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1.
J Comput Assist Tomogr ; 44(5): 772-779, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32936579

RESUMO

OBJECTIVE: To create a map of iodine densities within affected segments of small-bowel Crohn disease (CD) derived from contrast-enhanced dual-energy computed tomography enterography (DECTE) studies. METHODS: Twenty CD patients imaged with intravenous contrast-enhanced DECTE between June 2016 and December 2017 were retrospectively identified. Ten patients without clinical evidence of CD and 8 normal-appearing jejunal segments in CD patients were controls. Using prototype software, 8 manual contours were drawn along the mucosa of affected segments. Relatively normal-appearing bowel was included at the edges. These contours served as a basis for iodine density calculation and 3-dimensional iodine density map rendering. Color-coded iodine densities allowed detection and quantification of the most and least dense portion of each segment and also permitted relative comparison between segments. RESULTS: The average iodine density per CD involved segment ranged 1.0 to 3.3 mg/mL, which differed significantly from normal ileum (P < 0.0001) and normal-appearing jejunum in patients with CD (P = 0.0009). Standard deviations ranged from 0.8 to 1.7 mg/mL, which differed significantly from normal ileum (P = 0.0039) and normal-appearing jejunum in patients with CD (P = 0.0056). The amplitude of the power spectrum ranged from 0.66 to 3.3 demonstrating patches of iodine rather than uniform distribution. This differed significantly from normal ileum (P = 0.0005) and normal-appearing jejunum in patients with CD (P = 0.0004). CONCLUSIONS: Heterogeneous CD activity and distribution can be displayed as iodine density maps created from DECTE.


Assuntos
Meios de Contraste/farmacocinética , Doença de Crohn/diagnóstico por imagem , Imageamento Tridimensional/métodos , Iodo/farmacocinética , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Feminino , Trato Gastrointestinal/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
2.
PLoS One ; 15(9): e0231431, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881876

RESUMO

OBJECTIVE: To compare the radiation dose and the objective and subjective image quality of 80 kVp and 80/150 kVp with tin filter (80/Sn150 kVp) computed tomography (CT) in oncology patients. METHODS: One-hundred-and-forty-five consecutive oncology patients who underwent third-generation dual-source dual-energy CT of the abdomen for evaluation of malignant visceral, peritoneal, extraperitoneal, and bone tumor were retrospectively recruited. Two radiologists independently reviewed each observation in 80 kVp CT and 80/Sn150 kVp CT. Modified line-density profile of the tumor and contrast-to-noise ratio (CNR) were measured. Diagnostic confidence, lesion conspicuity, and subjective image quality were calculated and compared between image sets. The effective dose and size-specific dose estimate (SSDE) were calculated in the image sets. RESULTS: Modified line-density profile analysis revealed higher attenuation differences between the tumor and normal tissue in 80 kVp CT than in 80/Sn150 kVp CT (127 vs. 107, P = 0.05). The 80 kVp CT showed increased CNR in the liver (8.0 vs. 7.6) and the aorta (18.9 vs. 16.3) than the 80/Sn150 kVp CT. The 80 kVp CT yielded higher enhancement of organs (4.9 ± 0.2 vs. 4.7 ± 0.4, P<0.001) and lesion conspicuity (4.9 ± 0.3 vs. 4.8 ± 0.5, P = 0.035) than the 80/Sn150 kVp CT; overall image quality and confidence index were comparable. The effective dose was reduced by 45.2% with 80 kVp CT (2.3 mSv ± 0.9) compared to 80/Sn150 kVp CT (4.1 mSv ± 1.5). The SSDE was 7.4 ± 3.8 mGy on 80/Sn150 kVp CT and 4.1 ± 2.2 mGy on 80 kVp CT. CONCLUSIONS: The 80 kVp CT reduced the radiation dose by 45.2% in oncology patients while showing comparable or superior image quality to that of 80/Sn150 kVp CT for abdominal tumor evaluation.


Assuntos
Neoplasias/diagnóstico por imagem , Doses de Radiação , Intensificação de Imagem Radiográfica/instrumentação , Estanho , Tomografia Computadorizada por Raios X/instrumentação , Abdome/diagnóstico por imagem , Idoso , Algoritmos , Meios de Contraste/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pelve/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos
3.
Br J Radiol ; 93(1114): 20200565, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783630

