The cineless catheterization laboratory.
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Cardiac Catheterization↗
Biomedical subjects
J H Reiber
Publications and source records attributed to J H Reiber.
Automated extraction, labelling and analysis of the coronary vasculature from arteriograms.
For clinical decision-making and documentation purposes we have developed techniques to extract, label and analyze the coronary vasculature from arteriograms in an automated, quantitative manner. Advanced image processing techniques were applied to extract and analyze the vasculatures from non-subtracted arteriograms while artificial intelligence techniques were employed to assign anatomical labels. Lumen diameters of 11 phantom vessels were assessed with an accuracy of 0.27 +/- 0.19 mm (dtrue = 0.45 + 0.92dmeasured; r > 0.99) and 0.21 +/- 0.15 mm (dtrue = 0.42 + 0.91dmeasured; r > 0.99), from cine and digital images, respectively. We collected a total of 15 routinely acquired cine-arteriograms showing 74 vessel segments with 18 stenoses (severity larger than 30% assessed quantitatively), and 53 digital arteriograms showing 236 vessel segments with 69 stenoses. From the cine arteriograms we extracted 64 (86%) of the vessel segments without manual correction and 196 (83%) from the digital arteriograms. Repeated analysis (3 times) of the arteriograms by the same operator resulted in a standard deviation of the mean segment diameters (precision) of 0.064 mm for the cine-images and 0.020 mm for the digital images, while the standard deviations in the measurement of the minimal luminal diameter of the observed stenoses were 0.020 mm and 0.019 mm, respectively. The LAD artery, the septal and diagonal branches were correctly identified automatically in 86% of the segments. From these evaluations we conclude that our automated approach provides reliable tools for the assessment of multi-vessel disease, both in an off- and on-line environment.
Cineangiography↗
A new approach for the quantification of complex lesion morphology: the gradient field transform; basic principles and validation results.
OBJECTIVES: This report describes the basic principles and the results from clinical evaluation studies of a new algorithm that has been designed specifically for the quantification of complex coronary lesions. BACKGROUND: Currently used edge detection algorithms in quantitative coronary arteriography, such as the minimum cost algorithm, are limited in the precise quantification of complex coronary lesions characterized by abruptly changing shapes of the obstruction. METHODS: The new algorithm, the gradient field transform, is not limited in its search directions and incorporates the directional information of the arterial boundaries. To evaluate its accuracy and precision, 11 tubular phantoms (sizes 0.6 to 5.0 mm), were analyzed. Second, angiographic images of 12 copper phantoms with U-shaped obstructions were analyzed by both the gradient field transform and the minimum cost algorithm. Third, 25 coronary artery segments with irregularly shaped obstructions were selected from 19 routinely acquired angiograms. RESULTS: The plexiglass phantom study demonstrated an accuracy and precision of -0.004 and 0.114 mm, respectively. The U-shaped copper phantoms showed that the gradient field transform performed very well for short, severe obstructions, whereas the minimum cost algorithm severely overestimated the minimal lumen diameter. From the coronary angiograms, the intraobserver variability in the minimal lumen diameter was found to be 0.14 mm for the gradient field transform and 0.20 mm for the minimum cost algorithm. CONCLUSIONS: The new gradient field transform eliminates the limitations of the currently used edge detection algorithms in quantitative coronary arteriography and is therefore particularly suitable for the quantification of complex coronary artery lesions.
Algorithms↗
Magnetic resonance imaging during dobutamine stress for detection and localization of coronary artery disease. Quantitative wall motion analysis using a modification of the centerline method.
