RT Journal Article
SR Electronic
T1 MRI-Guided Region-of-Interest Delineation Is Comparable to Manual Delineation in Dopamine Transporter SPECT Quantification in Patients: A Reproducibility Study
JF Journal of Nuclear Medicine Technology
JO J. Nucl. Med. Technol.
FD Society of Nuclear Medicine
SP 61
OP 68
DO 10.2967/jnmt.109.072801
VO 38
IS 2
A1 Ziebell, Morten
A1 Pinborg, Lars H.
A1 Thomsen, Gerda
A1 de Nijs, Robin
A1 Svarer, Claus
A1 Wagner, Aase
A1 Knudsen, Gitte M.
YR 2010
UL http://tech.snmjournals.org/content/38/2/61.abstract
AB A particularly sensitive step in the quantification of SPECT images of the dopamine transporter (DAT) is a correct delineation of the region of interest (ROI). In this study, we primarily compared the reproducibility of the following different approaches for ROI delineation in SPECT images of the DAT: the use of manual delineation (MD) on high-count striatal slides directly on the SPECT image, ROI delineation based on individual MR images (MRD), and oversized striatal ROIs—that is, the striatal volume of interest (SVI), as described previously. We also assessed the ability of the different approaches to identify striatal pathology in patients with parkinsonism. Methods: Eight patients with highly variable reductions in cerebral DAT availability were SPECT-scanned twice with 123I-labeled N-(3-iodoprop-(2E)-enyl)-2β-carboxymethoxy-3β-(4′-methylphenyl) nortropane bolus infusion setup and once with an MRI scanner. For SPECT/MRI coregistration, we used external fiducial markers visible on both MRI and SPECT. With the MD and MRD methods, the outcome parameters for DAT availability were the binding potentials and the ratio at equilibrium of specifically bound radioligand to nondisplaceable radioligand in tissue (BPND). For the SVI method, the outcome parameter was the specific binding ratio (SBR). Results: No statistically significant difference in striatal BPND intraobserver reproducibility was seen among any of the 3 methods. The intraobserver reproducibility average ± SD for MD was 7.0% ± 4.1%; for MRD, 5.7% ± 5.4%; and for SVI, 6.7% ± 6.0%. Mean intrasubject variability, as determined from the test–retest scans, did not differ with the 3 delineation methods used. The average (±SD) intrasubject variability of striatal BPND was 11.9% ± 10.0% with MD and 14.6% ± 15.3% with MRD. With the SVI method, the intrasubject variability of striatal specific binding ratio was 10.0% ± 10.2%. BPND values obtained with the MD and MRD methods were similar (paired t test, P > 0.4). Conclusion: In patients with reduced striatal DAT binding, the reproducibility of the outcome from ROI MD is comparable to both that obtained by delineation of ROI on individual MR images, followed by coregistration to the SPECT image, and that obtained with the SVI-based approach.