistically with background-known-statistically detection tasks were formulated. Numerical observers (NOs), which included a neural network-approximated ideal observer and common linear NOs, were employed to assess the impact of DL-SR on task performance. The impact of the complexity of the DL-SR network architectures on task performance was quantified. In addition, the utility of DL-SR for improving the task performance of suboptimal observers was investigated. Results: Our numerical experiments confirmed that, as expected, DL-SR improved traditional measures of IQ. However, for many of the study designs considered, the DL-SR methods provided little or no improvement in task performance and even degraded it. It was observed that DL-SR improved the task performance of suboptimal observers under certain conditions. Conclusions: Our study highlights the urgent need for the objective assessment of DL-SR methods and suggests avenues for improving their efficacy in medical imaging applications.
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Affiliation(s)
- Xiaohui Zhang
- University of Illinois at Urbana–Champaign, Department of Bioengineering, Urbana, Illinois, United States
| | - Varun A. Kelkar
- University of Illinois at Urbana–Champaign, Department of Electrical and Computer Engineering, Urbana, Illinois, United States
| | - Jason Granstedt
- University of Illinois at Urbana–Champaign, Department of Computer Science, Urbana, Illinois, United States
| | - Hua Li
- University of Illinois at Urbana–Champaign, Department of Bioengineering, Urbana, Illinois, United States
- University of Illinois at Urbana–Champaign, Cancer Center at Illinois, Urbana, Illinois, United States
- Carle Foundation Hospital, Carle Cancer Center, Urbana, Illinois, United States
| | - Mark A. Anastasio
- University of Illinois at Urbana–Champaign, Department of Bioengineering, Urbana, Illinois, United States
- University of Illinois at Urbana–Champaign, Department of Electrical and Computer Engineering, Urbana, Illinois, United States
- University of Illinois at Urbana–Champaign, Department of Computer Science, Urbana, Illinois, United States
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Jha AK, Myers KJ, Obuchowski NA, Liu Z, Rahman MA, Saboury B, Rahmim A, Siegel BA. Objective Task-Based Evaluation of Artificial Intelligence-Based Medical Imaging Methods:: Framework, Strategies, and Role of the Physician. PET Clin 2021; 16:493-511. [PMID: 34537127 DOI: 10.1016/j.cpet.2021.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Artificial intelligence-based methods are showing promise in medical imaging applications. There is substantial interest in clinical translation of these methods, requiring that they be evaluated rigorously. We lay out a framework for objective task-based evaluation of artificial intelligence methods. We provide a list of available tools to conduct this evaluation. We outline the important role of physicians in conducting these evaluation studies. The examples in this article are proposed in the context of PET scans with a focus on evaluating neural network-based methods. However, the framework is also applicable to evaluate other medical imaging modalities and other types of artificial intelligence methods.
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Affiliation(s)
- Abhinav K Jha
- Department of Biomedical Engineering, Mallinckrodt Institute of Radioly, Alvin J. Siteman Cancer Center, Washington University in St. Louis, 510 S Kingshighway Boulevard, St Louis, MO 63110, USA.
| | - Kyle J Myers
- Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration (FDA), Silver Spring, MD, USA
| | | | - Ziping Liu
- Department of Biomedical Engineering, Washington University in St. Louis, 1 Brookings Drive, St Louis, MO 63130, USA
| | - Md Ashequr Rahman
- Department of Biomedical Engineering, Washington University in St. Louis, 1 Brookings Drive, St Louis, MO 63130, USA
| | - Babak Saboury
- Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Arman Rahmim
- Department of Radiology, Department of Physics, University of British Columbia, BC Cancer, BC Cancer Research Institute, 675 West 10th Avenue, Office 6-112, Vancouver, British Columbia V5Z 1L3, Canada
| | - Barry A Siegel
- Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Alvin J. Siteman Cancer Center, Washington University School of Medicine, 510 S Kingshighway Boulevard #956, St Louis, MO 63110, USA
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Li K, Zhou W, Li H, Anastasio MA. Assessing the Impact of Deep Neural Network-Based Image Denoising on Binary Signal Detection Tasks. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:2295-2305. [PMID: 33929958 PMCID: PMC8673589 DOI: 10.1109/tmi.2021.3076810] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A variety of deep neural network (DNN)-based image denoising methods have been proposed for use with medical images. Traditional measures of image quality (IQ) have been employed to optimize and evaluate these methods. However, the objective evaluation of IQ for the DNN-based denoising methods remains largely lacking. In this work, we evaluate the performance of DNN-based denoising methods by use of task-based IQ measures. Specifically, binary signal detection tasks under signal-known-exactly (SKE) with background-known-statistically (BKS) conditions are considered. The performance of the ideal observer (IO) and common linear numerical observers are quantified and detection efficiencies are computed to assess the impact of the denoising operation on task performance. The numerical results indicate that, in the cases considered, the application of a denoising network can result in a loss of task-relevant information in the image. The impact of the depth of the denoising networks on task performance is also assessed. The presented results highlight the need for the objective evaluation of IQ for DNN-based denoising technologies and may suggest future avenues for improving their effectiveness in medical imaging applications.
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Vegas-Sánchez-Ferrero G, Ramos-Llordén G, Estépar RSJ. Harmonization of in-plane resolution in CT using multiple reconstructions from single acquisitions. Med Phys 2021; 48:6941-6961. [PMID: 34432901 DOI: 10.1002/mp.15186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 07/19/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To providea methodology that removes the spatial variability of in-plane resolution using different CT reconstructions. The methodology does not require any training, sinogram, or specific reconstruction method. METHODS The methodology is formulated as a reconstruction problem. The desired sharp image is modeled as an unobservable variable to be estimated from an arbitrary number of observations with spatially variant resolution. The methodology comprises three steps: (1) density harmonization, which removes the density variability across reconstructions; (2) point spread function (PSF) estimation, which estimates a spatially variant PSF with arbitrary shape; (3) deconvolution, which is formulated as a regularized least squares problem. The assessment was performed with CT scans of phantoms acquired with three different Siemens scanners (Definition AS, Definition AS+, Drive). Four low-dose acquisitions reconstructed with backprojection and iterative methods were used for the resolution harmonization. A sharp, high-dose (HD) reconstruction was used as a validation reference. The different factors affecting the in-plane resolution (radial, angular, and longitudinal) were studied with regression analysis of the edge decay (between 10% and 90% of the edge spread function (ESF) amplitude). RESULTS Results showed that the in-plane resolution improves remarkably and the spatial variability is substantially reduced without compromising the noise characteristics. The modulated transfer function (MTF) also confirmed a pronounced increase in resolution. The resolution improvement was also tested by measuring the wall thickness of tubes simulating airways. In all scanners, the resolution harmonization obtained better performance than the HD, sharp reconstruction used as a reference (up to 50 percentage points). The methodology was also evaluated in clinical scans achieving a noise reduction and a clear improvement in thin-layered structures. The estimated ESF and MTF confirmed the resolution improvement. CONCLUSION We propose a versatile methodology to reduce the spatial variability of in-plane resolution in CT scans by leveraging different reconstructions available in clinical studies. The methodology does not require any sinogram, training, or specific reconstruction, and it is not limited to a fixed number of input images. Therefore, it can be easily adopted in multicenter studies and clinical practice. The results obtained with our resolution harmonization methodology evidence its suitability to reduce the spatially variant in-plane resolution in clinical CT scans without compromising the reconstruction's noise characteristics. We believe that the resolution increase achieved by our methodology may contribute in more accurate and reliable measurements of small structures such as vasculature, airways, and wall thickness.
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Affiliation(s)
- Gonzalo Vegas-Sánchez-Ferrero
- Applied ChestImaging Laboratory (ACIL), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Gabriel Ramos-Llordén
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Raúl San José Estépar
- Applied ChestImaging Laboratory (ACIL), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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13
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Lago MA, Abbey CK, Eckstein MP. Medical image quality metrics for foveated model observers. J Med Imaging (Bellingham) 2021; 8:041209. [PMID: 34423070 DOI: 10.1117/1.jmi.8.4.041209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/20/2021] [Indexed: 11/14/2022] Open
Abstract
Purpose: A recently proposed model observer mimics the foveated nature of the human visual system by processing the entire image with varying spatial detail, executing eye movements, and scrolling through slices. The model can predict how human search performance changes with signal type and modality (2D versus 3D), yet its implementation is computationally expensive and time-consuming. Here, we evaluate various image quality metrics using extensions of the classic index of detectability expression and assess foveated model observers for search tasks. Approach: We evaluated foveated extensions of a channelized Hotelling and nonprewhitening matched filter model with an eye filter. The proposed methods involve calculating a model index of detectability ( d ' ) for each retinal eccentricity and combining these with a weighting function into a single detectability metric. We assessed different versions of the weighting function that varied in the required measurements of the human observers' search (no measurements, eye movement patterns, size of the image, and median search times). Results: We show that the index of detectability across eccentricities weighted using the eye movement patterns of observers best predicted human performance in 2D versus 3D search performance for a small microcalcification-like signal and a larger mass-like. The metric with a weighting function based on median search times was the second best predicting human results. Conclusions: The findings provide a set of model observer tools to evaluate image quality in the early stages of imaging system evaluation or design without implementing the more computationally complex foveated search model.
