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1.
Artículo en Japonés | MEDLINE | ID: mdl-33883366

RESUMEN

PURPOSE: Using a pediatric head phantom constructed in our department, we examined a method to reduce exposure by using organ-effective modulation (OEM; Toshiba Medical Systems Corporation, Tochigi) to tilt the gantry during pediatric head computed tomography (CT) scanning. METHOD: The radiation reduction and CT image standard deviation (SD) were measured at gantry angles at which the orbit was slightly irradiated, partially irradiated, and completely irradiated. The OEM incident surface dose reduction rate was measured using an automatic exposure control (AEC) phantom with a diameter of 6-18 cm. RESULTS: The lens surface dose reduction rate using OEM was 21.2%. When the gantry was tilted and the orbit was completely out of the scanning range, the rate of reduction was 47.8%. OEM incident surface dose reduction rates were 27.4% for a phantom diameter of 18 cm, 22.0% for that of 16 cm, 17.8% for that of 14 cm, 17.2% for that of 12 cm, 8.4% for that of 10 cm, and 0% for that of 8 cm and 6 cm. OEM effectiveness decreased with decreasing phantom diameter. The use of OEM increased the rate of change of SD by 1.25´ when the gantry inclination was 0°, 1.27´ when the gantry inclination was 10°, and 1.27´ when the gantry inclination was 20°in the 12 o'clock position. CONCLUSION: The degree of reduction in exposure dose to the lens in pediatric head CT imaging was 47.8% by completely removing the lens from the irradiation range using gantry tilt and 21.2% by using OEM. The effect of OEM changed in proportion to tube current. The exposure reduction effect of the OEM decreases with decreasing head size, indicating its reduced effectiveness in head CT scans of smaller infants.


Asunto(s)
Cristalino , Tomografía Computarizada por Rayos X , Niño , Cabeza/diagnóstico por imagen , Humanos , Lactante , Fantasmas de Imagen , Dosis de Radiación
2.
Artículo en Japonés | MEDLINE | ID: mdl-33883367

RESUMEN

OBJECTIVES: Optimal beam quality for detection of pulmonary nodules in digital chest radiography using CsI-flat panel detector (FPD) was investigated in consideration of image quality and patient dose. METHODS: The human chest phantom with inserted imitated nodules (diameter: 10 mm, CT value: +30 Hounsfield unit (HU), -375 HU, -620 HU) was used for the measurement of contrast-to-noise ratio (CNR) of imitated nodules by twenty beams arranged by five tube voltages and four filters. RESULTS: The CNR varies with X-ray tube voltage and added filter. CNR correlates weakly to the tube voltage, fairly to the effective energy in second-order polynomial and strongly to the quality index (effective energy divided X-ray tube voltage). In order to improve the CNR, the effective energy and the quality index are kept about 50 keV and more than 0.5, respectively, using an 80-100 kV beam with a copper filter. CONCLUSION: A 90 kV (2.5 mm Al inherent filtration) beam with a 0.15 mm copper filter and a 90 kV or 100 kV (2.5 mm Al inherent filtration) beam with a 0.2 mm copper filter are appropriate for chest radiography using CsI-FPD.


Asunto(s)
Algoritmos , Intensificación de Imagen Radiográfica , Humanos , Fantasmas de Imagen , Dosis de Radiación , Radiografía , Radiografía Torácica
3.
Artículo en Japonés | MEDLINE | ID: mdl-33883370

RESUMEN

PURPOSE: In 2011, the International Commissionon Radiological Protection (ICRP) recommended reducing the threshold dose for the lens. Therefore, it is important to reduce the lens exposure dose in medical exposures. In a cranio-caudal (CC) view of mammography, the patient' s lens receives scattered radiation. In this study, we investigated scatter dose around the lens during mammography and reviewed the simple and easy protection methods of the lens. METHODS: Optically stimulated luminescence (OSL) dosimeters were placed in front of the device to obtain scattered radiation intensity distribution. The human phantom was placed in the same way as the CC positioning, and BR-12 phantoms with a thickness of 40 mm was placed on the FPD. Then, the scatter dose around the lens was measured using an OSL dosimeter. In order to confirm the change in the scatter radiation dose by the face guard (FG) and eyelid, we measured and compared under the same conditions the presence of FG and adipose tissue about 1 mm thick assuming the eyelid. RESULTS: Scatter radiation intensity decreased around the FG. When the FG was installed, the scatter dose was reduced about 33%, and when the adipose tissue was pasted on the OSL dosimeter, the scatter dose was reduced about 29%. CONCLUSION: This study suggested that eye closure during mammography was effective in reducing lens exposure. In the future, we would like to expect further protective effects by increasing the thickness of FG and reviewing the materials.


