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Watanabe S, Hirata K, Magota K, Takenaka J, Wakabayashi N, Shinyama D, Yasuda K, Homma A, Kudo K. Comparative study of physiological FDG uptake in small structures between silicon photomultiplier-based PET and conventional PET. Ann Nucl Med 2024; 38:131-138. [PMID: 37943379 DOI: 10.1007/s12149-023-01884-3] [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: 10/10/2023] [Accepted: 10/23/2023] [Indexed: 11/10/2023]
Abstract
OBJECTIVE Silicon photomultiplier-based positron emission tomography/computed tomography (SiPM-PET/CT) has the superior spatial resolution to conventional PET/CT (cPET/CT). This head-to-head comparison study compared the images of physiological 18F-fluorodeoxyglucose (FDG) accumulation in small-volume structures between SiPM-PET/CT and cPET/CT in patients scanned with both modalities, and we investigated whether the thresholds that are reported to be useful for differentiating physiological accumulations from malignant lesions can also be applied to SiPM-PET/CT. METHODS We enrolled 21 consecutive patients with head and neck malignancies who underwent whole-body FDG-PET/CT for initial staging or a follow-up evaluation (October 2020 to March 2022). After being injected with FDG, all patients underwent PET acquisition on both Vereos PET-CT and Gemini TF64 PET-CT systems (both Philips Healthcare) in random order. For each patient, the maximum standardized uptake value (SUVmax) was measured in the pituitary gland, esophagogastric junction (EGJ), adrenal glands, lumbar enlargement of the spinal cord, and epididymis. We measured the liver SUVmean and the blood pool SUVmean to calculate the target-to-liver ratio (TLR) and the target-to-blood ratio (TBR), respectively. Between-groups differences in each variable were examined by a paired t-test. We also investigated whether there were cases of target uptake greater than the reported threshold for distinguishing pathological from physiological accumulations. RESULTS Data were available for 19 patients. Ten patients were in Group 1, i.e., the patients who underwent SiPM-PET first, and the remaining nine patients who underwent cPET first were in Group 2. In the SiPM-PET results, the SUVmax of all targets was significantly higher than that obtained by cPET in all patients, and this tendency was also observed when the patients were divided into Groups 1/2. The TLRs of all targets were significantly higher in SiPM-PET than in cPET in all patients, and SiPM-PET also showed significantly higher TBRs for all targets except the EGJ (p = 0.052). CONCLUSIONS The physiological uptake in the small structures studied herein showed high accumulation on SiPM-PET. Our results also suggest that the thresholds reported for cPET to distinguish pathological accumulations likely lead to false-positive findings in SIPM-PET evaluations.
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Affiliation(s)
- Shiro Watanabe
- Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
- Department of Nuclear Medicine, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Kenji Hirata
- Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
- Department of Nuclear Medicine, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan.
- Division of Medical AI Education and Research, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
| | - Keiichi Magota
- Division of Medical Imaging and Technology, Hokkaido University Hospital, Sapporo, Japan
| | - Junki Takenaka
- Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
- Department of Nuclear Medicine, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | - Naoto Wakabayashi
- Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
- Department of Nuclear Medicine, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-Ku, Sapporo, Hokkaido, 060-8648, Japan
| | | | - Koichi Yasuda
- Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan
| | - Akihiro Homma
- Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kohsuke Kudo
- Department of Diagnostic Imaging, Hokkaido University Graduate School of Medicine, Kita 15 Nishi 7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
- Division of Medical AI Education and Research, Hokkaido University Graduate School of Medicine, Sapporo, Japan
- Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
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Maronnier Q, Robaine N, Chaltiel L, Dierickx LO, Cassou-Mounat T, Terroir M, Vija L, Vallot D, Brillouet S, Lamesa C, Filleron T, Caselles O, Courbon F. Insertion of synthetic lesions on patient data: a method for evaluating clinical performance differences between PET systems. EJNMMI Phys 2024; 11:9. [PMID: 38252388 PMCID: PMC10803700 DOI: 10.1186/s40658-023-00610-2] [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: 07/11/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND Performance assessment of positron emission tomography (PET) scanners is crucial to guide clinical practice with efficiency. We have already introduced and experimentally evaluated a simulation method allowing the creation of a controlled ground truth for system performance assessment. In the current study, the goal was to validate the method using