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1.
J Comput Assist Tomogr ; 44(1): 7-12, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939875

RESUMO

OBJECTIVE: The aim of the study was to investigate the feasibility of coronary computed tomography (CT) angiography with a low kilovoltage peak scan and a refined scan timing prediction using a small contrast medium (CM) dose. METHODS: In protocol A, 120-kVp scanning and a standard CM dose were used. The scan timing was fixed. In protocol B, 80 kVp and a 60% CM dose were used. The scan timing was determined according to the interval from the CM arrival to the peak time in the ascending aorta. We measured the CT number and recorded the radiation dose. RESULTS: Higher CT numbers were observed in the left circumflex (proximal, P = 0.0235; middle, P = 0.0007; distal, P < 0.0001) in protocol B compared with protocol A. The radiation dose in protocol B was significantly lower than in protocol A (2.2 ± 0.9 vs 4.3 ± 1.7 mSv). CONCLUSIONS: Low-contrast, low-radiation dose, high-image quality coronary CT angiography can be performed with low kilovoltage peak scanning and a refined scan timing prediction.


Assuntos
Angiografia por Tomografia Computadorizada/métodos , Meios de Contraste/administração & dosagem , Doença da Artéria Coronariana/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Idoso , Cálculos da Dosagem de Medicamento , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Estudos Retrospectivos
3.
Radiol Med ; 124(12): 1229-1237, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31773458

RESUMO

The aim of our study was to assess the performance of contrast-enhanced digital mammography (CEDM) in the preoperative loco-regional staging of invasive lobular carcinoma (ILC) patients, about the valuation of the extension of disease and in measurement of lesions. Then, we selected retrospectively, among the 1500 patients underwent to CEDM at the Breast Diagnostics Department of the Careggi University Hospital of Florence and the National Cancer Institute of Milan from September 2016 to November 2018, 31 women (mean age 57.1 aa; range 41-78 aa) with a definitive histological diagnosis of ILC. CEDM has proved to be a promising imaging technique, being characterized by a sensitivity of 100% in the detection of the index lesion, and of 84.2% in identifying any adjunctive lesions: It was the presence of a non-mass enhancement (NME) to lower the sensitivity of the technique (25% vs. 100% for mass-like enhancements or a mass closely associated with a NME). Specificity in the characterization of additional lesions was 66.7%, and the diagnosis of the extension of disease was correct in 77.4% of cases: NME also led to a decrease in diagnostic accuracy in the evaluation of disease extension up to 40% versus 85% for masses and 80% for masses associated with NME (M/NME). Moreover, in 12/31 (38.7%), CEDM allowed to correctly identify lesions not shown by mammography + ultrasonography + tomosynthesis: In the half of these (6/12), there was a multicentricity, thus allowing an adequate surgical planning change. CEDM was also very accurate in analyzing the maximum diameter of the masses, while it was much less reliable in the case of the M/NME and pure NME. In conclusion, CEDM is a new promising imaging technique in the loco-regional preoperative staging and in the evaluation of disease extension for ILC, especially in case of mass enhancement lesions.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Carcinoma Lobular/diagnóstico por imagem , Meios de Contraste , Iohexol/análogos & derivados , Mamografia/métodos , Adulto , Idoso , Neoplasias da Mama/química , Neoplasias da Mama/patologia , Carcinoma Lobular/química , Carcinoma Lobular/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias/métodos , Cuidados Pré-Operatórios , Intensificação de Imagem Radiográfica/métodos , Padrões de Referência , Estudos Retrospectivos , Sensibilidade e Especificidade , Carga Tumoral , Ultrassonografia Mamária
4.
Medicine (Baltimore) ; 98(47): e17902, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31764788

