Conventional Ventriculography Research Articles

Global left ventricular function: assessment with dual-source CT versus conventional ventriculography in a porcine model

Objective — Cardiac computed tomography (CT) and conventional biplane ventriculography are established methods for the determination of ventricular function. Recently dual source CT was introduced for cardiac CT scanning providing a temporal resolution of 83ms independent of the patient’s heart rate.The purpose of this study was to assess the global left ventricular function using retrospectively ECG-gated dual source computed tomography (DSCT) in comparison to conventional ventriculography.Methods and results — Contrast-enhanced cardiac DSCT and conventional ventriculography were performed in 10 domestic pigs with an approximate weight of 60kg using standardized examination protocols under general anaesthesia. From manually drawn endocardial contours, LV end-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF) were calculated by means of dedicated analysis software separately for both examination modalities. LV functional parameters were analysed using Bland-Altman plots, Student t-test, and Pearson correlation coefficient. Left ESV and EDV determined with DSCT correlated well with conventional ventriculography results (ESV: r=0.86; EDV: r=0.72) with a good correlation also for SV (r=0.67).An only moderate correlation was found for EF (r=0.52). Student t-test showed a significant underestimation of SV and EF derived from DSCT in comparison to ventriculography.Conclusion — Retrospectively ECG-gated DSCT can accurately determine LV volumes in comparison to conventional ventriculography but provides lower SV and EF values; however, the correlation was only moderate.

Assessment of left ventricular volumes and function by cine-MR imaging depending on the investigator’s experience

To analyze the reproducibility of LV volumes calculated by cardiac magnetic resonance imaging (CMRI) and to compare them to those obtained by conventional ventriculography. A total of 30 patients with stable ischemic heart disease were prospectively included. Each underwent CMRI twice and ventriculography. Left ventricular end diastolic volume (EDV), end systolic volume (ESV) and LV ejection fraction (EF) were calculated by two radiologists at different level of experience. Intraobserver, interobserver and interstudy variabilities were assessed. The cut off values were: intraobserver variability (EDV, ESV, EF): 9.4 ml, 5.3 ml, 3.3% for well-trained radiologist; 13.1 ml, 7.5 ml, 4.1% for less-trained radiologist. interobserver variability: EDV: 11.7 and 10.4 ml; ESV: 7.0 and 6.6 ml; EF: 3.9 and 4.2%. interstudy variability (EDV, ESV, EF): 11.6 and 12.6 ml, 7.1 and 7.4 ml, 3.9 and 3.5%, for experienced and less-trained observers. Statistical differences were found between CMRI and ventriculography: CMRI underestimation of EDV and EF, overestimation of ESV. CMRI volumetric quantification of LV volumes and function is highly reproducible at different levels of experience, but not interchangeable with those obtained by ventriculography.

Multi-slice computer tomography of left ventricular function with automated analysis software in comparison with conventional ventriculography

Purpose To evaluate the accuracy of left ventricular volumetric and functional parameters from multi-slice computed tomography using automated analysis software, and to correlate results with those of invasive left ventriculography. Materials and methods In 145 consecutive patients (mean age, 61 years ± 12) known or suspected to have coronary artery disease, a 16-channel multi-slice computed tomography (Philips Mx8000 IDT 16) was performed using a standard technique. Using short-axis secondary multi-slice computed tomography reformations, we determined end-diastolic and end-systolic left ventricular volumes and ejection fraction with a commercially available analysis software capable of automated contour detection. Conventional left ventriculography was performed according to standard techniques within the following 24 h. Bland-Altman analysis was performed to calculate the limits of agreement and systematic errors between multi-slice computed tomography and conventional left ventriculography. Results As determined by computer tomography, mean end-systolic (53 ± 29 mL) left ventricular volumes had an acceptable correlation with conventional ventriculography (67 ± 50 mL; r = 0.74; p < 0.001) and mean end-diastolic (119 ± 33 mL) left ventricular volumes a poor correlation with conventional ventriculography measurements (154 ± 69 mL; r = 0.41). Left ventricular ejection fraction (57% ± 14 versus 55% ± 14 for conventional ventriculography; r = 0.79) showed a very good correlation ( p < 0.001). Bland-Altman analysis showed acceptable limits of agreement (±9.2% for ejection fraction) without systematic errors. Conclusion The use of a multi-slice computed tomography with an automatic calculation software has a good correlation with conventional ventriculography findings and could accurately assess left ventricular function, but should not be used for ventricular volumes, because of biased estimations.

