Preliminary comparative study of cortical thickness in HIV-infected patients with and without working memory deficit.

PURPOSE: Changes in cerebral cortical regions occur in HIV-infected patients, even in those with mild neurocognitive disorders. Working memory / attention is one of the most affected cognitive domain in these patients, worsening their quality of life. Our objective was to assess whether cortical thickness differs between HIV-infected patients with and without working memory deficit. METHODS: Forty-one adult HIV-infected patients with and without working memory deficit were imaged on a 1.5 T scanner. Working memory deficit was classified by composite Z scores for performance on the Digits and Letter-Number Sequencing subtests of the Wechsler Adult Intelligence Scale (third edition; WAIS-III). Cortical thickness was determined using FreeSurfer software. Differences in mean cortical thickness between groups, corrected for multiple comparisons using Monte-Carlo simulation, were examined using the query design estimate contrast tool of the FreeSurfer software. RESULTS: Greater cortical thickness in left pars opercularis of the inferior frontal gyrus, and rostral and caudal portions of the left middle frontal gyrus (cluster 1; p = .004), and left superior frontal gyrus (cluster 2; p = .004) was observed in HIV-infected patients with working memory deficit compared with those without such deficit. Negative correlations were found between WAIS-III-based Z scores and cortical thickness in the two clusters (cluster 1: ρ = -0.59; cluster 2: ρ = -0.47). CONCLUSION: HIV-infected patients with working memory deficit have regions of greater thickness in the left frontal cortices compared with those without such deficit, which may reflect increased synaptic contacts and/or an inflammatory response related to the damage caused by HIV infection.

Prone Myocardial Perfusion Imaging and Breast Attenuation: A Phantom Study.

BACKGROUND: Soft tissue attenuation artifacts are the most common cause of misinterpretation in myocardial perfusion Imaging (MPI). Few studies assessing the value of prone imaging in women have been published. Breast attenuation artifacts can be present in up to 40% of the MPI studies in women. OBJECTIVES: This study aimed at evaluating the potential impact of prone MPI on breast attenuation, with a critical analysis of activity optimization and breast size influence. METHODS: MPI of an Anthropomorphic Torso Phantom with silicone breast prostheses and equivalent adipose tissue was compared to a standard MPI database. RESULTS: A medical qualitative and semiquantitative analysis demonstrated higher uptake in the LV anterior segments in the prone position for all injected activities. An artificial myocardium lesion was diagnosable in the right segment in all images, which shows that prone positioning would not mask a true lesion and it assists the cardiologist with a more accurate analysis. These results showed that it is possible to optimize the activity to be injected by up to 55.6% when using combined supine-prone images. CONCLUSION: Prone position has a high impact on the interpretation of MPI in female patients since it reduces the breast attenuation artifacts, and optimizes the radiation protection of the patient and all staff involved in the procedure, making it more cost-effective.

Pilot study of brain morphometry in a sample of Brazilian children with attention deficit hyperactivity disorder: influence of clinical presentation.

PURPOSE: Currently, the diagnosis of attention deficit hyperactivity disorder (ADHD) rests on clinical criteria. Nonetheless, neuroimaging studies have demonstrated that children with ADHD have different cortical thickness and volume measures to typically developing children (TDC). In general, studies do not evaluate the influence of clinical presentation in the brain morphometry of ADHD children. Our objective was to perform a pilot study in order to evaluate cortical thickness and brain volume in a sample of Brazilian ADHD children and compare these to those of TDC, taking into account the influence of clinical presentation. METHODS: We performed an analytic study comparing 17 drug-naïve ADHD children of both genders, aged between 7 and 10, and 16 TDC. ADHD subjects were first considered as one group and further separated based on clinical presentation. RESULTS: The brain volume did not differ between patients and TDC. Smaller cortical thicknesses were identified on the left superior, medium and inferior temporal cortex, as well as in the left inferior parietal cortex. When compared to TDC, combined and inattentive ADHD presentations depicted smaller cortical thickness with high significance and power. The same magnitude of results was not observed when comparing inattentive ADHD and TDC. CONCLUSIONS: In this pilot study, ADHD is associated with abnormalities involving the cortical thickness of the posterior attentional system. The cortical thickness in the left superior, medium and inferior temporal cortex, as well as in the left inferior parietal cortex may differ according to ADHD presentations.

