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Overbeck N, Ahangari S, Conti M, Panin V, Azam A, Kurbegovic S, Kjær A, Højgaard L, Korsholm K, Fischer BM, Andersen FL, Andersen TL. Improved Positron Emission Tomography Quantification: Evaluation of a Maximum-Likelihood Scatter Scaling Algorithm. Diagnostics (Basel) 2024; 14:1075. [PMID: 38893602 PMCID: PMC11172368 DOI: 10.3390/diagnostics14111075] [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: 04/23/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
Incorrect scatter scaling of positron emission tomography (PET) images can lead to halo artifacts, quantitative bias, or reconstruction failure. Tail-fitted scatter scaling (TFSS) possesses performance limitations in multiple cases. This study aims to investigate a novel method for scatter scaling: maximum-likelihood scatter scaling (MLSS) in scenarios where TFSS tends to induce artifacts or are observed to cause reconstruction abortion. [68Ga]Ga-RGD PET scans of nine patients were included in cohort 1 in the scope of investigating the reduction of halo artifacts relative to the scatter estimation method. PET scans of 30 patients administrated with [68Ga]Ga-uPAR were included in cohort 2, used for an evaluation of the robustness of MLSS in cases where TFSS-integrated reconstructions are observed to fail. A visual inspection of MLSS-corrected images scored higher than TFSS-corrected reconstructions of cohort 1. The quantitative investigation near the bladder showed a relative difference in tracer uptake of up to 94.7%. A reconstruction of scans included in cohort 2 resulted in failure in 23 cases when TFSS was used. The lesion uptake values of cohort 2 showed no significant difference. MLSS is suggested as an alternative scatter-scaling method relative to TFSS with the aim of reducing halo artifacts and a robust reconstruction process.
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Affiliation(s)
- Nanna Overbeck
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
| | - Sahar Ahangari
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
| | - Maurizio Conti
- Siemens Medical Solutions Inc., Knoxville, TN 37932, USA; (M.C.); (V.P.)
| | - Vladimir Panin
- Siemens Medical Solutions Inc., Knoxville, TN 37932, USA; (M.C.); (V.P.)
| | - Aleena Azam
- Cluster for Molecular Imaging, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (A.A.); (S.K.)
- Department of Biomedical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Department of Neurosurgery, Neuroscience Center, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark
| | - Sorel Kurbegovic
- Cluster for Molecular Imaging, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (A.A.); (S.K.)
- Department of Biomedical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Andreas Kjær
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
- Cluster for Molecular Imaging, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (A.A.); (S.K.)
- Department of Biomedical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Liselotte Højgaard
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
| | - Kirsten Korsholm
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
| | - Barbara Malene Fischer
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
| | - Flemming Littrup Andersen
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
| | - Thomas Lund Andersen
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital—Rigshospitalet, 2100 Copenhagen, Denmark; (N.O.); (A.K.); (L.H.); (K.K.); (B.M.F.); (F.L.A.)
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Adiyat KT, Pooleri GK, Cherian DT, Santhamma SGN, Ravichandran K, Sundaram S. Negative predictive value of PSMA PET scan for lymph node staging in patients undergoing robotic radical prostatectomy and pelvic lymph node dissection. Int Urol Nephrol 2023; 55:1453-1457. [PMID: 37086333 DOI: 10.1007/s11255-023-03595-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/09/2023] [Indexed: 04/23/2023]
Abstract
PURPOSE To assess the negative predictive value of PSMA PET scan for lymph node staging in patients undergoing robotic radical prostatectomy and pelvic lymph node dissection. MATERIALS AND METHODS A retrospective analysis of patients who underwent robotic-assisted radical prostatectomy with pelvic lymph node dissection and had a preoperative negative PSMA PET scan for metastasis was performed. The documented pre-operative variables studied included age, BMI, PSA at diagnosis, Gleason score, and biopsy ISUP grades. Patients were categorised as low, intermediate and high risk according to the D Amico classification. The post-op variables included were number of lymph nodes harvested, number of positive nodes, positivity rate, size of the node metastasis, T staging and ISUP grading. RESULTS The overall negative predictive value of PSMA PET scan was 71.6%. Further sub-classification according to risk stratification demonstrated a NPV of 58.02%, 92.7% and 90% for high, intermediate and low risk, respectively. CONCLUSION Pelvic lymph node dissection cannot be excluded based on a negative preop PSMA PET/CT scan.
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Affiliation(s)
- Kishore Thekke Adiyat
- Aster Medcity, Kochi, India.
- Department of Urology, Aster Medcity, Kuttisahib Road, Cheranelloor, Ernakulam, Kerala, 682027, India.
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Hu C, Dong L, Xue W, Pienta KJ. Prostate-Specific Membrane Antigen-Based PET Brings New Insights into the Management of Prostate Cancer. PET Clin 2022; 17:555-564. [PMID: 36153235 DOI: 10.1016/j.cpet.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Prostate cancer (PCa) is the third most common cancer diagnosed in the world. Since its first identification in 1987 and its first molecular cloning in 1993, prostate-specific membrane antigen (PSMA) has been developed as a theragnostic imaging biomarker and therapeutic agent for PCa. For metastatic castration-resistant PCa, PSMA-based PET imaging can be applied to the monitoring of disease and response assessment with PSMA-based therapeutics. This novel imaging modality is bringing new insights into diagnosis, stratification, and clinical decision-making and treatment.
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Affiliation(s)
- Cong Hu
- Department of Urology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, 160 Pujian Road, Shanghai 200127, China
| | - Liang Dong
- Department of Urology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, 160 Pujian Road, Shanghai 200127, China
| | - Wei Xue
- Department of Urology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, 160 Pujian Road, Shanghai 200127, China
| | - Kenneth J Pienta
- Department of Urology, The James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA.
