A Comparative value of 123 I-Ioflupane single photon emission computed tomography (DaTscan) and transcranial sonography (TCS) for Parkinson’s disease diagnostics: A 8-year retrospective study

Abstract

Introduction: The aim of the study was to: 1) evaluate diagnostic accuracy of DaTscan and TCS for the patients with idiopathic Parkinson’s disease (IPD); 2) estimate the relationship between two imaging methods. Methods: A retrospective study of 115 out of 254 patients in total was performed, who were investigated at Kaunas Clinics from 2006 until 2013 (Figure 1). An experience of DaTscan imaging at Kaunas Clinics exists since 2006 (123 I-Ioflupane, GE, the UK), and of TCS - since 2010 (Voluson 730 Expert, GE, Austria). The threshold values of substantia nigra hyperechogenicity (TCS-SN+): moderate ≥0.20cm2, high ≥0.26cm2. Results: The majority of the referred for imaging patients were female 70 (60.9%), the mean (±SD) age was 63.6±13y (min. 22-max. 85y), median symptom duration 2y (min.0.05- max. 40y). For those patients whom IPD was diagnosed n=59 (51.3%), median stage according to Hoehn-Yahr was 2 (min.1- max.4), 34 (57.6%) were tremor predominant. The main DaTscan and TCS accuracy findings are presented in Figure 2. For 53 (46.1%) patients diagnoses changed after imaging: 26 (49.1%) were reclassified to essential tremor, 17 (32.1%) to IPD (p=0.003). For 86.1% patients, DaTscan was abnormal, who were TCS-SN+. TCS missed 3 cases (7%) when SN <0.20 cm2 with abnormal DaTscan, and 6 (14%) - at <0.26 cm2. Conclusions: A high percentage of diagnostic reclassification (46.1%) after imaging represents high diagnostic impact of two methods. For the majority (86.1%), when TCS was abnormal, DaTscan reduced binding was detected, however no significant correlation between the tests was found.