Survey of computed tomography doses and establishment of national diagnostic reference levels in the Republic of Belarus.
Kharuzhyk S A,Matskevich S A,Filjustin A E,Bogushevich E V,Ugolkova S A
Radiation protection dosimetry
Computed tomography dose index (CTDI) was measured on eight CT scanners at seven public hospitals in the Republic of Belarus. The effective dose was calculated using normalised values of effective dose per dose-length product (DLP) over various body regions. Considerable variations of the dose values were observed. Mean effective doses amounted to 1.4 +/- 0.4 mSv for brain, 2.6 +/- 1.0 mSv for neck, 6.9 +/- 2.2 mSv for thorax, 7.0 +/- 2.3 mSv for abdomen and 8.8 +/- 3.2 mSv for pelvis. Diagnostic reference levels (DRLs) were proposed by calculating the third quartiles of dose value distributions (body region/volume CTDI, mGy/DLP, mGy cm): brain/60/730, neck/55/640, thorax/20/500, abdomen/25/600 and pelvis/25/490. It is evident that the protocols need to be optimised on some of the CT scanners, in view of the fact that these are the first formulated DRLs for the Republic of Belarus.
10.1093/rpd/ncq070
Peripheral quantitative computed tomography of the lower leg in children and adolescents: bone densities, cross-sectional sizes and muscle distribution reference data.
Jaworski Maciej,Kobylińska Maria,Graff Krzysztof
Journal of musculoskeletal & neuronal interactions
OBJECTIVES:Peripheral quantitative computed tomography is utilised in increasing numbers of paediatric studies, however, very little is known about the reference limits for pQCT tibia measurements. The purpose of this study was to establish country-specific reference data for bone densities, cross-sectional sizes, strength and regional muscle distribution measured by pQCT in children and adolescents. METHODS:Stratec XCT 2000L apparatus was used. The measurement sites were 4%, 14%, 38% and 66% of the tibia length. The study group consisted of 222 participants (103 girls) aged 4,3-19,4 yrs. ANCOVA was used to assess the main determinants of pQCT outcomes. The LMS method was used to fit the percentile curves for each outcomes. RESULTS:Weight and age were the main determinants for most of the pQCT outcomes. Smoothed percentile curves were developed by age and by height for both sexes. CONCLUSION:In this study we present reference data for bone densities, cross-sectional size and strength as well as for regional muscle distribution measured by pQCT at certain sites of the lower leg to allow simple calculation of reliable Z scores.
Age- and Sex-Specific Reference Values for Atrial and Ventricular Structures in the Validated Normal Chinese Population: A Comprehensive Measurement by Cardiac MRI.
Zhuang Baiyan,Li Shuang,Xu Jing,Zhou Di,Yin Gang,Zhao Shihua,Lu Minjie
Journal of magnetic resonance imaging : JMRI
BACKGROUND:Left and right cardiac structures have been shown to provide important prognostic information in patients with various cardiac disorders. They have always been important biomarkers in patients with heart failure and are crucial in the judgment of a variety of heart diseases. PURPOSE:To provide age- and sex-specific reference values of the normal cardiac structure of Chinese adults. STUDY TYPE:Prospective study. POPULATION:In all, 200 healthy adult volunteers with 20 men and 20 women in each of five age deciles from 20 to 70 years. FIELD STRENGTH:3.0T, steady-state free precession (SSFP), turbo spin-echo (TSE) sequence. ASSESSMENT:The reference range of cardiac structure values was normalized to age, gender, and body surface area (BSA). The height, weight, blood pressure, and body mass index were measured as well. STATISTIC TESTS:Kolmogorov-Smirnov's, independent-sample t-tests, one-way analysis of variance (ANOVA), Pearson's coefficient, and linear regression. RESULTS:The normalized left atrial (LA) transverse diameter (two-chamber view) at end-systolic, and left ventricular outflow tract diameter (LVOT) were significantly larger in females compared to males (all P < 0.001), while LA volume at end-systole was found higher in males (males: 36.25 ± 10.03 mL vs. females: 32.78 ± 10.27 mL). With increasing age, there was a weak but significant decrease in normalized LA transverse diameter (two-chamber view) at end- systolic (r = -0.25, P < 0.001). The normalized RA volume at end-systole and RVOT diameter showed significant decrease with advancing age (r = -0.22, P = 0.002; r = -0.34, P < 0.001). The indexed left and right ventricular volumes were mostly smaller with advancing age. The LA longitudinal parameters correlated significantly with LA area measured in the two-chamber view at end-systole (r = 0.78, P < 0.001). DATA CONCLUSION:Reference values for the morphological parameters of the intracardiac structure by sex and age distribution are provided in a Chinese population. LEVEL OF EVIDENCE:2 TECHNICAL EFFICACY: Stage 5 J. Magn. Reson. Imaging 2020;52:1031-1043.
10.1002/jmri.27160
Reference range determination for imaging biomarkers: Myocardial T.
