Biomedical subjects

Andreas Knez

Publications and source records attributed to Andreas Knez.

At least 19 recordsLinked to original sources

PubMed2007

ECG-gated 64-MDCT angiography in the differential diagnosis of acute chest pain.

OBJECTIVE: The most important differential diagnoses of acute chest pain include myocardial infarction, aortic dissection, and pulmonary embolism. The purpose of this study was to evaluate the diagnostic value of an ECG-gated 64-MDCT angiography protocol for simultaneous assessment of the pulmonary arteries, coronary arteries, and aorta within a single breath-hold. SUBJECTS AND METHODS: In 55 patients with acute chest pain, ECG-gated CT angiography was performed with a CT system in which 64 slices per gantry rotation were acquired. Density measurement and visual assessment of motion artifacts were performed to evaluate image quality. CT findings were correlated with results of laboratory tests and clinical follow-up. For 20 patients, two independent blinded reviewers compared findings on CT angiography with those on X-ray coronary angiography. RESULTS: Adequate contrast enhancement of the pulmonary vessels, coronary arteries, and aorta was achieved in all cases. Regarding image quality of the coronary arteries, there was minor blurring in seven patients, and in one examination the images did not provide enough information for diagnosis. The average image quality rating was 1.2 on a scale in which 1 indicated no artifacts; 2, minor motion artifacts; and 3, image insufficient for diagnosis. The cause of chest pain was correctly identified with MDCT in 37 patients. The diagnoses included pulmonary embolism (n = 10), coronary stenosis (n = 9), and aortic dissection (n = 1). In four patients, additional diagnoses were found with other examinations. CONCLUSION: With current techniques, ECG-gated CT angiography of the entire chest has very good image quality. The protocol proved helpful in the differential diagnosis of acute chest pain.

Acute Disease↗

PubMed2006

Visual and automatic grading of coronary artery stenoses with 64-slice CT angiography in reference to invasive angiography.

The aim of this study was to assess the performance of a software tool for quantitative coronary artery analysis of computed tomography coronary angiography (CT-QCA) in comparison with invasive coronary angiography with quantitative analysis (CAG-QCA) as standard of reference. Two radiologists reviewed the CT angiography data sets (Siemens Sensation 64) of 25 patients, grading coronary artery stenoses visually and with a software tool (Circulation, Siemens). Twenty-three data sets with sufficient image quality were included in the final analysis. CAG revealed a total of 30 wall irregularities and 28 stenoses, of which 17 were graded as moderate and nine as hemodynamically significant. CT-QCA showed a better agreement to CAG-QCA, with a systematic overestimation of the degree of stenosis of 6.1% and limits of agreement of +36.1% and -23.9; the correlation coefficient was 0.82 (p < 0.0001). Using CT-QCA, sensitivity, specificity, and positive and negative predictive value were 89%, 100%, 89%, and 100%, respectively, for significant area stenoses greater than 75%. The positive predictive value for the visual assessment amounted to 53%. Interobserver variability between CT-QCA and visual assessment showed a kappa value of 0.72. In conclusion, software-supported CT-QCA makes it possible to quantify significant coronary artery stenoses automatically, with good agreement to CAG-QCA.

Contrast Media↗

PubMed2006

Multislice computed tomography for determination of coronary artery disease in a symptomatic patient population.

