Semiquantitative Analysis of Dopamine Transporter Scans in Patients With Parkinson Disease

There are a number of quantitative software packages for use with DAT-SPECT imaging... these ideally need to be compared head to head to determine which is the most useful... particularly in the prodromal phase the change in DAT-SPECT may be slight and hard to discern through visual reads. This is a good use of PPMI data which is now available for download and use...

There likely exists a floor effect of binding in established PD and the slope of change in binding is likely to be greatest in the early stages (pre- and immediately post- diagnosis)... interested in the correlation between SBR and motor severity here too... 

Clin Nucl Med. 2017 Nov 3. doi: 10.1097/RLU.0000000000001885. [Epub ahead of print]
Tinaz S, Chow C, Kuo PH, Krupinski EA, Blumenfeld H, Louis ED, Zubal G.

https://insights.ovid.com/pubmed?pmid=29112012

PURPOSE: Dopamine transporter (DaT) imaging is an adjunct diagnostic tool in parkinsonian disorders. Interpretation of DaT scans is based on visual reads. SBRquant is an automated method that measures the striatal binding ratio (SBR) in DaT scans, but has yet to be optimized. We aimed to (1) optimize SBRquant parameters to distinguish between patients with Parkinson disease (PD) and healthy controls using the Parkinson's Progression Markers Initiative (PPMI) database and (2) test the validity of these parameters in an outpatient cohort.

METHODS: For optimization, 336 DaT scans (215 PD patients and 121 healthy controls) from the PPMI database were used. Striatal binding ratio was calculated varying the number of summed transverse slices (N) and positions of the striatal regions of interest (d). The resulting SBRs were evaluated using area under the receiver operating characteristic curve. The optimized parameters were then applied to 77 test patients (35 PD and 42 non-PD patients). Striatal binding ratios were also correlated with clinical measures in the PPMI-PD group.

RESULTS: The optimal parameters discriminated the training groups in the PPMI cohort with 95.8% sensitivity and 98.3% specificity (lowest putamen SBR threshold, 1.037). The same parameters discriminated the groups in the test cohort with 97.1% sensitivity and 100% specificity (lowest putamen SBR threshold, 0.875). A significant negative correlation (r = -0.24, P = 0.0004) was found between putamen SBRs and motor severity in the PPMI-PD group.

CONCLUSIONS: SBRquant discriminates DaT scans with high sensitivity and specificity. It has a high potential for use as a quantitative diagnostic aid in clinical and research settings.