patient data and demonstrate its relevance to assess PET performances accuracy in clinical conditions. METHODS Twenty-four patients were recruited and sorted into two groups according to their body mass index (BMI). They were administered with a single dose of 2 MBq/kg 18F-FDG and scanned using clinical protocols consecutively on two PET systems: the Discovery-IQ (DIQ) and the Discovery-MI (DMI). For each BMI group, sixty synthetic lesions were dispatched in three subgroups and inserted at relevant anatomical locations. Insertion of synthetic lesions (ISL) was performed at the same location into the two consecutive exams. Two nuclear medicine physicians evaluated individually and blindly the images by qualitatively and semi-quantitatively reporting each detected lesion and agreed on a consensus. We assessed the inter-system detection rates of synthetic lesions and compared it to an initial estimate of at least 1.7 more targets detected on the DMI and the detection rates of natural lesions. We determined the inter-reader variability, evaluated according to the inter-observer agreement (IOA). Adequate inter-reader variability was found for IOA above 80%. Differences in standardized uptake value (SUV) metrics were also studied. RESULTS In the BMI ≤ 25 group, the relative true positive rate (RTPR) for synthetic and natural lesions was 1.79 and 1.83, respectively. In the BMI > 25 group, the RTPR for synthetic and natural lesions was 2.03 and 2.27, respectively. For each BMI group, the detection rate using ISL was consistent to our estimate and with the detection rate measured on natural lesions. IOA above 80% was verified for any scenario. SUV metrics showed a good agreement between synthetic and natural lesions. CONCLUSIONS ISL proved relevant to evaluate performance differences between PET scanners. Using these synthetically modified clinical images, we can produce a controlled ground truth in a realistic anatomical model and exploit the potential of PET scanner for clinical purposes.
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Affiliation(s)
- Quentin Maronnier
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France.
| | - Nesrine Robaine
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Léonor Chaltiel
- Biostatistics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Lawrence O Dierickx
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Thibaut Cassou-Mounat
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Marie Terroir
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Lavinia Vija
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Delphine Vallot
- Medical Physics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Séverine Brillouet
- Radiopharmacy Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Chloé Lamesa
- Radiopharmacy Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Thomas Filleron
- Biostatistics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Olivier Caselles
- Medical Physics Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Frédéric Courbon
- Nuclear Medicine Department, Institut Claudius Regaud, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
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Yamaki T, Hatakeyama N, Murayama T, Funakura M, Hara T, Onodera S, Ito D, Yakufujiang M, Odaki M, Oka N, Kobayashi S. Prediction of voluntary movements of the upper extremities by resting state-brain regional glucose metabolism in patients with chronic severe brain injury: A pilot study. Hum Brain Mapp 2023; 44:3158-3167. [PMID: 36929226 PMCID: PMC10171500 DOI: 10.1002/hbm.26270] [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: 12/15/2022] [Accepted: 02/24/2023] [Indexed: 03/18/2023] Open
Abstract
Confirmation of the exact voluntary movements of patients with disorder of consciousness following severe traumatic brain injury (TBI) is difficult because of the associated communication disturbances. In this pilot study, we investigated whether regional brain glucose metabolism assessed by 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) at rest could predict voluntary movement in severe TBI patients, particularly those with sufficient upper limb capacity to use communication devices. We visually and verbally instructed patients to clasp or open their hands. After video capture, three independent rehabilitation therapists determined whether the patients' movements were voluntary or involuntary. The results were compared with the standardized uptake value in the primary motor cortex, referring to the Penfield's homunculus, by resting state by FDG-PET imaged 1 year prior. Results showed that glucose uptake in the left (p = 0.0015) and right (p = 0.0121) proximal limb of the primary motor cortex, based on Penfield's homunculus on cerebral cartography, may reflect contralateral voluntary movement. Receiver operating characteristic curve analysis showed that a mean cutoff standardized uptake value of 5.47 ± 0.08 provided the best sensitivity and specificity for differentiating between voluntary and involuntary movements in each area. FDG-PET may be a useful and robust biomarker for predicting long-term recovery of motor function in severe TBI patients with disorders of consciousness.
