Single Photon Emission Computed Tomography/Positron Emission Tomography Molecular Imaging for Parkinsonism: A Fast-Developing Field

Unrealistic Data Augmentation Improves the Robustness of Deep Learning-Based Classification of Dopamine Transporter SPECT Against Variability Between Sites and Between Cameras

We propose strongly unrealistic data augmentation to improve the robustness of convolutional neural networks (CNNs) for automatic classification of dopamine transporter SPECT against the variability between sites and between cameras. Methods: A CNN was trained on a homogeneous dataset comprising 1,100 123I-labeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane SPECT images using strongly unrealistic data augmentation based on gaussian blurring and additive noise. Strongly unrealistic data augmentation was compared with no augmentation and intensity-based nnU-Net augmentation on 2 independent datasets with lower (n = 645) and considerably higher (n = 640) spatial resolution. Results: The CNN trained with strongly unrealistic augmentation achieved an overall accuracy of 0.989 (95% CI, 0.978-0.996) and 0.975 (95% CI, 0.960-0.986) in the independent test datasets, which was better than that without (0.960, 95% CI, 0.942-0.974; 0.953, 95% CI, 0.934-0.968) and with nnU-Net augmentation (0.972, 95% CI, 0.956-0.983; 0.950, 95% CI, 0.930-0.966) (all McNemar P < 0.001). Conclusion: Strongly unrealistic data augmentation results in better generalization of CNN-based classification of 123I-labeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane SPECT images to unseen acquisition settings. We hypothesize that this can be transferred to other nuclear imaging applications.

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.

Automated identification of uncertain cases in deep learning-based classification of dopamine transporter SPECT to improve clinical utility and acceptance

PURPOSE

Deep convolutional neural networks (CNN) are promising for automatic classification of dopamine transporter (DAT)-SPECT images. Reporting the certainty of CNN-based decisions is highly desired to flag cases that might be misclassified and, therefore, require particularly careful inspection by the user. The aim of the current study was to design and validate a CNN-based system for the identification of uncertain cases.

METHODS

A network ensemble (NE) combining five CNNs was trained for binary classification of [123I]FP-CIT DAT-SPECT images as "normal" or "neurodegeneration-typical reduction" with high accuracy (NE for classification, NEfC). An uncertainty detection module (UDM) was obtained by combining two additional NE, one trained for detection of "reduced" DAT-SPECT with high sensitivity, the other with high specificity. A case was considered "uncertain" if the "high sensitivity" NE and the "high specificity" NE disagreed. An internal "development" dataset of 1740 clinical DAT-SPECT images was used for training (n = 1250) and testing (n = 490). Two independent datasets with different image characteristics were used for testing only (n = 640, 645). Three established approaches for uncertainty detection were used for comparison (sigmoid, dropout, model averaging).

RESULTS

In the test data from the development dataset, the NEfC achieved 98.0% accuracy. 4.3% of all test cases were flagged as "uncertain" by the UDM: 2.5% of the correctly classified cases and 90% of the misclassified cases. NEfC accuracy among "certain" cases was 99.8%. The three comparison methods were less effective in labelling misclassified cases as "uncertain" (40-80%). These findings were confirmed in both additional test datasets.

CONCLUSION

The UDM allows reliable identification of uncertain [123I]FP-CIT SPECT with high risk of misclassification. We recommend that automatic classification of [123I]FP-CIT SPECT images is combined with an UDM to improve clinical utility and acceptance. The proposed UDM method ("high sensitivity versus high specificity") might be useful also for DAT imaging with other ligands and for other binary classification tasks.

Nanoscale contrast agents: A promising tool for ultrasound imaging and therapy

Nanoscale contrast agents have emerged as a versatile platform in the field of biomedical research, offering great potential for ultrasound imaging and therapy. Various kinds of nanoscale contrast agents have been extensively investigated in preclinical experiments to satisfy diverse biomedical applications. This paper provides a comprehensive review of the structure and composition of various nanoscale contrast agents, as well as their preparation and functionalization, encompassing both chemosynthetic and biosynthetic strategies. Subsequently, we delve into recent advances in the utilization of nanoscale contrast agents in various biomedical applications, including ultrasound molecular imaging, ultrasound-mediated drug delivery, and cell acoustic manipulation. Finally, the challenges and prospects of nanoscale contrast agents are also discussed to promote the development of this innovative nanoplatform in the field of biomedicine.

