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Find video protocols related to scientific articles indexed in Pubmed.
Effects of renal denervation on end organ damage in hypertensive patients.
Eur J Prev Cardiol
PUBLISHED: 10-19-2014
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Renal denervation (RDN) is believed to reduce sympathetic nerve activity and is a potential treatment for resistant hypertension. The present study investigated the effects of RDN on end organ damage (EOD).
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Transcatheter Aortic Valve Replacement: Postoperative CT Findings of Sapien and CoreValve Transcatheter Heart Valves.
Radiographics
PUBLISHED: 10-14-2014
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Transcatheter aortic valve replacement represents one of the most exciting medical technical developments in recent years, offering a much-needed therapeutic alternative for patients with severe aortic valve stenosis who, due to comorbidities and advanced age, are considered to be inoperable or at high surgical risk. The efficacy of this procedure compared with standard surgical intervention has been properly validated in multicenter randomized controlled trials (PARTNER A and B trials), leading to widespread clinical implementation, with over 50,000 procedures currently being performed worldwide each year. Although much of the attention has rightly focused on the potential role of computed tomography (CT) in the preprocedural assessment of the aortic root and the establishment of imaging-guided valve-sizing algorithms, less is known regarding the postprocedural CT characteristics of transcatheter heart valves (THVs). However, given the increasing worldwide recognition and clinical implementation of these devices, they will no doubt be encountered with increasing frequency in patients referred for thoracic CT, either for postprocedural evaluation of the aortic root or for unrelated reasons. Familiarity with these devices and their CT characteristics will increase diagnostic confidence and the value of the radiology report. The authors describe the physical and imaging properties of the currently commercially available THVs, their normal postprocedural imaging appearances, and potential complications that can be detected at CT. In addition, they discuss the relative strengths and weaknesses of CT and echocardiography in this setting. ©RSNA, 2014.
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Coronary Artery Calcification Scoring with State-of-the-Art CT Scanners from Different Vendors Has Substantial Effect on Risk Classification.
Radiology
PUBLISHED: 08-22-2014
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Purpose To determine the intervendor variability of Agatston scoring determined with state-of-the-art computed tomographic (CT) systems from the four major vendors in an ex vivo setup and to simulate the subsequent effects on cardiovascular risk reclassification in a large population-based cohort. Materials and Methods Research ethics board approval was not necessary because cadaveric hearts from individuals who donated their bodies to science were used. Agatston scores obtained with CT scanners from four different vendors were compared. Fifteen ex vivo human hearts were placed in a phantom resembling an average human adult. Hearts were scanned at equal radiation dose settings for the systems of all four vendors. Agatston scores were quantified semiautomatically with software used clinically. The ex vivo Agatston scores were used to simulate the effects of different CT scanners on reclassification of 432 individuals aged 55 years or older from a population-based study who were at intermediate cardiovascular risk based on Framingham risk scores. The Friedman test was used to evaluate overall differences, and post hoc analyses were performed by using the Wilcoxon signed-rank test with Bonferroni correction. Results Agatston scores differed substantially when CT scanners from different vendors were used, with median Agatston scores ranging from 332 (interquartile range, 114-1135) to 469 (interquartile range, 183-1381; P < .05). Simulation showed that these differences resulted in a change in cardiovascular risk classification in 0.5%-6.5% of individuals at intermediate risk when a CT scanner from a different vendor was used. Conclusion Among individuals at intermediate cardiovascular risk, state-of the-art CT scanners made by different vendors produced substantially different Agatston scores, which can result in reclassification of patients to the high- or low-risk categories in up to 6.5% of cases. © RSNA, 2014.
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[The future of the CT scan; will CT replace conventional radiography?].
Ned Tijdschr Geneeskd
PUBLISHED: 08-21-2014
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The number of CT scans being made has increased over the past few years. New CT technology has been developed to reduce the individual patient radiation dose. By using this technology it is possible to make CT scans with a radiation dose approaching conventional X-rays, which means that in the future radiation dose may not form a limitation to making CT scans. The indication for CT scans will broaden, and low-dose CT scans will increasingly replace conventional radiography.
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Extracellular vesicle protein CD14 relates to common carotid intima-media thickness in eight year old children.
Atherosclerosis
PUBLISHED: 07-28-2014
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Atherosclerosis is a process that begins in childhood, develops over decades and underlies the majority of cardiovascular events in adulthood. Previously, we demonstrated in adults with cardiovascular disease that levels of extracellular vesicle (EV) proteins CD14, Serpin F2 and cystatin C predict vascular outcome. Here, we study for the first time whether these EV proteins are related to vascular characteristics in healthy, young children.
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Computed tomography radiation dose reduction: effect of different iterative reconstruction algorithms on image quality.
J Comput Assist Tomogr
PUBLISHED: 07-02-2014
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We evaluated the effects of hybrid and model-based iterative reconstruction (IR) algorithms from different vendors at multiple radiation dose levels on image quality of chest phantom scans.
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Dose reduction for coronary calcium scoring with hybrid and model-based iterative reconstruction: an ex vivo study.
Int J Cardiovasc Imaging
PUBLISHED: 04-26-2014
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To determine the influence of dose reduction on coronary calcium scoring using hybrid and model-based iterative reconstruction (IR) techniques.
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Feasibility and reproducibility of free fatty acid profiling in abdominal adipose tissue with 1H-magnetic resonance spectroscopy at 3 T: differences between lean and obese individuals.