Asunto(s)
Cristalino , Protección Radiológica , Párpados , Humanos , Mamografía , Dosis de Radiación
5.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 52(2): 286-292, 2021 Mar.
Artículo en Chino | MEDLINE | ID: mdl-33829704

RESUMEN

Objective: To evaluate the noise reduction effect of deep learning-based reconstruction algorithms in thin-section chest CT images by analyzing images reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and deep learning image reconstruction (DLIR) algorithms. Methods: The chest CT scan raw data of 47 patients were included in this study. Images of 0.625 mm were reconstructed using six reconstruction methods, including FBP, ASIR hybrid reconstruction (ASIR50%, ASIR70%), and deep learning low, medium and high modes (DL-L, DL-M, and DL-H). After the regions of interest were outlined in the aorta, skeletal muscle and lung tissue of each group of images, the CT values, SD values and signal-to-noise ratio (SNR) of the regions of interest were measured, and two radiologists evaluated the image quality. Results: CT values, SD values and SNR of the images obtained by the six reconstruction methods showed statistically significant difference ( P<0.001). There were statistically significant differences in the image quality scores of the six reconstruction methods ( P<0.001). Images reconstruced with DL-H have the lowest noise and the highest overall quality score. Conclusion: The model based on deep learning can effectively reduce the noise of thin-section chest CT images and improve the image quality. Among the three deep-learning models, DL-H showed the best noise reduction effect.


Asunto(s)
Aprendizaje Profundo , Algoritmos , Humanos , Procesamiento de Imagen Asistido por Computador , Dosis de Radiación , Interpretación de Imagen Radiográfica Asistida por Computador , Tomografía Computarizada por Rayos X
6.
Br J Radiol ; 94(1121): 20210013, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33861140

RESUMEN

OBJECTIVES: Studies show insufficient sensitivity of virtual non-contrast (VNC) reconstructions for stone detection in dual-energy CT urography (DE-CTU). The aim of this study was to investigate if side-by-side-evaluation of both VNC and post-contrast images could increase the sensitivity of single-phase split bolus DE-CTU. METHODS: Consecutive patients with haematuria who underwent split bolus DE-CTU on the same dual-source DE-CT scanner were retrospectively enrolled in the study. Intravenous furosemide and oral hydration were employed. Two readers, independently and then jointly in two separate sessions, recorded the location and the longest axial stone diameter on three randomised sets of images: separate VNC and post-contrast images, and side-by-side-reconstructions. True non-contrast (TNC) images served as the standard of reference. RESULTS: A total of 83 urinary stones were detected on TNC images. Independent reader side-by-side-evaluation of VNC and post-contrast images yielded higher stone detection sensitivity (76 and 84%, respectively) compared to evaluation of only VNC (71 and 81%, respectively) or post-contrast images (64 and 80%, respectively). The sensitivity of joint reader evaluation of side-by-side-images reached almost 86% and was not significantly different from TNC images (p = 0.77). All stones larger than 3 mm were correctly detected by side-by-side-evaluation. Dose reduction of 55% could be achieved by omitting TNC scans. CONCLUSION: Side-by-side-VNC and post-contrast image evaluation enable detection of clinically significant urolithiasis on single-phase split bolus DE-CTU with significant dose reduction. ADVANCES IN KNOWLEDGE: This study shows that single-phase DE-CTU is feasible if VNC imaging is simultaneously utilised with post-contrast images.