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Affiliation(s)
- Miguel A Lago
- University of California at Santa Barbara, Department of Psychological and Brain Sciences, Santa Barbara, California, United States
| | - Craig K Abbey
- University of California at Santa Barbara, Department of Psychological and Brain Sciences, Santa Barbara, California, United States
| | - Miguel P Eckstein
- University of California at Santa Barbara, Department of Psychological and Brain Sciences, Santa Barbara, California, United States.,University of California at Santa Barbara, Department of Electrical and Computer Engineering, Santa Barbara, California, United States
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14
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Han M, Shim H, Baek J. Low-dose CT denoising via convolutional neural network with an observer loss function. Med Phys 2021; 48:5727-5742. [PMID: 34387360 DOI: 10.1002/mp.15161] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 07/09/2021] [Accepted: 08/08/2021] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Convolutional neural network (CNN)-based denoising is an effective method for reducing complex computed tomography (CT) noise. However, the image blur induced by denoising processes is a major concern. The main source of image blur is the pixel-level loss (e.g., mean squared error [MSE] and mean absolute error [MAE]) used to train a CNN denoiser. To reduce the image blur, feature-level loss is utilized to train a CNN denoiser. A CNN denoiser trained using visual geometry group (VGG) loss can preserve the small structures, edges, and texture of the image.However, VGG loss, derived from an ImageNet-pretrained image classifier, is not optimal for training a CNN denoiser for CT images. ImageNet contains natural RGB images, so the features extracted by the ImageNet-pretrained model cannot represent the characteristics of CT images that are highly correlated with diagnosis. Furthermore, a CNN denoiser trained with VGG loss causes bias in CT number. Therefore, we propose to use a binary classification network trained using CT images as a feature extractor and newly define the feature-level loss as observer loss. METHODS As obtaining labeled CT images for training classification network is difficult, we create labels by inserting simulated lesions. We conduct two separate classification tasks, signal-known-exactly (SKE) and signal-known-statistically (SKS), and define the corresponding feature-level losses as SKE loss and SKS loss, respectively. We use SKE loss and SKS loss to train CNN denoiser. RESULTS Compared to pixel-level losses, a CNN denoiser trained using observer loss (i.e., SKE loss and SKS loss) is effective in preserving structure, edge, and texture. Observer loss also resolves the bias in CT number, which is a problem of VGG loss. Comparing observer losses using SKE and SKS tasks, SKS yields images having a more similar noise structure to reference images. CONCLUSIONS Using observer loss for training CNN denoiser is effective to preserve structure, edge, and texture in denoised images and prevent the CT number bias. In particular, when using SKS loss, denoised images having a similar noise structure to reference images are generated.
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Affiliation(s)
- Minah Han
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
| | - Hyunjung Shim
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
| | - Jongduk Baek
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
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15
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Pouget E, Dedieu V. Impact of iterative reconstruction algorithms on the applicability of Fourier-based detectability index for x-ray CT imaging. Med Phys 2021; 48:4229-4241. [PMID: 34075595 DOI: 10.1002/mp.15015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 05/17/2021] [Accepted: 05/23/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The increasing application of iterative reconstruction algorithms in clinical computed tomography to improve image quality and reduce radiation dose, elicits strong interest, and needs model observers to optimize CT scanning protocols objectively and efficiently. The current paradigm for evaluating imaging system performance relies on Fourier methods, which presuppose a linear, wide-sense stationary system. Long-range correlations introduced by iterative reconstruction algorithms may narrow the applicability of Fourier techniques. Differences in the implementation of reconstruction algorithms between manufacturers add further complexity. The present work set out to quantify the errors entailed by the use of Fourier methods, which can lead to design decisions that do not correlate with detectability. METHODS To address this question, we evaluated the noise properties and the detectability index of the ideal linear observer using the spatial approach and the Fourier-based approach. For this purpose, a homogeneous phantom was imaged on two scanners: the Revolution CT (GE Healthcare) and the Somatom Definition AS+ (Siemens Healthcare) at different exposure levels. Images were reconstructed using different strength levels of IR algorithms available on the systems considered: Adaptative Statistical Iterative Reconstruction (ASIR-V) and Sinogram Affirmed Iterative Reconstruction (SAFIRE). RESULTS Our findings highlight that the spatial domain estimate of the detectability index is higher than the Fourier domain estimate. This trend is found to be dependent on the specific regularization used by IR algorithms as well as the signal to be detected. The eigenanalysis of the noise covariance matrix and of its circulant approximation yields explanation about the evoked trends. In particular, this analysis suggests that the predictive power of the Fourier-based ideal linear observer depends on the ability of each basis analyzed to be relevant to the signal to be detected. CONCLUSION The applicability of Fourier techniques is dependent on the specific regularization used by IR algorithms. These results argue for verifying the assumptions made when using Fourier methods since Fourier-task-based detectability index does not always correlate with signal detectability.
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Affiliation(s)
- Eléonore Pouget
- Department of Medical Physics, Jean Perrin Comprehensive Cancer Center, Clermont-Ferrand, F-63000, France.,Clermont-Ferrand University, UMR 1240 INSERM IMoST, Clermont-Ferrand, F-63000, France
| | - Véronique Dedieu
- Department of Medical Physics, Jean Perrin Comprehensive Cancer Center, Clermont-Ferrand, F-63000, France.,Clermont-Ferrand University, UMR 1240 INSERM IMoST, Clermont-Ferrand, F-63000, France
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16
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Gomez-Cardona D, Favazza CP, Leng S, Schueler BA, Fetterly KA. Task-specific efficient channel selection and bias management for Gabor function channelized Hotelling observer model for the assessment of x-ray angiography system performance. Med Phys 2021; 48:3638-3653. [PMID: 33656177 DOI: 10.1002/mp.14813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 12/23/2020] [Accepted: 02/18/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Channelized Hotelling observer (CHO) models have been implemented to assess imaging performance in x-ray angiography systems. While current methods are appropriate for assessing unprocessed images of moving test objects upon uniform-exposure backgrounds, they are inadequate for assessing conditions which more appropriately mimic clinical imaging conditions including the combination of moving test objects, complex anthropomorphic backgrounds, and image processing. In support of this broad goal, the purpose of this work was to develop theory and methods to automatically select a subset of task-specific efficient Gabor channels from a task-generic Gabor channel base set. Also, previously described theory and methods to manage detectability index (d') bias due to nonrandom temporal variations in image electronic noise will be revisited herein. METHODS Starting with a base set of 96 Gabor channels, backward elimination of channels was used to automatically identify an "efficient" channel subset which reduced the number of channels retained in the subset while maintaining the magnitude of the d' estimate. The concept of a pixelwise Hotelling observer (PHO) model was introduced and similarly implemented to assess the performance of the efficient-channel CHO model. Bias in d' estimates arising from temporally variable nonstationary noise was modeled as a bivariate probability density function for normal distributions, where one variable corresponds to the signal from the test object and the other variable corresponds to the signal from temporally variable nonstationary noise. Theory and methods were tested on uniform-exposure unprocessed angiography images with detector target dose (DTD) of 6, 18, and 120 nGy containing static disk-shaped test objects with diameter in the range of 0.5 to 4 mm. RESULTS Considering all DTD levels and test object sizes, the proposed method reduced the number of Gabor channels in the final subset by 63-82% compared to the original 96 Gabor channel base set, while maintaining a mean relative performance ( ( d CHO ' / d PHO ' ) × 100 % ) of 95% ± 4% with respect to the reference PHO model. Experimental results demonstrated that the bivariate approach to account for bias due to temporally variable nonstationary noise resulted in improved correlation between the CHO and PHO models as compared to a previously proposed univariate approach. CONCLUSIONS Computationally efficient backward elimination can be used to select an efficient subset of Gabor channels from an initial channel base set without substantially compromising the magnitude of the d' estimate. Bias due to temporally variable nonstationary noise can be modeled through a bivariate approach leading to an improved unbiased estimate of d'.
