292 research outputs found
Incidental Monotypic (Fat-Poor) Renal Angiomyolipoma Diagnosed by Core Needle Biopsy
We present the case of a 55-year-old patient with a history of chemotherapy and bone marrow transplantation because of acute myeloid leukaemia. An incidental 4 × 3 cm measuring renal mass was detected while performing a magnetic resonance imaging (MRI) for lumbago. The lesion was suspected to be either a renal cell carcinoma (RCC) or a leukemic infiltration. To decide about further treatment a percutaneous core needle biopsy was performed. Histology showed a monotypic angiomyolipoma, a relatively rare benign renal lesion. Interestingly, in cross-sectional imaging, angiomyolipoma was not taken into differential diagnostic account because of lack of a fatty component. Due to bleeding after biopsy the feeding artery of the tumor was occluded by microcoils. This case demonstrates the utility of biopsy of renal tumors, in particular when small tumor-like lesions are incidentally detected to decide about the right treatment and thereby avoiding nephrectomy
Impact of velocity- and acceleration-compensated encodings on signal dropout and black-blood state in diffusion-weighted magnetic resonance liver imaging at clinical TEs.
PurposeThe study aims to develop easy-to-implement concomitant field-compensated gradient waveforms with varying velocity-weighting (M1) and acceleration-weighting (M2) levels and to evaluate their efficacy in correcting signal dropouts and preserving the black-blood state in liver diffusion-weighted imaging. Additionally, we seek to determine an optimal degree of compensation that minimizes signal dropouts while maintaining blood signal suppression.MethodsNumerically optimized gradient waveforms were adapted using a novel method that allows for the simultaneous tuning of M1- and M2-weighting by changing only one timing variable. Seven healthy volunteers underwent diffusion-weighted magnetic resonance imaging (DWI) with five diffusion encoding schemes (monopolar, velocity-compensated (M1 = 0), acceleration-compensated (M1 = M2 = 0), 84%-M1-M2-compensated, 67%-M1-M2-compensated) at b-values of 50 and 800 s/mm2 at a constant echo time of 70 ms. Signal dropout correction and apparent diffusion coefficients (ADCs) were quantified using regions of interest in the left and right liver lobe. The blood appearance was evaluated using two five-point Likert scales.ResultsSignal dropout was more pronounced in the left lobe (19%-42% less signal than in the right lobe with monopolar scheme) and best corrected by acceleration-compensation (8%-10% less signal than in the right lobe). The black-blood state was best with monopolar encodings and decreased significantly (p ConclusionAll of the diffusion encodings used in this study demonstrated suitability for routine DWI application. The results indicate that a perfect value for the level of M1-M2-compensation does not exist. However, among the examined encodings, the 84%-M1-M2-compensated encodings provided a suitable tradeoff
Effects of whole-body electromyostimulation with different impulse intensity on blood pressure changes in hyper- and normotensive overweight people. A pilot study
Hypertension is a frequent condition in untrained middle-aged to older adults, who form the core group of whole-body electromyostimulation (WB-EMS) applicants. So far, the acute effects of varying impulse intensities on blood pressure responses have not been evaluated in normo- and hypertensive people. Thirteen hypertensive and twelve normotensive overweight WB-EMS novices, 40–70 years old, conducted the same WB-EMS protocol (20 min, bipolar, 85 Hz, 350 µs, 4 s impulse-4 s rest; combined with easy movements) with increasing impulse intensity (low, moderate, advanced) per session. Mean arterial blood pressure (MAP) as determined by automatic sphygmomanometry rose significantly (p < .001) from rest, 5 min pre-WB-EMS to immediately pre-WB-EMS assessment. Of importance, a 20-min WB-EMS application does not increase MAP further. In detail, maximum individual MAP does not exceed 128 mmHg (177 mmHg systolic or 110 mmHg diastolic) in any case. Two-min post-WB-EMS, MAP was significantly lower (p = .016) compared to immediately pre-WB-EMS. In contrast, heart rate increased significantly from immediately pre to immediately post-exercise (p < .001), though individual peak values did not exceed 140 beats/min−1 and heart rate decreased rapidly (p < .001) post-exercise. No significant differences in MAP and HR kinetics were observed for impulse intensity categories or hypertensive status. In summary, largely independently of impulse intensity and status, the acute effect of WB-EMS on MAP in novice applicants seem to be largely negligible. Although definite evidence might not have been provided by the present study, we conclude that hypertension, at least under treatment, should not be considered as a barrier for WB-EMS application in moderately old or older cohorts