J Magn Reson Imaging
PUBLISHED: 04-23-2014
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To evaluate the feasibility and reproducibility of free fatty acid (FFA) measurement for diagnosing adipose tissue dysfunction by (1)H-magnetic resonance spectroscopy ((1)H-MRS) in different abdominal adipose tissue depots in healthy obese and lean subjects.
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Coronary artery assessment on electrocardiogram-gated thoracoabdominal multidetector computed tomographic angiography for aortic evaluation.
J Comput Assist Tomogr
PUBLISHED: 03-15-2014
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The objective of this study was to evaluate coronary image quality, stenosis grade, and diagnostic confidence in patients undergoing electrocardiogram-gated thoracoabdominal multidetector computed tomographic angiography (CTA) for aortic evaluation.
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Inhibition of the renin-angiotensin system affects kidney tissue oxygenation evaluated by magnetic resonance imaging in patients with chronic kidney disease.
J Clin Hypertens (Greenwich)
PUBLISHED: 02-20-2014
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Imaging of the kidney using blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) presents a major opportunity to examine differences in tissue oxygenation within the cortex and medulla applicable to human disease. The aim of this study was to evaluate BOLD signals before and after treatment with RAS inhibitors in hypertensive chronic kidney disease (CKD) patients. Ten patients with stable CKD and 5 healthy volunteers were included. Five CKD patients were subjected to BOLD MRI scan before and after chronic treatment with 300 mg/day aliskiren for at least 6 weeks. Five other CKD patients received BOLD MRI before and 1 hour after acute treatment with 50 mg captopril. A group of healthy volunteers (n=5) was scanned before and 1 hour after acute treatment with 50 mg captopril. The 10 patients had a mean age of 61±17 years; eGFR of 30±11 mL/min per 1.73 m(2) . Office systolic and diastolic blood pressures when on a RAS inhibito, were 130±10 and 86±5 mmHg in CKD patients. Control subjects had normal kidney function and were not on any medication. In untreated condition, systolic and diastolic arterial blood pressure elevated, 145±6 and 95±4 mmHg, respectively. After chronic treatment with aliskiren, arterial blood pressure decreased in all patients in this group, 127±3 mmHg and 77±3 mmHg. After acute treatment with captopril arterial blood pressure reduced to 125±4 and 71±8 mmHg. Tissue intensity signal (T2*) was increased in medulla after chronic treatment from 29±6 to 34±6 and after acute treatment with captopril from 34±9 to 38±11 in CKD patients. In addition, T2* ratio between cortex and medulla decreased in CKD patients after chronic treatment and acute treatment. This ratio remained stable in healthy volunteers before and after treatment with captopril 1.62±0.1 and 1.65±0.1, respectively. This study shows for the first time that RAS inhibitors change BOLD signal in CKD patients. Importantly, in healthy volunteers, a RAS inhibitor had no such effect. Further investigation is required.
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Cardiac magnetic resonance imaging findings and the risk of cardiovascular events in patients with recent myocardial infarction or suspected or known coronary artery disease: a systematic review of prognostic studies.
J. Am. Coll. Cardiol.
PUBLISHED: 01-30-2014
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The goal of this study was to review the prognostic value of cardiac magnetic resonance (CMR) imaging findings for future cardiovascular events in patients with a recent myocardial infarction (MI) and patients with suspected or known coronary artery disease (CAD). Although the diagnostic value of CMR findings is established, the independent prognostic association with future cardiovascular events remains largely unclear. Studies published by February 2013, identified by systematic MEDLINE and EMBASE searches, were reviewed for associations between CMR findings (left ventricular ejection fraction [LVEF], wall motion abnormalities [WMA], abnormal myocardial perfusion, microvascular obstruction, late gadolinium enhancement, edema, and intramyocardial hemorrhage) and hard events (all-cause mortality, cardiac death, cardiac transplantation, and MI) or major adverse cardiovascular events (MACE) (hard events and other cardiovascular events defined by the authors of the evaluated papers). Fifty-six studies (n = 25,497) were evaluated. For patients with recent MI, too few patients were evaluated to establish associations between CMR findings and hard events. LVEF (range of adjusted hazard ratios [HRs]: 1.03 to 1.05 per % decrease) was independently associated with MACE. In patients with suspected or known CAD, WMA (adjusted HRs: 1.87 to 2.99), inducible perfusion defects (adjusted HRs: 3.02 to 7.77), LVEF (adjusted HRs: 0.72 to 0.82 per 10% increase), and infarction (adjusted HRs: 2.82 to 9.43) were independently associated with hard events, and the presence of inducible perfusion defects was associated with MACE (adjusted HRs: 1.76 to 3.21). The independent predictor of future cardiovascular events for patients with a recent MI was LVEF, and the predictors for patients with suspected or known CAD were WMA, inducible perfusion defects, LVEF, and presence of infarction.
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The impact of a new model-based iterative reconstruction algorithm on prosthetic heart valve related artifacts at reduced radiation dose MDCT.