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Affiliation(s)
- Daniel Gomez-Cardona
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.,Department of Imaging, Gundersen Health System, 1900 South Ave, La Crosse, WI, 54601, USA
| | - Christopher P Favazza
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Shuai Leng
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Beth A Schueler
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Kenneth A Fetterly
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.,Department of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
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17
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Othman N, Simon AC, Montagu T, Berteloot L, Grévent D, Habib Geryes B, Benkreira M, Bigand E, Capdeville S, Desrousseaux J, Farman B, Garnier E, Gempp S, Nigoul JM, Nomikossoff N, Vincent M. Toward a comparison and an optimization of CT protocols using new metrics of dose and image quality part I: prediction of human observers using a model observer for detection and discrimination tasks in low-dose CT images in various scanning conditions. Phys Med Biol 2021; 66. [PMID: 33887706 DOI: 10.1088/1361-6560/abfad8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 04/22/2021] [Indexed: 11/11/2022]
Abstract
In the context of reducing the patient dose coming from CT scanner examinations without penalizing the diagnosis, the assessment of both patient dose and image quality (IQ) with relevant metrics is crucial. The present study represents the first stage in a larger work, aiming to compare and optimize CT protocols using dose and IQ new metrics. We proposed here to evaluate the capacity of the Non-PreWhitening matched filter with an eye (NPWE) model observer to be a robust and accurate estimation of IQ. We focused our work on two types of clinical tasks: a low contrast detection task and a discrimination task. We designed a torso-shaped phantom, including Plastic Water®slabs with cylindrical inserts of different diameters, sections and compositions. We led a human observer study with 13 human observers on images acquired in multiple irradiation and reconstruction scanning conditions (voltage, pitch, slice thickness, noise level of the reconstruction algorithm, energy level in dual-energy mode and dose), to evaluate the behavior of the model observer compared to the human responses faced to changing conditions. The model observer presented the same trends as the human observers with generally better results. We rescaled the NPWE model on the human responses by scanning conditions (kVp, pitch, slice thickness) to obtain the best agreement between both observer types, estimated using the Bland-Altman method. The impact of some scanning parameters was estimated using the correct answer rate given by the rescaled NPWE model, for both tasks and each insert size. In particular, the comparison between the dual-energy mode at 74 keV and the single-energy mode at 120 kVp showed that, if the 120 kVp voltage provided better results for the smallest insert at the lower doses for both tasks, their responses were equivalent in many cases.
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Affiliation(s)
- Nadia Othman
- Université Paris-Saclay, CEA, List, F-91120 Palaiseau, France
| | | | - Thierry Montagu
- Université Paris-Saclay, CEA, List, F-91120 Palaiseau, France
| | - Laureline Berteloot
- Necker-Enfants Malades University Hospital, Paediatric Radiology Department, Paris, France
| | - David Grévent
- Necker-Enfants Malades University Hospital, Paediatric Radiology Department, Paris, France
| | - Bouchra Habib Geryes
- Necker-Enfants Malades University Hospital, Paediatric Radiology Department, Paris, France
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18
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Protocol Optimization Considerations for Implementing Deep Learning CT Reconstruction. AJR Am J Roentgenol 2021; 216:1668-1677. [PMID: 33852337 DOI: 10.2214/ajr.20.23397] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE. Previous advances over filtered back projection (FBP) have incorporated model-based iterative reconstruction. The purpose of this study was to characterize the latest advance in image reconstruction, that is, deep learning. The focus was on applying characterization results of a deep learning approach to decisions about clinical CT protocols. MATERIALS AND METHODS. A proprietary deep learning image reconstruction (DLIR) method was characterized against an existing advanced adaptive statistical iterative reconstruction method (ASIR-V) and FBP from the same vendor. The metrics used were contrast-to-noise ratio, spatial resolution as a function of contrast level, noise texture (i.e., noise power spectra [NPS]), noise scaling as a function of slice thickness, and CT number consistency. The American College of Radiology accreditation phantom and a uniform water phantom were used at a range of doses and slice thicknesses for both axial and helical acquisition modes. RESULTS. ASIR-V and DLIR were associated with improved contrast-to-noise ratio over FBP for all doses and slice thicknesses. No dose or contrast dependencies of spatial resolution were observed for ASIR-V or DLIR. NPS results showed DLIR maintained an FBP-like noise texture whereas ASIR-V shifted the NPS to lower frequencies. Noise changed with dose and slice thickness in the same manner for ASIR-V and FBP. DLIR slice thickness noise scaling differed from FBP, exhibiting less noise penalty with decreasing slice thickness. No clinically significant changes were observed in CT numbers for any measurement condition. CONCLUSION. In a phantom model, DLIR does not suffer from the concerns over reduction in spatial resolution and introduction of poor noise texture associated with previous methods.
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19
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Lago MA, Abbey CK, Eckstein MP. Foveated Model Observers for Visual Search in 3D Medical Images. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:1021-1031. [PMID: 33315556 PMCID: PMC7994931 DOI: 10.1109/tmi.2020.3044530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Model observers have a long history of success in predicting human observer performance in clinically-relevant detection tasks. New 3D image modalities provide more signal information but vastly increase the search space to be scrutinized. Here, we compared standard linear model observers (ideal observers, non-pre-whitening matched filter with eye filter, and various versions of Channelized Hotelling models) to human performance searching in 3D 1/f2.8 filtered noise images and assessed its relationship to the more traditional location known exactly detection tasks and 2D search. We investigated two different signal types that vary in their detectability away from the point of fixation (visual periphery). We show that the influence of 3D search on human performance interacts with the signal's detectability in the visual periphery. Detection performance for signals difficult to detect in the visual periphery deteriorates greatly in 3D search but not in 3D location known exactly and 2D search. Standard model observers do not predict the interaction between 3D search and signal type. A proposed extension of the Channelized Hotelling model (foveated search model) that processes the image with reduced spatial detail away from the point of fixation, explores the image through eye movements, and scrolls across slices can successfully predict the interaction observed in humans and also the types of errors in 3D search. Together, the findings highlight the need for foveated model observers for image quality evaluation with 3D search.
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20
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Li Y, Chen J, Brown JL, Treves ST, Cao X, Fahey FH, Sgouros G, Bolch WE, Frey EC. DeepAMO: a multi-slice, multi-view anthropomorphic model observer for visual detection tasks performed on volume images. J Med Imaging (Bellingham) 2021; 8:041204. [PMID: 33521164 DOI: 10.1117/1.jmi.8.4.041204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/31/2020] [Indexed: 11/14/2022] Open
Abstract
Purpose: We propose a deep learning-based anthropomorphic model observer (DeepAMO) for image quality evaluation of multi-orientation, multi-slice image sets with respect to a clinically realistic 3D defect detection task. Approach: The DeepAMO is developed based on a hypothetical model of the decision process of a human reader performing a detection task using a 3D volume. The DeepAMO is comprised of three sequential stages: defect segmentation, defect confirmation (DC), and rating value inference. The input to the DeepAMO is a composite image, typical of that used to view 3D volumes in clinical practice. The output is a rating value designed to reproduce a human observer's defect detection performance. In stages 2 and 3, we propose: (1) a projection-based DC block that confirms defect presence in two 2D orthogonal orientations and (2) a calibration method that "learns" the mapping from the features of stage 2 to the distribution of observer ratings from the human observer rating data (thus modeling inter- or intraobserver variability) using a mixture density network. We implemented and evaluated the DeepAMO in the context of Tc 99 m -DMSA SPECT imaging. A human observer study was conducted, with two medical imaging physics graduate students serving as observers. A 5 × 2 -fold cross-validation experiment was conducted to test the statistical equivalence in defect detection performance between the DeepAMO and the human observer. We also compared the performance of the DeepAMO to an unoptimized implementation of a scanning linear discriminant observer (SLDO). Results: The results show that the DeepAMO's and human observer's performances on unseen images were statistically equivalent with a margin of difference ( Δ AUC ) of 0.0426 at p < 0.05 , using 288 training images. A limited implementation of an SLDO had a substantially higher AUC (0.99) compared to the DeepAMO and human observer. Conclusion: The results show that the DeepAMO has the potential to reproduce the absolute performance, and not just the relative ranking of human observers on a clinically realistic defect detection task, and that building conceptual components of the human reading process into deep learning-based models can allow training of these models in settings where limited training images are available.
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Affiliation(s)
- Ye Li
- Johns Hopkins University, Whiting School of Engineering, Department of Electrical and Computer Engineering, Baltimore, Maryland, United States.,Johns Hopkins University, School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, United States
| | - Junyu Chen
- Johns Hopkins University, Whiting School of Engineering, Department of Electrical and Computer Engineering, Baltimore, Maryland, United States.,Johns Hopkins University, School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, United States
| | - Justin L Brown
- University of Florida, J. Crayton Pruitt Family Department of Biomedical Engineering, Gainesville, Florida, United States
| | - S Ted Treves
- Brigham and Women's Hospital, Department of Radiology, Boston, Massachusetts, United States.,Harvard Medical School, Department of Radiology, Boston, Massachusetts, United States
| | - Xinhua Cao
- Harvard Medical School, Department of Radiology, Boston, Massachusetts, United States.,Boston Children's Hospital, Department of Radiology, Boston, Massachusetts, United States
| | - Frederic H Fahey
- Harvard Medical School, Department of Radiology, Boston, Massachusetts, United States.,Boston Children's Hospital, Department of Radiology, Boston, Massachusetts, United States
| | - George Sgouros
- Johns Hopkins University, School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, United States
| | - Wesley E Bolch
- University of Florida, J. Crayton Pruitt Family Department of Biomedical Engineering, Gainesville, Florida, United States
| | - Eric C Frey
- Johns Hopkins University, Whiting School of Engineering, Department of Electrical and Computer Engineering, Baltimore, Maryland, United States.,Johns Hopkins University, School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, United States
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21
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Abadi E, Segars WP, Tsui BMW, Kinahan PE, Bottenus N, Frangi AF, Maidment A, Lo J, Samei E. Virtual clinical trials in medical imaging: a review. J Med Imaging (Bellingham) 2020; 7:042805. [PMID: 32313817 PMCID: PMC7148435 DOI: 10.1117/1.jmi.7.4.042805] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/23/2020] [Indexed: 12/13/2022] Open
Abstract
The accelerating complexity and variety of medical imaging devices and methods have outpaced the ability to evaluate and optimize their design and clinical use. This is a significant and increasing challenge for both scientific investigations and clinical applications. Evaluations would ideally be done using clinical imaging trials. These experiments, however, are often not practical due to ethical limitations, expense, time requirements, or lack of ground truth. Virtual clinical trials (VCTs) (also known as in silico imaging trials or virtual imaging trials) offer an alternative means to efficiently evaluate medical imaging technologies virtually. They do so by simulating the patients, imaging systems, and interpreters. The field of VCTs has been constantly advanced over the past decades in multiple areas. We summarize the major developments and current status of the field of VCTs in medical imaging. We review the core components of a VCT: computational phantoms, simulators of different imaging modalities, and interpretation models. We also highlight some of the applications of VCTs across various imaging modalities.
