Follow-Up Findings in Multiple System Atrophy from [123I]Ioflupane Single-Photon Emission Computed Tomography (SPECT): A Prospective Study

Abstract

Background: Multiple system atrophy (MSA) is subdivided into two types: MSA-P (parkinsonian) and MSA-C (cerebellar). Brain SPECT allows for the detection of nigrostriatal involvement, even in the early stages. To date, the scientific literature does not show a consensus on how to follow-up MSA, especially MSA-C. Our aim was to analyze the diagnostic effectiveness of repeat [123I]Ioflupane SPECT for the follow-up of MSA. Methods: A longitudinal observational study on 22 MSA patients (11 males and 11 females). Results: Significant changes were obtained in the quantitative SPECT assessments in the three Striatum/Occipital indices. The qualitative SPECT diagnosis did not show differences between the initial and evolving SPECT, but the neurologist’s clinical suspicion did. Our results showed a brain deterioration of around 31% at 12 months, this being the optimal cut-off for differentiating a diseased subject (capable of solving diagnostic error rate). Previous imaging tests were inconclusive, as they showed less deterioration in the SPECT and quantitative assessments with respect to the group of confirmed patients. Repeated SPECT increased the diagnostic sensitivity (50% vs. 75%) and positive predictive value (72.73% vs. 77%). In addition, repeated SPECT proved decisive in the diagnosis of initial inconclusive cases. Conclusion: Repeat SPECT at 12 months proves useful in the diagnosis and follow-up of MSA.

Comparative Study between the Diagnostic Effectiveness of Brain SPECT with [123I]Ioflupane and [123I]MIBG Scintigraphy in Multiple System Atrophy

“…Secondly, they request [ 123 I]MIBG scintigraphy to make a differential diagnosis of PD or Lewy body dementia versus other atypical parkinsonisms (MSA, progressive supranuclear palsy, or corticobasal degeneration). These findings support the results obtained in our previous research, in which we advocated for the need to include both imaging studies in the diagnostic algorithm of MSA [36,45].…”

“…Moreover, based on our hospital protocol, when the patient already has an established diagnosis of MSA, it is not appropriate to perform both neuroimaging techniques. Consequently, we were only able to follow up with a subsample of these patients with one of the two techniques, namely [ 123 I]Ioflupane SPECT [36].…”

“…It consists of a qualitative assessment of the image (visually performed by the nuclear medicine physician) which can be assisted by the quantitative assessment performed by specific software. The result will typically show bilateral striatal hypocaptation, usually more symmetrical with respect to other entities such as Parkinson's disease (PD), and the presence of non-specific cortical activity (background) may also be observed [36]. In contrast, cardiac innervation scintigraphy with [ 123 I]MIBG reflects the state of the ANS by binding to the noradrenaline transporters expressed in the presynaptic terminals of postganglionic sympathetic neurons.…”