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Bogdanovic B, Solari EL, Villagran Asiares A, McIntosh L, van Marwick S, Schachoff S, Nekolla SG. PET/MR Technology: Advancement and Challenges. Semin Nucl Med 2021; 52:340-355. [PMID: 34969520 DOI: 10.1053/j.semnuclmed.2021.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 01/07/2023]
Abstract
When this article was written, it coincided with the 11th anniversary of the installation of our PET/MR device in Munich. In fact, this was the first fully integrated device to be in clinical use. During this time, we have observed many interesting behaviors, to put it kindly. However, it is more critical that in this process, our understanding of the system also improved - including the advantages and limitations from a technical, logistical, and medical perspective. The last decade of PET/MRI research has certainly been characterized by most sites looking for a "key application." There were many ideas in this context and before and after the devices became available, some of which were based on the earlier work with integrating data from single devices. These involved validating classical PET methods with MRI (eg, perfusion or oncology diagnostics). More important, however, were the scenarios where intermodal synergies could be expected. In this review, we look back on this decade-long journey, at the challenges overcome and those still to come.
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Affiliation(s)
- Borjana Bogdanovic
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Esteban Lucas Solari
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Alberto Villagran Asiares
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Lachlan McIntosh
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - Sandra van Marwick
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sylvia Schachoff
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Stephan G Nekolla
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany.
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Reduced Acquisition Time per Bed Position for PET/MRI Using 68Ga-RM2 or 68Ga-PSMA-11 in Patients With Prostate Cancer: A Retrospective Analysis. AJR Am J Roentgenol 2021; 218:333-340. [PMID: 34406051 DOI: 10.2214/ajr.21.25961] [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] [Indexed: 12/20/2022]
Abstract
BACKGROUND. Growing clinical adoption of PET/MRI for prostate cancer (PC) evaluation has increased interest in reducing PET/MRI scanning times. Reducing acquisition time per bed position below current times of at least 5 minutes would allow shorter examination lengths. OBJECTIVE. The purpose of this study was to evaluate the effect of different reduced PET acquisition times in patients with PC who underwent 68Ga-PSMA-11 or 68Ga-RM2 PET/MRI using highly sensitive silicon photomultiplier-based PET detectors. METHODS. This study involved retrospective review of men with PC who underwent PET/MRI as part of one of two prospective trials. Fifty men (mean [± SD] age, 69.9 ± 6.8 years) who underwent 68Ga-RM2 PET/MRI and 50 men (mean age, 66.6 ± 5.7 years) who underwent 68Ga-PSMA-11 PET/MRI were included. PET/MRI used a time-of-flight-enabled system with silicon photomultiplier-based detectors. The acquisition time was 4 minutes per bed position. PET data were reconstructed using acquisition times of 30 seconds, 1 minute, 2 minutes, 3 minutes, and 4 minutes. Three readers independently assessed image quality for each reconstruction using a 5-point Likert scale (with 1 denoting nondiagnostic and 5 indicating excellent quality). One reader measured SUVmax for up to six lesions per patient. Two readers independently assessed lesion conspicuity using a a 3-point Likert scale (with 1 indicating that lesions were not visualized and 3 denoting that they were definitely visualized). RESULTS. Mean image quality across readers at 30 seconds, 1 minutes, 2 minutes, 3 minutes, and 4 minutes was, for 68Ga-RM2 PET/MRI, from 1.0 ± 0.2 to 1.7 ± 0.7, 2.0 ± 0.3 to 2.6 ± 0.8, 3.1 ± 0.5 to 3.9 ± 0.8, 4.6 ± 0.6 to 4.7 ± 0.6, and 4.8 ± 0.4 to 4.8 ± 0.5, respectively, and for 68Ga-PSMA-11 PET/MRI it was from 1.2 ± 0.4 to 1.8 ± 0.6, 2.2 ± 0.4 to 2.8 ± 0.7, 3.6 ± 0.6 to 4.1± 0.8, 4.8 ± 0.4 to 4.9 ± 0.4, and 4.9 ± 0.3 to 5.0 ± 0.2, respectively. The mean lesion SUVmax for 68Ga-RM2 PET/MRI was 11.1 ± 12.4, 10.2 ± 11.7, 9.6 ± 11.3, 9.5 ± 11.6, and 9.4 ± 11.6, respectively, and for 68Ga-PSMA-11 PET/MRI it was 14.7 ± 8.2, 12.9 ± 7.4, 12.1 ± 7.8, 11.7 ± 7.9, and 11.6 ± 7.9, respectively. Mean lesion conspicuity (reader 1/reader 2) was, for 68Ga-RM2 PET/MRI, 2.4 ± 0.5/2.7 ± 0.5, 2.9 ± 0.3/2.9 ± 0.3, 3.0 ± 0.0/3.0 ± 0.0, 3.0 ± 0.0/3.0 ± 0.0, and 3.0 ± 0.0/3.0 ± 0.0, respectively, and for 68Ga-PSMA-11 PET/MRI it was 2.6 ± 0.5/2.8 ± 0.4, 3.0 ± 0.2/2.9 ± 0.3, 3.0 ± 0.1/3.0 ± 0.2, 3.0 ± 0.0/3.0 ± 0.0, and 3.0 ± 0.0/3.0 ± 0.0, respectively. CONCLUSION. Our data support routine 3-minute acquisitions, which provided results very similar to those for 4-minute acquisitions. Two-minute acquisitions, although they lowered quality somewhat, provided acceptable performance and warrant consideration. CLINICAL IMPACT. When PC is evaluated using modern PET/MRI equipment, time per bed position may be reduced compared with historically used times. TRIAL REGISTRATION. ClinicalTrials.gov NCT02624518 and NCT02678351.