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Affiliation(s)
- Ehsan Abadi
- Duke University, Department of Radiology, Durham, North Carolina, United States
| | - William P. Segars
- Duke University, Department of Radiology, Durham, North Carolina, United States
| | - Benjamin M. W. Tsui
- Johns Hopkins University, Department of Radiology, Baltimore, Maryland, United States
| | - Paul E. Kinahan
- University of Washington, Department of Radiology, Seattle, Washington, United States
| | - Nick Bottenus
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
- University of Colorado Boulder, Department of Mechanical Engineering, Boulder, Colorado, United States
| | - Alejandro F. Frangi
- University of Leeds, School of Computing, Leeds, United Kingdom
- University of Leeds, School of Medicine, Leeds, United Kingdom
| | - Andrew Maidment
- University of Pennsylvania, Department of Radiology, Philadelphia, Pennsylvania, United States
| | - Joseph Lo
- Duke University, Department of Radiology, Durham, North Carolina, United States
| | - Ehsan Samei
- Duke University, Department of Radiology, Durham, North Carolina, United States
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22
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Anton M, Veldkamp WJH, Hernandez-Giron I, Elster C. RDI[Formula: see text]a regression detectability index for quality assurance in: x-ray imaging. Phys Med Biol 2020; 65:085017. [PMID: 32109907 DOI: 10.1088/1361-6560/ab7b2e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Novel iterative image reconstruction methods can help reduce the required radiation dose in x-ray diagnostics such as computed tomography (CT), while maintaining sufficient image quality. Since some of the established image quality measures are not appropriate for reliably judging the quality of images derived by iterative methods, alternative approaches such as task-specific quality assessment would be highly desirable for acceptance or constancy testing. Task-based image quality methods are also closer to tasks performed by the radiologists, such as lesion detection. However, this approach is usually hampered by a huge workload, since hundreds of images are usually required for its application. It is demonstrated that the proposed approach works reliably on the basis of significantly fewer images, and that it correlates well with results obtained from human observers.
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Affiliation(s)
- M Anton
- Physikalisch-Technische Bundesanstalt Braunschweig and Berlin, Berlin, Germany
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23
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Mason A, Rioux J, Clarke SE, Costa A, Schmidt M, Keough V, Huynh T, Beyea S. Comparison of Objective Image Quality Metrics to Expert Radiologists' Scoring of Diagnostic Quality of MR Images. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:1064-1072. [PMID: 31535985 DOI: 10.1109/tmi.2019.2930338] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Image quality metrics (IQMs) such as root mean square error (RMSE) and structural similarity index (SSIM) are commonly used in the evaluation and optimization of accelerated magnetic resonance imaging (MRI) acquisition and reconstruction strategies. However, it is unknown how well these indices relate to a radiologist's perception of diagnostic image quality. In this study, we compare the image quality scores of five radiologists with the RMSE, SSIM, and other potentially useful IQMs: peak signal to noise ratio (PSNR) multi-scale SSIM (MSSSIM), information-weighted SSIM (IWSSIM), gradient magnitude similarity deviation (GMSD), feature similarity index (FSIM), high dynamic range visible difference predictor (HDRVDP), noise quality metric (NQM), and visual information fidelity (VIF). The comparison uses a database of MR images of the brain and abdomen that have been retrospectively degraded by noise, blurring, undersampling, motion, and wavelet compression for a total of 414 degraded images. A total of 1017 subjective scores were assigned by five radiologists. IQM performance was measured via the Spearman rank order correlation coefficient (SROCC) and statistically significant differences in the residuals of the IQM scores and radiologists' scores were tested. When considering SROCC calculated from combining scores from all radiologists across all image types, RMSE and SSIM had lower SROCC than six of the other IQMs included in the study (VIF, FSIM, NQM, GMSD, IWSSIM, and HDRVDP). In no case did SSIM have a higher SROCC or significantly smaller residuals than RMSE. These results should be considered when choosing an IQM in future imaging studies.
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Lee C, Han M, Baek J. Human observer performance on in-plane digital breast tomosynthesis images: Effects of reconstruction filters and data acquisition angles on signal detection. PLoS One 2020; 15:e0229915. [PMID: 32163472 PMCID: PMC7067468 DOI: 10.1371/journal.pone.0229915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 02/17/2020] [Indexed: 11/29/2022] Open
Abstract
For digital breast tomosynthesis (DBT) systems, we investigate the effects of the reconstruction filters for different data acquisition angles on signal detection. We simulated a breast phantom with a 30% volume glandular fraction (VGF) of breast anatomy using the power law spectrum and modeled the breast mass as a spherical object with a 1 mm diameter. Projection data were acquired using two different data acquisition angles and numbers of projection view pairs, and in-plane breast images were reconstructed using the Feldkamp-Davis-Kress (FDK) algorithm with three different reconstruction filter schemes. To measure the ability to detect a signal, we conducted the human observer study with a binary detection task and compared the signal detectability of human to that of channelized Hotelling observer (CHO) with Laguerre-Gauss (LG) channels and dense difference-of-Gaussian (D-DOG) channels. We also measured the contrast-to-noise ratio (CNR), signal power spectrum (SPS), and β values of the anatomical noise power spectrum (NPS) to show the association between human observer performance and these traditional metrics. Our results show that using a slice thickness (ST) filter degraded the signal detection performance of human observers at the same data acquisition angle. This could be predicted by D-DOG CHO with internal noise, but the correlation between the traditional metrics and signal detectability was not observed in this work.
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Affiliation(s)
- Changwoo Lee
- Center for Medical Convergence Metrology, Korea Research Institute of Standards and Science (KRISS), Daejeon, South Korea
| | - Minah Han
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
| | - Jongduk Baek
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
- * E-mail:
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25
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Kim G, Han M, Shim H, Baek J. A convolutional neural network‐based model observer for breast CT images. Med Phys 2020; 47:1619-1632. [DOI: 10.1002/mp.14072] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 01/02/2020] [Accepted: 01/22/2020] [Indexed: 01/21/2023] Open
Affiliation(s)
- Gihun Kim
- School of Integrated Technology and Yonsei Institute of Convergence Technology Yonsei University 162‐1Incheon South Korea
| | - Minah Han
- School of Integrated Technology and Yonsei Institute of Convergence Technology Yonsei University 162‐1Incheon South Korea
| | - Hyunjung Shim
- School of Integrated Technology and Yonsei Institute of Convergence Technology Yonsei University 162‐1Incheon South Korea
| | - Jongduk Baek
- School of Integrated Technology and Yonsei Institute of Convergence Technology Yonsei University 162‐1Incheon South Korea
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26
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Tao A, Fetterly K. Integration of high velocity test object motion into a channelized Hotelling observer for the assessment of x-ray angiography systems. ACTA ACUST UNITED AC 2019; 64:185011. [DOI: 10.1088/1361-6560/ab39c4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Villa R, Paruccini N, Baglivi A, Signoriello M, Montezuma Velasquez RA, Morzenti S, De Ponti E, Crespi A. Model observers for Low Contrast Detectability evaluation in dynamic angiography: A feasible approach. Phys Med 2019; 64:89-97. [DOI: 10.1016/j.ejmp.2019.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 05/29/2019] [Accepted: 06/29/2019] [Indexed: 10/26/2022] Open
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Gupta P, Sinno Z, Glover JL, Paulter NG, Bovik AC. Predicting Detection Performance on Security X-Ray Images as a Function of Image Quality. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2019; 28:3328-3342. [PMID: 30714919 PMCID: PMC7433314 DOI: 10.1109/tip.2019.2896488] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Developing methods to predict how image quality affects the task performance is a topic of great interest in many applications. While such studies have been performed in the medical imaging community, little work has been reported in the security X-ray imaging literature. In this paper, we develop models that predict the effect of image quality on the detection of the improvised explosive device components by bomb technicians in images taken using portable X-ray systems. Using a newly developed NIST-LIVE X-Ray Task Performance Database, we created a set of objective algorithms that predict bomb technician detection performance based on the measures of image quality. Our basic measures are traditional image quality indicators (IQIs) and perceptually relevant natural scene statistics (NSS)-based measures that have been extensively used in visible light image quality prediction algorithms. We show that these measures are able to quantify the perceptual severity of degradations and can predict the performance of expert bomb technicians in identifying threats. Combining NSS- and IQI-based measures yields even better task performance prediction than either of these methods independently. We also developed a new suite of statistical task prediction models that we refer to as quality inspectors of X-ray images (QUIX); we believe this is the first NSS-based model for security X-ray images. We also show that QUIX can be used to reliably predict conventional IQI metric values on the distorted X-ray images.