RESUMO

PURPOSE: To assess the probability of achieving optimal contrast enhancement in 100 kVp and 120 kVp-protocol on hepatic computed tomography (CT) scans. MATERIALS AND METHODS: We enrolled 200 patients in a retrospective cohort study. Hundred patients were scanned with 120 kVp setting, and other 100 patients were scanned with 100 kVp setting. We measured the CT number in the abdominal aorta and hepatic parenchyma on unenhanced scans and hepatic arterial phase (HAP)-, and portal venous phase (PVP). The aortic enhancement at HAP and the hepatic parenchymal enhancement at PVP were compared between the two scanning protocols. Bayesian inference was used to assess the probability of achieving optimal contrast enhancement in each protocol. RESULTS: The Bayesian analysis indicated that when 100 kVp-rotocol was used, the probability of achieving optimal aortic enhancement (>280 HU) was 98.8% ±â€Š0.6%, whereas it was 88.7% ±â€Š2.5% when 120 kVp-protocol was used. Also, the probability of achieving optimal hepatic parenchymal enhancement (>50 HU) was 95.3% ±â€Š1.5%, whereas it was 64.7% ±â€Š3.8% when 120 kVp-protocol was used. CONCLUSION: Bayesian inference suggested that the post-test probability of optimal contrast enhancement at hepatic dynamic CT was lower under the 120 kVp than the 100 kVp-protocol.


Assuntos
Meios de Contraste , Fígado/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Teorema de Bayes , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Magreza
5.
J Comput Assist Tomogr ; 43(6): 877-883, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31688248

RESUMO

PURPOSE: This study aimed to prospectively compare the image quality and visibility of urinary stone on computed tomographic (CT) images at multiple radiation exposure levels from the same patient reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE). METHODS: This study included 760 patients with urinary stone who underwent CT with simultaneous acquisition at 6 exposures per patient (100% filtered back projection, 75%, 50%, 37.5%, 25%, and 12.5% SAFIRE). Two radiologists independently assessed overall image quality, noise, and stone visibility by using a 5-point scale. Quantitative measurements, including the CT number, image noise, signal-to-noise ratio, contrast-to-noise ratio (CNR), and corresponding figure of merit (FOM), were compared for 100% versus 5 other radiation doses. RESULTS: Qualitative overall image quality, noise, and stone visibility according to the location were not inferior at 37.5% exposure compared with 100% exposure, except for the visualization of smaller stones <3 mm. The signal-to-noise ratio and CNR of CT images were increased at 50% exposure compared with 100% exposure. Computed tomographic images at 37.5% exposure reconstructed with SAFIRE had significantly more noise and a lower CNR compared with CT images reconstructed with filtered back projection, based on FOMnoise and FOMCNR. The size-specific dose estimation was 4.1 ± 0.8 mGy at 37.5% exposure. CONCLUSION: Computed tomography performed at 37.5% exposure with SAFIRE may be diagnostically acceptable for the detection of clinically relevant stone.


Assuntos
Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Cálculos Urinários/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Doses de Radiação , Razão Sinal-Ruído , Tomografia Computadorizada por Raios X , Adulto Jovem
6.
J Comput Assist Tomogr ; 43(6): 948-952, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31688249

RESUMO

PURPOSE: This study aimed to evaluate the image quality and degree of metal artifact reduction using the new-generation gemstone spectral imaging (GSI) and metal artifact reduction software (MARs) and to demonstrate the optimal monochromatic energy level for dual-energy cerebral computed tomography angiography (CTA) in patients with intracranial aneurysm after endovascular treatment. MATERIAL AND METHODS: A total of 20 patients with cerebral aneurysms treated with coils or clips underwent CTA using gemstone spectral computed tomography. Artifact index was calculated at each energy level with and without MARs. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated on all axial images with MARs; subjective evaluation was done by using a 4-point scale and a 3-point scale for assessing noise and vessel contrast, respectively, and compared between the monochromatic energy levels. RESULTS: The artifact index value of group GSI-MARs was significantly lower than that of group GSI at each monochromatic energy level (all, P < 0.01). Contrast-to-noise ratio and SNR of the parent arteries decreased as the energy increased from 40 to 140 keV in group GSI-MARs (all, P < 0.01). Signal-to-noise ratio and CNR between each 2 adjacent monochromatic energy level showed significant difference (all, P < 0.01). Subjective evaluation showed that a monochromatic energy level between 40 and 70 keV provided the optimal image quality. CONCLUSION: Gemstone spectral imaging with MARs could reduce metal artifacts and improve the image quality of cerebral CTA after coil or clip treatment. The new generation of GSI could provide better CNR and SNR at lower energy level, and the best image quality was obtained at energy level 40 to 70 keV for GSI-MARs.


