1
|
Preclinical comparison of [ 177Lu]Lu-rhPSMA-10.1 and [ 177Lu]Lu-rhPSMA-10.2 for endoradiotherapy of prostate cancer: biodistribution and dosimetry studies. EJNMMI Radiopharm Chem 2024; 9:18. [PMID: 38407630 PMCID: PMC10897098 DOI: 10.1186/s41181-024-00246-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024] Open
Abstract
BACKGROUND Radiohybrid PSMA-targeted ligands (rhPSMA) have been introduced as a novel platform for theranostic applications. Among a variety of rhPSMA-ligands developed for radioligand therapy, two stereoisomers [177Lu]Lu-rhPSMA-10.1 and -10.2 have been synthesized and initially characterized in preclinical experiments with the aim to provide an optimized binding profile to human serum albumin, a reduction of charge, and thus accelerated kidney excretion, and unaffected or even improved tumor uptake. As both isomers showed similar in vitro characteristics and tumor uptake at 24 h post injection in tumor bearing mice and in order to identify the isomer with the most favorable pharmacokinetics for radioligand therapy, we carried out in-depth biodistribution and dosimetry studies in tumor-bearing and healthy mice. RESULTS rhPSMA-10.1 and -10.2 were radiolabeled with lutetium-177 according to the established procedures of other DOTA-based PSMA ligands and displayed a high and comparable stability in all buffers and human serum (> 97%, 24 h). Biodistribution studies revealed fast clearance from the blood pool (0.3-0.6%ID/g at 1 h) and other background tissues within 48 h. Distinctive differences were found in the kidneys, where [177Lu]Lu-rhPSMA-10.1 displayed lower initial uptake and faster excretion kinetics compared to [177Lu]Lu-rhPSMA-10.2 expressed by a 1.5-fold and ninefold lower uptake value at 1 h and 24 h in healthy animals, respectively. Tumor uptake was comparable and in the range of 8.6-11.6%ID/g for both isomers over 24 h and was maintained up to 168 h at a level of 2.2 ± 0.8 and 4.1 ± 1.4%ID/g for [177Lu]Lu-rhPSMA-10.1 and [177Lu]Lu-rhPSMA-10.2, respectively. CONCLUSION Our preclinical data on biodistribution and dosimetry indicate a more favorable profile of [177Lu]Lu-rhPSMA-10.1 compared to [177Lu]Lu-rhPSMA-10.2 for PSMA-targeted radioligand therapy. [177Lu]Lu-rhPSMA-10.1 shows fast kidney clearance kinetics resulting in excellent tumor-to-organ ratios over a therapy relevant time course. Meanwhile, [177Lu]Lu-rhPSMA-10.1 is currently being investigated in clinical phase I/II studies in patients with mCRPC (NCT05413850), in patients with high-risk localized PC (NCT06066437, Nautilus Trial) and after external beam radiotherapy (NCT06105918).
Collapse
|
2
|
Validating a minipig model of reversible cerebral demyelination using human diagnostic modalities and electron microscopy. EBioMedicine 2024; 100:104982. [PMID: 38306899 PMCID: PMC10850420 DOI: 10.1016/j.ebiom.2024.104982] [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: 12/10/2022] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND Inflammatory demyelinating diseases of the central nervous system, such as multiple sclerosis, are significant sources of morbidity in young adults despite therapeutic advances. Current murine models of remyelination have limited applicability due to the low white matter content of their brains, which restricts the spatial resolution of diagnostic imaging. Large animal models might be more suitable but pose significant technological, ethical and logistical challenges. METHODS We induced targeted cerebral demyelinating lesions by serially repeated injections of lysophosphatidylcholine in the minipig brain. Lesions were amenable to follow-up using the same clinical imaging modalities (3T magnetic resonance imaging, 11C-PIB positron emission tomography) and standard histopathology protocols as for human diagnostics (myelin, glia and neuronal cell markers), as well as electron microscopy (EM), to compare against biopsy data from two patients. FINDINGS We demonstrate controlled, clinically unapparent, reversible and multimodally trackable brain white matter demyelination in a large animal model. De-/remyelination dynamics were slower than reported for rodent models and paralleled by a degree of secondary axonal pathology. Regression modelling of ultrastructural parameters (g-ratio, axon thickness) predicted EM features of cerebral de- and remyelination in human data. INTERPRETATION We validated our minipig model of demyelinating brain diseases by employing human diagnostic tools and comparing it with biopsy data from patients with cerebral demyelination. FUNDING This work was supported by the DFG under Germany's Excellence Strategy within the framework of the Munich Cluster for Systems Neurology (EXC 2145 SyNergy, ID 390857198) and TRR 274/1 2020, 408885537 (projects B03 and Z01).
Collapse
|
3
|
EFOMP policy statement NO. 19: Dosimetry in nuclear medicine therapy - Molecular radiotherapy. Phys Med 2023; 116:103166. [PMID: 37926641 DOI: 10.1016/j.ejmp.2023.103166] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 10/22/2023] [Indexed: 11/07/2023] Open
Abstract
The European Council Directive 2013/59/Euratom (BSS Directive) includes optimisation of treatment with radiotherapeutic procedures based on patient dosimetry and verification of the absorbed doses delivered. The present policy statement summarises aspects of three directives relating to the therapeutic use of radiopharmaceuticals and medical devices, and outlines the steps needed for implementation of patient dosimetry for radioactive drugs. To support the transition from administrations of fixed activities to personalised treatments based on patient-specific dosimetry, EFOMP presents a number of recommendations including: increased networking between centres and disciplines to support data collection and development of codes-of-practice; resourcing to support an infrastructure that permits routine patient dosimetry; research funding to support investigation into individualised treatments; inter-disciplinary training and education programmes; and support for investigator led clinical trials. Close collaborations between the medical physicist and responsible practitioner are encouraged to develop a similar pathway as is routine for external beam radiotherapy and brachytherapy. EFOMP's policy is to promote the roles and responsibilities of medical physics throughout Europe in the development of molecular radiotherapy to ensure patient benefit. As the BSS directive is adopted throughout Europe, unprecedented opportunities arise to develop informed treatments that will mitigate the risks of under- or over-treatments.
Collapse
|
4
|
The Impact of PSMA PET-Based Eligibility Criteria Used in the Prospective Phase II TheraP Trial in Metastatic Castration-Resistant Prostate Cancer Patients Undergoing Prostate-Specific Membrane Antigen-Targeted Radioligand Therapy. J Nucl Med 2023:jnumed.122.265346. [PMID: 37290796 DOI: 10.2967/jnumed.122.265346] [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: 12/19/2022] [Revised: 03/24/2023] [Indexed: 06/10/2023] Open
Abstract
Prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) has shown encouraging results for treatment of metastatic castration-resistant prostate cancer (mCRPC) in the prospective, multicenter, randomized phase II TheraP study. The inclusion criteria for that study comprised a pretherapeutic 68Ga-PSMA-11 PET scan showing sufficient tumor uptake using a predefined threshold and the absence of 18F-FDG-positive, PSMA ligand-negative tumor lesions. However, the prognostic value of these PET-based inclusion criteria remains unclear. Therefore, we evaluated the outcome of mCRPC patients treated with PSMA RLT using TheraP as well as other TheraP-based PET inclusion criteria. Methods: First, patients were dichotomized into 2 groups whose PSMA PET scans did (TheraP contrast-enhanced PSMA [cePSMA] PET-positive) or did not (TheraP cePSMA PET-negative) fulfill the inclusion criteria of TheraP. Notably, unlike in TheraP, 18F-FDG PET was not performed on our patients. Prostate-specific antigen (PSA) response (PSA decline ≥ 50% from baseline), PSA progression-free survival, and overall survival (OS) were compared. Additionally, patients were further dichotomized according to predefined SUVmax thresholds different from those used in TheraP to analyze their potential impact on outcome as well. Results: In total, 107 mCRPC patients were included in this analysis (TheraP cePSMA PET-positive, n = 77; TheraP cePSMA PET-negative, n = 30). PSA response rates were higher in TheraP cePSMA PET-positive patients than in TheraP cePSMA PET-negative patients (54.5% vs. 20%, respectively; P = 0.0012). The median PSA progression-free survival (P = 0.007) and OS (P = 0.0007) of patients were significantly longer in the TheraP cePSMA PET-positive group than in the TheraP cePSMA PET-negative group. Moreover, being in the TheraP cePSMA PET-positive group was identified as a significant prognosticator of longer OS (P = 0.003). The application of different SUVmax thresholds for a single hottest lesion demonstrated no influence on outcome in patients eligible for PSMA RLT. Conclusion: Patient selection for PSMA RLT according to the inclusion criteria of TheraP led to a better treatment response and outcome in our preselected patient cohort. However, a relevant number of patients not fulfilling these criteria also showed substantial rates of response.