RESUMO

OBJECTIVES: To investigate via computer simulation, an optimised tube voltage (kVp) range for caesium iodide (CsI)-based digital radiography (DR) of the abdomen, pelvis and lumbar spine. METHODS: Software capable of simulating abdomen, pelvis and spine radiographs was used. Five evaluators graded clinical image criteria in images of 20 patients at tube voltages ranging from 60 to 120 kVp in 10 kVp increments. These criteria were scored blindly against the same patient reconstructed at a specific reference kVp. Linear mixed effects analysis was used to evaluate image scores for each criterion and test for statistical significance. RESULTS: Score was dependent on tube voltage and image criteria; both were statistically significant. All criteria for all anatomies scored very poorly at 60 kVp. Scores for abdomen, pelvis and spine imaging peaked at 70, 70 and 100 kVp, respectively, but other kVp values were not significantly poorer. CONCLUSIONS: Results indicate optimum tube voltages of 70 kVp for abdomen and pelvis (with an optimum range 70-120 kVp), and 100 kVp (optimum range 80-120 kVp) for lumbar spine. ADVANCES IN KNOWLEDGE: There are no recommendations for optimised tube voltage parameters for DR abdomen, pelvis or lumbar spine imaging. This study has investigated and recommended an optimal tube voltage range.


Assuntos
Abdome/diagnóstico por imagem , Pelve/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Coluna Vertebral/diagnóstico por imagem , Algoritmos , Césio , Simulação por Computador , Humanos , Iodetos , Imagens de Fantasmas , Interpretação de Imagem Radiográfica Assistida por Computador , Software
4.
Biosens Bioelectron ; 165: 112361, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32729494

RESUMO

The recent outbreak of the coronavirus disease (COVID-19) has left the world clueless. As the WHO declares this new contagion as a pandemic on the 11th of March 2020, the alarming rate of the spawn of the disease in such a short period has disarranged the globe. Standing against this situation researchers are strenuously searching for the key traits responsible for this pandemic. As knowledge regarding the dynamics and host-path interaction of COVID-19 causing Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is currently unknown, the formulation of strategies concerning antiviral treatment, vaccination, and epidemiological control stands crucial. Before designing adequate therapeutic strategies, it is extremely essential to diagnose the disease at the outset as early detection can have a greater impact on building health system capacity. Hence, a comprehensive review of strategies for COVID-19 diagnosis is essential in this existing global situation. In this review, sequentially, we have provided the clinical details along with genetic and proteomic biomarkers related to COVID-19. The article systematically enlightens a clear overview of the clinically adopted techniques for the detection of COVID-19 including oligonucleotide-based molecular detection, Point-of-Care immunodiagnostics, radiographical analysis/sensing system, and newly developed biosensing prototypes having commercial viability. The commercial kits/analytical methods based-sensing strategies have also been tabulated categorically. The critical insights on the developer, commercial brand name, detection methods, technical operational details, detection time, clinical specimen, status, the limit of detection/detection ability have been discussed comprehensively. We believe that this review may provide scientists, clinicians and healthcare manufacturers valuable information regarding the most recent developments/approaches towards COVID-19 diagnosis.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/métodos , Infecções por Coronavirus/diagnóstico , Dispositivos Lab-On-A-Chip , Pneumonia Viral/diagnóstico , Testes Imediatos , Animais , Anticorpos Imobilizados/química , Betacoronavirus/genética , Biomarcadores/análise , Técnicas Biossensoriais/instrumentação , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Infecções por Coronavirus/sangue , Infecções por Coronavirus/virologia , Desenho de Equipamento , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Nanoestruturas/química , Pandemias , Pneumonia Viral/sangue , Pneumonia Viral/virologia , Intensificação de Imagem Radiográfica/instrumentação , Intensificação de Imagem Radiográfica/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/instrumentação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos
6.
Medicine (Baltimore) ; 99(26): e20804, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32590765

RESUMO

The aim of this study was to evaluate the effect of a novel 4-dimensional similarity filter (4DSF) on quantitative and qualitative parameters of low-dose dynamic myocardial computed tomography perfusion (CTP) images.In this retrospective study, medical records of 32 patients with suspected or known coronary artery disease who underwent dynamic myocardial CTP at 80 kV were included. The 4DSF reduces noise by averaging voxels that have similar dynamic behavior after adaptive iterative dose reduction 3D (AIDR3D) and deformable image registration were applied. Qualitative (artefact, contour sharpness, and myocardial homogeneity [1 = poor; 2 = intermediate; 3 = good]) and quantitative measurement (standard deviation [SD] and signal-to-noise ratio [SNR]) were compared between the 4DSF and AIDR3D. Contrast-to-noise ratio (CNR) between ischemic and normal remote myocardium was also assessed using myocardial perfusion magnetic resonance imaging as the reference standard in seven patients.The 4DSF was successfully applied to all the images. Improvement in subjective image quality yielded by 4DSF was higher than that yielded by AIDR3D (homogeneity, 1.0 [3 vs 2]; artefact, 1.5 [3 vs 1.5]; P < .001) in all patients. The 4DSF significantly decreased the SD by 59% (AIDR3D vs 4DSF: 33.5 ±â€Š0.4 vs 13.8 ±â€Š0.4, P < .001), increased the SNR by 134% (AIDR3D vs 4DSF: 4.4 ±â€Š0.2 vs 10.3 ±â€Š0.2, P < .001), and increased the CNR by 131% (AIDR3D vs 4DSF: 1.6 ±â€Š0.2 vs 3.7 ±â€Š0.2, P < .001).The 4DSF improved the qualitative and quantitative parameters of low-dose dynamic myocardial CTP images.


