[Experimental study of the influence on pacemakers of X-rays from angiocardiography equipment].

We performed an experimental study of the influence on pacemakers (PM) of X-rays from the angiocardiography equipment. (1) We used one PM of DDD mode in this study. (2) The PM was irradiated under two exposure levels: one the standard dose and the other the maximum dose in the angiocardiography study situation. (3) We set the pacing lead wires to the bilateral atria and ventricles in Irnich's human body model. (4) We set two irradiation fields, one with a lead block on the PM and the other without the lead block. The result showed that when the PM was included in the irradiation field and the exposure level was of the maximum dose, the influence of irradiation on the PM was that of level 2 as classified by a research report by the Ministry of Internal Affairs and Communications. The absorbed dose of the PM was 93.4 mGy under these conditions. We confirmed that radiation dose does not affect a pacemaker with pacing lead wire. However, it acts on the generator of the PM owing to the direct photoelectric effect. When there were many dose rates (or total radiation dose), an obstacle occurred.

Survey on performance assessment of cardiac angiography systems.

Advances in imaging technology have facilitated the development of increasingly complex interventional cardiac equipment. Consequently, there is a need for definitive equipment requirements. The aim of the study is to assess the performances of different cardiac angiographic systems. A questionnaire was sent to centres participating in SENTINEL Project to collect dosimetry data (typical entrance dose rate in fluoroscopy and imaging mode), image quality evaluations (low and high contrast resolutions) and KAP calibration factors. Results from this survey could contribute to the explanation of patient dose variability in angiographic cardiac procedures and to derive reference levels for cardiac angiographic equipment performance parameters.

Volumetric analysis of the right and left ventricle in a porcine heart model: comparison of three-dimensional echocardiography, magnetic resonance imaging and angiocardiography.

UNLABELLED: Three-dimensional echocardiography and magnetic resonance imaging allow the volumetric analysis of ventricular volumes independent of geometric assumptions. The aim of the study was to compare these methods and the common angiocardiography in a cardiac model of known volume. METHODS/MATERIALS: Right and left ventricular (RV, LV-) volumes were measured in a specific animal model directly ('true volume') and with different imaging techniques. Three-dimensional echocardiography (3D-Echo) and magnetic resonance imaging (MRI), both of which permit a volume estimation without necessitating geometric assumptions, and angiocardiographic volumetry which is based on the Simpson rule were used in this study. RESULTS: The best results were achieved with MRI (RV: r(2)=0.99, mean difference: -1. 9+/-3.3%; LV: difference r(2)=0.99,: 2.9+/-5.0%). Likewise, 3D-Echo showed a very good correlation with the true volumes (RV: r(2)=0.93, difference: 9.3+/-6.3%; LV r(2)=0.96, difference: 4.8+/-9.9%). The greatest deviations were observed during angiocardiographic volumetry (LV: r(2)=0.98; difference: 14.4+/-9.2%), particularly when measuring the right ventricle (RV: r(2)=0.82, difference: 57. 9+/-40.1%). Consequently, the direct comparison between 3D-Echo and the other methods yielded the best correspondence with MRI (RV: Bias: 3.7 ml, limits of agreement: 7.7 ml; LV: Bias: 3.7 ml, limits of agreement: 4.9 ml). In contrast, the differences between 3D-Echo and angiocardiography were marked (RV: Bias: 25.5 ml, limits of agreement: 11.1 ml; LV: Bias: 8.7 ml, limits of agreement: 13.2 ml). CONCLUSION: In a porcine cardiac model, 3D-Echo permits a relatively precise measurement of ventricular volumes with a slight under-estimation. MRI yielded the most precise volumetry, and the correlation between 3D-Echo and MRI was quite good. Particularly for the right ventricle, the angiocardiographic measurement was attached with the greatest error and thus appears ill-suited for the volumetry of geometrically more complex ventricles.

Radiographic detection of single-leg fracture in Björk-Shiley Convexo-Concave prosthetic valves: a phantom model study.

Cineradiography can identify patients with single-leg fractured Björk-Shiley Convexo-Concave valves, although little is known about the sensitivity and specificity of this technique. We evaluated three normal and six (0 microm gap) single-leg fractured Björk-Shiley valves that were placed in a working phantom model. Valves were randomly imaged a total of 33 times and duplicated into a 120-valve series with a 1:9 ratio of abnormal/normal valves. Six reviewers independently graded each valve and demonstrated markedly different rates of identifying the fractured valves. Average sensitivity at the grade that clinically results in valve explanation was 47%. Among the normal valves, a correct identification was made 96% (range 91% to 99%) of the time. Present radiographic technology may have significant difficulty in identifying true single-leg fracture in Björk-Shiley valves with limb separations that are common among clinically explanted valves.

