Studies investigating the age-related impact on dopamine transporter binding have previously omitted the use of attenuation correction by computed tomography (CT). We aimed to explore the impact of age and gender on dopamine transporter binding on [123I]Ioflupane single photon emission CT (SPECT) imaging with simultaneously acquired CT.
Three hundred forty-two patients with clinically uncertain parkinsonian syndrome underwent [123I]-Ioflupane SPECT/CT with CT-based attenuation correction. Two nuclear medicine physicians independently performed a visual evaluation of all scans and only visibly normal scans were included for further analysis. Moreover, the results of a fully automatic semiquantitative evaluation method were recorded. Thereafter, the obtained [123I]Ioflupane binding ratio and the hemispheric asymmetry index were correlated with age and sex.
Patient age range was 41–80 years with a balanced distribution over decades. Of 342 patients, 133 (38.9%, 66 females, median age, 64 years) were considered visually normal by both observers on the SPECT/CT images. A significant inverse correlation between age and [123I]Ioflupane binding ratios in the striata (R = −0.38; P < 0.001), putamina (R = −0.39; P < 0.001) and caudate nuclei (R = −0.3; P < 0.001) was demonstrated. Linear regression of all included subjects demonstrated an average decrease of 0.19 per decade in the striatal binding ratio (6.6%). No significant sex differences were found in striatal binding ratios (P = 0.86). Moreover, no significant correlation was observed between age and striatal asymmetry index (r = 0.12; P = 0.16).
In the present largest single-center analysis investigating [123I]Ioflupane SPECT/CT in patients with clinical uncertain parkinsonian syndrome, a dopamine transporter loss of 6.6% per decade in visually normal scans was recorded.
aDivision of Nuclear Medicine and Molecular Imaging, The Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
bDepartment of Nuclear Medicine, Hannover Medical School, Hannover
cDepartment of Nuclear Medicine/Comprehensive Heart Failure Center, University of Wuerzburg, Wuerzburg, Germany
dOkayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
Dr. Rudolf A. Werner and Dr. Constantin Lapa contributed equally to the writing of this article.
Received 7 April 2019 Accepted 12 June 2019
Correspondence to Rudolf A. Werner, MD, Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacherst 6, 97080 Würzburg, Germany, Tel: +49 931 201 35905; fax: +49 931 201 6 555 00; e-mail: email@example.com