Evaluation of both perfusion and atrophy in multiple system atrophy of the cerebellar type using brain SPECT alone

BACKGROUND: Partial volume effects in atrophied areas should be taken into account when interpreting brain perfusion single photon emission computed tomography (SPECT) images of neurodegenerative diseases. To evaluate both perfusion and atrophy using brain SPECT alone, we developed a new technique applying tensor-based morphometry (TBM) to SPECT. METHODS: After linear spatial normalization of brain perfusion SPECT using (99m)Tc-ethyl cysteinate dimer ((99m)Tc-ECD) to a Talairach space, high-dimension-warping was done using an original (99m)Tc-ECD template. Contraction map images calculated from Jacobian determinants and spatially normalized SPECT images using this high-dimension-warping were compared using statistical parametric mapping (SPM2) between two groups of 16 multiple system atrophy of the cerebellar type (MSA-C) patients and 73 age-matched normal controls. This comparison was also performed in conventionally warped SPECT images. RESULTS: SPM2 demonstrated statistically significant contraction indicating local atrophy and decreased perfusion in the whole cerebellum and pons of MSA-C patients as compared to normal controls. Higher significance for decreased perfusion in these areas was obtained in high-dimension-warping than in conventional warping, possibly due to sufficient spatial normalization to a (99m)Tc-ECD template in high-dimensional warping of severely atrophied cerebellum and pons. In the present high-dimension-warping, modification of tracer activity remained within 3% of the original tracer distribution. CONCLUSIONS: The present new technique applying TBM to brain SPECT provides information on both perfusion and atrophy at the same time thereby enhancing the role of brain perfusion SPEC

Consensus Paper: Radiological Biomarkers of Cerebellar Diseases

Hereditary and sporadic cerebellar ataxias represent a vast and still growing group of diseases whose diagnosis and differentiation cannot only rely on clinical evaluation. Brain imaging including magnetic resonance (MR) and nuclear medicine techniques allows for characterization of structural and functional abnormalities underlying symptomatic ataxias. These methods thus constitute a potential source of radiological biomarkers, which could be used to identify these diseases and differentiate subgroups of them, and to assess their severity and their evolution. Such biomarkers mainly comprise qualitative and quantitative data obtained from MR including proton spectroscopy, diffusion imaging, tractography, voxel-based morphometry, functional imaging during task execution or in a resting state, and from SPETC and PET with several radiotracers. In the current article, we aim to illustrate briefly some applications of these neuroimaging tools to evaluation of cerebellar disorders such as inherited cerebellar ataxia, fetal developmental malformations, and immune-mediated cerebellar diseases and of neurodegenerative or early-developing diseases, such as dementia and autism in which cerebellar involvement is an emerging feature. Although these radiological biomarkers appear promising and helpful to better understand ataxia-related anatomical and physiological impairments, to date, very few of them have turned out to be specific for a given ataxia with atrophy of the cerebellar system being the main and the most usual alteration being observed. Consequently, much remains to be done to establish sensitivity, specificity, and reproducibility of available MR and nuclear medicine features as diagnostic, progression and surrogate biomarkers in clinical routine

Role of Neuroimaging on Differentiation of Parkinson’s Disease and Its Related Diseases

An accurate diagnosis of Parkinson’s disease (PD) is a prerequisite for therapeutic management. In spite of recent advances in the diagnosis of parkinsonian disorders, PD is misdiagnosed in between 6 and 25% of patients, even in specialized movement disorder centers. Although the gold standard for the diagnosis of PD is a neuropathological assessment, neuroimaging has been playing an important role in the differential diagnosis of PD and is used for clinical diagnostic criteria. In clinical practice, differential diagnoses of PD include atypical parkinsonian syndromes such as dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, caused by a striatal dopamine deficiency following nigrostrial degeneration. PD may also be mimicked by syndromes not associated with a striatal dopamine deficiency such as essential tremor, drug-induced parkinsonism, and vascular parkinsonism. Moreover, difficulties are associated with the clinical differentiation of patients with parkinsonism from those with Alzheimer’s disease. In this review, we summarize the typical imaging findings of PD and its related diseases described above using morphological imaging modalities (conventional MR imaging and neuromelanin MR imaging) and functional imaging modalities (99mTc-ethyl cysteinate dimer perfusion single photon emission computed tomography, 123I-metaiodobenzylguanidine myocardial scintigraphy, and 123I-FP-CIT dopamine transporter single photon emission computed tomography) that are clinically available in most hospitals. We also attempt to provide a diagnostic approach for the differential diagnosis of PD and its related diseases in clinical practice

Bildgebende Veränderungen bei Autoimmunenzephalitis: systematischer Review und Meta-Analyse