Assuntos
Procedimentos Endovasculares/métodos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Intensificação de Imagem Radiográfica/métodos , Adulto , Idoso , Artefatos , Angiografia por Tomografia Computadorizada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Estudos Retrospectivos , Razão Sinal-Ruído , Software
7.
Urology ; 134: 84-89, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31585199

RESUMO

OBJECTIVE: To investigate computed tomography (CT) texture analysis of the bladder wall as a predictor of urodynamics findings in adult patient with spina bifida. METHODS: A single-center prospective trial was conducted from March 2015 to March 2017 including all consecutive adult spina bifida patients seen for urodynamic testing. A contrast-enhanced abdominal CT was systematically performed in all patients during the same visit. Texture features of the bladder wall related to the gray-level histogram and gray-level co-occurrence were evaluated on CT images. Multivariate analysis was performed to identify independent predictors of poor bladder compliance and detrusor overactivity among clinical and texture parameters. RESULTS: Fourty patients were included. The Lasso penalized logistic regression analysis identified 2 texture parameters as potential predictors of poor bladder compliance: Skewness (coefficient weight, -1.81) and S.1.1.SumVarnc (coefficient weight, -3.52). Multivariate logistic regression analysis confirmed skewness (odds ratio [confidence interval 95%] = 0.40 [0.14, 0.97], P = .04) as an independent predictor of poor bladder compliance. The Lasso penalized logistic regression analysis identified one texture parameters as potential predictor of detrusor overactivity: Kurtosis (coefficient weight, -3.52), which was confirmed in multivariate logistic regression analysis (odds ratio [confidence interval 95%] = 1.12 [1.01, 1.55], P = .02). CONCLUSION: Our findings demonstrate that CT texture analysis of the bladder wall might be an interesting tool to identify spina bifida patients with high risk urodynamic features.


Assuntos
Disrafismo Espinal , Tomografia Computadorizada por Raios X/métodos , Bexiga Urinária Hiperativa , Bexiga Urinária , Urodinâmica , Adulto , Feminino , França , Humanos , Masculino , Estudos Prospectivos , Intensificação de Imagem Radiográfica/métodos , Disrafismo Espinal/complicações , Disrafismo Espinal/diagnóstico , Disrafismo Espinal/fisiopatologia , Bexiga Urinária/diagnóstico por imagem , Bexiga Urinária/fisiopatologia , Bexiga Urinária Hiperativa/diagnóstico , Bexiga Urinária Hiperativa/etiologia , Bexiga Urinária Hiperativa/fisiopatologia
8.
Medicine (Baltimore) ; 98(39): e17280, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574843

RESUMO

BACKGROUND: This study will aim to evaluate the diagnostic accuracy of digital X-ray radiogrammetry (DXR) on hand bone loss (HBL) for rheumatoid arthritis (RA). METHODS: In this study, we will search the literature from PubMed, EMBASE, Cochrane Library, PsycINFO, Web of Science, Google Scholar, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and WANFANG from the inception to June 1, 2019 without language restrictions. All case-controlled studies on assessing diagnostic accuracy of DXR on HBL for diagnosis of RA will be included. Quality Assessment of Diagnostic Accuracy Studies tool will be used for eligible studies. We will apply RevMan V.5.3 software and Stata V.12.0 software for statistical analysis. RESULTS: We will evaluate diagnostic accuracy of DXR on HBL in patients with RA by assessing the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio. CONCLUSION: This study will detect the diagnostic accuracy of DXR evaluation on HBL in patients with RA. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019139489.