Four-Dimensional Imaging of the Heart Based on Near-Isotropic MDCT Data Sets

Lawler LP, Ney D, Pannu HK, Fishman EK our-dimensional cardiac CT is a concept in evolution [1, 2]. In this paper, we define 4D cardiac CT as a processed study that assimilates a series of sequential, static, phase-specific, 3D volume helical data sets into a cine image that reflects the in vivo model of the 3D spatial information mapped to the sequential time and motion relationship of the cardiac cycle. It can be applied to derive morphologic and functional information, but it is distinct from existing tools, which deduce such information from static planar slices of end systole and end diastole alone. This technique will form an important facet of the comprehensive cardiac CT study. The initial relatively high-speed acquisition of electron beam CT (EBCT) [3] provided some of the earliest quantitative CT information on ventricular size and shape and on systolic function. However, this complex technology was never widely available, was limited to prospective gating, and is fast being replaced by the the more versatile mechanical CT where its acquisition parameters in terms of temporal resolution are rapidly approaching those of EBCT. Earlier work with single-detector helical scanning was able to produce animated 2D images of the heart with ventricular values that closely correlated with conventional ventriculography [4]. Materials and Methods Data Acquisition and Processing To generate a 4D data set, one must first acquire a density profile and positional information that characterize each voxel of the heart structure for a series of time points throughout the cardiac systolic and diastolic phases. The patient is scanned in a single breath-hold with simultaneous recording of the ECG signal. Current helical MDCT systems provide near-isotropic voxels from 0.75-mm detector systems (Sensation, Siemens Medical Solutions) giving 0.75to 1-mm slice collimation reconstructed at 50% overlap. Large detector arrays, fast gantry rotation, and segmental reconstruction contribute to a TR of 120–130 msec. Vascular lumen, endocardial surface, and chamber contrast resolution is achieved through a peripheral-venous upper-extremity power injection of 120 mL of nonionic iodinated contrast (Visipaque 320, Amersham Health) delivered at a rate of 3 mL/sec followed by a saline flush from a dual-head injector. Scanning acquisition begins 17 sec after the contrast administration. Unlike coronary CT angiography, which uses only diastolic data, 4D CT utilizes all data derived from irradiating the patient. Effective dose depends on heart rate but is approximately 7.0 mSv for a man and 10.2 mSv for a woman, with a CT dose index of 42.0 mGy. Axial planar data for 3D and 4D postprocessing are reconstructed from the raw data using retrospective gating, which defines a portion of the cardiac cycle as a percentage of the R-R interval. For 4D imaging, a contiguous sequence of nine or more separate “whole-heart” volumes, of equal duration intervals, is generated. These volumes represent the distinct phases (i.e., “time windows”) of cardiac motion (e.g., 10%, 20%, 30%, and so forth up to 90% of the R-R interval). This is a semiautomatic standard process of all cardiac software and is performed at the scanner. The user simply defines the percentage reconstruction desired, and the result is a series of separate stacks of axial images with each stack representing a particular period of the cardiac cycle. Within each time window, all voxels of the heart are represented. The total number of images may be more than 2,000 images, depending on the slice reconstruction used (0.75–1 mm). The data are sent to a 3D workstation that incorporates commercially available volume-rendering software and supports a work-in-progress version of 4D software.