Assuntos
Doença da Artéria Coronariana/diagnóstico , Imagem de Perfusão do Miocárdio/métodos , Tomografia Computadorizada por Raios X , Feminino , Humanos , Japão , Masculino , Registros Médicos/estatística & dados numéricos , Pessoa de Meia-Idade , Melhoria de Qualidade , Intensificação de Imagem Radiográfica/métodos , Saúde Radiológica , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos
7.
AJR Am J Roentgenol ; 215(2): 488-493, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32406770

RESUMO

OBJECTIVE. The aim of this study was to develop a low-dose radiography protocol for the neonatal ICU (NICU) using a new mobile digital radiography system with advanced denoising image processing and to evaluate the noninferiority of that protocol. SUBJECTS AND METHODS. In this prospective randomized study, 40 neonates in the NICU underwent radiography of the thorax and abdomen with two different mobile radiography units: conventional technique on one unit (50 kV, 1.6 mAs, and no additional filtration) and a new technique on another unit (54 kV, 0.1-mm Cu filtration). Three low-dose protocols for the second unit were developed in a phantom study: protocol A (100% equivalent dose with conventional protocol), protocol B (80% equivalent dose), and protocol C (64% equivalent dose). The noninferiority of each low-dose protocol was assessed by three independent readers using image quality criteria. RESULTS. Forty patients each underwent three pairs of radiography examinations (protocol A and the conventional protocol, protocol B and the conventional protocol, and protocol C and the conventional protocol), except one pair that did not include one image of the conventional protocol. The interrater reliability among the three readers was 0.91 (p < 0.001). Both of the low-dose protocols (B and C) were statistically noninferior to the conventional protocol with respect to overall image quality. Protocol B better depicted almost all anatomic landmarks and had better overall image quality than the conventional protocol. CONCLUSION. Using appropriate technique and acquisition factors, radiation dose can be lowered on a digital radiography system without significant effect on the image quality by adding filtrations and a new denoising technique.


Assuntos
Intensificação de Imagem Radiográfica/métodos , Intensificação de Imagem Radiográfica/normas , Protocolos Clínicos , Feminino , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Imagens de Fantasmas , Estudos Prospectivos , Doses de Radiação , Método Simples-Cego
8.
Occup Environ Med ; 77(9): 597-602, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32471837

RESUMO

OBJECTIVES: To investigate the potential of deep learning in assessing pneumoconiosis depicted on digital chest radiographs and to compare its performance with certified radiologists. METHODS: We retrospectively collected a dataset consisting of 1881 chest X-ray images in the form of digital radiography. These images were acquired in a screening setting on subjects who had a history of working in an environment that exposed them to harmful dust. Among these subjects, 923 were diagnosed with pneumoconiosis, and 958 were normal. To identify the subjects with pneumoconiosis, we applied a classical deep convolutional neural network (CNN) called Inception-V3 to these image sets and validated the classification performance of the trained models using the area under the receiver operating characteristic curve (AUC). In addition, we asked two certified radiologists to independently interpret the images in the testing dataset and compared their performance with the computerised scheme. RESULTS: The Inception-V3 CNN architecture, which was trained on the combination of the three image sets, achieved an AUC of 0.878 (95% CI 0.811 to 0.946). The performance of the two radiologists in terms of AUC was 0.668 (95% CI 0.555 to 0.782) and 0.772 (95% CI 0.677 to 0.866), respectively. The agreement between the two readers was moderate (kappa: 0.423, p<0.001). CONCLUSION: Our experimental results demonstrated that the deep leaning solution could achieve a relatively better performance in classification as compared with other models and the certified radiologists, suggesting the feasibility of deep learning techniques in screening pneumoconiosis.