Int J Cardiovasc Imaging
PUBLISHED: 01-20-2014
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To assess the impact of hybrid iterative reconstruction (IR) and novel model-based iterative reconstruction (IMR) and dose reduction on prosthetic heart valve (PHV) related artifacts and objective image quality. One transcatheter and two mechanical PHVs were embedded in diluted contrast-gel, inserted in an anthropomorphic phantom and imaged stationary with retrospectively ECG-gated computed tomography. Eight acquisitions were obtained of each PHV at 120 kV, 600 mAs (routine), 300 and 150 mAs (reduced dose). Data were reconstructed with filtered back projection (FBP), IR and IMR. Hypodense and hyperdense artifact volumes were quantified using two threshold filters. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Artifact volumes differed significantly between reconstruction algorithms for all PHVs (P < 0.005). Compared to FBP, IR decreased overall hypodense and hyperdense artifact volumes; at 150 mAs by 53 and 20 % (IR) and 67 and 23 % (IMR), respectively and significantly increased SNR and CNR at all doses (P < 0.012). Even at reduced dose, IMR resulted in higher image quality than routine dose FBP and IR. Iterative reconstruction and particularly IMR significantly reduce PHV-related artifacts and improve objective image quality in non-pulsatile conditions, even in reduced-dose images. Also, this study suggests that IMR allows for more radiation dose reduction in comparison to hybrid IR while maintaining high image quality.
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Pressure overloaded right ventricles: a multicenter study on the importance of trabeculae in RV function measured by CMR.
Int J Cardiovasc Imaging
PUBLISHED: 01-12-2014
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Cardiac magnetic resonance (CMR) imaging is the preferred method to measure right ventricular (RV) volumes and ejection fraction (RVEF). This study aimed to determine the impact of excluding trabeculae and papillary muscles on RV volumes and function in patients with RV pressure and/or volume overload and healthy controls and its reproducibility using semi-automatic software. Eighty patients (pulmonary hypertension, transposition of the great arteries after arterial switch operation and after atrial switch procedure and repaired Tetralogy of Fallot) and 20 controls underwent short-axis multislice cine CMR. End diastolic volume (EDV), end systolic volume (ESV), RV mass and RVEF were measured using 2 methods. First, manual contour tracing of RV endo- and epi-cardial borders was performed. Thereafter, trabeculae were excluded from the RV blood volume using semi-automatic pixel-intensity based software. Both methods were compared using a Student T test and 25 datasets were re-analyzed for reproducibility. Exclusion of trabeculae resulted in significantly decreased EDV; ranging from -5.7 ± 1.7 ml/m(2) in controls to -29.2 ± 6.6 ml/m(2) in patients after atrial switch procedure. RVEF significantly increased in all groups, ranging from an absolute increase of 3.4 ± 0.8 % in healthy controls to 10.1 ± 2.3 % in patients after atrial switch procedure. Interobserver agreement of method 2 was equal to method 1 for RVEDV, RVESV and RVEF and superior for RV mass. In patients with overloaded RVs exclusion of trabeculae from the blood volume results in a significant change in RV volumes, RVEF and RV mass. Exclusion of trabeculae is highly reproducible when semi-automatic pixel-intensity based software is used.
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Cardiac valve calcifications on low-dose unenhanced ungated chest computed tomography: inter-observer and inter-examination reliability, agreement and variability.
Eur Radiol
PUBLISHED: 01-07-2014
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To determine inter-observer and inter-examination variability for aortic valve calcification (AVC) and mitral valve and annulus calcification (MC) in low-dose unenhanced ungated lung cancer screening chest computed tomography (CT).
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Automated coronary artery calcification scoring in non-gated chest CT: agreement and reliability.
PLoS ONE
PUBLISHED: 01-01-2014
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To determine the agreement and reliability of fully automated coronary artery calcium (CAC) scoring in a lung cancer screening population.
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Functional MRI in peripheral arterial disease: arterial peak flow versus ankle-brachial index.
PLoS ONE
PUBLISHED: 01-01-2014
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The purpose of this study was to compare the success rate of successful arterial peak flow (APF) and ankle-brachial index (ABI) measurements in patients with suspected or known peripheral arterial disease (PAD).
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[CT scans in children and adolescents: only when appropriate and when optimized].
Ned Tijdschr Geneeskd
PUBLISHED: 12-05-2013
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Radiation exposure due to medical imaging has more than doubled in the Netherlands since the early 1990s. There is increasing evidence that this is not without risk, especially in children and adolescents. A recent study in over 680,000 Australians < 19 years old at the time of imaging provides further evidence that CT scanning may induce excess cancer. In light of these findings it is of paramount importance that physicians dealing with this patient population only request CT studies if imaging is clearly indicated. New technological developments such as iterative reconstruction will ameliorate the risk for low radiation-dose malignancies, but continued vigilance is necessary.
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The effect of iterative reconstruction on quantitative computed tomography assessment of coronary plaque composition.
Int J Cardiovasc Imaging
PUBLISHED: 07-04-2013
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To compare coronary plaque size and composition as well as degree of coronary artery stenosis on coronary Computed Tomography angiography (CCTA) using three levels of iterative reconstruction (IR) with standard filtered back projection (FBP). In 63 consecutive patients with a clinical indication for CCTA 55 coronary plaques were analysed. Raw data were reconstructed using standard FBP and levels 2, 4 and 6 of a commercially available IR algorithm (iDose(4)). CT attenuation and noise were measured in the aorta and two coronary arteries. Both signal-to-noise-ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The amount of lipid, fibrous and calcified plaque components and mean cross-sectional luminal area were analysed using dedicated software. Image noise was reduced by 41.6 % (p < 0.0001) and SNR and CNR in the aorta were improved by 73.4 % (p < 0.0001) and 72.9 % (p < 0.0001) at IR level 6, respectively. IR improved objective image quality measures more in the aorta than in the coronary arteries. Furthermore, IR had no significant effect on measurements of plaque volume and cross-sectional luminal area. The application of IR significantly improves objective image quality, and does not alter quantitative analysis of coronary plaque volume, composition and luminal area.