[Individual archiving of digital angiocardiograms]. / Individuelles Archivieren von digitalen Angiokardiogrammen.

CD-R will be introduced internationally as a standardized individual archive and exchange medium allowing individual solutions for long-term archiving in a catheterization laboratory. The concept of digital archiving on two CD-R includes a long-term primary basic archive and a secondary one edited by intelligent (medical) data reduction (IDR). The basic archive is automatically composed by a background process consisting of unprocessed images or image series and is fundamental for further transfers, storage, presentations and additional studies. The digital working archive comprises a set of images and image series edited by IDR, as well as the results of morphometric studies as well as identification and documentation data. IDR is based upon the elimination of useless and redundant images series, documentation of coronary interventions on one single representative image and on the reduction of relevant images series and physiological data into an ECG-controlled representative cardiac cycle. IDR edits a redundancy-free set of 130 images (diagnostic study) or only 85 images of an interventional study. Two cardiologists and two cardiosurgeons independently studied 24 IDR-edited angiograms and the corresponding unedited digital angiograms and found no significant differences in the diagnostically relevant coronary morphology and left ventricular function. This study shows that an edited angiogram may not only serve for digital archiving but also form the basis for further evaluation or copies.

Radiologic history exhibit. Charles T. Dotter: a pioneering interventional radiologist.

This article briefly summarizes the work of Charles Dotter, a pioneer in interventional radiology. His enthusiasm, powers of observation, innovations, and aggressive pursuit of his ideas permitted achievement of many radiologic milestones.

Analytic isocenter calibration. A new approach for accurate x-ray gantries.

Isocenter calibration transforms cardiac structures in digitized biplane angiograms to absolute dimensions, calculating their radiological magnification and video transformation. Since a scaling device is not required, isocenter calibration yields to more accurate measurements than the widely used reference object calibration. Both isocenter methods reported so far, regarding geometrically inaccurate x-ray gantries, yield to different and complex computational formulas. Since these formulas are hard to understand, isocenter calibration is less widely used. To facilitate the implementation of the isocenter calibration, the basic formulas for accurate x-ray gantries are derived. Shifting virtually one x-ray system onto the other, basic isocenter calibration is derived geometrically in three simple steps. The radiological magnification of an object is illustrated as a ratio of planes. The calculation of all parameters entering the computations is demonstrated geometrically, by use of the isocenter of the x-ray gantry. The derivation gives a clear idea of isocenter calibration. It is simple to derive and facilitates the understanding of the error regarding developments. When geometrical inaccuracies vanish, all formulas become equivalent. However, even if the inaccuracies increase, all methods provide nearly identical results, indicating the robustness of isocenter calibration.

Improved left ventriculography with the new 5F helical-tip Halo catheter.

The purpose of this study was to evaluate the incidence of ventricular ectopy and catheter movement during left ventriculography with a new 5F halo angiographic catheter that has a unique helical-tip design unlike the design of standard 5F and 6F pigtail catheters. The pigtail catheter is presently preferred for left ventriculography, although its use is associated with a high incidence of ventricular ectopy, which often limits precise interpretation of data. In this study, 155 patients (in 145 unpaired and 10 paired studies) underwent left ventriculography during diagnostic cardiac catheterization. In the unpaired group, the 5F Halo catheter was used in 63 studies and standard 5F and 6F pigtail catheters in 40 and 42 studies, respectively. An additional 10 patients had two consecutive left ventriculograms with 5F Halo and pigtail catheters. Ventriculograms were performed with the same technique in the 30-degree right anterior oblique projection. The left ventricle was divided into a basal zone, midzone, and apical zone. Catheter movement within the ventricle was scored as significant if there was at least one zone change. Ventricular ectopy was quantified by a simultaneous electrocardiographic recording during contrast injection. There were no significant differences in the left ventricular systolic or end-diastolic pressures, left ventricular score, or diagnostic quality of the ventriculograms between the 5F Halo catheter group and the 5F and 6F pigtail catheter groups. Mean ventricular ectopy with the 5F Halo catheter was significantly less (0.9 +/- 1.4 ventricular premature beats [VPBs]) than with the 5F pigtail catheter (2.3 +/- 2.5 VPBs, p < 0.001) or the 6F pigtail catheter (2.9 +/- 2.9 VPBs, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Three-dimensional radiologic device as a new diagnostic aid in angiocardiography].

