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1.
J Manipulative Physiol Ther ; 42(7): 541-550, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31864437

RESUMO

OBJECTIVE: The purpose of this study was to systematically review the literature regarding which condition (task, position, or contraction type), changes in muscle thickness could be interpreted as muscle activity of trunk muscles. METHODS: Studies that assessed the correlation between changes in muscle thickness measured with ultrasonography (US) and electromyography (EMG) activity were included. Only the data related to abdominal and lumbar trunk muscles in participants with or without low back pain were extracted. The PubMed, ScienceDirect, Ovid MEDLINE, Scopus, Springer, and Cumulative Index to Nursing and Allied Health Literature databases were searched from inception to August 2018. Two independent raters appraised the quality of the included studies using the Critical Appraisal Skills Program checklist. RESULTS: Fourteen studies were included. The results revealed significant correlations between US and EMG measures for the lumbar multifidus and erector spinae muscle during most contraction levels and postures. For transverse abdominis and internal oblique, US and EMG measures were correlated during low load abdominal drawing or bracing. The correlations were influenced by trunk position for higher intensities of contraction. For the external oblique muscle, correlation was observed only during trunk rotation. CONCLUSION: Changes in muscle thickness should not be interpreted as muscle activity for all tasks, positions, and contraction types. Only during prime movement tasks performed with isometric contraction could muscle thickness change be considered as muscle activity. Also, upright postures influenced the relationship between changes in muscle thickness and muscle activity for abdominal muscles.


Assuntos
Músculos Abdominais/diagnóstico por imagem , Dor Lombar/diagnóstico por imagem , Tronco/diagnóstico por imagem , Abdome/diagnóstico por imagem , Músculos Abdominais/fisiologia , Feminino , Humanos , Contração Isométrica/fisiologia , Região Lombossacral/diagnóstico por imagem , Masculino , Postura , Tronco/fisiologia , Ultrassonografia
2.
PLoS One ; 14(11): e0225413, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31743360

RESUMO

The present study aimed to examine the sizes of trunk and gluteus muscles in long jumpers and its relation to long jump performance. Twenty-three male long jumpers (personal best record in long jump: 653-788 cm) and 22 untrained men participated in the study. T1-weighted magnetic resonance images of the trunk and hip were obtained to determine the cross-sectional areas of the rectus abdominis, internal and external obliques and transversus abdominis, psoas major, quadratus lumborum, erector spinae and multifidus, iliacus, gluteus maximus, and gluteus medius and minimus. The cross-sectional areas of individual trunk and gluteus muscles relative to body mass were significantly larger in the long jumpers than in untrained men (P < 0.001, Cohen's d = 1.3-4.3) except for the gluteus medius and minimus. The relative cross-sectional area of the rectus abdominis of takeoff leg side was significantly correlated with their personal best record for the long jump (r = 0.674, corrected P = 0.004). Stepwise multiple regression analysis selected relative cross-sectional areas of the rectus abdominis and iliacus and the personal best record in 100-m sprint to predict the long jump distance (standard error of estimate = 22.6 cm, adjusted R2 = 0.763). The results of the multiple regression analysis demonstrated that the rectus abdominis and iliacus size were associated with long jump performance independently of sprint running capacity, suggesting the importance of these muscles in achieving high performance in the long jump.


Assuntos
Desempenho Atlético , Tronco/fisiologia , Peso Corporal , Quadril/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Tronco/diagnóstico por imagem , Adulto Jovem
3.
Spine Deform ; 7(6): 962-970, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31732009

RESUMO

STUDY DESIGN: Cross-sectional and longitudinal retrospective study. OBJECTIVES: To measure thoracic dimensions and volume during growth in early-onset idiopathic scoliosis (EOIS) patients and to compare them to a population of asymptomatic adults and to the previous literature. SUMMARY OF BACKGROUND DATA: Data on trunk growth for scoliotic children between 6 and 14 years of age is sparse in the literature. METHODS: Thirty-six patients (29 girls and 7 boys, between 3 and 14 years old, average Cobb angle 33°±15°) were included, all with a minimum two-year follow-up. Sixty-one asymptomatic girls and 54 asymptomatic adults were included as control groups. All subjects underwent biplanar radiography and 3D reconstruction of the spine, pelvis, and rib cage. EOIS patients repeated their radiologic examination every six months. Cobb angle, rib cage volume, anteroposterior and transverse diameters, thoracic index, thoracic perimeter, pelvic incidence, and T1-T12 and T1-S1 distance were calculated. Reproducibility of measurement was assessed. RESULTS: Measurement reliability in such young patients was comparable to previous studies in adolescents and adults. Geometrical parameters of EOIS patients increased linearly with age. For instance, rib cage volume in girls with EOIS increased from 2200 cm3 at six to seven years of age to 4100 cm3 at 13-14 years (65% of adult values, 294 cm3/y). Comparison with asymptomatic girls showed that EOIS could affect growth spurt. Longitudinal analysis on a cohort of six girls who had a follow-up of six years confirmed the cross-sectional data. CONCLUSIONS: In this longitudinal and cross-sectional study, trunk growth between 3 and 14 years of age was characterized, for the first time, with biplanar radiography and 3D reconstruction. The results can be useful to estimate patient growth and thus have potential application in the surgical planning of EOIS patients. LEVEL OF EVIDENCE: Level II, retrospective study.