Collapse
|
5
|
Performance evaluation of a novel multi-pinhole collimator on triple-NaI-detector SPECT/CT for dedicated myocardial imaging. EJNMMI Phys 2023; 10:24. [PMID: 36964406 PMCID: PMC10039219 DOI: 10.1186/s40658-023-00541-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 03/01/2023] [Indexed: 03/26/2023] Open
Abstract
BACKGROUND In this study we evaluated the imaging capabilities of a novel Multi-pinhole collimator (MPH-Cardiac) specially designed for nuclear cardiology imaging on a Triple-NaI-detector based SPECT/CT system. METHODS 99mTc point source measurements covering the field of view (FOV) were used to determine tomographic sensitivity (TSpointsource) and spatial resolution. Organ-size tomographic sensitivity (TSorgan) was measured with a left ventricle (LV) phantom filled with typical myocardial activity of a patient scan. Reconstructed image uniformity was measured with a 140 mm diameter uniform cylinder phantom. Using the LV phantom once filled with 99mTc and after with 123I, Contrast-to-noise ratio (CNR) was measured on the reconstructed images by ROI analysis on the myocardium activity and on the LV cavity. Furthermore, a polar map analysis was performed determining Spill-Over-Ratio in water (SORwater) and image noise. The results were compared with that of a dual-head parallel-hole low energy high resolution (LEHR) collimator system. A patient with suspected coronary artery disease (CAD) was scanned on the LEHR system using local protocol of 16 min total acquisition time, followed by a 4-min MPH-Cardiac scan. RESULTS Peak TSpointsource was found to be 1013 cps/MBq in the axial center of the FOV while it was decreasing toward the radial edges. TSorgan in the CFOV was found to be 134 cps/MBq and 700 cps/MBq for the LEHR and MPH-Cardiac, respectively. Average spatial resolution throughout the FOV was 4.38 mm FWHM for the MPH-Cardiac collimator. Reconstructed image uniformity values were found to be 0.292% versus 0.214% for the LEHR and MPH-Cardiac measurements, respectively. CNR was found to be higher in case of MPH-Cardiac than for LEHR in case of 99mTc (15.5 vs. 11.7) as well as for 123I (13.5 vs. 8.3). SORwater values were found to be 28.83% and 21.1% for the 99mTc measurements, and 31.44% and 24.33% for the 123I measurements for LEHR and MPH-Cardiac, respectively. Pixel noise of the 99mTc polar maps resulted in values of 0.38% and 0.24% and of the 123I polar maps 0.62% and 0.21% for LEHR and MPH-Cardiac, respectively. Visually interpreting the patient scan images, MPH-Cardiac resulted in better image contrast compared to the LEHR technique with four times shorter scan duration. CONCLUSIONS The significant image quality improvement achieved with dedicated MPH-Cardiac collimator on triple head SPECT/CT system paves the way for short acquisition and low-dose cardiovascular SPECT applications.
Collapse
|
6
|
PET scatter estimation using deep learning U-Net architecture. Phys Med Biol 2023; 68. [PMID: 36240745 DOI: 10.1088/1361-6560/ac9a97] [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: 06/13/2022] [Accepted: 10/13/2022] [Indexed: 03/11/2023]
Abstract
Objective.Positron emission tomography (PET) image reconstruction needs to be corrected for scatter in order to produce quantitatively accurate images. Scatter correction is traditionally achieved by incorporating an estimated scatter sinogram into the forward model during image reconstruction. Existing scatter estimated methods compromise between accuracy and computing time. Nowadays scatter estimation is routinely performed using single scatter simulation (SSS), which does not accurately model multiple scatter and scatter from outside the field-of-view, leading to reduced qualitative and quantitative PET reconstructed image accuracy. On the other side, Monte-Carlo (MC) methods provide a high precision, but are computationally expensive and time-consuming, even with recent progress in MC acceleration.Approach.In this work we explore the potential of deep learning (DL) for accurate scatter correction in PET imaging, accounting for all scatter coincidences. We propose a network based on a U-Net convolutional neural network architecture with 5 convolutional layers. The network takes as input the emission and computed tomography (CT)-derived attenuation factor (AF) sinograms and returns the estimated scatter sinogram. The network training was performed using MC simulated PET datasets. Multiple anthropomorphic extended cardiac-torso phantoms of two different regions (lung and pelvis) were created, considering three different body sizes and different levels of statistics. In addition, two patient datasets were used to assess the performance of the method in clinical practice.Main results.Our experiments showed that the accuracy of our method, namely DL-based scatter estimation (DLSE), was independent of the anatomical region (lungs or pelvis). They also showed that the DLSE-corrected images were similar to that reconstructed from scatter-free data and more accurate than SSS-corrected images.Significance.The proposed method is able to estimate scatter sinograms from emission and attenuation data. It has shown a better accuracy than the SSS, while being faster than MC scatter estimation methods.
Collapse
|
7
|
The Maximum Standardized Uptake Value in Patients with Recurrent or Persistent Prostate Cancer after Radical Prostatectomy and PSMA-PET-Guided Salvage Radiotherapy – A Multicenter Retrospective Analysis. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.1225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
8
|
The discrepancy between FDG uptake and myocardial fibrosis in patients with pulmonary arterial hypertension – PET/MRI study. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Inflammatory processes play an important role in pulmonary arterial hypertension (PAH) pathophysiology. We previously confirmed that in case of right ventricle (RV) failure, changes of cytokines' levels are correlated with myocardial metabolic and hemodynamic alterations observed in PET/MRI hybrid imaging. Presence of late gadolinium enhancement (LGE) in RV insertion points (RVIPs) has been found in majority of PAH patients and is often recognized as evidence of myocardial fibrosis due to RV pressure overload. As qualitative and/or quantitative assessments of LGE may vary due to natural PAH progression or specific therapy, we hypothesized that simple presence of LGE at RVIPs is not unequivocal to fibrotic tissue (without metabolic activity).
Purpose
To check the relationship between LGE mass and 18F-fluorodexyglucose uptake in RV insertion points in PAH patients using PET/MRI hybrid imaging.
Methods
Twenty-eight clinically stable PAH patients (49.9±15.9 years) had simultaneous PET/MRI scans during baseline and follow up (FU) visits, Figure. 18F-fluorodexyglucose (FDG) was used as a tracer and its cardiac uptake was presented as a maximum standardized uptake value (SUV) for RV insertion points (SUV in RVIPS). Septal delayed enhancement mass was quantified in RVIPs and presented as LGE mass. Occurrences of clinical end-points (CEP, defined as death or clinical deterioration) were assessed during 24 months observation.
Results
LGE was found in RVIPs of all PAH patients. Mean LGE mass was 6.32±4.41 g and mean SUV in RVIPS was 7.28±5.36. Follow up values were 8.01±7.75g (p=0.4) and 5.80±3.16 (p=0.16), respectively. We observed significant correlation between baseline SUV in RVIPS and mean pulmonary pressure, mPAP (r=0.49, p=0.04) but no correlation was found between LGE mass and SUV in RVIPS (in both baseline and FU scans).
Between baseline and follow up visits, 16 patients had CEP and needed PAH therapy escalation. CEP+ group of PAH patients presented higher baseline LGE mass (7.53±4.75 vs 3.92±2.21, p=0.04) and SUV in RVIPS (7.27±5.42 vs 6.01±4.52, p=0.4). In all CEP patients who initiated prostacycline therapy and survived (n=8, 50%), SUV in RVIPS decreased in FU PET scans together with an increase in LGE mass in MRI. At FU visits we also observed significant improvement of MRI-derived RV ejection fraction (45.1±9.6% to 52.4±12.9%, p=0.01), and mPAP (50.5±18.3 to 42.8±18.6 mmHg, p=0.03).
Conclusions
Effective PAH therapy have an impact on both LGE mass and FDG uptake in cardiac local tissue changes. Since there was no correlation between LGE mass and FDG uptake RV insertion points, the question arises what the cause of these LGE changes is. Increased fibrosis should cause diminished local glucose metabolism. This phenomenon opens new questions concerning pathophysiology processes in RVIPs and requires confirmation on bigger PAH population.
Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Center for Science in Poland
Collapse
|
9
|
Platelet sTWEAK and plasma IL-6 are associated with 18F-fluorodeoxyglucose uptake in right ventricles of patients with pulmonary arterial hypertension: A pilot study. ADV CLIN EXP MED 2022; 31:991-998. [PMID: 35467090 DOI: 10.17219/acem/149198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Cytokines soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) and interleukin 6 (IL-6) are involved in immune response, proliferation, apoptosis, and cardiovascular pathologies. We have previously confirmed that changes of their platelet or plasma contents are associated with pulmonary arterial hypertension (PAH). The positron emission tomography/magnetic resonance imaging (PET/MRI) hybrid imaging provides detailed insight into right ventricle (RV) hemodynamic and metabolic function. OBJECTIVES To evaluate the relationship between RV parameters obtained using PET/MRI and concentrations of plasma and platelet sTWEAK and IL-6 in stable PAH patients. MATERIAL AND METHODS Eighteen stable PAH patients (48.44 ±16.7 years) had simultaneous PET/MRI scans with 18F-fluorodeoxyglucose (18F-FDG) performed. Its uptake was presented as a standardized uptake value (SUV) for RV and left ventricle (LV). Cytokines concentrations were measured in platelet-poor plasma and platelet lysate. Follow-up time of this study was 58 months; the combined endpoint (CEP) was defined as death or clinical deterioration. RESULTS We observed significant correlations between platelet sTWEAK levels, plasma IL-6 and PET parameter SUVRV/LV (r = -0.57, p = 0.011; r = 0.50, p = 0.032, respectively). In logistic regression, platelet sTWEAK and IL-6 were both prognostic factors for unfavorable ratio of SUVRV/LV higher than 1 (hazard ratio (HR) = 0.44, 95% confidence interval (95% CI): [0.23; 0.84], p = 0.017; and HR = 3.62, 95% CI: [1.21; 10.17], p = 0.011, respectively). Furthermore, their concentrations were related with prognostically important higher late gadolinium enhancement mass index (LGEMI) and RV global longitudinal strain/systolic pulmonary artery pressure (RV GLS/sPAP) values. Patients who had CEP in follow-up (n = 13) had significantly lower platelet sTWEAK content and higher plasma IL-6 at baseline than stable patients. Lower platelet sTWEAK was related to a worse prognosis in log-rank test (p = 0.006). Platelet sTWEAK and plasma IL-6 together with RV GLS/sPAP, RV ejection fraction (RVEF), mean pulmonary arterial pressure (mPAP), and SUVRV/LV were significantly associated with time to CEP in univariate Cox analysis. CONCLUSIONS The sTWEAK and IL-6 concentrations in PAH patients are linked with metabolic and functional changes of RV visualized in PET/MRI, and both sTWEAK and IL-6 predict clinical deterioration.
Collapse
|
10
|
Preclinical biodistribution and dosimetry and human biodistribution comparing 18F-rhPSMA-7 and single isomer 18F-rhPSMA-7.3. EJNMMI Res 2022; 12:8. [PMID: 35119557 PMCID: PMC8816989 DOI: 10.1186/s13550-021-00872-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 12/06/2021] [Indexed: 12/03/2022] Open
Abstract
Background Radiohybrid prostate-specific membrane antigen (rhPSMA) ligands such as 18F-rhPSMA-7 are a new class of theranostic agents in clinical development for prostate cancer. We compared preclinical dosimetry and human biodistribution of 18F-rhPSMA-7 with that of single diastereoisomer form, 18F-rhPSMA-7.3. Methods Preclinical dosimetry was performed with SCID-mice sacrificed at multiple timepoints (10–300 min) post-injection of 25.6 ± 3.6 MBq 18F-rhPSMA-7 or 28.5 ± 4.8 MBq 18F-rhPSMA-7.3 (n = 3–6 mice per timepoint). Heart, lung, liver, spleen, pancreas, fat, stomach, small intestine, large intestine, kidney, muscle, bone, bladder, testicles, tail, and brain tissue were harvested, and urine and blood samples collected. Percentage of injected dose per gram was calculated. Absorbed doses were estimated with OLINDA/EXM 1.0. 18F-rhPSMA-7 (n = 47) and 18F-rhPSMA-7.3 (n = 33) PET/CT exams were used to estimate human biodistribution. Mean (range) injected activities were 324 (236–424) MBq versus 345 (235–420) MBq, and acquisition times were 84 (42–166) versus 76 (59–122) minutes for 18F-rhPSMA-7 versus 18F-rhPSMA-7.3, respectively. SUVmean was determined for background (gluteal muscle), normal organs (salivary glands, blood pool, lung, liver, spleen, pancreas, duodenum, kidney, bladder, bone) and up to three representative tumour lesions. Qualitative analyses assessed image quality, non-specific blood pool activity, and background uptake in bone/marrow using 3/4-point scales. Results Preclinical dosimetry revealed that at 3.5 h and 1 h bladder voiding intervals, the extrapolated total effective doses were 26.6 and 12.2 µSv/MBq for 18F-rhPSMA-7 and 21.7 and 12.8 µSv/MBq for 18F-rhPSMA-7.3 respectively. Human biodistribution of both agents was typical of other PSMA-ligands and broadly similar to each other; SUVmean were 16.9 versus 16.2 (parotid gland), 19.6 versus 19.9 (submandibular gland), 2.0 versus 1.9 (blood pool, p < 0.005), 0.7 versus 0.7 (lungs), 7.0 versus 7.3 (liver), 9.1 versus 8.4 (spleen), 32.4 versus 35.7 (kidney), 2.5 versus 2.8 (pancreas), 10.9 versus 11.0 (duodenum), 1.1 versus 1.3 (bone) and 4.6 versus 2.0 (bladder; p < 0.001) for 18F-rhPSMA-7 versus 18F-rhPSMA-7.3, respectively. Tumour SUVmean was higher for 18F-rhPSMA-7.3 (32.5 ± 42.7, n = 63 lesions) than for 18F-rhPSMA-7 (20.0 ± 20.2, n = 89 lesions). Conclusions Radiation dosimetry is favourable for both agents. Radiation exposure, assuming a 1 h voiding interval, is less than 5 mSv after injection of 370 MBq. 18F-rhPSMA-7.3 showed significantly lower bladder uptake, and a higher uptake trend in tumours compared with 18F-rhPSMA-7. Supplementary Information The online version contains supplementary material available at 10.1186/s13550-021-00872-w.
Collapse
|
11
|
Integrative analysis of hybrid PET/MR improves recovery prediction of left ventricular contractility after percutaneous revascularisation of coronary chronic total occlusions. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.0262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
The clinical indication to revascularization of coronary chronic total occlusions (CTO) is set on viability assessment through well-established imaging methods. Precise characterization of the myocardium allows a better interventional risk stratification before revascularization. Hybrid positron emission tomography/magnetic resonance (PET/MR) scanners allow the combination of image based biomarkers through simultaneous acquisition and may potentially improve the prediction of therapy response. This study aims to evaluate the accuracy in recovery prediction after CTO revascularization by combining information of myocardial viability and wall motion abnormalities (WMA) from PET/MR exams.
Methods
Viability was assessed with PET/MR imaging in 22 patients before percutaneous revascularization of a CTO. A cardiac MR imaging was performed at follow-up after 6 months. Segmental WMA was assessed on the AHA 17-segments model from cine images at baseline and follow-up with a 5-point scale. Recovery of WMA was predicted using six different models combining parameters from fluorodeoxyglucose (FDG) uptake, transmural extent of the scar with late gadolinium enhancement image (LGE), T1 mapping, and WMA at baseline. From 374 myocardial segments, we considered only 82 that were completely characterized and presented at least hypokinetic WMA at baseline. 46 of them were supplied by the treated CTO artery (CTO-subtended), wherefrom 16 segments recovered the contractility.
A Random Forest classifier was applied for recovery prediction. Training and testing data were selected through stratified random sampling (50 iterations) with replacement from the two sets: CTO-subtended and non-CTO-subtended segments. To compensate for class imbalance and limited sample size, SMOTE oversampling was applied to the training data. Prediction assessment was based on balanced accuracy (bAcc), sensitivity, specificity, ROC AUC, and Precision-Recall AUC (PR AUC), while Wilcoxon test with a Bonferroni's correction was used for comparison between the proposed models and LGE+FDG, which has shown the best performance in previous studies [1,2].
Results
The best model for the prediction of recovery after revascularisation was the combination of LGE+FDG+WMA+T1mapping (bAcc 0.62±0.11, sensitivity 0.72±0.18, specificity 0.70±0.19, ROC AUC 0.67±0.12, PR AUC 0.60±0.12), followed by LGE+FDG+WMA, LGE+FDG+T1mapping, LGE+FDG, LGE, and FDG, respectively. The first model statistically significantly (p-value<0.01) outperformed the reference model LGE+FDG (bAcc 0.54±0.11, sensitivity: 0.67±0.18, specificity 0.55±0.19, ROC AUC 0.56±0.13, PR AUC 0.47±0.10).
Conclusion
This study documents the benefits of a hybrid PET/MR multiparametric assessment beyond the standard analysis based on FDG uptake and LGE for the prediction of contractility recovery after revascularization of CTO of the coronary arteries.
