Brain Hemisphere Dissimilarity, a Self-Supervised Learning Approach for alpha-synucleinopathies prediction with FDG PET.

Idiopathic Rem sleep Behavior Disorder (iRBD) is a significant biomarker for the development of alpha-synucleinopathies, such as Parkinson's disease (PD) or Dementia with Lewy bodies (DLB). Methods to identify patterns in iRBD patients can help in the prediction of the future conversion to these diseases during the long prodromal phase when symptoms are non-specific. These methods are essential for disease management and clinical trial recruitment. Brain PET scans with 18F-FDG PET radiotracers have recently shown promise, however, the scarcity of longitudinal data and PD/DLB conversion information makes the use of representation learning approaches such as deep convolutional networks not feasible if trained in a supervised manner. In this work, we propose a self-supervised learning strategy to learn features by comparing the brain hemispheres of iRBD non-convertor subjects, which allows for pre-training a convolutional network on a small data regimen. We introduce a loss function called hemisphere dissimilarity loss (HDL), which extends the Barlow Twins loss, that promotes the creation of invariant and non-redundant features for brain hemispheres of the same subject, and the opposite for hemispheres of different subjects. This loss enables the pre-training of a network without any information about the disease, which is then used to generate full brain feature vectors that are fine-tuned to two downstream tasks: follow-up conversion, and the type of conversion (PD or DLB) using baseline 18F-FDG PET. In our results, we find that the HDL outperforms the variational autoencoder with different forms of inputs.

Cambios metabólicos corticales y resultado clínico en la hidrocefalia normotensiva después de la derivación ventrículo-peritoneal: nuestros resultados preliminares / Cortical metabolic changes and clinical outcome in normal pressure hydrocephalus after ventriculoperitoneal shunt: our preliminary results

INTRODUCCIÓN: Nuestro objetivo fue evaluar los cambios metabólicos corticales y el resultado clínico en los pacientes afectados por la hidrocefalia idiopática de presión normal (iNPH) después de la colocación de una derivación ventriculoperitoneal (VP). MATERIALES Y MÉTODOS: Diez pacientes afectados por la sospecha de iNPH se sometieron a una evaluación de la hidrodinámica del LCR basada en una prueba de infusión lumbar. El principal criterio de selección para la cirugía se basó en la elasticidad intracraneal (EI)>0,30. Todos los sujetos con una EI> 0,30 se sometieron a una exploración PET con 18 fluorodesoxiglucosa (18F-FDG) en la línea de base (PET1) y un mes después de la cirugía (PET2). Además, los mismos pacientes fueron sometidos a una evaluación clínica antes y un mes después de la cirugía mediante pruebas neuropsicológicas y análisis de la marcha. RESULTADOS: Se realizó un número total de 20 exploraciones de PET 18F-FDG en todos los pacientes reclutados. En comparación con la PET1, la PET2 mostró un aumento en el consumo de glucosa en el lóbulo frontal izquierdo y el lóbulo parietal izquierdo en la PET2 en comparación con la PET1 (p < 0,001). Todos los pacientes reclutados presentaron un aumento significativo en las puntuaciones neuropsicológicas (i.e. Batería de evaluación frontal y Evaluación cognitiva de Montreal) y han mejorado clínicamente en el análisis de la marcha. Se encontró una correlación significativa entre el aumento del consumo de glucosa cortical en el área parietal izquierda y la mejoría cognitiva detectable por la evaluación neuropsicológica. CONCLUSIONES: La mejora en 18F-FDG PET del metabolismo de la glucosa podría considerarse un marcador de imagen útil para la evaluación de la respuesta de la iNPH a la derivación ventriculoperitoneal