Assuntos
Aprendizado Profundo , Pneumoconiose/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Idoso , China , Poeira , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Redes Neurais de Computação , Exposição Ocupacional/efeitos adversos , Curva ROC , Radiografia Torácica/métodos , Radiologistas , Reprodutibilidade dos Testes , Estudos Retrospectivos
9.
Jpn J Radiol ; 38(6): 547-552, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32239373

RESUMO

PURPOSE: Hepatic infarction is a relatively rare life-threatening complication after pancreatoduodenectomy (PD). Computed tomography (CT) findings and risk factors for hepatic infarctions after PD were investigated. METHODS: One hundred-fifty three patients who underwent contrast-enhanced CT (CECT) after PD between January 2011 and August 2016 were retrospectively analyzed. Hepatic infarction was defined as the non-contrast enhanced area expanding to the liver surface without mass effect on CECT. The relationships between infarctions and preoperative laboratory data or surgical procedures using uni- and multivariate analyses were examined. RESULTS: Twenty-nine patients showed 47 hepatic infarctions on CT. Infarctions most commonly appeared in segment 7 (S7) (17 lesions, 36.2%). Lesions were wedge-shaped in 12 patients and spread over multiple hepatic segments in 11 patients. Univariate analysis identified celiac artery (CA) or common hepatic artery (CHA) resection (p = 0.0029) and portal vein (PV) resection (p = 0.013) as risk factors for infarctions. CA or CHA resection (p = 0.038) remained as a significant factor after multivariate logistic analysis. CONCLUSIONS: Hepatic infarctions after PD were most frequently seen in S7 and PV penetrating sign was characteristic CT findings. CA or CHA resection or PV resection were revealed as risk factors for hepatic infarctions.


Assuntos
Meios de Contraste , Infarto Hepático/diagnóstico por imagem , Pancreaticoduodenectomia , Complicações Pós-Operatórias/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Artéria Hepática/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Veia Porta/diagnóstico por imagem , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
10.
Respir Investig ; 58(3): 169-176, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32146120

RESUMO

BACKGROUND: No study has investigated the capability of high-resolution computed tomography (HRCT) to detect a lateral bronchus abnormality, degree of air bronchogram, and distribution of affected lesions in the diagnosis of Mycoplasma pneumoniae pneumonia (MPP). METHODS: We prospectively enrolled patients with serologically-confirmed MPP or culture-confirmed other bacterial pneumonia (OBP). The distribution of affected areas, abnormalities in lateral bronchial lesions, the degree of air bronchogram, and previously reported findings on HRCT were evaluated for MPP and OBP. Predictive HRCT findings for MPP were determined by logistic regression analysis. We provisionally designed our HRCT criteria (negative, probable, or highly suspected) for diagnosing MPP and investigated the diagnostic yield of the HRCT criteria. RESULTS: Sixty-three MPP and 126 OBP patients were included in this study. Logistic regression analysis showed that the absence of peripheral predominance, bronchial wall thickening, lateral bronchial wall thickening, intralobular or lobular ground-glass opacities, intralobular ground-glass opacities connected to a lateral bronchus, and less air bronchogram in infiltrates were significant predictors of MPP. Our HRCT criteria showed that the sensitivity and specificity in negative, probable, and highly suspected MPP were 0.0 and 0.33, 1.0 and 0.69, and 0.5 and 0.98, respectively. CONCLUSIONS: HRCT had considerable ability to detect a lateral bronchial abnormality and to diagnose or rule out MPP based on the distribution of affected areas, abnormalities in lateral bronchial lesions, and the degree of air bronchogram in the infiltrates.


Assuntos
Brônquios/diagnóstico por imagem , Pneumonia por Mycoplasma/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Broncografia , Diagnóstico Diferencial , Humanos , Pneumonia Bacteriana/diagnóstico por imagem
11.
Phys Med Biol ; 65(9): 095013, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32191923

RESUMO

A rigorous 2D analysis of signal and noise transfer applied to reconstructed planes in digital breast tomosynthesis (DBT) is necessary for system characterization and optimization. This work proposes a method for assessing technical image quality and system detective quantum efficiency (DQEsys) for reconstructed planes in DBT. Measurements of 2D in-plane modulation transfer function (MTF) and noise power spectrum (NPS) were made on five DBT systems using different acquisition parameters, reconstruction algorithms and plane spacing. This work develops the noise equivalent quanta (NEQ), DQEsys and detectability index (d') calculated using a non-prewhitening model observer with eye filter (NPWE) for reconstructed DBT planes. The images required for this implementation were acquired using a homogeneous test object of thickness 40 mm poly(methyl) methacrylate plus 0.5 mm Al; 2D MTF was calculated from an Al disc of thickness 0.2 mm and diameter 50 mm positioned within the phantom. The radiant contrast of the MTF disc and the air kerma at the system input were used as normalization factors. The NPWE detectability index was then compared to the in-plane contrast-detail (c-d) threshold measured using the CDMAM phantom. The MTF and NPS measured on the different systems showed a strong anisotropy, consistent with the cascaded models developed in the literature for DBT. Detectability indices calculated from the measured MTF and NPS successfully predicted changes in c-d detectability for details between 0.1 mm and 2.0 mm, for DBT plane spacings between 0.5 mm and 10 mm, and for air kerma values at the system input between 157 µGy and 1170 µGy. The linear Pearson correlation between the detectability index and threshold gold thickness of the CDMAM phantom was -0.996. The method implements a parametric means of assessing the technical image quality of reconstructed DBT planes, providing valuable information for optimization of DBT systems.