Asunto(s)
Medios de Contraste , Tomografía Computarizada por Rayos X/métodos , Urografía/métodos , Urolitiasis/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Hematuria/etiología , Humanos , Cálculos Renales/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Dosis de Radiación , Estudios Retrospectivos , Sensibilidad y Especificidad , Cálculos Ureterales/diagnóstico por imagen , Cálculos de la Vejiga Urinaria/diagnóstico por imagen , Urolitiasis/complicaciones
9.
Mutat Res ; 863-864: 503312, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33678244

RESUMEN

Most blood components for transfusions are irradiated ex vivo to prevent transfusion-associated graft-versus-host disease (TA-GvHD); this irradiation can potentially affect the cytogenetic dose assessment of patients showing acute radiation syndrome (ARS) with bone marrow suppression or acute anaemia. Whole blood samples from five donors were irradiated with 0, 10 or 25 Gy γ-rays. The mitotic activity of each cultured blood sample was measured by calculating the mitotic index. A dicentric chromosome assay was used to evaluate the chromosomal aberrations and absorbed dose of blood lymphocytes. Mitogenic activity and scorable metaphase spreads were significantly decreased in the blood samples irradiated with 10 and 25 Gy (p < 0.001). Moreover, a significant increase in the mean scores of all types of chromosomal aberrations in the 10 Gy γ-irradiated samples was observed, with the estimated dose being 11.3 Gy (95% CI: 10.67-11.95 Gy); however, we were unable to estimate the exposure dose in the 25 Gy γ-irradiated samples due to a limited number of scorable metaphase spreads. The mitotic index of the 25 Gy γ-irradiated whole blood samples was significantly suppressed by more than 4-log fold. Thus, in the present study, we evaluated the effects of recommended radiation doses in γ-irradiated transplantation blood components using cytogenetic dosimetry. These results suggest that the partial transfusion of blood components to patients with ARS or acute anaemia did not compromise the estimation of the exposure dose using cytogenetic dosimetry.


Asunto(s)
Aberraciones Cromosómicas/efectos de la radiación , Rayos gamma/efectos adversos , Linfocitos/metabolismo , Adulto , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Linfocitos/patología , Masculino , Dosis de Radiación
10.
Br J Radiol ; 94(1120): 20200974, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33684310

RESUMEN

OBJECTIVE: To evaluate the value of using low energy (keV) images in renal dual-energy spectral CT angiography (CTA) and adaptive statistical iterative reconstruction (ASIR) to reduce contrast medium dose. METHODS: 40 patients with renal CTA on a Discovery CT750HD were randomly divided into two groups: 20 cases (Group A) with 600 mgI kg-1 and 20 cases (Group B) with 300 mgI kg-1. The scan protocol for both groups was: dual-energy mode with mA selection for noise index of 10 HU, pitch 1.375:1, rotating speed 0.6 s/r. Images were reconstructed at 0.625 mm thickness with 40%ASIR, Group A used the conventional 70keV monochromatic images, and Group B used monochromatic images from 40 to 70 keV at 5 keV interval for analysis. The CT values and standard deviation (SD) values of the renal artery and erector spine in the plain and arterial phases were measured with the erector spine SD value representing image noise. The enhancement degree of the renal artery (ΔCT = CT(arterial) -CT(plain)), signal-to-noise ratio (SNR=CTrenal-artery/SDrenal-artery) and contrast-to-noise ratio (CNR=(CTrenal-artery-CTerector spine)/SDerector-spine) were calculated. The single factor analysis of variance was used to analyze the difference of ΔCT, SNR and CNR among image groups with p < 0.05 being statistically significant. The subjective image scores of the groups were assessed blindly by two experienced physicians using a 5-point system and the score consistency was compared by the κ test. RESULTS: Contrast medium dose in the 300 mgI kg-1 group was reduced by 50% compared with the 600 mgI kg-1 group, while radiation dose was similar between the two groups. The subjective scores were 4.00 ± 0.65, 4.50 ± 0.60 and 3.70 ± 0.80 for images at 70 keV (600 mgI kg-1 group), 40 keV (300 mgI kg-1 group) and 45 keV (300 mgI kg-1 group), respectively with good consistency between the two reviewers (p > 0.05). The 40 keV images in the 300 mgI kg-1 group had similar ΔCT (469.77 ± 86.95 HU vs 398.54 ± 73.68 HU) and CNR (15.52 ± 3.32 vs 18.78 ± 6.71) values as the 70 keV images in the 600 mgI kg-1) group but higher SNR values (30.19 ± 4.41 vs 16.91 ± 11.12, p < 0,05). CONCLUSION: Contrast dose may be reduced by 50% while maintaining image quality by using lower energy images combined with ASIR in renal dual-energy CTA. ADVANCES IN KNOWLEDGE: Combined with ASIR and energy spectrum, can reduce the amount of contrast dose in renal CTA.