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Nautiyal A, Jha AK, Mithun S, Sawant V, Jadhav R, Khairnar K, Rangarajan V. Normal Skeletal Standardized Uptake Values Obtained from Quantitative Single-Photon Emission Computed Tomography/Computed Tomography: Time-Dependent Study on Breast Cancer Patients. Indian J Nucl Med 2021; 36:398-411. [PMID: 35125758 PMCID: PMC8771070 DOI: 10.4103/ijnm.ijnm_47_21] [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: 04/08/2021] [Revised: 08/14/2021] [Accepted: 08/31/2021] [Indexed: 11/09/2022] Open
Abstract
Aim: To estimate the standard uptake values (SUVs) of Tc-99m methylene-diphosphonate (Tc-99m MDP) from normal skeletal sites in breast cancer patients using quantitative single-photon emission computed tomography (SPECT). Materials and Methods: A total of 60 breast cancer patients who underwent Tc-99m MDP SPECT/CT study at different postinjection acquisition times were included in this study. Based on postinjection acquisition time, patients were divided into four study groups (n_15 each), i.e. Ist (2 h), IInd (3 h), IIIrd (4 h), and IVth (5 h). Image quantification (SUVmax and SUVmean) was performed using Q.Metrix software. Delineation of volume of interest was shaped around different bones of the skeletal system. Results: The highest normal SUVmax and SUVmean values were observed in lumber and thoracic vertebra (8.89 ± 2.26 and 2.89 ± 0.58) for Group I and in pelvis and thoracic (9.6 ± 1.32 and 3.04 ± 0.64), (10.93 ± 3.91 and 3.65 ± 0.97), (11.33 ± 2.67 and 3.65 ± 0.22) for Group II, III and IV, respectively. Lowest normal SUVmax and SUVmean values were observed in humerus and ribs (3.22 ± 0.67 and 0.97 ± 0.18), (5.16 ± 1.82 and 1.18 ± 0.16) for Group I, IV, and in humerus (3.17 ± 0.58 and 0.85 ± 0.26), (3.98 ± 1.12 and 1.04 ± 0.28) for Group II and III, respectively. Significant difference (P < 0.05) noted in SUVmax for sternum, cervical, humerus, ribs, and pelvis with respect to time. However, significant difference (P < 0.05) noted in SUVmean for all skeletal sites with respect to time. Conclusions: Our study shows variability in normal SUV values for different skeletal sites in breast cancer patients. Vertebral bodies and pelvis contribute highest SUV values. Time dependency of SUVs emphasizes the usefulness of routinely acquired images at the same time after Tc-99m MDP injection, especially in follow-up studies.
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Affiliation(s)
- Amit Nautiyal
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Ashish Kumar Jha
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Sneha Mithun
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Viraj Sawant
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Raveena Jadhav
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Kranti Khairnar
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Venkatesh Rangarajan
- Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Mumbai, Maharashtra, India
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Abstract
A decade of PET/MRI clinical imaging has passed and many of the pitfalls are similar to those on earlier studies. However, techniques to overcome them have emerged and continue to develop. Although clinically significant lung nodules are demonstrable, smaller nodules may be detected using ultrashort/zero echo-time (TE) lung MRI. Fast reconstruction ultrashort TE sequences have also been used to achieve high-resolution lung MRI even with free-breathing. The introduction and improvement of time-of-flight scanners and increasing the axial length of the PET detector arrays have more than doubled the sensitivity of the PET part of the system. MRI for attenuation correction has provided many potential pitfalls, including misclassification of tissue classes based on MRI information for attenuation correction. Although the use of short echo times have helped to address these pitfalls, one of the most exciting developments has been the use of deep learning algorithms and computational neural networks to rapidly provide soft tissue, fat, bone and air information for the attenuation correction as a supplement to the attenuation correction information from fat-water imaging. Challenges with motion correction, particularly respiratory and cardiac remain but are being addressed with respiratory monitors and using PET data. In order to address truncation artefacts, the system manufacturers have developed methods to extend the MR field-of-view for the purpose of the attenuation and scatter corrections. General pitfalls like stitching of body sections for individual studies, optimum delivery of images for viewing and reporting, and resource implications for the sheer volume of data generated remain Methods to overcome these pitfalls serve as a strong foundation for the future of PET/MRI. Advances in the underlying technology with significant evolution in hard-ware and software and the exiting developments in use of deep learning algorithms and computational neural networks will drive the next decade of PET/MRI imaging.
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Affiliation(s)
- Asim Afaq
- University of Iowa Carver College of Medicine, Iowa City; Institute of Nuclear Medicine, UCL/ UCLH London, UK
| | | | | | - Simon Wan
- Institute of Nuclear Medicine, UCL/ UCLH London, UK
| | - Thomas A Hope
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA
| | - Patrick Veit Haibach
- Toronto Joint Dept. Medical Imaging, University Health Network, Sinai Health System, Women's College University of Toronto, Canada
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Evangelista L, Zattoni F, Cassarino G, Artioli P, Cecchin D, Dal Moro F, Zucchetta P. PET/MRI in prostate cancer: a systematic review and meta-analysis. Eur J Nucl Med Mol Imaging 2020; 48:859-873. [PMID: 32901351 PMCID: PMC8036222 DOI: 10.1007/s00259-020-05025-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/31/2020] [Indexed: 12/16/2022]
Abstract
Aim In recent years, the clinical availability of scanners for integrated positron emission tomography (PET) and magnetic resonance imaging (MRI) has enabled the practical potential of multimodal, combined metabolic-receptor, anatomical, and functional imaging to be explored. The present systematic review and meta-analysis summarize the diagnostic information provided by PET/MRI in patients with prostate cancer (PCa). Materials and methods A literature search was conducted in three different databases. The terms used were “choline” or “prostate-specific membrane antigen - PSMA” AND “prostate cancer” or “prostate” AND “PET/MRI” or “PET MRI” or “PET-MRI” or “positron emission tomography/magnetic resonance imaging.” All relevant records identified were combined, and the full texts were retrieved. Reports were excluded if (1) they did not consider hybrid PET/MRI; or (2) the sample size was < 10 patients; or (3) the raw data were not enough to enable the completion of a 2 × 2 contingency table. Results Fifty articles were eligible for systematic review, and 23 for meta-analysis. The pooled data concerned 2104 patients. Initial disease staging was the main indication for PET/MRI in 24 studies. Radiolabeled PSMA was the tracer most frequently used. In primary tumors, the pooled sensitivity for the patient-based analysis was 94.9%. At restaging, the pooled detection rate was 80.9% and was higher for radiolabeled PSMA than for choline (81.8% and 77.3%, respectively). Conclusions PET/MRI proved highly sensitive in detecting primary PCa, with a high detection rate for recurrent disease, particularly when radiolabeled PSMA was used. Electronic supplementary material The online version of this article (10.1007/s00259-020-05025-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laura Evangelista
- Nuclear Medicine Unit, Department of Medicine, Padova University Hospital, Via Giustiniani 2, Padova, Italy.