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Han M, Baek J. A performance comparison of anthropomorphic model observers for breast cone beam CT images: A single‐slice and multislice study. Med Phys 2019; 46:3431-3441. [DOI: 10.1002/mp.13598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/22/2019] [Accepted: 05/13/2019] [Indexed: 12/28/2022] Open
Affiliation(s)
- Minah Han
- School of Integrated Technology and Yonsei Institute of Convergence Technology Yonsei University 162‐1Incheon South Korea
| | - Jongduk Baek
- School of Integrated Technology and Yonsei Institute of Convergence Technology Yonsei University 162‐1Incheon South Korea
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Channelized Hotelling observer correlation with human observers for low-contrast detection in liver CT images. J Med Imaging (Bellingham) 2019; 6:025501. [DOI: 10.1117/1.jmi.6.2.025501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 04/15/2019] [Indexed: 11/14/2022] Open
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Chen Y, Lou Y, Wang K, Kupinski MA, Anastasio MA. Reconstruction-Aware Imaging System Ranking by Use of a Sparsity-Driven Numerical Observer Enabled by Variational Bayesian Inference. IEEE TRANSACTIONS ON MEDICAL IMAGING 2019; 38:1251-1262. [PMID: 30475713 PMCID: PMC6559219 DOI: 10.1109/tmi.2018.2880870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
It is widely accepted that optimization of imaging system performance should be guided by task-based measures of image quality. It has been advocated that imaging hardware or data-acquisition designs should be optimized by use of an ideal observer that exploits full statistical knowledge of the measurement noise and class of objects to be imaged, without consideration of the reconstruction method. In practice, accurate and tractable models of the complete object statistics are often difficult to determine. Moreover, in imaging systems that employ compressive sensing concepts, imaging hardware and sparse image reconstruction are innately coupled technologies. In this paper, a sparsity-driven observer (SDO) that can be employed to optimize hardware by use of a stochastic object model describing object sparsity is described and investigated. The SDO and sparse reconstruction method can, therefore, be "matched" in the sense that they both utilize the same statistical information regarding the class of objects to be imaged. To efficiently compute the SDO test statistic, computational tools developed recently for variational Bayesian inference with sparse linear models are adopted. The use of the SDO to rank data-acquisition designs in a stylized example as motivated by magnetic resonance imaging is demonstrated. This paper reveals that the SDO can produce rankings that are consistent with visual assessments of the reconstructed images but different from those produced by use of the traditionally employed Hotelling observer.
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Bertolini M, Trojani V, Nitrosi A, Iori M, Sassatelli R, Ortenzia O, Ghetti C. Characterization of GE discovery IGS 740 angiography system by means of channelized Hotelling observer (CHO). ACTA ACUST UNITED AC 2019; 64:095002. [DOI: 10.1088/1361-6560/ab144c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hinton B, Ma L, Mahmoudzadeh AP, Malkov S, Fan B, Greenwood H, Joe B, Lee V, Strand F, Kerlikowske K, Shepherd J. Derived mammographic masking measures based on simulated lesions predict the risk of interval cancer after controlling for known risk factors: a case-case analysis. Med Phys 2019; 46:1309-1316. [PMID: 30697755 DOI: 10.1002/mp.13410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/13/2019] [Accepted: 01/17/2019] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Women with radiographically dense or texturally complex breasts are at increased risk for interval cancer, defined as cancers diagnosed after a normal screening examination. The purpose of this study was to create masking measures and apply them to identify interval risk in a population of women who experienced either screen-detected or interval cancers after controlling for breast density. METHODS We examined full-field digital screening mammograms acquired from 2006 to 2015. Examinations associated with 182 interval cancers were matched to 173 screen-detected cancers on age, race, exam date and time since last imaging examination. Local Image Quality Factor (IQF) values were calculated and used to create IQF maps that represented mammographic masking. We used various statistics to define global masking measures of these maps. Association of these masking measures with interval cancer vs screen-detected cancer was estimated using conditional logistic regression in a univariate and adjusted model for Breast Imaging-Reporting and Data System (BI-RADS) density. Receiver operator curves were calculated in each case to compare specificity vs sensitivity, and area under those curves were generated. Proportion of screen-detected cancer was estimated for stratifications of IQF features. RESULTS Several masking features showed significant association with interval compared to screen-detected cancers after adjusting for BI-RADS density (up to P = 2.52E-6), and the 10th percentile of the IQF value (P = 1.72E-3) showed the strongest improvement in the area under the receiver operator curve, increasing from 0.65 using only BI-RADS density to 0.69. The highest masking group had a 32% proportion of screen-detected cancers while the low masking group had a 69% proportion. CONCLUSIONS We conclude that computer vision methods using model observers may improve quantifying the probability of breast cancer detection beyond using breast density alone.
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Affiliation(s)
- Benjamin Hinton
- Department of Bioengineering, UC-San Francisco & UC-Berkeley Joint Program, San Francisco, CA, 94143, USA.,Department of Radiology and Biomedical Imaging, UC-San Francisco, San Francisco, CA, 94143, USA
| | - Lin Ma
- Kaiser Permanente Division of Research, Oakland, CA, 94612, USA
| | - Amir Pasha Mahmoudzadeh
- Department of Radiology and Biomedical Imaging, UC-San Francisco, San Francisco, CA, 94143, USA
| | | | - Bo Fan
- Department of Bioengineering, UC-San Francisco & UC-Berkeley Joint Program, San Francisco, CA, 94143, USA
| | - Heather Greenwood
- Department of Radiology and Biomedical Imaging, UC-San Francisco, San Francisco, CA, 94143, USA
| | - Bonnie Joe
- Department of Radiology and Biomedical Imaging, UC-San Francisco, San Francisco, CA, 94143, USA
| | - Vivian Lee
- Research Advocate, UCSF Breast Science Advocacy Core, San Francisco, CA, 94143, USA
| | - Fredrik Strand
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Solna, Sweden.,Department of Thoracic Radiology, Karolinska University Hospital, Solna, Sweden
| | - Karla Kerlikowske
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, 94143, USA
| | - John Shepherd
- University of Hawaii Cancer Center, Honolulu, HI, 96813, USA
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Khanin A, Anton M, Reginatto M, Elster C. Assessment of CT Image Quality Using a Bayesian Framework. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:2687-2694. [PMID: 29994114 DOI: 10.1109/tmi.2018.2848104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In computed tomography, there is a tradeoff between the quality of the reconstructed image and the radiation dose received by the patient. In order to find an appropriate compromise between the image quality of the reconstructed images and the radiation dose, it is important to have reliable methods for evaluating the quality of the reconstructed images. A successful family of methods for the assessment of image quality is task-based image quality assessment, which often involves the use of model observers, and which assesses the quality of the image reconstruction by deriving a figure of merit. Here, we present a Bayesian framework that can be used in task-based image quality assessment. Our framework is applicable to binary classification problems with normally distributed observations, and we make the additional assumption that the covariance matrix is the same in both image classes. We choose a particular non-informative prior for the parameters of our model, which allows us to derive an expression for the Bayes factor for the binary classification problem which to the best of our knowledge is novel. We introduce a novel model observer based on this Bayes factor. Further, we have developed a methodology for estimating the posterior distribution of the figure of merit for this type of classification problem. Compared with classical statistical approaches, our Bayesian approach has the advantage that it provides a full characterization of the uncertainty of the figure of merit. Our choice of prior allows us to design a simple Monte Carlo algorithm to efficiently sample the posterior of the figure of merit of the ideal observer, in contrast to common Bayesian procedures which rely on computationally expensive Markov chain Monte Carlo sampling. We have shown that for training samples of sufficient size, our estimated credible intervals for the figure of merit have coverage probabilities close to their credibility, so that our approach can reasonably be used within a classical statistical framework as well.