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Affiliation(s)
- Tomohiro Yamaki
- Division of Neurosurgery, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan.,Division of Radiology, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Naoya Hatakeyama
- Division of Rehabilitation, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Takemi Murayama
- Division of Rehabilitation, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Mika Funakura
- Division of Rehabilitation, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Takuya Hara
- Division of Rehabilitation, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Shinji Onodera
- Division of Radiology, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Daisuke Ito
- Division of Neurosurgery, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Maidinamu Yakufujiang
- Division of Neurosurgery, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Masaru Odaki
- Division of Neurosurgery, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Nobuo Oka
- Division of Neurosurgery, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan.,Division of Radiology, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
| | - Shigeki Kobayashi
- Division of Neurosurgery, Rehabilitation Center for Traumatic Apallics Chiba, National Agency for Automotive Safety and Victims' Aid, 3-30-1 Isobe, Mihama-ku, Chiba, 261-0012, Japan
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Bjöersdorff M, Puterman C, Oddstig J, Amidi J, Zackrisson S, Kjölhede H, Bjartell A, Wollmer P, Trägårdh E. Detection of lymph node metastases in patients with prostate cancer: Comparing conventional and digital [ 18 F]-fluorocholine PET-CT using histopathology as a reference. Clin Physiol Funct Imaging 2022; 42:381-388. [PMID: 35866190 DOI: 10.1111/cpf.12770] [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: 11/16/2021] [Revised: 05/12/2022] [Accepted: 05/31/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND Positron emission tomography-computed tomography (PET-CT) with [18 F]-fluorocholine (FCH) is used to detect and stage metastatic lymph nodes in patients with prostate cancer. Improvements to hardware and software have recently been made. We compared the capability of detecting regional lymph node metastases using conventional and digital silicon photomultiplier (SiPM)-based PET-CT technology for FCH. Extended pelvic lymph node dissection (ePLND) histopathology was used as a reference method. METHODS The study retrospectively examined 177 patients with intermediate or high-risk prostate cancer who had undergone staging with FCH PET-CT before ePLND. Images were obtained with either the conventional Philips Gemini PET-CT (n = 93) or the digital SiPM-based GE Discovery MI PET-CT (n = 84) and compared. RESULTS Images that were obtained using the Philips Gemini PET-CT system showed 19 patients (20%) with suspected lymph node metastases, whereas the GE Discovery MI PET-CT revealed 36 such patients (43%). The sensitivity, specificity, and positive and negative predictive values were 0.3, 0.84, 0.47, and 0.72 for the Philips Gemini, while they were 0.58, 0.62, 0.31, and 0.83 for the GE Discovery MI, respectively. The areas under the curves in a receiver operating characteristic curve analysis were similar between the two PET-CT systems (0.57 for Philips Gemini and 0.58 for GE Discovery MI, p = 0.89). CONCLUSIONS Marked differences in sensitivity and specificity were found for the different PET-CT systems, although the overall diagnostic performance was similar. These differences are probably due to differences in both hardware and software, including reconstruction algorithms, and should be considered when new technology is introduced.
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Affiliation(s)
- Mimmi Bjöersdorff
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Christopher Puterman
- Department of Urology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Jenny Oddstig
- Department of Clinical Physiology, Radiation Physics, Skåne University Hospital, Lund University, Lund, Sweden
| | - Jennifer Amidi
- Department of Urology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Sophia Zackrisson
- Department of Translational Medicine, Diagnostic Radiology, Lund University and Skåne University Hospital, Malmö, Sweden
| | - Henrik Kjölhede
- Department of Urology, Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Urology, Region Västra Götaland, Sahlgrenska University Hospital, Göteborg, Sweden
| | - Anders Bjartell
- Department of Urology, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Per Wollmer
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Lund University, Malmö, Sweden
| | - Elin Trägårdh
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Lund University, Malmö, Sweden.,Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
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Ingvar J, Hvittfeldt E, Trägårdh E, Simoulis A, Bjartell A. Assessing the accuracy of [ 18F]PSMA-1007 PET/CT for primary staging of lymph node metastases in intermediate- and high-risk prostate cancer patients. EJNMMI Res 2022; 12:48. [PMID: 35943665 PMCID: PMC9363552 DOI: 10.1186/s13550-022-00918-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022] Open
Abstract
Background [18F]PSMA-1007 is a promising tracer for integrated positron emission tomography and computed tomography (PET/CT).