BACKGROUND: Quantitative measurement of wall motion is essential to assess objectively the functional significance of coronary artery disease. We developed a quantitative wall thickening analysis on stress magnetic resonance images. This study was designed to assess the clinical value of magnetic resonance imaging (MRI) during dobutamine stress for detection and localization of myocardial ischemia in patients with suspected coronary artery disease. METHODS AND RESULTS: Thirty-nine consecutive patients with clinically suspected coronary artery disease referred for coronary arteriography and 10 normal volunteers underwent gradient-echo MRI at rest and during peak dobutamine stress (infusion rate, 20 micrograms.kg-1.min-1). MRI was performed in the short-axis plane at four adjacent levels. Display in a cine loop provided a qualitative impression of regional wall motion (cine MRI). A modification of the centerline method was applied for quantitative wall motion analysis by means of calculation of percent systolic wall thickening. Short-axis cine MRI images were analyzed at 100 equally spaced chords constructed perpendicular to a centerline drawn midway between the end-diastolic and end-systolic contours. Dobutamine MRI was considered positive for coronary artery disease if the percent systolic wall thickening of more than four adjacent chords was < 2 SD below the mean values obtained from the normal volunteers. The overall sensitivity of dobutamine MRI for the detection of significant coronary artery disease (diameter stenosis > or = 50%) was 91% (30 of 33), specificity was 80% (5 of 6), and accuracy was 90% (35 of 39). The sensitivity for identifying one-vessel disease was 88% (15 of 17), for two-vessel disease 91% (10 of 11), and for three-vessel disease 100% (5 of 5). The sensitivity for detection of individual coronary artery lesions was 75% for the left anterior descending coronary artery, 87% for the right coronary artery, and 63% for the left circumflex coronary artery. CONCLUSIONS: Dobutamine MRI clearly identifies wall motion abnormalities by quantitative analysis using a modification of the centerline method. Dobutamine MRI is an accurate method for detection and localization of myocardial ischemia and may emerge as a new noninvasive approach for evaluation of patients with known or suspected coronary artery disease.
Adult↗
Relation of plasma coagulation factor VII and fibrinogen to carotid artery intima-media thickness.
Plasma clotting factor VII and plasma fibrinogen have been claimed as independent risk factors for occlusive cardiovascular disease. The aim of this study was to investigate whether these coagulation parameters affect early atherosclerosis, additional to their possible effect on arterial thrombosis. We used high-resolution quantitative ultrasonography to measure carotid intima-media thickness in 121 healthy volunteers, aged 18 to 56 years. It has previously been demonstrated that an increased artery wall thickness is seen in advanced atherosclerosis. To validate our methodology for relatively young individuals, we assessed the association of intima-media thickness with the risk-factor status of our subjects, by including classical cardiovascular risk factors, e.g. age, sex, serum cholesterol, smoking habits and blood pressure. Thereafter, we studied the effect of factor VII and fibrinogen plasma levels on carotid intima-media thickness, as well as that of polymorphisms of the factor VII and fibrinogen genes. All classical risk factors except smoking and family history were associated with intima-media thickness. When adjusted for by multivariate linear regression analysis, age, blood pressure and cholesterol appeared to be independent determinants of intima-media thickness. Factor VII and fibrinogen levels showed no association in multivariate analysis with intima-media thickness. We conclude that artery wall thickness measurement by ultrasound is a useful tool to investigate the role of clotting factors in early atherosclerosis. Factor VII and fibrinogen levels in young and middle-aged volunteers have no association with early artherosclerotic vessel wall changes.
Adult↗
Coronary arteriosclerotic lesions in type I diabetic patients eligible for combined renal-pancreatic transplantation.
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Adult↗
A comparison of immediate coronary angioplasty with intravenous streptokinase in acute myocardial infarction.
BACKGROUND: Despite the widespread use of intravenous thrombolytic therapy and of immediate percutaneous transluminal coronary angioplasty for the treatment of acute myocardial infarction, randomized comparisons of the two approaches to reperfusion are lacking. We report the results of a prospective, randomized trial comparing immediate coronary angioplasty (without previous thrombolytic therapy) with intravenous streptokinase treatment. METHODS: A total of 142 patients with acute myocardial infarction were randomly assigned to receive one of the two treatments. The left ventricular ejection fraction was measured by radionuclide scanning before hospital discharge. Quantitative coronary angiography was performed to assess the degree of residual stenosis in the infarct-related arteries. RESULTS: A total of 72 patients were assigned to receive streptokinase and 70 patients to undergo immediate angioplasty. Angioplasty was technically successful in 64 of the 65 patients who underwent the procedure. Infarction recurred in nine patients assigned to receive streptokinase, but in none of those assigned to receive angioplasty (P = 0.003). Fourteen patients in the streptokinase group had unstable angina after their infarction, but only four in the angioplasty group (P = 0.02). The mean (+/- SD) left ventricular ejection fraction as measured before discharge was 45 +/- 12 percent in the streptokinase group and 51 +/- 11 percent in the angioplasty group (P = 0.004). The infarct-related artery was patent in 68 percent of the patients in the streptokinase group and 91 percent of those in the angioplasty group (P = 0.001). Quantitative coronary angiography revealed stenosis of 36 +/- 20 percent of the luminal diameter in the angioplasty group, as compared with 76 +/- 19 percent in the streptokinase group (P < 0.001). CONCLUSIONS: Immediate angioplasty after acute myocardial infarction was associated with a higher rate of patency of the infarct-related artery, a less severe residual stenotic lesion, better left ventricular function, and less recurrent myocardial ischemia and infarction than was intravenous streptokinase.