Assuntos
Artrite Reumatoide/diagnóstico por imagem , Doenças Ósseas Metabólicas/diagnóstico por imagem , Densitometria/estatística & dados numéricos , Intensificação de Imagem Radiográfica/métodos , Radiografia/estatística & dados numéricos , Artrite Reumatoide/complicações , Doenças Ósseas Metabólicas/etiologia , Estudos de Casos e Controles , Densitometria/métodos , Progressão da Doença , Feminino , Ossos da Mão/diagnóstico por imagem , Humanos , Masculino , Radiografia/métodos , Projetos de Pesquisa , Índice de Gravidade de Doença , Revisão Sistemática como Assunto
9.
Br J Radiol ; 92(1103): 20190384, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31479307

RESUMO

OBJECTIVE: Evaluation of coronary CT image blur using multi segment reconstruction algorithm. METHODS: Cardiac motion was simulated in a Catphan. CT coronary angiography was performed using 320 × 0.5 mm detector array and 275 ms gantry rotation. 1, 2 and 3 segment reconstruction algorithm, three heart rates (60, 80 and 100bpm), two peak displacements (4, 8 mm) and three cardiac phases (55, 35, 75%) were used. Wilcoxon test compared image blur from the different reconstruction algorithms. RESULTS: Image blur for 1, 2 and 3 segments in: 60 bpm, 75% R-R interval and 8 mm peak displacement: 0.714, 0.588, 0.571 mm (1.18, 0.6, 0.4 mm displacement) 80 bpm, 35% R-R interval and 8 mm peak displacement: 0.869, 0.606, 0.606 mm (1.57, 0.79,0.52 mm displacement) 100 bpm, 35% R-R interval and 4 mm peak displacement: 0.645, 0.588, 0.571 mm (0.98, 0.49, 0.33 mm displacement). The median image blur overall for 1 and 2 segments was 0.714 mm and 0.588 mm respectively (p < 0.0001). CONCLUSION: Two-segment reconstruction significantly reduces image blur. ADVANCES IN KNOWLEDGE: Multisegment reconstruction algorithms during CT coronary angiography are a useful method to reduce image blur, improve visualization of the coronary artery wall and help the early detection of the plaque.


Assuntos
Angiografia por Tomografia Computadorizada/normas , Doença da Artéria Coronariana/diagnóstico por imagem , Algoritmos , Análise de Variância , Artefatos , Doença da Artéria Coronariana/fisiopatologia , Frequência Cardíaca/fisiologia , Humanos , Movimento , Imagens de Fantasmas , Projetos Piloto , Estudos Prospectivos , Intensificação de Imagem Radiográfica/métodos
10.
BMC Oral Health ; 19(1): 206, 2019 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-31484529

RESUMO

BACKGROUND: To determine the accuracy of volumetric measurements of the mandible in vitro by cone-beam computed tomography (CBCT) and to analyze the influence of voxel sizes and segmentation threshold settings on it. METHODS: The samples were obtained from pig mandibles and scanned with 4 voxel sizes: .125 mm, .20 mm, .30 mm, and .40 mm. The minimum segmentation thresholds in Hounsfield units (HU) were set as 0, 100, 200, 300, and 400, respectively, for each voxel size for 3D reconstruction. Laser scanning as the reference, the volumes of each CBCT scanning, the mean iterative distances of superimposition and total positive and negative deviations were recorded and compared. RESULTS: The volumes of CBCT-scan deviated from those of laser-scan by + 7.67% to - 3.05% with different HU and voxel sizes. The deviation increased with the voxel size. There was a more suitable minimum HU threshold of segmentation (HU100 for .125 mm, 200 for .20 mm, 300 for .30 mm, and 400 for .40 mm) for each voxel size. CONCLUSIONS: Voxel sizes and Hounsfield unit thresholds influence the accuracy of volumetric measurements in CBCT scanning. The volume increase with the voxel size, and different voxel sizes correspond to different optimal Hounsfield unit thresholds.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Processamento de Imagem Assistida por Computador/métodos , Imagem Tridimensional/métodos , Mandíbula/diagnóstico por imagem , Radiografia Dentária Digital/métodos , Animais , Simulação por Computador , Lasers , Odontometria , Intensificação de Imagem Radiográfica/métodos , Suínos , Coroa do Dente/diagnóstico por imagem , Raiz Dentária/diagnóstico por imagem
12.
Eur J Radiol ; 118: 130-137, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31439232