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Quantification of abdominal aortic aneurysm wall enhancement with dynamic contrast-enhanced MRI: Feasibility, reproducibility, and initial experience.
J Magn Reson Imaging
PUBLISHED: 06-04-2013
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To investigate the feasibility and reproducibility of dynamic contrast-enhanced MRI (DCE-MRI) to quantify abdominal aortic aneurysm (AAA) vessel wall enhancement dynamics which may reflect the amount of wall microvasculature. AAA vessel wall microvasculature has been linked with aneurysm progression and rupture.
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Magnetic resonance imaging-based monitoring of collateral artery development in patients with intermittent claudication during supervised exercise therapy.
J. Vasc. Surg.
PUBLISHED: 03-21-2013
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The purpose of the current study was to determine whether supervised exercise therapy (SET) leads to measurable vascular adaptations in patients with intermittent claudication using contrast-enhanced magnetic resonance angiography and flow measurements.
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Subtractionless first-pass single contrast medium dose peripheral MR angiography using two-point Dixon fat suppression.
Eur Radiol
PUBLISHED: 02-14-2013
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To investigate the feasibility of subtractionless first-pass single contrast medium dose (0.1 mmol/kg) peripheral magnetic resonance angiography (MRA) at 1.5 T using two-point Dixon fat suppression and compare it with conventional subtraction MRA in terms of image quality.
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The effects of computed tomography with iterative reconstruction on solid pulmonary nodule volume quantification.
PLoS ONE
PUBLISHED: 01-30-2013
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The objectives of this study were to evaluate the influence of iterative reconstruction (IR) on pulmonary nodule volumetry with chest computed tomography (CT).
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Iterative reconstruction does not substantially delay CT imaging in an emergency setting.
Insights Imaging
PUBLISHED: 01-29-2013
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To evaluate the effects of iterative reconstruction (IR) on reconstruction time and speed in two commonly encountered acquisition protocols in an emergency setting: pulmonary CT angiography (CTA) and total body trauma CT.
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Iterative reconstruction techniques for computed tomography part 2: initial results in dose reduction and image quality.
Eur Radiol
PUBLISHED: 01-16-2013
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To present the results of a systematic literature search aimed at determining to what extent the radiation dose can be reduced with iterative reconstruction (IR) for cardiopulmonary and body imaging with computed tomography (CT) in the clinical setting and what the effects on image quality are with IR versus filtered back-projection (FBP) and to provide recommendations for future research on IR.
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Iterative reconstruction techniques for computed tomography Part 1: technical principles.
Eur Radiol
PUBLISHED: 01-12-2013
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To explain the technical principles of and differences between commercially available iterative reconstruction (IR) algorithms for computed tomography (CT) in non-mathematical terms for radiologists and clinicians.
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Suitability of pharmacokinetic models for dynamic contrast-enhanced MRI of abdominal aortic aneurysm vessel wall: a comparison.
PLoS ONE
PUBLISHED: 01-01-2013
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Increased microvascularization of the abdominal aortic aneurysm (AAA) vessel wall has been related to AAA progression and rupture. The aim of this study was to compare the suitability of three pharmacokinetic models to describe AAA vessel wall enhancement using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).
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Equilibrium-phase high spatial resolution contrast-enhanced MR angiography at 1.5T in preoperative imaging for perforator flap breast reconstruction.
PLoS ONE
PUBLISHED: 01-01-2013
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The aim was (i) to evaluate the accuracy of equilibrium-phase high spatial resolution (EP) contrast-enhanced magnetic resonance angiography (CE-MRA) at 1.5T using a blood pool contrast agent for the preoperative evaluation of deep inferior epigastric artery perforator branches (DIEP), and (ii) to compare image quality with conventional first-pass CE-MRA.
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Performance of angiographic, electrocardiographic and MRI methods to assess the area at risk in acute myocardial infarction.
Heart
PUBLISHED: 09-19-2011
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Objective Validation of methods to assess the area at risk (AAR) in patients with ST elevation myocardial infarction is limited. A study was undertaken to test different AAR methods using established physiological concepts to provide a reference standard. Main outcome measured In 78 reperfused patients with first ST elevation myocardial infarction, AAR was measured by electrocardiographic (Aldrich), angiographic (Bypass Angioplasty Revascularization Investigation (BARI), APPROACH) and cardiovascular magnetic resonance methods (T2-weighted hyperintensity and delayed enhanced endocardial surface area (ESA)). The following established physiological concepts were used to evaluate the AAR METHODS: (1) AAR size is always ? infarct size (IS); (2) in transmural infarcts AAR size=IS; (3) correlation between AAR size and IS increases as infarct transmurality increases; and (4) myocardial salvage ((AAR-IS)/AAR×100) is inversely related to infarct transmurality. Results Overall, 65%, 87%, 76%, 87% and 97% of patients using the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods obeyed the concept that AAR size is ?IS. In patients with transmural infarcts (n=22), Bland-Altman analysis showed poor agreement (wide 95% limits of agreement) between AAR size and IS for the BARI, Aldrich and APPROACH methods (95% CI -22.9 to 29.6, 95% CI -28.3 to 21.3 and 95% CI -16.9 to 20.0, respectively) and better agreement for T2-weighted hyperintensity and ESA (95% CI -6.9 to 16.6 and 95% CI -4.3 to 18.0, respectively). Increasing correlation between AAR size and IS with increasing infarct transmurality was observed for the APPROACH, T2-weighted hyperintensity and ESA methods, with ESA having the highest correlation (r=0.93, p<0.001). The percentage of patients within a narrow margin (±30%) of the inverse line of identity between salvage extent and infarct transmurality was 56%, 76%, 65%, 77% and 92% for the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods, respectively, where higher percentages represent better concordance with the concept that the extent of salvage should be inversely related to infarct transmurality. Conclusions For measuring AAR, cardiovascular magnetic resonance methods are better than angiographic methods, which are better than electrocardiographic methods. Overall, ESA performed best for measuring AAR in vivo.
