1
|
de Nijs R, Berg RMG, Lindskov Hansen S, Mortensen J. Ventilation perfusion functional difference images in lung SPECT: A linear and symmetrical scale as an alternative to the ventilation perfusion ratio. Phys Med 2024; 119:103306. [PMID: 38335743 DOI: 10.1016/j.ejmp.2024.103306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
PURPOSE Ventilation Perfusion SPECT is important in the diagnostics of e.g. pulmonary embolism and chronic obstructive pulmonary disease. Classical and reverse mismatched defects can be identified by utilizing the ventilation-perfusion ratio. Unfortunately, this ratio is only linear in the ventilation, the scale is not symmetrical regarding classical and reversed mismatches and small perfusion values give rise to artifacts. The ventilation-perfusion (VQ) difference is developed as an alternative. METHODS For both VQ-ratio and VQ-difference a scaling factor for the perfusion is computed, so that voxels with matched ventilation and perfusion (on average) yield zero signal. The relative VQ-difference is calculated by scaling with the summed VQ-signal in each voxel. The scaled VQ-difference is calculated by scaling with the global maximum of this sum. RESULTS The relative and scaled differences have a scale from -1 (perfusion only) to + 1 (ventilation only). Image quality of relative VQ-difference and VQ-ratio images is hampered by artifacts from areas with both low perfusion and low ventilation. Ratio and differences have been investigated in ten patients and are shown for three patients (one without defects). Clinical thresholds for the difference images are derived resulting in color maps of relevant (reversed) mismatches with a (reciprocal) ratio larger than two. CONCLUSIONS The relative ventilation-perfusion difference is a methodological improvement on the ventilation-perfusion ratio, because it has a symmetrical scale and is bound on a closed domain. A better diagnostic value is expected by utilizing the scaled difference, which represents functional difference instead of relative difference.
Collapse
Affiliation(s)
- Robin de Nijs
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
| | - Ronan M G Berg
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Physical Activity Research, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Sofie Lindskov Hansen
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Jann Mortensen
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Medicine, The National Hospital, Torshavn, Faroe Islands
| |
Collapse
|
2
|
Sjögreen-Gleisner K, Flux G, Bacher K, Chiesa C, de Nijs R, Kagadis GC, Lima T, Georgosopoulou ML, Gabiña PM, Nekolla S, Peters S, Santos J, Sattler B, Stokke C, Tran-Gia J, Gilligan P, Bardiès M. 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] [What about the content of this article? (0)] [Affiliation(s)] [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
Affiliation(s)
| | - Glenn Flux
- Joint Department of Physics, Royal Marsden Hospital and Institute of Cancer Research, Sutton, Surrey, UK
| | - Klaus Bacher
- Medical Physics, Ghent University, Ghent, Belgium
| | - Carlo Chiesa
- Nuclear Medicine, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Robin de Nijs
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - George C Kagadis
- 3DMI Research Group, Department of Medical Physics, University of Patras, Rion, Greece
| | - Thiago Lima
- Department of Radiology and Nuclear Medicine, Luzerner Kantonsspital, Lucerne, Switzerland/Faculty of Health Sciences and Medicine, University of Lucerne, Switzerland
| | | | - Pablo Minguez Gabiña
- Department of Medical Physics and Radiation Protection, Gurutzeta-Cruces University Hospital /Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Stephan Nekolla
- School of Medicine and Health, Department of Nuclear Medicine, Technical University Munich, Munich, Germany
| | - Steffie Peters
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joao Santos
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center, Portuguese Oncology Institute of Porto/Porto Comprehensive Cancer Center & Health Research Network, Porto, Portugal
| | - Bernhard Sattler
- Department of Nuclear Medicine, University of Leipzig Medical Centre, Leipzig, Germany
| | - Caroline Stokke
- Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway & Department of Physics, University of Oslo, Oslo, Norway
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Paddy Gilligan
- Mater Misericordiae University Hospital, Dublin, Ireland
| | - Manuel Bardiès
- IRCM, UMR 1194 INSERM, Université de Montpellier and Institut Régional du Cancer de Montpellier (ICM), France & Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier (ICM), France
| |
Collapse
|
3
|
de Nijs R. A novel model-based equation for size dependent mean recovery coefficients for spheres and other shapes. Phys Med 2023; 116:103174. [PMID: 38007296 DOI: 10.1016/j.ejmp.2023.103174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/10/2023] [Accepted: 11/16/2023] [Indexed: 11/27/2023] Open
Abstract
BACKGROUND In NM-imaging, theoretical curves for the recovery coefficient (RC) of the signal maximum and mean are known for spheres and cubes, if a 3D Gaussian PSF is assumed. The RC of the maximum is also known for cylinders. For these and other shapes empirical equations with one or two fit-parameters have been utilized. METHODS An equation for the RC for large objects of arbitrary shape is derived and generalized into an empirical equation for smaller objects, which is verified by numerical simulations. The proposed equation is compared to published results on SPECT kidney phantom measurements and to PET measurements on the NEMA IEC PET body phantom with six spheres. RESULTS The signal loss (1-RC) for large spheres is inversely proportional to the radius, where the slope is proportional to the FWHM of the spatial resolution. For non-spherical shapes the generalized instead of the volume equivalent radius should be utilized. For smaller objects, an equation with one added empirical fit-parameter is presented. It is demonstrated that the EANM-guidelines' two-parameter logistic function results in a poor fit if the theoretical slope and inverse proportionality are forced and it gives a suboptimal fit when both parameters are fitted. CONCLUSIONS A novel model-based equation for the mean RC-curve is derived. It can be used for arbitrary shapes as long as the sphericity is taken into account and it is accurate down to RC = 10 %. One parameter is directly related to the spatial resolution, while the other is a shape depending fit-parameter.