Funding Acknowledgement
Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 764458 PETMR protocolROC AUC comparsion
Collapse
|
12
|
Comparative Preclinical Biodistribution, Dosimetry, and Endoradiotherapy in Metastatic Castration-Resistant Prostate Cancer Using 19F/ 177Lu-rhPSMA-7.3 and 177Lu-PSMA I&T. J Nucl Med 2021; 62:1106-1111. [PMID: 33443072 DOI: 10.2967/jnumed.120.254516] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/04/2020] [Indexed: 12/29/2022] Open
Abstract
Radiohybrid prostate-specific membrane antigen (rhPSMA) ligands are applicable as radiochemical twins for both diagnostic PET imaging and endoradiotherapy. On the basis of preliminary data as a diagnostic ligand, the isomer rhPSMA-7.3 is a promising candidate for potential endoradiotherapy. The aim of this preclinical evaluation was to assess the biodistribution, dosimetry, and therapeutic efficacy of 19F/177Lu-rhPSMA-7.3 in comparison to the established therapeutic agent 177Lu-PSMA I&T (imaging and therapy). Methods: The biodistribution of 19F/177Lu-rhPSMA-7.3 and 177Lu-PSMA I&T was determined in LNCaP tumor-bearing severe combined immunodeficiency (SCID) mice after sacrifice at defined time points up to 7 d (n = 5). Organs and tumors were dissected, percentage injected dose per gram (%ID/g) was determined, and dosimetry was calculated using OLINDA/EXM, version 1.0. The therapeutic efficacy of a single 30-MBq dose of 19F/177Lu-rhPSMA-7.3 (n = 7) was compared with that of 177Lu-PSMA I&T in treatment groups (n = 7) and control groups (n = 6-7) using C4-2 tumor-bearing SCID mice by evaluating tumor growth and survival over 6 wk after treatment. Results: The biodistribution of 19F/177Lu-rhPSMA-7.3 revealed fast blood clearance (0.63 %ID/g at 1 h after injection), and the highest activity uptake was in the spleen and kidneys, particularly in the first hour (33.25 %ID/g and 207.6 %ID/g, respectively, at 1 h after injection), indicating a renal excretion pathway. Compared with 177Lu-PSMA I&T, 19F/177Lu-rhPSMA-7.3 exhibited an initial (1 h) 2.6-fold higher tumor uptake in LNCaP xenografts and a longer retention (4.5 %ID/g vs. 0.9 %ID/g at 168 h). The tumor dose of 19F/177Lu-rhPSMA-7.3 was substantially higher (e.g., 7.47 vs. 1.96 µGy/MBq at 200 mm3) than that of 177Lu-PSMA I&T. In most organs, absorbed doses were higher for 177Lu-PSMA I&T. A significantly greater tumor size reduction was shown for a single dose of 19F/177Lu-rhPSMA-7.3 than for 177Lu-PSMA I&T at the end of the experiment (P = 0.0167). At the predefined termination of the experiment at 6 wk, 7 of 7 and 3 of 7 mice were still alive in the 19F/177Lu-rhPSMA-7.3 and 177Lu-PSMA I&T groups, respectively, compared with the respective control groups, with 0 of 7 and 0 of 6 mice. Conclusion: Compared with 177Lu-PSMA I&T, 19F/177Lu-rhPSMA-7.3 can be considered a suitable candidate for clinical translation because it has similar clearance kinetics and a similar radiation dose to healthy organs but superior tumor uptake and retention. Preliminary treatment experiments showed a favorable antitumor response.
Collapse
|
13
|
5964Hybrid PET/MR imaging for the prediction of left ventricular (LV) recovery after revascularisation of chronic total occluded coronaries. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz746.0105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Background
Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) represents one of the major challenges in interventional cardiology. Physicians are still reluctant in referring for PCI, assuming non viability of the myocardium subtended by the CTO. Data are controversial in assessing the improvement of left ventricular (LV) wall motion after revascularisation and the prognostic value of viability testing to guide patient selection.
Purpose
The aim of this study was to determine, whether hybrid fluorodeoxyglucose positron emission tomography/magnetic resonance (FDG PET/MR) imaging allows a more accurate prediction of LV regional wall motion recovery after successful PCI of CTOs in comparison to PET or MR alone.
Methods
We enrolled 49 consecutive symptomatic patients with CTO and evidence of wall motion abnormality in the corresponding CTO-territory. All patients underwent hybrid FDG PET/MR imaging as semi-quantitative assessment of myocardial viability - glucose metabolism in PET and late gadolinium enhancement (LGE) transmurality in MR – prior of PCI of the CTO. Follow-up MRI was performed in 23 patients 3–6 months after successful revascularisation to evaluate wall motion changes.
Results
We assessed viability in 124 myocardial segments subtended by a CTO in 23 patients with successful PCI who underwent serial imaging. Segments with wall motion abnormality at baseline (n=80) were analysed. Most of these segments (n=54, 68%) were concordantly assessed viable by PET and MR, conversely only 2 (2%) segments were assessed non-viable by both imaging techniques. However, almost one third of the segments showed discordant patterns of viability either PET not viable/ MR viable (3 (4%) segments) or PET viable/ MR not viable (21 (26%) segments): particularly the latter revealed a significant wall motion improvement (p=0.033).
The combination of PET and MR showed a fair accuracy in predicting myocardial segments with wall motion improvement after CTO revascularisation (PET/MR area under ROC curve (AUC) 0.72, SE 0.07, p=0.002), which was superior to MR-LGE (AUC=0.66, SE 0.09) and FDG-PET (AUC=0.58, SE 0.10) alone (Figure).
Comparisons of ROC curves
Conclusion
Hybrid PET/MR imaging prior to successful CTO showed a better performance than PET or MR alone in predicting regional improvement of disturbed wall motion.
The complimentary information derived from both modalities may particularly help to identify small amounts of viable epicardial myocardium within large scars which can improve contractility after CTO-revascularisation.
Collapse
|
14
|
Classification of Polar Maps from Cardiac Perfusion Imaging with Graph-Convolutional Neural Networks. Sci Rep 2019; 9:7569. [PMID: 31110326 PMCID: PMC6527613 DOI: 10.1038/s41598-019-43951-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 02/25/2019] [Indexed: 11/09/2022] Open
Abstract
Myocardial perfusion imaging is a non-invasive imaging technique commonly used for the diagnosis of Coronary Artery Disease and is based on the injection of radiopharmaceutical tracers into the blood stream. The patient's heart is imaged while at rest and under stress in order to determine its capacity to react to the imposed challenge. Assessment of imaging data is commonly performed by visual inspection of polar maps showing the tracer uptake in a compact, two-dimensional representation of the left ventricle. This article presents a method for automatic classification of polar maps based on graph convolutional neural networks. Furthermore, it evaluates how well localization techniques developed for standard convolutional neural networks can be used for the localization of pathological segments with respect to clinically relevant areas. The method is evaluated using 946 labeled datasets and compared quantitatively to three other neural-network-based methods. The proposed model achieves an agreement with the human observer on 89.3% of rest test polar maps and on 91.1% of stress test polar maps. Localization performed on a fine 17-segment division of the polar maps achieves an agreement of 83.1% with the human observer, while localization on a coarse 3-segment division based on the vessel beds of the left ventricle has an agreement of 78.8% with the human observer. Our method could thus assist the decision-making process of physicians when analyzing polar map data obtained from myocardial perfusion images.
Collapse
|
15
|
Galectin-3 Targeting in Thyroid Orthotopic Tumors Opens New Ways to Characterize Thyroid Cancer. J Nucl Med 2018; 60:770-776. [PMID: 30361380 DOI: 10.2967/jnumed.118.219105] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/10/2018] [Indexed: 11/16/2022] Open
Abstract
Preoperative characterization of thyroid nodules is challenging since thyroid scintigraphy fails to distinguish between benign and malignant lesions. Galectin-3 (gal-3) is expressed in well-differentiated and in undifferentiated thyroid cancer types but not in normal thyrocytes and benign thyroid lesions. Herein, we aimed to validate gal-3 targeting as a specific method to detect non-radioiodine-avid thyroid cancer in thyroid orthotopic tumor models. Methods: Papillary (BcPAP) and anaplastic (CAL62 and FRO82-1) thyroid carcinoma cell lines were characterized via Western blot and polymerase chain reaction for gal-3 and sodium-iodide symporter (NIS) expression. An 89Zr-labeled F(ab')2 antigal-3 was generated and characterized for binding versus 125I on 2- and 3-dimensional cell cultures. The thyroid carcinoma cells were inoculated into the left thyroid lobe of athymic nude mice, and the orthotopic tumor growth was monitored via ultrasound and fluorescence molecular tomography. Head-to-head PET/CT comparison of 124I versus 89Zr-deferoxamine (DFO)-F(ab')2 antigal-3 was performed, followed by biodistribution studies and immunohistochemical analysis for gal-3 and NIS expression. Results: The thyroid carcinoma cells investigated were invariably gal-3-positive while presenting low or lost NIS expression. 89Zr-DFO-F(ab')2 antigal-3 tracer showed high affinity to gal-3 (dissociation constant, ∼3.9 nM) and retained immunoreactivity (>75%) on 2-dimensional cell cultures and on tumor spheroids. 125I internalization in FRO82-1, BcPAP, and CAL62 was directly dependent on NIS expression, both in 2-dimensional and tumor spheroids. PET/CT imaging showed 89Zr-DFO-F(ab')2 antigal-3 signal associated with the orthotopically implanted tumors only; no signal was detected in the tumor-free thyroid lobe. Conversely, PET imaging using 124I showed background accumulation in tumor-infiltrated lobe, a condition simulating the presence of non-radioiodine-avid thyroid cancer nodules, and high accumulation in normal thyroid lobe. Imaging data were confirmed by tracer biodistribution studies and immunohistochemistry. Conclusion: A specific and selective visualization of thyroid tumor by targeting gal-3 was demonstrated in the absence of radioiodine uptake. Translation of this method into the clinical setting promises to improve the management of patients by avoiding the use of unspecific imaging methodologies and reducing unnecessary thyroid surgery.