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Osadebey M, Pedersen M, Arnold D, Wendel-Mitoraj K. Image Quality Evaluation in Clinical Research: A Case Study on Brain and Cardiac MRI Images in Multi-Center Clinical Trials. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE-JTEHM 2018; 6:1800915. [PMID: 30197842 PMCID: PMC6126794 DOI: 10.1109/jtehm.2018.2855213] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 05/25/2018] [Accepted: 07/05/2018] [Indexed: 12/27/2022]
Abstract
Magnetic resonance imaging (MRI) system images are important components in the development of drugs because it can reveal the underlying pathology in diseases. Unfortunately, the processes of image acquisition, storage, transmission, processing, and analysis can influence image quality with the risk of compromising the reliability of MRI-based data. Therefore, it is necessary to monitor image quality throughout the different stages of the imaging workflow. This report describes a new approach to evaluate the quality of an MRI slice in multi-center clinical trials. The design philosophy assumes that an MRI slice, such as all natural images, possess statistical properties that can describe different levels of contrast degradation. A unique set of pixel configuration is assigned to each possible level of contrast-distorted MRI slice. Invocation of the central limit theorem results in two separate Gaussian distributions. The central limit theorem says that the mean and standard deviation of pixel configuration assigned to each possible level of contrast degradation will follow a normal distribution. The mean of each normal distribution corresponds to the mean and standard deviation of the underlying ideal image. Quality prediction processes for a test image can be summarized into four steps. The first step extracts local contrast feature image from the test image. The second step computes the mean and standard deviation of the feature image. The third step separately standardizes each normal distribution using the mean and standard deviation computed from the feature image. This gives two separate z-scores. The fourth step predicts the lightness contrast quality score and the texture contrast quality score from cumulative distribution function of the appropriate normal distribution. The proposed method was evaluated objectively on brain and cardiac MRI volume data using four different types and levels of degradation. The four types of degradation are Rician noise, circular blur, motion blur, and intensity nonuniformity also known as bias fields. Objective evaluation was validated using a proposed variation of difference of mean opinion scores. Results from performance evaluation show that the proposed method will be suitable to monitor and standardize image quality throughout the different stages of imaging workflow in large clinical trials. MATLAB implementation of the proposed objective quality evaluation method can be downloaded from (https://github.com/ezimic/Image-Quality-Evaluation).
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Affiliation(s)
| | - Marius Pedersen
- Department of Computer ScienceNorwegian University of Science and TechnologyN-2815GjovikNorway
| | - Douglas Arnold
- Montreal Neurological Institute, McGill UniversityMontrealQCH3A 2BCanada
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36
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Ba A, Abbey CK, Baek J, Han M, Bouwman RW, Balta C, Brankov J, Massanes F, Gifford HC, Hernandez-Giron I, Veldkamp WJH, Petrov D, Marshall N, Samuelson FW, Zeng R, Solomon JB, Samei E, Timberg P, Förnvik H, Reiser I, Yu L, Gong H, Bochud FO. Inter-laboratory comparison of channelized hotelling observer computation. Med Phys 2018; 45:3019-3030. [PMID: 29704868 DOI: 10.1002/mp.12940] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/11/2018] [Accepted: 04/15/2018] [Indexed: 01/14/2023] Open
Abstract
PURPOSE The task-based assessment of image quality using model observers is increasingly used for the assessment of different imaging modalities. However, the performance computation of model observers needs standardization as well as a well-established trust in its implementation methodology and uncertainty estimation. The purpose of this work was to determine the degree of equivalence of the channelized Hotelling observer performance and uncertainty estimation using an intercomparison exercise. MATERIALS AND METHODS Image samples to estimate model observer performance for detection tasks were generated from two-dimensional CT image slices of a uniform water phantom. A common set of images was sent to participating laboratories to perform and document the following tasks: (a) estimate the detectability index of a well-defined CHO and its uncertainty in three conditions involving different sized targets all at the same dose, and (b) apply this CHO to an image set where ground truth was unknown to participants (lower image dose). In addition, and on an optional basis, we asked the participating laboratories to (c) estimate the performance of real human observers from a psychophysical experiment of their choice. Each of the 13 participating laboratories was confidentially assigned a participant number and image sets could be downloaded through a secure server. Results were distributed with each participant recognizable by its number and then each laboratory was able to modify their results with justification as model observer calculation are not yet a routine and potentially error prone. RESULTS Detectability index increased with signal size for all participants and was very consistent for 6 mm sized target while showing higher variability for 8 and 10 mm sized target. There was one order of magnitude between the lowest and the largest uncertainty estimation. CONCLUSIONS This intercomparison helped define the state of the art of model observer performance computation and with thirteen participants, reflects openness and trust within the medical imaging community. The performance of a CHO with explicitly defined channels and a relatively large number of test images was consistently estimated by all participants. In contrast, the paper demonstrates that there is no agreement on estimating the variance of detectability in the training and testing setting.
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Affiliation(s)
- Alexandre Ba
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
| | - Craig K Abbey
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Jongduk Baek
- School of Integrated Technology, Yonsei University, 406-840, Incheon, Korea
| | - Minah Han
- School of Integrated Technology, Yonsei University, 406-840, Incheon, Korea
| | - Ramona W Bouwman
- Dutch Expert Centre for Screening, Radboud University Nijmegen Medical Centre (LRCB), P.O. Box 6873, 6503 GJ, Nijmegen, The Netherlands
| | - Christiana Balta
- Dutch Expert Centre for Screening, Radboud University Nijmegen Medical Centre (LRCB), P.O. Box 6873, 6503 GJ, Nijmegen, The Netherlands
| | - Jovan Brankov
- Department of Electrical and Computer Engineering, Illinois Institute of Technology, 3301 South Dearborn Street, Chicago, IL, 60616, USA
| | - Francesc Massanes
- Department of Electrical and Computer Engineering, Illinois Institute of Technology, 3301 South Dearborn Street, Chicago, IL, 60616, USA
| | - Howard C Gifford
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Irene Hernandez-Giron
- Radiology Department, Leiden University Medical Center (LUMC), Albinusdreef 2, 2333ZA, Leiden, The Netherlands
| | - Wouter J H Veldkamp
- Radiology Department, Leiden University Medical Center (LUMC), Albinusdreef 2, 2333ZA, Leiden, The Netherlands
| | - Dimitar Petrov
- Department of Medical Physics and Quality Assessment, KU Leuven, Leuven, Belgium
| | - Nicholas Marshall
- Department of Medical Physics and Quality Assessment, KU Leuven, Leuven, Belgium.,Department of Radiology, UZ Leuven, Leuven, Belgium
| | - Frank W Samuelson
- Division of Imaging, Diagnostics and Software Reliability, US Food and Drug Administration, 10903 New Hampshire Ave Building 62, Room 3102, Silver Spring, MD, 20903-1058, USA
| | - Rongping Zeng
- Division of Imaging, Diagnostics and Software Reliability, US Food and Drug Administration, 10903 New Hampshire Ave Building 62, Room 3102, Silver Spring, MD, 20903-1058, USA
| | - Justin B Solomon
- Carl E. Ravin Advanced Imaging Laboratories, Departments of Radiology, Electrical and Computer Engineering, Biomedical Engineering, and Physics, Clinical Imaging Physics Group, Medical Physics Graduate Program, Duke University, Durham, NC, 27705, USA
| | - Ehsan Samei
- Carl E. Ravin Advanced Imaging Laboratories, Departments of Radiology, Electrical and Computer Engineering, Biomedical Engineering, and Physics, Clinical Imaging Physics Group, Medical Physics Graduate Program, Duke University, Durham, NC, 27705, USA
| | - Pontus Timberg
- Department of Medical Radiation Physics, Translational Medicine Malmö, Lund University, Malmö, Sweden
| | - Hannie Förnvik
- Department of Medical Radiation Physics, Translational Medicine Malmö, Lund University, Malmö, Sweden
| | - Ingrid Reiser
- Department of Radiology, University of Chicago, 5841 S Maryland Ave, MC 2026, Chicago, IL, 60637, USA
| | - Lifeng Yu
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Hao Gong
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - François O Bochud
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland
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Han M, Kim B, Baek J. Human and model observer performance for lesion detection in breast cone beam CT images with the FDK reconstruction. PLoS One 2018; 13:e0194408. [PMID: 29543868 PMCID: PMC5854363 DOI: 10.1371/journal.pone.0194408] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 02/19/2018] [Indexed: 12/12/2022] Open
Abstract
We investigate the detectability of breast cone beam computed tomography images using human and model observers and the variations of exponent, β, of the inverse power-law spectrum for various reconstruction filters and interpolation methods in the Feldkamp-Davis-Kress (FDK) reconstruction. Using computer simulation, a breast volume with a 50% volume glandular fraction and a 2mm diameter lesion are generated and projection data are acquired. In the FDK reconstruction, projection data are apodized using one of three reconstruction filters; Hanning, Shepp-Logan, or Ram-Lak, and back-projection is performed with and without Fourier interpolation. We conduct signal-known-exactly and background-known-statistically detection tasks. Detectability is evaluated by human observers and their performance is compared with anthropomorphic model observers (a non-prewhitening observer with eye filter (NPWE) and a channelized Hotelling observer with either Gabor channels or dense difference-of-Gaussian channels). Our results show that the NPWE observer with a peak frequency of 7cyc/degree attains the best correlation with human observers for the various reconstruction filters and interpolation methods. We also discover that breast images with smaller β do not yield higher detectability in the presence of quantum noise.