Collapse
Affiliation(s)
- Robin de Nijs
- Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
| |
Collapse
|
4
|
Helt TW, Buelund L, Borgwardt L, Eriksen T, Johansen L, de Nijs R, Holm S, Burrin DG, Thymann T, Christensen VB. Towards a model of biliary atresia - Pilot feasibility study in newborn piglets. Biochem Biophys Rep 2023; 34:101487. [PMID: 37265596 PMCID: PMC10230168 DOI: 10.1016/j.bbrep.2023.101487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/15/2023] [Accepted: 05/17/2023] [Indexed: 06/03/2023] Open
Abstract
Biliary atresia (BA) is a rare congenital liver disease with unknown etiology, and it is the most common indication for liver transplantation in children. As BA infants suffer from intestinal malabsorption and neurodevelopmental deficits, it is necessary to identify optimal medical and nutritional strategies using appropriate neonatal animal models. We aim to determine the feasibility of using newborn piglets with surgically induced cholestasis (bile duct ligation (BDL)) to mimic clinical features of BA. Six piglets were subjected to abdominal surgery on day 4 after birth. The bile ducts were ligated, and the piglet were followed for up to 12 days. On day 12 the piglets were subjected to a hepatobiliary scintigraphy using the tracer radiolabeled Technetium(99m-tc)-mebrofenin, and blood samples were collected for biochemical profiling. Of the six piglets, hepatobiliary scintigraphy verified that two piglets (BDL) had no excretion of bile into the duodenum, i.e. full cholestasis with a hepatic extraction fraction of 84-87% and clearance time of 230-318 min. One piglet (SHAM) had bile excretion to the duodenum. In accordance with this, the BDL piglets had steatorrhea, and increased levels of bilirubin and gammaglutamyl transferase (GGT). The last three piglets were euthanized due to bile leakage or poor growth. Surgically induced cholestasis in young piglets, may offer an animal model that displays clinical characteristics of biliary atresia, including malabsorption, hyperbilirubinaemia, increased GGT and reduced hepatic excretory function. Following refinement, this animal model may be used to optimize feeding strategies to secure optimal nutrition and neurodevelopment for neonatal cholestasis/BA patients.
Collapse
Affiliation(s)
- Thora Wesenberg Helt
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Lene Buelund
- Department of Veterinary Clinical Sciences, University of Copenhagen, Denmark
| | - Lise Borgwardt
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Denmark
| | - Lars Johansen
- Department of Pediatrics, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Robin de Nijs
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Soren Holm
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen University Hospital, Denmark
| | | | - Thomas Thymann
- Department of Veterinary and Animal Science, University of Copenhagen, Denmark
| | - Vibeke Brix Christensen
- Department of Pediatrics, Rigshospitalet, Copenhagen University Hospital, Denmark
- Department of Veterinary and Animal Science, University of Copenhagen, Denmark
| |
Collapse
|
5
|
de Nijs R, Sijtsema ND, Kruis MF, Jensen CV, Iversen M, Perch M, Mortensen J. Comparison of 81mKrypton and 99mTc-Technegas for ventilation single-photon emission computed tomography in severe chronic obstructive pulmonary disease. Nucl Med Commun 2021; 42:160-168. [PMID: 33105398 PMCID: PMC7808361 DOI: 10.1097/mnm.0000000000001314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/23/2020] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Ventilation and perfusion single-photon emission computed tomography combined with computed tomography (SPECT/CT) is a powerful tool to assess the state of the lungs in chronic obstructive pulmonary disease (COPD). 81mKrypton is a gaseous ventilation tracer and distributes similarly to air, but is not widely available and relatively expensive. 99mTc-Technegas is cheaper and has wider availability, but is an aerosol, which may deposit in hot spots as the severity of COPD increases. In this study, 81mKrypton and 99mTc-Technegas were compared quantitatively in patients with severe COPD. METHODS The penetration ratio, the heterogeneity index (with and without band filtering for relevant clinical sizes) and hot spot appearance were assessed in eleven patients with severe COPD that underwent simultaneous dual-isotope ventilation SPECT/CT with both 99mTc-Technegas and 81mKrypton. RESULTS Significant differences were found in the penetration ratio for the medium energy general purpose (MEGP) collimators, but not for the low energy general purpose (LEGP) collimators. The difference in the overall and the band filtered heterogeneity index was significant in most cases. All patients suffered from 99mTc-Technegas hot spots in at least one lung. Comparison of MEGP 81mKrypton and LEGP Technegas scans revealed similar results as the comparison for the MEGP collimators. CONCLUSION Caution should be taken when replacing 81mKrypton with 99mTc-Technegas as a ventilation tracer in patients with severe COPD as there are significant differences in the distribution of the tracers over the lungs. Furthermore, this patient group is prone to 99mTc-Technegas hot spots and might need additional scanning if hot spots severely hamper image interpretation.
