BACKGROUND. Dose reduction strategies for coronary CTA (CCTA) have been underused in clinical practice given concern that the strategies may lower image quality.OBJECTIVE. The purpose of this study... Show moreBACKGROUND. Dose reduction strategies for coronary CTA (CCTA) have been underused in clinical practice given concern that the strategies may lower image quality.OBJECTIVE. The purpose of this study was to explore associations between dose reduction strategies and CCTA image quality in real-world clinical practice.METHODS. This subanalysis of the international Prospective Multicenter Registry on Radiation Dose Estimates of Cardiac CT Angiography in Daily Practice in 2017 (PROTECTION VI) study included 3725 patients (2109 men, 1616 women; median age, 59 years) who underwent CCTA for coronary artery evaluation performed at 55 sites in 32 countries. CCTA image sets were reviewed at a core laboratory. A range of patient and scan characteristics, including use of three dose reduction strategies (prospective ECG triggering, low tube potential, and iterative image reconstruction) and image dose, were recorded. A single core laboratory member reviewed all examinations for quantitative image quality measures, including signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and reviewed 50% of examinations to assign a qualitative CCTA image quality score and a semiquantitative coronary calcification measure. Multivariable logistic regression models were used to identify predictors of image quality. A second core laboratory member repeated quantitative measures for 100 examinations and the qualitative measure for 383 (approximately 20%) examinations to assess interreader agreement.RESULTS. Independent predictors (p < .05) of SNR were female sex (effect size, 2.70), lower body mass index (0.38 per 1-unit decrease), stable sinus rhythm (1.71), and scanner manufacturer (variable effect across manufacturers). These factors were also the only independent predictors of CNR. Independent predictors (p < .05) of CCTA image quality were heart rate (0.17 per 10 beats/min reduction) and coronary calcification (0.15 per coronary calcification grade). None of the three dose-saving strategies or dose-length product was an independent predictor of any image quality measure. Interreader agreement analysis showed intraclass correlation coefficients of 0.874 for SNR and 0.891 for CNR and a kappa value of 0.812 for the qualitative score.CONCLUSION. This large international multicenter study shows that three dose reduction strategies were not associated with decreased CCTA image quality.CLINICAL IMPACT. The dose reduction strategies should be routinely implemented in clinical CCTA. Show less
OBJECTIVE. The purpose of this study is to assess CT-based markers predictive of the development of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism.MATERIALS... Show moreOBJECTIVE. The purpose of this study is to assess CT-based markers predictive of the development of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism.MATERIALS AND METHODS. Identified from a search of local registries, 48 patients ho had CTEPH develop were included in the study group, and 113 patients who had complete resolution of acute pulmonary embolism were included in the control group. Baseline CT scans obtained at the time of the initial pulmonary embolism event were evaluated for the degree of clot-induced vessel obstruction, the quantitative Walsh score, the ratio of the right ventricle diameter to the left ventricle diameter, the right atrium diameter, the pulmonary artery diameter, right heart thrombus, pericardial effusion, lung infarction, and mosaic attenuation. Classification and regression tree analysis was used to create a decision tree. The decision tree was externally validated on an anonymized cohort of 50 control subjects and 50 patients with CTEPH.RESULTS. During univariable analysis, an increase in the degree occlusive clot on initial imaging, a decrease in the Walsh score, absence of pericardial effusion, presence of lung infarction, and the presence of mosaic attenuation were associated with an increased probability of CTEPH development. In the final decision tree, the occlusive nature of the clot remained. Two patients in the cohort used for external validation had nondiagnostic findings and were excluded. The decision process correctly classified 33% (16/48) of patients who had CTEPH develop and 86% (43/50) of patients who did not have CTEPH develop, for an odds ratio of 3.1 (95% CI, 1.1-8.3).CONCLUSION. The presence of an occlusive clot on initial imaging is associated with an increased probability of CTEPH development. Presence of mosaic attenuation and lung infarction may also predict CTEPH development, although additional studies are needed. Show less
Tao, Q.; Lelieveldt, B.P.F.; Geest, R.J. van der 2020
OBJECTIVE. The recent advancement of deep learning techniques has profoundly impacted research on quantitative cardiac MRI analysis. The purpose of this article is to introduce the concept of deep... Show moreOBJECTIVE. The recent advancement of deep learning techniques has profoundly impacted research on quantitative cardiac MRI analysis. The purpose of this article is to introduce the concept of deep learning, review its current applications on quantitative cardiac MRI, and discuss its limitations and challenges.CONCLUSION. Deep learning has shown state-of-the-art performance on quantitative analysis of multiple cardiac MRI sequences and holds great promise for future use in clinical practice and scientific research. Show less