Assuntos
Radiografia/instrumentação , Escoliose/diagnóstico por imagem , Vértebras Torácicas/diagnóstico por imagem , Tronco/crescimento & desenvolvimento , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Seguimentos , Humanos , Imageamento Tridimensional/métodos , Estudos Longitudinais , Masculino , Pelve/anatomia & histologia , Pelve/diagnóstico por imagem , Radiografia/métodos , Radiografia/tendências , Reprodutibilidade dos Testes , Estudos Retrospectivos , Caixa Torácica/anatomia & histologia , Caixa Torácica/diagnóstico por imagem , Caixa Torácica/crescimento & desenvolvimento , Escoliose/fisiopatologia , Curvaturas da Coluna Vertebral/diagnóstico por imagem , Tronco/anatomia & histologia , Tronco/diagnóstico por imagem
4.
Med Phys ; 46(12): 5454-5466, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31529513

RESUMO

PURPOSE: This paper studies spatial resolution that is achievable with a fast slot-scanning tomosynthesis approach for orthopedic examinations. Hereby, we use parallel scanning motion implemented in a twin robotic x-ray system. METHODS: We have measured and analyzed the modulation transfer function (MTF) for various combinations of scanning speed, x-ray tube voltage, pulse length, the nominal focal spot size as well as source-to-object distances. Moreover, we present a theoretical model which describes the system in terms of the MTF. The system was equipped with newly developed linear trajectory prototypes for slot scanning. The acquired images form the basis for a small-angle tomosynthesis reconstruction. In total, three different scanning speeds (27, 14, 8 cm/s), pulse lengths (1, 2, 4 ms), tube voltages (80, 100, 120 kV), two nominal focal spot sizes (0.6, 1.0), and three source-to-object distances (950, 1050, 1150 mm) were investigated. To determine the resolution capabilities, we measured the MTF for the given parameter space. The results were then used to design a filter that yields a desired resolution in the reconstructed image. In addition, we also measured the noise power spectrum (NPS) to show the influence of the aforementioned filters on the noise distribution. RESULTS: We have shown that the presented model is in good agreement with the performed measurements. Scanning speed and pulse width have an impact on the MTF in the scanning direction. Up to a travel distance of 0.3 mm during an x-ray pulse, an isotropic resolution can be achieved. Longer pulse width or higher scanning speed cause anisotropic resolution. Moreover, it is shown that none of the investigated parameters have an influence on the MTF perpendicular to the scanning direction (slot direction). The 10% MTF value ranges between 9 and 18 lp/cm in the scanning direction and about 18 lp/cm in slot direction. Tube voltage, nominal focal spot size as well as the source-to-object distance showed no major impact on the system MTF. In terms of the anisotropic resolution capabilities, we have shown that limiting the resolution in the slot direction to obtain isotropic resolution is possible yet at the cost of an inhomogeneous noise pattern. However, maintaining the resolution in slot direction will provide a better edge response and a more homogeneous noise texture at the cost of an inhomogeneous image resolution. CONCLUSIONS: We have demonstrated the feasibility of the slot-scanning technique using a twin-robotic x-ray system. Even the fastest scanning mode (27 cm/s) yields image resolution on a level that is sufficient for typical orthopedic examinations in terms of musculoskeletal (MSK) measurements. Moreover, it could be shown that the application of specifically designed target MTFs on two-dimensional x-ray images is feasible.


Assuntos
Intensificação de Imagem Radiográfica/métodos , Humanos , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Razão Sinal-Ruído , Tronco/diagnóstico por imagem
5.
Obesity (Silver Spring) ; 27(10): 1652-1660, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31436387

RESUMO

OBJECTIVE: This study examined trajectories of trunk fat mass (FM) accrual during emerging adulthood of individuals categorized, at 36 years of age, as having higher compared with lower scores of (1) metabolic risk and (2) blood pressure risk. METHODS: Fifty-five individuals from the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-2017) were assessed from adolescence (mean [SD], 11.5 [1.8] years) through emerging adulthood (26.2 [2.2] years) and into early adulthood (35.6 [2.2] years) (median 11 visits per individual). Sex-specific median splits of continuous standardized risk scores at 36 years of age were created. Dual-energy x-ray absorptiometry-assessed trunk FM trajectories were analyzed using multilevel random effects models. RESULTS: Higher risk scores of blood pressure risk and metabolic risk had significantly steeper trajectories of fat development (0.45 [0.11] and 0.44 [0.11] log g, respectively) than the lower risk scores. Dietary fat was not related (P > 0.05). Physical activity was negatively related (-0.04 [0.02] physical activity score) to trunk FM development during emerging adulthood. CONCLUSIONS: Young adults with higher metabolic risk at 36 years of age had greater trunk FM development during both adolescence and emerging adulthood, supporting the need for intervention at both these critical periods of fat accrual.