Considering the severity and the rapid progress of autoimmune encephalitides, an early diagnosis is essential. To facilitate diagnosis, we aim to create a deeper understanding of the condition. Therefore, we systematically review imaging alterations occurring in different subtypes of auto- immune encephalitis. Our goal is to find patterns in these changes with possible relation to the patients’ clinical features. Here, we focus on autoimmune conditions caused by autoantibodies targeting neuronal cell surface structures, as these show a significantly better outcome after early diagnosis and treatment. We first defined a search query and set up inclusion/exclusion criteria for the articles. We used PubMed and Google Scholar for articles published from 2007-2021, with a dedicated query for each autoantibody. The reports were summarized in tables regarding the neuroimaging findings in relation to their timing, the patients’ demographics, and symptoms. We then visualized our results graphically. In a meta-analysis with the MetaXL statistics package, we derived a hetero- geneity analysis and assessed the risk of bias to obtain a pooled summary. Of 1,748 articles identified, 177 were included in our meta-analysis. This translates into a total of 5,050 patients. The pooled prevalence of MRI changes for each autoimmune encephalitis subtype varies from 0.11 (CI: 0-0.33) for igLON5 disease to 0.86 (CI: 0.7-0.97) for AMPAR encephalitis. We find that nearly all heterogeneity values obtained in our pooling analysis are still high and show a considerable variation (I2 0-90 %). Our results imply that pooling all antibodies in summa- rized studies is still challenging. This could be due to several factors, such as the diverse under- lying pathologies or the small number of patients currently included in the studies. However, our results confirm the findings of prior, smaller meta-analyses and further enhance their results. When pooling the prevalence of MRI changes over all subtypes collectively, the statistical findings of our meta-analysis are in excellent agreement with the results in the most recently published studies.11 To explore whether the heterogeneity is lower when considering a different subset of the imaging data, we analyzed the MRIs of the post-acute disease stage. This was only feasible for the two encephalitis subtypes with the most published cases (NMDAR and LGI1). For LGI1 encephalitis, we found similar heterogeneity between the studies reporting acute and post-acute MRI changes (I2 76 % vs. 74 %), while for NMDA, encephalitis I2 was significantly lower (I2 73 % vs. 61 %). The encephalitis subtype where we found the most significant result was anti-GABAb encephalitis. Here we detected a high pooled prevalence of MRI changes (0.63) associated with a low hetero- geneity (I2 19 %) while including a larger number of studies (12).Aufgrund des Schweregrads und der raschen Progredienz der Autoimmunenzephalitiden ist eine frühzeitige Diagnose entscheidend. Um die Diagnose zu erleichtern, möchten wir ein tieferes Verständnis der Erkrankung schaffen. Daher untersuchen wir systematisch die bei den Autoim- munenzephalitiden auftretenden bildgebende Veränderungen. Unser Ziel ist es, Muster in den Veränderungen zu finden, die mit den klinischen Merkmalen der Patienten assoziiert sind. Wir konzentrieren uns hier auf Autoimmunenzephalitiden, die durch neuronale Zelloberflächenanti- körper verursacht werden. Diese weisen bei einer frühzeitigen Diagnose und Therapie einen deutlich besseren Verlauf auf. Zunächst definierten wir eine Suchanfrage und legten Aus-/Einschlusskriterien für die Artikel fest. Für jeden Autoantikörper wurde eine dedizierte Abfrage in PubMed und Google Scholar ange- wendet auf Artikel, die zwischen 2007-2021 veröffentlicht wurden. Die Artikel wurden in Tabellen zusammengefasst, in denen die Befunde der neurologischen Bildgebung in Bezug auf den Zeit- punkt, die demografischen Merkmale und Symptome der Patienten dargestellt wurden. Unsere Ergebnisse haben wir in mit FSLeyes erstellten Grafiken visualisiert. In einer Meta-Analyse mit dem Statistikpaket MetaXL poolten wir die Ergebnisse, führten eine Heterogenitätsanalyse durch und bewerteten das Risk of Bias. Von 1.748 identifizierten Artikeln wurden 177 ≙ 5050 Patienten in unsere Meta-Analyse aufge- nommen. Die gepoolte Prävalenz von MRT-Veränderungen für die einzelnen Subtypen schwankt zwischen 0,11 (CI: 0-0,33) für die igLON5-Erkrankung und 0,86 (CI: 0,7-0,97) für die AMPAR- Enzephalitis. Die in unserer Pooling-Analyse ermittelten Heterogenitätswerte variieren ebenfalls, sind jedoch meist hoch (I2 0-90 %). Daraus zeigt sich, dass es schwierig ist, die Antikörper in Studien zusammenzufassen. Dies könnte z.B. auf die unterschiedlichen zugrundeliegenden Pa- thologien und häufigen Einzelfallstudien zurückzuführen sein. Unsere Ergebnisse bestätigen je- doch die Ergebnisse früherer, kleinerer Meta-Analysen. Bei Berücksichtigung aller Autoantikörper gemeinsam, stimmen unsere statistischen Ergebnisse für die gepoolte Prävalenz von MRT Ver- änderungen hervorragend mit zuletzt veröffentlichten Studien1 überein1. Um zu untersuchen, ob die Heterogenität sinkt bei Betrachten einer Subgruppe, haben wir MRT Veränderungen des postakuten Krankheitsstadiums analysiert. Dies war nur für die beiden Sub- typen mit den meisten veröffentlichten Fällen möglich. Bei der LGI1-Enzephalitis fanden wir eine ähnliche Heterogenität zwischen den Studien des akuten und postakuten Zustands (I2 76 % vs. 74 %), bei NMDA-Enzephalitis sankt I2 deutlicher in der postakuten Analyse (I2 73 % vs. 61%). Für Anti-GABAb-Enzephalitis fanden wir das signifikanteste Ergebnis. Hier stellten wir eine hohe gepoolte Prävalenz von MRT-Veränderungen (0,63) fest, bei einer geringen Heterogenität (I2 19 %) und Einbezug einer größeren Anzahl von Studien (12)