Working memory and left medial temporal cortical thickness.

OBJECTIVE: To perform a pilot study to investigate the association between working memory and cortical thickness in a sample of attention deficit/hyperactivity disorder (ADHD) children. METHODS: Seventeen children aged 7-10 years diagnosed with ADHD and 16 healthy children underwent a magnetic resonance scan for cortical thickness measurements. Data was correlated with working memory performance using the Backwards Digit Span subtest of the Wechsler Intelligence Scale for Children. RESULTS: Working memory impairment, evidenced by lower scores on the Backwards Digit Span, was observed in patients with ADHD compared to healthy controls. There was a direct correlation between working memory and cortical thickness of the left medial temporal lobe (Spearman's correlation coefficient: 0.499; p < 0.005). CONCLUSIONS: Our data suggests, for the first time, a correlation between working memory, evaluated by the Backwards Digit Span, and left medial temporal cortical thickness.

Working memory and left medial temporal cortical thickness / Memória de trabalho e espessura cortical temporal medial esquerda

ABSTRACT Objective To perform a pilot study to investigate the association between working memory and cortical thickness in a sample of attention deficit/hyperactivity disorder (ADHD) children. Methods Seventeen children aged 7-10 years diagnosed with ADHD and 16 healthy children underwent a magnetic resonance scan for cortical thickness measurements. Data was correlated with working memory performance using the Backwards Digit Span subtest of the Wechsler Intelligence Scale for Children. Results Working memory impairment, evidenced by lower scores on the Backwards Digit Span, was observed in patients with ADHD compared to healthy controls. There was a direct correlation between working memory and cortical thickness of the left medial temporal lobe (Spearman’s correlation coefficient: 0.499; p < 0.005). Conclusions Our data suggests, for the first time, a correlation between working memory, evaluated by the Backwards Digit Span, and left medial temporal cortical thickness.

RESUMO Objetivo Realizar estudo piloto para investigar a associação entre memória de trabalho e espessura cortical em crianças com transtorno de défict de atenção e hiperatividade (TDAH). Métodos Dezessete crianças com TDAH, entre 7 e 10 anos, e dezesseis crianças saudáveis foram submetidas a ressonância magnética para aferição de espessura cortical. Os dados foram correlacionados com desempenho da memória de trabalho usando a ordem inversa do subteste Dígitos da Escala de Inteligência Wechsler para Crianças. Resultados Prejuízos na memória de trabalho, evidenciado pela menor pontuação na ordem inversa do subteste Dígitos, foram observados em pacientes com TDAH, em comparação com crianças saudáveis. Observou-se correlação direta entre memória de trabalho e espessura do lobo temporal médio à esquerda (coeficiente de correlação de Spearman: 0,499; p < 0,005). Conclusões Nossos dados sugerem, pela primeira vez, uma correlação entre memória de trabalho, avaliada através da pontuação na ordem inversa do subteste Dígitos, e espessura do córtex temporal medial à esquerda.

Estudo de otimização de protocolo em cintilografia de perfusão miocárdica com a utilização de um simulador antropomórfico / Optimization of a protocol for myocardial perfusion scintigraphy by using an anthropomorphic phantom

Objetivo: Realizar um estudo de otimização de exames de cintilografia de perfusão miocárdica. Materiais e Métodos: Foram adquiridas imagens de um objeto simulador antropomórfico de tórax contendo coração, pulmões, fígado e coluna vertebral, em uma gama câmara SPECT GE modelo Ventri, utilizando-se diferentes atividades e variando-se os tempos de aquisição, de forma a verificar a influência destes parâmetros na qualidade da imagem clínica reconstruída. Foi utilizado o radiofármaco 99mTc-sestamibi e os testes realizados foram avaliados clinicamente a partir de notas, tanto para o summed stress score quanto para a qualidade técnica da imagem e perfusão. As quantificações foram realizadas pelo software ImageJ. Resultados: Os resultados demonstraram que, para o tempo padrão utilizado na realização dos exames de 15 segundos por ângulo, a atividade injetada poderia ser reduzida em 33,34%. Além disso, se o tempo usual de exame for reduzido em 54,34% (7 segundos por ângulo), ainda assim a atividade padrão injetada poderia ser reduzida em 16,67%, sem prejudicar a qualidade da imagem e a confiabilidade do diagnóstico. Conclusão: O método desenvolvido e os resultados obtidos podem ser utilizados para o desenvolvimento de um estudo clínico de pacientes em um protocolo otimizado. .

