The frequency of asymptomatic urinary system abnormalities in children detected with cineurography imaging during angiocardiography.

IntroductionDiagnostic and interventional catheter angiography of the heart is frequently used in paediatric cardiology. It is also possible to detect urinary system anomalies with cineurography images that may be obtained during angiocardiography. In this study, the aim was to determine the frequency, distribution, and properties of urinary system anomalies accompanying heart diseases, and to find out the effectiveness of cineurographic images in detecting the urinary system anomalies. METHODS: The cineurographic images of 2022 children who had undergone angiocardiography between 1995 and 2015 were retrospectively examined. RESULTS: Urinary system anomalies were detected in 261 of the 2022 cases (12.9%). Of these 261 cases, 148 were males (56.7%), whereas 113 were females (43.3%). Among the heart diseases, the group most accompanied by urinary system anomalies was the non-cyanotic left-to-right shunted heart diseases, which was detected in 120 (39.1%) patients. Pelvicalyceal ectasia was the most common urinary system anomaly encountered and was detected in 89 patients (34.1%). Of the urinary system anomalies cases, 94 detected by cineurography were determined to be clinically severe. When the effectiveness of the cineurography was evaluated using the ultrasonography records of the patients, it was found to have 63.8% accuracy. CONCLUSION: Many of the patients with CHDs concomitantly have urinary system anomalies. It is possible to determine asymptomatic urinary system anomalies using cineurographic imaging during angiocardiography. This may lead to earlier treatments and improved prognosis for the patients, thus making it possible to prevent potential future problems.

Cardiac CT angiography in the emergency department.

OBJECTIVE. Nearly 8 million patients present annually to emergency departments (EDs) in the United States with acute chest pain. Identifying those with a sufficiently low risk of acute coronary syndrome (ACS) remains challenging. Early imaging is important for risk stratification of these individuals. The objective of this article is to discuss the role of cardiac CT angiography (CTA) as a safe, efficient, and cost-effective tool in this setting and review state-of-the-art technology, protocols, advantages, and limitations from the perspective of our institution's 10-year experience. CONCLUSION. Early utilization of cardiac CTA in patients presenting to the ED with chest pain and a low to intermediate risk of ACS quickly identifies a group of particularly low-risk patients (< 1% risk of adverse events within 30 days) and allows safe and expedited discharge. By preventing unnecessary admissions and prolonged lengths of stay, a strategy based on early cardiac CTA has been shown to be efficient, although potential overutilization and other issues require long-term study.

[Application of computational fluid dynamics in hemodynamic research of aortic arch].

OBJECTIVE: To evaluate the application of computational fluid dynamics (CFD) on a patient-specific hemodynamic model of aortic arch. METHODS: The original Dicom format image data of a patient were acquired by computed tomographic angiography (CTA). A 3-dimensional (3D) model based on CFD was constructed through the right amount of boundary conditions and hemodynamic parameters related with flow velocity, shear force and wall stress on lumen were analyzed accordingly. RESULTS: The 3D model based on CFD could reflect the characteristic of flow velocity, shear force and wall stress on lumen in vitro. (1) The distributions of hemodynamic variables during cardiac cycle were spatiotemporally different. The unidirectional high-speed systolic current was replaced by diastolic eddy current and reversed flow. The distribution of flow velocity and shear stress gradually increased from outer wall of aortic artery to inner wall under the influences of such anatomical factors as vascular branching and distortions of descending aorta; (2) the magnitude and volatility of wall stress in ascending aorta were greater than those of aortic arch and descending aorta, but the least results were at the lateral wall of descending aorta area. In addition, the wall stress of external wall was higher than the lateral wall in the same section. CONCLUSION: The hemodynamic research of aortic arch based on CFD may actually simulate the characteristics of blood flow and wall stress so as to become a new reliable and convenient application tool in etiological diagnosis and surgical planning.

[Cryoballoon ablation for pulmonary vein isolation to treat atrial fibrillation: first experience in Russian Federation].