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Automated multiscale vessel analysis for the quantification of MR angiography of peripheral arteriogenesis.
J Magn Reson Imaging
PUBLISHED: 08-24-2011
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To automatically analyze the time course of collateralization in a rat hindlimb ischemia model based on signal intensity distribution (SID).
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Nephrogenic systemic fibrosis: review of 370 biopsy-confirmed cases.
JACC Cardiovasc Imaging
PUBLISHED: 08-10-2011
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Discovery of an association between gadolinium-based contrast agents (GBCAs) and nephrogenic systemic fibrosis (NSF) has led to less use of GBCA-enhanced magnetic resonance imaging in dialysis patients and patients with severe renal failure at risk of NSF, and the virtual elimination of new cases of NSF. But shifting patients with renal failure to alternative imaging methods may subject patients to other risks (e.g., ionizing radiation or iodinated contrast). This review paper examines 370 NSF cases reported in 98 articles to analyze NSF risk factors. Eliminating multiple risk factors by limiting GBCA dose to a maximum of 0.1 mmol/kg, dialyzing patients undergoing dialysis quickly following GBCA administration, delaying GBCA in acute renal failure until after renal function returns or dialysis is initiated, and avoiding nonionic linear GBCA in patients with renal failure especially when there are proinflammatory conditions may substantially reduce the risk of NSF.
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Time-efficient black blood RCA wall imaging at 3T using improved motion sensitized driven equilibrium (iMSDE): feasibility and reproducibility.
PLoS ONE
PUBLISHED: 05-23-2011
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The aim of this study was to explore the feasibility and reproducibility of a time-efficient coronary vessel wall measurement approach using an improved motion-sensitized driven equilibrium (iMSDE) pulse sequence.
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A novel iterative reconstruction algorithm allows reduced dose multidetector-row CT imaging of mechanical prosthetic heart valves.
Int J Cardiovasc Imaging
PUBLISHED: 05-02-2011
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Multidetector-row CT is promising for prosthetic heart valve (PHV) assessment but retrospectively ECG-gated scanning has a considerable radiation dose. Recently introduced iterative reconstruction (IR) algorithms may enable radiation dose reduction with retained image quality. Furthermore, PHV image quality on the CT scan mainly depends on extent of PHV artifacts. IR may decrease streak artifacts. We compared image noise and artifact volumes in scans of mechanical PHVs reconstructed with conventional filtered back projection (FBP) to lower dose scans reconstructed with IR. Four different PHVs (St. Jude, Carbomedics, ON-X and Medtronic Hall) were scanned in a pulsatile in vitro model. Ten retrospectively ECG-gated CT scans were performed of each PHV at 120 kV, 600 mAs (high-dose CTDI(vol) 35.3 mGy) and 120 kV, 300 mAs (low-dose CTDI(vol) 17.7 mGy) on a 64 detector-row scanner. Diastolic and systolic images were reconstructed with FBP (high and low-dose) and the IR algorithm (low-dose only). Hypo- and hyperdense artifact volumes were determined using two threshold filters. Image noise was measured. Mean hypo- and hyperdense artifact volumes (mm(3)) were 1,235/5,346 (high-dose FBP); 2,405/6,877 (low-dose FBP) and 1,218/5,333 (low-dose IR). Low-dose IR reconstructions had similar image noise compared to high-dose FBP (16.5 ± 1.7 vs. 16.3 ± 1.6, mean ± SD, respectively, P = 1.0). IR allows ECG-gated PHV imaging with similar image noise and PHV artifacts at 50% less dose compared to conventional FBP in an pulsatile in vitro model.
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Magnetic resonance imaging in peripheral arterial disease: reproducibility of the assessment of morphological and functional vascular status.
Invest Radiol
PUBLISHED: 04-06-2011
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The aim of the current study was to test the reproducibility of different quantitative magnetic resonance imaging (MRI) methods to assess the morphologic and functional peripheral vascular status and vascular adaptations over time in patients with peripheral arterial disease (PAD).
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Cardiac lipid content is unresponsive to a physical activity training intervention in type 2 diabetic patients, despite improved ejection fraction.