Collapse
Affiliation(s)
- Robin de Nijs
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Nienke D. Sijtsema
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Physics and Astronomy, Faculty of Science, VU University, Amsterdam, The Netherlands
| | | | | | - Martin Iversen
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Michael Perch
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Jann Mortensen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| |
Collapse
|
6
|
Rasmussen T, de Nijs R, Kjær Olsen L, Kamper AL, Evi Bang L, Frimodt-Møller M, Kelbæk H, Schwartz Sørensen S, Kjær A, Feldt-Rasmussen B, Hastrup Svendsen J, Hasbak P. Renal 123I-MIBG Uptake before and after Live-Donor Kidney Transplantation. Diagnostics (Basel) 2020; 10:E802. [PMID: 33050245 PMCID: PMC7601882 DOI: 10.3390/diagnostics10100802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/01/2020] [Accepted: 10/07/2020] [Indexed: 12/30/2022] Open
Abstract
Increased sympathetic activity is suggested to be part of the pathogenesis in several diseases. Methods to evaluate sympathetic activity and renal nervous denervation procedural success are lacking. Scintigraphy using the norepinephrine analog Iodine-123 Metaiodobenzylguanidine (123I-MIBG) might provide information on renal sympathetic nervous activity. Renal transplantation induces complete denervation of the kidney and as such represents an ideal model to evaluate the renal 123I-MIBG scintigraphy method. The aim of this study was to evaluate whether renal 123I-MIBG scintigraphy can detect changes in renal sympathetic nervous activity following renal transplantation. Renal 123I-MIBG scintigraphy was performed in eleven renal transplant recipients at 1, 3, and 6 months following transplantation and in their respective living donors prior to their kidney donation. Relative uptake as well as washout was obtained. In transplanted patients, the relative 4 h uptake of 123I-MIBG, as measured by the kidney/background ratio, was 2.7 (0.4) (mean (SD)), 2.7 (0.5), and 2.5 (0.4) at 1, 3, and 6 months post-transplantation, respectively, as compared with the 4.0 (0.4) value in the donor kidney before donor nephrectomy (p < 0.01). There was no significant change in washout-rate between pre-transplantation and any of the follow-up time points. Living donor kidney transplantation was at 6 months post transplantation, associated with an almost 40% reduction in the relative 4 h 123I-MIBG uptake of the kidney. Further studies will help to fully establish its implications as a marker of renal innervation or denervation.
Collapse
Affiliation(s)
- Thomas Rasmussen
- Departments of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (R.d.N.); (A.K.); (P.H.)
| | - Robin de Nijs
- Departments of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (R.d.N.); (A.K.); (P.H.)
| | - Lene Kjær Olsen
- Department of Nephrology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (L.K.O.); (A.-L.K.); (S.S.S.); (B.F.-R.)
| | - Anne-Lise Kamper
- Department of Nephrology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (L.K.O.); (A.-L.K.); (S.S.S.); (B.F.-R.)
| | - Lia Evi Bang
- Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (L.E.B.); (J.H.S.)
| | | | - Henning Kelbæk
- Department of Cardiology, Zealand University Hospital, 4000 Roskilde, Denmark;
| | - Søren Schwartz Sørensen
- Department of Nephrology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (L.K.O.); (A.-L.K.); (S.S.S.); (B.F.-R.)
- Department of Clinical Medicine, Faculty of Health and Medical sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Andreas Kjær
- Departments of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (R.d.N.); (A.K.); (P.H.)
- Department of Clinical Medicine, Faculty of Health and Medical sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Bo Feldt-Rasmussen
- Department of Nephrology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (L.K.O.); (A.-L.K.); (S.S.S.); (B.F.-R.)
- Department of Clinical Medicine, Faculty of Health and Medical sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jesper Hastrup Svendsen
- Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (L.E.B.); (J.H.S.)
- Department of Clinical Medicine, Faculty of Health and Medical sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Philip Hasbak
- Departments of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (R.d.N.); (A.K.); (P.H.)
| |
Collapse
|
7
|
Hansen SL, de Nijs R, Mortensen J, Berg RMG. Ventilation-perfusion SPECT versus CTPA in young adult females with suspected pulmonary embolism. Eur Respir J 2020; 55:55/6/2000448. [PMID: 32527852 DOI: 10.1183/13993003.00448-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/15/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Sofie Lindskov Hansen
- Dept of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Robin de Nijs
- Dept of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Jann Mortensen
- Dept of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark.,Dept of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.,Dept of Medicine, The National Hospital, Torshavn, Faroe Islands
| | - Ronan M G Berg
- Dept of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, Denmark .,Dept of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Centre for Physical Activity Research, Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
8
|
Nielsen J, Nerup N, Møller S, de Nijs R, Rasmussen A, Bo Svendsen L, Kjaer MS, Brix Christensen V, Borgwardt L. Minimally invasive assessment of hepatic function in children with indocyanine green elimination: a validation study. Scand J Gastroenterol 2019; 54:485-491. [PMID: 30924709 DOI: 10.1080/00365521.2019.1591497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Objectives: Pediatric liver disease (PLD) covers a variety of etiologies and severities, from mild temporary illness to diseases with fatal outcomes. There is a demand for minimally invasive and reliable measures for assessment of the severity of PLD. Indocyanine green (ICG) elimination kinetics to estimate hepatic function has been used in adults for decades, however, due to invasiveness, the use in PLD is still limited. The aim of the present study was to evaluate minimally invasive estimation of ICG elimination by pulse spectrophotometry (ICGLi), in comparison with traditional spectrophotometry using serial blood samples (ICGbs). Methods: One hundred children aged 0-18 years were included in the study. ICG elimination kinetics was measured with ICGLi and ICGbs, and results compared by failure rates, mean difference, limits of agreement, Bland Altman plots and linear regression analysis. Plasma disappearance rates (PDRLi and PDRbs) were used for comparison. Results: One hundred and twelve simultaneous measurements in 87 patients were performed successfully. Mean difference for PDR (%/min) was 3.58 (95% CI 2.69; 4.47). Limits of agreement were -5.06; 12.22. A linear correlation between the two methods with a regression coefficient of 0.83 (SE 0.02 95% CI 0.80; 0.87) was found. For conversion we computed the following equation; PDRbs = 0.83 × PDRLi. Conclusions: The present study shows that ICG PDR can be obtained by a minimally invasive method and thus replace measures by serial blood samples in children with liver disease of different etiologies and severities. However, a systematic relative difference between the two methods exists. Our proposed correction factor needs to be validated in larger cohorts.