| | - Fabio Zattoni
- Urology Unit, Department of Medicine, Udine University Hospital, Udine, Italy
| | - Gianluca Cassarino
- Nuclear Medicine Unit, Department of Medicine, Padova University Hospital, Via Giustiniani 2, Padova, Italy
| | - Paolo Artioli
- Nuclear Medicine Unit, Department of Medicine, Padova University Hospital, Via Giustiniani 2, Padova, Italy
| | - Diego Cecchin
- Nuclear Medicine Unit, Department of Medicine, Padova University Hospital, Via Giustiniani 2, Padova, Italy
| | - Fabrizio Dal Moro
- Urology Unit, Department of Medicine, Udine University Hospital, Udine, Italy.,Urology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy
| | - Pietro Zucchetta
- Nuclear Medicine Unit, Department of Medicine, Padova University Hospital, Via Giustiniani 2, Padova, Italy
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Murthy V, Smith RL, Tao DH, Lawhn-Heath CA, Korenchan DE, Larson PEZ, Flavell RR, Hope TA. 68Ga-PSMA-11 PET/MRI: determining ideal acquisition times to reduce noise and increase image quality. EJNMMI Phys 2020; 7:54. [PMID: 32844310 PMCID: PMC7447708 DOI: 10.1186/s40658-020-00322-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/12/2020] [Indexed: 12/21/2022] Open
Abstract
Background In this study, we investigate the impact of increased PET acquisition time per bed position on lesion detectability, standard uptake value, and image noise in 68Ga-PSMA-11 PET/MRI scans. Methods Scans of twenty patients were analyzed in this study. Patients were injected with 68Ga-PSMA-11 (mean, 5.50 ± 1.49 mCi) and imaged on a 3.0 T time-of-flight PET/MRI. PET images were retrospectively reconstructed using 0.5, 1, 2, 4, 7, and 10 min of PET data. Lesion detectability was evaluated on a 5-point Likert Scale for each lesion in each reconstruction. Quantitative analysis was performed measuring image noise and lesion uptake. Results A total of 55 lesions were identified, and lesion detectability increased from 2.07 ± 1.14 for 0.5 min to 4.93 ± 0.26 for 10 min (p < 0.001), with no significant difference detected between 7 and 10 min of scan time. Average SUVmax decreased from 9.89 ± 6.62 for 0.5 min to 8.64 ± 6.81 for 10 min. Noise decreased from 0.72 ± 0.22 for 0.5 min to 0.31 ± 0.12 for 10 min (p < 0.001) and were nearly equivalent between 7 and 10 min. Pairwise interaction terms between size, SUVmax, and scan time were all found to be significant, although the interaction term between SUVmax and scan time was found to be the most significant. Conclusions Increased acquisition duration improves image quality by increasing detectability and reducing noise. In patients with biochemical recurrence, increased acquisition time up to 7 min improves lesion detection.
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Affiliation(s)
- Vishnu Murthy
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Raven L Smith
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Dora H Tao
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Courtney A Lawhn-Heath
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Dave E Korenchan
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Robert R Flavell
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Thomas A Hope
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA. .,UCSF Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, USA. .,Department of Radiology, San Francisco VA Medical Center, San Francisco, CA, USA.
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10
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Zhang YQ, Hu PC, Wu RZ, Gu YS, Chen SG, Yu HJ, Wang XQ, Song J, Shi HC. The image quality, lesion detectability, and acquisition time of 18F-FDG total-body PET/CT in oncological patients. Eur J Nucl Med Mol Imaging 2020; 47:2507-2515. [DOI: 10.1007/s00259-020-04823-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/08/2020] [Indexed: 01/14/2023]
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11
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Grafe H, Lindemann ME, Ruhlmann V, Oehmigen M, Hirmas N, Umutlu L, Herrmann K, Quick HH. Evaluation of improved attenuation correction in whole-body PET/MR on patients with bone metastasis using various radiotracers. Eur J Nucl Med Mol Imaging 2020; 47:2269-2279. [PMID: 32125487 PMCID: PMC7396397 DOI: 10.1007/s00259-020-04738-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/20/2020] [Indexed: 01/18/2023]
Abstract
Purpose This study evaluates the quantitative effect of improved MR-based attenuation correction (AC), including bone segmentation and the HUGE method for truncation correction in PET/MR whole-body hybrid imaging specifically of oncologic patients with bone metastasis and using various radiotracers. Methods Twenty-three patients that underwent altogether 28 whole-body PET/MR examinations with findings of bone metastasis were included in this study. Different radiotracers (18F-FDG, 68Ga-PSMA, 68Ga-DOTATOC, 124I–MIBG) were injected according to appropriate clinical indications. Each of the 28 whole-body PET datasets was reconstructed three times using AC with (1) standard four-compartment μ-maps (background air, lung, muscle, and soft tissue), (2) five-compartment μ-maps (adding bone), and (3) six-compartment μ-maps (adding bone and HUGE truncation correction). The SUVmax of each detected bone lesion was measured in each reconstruction to evaluate the quantitative impact of improved MR-based AC. Relative difference images between four- and six-compartment μ-maps were calculated. MR-based HUGE truncation correction was compared with the PET-based MLAA truncation correction method in all patients. Results Overall, 69 bone lesions were detected and evaluated. The mean increase in relative difference over all 69 lesions in SUVmax was 5.4 ± 6.4% when comparing the improved six-compartment AC with the standard four-compartment AC. Maximal relative difference of 28.4% was measured in one lesion. Truncation correction with HUGE worked robust and resulted in realistic body contouring in all 28 exams and for all 4 different radiotracers. Truncation correction with MLAA revealed overestimations of arm tissue volume in all PET/MR exams with 18F-FDG radiotracer and failed in all other exams with radiotracers 68Ga-PSMA, 68Ga-DOTATOC, and 124I- MIBG due to limitations in body contour detection. Conclusion Improved MR-based AC, including bone segmentation and HUGE truncation correction in whole-body PET/MR on patients with bone lesions and using various radiotracers, is important to ensure best possible diagnostic image quality and accurate PET quantification. The HUGE method for truncation correction based on MR worked robust and results in realistic body contouring, independent of the radiotracers used.