BACKGROUND: Multislice computed tomography (MSCT) has started to replace Electron beam CT for quantitation of coronary artery calcium. However no study has evaluated the diagnostic accuracy of MSCT for prediction of coronary artery disease (CAD) in a symptomatic patient population using the volume score. METHODS AND RESULTS: 1347 symptomatic subjects (male = 803, mean age = 62 years) with suspected CAD underwent MSCT studies 1 +/- 2 days before the coronary angiogram. The Agatston (ACS) and Volumetric calcium score (VCS) were calculated using a proprietary workstation. Statistical analyses included the Pearson's correlation coefficient and the nonparametric Mann-Whitney U-test to compare the calcium score in different age groups and between men and women. Sensitivity, specificity and predictive accuracy were calculated for different calcium thresholds for prediction of CAD. ROC curve analyses were used to establish relations between the coronary calcium score and presence or absence of CAD. In 720 (53%) subjects (male = 419) angiography revealed a minimal lumen diameter stenosis greater than 50%. Patients with significant CAD had significantly higher total calcium score values than patients without CAD (P = 0.001). ACS and VCS demonstrate a close correlation for the whole study group, r = 0.99. The overall sensitivity of any calcium to predict stenosis was 99%, specificity = 32%. Exclusion of calcium was highly accurate for exclusion of CAD in subjects older than 50 years (predictive accuracy = 98%). An absolute cutoff >100 and an age and sex specific threshold (score over 75th percentile) were identified as the cutoff levels with the highest sensitivities (86-89%) and lowest false positive rates (20-22%). ROC analyses revealed MSCT calcium scanning as a good clinical test which can be performed with similar accuracy in all age groups with an area under the curve of 0.84. CONCLUSION: Determination of coronary calcium with MSCT is an accurate imaging modality for prediction of significant CAD in a patient population with intermediate likelihood of CAD. Exclusion of any calcium provided strong evidence that patients older than 50 years did not have obstructive CAD. ACS and VCS show an equivalent diagnostic accuracy.

Area Under Curve↗

PubMed2006

Sixty-four slice spiral CT angiography does not predict the functional relevance of coronary artery stenoses in patients with stable angina.

PURPOSE: The aim of this study was to evaluate spiral multidetector computed tomography (MDCT) angiography using 64-slice technique in the detection of functionally relevant coronary artery stenoses (CAS). METHODS: Thirty-eight patients (62+/-11 years, 28 men) with stable angina (26 with suspected and 12 with known coronary artery disease) were investigated using 64-slice MDCT angiography and gated myocardial perfusion SPECT (gated SPECT); a subgroup of 30 patients had additional invasive coronary angiography (ICA). Stenoses with luminal narrowing of >or=50% were defined as "significant" in MDCT angiography and ICA. MDCT angiography was compared with gated SPECT and the combination of gated SPECT plus ICA with respect to the detection of functionally relevant CAS. RESULTS: The sensitivity, specificity and negative and positive predictive values of MDCT angiography in detecting reversible perfusion defects on gated SPECT were 63%, 80%, 94% and 32%, respectively, in vessel-based analysis and 71%, 62%, 72% and 60%, respectively, in patient-based analysis. If only reversible perfusion defects on gated SPECT with CAS >or=50% on ICA were considered, the sensitivity, specificity and negative and positive predictive values were, respectively, 85%, 79%, 98% and 33% for vessel-based analysis and 85%, 59%, 83% and 61% for patient-based analysis. CONCLUSION: Sixty-four slice MDCT angiography failed to predict the functional relevance of CAS, but had a high negative predictive value in the exclusion of functionally relevant CAS in symptomatic patients.

Angina Pectoris↗

PubMed2006

Dual-source CT cardiac imaging: initial experience.

The relation of heart rate and image quality in the depiction of coronary arteries, heart valves and myocardium was assessed on a dual-source computed tomography system (DSCT). Coronary CT angiography was performed on a DSCT (Somatom Definition, Siemens) with high concentration contrast media (Iopromide, Ultravist 370, Schering) in 24 patients with heart rates between 44 and 92 beats per minute. Images were reconstructed over the whole cardiac cycle in 10% steps. Two readers independently assessed the image quality with regard to the diagnostic evaluation of right and left coronary artery, heart valves and left ventricular myocardium for the assessment of vessel wall changes, coronary stenoses, valve morphology and function and ventricular function on a three point grading scale. The image quality ratings at the optimal reconstruction interval were 1.24+/-0.42 for the right and 1.09+/-0.27 for the left coronary artery. A reconstruction of diagnostic systolic and diastolic images is possible for a wide range of heart rates, allowing also a functional evaluation of valves and myocardium. Dual-source CT offers very robust diagnostic image quality in a wide range of heart rates. The high temporal resolution now also makes a functional evaluation of the heart valves and myocardium possible.