Asunto(s)
Angiografía por Tomografía Computarizada/métodos , Medios de Contraste/administración & dosificación , Intensificación de Imagen Radiográfica/métodos , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Arteria Renal/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Riñón/irrigación sanguínea , Riñón/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Dosis de Radiación , Imagen Radiográfica por Emisión de Doble Fotón/métodos , Relación Señal-Ruido , Adulto Joven
11.
Eur J Radiol ; 138: 109607, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33667936

RESUMEN

OBJECTIVE: To investigate the impact of X-ray preset acquisition protocol settings on fluoroscopy image quality (IQ) and radiation exposure. MATERIALS & METHODS: A quality control (QC) phantom was imaged with a modern digital C-arm system, using various preset fluoroscopy protocols. IQ was assessed using human observers and in-house software for automated evaluation, based on contrast-to-noise ratios of details and their background. Patient radiation exposure was evaluated using the displayed Incident Air-Kerma and Kerma-Area Product values. RESULTS: Protocol selection affects radiation exposure by a factor of about 3. IQ evaluation showed that acquisition protocols produce images with quite different characteristics. The visual IQ evaluation method was time consuming and cumbersome. The automated method, utilized the visual IQ evaluation results for calibration of detection thresholds. However, it failed to reproduce these results for all images and details types. In some images, digital image processing created artifacts which affected the pixel value distributions around details in a way that could be handled only by the human vision. CONCLUSION: Manufacturers provide many preset protocols designated for specific clinical uses, which have large impact on IQ characteristics and radiation exposure. However, protocol settings' selection rationale is essentially a "black box" for the end user. Though QC phantoms are currently used for IQ evaluation, they are not appropriate for drawing firm conclusions concerning the expected performance of each protocol in clinical practice. Currently, there is no consensus on the optimum technical characteristics of preset protocols for specific procedures. More work is needed in this area.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Exposición a la Radiación , Fluoroscopía , Humanos , Fantasmas de Imagen , Dosis de Radiación
12.
Eur J Radiol ; 138: 109646, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33721769

RESUMEN

PURPOSE: Phantom studies in CT emphysema quantification show that iterative reconstruction and deep learning-based noise reduction (DLNR) allow lower radiation dose. We compared emphysema quantification on ultra-low-dose CT (ULDCT) with and without noise reduction, to standard-dose CT (SDCT) in chronic obstructive pulmonary disease (COPD). METHOD: Forty-nine COPD patients underwent ULDCT (third generation dual-source CT; 70ref-mAs, Sn-filter 100kVp; median CTDIvol 0.38 mGy) and SDCT (64-multidetector CT; 40mAs, 120kVp; CTDIvol 3.04 mGy). Scans were reconstructed with filtered backprojection (FBP) and soft kernel. For ULDCT, we also applied advanced modelled iterative reconstruction (ADMIRE), levels 1/3/5, and DLNR, levels 1/3/5/9. Emphysema was quantified as Low Attenuation Value percentage (LAV%, ≤-950HU). ULDCT measures were compared to SDCT as reference standard. RESULTS: For ULDCT, the median radiation dose was 84 % lower than for SDCT. Median extent of emphysema was 18.6 % for ULD-FBP and 15.4 % for SDCT (inter-quartile range: 11.8-28.4 % and 9.2 %-28.7 %, p = 0.002). Compared to SDCT, the range in limits of agreement of emphysema quantification as measure of variability was 14.4 for ULD-FBP, 11.0-13.1 for ULD-ADMIRE levels and 10.1-13.9 for ULD-DLNR levels. Optimal settings were ADMIRE 3 and DLNR 3, reducing variability of emphysema quantification by 24 % and 27 %, at slight underestimation of emphysema extent (-1.5 % and -2.9 %, respectively). CONCLUSIONS: Ultra-low-dose CT in COPD patients allows dose reduction by 84 %. State-of-the-art noise reduction methods in ULDCT resulted in slight underestimation of emphysema compared to SDCT. Noise reduction methods (especially ADMIRE 3 and DLNR 3) reduced variability of emphysema quantification in ULDCT by up to 27 % compared to FBP.