Deep learning for brain metastasis detection and segmentation in longitudinal MRI data
Brain metastases occur frequently in patients with metastatic cancer. Early
and accurate detection of brain metastases is very essential for treatment
planning and prognosis in radiation therapy. To improve brain metastasis
detection performance with deep learning, a custom detection loss called
volume-level sensitivity-specificity (VSS) is proposed, which rates individual
metastasis detection sensitivity and specificity in (sub-)volume levels. As
sensitivity and precision are always a trade-off in a metastasis level, either
a high sensitivity or a high precision can be achieved by adjusting the weights
in the VSS loss without decline in dice score coefficient for segmented
metastases. To reduce metastasis-like structures being detected as false
positive metastases, a temporal prior volume is proposed as an additional input
of DeepMedic. The modified network is called DeepMedic+ for distinction. Our
proposed VSS loss improves the sensitivity of brain metastasis detection for
DeepMedic, increasing the sensitivity from 85.3% to 97.5%. Alternatively, it
improves the precision from 69.1% to 98.7%. Comparing DeepMedic+ with DeepMedic
with the same VSS loss, 44.4% of the false positive metastases are reduced in
the high sensitivity model and the precision reaches 99.6% for the high
specificity model. The mean dice coefficient for all metastases is about 0.81.
With the ensemble of the high sensitivity and high specificity models, on
average only 1.5 false positive metastases per patient needs further check,
while the majority of true positive metastases are confirmed. The ensemble
learning is able to distinguish high confidence true positive metastases from
metastases candidates that require special expert review or further follow-up,
being particularly well-fit to the requirements of expert support in real
clinical practice.Comment: Implementation is available to public at
https://github.com/YixingHuang/DeepMedicPlu
Análise de timol em cera de abelha por micro-extracção em fase sólida (SPME)
A aplicação contínua de acaricídas lipofílicos sintéticos no tratamento das
abelhas conduz a uma acumulação que depende da frequência, lipofilicidade e
quantidade de princípio activo utilizada. Este efeito é mais acentuado na cera
de abelha que no mel, no entanto, e porque a persistência destes resíduos é
elevada, provoca o aparecimento de resistências e a perda do seu efeito
acaricida.[1] Esta razão levou à pesquisa de outros compostos alternativos não
tóxicos e não persistentes, com efeito sobre o ácaro das abelhas, Varroa
Jacobsoni. Entre estes compostos encontra-se o timol, um composto fenólico,
volátil, presente no tomilho. Dos diversos componentes dos óleos essenciais
este é sem dúvida o que demonstrou maior efeito acaricida, utilizando-se no
tratamento das abelhas directamente ou como componente de diversas
formulações.[2] Em Portugal, foi introduzido muito recentemente sob a forma
comercial de APIGUARD: um gel, à base de timol, que controla termicamente a
libertação do princípio activo.
O controlo dos resíduos de timol na cera de abelha e no mel é assim um
desafio actual quer do ponto de vista sanitário quer de qualidade alimentar.
A micro-extracção em fase sólida (SPME) é uma técnica de preparação de
amostras que se baseia na sorção de analítos no revestimento de uma fibra de
sílica fundida e posterior desorção térmica no injector de um cromatógrafo em
fase gasosa (GC). Para além de combinar num único processo etapas de
extracção, purificação e concentração dos analitos, a técnica de SPME
apresenta uma série de vantagens relativamente às técnicas de extracção
convencionais, como a extracção líquido-líquido e extracção em fase sólida,
nomeadamente a sua relativa simplicidade e rapidez, reduzido custo e não
utilização de solventes para a extracção de analitos, para além de permitir a
extracção por imersão directa na amostra gasosa ou líquida e extracção por
amostragem do espaço-de-cabeça da amostra líquida ou sólida.[3] Ao contrário
das técnicas tradicionais, que permitem uma extracção quantitativa dos
analitos, a técnica de SPME baseia-se num equilíbrio de partição do analito.
