Metabolic connectivity as index of verbal working memory.

Positron emission tomography (PET) data are commonly analyzed in terms of regional intensity, while covariant information is not taken into account. Here, we searched for network correlates of healthy cognitive function in resting state PET data. PET with [(18)F]-fluorodeoxyglucose and a test of verbal working memory (WM) were administered to 35 young healthy adults. Metabolic connectivity was modeled at a group level using sparse inverse covariance estimation. Among 13 WM-relevant Brodmann areas (BAs), 6 appeared to be robustly connected. Connectivity within this network was significantly stronger in subjects with above-median WM performance. In respect to regional intensity, i.e., metabolism, no difference between groups was found. The results encourage examination of covariant patterns in FDG-PET data from non-neurodegenerative populations.

Migration of antimony from polyethylene terephthalate used in mineral water bottles.

The influence of storage time and temperature on Sb migration from PET bottles into mineral water was studied in short-term tests lasting up to 15 days and long-term studies lasting up to 220 days. Samples purchased were stored in three different coloured bottles: clear (CL), light blue (LB) and dark blue (DB). Sb migration was assayed by HG-AFS for total determination and HPLC-ICP-MS for speciation analysis. Migration studies showed that waters stored at 4 and 20 oC were not subject to Sb migration. At 40 oC there was a significant increase in Sb concentration, although the maximum limit established by the European Union (5.0 ug/L) was not exceeded, whereas at 60 oC samples were subject to considerable Sb migration after 30 days of storage. In this case, the maximum limit established by the European Union was exceeded and both Sb (V) and Sb (III) were detected.

Water availability predicts forest canopy height at the global scale.

The tendency of trees to grow taller with increasing water availability is common knowledge. Yet a robust, universal relationship between the spatial distribution of water availability and forest canopy height (H) is lacking. Here, we created a global water availability map by calculating an annual budget as the difference between precipitation (P) and potential evapotranspiration (PET) at a 1-km spatial resolution, and in turn correlated it with a global H map of the same resolution. Across forested areas over the globe, Hmean increased with P-PET, roughly: Hmean (m) = 19.3 + 0.077*(P-PET). Maximum forest canopy height also increased gradually from ~ 5 to ~ 50 m, saturating at ~ 45 m for P-PET > 500 mm. Forests were far from their maximum height potential in cold, boreal regions and in disturbed areas. The strong association between forest height and P-PET provides a useful tool when studying future forest dynamics under climate change, and in quantifying anthropogenic forest disturbance.

Spleen Volume Variation in Patients with Locally Advanced Non-Small Cell Lung Cancer Receiving Platinum-Based Chemo-Radiotherapy.

There is renewed interest in the immune regulatory role of the spleen in oncology. To date, very few studies have examined macroscopic variations of splenic volume in the setting of cancer, prior to or during therapy, especially in humans. Changes in splenic volume may be associated with changes in splenic function. The purpose of this study was to investigate variations in spleen volume in NSCLC patients during chemo-radiotherapy. Sixty patients with stage I-IIIB NSCLC underwent radiotherapy (60Gy/30 fractions) for six weeks with concomitant carboplatin/paclitaxel (Ca/P; n = 32) or cisplatin/etoposide (Ci/E; n = 28). A baseline PET/CT scan was performed within 2 weeks prior to treatment and during Weeks 2 and 4 of chemo-radiotherapy. Spleen volume was measured by contouring all CT slices. Significant macroscopic changes in splenic volume occurred early after the commencement of treatment. A significant decrease in spleen volume was observed for 66% of Ca/P and 79% of Ci/E patients between baseline and Week 2. Spleen volume was decreased by 14.2% for Ca/P (p<0.001) and 19.3% for Ci/E (p<0.001) patients. By Week 4, spleen volume was still significantly decreased for Ca/P patients compared to baseline, while for Ci/E patients, spleen volume returned to above baseline levels. This is the first report demonstrating macroscopic changes in the spleen in NSCLC patients undergoing radical chemo-radiotherapy that can be visualized by non-invasive imaging.

Diagnostic methods and treatment options for focal cortical dysplasia.