Collapse
|
16
|
Treatment of carcinoma in situ of the urinary bladder with an alpha-emitter immunoconjugate targeting the epidermal growth factor receptor: a pilot study. Eur J Nucl Med Mol Imaging 2018; 45:1364-1371. [DOI: 10.1007/s00259-018-4003-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/23/2018] [Indexed: 02/03/2023]
|
17
|
Abstract
SummaryAim: We investigated the impact of photon attenuation in myocardial perfusion imaging with SPECT and PET in patients with coronary artery disease. In fact, the regional tracer distribution can be quantitatively assessed by polar map analysis if the effects of photon attenuation are accounted for. PET imaging permits accurate measurement of and correction for photon attenuation, whereas results of attenuation correction in SPECT imaging have been inconsistent. Patients, methods: We compared photon attenuation in resting perfusion imaging studies with SPECT (99mTc-sestamibi) and PET (13N-ammonia) from 21 patients. Transaxial images were reconstructed with and without attenuation correction and reoriented into short axis images. Polar map analysis was utilized to generate regional tracer uptake in six anatomical segments. Results: Average segmental photon attenuation calculated as the ratio of counts in corrected and uncorrected images was 7.2 ± 1.4 in SPECT and 14.0 ± 3.1 in PET imaging (p <0.01). This attenuation factor was significantly related to body mass index for both methods (p <0.001). While attenuation correction for SPECT imaging did compensate for attenuation effects in the inferior wall (from –15% to +6% vs. PET), relative tracer uptake in the anterior wall in SPECT images was significantly reduced after attenuation correction (from –2% to –18% vs. PET, p <0.01). Conclusion: Differential effects of attenuation correction for myocardial SPECT perfusion imaging need to be considered when algorithms designed to compensate effects of photon attenuation in SPECT imaging are employed in clinical practice.
Collapse
|
18
|
In-depth Characterization of a TCR-specific Tracer for Sensitive Detection of Tumor-directed Transgenic T Cells by Immuno-PET. Am J Cancer Res 2017; 7:2402-2416. [PMID: 28744323 PMCID: PMC5525745 DOI: 10.7150/thno.17994] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/22/2017] [Indexed: 12/19/2022] Open
Abstract
A number of different technologies have been developed to monitor in vivo the distribution of gene-modified T cells used in immunotherapy. Nevertheless, in-depth characterization of novel approaches with respect to sensitivity and clinical applicability are so far missing. We have previously described a novel method to track engineered human T cells in tumors using 89Zr-Df-aTCRmu-F(ab')2 targeting the murinized part of the TCR beta domain (TCRmu) of a transgenic TCR. Here, we performed an in-depth in vitro characterization of the tracer in terms of antigen affinity, immunoreactivity, influence on T-cell functionality and stability in vitro and in vivo. Of particular interest, we have developed diverse experimental settings to quantify TCR-transgenic T cells in vivo. Local application of 89Zr-Df-aTCRmu-F(ab')2-labeled T cells in a spot-assay revealed signal detection down to approximately 1.8x104 cells. In a more clinically relevant model, NSG mice were intravenously injected with different numbers of transgenic T cells, followed by injection of the 89Zr-Df-aTCRmu-F(ab')2 tracer, PET/CT imaging and subsequent ex vivo T-cell quantification in the tumor. Using this setting, we defined a comparable detection limit of 1.0x104 T cells. PET signals correlated well to total numbers of transgenic T cells detected ex vivo independently of the engraftment rates observed in different individual experiments. Thus, these findings confirm the high sensitivity of our novel PET/CT T-cell tracking method and provide critical information about the quantity of transgenic T cells in the tumor environment suggesting our technology being highly suitable for further clinical translation.
Collapse
|
19
|
|
20
|
A multi-centre evaluation of eleven clinically feasible brain PET/MRI attenuation correction techniques using a large cohort of patients. Neuroimage 2016; 147:346-359. [PMID: 27988322 PMCID: PMC6818242 DOI: 10.1016/j.neuroimage.2016.12.010] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/14/2016] [Accepted: 12/05/2016] [Indexed: 01/27/2023] Open
Abstract
AIM To accurately quantify the radioactivity concentration measured by PET, emission data need to be corrected for photon attenuation; however, the MRI signal cannot easily be converted into attenuation values, making attenuation correction (AC) in PET/MRI challenging. In order to further improve the current vendor-implemented MR-AC methods for absolute quantification, a number of prototype methods have been proposed in the literature. These can be categorized into three types: template/atlas-based, segmentation-based, and reconstruction-based. These proposed methods in general demonstrated improvements compared to vendor-implemented AC, and many studies report deviations in PET uptake after AC of only a few percent from a gold standard CT-AC. Using a unified quantitative evaluation with identical metrics, subject cohort, and common CT-based reference, the aims of this study were to evaluate a selection of novel methods proposed in the literature, and identify the ones suitable for clinical use. METHODS In total, 11 AC methods were evaluated: two vendor-implemented (MR-ACDIXON and MR-ACUTE), five based on template/atlas information (MR-ACSEGBONE (Koesters et al., 2016), MR-ACONTARIO (Anazodo et al., 2014), MR-ACBOSTON (Izquierdo-Garcia et al., 2014), MR-ACUCL (Burgos et al., 2014), and MR-ACMAXPROB (Merida et al., 2015)), one based on simultaneous reconstruction of attenuation and emission (MR-ACMLAA (Benoit et al., 2015)), and three based on image-segmentation (MR-ACMUNICH (Cabello et al., 2015), MR-ACCAR-RiDR (Juttukonda et al., 2015), and MR-ACRESOLUTE (Ladefoged et al., 2015)). We selected 359 subjects who were scanned using one of the following radiotracers: [18F]FDG (210), [11C]PiB (51), and [18F]florbetapir (98). The comparison to AC with a gold standard CT was performed both globally and regionally, with a special focus on robustness and outlier analysis. RESULTS The average performance in PET tracer uptake was within ±5% of CT for all of the proposed methods, with the average±SD global percentage bias in PET FDG uptake for each method being: MR-ACDIXON (-11.3±3.5)%, MR-ACUTE (-5.7±2.0)%, MR-ACONTARIO (-4.3±3.6)%, MR-ACMUNICH (3.7±2.1)%, MR-ACMLAA (-1.9±2.6)%, MR-ACSEGBONE (-1.7±3.6)%, MR-ACUCL (0.8±1.2)%, MR-ACCAR-RiDR (-0.4±1.9)%, MR-ACMAXPROB (-0.4±1.6)%, MR-ACBOSTON (-0.3±1.8)%, and MR-ACRESOLUTE (0.3±1.7)%, ordered by average bias. The overall best performing methods (MR-ACBOSTON, MR-ACMAXPROB, MR-ACRESOLUTE and MR-ACUCL, ordered alphabetically) showed regional average errors within ±3% of PET with CT-AC in all regions of the brain with FDG, and the same four methods, as well as MR-ACCAR-RiDR, showed that for 95% of the patients, 95% of brain voxels had an uptake that deviated by less than 15% from the reference. Comparable performance was obtained with PiB and florbetapir. CONCLUSIONS All of the proposed novel methods have an average global performance within likely acceptable limits (±5% of CT-based reference), and the main difference among the methods was found in the robustness, outlier analysis, and clinical feasibility. Overall, the best performing methods were MR-ACBOSTON, MR-ACMAXPROB, MR-ACRESOLUTE and MR-ACUCL, ordered alphabetically. These methods all minimized the number of outliers, standard deviation, and average global and local error. The methods MR-ACMUNICH and MR-ACCAR-RiDR were both within acceptable quantitative limits, so these methods should be considered if processing time is a factor. The method MR-ACSEGBONE also demonstrates promising results, and performs well within the likely acceptable quantitative limits. For clinical routine scans where processing time can be a key factor, this vendor-provided solution currently outperforms most methods. With the performance of the methods presented here, it may be concluded that the challenge of improving the accuracy of MR-AC in adult brains with normal anatomy has been solved to a quantitatively acceptable degree, which is smaller than the quantification reproducibility in PET imaging.
