Biomedical subjects
Publications and source records attributed to J J Wheller.
Intrapericardial teratomas are rare primary cardiac tumors of infancy and childhood. We describe three neonates with intrapericardial teratomas diagnosed during fetal life and treated after birth. Clinical and anatomic considerations suggest that cardiopulmonary bypass provides for safe tumor dissection and complete excision of the tumor, thereby decreasing the risk of recurrence.
This paper examines the use of the algebraic reconstruction technique (ART) and related techniques to reconstruct 3-D objects from a relatively sparse set of cone-beam projections. Although ART has been widely used for cone-beam reconstruction of high-contrast objects, e.g., in computed angiography, the work presented here explores the more challenging low-contrast case which represents a little-investigated scenario for ART. Preliminary experiments indicate that for cone angles greater than 20 degrees, traditional ART produces reconstructions with strong aliasing artifacts. These artifacts are in addition to the usual off-midplane inaccuracies of cone-beam tomography with planar orbits. We find that the source of these artifacts is the nonuniform reconstruction grid sampling and correction by the cone-beam rays during the ART projection-backprojection procedure. A new method to compute the weights of the reconstruction matrix is devised, which replaces the usual constant-size interpolation filter by one whose size and amplitude is dependent on the source-voxel distance. This enables the generation of reconstructions free of cone-beam aliasing artifacts, at only little extra cost. An alternative analysis reveals that simultaneous ART (SART) also produces reconstructions without aliasing artifacts, however, at greater computational cost. Finally, we thoroughly investigate the influence of various ART parameters, such as volume initialization, relaxation coefficient lambda, correction scheme, number of iterations, and noise in the projection data on reconstruction quality. We find that ART typically requires only three iterations to render satisfactory reconstruction results.
The prime motivation of this work is to devise techniques that make the algebraic reconstruction technique (ART) and related methods more efficient for routine clinical use, while not compromising their accuracy. Since most of the computational effort of ART is spent for projection/backprojection operations, we first seek to optimize the projection algorithm. Existing projection algorithms are surveyed and it is found that these algorithms either lack accuracy or speed, or are not suitable for cone-beam reconstruction. We hence devise a new and more accurate extension to the splatting algorithm, a well-known voxel-driven projection method. We also describe a new three-dimensional (3-D) ray-driven projector that is considerably faster than the voxel-driven projector and, at the same time, more accurate and perfectly suited for the demands of cone beam. We then devise caching schemes for both ART and simultaneous ART (SART), which minimize the number of redundant computations for projection and backprojection and, at the same time, are very memory conscious. We find that with caching, the cost for an ART projection/backprojection operation can be reduced to the equivalent cost of 1.12 projections. We also find that SART, due to its image-based volume correction scheme, is considerably harder to accelerate with caching. Implementations of the algorithms yield run-time ratios TSART/TART between 1.5 and 1.15, depending on the amount of caching used.
OBJECTIVES: This study was performed to determine the frequency of patent ductus arteriosus (PDA) reopening and the factors that may predict reopening after successful coil occlusion. BACKGROUND: Transcatheter coil occlusion is a widely used and accepted method to close a PDA. After documented successful coil occlusion, we found PDAs that reopened. We hypothesized that specific factors are involved in those that reopened. METHODS: All patients who underwent percutaneous transarterial PDA coil occlusion were studied. Successful coil occlusion was documented. PDA reopening was determined when Doppler-echocardiography (DE) performed after the procedure was negative for PDA flow but at follow-up demonstrated PDA shunting. Patients with a reopened PDA were compared with all other patients in evaluating independent variables. RESULTS: Coil occlusion for PDA was attempted in 22 patients. Clinical success was achieved in 20 patients (91%), and DE was negative for PDA shunting in 19 patients (90%). At follow-up, five patients demonstrated reopening. The PDA minimal diameter was 1.4 +/- 0.5 mm (mean +/- SD) for the reopened group and 1.2 +/- 0.7 mm for the other patients. The PDA length was 2.9 +/- 1.9 mm for the reopened group and 7.1 +/- 3.2 mm for all other patients. All those with type B PDA were in the reopened group. When independent variables were compared between groups, only PDA length and type B PDA predicted reopening (p < 0.05). CONCLUSIONS: PDA reopening may occur after successful coil occlusion. Short PDA length and type B PDA are associated with reopening. The data suggest that in such anatomy, alternative strategies to the current coil occlusion technique should be considered.
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OBJECTIVES: We evaluated the clinical utility of a comprehensive program of prenatal diagnostic testing for congenital anomalies in pregnancies complicated by insulin-dependent diabetes mellitus. STUDY DESIGN: Data were retrospectively analyzed from 289 diabetic women and their newborns from August 1987 to July 1993. Our protocol included initial hemoglobin A1 and maternal serum alpha-fetoprotein determinations and comprehensive fetal ultrasonography inclusive of a standard four-chamber view of the heart and detailed multiimage fetal echocardiography. RESULTS: Anomalies were identified in 29 of 289 (10%) fetuses and neonates: 12 cardiac only, 14 noncardiac, and 3 combined. In 21 of the 29 (72%) neonates the anomalies were detected prenatally. Twelve of 15 (80%) cardiac and 10 of 17 (59%) noncardiac lesions were identified prenatally. Cardiac lesions, especially of the cardiac septum and great vessels, accounted for 50% of all fetal defects. Malformations of the neuroaxis, skeleton, and genitourinary system were also detected. There were six neonatal deaths and four therapeutic pregnancy terminations associated with congenital anomalies. Although the hemoglobin A1 level was statistically significantly increased in 22 mothers of anomalous fetuses (p = 0.017), the actual difference between affected and nonaffected pregnancies was not clinically meaningful and much overlap occurred. Although 96% of women with a normal hemoglobin A1 level were delivered of normal infants, only 14% of those with an elevated value had a malformed fetus. Similarly, although 89% of gravid women with a normal maternal serum alpha-fetoprotein level were delivered of nonaffected fetuses, only 7.3% of patients with an elevated value had a malformed fetus. For the detection of cardiac defects, the sensitivity of the four-chamber view compared with detailed multiimage fetal echocardiography was 33% and 92%, respectively. CONCLUSIONS: This study demonstrates the utility of a comprehensive program to detect fetal anomalies in pregnancies complicated by diabetes mellitus.