Algorithms↗

PubMed2006

Preventing cardiac allograft vasculopathy: long-term beneficial effects of mycophenolate mofetil.

BACKGROUND: The impact of long-term mycophenolate mofetil (MMF) treatment on the development of cardiac allograft vasculopathy (CAV) after heart transplantation is an area of much recent interest. This study analyzed the effects of various immunosuppressive combinations, including cyclosporine (CsA), azathioprine (Aza), tacrolimus (Tac) and MMF, on the time of onset, extent and progression of CAV. METHODS: Two hundred seventy-three consecutive heart transplant recipients (mean age: 51.2 +/- 12.2 years; mean follow-up: 6.8 +/- 1.9 years) were examined by coronary angiography on a yearly basis between 1995 and 2003. The extent of CAV was evaluated using a scoring system based on the severity of vessel stenosis. The onset of CAV was analyzed using Kaplan-Meier estimates and the log rank test for four treatment combinations, CsA/Aza (n = 47, 17.2%), CsA/MMF (n = 26, 9.5%), Tac/Aza (n = 62, 22.7%) and Tac/MMF (n = 138, 50.5%), and for the primary and the secondary immunosuppressants alone. RESULTS: The rate of freedom from CAV at 5 years was 47% with CsA/Aza, 66% with CsA/MMF, 60% with Tac/Aza and 70% with Tac/MMF. After 5 years, the Tac/MMF group showed a significantly lower incidence of CAV than the CsA/Aza group (log rank 7.58, p = 0.0059). CsA (n = 73) was compared with Tac (n = 200) and MMF (n = 164) with Aza (n = 109): the rate of freedom from CAV was 51.2% in CsA patients vs 66.1% in Tac patients (log rank 5.7, p = 0.017), and 54.6% in Aza patients vs 67% in MMF patients (log rank 4.36, p = 0.037). Multivariate Cox regression analysis revealed that MMF decreased the incidence of CAV significantly (p = 0.041). In this patient cohort, Tac or CsA medication was not an independent risk factor for incidence of CAV nor for decreased survival. CONCLUSIONS: The choice of immunosuppression has an impact on the incidence of CAV. In terms of prevention of CAV, MMF is superior to Aza in either combination. A trend toward improved survival in MMF patients was noted. The lower number of rejection episodes in the MMF groups may have contributed to these results.

Adolescent↗

PubMed2006

Accuracy of 64-slice computed tomography to classify and quantify plaque volumes in the proximal coronary system: a comparative study using intravascular ultrasound.

OBJECTIVES: We evaluated the accuracy of a new 64-slice computed tomography (CT) scanner, compared with intravascular ultrasound, to visualize atherosclerosis in the proximal coronary system. BACKGROUND: Noninvasive determination of plaque composition and plaque burden may be important to improve risk stratification. METHODS: In 20 patients, a 64-slice CT scan (Sensation 64, Siemens Medical Solutions, Forchheim, Germany) and an intravascular ultrasound investigation of vessels without stenosis >50% was performed. Diagnostic image quality with 64-slice CT was obtained in 36 vessels in 19 patients. RESULTS: In these vessels, which were divided in 3-mm sections, 64-slice CT enabled a correct detection of plaque in 54 of 65 (83%) sections containing noncalcified plaques, 50 of 53 (94%) sections containing mixed plaques, and 41 of 43 (95%) sections containing calcified plaques. In 192 of 204 (94%) sections, atherosclerotic lesions were excluded correctly. In addition, 64-slice CT enabled the visualization of 7 of 10 (70%) sections revealing a lipid pool and could identify a spotty calcification pattern in 27 of 30 (90%) sections. The correlation coefficient to determine plaque volumes per vessel was r2 = 0.69 (p < 0.001) with an underestimation of mixed and noncalcified plaque volumes (p < 0.03) and a trend to overestimate calcified plaque volumes by 64-slice CT. The interobserver variability to determine plaque volumes was 37%. Interobserver agreement to identify atherosclerotic sections was good (Cohen's kappa coefficient = 0.75). CONCLUSIONS: We conclude that 64-slice CT reveals encouraging results to noninvasively detect different types of coronary plaques located in the proximal coronary system. The ability to determine plaque burden currently is hampered by mainly an insufficient reproducibility.