Asunto(s)
Enfisema , Enfisema Pulmonar , Humanos , Enfisema Pulmonar/diagnóstico por imagen , Dosis de Radiación , Interpretación de Imagen Radiográfica Asistida por Computador , Estándares de Referencia
13.
Ann Hematol ; 100(5): 1241-1249, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33660034

RESUMEN

The objective of this study is to evaluate the prognostic features of multiple myeloma (MM) using whole-body low-dose computed tomography (WBLDCT). One hundred three patients with biopsy-proven MM who underwent WBLDCT were retrospectively enrolled. The evolution of osteolytic lesions overtime was performed by measuring the maximum axial diameter at the baseline (T0) and the end of follow-up (Te), by using a cut-off value of 10 mm. The location and dimension of up to three lesions were registered. The time-to-fracture (TTF) was recorded. Sixty-three percent of patients presented a focal pattern, 22% a diffuse pattern, and 15% a combined one. Seventy-two percent of patients with lesions ≤ 10 mm presented stability, 27% a dimensional increase, and 1% a decrease. Patients with lesions >10 mm showed a statistically significant difference regarding the mean difference of axial diameter between T0 and Te (p = 0.015). Patients with lesions >10 mm showed an odds ratio (OR) of 29.8 (95%CIs 3.8-230.5) to develop at least one fracture. Mean TTF was significantly lower in patients with lesions >10 mm in comparison with lesions ≤ 10 mm (9 ± 3 vs 23 ± 7 months, respectively, p = 0.011). WBLDCT represents a reliable imaging-based tool for proper management of MM patients, showing that diffuse form or small lytic lesions may deserve a less frequent follow-up.


Asunto(s)
Mieloma Múltiple/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mieloma Múltiple/patología , Estadificación de Neoplasias/métodos , Dosis de Radiación , Estudios Retrospectivos , Tomografía Computarizada por Rayos X/métodos , Imagen de Cuerpo Entero/métodos
14.
Artículo en Japonés | MEDLINE | ID: mdl-33746173

RESUMEN

PURPOSE: To evaluate image quality for chest radiography at different radiation qualities, using phantoms with scatter fractions similar to those of lungs. METHODS: Two base phantoms with 10 and 4 cm thicknesses, respectively, made of a soft tissue-equivalent material, were used to mimic the X-ray attenuation of the human lung. Two plates with soft tissue- and bone-equivalent materials, respectively, were placed on the base phantom as contrast objects. The image data were obtained with the same entrance surface dose in each radiation quality. Six radiation qualities generated using 120 and 90 kV, and additional copper filters with thicknesses 0, 0.1, and 0.2 mm were selected. The signal-difference-to-noise ratio (SdNR) and a contrast ratio of the soft tissue to the bone were measured for the six radiation qualities. RESULTS: The thicker the additional filter, the better the SdNR at both tube voltages. The SdNR values were not significantly different between 120 and 90 kV for the same filter thickness. The contrast ratio was higher at 120 than at 90 kV by approximately 8%. CONCLUSIONS: Because of the advantage of the contrast ratio and the highest SdNR, the radiation quality with 120 kV and 0.2-mm copper filtration was the best. It was indicated that the conventional tube voltage of 120 kV remains to be better than the lower tube voltage of 90 kV.


Asunto(s)
Intensificación de Imagen Radiográfica , Tórax , Humanos , Fantasmas de Imagen , Dosis de Radiación , Relación Señal-Ruido , Rayos X
15.
Artículo en Japonés | MEDLINE | ID: mdl-33746175