Assuntos
Algoritmos , Mama/diagnóstico por imagem , Mamografia/métodos , Imagens de Fantasmas , Controle de Qualidade , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/normas , Feminino , Humanos
12.
Br J Radiol ; 93(1110): 20190675, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32208973

RESUMO

OBJECTIVE: The purpose of this study was to evaluate the image quality in virtual monochromatic imaging (VMI) at 40 kilo-electron volts (keV) with three-dimensional iterative image reconstruction (3D-IIR). METHODS: A phantom study and clinical study (31 patients) were performed with dual-energy CT (DECT). VMI at 40 keV was obtained and the images were reconstructed using filtered back projection (FBP), 50% adaptive statistical iterative reconstruction (ASiR), and 3D-IIR. We conducted subjective and objective evaluations of the image quality with each reconstruction technique. RESULTS: The image contrast-to-noise ratio and image noise in both the clinical and phantom studies were significantly better with 3D-IIR than with 50% ASiR, and with 50% ASiR than with FBP (all, p < 0.05). The standard deviation and noise power spectra of the reconstructed images decreased in the order of 3D-IIR to 50% ASiR to FBP, while the modulation transfer function was maintained across the three reconstruction techniques. In most subjective evaluations in the clinical study, the image quality was significantly better with 3D-IIR than with 50% ASiR, and with 50% ASiR than with FBP (all, p < 0.001). Regarding the diagnostic acceptability, all images using 3D-IIR were evaluated as being fully or probably acceptable. CONCLUSIONS: The quality of VMI at 40 keV is improved by 3D-IIR, which allows the image noise to be reduced and structural details to be maintained. ADVANCES IN KNOWLEDGE: The improvement of the image quality of VMI at 40 keV by 3D-IIR may increase the subjective acceptance in the clinical setting.


Assuntos
Imageamento Tridimensional/métodos , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Razão Sinal-Ruído , Idoso , Feminino , Humanos , Imageamento Tridimensional/instrumentação , Masculino , Pessoa de Meia-Idade , Melhoria de Qualidade , Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/instrumentação , Tomografia Computadorizada por Raios X/métodos
13.
Jt Dis Relat Surg ; 31(1): 2-7, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160486

RESUMO

OBJECTIVES: This study aims to introduce a new low-cost universal laser aiming device (LAD) that can be used in existing C-arm fluoroscopy devices, independent of brand and model, and to determine whether this new universal LAD improves technician accuracy in locating the desired region at the midpoint of the fluoroscopic image. MATERIALS AND METHODS: A low-priced universal LAD that is compatible with existing 12-inch C-arm fluoroscopy devices was designed. Eight radiology technicians with varied levels of experience in C-arm fluoroscopy participated in the study. A 12 mm cortical screw with a diameter of 3.5 mm was placed on proximal, diaphyseal, and distal points of femur, tibia, and humerus bones in the anteroposterior plane on L3 vertebrae and the left pubis arm in the pelvis bone model. Technicians were asked to align each screw in the image center 10 times from a distance of 30 cm in the anterolateral plane, first without the LAD and then with the LAD. The distance of the screw head to the center point was measured from the 3,520 images with the help of medical viewer software based on the X- and Y-axis. RESULTS: Each fluoroscopic image was divided into 48 equal parts and the length of a part was taken as one unit for distance measurements. The compliance between technicians without the LAD was 0.347 (95% confidence interval [CI]: 0.208-0.47, p=0.001) and with the LAD was 0.687 (95% CI: 0.621-0.741, p=0.001). The distance between the screw head and the center of the image without the LAD was 19.0±9.8 for technicians with more than 10 years of experience and 28.0±12.9 for those with less than 10 years of experience. This difference was statistically significant (p=0.001). When the LAD was used, the difference between the less experienced (3.1±1.5) and more experienced (3.3±2.0) technicians was statistically reduced, along with the distance (p=0.033). CONCLUSION: The use of the LAD with C-arm fluoroscopy appears to be successful in helping technicians capture the desired point in the center of the fluoroscopic image. The use of the LAD reduces the experience gap between technicians.