Coronary Angiography↗

PubMed2006

Assessment of coronary artery stent patency and restenosis using 64-slice computed tomography.

RATIONALE AND OBJECTIVES: Restenosis remains a major limitation of coronary catheter-based stent placement. Therefore, a reliable noninvasive diagnostic method for the evaluation of stented coronary arteries would be highly desirable. Our aim was to evaluate the diagnostic accuracy of high-resolution 64-slice computed tomography (64SCT) in a pilot study for the assessment of the lumen of coronary artery stents. MATERIALS AND METHODS: Twenty-five patients underwent 64SCT of the coronary arteries and quantitative x-ray coronary angiography (QCA) after coronary artery stent placement. 64SCT coronary angiography was performed with the following parameters: spatial resolution = 0.4 x 0.4 x 0.4 mm; temporal resolution = 83-165 milliseconds; contrast agent = 80 mL at a flow rate of 5 mL/second; retrospective electrocardiogram gating. The 64SCT scans were evaluated for image quality and for the presence of significant in-stent and peri-stent (proximal and distal) stenoses. Determinations were made of the sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values (PPV and NPV) of 64SCT for the detection or exclusion of stenoses. RESULTS: A total of 46 stents were evaluated, of which 45 (98%) were of diagnostic image quality. Significant in-stent restenosis or occlusion was detected on QCA in 8/45 cases (>/=50% stenosis = 6; occlusion = 2). The sensitivity, specificity, accuracy, PPV, and NPV of 64SCT for the detection of significant in-stent disease was 75%, 92%, 89%, 67%, and 94%, respectively. Both occluded coronary artery stents were correctly identified. The sensitivity, specificity, and accuracy values of 64SCT for the detection of significant proximal peri-stent stenoses were 75%, 95%, and 93%, respectively, whereas the values for detection of significant distal peri-stent stenoses were 67%, 85%, and 84%, respectively. CONCLUSION: The high spatial and temporal resolution of 64SCT may permit improved assessment of stent occlusion and peri-stent disease, although detection of in-stent stenosis remains difficult.

Adult↗

PubMed2006

Image quality, motion artifacts, and reconstruction timing of 64-slice coronary computed tomography angiography with 0.33-second rotation speed.

OBJECTIVES: We sought to evaluate the impact of patients' heart rate (HR) on coronary CTA image quality (IQ) and motion artifacts using a 64-slice scanner with 0.33/360 degrees rotation. MATERIALS AND METHODS: Coronary CTA data sets of 32 patients (HR 65 bpm to 75 bpm, n = 7) examined on a 64-slice scanner (Sensation 64, Siemens Medical Solutions, Forchheim, Germany) with 0.33s/360 degrees gantry rotation speed were analyzed. All patients had suspicion of coronary artery disease. Data acquisition was performed using 64 x 0.6-mm collimation, and contrast enhancement was provided by injection of 80 mL of iopromide (5 mL/s + NaCl). Images were reconstructed throughout the RR interval using half-scan and dual-segment reconstruction. IQ was rated by 2 observers using a 3-point scale from excellent (1) to nondiagnostic (3) for coronary segments. Quality was correlated to the HR, time point of optimal IQ analyzed, and the benefit of dual-segment reconstruction evaluated. RESULTS: Overall mean IQ was 1.31 +/- 0.32 for all HR, with IQ being 1.08 +/- 0.12 for HR 65 bpm 75 bpm (P = 0.0003). Dual-segment reconstruction did not significantly improve IQ in any HR group (P = NS). Mean IQ was significantly better for LAD than for RCA (P < 0.0001) and LCX (P < 0.01). A total of 3.5% (11/318) of coronary artery segments were rated nondiagnostic by at least one reader based on motion artifacts. Although in HR < 65 bpm, the best IQ was predominately in diastole (93%), in HR > 75 bpm, the best IQ shifted to systole in most cases (86%). CONCLUSIONS: Temporal resolution at 0.33-second rotation allows for diagnostic IQ within a wide range of HR using half-scan reconstruction. With increasing HR the time point of best IQ shifts from mid-diastole to systole.

