1
|
Shirakawa Y, Matsutomo N. Impact of list-mode reconstruction and image-space point spread function correction on PET image contrast and quantitative value using SiPM-based PET/CT system. Radiol Phys Technol 2023; 16:384-396. [PMID: 37368168 DOI: 10.1007/s12194-023-00729-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023]
Abstract
We evaluate the effects of list-mode reconstruction and the image-space point spread function (iPSF) on the contrast and quantitative values of positron emission tomography (PET) images using a SiPM-PET/CT system. The evaluation is conducted on an NEMA body phantom and clinical images using a Cartesion Prime SiPM-PET/CT system. The signal-to-background ratio (SBR) of the phantom is set to 2, 4, 6, and 8, and all the PET image data are obtained and reconstructed using 3D-OSEM, time-of-flight, iPSF (-/ +), and a 4-mm Gaussian filter with several iterations. The evaluation criteria include % background variability (NB,10 mm), % contrast (QH,10 mm), iPSF change in QH,10 mm (ΔQH,10 mm) for edge artifact evaluation, profile curves, visual evaluation of edge artifacts, clinical imaging for the standardized uptake value (SUV) of lung nodules, and SNRliver. NB,10 mm demonstrates no significant difference in all SBRs with and without iPSF, whereas QH,10 mm is higher based on the SBR with and without iPSF. ΔQH,10 mm indicates increased iterations and a larger rate of change (> 5%) for small spheres of < 17 mm. The profile curves portrayed almost real concentrations, except for the 10-mm sphere of SBR2 without iPSF; however, with iPSF, an overshoot was observed in the 13-mm sphere of all SBRs. The degree of overshoot increased with increasing iteration and SBR. Edge artifacts were detected at values ≥ 17-22 mm in SBRs other than SBR2 with iPSF. Irrespective of the nodal size, SUV and SNRliver improved considerably after iPSF adjustment. Therefore, the effects of list-mode reconstruction and iPSF on PET image contrast were limited, and the overcorrection of the quantitative values was validated using iPSF.
Collapse
Affiliation(s)
- Yuya Shirakawa
- Department of Radiology, Kyorin University Hospital, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.
| | - Norikazu Matsutomo
- Department of Medical Radiological Technology, Faculty of Health Sciences, Kyorin University, Mitaka, Tokyo, 181-8612, Japan
| |
Collapse
|
2
|
Tiss A, Marin T, Chemli Y, Spangler-Bickell MG, Gong K, Lois C, Petibon Y, Landes V, Grogg K, Normandin M, Becker A, Thibault E, Johnson K, El Fakhri G, Ouyang J. Impact of motion correction on [ 18F]-MK6240 tau PET imaging. Phys Med Biol 2023; 68. [PMID: 37116511 DOI: 10.1088/1361-6560/acd161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 04/28/2023] [Indexed: 04/30/2023]
Abstract
OBJECTIVE PET imaging of tau deposition using [18F]-MK6240 often involves long acquisitions in older subjects, many of whom exhibit dementia symptoms. The resulting unavoidable head motion can greatly degrade image quality. Motion increases the variability of PET quantitation for longitudinal studies across subjects, resulting in larger sample sizes in clinical trials of Alzheimer's disease (AD) treatment.
Approach: After using an ultra-short frame-by-frame motion detection method based on the list-mode data, we applied an event-by-event list-mode reconstruction to generate the motion-corrected images from 139 scans acquired in 65 subjects. This approach was initially validated in two phantoms experiments against optical tracking data. We developed a motion metric based on the average voxel displacement in the brain to quantify the level of motion in each scan and consequently evaluate the effect of motion correction on images from studies with substantial motion. We estimated the rate of tau accumulation in longitudinal studies (51 subjects) by calculating the difference in the ratio of standard uptake values in key brain regions for AD. We compared the regions' standard deviations across subjects from motion and non-motion corrected images.
Main Results: Individually, 14% of the scans exhibited notable motion quantified by the proposed motion metric, affecting 48% of the longitudinal datasets with three time points and 25% of all subjects. Motion correction decreased the blurring in images from scans with notable motion and improved the accuracy in quantitative measures. Motion correction reduced the standard deviation of the rate of tau accumulation by -49%, -24%, -18%, and -16% in the entorhinal, inferior temporal, precuneus, and amygdala regions, respectively. 
Significance: The list-mode-based motion correction method is capable of correcting both fast and slow motion during brain PET scans. It leads to improved brain PET quantitation, which is crucial for imaging AD.
Collapse
Affiliation(s)
- Amal Tiss
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Thibault Marin
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Yanis Chemli
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | | | - Kuang Gong
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Cristina Lois
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Yoann Petibon
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Vanessa Landes
- GE Healthcare, Boston, Boston, Massachusetts, 02114, UNITED STATES
| | - Kira Grogg
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Marc Normandin
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Alex Becker
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Emma Thibault
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Keith Johnson
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| | - Jinsong Ouyang
- Gordon Center for Medical Imaging, Department of Imaging, Massachusetts General Hospital, 125 Nashua St, Boston, Massachusetts, 02114-2696, UNITED STATES
| |
Collapse
|