Assuntos
Tecido Adiposo/crescimento & desenvolvimento , Envelhecimento/fisiologia , Trajetória do Peso do Corpo , Doenças Cardiovasculares/etiologia , Doenças Metabólicas/etiologia , Tronco/crescimento & desenvolvimento , Absorciometria de Fóton , Tecido Adiposo/diagnóstico por imagem , Tecido Adiposo/metabolismo , Adiposidade/fisiologia , Adolescente , Adulto , Fatores Etários , Pressão Sanguínea/fisiologia , Distribuição da Gordura Corporal , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/metabolismo , Criança , Exercício Físico/fisiologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Doenças Metabólicas/diagnóstico , Doenças Metabólicas/patologia , Fatores de Risco , Tronco/diagnóstico por imagem , Adulto Jovem
6.
Gait Posture ; 73: 39-44, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31299502

RESUMO

BACKGROUND: Surface-topography has been used for almost two decades in the radiation-free clinical evaluation of spinal posture. So far, it was limited to the analysis of back surface and spine. In order to better understand, diagnose and treat complex spinal pathologies, it is important to measure the whole torso. RESEARCH QUESTION: Purpose of this study was to introduce and test an application that allows 360° reconstruction and analysis of the patient's torso. METHODS: The application uses the information gathered from eight distinct scans and angles. For validation we used an Alderson phantom as an anthropomorphic body. Defined areas and volumes were measured by CT and surface-topography. Inter- and intra-rater reliability was tested in 35 healthy subjects by two observers. RESULTS: The results revealed good correspondence between systems in the imaging and evaluation of the Alderson model (5.3-0.5%). Inter- (0.9-0.98) and intra-rater reliability (0.8-0.95) testing revealed good and excellent results in the detection of almost all body surface structures and measurement of areas and volumes. Only area and volume measurements using jugular notch as a reference showed partly moderate results in reliability (0.62-0.93) testing. SIGNIFICANCE: We were able to introduce a novel 360° torso scan application using surface topography to reconstruct torso measurements. The results of our study showed its high validity and reliability. In the future, this application needs to be tested in patients with spinal pathologies. In summary, this new application may help to better understand, diagnose and treat patients with pathologies of torso and spine.


Assuntos
Imageamento Tridimensional/métodos , Coluna Vertebral/diagnóstico por imagem , Tronco/diagnóstico por imagem , Feminino , Voluntários Saudáveis , Humanos , Masculino , Modelos Anatômicos , Reprodutibilidade dos Testes , Tomografia Computadorizada por Raios X
7.
Top Magn Reson Imaging ; 28(3): 101-124, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31188271

RESUMO

The potential value of ultrahigh field (UHF) magnetic resonance imaging (MRI) and spectroscopy to biomedical research and in clinical applications drives the development of technologies to overcome its many challenges. The increased difficulties of imaging the human torso compared with the head include its overall size, the dimensions and location of its anatomic targets, the increased prevalence and magnitude of physiologic effects, the limited availability of tailored RF coils, and the necessary transmit chain hardware. Tackling these issues involves addressing notoriously inhomogeneous transmit B1 (B1) fields, limitations in peak B1, larger spatial variations of the static magnetic field B0, and patient safety issues related to implants and local RF power deposition. However, as research institutions and vendors continue to innovate, the potential gains are beginning to be realized. Solutions overcoming the unique challenges associated with imaging the human torso are reviewed as are current studies capitalizing on the benefits of UHF in several anatomies and applications. As the field progresses, strategies associated with the RF system architecture, calibration methods, RF pulse optimization, and power monitoring need to be further integrated into the MRI systems making what are currently complex processes more streamlined. Meanwhile, the UHF MRI community must seize the opportunity to build upon what have been so far proof of principle and feasibility studies and begin to further explore the true impact in both research and the clinic.


Assuntos
Imagem por Ressonância Magnética/métodos , Tronco/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética/efeitos adversos , Imagem por Ressonância Magnética/instrumentação , Imagem por Ressonância Magnética/tendências , Ondas de Rádio
8.
Med Phys ; 46(6): 2621-2628, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30924935

RESUMO

PURPOSE: Respiratory gated four-dimensional (4D) single photon emission computed tomography (SPECT) with phase-matched CT reduces respiratory blurring and attenuation correction (AC) artifacts in cardiac SPECT. This study aims to develop and investigate the effectiveness of an interpolated CT (ICT) method for improved cardiac SPECT AC using simulations. METHODS: We used the 4D XCAT phantom to simulate a population of ten patients varied in gender, anatomy, 99m Tc-sestamibi distribution, respiratory patterns, and disease states. Simulated 120 SPECT projection data were rebinned into six equal count gates. Activity and attenuation maps in each gate were averaged as gated SPECT and CT (GCT). Three helical CTs were simulated at end-inspiration (HCT-IN), end-expiration (HCT-EX), and mid-respiration (HCT-MID). The ICTs were obtained from HCT-EX and HCT-IN using the motion vector field generated between them from affine plus b-spline registration. Projections were reconstructed by OS-EM method, using GCT, ICT, and three HCTs for AC. Reconstructed images of each gate were registered to end-expiration and averaged to generate the polar plots. Relative difference for each segment and relative defect size were computed using images of GCT AC as reference. RESULTS: The average of maximum relative difference through ten phantoms was 7.93 ± 4.71%, 2.50 ± 0.98%, 3.58 ± 0.74%, and 2.14 ± 0.56% for noisy HCT-IN, HCT-MID, HCT-EX, and ICT AC data, respectively. The ICT showed closest defect size to GCT while the differences from HCTs can be over 40%. CONCLUSION: We conclude that the performance of ICT is similar to GCT. It improves the image quality and quantitative accuracy for respiratory-gated cardiac SPECT as compared to conventional HCT, while it can potentially further reduce the radiation dose of GCT.