Objective Our aim was to assess the diagnostic accuracy of [18F]PSMA-1007 PET/CT for primary staging of lymph node metastasis before robotic-assisted laparoscopy (RALP) with extended lymph node dissection (ePLND). Design, Setting and Participants The study was a retrospective cohort in a tertiary referral center. Men with prostate cancer that underwent surgical treatment for intermediate- or high-risk prostate cancer between May 2019 and August 2021 were included. Interventions [18F]PSMA-1007 PET/CT for initial staging followed by RALP and ePLND. Outcome measurements and statistical analyses Sensitivity and specificity were calculated both for the entire cohort and for patients with lymph node metastasis ≥ 3 mm. Positive (PPV) and negative (NPV) predictive values were calculated. Results and limitations Among 104 patients included in the analyses, 26 patients had lymph node metastasis based on pathology reporting and metastases were ≥ 3 mm in size in 13 of the cases (50%). In the entire cohort, the sensitivity and specificity of [18F]PSMA-1007 were 26.9% (95% confidence interval (CI); 11.6–47.8) and 96.2% (95% CI; 89.2–99.2), respectively. The sensitivity and specificity of [18F]PSMA-1007 to detect a lymph node metastasis ≥ 3 mm on PET/CT were 53.8% (95% CI; 25.1–80.8) and 96.7% (95% CI; 90.7–99.3), respectively. PPV was 70% and NPV 93.6%. Conclusions In primary staging of intermediate- and high-risk prostate cancer, [18F]PSMA-1007 PET/CT is highly specific for prediction of lymph node metastases, but the sensitivity for detection of metastases smaller than 3 mm is limited. Based on our results, [18F]PSMA-1007 PET/CT cannot completely replace ePLND. Patient summary This study investigated the use of an imaging method based on a prostate antigen-specific radiopharmaceutical tracer to detect lymph node prostate cancer metastasis. We found that it is unreliable to discover small metastasis.
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Affiliation(s)
- Jacob Ingvar
- Department of Urology, Skåne University Hospital, Malmö, Sweden. .,Department of Translational Medicine, Faculty of Medicine, Lund University, Jan Waldenströmsgata 5, 205 02, Malmö, Sweden.
| | - Erland Hvittfeldt
- Department of Translational Medicine, Faculty of Medicine, Lund University, Jan Waldenströmsgata 5, 205 02, Malmö, Sweden.,Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Malmö, Sweden.,Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Elin Trägårdh
- Department of Translational Medicine, Faculty of Medicine, Lund University, Jan Waldenströmsgata 5, 205 02, Malmö, Sweden.,Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Malmö, Sweden.,Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Athanasios Simoulis
- Department of Translational Medicine, Faculty of Medicine, Lund University, Jan Waldenströmsgata 5, 205 02, Malmö, Sweden.,Department of Pathology, Skåne University Hospital and Lund University, Malmö, Sweden
| | - Anders Bjartell
- Department of Urology, Skåne University Hospital, Malmö, Sweden.,Department of Translational Medicine, Faculty of Medicine, Lund University, Jan Waldenströmsgata 5, 205 02, Malmö, Sweden
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Bailly P, Bouzerar R, Galan R, Meyer ME. Phantom study of an in-house amplitude-gating respiratory method with silicon photomultiplier technology positron emission tomography/computed tomography. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106907. [PMID: 35660941 DOI: 10.1016/j.cmpb.2022.106907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
PURPOSE The objective of this phantom study was to determine whether breathing-synchronized, silicon photomultiplier (SiPM)-based PET/CT has a suitable acquisition time for routine clinical use. METHODS Acquisitions were performed in list mode on a 4-ring SiPM-based PET/CT system. The experimental setup consisted of an external respiratory tracking device placed on a commercial dynamic thorax phantom containing a sphere filled with [F-18]-fluorodeoxyglucose. Three-dimensional sinusoidal motion was imposed on the sphere. Data were processed using frequency binning and amplitude binning (the "DMI" and "OFFLINE" methods, respectively). PET sinograms were reconstructed with a Bayesian penalized likelihood algorithm. RESULTS Respiratory gating from a 150‑sec acquisition was successful. The DMI and OFFLINE methods gave similar activity profiles but both were slightly shifted in space; the latter profile was closest to the reference acquisition. CONCLUSION With SiPM PET/CT systems, the amplitude-based processing of breathing-synchronized data is likely to be feasible in routine clinical practice.