Collapse
|
21
|
Segmental quantitative myocardial perfusion with PET for the detection of significant coronary artery disease in patients with stable angina. Eur J Nucl Med Mol Imaging 2016; 43:1522-9. [DOI: 10.1007/s00259-016-3362-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 03/07/2016] [Indexed: 12/21/2022]
|
22
|
Multicentre multi-device hybrid imaging study of coronary artery disease: results from the EValuation of INtegrated Cardiac Imaging for the Detection and Characterization of Ischaemic Heart Disease (EVINCI) hybrid imaging population. Eur Heart J Cardiovasc Imaging 2016; 17:951-60. [PMID: 26992419 DOI: 10.1093/ehjci/jew038] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/14/2016] [Indexed: 12/18/2022] Open
Abstract
AIMS Hybrid imaging provides a non-invasive assessment of coronary anatomy and myocardial perfusion. We sought to evaluate the added clinical value of hybrid imaging in a multi-centre multi-vendor setting. METHODS AND RESULTS Fourteen centres enrolled 252 patients with stable angina and intermediate (20-90%) pre-test likelihood of coronary artery disease (CAD) who underwent myocardial perfusion scintigraphy (MPS), CT coronary angiography (CTCA), and quantitative coronary angiography (QCA) with fractional flow reserve (FFR). Hybrid MPS/CTCA images were obtained by 3D image fusion. Blinded core-lab analyses were performed for CTCA, MPS, QCA and hybrid datasets. Hemodynamically significant CAD was ruled-in non-invasively in the presence of a matched finding (myocardial perfusion defect co-localized with stenosed coronary artery) and ruled-out with normal findings (both CTCA and MPS normal). Overall prevalence of significant CAD on QCA (>70% stenosis or 30-70% with FFR≤0.80) was 37%. Of 1004 pathological myocardial segments on MPS, 246 (25%) were reclassified from their standard coronary distribution to another territory by hybrid imaging. In this respect, in 45/252 (18%) patients, hybrid imaging reassigned an entire perfusion defect to another coronary territory, changing the final diagnosis in 42% of the cases. Hybrid imaging allowed non-invasive CAD rule-out in 41%, and rule-in in 24% of patients, with a negative and positive predictive value of 88% and 87%, respectively. CONCLUSION In patients at intermediate risk of CAD, hybrid imaging allows non-invasive co-localization of myocardial perfusion defects and subtending coronary arteries, impacting clinical decision-making in almost one every five subjects.
Collapse
|
23
|
Poster Session 1: Sunday 3 May 2015, 08:30-18:00 * Room: Poster Area. Eur Heart J Cardiovasc Imaging 2015. [DOI: 10.1093/ehjci/jev051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
24
|
|
25
|
Moderated Poster Session 4: Monday 4 May 2015, 15:30-16:30 * Room: Moderated Poster Area. Eur Heart J Cardiovasc Imaging 2015. [DOI: 10.1093/ehjci/jev050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
26
|
FIRST IN MAN OBSERVATIONS WITH SIMULTANEOUS 18F-FDG PET AND MR IMAGING IN PERIPHERAL ARTERY DISEASE USING A WHOLE-BODY INTEGRATED SCANNER. J Am Coll Cardiol 2015. [DOI: 10.1016/s0735-1097(15)61078-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
27
|
Detection of Significant Coronary Artery Disease by Noninvasive Anatomical and Functional Imaging. Circ Cardiovasc Imaging 2015; 8:CIRCIMAGING.114.002179. [DOI: 10.1161/circimaging.114.002179] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
28
|
A New Integrated Clinical-Biohumoral Model to Predict Functionally Significant Coronary Artery Disease in Patients With Chronic Chest Pain. Can J Cardiol 2015; 31:709-16. [PMID: 26022987 DOI: 10.1016/j.cjca.2015.01.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/23/2015] [Accepted: 01/29/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND In patients with chronic angina-like chest pain, the probability of coronary artery disease (CAD) is estimated by symptoms, age, and sex according to the Genders clinical model. We investigated the incremental value of circulating biomarkers over the Genders model to predict functionally significant CAD in patients with chronic chest pain. METHODS In 527 patients (60.4 years, standard deviation, 8.9 years; 61.3% male participants) enrolled in the European Evaluation of Integrated Cardiac Imaging (EVINCI) study, clinical and biohumoral data were collected. RESULTS Functionally significant CAD-ie, obstructive coronary disease seen at invasive angiography causing myocardial ischemia at stress imaging or associated with reduced fractional flow reserve (FFR < 0.8), or both-was present in 15.2% of patients. High-density lipoprotein (HDL) cholesterol, aspartate aminotransferase (AST) levels, and high-sensitivity C-reactive protein (hs-CRP) were the only independent predictors of disease among 31 biomarkers analyzed. The model integrating these biohumoral markers with clinical variables outperformed the Genders model by receiver operating characteristic curve (ROC) (area under the curve [AUC], 0.70 [standard error (SE), 0.03] vs 0.58 [SE, 0.03], respectively, P < 0.001) and reclassification analysis (net reclassification improvement, 0.15 [SE, 0.07]; P = 0.04). Cross-validation of the ROC analysis confirmed the discrimination ability of the new model (AUC, 0.66). As many as 56% of patients who were assigned to a higher pretest probability by the Genders model were correctly reassigned to a low probability class (< 15%) by the new integrated model. CONCLUSIONS The Genders model has a low accuracy for predicting functionally significant CAD. A new model integrating HDL cholesterol, AST, and hs-CRP levels with common clinical variables has a higher predictive accuracy for functionally significant CAD and allows the reclassification of patients from an intermediate/high to a low pretest likelihood of CAD.
Collapse
|
29
|
Abstract
BACKGROUND AND PURPOSE Inter- and intratumor heterogeneity and the variable course of disease in patients with glioma motivate the investigation of new prognostic factors to optimize individual treatment. Here we explore the usefulness of standard static and more sophisticated dynamic (18)F-fluoroethyltyrosine-PET imaging for the assessment of patient prognosis. MATERIALS AND METHODS Thirty-four consecutive patients with untreated, first-diagnosed, histologically proved glioma were included in this retrospective study. All patients underwent dynamic PET scans before surgery (± standard treatment) and were followed up clinically and by MR imaging. Static and dynamic tumor-to-background ratio, TTP, and slope-to-peak were obtained and correlated with progression-free survival. RESULTS Twenty of 34 patients experienced progression, with a median progression-free survival of 28.0 ± 11.1 months. Dynamic TTP was highly prognostic for recurrent disease, showing a strong correlation with progression-free survival (hazard ratio, 6.050; 95% CI, 2.11-17.37; P < .001). Most interesting, this correlation also proved significant in the subgroup of low-grade glioma (hazard ratio, 5.347; 95% CI, 1.05-27.20; P = .044), but not when using established static imaging parameters, such as maximum tumor-to-background ratio and mean tumor-to-background ratio. In the high-grade glioma subgroup, both dynamic and static parameters correlated with progression-free survival. The best results were achieved by defining ROIs around "hot spots" in earlier timeframes, underlining the concept of intratumor heterogeneity. CONCLUSIONS (18)F-fluoroethyltyrosine-PET can predict recurrence in patients with glioma, with dynamic analysis showing advantages over static imaging, especially in the low-grade subgroup.
Collapse
|
30
|
Self-gated radial MRI for respiratory motion compensation on hybrid PET/MR systems. ACTA ACUST UNITED AC 2014; 16:17-24. [PMID: 24505739 DOI: 10.1007/978-3-642-40760-4_3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Accurate localization and uptake quantification of lesions in the chest and abdomen using PET imaging is challenging due to the respiratory motion during the exam. The advent of hybrid PET/MR systems offers new ways to compensate for respiratory motion without exposing the patient to additional radiation. The use of self-gated reconstructions of a 3D radial stack-of-stars GRE acquisition is proposed to derive a high-resolution MRI motion model. The self-gating signal is used to perform respiratory binning of the simultaneously acquired PET raw data. Matching mu-maps are generated for every bin, and post-reconstruction registration is performed in order to obtain a motion-compensated PET volume from the individual gates. The proposed method is demonstrated in-vivo for three clinical patients. Motion-corrected reconstructions are compared against ungated and gated PET reconstructions. In all cases, motion-induced blurring of lesions in the liver and lung was substantially reduced, without compromising SNR as it is the case for gated reconstructions.