Angiography with 180 degrees arc was performed using a rapidly rotating stereoradiographic device and a single injection of contrast medium. Duration of rotation of the X-ray tube through 180 degrees was 2.25 sec. The angiograms displayed in a rotating manner were three-dimensional with depth information. Every adjacent angiograms were obtained by the rapidly rotating X-ray tube at slightly different angles and positions, resulting in paired stereo images. The angiograms can be displayed on side-by-side monitors and viewed stereoscopically with a stereoviewer. Rotating images were displayed at 30 frames/sec (60 fields/sec) and were viewed in a fluorographic manner. To apply the data to angiocardiography the following procedures were required: 1) the start of rotation of the X-ray tube was synchronized with the R wave of the EKG, 2) suspension of respiration, and 3) the subject's upper extremities were immobilized at his head. To obtain left atrial angiograms the following steps were taken: 1) the circulation time from the pulmonary artery to the left atrium was estimated by injecting 15 ml contrast medium into the pulmonary artery under the fixed X-ray tube, then, 2) X-ray exposures of 20 fields/sec were obtained during 15 sec, and 3) left atrial arteriograms were taken by using the rotating X-ray tube referring to the circulation time. With this method, stenotic lesions of the coronary arteries and collateral pathways were easily observed simultaneously with morphological changes in a 180 degrees arc.(ABSTRACT TRUNCATED AT 250 WORDS)

[Coronarography using high-flow 5F catheters. Percutaneous technic using the femoral and brachial routes]. / Coronariografía con catéteres 5F de alto flujo. Técnica percutánea por vías femoral y braquial.

In order to validate 5F catheters for assessing ischemic heart disease either by the femoral and the right brachial approaches, we prospectively studied with these catheters 125 patients by means of left ventriculogram and coronary artery angiograms. Twenty-five patients were studied with pigtail and Amplatz catheters using the right brachial approach (group I) and 100 patients were studied by the femoral route with pigtail and Judkins catheters (group II). Results were compared to those obtained in a control group of 100 patients prospectively studied by the femoral route with 8F catheters (group III). The following parameters were analyzed: need to change the initially elected catheter diameter or/and artery approach; technical difficulty for obtaining left ventriculogram, left coronary artery, and right coronary artery angiograms; total time of X-ray exposure; quality image of left ventriculograms; incidence of arterial puncture related hematomas or total arterial occlusion; and duration of local compression after sheath removal. There were no differences between groups I and II except for the arterial compression time (p less than 0.0001), and the X-ray exposure time (p = 0.02); both were longer in patients studied by the brachial approach (group I). Whatever the route used, 5F showed a mild increased difficulty (brachial p = 0.001; femoral p = 0.01), and a mild decreased quality image for left coronary artery (brachial p = 0.006; femoral p less than 0.05). Among patients studied by the femoral route a reduction in mild hematomas (p less than 0.05) and in the arterial compression time (p less than 0.0001) were observed in those studied with 5F catheters.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intracoronary fracture of a guidewire tip in percutaneous coronary angioplasty]. / Rupture intracoronaire de l'extrémité d'un guide d'angioplastie coronaire percutanée.

The authors report a case of intracoronary rupture of the tip of a guidewire used for angioplasty. They discuss its mechanism and management. The hazards involved in re-using coronary dilatation material are underlined.

[Videometry and videodensitometry: possibilities within the scope of clinical angiocardiography]. / Videometrie und Videodensitometrie: Möglichkeiten im Rahmen der klinischen Angiokardiographie.

Videometry and videodensitometry was developed more than 20 years ago by the groups of E. H. Wood in Rochester, New York, USA and P. H. Heintzen in Kiel, West Germany. These techniques allow the extraction of quantitative parameters such as dimensions and volumes (videometry) and the concentration and distribution of contrast material (videodensitometry) from videoangiograms. Whereas videometric techniques have, in between, been implemented world-wide into clinical practice (e.g., for geometric measurement of heart chamber volume or the quantitative assessment of coronary morphology), videodensitometry has still been restricted to a small number of laboratories, mainly due to the technical requirements. Videodensitometry, however, offers an on-line frame-to-frame analysis of left and right ventricular volumes throughout the cardiac cycle, the measurement of valvular regurgitant fraction, the estimation of intracardiac shunts, as well as the measurement of blood flow and velocity in coronary arteries and the assessment of changes in myocardial perfusion due to interventions form clinical videoangiograms. Since the basic principles of these techniques can easily be applied to digital image processing, videodensitometry has gained new interest in a time of increasing distribution of digital cardiac imaging.