Iterative reconstruction or filtered backprojection for semi-quantitative assessment of dopamine D2 receptor SPECT studies?
- 200 Downloads
In routine clinical practice striatal dopamine D2 receptor binding is generally assessed using data reconstructed by filtered backprojection (FBP). The aim of this study was to investigate the use of an iterative reconstruction algorithm (ordered subset expectation maximization, OSEM) and to assess whether it may provide comparable or even better results than those obtained by standard FBP.
In 56 patients with parkinsonian syndromes, single photon emission computed tomography (SPECT) scans were acquired 2 h after i.v. application of 185 MBq [123I]iodobenzamide (IBZM) using a triple-head gamma camera (Siemens MS 3). The scans were reconstructed both by FBP and OSEM (3 iterations, 8 subsets) and filtered using a Butterworth filter. After attenuation correction the studies were automatically fitted to a mean template with a corresponding 3-D volume of interest (VOI) map covering striatum (S), caudate (C), putamen (P) and several reference VOIs using BRASS software.
Visual assessment of the fitted studies suggests a better separation between C and P in studies reconstructed by OSEM than FBP. Unspecific background activity appears more homogeneous after iterative reconstruction. The correlation shows a good accordance of dopamine receptor binding using FBP and OSEM (intra-class correlation coefficients S: 0.87; C: 0.88; P: 0.84). Receiver-operating characteristic (ROC) analyses show comparable diagnostic power of OSEM and FBP in the differentiation between idiopathic parkinsonian syndrome (IPS) and non-IPS.
Iterative reconstruction of IBZM SPECT studies for assessment of the D2 receptors is feasible in routine clinical practice. Close correlations between FBP and OSEM data suggest that iteratively reconstructed IBZM studies allow reliable quantification of dopamine receptor binding even though a gain in diagnostic power could not be demonstrated.
KeywordsIterative reconstruction IBZM Automatic data processing Dopamine D2 receptors
Conflicts of interest
- 10.Catafau AM, Bullich S, Danús M, Penengo MM, Cot A, Abanades S, et al. Test-retest variability and reliability of 123I-IBZM SPECT measurement of striatal dopamine D2 receptor availability in healthy volunteers and influence of iterative reconstruction algorithms. Synapse 2008;62:62–9.PubMedCrossRefGoogle Scholar
- 12.Tatsch K, Asenbaum S, Bartenstein P, Catafau A, Halldin C, Pilowsky LS, et al. European Association of Nuclear Medicine procedure guidelines for brain neurotransmission SPET using (123)I-labelled dopamine D(2) transporter ligands. Eur J Nucl Med Mol Imaging 2002;29:BP30–5.PubMedCrossRefGoogle Scholar
- 29.Van Laere KJ, Warwick J, Versijpt J, Goethals I, Audenaert K, Van Heerden B, et al. Analysis of clinical brain SPECT data based on anatomic standardization and reference to normal data: an ROC-based comparison of visual, semiquantitative, and voxel-based methods. J Nucl Med 2002;43:458–69.PubMedGoogle Scholar