A comparison of advanced semi-quantitative amyloid PET analysis methods.

PURPOSE: To date, there is no consensus on how to semi-quantitatively assess brain amyloid PET. Some approaches use late acquisition alone (e.g., ELBA, based on radiomic features), others integrate the early scan (e.g., TDr, which targets the area of maximum perfusion) and structural imaging (e.g., WMR, that compares kinetic behaviour of white and grey matter, or SI based on the kinetic characteristics of the grey matter alone). In this study SUVr, ELBA, TDr, WMR, and SI were compared. The latter - the most complete one - provided the reference measure for amyloid burden allowing to assess the efficacy and feasibility in clinical setting of the other approaches. METHODS: We used data from 85 patients (aged 44-87) who underwent dual time-point PET/MRI acquisitions. The correlations with SI were computed and the methods compared with the visual assessment. Assuming SUVr, ELBA, TDr, and WMR to be independent measures, we linearly combined them to obtain more robust indices. Finally, we investigated possible associations between each quantifier and age in amyloid-negative patients. RESULTS: Each quantifier exhibited excellent agreement with visual assessment and strong correlation with SI (average AUC = 0.99, ρ = 0.91). Exceptions to this were observed for subcortical regions with ELBA and WMR (ρELBA = 0.44, ρWMR = 0.70). The linear combinations showed better performances than the individual methods. Significant associations were observed between TDr, WMR, SI, and age in amyloid-negative patients (p < 0.05). CONCLUSION: Among the other methods, TDr came closest to the reference with less implementation complexity. Moreover, this study suggests that combining independent approaches gives better results than the individual procedure, so efforts should focus on multi-classifier systems for amyloid PET. Finally, the ability of techniques integrating blood perfusion to depict age-related variations in amyloid load in amyloid-negative subjects demonstrates the goodness of the estimate.

The contribution of beta-amyloid to dementia in Lewy body diseases: a 1-year follow-up study.

Dementia in Lewy Body Diseases (Parkinson's disease and dementia with Lewy Bodies) affects progression of disabilities, quality of life and well-being. Understanding its pathogenetic mechanisms is critical to properly implement disease-modifying strategies. It has been hypothesized that synuclein- and amyloid-pathology act synergistically aggravating cognitive decline in elderly patients but their precise contribution to dementia is debated. In this study, we aimed at exploring if presence of amyloid deposits influences clinical, cognitive and neuroanatomical correlates of mental decline in a cohort of 40 Parkinson's disease patients with normal cognition (n = 5), mild cognitive impairment (n = 22), and dementia (n = 13) as well as in Dementia with Lewy Bodies (n = 10). Patients underwent simultaneous 3 T PET/MRI with [18F]-flutemetamol and were assessed with an extensive baseline motor and neuropsychological examination, which allowed level II diagnosis of mild cognitive impairment and dementia. The role of amyloid positivity on each cognitive domain, and on the rate of conversion to dementia at 1-year follow-up was explored. A Kaplan Meier and the Log Rank (Mantel-Cox) test were used to assess the pairwise differences in time-to-develop dementia in Parkinson's disease patients with and without significant amyloidosis. Furthermore, the presence of an Alzheimer's dementia-like morphological pattern was evaluated using visual and automated assessment of T1-weighted and T2-weighted MRI images. We observed similar percentage of amyloid deposits in Parkinson's disease dementia and dementia with Lewy Bodies cohorts (50% in each group) with an overall prevalence of 34% of significant amyloid depositions in Lewy Body Diseases. PET amyloid positivity was associated with worse global cognition (Montreal Cognitive Assessment and Mini Mental State Examination), executive and language difficulties. At 12-month follow-up, amyloid positive Parkinson's disease patients were more likely to have become demented than those without amyloidosis. Moreover, there was no difference in the presence of an Alzheimer's disease-like atrophy pattern and in vascular load (at Fazekas scale) between Lewy Body Diseases with and without significant amyloid deposits. Our findings suggest that in Lewy Body Diseases, amyloid deposition enhances cognitive deficits, particularly attention-executive and language dysfunctions. However, the large number of patients without significant amyloid deposits among our cognitively impaired patients indicates that synuclein pathology itself plays a critical role in the development of dementia in Lewy Body Diseases.