Cryoballon ablation (CBA) for pulmonary vein (PV) isolation is a new method for catheter-based treatment of patients with atrial fibrillation (AF). The purpose of our work is to describe the CBA technique and to report its short-term results. Methods. CBA was performed in 12 patients (8 men; age 53.1+/-5.7 years) with highly symptomatic drug-refractory AF. Paroxysmal AF was present in 11 and persistent AF - in 1 patient. CBA procedure was carried out under general anesthesia with intubation in 6 and under light sedation in 6 patients. After transseptal access and direct PV angiography, 28 mm-cryoballoon was introduced into the left atrium, and more or equal 2 cryoapplications were delivered to each PV, once good PV occlusion was obtained. PV isolation was verified utilizing a circular mapping catheter. Arrhythmia recurrences were monitored every 3 months after ablation using 24-hour Holter, and additional ECG registrations. Holter monitoring was also performed in a case of symptoms. Results. Complete electrical PV isolation was achieved by only cryoballoon ablation in 11 patients, and additional cryocatheter touch-up ablation was required in left PVs in 1 patient. Total procedure time was 203.1+/-34.2 min, fluoroscopy time - 50.5+/-14.0 min. There were no complications. During a mean follow-up period of 136.8+/-59.8 days 9 (75%) patients were free from arrhythmia recurrence after a single procedure. Redo ablation was required in 1 patient, in whom electrical reconnection to all PVs was documented. Conclusion. CBA is a novel promising technique for treatment of patients with AF, and now is available in Russian Federation. The method standardizes and facilitates interventional AF treatment with acute isolation of 96% PVs. The short-term follow-up shows freedom from atrial tachyarrhythmias in 75% of patients.

Use of 64 slice CT in scimitar syndrome.

INTRODUCTION: Scimitar Syndrome is a relatively rare variety of partial anomalous pulmonary venous connection in which the right pulmonary veins form an anomalous confluence which drains into the infra-diaphragmatic inferior vena cava. The X-ray chest in these patients shows the typical Scimitar Sign. CASE REPORT: We are presenting a patient who was diagnosed to have Scimitar Syndrome on the basis of X-ray chest and echocardiography. Confirmation of diagnosis and precise anatomical characterization was achieved by 64 slice CT angiocardiography. The patient underwent successful surgical correction. Adequacy of procedure was demonstrated by the same procedure. DISCUSSION: scimitar syndrome is a type of partial anomalous venous connection. It consists of sinus venosus type of atrial septal defect, anomalous confluence of right upper and lower pulmonary veins draining into the infra-diaphragmatic inferior vena cava and right lung lower lobe hypoplasia. The X-ray chest shows the characteristic Scimitar Sign. Precise anatomical characterization in required for operative correction and cannot usually be achieved by echocardiography and requires invasive angiocardiography, multi-detector CT angiocardiography or cardiac MRI. We used CT angiocardiography for diagnosis and post-operative confirmation of adequacy of correction.

Comparison of measures of left ventricular function from electrocardiographically gated 82Rb PET with contrast-enhanced CT ventriculography: a hybrid PET/CT analysis.

UNLABELLED: Because of the ultrashort tracer half-life and high positron energy of (82)Rb, PET images acquired with this tracer are noisier and of lower resolution than those obtained with other PET tracers. The validity of electrocardiographic gating using (82)Rb for assessment of left ventricular (LV) function is not well established. To support feasibility, we compared functional parameters from gated (82)Rb PET with simultaneous high-resolution contrast-enhanced CT ventriculography, obtained as a byproduct a CT coronary angiography during hybrid cardiac PET/CT. METHODS: A total of 24 patients underwent PET/CT, consisting of rest and dipyridamole (82)Rb perfusion studies and contrast-enhanced CT angiography, using a 64-slice scanner, for the workup of coronary artery disease. From gated PET images, LV ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) were calculated using 2 commercial products. For functional CT analysis, commercial software using endocardial contour detection was applied. RESULTS: Inter- and intraobserver agreement was good for all methods. On CT, EF was 66% +/- 13%, ESV was 41 +/- 29 mL, and EDV was 115 +/- 36 mL. On PET, EF during dipyridamole was 56% +/- 15% and 52% +/- 15% using the 2 commercial products (P < 0.05 vs. CT), ESV was 36 +/- 28 and 47 +/- 35 mL (P = not significant vs. CT), and EDV was 75 +/- 30 and 91 +/- 33 mL (P < 0.05 vs. CT). Correlations with CT were 0.85 and 0.87 for EF using commercial software, 0.76 and 0.88 for ESV, and 0.60 and 0.68 for EDV (P < 0.01 for all). Bland-Altman analysis confirmed systematic underestimation of EF and EDV by PET versus CT but did not show a significant deviation from linearity. CONCLUSION: Global LV function can be measured reproducibly from gated (82)Rb PET, using different available software products. However, underestimation of EF by (82)Rb PET, compared with CT ventriculography, is present, which is a result of underestimation of EDV from count-poor ED frames. This underestimation needs to be considered for clinical interpretation of (82)Rb PET.