Esta particularidade torna a técnica de SPME bastante sensível a parâmetros
experimentais que possam afectar os coeficientes de partição dos analitos e,
consequentemente, a sensibilidade e reprodutibilidade dos resultados.[4]
O objectivo deste trabalho é o desenvolvimento de uma metodologia para a
análise de timol em ceras contaminadas, utilizando como padrão interno a
benzofenona. Em primeiro lugar, procedeu-se à optimização da técnica através
da determinação da quantidade de cera, temperatura de análise e período de
contacto da fibra com o espaço-de-cabeça da amostra mais adequados para o
caso em estudo. Numa segunda fase, procedeu-se à análise de diversas
lâminas de cera contaminadas propositadamente com timol e sujeitas a
diferentes condições de armazenamento: em frio, ao ar e em estufa.
Finalmente, procedeu-se à construção da curva de calibração e quantificação
do timol presente nas diversas amostras de cera analisadas.
Considerando-se os resultados, para os níveis de contaminação avaliados, as
condições analíticas mais adequadas ocorrem com a utilização de 1 g de cera,
mantendo-se a fibra em contacto com o espaço-de-cabeça durante 40 minutos
a uma temperatura de 60 ºC. Nestas condições experimentais foi possível obter
uma boa correlação linear (r2=0,990) no intervalo de concentrações [3,5-14
mg/g]. A quantidade de timol encontrada nas amostras é significativamente
inferior à colocada durante o processo de fabrico das lâminas, pelo que o
processo de conservação não é o mais adequado, sendo evidente uma menor
quantidade de timol quando a lâmina de cera é colocada na estufa
From red to white urine: a patient's nightmare with a rather benign outcome
<p>Abstract</p> <p>Background</p> <p>Chyluria is a medical condition with presence of chyle in the urine. The disease is most prevalent in endemic regions of Africa and the Indian subcontinent where it is mostly caused by parasitic infections, particularly lymphatic filariasis due to wucheria bancrofti. Non-parasitic chyluria, however, is a very rare finding.</p> <p>Case Presentation</p> <p>We report the case of a 48 year old woman who developed a lymphorenal fistula with chyluria following ureterrenoscopy with biopsies taken for urological work-up of persistent macrohematuria. Renal biopsy confirmed the diagnosis of benign familial hematuria due to thin basement nephropathy, a condition frequently associated with episodes of macrohematuria.</p> <p>Conclusions</p> <p>This case highlights a rare case of non-parasitic chyluria as a complication of urological work-up for macrohematuria of benign nature.</p
3T vs. 7T fMRI: capturing early human memory consolidation after motor task utilizing the observed higher functional specificity of 7T
ObjectiveFunctional magnetic resonance imaging (fMRI) visualizes brain structures at increasingly higher resolution and better signal-to-noise ratio (SNR) as field strength increases. Yet, mapping the blood oxygen level dependent (BOLD) response to distinct neuronal processes continues to be challenging. Here, we investigated the characteristics of 7 T-fMRI compared to 3 T-fMRI in the human brain beyond the effect of increased SNR and verified the benefits of 7 T-fMRI in the detection of tiny, highly specific modulations of functional connectivity in the resting state following a motor task.Methods18 healthy volunteers underwent two resting state and a stimulus driven measurement using a finger tapping motor task at 3 and 7 T, respectively. The SNR for each field strength was adjusted by targeted voxel size variation to minimize the effect of SNR on the field strength specific outcome. Spatial and temporal characteristics of resting state ICA, network graphs, and motor task related activated areas were compared. Finally, a graph theoretical approach was used to detect resting state modulation subsequent to a simple motor task.ResultsSpatial extensions of resting state ICA and motor task related activated areas were consistent between field strengths, but temporal characteristics varied, indicating that 7 T achieved a higher functional specificity of the BOLD response than 3 T-fMRI. Following the motor task, only 7 T-fMRI enabled the detection of highly specific connectivity modulations representing an “offline replay” of previous motor activation. Modulated connections of the motor cortex were directly linked to brain regions associated with memory consolidation.ConclusionThese findings reveal how memory processing is initiated even after simple motor tasks, and that it begins earlier than previously shown. Thus, the superior capability of 7 T-fMRI to detect subtle functional dynamics promises to improve diagnostics and therapeutic assessment of neurological diseases
- …