Abstract
PurposeAttenuation correction (AC) based on low-dose computed tomography (CT) could be more accurate in brain single-photon emission computed tomography (SPECT) than the widely used Chang method, and, therefore, has the potential to improve both semi-quantitative analysis and visual image interpretation. The present study evaluated CT-based AC for dopamine transporter SPECT with I-123-ioflupane.Materials and methodsSixty-two consecutive patients in whom I-123-ioflupane SPECT including low-dose CT had been performed were recruited retrospectively at 3 centres. For each patient, 3 different SPECT images were reconstructed: without AC, with Chang AC and with CT-based AC. Distribution volume ratio (DVR) images were obtained by scaling voxel intensities using the whole brain without striata as reference. For assessing the impact of AC on semi-quantitative analysis, specific-to-background ratios (SBR) in caudate and putamen were obtained by fully automated SPM8-based region of interest (ROI) analysis and tested for their diagnostic power using receiver-operator-characteristic (ROC) analysis. For assessing the impact of AC on visual image reading, screenshots of stereotactically normalized DVR images presented in randomized order were interpreted independently by two raters at each centre.ResultsCT-based AC resulted in intermediate SBRs about half way between no AC and Chang. Maximum area under the ROC curve was achieved by the putamen SBR, with negligible impact of AC (0.924, 0.935 and 0.938 for no, CT-based and Chang AC). Diagnostic accuracy of visual interpretation also did not depend on AC.ConclusionsThe impact of CT-based versus Chang AC on the interpretation of I-123-ioflupane SPECT is negligible. Therefore, CT-based AC cannot be recommended for routine use in clinical patient care, not least because of the additional radiation exposure.
Highlights
Single photon emission computed tomography (SPECT) with I123-labelled cocaine ligands for the presynaptic dopamine transporter (DAT) is widely used for the diagnosis of Parkinsonian syndromes and for differentiation between Alzheimer’s and Lewy body disease [1,2,3,4,5,6,7,8]
Maximum area under the ROC curve was achieved by the putamen specific-to-background ratios (SBR), with negligible impact of attenuation correction (AC) (0.924, 0.935 and 0.938 for no, CT-based and Chang AC)
The putamen SBR was included in the multiple regression analysis, since there was a strong correlation between caudate and putamen SBR (Pearson correlation coefficient = 0.87, p = 0.000, Chang AC) so that it was not advisable to include both as independent parameters
Summary
Single photon emission computed tomography (SPECT) with I123-labelled cocaine ligands for the presynaptic dopamine transporter (DAT) is widely used for the diagnosis of Parkinsonian syndromes and for differentiation between Alzheimer’s and Lewy body disease [1,2,3,4,5,6,7,8]. It is used for monitoring progression of presynaptic dopaminergic degeneration [9]. It is strictly correct only for a point source (at least in its non-iterative form)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