Bestimmung linksventrikulärer Funktionsparameter mittels EKG-gesteuerter Mehrschicht-Computertomographie im Vergleich mit der invasiven Ventrikulographie

To evaluate the accuracy of left ventricular function using a multidetector CT (MDCT) with retrospective ECG-gating and to compare the results with conventional ventriculography. In 26 patients, retrospectively ECG-gated MDCT of the heart (Volume Zoom, Siemens, Germany) as well as conventional coronary angiography including ventriculography was performed to exclude or follow coronary artery disease. CT examination (120 KV, 400 mAs) was carried out with 4 x 1 mm collimation (500 ms gantry rotation time). For CT angiography, 150 ml of contrast media was injected intravenously at a flow rate of 4 ml/s. All data sets of the functional cardiac parameters were reconstructed in end-systolic and end-diastolic phase. End-systolic volume (ESV), end-diastolic volume (EDV) and ejection fraction (EF) were determined from multiplanar reformations orthogonally through the cardiac short axis and analyzed using special evaluation software (ARGUS, Siemens). The results were compared with ESV, EDV and EF obtained from invasive ventriculography. In all cases, a sufficient quality of the MDCT images was achieved. EDV (150.1 +/- 16.2 ml MDCT vs. 138.7 +/- 16.9 ml ventriculography; mean difference 11.4 +/- 12.7 ml; r = 0.51) had an acceptable correlation to conventional ventriculography, and ESV (58.1 +/- 14.6 ml vs. 50.2 +/- 13.4 ml; mean difference 7.9 +/- 8.8 ml; r = 0.81) and EF (60.9 +/- 13.6 % vs. 64.9 +/- 12.7 %; mean difference 4.0 +/- 6.2 %; r = 0.79) showed a good correlation. In comparison with invasive ventriculography, MDCT tended to overestimate significantly EDV (p = 0.008) and ESV (p = 0.003) and to underestimate EF (p = 0.001). MDCT of the heart with retrospective ECG-gating enables efficient estimation of left ventricular function, providing important additional information of non-invasive cardiac imaging using MDCT. However, EDV and EVS were significantly overestimated and EF was underestimated in MDCT compared to ventriculography.

Surgical control of akinesia in Parkinson's disease.

Posteroventral pallidotomy (PVP) was carried out in 86 patients with Parkinson's disease, who presented marked bradykinesia, freezing of gait and postural defect associated with rigidity and tremor in 82 patients (bradykinesia type), and similar gait and postural problems with minimum signs of rigidity and tremor in 4 (pure akinesia type). The stereotactic coordinates of Leksell's device were calculated from MRI and conventional ventriculography. The final target was defined by microelectrode techniques in the basal ganglia. The microrecording study revealed a very high background activity in the internal pallidum in patients of the bradykinetic type, however, a much lower pallidal activity in patients of the pure akinesia type. Fifty-eight patients underwent unilateral PVP, and 28 underwent bilateral surgery. Following PVP, rigidity tremor and poor reciprocal movements were significantly improved especially in the contralateral extremities. The most dramatic findings were the reversal of akinetic symptoms and wearing-off phenomena. The patients were followed up for 3-30 months (mean = 8) after surgery. Of the 82 bradykinesia type patients, good result were obtained in 48 (58%), fair results in 26 (32%), and minor improvement or no change in 8 (10%). In all the 4 patients of the pure akinesia type, recurrence of the akinetic symptoms occurred after a temporal improvement lasting a few days to 3 month after surgery. There was worst dysarthria in 3 patients, hemiparesis in 1 and partial motor aphasia in 1. The visual field problem was not complicated in any patients. These findings suggest that akinetic symptoms in PD are implicated in overactive pallidal outputs with putative GABAergic modulator by excessively inhibiting pedunculopontine nucleus activity (midbrain locomotor and posture regions) as well as thalamic activity. Partial interruption of the pallidal efferents eliminates the akinetic symptoms by disinhibitory effects on the target structures. The pathology of PD of the pure akinesia type is supposedly in the brainstem and should be excluded from indication of pallidotomy.

