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1.
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
2.
Br J Radiol ; 93(1111): 20200055, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32462887

RESUMO

OBJECTIVE: To assess the accuracy and agreement of radiology information system (RIS) kerma-area product (KAP) data with respect to automatically populated dose management system (DMS) data for digital radiography (DR). METHODS: All adult radiographic examinations over 12 months were exported from the RIS and DMS at three centres. Examinations were matched by unique identifier fields, and grouped by examination type. Each centre's RIS sample completeness was calculated, as was the percentage of the RIS examination KAP values within 5% of their DMS counterparts (used as an accuracy metric). For each centre, the percentage agreement between the RIS and DMS examination median KAP values was computed using a Bland-Altman analysis. At two centres, up to 42.5% of the RIS KAP units entries were blank or invalid; corrections were attempted to improve data quality in these cases. RESULTS: Statistically significant intersite variation was seen in RIS data accuracy and the agreement between the uncorrected RIS and DMS median KAP data, with a Bland-Altman bias of up to 11.1% (with a -31.7% to 53.9% 95% confidence interval) at one centre. Attempts to correct invalid KAP units increased accuracy but produced worse agreement at one centre, a slight improvement at another and no significant change in the third. CONCLUSION: The RIS data poorly represented the DMS data. ADVANCES IN KNOWLEDGE: RIS KAP data are a poor surrogate for DMS data in DR. RIS data should only be used in patient dose surveys with an understanding of its limitations and potential inaccuracies.


Assuntos
Intensificação de Imagem Radiográfica/normas , Sistemas de Informação em Radiologia/normas , Adulto , Viés , Coleta de Dados/métodos , Coleta de Dados/normas , Humanos , Doses de Radiação , Proteção Radiológica/normas , Padrões de Referência , Sensibilidade e Especificidade
5.
Radiology ; 295(2): 390-396, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32125257

RESUMO

Background Spinal digital subtraction angiography (DSA) exposes patients and operators to substantial amounts of radiation. Antiscatter grid (ASG) removal is used to decrease radiation exposure but may reduce image quality. Purpose To determine whether ASG removal during spinal DSA in adults reduces radiation dose while maintaining diagnostic image quality and whether dose reduction is related to body mass index (BMI). Materials and Methods This Health Insurance Portability and Accountability Act-compliant prospective study included adults undergoing spinal DSA between January and December 2016. Each procedure included an additional angiographic acquisition performed twice, once with and once without ASG, either documenting the artery of Adamkiewicz (no pathology group) or the condition leading to the procedure (pathology group). Dose differences between study acquisitions and the influence of BMI were evaluated via paired t test. Two neurointerventionalists blinded to acquisition protocols were asked to independently evaluate a sample of 40 study acquisitions (20 with ASG, 20 without ASG) from 20 randomly selected participants to (a) rate image quality, (b) categorize findings, and (c) determine whether images had been obtained with or without ASG. Percentage agreement on image quality, findings categorization, and ability to correctly identify the acquisition protocol was calculated for both readers. Results Fifty-three participants (mean age ± standard deviation, 51 years ± 15.2; 32 men) were evaluated. ASG removal reduced the mean dose per acquisition by approximately 33% (mean dose-area product and air kerma decreased from 202 to 135.6 µGy/m2 and from 35.3 to 24 mGy, respectively; P < .001) independently of BMI (P = .3). Both readers evaluated all images (40 of 40) as being of diagnostic quality and correctly categorized findings in 19 of 20 (95%) cases. Overall percentage agreement for correct protocol identification was 60% (12 of 20) for grid-in and 45% (nine of 20) for grid-out images. Conclusion Antiscatter grid removal during spinal digital subtraction angiography decreased participants' radiation exposure while preserving diagnostic image quality. © RSNA, 2020.