Collapse
Affiliation(s)
- Jon Nielsen
- a Department of Paediatrics and Adolescent Medicine , Copenhagen University Hospital Rigshospitalet , Copenhagen Ø , Denmark
| | - Nikolaj Nerup
- b Department of Surgical Gastroenterology and Transplantation , Copenhagen University Hospital Rigshospitalet , Copenhagen Ø , Denmark
| | - Søren Møller
- c Department of Clinical Physiology, Center of Functional Imaging and Research, Faculty of Health Sciences , Hvidovre Hospital , Hvidovre , Denmark.,d Faculty of Health and Medical Sciences, Department of Clinical Medicine, University of Copenhagen , Copenhagen , Denmark
| | - Robin de Nijs
- e Department of Clinical Physiology, Nuclear Medicine and PET , Copenhagen University Hospital, Rigshospitalet , Copenhagen Ø , Denmark
| | - Allan Rasmussen
- b Department of Surgical Gastroenterology and Transplantation , Copenhagen University Hospital Rigshospitalet , Copenhagen Ø , Denmark
| | - Lars Bo Svendsen
- b Department of Surgical Gastroenterology and Transplantation , Copenhagen University Hospital Rigshospitalet , Copenhagen Ø , Denmark
| | - Mette Skalshøi Kjaer
- f Department of Medical Gastroenterology and Hepatology , Copenhagen University Hospital Rigshospitalet , Copenhagen Ø , Denmark
| | - Vibeke Brix Christensen
- a Department of Paediatrics and Adolescent Medicine , Copenhagen University Hospital Rigshospitalet , Copenhagen Ø , Denmark
| | - Lise Borgwardt
- e Department of Clinical Physiology, Nuclear Medicine and PET , Copenhagen University Hospital, Rigshospitalet , Copenhagen Ø , Denmark
| |
Collapse
|
9
|
Tossici-Bolt L, Dickson JC, Sera T, Booij J, Asenbaun-Nan S, Bagnara MC, Borght TV, Jonsson C, de Nijs R, Hesse S, Koulibaly PM, Akdemir UO, Koole M, Tatsch K, Varrone A. [ 123I]FP-CIT ENC-DAT normal database: the impact of the reconstruction and quantification methods. EJNMMI Phys 2017; 4:8. [PMID: 28130765 PMCID: PMC5272851 DOI: 10.1186/s40658-017-0175-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/17/2017] [Indexed: 11/10/2022] Open
Abstract
Background [123I]FP-CIT is a well-established radiotracer for the diagnosis of dopaminergic degenerative disorders. The European Normal Control Database of DaTSCAN (ENC-DAT) of healthy controls has provided age and gender-specific reference values for the [123I]FP-CIT specific binding ratio (SBR) under optimised protocols for image acquisition and processing. Simpler reconstruction methods, however, are in use in many hospitals, often without implementation of attenuation and scatter corrections. This study investigates the impact on the reference values of simpler approaches using two quantifications methods, BRASS and Southampton, and explores the performance of the striatal phantom calibration in their harmonisation. Results BRASS and Southampton databases comprising 123 ENC-DAT subjects, from gamma cameras with parallel collimators, were reconstructed using filtered back projection (FBP) and iterative reconstruction OSEM without corrections (IRNC) and compared against the recommended OSEM with corrections for attenuation and scatter and septal penetration (ACSC), before and after applying phantom calibration. Differences between databases were quantified using the percentage difference of their SBR in the dopamine transporter-rich striatum, with their significance determined by the paired t test with Bonferroni correction. Attenuation and scatter losses, measured from the percentage difference between IRNC and ACSC databases, were of the order of 47% for both BRASS and Southampton quantifications. Phantom corrections were able to recover most of these losses, but the SBRs remained significantly lower than the “true” values (p < 0.001). Calibration provided, in fact, “first order” camera-dependent corrections, but could not include “second order” subject-dependent effects, such as septal penetration from extra-cranial activity. As for the ACSC databases, phantom calibration was instrumental in compensating for partial volume losses in BRASS (~67%, p < 0.001), while for the Southampton method, inherently free from them, it brought no significant changes and solely corrected for residual inter-camera variability (−0.2%, p = 0.44). Conclusions The ENC-DAT reference values are significantly dependent on the reconstruction and quantification methods and phantom calibration, while reducing the major part of their differences, is unable to fully harmonize them. Clinical use of any normal database, therefore, requires consistency with the processing methodology. Caution must be exercised when comparing data from different centres, recognising that the SBR may represent an “index” rather than a “true” value.
Collapse
Affiliation(s)
- Livia Tossici-Bolt
- Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
| | - John C Dickson
- Institute of Nuclear Medicine, University College London Hospital NHS Foundation Trust, London, UK
| | - Terez Sera
- Department of Nuclear Medicine and Euromedic Szeged, University of Szeged, Szeged, Hungary
| | - Jan Booij
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Maria C Bagnara
- Medical Physics Unit, Az. Ospedaliera Universitaria San Martino, Genoa, Italy
| | - Thierry Vander Borght
- Nuclear Medicine Division, Mont-Godinne Medical Center, Université Catholique de Louvain, Yvoir, Belgium
| | - Cathrine Jonsson
- Department of Nuclear Medicine, Medical Physics, Karolinska University Hospital, Stockholm, Sweden
| | - Robin de Nijs
- Neurobiology Research Unit and Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Swen Hesse
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - Pierre M Koulibaly
- Nuclear Medicine Department, Centre Antoine Lacassagne, University of Nice-Sophia Antipolis, Nice, France
| | - Umit O Akdemir
- Department of Nuclear Medicine, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Michel Koole
- Nuclear Medicine, University Hospital and K.U. Leuven, Leuven, Belgium
| | - Klaus Tatsch
- Department of Nuclear Medicine, Municipal Hospital of Karlsruhe Inc., Karlsruhe, Germany
| | - Andrea Varrone
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
10
|