Our inability to adequately treat many patients with refractory epilepsy caused by focal cortical dysplasia (FCD), surgical inaccessibility and failures are significant clinical drawbacks. The targeting of physiologic features of epileptogenesis in FCD and colocalizing functionality has enhanced completeness of surgical resection, the main determinant of outcome. Electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) and magnetoencephalography are helpful in guiding electrode implantation and surgical treatment, and high-frequency oscillations help defining the extent of the epileptogenic dysplasia. Ultra high-field MRI has a role in understanding the laminar organization of the cortex, and fluorodeoxyglucose-positron emission tomography (FDG-PET) is highly sensitive for detecting FCD in MRI-negative cases. Multimodal imaging is clinically valuable, either by improving the rate of postoperative seizure freedom or by reducing postoperative deficits. However, there is no level 1 evidence that it improves outcomes. Proof for a specific effect of antiepileptic drugs (AEDs) in FCD is lacking. Pathogenic mutations recently described in mammalian target of rapamycin (mTOR) genes in FCD have yielded important insights into novel treatment options with mTOR inhibitors, which might represent an example of personalized treatment of epilepsy based on the known mechanisms of disease. The ketogenic diet (KD) has been demonstrated to be particularly effective in children with epilepsy caused by structural abnormalities, especially FCD. It attenuates epigenetic chromatin modifications, a master regulator for gene expression and functional adaptation of the cell, thereby modifying disease progression. This could imply lasting benefit of dietary manipulation. Neurostimulation techniques have produced variable clinical outcomes in FCD. In widespread dysplasias, vagus nerve stimulation (VNS) has achieved responder rates >50%; however, the efficacy of noninvasive cranial nerve stimulation modalities such as transcutaneous VNS (tVNS) and noninvasive (nVNS) requires further study. Although review of current strategies underscores the serious shortcomings of treatment-resistant cases, initial evidence from novel approaches suggests that future success is possible.

Verifique sus conocimientos sobre medicina nuclear (1): gammagrafía

La presente entrega de la serie de Nursing sobre pruebas complementarias está dedicada a la gammagrafía. La gammagrafía es una técnica de diagnóstico por la imagen de medicina nuclear. Las exploraciones de medicina nuclear se pueden clasificar en medicina nuclear convencional (gammagrafía) y medicina nuclear por tomografía por emisión de positrones (PET), que se estudiará en la siguiente entrega de Nursing sobre pruebas complementarias. La gammagrafía es una técnica diagnóstica que utiliza sustancias radiactivas (isótopos) para estudiar la anatomía y el funcionalismo de diferentes órganos y tejidos del cuerpo. La gran ventaja de esta modalidad diagnóstica es su carácter funcional y su capacidad para evidenciar procesos pre-anatómicos de desarrollo patológico o anómalo que, junto con su elevada sensibilidad, permite diagnosticar alteraciones en fases muy precoces para poder ser tratadas. En el presente artículo se exponen las pruebas diagnósticas de gammagrafía más habituales, teniendo en cuenta que también existe la posibilidad de tratamientos terapéuticos que no son objeto de este trabajo. La enfermera, además del cuidado del paciente durante la preparación y después de la técnica, puede resolver las inquietudes relacionadas con las exploraciones gammagráficas, que normalmente tienen que ver con las características de cada prueba, la duración y el grado de molestia.

Verifique sus conocimientos sobre medicina nuclear (1): gammagrafía

La presente entrega de la serie de Nursing sobre pruebas complementarias está dedicada a la gammagrafía. La gammagrafía es una técnica de diagnóstico por la imagen de medicina nuclear. Las exploraciones de medicina nuclear se pueden clasificar en medicina nuclear convencional (gammagrafía) y medicina nuclear por tomografía por emisión de positrones (PET), que se estudiará en la siguiente entrega de Nursing sobre pruebas complementarias. La gammagrafía es una técnica diagnóstica que utiliza sustancias radiactivas (isótopos) para estudiar la anatomía y el funcionalismo de diferentes órganos y tejidos del cuerpo. La gran ventaja de esta modalidad diagnóstica es su carácter funcional y su capacidad para evidenciar procesos pre-anatómicos de desarrollo patológico o anómalo que, junto con su elevada sensibilidad, permite diagnosticar alteraciones en fases muy precoces para poder ser tratadas. En el presente artículo se exponen las pruebas diagnósticas de gammagrafía más habituales, teniendo en cuenta que también existe la posibilidad de tratamientos terapéuticos que no son objeto de este trabajo. La enfermera, además del cuidado del paciente durante la preparación y después de la técnica, puede resolver las inquietudes relacionadas con las exploraciones gammagráficas, que normalmente tienen que ver con las características de cada prueba, la duración y el grado de molestia.

