PurposePositron emission tomography (PET) imaging of brain amyloid load has been suggested as a core biomarker for Alzheimer’s disease (AD). The aim of this study was to test the feasibility of using PET imaging with 18F-AV-45 (florbetapir) in a routine clinical environment to differentiate between patients with mild to moderate AD and mild cognitive impairment (MCI) from normal healthy controls (HC).MethodsIn this study, 46 subjects (20 men and 26 women, mean age of 69.0 ± 7.6 years), including 13 with AD, 12 with MCI and 21 HC subjects, were enrolled from three academic memory clinics. PET images were acquired over a 10-min period 50 min after injection of florbetapir (mean ± SD of radioactivity injected, 259 ± 57 MBq). PET images were assessed visually by two individuals blinded to any clinical information and quantitatively via the standard uptake value ratio (SUVr) in the specific regions of interest, which were defined in relation to the cerebellum as the reference region.ResultsThe mean values of SUVr were higher in AD patients (median 1.20, Q1-Q3 1.16-1.30) than in HC subjects (median 1.05, Q1-Q3 1.04-1.08; p = 0.0001) in the overall cortex and all cortical regions (precuneus, anterior and posterior cingulate, and frontal median, temporal, parietal and occipital cortex). The MCI subjects also showed a higher uptake of florbetapir in the posterior cingulate cortex (median 1.06, Q1-Q3 0.97-1.28) compared with HC subjects (median 0.95, Q1-Q3 0.82-1.02; p = 0.03). Qualitative visual assessment of the PET scans showed a sensitivity of 84.6% (95% CI 0.55–0.98) and a specificity of 38.1% (95% CI 0.18–0.62) for discriminating AD patients from HC subjects; however, the quantitative assessment of the global cortex SUVr showed a sensitivity of 92.3% and specificity of 90.5% with a cut-off value of 1.122 (area under the curve 0.894).ConclusionThese preliminary results suggest that PET with florbetapir is a safe and suitable biomarker for AD that can be used routinely in a clinical environment. However, the low specificity of the visual PET scan assessment could be improved by the use of specific training and automatic or semiautomatic quantification tools.

There is growing evidence of activated microglia and inflammatory processes in the cerebral cortex in amyotrophic lateral sclerosis (ALS). Activated microglia is characterized by increased expression of the 18 kDa translocator protein (TSPO) in the brain and may be a useful biomarker of inflammation. In this study, we evaluated neuroinflammation in ALS patients using a radioligand of TSPO, 18F-DPA-714. Ten patients with probable or definite ALS (all right-handed, without dementia, and untreated by riluzole or other medication that might bias the binding on the TSPO), were enrolled prospectively and eight healthy controls matched for age underwent a PET study. Comparison of the distribution volume ratios between both groups were performed using a Mann-Whitney’s test. Significant increase of distribution of volume ratios values corresponding to microglial activation was found in the ALS sample in primary motor, supplementary motor and temporal cortex (p = 0.009, p = 0.001 and p = 0.004, respectively). These results suggested that the cortical uptake of 18F-DPA-714 was increased in ALS patients during the “time of diagnosis” phase of the disease. This finding might improve our understanding of the pathophysiology of ALS and might be a surrogate marker of efficacy of treatment on microglial activation.

The radiologic diagnosis of cavernous sinus invasion by pituitary adenoma remains difficult, but the above-mentioned criteria may be of assistance.

In young healthy adults, ultrasonography appeared to be a reliable tool to assess the diameter of the subglottic upper airway.

BackgroundCerebral stroke is a severe and frequent condition that requires rapid and reliable diagnosis. If administered shortly after the first symptoms manifest themselves, IV thrombolysis has been shown to increase the functional prognosis by restoring brain reperfusion. However, a better understanding of the pathophysiology of stroke should help to identify potential new therapeutic targets. Stroke is known to induce an inflammatory brain reaction that involves overexpression of the 18-kDa translocator protein (TSPO) in glial cells and infiltrated leukocytes, which can be visualised by positron emission tomography (PET). We aimed to evaluate post-stroke neuroinflammation using the PET TSPO radioligand 18 F-DPA-714.MethodsNine patients underwent 18 F-DPA-714 PET and magnetic resonance imaging (MRI) between 8 and 18 days after the ictus. Co-registration of MRI and PET images was used to define three volumes of interest (VOIs): core infarction, contralateral region, and cerebellum ipsilateral to the stroke lesion. Time activity curves were obtained from each VOI, and ratios of mean and maximum activities between the VOIs were calculated.ResultsWe observed an increased uptake of 18 F-DPA-714 co-localised with the infarct tissue and extension beyond the region corresponding to the damage in the blood brain barrier. No correlation was identified between 18 F-DPA-714 uptake and infarct volume. 18 F-DPA-714 uptake in ischemic lesion (mainly associated with TSPO expression in the infarct area and in the surrounding neighbourhood) slowly decreased from 10 min pi to the end of the PET acquisition, remaining higher than that in both contralateral region and ipsilateral cerebellum.ConclusionOur results show that 18 F-DPA-714 uptake after acute ischemia is mainly associated with TSPO expression in the infarct area and in the surrounding neighbourhood. We also demonstrated that the kinetics of 18 F-DPA-714 differs in injured tissue compared to normal tissue. Therefore, 18 F-DPA-714 may be useful in assessing the extent of neuroinflammation associated with acute stroke and could also help to predict clinical outcomes and functional recovery, as well as to assess therapeutic strategies, such as the use of neuroprotective/anti-inflammatory drugs.