Klausen TL, Mortensen J, de Nijs R, Andersen FL, Højgaard L, Beyer T, Holm S. Intravenous contrast-enhanced CT can be used for CT-based attenuation correction in clinical (111)In-octreotide SPECT/CT. EJNMMI Phys 2015; 2:3. [PMID: 26501805 PMCID: PMC4545801 DOI: 10.1186/s40658-015-0108-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/14/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND CT-based attenuation correction (CT-AC) using contrast-enhancement CT impacts (111)In-SPECT image quality and quantification. In this study we assessed and evaluated the effect. METHODS A phantom (5.15 L) was filled with an aqueous solution of In-111. Three SPECT/CT scans were performed: (A) no IV contrast, (B) with 100-mL IV contrast, and (C) with 200-mL IV contrast added. Scan protocol included a localization CT, a low-dose CT (LD), and a full-dose CT (FD). Phantom, LD and FD scan series were performed at 90, 120, and 140 kVp. Phantom data were evaluated looking at mean counts in a central volume. Ten patients referred for (111)In-octreotide scintigraphy were scanned according to our clinical (111)In-SPECT/CT protocol including a topogram, a LD (140 kVp), and a FD (120 kVp). The FD/contrast-enhanced CT was acquired in both arterial (FDAP) and venous phase (FDVP) following a mono-phasic IV injection of 125-mL Optiray (4.5 mL/s). For patient data, we report image quality, Krenning scores, and mean/max values for liver and tumor regions. RESULTS Phantoms: in uncorrected emission data, mean counts (average ± SD) decreased with increasing IV concentration: (A) 119 ± 9, (B) 113 ± 8, and (C) 110 ± 9. For all attenuation correction (AC) scans, the mean values increased with increasing iodine concentration. PATIENTS there were no visible artifacts in single photon emission computed tomography (SPECT) following CT-AC with contrast-enhanced CT. The average score of image quality was 4.1 ± 0.3, 3.8 ± 0.4, and 4.2 ± 0.4 for LD, arterial phase, and venous phase, respectively. A total of 16 lesions were detected. The Krenning scores of 13/16 lesions were identical across all scan series. The max pixel values for the 16 lesions showed generally lower values for LD than for contrast-enhanced CT. CONCLUSIONS In (111)In-SPECT/CT imaging of phantoms and patients, the use of IV CT contrast did neither degrade the SPECT image quality nor affect the clinical Krenning score. Reconstructed counts in healthy liver tissues were unaffected, and there was a generally lower count value in lesions following CT-AC based on the LD non-enhanced images. Overall, for clinical interpretation, no separate low-dose CT is required for CT-AC in (111)In-SPECT/CT.
Collapse
Affiliation(s)
- Thomas Levin Klausen
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
| | - Jann Mortensen
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
| | - Robin de Nijs
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
| | - Flemming Littrup Andersen
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
| | - Liselotte Højgaard
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
| | - Thomas Beyer
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark. .,Center for Medical Physics and Biomedical Engineering, General Hospital Vienna, Medical University of Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria.
| | - Søren Holm
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
| |
Collapse
|
11
|
de Nijs R, Jensen BN, Mortensen J. Missing head and color banding in low-count SPECT reconstructions. EJNMMI Phys 2015; 1:10. [PMID: 26501452 PMCID: PMC6890917 DOI: 10.1186/2197-7364-1-10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 07/25/2014] [Indexed: 11/10/2022] Open
Abstract
Due to low counts in an 111In single photon emission computed tomography (SPECT) scan, a large part of the head was missing in the reconstructed images on Philips Extended Brilliance Workspace (EBW) and IntelliSpace Portal (ISP) workstations. This problem occurred for the ordered subsets expectation maximization (OSEM) algorithm with and without resolution recovery (Astonish), but not for filtered backprojection (FBP) or maximum likelihood expectation maximization (MLEM). There were also underflow problems because the images are stored as integers resulting in a loss of intensity resolution and color banding. Philips EBW2.0 and ISP5.02 workstations upscale low-count images, but the result is not always optimal, for example, in the case of low counts in one part and more counts in another part of an image. On these workstations, the missing head artefact problem could be resolved by applying a Hann pre-filter (with a cutoff at the Nyquist frequency, which only influences the filtering) in the reconstruction process. Upscaling of the projection data prior to reconstruction did not recover the head in the images, neither did limiting the reconstructed volume to the low-count part of interest. Underflow problems were partially solved by the new version 2.0 of the Philips EBW and ISP stations, although situations could arise where underflow still poses a problem. A solution for the underflow problems is to upscale the raw projection data before reconstruction. While this results in a pure upscaling of the FBP reconstruction, the effect in iterative statistical reconstruction is not only upscaling of the intensities because the assumption of Poisson statistics of the data is violated. However, the influence of this last matter seems limited. Reconstruction of studies with low counts in relevant areas should be performed with care. Reconstruction artefacts and scaling issues can easily arise.
Collapse
Affiliation(s)
- Robin de Nijs
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Section 4.01.2, Blegdamsvej 9, Copenhagen, 2100, Denmark.
| | - Björn Neumann Jensen
- IMT/Biomedical Unit - Section for Image Diagnostics, Rigshospitalet, Copenhagen University Hospital, Section 4.12.2, Blegdamsvej 9, Copenhagen, 2100, Denmark.
| | - Jann Mortensen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Section 4.01.2, Blegdamsvej 9, Copenhagen, 2100, Denmark. .,Faculty of Health and Medical Sciences, Copenhagen University, Blegdamsvej 3B, Copenhagen, 2200, Denmark.
| |
Collapse
|
12
|
Abstract
In order to be able to calculate half-count images from already acquired data, White and Lawson published their method based on Poisson resampling. They verified their method experimentally by measurements with a Co-57 flood source. In this comment their results are reproduced and confirmed by a direct numerical simulation in Matlab. Not only Poisson resampling, but also two direct redrawing methods were investigated. Redrawing methods were based on a Poisson and a Gaussian distribution. Mean, standard deviation, skewness and excess kurtosis half-count/full-count ratios were determined for all methods, and compared to the theoretical values for a Poisson distribution. Statistical parameters showed the same behavior as in the original note and showed the superiority of the Poisson resampling method. Rounding off before saving of the half count image had a severe impact on counting statistics for counts below 100. Only Poisson resampling was not affected by this, while Gaussian redrawing was less affected by it than Poisson redrawing. Poisson resampling is the method of choice, when simulating half-count (or less) images from full-count images. It simulates correctly the statistical properties, also in the case of rounding off of the images.