Cardiovasc Diabetol
PUBLISHED: 03-14-2011
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Increased cardiac lipid content has been associated with diabetic cardiomyopathy. We recently showed that cardiac lipid content is reduced after 12 weeks of physical activity training in healthy overweight subjects. The beneficial effect of exercise training on cardiovascular risk is well established and the decrease in cardiac lipid content with exercise training in healthy overweight subjects was accompanied by improved ejection fraction. It is yet unclear whether diabetic patients respond similarly to physical activity training and whether a lowered lipid content in the heart is necessary for improvements in cardiac function. Here, we investigated whether exercise training is able to lower cardiac lipid content and improve cardiac function in type 2 diabetic patients.
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MR angiography of collateral arteries in a hind limb ischemia model: comparison between blood pool agent Gadomer and small contrast agent Gd-DTPA.
PLoS ONE
PUBLISHED: 01-26-2011
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The objective of this study was to compare the blood pool agent Gadomer with a small contrast agent for the visualization of ultra-small, collateral arteries (diameter<1 mm) with high resolution steady-state MR angiography (SS-MRA) in a rabbit hind limb ischemia model. Ten rabbits underwent unilateral femoral artery ligation. On days 14 and 21, high resolution SS-MRA (voxel size 0.49×0.49×0.50 mm(3)) was performed on a 3 Tesla clinical system after administration of either Gadomer (dose: 0.10 mmol/kg) or a small contrast agent (gadopentetate dimeglumine (Gd-DTPA), dose: 0.20 mmol/kg). All animals received both contrast agents on separate days. Selective intra-arterial x-ray angiograms (XRAs) were obtained in the ligated limb as a reference. The number of collaterals was counted by two independent observers. Image quality was evaluated with the contrast-to-noise ratio (CNR) in the femoral artery and collateral arteries. CNR for Gadomer was higher in both the femoral artery (Gadomer: 73±5 (mean ± SE); Gd-DTPA: 40±3; p<0.01) and collateral arteries (Gadomer: 18±4; Gd-DTPA: 9±1; p?=?0.04). Neither day of acquisition nor contrast agent used influenced the number of identified collateral arteries (p?=?0.30 and p?=?0.14, respectively). An average of 4.5±1.0 (day 14, mean ± SD) and 5.3±1.2 (day 21) collaterals was found, which was comparable to XRA (5.6±1.7, averaged over days 14 and 21; p>0.10). Inter-observer variation was 24% and 18% for Gadomer and Gd-DTPA, respectively. In conclusion, blood pool agent Gadomer improved vessel conspicuity compared to Gd-DTPA. Steady-state MRA can be considered as an excellent non-invasive alternative to intra-arterial XRA for the visualization of ultra-small collateral arteries.
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Accuracy of gadofosveset-enhanced MRI for nodal staging and restaging in rectal cancer.
Ann. Surg.
PUBLISHED: 01-18-2011
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To prospectively assess the accuracy of gadofosveset-enhanced magnetic resonance imaging (MRI) for nodal staging and restaging in rectal cancer.
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Optimized pharmacokinetic modeling for the detection of perfusion differences in skeletal muscle with DCE-MRI: effect of contrast agent size.
Med Phys
PUBLISHED: 12-17-2010
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The goal of this study was to optimize dynamic contrast-enhanced (DCE)-MRI analysis for differently sized contrast agents and to evaluate the sensitivity for microvascular differences in skeletal muscle.
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Multicenter, double-blind, randomized, intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for MR angiography of peripheral arteries.
Radiology
PUBLISHED: 05-27-2010
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To prospectively compare the image quality and diagnostic performance achieved with doses of gadobenate dimeglumine and gadopentetate dimeglumine of 0.1 mmol per kilogram of body weight in patients undergoing contrast material-enhanced magnetic resonance (MR) angiography of the pelvis, thigh, and lower-leg (excluding foot) for suspected or known peripheral arterial occlusive disease.
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Visualization of coronary wall atherosclerosis in asymptomatic subjects and patients with coronary artery disease using magnetic resonance imaging.
PLoS ONE
PUBLISHED: 04-26-2010
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Magnetic resonance imaging (MRI) is sensitive to early atherosclerotic changes such as positive remodeling in patients with coronary artery disease (CAD). We assessed prevalence, quality, and extent of coronary atherosclerosis in a group of healthy subjects compared to patients with confirmed CAD.
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Chronic coumarin treatment is associated with increased extracoronary arterial calcification in humans.
Blood
PUBLISHED: 03-30-2010
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Vascular calcification is a marker of increased cardiovascular risk. Vitamin K-dependent matrix Gla protein (MGP) is important in inhibiting calcification. Because MGP activation is vitamin K dependent, we performed a cross-sectional study investigating the relationship between the use of vitamin K antagonists and extracoronary vascular calcification. From the Dutch thrombosis services we selected 19 patients younger than 55 years who had no other cardiovascular risk factors and who had used coumarins for more than 10 years, and compared these to 18 matched healthy controls. MGP was measured, and a plain x-ray of the thighs was taken to assess femoral arterial calcifications. The odds ratio for calcification in patients versus controls was 8.5 (95% confidence interval [CI] 2.01-35.95). Coumarin use and MGP were associated with calcification, even after adjusting for other risk factors. We conclude that long-term use of coumarins is associated with enhanced extracoronary vascular calcification, possibly through the inhibition of MGP carboxylation.
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The extent of coronary atherosclerosis is associated with increasing circulating levels of high sensitive cardiac troponin T.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 03-18-2010
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This study explored the relationship between coronary atherosclerotic plaque burden and quantifiable circulating levels of troponin measured with a recently introduced high sensitive cardiac troponin T (hs-cTnT) assay.