RESUMEN

OBJECTIVE: In cerebral angiography, the patient's exposure dose varies greatly depending on the target site, purpose, and difficulty of the procedure. Therefore, it is necessary to manage the dose based on not only the disease but also the procedure. METHODS: In this study, diagnostic cerebral angiography (diagnosis group) was classified into 13 procedures and neuro-interventional radiology (treatment group) was classified into 10 procedures, and the total dose, fluoroscopy dose, radiographic dose, fluoroscopy time, and number of radiographic frames were compared. RESULTS: For each item, the treatment group was significantly higher than the diagnosis group, but for some, the diagnosis group exceeded the median of treatment group. For the diagnosis group, the total irradiation time and fluoroscopy time were significant, and for the treatment group, all the items showed significant differences due to differences in procedures, and there were also cases where the same disease had differences due to procedures. CONCLUSION: To manage patient exposure in cerebral angiography, it is necessary to manage the usage rate and dose of fluoroscopy and radiography. In addition, it is important to evaluate, manage, and optimize the total dose, fluoroscopic dose, and radiographic dose for each procedure in not only the treatment group but also the diagnosis group.


Asunto(s)
Radiografía Intervencional , Radiología Intervencional , Angiografía Cerebral , Fluoroscopía , Humanos , Dosis de Radiación
16.
Artículo en Japonés | MEDLINE | ID: mdl-33746176

RESUMEN

PURPOSE: A volume scan can cover a range of 160 mm with a single gantry rotation. It can be performed sequentially (a wide volume [WV] scan) to cover more than 160 mm, and volume Xact+ (Xact+) can be used when volume scan is done to extend the reconstruction area. The purpose of this study was to investigate the dose distribution and organ doses for a WV scan during chest CT. METHOD: We arranged radiophotoluminescence glass dosimeters (RPLDs) linearly on the surface and inside of the phantom to evaluate the dose distribution along the z-axis. We also placed RPLDs at the lens, thyroid, and breast positions to evaluate organ doses. We performed WV and helical scans and WV scan using Xact+. RESULT: The absorbed doses increased at the borders of the volume scans, and dose peaks were observed there. The organ doses for the WV scan outside the acquisition range were lower than those for the helical scan. The organ doses inside the acquisition range changed by the locations of borders. CONCLUSION: The WV scan increases the absorbed doses at the overlapping scanned regions, which can be reduced by using Xact+.


Asunto(s)
Tórax , Tomografía Computarizada por Rayos X , Fantasmas de Imagen , Dosis de Radiación , Dosímetros de Radiación
20.
Arq Bras Cardiol ; 116(1): 100-105, 2021 01.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-33566972

RESUMEN

BACKGROUND: Image quality and radiation dose are optimized with a slow, steady heart rate (HR) when imaging the coronary arteries during cardiac computed tomography angiography (CCTA). The safety, efficacy, and protocol for HR reduction with beta blocker medication is not well described in a pediatric patient population. OBJECTIVE: Provide a safe and efficient metoprolol dose protocol to be used in pediatric outpatients undergoing CCTA. METHODS: We conducted a retrospective review of all pediatric outpatients who received metoprolol during CCTA. Demographic and clinical characteristics were summarized and the average reduction in HR was estimated using a multivariate linear regression model. Images were evaluated on a 1-4 scale (1= optimal). RESULTS: Seventy-eight pediatric outpatients underwent a CCTA scan with the use of metoprolol. The median age was 13 years, median weight of 46 kg, and 36 (46%) were male. The median doses of metoprolol were 1.5 (IQR 1.1, 1.8) mg/kg and 0.4 (IQR 0.2, 0.7) mg/kg for oral and intravenous administrations, respectively. Procedural dose-length product was 57 (IQR 30, 119) mGy*cm. The average reduction in HR was 19 (IQR 12, 26) beats per minute, or 23%. No complications or adverse events were reported. CONCLUSION: Use of metoprolol in a pediatric outpatient setting for HR reduction prior to CCTA is safe and effective. A metoprolol dose protocol can be reproduced when a slower HR is needed, ensuring faster acquisition times, clear images, and associated reduction in radiation exposure in this population. (Arq Bras Cardiol. 2021; 116(1):100-105).


Asunto(s)
Enfermedad de la Arteria Coronaria , Metoprolol , Adolescente , Niño , Angiografía por Tomografía Computarizada , Angiografía Coronaria , Frecuencia Cardíaca , Humanos , Masculino , Metoprolol/efectos adversos , Pacientes Ambulatorios , Dosis de Radiación , Estudios Retrospectivos
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