Adult↗

PubMed2006

Contrast bolus optimization for cardiac 16-slice computed tomography: comparison of contrast medium formulations containing 300 and 400 milligrams of iodine per milliliter.

OBJECTIVES: The aims of our study were to compare contrast injection protocols with contrast media containing 300 and 400 mg iodine per milliliter for optimal contrast enhancement in cardiac multidector row computed tomography (CT) and to evaluate the correlation of test bolus curve parameters with the final contrast density of the main bolus. MATERIALS AND METHODS: Sixty patients with known or suspected coronary artery disease were included in a prospective double-blind study. Patients were randomized to 2 groups. Group 1 received 83 mL of a contrast medium (CM) containing 300 mg of iodine (Iomeron 300, Bracco Imaging SpA, Milan, Italy) at a flow rate of 3.3 mL/s, whereas group 2 received 63 mL of the same agent containing 400 mg of iodine (Iomeron 400) at a flow rate of 2.5 mL/s. The test bolus volumes were 20 mL and 15 mL, respectively. Imaging was performed using a 16-slice CT system (16DCT; Somatom Sensation 16, Siemens Medical Solutions, Forchheim, Germany). Contrast densities (Hounsfield Units [HU]) were determined in the cardiac chambers and in the main coronary arteries. The peak density and area under the curve of the test bolus were calculated for each patient. RESULTS: The mean contrast densities of the coronary arteries were 259.1 +/- 46.7 HU for group 1 and 251.6 +/- 51.0 HU, for group 2. No noteworthy differences between groups were noted for density measurements in the cardiac chambers or for the ratio of right-to-left ventricle density. Whereas a positive correlation was noted for both groups between the area under the curve of the test bolus and the mean density of the main bolus, a positive correlation between peak density of the test bolus and mean density of the main bolus was noted only for group 1. CONCLUSION: Equivalent homogenous enhancement of the ventricular cavities and coronary arteries to that obtained using a CM with standard iodine concentration (Iomeron 300) can be achieved with lower overall volumes of administered CM and reduced injection flow rates when a CM with high iodine concentration (Iomeron 400) is used.

Adult↗

PubMed2006

Clinical value of MDCT in the diagnosis of coronary artery disease in patients with a low pretest likelihood of significant disease.