Angioplasty, Balloon, Coronary↗
Accuracy and precision of quantitative digital coronary arteriography: observer-, short-, and medium-term variabilities.
Coronary arteriograms are increasingly acquired and stored in digital format, which allows instantaneous review of the pictorial data during the cardiac catheterization procedure. To support the angiographer in choosing the optimal sizes of the recanalization devices and studying the efficacy of the recanalization procedures, we have developed a new analytical software package (Automated Coronary Analysis = ACA) on the Philips DCI (-SX) digital cardiac imaging system. The ACA-package allows the objective and reproducible assessment of the morphologic and functional severity of coronary obstructions. Required user interaction is limited to the definition of the start and end points of the coronary segment to be analyzed. Automated contour detection is based on the use of first and second derivative functions along scanlines perpendicular to the automatically computed vessel pathline in the first iteration and perpendicular to the initial contours in the second iteration. These derivative functions have been modified based on the line spread function of the X-ray imaging chain, which is of particular importance for the accurate measurement of small vessel sizes. Phantom studies have indeed demonstrated that vessel sizes down to 0.66 mm can be measured accurately and reproducibly. Inter- and intraobserver variability studies have demonstrated a variability in the obstruction diameter of 0.11 mm and 0.10 mm, respectively, and in the percent diameter stenosis of 5.64% and 3.18%, respectively. These variability studies have been extended to short-term studies with repeated acquisition in the same angiographic views after 5 min and to medium-term studies with repeated acquisition in the initial angiographic views at the end of the catheterization procedures. With these standardized repeated acquisition and analysis procedures, the variabilities in the obstruction diameters increased to 0.19 and 0.18 mm, respectively, and remained below 6% in the percent diameter stenosis (5.61% and 5.28%, respectively). With an analysis time of approximately 15 sec on the DCI-SX, an efficient tool is now available in the catheterization laboratory for the objective and reproducible assessment of vessel dimensions and changes therein as a result of recanalization procedures.
Coronary Angiography↗
Quantitative angiographic follow-up studies on the development of coronary artery disease: which coronary segments should be analyzed? Experience from INTACT.
Angiographic follow-up studies on the evolution of coronary artery disease are of increasing relevance. It has still to be evaluated which coronary segments are predominantly involved in the process of atherosclerosis and, thus, should be preferably included in the analysis. Therefore, the correlation of progression and regression of coronary disease with the diameter and location (proximal, mid or distal) of coronary segments was investigated from the data of the INTACT-study, in which 25 different coronary segments were defined including anatomic variants of rather distal segments. In 348 patients with coronary artery disease, standardized coronary angiograms were repeated within 3 years and were quantitatively analyzed (CAAS). In 1063 coronary stenoses (% diameter stenosis > 20%) compared from both angiograms, progression and regression were not influenced by diameter nor location of arterial segments. In the follow-up angiograms, the number of new lesions (stenoses and occlusions) per coronary segment differed with regard to segment diameter (> 3 mm: 64/1125 (6%); 2-3 mm: 139/1967 (7%); < 2 mm: 44/1756 (2%); p < 0.001) and location of segments (proximal: 86/1285 (7%); mid: 84/1193 (7%); distal: 77/2370 (3%); p < 0.001). Out of 77 distal new lesions, only 25 (32%) were found in segments < 2 mm in diameter. Since the absolute number of new lesions was high in distal coronary segments, but low in segments with diameters < 2 mm, angiographic follow-up studies should analyze coronary segments at any location, but may neglect segments with diameters smaller than 2 mm.
