Parkinsonism Associated with Pathological 123I-FP-CIT SPECT (DaTSCAN) Results as the Initial Manifestation of Sporadic Creutzfeldt-Jakob Disease

I123-FP-CIT (DaTSCAN) SPECT beyond the Most Common Causes of Parkinsonism: A Systematic Review

BACKGROUND

As the diagnosis of Parkinson's disease (PD) is fundamentally clinical, the usefulness of ioflupane (123I) single-photon emission computed tomography (SPECT) or DaTSCAN as a diagnostic tool has been a matter of debate for years. The performance of DaTSCAN is generally recommended in the follow-up of patients with a clinically uncertain diagnosis, especially in those with a suspected essential tremor, drug-induced parkinsonism, or vascular parkinsonism. However, there is a dearth of DaTSCAN findings regarding neurodegenerative parkinsonisms besides PD and atypical parkinsonisms. To date, a specific nigrostriatal dopamine uptake pattern that would help differentiate PD from the most frequent atypical parkinsonisms is yet to be described. This fact is further complicated by the possible visualization of abnormalities in the uptake pattern in patients with rarer neurodegenerative parkinsonisms.

OBJECTIVES

We aimed to summarize the current literature regarding DaTSCAN findings in patients with rare neurodegenerative parkinsonisms.

METHODS

The PubMed database was systematically screened for studies in English or Spanish up to October 15, 2023, using search terms "DaTSCAN", "ioflupane", "DaT-SPECT", "123I-FP-CIT SPECT", "dopamine transporter imaging", and "[123I] FP-CIT SPECT". Duplicated publications and studies regarding PD, atypical parkinsonisms, dystonia-parkinsonism, essential tremor, and parkinsonism due to non-degenerative causes were excluded.

RESULTS

The obtained results were reviewed and summarized, including DaTSCAN findings in fragile X-associated tremor/ataxia syndrome, prion diseases, Huntington's disease, spinocerebellar ataxia, hereditary spastic paraparesis, metabolic disorders, and other diseases (anti-IgLON5 disease, ring chromosome 20 syndrome, chorea-acanthocytosis, and neuronal ceroid lipofuscinosis).

CONCLUSIONS

This review highlights the need to determine in the future the utility and cost-effectiveness of DaTSCAN, both as a diagnostic and a prognostic tool, in patients with parkinsonian symptoms in rare neurodegenerative diseases.

F198S Gerstmann-Sträussler-Scheinker Syndrome With Parkinsonism, Dyskinesia, and Abnormal (I-123)-FP-CIT Single-Photon Emission Computed Tomography: A Case Report

Gerstmann-Sträussler-Scheinker syndrome (GSS) is an autosomal dominant neurodegenerative disease caused by point mutations in the prion protein gene (PRNP). While variable, the clinical presentation typically encompasses progressive cerebellar ataxia, pyramidal signs, and cognitive impairment. Here, we report a case of F198S-associated GSS manifesting levodopa-responsive parkinsonism, levodopa-induced dyskinesia, and an abnormal (I-123)-FP-CIT single-photon emission computed tomography (DaT-SPECT). A 66-year-old male patient presented with six years of progressive recall and language impairment, with an initial impression of primary progressive aphasia. Over time he developed progressive cerebellar ataxia and akinetic parkinsonism. There was a family history of ataxia in multiple family members. Levodopa was prescribed up to 450 mg per day without benefit. Genetic testing at age 69 revealed a heterozygous F198S mutation in the PRNP gene, with MV heterozygosity at codon 129. At age 70, he developed mild generalized choreiform dyskinesia. Levodopa was discontinued, resulting in the resolution of dyskinesia with a concomitant marked worsening of akinetic parkinsonism. DaT-SPECT demonstrated bilaterally reduced putaminal binding. This case highlights that GSS can resemble atypical parkinsonism both clinically and with DaT-SPECT imaging. Taking a salient family history and other clinical features into consideration, GSS should be added to the differential diagnoses of such patients.

Radiological assessment of dementia: the Italian inter-society consensus for a practical and clinically oriented guide to image acquisition, evaluation, and reporting

Background

Radiological evaluation of dementia is expected to increase more and more in routine practice due to both the primary role of neuroimaging in the diagnostic pathway and the increasing incidence of the disease. Despite this, radiologists often do not follow a disease-oriented approach to image interpretation, for several reasons, leading to reports of limited value to clinicians. In our work, through an intersocietal consensus on the main mandatory knowledge about dementia, we proposed a disease-oriented protocol to optimize and standardize the acquisition/evaluation/interpretation and reporting of radiological images. Our main purpose is to provide a practical guideline for the radiologist to help increase the effectiveness of interdisciplinary dialogue and diagnostic accuracy in daily practice.

Results

We defined key clinical and imaging features of the dementias (A), recommended MRI protocol (B), proposed a disease-oriented imaging evaluation and interpretation (C) and report (D) with a glimpse to future avenues (E). The proposed radiological practice is to systematically evaluate and score atrophy, white matter changes, microbleeds, small vessel disease, consider the use of quantitative measures using commercial software tools critically, and adopt a structured disease-oriented report.

Summary statement

In the expanding field of cognitive disorders, the only effective assessment approach is the standardized disease-oriented one, which includes a multidisciplinary integration of the clinical picture, MRI, CSF and blood biomarkers and nuclear medicine.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11547-022-01534-0.

DaT Scan "Abnormality" in Hyperglycemic-Hemichorea

Background

Hyperglycemic-hemichorea is a well-established clinical entity which leads to signal changes on brain MRI. We are reporting a case of hyperglycemic-hemichorea where the DaT scan showed reduced uptake bilaterally.

Case Report

A 57-year-old female was seen in the clinic for hemichorea due to hyperglycemia. Her brain magnetic resonance imaging (MRI) showed increased T1 signal intensity in bilateral lenticular nuclei and the DaT scan showed reduced uptake on both sides.

Discussion

This case highlights the importance of performing a DaT scan in the correct clinical context, as an abnormality on brain MRI can lead to false-positive DaT scan results.