Mr. Md Ashequr Rahman Profile

Md Ashequr Rahman

at Washington Univ in St. Louis

Publications (6)

Proceedings Article | 29 March 2024 Presentation + Paper

Can patient-specific acquisition protocol improve performance on defect detection task in myocardial perfusion SPECT?

Nu Ri Choi, Md Ashequr Rahman, Zitong Yu, Barry Siegel, Abhinav Jha

Proceedings Volume 12929, 129290O (2024) https://doi.org/10.1117/12.3006924

KEYWORDS: Anatomy, Defect detection, Medical image reconstruction, Information operations, Single photon emission computed tomography, Breast, Computed tomography, Perfusion imaging, Image quality, Design

Read Abstract +

Myocardial perfusion imaging using single-photon emission computed tomography (SPECT), or myocardial perfusion SPECT (MPS) is a widely used clinical imaging modality for the diagnosis of coronary artery disease. Current clinical protocols for acquiring and reconstructing MPS images are similar for most patients. However, for patients with outlier anatomical characteristics, such as large breasts, images acquired using conventional protocols are often sub-optimal in quality, leading to degraded diagnostic accuracy. Solutions to improve image quality for these patients outside of increased dose or total acquisition time remain challenging. Thus, there is an important need for new methodologies that can help improve the quality of the acquired images for such patients, in terms of the ability to detect myocardial perfusion defects. One approach to improving this performance is adapting the image acquisition protocol specific to each patient. Studies have shown that in MPS, different projection angles usually contain varying amounts of information for the detection task. However, current clinical protocols spend the same time at each projection angle. In this work, we evaluated whether an acquisition protocol that is optimized for each patient could improve performance on the task of defect detection on reconstructed images for patients with outlier anatomical characteristics. For this study, we first designed and implemented a personalized patient-specific protocol-optimization strategy, which we term precision SPECT (PRESPECT). This strategy integrates the theory of ideal observers with the constraints of tomographic reconstruction to optimize the acquisition time for each projection view, such that performance on the task of detecting myocardial perfusion defects is maximized. We performed a clinically realistic simulation study on patients with outlier anatomies on the task of detecting perfusion defects on various realizations of low-dose scans by an anthropomorphic channelized Hotelling observer. Our results show that using PRESPECT led to improved performance on the defect detection task for the considered patients. These results provide evidence that personalization of MPS acquisition protocol has the potential to improve defect detection performance on reconstructed images by anthropomorphic observers for patients with outlier anatomical characteristics. Thus, our findings motivate further research to design optimal patient-specific acquisition and reconstruction protocols for MPS, as well as developing similar approaches for other medical imaging modalities.

Proceedings Article | 7 April 2023 Presentation + Paper

Development and task-based evaluation of a scatter-window projection and deep learning-based transmission-less attenuation compensation method for myocardial perfusion SPECT

Zitong Yu, Md Ashequr Rahman, Craig Abbey, Barry Siegel, Abhinav Jha

Proceedings Volume 12463, 124631E (2023) https://doi.org/10.1117/12.2654500

KEYWORDS: Single photon emission computed tomography, Signal attenuation, Computed tomography, Image segmentation, Medical image reconstruction, Attenuation, Defect detection

Read Abstract +

Proceedings Article | 3 April 2023 Poster + Paper

A task-specific deep-learning-based denoising approach for myocardial perfusion SPECT

Ashequr Rahman, Zitong Yu, Barry Siegel, Abhinav Jha

Proceedings Volume 12467, 1246719 (2023) https://doi.org/10.1117/12.2655629

KEYWORDS: Denoising, Single photon emission computed tomography, Defect detection, Image processing, Image filtering, Visual system, Artificial intelligence, Deep learning

Read Abstract +

Proceedings Article | 4 April 2022 Presentation + Paper

Investigating the limited performance of a deep-learning-based SPECT denoising approach: an observer-study-based characterization

Zitong Yu, Md. Ashequr Rahman, Abhinav Jha

Proceedings Volume 12035, 120350D (2022) https://doi.org/10.1117/12.2613134

KEYWORDS: Denoising, Single photon emission computed tomography, Signal detection, Medical imaging, Defect detection, Nuclear medicine, Imaging systems, Signal processing

Read Abstract +

Multiple objective assessment of image-quality (OAIQ)-based studies have reported that several deep-learning (DL)-based denoising methods show limited performance on signal-detection tasks. Our goal was to investigate the reasons for this limited performance. To achieve this goal, we conducted a task-based characterization of a DLbased denoising approach for individual signal properties. We conducted this study in the context of evaluating a DL-based approach for denoising single photon-emission computed tomography (SPECT) images. The training data consisted of signals of different sizes and shapes within a clustered-lumpy background, imaged with a 2D parallel-hole-collimator SPECT system. The projections were generated at normal and 20% low-dose level, both of which were reconstructed using an ordered-subset-expectation-maximization (OSEM) algorithm. A convolutional neural network (CNN)-based denoiser was trained to denoise the low-dose images. The performance of this CNN was characterized for five different signal sizes and four different signal-to-background ratio (SBRs) by designing each evaluation as a signal-known-exactly/background-known-statistically (SKE/BKS) signal-detection task. Performance on this task was evaluated using an anthropomorphic channelized Hotelling observer (CHO). We observed that the DL-based denoising approach did not improve performance on the signal-detection task for any of the signal types. None of signal types did the DL-based denoising approach improve performance. Further investigations revealed a drop in the mean of the differences between the signal-present and the signal-absent images, resulting in this limited performance on detection tasks. Additionally, it was observed that evaluation with fidelity-based figures of merit (root mean square error and structural similarity index) directly contradicted the observer study findings for all signals. Overall, these results provide new insights on the performance of the DL-based denoising approach as a function of signal size and contrast. More generally, the observer study-based characterization provides a mechanism to evaluate the sensitivity of the method to specific object properties, and may be explored as analogous to characterizations such as modulation transfer function for linear systems. Finally, this work underscores the need for objective task-based evaluation of DL-based denoising approaches.

Proceedings Article | 15 February 2021 Presentation + Paper

Task-based assessment of binned and list-mode SPECT systems

Md Ashequr Rahman, Abhinav Jha

Proceedings Volume 11599, 1159904 (2021) https://doi.org/10.1117/12.2582266

KEYWORDS: Single photon emission computed tomography, Imaging systems, Data acquisition, Yield improvement, Signal detection, Reconstruction algorithms, Expectation maximization algorithms, Error analysis, Binary data

Read Abstract +

Proceedings Article | 15 February 2021 Presentation + Paper

A physics and learning-based transmission-less attenuation compensation method for SPECT

Zitong Yu, Md Ashequr Rahman, Thomas Schindler, Richard Laforest, Abhinav Jha

Proceedings Volume 11595, 1159512 (2021) https://doi.org/10.1117/12.2582350

KEYWORDS: Signal attenuation, Single photon emission computed tomography, Physics, Computed tomography, Visualization, Brain mapping, Photons, Image segmentation, Defect detection, Data acquisition

Read Abstract +

Showing 5 of 6 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years