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T W Ovitt

Publications and source records attributed to T W Ovitt.

At least 37 records · Page 2Linked to original sources
PubMed1982

Two dimensional echocardiography and intravenous digital video subtraction angiography for diagnosis and evaluation of double aortic arch.

Two infants and one 7 year old child with double aortic arch are described in whom subcostal two dimensional echocardiography identified the bifurcation of the aorta high within the thorax and imaged the proximal portions of the right and left aortic arches. In one of the infants and in the 7 year old child, the diagnosis was confirmed using intravenous digital video subtraction angiography, thus avoiding aortography and permitting accurate evaluation of the anatomic features. All cases were confirmed surgically. If X-ray examination after barium swallow and clinical history are suggestive of double aortic arch, two dimensional echocardiography is useful in verifying this possibility. Intravenous digital video subtraction angiography provides the capability for precise documentation of the anatomic features.

Angiography↗
PubMed1982

The potential impact of digital video subtraction angiography on screening for renovascular hypertension.

The success of digital video subtraction angiography (DVSA) in screening hypertensive patients for renal artery stenosis and the apparent value of percutaneous transluminal angioplasty (PTA) prompted re-evaluation of the philosophy of indiscriminate medical therapy for newly discovered cases of hypertension. DVSA was diagnostic in 87% of cases. The cost of screening for renovascular hypertension by DVSA and treatment by PTA when feasible is about the same as that of medical therapy. Considering the problems of noncompliance and drug side effects associated with medical antihypertensive therapy, DVSA screening for renovascular hypertension in a broader population seems both medically and economically sound.

Angiography↗
PubMed1982

Intracranial applications of digital intravenous subtraction angiography.

The intracranial vessels of 175 patients were examined with digital intravenous subtraction angiography. The equipment and the technique of the examination are briefly described. Of these patients, 129 underwent intravenous cerebral angiography in conjunction with examination of the extracranial carotid arteries for suspected arteriosclerotic disease. Postoperative and occasionally preoperative studies of intracranial aneurysms and arteriovenous malformations were performed in 16 patients, patency and flow patterns of extracranial-to-intracranial bypass grafts were evaluated in 11 instances, and selected vascular cranial and intracranial neoplasms were studied in 16 cases. Venous sinus occlusion has also been diagnosed by this technique. In many instances, digital intravenous subtraction angiography can replace conventional cerebral angiography.

Adult↗
PubMed1982

Digital subtraction angiography of peripheral vascular bypass procedures.

Without premedication or special preparation, digital video subtraction angiography, also known as photoelectronic intravenous angiography, was effectively used for evaluating patients who had undergone peripheral vascular reconstructive procedures. Thirty-eight studies in 20 patients were performed using computer contrast enhancement after an intravenous injection. Patency of arterial grafts was thereby evaluated, thus obviating further routine angiography. Graft patency, even of small complex graft sites, was easily recognized. Occlusions were also readily identified. Patient acceptance was excellent since the procedure is almost painless and can be done on an outpatient basis. The technique is fast, safe, and less expensive than routine angiography.

Angiography↗
PubMed1982

Evaluation of potential renal donors and renal allograft recipients: digital video subtraction angiography.

Digital video subtraction angiography is a safe, easily performed, outpatient procedure that was applied to evaluating the arterial anatomy of 11 potential renal donors and 22 examinations of 19 renal allograft recipients. Digital intravenous angiography depicted the number and position of renal arteries preoperatively in renal donors and excluded renal arterial or parenchymal disease. It accurately defined transplant arterial stenoses and demonstrated the status of the intrarenal circulation. No morbidity nor decreased renal function resulted. Digital video subtraction angiography has become the procedure of choice for these referrals at this institution.

Adult↗
PubMed1982

Digital video subtraction angiography of the cervical and cerebral vasculature.

A digital video subtraction angiography unit developed at the University of Arizona is described. The system allows the angiographic evaluation of the cervical and cerebral vasculature by means of intravenous injection of contrast material. The procedure is performed on outpatients and is reliable, safe, and economical. The authors have evaluated suspected arterial and venous occlusive disease, certain aneurysms and tumors, and postoperative results of vascular bypass procedures and aneurysm clipping. The clinical application of the technique is shown with appropriate case presentations.

Aged↗
PubMed1981

Accuracy of two-dimensional echocardiography in the detection of aneurysms of the ventricular septum.