Collapse
|
31
|
Absolute myocardial flow quantification with (82)Rb PET/CT: comparison of different software packages and methods. Eur J Nucl Med Mol Imaging 2013; 41:126-35. [PMID: 23982454 DOI: 10.1007/s00259-013-2537-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/06/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE In clinical cardiac (82)Rb PET, globally impaired coronary flow reserve (CFR) is a relevant marker for predicting short-term cardiovascular events. However, there are limited data on the impact of different software and methods for estimation of myocardial blood flow (MBF) and CFR. Our objective was to compare quantitative results obtained from previously validated software tools. METHODS We retrospectively analyzed cardiac (82)Rb PET/CT data from 25 subjects (group 1, 62 ± 11 years) with low-to-intermediate probability of coronary artery disease (CAD) and 26 patients (group 2, 57 ± 10 years; P=0.07) with known CAD. Resting and vasodilator-stress MBF and CFR were derived using three software applications: (1) Corridor4DM (4DM) based on factor analysis (FA) and kinetic modeling, (2) 4DM based on region-of-interest (ROI) and kinetic modeling, (3) MunichHeart (MH), which uses a simplified ROI-based retention model approach, and (4) FlowQuant (FQ) based on ROI and compartmental modeling with constant distribution volume. RESULTS Resting and stress MBF values (in milliliters per minute per gram) derived using the different methods were significantly different: using 4DM-FA, 4DM-ROI, FQ, and MH resting MBF values were 1.47 ± 0.59, 1.16 ± 0.51, 0.91 ± 0.39, and 0.90 ± 0.44, respectively (P<0.001), and stress MBF values were 3.05 ± 1.66, 2.26 ± 1.01, 1.90 ± 0.82, and 1.83 ± 0.81, respectively (P<0.001). However, there were no statistically significant differences among the CFR values (2.15 ± 1.08, 2.05 ± 0.83, 2.23 ± 0.89, and 2.21 ± 0.90, respectively; P=0.17). Regional MBF and CFR according to vascular territories showed similar results. Linear correlation coefficient for global CFR varied between 0.71 (MH vs. 4DM-ROI) and 0.90 (FQ vs. 4DM-ROI). Using a cut-off value of 2.0 for abnormal CFR, the agreement among the software programs ranged between 76 % (MH vs. FQ) and 90 % (FQ vs. 4DM-ROI). Interobserver agreement was in general excellent with all software packages. CONCLUSION Quantitative assessment of resting and stress MBF with (82)Rb PET is dependent on the software and methods used, whereas CFR appears to be more comparable. Follow-up and treatment assessment should be done with the same software and method.
Collapse
|
32
|
PET/MR in prostate cancer: technical aspects and potential diagnostic value. Eur J Nucl Med Mol Imaging 2013; 40 Suppl 1:S79-88. [DOI: 10.1007/s00259-013-2445-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 04/29/2013] [Indexed: 01/29/2023]
|
33
|
Multimodal assessment of in vivo metabolism with hyperpolarized [1-13C]MR spectroscopy and 18F-FDG PET imaging in hepatocellular carcinoma tumor-bearing rats. J Nucl Med 2013; 54:1113-9. [PMID: 23596002 DOI: 10.2967/jnumed.112.110825] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Abnormalities of tumor metabolism can be exploited for molecular imaging. PET imaging of (18)F-FDG is a well-established method using the avid glucose uptake of tumor cells. (13)C MR spectroscopic imaging (MRSI) of hyperpolarized [1-(13)C]pyruvate and its metabolites, meanwhile, represents a new method to study energy metabolism by visualizing, for example, the augmented lactate dehydrogenase activity in tumor cells. Because of rapid signal loss, this method underlies strict temporal limitations, and the acquisition of data-encoding spatial, temporal, and spectral information within this time frame-is challenging. The object of our study was to compare spectroscopic images with (18)F-FDG PET images for visualizing tumor metabolism in a rat model. METHODS (13)C MRSI with IDEAL (Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation) chemical shift imaging in combination with single-shot spiral acquisition was used to obtain dynamic data from 23 rats bearing a subcutaneous hepatocellular carcinoma and from reference regions of the same animals. Static and dynamic analysis of (18)F-FDG PET images of the same animals was performed. The data were analyzed qualitatively (visual assessment) and quantitatively (magnitude and dynamics of (18)F-FDG uptake, (13)C MRSI dynamics, and physiologic parameters). RESULTS In most animals increased [1-(13)C]lactate signals in the tumor could be detected by simple display of integrated [1-(13)C]lactate images with corresponding enhanced (18)F-FDG uptake. Low [1-(13)C]pyruvate or [1-(13)C]lactate signals did not correlate with histologic or physiologic parameters. Significantly less pyruvate reached the tumors than the gastrointestinal tract, but in tumors a significantly higher amount of pyruvate was converted to lactate and alanine within seconds after intravenous administration. CONCLUSION This study reveals that PET and (13)C MRSI can be used to visualize increased glycolytic flux in malignant tissue. The combination of signals will allow the quantitative dissection of substrate metabolism, with respect to uptake and downstream metabolic pathways. Although hyperpolarized [1-(13)C]pyruvate increases the sensitivity of MR imaging, signal-to-noise ratio constraints still apply for spatially and temporally resolved (13)C MRSI, emphasizing the need for further MR methodologic development. These first imaging data suggest the feasibility of (13)C MRSI for future clinical use.
Collapse
|
34
|
|
35
|
Cardiac PET/CT misregistration causes significant changes in estimated myocardial blood flow. J Nucl Med 2012; 54:50-4. [PMID: 23090213 DOI: 10.2967/jnumed.112.108183] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Misregistration of cardiac PET/CT data can lead to misinterpretation of regional myocardial perfusion. However, the effect of misregistration on the quantification of myocardial blood flow (MBF) has not been studied. METHODS Cardiac (82)Rb-PET/CT scans of 10 patients with normal regional myocardial perfusion were analyzed. Realignment was done for the baseline and stress PET/CT images as necessary, and MBF was obtained from dynamic data. Then, the stress images were misregistered by 5 mm along the x-axis (left) and z-axis (cranial) and again by 10 mm. A 10-mm misregistration in the opposite direction (-10 mm along the x-axis [right] and z-axis [caudal]) was also tested. Stress MBF was recalculated for 5-, 10-, and -10-mm misregistrations. RESULTS Stress MBF of the left ventricle decreased by 10% ± 6% (P = 0.005) after 5-mm misregistration and by 24% ± 15% (P = 0.001) after 10-mm misregistration. In descending order, the most important stress MBF changes occurred in the anterior (39% ± 9%), lateral (34% ± 9%), apical (20% ± 16%), inferior (12% ± 10%), and septal (10% ± 12%) walls after 10-mm misregistration. Lesser changes were observed after 5-mm misregistration, with the same wall distribution. In contrast, -10-mm misregistration increased global MBF by 9% ± 6% (P = 0.004). In descending order, the overestimation of estimated MBF after -10-mm misregistration occurred in the lateral (15% ± 8%), apical (15% ± 18%), anterior (9% ± 5%), and inferior (9% ± 11%) walls. CONCLUSION Misregistration of the stress PET/CT dataset leads to significant global and regional artifactual alterations in the estimated MBF. Quantitative error was observed throughout the myocardium and was not confined to those heart regions that extended into the lung on misregistered CT.
Collapse
|
36
|
|
37
|
Fast Multiple Organ Detection and Localization in Whole-Body MR Dixon Sequences. LECTURE NOTES IN COMPUTER SCIENCE 2011; 14:239-47. [DOI: 10.1007/978-3-642-23626-6_30] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
38
|
Electrocardiogram-gated 18F-FDG PET/CT hybrid imaging in patients with unsatisfactory response to cardiac resynchronization therapy: initial clinical results. J Nucl Med 2010; 52:67-71. [PMID: 21149479 DOI: 10.2967/jnumed.110.078709] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The present study aimed to distinguish responders to cardiac resynchronization therapy (CRT) from nonresponders, using electrocardiogram-gated 18F-FDG PET/CT. METHODS Seven consecutive CRT nonresponders were included in the study, along with 7 age- and sex-matched CRT responders, serving as reference material. Therapy response was defined as clinical improvement (≥1 New York Heart Association class) and evidence of reverse remodeling. Besides PET/CT, we measured brain natriuretic peptide levels and assessed dyssynchrony using transthoracic echocardiography. RESULTS Compared with nonresponders, CRT responders showed significant differences in the declines of left-ventricular end-systolic volume and brain natriuretic peptide and in left-ventricular dyssynchrony (global left-ventricular entropy), extent of the myocardial scar burden, and biventricular pacemaker leads positioned within viable myocardial regions. Among the nonresponders, further therapy management was guided by the PET/CT results in 4 of 7 patients. CONCLUSION Cardiac hybrid imaging using gated 18F-FDG PET/CT enabled the identification of potential reasons for nonresponse to CRT therapy, which can guide subsequent therapy.
Collapse
|
39
|
Hybrid-Verfahren in der kardiologischen Bildgebung. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1252512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
40
|
Monte Carlo simulations of the count rate performance of a clinical whole-body MR/PET scanner. Med Phys 2009; 36:4126-35. [DOI: 10.1118/1.3193676] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
41
|
A phantom assessment of cold stomach-related artifacts in myocardial perfusion imaging. Nucl Med Commun 2009; 30:569-73. [DOI: 10.1097/mnm.0b013e32832c79ce] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
42
|
|
43
|
Abstract
In view of the commercial success of integrated PET/CT scanners, there is an increasing interest in comparable SPECT/CT systems. SPECT in combination with CT enables a direct correlation of anatomic information and functional information, resulting in better localization and definition of scintigraphic findings. Besides anatomic referencing, the added value of CT coregistration is based on the attenuation correction capabilities of CT. The number of clinical studies is limited, but pilot studies have indicated a higher specificity and a significant reduction in indeterminate findings. The superiority of SPECT/CT over planar imaging or SPECT has been demonstrated in bone scintigraphy, somatostatin receptor scintigraphy, parathyroid scintigraphy, and adrenal gland scintigraphy. Also, rates of detection of sentinel nodes by biopsy can be increased with SPECT/CT. This review highlights recent technical developments in integrated SPECT/CT systems and summarizes the current literature on potential clinical uses and future directions for SPECT/CT in cardiac, neurologic, and oncologic applications.