Assuntos
Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Técnicas de Imagem de Sincronização Respiratória/instrumentação , Tomografia Computadorizada de Emissão de Fóton Único/instrumentação , Humanos , Doses de Radiação , Tronco/diagnóstico por imagem
9.
IEEE Comput Graph Appl ; 39(1): 26-43, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30869596

RESUMO

The visualization toolkit (VTK) is a popular cross-platform, open source toolkit for scientific and medical data visualization, processing, and analysis. It supports a wide variety of data formats, algorithms, and rendering techniques for both polygonal and volumetric data. In particular, VTK's volume rendering module has long provided a comprehensive set of features such as plane clipping, color and opacity transfer functions, lighting, and other controls needed for visualization. However, due to VTK's legacy OpenGL backend and its reliance on a deprecated API, the system did not take advantage of the latest improvements in graphics hardware or the flexibility of a programmable pipeline. Additionally, this dependence on an antiquated pipeline posed restrictions when running on emerging computing platforms, thereby limiting its overall applicability. In response to these shortcomings, the VTK community developed a new and improved volume rendering module, which not only provides a modern graphics processing unit-based implementation, but also augments its capabilities with new features such as fast volume clipping, gradient-magnitude-based opacity modulation, render to texture, and hardware-based volume picking.


Assuntos
Diagnóstico por Imagem , Interpretação de Imagem Assistida por Computador , Processamento de Imagem Assistida por Computador , Software , Algoritmos , Gráficos por Computador , Humanos , Dente/diagnóstico por imagem , Tronco/diagnóstico por imagem
10.
Eur J Radiol ; 111: 81-87, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30691670

RESUMO

OBJECTIVES: This study aims to evaluate the radiation exposure to patients undergoing an abdominopelvic or a chest and abdominopelvic (trunk) CT examination and to assess compliance to imaging referral guidelines. METHODS: To this end, 357 standard abdominopelvic and trunk CT scans were collected from 8 Belgian institutions in 2011 and 2015. Effective dose (E) and collective dose were calculated using CT dose descriptors (CTDIvol and DLP), which were obtained from dose reports generated by the CT scanner. Subsequently, these CT requests were compared against the national referral guidelines to assess compliance. Population estimates for dose and compliance were obtained using multilevel linear regression and generalized estimating equation models. RESULTS: Between 2011 and 2015, a significant decrease of 28% in CTDIvol and DLP was found for abdominopelvic CT. The corresponding E decreased by 27%, and the collective dose by 23%. For trunk CT, a non-significant decrease of 6% was found in CTDIvol and a significant decrease of 14% in both DLP and E. However, the collective dose of trunk examinations increased by 39%. In 2011, 24% of the abdominopelvic examinations were not compliant with the guidelines, whereas this percentage dropped to 17% in 2015. Non-justified examinations accounted for 8% and 12% of all trunk CT scans in 2011 and 2015, respectively. CONCLUSION: Between 2011 and 2015, there was a decrease in dose for patients undergoing abdominopelvic or trunk CT in Belgium. However, a fraction of the estimated doses are linked to unnecessary CT examinations, which should be avoided.


Assuntos
Abdome/efeitos da radiação , Fidelidade a Diretrizes , Pelve/efeitos da radiação , Tomografia Computadorizada por Raios X , Tronco/efeitos da radiação , Abdome/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Bélgica , Feminino , Guias como Assunto , Humanos , Masculino , Pessoa de Meia-Idade , Pelve/diagnóstico por imagem , Doses de Radiação , Exposição à Radiação , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Tronco/diagnóstico por imagem , Adulto Jovem
11.
J Biomech ; 84: 161-171, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30638978

RESUMO

Recent advances in medical imaging techniques have allowed pure displacement-control trunk models to estimate spinal loads with no need to calculate muscle forces. Sensitivity of these models to the errors in post-imaging evaluation of displacements (reported to be ∼0.4-0.9° and 0.2-0.3 mm in vertebral displacements) has not yet been investigated. A Monte Carlo analysis was therefore used to assess the sensitivity of results in both musculoskeletal (MS) and passive finite element (FE) spine models to errors in measured displacements. Six static activities in upright standing, flexed, and extended postures were initially simulated using a force-control hybrid MS-FE model. Computed vertebral displacements were subsequently used to drive two distinct fully displacement-control MS and FE models. Effects of alterations in the reference vertebral displacements (at 3 error levels with SD (standard deviation) = 0.1, 0.2, and 0.3 mm in input translations together with, respectively, 0.2, 0.4, and 0.6° in input rotations) were investigated on the model predictions. Results indicated that outputs of both models had substantial task-dependent sensitivities to errors in the measured vertebral translations. For instance, L5-S1 intradiscal pressures (IDPs) were considerably affected (SD values reaching 1.05 MPa) and axial compression and shear forces even reversed directions as translation errors increased to 0.3 mm. Outputs were however generally much less sensitive to errors in measured vertebral rotations. Accounting for the accuracies in image-based kinematics measurements, therefore, it is concluded that the current measured vertebral translation errors at and beyond 0.1 mm are too large to drive biomechanical models of the spine.