In vivo cerebral metabolic and dopaminergic characteristics in multiple system atrophy with orthostatic hypotension

PURPOSE

Multiple system atrophy (MSA) is a rare neurodegenerative disease, often presented with orthostatic hypotension (OH), which is a disabling symptom but has not been very explored. Here, we investigated MSA patients with OH by using positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) and 11C-N-2-carbomethoxy-3-(4-fluorophenyl)-tropane (11C-CFT) for in vivo evaluation of the glucose metabolism and dopaminergic function of the brain.

METHODS

Totally, 51 patients with MSA and 20 healthy controls (HC) who underwent 18F-FDG PET/CT were retrospectively enrolled, among which 24 patients also underwent 11C-CFT PET/CT. All patients were divided into MSA-OH(+) and MSA-OH(-) groups. Then, statistical parametric mapping (SPM) method was used to reveal the regional metabolic and dopaminergic characteristics of MSA-OH(+) compared with MSA-OH(-). Moreover, the metabolic networks of MSA-OH(+), MSA-OH(-) and HC groups were also constructed and analyzed based on graph theory to find possible network-level changes in MSA patients with OH.

RESULTS

The SPM results showed significant hypometabolism in the pons and right cerebellar tonsil, as well as hypermetabolism in the left parahippocampal gyrus and left superior temporal gyrus in MSA-OH(+) compared with MSA-OH(-). A reduced 11C-CFT uptake in the left caudate was also shown in MSA-OH(+) compared with MSA-OH(-). In the network analysis, significantly reduced local efficiency and clustering coefficient were shown in MSA-OH(+) compared with HC, and decreased nodal centrality in the frontal gyrus was found in MSA-OH(+) compared with MSA-OH(-).

CONCLUSION

In this study, the changes in glucose metabolism in the pons, right cerebellar tonsil, left parahippocampal gyrus and left superior temporal gyrus were found closely related to OH in MSA patients. And the decreased presynaptic dopaminergic function in the left caudate may contribute to OH in MSA. Taken together, this study provided in vivo pathophysiologic information on MSA with OH from neuroimaging approach, which is essential for a better understanding of MSA with OH.

Effects of stepped speech rehabilitation and psychological intervention on speech disorders and cognitive function in Parkinson disease patients

To examine the impact of stepwise speech rehabilitation exercise therapy in the treatment of patients with Parkinson speech problems under psychological intervention on clinical results and cognitive functioning. Parkinson speech disorder patients who met the inclusion criteria were selected and divided into a control group and an observation group for training respectively. The control group used conventional nursing methods, including training in orofacial movement, vocalization, pitch, volume and breath control. The observation group used stepwise speech rehabilitation exercise intervention combined with psychotherapy nursing programme. In the statistical analysis, independent sample t-test and chi-square test were used to test the significance of the data processing methods. In the statistical analysis of baseline functional level (P > .05). The difference was not statistically significant. After 7 weeks of training, the mFDA level and speech intelligibility increased in both the observation and control groups. From the situation analysis of "modified drinking test" and the comparison of UPDRS-I scores, it can be seen that dysphagia and Parkinson dysphasia were reduced in both groups after training. The observation group spontaneous speech dimension was greater than the control group by around 0.07 in the aphasia comparison. Both groups displayed an upward trend in their MMSE and Montreal Cognitive Assessment (MoCA) when measuring cognitive function; the evaluation of P300, constructive function, and quality of life revealed this. The observation group P300 potential score was 0.13 points higher than that of the control group. The therapeutic training of stepped speech rehabilitation exercise care combined with psychological intervention has significant nursing effects on patients with Parkinson disease speech disorders, and the patients' cognitive functions have been effectively improved.

Brain FDG-PET correlates of saccadic disorders in early PSP

BACKGROUND

New diagnostic criteria of Progressive Supranuclear Palsy (PSP) have highlighted the interest of Eye Movement Records (EMR) at the early stage of the disease.

