Transfer of normal 99mTc-ECD brain SPET databases between different gamma cameras

Abstract

A stereotactic, normal perfusion database is imperative for optimal clinical brain single-photon emission tomography (SPET). However, interdepartmental use of normal data necessitates accurate transferability of these data sets. The aim of this study was to investigate transfer of three normal perfusion databases obtained in the same large population of healthy volunteers who underwent sequential scanning using multihead gamma cameras with different resolution. Eighty-nine healthy adults (46 females, 43 males; aged 20-81 years) were thoroughly screened by history, biochemistry, physical and full neurological examination, neuropsychological testing and magnetic resonance imaging. After injection of 925 MBq technetium-99m labelled ethyl cysteinate dimer (ECD) under standard conditions, 101 scans were acquired from all subjects (12 repeat studies) on a triple-head Toshiba GCA-9300A (measured average FWHM 8.1 mm). Ninety-one sequential scans were performed on a dual-head Elscint Helix camera (FWHM 9.6 mm) and 22 subjects also underwent imaging on a triple-head Prism 3000 (FWHM 9.6 mm). Images were transferred to the same processing platform and reconstructed by filtered back-projection with the same Butterworth filter (order 8, cut-off 0.9 cycles/cm) and uniform Sorensen attenuation correction (mu = 0.09). After automated rigid intrasubject registration, all subjects were automatically reoriented to a stereotactic template by a nine-parameter affine transformation. The databases were analysed using 35 predefined volumes of interest (VOIs) with normalisation on total VOI counts. For comparison, the high-resolution data were smoothed with a 3D Gaussian kernel to achieve more similar spatial resolution. Hoffman phantom measurements were conducted on all cameras. Partial volume effects after smoothing varied between -6.5% and 10%, depending on VOI size. Between-camera reproducibility was 2.5% and 2.7% for the Toshiba camera versus the Helix and the Prism database, respectively. The highest reduction in between-camera variability was achieved by resolution adjustment in combination with linear washout correction and a Hoffman phantom-based correction. In conclusion, transfer of normal perfusion data between multihead gamma cameras can be accurately achieved, thereby enabling widespread interdepartmental use, which is likely to have a positive impact on the diagnostic capabilities of clinical brain perfusion SPET.

Stereotactic statistical imaging analysis of the brain using the easy Z-score imaging system for sharing a normal database

“…[14][15][16] There is no report of such a method being actually applied in clinical practice. Because SPECT systems differ in spatial resolution, signal-to-noise (S/N) ratio, and uniformity, the sensitivity to lesions differs.…”

Quantitative Analysis in Functional Brain Imaging

“…The highest reduction in between-camera variability was achieved by resolution adjustment in combination with a 3D Hoffman brain phantom-based correction. 133 The difficulties in the inverse transfer of absolute metabolic PET data from lower to higher resolution was reported by Grady et al as early as in 1989, with data in 9 subjects of relatively low resolution, different attenuation and operator dependent ROIs. 134 Intrinsically, the same inference could be made for receptor studies, although the actual outcome measures (e.g.…”

Evaluation of a novel normal database with matched SPECT systems and optimal pre-filter parameters for 3D-SSP

“…Therefore, devices prepared at other institutions have depended on our conventional NDB (comprising six types of four models). When using NDBs from other institutions, image quality considerably differs among devices, and actual outcomes are influenced [8][9][10].…”