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Affiliation(s)
- Pascal Bailly
- Nuclear Medicine Department, Amiens University Medical Center, Amiens, France; Department of Nuclear Medicine, Amiens University Hospital, Amiens, France.
| | - Roger Bouzerar
- Nuclear Medicine Department, Amiens University Medical Center, Amiens, France; Department of Nuclear Medicine, Amiens University Hospital, Amiens, France
| | - Romain Galan
- Nuclear Medicine Department, Amiens University Medical Center, Amiens, France; Jules Verne University of Picardie, Amiens, France; Department of Nuclear Medicine, Amiens University Hospital, Amiens, France
| | - Marc-Etienne Meyer
- Nuclear Medicine Department, Amiens University Medical Center, Amiens, France; Jules Verne University of Picardie, Amiens, France; Department of Nuclear Medicine, Amiens University Hospital, Amiens, France
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Trägårdh E, Enqvist O, Ulén J, Hvittfeldt E, Garpered S, Belal SL, Bjartell A, Edenbrandt L. Freely available artificial intelligence for pelvic lymph node metastases in PSMA PET-CT that performs on par with nuclear medicine physicians. Eur J Nucl Med Mol Imaging 2022; 49:3412-3418. [PMID: 35475912 PMCID: PMC9308591 DOI: 10.1007/s00259-022-05806-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 04/16/2022] [Indexed: 01/25/2023]
Abstract
PURPOSE The aim of this study was to develop and validate an artificial intelligence (AI)-based method using convolutional neural networks (CNNs) for the detection of pelvic lymph node metastases in scans obtained using [18F]PSMA-1007 positron emission tomography-computed tomography (PET-CT) from patients with high-risk prostate cancer. The second goal was to make the AI-based method available to other researchers. METHODS [18F]PSMA PET-CT scans were collected from 211 patients. Suspected pelvic lymph node metastases were marked by three independent readers. A CNN was developed and trained on a training and validation group of 161 of the patients. The performance of the AI method and the inter-observer agreement between the three readers were assessed in a separate test group of 50 patients. RESULTS The sensitivity of the AI method for detecting pelvic lymph node metastases was 82%, and the corresponding sensitivity for the human readers was 77% on average. The average number of false positives was 1.8 per patient. A total of 5-17 false negative lesions in the whole cohort were found, depending on which reader was used as a reference. The method is available for researchers at www.recomia.org . CONCLUSION This study shows that AI can obtain a sensitivity on par with that of physicians with a reasonable number of false positives. The difficulty in achieving high inter-observer sensitivity emphasizes the need for automated methods. On the road to qualifying AI tools for clinical use, independent validation is critical and allows performance to be assessed in studies from different hospitals. Therefore, we have made our AI tool freely available to other researchers.
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Affiliation(s)
- Elin Trägårdh
- Department of Translational Medicine and Wallenberg Centre of Molecular Medicine, Lund University, Malmö, Sweden.
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Carl Bertil Laurells gata 9, 205 02, Malmö, Sweden.
| | - Olof Enqvist
- Eigenvision AB, Malmö, Sweden
- Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Erland Hvittfeldt
- Department of Translational Medicine and Wallenberg Centre of Molecular Medicine, Lund University, Malmö, Sweden
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Carl Bertil Laurells gata 9, 205 02, Malmö, Sweden
| | - Sabine Garpered
- Department of Clinical Physiology and Nuclear Medicine, Skåne University Hospital, Carl Bertil Laurells gata 9, 205 02, Malmö, Sweden
| | - Sarah Lindgren Belal
- Department of Translational Medicine and Wallenberg Centre of Molecular Medicine, Lund University, Malmö, Sweden
- Department of Surgery, Skåne University Hospital, Malmö, Sweden
| | - Anders Bjartell
- Department of Urology, Skåne University Hospital and Lund University, Malmö, Sweden
| | - Lars Edenbrandt
- Department of Clinical Physiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Menendez MI, Moore RR, Abdel-Rasoul M, Wright CL, Fernandez S, Jackson RD, Knopp MV. [ 18F] Sodium Fluoride Dose Reduction Enabled by Digital Photon Counting PET/CT for Evaluation of Osteoblastic Activity. Front Med (Lausanne) 2022; 8:725118. [PMID: 35096851 PMCID: PMC8789749 DOI: 10.3389/fmed.2021.725118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 12/17/2021] [Indexed: 11/24/2022] Open
Abstract
The aim of the study was to assess the quality and reproducibility of reducing the injected [18F] sodium fluoride ([18F]NaF) dose while maintaining diagnostic imaging quality in bone imaging in a preclinical skeletal model using digital photon counting PET (dPET) detector technology. Beagles (n = 9) were administered three different [18F]NaF doses: 111 MBq (n = 5), 20 MBq (n = 5), and 1.9 MBq (n = 9). Imaging started ≃45 min post-injection for ≃30 min total acquisition time. Images were reconstructed using Time-of-Flight, ultra-high definition (voxel size of 1 × 1 × 1 mm3), with 3 iterations and 3 subsets. Point spread function was modeled and Gaussian filtering was applied. Skeleton qualitative and quantitative molecular image assessment was performed. The overall diagnostic quality of all images scored excellent (61%) and acceptable (39%) by all the reviewers. [18F]NaF SUVmean showed no statistically significant differences among the three doses in any of the region of interest assessed. This study demonstrated that a 60-fold [18F]NaF dose reduction was not significantly different from the highest dose, and it had not significant effect on overall image quality and quantitative accuracy. In the future, ultra-low dose [18F]NaF dPET/CT imaging may significantly decrease PET radiation exposure to preclinical subjects and personnel.