OBJECTIVES

To investigate the metabolic brain correlates of ocular motor dysfunction using [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) in early PSP.

METHODS

Retrospective observational descriptive study on longitudinal data with patients who underwent EMR and FDG-PET at the stage of suggestive and possible PSP according to Movement Disorders Society criteria. Longitudinal follow-up enables to confirm diagnosis of probable PSP. Using the Statistical Parametric Mapping software, we performed whole-brain voxel-based correlations between oculomotor variables and FDG-PET metabolism.

RESULTS

Thirty-seven patients with early PSP who fulfilled criteria of probable PSP during the follow-up were included. Decrease in the gain of vertical saccades correlated with reduced metabolism in Superior Colliculi (SC). We also found a positive correlation between mean velocity of horizontal saccades and SC metabolism as well as dorsal nuclei in the pons. Finally, increase in horizontal saccades latencies correlated with decrease of posterior parietal metabolism.

CONCLUSIONS

These findings suggest the early involvement of SC in saccadic dysfunction in the course of PSP.

An update on pathogenesis and clinical scenario for Parkinson's disease: diagnosis and treatment

In severe cases, Parkinson's disease causes uncontrolled movements known as motor symptoms such as dystonia, rigidity, bradykinesia, and tremors. Parkinson's disease also causes non-motor symptoms such as insomnia, constipation, depression and hysteria. Disruption of dopaminergic and non-dopaminergic neural networks in the substantia nigra pars compacta is a major cause of motor symptoms in Parkinson's disease. Furthermore, due to the difficulty of clinical diagnosis of Parkinson's disease, it is often misdiagnosed, highlighting the need for better methods of detection. Treatment of Parkinson's disease is also complicated due to the difficulties of medications passing across the blood-brain barrier. Moreover, the conventional methods fail to solve the aforementioned issues. As a result, new methods are needed to detect and treat Parkinson's disease. Improved diagnosis and treatment of Parkinson's disease can help avoid some of its devastating symptoms. This review explores how nanotechnology platforms, such as nanobiosensors and nanomedicine, have improved Parkinson's disease detection and treatment. Nanobiosensors integrate science and engineering principles to detect Parkinson's disease. The main advantages are their low cost, portability, and quick and precise analysis. Moreover, nanotechnology can transport medications in the form of nanoparticles across the blood-brain barrier. However, because nanobiosensors are a novel technology, their use in biological systems is limited. Nanobiosensors have the potential to disrupt cell metabolism and homeostasis, changing cellular molecular profiles and making it difficult to distinguish sensor-induced artifacts from fundamental biological phenomena. In the treatment of Parkinson's disease, nanoparticles, on the other hand, produce neurotoxicity, which is a challenge in the treatment of Parkinson's disease. Techniques must be developed to distinguish sensor-induced artifacts from fundamental biological phenomena and to reduce the neurotoxicity caused by nanoparticles.

Biomarkers for parkinsonian disorders in CNS-originating EVs: promise and challenges

Extracellular vesicles (EVs), including exosomes, microvesicles, and oncosomes, are nano-sized particles enclosed by a lipid bilayer. EVs are released by virtually all eukaryotic cells and have been shown to contribute to intercellular communication by transporting proteins, lipids, and nucleic acids. In the context of neurodegenerative diseases, EVs may carry toxic, misfolded forms of amyloidogenic proteins and facilitate their spread to recipient cells in the central nervous system (CNS). CNS-originating EVs can cross the blood-brain barrier into the bloodstream and may be found in other body fluids, including saliva, tears, and urine. EVs originating in the CNS represent an attractive source of biomarkers for neurodegenerative diseases, because they contain cell- and cell state-specific biological materials. In recent years, multiple papers have reported the use of this strategy for identification and quantitation of biomarkers for neurodegenerative diseases, including Parkinson's disease and atypical parkinsonian disorders. However, certain technical issues have yet to be standardized, such as the best surface markers for isolation of cell type-specific EVs and validating the cellular origin of the EVs. Here, we review recent research using CNS-originating EVs for biomarker studies, primarily in parkinsonian disorders, highlight technical challenges, and propose strategies for overcoming them.