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. 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

Effects of dance therapy on balance, gait and neuro-psychological performances in patients with Parkinson's disease and postural instability

Postural Instability (PI) is a core feature of Parkinson’s Disease (PD) and a major cause of falls and disabilities. Impairment of executive functions has been called as an aggravating factor on motor performances. Dance therapy has been shown effective for improving gait and has been suggested as an alternative rehabilitative method. To evaluate gait performance, spatial-temporal (S-T) gait parameters and cognitive performances in a cohort of patients with PD and PI modifications in balance after a cycle of dance therapy

Neuroimaging in Dementia

Dementia is a common illness with an incidence that is rising as the aged population increases. There are a number of neurodegenerative diseases that cause dementia, including Alzheimer’s disease, dementia with Lewy bodies, and frontotemporal dementia, which is subdivided into the behavioral variant, the semantic variant, and nonfluent variant. Numerous other neurodegenerative illnesses have an associated dementia, including corticobasal degeneration, Creutzfeldt–Jakob disease, Huntington’s disease, progressive supranuclear palsy, multiple system atrophy, Parkinson’s disease dementia, and amyotrophic lateral sclerosis. Vascular dementia and AIDS dementia are secondary dementias. Diagnostic criteria have relied on a constellation of symptoms, but the definite diagnosis remains a pathologic one. As treatments become available and target specific molecular abnormalities, differentiating amongst the various primary dementias early on becomes essential. The role of imaging in dementia has traditionally been directed at ruling out treatable and reversible etiologies and not to use imaging to better understand the pathophysiology of the different dementias. Different brain imaging techniques allow the examination of the structure, biochemistry, metabolic state, and functional capacity of the brain. All of the major neurodegenerative disorders have relatively specific imaging findings that can be identified. New imaging techniques carry the hope of revolutionizing the diagnosis of neurodegenerative disease so as to obtain a complete molecular, structural, and metabolic characterization, which could be used to improve diagnosis and to stage each patient and follow disease progression and response to treatment. Structural and functional imaging modalities contribute to the diagnosis and understanding of the different dementias

Neuroimaging in Dementia: More than Typical Alzheimer Disease

Alzheimer disease (AD) is the most common cause of dementia. The prevailing theory of the underlying pathology assumes amyloid accumulation followed by tau protein aggregation and neurodegeneration. However, the current antiamyloid and antitau treatments show only variable clinical efficacy. Three relevant points are important for the radiologic assessment of dementia. First, besides various dementing disorders (including AD, frontotemporal dementia, and dementia with Lewy bodies), clinical variants and imaging subtypes of AD include both typical and atypical AD. Second, atypical AD has overlapping radiologic and clinical findings with other disorders. Third, the diagnostic process should consider mixed pathologies in neurodegeneration, especially concurrent cerebrovascular disease, which is frequent in older age. Neuronal loss is often present at, or even before, the onset of cognitive decline. Thus, for effective emerging treatments, early diagnosis before the onset of clinical symptoms is essential to slow down or stop subsequent neuronal loss, requiring molecular imaging or plasma biomarkers. Neuroimaging, particularly MRI, provides multiple imaging parameters for neurodegenerative and cerebrovascular disease. With emerging treatments for AD, it is increasingly important to recognize AD variants and other disorders that mimic AD. Describing the individual composition of neurodegenerative and cerebrovascular disease markers while considering overlapping and mixed diseases is necessary to better understand AD and develop efficient individualized therapies