Assuntos
Análise de Elementos Finitos , Fenômenos Mecânicos , Imagem Molecular , Tronco/diagnóstico por imagem , Tronco/fisiologia , Idoso , Fenômenos Biomecânicos , Humanos , Masculino , Método de Monte Carlo , Músculo Esquelético/fisiologia , Postura , Pressão , Amplitude de Movimento Articular , Coluna Vertebral/fisiologia , Suporte de Carga
12.
Med Phys ; 46(3): 1272-1285, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30614020

RESUMO

PURPOSE: Quantification of body composition plays an important role in many clinical and research applications. Radiologic imaging techniques such as Dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and computed tomography (CT) imaging make accurate quantification of the body composition possible. However, most current imaging-based methods need human interaction to quantify multiple tissues. When dealing with whole-body images of many subjects, interactive methods become impractical. This paper presents an automated, efficient, accurate, and practical body composition quantification method for low-dose CT images. METHOD: Our method, named automatic anatomy recognition body composition analysis (AAR-BCA), aims to quantify four tissue components in body torso (BT) - subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), bone tissue, and muscle tissue - from CT images of given whole-body positron emission tomography/computed tomography (PET/CT) acquisitions. AAR-BCA consists of three key steps - modeling BT with its ensemble of key objects from a population of patient images, recognition or localization of these objects in a given patient image I, and delineation and quantification of the four tissue components in I guided by the recognized objects. In the first step, from a given set of patient images and the associated delineated objects, a fuzzy anatomy model of the key object ensemble, including anatomic organs, tissue regions, and tissue interfaces, is built where the objects are organized in a hierarchical order. The second step involves recognizing, or finding roughly the location of, each object in any given whole-body image I of a patient following the object hierarchy and guided by the built model. The third step makes use of this fuzzy localization information of the objects and the intensity distributions of the four tissue components, already learned and encoded in the model, to optimally delineate in a fuzzy manner and quantify these components. All parameters in our method are determined from training datasets. RESULTS: Thirty-eight low-dose CT images from different subjects are tested in a fivefold cross-validation strategy for evaluating AAR-BCA with a 23-15 train-test dataset division. For BT, over all objects, AAR-BCA achieves a false-positive volume fraction (FPVF) of 3.7% and false-negative volume fraction (FNVF) of 3.8%. Notably, SAT achieves both a FPVF and FNVF under 3%. For bone tissue, it achieves a FPVF and a FNVF both under 3.5%. For VAT tissue, the FNVF of 4.8% is higher than for other objects and so also for muscle (4.7%). The level of accuracy for the four tissue components in individual body subregions mostly remains at the same level as for BT. The processing time required per patient image is under a minute. CONCLUSIONS: Motivated by applications in cancer and systemic diseases, our goal in this paper was to seek a practical method for body composition quantification which is automated, accurate, and efficient, and works on BT in low-dose CT. The proposed AAR-BCA method toward this goal can quantify four tissue components including SAT, VAT, bone tissue, and muscle tissue in the body torso with under 5% overall error. All needed parameters can be automatically estimated from the training datasets.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Modelos Anatômicos , Neoplasias/diagnóstico por imagem , Neoplasias/patologia , Tomografia Computadorizada por Raios X/métodos , Tronco/patologia , Imagem Corporal Total/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Composição Corporal , Feminino , Lógica Fuzzy , Humanos , Masculino , Pessoa de Meia-Idade , Reconhecimento Automatizado de Padrão , Estudos Retrospectivos , Tronco/diagnóstico por imagem
13.
Med Eng Phys ; 63: 63-71, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30467027

