Biomedical subjects

André Plass

Publications and source records attributed to André Plass.

7 recordsLinked to original sources

PubMed2006

Accuracy of dual-source CT coronary angiography: First experience in a high pre-test probability population without heart rate control.

The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1+/-11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14+/-9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter > or =1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3+/-3.9 kg/m2 (range 22.4-36.3 kg/m2), mean heart rate during CT was 70.3+/-14.2 bpm (range 47-102 bpm), and mean Agatston score was 821+/-904 (range 0-3,110). Image quality was diagnostic (scores 1-3) in 98.6% (414/420) of segments (mean image quality score 1.68+/-0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control.

Adult↗

PubMed2006

Noninvasive coronary angiography with 64-section CT: effect of average heart rate and heart rate variability on image quality.

PURPOSE: To evaluate prospectively the effect of average heart rate and heart rate variability on image quality at 64-section computed tomographic (CT) coronary angiography. MATERIALS AND METHODS: The study protocol had local ethics committee approval; written informed consent was obtained. There were 125 patients (45 women, 80 men; mean age, 59.9 years +/- 12.9 [standard deviation]; 79 receiving beta-blockers) who underwent 64-section CT coronary angiography with retrospective electrocardiographic gating. Data sets were reconstructed in 5% steps from 20% to 80% of R-R interval. Heart rate variability was calculated as 1 standard deviation from mean rate during scanning. Two observers rated image quality of each coronary segment at least 1.5-mm diameter (1 = no motion artifacts, 5 = not evaluative). Repeated analysis of variance measurements were performed to evaluate quantitative parameters. Pearson correlation analysis was performed to compare image quality in each patient with average heart rate and heart rate variability. RESULTS: Average heart rate was 63.3 beats per minute +/- 13.1, with variability of 3.2 beats per minute +/- 2.1. Diagnostic image quality (score < or = 3) was attained in 1821 of 1836 segments at the best reconstruction interval. There was no correlation between mean heart rate and image quality for all segments of the right coronary and left anterior descending arteries, but there was a significant correlation for left circumflex artery (r = 0.33, P < .05). Heart rate variability was correlated with image quality overall (r = 0.75, P < .001) and for each coronary artery. Heart rate was less variable and image quality was better (P < .05) in patients receiving beta-blockers. Best image quality was obtained in diastole with heart rate less than 80 beats per minute and in systole with faster heart rate. CONCLUSION: Coronary angiography with 64-section CT provides diagnostic image quality within a wide range of heart rates. Reducing average heart rate and heart rate variability is beneficial for reducing artifacts.

Adult↗

PubMed2006

Coronary artery imaging with 64-slice computed tomography from cardiac surgical perspective.

INTRODUCTION: 64-Slice computed tomography (CT) has been introduced with high expectations. This study illustrates the value of 64-slice CT for the diagnosis of significant coronary artery stenoses when images are analysed by cardiovascular surgeons. METHODS: Fifty patients (39 males, 11 females) underwent invasive coronary angiography and 64-slice CT. In these patients, 40 had coronary artery disease and 10 patients had valvular disease. Evaluation of right coronary artery (RCA), left main (LM), left anterior descending artery (LAD), diagonal branch 1 (D1), circumflex branch (CX), and 1st marginal branch was performed by two cardiovascular surgeons. All vessels with a diameter >/=1.5 mm were analysed and a lumen restriction of >50% was considered a significant stenosis. CT image quality was classified as excellent, reduced but still diagnostic, and not assessable. Invasive coronary angiography was taken as gold standard for calculations of diagnostic accuracy. RESULTS: Mean heart rate during CT scan was 65+/-11 beats per minute (bpm). Image quality of 92% (506/550) of all segments was rated as excellent, 5% (27/550) were rated as being of reduced quality but still diagnostic, and 3% (17/550) were considered not assessable. The sensitivity for diagnosing a significant stenosis with CT when including all reliably evaluated segments was 93% (106/114), specificity was 97% (381/392), positive predictive value was 91% (106/117), and negative predictive value was 98% (381/389). CONCLUSION: 64-Slice CT provides a high diagnostic accuracy in assessing significant coronary artery stenosis. Nevertheless, still exist some disadvantages such as strong vessel wall calcifications reducing the reliability for image interpretation. At the moment, 64-slice CT should be used as a complementary imaging modality to invasive coronary angiography.

Aged↗

PubMed2006

Sixteen-channel multidetector row computed tomography versus coronary angiography in a surgical view.

BACKGROUND: Invasive coronary angiography (ICA) is the gold standard for the diagnosis of coronary artery disease and also for imaging procedures for preoperative planning of coronary artery bypass grafting (CABG). Sixteen-multidetector row computed tomography (MDCT) represents an alternative depiction of coronary vessels. METHODS: Preoperative exams included ICA and MDCT in 50 patients. Two blinded surgical readers independently investigated both diagnostic modalities regarding location, severity, and morphology of the stenoses. The right coronary artery, left anterior descending branch, and circumflex branch--each divided in 3 sections--and the left main artery with a diameter (3) 1.5 mm were rated in both procedures, and the percentage of complete evaluations by MDCT was assessed. RESULTS: Heart rate was 72 +/- 8 bpm. Forty-six percent of patients received a complete MDCT evaluation, and 54% received an incomplete MDCT evaluation. In 62% of these incompletely examined patients, 1 branch was not completely analyzable, in 31% 2 branches; and in 7% all 3 branches. In total, 9% of all segments were incompletely assessed. Investigators detected coronary stenoses in complete evaluations with a sensitivity of 94% and a specificity of 95%. Positive predictive value was 87% and negative predictive value was 98%. Plaque classification in soft and hard plaques was possible. CONCLUSION: Sixteen-MDCT is not a viable alternative diagnostic tool at present. However, although the percentage of incomplete evaluated patients is more then 50%, only 9% of all segments were incompletely assessable. If this technology can be further improved, especially its software, it will become a valid diagnostic tool for coronary artery disease.

