Evaluating image-derived input functions for cerebral [18F]MC225 PET studies

Frontiers in Nuclear Medicine, vol. 5, pp. 1597902

Abstract

Kinetic modelling of brain PET data is crucial for estimating quantitative biological parameters, traditionally requiring arterial sampling. This study evaluated whether arterial samples could be omitted to estimate the image-derived input function (IDIF) using a long axial field-of-view PET scanner. The use of internal carotid arteries (ICA) for IDIF estimation, along with venous samples for plasma-to-whole blood ratios and plasma parent fractions, was also assessed. Six healthy volunteers underwent [18F]MC225 scans with manual arterial sampling. IDIFs were derived from the aortic arch (IDIFAA) and calibrated using manual arterial samples (IDIFAA_CAL). ICA-derived IDIF was also calibrated (IDIFCA_CAL) and compared to IDIFAA_CAL. In a separate group of six volunteers, venous and arterial samples were collected to evaluate plasma-to-whole blood ratios, plasma parent fractions, and IDIF calibration (IDIFCA_CAL_VEN). Volume of distribution (VT) of different brain regions was estimated for all IDIFs techniques, corrected for plasma-to-whole blood ratio and plasma parent fraction (IDIFAA,P, IDIFAA_CAL,P, IDIFICA_CAL,P and IDIFICA_CAL_VEN_P). Our findings revealed discrepancies between IDIFAA and arterial samples, highlighting the importance of calibration. The differences between IDIFAA,P and IDIFAA_CAL,P were 9.2% for area under the curve and 4.0% for brain VT. IDIFICA_CAL,P showed strong agreement with IDIFA_CAL,P, with 1.2% VT difference. Venous sampling showed consistent agreement with arterial sampling for plasma parameters but was unreliable for IDIF calibration, leading to 39% VT differences. This study emphasises that arterial samples are still required for IDIF calibration and reliable VT estimation for [18F]MC225 PET tracer. ICA-derived IDIF, when calibrated, provides reliable VT estimates. Venous sampling is a potential alternative for estimating plasma parameters, but it is unsuitable for IDIF calibration. Trial Registry NCT05618119 (clinicaltrials.gov/study/NCT05618119).

Authors 11

1. Giordana Salvi de Souza

   University Medical Center Groningen · University of Groningen · Pontifícia Universidade Católica do Rio Grande do Sul

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

   School of Medicine, PUCRS, Porto Alegre, Brazil

2. Pascalle Mossel Aachen Department of Radiology, Leiden University Medical Center

   University Medical Center Groningen · University of Groningen · Leiden University Medical Center

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

   Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

3. Joost F. Somsen

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

4. Laura Providência

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

5. Anna L. Bartels

   Ommelander Ziekenhuis Groningen

   Affiliation as printed

   Department of Neurology, Ommelander Ziekenhuis Groep, Scheemda, Netherlands

6. Antoon T. M. Willemsen

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

7. Rudi Dierckx

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

8. Cristiane Regina Guerino Furini

   Instituto do Cérebro · Pontifícia Universidade Católica do Rio Grande do Sul

   Affiliation as printed

   Laboratory of Cognition and Memory Neurobiology, Brain Institute, PUCRS, Porto Alegre, Brazil

   School of Medicine, PUCRS, Porto Alegre, Brazil

9. Adriaan A. Lammertsma

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

10. Charalampos Tsoumpas

    University Medical Center Groningen · University of Groningen

    Affiliation as printed

    Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

11. Gert Luurtsema corresponding

    University Medical Center Groningen · University of Groningen

    Affiliation as printed

    Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands