99m Tc-TRODAT-1 SPECT/CT imaging as a complementary biomarker in the diagnosis of parkinsonian syndromes Bhagwant R. Mittal a , Apurva Sood a , Jaya Shukla a , Rakhee Vatsa a , Priya Bhusari a , Ritu Shree b , Sahil Mehta b , Manoj Goyal b and Manish Modi b Introduction Parkinson’s disease (PD) and Parkinson plus syndromes (PPS) are neurodegenerative movement disorders caused by loss of dopamine in the basal ganglia. The diagnosis of both PD and PPS is complex as it is made solely on the basis of clinical features, with no established imaging modality to aid in the diagnosis. Technetium-99m- labeled tropane derivative ( 99m Tc-TRODAT-1) binds to the dopamine transporters present in the presynaptic membrane of the dopaminergic nerve terminal. The aim of this prospective study was to investigate the potential usefulness of 99m Tc-TRODAT-1 imaging in the diagnosis of PD and PPS. Patients and methods Fifty-eight patients with a clinical diagnosis of idiopathic PD or PPS were recruited. The severity of the disease was assessed using the Hoehn and Yahr scale. Patients in stage I and II were considered as cases of Early PD. Twenty-five apparently healthy volunteers served as controls. Brain single-photon emission computed tomography/computed tomography in all the participants was performed 3–4 h after an injection of 99m Tc-TRODAT-1. Specific uptake ratios (SURs) of striatum were calculated for both the left and right striatum, and the values were compared between PD, PPS, and healthy volunteers. Results A significant lower uptake of tracer activity was found in either of the striatum in PD and PPS cases compared with the control group, which showed a symmetrical comma-shaped striatal uptake. This was also reflected in the SUR values, which were significantly higher in the control group in comparison with the PD and PPS patients (P < 0.001). A significant difference was also found in the SUR values between the cases of early PD and control group (P < 0.001).No significant difference was noted among the SUR values in different Hoehn and Yahr stages. Conclusion For clinical practice, both the visual analysis and the quantitative parameters of 99m Tc-TRODAT-1 single- photon emission computed tomography/computed tomography showed usefulness in distinguishing cases of PD and PPS from the healthy individuals. Nucl Med Commun 00:000–000 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. Nuclear Medicine Communications 2018, 00:000–000 Keywords: dopamine transporter, Parkinson’s disease, parkinsonian syndromes, SPECT/CT, 99m Tc-TRODAT-1 Departments of a Nuclear Medicine and b Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, Punjab, India Correspondence to Bhagwant R. Mittal, MD, Department of Nuclear Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, Punjab, India Fax: + 91 172 274 2858; e-mail: brmittal@yahoo.com Received 26 October 2017 Revised 7 December 2017 Accepted 2 January 2018 Introduction Parkinson’s disease (PD) is an age-related neurodegenera- tive disease affecting nearly 1% of individuals in the age group of 65–70 years and 3% of individuals above the age group of 80 years [1]. It ranks second only to Alzheimer’s disease in terms of prevalence and consequent morbidity, economic, and social burden [1]. Slow and progressive deterioration of the dopaminergic neurons in the substantia nigra pars compacta is noted in PD. Insufficiency of dopa- mine in the basal ganglia because of dopaminergic neuronal degeneration leads to various motor and nonmotor symp- toms. The molecular and cellular pathology precedes the onset of the motor symptoms by years. It is during this time that the patient experiences premotor symptoms such as sleep disturbances, constipation, mood disorders, etc. [2]. The diagnosis of PD is made solely on the basis of clinical features and the related experience and knowledge of the physician. Therefore, the diagnosis of PD is complex and especially challenging in the early course of disease. A correct diagnosis of PD is not only important for counseling, prognostication, and proper treatment but also to carry out epidemiologic and pharmacologic studies. Further, an early diagnosis of PD will enable early administration of neuro- protective agents that can prevent dopaminergic neuronal loss [3]. Anatomic imaging modalities such as MRI and computed tomography (CT) are neither helpful in diagnosing PD nor are they beneficial in monitoring the disease-related chan- ges over the course of time [4]. Disease-specific biomarkers may help clinicians and researchers in early and more pre- cise diagnosis of parkinsonian disorders [5]. Biomarkers can aid the objective assessment of the disease, its progression, and response evaluation, which can further enable research for the development of new therapies for this disease [6]. Original article 0143-3636 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/MNM.0000000000000802 Copyright r 2018 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.