Higgins David M,Keeble Claire,Juli Christoph,Dawson Dana K,Waterton John C
Journal of magnetic resonance imaging : JMRI
BACKGROUND:Imaging biomarkers, such as the T relaxation time of the myocardium using MRI, can be valuable in cardiac medicine if they are properly validated. Consensus statements recommend that for myocardial T , each investigator should establish a reference range. PURPOSE:To describe a statistically valid method for determining and reporting the reference range in each center, which simultaneously minimizes the twin risks of undersampling, leading to a uselessly uncertain range, and oversampling, which exposes volunteers to unnecessary scanning and wastes resources. STUDY TYPE:Cohort. POPULATION:In all, 278 normal human subjects without cardiac disease from two cardiac MR centers. FIELD STRENGTH/SEQUENCE:1.5 T and 3 T; Modified Look-Locker Inversion recovery sequence. ASSESSMENT:The T relaxation time was estimated from multiple samples of tissue magnetization after inversion. A valid method for calculating a reference range was used. STATISTICAL TESTS:Shapiro-Wilk test for normality; Tukey robust approach for identification of outliers; reference range calculation with confidence intervals. RESULTS:Reference ranges for measurement of myocardial T were calculated, with confidence intervals, enabling comparison with clinically important differences. At 3 T: 1129 to 1301 msec at site 1 (n = 21) and 1160 to 1309 msec at site 2 (n = 59), and at 1.5 T at site 2: 933 to 1020 msec (male, n = 130) and 965 to 1054 msec (female, n = 68). The 3 T reference range from site 1 was successfully benchmarked against the 3 T reference range at site 2. DATA CONCLUSION:Myocardial T reference ranges can be properly characterized, enabling clinical comparison to a valid reference range with known confidence intervals, using methodology similar to that described in this report. LEVEL OF EVIDENCE:3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:771-778.
10.1002/jmri.26683
Head-to-head comparison of left ventricular function assessment with 64-row computed tomography, biplane left cineventriculography, and both 2- and 3-dimensional transthoracic echocardiography: comparison with magnetic resonance imaging as the reference standard.
Greupner Johannes,Zimmermann Elke,Grohmann Andrea,Dübel Hans-Peter,Althoff Till F,Althoff Till,Borges Adrian C,Rutsch Wolfgang,Schlattmann Peter,Hamm Bernd,Dewey Marc
Journal of the American College of Cardiology
OBJECTIVES:This study was designed to compare the accuracy of 64-row contrast computed tomography (CT), invasive cineventriculography (CVG), 2-dimensional echocardiography (2D Echo), and 3-dimensional echocardiography (3D Echo) for left ventricular (LV) function assessment with magnetic resonance imaging (MRI). BACKGROUND:Cardiac function is an important determinant of therapy and is a major predictor for long-term survival in patients with coronary artery disease. A number of methods are available for assessment of function, but there are limited data on the comparison between these multiple methods in the same patients. METHODS:A total of 36 patients prospectively underwent 64-row CT, CVG, 2D Echo, 3D Echo, and MRI (as the reference standard). Global and regional LV wall motion and ejection fraction (EF) were measured. In addition, assessment of interobserver agreement was performed. RESULTS:For the global EF, Bland-Altman analysis showed significantly higher agreement between CT and MRI (p < 0.005, 95% confidence interval: ±14.2%) than for CVG (±20.2%) and 3D Echo (±21.2%). Only CVG (59.5 ± 13.9%, p = 0.03) significantly overestimated EF in comparison with MRI (55.6 ± 16.0%). CT showed significantly better agreement for stroke volume than 2D Echo, 3D Echo, and CVG. In comparison with MRI, CVG-but not CT-significantly overestimated the end-diastolic volume (p < 0.001), whereas 2D Echo and 3D Echo significantly underestimated the EDV (p < 0.05). There was no significant difference in diagnostic accuracy (range: 76% to 88%) for regional LV function assessment between the 4 methods when compared with MRI. Interobserver agreement for EF showed high intraclass correlation for 64-row CT, MRI, 2D Echo, and 3D Echo (intraclass correlation coefficient >0.8), whereas agreement was lower for CVG (intraclass correlation coefficient = 0.58). CONCLUSIONS:64-row CT may be more accurate than CVG, 2D Echo, and 3D Echo in comparison with MRI as the reference standard for assessment of global LV function.
10.1016/j.jacc.2012.01.046
Diagnostic Reference Levels based on clinical indications in computed tomography: a literature review.
Paulo Graciano,Damilakis John,Tsapaki Virginia,Schegerer Alexander A,Repussard Jacques,Jaschke Werner,Frija Guy,
Insights into imaging
BACKGROUND:In August 2017, the European Commission awarded the "European Study on Clinical Diagnostic Reference levels for X-ray Medical Imaging" project to the European Society of Radiology, to provide up-to-date Diagnostic Reference Levels based on clinical indications. The aim of this work was to conduct an extensive literature review by analysing the most recent studies published and the data provided by the National Competent Authorities, to understand the current situation regarding Diagnostic Reference Levels based on clinical indications for computed tomography. RESULTS:The literature review has identified 23 papers with Diagnostic Reference Levels based on clinical indications for computed tomography from 15 countries; 12 of them from Europe. A total of 28 clinical indications for 6 anatomical areas (head, cervical spine/neck, chest, abdomen, abdomen-pelvis, chest-abdomen-pelvis) have been identified. CONCLUSIONS:In all the six anatomical areas for which Diagnostic Reference Levels based on clinical indications were found, a huge variation of computed tomography dose descriptor values was identified, providing evidence for a need to develop strategies to standardise and optimise computed tomography protocols.
10.1186/s13244-020-00899-y