Objective: To develop a study aiming at optimizing myocardial perfusion imaging. Materials and Methods: Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The 99mTc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. Results: The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. Conclusion: The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol. .

Cuneus and fusiform cortices thickness is reduced in trigeminal neuralgia.

BACKGROUND: Chronic pain disorders are presumed to induce changes in brain grey and white matters. Few studies have focused CNS alterations in trigeminal neuralgia (TN). METHODS: The aim of this study was to explore changes in white matter microstructure in TN subjects using diffusion tensor images (DTI) with tract-based spatial statistics (TBSS); and cortical thickness changes with surface based morphometry. Twenty-four patients with classical TN (37-67 y-o) and 24 healthy controls, matched for age and sex, were included in the study. RESULTS: Comparing patients with controls, no diffusivity abnormalities of brain white matter were detected. However, a significant reduction in cortical thickness was observed at the left cuneus and left fusiform cortex in the patients group. The thickness of the fusiform cortex correlated negatively with the carbamazepine dose (p = 0.023). CONCLUSIONS: Since the cuneus and the fusiform gyrus have been related to the multisensory integration area and cognitive processing, as well as the retrieval of shock perception conveyed by Aδ fibers, our results support the role of these areas in TN pathogenesis. Whether such changes occurs as an epiphenomenon secondary to daily stimulation or represent a structural predisposition to TN in the light of peripheral vascular compression is a matter of future studies.

Optimization of a protocol for myocardial perfusion scintigraphy by using an anthropomorphic phantom.

OBJECTIVE: To develop a study aiming at optimizing myocardial perfusion imaging. MATERIALS AND METHODS: Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The (99m)Tc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. RESULTS: The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. CONCLUSION: The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol.

OBJETIVO: Realizar um estudo de otimização de exames de cintilografia de perfusão miocárdica. MATERIAIS E MÉTODOS: Foram adquiridas imagens de um objeto simulador antropomórfico de tórax contendo coração, pulmões, fígado e coluna vertebral, em uma gama câmara SPECT GE modelo Ventri, utilizando-se diferentes atividades e variando-se os tempos de aquisição, de forma a verificar a influência destes parâmetros na qualidade da imagem clínica reconstruída. Foi utilizado o radiofármaco 99mTc-sestamibi e os testes realizados foram avaliados clinicamente a partir de notas, tanto para o summed stress score quanto para a qualidade técnica da imagem e perfusão. As quantificações foram realizadas pelo software ImageJ. RESULTADOS: Os resultados demonstraram que, para o tempo padrão utilizado na realização dos exames de 15 segundos por ângulo, a atividade injetada poderia ser reduzida em 33,34%. Além disso, se o tempo usual de exame for reduzido em 54,34% (7 segundos por ângulo), ainda assim a atividade padrão injetada poderia ser reduzida em 16,67%, sem prejudicar a qualidade da imagem e a confiabilidade do diagnóstico. CONCLUSÃO: O método desenvolvido e os resultados obtidos podem ser utilizados para o desenvolvimento de um estudo clínico de pacientes em um protocolo otimizado.