Collapse
Affiliation(s)
- Robin de Nijs
- Copenhagen University Hospital, Rigshospitalet, Department of Clinical Physiology, Nuclear Medicine and PET, Blegdamsvej 9 2100 Copenhagen, Denmark
| |
Collapse
|
13
|
Jensen P, Feng L, Law I, Svarer C, Knudsen GM, Mikkelsen JD, de Nijs R, Larsen VA, Dyssegaard A, Thomsen G, Fischer W, Guilloteau D, Pinborg LH. TSPO Imaging in Glioblastoma Multiforme: A Direct Comparison Between 123I-CLINDE SPECT, 18F-FET PET, and Gadolinium-Enhanced MR Imaging. J Nucl Med 2015; 56:1386-90. [PMID: 26182972 DOI: 10.2967/jnumed.115.158998] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/06/2015] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Here we compare translocator protein (TSPO) imaging using 6-chloro-2-(4'-(123)I-iodophenyl)-3-(N,N-diethyl)-imidazo[1,2-a]pyridine-3-acetamide SPECT ((123)I-CLINDE) and amino acid transport imaging using O-(2-(18)F-fluoroethyl)-l-tyrosine PET ((18)F-FET) and investigate whether (123)I-CLINDE is superior to (18)F-FET in predicting progression of glioblastoma multiforme (GBM) at follow-up. METHODS Three patients with World Health Organization grade IV GBM were scanned with (123)I-CLINDE SPECT, (18)F-FET PET, and gadolinium-enhanced MR imaging. Molecular imaging data were compared with follow-up gadolinium-enhanced MR images or contrast-enhanced CT scans. RESULTS The percentage overlap between volumes of interest (VOIs) of increased (18)F-FET uptake and (123)I-CLINDE binding was variable (12%-42%). The percentage overlap of MR imaging baseline VOIs was greater for (18)F-FET (79%-93%) than (123)I-CLINDE (15%-30%). In contrast, VOIs of increased contrast enhancement at follow-up compared with baseline overlapped to a greater extent with baseline (123)I-CLINDE VOIs than (18)F-FET VOIs (21% vs. 8% and 72% vs. 55%). CONCLUSION Our preliminary results suggest that TSPO brain imaging in GBM may be a useful tool for predicting tumor progression at follow-up and may be less susceptible to changes in blood-brain barrier permeability than (18)F-FET. Larger studies are warranted to test the clinical potential of TSPO imaging in GBM, including presurgical planning and radiotherapy.
Collapse
Affiliation(s)
- Per Jensen
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Ling Feng
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Ian Law
- Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | | | - Robin de Nijs
- Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, Copenhagen, Denmark
| | - Vibeke A Larsen
- Department of Radiology, Rigshospitalet, Copenhagen, Denmark
| | | | - Gerda Thomsen
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Walter Fischer
- Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark
| | - Denis Guilloteau
- Université François-Rabelais de Tours, INSERM U930 "Imaging and Brain," Tours, France; and
| | - Lars H Pinborg
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark Epilepsy Clinic, Department of Neurology, Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
14
|
Feng L, Svarer C, Thomsen G, de Nijs R, Larsen VA, Jensen P, Adamsen D, Dyssegaard A, Fischer W, Meden P, Krieger D, Møller K, Knudsen GM, Pinborg LH. In Vivo Quantification of Cerebral Translocator Protein Binding in Humans Using 6-Chloro-2-(4′-123I-Iodophenyl)-3-(N,N-Diethyl)-Imidazo[1,2-a]Pyridine-3-Acetamide SPECT. J Nucl Med 2014; 55:1966-72. [DOI: 10.2967/jnumed.114.143727] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
|
15
|
Balyasnikova S, Löfgren J, de Nijs R, Zamogilnaya Y, Højgaard L, Fischer BM. PET/MR in oncology: an introduction with focus on MR and future perspectives for hybrid imaging. Am J Nucl Med Mol Imaging 2012; 2:458-474. [PMID: 23145362 PMCID: PMC3484424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/21/2012] [Indexed: 06/01/2023]
Abstract
After more than 20 years of research, a fully integrated PET/MR scanner was launched in 2010 enabling simultaneous acquisition of PET and MR imaging. Currently, no clinical indication for combined PET/MR has been established, however the expectations are high. In this paper we will discuss some of the challenges inherent in this new technology, but focus on potential applications for simultaneous PET/MR in the field of oncology. Methods and tracers for use with the PET technology will be familiar to most readers of this journal; thus this paper aims to provide a short and basic introduction to a number of different MRI techniques, such as DWI-MR (diffusion weighted imaging MR), DCE-MR (dynamic contrast enhanced MR), MRS (MR spectroscopy) and MR for attenuation correction of PET. All MR techniques presented in this paper have shown promising results in the treatment of patients with solid tumors and could be applied together with PET increasing the amount of information about the tissues of interest. The potential clinical benefit of applying PET/MR in staging, radiotherapy planning and treatment evaluation in oncology, as well as the research perspectives for the use of PET/MR in the development of new tracers and drugs will be discussed.