Assuntos
Angiografia Digital/instrumentação , Proteção Radiológica/métodos , Intensificação de Imagem Radiográfica/instrumentação , Doenças da Coluna Vertebral/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Artefatos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Doses de Radiação , Exposição à Radiação , Espalhamento de Radiação
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
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
13.
Artigo em Japonês | MEDLINE | ID: mdl-32074529

RESUMO

The purpose of this study is to compare the detectability of diseases the new image processing and the conventional image processing by receiver operating characteristic (ROC) analysis and to show the usefulness of the new image processing. Radiographs with and without nodular cancer models in the chest phantom were used for observation samples. Totally 200 radiographs were evaluated by 10 radiological technologists (each readers had over 20 years or under 4 years of experience). The mean area under the curve (AUC) calculated from the over 20 years group was 0.754 for the new processing and 0.771 for the conventional processing (p value=0.651, 95% confidence interval=-0.084/0.049 (lower bound/upper bound)). On the other hand, the average AUC calculated from under 4 years group was 0.819 for the new processing and 0.678 for the conventional processing (p value= 0.041, 95% confidence interval=0.019/0.262 (lower bound/upper bound)). New image processing provides high detectability in less than 4 years group compared to conventional processing.


Assuntos
Imagens de Fantasmas , Intensificação de Imagem Radiográfica , Radiografia Torácica , Humanos , Curva ROC
14.
PLoS One ; 15(2): e0228376, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32023294

RESUMO

OBJECTIVES: The purpose of this study was to investigate the impact of a 150kV spectral filtration chest imaging protocol (Sn150kVp) combined with advanced modeled iterative reconstruction (ADMIRE) on radiation dose and image quality in patients after lung-transplantation. METHODS: This study included 102 patients who had unenhanced chest-CT examinations available on both, a second-generation dual-source CT (DSCT) using standard protocol (100kVp, filtered-back-projection) and, on a third-generation DSCT using Sn150kVp protocol with ADMIRE. Signal-to-noise-ratio (SNR) was measured in 6 standardized regions. A 5-point Likert scale was used to evaluate subjective image quality. Radiation metrics were compared. RESULTS: The mean time interval between the two acquisitions was 1.1±0.7 years. Mean-volume-CT-dose-index, dose-length-product and effective dose were significantly lower for Sn150kVp protocol (2.1±0.5mGy;72.6±16.9mGy*cm;1.3±0.3mSv) compared to 100kVp protocol (6.2±1.8mGy;203.6±55.6mGy*cm;3.7±1.0mSv) (p<0.001), equaling a 65% dose reduction. All studies were considered of diagnostic quality. SNR measured in lung tissue, air inside trachea, vertebral body and air outside the body was significantly higher in 100kVp protocol compared to Sn150kVp protocol (12.5±2.7vs.9.6±1.5;17.4±3.6vs.11.8±1.8;0.7±0.3vs.0.4±0.2;25.2±6.9vs.14.9±3.3;p<0.001). SNR measured in muscle tissue was significantly higher in Sn150kVp protocol (3.2±0.9vs.2.6±1.0;p<0.001). For SNR measured in descending aorta there was a trend towards higher values for Sn150kVp protocol (2.8±0.6 vs. 2.7±0.9;p = 0.3). Overall SNR was significantly higher in 100kVp protocol (5.0±4.0vs.4.0±4.0;p<0.001). On subjective analysis both protocols achieved a median Likert rating of 1 (25th-75th-percentile:1-1;p = 0.122). Interobserver agreement was good (intraclass correlation coefficient = 0.73). CONCLUSIONS: Combined use of 150kVp tin-filtered chest CT protocol with ADMIRE allows for significant dose reduction while maintaining highly diagnostic image quality in the follow up after lung transplantation when compared to a standard chest CT protocol using filtered back projection.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Pneumopatias/diagnóstico por imagem , Transplante de Pulmão/métodos , Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Radiografia Torácica/métodos , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Feminino , Humanos , Pneumopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Estudos Retrospectivos , Razão Sinal-Ruído , Estanho
17.
Sci Rep ; 10(1): 1225, 2020 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988331

RESUMO

The aim of this study was to investigate the feasibility of quantitative assessment of the therapeutic response in psoriatic arthritis (PsA) by measuring iodine uptake using a Dual-energy CT (DECT) iodine map. The study included 74 symptomatic and 74 matching non-symptomatic joints of 26 consecutive PsA patients who underwent two contrast enhanced DECTs of the hand or foot, pre and post medical interventions. Symptomatic and matched non-symptomatic control joints were scored with the PsA DECT Scoring System (PsADECTS), which was derived by modifying the PsA MRI Scoring System (PsAMRIS), a recently validated scoring system that assesses PsA changes on MRI. Quantified iodine uptake measured using the DECT iodine map was compared to the PsADECTS score. Efficacy of PsA treatment was confirmed by the improved clinical findings. Both PsADECTS and iodine uptake also showed significant improvement after treatment (Wilcoxon signed-rank test: z = 7.38, p < 0.005; z = 6.20, p < 0.005, respectively). The treatment effects of PsADECTS score and iodine uptake showed a good correlation with each other (Spearman's ρ = 0.58 p < 0.005). Inter-reader agreement for PsADECTS score and iodine uptake were either moderate or good. In conclusion, our study showed that the DECT iodine map is a valid tool for quantitative assessment of the therapeutic response of PsA.