Measurement of left ventricular mass by contrast ventriculography.

BACKGROUND: Elevated left ventricular mass (LVM) has been shown to be an important predictor of adverse cardiac events. Calculation of LVM using contrast ventriculography, as described by Rackley, involves measuring left ventricular wall thickness in a single plane, with assumptions made about ventricular geometry. HYPOTHESIS: We hypothesized that a modification of the Rackley method, involving multiple measurements of left ventricular (LV) wall thickness in 2 orthogonal planes, may add value in the determination of LVM in patients with LV remodeling and dysfunction. METHODS: The LVM was determined in 24 patients with LV dysfunction who had undergone both cardiac magnetic resonance imaging (CMRI) and contrast left ventriculography. Right anterior oblique (RAO) and left anterior oblique (LAO) still frames in diastole were used to measure LV length, chamber area, and wall thickness. From these variables, LV volume, myocardial volume, and LVM were calculated. The LVM calculations using an average wall thickness from the LAO and RAO projections were compared with LVM measured by CMRI. RESULTS: Eighty eight percent of patients had hypertension, 100% had coronary artery disease, and mean left ventricular ejection fraction by contrast left ventriculography was 41 +/- 14%. Averaging left ventricular wall thickness from RAO and LAO projections using biplane ventriculography for LVM calculation yielded a strong correlation (r = 0.77, p < 0.01) with LVM calculated from CMR. CONCLUSIONS: In patients with left ventricular dysfunction, biplane left ventricular wall thickness measurements for contrast ventriculography LVM calculations render a strong correlation with LVM calculated by CMRI.

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.

Echocardiographic and angiographic comparison of ductal dimensions in dogs with patent ductus arteriosus.

BACKGROUND: Transcatheter occlusion of patent ductus arteriosus (PDA) is a minimally invasive treatment option in dogs. Device selection based on appropriately acquired PDA dimensions and morphology can minimize procedural complications, including minimizing residual ductal flow and inappropriate embolization. HYPOTHESIS: Transesophageal echocardiographic (TEE) derived minimum ductal diameter measurements would most accurately reflect angiographic measurements. Color Doppler (CD) TEE and transthoracic echocardiographic (TTE) ductal measurements would overestimate two-dimensional (2D) measurements. ANIMALS: Fifteen client-owned dogs with PDA. METHODS: PDA dimensions obtained with angiography, 2D and CD TTE, 2D and CD TEE from the right and left views were prospectively evaluated. RESULTS: PDA dimensions were measured by using TEE most closely approximated angiographic measures. CD TTE and TEE frequently overestimated angiographic measures of minimum ductal diameter. TEE accurately identified a type III (tubular) PDA morphology in 1 dog. Fourteen of 15 dogs were determined to have hemodynamically significant reductions in left to right shunting documented by a first-pass nuclear angiocardiographic ratio of pulmonary to systemic blood flow < or = 1.2 and trivial (n = 3) to no (n = 11) CD TTE flow at approximately 1 month after PDA occlusion. CONCLUSIONS: TEE provided accurate anatomic information regarding PDA morphology and closely approximated angiographic ductal dimensions while aiding in both coil deployment and confirmation of intra-operative ductal closure.

Assessment of cardiovascular function by digital angiocardiography.