RESUMO

Externally visible deformities are cosmetic features of great concern for Adolescent Idiopathic Scoliosis (AIS) patients. Current assessment techniques for AIS do not fully encompass the external deformity. A non-invasive method capable of capturing superficial anatomy, such as 3D scanning, would enable better qualitative and quantitative evaluation of cosmesis. This study aimed to quantify the accuracy of commonly available scanners, in assessing posterior asymmetry in AIS. The technique of 3D surface deviation analysis was proposed as a suitable method for comparing the models created by each scanner. Eight plaster cast moulds manufactured to create braces for AIS patients were used as test samples. Four 3D scanners were selected: Solutionix RexScan CS+; Artec Eva; Microsoft Kinect V1; iPhone with 123D Catch App. These scanners were selected from those available as representative of a range of scanning technologies. Each cast was scanned and 3D models created. A simulated rib hump measurement was obtained and the surface-to-surface deviations between the Solutionix scan and all other scans were determined. The Solutionix scanner is a metrology scanner of very high quality and so it was selected as the reference. Surface-to-surface deviations were calculated in the positive and negative directions separately to specifically identify size and volume inaccuracies created by the scans. Surface deviations showed excellent agreement between the Solutionix and the Eva with deviations of +0.17 ±â€¯0.17 mm (Eva regions larger) and -0.20 ±â€¯0.32 mm (Eva regions smaller) (mean±SD). The Kinect showed lower agreement (+1.58 ±â€¯1.50 mm and -0.58 ±â€¯0.58 mm). The iPhone scans were not able to be scaled to the correct size, so were excluded. Rib hump measurements with all scanners were within clinical measurement variability (±4.9 deg) of the known values. These commercially available 3D scanners are capable of imaging torso shape in 3D and deriving clinically relevant external deformity measures. The non-invasive 3D topographic information provided can be used to improve assessment of torso shape in spinal deformity patients.


Assuntos
Imageamento Tridimensional , Escoliose/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Tronco/diagnóstico por imagem , Calibragem , Humanos , Imagem por Ressonância Magnética , Propriedades de Superfície , Tomografia Computadorizada por Raios X
14.
Magn Reson Med ; 81(3): 2090-2105, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30230021

RESUMO

PURPOSE: Simulating the interaction of the human body with electromagnetic fields is an active field of research. Individualized models are increasingly being used, as anatomical differences affect the simulation results. We introduce a processing pipeline for creating individual surface-based models of the human head and torso for application in simulation software based on unstructured grids. The pipeline is designed for easy applicability and is publicly released on figshare. METHODS: The pipeline covers image acquisition, segmentation, generation of segmentation masks, and surface mesh generation of the single, external boundary of each structure of interest. Two gradient-echo sequences are used for image acquisition. Structures of the head and body are segmented using several atlas-based approaches. They consist of bone/skull, subarachnoid cerebrospinal fluid, gray matter, white matter, spinal cord, lungs, the sinuses of the skull, and a combined class of all other structures including skin. After minor manual preparation, segmentation images are processed to segmentation masks, which are binarized images per segmented structure free of misclassified voxels and without an internal boundary. The proposed workflow is applied to 2 healthy subjects. RESULTS: Individual differences of the subjects are well represented. The models are proven to be suitable for simulation of the RF electromagnetic field distribution. CONCLUSION: Image segmentation, creation of segmentation masks, and surface mesh generation are highly automated. Manual interventions remain for preparing the segmentation images prior to segmentation mask generation. The generated surfaces exhibit a single boundary per structure and are suitable inputs for simulation software.


Assuntos
Encéfalo/diagnóstico por imagem , Cabeça/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética , Tronco/diagnóstico por imagem , Adulto , Algoritmos , Líquido Cefalorraquidiano/diagnóstico por imagem , Simulação por Computador , Campos Eletromagnéticos , Substância Cinzenta/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Masculino , Reconhecimento Automatizado de Padrão , Imagens de Fantasmas , Linguagens de Programação , Pele/diagnóstico por imagem , Crânio/diagnóstico por imagem , Software , Medula Espinal/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto Jovem
15.
Spine Deform ; 7(1): 125-131, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30587305

RESUMO

OBJECTIVE: We investigated the relationship between cross-sectional area (CSA) of paravertebral muscle and trunk tilt at standing and walking in adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: Although the importance of back muscles for the development of spinal kyphosis was well described, the influence on maintaining the sagittal balance was unclear. METHODS: Forty-five female patients (mean age, 68.8 years) with ASD were studied. We measured sagittal vertical axis [SVA], pelvic tilt [PT], and pelvic incidence-lumbar lordosis [PI-LL]) by lateral spine radiograph. For the assessment of trunk tilt standing-trunk tilt angle (STA) by lateral standing radiograph, gait-trunk tilt angle (GTA) by lateral gait images, and the increasing trunk tilt angle (ITA) by subtracting the STA from the GTA were calculated. Using L1/2 and L4/5 axial MRI, the CSAs of bilateral multifidus muscles (MF) and elector spinae (ES) removed fat by Image J software were calculated. We examined the correlation between trunk tilt angle (STA, GTA, and ITA) and spinopelvic parameters (SVA, PT, and PI minus LL) and also the correlation among muscle CSA, trunk tilt angle (STA, GTA, and ITA), and Oswestry Disability Index (ODI). RESULTS: The mean STA, GTA, and ITA were 4.2°, 13.0°, and 8.8°, respectively. The CSAs of back muscles were 278 mm2 at L1/2 MF, 1,687 mm2 at L1/2 ES, 636 mm2 at L4/5 MF, and 1,355 mm2 at L4/5 ES, respectively. Trunk tilt angle had significant relations with spinopelvic parameters. Concerning about muscle CSA, significant correlations were observed between STA and L4/5 MF (r = -0.517), GTA and L1/2 ES (r = -0.461) and L4/5 MF (r = -0.476), and ITA and L1/2 ES(r = -0.429). ODI showed significant correlation with STA and GTA. CONCLUSIONS: Paravertebral muscles were crucial to keep upright posture during walking as well as standing.