Assuntos
Fluoroscopia , Lasers , Vértebras Lombares/diagnóstico por imagem , Intensificação de Imagem Radiográfica , Parafusos Ósseos , Desenho de Equipamento , Fluoroscopia/instrumentação , Fluoroscopia/métodos , Humanos , Cuidados Intraoperatórios/instrumentação , Cuidados Intraoperatórios/métodos , Procedimentos Ortopédicos/instrumentação , Procedimentos Ortopédicos/métodos , Procedimentos Ortopédicos/normas , Ossos Pélvicos/diagnóstico por imagem , Intensificação de Imagem Radiográfica/instrumentação , Intensificação de Imagem Radiográfica/métodos
14.
J Comput Assist Tomogr ; 44(2): 197-203, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32195798

RESUMO

INTRODUCTION: Liver segmentation and volumetry have traditionally been performed using computed tomography (CT) attenuation to discriminate liver from other tissues. In this project, we evaluated if spectral detector CT (SDCT) can improve liver segmentation over conventional CT on 2 segmentation methods. MATERIALS AND METHODS: In this Health Insurance Portability and Accountability Act-compliant institutional review board-approved retrospective study, 30 contrast-enhanced SDCT scans with healthy livers were selected. The first segmentation method is based on Gaussian mixture models of the SDCT data. The second method is a convolutional neural network-based technique called U-Net. Both methods were compared against equivalent algorithms, which used conventional CT attenuation, with hand segmentation as the reference standard. Agreement to the reference standard was assessed using Dice similarity coefficient. RESULTS: Dice similarity coefficients to the reference standard are 0.93 ± 0.02 for the Gaussian mixture model method and 0.90 ± 0.04 for the CNN-based method (all 2 methods applied on SDCT). These were significantly higher compared with equivalent algorithms applied on conventional CT, with Dice coefficients of 0.90 ± 0.06 (P = 0.007) and 0.86 ± 0.06 (P < 0.001), respectively. CONCLUSION: On both liver segmentation methods tested, we demonstrated higher segmentation performance when the algorithms are applied on SDCT data compared with equivalent algorithms applied on conventional CT data.


Assuntos
Fígado/diagnóstico por imagem , Fígado/patologia , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste , Humanos , Tamanho do Órgão , Intensificação de Imagem Radiográfica/métodos , Estudos Retrospectivos
15.
J Comput Assist Tomogr ; 44(2): 209-216, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32195799

RESUMO

PURPOSE: The aim of this study was to compare hepatic vascular and parenchymal image quality between direct and peristaltic contrast injectors during hepatic computed tomography (HCT). METHODS: Patients (n = 171) who underwent enhanced HCT and had both contrast media protocols and injector systems were included; group A: direct-drive injector with fixed 100 mL contrast volume (CV), and group B: peristaltic injector with weight-based CV. Opacification, contrast-to-noise ratio, signal-to-noise ratio, radiation dose, and CV for liver parenchyma and vessels in both groups were compared by paired t test and Pearson correlation. Receiver operating characteristic curve, visual grading characteristics, and Cohen κ were used. RESULTS: Contrast-to-noise ratio: compared with hepatic vein for functional liver, contrast-to-noise ratio was higher in group B (2.17 ± 0.83) than group A (1.82 ± 0.63); portal vein: higher in group B (2.281 ± 0.96) than group A (2.00 ± 0.66). Signal-to-noise ratio for functional liver was higher in group B (5.79 ± 1.58 Hounsfield units) than group A (4.81 ± 1.53 Hounsfield units). Radiation dose and contrast media were lower in group B (1.98 ± 0.92 mSv) (89.51 ± 15.49 mL) compared with group A (2.77 ± 1.03 mSv) (100 ± 1.00 mL). Receiver operating characteristic curve demonstrated increased reader in group B (95% confidence interval, 0.524-1.0) than group A (95% confidence interval, 0.545-1.0). Group B had increased revenue up to 58% compared with group A. CONCLUSIONS: Image quality improvement is achieved with lower CV and radiation dose when using peristaltic injector with weight-based CV in HCT.


Assuntos
Meios de Contraste/administração & dosagem , Fígado/diagnóstico por imagem , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Feminino , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
16.
J Comput Assist Tomogr ; 44(2): 223-229, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32195800

RESUMO

OBJECTIVES: This study aimed to assess if dual-energy computed tomography (DECT) quantitative analysis and radiomics can differentiate normal liver, hepatic steatosis, and cirrhosis. MATERIALS AND METHODS: Our retrospective study included 75 adult patients (mean age, 54 ± 16 years) who underwent contrast-enhanced, dual-source DECT of the abdomen. We used Dual-Energy Tumor Analysis prototype for semiautomatic liver segmentation and DECT and radiomic features. The data were analyzed with multiple logistic regression and random forest classifier to determine area under the curve (AUC). RESULTS: Iodine quantification (AUC, 0.95) and radiomic features (AUC, 0.97) differentiate between healthy and abnormal liver. Combined fat ratio percent and mean mixed CT values (AUC, 0.99) were the strongest differentiators of healthy and steatotic liver. The most accurate differentiating parameters of normal liver and cirrhosis were a combination of first-order statistics (90th percentile), gray-level run length matrix (short-run low gray-level emphasis), and gray-level size zone matrix (gray-level nonuniformity normalized; AUC, 0.99). CONCLUSION: Dual-energy computed tomography iodine quantification and radiomics accurately differentiate normal liver from steatosis and cirrhosis from single-section analyses.