Triphenylamine-equipped 1,8-naphthaolactam: a versatile scaffold for the custom design of efficient subcellular imaging agents

Fluorescence imaging has enabled much progress in biological fields, while the evolution of commercially available dyes has lagged behind their advanced applications. Herein, we launch triphenylamine-equipped 1,8-naphthaolactam (NP-TPA) as a versatile scaffold for the custom design of an efficient subcellular imaging agent (NP-TPA-Tar), given its bright and constant emissions in various states, significant Stokes shifts, and facile modifiability. The resultant four NP-TPA-Tars maintain excellent emission behavior with targeted modifications and can map the spatial distribution of lysosomes, mitochondria, endoplasmic reticulum, and plasma membrane in Hep G2 cells. Compared to its commercial counterpart, NP-TPA-Tar has a 2.8-25.2 fold increase in Stokes shift, a 1.2-1.9 fold increase in photostability, enhanced targeting capability, and comparable imaging efficiency even at low concentrations of 50 nM. This work will help to accelerate the update of current imaging agents and super-resolution and real-time imaging in biological applications.

Recent Advances in Imaging Agents Anchored with pH (Low) Insertion Peptides for Cancer Theranostics

The acidic extracellular microenvironment has become an effective target for diagnosing and treating tumors. A pH (low) insertion peptide (pHLIP) is a kind of peptide that can spontaneously fold into a transmembrane helix in an acidic microenvironment, and then insert into and cross the cell membrane for material transfer. The characteristics of the acidic tumor microenvironment provide a new method for pH-targeted molecular imaging and tumor-targeted therapy. As research has increased, the role of pHLIP as an imaging agent carrier in the field of tumor theranostics has become increasingly prominent. In this paper, we describe the current applications of pHLIP-anchored imaging agents for tumor diagnosis and treatment in terms of different molecular imaging methods, including magnetic resonance T1 imaging, magnetic resonance T2 imaging, SPECT/PET, fluorescence imaging, and photoacoustic imaging. Additionally, we discuss relevant challenges and future development prospects.

Translational molecular imaging and drug development in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that primarily affects elderly people and constitutes a major source of disability worldwide. Notably, the neuropathological hallmarks of PD include nigrostriatal loss and the formation of intracellular inclusion bodies containing misfolded α-synuclein protein aggregates. Cardinal motor symptoms, which include tremor, rigidity and bradykinesia, can effectively be managed with dopaminergic therapy for years following symptom onset. Nonetheless, patients ultimately develop symptoms that no longer fully respond to dopaminergic treatment. Attempts to discover disease-modifying agents have increasingly been supported by translational molecular imaging concepts, targeting the most prominent pathological hallmark of PD, α-synuclein accumulation, as well as other molecular pathways that contribute to the pathophysiology of PD. Indeed, molecular imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can be leveraged to study parkinsonism not only in animal models but also in living patients. For instance, mitochondrial dysfunction can be assessed with probes that target the mitochondrial complex I (MC-I), while nigrostriatal degeneration is typically evaluated with probes designed to non-invasively quantify dopaminergic nerve loss. In addition to dopaminergic imaging, serotonin transporter and N-methyl-D-aspartate (NMDA) receptor probes are increasingly used as research tools to better understand the complexity of neurotransmitter dysregulation in PD. Non-invasive quantification of neuroinflammatory processes is mainly conducted by targeting the translocator protein 18 kDa (TSPO) on activated microglia using established imaging agents. Despite the overwhelming involvement of the brain and brainstem, the pathophysiology of PD is not restricted to the central nervous system (CNS). In fact, PD also affects various peripheral organs such as the heart and gastrointestinal tract - primarily via autonomic dysfunction. As such, research into peripheral biomarkers has taken advantage of cardiac autonomic denervation in PD, allowing the differential diagnosis between PD and multiple system atrophy with probes that visualize sympathetic nerve terminals in the myocardium. Further, α-synuclein has recently gained attention as a potential peripheral biomarker in PD. This review discusses breakthrough discoveries that have led to the contemporary molecular concepts of PD pathophysiology and how they can be harnessed to develop effective imaging probes and therapeutic agents. Further, we will shed light on potential future trends, thereby focusing on potential novel diagnostic tracers and disease-modifying therapeutic interventions.