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Affiliation(s)
- Hong Grafe
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany.
| | - Maike E Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Verena Ruhlmann
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Mark Oehmigen
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Nader Hirmas
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany
| | - Harald H Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45147, Essen, Germany.,Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Zollverein, 45141, Essen, Germany
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12
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Rezaei S, Ghafarian P, Bakhshayesh-Karam M, Uribe CF, Rahmim A, Sarkar S, Ay MR. The impact of iterative reconstruction protocol, signal-to-background ratio and background activity on measurement of PET spatial resolution. Jpn J Radiol 2020; 38:231-239. [PMID: 31894449 DOI: 10.1007/s11604-019-00914-3] [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: 09/25/2019] [Accepted: 12/19/2019] [Indexed: 02/04/2023]
Abstract
OBJECTIVES The present study aims to assess the impact of acquisition time, different iterative reconstruction protocols as well as image context (including contrast levels and background activities) on the measured spatial resolution in PET images. METHODS Discovery 690 PET/CT scanner was used to quantify spatial resolutions in terms of full width half maximum (FWHM) as derived (i) directly from capillary tubes embedded in air and (ii) indirectly from 10 mm-diameter sphere of the NEMA phantom. Different signal-to-background ratios (SBRs), background activity levels and acquisition times were applied. The emission data were reconstructed using iterative reconstruction protocols. Various combinations of iterations and subsets (it × sub) were evaluated. RESULTS For capillary tubes, improved FWHM values were obtained for higher it × sub, with improved performance for PSF algorithms relative to non-PSF algorithms. For the NEMA phantom, by increasing acquisition times from 1 to 5 min, intrinsic FWHM for reconstructions with it × sub 32 (54) was improved by 15.3% (13.2%), 15.1% (13.8%), 14.5% (12.8%) and 13.7% (12.7%) for OSEM, OSEM + PSF, OSEM + TOF and OSEM + PSF + TOF, respectively. Furthermore, for all reconstruction protocols, the FWHM improved with more impact for higher it × sub. CONCLUSION Our results indicate that PET spatial resolution is greatly affected by SBR, background activity and the choice of the reconstruction protocols.
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Affiliation(s)
- Sahar Rezaei
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
| | - Pardis Ghafarian
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, 19569-44413, Tehran, Iran. .,PET/CT and Cyclotron Center, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mehrdad Bakhshayesh-Karam
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, 19569-44413, Tehran, Iran.,PET/CT and Cyclotron Center, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Carlos F Uribe
- Department of Functional Imaging, BC Cancer, Vancouver, BC, Canada
| | - Arman Rahmim
- Departments of Radiology and Physics, University of British Columbia, Vancouver, Canada.,Department of Integrative Oncology, BC Cancer Research Centre, Vancouver, Canada
| | - Saeed Sarkar
- Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Ay
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
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Lindemann ME, Guberina N, Wetter A, Fendler WP, Jakoby B, Quick HH. Improving 68Ga-PSMA PET/MRI of the Prostate with Unrenormalized Absolute Scatter Correction. J Nucl Med 2019; 60:1642-1648. [DOI: 10.2967/jnumed.118.224139] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/18/2019] [Indexed: 12/18/2022] Open
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Prostate-Specific Membrane Antigen-Negative Metastases-A Potential Pitfall in Prostate-Specific Membrane Antigen PET. Clin Nucl Med 2018; 43:e186-e188. [PMID: 29659383 DOI: 10.1097/rlu.0000000000002073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ga-PSMA-11 PET/CT was performed in a 74-year-old man because of biochemical recurrence of prostate cancer following radiation therapy of the prostate gland 24 months earlier. Besides focal nuclide accumulation in the prostate gland suggestive of local recurrence, PET scan revealed no further pathologic uptake. However, CT showed multiple pulmonic nodules suggestive of metastases. Thoracotomy and pathologic examination revealed the nodules to be prostate cancer metastasis. Furthermore, immunohistochemical staining with PSMA antibodies demonstrated a virtual lack of PSMA expression. This case demonstrates the possibility of PSMA-negative metastases of prostate cancer an important pitfall that should be known to physicians interpreting PSMA PET.