OBJECTIVE. Correcting the perfusion in areas distal to coronary stenosis (risk) according to that of normal (remote) areas defines the relative myocardial perfusion index, which is similar to the... Show moreOBJECTIVE. Correcting the perfusion in areas distal to coronary stenosis (risk) according to that of normal (remote) areas defines the relative myocardial perfusion index, which is similar to the fractional flow reserve (FFR) concept. The aim of this study was to assess the value of relative myocardial perfusion by MRI in predicting lesion-specific inducible ischemia as defined by FFR.MATERIALS AND METHODS. Forty-six patients (33 men and 13 women; mean [+/- SD] age, 61 +/- 9 years) who underwent adenosine perfusion MRI and FFR measurement distal to 49 coronary artery stenoses during coronary angiography were retrospectively evaluated. Subendocardial time-enhancement maximal upslopes, normalized by the respective left ventricle cavity upslopes, were obtained in risk and remote subendocardium during adenosine and rest MRI perfusion and were correlated to the FFR values.RESULTS. The mean FFR value was 0.84 +/- 0.09 (range, 0.60-0.98) and was less than or equal to 0.80 in 31% of stenoses (n = 15). The relative subendocardial perfusion index (risk-to-remote upslopes) during hyperemia showed better correlations with the FFR value (r = 0.59) than the uncorrected risk perfusion parameters (i.e., both the upslope during hyperemia and the perfusion reserve index [stress-to-rest upslopes]; r = 0.27 and 0.29, respectively). A cutoff value of 0.84 of the relative subendocardial perfusion index had an ROC AUC of 0.88 to predict stenosis at an FFR of less than or equal to 0.80.CONCLUSION. Using adenosine perfusion MRI, the relative myocardial perfusion index enabled the best prediction of FFR-defined lesion-specific myocardial ischemia. This index could be used to noninvasively determine the need for revascularization of known coronary stenoses. Show less
OBJECTIVE. The objective of this study was to assess the exposure of patients to radiation for the cardiac CT acquisition protocol of the multicenter Coronary Artery Evaluation Using 64-Row... Show moreOBJECTIVE. The objective of this study was to assess the exposure of patients to radiation for the cardiac CT acquisition protocol of the multicenter Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CORE 64) trial. MATERIALS AND METHODS. An algorithm for patient dose assessment with Monte Carlo dosimetry was developed for the Aquilion 64-MDCT scanner. During the CORE 64 study, different acquisition protocols were used depending on patient size and sex; therefore, six patient models were constructed representing three men and three women in the categories of small, normal size, and obese. Organ dose and effective dose resulting from the cardiac CT protocol were assessed for these six patient models. RESULTS. The average effective dose for coronary CT angiography (CTA) calculated according to Report 103 of the International Commission on Radiological Protection (ICRP) is 19 mSv (range, 16-26 mSv). The average effective dose for the whole cardiac CT protocol including CT scanograms, bolus tracking, and calcium scoring is slightly higher-22 mSv (range, 18-30 mSv). An average conversion factor for the calculation of effective dose from dose-length product of 0.030 mSv/mGy . cm was derived for coronary CTA. CONCLUSION. The current methods of assessing patient dose are not well suited for cardiac CT acquisitions, and published effective dose values tend to underestimate effective dose. The effective dose of cardiac CT is approximately 25% higher when assessed according to the preferred ICRP Report 103 compared with ICRP Report 60. Underestimation of effective dose by 43% or 53% occurs in coronary CTA according to ICRP Report 103 when a conversion factor (E/DLP, where E is effective dose and DLP is dose-length product) for general chest CT of 0.017 or 0.014 mSv/mGy . cm, respectively, is used instead of 0.030 mSv/mGy . cm. Show less
Elderen, S.G.C. van; Westenberg, J.J.M.; Brandts, A.; Meer, R.W. van der; Romijn, J.A.; Smit, J.W.A.; Roos, A. de 2011
OBJECTIVE. Arterial stiffness is an important predictor of cardiovascular disease in type 1 diabetes mellitus (DM). The purpose of this study was to investigate whether type 1 DM is associated with... Show moreOBJECTIVE. Arterial stiffness is an important predictor of cardiovascular disease in type 1 diabetes mellitus (DM). The purpose of this study was to investigate whether type 1 DM is associated with increased aortic stiffness as measured by MRI, independently of renal dysfunction, and to evaluate the relationship between aortic stiffness and renal function within the normal range in patients with type 1 DM. MATERIALS AND METHODS. We included 77 patients with type 1 DM (mean age, 46 +/- 12 years) and 36 healthy control subjects matched for age and renal function in a cross-sectional study. Exclusion criteria consisted of microalbuminuria, renal impairment, aortic valve disease, and standard MRI contraindications. Aortic pulse wave velocity (PWV), a marker of aortic stiffness, was assessed by MRI. Renal function was