Coronary Angiography↗
Left ventricular wall motion analysis in patients with acute myocardial infarction using magnetic resonance imaging.
Dynamic magnetic resonance (MR) imaging of the left ventricle was performed in 13 patients with acute myocardial infarction and in 11 healthy volunteers. Visual assessment of cine MR video loops correctly located the infarction of 12 of 13 patients. Quantitative analysis of absolute and relative wall thickening, area ejection fraction, and radial shortening fraction accurately distinguished hearts with and without infarction (p < .001). This distinction could also be made using the number of segments with decreased and the number of segments with decreased + increased wall motion (p < .001). Localization of the infarction by quantitative MR methods was limited, probably due to relative low temporal resolution. Combined evaluation of qualitative and quantitative MR imaging data provides useful information on wall motion dynamics after acute myocardial infarction.
Female↗
In-vivo validation of on-line and off-line geometric coronary measurements using insertion of stenosis phantoms in porcine coronary arteries.
Geometric coronary artery measurements with the Phillips Digital Cardiac Imaging System (DCI) and the Cardiovascular Angiography Analysis System (CAAS) were validated using percutaneous insertion of radiolucent stenosis phantoms in swine coronary arteries. Angiographic visualization of the stenosis lumens (phi 0.5, 0.7, 1.0, 1.4, 1.9 mm) was simultaneously recorded on DCI and cinefilm. The acquisition systems were calibrated by either the diameter of the guiding catheter (catheter CAL) or the isocenter method (isocenter CAL). Minimal luminal diameters (MLD) obtained with CAAS and DCI on 20 corresponding cineframes were compared with the true phantom diameters (PD). The accuracy of MLD measurements with the CAAS using isocenter CAL was -0.07mm, the precision 0.21 mm (r = 0.91; y = 0.30 + 0.79x; SEE = 0.19), with catheter CAL the accuracy was 0.09 mm, the precision 0.23 mm (r = 0.89; y = 0.19 + 0.74x; SEE = 0.19). The accuracy of MLD measurements using the DCI with isocenter CAL was 0.08 mm, the precision 0.15 min (r = 0.96; y = 0.08 + 0.86x; SEE = 0.14), with catheter CAL the accuracy was 0.18 mm, the precision 0.21 mm (r = 0.92; y = 0.09 + 0.76x; SEE = 0.17). DCI underestimated PD with isocenter CAL (p less than 0.05) and with catheter CAL (p less than 0.001). MLD can be measured with high accuracy, both applying on-line digital as well as off-line cineangiographic analysis. The results of digital measurements demonstrate high reliability of the new digital software package.
Animals↗
Angiographic assessment of dimensions of 6F and 7F Mallinckrodt Softouch coronary contrast catheters from digital and cine arteriograms.
Coronary contrast catheters are almost exclusively used for calibration purposes in quantitative coronary arteriography. In this study we have assessed the suitability of new 6F and 7F Mallinckrodt nylon catheter with Softouch tip with improved imaging specifications for such calibration purposes both from digital and cinefilm images using new analytical QCA-software packages (Philips DCI/ACA and Medis CMS). The average signed differences between the angiographically measured dimensions at 100% contrast fillings and acquired at 3 different kV-levels (60, 75 and 90 kV) were -3.3% and 0.6% for the 6F and 7F catheter tips, respectively as measured with the ACA-package on digital images, and -0.4% and 2.1%, respectively, as measured with the CMS-system on cinefilm images. The pooled standard deviations were 0.102 mm and 0.107 mm for the 6F and 7F catheter tips, respectively, as measured with the ACA-package, and 0.080 mm and 0.083 mm, as measured with the CMS-system. The deviations for the nylon shafts were much larger. It became also clear that neither the filling of the catheters, nor the kV-level used, had any appreciable effect on the measurement accuracy for the Softouch tips, which facilitates the frame selection in QCA-studies. From these data it can be concluded that the nontapering parts of the 6F and 7F Mallinckrodt Softouch tips are very well suitable for QCA calibration purposes, but that the nylon shafts are not.