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Affiliation(s)
- Minah Han
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
| | - Byeongjoon Kim
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
| | - Jongduk Baek
- School of Integrated Technology and Yonsei Institute of Convergence Technology, Yonsei University, Incheon, South Korea
- * E-mail:
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Wen G, Markey MK, Haygood TM, Park S. Model observer for assessing digital breast tomosynthesis for multi-lesion detection in the presence of anatomical noise. ACTA ACUST UNITED AC 2018; 63:045017. [DOI: 10.1088/1361-6560/aaab3a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wen G, Chang HC, Reinhold J, Lo JY, Markey MK. Virtual assessment of stereoscopic viewing of digital breast tomosynthesis projection images. J Med Imaging (Bellingham) 2018; 5:015501. [PMID: 29376103 DOI: 10.1117/1.jmi.5.1.015501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/12/2017] [Indexed: 11/14/2022] Open
Abstract
Digital breast tomosynthesis (DBT) acquires a series of projection images from different angles as an x-ray source rotates around the breast. Such imaging geometry lends DBT naturally to stereoscopic viewing as two projection images with a reasonable separation angle can easily form a stereo pair. This simulation study assessed the efficacy of stereo viewing of DBT projection images. Three-dimensional computational breast phantoms with realistically shaped synthetic lesions were scanned by three simulated DBT systems. The projection images were combined into a sequence of stereo pairs and presented to a stereomatching-based model observer for deciding lesion presence. Signal-to-noise ratio was estimated, and the detection performance with stack viewing of reconstructed slices was the benchmark. We have shown that: (1) stereo viewing of projection images may underperform stack viewing of reconstructed slices for current DBT geometries; (2) DBT geometries may impact the efficacy of the two viewing modes differently: narrow-arc and wide-arc geometries may be better for stereo viewing and stack viewing, respectively; (3) the efficacy of stereo viewing may be more robust than stack viewing to reductions in dose. While in principle stereo viewing is potentially effective for visualizing DBT data, effective stereo viewing may require specifically optimized DBT image acquisition.
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Affiliation(s)
- Gezheng Wen
- University of Texas at Austin, Electrical and Computer Engineering, Austin, Texas, United States
| | - Ho-Chang Chang
- University of Texas at Austin, Electrical and Computer Engineering, Austin, Texas, United States
| | - Jacob Reinhold
- University of Texas at Austin, Applied Research Laboratories, Austin, Texas, United States
| | - Joseph Y Lo
- Duke University School of Medicine, Diagnostic Radiology, Durham, North Carolina, United States
| | - Mia K Markey
- University of Texas at Austin, Biomedical Engineering, Austin, Texas, United States.,University of Texas MD Anderson Cancer Center, Imaging Physics, Houston, Texas, United States
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40
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Smith TB, Solomon J, Samei E. Estimating detectability index in vivo: development and validation of an automated methodology. J Med Imaging (Bellingham) 2017; 5:031403. [PMID: 29250570 DOI: 10.1117/1.jmi.5.3.031403] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/14/2017] [Indexed: 12/13/2022] Open
Abstract
This study's purpose was to develop and validate a method to estimate patient-specific detectability indices directly from patients' CT images (i.e., in vivo). The method extracts noise power spectrum (NPS) and modulation transfer function (MTF) resolution properties from each patient's CT series based on previously validated techniques. These are combined with a reference task function (10-mm disk lesion with [Formula: see text] HU contrast) to estimate detectability indices for a nonprewhitening matched filter observer model. This method was applied to CT data from a previous study in which diagnostic performance of 16 readers was measured for the task of detecting subtle, hypoattenuating liver lesions ([Formula: see text]), using a two-alternative-forced-choice (2AFC) method, over six dose levels and two reconstruction algorithms. In vivo detectability indices were estimated and compared to the human readers' binary 2AFC outcomes using a generalized linear mixed-effects statistical model. The results of this modeling showed that the in vivo detectability indices were strongly related to 2AFC outcomes ([Formula: see text]). Linear comparison between human-detection accuracy and model-predicted detection accuracy (for like conditions) resulted in Pearson and Spearman correlation coefficients exceeding 0.84. These results suggest the potential utility of using in vivo estimates of a detectability index for an automated image quality tracking system that could be implemented clinically.
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Affiliation(s)
- Taylor Brunton Smith
- Duke University, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Durham, North Carolina, United States
| | - Justin Solomon
- Duke University, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Durham, North Carolina, United States
| | - Ehsan Samei
- Duke University, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States.,Duke University, Medical Physics Graduate Program, Durham, North Carolina, United States.,Duke University Medical Center, Durham, North Carolina, United States
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41
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Bellesi L, Wyttenbach R, Gaudino D, Colleoni P, Pupillo F, Carrara M, Braghetti A, Puligheddu C, Presilla S. A simple method for low-contrast detectability, image quality and dose optimisation with CT iterative reconstruction algorithms and model observers. Eur Radiol Exp 2017; 1:18. [PMID: 29708194 PMCID: PMC5909349 DOI: 10.1186/s41747-017-0023-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/21/2017] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The aim of this work was to evaluate detection of low-contrast objects and image quality in computed tomography (CT) phantom images acquired at different tube loadings (i.e. mAs) and reconstructed with different algorithms, in order to find appropriate settings to reduce the dose to the patient without any image detriment. METHODS Images of supraslice low-contrast objects of a CT phantom were acquired using different mAs values. Images were reconstructed using filtered back projection (FBP), hybrid and iterative model-based methods. Image quality parameters were evaluated in terms of modulation transfer function; noise, and uniformity using two software resources. For the definition of low-contrast detectability, studies based on both human (i.e. four-alternative forced-choice test) and model observers were performed across the various images. RESULTS Compared to FBP, image quality parameters were improved by using iterative reconstruction (IR) algorithms. In particular, IR model-based methods provided a 60% noise reduction and a 70% dose reduction, preserving image quality and low-contrast detectability for human radiological evaluation. According to the model observer, the diameters of the minimum detectable detail were around 2 mm (up to 100 mAs). Below 100 mAs, the model observer was unable to provide a result. CONCLUSION IR methods improve CT protocol quality, providing a potential dose reduction while maintaining a good image detectability. Model observer can in principle be useful to assist human performance in CT low-contrast detection tasks and in dose optimisation.
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Affiliation(s)
- Luca Bellesi
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Rolf Wyttenbach
- Department of Radiology, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, Switzerland
- University of Bern, Bern, Switzerland
| | - Diego Gaudino
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Paolo Colleoni
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Francesco Pupillo
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Mauro Carrara
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
| | - Antonio Braghetti
- Department of Radiology, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, Switzerland
| | - Carla Puligheddu
- Department of Radiology, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, Switzerland
| | - Stefano Presilla
- Medical Physics Unit, Ente Ospedaliero Cantonale, Ospedale San Giovanni, Bellinzona, 6500 Switzerland
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Ott JG, Ba A, Racine D, Viry A, Bochud FO, Verdun FR. Assessment of low contrast detection in CT using model observers: Developing a clinically-relevant tool for characterising adaptive statistical and model-based iterative reconstruction. Z Med Phys 2017; 27:86-97. [DOI: 10.1016/j.zemedi.2016.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/15/2016] [Accepted: 04/08/2016] [Indexed: 10/21/2022]
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Lee J, Nishikawa RM, Reiser I, Zuley ML, Boone JM. Lack of agreement between radiologists: implications for image-based model observers. J Med Imaging (Bellingham) 2017; 4:025502. [PMID: 28491908 DOI: 10.1117/1.jmi.4.2.025502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 04/17/2017] [Indexed: 11/14/2022] Open
Abstract
We tested the agreement of radiologists' rankings of different reconstructions of breast computed tomography images based on their diagnostic (classification) performance and on their subjective image quality assessments. We used 102 pathology proven cases (62 malignant, 40 benign), and an iterative image reconstruction (IIR) algorithm to obtain 24 reconstructions per case with different image appearances. Using image feature analysis, we selected 3 IIRs and 1 clinical reconstruction and 50 lesions. The reconstructions produced a range of image quality from smooth/low-noise to sharp/high-noise, which had a range in classifier performance corresponding to AUCs of 0.62 to 0.96. Six experienced Mammography Quality Standards Act (MQSA) radiologists rated the likelihood of malignancy for each lesion. We conducted an additional reader study with the same radiologists and a subset of 30 lesions. Radiologists ranked each reconstruction according to their preference. There was disagreement among the six radiologists on which reconstruction produced images with the highest diagnostic content, but they preferred the midsharp/noise image appearance over the others. However, the reconstruction they preferred most did not match with their performance. Due to these disagreements, it may be difficult to develop a single image-based model observer that is representative of a population of radiologists for this particular imaging task.