expressed as the estimated glomerular filtration rate (GFR). Mann-Whitney U test and Spearman's correlation analysis were performed. Stepwise multivariable logarithmic regressions with forward entry analysis for estimated GFR were performed to study the relationship with aortic PWV using interaction terms for type 1 DM. RESULTS. Patients with type 1 DM without microalbuminuria or renal impairment show increased aortic PWV compared with control subjects (p < 0.05). There was a statistically significant correlation between estimated GFR and aortic PWV in patients with type 1 DM (p < 0.001; r = -0.427) and control subjects (p = 0.002; r = -0.502), with aortic PWV being increased in patients with type 1 DM for each given estimated GFR within the normal range (p < 0.001). The decrease in estimated GFR per increase in aortic PWV was similar for patients with type 1 DM and control subjects (p, not significant). CONCLUSION. Our data show that aortic stiffness, as measured by MRI, is increased and inversely related to renal function in patients with type 1 DM with normal albuminuria and normal estimated GFR. Show less
Bijl, N. van der; Joemai, R.M.S.; Geleijns, J.; Bax, J.J.; Schuijf, J.D.; Roos, A. de; Kroft, L.J.M. 2010
OBJECTIVE. The purpose of this article is to evaluate to what extent Agatston scores may be derived from CT coronary angiography (CTA) examinations, compared with traditional unenhanced CT calcium... Show moreOBJECTIVE. The purpose of this article is to evaluate to what extent Agatston scores may be derived from CT coronary angiography (CTA) examinations, compared with traditional unenhanced CT calcium scores. MATERIALS AND METHODS. Fifty patients with a CT calcium score-Agatston score of zero and 50 patients with a CT calcium score-Agatston score of 1 or greater whose CT calcium scores had been calculated and who had undergone CTA using volumetric 320-MDCT were included. Agatston scores were obtained at 3.0-mm slices for CT calcium score and CTA. Method agreement, interobserver agreement, and diagnostic performance of CTA for detecting coronary calcium were evaluated. RESULTS. Of 50 patients with a positive CT calcium score-Agatston score, coronary artery calcium was detected with CTA in 43 patients by observer 1 (mean CTA score, 102 +/- 202; mean CT calcium score, 254 +/- 501) and in 46 patients by observer 2 (mean CTA score, 94 +/- 147; mean CT calcium score, 272 +/- 531). Of the 50 patients with a CT calcium score-Agatston score of zero, 49 (98%, observer 1) and 50 (100%, observer 2) had a zero score with CTA as well. An intraclass correlation of 0.78 and 0.62 was found between CT calcium score and CTA (p < 0.01), whereas higher Agatston scores were underestimated with CTA. For observer 1, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for detection of coronary calcium with CTA were 86%, 98%, 98%, 88%, and 92%, respectively, and the corresponding values for observer 2 were 92%, 100%, 100%, 93%, and 96%, respectively. Interobserver agreement was 0.996 for CT calcium score and 0.93 for CTA. CONCLUSION. Coronary artery calcium can be detected on CTA images with high accuracy. The Agatston calcium score derived from CTA images shows good correlation with unenhanced CT calcium score and is highly reproducible. However, higher Agatston scores are systematically underestimated when derived from CTA images. Show less
Dogan, H.; Kroft, L.J.M.; Huisman, M.V.; Geest, R. van der; Li, Y.; Lamb, H.J.; Roos, A. de 2010
OBJECTIVE. The purpose of this article is to determine the independent predictors of right ventricular (RV) dysfunction in patients with acute pulmonary embolism (PE) and to assess the relationship... Show moreOBJECTIVE. The purpose of this article is to determine the independent predictors of right ventricular (RV) dysfunction in patients with acute pulmonary embolism (PE) and to assess the relationship between RV ejection fraction (EF) and PE load. SUBJECTS AND METHODS. Breath-hold CT of the chest was performed for 64 patients with PE (33 men and 31 women; mean [+/- SD] age, 58.6 +/- 16.5 years). In addition, ECG-synchronized cardiac CT was performed to determine the RV and left ventricular (LV) EFs. PE load was determined using the Qanadli obstruction index. Multivariable regression analysis was performed to determine independent predictors of RV dysfunction (defined as EF < 35%). In addition, the relationship between RV EF and PE load was assessed by receiver operating characteristic (ROC) curves. RESULTS. RV dysfunction was independently predicted by a PE load greater than 50% (odds ratio, 40.17; 95% CI, 4.22-382.67) and an LV EF less than 45% (odds ratio, 31.18; 95% CI, 2.00-487.09; p < 0.05 for both). Curve analysis revealed that a PE load greater than 50% had a sensitivity of 82% and a specificity of 85% to identify an RV EF less than 35%. Conversely, an RV EF less than 35% had a sensitivity of 93% and a specificity of 67% to predict a PE load greater than 50%. CONCLUSION. RV dysfunction (defined as RV EF < 35%) in patients with acute PE is highly sensitive to define a PE load greater than 50%. Furthermore, RV dysfunction is independently predicted by an obstruction index greater than 50% or an LV EF less than 45%. Assessment of RV function by ECG-synchronized CT may become useful for guiding therapy. Show less
Molen, A. van der; Otero-Garcia, M.; Salvador-Izquierdo, R. 2010