Emerging topics and practical aspects for an appropriate use of amyloid PET in the current Italian context.

In May 2017 some representatives of the Italian nuclear medicine and neurological communities spontaneously met to discuss the issues emerged during the first two years of routine application of amyloid PET with fluorinated radiopharmaceuticals in the real world. The limitations of a binary classification of scans, the possibility to obtain early images as a surrogate marker of regional cerebral bloos flow, the need for (semi-)quantification and, thus, the opportunity of ranking brain amyloidosis, the correlation with Aß42 levels in the cerebrospinal fluid, the occurrence and biological meaning of uncertain/boderline scans, the issue of incidental amyloidosis, the technical pittfalls leading to false negative/positive results, the position of the tool in the diagnostic flow-chart in the national reality, are the main topics that have been discussed. Also, a card to justify the examination to be filled by the dementia specialist and a card for the nuclear medicine physician to report the exam in detail have been approved and are available in the web, which should facilitate the creation of a national register, as previewed by the 2015 intersocietal recommendation on the use of amyloid PET in Italy. The content of this discussion could stimulate both public institutions and companies to support further research on these topics.

Long-term preclinical magnetic resonance imaging alterations in sporadic Creutzfeldt-Jakob disease.

An asymptomatic 74-year-old woman, on follow-up for a carotid body tumor, showed magnetic resonance imaging (MRI) focal restricted diffusion confined to the left temporal and occipital cortices. Thirteen months later, diffusion-weighted images revealed a bilateral cortical ribbon sign involving all lobes. After 1 month, the patient developed gait instability and cognitive decline rapidly evolving to severe dementia and death within 3 months. Prion protein gene sequence, molecular, and neuropathological studies confirmed the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) MM1 subtype. Here we show the kinetics of MRI changes and prion spreading in preclinical sCJD MM1. Ann Neurol 2016;80:629-632.

Subcortical mapping of calculation processing in the right parietal lobe.

Preservation of calculation processing in brain surgery is crucial for patients' quality of life. Over the last decade, surgical electrostimulation was used to identify and preserve the cortical areas involved in such processing. Conversely, subcortical connectivity among different areas implicated in this function remains unclear, and the role of surgery in this domain has not been explored so far. The authors present the first 2 cases in which the subcortical functional sites involved in calculation were identified during right parietal lobe surgery. Two patients affected by a glioma located in the right parietal lobe underwent surgery with the aid of MRI neuronavigation. No calculation deficits were detected during preoperative assessment. Cortical and subcortical mapping were performed using a bipolar stimulator. The current intensity was determined by progressively increasing the amplitude by 0.5-mA increments (from a baseline of 1 mA) until a sensorimotor response was elicited. Then, addition and multiplication calculation tasks were administered. Corticectomy was performed according to both the MRI neuronavigation data and the functional findings obtained through cortical mapping. Direct subcortical electrostimulation was repeatedly performed during tumor resection. Subcortical functional sites for multiplication and addition were detected in both patients. Electrostimulation interfered with calculation processing during cortical mapping as well. Functional sites were spared during tumor removal. The postoperative course was uneventful, and calculation processing was preserved. Postoperative MRI showed complete resection of the tumor. The present preliminary study shows for the first time how functional mapping can be a promising method to intraoperatively identify the subcortical functional sites involved in calculation processing. This report therefore supports direct electrical stimulation as a promising tool to improve the current knowledge on calculation processing connectivity.

Impulse control disorders in frontotemporal dementia: spectrum of symptoms and response to treatment.

OBJECTIVE: To describe a patient with behavioral variant frontotemporal dementia (bvFTD) presenting with impulse control disorders (ICDs) which responded to fluvoxamine and topiramate. CASE REPORT: A 64-year-old woman was affected by several ICDs. At disease onset, she suffered from impulsive smoking and overeating which caused a body weight increase of 20 kg in 6 months. Later on she manifested binge-eating behavior and skin-picking compulsion. Presence of progressive frontal cognitive impairment (Mini Mental State Examination 24/30) and evidence of hypoperfusion of the anterior cingulate and dorsolateral frontal cortex with brain single-photon emission computed tomography scan contributed to the diagnosis of bvFTD. Use of combination treatment with selective serotonin reuptake inhibitor drugs and topiramate improved all these symptoms. CONCLUSION: This case extends the clinical phenotype of repetitive and compulsive habits in bvFTD to encompass symptoms suggestive of ICDs. It is proposed that fluvoxamine and topiramate may be considered as treatment options in these conditions.