A methodology for computerized digital videoangiocardiography is briefly described. Single or biplane projection image series from the cardiovascular system are combined with the corresponding physiologic (electrocardiogram, blood pressure, etc.) reference data, digitized and stored as a block of simultaneously available information representing anatomic and functional aspects of the cardiovascular system. Simple mask mode and more complex modes of digital subtraction, image combination and manipulation techniques, as developed during the last decade, are mentioned. These techniques are primarily useful to separate the contrast bolus from the background, thereby allowing contrast enhancement with less contrast medium injected selectively, or so-called noninvasive intravenous angiocardiography. Ventricular function can be assessed by these simple digital image processing techniques. This has been proved for determining right ventricular volumes and ejection fraction with respect to reproducibility and accuracy using conventional biplane angiocardiography as reference. More complex techniques for the assessment of function, in particular blood flow distributions in the systemic circulation, are described using information from the whole digitized angiocardiographic image series by extracting time and volume parameters from the complete matrix of pixel densograms. Various modes of extraction and display of time parameters allow a generation of parametric images that display heretofore unavailable flow patterns reflecting the progress of the contrast bolus within the arterial tree. Based on an adequate temporal segmentation (for example, time segments of one cardiac cycle) and simultaneous volume determination of the circulatory structure from the area of the densogram, relative and absolute flow as well as regional flow distribution in a branching arterial system can be determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Radionuclide angiocardiography in children.

Clinical use of radiotracer techniques in pediatric cardiology is increasing. Three basic methods being employed are first pass radionuclide angiocardiography, gated blood pool scanning and myocardial perfusion scintigraphy. These methods are rapid, safe and accurate. They are minimally invasive and result in a low radiation dose to the patient. The development of ultrashort-lived radionuclides (such as iridium-191m with a half-life of only 5 seconds), improvements in nuclear imaging instrumentation and numerical analysis should contribute to a further utilization of these methods.

Exercise left ventriculography utilizing intravenous digital angiography.

Exercise left ventriculography has been shown to be a sensitive and specific tool for the detection of coronary artery disease. At the present time, such studies require radionuclide-base methods. Computer-based techniques recently have been shown to provide high resolution images of the left ventricle when the levophase of an intravenous injection of radiopaque contrast medium is imaged with fluoroscopy. To evaluate the possible efficacy of using "intravenous digital subtraction left ventriculograms" in exercise ventriculography, such ventriculograms were performed at rest and during maximal supine bicycle exercise in 31 patients. Studies that could be analyzed were obtained in 29 patients. In 21 patients with coronary artery disease, ejection fraction was 58% at rest and 45% with exercise (p less than 0.001 vs. rest). In contrast, in seven patients with no coronary artery disease, ejection fraction was 65% at rest and 69% with exercise (difference not significant). In a subgroup of 8 patients with "severe" coronary obstruction, the change in ejection fraction from rest to exercise was -18%, while in the remaining 13 patients with less severe disease, it was -9% (p less than 0.001). All patients with coronary artery disease manifested new or worsening segmental wall abnormality with exercise, compared with two of seven patients without coronary disease (p less than 0.01). Sixteen patients underwent rest and exercise radionuclide cineangiography in addition to digital subtraction angiography. There was a strong correlation between the two techniques for ejection fraction at rest (r = 0.78, p less than 0.001), ejection fraction and with exercise (r = 0.83, p less than 0.001) and change in ejection fraction from rest to exercise (r = 0.88, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Pitfalls in diagnosis and clinical, echocardiographic, and hemodynamic findings in endomyocardial fibrosis: a 25-year experience.

Endomyocardial fibrosis (EMF) is a fascinating disease entity of unknown etiology. It is prevalent in the tropical zone. Its essential features are the formation of fibrous tissue on the endocardium and to a lesser extent in the myocardium of the inflow tract and apex of one or both ventricles. It results in endocardial rigidity, atrioventricular valve incompetence secondary to papillary muscle involvement, and progressive reduction of the cavity of the involved ventricle leading to restriction in filling and atrial enlargement. This article will present 21 patients with EMF who were initially referred to our hospital from 1979 to 2004 with different diagnoses: rheumatic heart disease with mitral and or tricuspid regurgitation (n = 9), constrictive pericarditis (n = 6), restrictive cardiomyopathy (n = 1), hypertrophic cardiomyopathy apical type (n = 2), dilated cardiomyopathy (n = 2), and Ebstein malfunction of the tricuspid valve (n = 1). The clinical, echocardiographic, hemodynamic, and angiographic findings in these 21 patients are presented; echocardiographic findings lead to the right diagnosis. The presence of a small ventricle with obliteration of the apex and large atrium shown on two-dimensional echocardiography is highly suggestive of EMF.