Graduating 4th year radiology residents' perception of optimal imaging modalities for neoplasm and trauma: a pilot study from four U.S. universities

OBJECTIVE: Our purpose was to assess 4th year radiology residents' perception of the optimal imaging modality to investigate neoplasm and trauma. MATERIALS AND METHODS: Twenty-seven 4th year radiology residents from four residency programs were surveyed. They were asked about the best imaging modality to evaluate the brain and spine, lungs, abdomen, and the musculoskeletal system. Imaging modalities available were MRI, CT, ultrasound, PET, and X-ray. All findings were compared to the ACR appropriateness criteria. RESULTS: MRI was chosen as the best imaging modality to evaluate brain, spine, abdominal, and musculoskeletal neoplasm in 96.3%, 100%, 70.4%, and 63% of residents, respectively. CT was chosen by 88.9% to evaluate neoplasm of the lung. Optimal imaging modality to evaluate trauma was CT for brain injuries (100%), spine (92.6%), lung (96.3%), abdomen (92.6%), and major musculoskeletal trauma (74.1%); MRI was chosen for sports injury (96.3%). There was agreement with ACR appropriateness criteria. CONCLUSION: Residents' perception of the best imaging modalities for neoplasm and trauma concurred with the appropriateness criteria by the ACR.

Thoracic fat volume is independently associated with coronary vasomotion.

PURPOSE: Thoracic fat has been associated with an increased risk of coronary artery disease (CAD). As endothelium-dependent vasoreactivity is a surrogate of cardiovascular events and is impaired early in atherosclerosis, we aimed at assessing the possible relationship between thoracic fat volume (TFV) and endothelium-dependent coronary vasomotion. METHODS: Fifty healthy volunteers without known CAD or major cardiovascular risk factors (CRFs) prospectively underwent a (82)Rb cardiac PET/CT to quantify myocardial blood flow (MBF) at rest, and MBF response to cold pressor testing (CPT-MBF) and adenosine (i.e., stress-MBF). TFV was measured by a 2D volumetric CT method and common laboratory blood tests (glucose and insulin levels, HOMA-IR, cholesterol, triglyceride, hsCRP) were performed. Relationships between CPT-MBF, TFV and other CRFs were assessed using non-parametric Spearman rank correlation testing and multivariate linear regression analysis. RESULTS: All of the 50 participants (58 ± 10y) had normal stress-MBF (2.7 ± 0.6 mL/min/g; 95 % CI: 2.6-2.9) and myocardial flow reserve (2.8 ± 0.8; 95 % CI: 2.6-3.0) excluding underlying CAD. Univariate analysis revealed a significant inverse relation between absolute CPT-MBF and sex (ρ = -0.47, p = 0.0006), triglyceride (ρ = -0.32, p = 0.024) and insulin levels (ρ = -0.43, p = 0.0024), HOMA-IR (ρ = -0.39, p = 0.007), BMI (ρ = -0.51, p = 0.0002) and TFV (ρ = -0.52, p = 0.0001). MBF response to adenosine was also correlated with TFV (ρ = -0.32, p = 0.026). On multivariate analysis, TFV emerged as the only significant predictor of MBF response to CPT (p = 0.014). CONCLUSIONS: TFV is significantly correlated with endothelium-dependent and -independent coronary vasomotion. High TF burden might negatively influence MBF response to CPT and to adenosine stress, even in persons without CAD, suggesting a link between thoracic fat and future cardiovascular events.

