Variations of the hepatic SUV in relation to the body mass index in whole body PET-CT studies

Author(s):  
S.M. Batallés ◽  
R.L. Villavicencio ◽  
A. Quaranta ◽  
L. Burgos ◽  
S. Trezzo ◽  
...  
2014 ◽  
Vol 42 (1) ◽  
pp. 62-67 ◽  
Author(s):  
R. Sanchez-Jurado ◽  
M. Devis ◽  
R. Sanz ◽  
J. E. Aguilar ◽  
M. d. Puig Cozar ◽  
...  

2020 ◽  
Author(s):  
Roberta Matheoud ◽  
Naema Al-Maymani ◽  
Alessia Oldani ◽  
Gian Mauro Sacchetti ◽  
Marco Brambilla ◽  
...  

Abstract BackgroundTime-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality in low counts acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on 18F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment. MethodsThe NEMA-IQ phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR), and body mass index (BMI). The phantom was filled with an average concentration of 5.3 kBq/mL of FDG solution and the spheres with TBR of 21.2, 8.8, and 5.0 in 3 different sessions. Images were acquired at varying background activity concentration from 5.1 to 1.3 kBq/mL and images were reconstructed for ESD of 30-151 seconds per bed position with and without Point Spread Function (PSF) correction. The parameters were all considered in a single analysis using multiple linear regression methods. ResultsAs expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and BMI of the phantom, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the weight of the patient and TBR of the lesion. ConclusionsAC and ESD proved to be effective tools in modulating CNR. ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.


Autism ◽  
2021 ◽  
pp. 136236132110443
Author(s):  
Hunter J Bennett ◽  
Taylor Jones ◽  
Kevin A Valenzuela ◽  
Justin A Haegele

Autistic persons exhibit variable movement, loading, and coordination patterns during walking. While much research has examined walking, little to no research exists regarding running for autistic persons despite its prevalence and benefits as a mode of physical activity. This study determined if autistic adolescents demonstrate increased coordination variability during running compared to matched controls. Seventeen autistic adolescents (aged = 13–18 years) and seventeen sex, age, and body mass index matched controls performed running at two matched speeds: self-selected of autistic adolescents and at 3.0 m/s. Modified vector coding was used to determine the patterns of movement for foot-shank, shank-thigh, left/right thigh, and contralateral arm-thigh coupling. Coordination variability, measuring cycle-to-cycle variability, was determined during loading response and pushoff phases. Mixed-model analyses of variance were used to determine group by speed interactions and main effects. Coordination variability was nearly 2× larger (all p < 0.001) in autistic adolescents compared to controls. Speed main effects were found for several sagittal plane couples during loading response. In agreement with walking analyses, this study illustrates that autistic adolescents run with increased intra-limb, inter-limb, and cross-body coordination variability. Like walking, increased coordination variability during running may negatively impact this mode of physical activity for autistic persons. Lay abstract Walking and running are popular forms of physical activity that involve the whole body (pelvis/legs and arms/torso) and are coordinated by the neuromuscular system, generally without much conscious effort. However, autistic persons tend not to engage in sufficient amounts of these activities to enjoy their health benefits. Recent reports indicate that autistic individuals tend to experience altered coordination patterns and increased variability during walking tasks when compared to non-autistic controls. Greater stride-to-stride coordination variability, when the task has not changed (i.e. walking at same speed and on same surface), is likely indicative of motor control issues and is more metabolically wasteful. To date, although, research examining running is unavailable in any form for this population. This study aimed to determine if coordination variability during running differs between autistic adolescents and age, sex, and body mass index matched non-autistic controls. This study found that increased variability exists throughout the many different areas of the body (foot-leg, left/right thighs, and opposite arm-opposite thigh) for autistic adolescents compared to controls. Along with previous research, these findings indicate autistic persons exhibit motor control issues across both forms of locomotion (walking and running) and at multiple speeds. These findings highlight issues with motor control that can be addressed by therapeutic/rehabilitative programming. Reducing coordination variability, inherently lessening metabolic inefficiency, may be an important step toward encouraging autistic youth to engage in sufficient physical activity (i.e. running) to enjoy physiological and psychological benefits.


2013 ◽  
Vol 38 (6) ◽  
pp. 407-412 ◽  
Author(s):  
Go Akamatsu ◽  
Katsuhiko Mitsumoto ◽  
Kaori Ishikawa ◽  
Takafumi Taniguchi ◽  
Nobuyoshi Ohya ◽  
...  