Collapse
|
44
|
In vivo molecular imaging of angiogenesis, targeting alphavbeta3 integrin expression, in a patient after acute myocardial infarction. Eur Heart J 2008; 29:2201. [PMID: 18375397 DOI: 10.1093/eurheartj/ehn129] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
45
|
N-terminal pro-brain natriuretic peptide on admission in patients with acute myocardial infarction and correlation with scintigraphic infarct size, efficacy of reperfusion, and prognosis. Am J Cardiol 2006; 97:1151-6. [PMID: 16616017 DOI: 10.1016/j.amjcard.2005.11.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 11/01/2005] [Accepted: 11/01/2005] [Indexed: 11/16/2022]
Abstract
We investigated whether N-terminal pro-brain natriuretic peptide (NT-pro-BNP) that was measured on admission in patients with acute myocardial infarction (AMI) predicts the efficacy of reperfusion or whether NT-pro-BNP provides prognostic information independent of infarct size as estimated by single-photon emission computed tomographic scintigraphy. The study included 174 patients with ST-segment elevation AMI who were admitted within 24 hours of pain onset. NT-pro-BNP level was measured on admission. Paired scintigraphic studies (before and 7 to 14 days after reperfusion) were performed to assess infarct size and define myocardial salvage. One-year clinical follow-up was assessed. Patients were categorized into the high NT-pro-BNP group (57 patients in the upper tertile of NT-pro-BNP) and low NT-pro-BNP group (117 patients in the middle and lower tertiles of NT-pro-BNP). Initial median perfusion defect was 35.0% (interquartile rage 20.0 to 53.0%) of the left ventricle in the high NT-pro-BNP group versus 19.0% (interquartile range 10.0 to 32.2) of the left ventricle in the low NT-pro-BNP group (p <0.001). Median salvage index was 0.36 (interquartile range 0.16 to 0.86) in the high NT-pro-BNP group versus 0.53 (interquartile range 0.31 to 0.75) in the low NT-pro-BNP group (p = 0.22). After adjustment in Cox's proportional hazards model, NT-pro-BNP remained an independent correlate of 1-year mortality (adjusted hazard ratio 2.31, 95% confidence interval 1.09 to 4.89, p = 0.03, high vs low NT-pro-BNP group). In conclusion, NT-pro-BNP measured on admission in patients with AMI correlates with scintigraphic area at risk and predicts prognosis but does not predict the efficacy of mechanical reperfusion by stenting or angioplasty.
Collapse
|
46
|
Attenuation correction for myocardial perfusion imaging. A comparison between SPECT and PET imaging by polar map analysis. Nuklearmedizin 2006; 45:171-6. [PMID: 16964343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
AIM We investigated the impact of photon attenuation in myocardial perfusion imaging with SPECT and PET in patients with coronary artery disease. In fact, the regional tracer distribution can be quantitatively assessed by polar map analysis if the effects of photon attenuation are accounted for. PET imaging permits accurate measurement of and correction for photon attenuation, whereas results of attenuation correction in SPECT imaging have been inconsistent. PATIENTS, METHODS We compared photon attenuation in resting perfusion imaging studies with SPECT ((99m)Tc-sestamibi) and PET ((13)N-ammonia) from 21 patients. Transaxial images were reconstructed with and without attenuation correction and reoriented into short axis images. Polar map analysis was utilized to generate regional tracer uptake in six anatomical segments. RESULTS Average segmental photon attenuation calculated as the ratio of counts in corrected and uncorrected images was 7.2 +/- 1.4 in SPECT and 14.0 +/- 3.1 in PET imaging (p < 0.01). This attenuation factor was significantly related to body mass index for both methods (p < 0.001). While attenuation correction for SPECT imaging did compensate for attenuation effects in the inferior wall (from -15% to +6% vs. PET), relative tracer uptake in the anterior wall in SPECT images was significantly reduced after attenuation correction (from -2% to -18% vs. PET, p < 0.01). CONCLUSION Differential effects of attenuation correction for myocardial SPECT perfusion imaging need to be considered when algorithms designed to compensate effects of photon attenuation in SPECT imaging are employed in clinical practice.
Collapse
|
47
|
13N-ammonia rest/stress PET. Nuklearmedizin 2006. [DOI: 10.1055/s-0038-1625122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
SummaryAim: Hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST). Patients, methods: Twelve patients with CAD underwent rest/adenosine 13N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day). Results: Folate levels increased from 21 ± 6 to 210 ± 34 μg/l (+900%, p <0.0001) while Hcy levels decreased from 12.1 ± 3.6 to 9.1 ± 3.1 μmol/l (–25%; p <0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 ± 0.93 to 3.25 ± 1.15 ml/ g/min; p = 0.05) and CFR (from 3.00 ± 0.76 to 3.72 ± 0.93 ml/g/min; p <0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 μmol/l). An inverse relation was found between Hcy and CFR (R = –0.53; p = 0.08) and between Hcy and MBF at rest (R = –0.62; p < 0.05) at baseline conditions, not persisting after FAST. Conclusion: Coronary vascular reactivity can be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy.
Collapse
|
48
|
13N-ammonia rest/stress PET: folic acid improves global coronary vasoreactivity in coronary artery disease patients with normal or elevated homocysteine levels. Nuklearmedizin 2006; 45:248-53. [PMID: 17149493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
AIM Hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST). PATIENTS, METHODS Twelve patients with CAD underwent rest/adenosine (13) N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day). RESULTS Folate levels increased from 21 +/- 6 to 210 +/- 34 microg/l (+900%, p < 0.0001) while Hcy levels decreased from 12.1 +/- 3.6 to 9.1 +/- 3.1 micromol/l ( - 25%; p < 0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 +/- 0.93 to 3.25 +/- 1.15 ml/g/min; p = 0.05) and CFR (from 3.00 +/- 0.76 to 3.72 +/- 0.93 ml/g/min; p < 0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 micromol/l). An inverse relation was found between Hcy and CFR (R = - 0.53; p = 0.08) and between Hcy and MBF at rest (R = - 0.62; p < 0.05) at baseline conditions, not persisting after FAST. CONCLUSION Coronary vascular reactivity can be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy.
Collapse
|
49
|
PET/CT in der Herzbildung: Integration von Funktion und Morphologie. ROFO-FORTSCHR RONTG 2005. [DOI: 10.1055/s-2005-867210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
50
|
Myocardial salvage after reduced-dose thrombolysis combined with glycoprotein IIb/IIIa blockade versus thrombolysis alone in patients with acute myocardial infarction. J Thromb Thrombolysis 2004; 17:191-7. [PMID: 15353917 DOI: 10.1023/b:thro.0000040488.26414.9e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND The aim of study was to examine the efficacy of reduced-dose alteplase plus abciximab versus alteplase alone by quantifying the amount of myocardium salvaged using myocardial scintigraphy. METHODS This study analyzed 150 patients with acute myocardial infarction who received alteplase (69 patients) or reduced-dose alteplase plus abciximab (81 patients) in the setting of the Stent versus Thrombolysis for Occluded Coronary Arteries in Patients with Acute Myocardial Infarction (STOPAMI) 1 and 2 trials. Salvage index (proportion of initial perfusion defect salvaged by reperfusion therapy), which was obtained by paired scintigraphic studies performed 7-14 days apart, was the primary endpoint of the study. One-year clinical follow-up was also done. RESULTS Salvage index did not differ significantly among patients treated with reduced-dose alteplase plus abciximab (median, 0.41 [25th; 75th percentiles: 0.13; 0.58]) compared to patients who received alteplase (0.26 [0.09; 0.61], p = 0.30). Final infarct size was 16.0% [4.0; 31.0] of the left ventricle in the group with reduced-dose alteplase plus abciximab and 19.4% [7.9; 34.2] of left ventricle in the group with alteplase (p = 0.44). Within a time-to-admission interval of <2 hours, there was a trend for higher values of salvage index in patients who received reduced-dose alteplase plus abciximab compared with patients who received alteplase (0.55 [0.35; 0.73] versus 0.29 [0.11; 0.69], p = 0.15). For time-to-admission intervals > or = 2 hours, no such trend was observed between those who received reduced-dose alteplase plus abciximab or alteplase (0.25 [0.08; 0.48] versus 0.22 [0.08; 0.46], p = 0.79). Major bleeding occurred in 4 patients (5.0%) in the group with reduced-dose alteplase plus abciximab versus 2 patients (3.0%) in the group with alteplase alone (p = 0.58). CONCLUSION When used as a general strategy in patients with acute myocardial infarction, adding abciximab to alteplase does not increase significantly the amount of salvaged myocardium as compared with alteplase alone. Combination therapy may offer advantages over thrombolytic agents alone if such therapy is applied within 2 hours from symptom onset; however these data need to be proven by studies of adequate power.
Collapse
|