Aplicações da técnica de difusão por RM em cabeça e pescoço: um olhar além da anatomia

DWI é uma técnica totalmente não invasiva que tem sido utilizada com sucesso por muitos anos em imagens do cérebro e recentemente incluída como parte da avaliação de outros sistemas, por exemplo, no abdome e pelve e na cabeça e pescoço. Apesar de a DWI e a medida dos valores de ADC serem capazes de fornecer informações de tipos histológicos específicos de tumores, a maioria dos centros de imagem ainda não os adotaram como parte da rotina na avaliação da cabeça e pescoço. A medida de ADC demonstrou ser útil para discriminar tipos específicos de tumores histológicos, especialmente para diferenciar lesões benignas sólidas de massas malignas, importante na avaliação de linfonodos cervicais, principalmente para diferenciar processos nodais benignos de malignos, para diferenciar as alterações pós-radioterapia de tumor residual e ter uso potencial para predizer sucesso terapêutico. Além disso, DWI/ADC parece ser um método mais seguro e mais acessível, considerando a ausência de radiação ionizante e ao maior custo do FDG-PET na localização de tumores e diferenciar massas benignas de malignas. Com todas essas vantagens e potencialidades, DWI/ADC certamente fará parte da rotina na avaliação por imagem da cabeça e pescoço.

A tomografia por emissão de pósitrons com 2-[18F]-fluoro-2-desoxi-D-glicose é custo-efetiva em pacientes com câncer de pulmão não pequenas células no Brasil

OBJETIVO: Comparar a acurácia e a custo-efetividade do estadiamento metabólico (EM) com o FDG-PET em relação ao estadiamento convencional (EC) no estadiamento inicial de pacientes com câncer de pulmão não pequenas células (CPNPC). MATERIAIS E MÉTODOS: Noventa e cinco pacientes com diagnóstico inicial de CPNPC foram estadiados antes do início do tratamento. Os resultados do EC e EM foram comparados quanto a definição do tratamento e incidência de toracotomia fútil em cada estratégia. RESULTADOS: O EM com FDG-PET classificou 48,4% dos pacientes como estádio mais avançado e 5,3% como menos avançado. O resultado do EM modificaria o tratamento em 41% dos pacientes. A toracotomia foi considerada fútil em 47% dos pacientes com EC e em 19% dos casos com EM. O custo das toracotomias fúteis em oito pacientes no EM foi de R$ 79.720, enquanto em 31 pacientes no EC seria de R$ 308.915. Apenas esta economia seria mais que suficiente para cobrir os custos de todos os exames de FDG-PET nos 95 pacientes (R$ 126.350) ou de FDG-PET/CT (R$ 193.515). CONCLUSÃO: O EM com FDG-PET tem maior acurácia que o EC em pacientes com CPNPC. A FDG-PET e FDG-PET/CT são custo-efetivas e sua utilização se justifica economicamente na saúde pública no Brasil.

Biópsia percutânea de lesões ósseas guiada por tomografia computadorizada: taxas de definição diagnóstica e complicações

Objetivo: Determinar taxas de definição diagnóstica e complicações da biópsia percutânea guiada por tomografia computadorizada (TC) de lesões ósseas suspeitas de malignidade. Materiais e Métodos: Estudo retrospectivo que incluiu 186 casos de biópsia percutânea guiada por TC de lesões ósseas no período de janeiro de 2010 a dezembro de 2012. Todas as amostras foram obtidas usando agulhas de 8 a 10 gauge. Foram coletados dados demográficos, história de neoplasia maligna prévia, dados relacionados à lesão, ao procedimento e ao resultado histológico. Resultados: A maioria dos pacientes era do sexo feminino (57%) e a idade média foi 53,0 ± 16,4 anos. Em 139 casos (74,6%) a suspeita diagnóstica era metástase e os tumores primários mais comuns foram de mama (32,1%) e próstata (11,8%). Os ossos mais envolvidos foram coluna vertebral (36,0%), bacia (32,8%) e ossos longos (18,3%). Houve complicações em apenas três pacientes (1,6%), incluindo uma fratura, um caso de parestesia com comprometimento funcional e uma quebra da agulha necessitando remoção cirúrgica. Amostras de 183 lesões (98,4%) foram consideradas adequadas para diagnóstico. Resultados malignos foram mais frequentes nos pacientes com suspeita de lesão secundária e história de neoplasia maligna conhecida (p < 0,001) e nos procedimentos orientados pela PET/CT (p = 0,011). Conclusão: A biópsia percutânea guiada por TC é segura e eficaz no diagnóstico de lesões ósseas suspeitas.