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Objective. The objective of this study was to compare glucose metabolism and atrophy, in the precuneus and cingulate cortex, in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI), using FreeSurfer. Methods. 47 individuals (17 patients with AD, 17 patients with amnestic MCI, and 13 healthy controls (HC)) were included. MRI and PET images using 18F-FDG (mean injected dose of 185 MBq) were acquired and analyzed using FreeSurfer to define regions of interest in the hippocampus, amygdala, precuneus, and anterior and posterior cingulate cortex. Regional volumes were generated. PET images were registered to the T1-weighted MRI images and regional uptake normalized by cerebellum uptake (SUVr) was measured. Results. Mean posterior cingulate volume was reduced in MCI and AD. SUVr were different between the three groups: mean precuneus SUVr was 1.02 for AD, 1.09 for MCI, and 1.26 for controls (p < 0.05); mean posterior cingulate SUVr was 0.96, 1.06, and 1.22 for AD, MCI, and controls, respectively (p < 0.05). Conclusion. We found graduated hypometabolism in the posterior cingulate cortex and the precuneus in prodromal AD (MCI) and AD, whereas atrophy was not significant. This suggests that the use of 18F-FDG in these two regions could be a neurodegenerative biomarker.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a treatable brainstem encephalitis recently described by Pittock et al. [1]. We report a case with clinical, radiological, and pathological signs of CLIPPERS but with final diagnosis of type B primary central nervous system lymphoma (PCNSL).In March 2010, a 33-year-old man with unremarkable personal history was first seen in the internal medicine unit for isolated vomiting with weight loss of 5 kg. The clinical and paraclinical examinations were unremarkable. In June, he was admitted to our unit for subacute gait ataxia, dysphagia, and binocular diplopia. Clinical examination revealed bilateral sixth nerve palsy and gait ataxia with pyramidal signs. Brain magnetic resonance imaging (MRI) showed hyperintense lesions on T2-weighted and fluidattenuated inversion recovery (FLAIR) sequences within the pons, medulla, and upper cervical cord, with enhancement after gadolinium administration. Cerebrospinal fluid (CSF) analysis showed elevated levels of proteins (1.10 g/l) with normal electrophoretic pattern and without abnormal cell count (2/mm 3 ). Extensive laboratory investigations were normal. Whole-body fluorodeoxyglucose positron emission tomography (FDG-PET), and labial salivary gland biopsies were negative, including aquaporin-4 water channel and onconeural antibodies. Biopsy of pons revealed perivascular lymphocyte infiltrates without any findings of sarcoidosis, lymphoma, glioma, or lymphomatoid granulomatosis (Fig. 1d). CLIPPERS syndrome was suspected, and the patient was treated for five consecutive days with 1,000 mg intravenous methylprednisolone followed by oral prednisone 60 mg (1 mg/kg/day) every day, with dramatic recovery except for persistence of moderate gait ataxia. In August 2010, a second brain MRI showed a reduction in the number and size of brainstem lesions. Localized proton magnetic resonance spectroscopy (MRS) examination showed a slight decrease of N-acetyl-aspartate/creatine (NAA/Cr) ratio (1:52) and an increase in choline/creatine (Cho/Cr) ratio (1:58) in the brain and medulla (Fig. 1a). The dose of steroids was reduced by 10 mg/week until 30 mg/ day was reached. In September 2010, he complained of numbness in all four limbs with worsening gait ataxia. A third brain MRI showed enlargement of the pontine lesions with necrosis. The MRS showed a slightly elevated Cho/ NAA ratio, as well as strong resonance of lipids and lactates (Fig. 1b). The patient was then treated with 1,000 mg intravenous methylprednisolone for 5 days; this was followed by double-filtration plasmapheresis. Because no further clinical improvement was observed, monthly intravenous cyclophosphamide was added. In October, the fourth brain MRI revealed radiological progression of brainstem lesions with the appearance of gadoliniumenhanced lesions localized close to the left lateral ventricle.