RESUMO

PURPOSE: Within paediatric pelvis imaging there is a lack of systematic dose optimisation studies which consider age and size variations. This paper presents data from dose optimisation studies using digital radiography and pelvis phantoms representing 1 and 5-year-old children. MATERIAL AND METHOD: Dose optimisation included assessments of image quality and radiation dose. Systematic variations using a factorial design for acquisition factors (kVp, mAs, source-detector distance [SDD] and filtration) were undertaken to acquire AP pelvis X-ray images. Perceptual image quality was assessed using a relative and absolute visual grading assessment (VGA) method. Radiation doses were measured by placing a dosimeter at the radiographic centring point on the surface of each phantom. Statistical analyses for determining the optimised parameters included main effects analysis. RESULTS: Optimised techniques, with diagnostically acceptable image quality, for each paediatric age were: 1-year-old; 65 kVp, 2 mAs and 115 cm SDD, while, 5-year-old; 62 kVp, 8 mAs and 130 cm SDD both included 1 mm Al +0.1 mm Cu additional filtration. The main effect analysis identified situations in which image quality and radiation dose increased or decreased, except for kVp which showed peak image quality when exposure factors were increased. A set of minimum mAs values for producing diagnostic image quality were identified. Increasing SDD, unlike the other exposure factors, showed no trends for producing non-diagnostic images. CONCLUSION: The factorial design provided an opportunity to identify suitable acquisition factors. This study provided a method for investigating the combined effect of multiple acquisition parameters on image quality and radiation dose for children.


Assuntos
Pelve/efeitos da radiação , Doses de Radiação , Pré-Escolar , Humanos , Lactente , Pelve/diagnóstico por imagem , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/métodos , Radiometria
13.
Radiología (Madr., Ed. impr.) ; 61(4): 274-285, jul.-ago. 2019. ilus, tab, mapas
Artigo em Espanhol | IBECS | ID: ibc-185305

RESUMO

La tomosíntesis de la mama es una herramienta del diagnóstico radiológico que se encuentra en constante desarrollo. En esta actualización sobre tomosíntesis se hace una revisión de las ventajas de la técnica, tanto en mamografía diagnóstica como de cribado, así como de sus limitaciones, entre las que la dosis de radiación es la principal. La aparición más reciente de la mamografía sintetizada, la detección de lesiones asistida por ordenador y la biopsia guiada por tomosíntesis, ha contribuido a reducir la dosis de radiación empleada y a mejorar el rendimiento diagnóstico de la tomosíntesis, motivo por el cual también son objeto de esta revisión


Breast tomosynthesis is a continually improving tool for diagnostic radiologists. This update about tomosynthesis reviews the advantages of the technique both in patients with suspected or known disease and in screening, as well as its limitations, of which the dose of radiation is the most important. The more recent advent of synthesized mammography, computer-assisted detection, and tomosynthesis-guided biopsy have helped to reduce the dose of radiation used and have improved the diagnostic performance of tomosynthesis, so they are also discussed in this review


Assuntos
Humanos , Feminino , Mamografia/métodos , Neoplasias da Mama/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Biópsia Guiada por Imagem/métodos , Neoplasias da Mama/terapia , Detecção Precoce de Câncer/métodos , Doses de Radiação
14.
Medicine (Baltimore) ; 98(29): e16423, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31335694