Calibration↗
Exercise echocardiography and single photon emission computed tomography in patients with left anterior descending coronary artery stenosis.
To compare the diagnostic value of exercise echocardiography and perfusion single photon emission computed tomography (SPECT) in the detection of the presence and the severity of coronary artery disease, we studied 21 patients with isolated stenosis of different degree of the left anterior descending artery. Both echocardiography and SPECT were performed in conjunction with the same symptom-limited bicycle exercise test. Positivity of the test was based on the presence of exercise-induced wall motion abnormalities and transient perfusion defects, respectively. For both tests, an 'ischemic' score was derived, as index of extent and severity of myocardial ischemia. Coronary arteriography was evaluated by caliper. The agreement between exercise echocardiography and SPECT for the presence of coronary artery disease was 90%; the discordance was due to two patients with positive echocardiography and negative SPECT. A good correlation between ischemic wall motion and perfusion score indices was found (r = 0.78, p less than 0.0001. Moreover, the percent diameter stenosis was well correlated with both ischemic indices (r = 0.75, p less than 0.0001; r = 0.67, p less than 0.001, respectively). In patients with a positive test, the mean value of ischemic wall motion score index was higher in patients with a diameter stenosis greater than or equal to 70% than in patients with a diameter stenosis less than 70% (0.59 +/- 0.19 vs 0.29 +/- 0.12, p less than 0.01); a similar trend was found for ischemic perfusion score index (0.51 +/- 0.35 vs 0.27 +/- 0.12, ns).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Edge detection versus densitometry in the quantitative assessment of stenosis phantoms: an in vivo comparison in porcine coronary arteries.
The aim of this study was the in vivo validation and comparison of the geometric and densitometric technique of a computer-assisted automatic quantitative angiographic system (CAAS system). In six Landrace Yorkshire pigs (45 to 55 kg), precision-drilled phantoms with a circular lumen of 0.5, 0.7, 1.0, 1.4, and 1.9 mm were percutaneously introduced into the left anterior descending or left circumflex coronary artery. Twenty-eight coronary angiograms obtained with the phantom in a wedged intracoronary position could be quantitatively analyzed. Minimal lumen diameter, minimal cross-sectional area, percent diameter stenosis, and cross-sectional area stenosis were automatically measured with both the geometric and densitometric technique and were compared with the known phantom dimensions. When minimal lumen diameter was measured using the geometric approach, a nonsignificant underestimation of the phantom size was observed, with a mean difference of -0.06 +/- 0.14 mm. The larger mean difference observed with videodensitometry (-0.11 +/- 0.20 mm) was the result of the failure of the technique to differentiate the low lumen videodensities of two phantoms of smaller size (0.5 and 0.7 mm) from a dense background. Percent cross-sectional area stenosis measured with the two techniques showed a good correlation with the corresponding phantom measurements (mean difference between percent cross-sectional area stenosis calculated from the quantitative angiographic measurements and the corresponding phantom dimensions was equal to 2 +/- 6% for both techniques, correlation coefficient = 0.93 with both techniques, SEE = 5% with the geometric technique and 6% with the densitometric approach).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Exercise echocardiography versus thallium-201 SPECT for assessing patients before and after PTCA.
This study was designed (1) to assess the relationship between stress exercise echocardiography (echo) and 201-Tl single photon emission computed tomography (SPECT) applied simultaneously in 23 patients who were candidates to percutaneous transluminal coronary angioplasty (PTCA), (2) to assess the relationship between the development of exercise-induced wall motion abnormalities, transient perfusion defects and the severity of quantitatively assessed coronary stenoses and (3) to compare the functional improvement after PTCA by exercise echo and SPECT. Before PTCA there was an agreement of 78% between stress echo (new wall motion abnormalities) and SPECT (transient perfusion defects) results. All patients with a percentage diameter stenosis greater than 70% had a positive echo and SPECT, while they were both negative if the percentage diameter stenosis was less than 50%. In 19 patients re-studied 4 weeks after PTCA, an ischaemic response at stress echo was found in two of the 13 patients who had a positive stress echo test before PTCA, and SPECT was still positive in three of the 10 patients who had a positive SPECT study before PTCA. Echo and SPECT were concordant in 17/19 cases. It is concluded that exercise echo and 201-Tl SPECT are useful non-invasive tools for the functional assessment of patients before and after PTCA, and that they provide highly concordant results.