Collapse
Affiliation(s)
- Svetlana Balyasnikova
- Department of Radiology, The N. N. Blokhin Cancer Research Center, Russian Academy of Medical Sciences 24, Kashirskoe Shosse, Moscow, 115478, Russia
| | | | | | | | | | | |
Collapse
|
16
|
Jensen PS, Ziebell M, Skouboe G, Khalid U, de Nijs R, Thomsen G, Knudsen GM, Svarer C. Validation of a method for accurate and highly reproducible quantification of brain dopamine transporter SPECT studies. J Nucl Med Technol 2011; 39:271-8. [PMID: 22072699 DOI: 10.2967/jnmt.111.090324] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED In nuclear medicine brain imaging, it is important to delineate regions of interest (ROIs) so that the outcome is both accurate and reproducible. The purpose of this study was to validate a new time-saving algorithm (DATquan) for accurate and reproducible quantification of the striatal dopamine transporter (DAT) with appropriate radioligands and SPECT and without the need for structural brain scanning. METHODS In a reconstructed DAT SPECT image, DATquan automatically calculated the ratio at steady state of specifically bound radioligand to nondisplaceable radioligand in tissue (BP(ND)) within striatal ROIs that were delineated by use of a semiautomatic template-based alignment approach. DATquan was tested with (123)I-N-(3-iodoprop-2E-enyl)-2-β-carbomethoxy-3β-(4-methylphenyl) SPECT images from 15 patients. In each image, ROIs were first manually delineated, and then corresponding BP(ND) values were derived by an experienced physician. Afterward, 2 independent novice operators used DATquan to analyze the same 15 images. The resulting DATquan-derived BP(ND) data were compared with the data retrieved by manual delineation to assess the accuracy and reproducibility of DATquan. Also, the operational aspects of DATquan were assessed on the basis of measurements of the mean running time of the algorithm as well as on the basis of quantification of the overlap of the DATquan-delineated ROIs obtained by the 2 operators. RESULTS The mean algorithm running time was 3 min, and the operators' striatal ROIs had a mean overlap of more than 82%. DATquan-derived BP(ND) values obtained by the 2 operators showed high agreement (the mean difference was 0.00 [SD, 0.05] in the striatum, 0.02 [SD, 0.26] in the putamen, and 0.03 [SD, 0.43] in the caudate nucleus). The interoperator variability was 2.2% (SD, 1.3%) in the striatum, 11.7% (SD, 9.9%) in the putamen, and 12.9% (SD, 4.0%) in the caudate nucleus. DATquan-derived BP(ND) values showed high agreement with the values manually derived by the experienced delineator. CONCLUSION DATquan is a freely available, accurate, and highly reproducible method for quantification of DAT binding in the brain by SPECT. Once implemented in clinics, DATquan will serve as a useful and time-saving tool.
Collapse
Affiliation(s)
- Peter S Jensen
- Neurobiology Research Unit, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | | | | | | | | | | | | | | |
Collapse
|
17
|
de Nijs R, Holm S, Thomsen G, Ziebell M, Svarer C. Experimental determination of the weighting factor for the energy window subtraction-based downscatter correction for I-123 in brain SPECT studies. J Med Phys 2011; 35:215-22. [PMID: 21170186 PMCID: PMC2990116 DOI: 10.4103/0971-6203.71765] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 04/15/2010] [Accepted: 04/19/2010] [Indexed: 11/12/2022] Open
Abstract
Correction for downscatter in I-123 SPECT can be performed by the subtraction of a secondary energy window from the main window, as in the triple-energy window method. This is potentially noise sensitive. For studies with limited amount of counts (e.g. dynamic studies), a broad subtraction window with identical width is preferred. This secondary window needs to be weighted with a factor higher than one, due to a broad backscatter peak from high-energy photons appearing at 172 keV. Spatial dependency and the numerical value of this weighting factor and the image contrast improvement of this correction were investigated in this study. Energy windows with a width of 32 keV were centered at 159 keV and 200 keV. The weighting factor was measured both with an I-123 point source and in a dopamine transporter brain SPECT study in 10 human subjects (5 healthy subjects and 5 patients) by minimizing the background outside the head. Weighting factors ranged from 1.11 to 1.13 for the point source and from 1.16 to 1.18 for human subjects. Point source measurements revealed no position dependence. After correction, the measured specific binding ratio (image contrast) increased significantly for healthy subjects, typically by more than 20%, while the background counts outside of all subjects were effectively removed. A weighting factor of 1.1–1.2 can be applied in clinical practice. This correction effectively removes downscatter and significantly improves image contrast inside the brain.
Collapse
Affiliation(s)
- Robin de Nijs
- Department of Clinical Physiology, Nuclear Medicine, PET and Cyclotron Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | | | | | | | | |
Collapse
|
18
|
de Nijs R, Miranda MJ, Hansen LK, Hanson LG. Motion correction of single-voxel spectroscopy by independent component analysis applied to spectra from nonanesthetized pediatric subjects. Magn Reson Med 2009; 62:1147-54. [DOI: 10.1002/mrm.22129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
19
|
Frokjaer VG, Pinborg LH, Madsen J, de Nijs R, Svarer C, Wagner A, Knudsen GM. Evaluation of the Serotonin Transporter Ligand 123I-ADAM for SPECT Studies on Humans. J Nucl Med 2008; 49:247-54. [PMID: 18199621 DOI: 10.2967/jnumed.107.046102] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Imaging serotonin transporters in the living human brain is important in several fields, such as normal psychophysiology, mood disorders, eating disorders, and neurodegenerative disorders. The aim of this study was to compare different kinetic and semiquantitative methods for assessing serotonin transporters using (123)I-labeled 2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine (ADAM) in humans: an arterial plasma input model, simplified and Logan reference tissue models, and standardized uptake value ratios. METHODS Nine subjects were scanned with dynamic (123)I-ADAM SPECT (mean age, 31 y; range, 24-43 y), and metabolite-corrected arterial input was measured. Tissue reference models (simplified reference tissue model, Logan reference tissue model, and ratio method) were validated against the outcome of a 1-tissue-compartment model, and performance with decreasing scan length was evaluated. The specificity of (123)I-ADAM binding was investigated in a blocking experiment. RESULTS Binding estimates from the simplified reference tissue and Logan reference tissue models correlated tightly with full kinetic modeling when based on a 240- or 360-min dynamic acquisition (r = 0.99); however, there were slight underestimations (3%-5%), especially in high-binding regions. Application of the ratio method to data from 200 to 240 min overestimated specific binding (on average, by 10% +/- 28%) and correlated only moderately with estimates from the 1-tissue-compartment model (r = 0.94). With an acquisition time of 0-120 min, the Logan model still yielded an acceptable outcome when a fixed clearance rate constant (k2') from the cerebellum was applied. Intravenously injected citalopram was not associated with a decrease in cerebellar binding. A lipophilic metabolite that did not seem to bind specifically to serotonin transporter was seen in 2 of 7 subjects. CONCLUSION Serotonin transporter binding with (123)I-ADAM SPECT can be assessed with the Logan model based on a 120-min acquisition when a constant k2' is applied. This model, because it allows for more accurate and less biased binding estimates and thus reduces the required sample size, is advantageous over the ratio method used in clinical studies so far. A single blocking experiment supported the use of the cerebellum as a reference region.