RESUMO

To test whether texture analysis (TA) can discriminate between Systemic Sclerosis (SSc) and non-SSc patients in computed tomography (CT) with different radiation doses and reconstruction algorithms.In this IRB-approved retrospective study, 85 CT scans at different radiation doses [49 standard dose CT (SDCT) with a volume CT dose index (CTDIvol) of 4.86 ±â€Š2.1 mGy and 36 low-dose (LDCT) with a CTDIvol of 2.5 ±â€Š1.5 mGy] were selected; 61 patients had Ssc ("cases"), and 24 patients had no SSc ("controls"). CT scans were reconstructed with filtered-back projection (FBP) and with sinogram-affirmed iterative reconstruction (SAFIRE) algorithms. 304 TA features were extracted from each manually drawn region-of-interest at 6 pre-defined levels: at the midpoint between lung apices and tracheal carina, at the level of the tracheal carina, and 4 between the carina and pleural recesses. Each TA feature was averaged between these 6 pre-defined levels and was used as input in the machine learning algorithm artificial neural network (ANN) with backpropagation (MultilayerPerceptron) for differentiating between SSc and non-SSc patients.Results were compared regarding correctly/incorrectly classified instances and ROC-AUCs.ANN correctly classified individuals in 93.8% (AUC = 0.981) of FBP-LDCT, in 78.5% (AUC = 0.859) of FBP-SDCT, in 91.1% (AUC = 0.922) of SAFIRE3-LDCT and 75.7% (AUC = 0.815) of SAFIRE3-SDCT, in 88.1% (AUC = 0.929) of SAFIRE5-LDCT and 74% (AUC = 0.815) of SAFIRE5-SDCT.Quantitative TA-based discrimination of CT of SSc patients is possible showing highest discriminatory power in FBP-LDCT images.


Assuntos
Doenças Pulmonares Intersticiais , Pulmão/diagnóstico por imagem , Escleroderma Sistêmico , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Algoritmos , Diagnóstico Diferencial , Diagnóstico Precoce , Feminino , Humanos , Doenças Pulmonares Intersticiais/diagnóstico , Doenças Pulmonares Intersticiais/etiologia , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Escleroderma Sistêmico/complicações , Escleroderma Sistêmico/diagnóstico
15.
Comput Methods Programs Biomed ; 177: 243-252, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31319953

RESUMO

BACKGROUND AND OBJECTIVE: The availability of digital X-ray detectors, together with the development of new robotized hardware and reconstruction algorithms, opens the opportunity to provide 3D capabilities with conventional radiology systems. This would be based on the acquisition of a limited number of projections with non-standard geometrical configurations. The versatility of these techniques is enormous, enabling the introduction of tomography in situations where a CT system is hardly available, such as during surgery or in an ICU, or in which a reduction of radiation dose is key, as in pediatrics. Computer simulations are a valuable tool to explore these possibilities before their actual implementation on real systems. Existing software tools generally simulate only standard acquisition protocols, such as cone-beam with circular trajectory, thus not allowing the users to evaluate more sophisticated projection geometries. The goal of this work is to design a simulation tool that enables the design of acquisition protocols with flexible projection geometries. METHODS: We present XAP-Lab, a software tool for the design of X-ray acquisition protocols with flexible trajectories. For a given projection geometry, defined through a graphical user interface, it allows the user to simulate projections using GPU-accelerated kernels, the visualization of the scanned field of view and the estimation of the total radiation dose. The complete acquisition protocol can then be exported with the appropriate format for its use on real systems. We tested the software by optimizing a tomosynthesis protocol and validating the results with real acquisitions using a SEDECAL NOVA FA radiography system and phantoms for quantitative and qualitative evaluation. RESULTS: Quantitative evaluation using a phantom showed a mean error under 4 mm for each position, below the ±5 mm tolerance of the system specified by the manufacturer. Visual evaluation on a thorax acquisition also showed a good geometrical agreement between simulated and real projections. CONCLUSIONS: Results showed an excellent matching with simulations, supporting the usefulness of XAP-Lab for the design of new acquisition protocols with non-standard geometries.