Assuntos
Músculos Paraespinais/fisiopatologia , Curvaturas da Coluna Vertebral/fisiopatologia , Posição Ortostática , Idoso , Feminino , Humanos , Cifose/diagnóstico por imagem , Cifose/fisiopatologia , Músculos Paraespinais/diagnóstico por imagem , Ossos Pélvicos/diagnóstico por imagem , Radiografia/métodos , Curvaturas da Coluna Vertebral/diagnóstico por imagem , Tronco/diagnóstico por imagem , Tronco/fisiopatologia , Caminhada/fisiologia
16.
Magn Reson Med ; 81(3): 1833-1848, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30338864

RESUMO

PURPOSE: Quantitative susceptibility mapping (QSM) has found increasing clinical applications. However, to reduce scan time, clinical acquisitions often use reduced resolution and coverage, particularly in the through-slice dimension. The effect of these factors on QSM has begun to be assessed using only balloon phantoms and downsampled brain images. Here, we investigate the effects (and their sources) of low resolution or coverage on QSM using both simulated and acquired images. METHODS: Brain images were acquired at 1 mm isotropic resolution and full brain coverage, and low resolution (up to 6 mm slice thickness) or coverage (down to 20 mm) in 5 healthy volunteers. Images at reduced resolution or coverage were also simulated in these volunteers and in a new, anthropomorphic, numerical phantom. Mean susceptibilities in 5 brain regions, including white matter, were investigated over varying resolution and coverage. RESULTS: The susceptibility map contrast decreased with increasing slice thickness and spacing, and with decreasing coverage below ~40 mm for 2 different QSM pipelines. Our simulations showed that calculated susceptibility values were erroneous at low resolution or very low coverage, because of insufficient sampling and overattenuation of the susceptibility-induced field perturbations. Susceptibility maps calculated from simulated and acquired images showed similar behavior. CONCLUSIONS: Both low resolution and low coverage lead to loss of contrast and errors in susceptibility maps. The widespread clinical practice of using low resolution and coverage does not provide accurate susceptibility maps. Simulations in images of healthy volunteers and in a new, anthropomorphic numerical phantom were able to accurately model low-resolution and low-coverage acquisitions.


Assuntos
Encéfalo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Substância Branca/diagnóstico por imagem , Adulto , Algoritmos , Antropometria , Mapeamento Encefálico/métodos , Simulação por Computador , Feminino , Cabeça/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Imagem por Ressonância Magnética , Masculino , Modelos Teóricos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Tronco/diagnóstico por imagem
17.
J Ultrasound Med ; 38(1): 15-26, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29688574

RESUMO

Rehabilitative ultrasound (US) imaging is one of the popular methods for investigating muscle morphologic characteristics and dimensions in recent years. The reliability of this method has been investigated in different studies. As studies have been performed with different designs and quality, reported values of rehabilitative US have a wide range. The objective of this study was to systematically review the literature conducted on the reliability of rehabilitative US imaging for the assessment of deep abdominal and lumbar trunk muscle dimensions. The PubMed/MEDLINE, Scopus, Google Scholar, Science Direct, Embase, Physiotherapy Evidence, Ovid, and CINAHL databases were searched to identify original research articles conducted on the reliability of rehabilitative US imaging published from June 2007 to August 2017. The articles were qualitatively assessed; reliability data were extracted; and the methodological quality was evaluated by 2 independent reviewers. Of the 26 included studies, 16 were considered of high methodological quality. Except for 2 studies, all high-quality studies reported intraclass correlation coefficients (ICCs) for intra-rater reliability of 0.70 or greater. Also, ICCs reported for inter-rater reliability in high-quality studies were generally greater than 0.70. Among low-quality studies, reported ICCs ranged from 0.26 to 0.99 and 0.68 to 0.97 for intra- and inter-rater reliability, respectively. Also, the reported standard error of measurement and minimal detectable change for rehabilitative US were generally in an acceptable range. Generally, the results of the reviewed studies indicate that rehabilitative US imaging has good levels of both inter- and intra-rater reliability.


Assuntos
Músculos Abdominais/diagnóstico por imagem , Músculos do Dorso/diagnóstico por imagem , Ultrassonografia/métodos , Músculos Abdominais/fisiopatologia , Músculos do Dorso/fisiopatologia , Humanos , Região Lombossacral/diagnóstico por imagem , Reprodutibilidade dos Testes , Tronco/diagnóstico por imagem
18.
Gastroenterology ; 156(4): 966-975.e10, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30445012