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Hofman MS, Hicks RJ, Maurer T, Eiber M. Prostate-specific Membrane Antigen PET: Clinical Utility in Prostate Cancer, Normal Patterns, Pearls, and Pitfalls. Radiographics 2018; 38:200-217. [PMID: 29320333 DOI: 10.1148/rg.2018170108] [Citation(s) in RCA: 254] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein that is overexpressed in prostate cancer. Radiolabeled small molecules that bind with high affinity to its active extracellular center have emerged as a potential new diagnostic standard of reference for prostate cancer, resulting in images with extraordinary tumor-to-background contrast. Currently, gallium 68 (68Ga)-PSMA-11 (or HBED-PSMA) is the most widely used radiotracer for PSMA positron emission tomography (PET)/computed tomography (CT) or PSMA PET/magnetic resonance (MR) imaging. Evolving evidence demonstrates superior sensitivity and specificity of PSMA PET compared to conventional imaging, with frequent identification of subcentimeter prostate cancer lesions. PSMA PET is effective for imaging disease in the prostate, lymph nodes, soft tissue, and bone in a "one-stop-shop" examination. There is emerging evidence for its clinical value in staging of high-risk primary prostate cancer and localization of disease in biochemical recurrence. The high sensitivity provided by PSMA PET, with frequent identification of small-volume disease, is redefining patterns of disease spread compared with those seen at conventional imaging. In metastatic castration-resistant prostate cancer, PSMA PET is frequently used for theranostic selection (eg, lutetium 177-PSMA radionuclide therapy), but its potential use for therapy monitoring is still under debate. However, evidence on its proper use to improve patient-related outcomes, particularly in the setting of early biochemical recurrence and targeted treatment of oligometastatic disease, is still missing. Despite the term prostate specific, PSMA functions as a folate hydrolase and is expressed in a range of normal tissues and in other benign and malignant processes. Knowledge of its physiologic distribution and other causes of uptake is essential to minimize false-positive imaging findings. ©RSNA, 2018.
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Affiliation(s)
- Michael S Hofman
- From the Department of Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia (M.S.H., R.J.H.); Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia (M.S.H., R.J.H.); and Departments of Urology and Nuclear Medicine, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany (T.M., M.E.)
| | - Rodney J Hicks
- From the Department of Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia (M.S.H., R.J.H.); Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia (M.S.H., R.J.H.); and Departments of Urology and Nuclear Medicine, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany (T.M., M.E.)
| | - Tobias Maurer
- From the Department of Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia (M.S.H., R.J.H.); Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia (M.S.H., R.J.H.); and Departments of Urology and Nuclear Medicine, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany (T.M., M.E.)
| | - Matthias Eiber
- From the Department of Molecular Imaging, Centre for Cancer Imaging, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia (M.S.H., R.J.H.); Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia (M.S.H., R.J.H.); and Departments of Urology and Nuclear Medicine, Technical University of Munich, Klinikum Rechts der Isar, Munich, Germany (T.M., M.E.)
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Clinical Evaluation of 68Ga-PSMA-II and 68Ga-RM2 PET Images Reconstructed With an Improved Scatter Correction Algorithm. AJR Am J Roentgenol 2018; 211:655-660. [PMID: 29873506 DOI: 10.2214/ajr.17.19356] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Gallium-68-labeled radiopharmaceuticals pose a challenge for scatter estimation because their targeted nature can produce high contrast in these regions of the kidneys and bladder. Even small errors in the scatter estimate can result in washout artifacts. Administration of diuretics can reduce these artifacts, but they may result in adverse events. Here, we investigated the ability of algorithmic modifications to mitigate washout artifacts and eliminate the need for diuretics or other interventions. MATERIALS AND METHODS The model-based scatter algorithm was modified to account for PET/MRI scanner geometry and challenges of non-FDG tracers. Fifty-three clinical 68Ga-RM2 and 68Ga-PSMA-11 whole-body images were reconstructed using the baseline scatter algorithm. For comparison, reconstruction was also processed with modified sampling in the single-scatter estimation and with an offset in the scatter tail-scaling process. None of the patients received furosemide to attempt to decrease the accumulation of radiopharmaceuticals in the bladder. The images were scored independently by three blinded reviewers using the 5-point Likert scale. RESULTS The scatter algorithm improvements significantly decreased or completely eliminated the washout artifacts. When comparing the baseline and most improved algorithm, the image quality increased and image artifacts were reduced for both 68Ga-RM2 and for 68Ga-PSMA-11 in the kidneys and bladder regions. CONCLUSION Image reconstruction with the improved scatter correction algorithm mitigated washout artifacts and recovered diagnostic image quality in 68Ga PET, indicating that the use of diuretics may be avoided.
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17
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Virgolini I, Decristoforo C, Haug A, Fanti S, Uprimny C. Current status of theranostics in prostate cancer. Eur J Nucl Med Mol Imaging 2018; 45:471-495. [PMID: 29282518 PMCID: PMC5787224 DOI: 10.1007/s00259-017-3882-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/07/2017] [Indexed: 12/25/2022]
Abstract
The aim of this review is to report on the current status of prostate-specific membrane antigen (PSMA)-directed theranostics in prostate cancer (PC) patients. The value of 68Ga-PSMA-directed PET imaging as a diagnostic procedure for primary and recurrent PC as well as the role of evolving PSMA radioligand therapy (PRLT) in castration-resistant (CR)PC is assessed. The most eminent data from mostly retrospective studies currently available on theranostics of prostate cancer are discussed. The current knowledge on 68Ga-PSMA PET/CT implicates that primary staging with PET/CT is meaningful in patients with high-risk PC and that the combination with pelvic multi parametric (mp)MR (or PET/mpMR) reaches the highest impact on patient management. There may be a place for 68Ga-PSMA PET/CT in intermediate-risk PC patients as well, however, only a few data are available at the moment. In secondary staging for local recurrence, 68Ga-PSMA PET/mpMR is superior to PET/CT, whereas for distant recurrence, PET/CT has equivalent results and is faster and cheaper compared to PET/mpMR. 68Ga-PSMA PET/CT is superior to 18F / 11Choline PET/CT in primary staging as well as in secondary staging. In patients with biochemical relapse, PET/CT positivity is directly associated with prostate-specific antigen (PSA) increase and amounts to roughly 50% when PSA is raised to ≤0.5 ng/ml and to ≥90% above 1 ng/ml. Significant clinical results have so far been achieved with the subsequent use of radiolabeled PSMA ligands in the treatment of CRPC. Accumulated activities of 30 to 50 GBq of 177Lu-PSMA ligands seem to be clinically safe with biochemical response and PERCIST/RECIST response in around 75% of patients along with xerostomia in 5-10% of patients as the only notable side effect. On the basis of the current literature, we conclude that PSMA-directed theranostics do have a major clinical impact in diagnosis and therapy of PC patients. We recommend that 68Ga-PSMA PET/CT should be performed in primary staging together with pelvic mpMR in high-risk patients and in all patients for secondary staging, and that PSMA-directed therapy is a potent strategy in CRPC patients when other treatment options have failed. The combination of PSMA-directed therapy with existing therapy modalities (such as 223Ra-chloride or androgen deprivation therapy) has to be explored, and prospective clinical multicenter trials with theranostics are warranted.