Magnetic resonance imaging of the chest in the evaluation of cancer patients: state of the art

Magnetic resonance imaging (MRI) has several advantages in the evaluation of cancer patients with thoracic lesions, including involvement of the chest wall, pleura, lungs, mediastinum, esophagus and heart. It is a quite useful tool in the diagnosis, staging, surgical planning, treatment response evaluation and follow-up of these patients. In the present review, the authors contextualize the relevance of MRI in the evaluation of thoracic lesions in cancer patients. Considering that MRI is a widely available method with high contrast and spatial resolution and without the risks associated with the use of ionizing radiation, its use combined with new techniques such as cine-MRI and functional methods such as perfusion- and diffusion-weighted imaging may be useful as an alternative tool with performance comparable or complementary to conventional radiological methods such as radiography, computed tomography and PET/CT imaging in the evaluation of patients with thoracic neoplasias.

Performance and Methodological Aspects in Positron Emission Tomography

Performance standards for Positron emission tomography (PET) were developed to be able to compare systems from different generations and manufacturers. This resulted in the NEMA methodology in North America and the IEC in Europe. In practices, the NEMA NU 2- 2001 is the method of choice today. These standardized methods allow assessment of the physical performance of new commercial dedicated PET/CT tomographs. The point spread in image formation is one of the factors that blur the image. The phenomenon is often called the partial volume effect. Several methods for correcting for partial volume are under research but no real agreement exists on how to solve it. The influence of the effect varies in different clinical settings and it is likely that new methods are needed to solve this problem. Most of the clinical PET work is done in the field of oncology. The whole body PET combined with a CT is the standard investigation today in oncology. Despite the progress in PET imaging technique visualization, especially quantification of small lesions is a challenge. In addition to partial volume, the movement of the object is a significant source of error. The main causes of movement are respiratory and cardiac motions. Most of the new commercial scanners are in addition to cardiac gating, also capable of respiratory gating and this technique has been used in patients with cancer of the thoracic region and patients being studied for the planning of radiation therapy. For routine cardiac applications such as assessment of viability and perfusion only cardiac gating has been used. However, the new targets such as plaque or molecular imaging of new therapies require better control of the cardiac motion also caused by respiratory motion. To overcome these problems in cardiac work, a dual gating approach has been proposed. In this study we investigated the physical performance of a new whole body PET/CT scanner with NEMA standard, compared methods for partial volume correction in PET studies of the brain and developed and tested a new robust method for dual cardiac-respiratory gated PET with phantom, animal and human data. Results from performance measurements showed the feasibility of the new scanner design in 2D and 3D whole body studies. Partial volume was corrected, but there is no best method among those tested as the correction also depends on the radiotracer and its distribution. New methods need to be developed for proper correction. The dual gating algorithm generated is shown to handle dual-gated data, preserving quantification and clearly eliminating the majority of contraction and respiration movement

Clinically occult metastases in patients with cutaneous melanoma. Detection with sentinel lymph node biopsy and whole body positron emission tomography

Objective: The aim of this study was to investigate the use of sentinel lymph node biopsy (SLNB) and whole body positron emission tomography (PET), with emphasis on surgical treatment and prognosis, in the detection of clinically occult metastases in patients with clinically localized cutaneous melanoma. Patients and methods: The study population consisted of 1255 patients with clinical stage I–II cutaneous melanoma, operated at Turku University Hospital between 1983 and 2007. 334 patients underwent SLNB and they were compared to 921 retrospective patients. A subgroup of 30 symptom-free patients with high risk melanoma underwent prospectively whole body PET 6–24 months postoperatively. Results: Overall, the disease-specific survival rate was 84.4 % at five years. Sex, Breslow thickness, age and nodal status were independent prognostic factors for survival. SLNB revealed occult nodal metastases in 17 % of the patients. There was no significant difference in disease-specific overall survival between SLNB patients and controls, but the nodal disease-free time was significantly longer suggesting better local control after SLNB and subsequent completion lymph node dissection. The followup time was different between the study cohorts and initial surgery was performed during different time periods. SLNB detected micrometastases in seven of 155 patients (4.5 %) with thin T1 primary melanoma and in four of 25 patients (16 %) with head and neck melanoma. In six of 30 asymptomatic patients with high risk melanoma (20 %), whole body PET detected occult distant metastases. Conclusion: Both SLNB and whole body PET were reliable methods to detect clinically occult metastases in patients with cutaneous melanoma. This upstaging altered the treatment in each case.