Assuntos
Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Software , Tórax/diagnóstico por imagem , Algoritmos , Gráficos por Computador , Simulação por Computador , Humanos , Imagens de Fantasmas , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Radiografia Torácica/instrumentação , Robótica , Espalhamento de Radiação , Tomografia Computadorizada por Raios X , Interface Usuário-Computador , Raios X
16.
Eur J Radiol ; 117: 62-68, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31307654

RESUMO

OBJECTIVES: Contrast-enhanced mammography (CEM) was found superior to Full-Field Digital Mammography (FFDM) for breast cancer detection. Current hanging protocols show low-energy (LE, similar to FFDM) images first, followed by recombined (RC) images. However, evidence regarding which hanging protocol leads to the most efficient reading process and highest diagnostic performance is lacking. This study investigates the effects of hanging-protocol ordering on the reading process and diagnostic performance of breast radiologists using eye-tracking methodology. Furthermore, it investigates differences in reading processes and diagnostic performance between LE, RC and FFDM images. MATERIALS AND METHODS: Twenty-seven breast radiologists were randomized into three reading groups: LE-RC (commonly used hangings), RC-LE (reversed hangings) and FFDM. Thirty cases (nine malignant) were used. Fixation count, net dwell time and time-to-first fixation on malignancies as visual search measures were registered by the eye-tracker. Reading time per image was measured. Participants clicked on suspicious lesions to determine sensitivity and specificity. Area-under-the-ROC-curve (AUC) values were calculated. RESULTS: RC-LE scored identical on visual search measures, t(16)= -1.45, p = .17 or higher-p values, decreased reading time with 31%, t(16)= -2.20, p = .04, while scoring similar diagnostic performance compared to LE-RC, t(13.2) = -1.39, p - .20 or higher p-values. The reading process was more efficient on RC compared to LE. Diagnostic performance of CEM was superior to FFDM; F (2,26) = 16.1, p < .001. Average reading time did not differ between the three groups, F (2,25) = 3.15, p = .06. CONCLUSION: The reversed CEM hanging protocol (RC-LE) scored similar on diagnostic performance compared to LE-RC, while reading time was a third faster. Abnormalities were interpreted quicker on RC images. A RC-LE hanging protocol is therefore recommended for clinical practice and training. Diagnostic performance of CEM was (again) superior to FFDM.


Assuntos
Mama/diagnóstico por imagem , Mamografia/métodos , Radiologistas , Área Sob a Curva , Feminino , Humanos , Mamografia/instrumentação , Variações Dependentes do Observador , Curva ROC , Intensificação de Imagem Radiográfica/métodos , Padrões de Referência , Sensibilidade e Especificidade
17.
Eur J Radiol ; 117: 9-14, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31307658

RESUMO

OBJECTIVE: The purpose of this study was to investigate the impact of the new American College of Radiology (ACR) digital mammography (DM) phantom in evaluating phantom image quality (IQ) and average glandular dose (AGD) in a nationwide survey on DM systems. METHODS: On-site surveys of 239 DM units were conducted in 2017 and 2018, and comparisons were made between ACR screen-film mammography (SFM) phantom and DM phantom for accessing phantom IQ and AGD. The phantom IQ was assessed using the weighted phantom score, considering the size of each detail. RESULTS: When switching from SFM phantom to DM phantom, no significant difference was found in AGD (p = 0.06). The mean weighted phantom score was significantly higher for DM phantom than for SFM phantom in terms of fibers and specks, and so was the total weighted phantom score (DM phantom vs. SFM phantom: 8.61 ± 1.04 vs. 8.23 ± 0.77, p < 0.0001). The phantom IQ is thus more precise and can detect small differences when using DM phantom and investigating DM systems, especially for specks and fibers. However, the overall passing rate was lower for DM phantom (84.1%) than for SFM phantom (91.2%). This can be explained by the lower passing rate for mass (84.5%) with the DM phantom. CONCLUSION: The ACR DM phantom provides better discernment to assess specks and fibers in DM systems. This study may serve as a reference for implementing a DM quality control program and when conducting large-scale surveys with the new DM phantom in the digital era.