2021 ◽  
Vol 29 (4) ◽  
Author(s):  
Muhammad Nur Annuar Mohd Yunos ◽  
Mohd Azlis Sani Md Jalil ◽  
Nor Azali Azmir ◽  
Mifzal Nazhan Mazlan

Urban rail is a widely used public transportation; the vibration from frequent rides may impact passengers. The rail vehicle’s vibrations can cause human fatigue and result in severe musculoskeletal problems to the passenger. This paper aims to identify the effects of passenger orientation, operation time and body mass index on passengers’ whole-body vibration on an urban rail in Malaysia. Real-time monitoring of the whole-body vibration was conducted using 23 full factorial designs of the experiment, which was analysed statistically using Minitab Software. The overall result of this study is that the passengers in a seated position had greater exposure to whole-body vibration, which is 0.3686 ms-2 than standing passengers, 0.2965 ms-2. Also, passengers tend to be exposed to greater vibration during an off-peak time of 0.4063 ms-2, than a peak time of 0.3706 ms-2. Lastly, overweight passengers were exposed to greater vibration, of 0.4063 ms-2, than passengers within the ideal weight range of 0.4000 ms-2. This study has statistically proven that all the factors were significantly influenced the vibration exposure to the passenger. The most significant factor towards the vibration exposure is the “Body Mass Index (BMI)”, in which the p-value is less than 0.001. This study concludes that the whole-body vibration of a passenger is affected by the orientation of the passenger, operation time and body mass index of passengers on urban rail service.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Roberta Matheoud ◽  
Naema Al-Maymani ◽  
Alessia Oldani ◽  
Gian Mauro Sacchetti ◽  
Marco Brambilla ◽  
...  

Abstract Background Time-of-flight (TOF) PET technology determines a reduction in the noise and improves the reconstructed image quality in low count acquisitions, such as in overweight patients, allowing a reduction of administered activity and/or imaging time. However, international guidelines and recommendations on the 18F-fluoro-2-deoxyglucose (FDG) activity administration scheme are old or only partially account for TOF technology and advanced reconstruction modalities. The aim of this study was to optimize FDG whole-body studies on a TOF-PET/CT scanner by using a multivariate approach to quantify how physical figures of merit related to image quality change with acquisition/reconstruction/patient-dependent parameters in a phantom experiment. Methods The NEMA-IQ phantom was used to evaluate contrast recovery coefficient (CRC), background variability (BV) and contrast-to-noise ratio (CNR) as a function of changing emission scan duration (ESD), activity concentration (AC), target internal diameter (ID), target-background activity ratio (TBR) and body mass index (BMI). The phantom was filled with an average concentration of 5.3 kBq/ml of FDG solution and the spheres with TBR of 21.2, 8.8 and 5.0 in 3 different sessions. Images were acquired at varying background activity concentration from 5.1 to 1.3 kBq/ml, and images were reconstructed for ESD of 30–151 s per bed position with and without point spread function (PSF) correction. The parameters were all considered in a single analysis using multiple linear regression methods. Results As expected, CRC depended only on sphere ID and on PSF application, while BV depended on sphere ID, ESD, AC and BMI of the phantom, in order of decreasing relevance. Noteworthy, ESD and AC resulted as the most significant predictors of CNR variability with a similar relevance, followed by the BMI of the patient and TBR of the lesion. Conclusions AC and ESD proved to be effective tools in modulating CNR. ESD could be increased rather than AC to improve image quality in overweight/obese patients to fulfil ALARA principles.


Author(s):  
Michele Polfuss ◽  
Bethany Forseth ◽  
Dale A. Schoeller ◽  
Chiang-Ching Huang ◽  
Andrea Moosreiner ◽  
...  

PURPOSE: To identify the accuracy of Body Mass Index (BMI) to categorize body weight in a sample of children with spina bifida and Down syndrome as compared to typically developing peers. METHODS: A secondary analysis of 32 children with spina bifida, Down syndrome or no chronic illness. A calculated BMI was plotted on the Centers for Disease Control and Prevention age- and sex-specific BMI growth charts to determine each child’s weight status. Percentage of body fat, obtained by labeled water, was plotted on two different body fat percentile reference curves, one derived from a whole body measure (DXA) of body fat and one by skin-fold measure. Differences in weight categories between calculated BMI and body fat percentile curves were reported. RESULTS: The calculated BMI for children with a disability had significant misclassifications as a screening tool for body fat when compared to children without a disability. Misclassifications were increased with the body fat percentile reference curve derived from skin-fold measures and for children who primarily used a wheelchair. CONCLUSION: The current recommendation to use BMI to categorize weight status is not useful for many children with disabilities. Further research to identify an alternative pragmatic strategy is necessary.


2007 ◽  
Vol 177 (4S) ◽  
pp. 64-64
Author(s):  
Murugesan Manoharan ◽  
Martha A. Reyes ◽  
Alan M. Nieder ◽  
Bruce R. Kava ◽  
MarkS Soloway

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