PCA and logistic regression in 2-[18F]FDG PET neuroimaging as an interpretable and diagnostic tool for Alzheimer's disease.

Objective.to develop an optimization and training pipeline for a classification model based on principal component analysis and logistic regression using neuroimages from PET with 2-[18F]fluoro-2-deoxy-D-glucose (FDG PET) for the diagnosis of Alzheimer's disease (AD).Approach.as training data, 200 FDG PET neuroimages were used, 100 from the group of patients with AD and 100 from the group of cognitively normal subjects (CN), downloaded from the repository of the Alzheimer's Disease Neuroimaging Initiative (ADNI). Regularization methods L1 and L2 were tested and their respective strength varied by the hyperparameter C. Once the best combination of hyperparameters was determined, it was used to train the final classification model, which was then applied to test data, consisting of 192 FDG PET neuroimages, 100 from subjects with no evidence of AD (nAD) and 92 from the AD group, obtained at the Centro de Diagnóstico por Imagem (CDI).Main results.the best combination of hyperparameters was L1 regularization andC≈ 0.316. The final results on test data were accuracy = 88.54%, recall = 90.22%, precision = 86.46% and AUC = 94.75%, indicating that there was a good generalization to neuroimages outside the training set. Adjusting each principal component by its respective weight, an interpretable image was obtained that represents the regions of greater or lesser probability for AD given high voxel intensities. The resulting image matches what is expected by the pathophysiology of AD.Significance.our classification model was trained on publicly available and robust data and tested, with good results, on clinical routine data. Our study shows that it serves as a powerful and interpretable tool capable of assisting in the diagnosis of AD in the possession of FDG PET neuroimages. The relationship between classification model output scores and AD progression can and should be explored in future studies.

Temporal and spatial changes in cerebral blood flow in neuropsychiatric systemic lupus erythematosus: a subtraction brain spect study.

This study was addressed to evaluate the temporal and spatial changes in regional cerebral blood flow (rCBF) of patients with neuropsychiatric systemic lupus erythematosus (NPSLE). Our objective was to correlate the subtracted SPECT coregistered to MRI features (SISCOM) with demographic, clinical and laboratory findings to shed light upon the pathophysiological evolution of the NPSLE. Twenty-six NPSLE patients with MRI and pre- and post-treatment brain SPECT with [99mTc]Tc-ECD. SISCOM features were categorized as improvement, worsening, activation and/or deactivation of rCBF findings. Patients mean age of 43.19 years and 65.38% white were evaluated. The patients mean age at onset of SLE was 26.05 and 42.29 for NPSLE. The mean time between the onset of SLE and first NPSLE symptoms was 05.57 years. The disease has already been initiated as NPSLE in 4 patients. The SLEDAI average score was 31.69 and the SLICC/ACR-DI score was 06.96. The patients underwent an average of 09.23 cyclophosphamide. The SISCOM findings showed functional and pathological states on different brain regions. The rCBF changes were not associated with index scores. There was, however, a trend towards an association between lower SLEDAI scores with improvement and higher SLEDAI with worsening in SISCOM, Also a trend of association between lower SLICC score with improvement, and higher SLICC with worsening. The female gender was predictive of activation and worsening, separately, and deactivation and worsening in a set. Non-white patients were predictive of worsening. The seizure was predictive of deactivation separately, and deactivation and worsening in a set. Finally, normal C3 was a predictor of improvement. The present study showed dynamic brain changes in NPSLE patients. SISCOM technique showed improved rCBF in some brain areas, and worsening, activation and deactivation in others. There were associations between rCBF changes and gender, skin colour and complement C3 and association trends with SLEDAI and SLICC scores.

Influences of weight, age, gender, genetics, diseases, and ethnicity on bitterness perception: a narrative review of current methodological aspects

BACKGROUND: Bitterness perception seems to be related to an enhanced intake of dietary fat and to a tendency to the development of diseases such as obesity. However, the exact factors for this possible contribution still need to be better investigated. So, gustatory perception of the bitter taste is a promising area of study because of its importance regarding food choices and consequently feeding behavior. Therefore, this short review focused on recent papers reporting correlations between bitter taste, anthropometric variables, obesity and other chronic diseases, age, gender, ethnicity, and genetics. METHODS: A survey was performed in MEDLINE (PubMed) and Scielo from September 2015 to January 2017.Only review articles, observational studies and clinical trials published in English and Portuguese over the last15 years which met the objectives of the present study were considered. A total of 40 papers were evaluated. RESULTS: Two papers showed a positive correlation between bitter taste and obesity, one indicated that this correlation is influenced by the subject's age, one suggested a negative correlation, and two found no association. Age seems to be negatively correlated with the bitterness perceived, and female gender was associated with a stronger perception of bitterness. Genetics, mostly due to differences in TAS2R38 expression, influences sensitivity to the bitter taste, feeding behavior and also alcohol intake. Ethnicity, not only the subject's phenotypic or genotypic characteristics, seems to play a role in taste perception and nutritional diseases. CONCLUSIONS: Age, gender, genetics and ethnicity seem to play a role in bitterness perception. Data about associations between bitterness perception and anthropometrics are conflicting.

18F-FDG PET/CT/MRI Fusion Images Showing Cranial and Peripheral Nerve Involvement in Neurolymphomatosis.

We report a 56-year-old female patient with non-Hodgkin's diffuse large B cell lymphoma (NHL) who, on magnetic resonance imaging (MRI) with a T1 weighted and gadolinium-enhanced imaging, was found to have thickening and infiltration in 75% of peripheral nerves of the patient and enlargements of cranial nerves, possibly related to lymphomatous infiltration. Subsequent positron emission tomography/computed tomography (PET/CT) using 18F-labeled 2-deoxy-2-fluoro-d-glucose (18F-FDG) showed widespread active involvement of the cervical plexus, bilateral peripheral nerves, right femoral nerve, the parasellar region of the skull, and marked hypermetabolism in the left trigeminal ganglia. This case re-emphasizes that while CT and MRI provide anatomical details, 18F-FDG PET/CT images better delineate the metabolic activity of neurolymphomatosis (NL) in the peripheral and central nervous system.

Systematic review of the efficacy in seizure control and safety of neuronavigation in epilepsy surgery: The need for well-designed prospective studies.

PURPOSE: To evaluate the efficacy of surgery with neuronavigation compared to conventional neurosurgical treatment of epilepsy in terms of safety and seizure outcomes and to assess the quality of the evidence base of neuronavigation in this clinical context. METHOD: Systematic review using the electronic databases of Cochrane, CRD, PubMed, Embase, SciELO and LILACS in Portuguese, English and Spanish. The [MeSH] terms included "epilepsy" and "neuronavigation". ELIGIBILITY CRITERIA: Studies assessing surgery with neuronavigation for the surgical treatment of epilepsy or brain injuries associated with epileptic seizures. RESULTS: We identified 28 original articles. All articles yielded scientific evidence of low quality. Outcome data presented in the articles identified was heterogeneous and did not amount to compelling evidence that epilepsy surgery with neuronavigation produces higher rates of seizure control, a reduced need for reoperations, or lower rates of complications or postoperative neurological deficits. CONCLUSION: We were unable to find any publications providing convincing evidence that neuronavigation improves outcomes of epilepsy surgery. Whilst this does not mean that neuronavigation cannot improve neurosurgical outcomes in this clinical setting, well-designed research studies evaluating the role of neuronavigation are urgently needed.