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Affiliation(s)
- Juhun Lee
- University of Pittsburgh, Department of Radiology, Pittsburgh, Pennsylvania, United States
| | - Robert M Nishikawa
- University of Pittsburgh, Department of Radiology, Pittsburgh, Pennsylvania, United States
| | - Ingrid Reiser
- The University of Chicago, Department of Radiology, Chicago, Illinois, United States
| | - Margarita L Zuley
- University of Pittsburgh, Department of Radiology, Pittsburgh, Pennsylvania, United States
| | - John M Boone
- University of California Davis Medical Center, Department of Radiology, Sacramento, California, United States
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Lago MA, Abbey CK, Eckstein MP. Foveated Model Observers to predict human performance in 3D images. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2017; 10136. [PMID: 29176921 DOI: 10.1117/12.2252952] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We evaluate 3D search requires model observers that take into account the peripheral human visual processing (foveated models) to predict human observer performance. We show that two different 3D tasks, free search and location-known detection, influence the relative human visual detectability of two signals of different sizes in synthetic backgrounds mimicking the noise found in 3D digital breast tomosynthesis. One of the signals resembled a microcalcification (a small and bright sphere), while the other one was designed to look like a mass (a larger Gaussian blob). We evaluated current standard models observers (Hotelling; Channelized Hotelling; non-prewhitening matched filter with eye filter, NPWE; and non-prewhitening matched filter model, NPW) and showed that they incorrectly predict the relative detectability of the two signals in 3D search. We propose a new model observer (3D Foveated Channelized Hotelling Observer) that incorporates the properties of the visual system over a large visual field (fovea and periphery). We show that the foveated model observer can accurately predict the rank order of detectability of the signals in 3D images for each task. Together, these results motivate the use of a new generation of foveated model observers for predicting image quality for search tasks in 3D imaging modalities such as digital breast tomosynthesis or computed tomography.
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Affiliation(s)
- Miguel A Lago
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA. 93106, USA
| | - Craig K Abbey
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA. 93106, USA
| | - Miguel P Eckstein
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, CA. 93106, USA
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Chian TC, Nassir NM, Ibrahim MI, Yusof AKM, Sabarudin A. Quantitative assessment on coronary computed tomography angiography (CCTA) image quality: comparisons between genders and different tube voltage settings. Quant Imaging Med Surg 2017; 7:48-58. [PMID: 28275559 DOI: 10.21037/qims.2017.02.02] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND This study was carried out to quantify and compare the quantitative image quality of coronary computed tomography angiography (CCTA) between genders as well as between different tube voltages scan protocols. METHODS Fifty-five cases of CCTA were collected retrospectively and all images including reformatted axial images at systolic and diastolic phases as well as images with curved multi planar reformation (cMPR) were obtained. Quantitative image quality including signal intensity, image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of right coronary artery (RCA), left anterior descending artery (LAD), left circumflex artery (LCx) and left main artery (LM) were quantified using Analyze 12.0 software. RESULTS Six hundred and fifty-seven coronary arteries were evaluated. There were no significant differences in any quantitative image quality parameters between genders. 100 kilovoltage peak (kVp) scanning protocol produced images with significantly higher signal intensity compared to 120 kVp scanning protocol (P<0.001) in all coronary arteries in all types of images. Higher SNR was also observed in 100 kVp scan protocol in all coronary arteries except in LCx where 120 kVp showed better SNR than 100 kVp. CONCLUSIONS There were no significant differences in image quality of CCTA between genders and different tube voltages. Lower tube voltage (100 kVp) scanning protocol is recommended in clinical practice to reduce the radiation dose to patient.
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Affiliation(s)
- Teo Chee Chian
- Diagnostic Imaging & Radiotherapy Program, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia
| | - Norziana Mat Nassir
- Diagnostic Imaging & Radiotherapy Program, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia
| | - Mohd Izuan Ibrahim
- Diagnostic Imaging & Radiotherapy Program, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia
| | | | - Akmal Sabarudin
- Diagnostic Imaging & Radiotherapy Program, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia
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Wen G, Markey MK, Park S. Model observer design for multi-signal detection in the presence of anatomical noise. Phys Med Biol 2017; 62:1396-1415. [DOI: 10.1088/1361-6560/aa51e9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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47
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Wangerin KA, Ahn S, Wollenweber S, Ross SG, Kinahan PE, Manjeshwar RM. Evaluation of lesion detectability in positron emission tomography when using a convergent penalized likelihood image reconstruction method. J Med Imaging (Bellingham) 2016; 4:011002. [PMID: 27921073 DOI: 10.1117/1.jmi.4.1.011002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/18/2016] [Indexed: 11/14/2022] Open
Abstract
We have previously developed a convergent penalized likelihood (PL) image reconstruction algorithm using the relative difference prior (RDP) and showed that it achieves more accurate lesion quantitation compared to ordered subsets expectation maximization (OSEM). We evaluated the detectability of low-contrast liver and lung lesions using the PL-RDP algorithm compared to OSEM. We performed a two-alternative forced choice study using a channelized Hotelling observer model that was previously validated against human observers. Lesion detectability showed a stronger dependence on lesion size for PL-RDP than OSEM. Lesion detectability was improved using time-of-flight (TOF) reconstruction, with greater benefit for the liver compared to the lung and with increasing benefit for decreasing lesion size and contrast. PL detectability was statistically significantly higher than OSEM for 20 mm liver lesions when contrast was [Formula: see text] ([Formula: see text]), and TOF PL detectability was statistically significantly higher than TOF OSEM for 15 and 20 mm liver lesions with contrast [Formula: see text] and [Formula: see text], respectively. For all other cases, there was no statistically significant difference between PL and OSEM ([Formula: see text]). For the range of studied lesion properties, lesion detectability using PL-RDP was equivalent or improved compared to using OSEM.
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Affiliation(s)
- Kristen A Wangerin
- General Electric Global Research Center, 1 Research Circle, Niskayuna, New York 12309, United States; University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Sangtae Ahn
- General Electric Global Research Center , 1 Research Circle, Niskayuna, New York 12309, United States
| | - Scott Wollenweber
- General Electric Healthcare , 3000 North Grandview Boulevard, Waukesha, Wisconsin 53188, United States
| | - Steven G Ross
- General Electric Healthcare , 3000 North Grandview Boulevard, Waukesha, Wisconsin 53188, United States
| | - Paul E Kinahan
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195, United States; University of Washington, Department of Radiology, 1959 NE Pacific Street, Seattle, Washington 98195, United States
| | - Ravindra M Manjeshwar
- General Electric Global Research Center , 1 Research Circle, Niskayuna, New York 12309, United States
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Michielsen K, Nuyts J, Cockmartin L, Marshall N, Bosmans H. Design of a model observer to evaluate calcification detectability in breast tomosynthesis and application to smoothing prior optimization. Med Phys 2016; 43:6577. [DOI: 10.1118/1.4967268] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Han M, Park S, Baek J. Effect of anatomical noise on the detectability of cone beam CT images with different slice direction, slice thickness, and volume glandular fraction. OPTICS EXPRESS 2016; 24:18843-18859. [PMID: 27557168 DOI: 10.1364/oe.24.018843] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the effect of anatomical noise on the detectability of cone beam CT (CBCT) images with different slice directions, slice thicknesses, and volume glandular fractions (VGFs). Anatomical noise is generated using a power law spectrum of breast anatomy, and spherical objects with diameters from 1mm to 11mm are used as breast masses. CBCT projection images are simulated and reconstructed using the FDK algorithm. A channelized Hotelling observer (CHO) with Laguerre-Gauss (LG) channels is used to evaluate detectability for the signal-known-exactly (SKE) binary detection task. Detectability is calculated for various slice thicknesses in the transverse and longitudinal planes for 15%, 30% and 60% VGFs. The optimal slice thicknesses that maximize the detectability of the objects are determined. The results show that the β value increases as the slice thickness increases, but that thicker slices yield higher detectability in the transverse and longitudinal planes, except for the case of a 1mm diameter spherical object. It is also shown that the longitudinal plane with a 0.1mm slice thickness provides higher detectability than the transverse plane, despite its higher β value. With optimal slice thicknesses, the longitudinal plane exhibits better detectability for all VGFs and spherical objects.
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Park S, Zhang G, Myers KJ. Comparison of Channel Methods and Observer Models for the Task-Based Assessment of Multi-Projection Imaging in the Presence of Structured Anatomical Noise. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:1431-1442. [PMID: 26742128 DOI: 10.1109/tmi.2016.2515027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Although Laguerre-Gauss (LG) channels are often used for the task-based assessment of multi-projection imaging, LG channels may not be the most reliable in providing performance trends as a function of system or object parameters for all situations. Partial least squares (PLS) channels are more flexible in adapting to background and signal data statistics and were shown to be more efficient for detection tasks involving 2D non-Gaussian random backgrounds (Witten , 2010). In this work, we investigate ways of incorporating spatial correlations in the multi-projection data space using 2D LG channels and two implementations of PLS in the channelized version of the 3D projection Hotelling observer (Park , 2010) (3Dp CHO). Our task is to detect spherical and elliptical 3D signals in the angular projections of a structured breast phantom ensemble. The single PLS (sPLS) incorporates the spatial correlation within each projection, whereas the combined PLS (cPLS) incorporates the spatial correlations both within each of and across the projections. The 3Dp CHO-R indirectly incorporates the spatial correlation from the response space (R), whereas the 3Dp CHO-C from the channel space (C). The 3Dp CHO-R-sPLS has potential to be a good surrogate observer when either sample size is small or one training set is used for training both PLS channels and observer. So does the 3Dp CHO-C-cPLS when the sample size is large enough to have a good sized independent set for training PLS channels. Lastly a stack of 2D LG channels used as 3D channels in the CHO-C model showed the capability of incorporating the spatial correlation between the multiple angular projections.
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