[Single plane Simpson's method for measurement of right ventricular volume by X-ray ventriculography].

OBJECTIVE: To study the validity of single plane Simpson's method with conventional X-ray ventriculography for estimation of right ventricular (RV) volume. METHODS: Fifteen human RV casts were obtained from 15 subjects who died from non-cardiac causes within 24 hours after death. These casts were photographed respectively and their volumes were calculated by using the single plane Simpson's method based on a new half-circle model. The actual RV cast volumes were determined by water displacement method. RESULTS: The actual RV volume was (64.23 +/- 24.51) ml and the calculated volume was (58.04 +/- 24.45) ml. The calculated RV volume underestimated the actual volume by (6.19 +/- 12.38) ml, but there was no significant difference between the actual and the calculated RV volume (P > 0.05). There was a significant correlation between the actual cast volume and the calculated volume (r = 0.983, P < 0.01). The regression equation was: RV actual volume = 1.074 x (RV calculated volume). CONCLUSION: RV volume calculated by single plane Simpson's method with conventional X-ray ventriculography is accurate and deserves further study.

Quantitative evaluation of the regional left ventricular function in normal subjects by means of cineangiocardiography.

A method for analysing left ventricular cineangiograms is described, which not only provides information on the overall ventricular performance, but also evaluates the regional contraction of the left ventricle and the related haemodynamic patterns. This simplified Chapman's method (slice method) makes it possible to calculate the end-diastolic, end-systolic volumes, the stroke volume and the ejection fraction of the zones into which the left ventricle is divided by a longitudinal and by three transverse axes, according to Herman's technique. The hemiventriculograms of 21 normal subjects in the AP projection were evaluated using this method and a 10 of them were also studied in RAO projection. A uniform left ventricular contraction pattern was found for three hemiventricles outlined by the anterolateral, lateral, and postero-medial walls (ejection fraction 71.7 +/- 5.1%, 71.6 +/- 5.9%, 70.4 +/- 5.1%, respectively), the regional and zonal ejection fraction (EFR, EFZ) being similar in both projections. The ejection fraction of the hemiventricle outlined by the septal wall was, however, lower (65.6 +/- 6.0%). The standard zonal function curves of the left ventricle in normal subjects was then calculated on the basis of the results obtained, in order to assess, by comparison, zonal function abnormalities in cardiac patients.

Evaluation of single plane angiography for left ventricular volume in the intact dog.

Technique and errors of quantitative single plane ventriculography (SPV), and the methods of Dodge and Sandler (Dodge et al, 1962; Sandler and Dodge, 1968) and Greene et al (1967) for determining left ventricular (LV) volume by SPV were evaluated in the intact dog. Stroke volume (SV) and cardiac output (Q) by ventriculography were compared with those obtained by the Fick and dye dilution methods, and their combination. The end-diastolic (EDV) and end-systolic volume (ESV) corrected by appropriate regression equations, the SV (SV=EDV - ESV), and the ejection fraction (EF) were: Dodge and Sandler, 2.26 1.35, 0.91 ml/kg, and 0.42; Greene et al, 2.41, 1.50, 0.91 ml/kg, and 0.39. Using adequate methods, accurate correction for x-ray image magnification, and the appropriate regression equations the standard error of LV volume calculation by single plane radiography, due to unavoidable technical inaccuracies, should not exceed 10% for a single measurement and 5% for the average of two or more successive cardiac cycles. The systematic overestimation of LV volume inherent in ventriculography, and caused by the addition of contrast medium, should not exceed 5% of the true value.

The Left Main Bifurcation Angle and Changes Throughout the Cardiac Cycle: Quantitative Implications for Left Main Bifurcation Stenting and Stents.