INTRODUCTION: Our objective was to evaluate the cortical metabolic changes and clinical outcome in patients affected by idiopathic normal pressure hydrocephalus (iNPH) after a placement of ventriculoperitoneal (VP) shunt. MATERIALS AND METHODS: 10 patients affected by suspected iNPH underwent a CSF hydrodynamics evaluation based on a lumbar infusion test (LIT). The main selection criterion for surgery was based on intracranial elasticity (IE)>0.30. All subjects with an IE>0.30 underwent a PET scan with 18 fluorodeoxiglucose (18F-FDG) at baseline (PET1) and 1 month after surgery (PET2). Furthermore, the same patients were submitted to clinical evaluation before and 1 month after surgery through neuropsychological tests and gait analysis. RESULTS: An overall number of 20 18F-FDG PET scans were performed in all the enrolled patients. As compared to PET1, PET2 showed an increase in glucose consumption in the left frontal and left parietal lobe in PET2 as compared to PET1 (P<.001). All the enrolled patients presented a significant increase in neuropsychological scores (i.e Frontal Assessment Battery and Montreal Cognitive Assessment) and have clinically improved at gait analysis. A significant correlation was found between the increase of cortical glucose consumption in the left parietal area and the cognitive improvement as detectable by neuropsychological assessment. CONCLUSIONS: Improvement in 18F FDG PET glucose metabolism could be considered a useful imaging marker for the assessment of iNPH response to VP shunting

Cortical metabolic changes and clinical outcome in normal pressure hydrocephalus after ventriculoperitoneal shunt: Our preliminary results. / Cambios metabólicos corticales y resultado clínico en la hidrocefalia normotensiva después de la derivación ventrículo-peritoneal: nuestros resultados preliminares.

INTRODUCTION: Our objective was to evaluate the cortical metabolic changes and clinical outcome in patients affected by idiopathic normal pressure hydrocephalus (iNPH) after a placement of ventriculoperitoneal (VP) shunt. MATERIALS AND METHODS: 10 patients affected by suspected iNPH underwent a CSF hydrodynamics evaluation based on a lumbar infusion test (LIT). The main selection criterion for surgery was based on intracranial elasticity (IE)>0.30. All subjects with an IE>0.30 underwent a PET scan with 18 fluorodeoxiglucose (18F-FDG) at baseline (PET1) and 1 month after surgery (PET2). Furthermore, the same patients were submitted to clinical evaluation before and 1 month after surgery through neuropsychological tests and gait analysis. RESULTS: An overall number of 20 18F-FDG PET scans were performed in all the enrolled patients. As compared to PET1, PET2 showed an increase in glucose consumption in the left frontal and left parietal lobe in PET2 as compared to PET1 (P<.001). All the enrolled patients presented a significant increase in neuropsychological scores (i.e Frontal Assessment Battery and Montreal Cognitive Assessment) and have clinically improved at gait analysis. A significant correlation was found between the increase of cortical glucose consumption in the left parietal area and the cognitive improvement as detectable by neuropsychological assessment. CONCLUSIONS: Improvement in 18F FDG PET glucose metabolism could be considered a useful imaging marker for the assessment of iNPH response to VP shunting.

Hearing and cognitive impairment: a functional evaluation of associative brain areas in patients affected by Alzheimer's disease.

Auditory dysfunction observed in patients with cognitive diseases is probably due to the alteration of some brain areas involved in sound stimulus processing. The present study aimed to investigate differences in such processing and in connectivity of the primary auditory cortex in patients affected by Alzheimer's disease (AD) and in normal subjects. We examined 131 diagnosed AD patients and a control group (CG) of 36 normal subjects. After a complete clinical investigation, focused on hearing function, all subjects underwent a brain FDG PET/CT. AD subjects vs CG showed reduced glucose consumption in BA 6,7,8,39, whereas we did not find differences in the primary auditory cortex. In AD, connectivity analyses showed a positive correlation of the primary auditory cortex with BA 6,8,21,31,39,40,42 and a negative correlation with BA 19, cerebellum and basal ganglia. Our findings suggest that neurological evaluation of patients with hearing loss might allow earlier (preclinical) identification of those affected by cognitive impairment.

A deep look into thin melanomas: What's new for the clinician and the impact on the patient.

Melanoma incidence and mortality are on the rise and although most new cases of melanoma are thin, a significant percentage of these patients still experience disease progression. The American Joint Committee on Cancer publishes staging criteria for melanoma, which were recently updated to the 8th edition. The most significant revision from the 7th edition affects the T1b classification, which now includes melanomas with a Breslow depth of 0.8 mm to 1.0 mm. The second major revision eliminates mitoses as a criterion to upstage a thin melanoma to T1b. Although mitotic figures have been established as an independent prognostic factor, they do not have a significant correlation with sentinel lymph node (SLN) biopsy positivity. SLN status remains the most important independent prognostic factor in thin melanomas. Nonetheless, the identification of patients who are at the highest risk for having a positive SLN test result remains difficult. Importantly, a positive SLN test result has high positive predictive value, but a negative one has very low negative predictive value. Since there is no proven survival benefit in performing an SLN biopsy in T1 disease, dermatologists need to have a personalized discussion with patients with thin melanomas to review expected risks and benefits before undertaking this procedure.