Differences in Striatal Metabolism in [18F]FDG PET in Parkinson's Disease and Atypical Parkinsonism

Neurodegenerative parkinsonisms affect mainly cognitive and motor functions and are syndromes of overlapping symptoms and clinical manifestations such as tremor, rigidness, and bradykinesia. These include idiopathic Parkinson's disease (PD) and the atypical parkinsonisms, namely progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), multiple system atrophy (MSA) and dementia with Lewy body (DLB). Differences in the striatal metabolism among these syndromes are evaluated using [¹⁸F]FDG PET, caused by alterations to the dopaminergic activity and neuronal loss. A study cohort of three patients with PD, 29 with atypical parkinsonism (10 PSP, 6 CBD, 2 MSA, 7 DLB, and 4 non-classifiable), and a control group of 25 patients with normal striatal metabolism is available. Standardized uptake value ratios (SUVR) are extracted from the striatum, and the caudate and the putamen separately. SUVRs are compared among the study groups. In addition, hemispherical and caudate-putamen differences are evaluated in atypical parkinsonisms. Striatal hypermetabolism is detected in patients with PD, while atypical parkinsonisms show hypometabolism, compared to the control group. Hemispherical differences are observed in CBD, MSA and DLB, with the latter also showing statistically significant caudate-putamen asymmetry (p = 0.018). These results indicate disease-specific metabolic uptake patterns in the striatum that can support the differential diagnosis.

Recent Advances of NIR-II Emissive Semiconducting Polymer Dots for In Vivo Tumor Fluorescence Imaging and Theranostics

Accurate diagnosis and treatment of tumors, one of the top global health problems, has always been the research focus of scientists and doctors. Near-infrared (NIR) emissive semiconducting polymers dots (Pdots) have demonstrated bright prospects in field of in vivo tumor fluorescence imaging owing to some of their intrinsic advantages, including good water-dispersibility, facile surface-functionalization, easily tunable optical properties, and good biocompatibility. During recent years, much effort has been devoted to developing Pdots with emission bands located in the second near-infrared (NIR-II, 1000-1700 nm) region, which hold great advantages of higher spatial resolution, better signal-to-background ratios (SBR), and deeper tissue penetration for solid-tumor imaging in comparison with the visible region (400-680 nm) and the first near-infrared (NIR-I, 680-900 nm) window, by virtue of the reduced tissue autofluorescence, minimal photon scattering, and low photon absorption. In this review, we mainly summarize the latest advances of NIR-II emissive semiconducting Pdots for in vivo tumor fluorescence imaging, including molecular engineering to improve the fluorescence quantum yields and surface functionalization to elevate the tumor-targeting capability. We also present several NIR-II theranostic Pdots used for integrated tumor fluorescence diagnosis and photothermal/photodynamic therapy. Finally, we give our perspectives on future developments in this field.

Molecular Imaging in Parkinsonian Disorders—What’s New and Hot?

Highlights

Abstract

Neurodegenerative parkinsonian disorders are characterized by a great diversity of clinical symptoms and underlying neuropathology, yet differential diagnosis during lifetime remains probabilistic. Molecular imaging is a powerful method to detect pathological changes in vivo on a cellular and molecular level with high specificity. Thereby, molecular imaging enables to investigate functional changes and pathological hallmarks in neurodegenerative disorders, thus allowing to better differentiate between different forms of degenerative parkinsonism, improve the accuracy of the clinical diagnosis and disentangle the pathophysiology of disease-related symptoms. The past decade led to significant progress in the field of molecular imaging, including the development of multiple new and promising radioactive tracers for single photon emission computed tomography (SPECT) and positron emission tomography (PET) as well as novel analytical methods. Here, we review the most recent advances in molecular imaging for the diagnosis, prognosis, and mechanistic understanding of parkinsonian disorders. First, advances in imaging of neurotransmission abnormalities, metabolism, synaptic density, inflammation, and pathological protein aggregation are reviewed, highlighting our renewed understanding regarding the multiplicity of neurodegenerative processes involved in parkinsonian disorders. Consequently, we review the role of molecular imaging in the context of disease-modifying interventions to follow neurodegeneration, ensure stratification, and target engagement in clinical trials.