In vivo evaluation of cortical thickness with magnetic resonance imaging in patients with bipolar disorder

Changes in cortical thickness can be related to neuropsychiatric disorders and neurodegenerative processes. Previous studies have been conducted to characterize the pattern of changes in cortical thickness in several psychiatric diseases. The aim of the present study was to evaluate changes in cortical thickness with magnetic resonance imaging (MRI) in patients with bipolar disorder. Twenty-seven patients with bipolar disorder (14 male, 36.0 ± 16.2 years old; 13 female, 41.6 ± 10.7 years old) and 40 healthy controls (16 male, 36.0 ± 10.5 years old; 24 female, 37.0 ± 4.7 years old) underwent 3T MRI. Sagittal T1-weighted magnetization prepared rapid acquisition gradient echo images were acquired (voxel size, 1.33 mm³; 128 slices; in-plane matrix resolution, 256 × 256; flip angle, 7º; repetition time, 2530 ms; echo time, 3.39 ms; inversion time, 1100 ms). Cortical segmentation was performed using FreeSurfer 4.0.5. The results indicated both thinning and thickening of the cerebral cortex in patients with bipolar disorder compared with controls, depending on gender. Significant (p < .01) thickening was observed in the right hemisphere superior-parietal cortex in female patients with bipolar disorder, and significant (p < .05) thinning was observed in the left hemisphere caudal-anterior cingulate in male patients with bipolar disorder. The other regions did not show significant differences. The results suggest that an analysis of cortical thickness with MRI in patients with bipolar disorder may allow identification of areas that may be morphologically changed compared with controls. Demonstration of these alterations will elucidate the pathophysiology of bipolar disorder and may contribute to better therapies for this disorder.

Oral and pharyngeal transit of a paste bolus in Chagas' disease.

We measured the oral and pharyngeal transit of a paste bolus in 20 patients with Chagas' disease and 21 controls. Each subject swallowed of a 10-ml paste bolus prepared with 50 ml of water and 4.5 g of instant food thickener labeled with 55.5 MBq of 99m technetium phytate. After the scintigraphic recording of the transit, we delineated regions of interest (ROI) corresponding to mouth, pharynx, and proximal esophagus. Time-activity curves were generated for each ROI. There was no difference between patients with Chagas' disease and controls with respect to the duration of oral and pharyngeal transit, amount of pharyngeal residue, or flux of bolus entry into the proximal esophagus. The amount of oral residue was higher in patients with Chagas' disease (median = 0.71 ml) than in controls (median = 0.45 ml). The pharyngeal clearance duration was longer in patients with Chagas' disease (median = 0.85 s) than in controls (median = 0.60 s). The oral transit duration of the patients with Chagas' disease and dysphagia (median = 0.55 s, n = 14) was shorter than the oral transit duration of chagasic patients without dysphagia (median = 0.80 s, n = 6). We conclude that when swallowing a paste bolus, patients with Chagas' disease may have an increased amount of oral residue and a longer pharyngeal clearance duration than asymptomatic volunteers.

Trânsito de bolo pastoso pelo esôfagode pacientes com doença de Chagas / Esophageal transit of paste bolus in patients with Chagas disease

Estudou-se pelo método cintilográfico o trân»sito de bolo pastoso pelo esôfago de 20 pacien»tes com doença de Chagas e 21 controles. Os sujeitos realizaram deglutição única, sentados, de 10ml de bolo pastoso preparado com 4,5g de engrossante alimentar (Thick & Easy) diluído em 50ml de água, em frente do colimador do apa»relho de medicina nuclear, com registro de 20 imagens por segundo durante 20 segundos. O trânsito pelo esôfago foi analisado após defini»ção de regiões de interesse referentes às partes proximal, média e distal do órgão. Em 14 de 21controles (67,7%) e em 15 de 20 pacientes (75%) houve retenção total do bolo em parte proximal do esôfago. Não houve diferença entre contro»les (mediana: O,75s) e pacientes (mediana: O,55s) quanto ao tempo de entrada do bolo em parte proximal do esôfago. Nos sete controles e cinco pacientes em quem o bolo passou a parte proxi»mal do esôfago, a depuração (controles: 2,90s, pacientes: l,65s) e o trânsito (controles: l,90s, pacientes: O,85s) foram mais rápidos nos com doença de Chagas, com significância estatística apenas para a depuração. Os controles que tive»ram retenção do bolo em parte proximal não referiram disfagia. Os autores concluem que os resultados sugerem que a passagem do bolo pas»toso pela parte proximal do esôfago é mais rápi»da nos pacientes com doença de Chagas do que em controles, grande número de sujeitos tendo retenção do bolo em parte proximal quando exe-cutam apenas uma deglutição.