Comparison of two methods for semiquantitative evaluation of DaTSCAN

Objectives Semiquantitative analysis as a supplement of visual assessment plays an important role in evaluation of DaTSCAN images. Our goal is to compare two semiquantitative methods for evaluation of DaTSCAN and assess their clinical value.

Methods Sixteen DaTSCAN studies in 11 patients with Parkinson’s Disease (PD) and 5 control subjects performed between Jan 2011 and Apr 2013 were retrospectively analyzed. Images were processed with two techniques: 1) Automated semiquantification based on the Brain Analysis Software (BRASS) and 2) Manual regions of interest using PMOD software. The occipital cortex served as reference tissue. Specific binding ratios of the entire striatum, the bilateral caudate nuclei, and the bilateral putamen to the occipital cortex were calculated as (striatum-reference)/reference. Correlations between all these striatal ratios and the Unified Parkinson’s Disease Rating Scale (UPDRS) were calculated.

Results With Brass in controls the average ratios of left caudate, left putamen, right caudate, right putamen and entire striatum were 2.102, 1.934, 2.036, 1.810 and 1.971, while in the PD group they were 1.313, 0.961, 1.257, 0.913 and 1.111, respectively. The striatal binding ratios were significantly higher in the control group (P＜0.05) except in the right caudate. With PMOD the average ratios of the left caudate, left putamen, right caudate, right putamen and entire striatum of controls were 2.547, 3.171, 2.546, 2.937 and 2.8 in controls, and 1.921, 1.491, 1.803, 1.473 and 1.452 in PD。Again, these differences were significant (P＜0.05), except in the right caudate (P＞0.05). UPDRS was higher in the PD group than in the control group (31.125 vs 3.8, P＜0.05 ). The striatal ratios from both methods showed negative correlation with UPDRS (r:－0.562～－0.877, P＜0.05).

Conclusions Semiquantitative evaluation of DaTSCAN with either BRASS or PMOD methods can differentiate PD from control subjects. The striatal ratios of both methods show negative correlation with the severity of PD