Assuntos
Fígado Gorduroso/diagnóstico por imagem , Cirrose Hepática/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste , Diagnóstico Diferencial , Estudos de Avaliação como Assunto , Feminino , Humanos , Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Intensificação de Imagem Radiográfica/métodos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Estudos Retrospectivos
17.
J Comput Assist Tomogr ; 44(2): 230-235, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32195801

RESUMO

OBJECTIVE: We developed a patient-specific contrast enhancement optimizer (p-COP) that can exploratorily calculate the contrast injection protocol required to obtain optimal enhancement at target organs using a computer simulator. Appropriate contrast media dose calculated by the p-COP may minimize interpatient enhancement variability. Our study sought to investigate the clinical utility of p-COP in hepatic dynamic computed tomography (CT). METHODS: One hundred thirty patients (74 men, 56 women; median age, 65 years) undergoing hepatic dynamic CT were randomly assigned to 1 of 2 contrast media injection protocols using a random number table. Group A (n = 65) was injected with a p-COP-determined iodine dose (developed by Higaki and Awai, Hiroshima University, Japan). In group B (n = 65), a standard protocol was used. The variability of measured CT number (SD) between the 2 groups of aortic and hepatic enhancement was compared using the F test. In the equivalence test, the equivalence margins for aortic and hepatic enhancement were set at 50 and 10 Hounsfield units (HU), respectively. The rate of patients with an acceptable aortic enhancement (250-350 HU) for the diagnosis of hypervascular liver tumors was compared using the χ test. RESULTS: The mean ± SD values of aortic and hepatic enhancement were 311.0 ± 39.9 versus 318.7 ± 56.5 and 59.0 ± 11.5 versus 58.6 ± 11.8 HU in groups A and B, respectively. Although the SD for aortic enhancement was significantly lower in group A (P = 0.006), the SD for hepatic enhancement was not significantly different (P = 0.871). The 95% confidence interval for the difference in aortic and hepatic enhancement between the 2 groups was within the range of the equivalence margins. The number of patients with acceptable aortic enhancement was significantly greater in group A than in group B (P < 0.01). CONCLUSIONS: The p-COP software reduced interpatient variability in aortic enhancement and obtained acceptable aortic enhancement at a significantly higher rate compared with the standard injection protocol for hepatic dynamic CT.


Assuntos
Meios de Contraste/administração & dosagem , Iohexol/administração & dosagem , Neoplasias Hepáticas/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Injeções Intravenosas , Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
18.
J Comput Assist Tomogr ; 44(2): 242-247, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32195803

RESUMO

OBJECTIVE: The objective of this study was to assess if bowel wall iodine density obtained from dual-source, dual-energy computed tomography enterography (DECTE) could be a biomarker of Crohn's disease activity. METHODS: Twenty-two patients with Crohn's disease imaged with DECTE from February 2016 to May 2018 were retrospectively identified by departmental report search. Iodine maps were created with commercial software (Syngovia). Iodine content was normalized to the aorta, and then manual dual-energy region-of-interest cursors were placed over the visibly assessed maximal and minimal iodine density within segments of involved as well as unaffected small bowel. The mixed Hounsfield unit value, maximum iodine density (Imax), and minimum iodine density (Imin) were recorded. The length of affected bowel demonstrating maximum disease activity as a percentage of overall involvement was subjectively assessed. A weighted iodine density (Iweighted) was calculated. The clinical assessment of disease activity using erythrocyte sedimentation rate, C-reactive protein, fecal calprotectin, colonoscopy/endoscopy, and surgery, if available, served as the reference standard. The Crohn's disease activity index was also used as a separate additional reference standard. RESULTS: Significant heterogeneity within the affected segments was present. The average Imax and Imin of affected bowel was 4.27 ± 1.11 (2.4-7.4) mg/mL and 2.71 ± 0.51 (2.2-3.9) mg/mL, respectively. Iodine density of normal-appearing small bowel was 1.40 ± 0.26 (0.9-1.9) mg/mL. The Imax and Imin of affected bowel differed significantly from normal bowel (P < 0.0001). Mixed Hounsfield unit (101.82 ± 27.5) also statistically differed (46.33 ± 19.62) (P < 0.0001). Using overall clinical assessment as the reference standard, all patients with Imin of greater than 2.6 mg/mL, Iweighted of greater than 3.3 mg/mL, or Imax of greater than 4.7 mg/mL had clinically active disease. Sixteen of 17 patients with Imin of greater than 2.2 mg/mL and 14/15 with Iweighted of greater than 3 mg/mL had clinically active disease. Using Crohn's disease activity index as the reference standard, all patients with Imin of greater than 2.7 mg/mL, Iweighted of greater than 3.6 mg/mL, or Imax of greater than 5.4 mg/mL had clinically active disease. The median effective dose was 4.64 ± 1.68 mSv (range, 2.03-8.12 mSv). CONCLUSIONS: Iodine density obtained from DECTE highlights regions of maximal activity within affected bowel segments. An iodine density of 2 mg/mL appears to be a threshold between normal bowel segments and those with active Crohn's disease. Iodine density measurement thresholds Imin of greater than 2.6 mg/mL, Iweighted of greater than 3.3 mg/mL, and Imax of greater than 4.7 mg/mL correlate with established clinical markers of disease activity, with Imin seemingly most useful in daily clinical practice.