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Affiliation(s)
- Maria I Menendez
- Department of Radiology, The Wright Center of Innovation in Biomedical Imaging, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Richard R Moore
- Department of Radiology, The Wright Center of Innovation in Biomedical Imaging, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Mahmoud Abdel-Rasoul
- Center for Biostatistics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Chadwick L Wright
- Department of Radiology, The Wright Center of Innovation in Biomedical Imaging, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Soledad Fernandez
- Center for Biostatistics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Rebecca D Jackson
- Department of Internal Medicine, Endocrinology, Diabetes and Metabolism, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Michael V Knopp
- Department of Radiology, The Wright Center of Innovation in Biomedical Imaging, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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Oddstig J, Brolin G, Trägårdh E, Minarik D. Head-to-head comparison of a Si-photomultiplier-based and a conventional photomultiplier-based PET-CT system. EJNMMI Phys 2021; 8:19. [PMID: 33630173 PMCID: PMC7907292 DOI: 10.1186/s40658-021-00366-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 02/09/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND A novel generation of PET scanners based on silicon (Si)-photomultiplier (PM) technology has recently been introduced. Concurrently, there has been development of new reconstruction methods aimed at increasing the detectability of small lesions without increasing image noise. The combination of new detector technologies and new reconstruction algorithms has been found to increase image quality. However, it is unknown to what extent the demonstrated improvement of image quality is due to scanner hardware development or improved reconstruction algorithms. To isolate the contribution of the hardware, this study aimed to compare the ability to detect small hotspots in phantoms using the latest generation SiPM-based PET/CT scanner (GE Discovery MI) relative to conventional PM-based PET/CT scanner (GE Discovery 690), using identical reconstruction protocols. MATERIALS AND METHODS Two different phantoms (NEMA body and Jasczcak) with fillable spheres (31 μl to 26.5 ml) and varying sphere-to-background-ratios (SBR) were scanned in one bed position for 15-600 s on both scanners. The data were reconstructed using identical reconstruction parameters on both scanners. The recovery-coefficient (RC), noise level, contrast (spherepeak/backgroundpeak-value), and detectability of each sphere were calculated and compared between the scanners at each acquisition time. RESULTS The RC-curves for the NEMA phantom were near-identical for both scanners at SBR 10:1. For smaller spheres in the Jaszczak phantom, the contrast was 1.22 higher for the DMI scanner at SBR 15:1. The ratio decreased for lower SBR, with a ratio of 1.03 at SBR 3.85:1. Regarding the detectability of spheres, the sensitivity was 98% and 88% for the DMI and D690, respectively, for SBR 15:1. For SBR 7.5, the sensitivity was 75% and 83% for the DMI and D690, respectively. For SBR 3.85:1, the sensitivity was 43% and 30% for the DMI and D690, respectively. CONCLUSION Marginally higher contrast in small spheres was seen for the SiPM-based scanner but there was no significant difference in detectability between the scanners. It was difficult to detect differences between the scanners, suggesting that the SiPM-based detectors are not the primary reason for improved image quality.
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Affiliation(s)
- Jenny Oddstig
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, 221 85, Lund, Sweden.
| | - Gustav Brolin
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, 221 85, Lund, Sweden
| | - Elin Trägårdh
- Clinical Physiology and Nuclear Medicine, Skåne University Hospital and Lund University, Carl Bertil Laurells gata 9, Skåne University Hospital, 205 02, Malmö, Sweden.,Wallenberg Center for Molecular Medicine, Lund University, Carl Bertil Laurells gata 9, Skåne University Hospital, 205 02, Malmö, Sweden
| | - David Minarik
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, 221 85, Lund, Sweden
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Leccisotti L, Lorusso M, Feudo V, Gremese E, Giordano A. Diagnostic performance of FDG PET in large vessel vasculitis. Clin Transl Imaging 2019. [DOI: 10.1007/s40336-019-00349-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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