Quantitative Echocardiography, Part 2

Two-dimensional echocardiography is widely used for assessment of cardiac chamber size and function. A new method for real-time quantitative assessment of left ventricular systolic function using automatic boundary detection (ABD) has been developed based on principles of quantitative ultrasound backscatter imaging of the myocardium. The clinical accuracy of ABD for measurement of cardiac chamber areas and volumes has been validated against conventional two-dimensional echocardiography, transesophageal echocardiography, radionuclide ventriculography, and left ventriculography. Left ventricular diastolic function can also be evaluated by ABD, and the results complement those obtained indirectly by pulsed Doppler echocardiographic recordings of the diastolic mitral flow velocity. Recently, ABD has also been used to evaluate left atrial chamber dimensions and atrial function. Thus, real-time ABD is a new echocardiographic method for quantitative assessment of cardiac function that obviates the need for off-line analysis of video images.

Magnetic resonance imaging for quantitation of right ventricular volume in patients with pulmonary hypertension.

Evaluation of right ventricular function in patients with right-sided heart failure is difficult because of the complex anatomy of the right ventricle; the distinct geometry of the dilating, failing right ventricle; its variance from the typical oblate spheroid shape used to model the left ventricle; associated cardiac lesions in patients with right ventricular failure (including tricuspid and pulmonary regurgitation); and the inherent risk of conventional contrast ventriculography. With magnetic resonance techniques, tomographic images of the heart may be obtained at multiple points in the cardiac cycle without the use of intravascular contrast agents. From the end-diastolic and end-systolic images, chamber volume may then be determined directly without any modeling assumptions as to the geometry of the ventricular chamber.

Phase mapping from left ventricular radionuclide ventriculograms: interobserver reliability and accuracy of the programme.

Phase analysis of data from radionuclide ventriculograms is known to provide space-time information on the mechanical emptying of pixels located in the ventricular regions. It could therefore perhaps be useful for detecting abnormal sequences of contraction of the ventricles as well as to localize sites of premature electromechanical action. The phase programme used in this investigation is designed to trace the electromechanical action of the ventricles from colour-coded phase images (first harmonic Fourier transform), not only visually from a cinematic representation, but particularly from a data output of x, y coordinates and phase angles of sites chosen as they empty in the ventricular regions. Six healthy baboons were subjected to conventional radionuclide ventriculography, performed hourly for the duration of 11 h under anaesthesia. The programme was used by two independent observers to map the progression of emptying for each of the thus acquired 66 left ventricular phase images. The interobserver reliability and the accuracy achieved in mapping normal contraction patterns was found to be good. Abnormalities which appeared during the prolonged anaesthesia and which were confirmed with 12 lead electrocardiography were likewise detected consistently.

Microcomputer stereotactic atlas.

A stereotactic atlas to determine thalamic target sites has been incorporated into a microcomputer. Variability studies of the thalamus with mean and standard deviations of nuclear borders are depicted graphically for overlay onto operative images. Internal landmarks traditionally used to reference target points for functional stereotaxis may be determined by conventional ventriculography or derived from magnetic resonance scans. Modeling of polyline vertices established from gray scale contour mapping and atlas reconstructions further enhance the spatial understanding of relationships to midline structures. Computer integration of anatomic reference points, graphically depicted images and stereotactic atlas data into head frame coordinates can be accomplished. This method is consistent with established stereotactic techniques and allows the visual conceptualization of imaged and graphic data for functional stereotaxis.

