Practical Application of DaTQUANT with Optimal Threshold for Diagnostic Accuracy of Dopamine Transporter SPECT

Abstract

Evaluation of Parkinsonian Syndromes (PS) with Ioflupane iodine-123 dopamine transporter single photon emission computed tomography (DaT-SPECT), in conjunction with history and clinical examination, aids in diagnosis. FDA-approved, semi-quantitative software, DaTQUANTTM (GE Healthcare, Chicago, IL, USA) is available to assist in interpretation. This study aims to evaluate the optimal variables and thresholds of DaTQUANT to yield the optimal diagnostic accuracy. It is a retrospective review with three different patient populations. DaT-SPECT images from all three study groups were evaluated using DaTQUANTTM software, and both single and multi-variable logistic regression were used to model PS status. The optimal models were chosen via accuracy, sensitivity, and specificity, then evaluated on the other study groups. Among single variable models, the posterior putamen yielded the highest accuracy (84% to 95%), while balancing sensitivity and specificity. Multi-variable models did not substantially improve the accuracy. When the optimal single variable models for each group were used to evaluate the remaining two groups, comparable results were achieved. In typical utilization of DaT-SPECT for differentiation between nigrostriatal degenerative disease (NSDD) and non-NSDD, the posterior putamen was the single variable that yielded the highest accuracy across three different patient populations. The posterior putamen’s recommended thresholds for DaTQUANT are SBR ≤ 1.0, z-score of ≤−1.8 and percent deviation ≤ −0.34.

Presynaptic Dopaminergic Imaging Characterizes Patients with REM Sleep Behavior Disorder Due to Synucleinopathy

“…No clear guidelines are available for defining when DaT‐SPECT should be considered abnormal; thus, we chose to use the most common criteria that identify DaT‐SPECT as abnormal when at least one of the putamen had a z‐score < −1.5, 20 even if different cutoff values have been proposed 21 . For example, a recent study showed that a z‐score cutoff of −1.27 at putamen level best differentiated PD patient from essential tremor patients, while a cutoff of −0.96 was the most accurate in supporting DLB diagnosis 22 …”

Serial Nigrostriatal Dopaminergic Imaging in Mild Cognitive Impairment With Lewy Bodies, Alzheimer Disease, and Age-Matched Controls

“…123[I]-FP-CIT uptake was measured using specific binding ratios (SBRs) obtained from DaTQUANT v2.0 software (GE Healthcare, Chalfont St. Giles, UK). 16 The software registers the scan to a normal database and overlays volumes of interest over the whole striatum, caudate, and putamen as well as a reference region in the occipital lobe representing nonspecific, displaceable activity. The SBR is defined as the ratio between the background subtracted count density in the striatal volume and the count density in the background volume.…”

Practical use of DAT SPECT imaging in diagnosing dementia with Lewy bodies: a US perspective of current guidelines and future directions

“…While visual assessment is currently standard, there is growing interest in performing semi-quantitative analysis in DAT SPECT interpretation as an adjunct to visual assessment. Semi-quantification of the DAT SPECT signal measures the signal-to-background ratio at the striatum, including the posterior putamen, an area of the striatum most sensitive to neurodegeneration ( 66 ). It also provides a numerical assessment for more balanced loss, which can be challenging to interpret when a minimal change in the shape of the striata is present.…”

“…In clinical and radiologic integration, the interpretation of the DAT SPECT imaging is closely coordinated with the patient’s clinical symptoms. For instance, in early PD, an asymmetric reduction in tracer uptake, particularly in the left putamen compared to the caudate nucleus (especially the posterior putamen), is often observed ( 66 ). In contrast, a more symmetric putaminal loss assessed with DAT SPECT is frequently observed in DLB and other atypical parkinsonian syndromes such as Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) ( 64 ).…”