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Ten patients with coronary artery fistulae were identified from records at Columbus Children's Hospital between 1974 and 1993. Clinical presentations of patients were quite variable, from 1 day to 20 years of age. Symptoms ranged from none to severe cardiorespiratory failure requiring extracorporeal membrane oxygenation. Long term follow-up revealed one sudden death and one spontaneous closure of the fistula. This lesion should be ruled out in patients who present as extracorporeal membrane oxygenation candidates. Patients with mild forms of this lesion may be followed up medically if the left to right shunt is inconsequential, because spontaneous closure is a possibility. Because of the risk of sudden death, close long-term follow-up is mandatory even for operated patients, and antiplatelet therapy should be considered for these patients.
Current practice patterns relating to pediatric cardiac catheterization (Cath) have considerable economic implications. The decreased cost and risk of noninvasive methods such as echocardiography (ECHO) and magnetic resonance imaging (MRI) make them attractive alternative diagnostic methods if they can sufficiently define cardiac anatomy and the need for surgical intervention. We reviewed a recent cardiac surgical series of 465 cases in 1.5 years to determine how often a Cath was performed prior to surgery. Overall, 59.4% of the procedures were preceded by a Cath (76% of open heart operations, and 26.7% of closed heart operations). We specify the situations where we feel enough information is available for preoperative decision making from non-invasive testing, and we present some diagnostic pitfalls that have been encountered.
Current ultrasound technology allows for accurate evaluation of the fetal heart. To evaluate the importance and accuracy of the routine clinical use of fetal echocardiography at our center, a consecutive series of 338 fetal cardiac studies of 323 patients was reviewed. Average gestational age was 24 weeks (range, 17 to 39 weeks). Forty-seven (15%) patients with abnormal conditions were detected. The most common indication for fetal cardiac scan was a family history of congenital heart disease (28%). Other indications were maternal diabetes mellitus (25%), fetal dysrhythmia (14%), other major defect (10%), drug exposure (10%), and obstetrician suspicion of fetal congenital heart disease on routine scan (10%). The highest yield of significant abnormal findings was among those referred for dysrhythmia (31%) and obstetrician suspicion of congenital heart disease (29%). Five fetuses with sustained supraventricular tachycardia and hydrops were successfully treated. The combination of fetal bradycardia and structural heart disease was the most ominous finding. Fifteen (4.6%) patients had clear changes in management based on the fetal echocardiogram. Our experience suggests that the routine use of fetal echocardiography is accurate and an important part of the overall management of the pregnancy considered at risk for producing an infant with congenital heart disease.
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Surgical procedures for aortic valve stenosis may be considered either corrective or palliative. During a 22-year period from 1962 to 1984, 120 patients required operation for aortic valve stenosis. The operations done included 117 valvotomies and three initial valve replacements. Six patients, five infants and a 7-year-old girl, died at operation. The remaining 114 patients were followed up for 1 to 23 years (mean 8.7 years). Twenty-six patients (23%) required a second operation 1 to 15 years (mean 6.8 years) after initial valvotomy. Six patients (5%) required a third operation 3 months to 8 years (mean 4.4 years) after the second operation. Eighteen of the 26 patients (69%) having second operations required valve replacement. All third operations were valve replacements. No perioperative deaths occurred at the second and third operations. There were four sudden late deaths (3.5%). Eighty-four of the 114 patients (74%) followed up for 1 to 23 years (mean 7.7 years) have had a satisfactory result from initial valvotomy, being free of symptoms and major events (stroke, endocarditis, sudden death), and have not required reoperation. Fifty-nine percent of a subgroup of 22 patients followed up for a mean of 17.7 years have had a satisfactory result from initial valvotomy.
Rheumatic fever has been disappearing in the United States, especially during the past two decades. In the past two years, however, there have been 40 patients seen at the Columbus (Ohio) Children's Hospital diagnosed as having acute rheumatic fever. In marked contrast to the infrequency during the preceding ten years. Twenty of the 40 patients had carditis. Five of these patients were suffering from heart failure, and there was one death. The cause for this outbreak has not yet been found, but some possible causes are discussed. A possible nationwide resurgence of this disease may be heralded by our experience and that of others.
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Congenital contractural arachnodactyly (CCA) is a connective tissue disorder sharing many of the clinical manifestations of Marfan's syndrome. The case presented emphasizes that severe cardiac involvement may be manifested in the neonate with CCA, thus altering the more characteristic benign prognosis of CCA.
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A premature infant who developed Budd-Chiari syndrome as a complication of total parenteral nutrition through an inferior vena cava catheter is presented. A novel approach to the treatment of this otherwise lethal condition is described. This very unusual complication in pediatric patients may be seen with increased frequency as more premature infants are treated with central vein total parenteral nutrition.