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Clinical implications of microvascular obstruction and intramyocardial haemorrhage in acute myocardial infarction using cardiovascular magnetic resonance imaging.
Eur Radiol
PUBLISHED: 02-10-2010
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To investigate the clinical implications of microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH) in acute myocardial infarction (AMI).
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NSF prevention in clinical practice: summary of recommendations and guidelines in the United States, Canada, and Europe.
J Magn Reson Imaging
PUBLISHED: 11-26-2009
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In this article we summarize recommendations and guidelines for the prevention of NSF from the United States, Canada, and Europe. J. Magn. Reson. Imaging 2009;30:1357-1363. (c) 2009 Wiley-Liss, Inc.
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Risk factors for NSF: a literature review.
J Magn Reson Imaging
PUBLISHED: 11-26-2009
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Emerging evidence linking gadolinium-based contrast agents (GBCAs) to nephrogenic systemic fibrosis (NSF) has changed medical practice patterns toward forgoing GBCA-enhanced magnetic resonance imaging (MRI) or substituting other imaging methods, which are potentially less accurate and often radiation-based. This shift has been based on reports of high NSF incidence at sites where a confluence of risk factors occurred in patients with severe renal dysfunction. This review article explores the factors that affect NSF risk, compares risks of alternative imaging procedures, and demonstrates how risk can be managed by careful selection of GBCA dose, timing of injection with respect to dialysis, and other factors. Nearly half of NSF cases are a milder form that does not cause contractures or reduce mobility. It appears that eliminating even a single risk factor can reduce NSF incidence/risk at least 10-fold. Elimination of multiple risk factors by using single-dose GBCA, dialyzing dialysis patients quickly following GBCA administration, avoiding GBCA in acute renal failure while serum creatinine is rising, and avoiding nonionic linear GBCA in renal failure patients may reduce NSF risk more than a thousand-fold, thereby allowing safe GBCA-enhanced MRI in virtually all patients. J. Magn. Reson. Imaging 2009;30:1298-1308. (c) 2009 Wiley-Liss, Inc.
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Highly accelerated first-pass contrast-enhanced magnetic resonance angiography of the peripheral vasculature: comparison of gadofosveset trisodium with gadopentetate dimeglumine contrast agents.
J Magn Reson Imaging
PUBLISHED: 10-27-2009
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To investigate the blood pool agent gadofosveset trisodium for first-pass, dynamic peripheral contrast-enhanced magnetic resonance angiography (pMRA), and compare the results with a conventional gadolinium contrast agent.
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Reliability of pharmacokinetic parameters: small vs. medium-sized contrast agents.
Magn Reson Med
PUBLISHED: 07-23-2009
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Current clinical applications of dynamic contrast-enhanced MRI (DCE-MRI) are based on the extravasation of relatively small contrast agents (SCAs). SCAs are considered disadvantageous, as they require high image sampling rates. Medium-sized contrast agents (MCAs) leak more slowly into tissue and allow longer dynamic acquisition times, enabling improved image quality. The influence of molecular size on the reliability of pharmacokinetic parameters, including the transfer constant K(trans), was investigated. Computer simulations were performed, with in vivo measured arterial input functions (AIFs), to determine the bias and variance of pharmacokinetic parameters as a function of contrast agent size, sampling frequency, noise level, and acquisition time. Better reliability of all parameters was obtained for the MCA compared to the SCA. To obtain similar variance (10%) in K(trans), the sampling frequency for the SCA (28 min(-1)) had to be 20 times faster than for the MCA (1.3 min(-1)). Optimal reliability in parameter estimation required longer acquisition times for MCAs (13 min for the fraction of the extravascular extracellular space into which the contrast agent distributes (v(e)) and 5 min for K(trans)) than for SCAs (1.7 min for K(trans) and v(e)). Reliable estimation of the fractional blood plasma volume (v(p)) was only achieved with MCAs. In conclusion, MCAs provided superior reliability for pharmacokinetic parameter estimation compared to SCAs.
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Atherosclerosis: contrast-enhanced MR imaging of vessel wall in rabbit model--comparison of gadofosveset and gadopentetate dimeglumine.
Radiology
PUBLISHED: 02-27-2009
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To investigate the potential of gadofosveset for contrast material-enhanced magnetic resonance (MR) imaging of plaque in a rabbit model of atherosclerosis.
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Systematic error in lung nodule volumetry: effect of iterative reconstruction versus filtered back projection at different CT parameters.
AJR Am J Roentgenol
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Iterative reconstruction potentially can reduce radiation dose compared with filtered back projection (FBP) for chest CT. This is especially important for repeated CT scanning, as is the case in patients with indeterminate lung nodules. It is currently unknown whether absolute nodule volumes measured with iterative reconstruction are comparable to those measured with FBP. We compared nodule volumes measured with iterative reconstruction and FBP at different CT parameters.
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Relation between mild to moderate chronic kidney disease and coronary artery disease determined with coronary CT angiography.
PLoS ONE
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Both end-stage and milder stages of chronic kidney disease (CKD) are associated with an increased risk of adverse cardiovascular events. Several studies found an association between decreasing renal function and increasing coronary artery calcification, but it remains unclear if this association is independent from traditional cardiovascular risk factors. Therefore, the aim of this study was to investigate whether mild to moderate CKD is independently associated with coronary plaque burden beyond traditional cardiovascular risk factors.