Collapse
Affiliation(s)
- Vibe G Frokjaer
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
| | | | | | | | | | | | | |
Collapse
|
20
|
Ziebell M, Thomsen G, Knudsen GM, de Nijs R, Svarer C, Wagner A, Pinborg LH. Reproducibility of [123I]PE2I binding to dopamine transporters with SPECT. Eur J Nucl Med Mol Imaging 2006; 34:101-9. [PMID: 16896668 DOI: 10.1007/s00259-006-0161-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 04/11/2006] [Accepted: 04/30/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE The iodinated cocaine derivative [(123)I]PE2I is a new selective ligand for in vivo studies of the dopamine transporter (DAT) with SPECT. Recently, a bolus/infusion (B/I) protocol for [(123)I]PE2I measurements of DAT density was established [Pinborg LH et al. J Nucl Med 2005;46:1119-271]. The aims of this study were, firstly, to evaluate the test-retest variability using the B/I protocol and, secondly, to evaluate the B/I approach in a new group of healthy subjects using two outcome parameters, BP(1) (C(ROI)/C(plasma)) and BP(2) (C(ROI)/C(REF)). METHODS Seven healthy subjects were subjected to [(123)I]PE2I SPECT scanning twice. For both studies, the two outcome parameters BP(1) and BP(2) were calculated based on two different methods for region of interest (ROI) delineation, namely manual delineation and probability map-based automatic delineation with MRI co-registration. RESULTS With manual delineation, striatal test-retest variability (absolute difference between first and second scan as a percentage of the mean) of BP(1) and BP(2) was 13.9% (range 1.8-35.7%) and 4.1% (range 0.5-9.7%) respectively. The probability map-based automatic delineation resulted in striatal test-retest variability of 17.2% (range 4.3-40.5%) and 5.2% (range 0.1-10.9%) respectively. The B/I approach provided stable brain activity from 120 to 180 min post injection in both high- and low-count regions with a mean % change/hour in striatal BP(2) of 10.6. CONCLUSION [(123)I]PE2I SPECT with the B/I approach yields a highly reproducible measure of striatal dopamine transporter binding. The appropriateness of a B/I protocol with a B/I ratio of 2.7 h (i.e. with a bolus worth 2.7 h of infusion) was confirmed in an independent sample of healthy subjects.
Collapse
Affiliation(s)
- Morten Ziebell
- Neurobiology Research Unit, Rigshospitalet, N9201, 9 Blegdamsvej, Copenhagen, 2100, Denmark.
| | | | | | | | | | | | | |
Collapse
|
21
|
Pinborg LH, Ziebell M, Frøkjaer VG, de Nijs R, Svarer C, Haugbøl S, Yndgaard S, Knudsen GM. Quantification of 123I-PE2I binding to dopamine transporter with SPECT after bolus and bolus/infusion. J Nucl Med 2005; 46:1119-27. [PMID: 16000280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
UNLABELLED The aim of the present study was to describe a method combining easy implementation in a clinical setting with accuracy and precision in quantification of 123I-labeled N-(3-iodoprop-(2E)-enyl)-2beta-carboxymethoxy-3beta-(4'-methylphenyl)nortropane (PE2I) binding to brain dopamine transporter. METHODS Five healthy subjects (mean age, 50 y; range, 40-68 y) were studied twice. In the first experiment, dynamic SPECT data and arterial plasma input curves obtained after 123I-PE2I bolus injection were assessed using Logan, kinetic, transient equilibrium, and peak equilibrium analyses. Accurate and precise determination of BP1 (binding potential times the free fraction in the metabolite-corrected plasma compartment) and BP2 (binding potential times the free fraction in the intracerebral nonspecifically bound compartment) was achieved using Logan analysis and kinetic analysis, with a total study time of 90 min. In the second experiment, (123)I-PE2I was administrated as a combined bolus and constant infusion. The bolus was equivalent to 2.7 h of constant infusion. RESULTS The bolus-to-infusion ratio of 2.7 h was based on the average terminal clearance rate from plasma in the bolus experiments. Steady state was attained in brain and plasma within 2 h, and time-activity curves remained constant for another 2 h. Even when an average bolus-to-infusion ratio was used, the striatal BP1 and BP2 values calculated with kinetic analysis (BP1 = 21.1 +/- 1.1; BP2 = 4.1 +/- 0.4) did not significantly differ from those calculated with bolus/infusion analysis (BP1 = 21.0 +/- 1.2; BP2 = 4.3 +/- 0.3). Computer simulations confirmed that a 2-fold difference in terminal clearance rate from plasma translates into only a 10% difference in BP1 and BP2 calculated from 120 to 180 min after tracer administration. CONCLUSION The bolus/infusion approach allows accurate and precise quantification of 123I-PE2I binding to dopamine transporter and is easily implemented in a clinical setting.
Collapse
Affiliation(s)
- Lars H Pinborg
- Neurobiology Research Unit, University Hospital Rigshospitalet, Copenhagen, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|