Laser treatment of medical skin disease in women.

Laser treatment is a relatively new and increasingly popular modality for the treatment of many dermatologic conditions. A number of conditions that predominantly occur in women and that have a paucity of effective treatments include rosacea, connective tissue disease, melasma, nevus of Ota, lichen sclerosus (LS), notalgia paresthetica and macular amyloidosis, and syringomas. Laser therapy is an important option for the treatment of patients with these conditions. This article will review the body of literature that exists for the laser treatment of women with these medical conditions.

Comparison of 18F FDOPA PET, DSC-MRI and spectroscopy in a patient with brain metastatic lesions from lung cancer / Comparación de los 18F FDOPA PET, DSC-MRI y espectroscopia en un paciente con lesiones metastásicas cerebrales de cáncer de pulmón

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Aspects of cerebral plasticity related to clinical features in acute vestibular neuritis: a "starting point" review from neuroimaging studies.

Vestibular neuritis (VN) is one of the most common causes of vertigo and is characterised by a sudden unilateral vestibular failure (UVF). Many neuroimaging studies in the last 10 years have focused on brain changes related to sudden vestibular deafferentation as in VN. However, most of these studies, also due to different possibilities across diverse centres, were based on different times of first acquisition from the onset of VN symptoms, neuroimaging techniques, statistical analysis and correlation with otoneurological and psychological findings. In the present review, the authors aim to merge together the similarities and discrepancies across various investigations that have employed neuroimaging techniques and group analysis with the purpose of better understanding about how the brain changes and what characteristic clinical features may relate to each other in the acute phase of VN. Six studies that strictly met inclusion criteria were analysed to assess cortical-subcortical correlates of acute clinical features related to VN. The present review clearly reveals that sudden UVF may induce a wide variety of cortical and subcortical responses - with changes in different sensory modules - as a result of acute plasticity in the central nervous system.

Decoupled association between 18F-FDG and 18F-FDOPA uptake in a carcinoid of the thymus / Captación disociada de 18F-FDG y 18F-FDOPA en un carcinoide del timo

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18F FDOPA uptake in brain metastasis of breast cancer / Captación de 18F FDOPA en metástasis cerebral de un cáncer de mama

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A case of intracranial meningioma detected by 18F-choline PET/CT and examined by PET/MRI fusion imaging / Un caso de meningioma intracraneal detectado por 18F-colina PET/TC y la imagen de fusión PET/RM

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18F-FDG PET/RM en la encefalitis por virus herpes simple: un caso clínico / 8F-FDG PET/MR in herpes simplex virus encephalitis: A case study

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Reverse perfusion pattern in myocardial spect with 99mTc-sestaMIBI.

RATIONALE: The aim of our study was to investigate the myocardial perfusion deficit in rest images as compared to stress images in myocardial scintigraphy (MS). OBJECTIVES: The aim of this study is to investigate the reverse perfusion (RP) pattern in MS. METHODS AND RESULTS: 263 patients were enrolled in the study (72 females and 191 males; mean age 65.7 ± 9.5 years old). Mean body mass index (BMI) was of 27.6 ± 3.8 Kg/m2. 115 patients were positive for a previous history of myocardial infarction (MI). 142 patients reported a revascularization treatment (percutaneous transluminal coronary angioplasty, PTCA, cardiac stent placement, coronary artery bypass grafting, CABG). All the patients underwent MS following standard single day Stress/Rest protocol. In our series, 27 patients presented a RP pattern. We did not find statistically significant differences when considering age (p = 0.7988), sex (p = 0.0657), BMI (p = 0.8611), diabetes (p = 0.8259), dyslipidemia (p = 0.1464) or smoking status (p = 0.6829) in RP patients vs. non-RP patients. A history of MI is related to a RP pattern (p < 0.0001). A history of previous revascularization was not related with RP (p = 0.6868). DISCUSSION: The result of our study suggested that RP is probably related to artifacts of various origins. Further studies are necessary especially in microvascular dysfunction or a long history of disease.