Improving the knowledge of amyotrophic lateral sclerosis genetics: novel SOD1 and FUS variants.

Amyotrophic lateral sclerosis (ALS) is as an adult-onset neurodegenerative disorder involving both upper and lower motor neurons. About 5% of all cases exhibit signs of frontotemporal degeneration (FTD). We established the mutation frequency of C9ORF72, SOD1, TARDBP, and FUS genes in 307 patients with sporadic ALS, 46 patients with familial ALS (FALS), and 73 patients affected with FTD, all originating from the northeastern part of Italy. C9ORF72 pathogenic expansion was found on 22% of familial ALS, 5% of sporadic ALS, and 14% of FTD patients, resulting the most frequently genetic determinant in our cohort. Sequence analysis of ALS cohort identified 2 novel variants on SOD1 (p.Glu41Gly) and FUS (p.Gly496Glyfs*31). Interestingly, the single base deletion on FUS was observed in an homozygous state, suggesting a recessive pattern of inheritance. No point mutations were identified on FTD cohort. Although useful to direct genetic testing, this study results expand the current knowledge of ALS genetics.

Case series evidence for improvement of executive functions after late cranioplasty.

OBJECTIVE: Craniectomy, used to relieve refractory intracranial pressure in traumatic brain injury (TBI), may cause cognitive deficits which could be improved by skull breach repair. This paper studied whether late cranioplasty improves a specific pattern of cognitive functions. DESIGN: A case series of five TBI patients with craniectomy undergoing late cranioplasty (median interval time: 14 months, range: 12-36). METHODS: Longitudinal neuropsychological and brain MRI assessments 1 week before cranioplasty and 3 months later. RESULTS: After cranioplasty, mean score of the verbal fluency test improved compared to pre-cranioplasty (p = 0.02). Similarly, significant improvements after cranioplasty were observed in other tests scores exploring executive functions, such as working memory (p = 0.03) and speed of attention (p = 0.04), independently from the size and site of cranioplasty. CONCLUSIONS: The cognitive improvement induced by cranioplasty, even when performed after a long interval from craniectomy, may be due to the restoration of physiological cerebrospinal fluid circulation which, in turn, allows an efficient brain volume transmission signal circulation. The restoration of this essential way of signal communication seems to affect large-scale neuronal networks responsible for the executive functions.

Pituitary tumor apoplexy presenting as infective meningoencephalitis.

We report on a case of a 80-year-old man who developed progressive drowsiness with headache, fever and signs of meningeal irritation 2 days after a head trauma. Suspecting an infective meningoencephalitis, the patient was treated with wide spectrum antibiotic and antiviral therapy. Brain CT scan revealed a previously unknown pituitary expansive lesion. A brain MRI study confirmed the presence of an intrasellar lesion, which presented remarkable contrast ring enhancement, and showed non-specific inflammatory tissue on the clivus, possibly responsible of the clinical features of sterile meningitis. A biopsy proven diagnosis of pituitary apoplexy was made. This case highlights MRI as an important investigation for earlier recognition of pituitary apoplexy that can present with a clinical picture resembling an infective meningoencephalitis.

Syringomyelia associated with Chiari I malformation.

An 18-year-old man with progressive paraparesis, thermal hypoesthesia, sweating abnormalities, bladder dysfunction, severe orthostatic hypotension, bilateral Babinski sign, underwent a brain MRI scan that showed downward displacement of cerebellar tonsils through the foramen magnum, consistent with Chiari I malformation, compression of the brainstem-spinal cord junction, and C1-D11 syringomyelia (6.5 mm diameter at C2 level) consistent with Chiari I syndrome. Suboccipital craniectomy and duraplasty were performed. A C2 partial laminectomy and ablation of posterior arch of the atlas was performed. MRI scans 4 days and 1 month after surgery showed a dramatic syringomyelia reabsorption (2.5 and 1 mm, respectively) associated with complete clinical recovery.