Coronary Angiography↗

PubMed2005

Mitral regurgitation: quantification with 16-detector row CT--initial experience.

PURPOSE: To prospectively determine if retrospectively electrocardiographic (ECG)-gated multi-detector row computed tomography (CT) with a 16-detector row CT scanner can depict mitral regurgitation and enable quantification of the severity of the disease. MATERIALS AND METHODS: The study had institutional review board approval, and patients gave informed consent. Nineteen patients with mitral regurgitation (10 men, nine women; mean age, 66 years +/- 9 [standard deviation]; range, 41-83 years) and 25 patients without mitral regurgitation (14 men, 11 women; mean age, 68 years +/- 9; range, 43-83 years) as determined with transesophageal color Doppler echocardiography and ventriculography underwent retrospectively ECG-gated 16-detector row CT. Twenty CT data sets covering the entire mitral valve apparatus were reconstructed in 5% steps of the R-R interval for each patient, and data analysis was performed with four-dimensional software. Using planimetry, two readers measured in consensus the area of the regurgitant orifice during systole. These measurements were compared with semiquantitative data from transesophageal echocardiography and ventriculography by using Spearman rank order correlation coefficients. RESULTS: In the 25 patients without mitral regurgitation, no regurgitant orifice during systole could be detected with multi-detector row CT. In the 19 patients with mitral regurgitation, a regurgitant orifice could be visualized in all cases. The mean regurgitant orifice area at CT-45 mm(2) +/- 34 (range, 10-148 mm(2))-correlated significantly with the results at transesophageal echocardiography (r = 0.807, P < .001) and ventriculography (r = 0.922, P < .001). CONCLUSION: Planimetric measurements of the regurgitant orifice area at retrospectively ECG-gated 16-detector row CT enable quantification of mitral regurgitation.

Adult↗

PubMed2005

Accuracy of MSCT coronary angiography with 64-slice technology: first experience.

AIMS: The aim of our study was to investigate the accuracy of 64-slice computed tomography (CT) for assessing haemodynamically significant stenoses of coronary arteries. METHODS AND RESULTS: CT angiography was performed in 67 patients (50 male, 17 female; mean age 60.1+/-10.5 years) with suspected coronary artery disease and compared with invasive coronary angiography. All vessels > or =1.5 mm were considered for the assessment of significant coronary artery stenosis (diameter reduction >50%). Forty-seven patients were identified as having significant coronary stenoses on invasive angiography with 18% (176/1005) affected segments. None of the coronary segments needed to be excluded from analysis. CT correctly identified all 20 patients having no significant stenosis on invasive angiography. Overall sensitivity for classifying stenoses was 94%, specificity was 97%, positive predictive value was 87%, and negative predictive value was 99%. CONCLUSION: Sixty-four-slice CT provides a high diagnostic accuracy in assessing coronary artery stenoses.

Adult↗

PubMed2005

Dynamic cine mode imaging of the normal aortic valve using 16-channel multidetector row computed tomography.

BACKGROUND: We investigated the feasibility and image quality of dynamic cine-mode imaging of the normal aortic valve using multidetector row computed tomography (MDCT). MATERIALS AND METHODS: We acquired contrast-enhanced retrospectively echocardiography (ECG)-gated cardiac MDCT datasets of 35 patients (mean age, 62 years; range, 53-77) who received a transoesophageal echocardiography (TOE) precedent to cardiac bypass graft surgery. Twenty data sets in 5% steps of the R-R interval were reconstructed, and data analysis was performed using a 4D software. Read-out of the MDCT data was performed in parallel and perpendicular planes, similar to TOE standard planes, by 2 independent, blinded readers using a 4-point Likert scale (best score: 4) for the following parameters: image quality of the aortic valve components, contrast media enhancement, contrast media inflow related artifacts, and ECG gating-related artifacts. The aortic valve area (AVA) was measured planimetrically and was compared between TOE and MDCT. RESULTS: The best phase for assessing the open valve using MDCT was at 5% and the closed valve at 65% of the cardiac cycle. The mean image quality scores for cine-mode MDCT ranged between 3.26 and 3.75, with inter-reader agreements ranging between good (kappa = 0.723) and excellent (kappa = 1.00). They did not differ significantly from TOE scores for assessment of the closed and open valve. In transitional phases (close-to-open and open-to-close) TOE performed significantly better when compared with static MDCT images, whereas no significant difference was present between cine-mode presentation of MDCT and TOE. Planimetric AVA measurements correlated significantly between TOE and MDCT (Pearson correlation coefficient, r = 0.96; P < 0.0001). Contrast media inflow-related and ECG gating related artifacts were rated as slightly compromising (scores 3.24 and 3.21). CONCLUSION: Retrospectively ECG-gated MDCT offers a noninvasive, accurate, and dynamic imaging method for quantitative and qualitative evaluation of the normal aortic valve allowing determination of morphology and function throughout the cardiac cycle. Further studies regarding assessment of diseased valves are necessary.

Aged↗