Assuntos
Meios de Contraste , Doença de Crohn/diagnóstico por imagem , Intestinos/diagnóstico por imagem , Iodo , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Absorciometria de Fóton , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
19.
Medicine (Baltimore) ; 99(11): e19268, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32176050

RESUMO

The purpose of this study was to investigate metal artifact reduction effect of orthopedics metal artifact reduction (O-Mar) algorithm in computer tomography (CT) image of patients who have undergone total hip arthroplasty (THA) or total knee arthroplasty (TKA).35 cases of patients who underwent TKA or THA have been recruited in this study. CT image of hip or knee joint was obtained with Philips 256-row CT scanner. Tube voltages of 120 and 140 kilovolt peak (KVP) were set. Afterwards, CT image was reconstructed by O-Mar algorithm to reduce metal artifact. Grade of image quality and severity of metal artifact would be taken into qualitative evaluation. While, quantitative evaluation mainly included measurement of metal artifact volume and 2D measurement of average CT value in region of interest (ROI). The visibility of interface between bone-prostheses was also estimated.Result of qualitative analysis indicated that score of CT quality was improved and grade of metal artifact was decreased significantly with O-Mar. Quantitative analysis illustrated that volume of beam-hardening (B-H) metal artifact decreased remarkably after reconstruction of O-Mar (P < .001). In addition, O-Mar algorithm reduced 83.3% to 83.7% volume of photon-starvation (P-S) metal artifact. As for result of 2D measurement, CT value in ROI was closer to standard value in O-Mar group CT image (P < .001). Meanwhile, error of CT value also decreased significantly after reconstruction of O-Mar algorithm. Visibility rate of bone-prosthesis interface improved from 34.3% (Non-O-Mar) to 66.7% (O-Mar).O-Mar algorithm could significantly reduce metal artifact in CT image of THA and TKA in both 2D and three-dimensional (3D) level. Therefore, better image quality and visibility of bone-prostheses interface could be presented. In this study, O-Mar was proved as an efficient metal artifact reduction method in CT image of THA and TKA.


Assuntos
Algoritmos , Artroplastia de Quadril/métodos , Artroplastia do Joelho/métodos , Artefatos , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Prótese do Joelho , Masculino , Metais , Pessoa de Meia-Idade , Ortopedia , Estudos Retrospectivos
20.
Neural Netw ; 124: 269-279, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32035306

RESUMO

Deformable image registration is a fundamental problem in the field of medical image analysis. During the last years, we have witnessed the advent of deep learning-based image registration methods which achieve state-of-the-art performance, and drastically reduce the required computational time. However, little work has been done regarding how can we encourage our models to produce not only accurate, but also anatomically plausible results, which is still an open question in the field. In this work, we argue that incorporating anatomical priors in the form of global constraints into the learning process of these models, will further improve their performance and boost the realism of the warped images after registration. We learn global non-linear representations of image anatomy using segmentation masks, and employ them to constraint the registration process. The proposed AC-RegNet architecture is evaluated in the context of chest X-ray image registration using three different datasets, where the high anatomical variability makes the task extremely challenging. Our experiments show that the proposed anatomically constrained registration model produces more realistic and accurate results than state-of-the-art methods, demonstrating the potential of this approach.


Assuntos
Aprendizado Profundo , Intensificação de Imagem Radiográfica/métodos , Humanos , Intensificação de Imagem Radiográfica/normas
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