Assuntos
Mama/efeitos da radiação , Mamografia , Intensificação de Imagem Radiográfica , Feminino , Pesquisas sobre Serviços de Saúde , Humanos , Mamografia/instrumentação , Variações Dependentes do Observador , Imagens de Fantasmas , Doses de Radiação , Intensificação de Imagem Radiográfica/instrumentação , Intensificação de Imagem Radiográfica/métodos , Padrões de Referência , Taiwan
18.
Am Surg ; 85(6): 645-653, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31267907

RESUMO

The purpose of this meta-analysis was to determine the value of quantitative dynamic contrast-enhanced (DCE) MRI (DCE-MRI) in evaluating the response of breast cancer to neoadjuvant chemotherapy (NAC). PubMed, Embase, and Cochrane Library databases (from building to July 31, 2018) were searched to collect articles about the therapeutic evaluation of NAC using the quantitative DCE-MRI in patients with breast cancer. The sensitivities and specificities of quantitative DCE-MRI in the evaluation of NAC for breast cancer were extracted from the articles. Meta-DiSc1.4 was applied to evaluate the efficacy of the sensitivity and specificity; forest figure and summary receiver operating characteristics (SROC) were created. A total of 356 articles were enrolled in this study, including 739 cases in total, in which 218 cases were effective and the other 521 cases were ineffective to NAC, considering the pathological results as the gold standard. The sensitivity and specificity in the included 14 articles of quantitative DCE-MRI (Ktrans, Kep, and ve) in comprehensively evaluating NAC for breast cancer were 84 per cent (95% confidence interval (CI): 78-88%) and 83 per cent (95% CI: 79-86%), respectively. The area under SROC was 0.899 (95% CI: 0.867-0.943). The sensitivity and specificity in the three articles of Ktrans evaluating NAC for breast cancer were 84.1 per cent (95% CI: 71.0-92.1%) and 81.3 per cent (95% CI: 70.5%-88.5%), respectively. The area under SROC was 0.899 (95% CI: 0.834-0.962). Our study confirmed that the quantitative DCE-MRI is able to monitor NAC treatment for breast cancer because of its high sensitivity and specificity. However, there is a high degree of heterogeneity in published studies, highlighting the lack of standardization in the field.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/tratamento farmacológico , Meios de Contraste , Imagem por Ressonância Magnética/métodos , Terapia Neoadjuvante/métodos , Intensificação de Imagem Radiográfica/métodos , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Área Sob a Curva , Neoplasias da Mama/mortalidade , Estudos de Avaliação como Assunto , Medicina Baseada em Evidências , Feminino , Humanos , Pessoa de Meia-Idade , Curva ROC , Medição de Risco , Sensibilidade e Especificidade , Análise de Sobrevida , Resultado do Tratamento
20.
Opt Express ; 27(10): 14231-14245, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31163875

RESUMO

We present a pixel-specific, measurement-driven correction that effectively reduces errors in detector response that give rise to the ring artifacts commonly seen in X-ray computed tomography (CT) scans. This correction is easy to implement, suppresses CT artifacts significantly, and is effective enough for use with both absorption and phase contrast imaging. It can be used as a standalone correction or in conjunction with existing ring artifact removal algorithms to further improve image quality. We validate this method using two X-ray CT data sets acquired using monochromatic sources, showing post-correction signal-to-noise increases of up to 55%, and we define an image quality metric to use specifically for the assessment of ring artifact suppression.


Assuntos
Artefatos , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/instrumentação , Algoritmos
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