Feasibility, reliability, and advantage of utilizing low contrast dose digital subtraction ventriculography in a conventional catheterization laboratory

Ventriculography was performed with conventional biplane fluoroscopic equipment; a 1:4 dilution of contrast medium in a standard injectate volume was delivered by a power injector. The biplane images were acquired with two video tape recorders and enhanced by means of a portable digital image processor. By a simple modification and calibration of our standard light pen-computer system, volumes could be calculated and global and segmental wall motion analysis performed. Fifteen patients underwent conventional and low-dose left ventriculography. Good correlation was found in end-diastolic volume (EDV), in end-systolic volume (ESV), and in ejection fraction (EF) ( r = 0.90, r = 0.93, and r = 0.92, respectively). The quality of the images enabled a frame-by-frame analysis of a cardiac cycle to be performed ( r = 0.99 when compared in one patient) and regional wall motion abnormalities identified (21 out of 23 abnormal segments). Although conventional ventriculography caused a rise in left ventricular end-diastolic pressure (17 ± 8 vs 23 ± 11, p < 0.002) and no change in systolic blood pressure (132 ± 23 vs 135 ± 23, p > 0.5), low-dose ventriculography had no effect on left ventricular end-diastolic pressure (18 ± 7 vs 21 ± 10, p > 0.05) and produced a rise in systolic blood pressure (144 ± 20 pressure (18 ± 7 vs 21 ± 10, p > 0.05) and produced a rise in systolic blood pressure (144 ± 20 vs 149 ± 22, p < 0.05). A system of digital enhancement that is capable of producing high-quality ventriculograms with lessened contrast morbidity can be assembled with minimal expense and adapted to any conventional catheterization laboratory.

Methodology and clinical experience with computed tomography and a computer-resident stereotactic atlas.

We have developed a computer-resident stereotactic atlas of the human brain that quantitatively defines subcortical structures within anatomical landmarks detected on obliquely reconstructed computed tomography (CT) slices. Horizontal stereotactic atlas sections can be stretched and contracted by polar transformation and labeled by a computer to fit within these CT scan-defined landmarks. The stereotactic coordinates of any substructure on the atlas-labeled CT slice may then be calculated by the computer and expressed in mechanical adjustments on a stereotactic surgical frame located in the operating room. We demonstrate the use of this method in the stereotactic treatment of movement disorders as an augmentation to conventional ventriculography and microelectrode recording.

Quantitative Assessment of Global and Regional Left Ventricular Function With Low-contrast Dose Digital Subtraction Ventriculography

Few studies have compared the use of low-contrast dose digital subtraction ventriculography with conventional ventriculography for quantitative assessment of both global and regional left ventricular function. Accordingly, 34 patients underwent conventional ventriculography using 36 ml of ionic contrast material and digital ventriculography (mask-mode) using 10 ml of contrast diluted in 10 ml of saline and injected over two seconds. Data from two patients were excluded because of ectopy during cineventriculography and from one because of ectopy during both studies. End-diastolic and end-systolic volumes were calculated from both studies by an area-length method and used to calculate ejection fractions. Regional wall motion was quantitated by the centerline method. Results of linear regression analysis demonstrated high correlations for all parameters (end-diastolic volume, r = 0.85; end-systolic volume, r = 0.93; ejection fraction, r = 0.92; quantitative regional wall motion, r = 0.90). Thus, low-contrast dose digital subtraction ventriculography provides an accurate assessment of both global and regional ventricular function and minimizes the required dose and inherent risks of contrast media.

Digital subtraction angiography in the evaluation of left ventricular function and wall motion in man.

The purpose of this study was to examine the usefulness of digital subtraction angiography in the evaluation of left ventricular function (LVF). LVF was examined in 24 patients by three methods, (a) conventional ventriculography using an intraventricular injection (CLV) of 40 ml of contrast medium, (b) small volume (10-15 ml) left ventriculogram (SVLV) and (c) intravenous injection of 30 ml contrast medium (IVLV). Images were recorded via a conventional image intensifier--TV chain on to video tape and later analysed using a nuclear medicine computer with a digital interface. There was excellent correlation of ejection fraction and wall motion abnormalities between CLV and SVLV methods (r = 0.92 and r = 0.71, respectively) and good correlation between CLV and IVLV methods (r = 0.88 and r = 0.67, respectively). However, only minimal contrast induced premature ventricular contractions were observed in either the SVLV or IVLV methods compared with approximately 60% in the CLV method. Exclusion of studies containing ectopic cardiac cycles considerably improved the correlation between CLV and SVLV (r = 0.97) and between CLV and IVLV methods (r = 0.95). In conclusion, our results indicate that conventional left ventriculography may be replaced by either intravenous or small volume intraventricular methods with little loss of wall motion definition or error in ejection fraction estimation. The less invasive nature of the SVLV and IVLV methods should increase the usefulness of left ventriculography and extend its application to the assessment of left ventricular reserve under stress and during drug intervention.

Computer graphics with computerized tomography for functional neurosurgery.

A computer graphics technique for computer-assisted stereotactic surgery is presented. The program is designed to aid the surgeon by presenting an on-line graphics display of stereotactic probes and electrodes superimposed on cross sections of the human brain stem. This technique simulates an otherwise blind surgical procedure on a graphics screen for use during surgery. An earlier system based around the DEC MINC-11 BA computer system has been used by the authors for the performance of stereotactic surgery with conventional ventriculography. This system has been upgraded and is now configured about an even more compact microprocessor-based hardware system with expanded graphics capabilities, which also allows its use with computerized tomography.

Valve Replacement for Chronic Mitral Insufficiency; Long-term Follow up Using Technetium Pertechnetate Scintigraphy

Technetium Pertechnetate Scintigraphy was performed in 12 patients (9 men and 3 women, average age 48 +/- 13 years) on an average 19.8 +/- 11 months after valve replacement for chronic mitral insufficiency. Preoperative conventional ventriculography had revealed increased enddiastolic and endsystolic volumes (230.9 +/- 66 resp. 73.5 +/- 26 ml). 59.4 +/- 9% of the stroke volume (157.5 +/- 47 ml) regurgitated into the left atrium. Ejection-fraction (67.7 +/- 6%) was normal in all cases. Postoperative first pass technique was employed using a fast multicrystal camera (Baird Atomic, system 77). Volumes were assessed measuring normalized total count rate (count integral of the left ventricle divided by the maximum count density). 19.8 +/- 11 months after valve replacement enddiastolic and endsystolic volumes revealed normal at rest (121.8 +/- 38 resp. 52.8 +/- 35 ml) and after maximum exercise (122.0 +/- 29 resp. 37.6 +/- 22 ml). Ejection fraction responded physiologically to exercise by rising from 57.7 +/- 12 to 69.7 +/- 10%.

Comparison of left ventricular volumes and ejection fraction by digital intravenous ventriculography and conventional intraventricular ventriculography

Comparison of left ventricular volumes and ejection fraction by digital intravenous ventriculography and conventional intraventricular ventriculography

Transventricular absorption and isotope ventriculography.

A simulation of isotope ventriculography with the use of iodinated I 131 serum albumin in a glass ventricular model is used for comparison with conventional air ventriculography. The poor resolution of the rectilinear scanning method does not allow good definition of the true ventricular outline. The geometry of a rectilinear scanning system precludes direct comparisons between scans and air ventriculography. The interpretation of isotope ventriculograms as providing evidence for the transventricular absorption of protein and of cerebrospinal fluid in hydrocephalus is invalid.

Technique and preliminary results of selective catheterization of patients with Blalock-Taussig shunts.

A technique for retrograde catheterization of the pulmonary artery through patent Blalock-Taussig shunts is described. Pulmonary artery pressure and oxygen saturation are determined and pulmonary angiography is performed via this catheter. The angiographic anatomy of the main pulmonary artery and its branches was demonstrated better by this technique than by conventional right ventriculography in 11 patients with severe cyanotic congenital heart disease.