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Affiliation(s)
- Irene Virgolini
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstraße 35, 6020, Innsbruck, Austria.
| | - Clemens Decristoforo
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstraße 35, 6020, Innsbruck, Austria
| | - Alexander Haug
- Department of Radiology and Nuclear Medicine, Medical University of Vienna, 18-20 Währinger Gürtel, 1090, Vienna, Austria
| | - Stefano Fanti
- Nuclear Medicine Unit, University of Bologna, S. Orsola Hospital Bologna, Massarenti 9, 40138, Bologna, Italy
| | - Christian Uprimny
- Department of Nuclear Medicine, Medical University of Innsbruck, Anichstraße 35, 6020, Innsbruck, Austria
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18
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Lawhn-Heath C, Flavell RR, Korenchan DE, Deller T, Lake S, Carroll PR, Hope TA. Scatter Artifact with Ga-68-PSMA-11 PET: Severity Reduced With Furosemide Diuresis and Improved Scatter Correction. Mol Imaging 2018; 17:1536012118811741. [PMID: 31749411 PMCID: PMC6287320 DOI: 10.1177/1536012118811741] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To assess the utility of furosemide diuresis and the role of an improved scatter correction algorithm in reducing scatter artifact severity on Ga-68- Prostate-specific membrane antigen (PSMA)-11 positron emission tomography (PET). MATERIALS AND METHODS A total of 139 patients underwent Ga-68-PSMA-11 PET imaging for prostate cancer: 47 non-time-of-flight (non-TOF) PET/computed tomography, 51 PET/magnetic resonance imaging (MRI) using the standard TOF scatter correction algorithm, and 41 PET/MRI using an improved TOF scatter correction algorithm. Whole-body PET acquisitions were subdivided into 3 regions: around kidneys; between kidneys and bladder; and around bladder. The images were reviewed, and scatter artifact severity was rated using a Likert-type scale. RESULTS The worst scatter occurred when using non-TOF scatter correction without furosemide, where 42.1% of patients demonstrated severe scatter artifacts in 1 or more regions. Improved TOF scatter correction resulted in the smallest percentage of studies with severe scatter (6.5%). Scatter ratings by region were lowest using improved TOF scatter correction. Furosemide reduced mean scatter severity when using non-TOF and standard TOF. CONCLUSIONS Both furosemide and scatter correction algorithm play a role in reducing scatter in PSMA PET. Improved TOF scatter correction resulted in the lowest scatter severity.
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Affiliation(s)
- Courtney Lawhn-Heath
- Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, CA, USA
| | - Robert R. Flavell
- Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, CA, USA
| | - David E. Korenchan
- Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, CA, USA
| | | | - Spencer Lake
- Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, CA, USA
| | - Peter R. Carroll
- Department of Urology, University of California–San Francisco, San Francisco, CA, USA
| | - Thomas A. Hope
- Department of Radiology and Biomedical Imaging, University of California–San Francisco, San Francisco, CA, USA
- Department of Radiology, San Francisco VA Medical Center, San Francisco, CA, USA
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Domachevsky L, Bernstine H, Goldberg N, Nidam M, Stern D, Sosna J, Groshar D. Early 68GA-PSMA PET/MRI acquisition: assessment of lesion detectability and PET metrics in patients with prostate cancer undergoing same-day late PET/CT. Clin Radiol 2017; 72:944-950. [DOI: 10.1016/j.crad.2017.06.116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/07/2017] [Accepted: 06/12/2017] [Indexed: 11/28/2022]
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Clinical performance of 68Ga-PSMA-11 PET/MRI for the detection of recurrent prostate cancer following radical prostatectomy. Eur J Nucl Med Mol Imaging 2017; 45:20-30. [PMID: 29032394 DOI: 10.1007/s00259-017-3850-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/04/2017] [Indexed: 01/14/2023]
Abstract
PURPOSE Sensitive visualization of recurrent prostate cancer foci is a challenge in patients with early biochemical recurrence (EBR). The recently established 68Ga-PSMA-11 PET/CT has significantly improved the detection rate with published values of up to 55% for patients with a serum PSA concentration between 0.2-0.5 ng/mL. The increased soft tissue contrast in the pelvis using simultaneous 68Ga-PSMA-11 PET/MRI might further improve the detection rate in patients with EBR and low PSA values over PET/CT. METHODS We retrospectively analyzed a cohort of 56 consecutive patients who underwent a 68Ga-PSMA-11 PET/MRI for biochemical recurrence in our institution between April and December 2016 with three readers. Median PSA level was 0.99 ng/mL (interquartile range: 3.1 ng/mL). Detection of PSMA-positive lesions within the prostate fossa, local and distant lymph nodes, bones, or visceral organs was recorded. Agreement among observers was evaluated with Fleiss's kappa (k). RESULTS Overall, in 44 of 56 patients (78.6%) PSMA-positive lesions were detected. In four of nine patients (44.4%) with a PSA < 0.2 ng/mL, suspicious lesions were detected (two pelvic and one paraaortic lymph nodes, and two bone metastases). In eight of 11 patients (72.7%) with a PSA between 0.2 and < 0.5 ng/mL, suspicious lesions were detected (two local recurrences, six lymph nodes, and one bone metastasis). Five out of 20 patients with a PSA < 0.5 ng/mL had extrapelvic disease. In 12 of 15 patients (80.0%) with a PSA between 0.5 and < 2.0 ng/mL, suspicious lesions were detected (four local recurrences, nine lymph nodes, and four bone metastases). In 20 of 21 patients (95.2%) with a PSA >2.0 ng/mL, suspicious lesions were detected. The overall interreader agreement for cancer detection was excellent (κ = 0.796, CI 0.645-0.947). CONCLUSIONS Our data show that 68Ga-PSMA-11 PET/MRI has a high detection rate for recurrent prostate cancer even at very low PSA levels <0.5 ng/mL. Furthermore, even at those low levels extrapelvic disease can be localized in 25% of the cases and local recurrence alone is seen only in 10%.