OBJECTIVE: The aim of this study was to evaluate the clinical value of MDCT in the diagnosis of coronary artery disease in a population having a low pretest likelihood of significant disease. SUBJECTS AND METHODS: Sixty-four patients with suspected coronary artery disease and a low pretest likelihood of significant disease according to the criteria of the American Heart Association underwent both MDCT of the heart and quantitative conventional coronary angiography (QCA). MDCT examinations were performed on a 16-MDCT scanner. CT data sets were evaluated on a per-patient basis and a per-segment basis and were classified as indicating no disease, nonsignificant disease (stenoses </= 50%), or significant disease (stenoses > 50%). Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of 16-MDCT in the detection or exclusion of significant and nonsignificant coronary artery disease were evaluated on both per-patient and per-segment bases. RESULTS: Regarding the success rate of 16-MDCT, 94% (60/64) of patients and 92% (388/420) of vessel segments were of sufficient quality for diagnosis. In the remaining 60 patients evaluated, QCA revealed significant coronary artery disease, nonsignificant disease, and no disease in 8.3% (5/60), 75.0% (45/60), and 16.7% (10/60) of cases, respectively, on a per-patient basis, and in 1.3% (5/388), 23.2% (90/388), and 75.5% (293/388) of cases, respectively, on a per-segment basis. The sensitivity, specificity, NPV, and PPV of 16-MDCT for the detection of significant coronary artery disease were 80.0%, 94.5%, 98.1%, and 57.1%, respectively, on a per-patient basis, and 80.0%, 99.2%, 99.7%, and 57.1% on a per-segment basis. CONCLUSION: In a population having a low pretest likelihood of significant coronary artery disease, 16-MDCT shows a moderate to high sensitivity and high NPV for the detection or exclusion of significant disease, but has a somewhat reduced PPV compared with QCA.

Adult↗

PubMed2006

Accuracy of 64-MDCT in the diagnosis of ischemic heart disease.

OBJECTIVE: The aim of this study was to evaluate the potential clinical value of a new generation of 64-MDCT systems with that of invasive coronary angiography in the diagnosis of coronary artery disease (CAD). SUBJECTS AND METHODS: Seventy-two consecutive patients with known or suspected CAD underwent both 64-MDCT and quantitative coronary angiography (QCA). A CT system with acquisition of 64 slices per gantry rotation was used with a spatial resolution of 0.4 x 0.4 x 0.4 mm and a gantry rotation time of 330 milliseconds. Sensitivity, specificity, and diagnostic accuracy of 64-MDCT in the detection or exclusion of CAD were evaluated on both a per patient and a per segment basis. RESULTS: Sixty-eight of 72 coronary CT angiograms (CTAs) (94%) were of diagnostic image quality. QCA showed significant CAD (i.e., one or more stenoses in > 50%) in 57% (39/68) and nonsignificant disease or healthy CTAs in 43% (29/68) of the patients. Sensitivity, specificity, and the negative predictive value (NPV) of 64-MDCT per patient were 97%, 79%, and 96%, respectively. Per segment, 923 of 1,020 coronary artery segments were assessable (90%). For the detection of stenoses of more than 50% and more than 75% per segment, 64-MDCT showed a sensitivity of 82% and 86%, respectively. Per segment, specificity and NPV were as high as 95% and 97%, respectively. CONCLUSION: In clinical routine, coronary CTA will primarily be used for risk stratification on a per patient basis. In the present study, coronary 64-MDCT showed a high diagnostic accuracy on both per patient and per segment analyses.

Adult↗

PubMed2005

Hemodynamic and vascular effects of ventricular sourcing by stent-based ventricle to coronary artery bypass in patients with multivessel disease undergoing coronary artery bypass surgery.

BACKGROUND: The hemodynamic and vascular effects of ventricular sourcing by a stent-based (VSTENT, Percardia) left ventricle-to-coronary artery bypass were studied in a patient subgroup of the European multicenter ADVANTAGE study (ADjunctive treatment with the VCAB/VSTENT myocardial implANT system in coronary Artery bypass Graft patiEnts). METHODS AND RESULTS: Twelve patients who underwent VSTENT implantation in addition to coronary artery bypass surgery were studied up to 12 months after the procedure. The VSTENT was implanted distal to a hemodynamically relevant coronary artery stenosis. Coronary flow velocity was assessed at rest and during dobutamine stress. Intraoperative VSTENT implantation was successful in 11 of 12 patients. Early postoperative angiograms showed patent VSTENT in 8 of 11 patients, with predominantly systolic flow distal to the VSTENT. Coronary flow velocity reserve induced by dobutamine stress was 1.7+/-0.1 (P=0.006). VSTENT patency at 2- to 6-month follow-up was present in 5 of 11 patients, with concomitant VSTENT stenosis in 4 of those 5. In all patients, coronary flow velocity increased 3- to 4-fold proximal to the VSTENT, which was associated with a moderate degree of arterial remodeling. Except for target vessel reintervention (n=5), no other major adverse events were observed in 11 of 12 patients. One patient died on the second postoperative day, though the cause was probably not related to the VSTENT implantation. CONCLUSIONS: VSTENT implantation seems to be safe in the mid-term follow-up and leads to a predominantly systolic coronary flow pattern in the vessel supplied by the VSTENT, with a flow reserve similar or close to that seen with conventional bypass. VSTENT patency rate, however, was unacceptably low at 3- to 6-month follow-up and needs to be improved.