Assuntos
Absorciometria de Fóton/métodos , Artrite Psoriásica/diagnóstico por imagem , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Artrite Psoriásica/terapia , Meios de Contraste , Estudos de Viabilidade , Feminino , Articulações dos Dedos/patologia , Articulações do Pé/patologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Iodo/metabolismo , Iodo/farmacologia , Masculino , Pessoa de Meia-Idade , Intensificação de Imagem Radiográfica/métodos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Índice de Gravidade de Doença , Resultado do Tratamento
18.
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
19.
J Comput Assist Tomogr ; 44(1): 70-74, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939885

RESUMO

PURPOSE: The aim of this study was to determine the valuable magnetic resonance imaging (MRI) features of sinonasal metastatic clear-cell renal cell carcinoma (cc-RCC), especially focusing on its dynamic-enhanced characteristics. METHODS: The conventional and dynamic-enhanced MRI findings of 8 patients with histopathologically confirmed sinonasal metastatic cc-RCC were reviewed by 2 radiologists. The control group of 8 patients with capillary hemangioma underwent the same MRI protocol. RESULTS: Metastatic cc-RCCs arose from the nasoethmoid region, maxillary sinus, posterior ethmoid and sphenoid sinus, and nasal cavity in 2 patients in each. These lesions were well circumscribed and the mean maximum dimension was 42 mm. The signal intensity of these lesions was isointense to brain stem on both MR T1- and T2-weighted images. All metastatic tumors showed vivid enhancement on enhanced T1-weighted image. Multiple flow voids within these metastatic lesions were identified in 6 patients. Peripheral cyst was detected around the metastatic tumor in 4 patients. Metastatic cc-RCCs exhibited a characteristic type 4 time intensity curve (TIC) similar to that of the internal carotid artery, whereas capillary hemangiomas showed a type 3 TIC on dynamic-enhanced MRI. CONCLUSIONS: A hypervascular mass with the characteristic type 4 TIC in the sinonasal region is highly suggestive of a metastatic cc-RCC.


Assuntos
Carcinoma de Células Renais/diagnóstico por imagem , Neoplasias Renais/diagnóstico por imagem , Cavidade Nasal/patologia , Neoplasias dos Seios Paranasais/diagnóstico por imagem , Neoplasias dos Seios Paranasais/secundário , Idoso , Carcinoma de Células Renais/patologia , Detecção Precoce de Câncer , Feminino , Humanos , Neoplasias Renais/patologia , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Cavidade Nasal/diagnóstico por imagem , Neoplasias dos Seios Paranasais/patologia , Período Pré-Operatório , Intensificação de Imagem Radiográfica
20.
J Comput Assist Tomogr ; 44(1): 78-82, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939886

RESUMO

OBJECTIVE: This study aimed to evaluate virtual monochromatic images (VMIs) obtained using dual-layer dual-energy computed tomography (CT) for breast carcinoma. METHODS: We retrospectively enrolled 28 patients with breast cancer who were pathologically diagnosed using dual-layer dual-energy CT. Virtual monochromatic images (40-200 keV) were generated. We compared CT number, image noise, contrast, and contrast-to-noise ratio (CNR) between VMIs with the highest CNR and conventional CT images. We performed qualitative image analysis between VMIs at optimized energy and conventional CT images. RESULTS: Image noise of VMIs was not significantly different from that of the conventional CT images. As the x-ray energy decreased, CNR increased. The 40-keV VMIs were highest CNR and higher than that of the conventional CT images. In qualitative image analysis, the 40-keV images were significantly higher than conventional CT images. CONCLUSION: Both qualitative and quantitative analyses showed that the image quality of VMIs at 40 keV was significantly higher than that of conventional CT images.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Intensificação de Imagem Radiográfica , Interpretação de Imagem Radiográfica Assistida por Computador , Estudos Retrospectivos , Razão Sinal-Ruído
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