RESUMO

BACKGROUND & AIMS: We compared fat storage in the abdominal region among individuals from 5 different ethnic-racial groups to determine whether fat storage is associated with disparities observed in metabolic syndrome and other obesity-associated diseases. METHODS: We collected data from 1794 participants in the Multiethnic Cohort Study (60-77 years old; of African, European [white], Japanese, Latino, or Native Hawaiian ancestry) with body mass index values of 17.1-46.2 kg/m2. From May 2013 through April 2016, participants visited the study clinic to undergo body measurements, an interview, and a blood collection. Participants were evaluated by dual-energy x-ray absorptiometry and abdominal magnetic resonance imaging. Among ethnic groups, we compared adiposity of the trunk, intra-abdominal visceral cavity, and liver, adjusting for total fat mass; we evaluated the association of adult weight change with abdominal adiposity; and we examined the prevalence of metabolic syndrome mediated by abdominal adiposity. RESULTS: Relative amounts of trunk, visceral, and liver fat varied significantly with ethnicity-they were highest in Japanese Americans, lowest in African Americans, and intermediate in the other groups. Compared with African Americans, the mean visceral fat area was 45% and 73% greater in Japanese American men and women, respectively, and the mean measurements of liver fat were 61% and 122% greater in Japanese American men and women. The visceral and hepatic adiposity associated with weight gain since participants were 21 years old varied in a similar pattern among ethnic-racial groups. In the mediation analysis, visceral and liver fat jointly accounted for a statistically significant fraction of the difference in metabolic syndrome prevalence, compared with white persons, for African Americans, Japanese Americans, and Native Hawaiian women, independently of total fat mass. CONCLUSIONS: In an analysis of data from the participants in the Multiethnic Cohort Study, we found extensive differences among ethnic-racial groups in the propensity to store fat intra-abdominally. This observation should be considered by clinicians in the prevention and early detection of metabolic disorders.


Assuntos
Adiposidade , Grupos Étnicos/estatística & dados numéricos , Gordura Intra-Abdominal , Síndrome Metabólica/etnologia , Absorciometria de Fóton , Afro-Americanos/estatística & dados numéricos , Idoso , Americanos Asiáticos/estatística & dados numéricos , Composição Corporal , Grupo com Ancestrais do Continente Europeu/estatística & dados numéricos , Feminino , Hawaii/etnologia , Hispano-Americanos/estatística & dados numéricos , Humanos , Gordura Intra-Abdominal/diagnóstico por imagem , Japão/etnologia , Fígado/diagnóstico por imagem , Imagem por Ressonância Magnética , Masculino , Grupo com Ancestrais Oceânicos/estatística & dados numéricos , Prevalência , Tronco/diagnóstico por imagem , Estados Unidos/epidemiologia , Ganho de Peso
19.
Int J Comput Assist Radiol Surg ; 14(3): 473-482, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30390179

RESUMO

PURPOSE: Automated segmentation of torso organs from positron emission tomography/computed tomography (PET/CT) images is a prerequisite step for nuclear medicine image analysis. However, accurate organ segmentation from clinical PET/CT is challenging due to the poor soft tissue contrast in the low-dose CT image and the low spatial resolution of the PET image. To overcome these challenges, we developed a multi-atlas segmentation (MAS) framework for torso organ segmentation from 2-deoxy-2-[18F]fluoro-D-glucose PET/CT images. METHOD: Our key idea is to use PET information to compensate for the imperfect CT contrast and use surface-based atlas fusion to overcome the low PET resolution. First, all the organs are segmented from CT using a conventional MAS method, and then the abdomen region of the PET image is automatically cropped. Focusing on the cropped PET image, a refined MAS segmentation of the abdominal organs is performed, using a surface-based atlas fusion approach to reach subvoxel accuracy. RESULTS: This method was validated based on 69 PET/CT images. The Dice coefficients of the target organs were between 0.80 and 0.96, and the average surface distances were between 1.58 and 2.44 mm. Compared to the CT-based segmentation, the PET-based segmentation gained a Dice increase of 0.06 and an ASD decrease of 0.38 mm. The surface-based atlas fusion leads to significant accuracy improvement for the liver and kidneys and saved ~ 10 min computation time compared to volumetric atlas fusion. CONCLUSIONS: The presented method achieves better segmentation accuracy than conventional MAS method within acceptable computation time for clinical applications.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Fígado/diagnóstico por imagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Tronco/diagnóstico por imagem , Índice de Massa Corporal , Aprendizado Profundo , Feminino , Fluordesoxiglucose F18 , Humanos , Rim/diagnóstico por imagem , Masculino
20.
J Pak Med Assoc ; 69(7): 1059, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31983750

RESUMO

Hodgkin lymphoma is a high grade lymphoma which is usually confined to the lymphnodes. Extranodal involvement of the Hodgkin lymphoma is uncommon but any organ can be involved.. Extramedullary haematopoiesis is the production of red cells outside the medullary cavity in response to failure of erythrogenesis in bone marrow which can occur due to many diseases with thalassaemia and myelofibrosis being most common. We present a case of a 21 year old patient who underwent PET-CT scan for the staging of Hodgkin lymphoma and revealed co-existing extramedullary haematopoiesis secondary to known thalassaemia.


Assuntos
Hematopoese Extramedular/fisiologia , Doença de Hodgkin , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Talassemia beta , Adulto , Doença de Hodgkin/diagnóstico por imagem , Doença de Hodgkin/fisiopatologia , Humanos , Masculino , Tronco/diagnóstico por imagem , Adulto Jovem , Talassemia beta/diagnóstico por imagem , Talassemia beta/fisiopatologia
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