Absolute SPECT/CT quantification of cerebral uptake of 99mTc-HMPAO for patients with neurocognitive disorders

• Published in: Nuclear medicine Vol. 55; no. 4; p. 158
• Main Authors: Welz, Friedrich, Sanders, James C, Kuwert, Torsten, Maler, Juan, Kornhuber, Johannes, Ritt, Philipp
• Format: Journal Article
• Language: English
• Published: Germany 05.08.2016
• Subjects: Aged; Aged, 80 and over; Brain - diagnostic imaging; Brain - metabolism; Computer Simulation; Dementia - diagnosis; Dementia - metabolism; Female; Humans; Image Interpretation, Computer-Assisted - methods; Male; Metabolic Clearance Rate; Middle Aged; Models, Neurological; Radiopharmaceuticals - pharmacokinetics; Reproducibility of Results; Sensitivity and Specificity; Single Photon Emission Computed Tomography Computed Tomography - methods; Technetium Tc 99m Exametazime - pharmacokinetics; HMPAO; brain perfusion; SPECT/CT; Absolute quantification
• ISSN: 0029-5566
• DOI: 10.3413/Nukmed-0765-15-09

It was reported from planar imaging studies that the cerebral uptake of injected 99mTc-HMPAO activity is about 4-7% in humans. Recent work has shown that modern SPECT/CT devices are able to quantify the tissue concentration of radioactivity in vivo in absolute units (Bq/ml), while avoiding the limitations of planar techniques. The aims of this study were (a) to determine the cerebral uptake of 99mTc-HMPAO in absolute units in SPECT/CT, (b) to investigate potential differences in absolute tracer uptake for patients suspected of dementia. We performed 99mTc-HMPAO SPECT/CT in 65 patients with suspected dementia. 99mTc-HMPAO uptake was determined using a previously published quantitative SPECT/CT protocol. The absolute HMPAO uptake and the results of a regionalized analysis were compared for MMSE and NINCDS-ADRDA based patient groups. The mean absolute uptake of 99mTc-HMPAO for our patient population was 4.3 ± 0.8% of the injected dose. The uptake, as well as the regionalized analysis yielded significantly different results for low (≤23) and high (>23) MMSE groups and also for some of the NINCDS-ADRDA groups. Our results show that the absolute cerebral uptake of 99mTc-HMPAO is in the range of previously reported results, obtained by planar techniques. Absolute uptake is significantly different between the patient groups.