OBJECTIVE: The objective of this study was to quantify the left main (LM) bifurcation angles and their changes throughout the cardiac cycle. BACKGROUND: LM stenting is an accepted alternative to coronary artery bypass grafting. However, the LM bifurcation has great anatomic variability. Three-dimensional angles and their cyclic changes are important for coronary stenting. METHODS: Patients undergoing coronary computed tomography angiography (CCTA) for chest pain were scanned and analyzed in three-dimensional views for left main-left anterior descending (LM-LAD), left main-left circumflex (LM-LCX), and left anterior descending-left circumflex (LAD-LCX) angles and their cyclic changes. Calculations and assessment of angles, angular variability, and how these angles change throughout the cardiac cycle were analyzed. RESULTS: Forty-four patient scans were analyzed. The median end-diastolic LM-LCX angle was 130° and the LAD-LCX was 74°. Median end-systolic angle for the LM-LCX was 133°, and LAD-LCX was 69°. Large differences were found across all three absolute angles (LM-LCX, LAD-LCX, LM-LAD). Marked variability also occurred in how these angles changed throughout the cardiac cycle. CONCLUSIONS: LM bifurcation geometry in patients shows marked absolute angle variability, as does diastolic-systolic angle movement. LM bifurcation stents should accommodate wide interpatient bifurcation angles at rest for both the LM-LAD and LM-LCX angles.

Cardiac involvement in myotonic muscular dystrophy.

Cardiac illness in myotonic muscular dystrophy (MyD) is infrequent, but subclinical cardiac involvement in MyD is very common (found in 42 of 46 subjects) and may be responsible for sudden death. In this series, we found ECG abnormalities in 72%, left ventricular dysfunction in 70%, mitral valve prolapse in 37%, and sudden death in 4%. Four deaths during the study period were due to acute left ventricular failure, one to sepsis and respiratory insufficiency, and one was unexplained. We did not find ominous bradyarrhythmias or atrioventricular block, evidence of congestive heart failure, noninvasive evidence of coronary artery disease, or any correlation of type or amount of cardiac involvement with any clinical parameter such as age, sex, or severity of systemic dystrophy. We feel tachyarrhythmias may play as important a role in sudden death of myotonic muscular dystrophy subjects as bradyarrhythmias, and coronary artery disease in addition to cardiac dystrophy may produce arrhythmias and myocardial dysfunction in myotonic muscular dystrophy. In addition, some subjects have an unusual form of resting left ventricular dysfunction which improves with exercise. The most important problem in the clinical management of myotonic muscular dystrophy subjects is sudden death, and the solution does not appear to be empiric ventricular pacing. Our recommendations for prophylaxis of sudden death in myotonic muscular dystrophy are noninvasive investigation of coronary artery disease in subjects with significant risk factors, with angiography and surgery if indicated: detailed evaluation of syncopal and presyncopal events, including electrophysiologic testing, with pacemaker or antiarrhythmic drug therapy if indicated; and consideration of ventricular pacing of asymptomatic subjects if severe bradycardia or marked intraventricular conduction delay develops during follow-up, serial 12-lead ECGs. The documentation of tachyarrhythmias during sudden death and syncopal episodes in myotonic muscular dystrophy subjects makes ventricular pacing alone an uncertain modality for prevention of sudden death in subjects with only mildly lengthened PR or QRS intervals, and suggests a combination of pacemaker and antiarrhythmic drug therapy for the myotonic muscular dystrophy subject with syncope of no apparent cause.

Deconvolution analysis in radionuclide quantitation of left-to-right cardiac shunts.

A poor bolus injection results in an unsatisfactory quantitative radionuclide angiocardiogram in as many as 20% of children with possible, left-to-right (L-R) cardiac shunts. Deconvolution analysis was applied to similar studies in experimental animals to determine whether dependence on the input bolus could be minimized. Repeated good-bolus, prolonged (greater than 2.5 sec), or multiple-peak injections were made in four normal dogs and seven dogs with surgically created atrial septal defects (ASD). QP/QS was determined using the gamma function. The mean QP/QS from ten good-bolus studies in each animal was used as the standard for comparison. In five trials in normal animals, where a prolonged or double-peak bolus led to a shunt calculation (QP/QS greater than 1.2 : 1), deconvolution resulted in QP/QS = 1.0. Deconvolution improved shunt quantitation in eight of ten trials in animals that received a prolonged bolus. The correlation between the reference QP/QS and the QP/QS calculated from uncorrected bad bolus studies was only 0.39 (p greater than 0.20). After deconvolution using a low pass filter, the correlation improved significantly (r = 0.77, p less than 0.01). The technique gave inconsistent results with multiple-peak bolus injections. Deconvolution analysis in these studies is useful in preventing normals from being classified as shunts, and in improving shunt quantitation after a prolonged bolus. Clinical testing of this technique in children with suspected L-R shunts seems warranted.