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Iterative reconstruction improves evaluation of native aortic and mitral valves by retrospectively ECG-gated thoracoabdominal CTA.
Eur Radiol
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To compare native aortic (AV) and mitral valve (MV) image quality on limited-dose retrospectively ECG-gated CTA of the thoracoabdominal aorta reconstructed with iterative reconstruction (IR) and filtered back projection (FBP).
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Can low-dose unenhanced chest CT be used for follow-up of lung nodules?
AJR Am J Roentgenol
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The purpose of this study is to establish the difference in lung nodule volume between standard-dose contrast-enhanced and low-dose unenhanced CT.
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Detection of coronary plaques using MR coronary vessel wall imaging: validation of findings with intravascular ultrasound.
Eur Radiol
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Compared with X-ray coronary angiography (CAG), magnetic resonance imaging of the coronary vessel wall (MR-CVW) may provide more information about plaque burden and coronary remodelling. We compared MR-CVW with intravascular ultrasound (IVUS), the standard of reference for coronary vessel wall imaging, with regard to plaque detection and wall thickness measurements.
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Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings.
PLoS ONE
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The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) to assess the microvascular status in patients with peripheral arterial disease (PAD) and healthy controls. In addition, the reproducibility of this method in healthy controls was determined.
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The effect of iterative reconstruction on computed tomography assessment of emphysema, air trapping and airway dimensions.
Eur Radiol
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To determine the influence of iterative reconstruction (IR) on quantitative computed tomography (CT) measurements of emphysema, air trapping, and airway wall and lumen dimensions, compared to filtered back-projection (FBP).
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Diagnostic performance of noninvasive myocardial perfusion imaging using single-photon emission computed tomography, cardiac magnetic resonance, and positron emission tomography imaging for the detection of obstructive coronary artery disease: a meta-anal
J. Am. Coll. Cardiol.
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This study aimed to determine the diagnostic accuracy of the 3 most commonly used noninvasive myocardial perfusion imaging modalities, single-photon emission computed tomography (SPECT), cardiac magnetic resonance (CMR), and positron emission tomography (PET) perfusion imaging for the diagnosis of obstructive coronary artery disease (CAD). Additionally, the effect of test and study characteristics was explored.
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Artifact reduction strategies for prosthetic heart valve CT imaging.
Int J Cardiovasc Imaging
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Multislice CT evaluation of prosthetic heart valves (PHV) is limited by PHV-related artifacts. We assessed the influence of different kV settings, a metal artifact reduction filter (MARF) and an iterative reconstruction algorithm (IR) on PHV-induced artifacts in an in vitro model. A Medtronic-Hall tilting disc and St Jude bileafet PHV were imaged using a 64-slice scanner with 100 kV/165 mAs, 120 kV/100 mAs, 140 kV/67 mAs at an equal CTDI(vol). Images were reconstructed with (1) filtered back projection (FBP), (2) IR, (3) MARF and (4) MARF and IR. Hypo- and hyperdense artifacts volumes (mean mm(3) ± SD) were quantified with 2 thresholds (?-50 and ?175 Hounsfield Units). Image noise was measured and the presence of secondary artifacts was scored by 2 observers independently. Mean hypodense artifacts for the Medtronic-Hall/St Jude valve (FBP) were 966 ± 23/1,738 ± 21 at 100 kV, 610 ± 13/991 ± 12 at 120 kV, and 420 ± 9/634 ± 9 at 140 kV. Compared to FBP, hypodense artifact reductions for IR were 9/8 %, 10/7 % and 12/6 % respectively, for MARF 92 %/84 %, 89/81 % and 86/77 % respectively; for MARF + IR 94/85 %, 92/82 %, and 90/79 % respectively. Mean hyperdense artifacts for the Medtronic-Hall/St Jude valve were 5,530 ± 48/6,940 ± 70 at 100 kV, 5,120 ± 42/6,250 ± 53 at 120 kV, and 5,011 ± 52/6,000 ± 0 at 140 kV. Reductions for IR were 2/2 %, 2/3 % and 3/4 % respectively, for MARF were 9/30 %, 0/25 %, 5/22 % respectively, MARF + IR 12/32 %, 4/27 % and 7/25 % respectively. Secondary artifacts were found in all MARF images. Image noise was reduced in the IR images. In vitro PHV-related artifacts can be reduced by increasing kV despite maintaining identical CTDI(vol). Although MARF is more effective than IR, it induces secondary artifacts.
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MRI of arterial flow reserve in patients with intermittent claudication: feasibility and initial experience.
PLoS ONE
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The aim of this work was to develop a MRI method to determine arterial flow reserve in patients with intermittent claudication and to investigate whether this method can discriminate between patients and healthy control subjects.
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Epicardial adipose tissue volume as a predictor for coronary artery disease in diabetic, impaired fasting glucose, and non-diabetic patients presenting with chest pain.
Eur Heart J Cardiovasc Imaging
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Epicardial adipose tissue (EAT) volume has been associated with coronary artery disease (CAD). As diabetes mellitus type 2 (DM2) patients have higher EAT volumes, it has been suggested that EAT may play a role in promoting CAD in these patients. The aim of this study was to examine the association between EAT and CAD in DM2, impaired fasting glucose (IFG) and control patients presenting with stable chest pain.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.