Aged↗

PubMed2005

Quantification of obstructive and nonobstructive coronary lesions by 64-slice computed tomography: a comparative study with quantitative coronary angiography and intravascular ultrasound.

OBJECTIVES: The aim of the present study was to determine the diagnostic accuracy of 64-slice computed tomography (CT) to identify and quantify atherosclerotic coronary lesions in comparison with catheter-based angiography and intravascular ultrasound (IVUS). BACKGROUND: Currently, the ability of multislice CT to quantify the degree of coronary artery stenosis and dimensions of coronary plaques has not been evaluated. METHODS: We included 59 patients scheduled for coronary angiography due to stable angina pectoris. A contrast-enhanced 64-slice CT (Senation 64, Siemens Medical Solutions, Forchheim, Germany) was performed before the invasive angiogram. In a subset of 18 patients, IVUS of 32 vessels was part of the catheterization procedure. RESULTS: In 55 of 59 patients, 64-slice CT enabled the visualization of the entire coronary tree with diagnostic image quality (American Heart Association 15-segment model). The overall correlation between the degree of stenosis detected by quantitative coronary angiography compared with 64-slice CT was r = 0.54. Sensitivity for the detection of stenosis <50%, stenosis >50%, and stenosis >75% was 79%, 73%, and 80%, respectively, and specificity was 97%. In comparison with IVUS, 46 of 55 (84%) lesions were identified correctly. The mean plaque areas and the percentage of vessel obstruction measured by IVUS and 64-slice CT were 8.1 mm2 versus 7.3 mm2 (p < 0.03, r = 0.73) and 50.4% versus 41.1% (p < 0.001, r = 0.61), respectively. CONCLUSIONS: Contrast-enhanced 64-slice CT is a clinically robust modality that allows the identification of proximal coronary lesions with excellent accuracy. Measurements of plaque and lumen areas derived by CT correlated well with IVUS. A major limitation is the insufficient ability of CT to exactly quantify the degree of stenosis.

Aged↗

PubMed2005

Visualising noncalcified coronary plaques by CT.

Due to a rapid improvement of the new generation submillimetre multislice CT-technology noninvasive tomographic imaging of the coronary vessel wall has become reality. First clinical studies have shown the ability in particular of 16-slice CT to determine plaque burden, plaque composition and compensatory vessel-wall remodelling. These novel findings already constitute an important step forward to assess coronary atherosclerosis noninvasively in a detailed manner which opens promising new opportunities for a better understanding and riskstratification of coronary atherosclerosis. Current limitations, mainly the insufficient accuracy to detect small lesions in distal coronary segments, might be overcome by improved spatial and temporal resolution of the new generation scanners operating with 64 and more detectors.

Contrast Media↗

PubMed2005

Early clinical results with a magnetic connector for distal coronary artery anastomoses.