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Heußer T, Mann P, Rank CM, Schäfer M, Dimitrakopoulou-Strauss A, Schlemmer HP, Hadaschik BA, Kopka K, Bachert P, Kachelrieß M, Freitag MT. Investigation of the halo-artifact in 68Ga-PSMA-11-PET/MRI. PLoS One 2017; 12:e0183329. [PMID: 28817656 PMCID: PMC5560715 DOI: 10.1371/journal.pone.0183329] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 08/02/2017] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVES Combined positron emission tomography (PET) and magnetic resonance imaging (MRI) targeting the prostate-specific membrane antigen (PSMA) with a 68Ga-labelled PSMA-analog (68Ga-PSMA-11) is discussed as a promising diagnostic method for patients with suspicion or history of prostate cancer. One potential drawback of this method are severe photopenic (halo-) artifacts surrounding the bladder and the kidneys in the scatter-corrected PET images, which have been reported to occur frequently in clinical practice. The goal of this work was to investigate the occurrence and impact of these artifacts and, secondly, to evaluate variants of the standard scatter correction method with regard to halo-artifact suppression. METHODS Experiments using a dedicated pelvis phantom were conducted to investigate whether the halo-artifact is modality-, tracer-, and/or concentration-dependent. Furthermore, 31 patients with history of prostate cancer were selected from an ongoing 68Ga-PSMA-11-PET/MRI study. For each patient, PET raw data were reconstructed employing six different variants of PET scatter correction: absolute scatter scaling, relative scatter scaling, and relative scatter scaling combined with prompt gamma correction, each of which was combined with a maximum scatter fraction (MaxSF) of MaxSF = 75% or MaxSF = 40%. Evaluation of the reconstructed images with regard to halo-artifact suppression was performed both quantitatively using statistical analysis and qualitatively by two independent readers. RESULTS The phantom experiments did not reveal any modality-dependency (PET/MRI vs. PET/CT) or tracer-dependency (68Ga vs. 18F-FDG). Patient- and phantom-based data indicated that halo-artifacts derive from high organ-to-background activity ratios (OBR) between bladder/kidneys and surrounding soft tissue, with a positive correlation between OBR and halo size. Comparing different variants of scatter correction, reducing the maximum scatter fraction from the default value MaxSF = 75% to MaxSF = 40% was found to efficiently suppress halo-artifacts in both phantom and patient data. In 1 of 31 patients, reducing the maximum scatter fraction provided new PET-based information changing the patient's diagnosis. CONCLUSION Halo-artifacts are particularly observed for 68Ga-PSMA-11-PET/MRI due to 1) the biodistribution of the PSMA-11-tracer resulting in large OBRs for bladder and kidneys and 2) inaccurate scatter correction methods currently used in clinical routine, which tend to overestimate the scatter contribution. If not compensated for, 68Ga-PSMA-11 uptake pathologies may be masked by halo-artifacts leading to false-negative diagnoses. Reducing the maximum scatter fraction was found to efficiently suppress halo-artifacts.
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Affiliation(s)
- Thorsten Heußer
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Philipp Mann
- Applied Medical Radiation Physics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Christopher M. Rank
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin Schäfer
- Divison of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | | | | | - Klaus Kopka
- Divison of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marc Kachelrieß
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martin T. Freitag
- Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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22
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[Prostate gland - what would urologists like to know from radiologists?]. Radiologe 2017; 57:608-614. [PMID: 28660295 DOI: 10.1007/s00117-017-0273-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
A more than 100-year period, where the prostate was only seen and treated as a whole is coming to an end right now. Finally, high resolution imaging is providing deep insights and detailed information so that new therapeutic procedures can aim for the smallest targets within the gland. The long-standing wish of patients for individual noninvasive diagnostics and treatment of prostate diseases can now be fulfilled by providing new tailored concepts; however, in order to transfer the enormous amount of new information into the specific clinical patient situation, a closely knit interdisciplinary approach is required. In this setting, the traditional outpatient consultation service is overstretched in every aspect. It is now the time for new innovative constructs. The current one-sided service concept for urologists, radiologists and radiation therapists is therefore behind the times and the development of a "prostate management team" with equally cooperating partners from each specialty is the task for the future.
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The accuracy of 68Ga-PSMA PET/CT in primary lymph node staging in high-risk prostate cancer. Eur J Nucl Med Mol Imaging 2017. [DOI: 10.1007/s00259-017-3752-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Uprimny C, Kroiss AS, Fritz J, Decristoforo C, Kendler D, von Guggenberg E, Nilica B, Maffey-Steffan J, di Santo G, Bektic J, Horninger W, Virgolini IJ. Early PET imaging with [68]Ga-PSMA-11 increases the detection rate of local recurrence in prostate cancer patients with biochemical recurrence. Eur J Nucl Med Mol Imaging 2017; 44:1647-1655. [DOI: 10.1007/s00259-017-3743-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 05/24/2017] [Indexed: 11/27/2022]
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