Aged↗
Edge detection versus densitometry for assessing coronary stenting quantitatively.
The optimal method used to analyze quantitatively the immediate angiographic results of coronary stenting in the coronary arteries has not been studied. Accordingly, minimal luminal cross-sectional area was determined by 2 methods, edge detection and densitometry, in 19 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) and then coronary stent implantation for symptomatic coronary stenoses. The correlation coefficient, 0.73 before angioplasty, decreased to 0.59 after coronary angioplasty and then increased to 0.83 after stent implantation. The mean differences between edge detection and densitometric determinations of minimal luminal cross-sectional area were 0.31 +/- 0.51 mm2 before PTCA, -0.38 +/- 1.22 mm2 after angioplasty and 0.35 +/- 0.79 mm2 after coronary stenting. It is concluded that, although the correlation and variability in the measurement of minimal luminal cross-sectional area between edge detection and densitometry deteriorate after PTCA, they are improved after stenting, probably because of smoothing of the vessel contours by the stent and remodeling of the stented segment into a more circular configuration. Therefore, in the stented coronary artery, edge detection and densitometry are equally acceptable methods of analysis.
Absorptiometry, Photon↗
Do stents interfere with the densitometric assessment of a coronary artery lesion?
This in vitro study was designed to assess the contribution of three currently investigated coronary stents to the densitometric measurement of a known stenosis contained within two different sized plexiglass phantoms. These studies were performed at two concentrations of the contrast agent iopamidol (50 and 100%). The calculated minimal luminal cross-sectional area values in the control phantom ranged from 0-18% higher than the theoretical values. Insertion of a stainless steel stent (Wallstent, Schneider, Zürich or Palmaz-Schatz, Johnson and Johnson, Warren, NJ) resulted in further minor increases (less than or equal to 8% in the calculated minimal luminal cross-sectional area, except in the smaller phantom filled with 50% contrast medium. The Wiktor (tantalum) stent (Medtronic, Minneapolis, MN) had the largest impact of the three stents depending on the concentration of iopamidol (100% contrast medium: 9-13% values above control; 50% contrast medium; 23-56% higher). We conclude that although densitometry may overestimate the minimal luminal cross-sectional area in stented vessels, this effect is usually minor with stainless steel stents. However, tantalum-containing stents may result in serious overestimation of lesion area, particularly if contrast is diluted or the vessel is not well filled.
Coronary Angiography↗
Comparative study of three different approaches on the estimation of the lung-heart ratio in thallium 201 scintigrams in relation to the extent of coronary artery disease and left ventricular function.
Uptake of thallium 201 (201Tl) in the lungs has been proposed as a measure of left ventricular dysfunction with exercise. To study this hypothesis, we compared the lung/-heart (LH) ratio assessed from anterior planar images (ANT-P), from anterior images obtained during single photon emission tomography (SPET) acquisition (ANT-T) and from short-axis tomographic cross-sections (CS) in early post-exercise thallium 201 scintigrams. The study population consisted of 54 prepercutaneous transluminal coronary angioplasty (PTCA) studies (82% with single-vessel disease), 50 post-PTCA studies, 33 pre-coronary artery bypass surgery (CABG) studies (71% with three-vessel disease), 30 post-CABG studies and 30 patients with a left ventricular dysfunction (LVD) due to an acute myocardial infarction; 18 individuals with a low likelihood of coronary artery disease (CAD) served as a control group. The results demonstrated that, on average, the LH ratios obtained from ANT-P and ANT-T were not significantly different for all study groups; these ratios increased significantly with ischaemia and with LVD relative to non-ischaemic situations. However, the LH ratios in CS did not show a relation with ischaemia nor with LVD and differed significantly from the LH-ratios assessed from the anterior approaches. Each of the three approaches (ANT-P, ANT-T, CS) was characterized by large overlaps of LH ratios for the different study groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Angioplasty, Balloon, Coronary↗