123I xSPECT Quant enables standardized quantification in unclear motion disorder

By Misty Long, R.T. (R)(N)
Data courtesy of CHUV, Nuclear Medicine, Lausanne, Switzerland
|04/08/2017

Two patients were evaluated for unclear motion disorders not distinctly characterizable to a particular disease process upon clinical examination. The first was a 47-year-old female who was assessed for a tremor of the left upper limb and lower limb. The second patient was a 77-year-old male with tremors in the upper right limb persisting for almost two years with increased progression. 123I Ioflupane SPECT/CT studies using xSPECT Quant™ technology were per-formed on both patients to determine striatal dopamine transporter (DaT) binding potential and evaluate tracer uptake.

There is normal tracer uptake and symmetrical tracer distribution of both striatum, and of the caudate lobe and putamen of the female referred to as patient 1 (see Figure 1).

xSPECT Quant, in combination with visual analysis, shows normal tracer uptake.

Conclusion

Patient 1 does not demonstrate disease-specific changes for Parkinson’s disease and additional diagnostics are needed.

Conversely, in the second patient the DaT scan images show pathologic uptake with deceased dopaminergic activity in bilateral striatal regions, predominant on the putamin, especially on the left side, which is consistent with Parkinson’s Disease (see Figure 1).

Conclusion

The second patient shows typical decrease of the dopaminergic metabolism with high probability of Parkinson’s disease. In addition to the visual read, xSPECT Quant using 123I in DaT scan enables standardized quantification assessment, as shown in Figure 1.

Studies compared normal and pathological tracer uptake in the caudate and putamen.Data courtesy of CHUV, Nuclear Medicine, Lausanne, Switzerland
Figure 1

SPECT/CT DaT scans can aid in evaluating unclear motion disorders caused by neurological disease. The striatum receives innervation by dopaminergic projections from the substantia nigra (SN). Here, the synapses are relasing the neurotransmitter dopamine in the synaptic gap where it has been uptaken by the dopamine receptors.

123I Ioflupane binds to the presynaptic dopamine transporter, responsible for the reuptake of released dopamine by the neurosynapses. The degeneration of the presynaptic DaT can be pathog-nomonic for Parkinson’s disease. The diagnosis of an abnormal scan can influence medical treatment more when it is abnormal, compared to when it is normal.1

The Society of Nuclear Medicine and Molecular Imaging (SNMMI) and the European Association of Nuclear Medicine (EANM) concur that the complexity of human conditions makes it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment.2

Looking to account for unique patient qualities and improve the quality of ser-vice to patients, Söederlund et al. has shown that a combined approach using visual assessment and semi-quantitative analysis of tracer binding created more reproducible clinical reporting of 123I-FP-CIT SPECT studies. Also recommended was that physicians should have access to both striatal binding ratios (SBR) and caudate- to-putamen ratios (CPR) data to minimize inter-observer variability.3 With the advent of xSPECT Quant for 123I, the next logical step beyond ratio analysis is made. During the last couple of years, it has been shown that ratio has improved reading and comparison in this examination.3

Built upon xSPECT™ technology, xSPECT Quant offers accuracy and reproducibility of < 10% uncertainty in reference to NIST (National Institute of Standards and Technology), an external standard. Introducing xSPECT Quant potentially reduces interobserver variability by standardizing uptake values, which allows reliable dis-ease detection and evaluation of therapy response across imaging centers, cameras and dose calibrators. With this, a new chapter is about to begin.In research, it has been demonstrated, that using more detailed methodology and looking into finer details of meta-bolic changes in the course of the dis-ease, does have an impact on early diagnosis and can improve detection.4

SPECT

 

Injected dose patient 1

5.2 mCi (195 MBq)

Injected dose patient 2

4.7 mCi (177 MBq)

Scan delay

4 hours

Acquisition

15 min

CT

 

Tube voltage

110 kV

Tube current

12 mAs

Slice collimation

0.5 mm

Slice thickness

3.0 mm

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