PURPOSE: The main goals in the development of an anastomotic device are to reduce the invasiveness of the procedure and to improve graft patency. We analyze our preliminary clinical experience with the Ventrica magnetic vascular positioner (MVP) series 6000 system. DESCRIPTION: Eighteen distal anastomoses were performed in 11 patients using the MVP. EVALUATION: The target artery for MVP was left anterior descending in 9 patients, a marginal branch in 4, the first diagonal branch in 3, and the right coronary artery in 2. Graft material was the left internal thoracic artery in 9 patients, saphenous vein in 6, the right internal thoracic artery in 2, and the radial artery in 1 case. Fifteen anastomoses were performed in an end-to-side and 3 in a side-to-side fashion. Predischarge angiography was performed in 10 of 11 patients. There was a patent MVP anastomosis in all patients. CONCLUSIONS: Distal anastomoses using the MVP were performed successfully in all patients. The procedure is simple. Short-term patency is excellent. Further randomized trials are necessary to determine long-term safety and patency.

Adult↗

PubMed2005

Comparison of spiral multidetector CT angiography and myocardial perfusion imaging in the noninvasive detection of functionally relevant coronary artery lesions: first clinical experiences.

UNLABELLED: Compared with conventional coronary angiography, spiral multidetector CT (MDCT) angiography has delivered promising accuracy in the detection and validation of coronary lesions. Myocardial perfusion imaging (MPI) using SPECT is an established method for noninvasively assessing the functional significance of coronary stenoses and delivers valuable information for risk stratification. This retrospective analysis compared the accuracies of MDCT angiography and MPI in the detection of hemodynamically relevant lesions of the coronary arteries. METHODS: Twenty-five patients with suspected or known coronary artery disease were studied. Electrocardiographically gated MPI and 16-MDCT angiography were performed. Myocardial perfusion images were analyzed by 2 experienced observers, and reversible and fixed perfusion defects were detected and allocated to their corresponding coronary vessels. For the evaluation of MDCT angiography, image quality was determined, and lesions > or = 50% and luminal narrowing < 50% were visually assessed and characterized by 2 independent observers unaware of the results of MPI. RESULTS: Ninety-nine coronary vessels were analyzed, and the quality of MDCT angiography images was assessed for 330 coronary segments. Coronary artery diameter was interpretable for 231 (70%) of 330 segments, whereas in 99 (30%) of 330 segments, vessel diameter could not be evaluated because of heavy calcifications, blurring, motion artifacts, or intracoronary stents. MDCT angiography detected stenoses > or = 50% in 15 of 100 coronary arteries. Eight (53%) of 15 stenoses > or = 50% showed reversible or fixed perfusion defects in the corresponding myocardial areas on MPI. Sensitivity, specificity, and negative and positive predictive values were 100%, 87%, 100%, and 29%, respectively, for the ability of MDCT angiography to detect reversible perfusion defects in the corresponding myocardial areas. CONCLUSION: MDCT angiography detected myocardial ischemia, as defined by reversible perfusion defects on MPI, with a positive predictive value of 29% in a nonselected study cohort. Compared with MPI alone, MDCT angiography added important morphologic information, but MPI remains mandatory for evaluating the functional relevance of coronary artery lesions.

Coronary Angiography↗

PubMed2004

CT measurement of coronary calcium mass: impact on global cardiac risk assessment.

Coronary calcium mass percentiles can be derived from electron beam CT as well as from multidetector-row CT of all manufacturers. Coronary calcium mass may serve as a more individualized substitute for age for cardiac risk stratification. The aim was to investigate the potential impact of CT coronary calcium mass quantification on cardiac risk stratification using an adjusted Framingham score. Standardized coronary calcium mass was determined by multidetector-row CT in a total of 1,473 patients (1,038 male, 435 female). The impact on risk stratification of replacing the traditional Framingham age point score by a point score based on calcium mass relative to age was tested. Any coronary calcium found in males in the age group of 20-34 years and females in the age group of 20-59 years results in an increase of the Framingham score by 9 and 4-7 points, respectively. Only in males 65 years of age and older, none or minimal amounts of coronary calcium decrease the Framingham score by three points. The coronary calcium mass and age-related scoring system may have impact on the reassignment of patients with an intermediate Framingham risk to a lower or higher risk group.

Adult↗