Plasma α-synuclein and phosphorylated tau 181 as a diagnostic biomarker panel for de novo Parkinson's Disease

The use of a diagnostic panel comprising multiple biomarkers has the potential to accurately diagnose Parkinson’s disease (PD). However, a panel consisting solely of plasma biomarkers to diagnose PD is not available. This study aimed to examine the diagnostic ability of plasma biomarker panels for de novo PD using novel digital ultrasensitive immunoassay technology. We recruited 45 patients with de novo PD and 20 healthy controls (HCs). The concentrations of plasma α‐synuclein (α‐syn), amyloid β‐42 (Aβ42), Aβ40, phosphorylated tau 181 (p‐tau181), neurofilament light (NFL), and glial fibrillary acidic protein (GFAP) were quantified using the ultrasensitive single molecule array (Simoa) platform. Patients with de novo PD had higher plasma levels of α‐syn and p‐tau181 than HCs, adjusting for age and sex. Plasma levels of α‐syn and p‐tau181 were positively correlated in de novo PD patients. Higher plasma α‐syn levels were significantly associated with worse Unified Parkinson’s Disease Rating Scale (UPDRS) Part III motor scores, modified Hoehn and Yahr (H‐Y) stages, and increased risk of PD with mild cognitive impairment (PD‐MCI). Higher plasma p‐tau181 concentrations were linked to worse H‐Y stages. The diagnostic panel using plasma α‐syn and p‐tau181, combined with age and sex, showed good performance in discriminating de novo PD patients from HCs (area under the curve = 0.806). These findings suggest that plasma α‐syn and p‐tau181 together may be a promising diagnostic biomarker panel for de novo PD patients.

Preparation of a gold@europium-based coordination polymer nanocomposite with excellent photothermal properties and its potential for four-mode imaging

A nanocomposite was synthesized by replacing the toxic CTAB on the surface of GNRs with a europium-based hyaluronic acid coordination polymer. The nanocomposite exhibits excellent photothermal performance and also has potential for four-mode imaging.

Dopamine transporter (DAT) imaging in Parkinson's disease and related disorders

This review gives an insight into the beginnings of dopamine transporter (DAT) imaging in the early 1990s, focussing on single photon emission tomography (SPECT). The development of the method and its consolidation as a now widely used clinical tool is described. The role of DAT-SPECT in the diagnosis and differential diagnosis of PD, atypical parkinsonian syndromes and several other different neurological disorders is reviewed. Finally the clinical research using DAT-SPECT as a biomarker for the progression of PD, for the detection of a preclinical dopaminergic lesion and its correlation with neuropathological findings is outlined.

EANM procedure guidelines for brain PET imaging using [18F]FDG, version 3

The present procedural guidelines summarize the current views of the EANM Neuro-Imaging Committee (NIC). The purpose of these guidelines is to assist nuclear medicine practitioners in making recommendations, performing, interpreting, and reporting results of [¹⁸F]FDG-PET imaging of the brain. The aim is to help achieve a high-quality standard of [¹⁸F]FDG brain imaging and to further increase the diagnostic impact of this technique in neurological, neurosurgical, and psychiatric practice. The present document replaces a former version of the guidelines that have been published in 2009. These new guidelines include an update in the light of advances in PET technology such as the introduction of digital PET and hybrid PET/MR systems, advances in individual PET semiquantitative analysis, and current broadening clinical indications (e.g., for encephalitis and brain lymphoma). Further insight has also become available about hyperglycemia effects in patients who undergo brain [¹⁸F]FDG-PET. Accordingly, the patient preparation procedure has been updated. Finally, most typical brain patterns of metabolic changes are summarized for neurodegenerative diseases. The present guidelines are specifically intended to present information related to the European practice. The information provided should be taken in the context of local conditions and regulations.