Eight children with angiographically proven aneurysm of the membranous ventricular septum (AVS) associated with ventricular septal defect were studied by real-time cross-sectional echocardiography. A curvilinear, sickle (dome-shaped), or irregular echo arising from the interventricular septum and bulging toward the right ventricle in systole was visualized in all patients. This finding was detected in 7 of 8 long axis views, 5 of 8 short axis views, 5 of 7 apex four-chamber views, and 4 of 7 subcostal four-chamber views. In addition, real-time cross-sectional echocardiograpic studies were performed in 40 patients with angiographically proven membranous ventricular septal defect without AVS; in only one patient was the abnormal echo suggesting aneurysm of the ventricular septum detected in the long axis and apex four-chamber views. Our echo study suggests that two-dimensional echocardiography has acceptable specificity for the diagnosis of AVS.

Child↗
PubMed1981

Digital video subtraction angiography of renal vascular abnormalities.

A digital subtraction system for performing intravenous angiography has been developed and applied to the diagnosis of renal vascular abnormalities. A total of 35 patients underwent 39 intravenous angiographic examinations for a variety of renal-related clinical indications. Satisfactory examinations were achieved in 36 cases (92%) with a high degree of diagnostic accuracy. Digital video subtraction angiography is an outpatient procedure that is accurate, safe, and inexpensive to perform.

Adult↗
PubMed1981

Factors affecting real-time, cross-sectional echocardiographic imaging of perimembranous ventricular septal defects.

Recent studies suggest good prospective accuracy for two-dimensional echocardiographic imaging of ventricular septal defects (VSD). We obtained two-dimensional images with high-frequency, high-resolution scanners from 36 patients proved by cardiac catheterization to have perimembranous VSD. In 20 patients, the VSD was an isolated lesion and in 16 it was associated with other forms of heart disease. VSDs were imaged in long-axis, apical four-chamber and subcostal echocardiographic views. The smallest VSD imaged was 2 mm in diameter on echo; the largest, 23 mm. The imaged size of VSDs was larger at end-diastole than at end-systole by paired t test on all views (all p less than 0.005). VSD size also varied between views, with no predictive relationship except between apical and subcostal four-chamber views in diastole (r = 0.71, p less than 0.005). This agreed with qualitative direct observations of an ellipsoid or irregularly shaped VSD in operated patients. Echocardiographically measured VSD size normalized for either aortic root size or for patient weight could be used to separate isolated VSDs with large shunts (Qp/Qs greater than 2:1) from those with small shunts. Review of 250 two-dimensional echocardiographic studies from patients proved not to have a VSD revealed 28 planes of imaging with false-positive VSD. None of the false-positive VSDs was imaged consistently on all views. Additionally, a "T" artifact (broadening of septal edges around a VSD) has been found to be a reliable marker of true VSD imaging. To best quantify VSD size and to avoid false-positive diagnoses, it is necessary to use multiple views and to consider the marked changes in VSD size that occur between diastole and systole.

Adolescent↗
PubMed1981

Digital video subtraction angiography: screening technique for renovascular hypertension.

Significant deterrents to the detection of renovascular hypertension are the unreliability of current screening methods and the widespread belief that the incidence of renal artery stenosis is too low to justify the expense and morbidity of routine angiography. We have developed a new imaging method, digital video subtraction angiography, suitable for screening outpatients for renal artery lesions. It involves injecting a 45 cc bolus of contrast medium through a venous catheter. Instead of exposing x-ray film, images are recorded directly on an image intensifier, digitized, and stored in a computer that electronically subtracts, reconstructs, enhances, and magnifies the images on a video screen. Renal parenchymal vessels less than 1 mm in diameter can be seen. So far, 45 studies have been performed in 39 hypertensive patients. Images of diagnostic quality were obtained in all except one. Renal artery stenosis was revealed in 15 patients, renal artery occlusion in two, diffuse intrarenal arterial narrowing in two, atrophic kidney with small renal arteries in two, and normal renal vessels in 23. Digital video subtraction angiography is an inexpensive, cost-effective, safe, and accurate method for renovascular hypertension screening and for evaluating patients after surgical correction of renal artery stenosis.

Angiography↗
PubMed1980

Intravenous angiography using digital video subtraction: x-ray imaging system.

An x-ray imaging system, using digital subtraction techniques, has been developed. The system requires: (1) high output generation equipment; (2) an image intensifier capable of receiving high output exposures, 1 mR (2.58 X 10(-7) C/kg) at the face of the intensifier, without loss of either contrast or resolution; (3) a precision digital video camera; (4) processing computer with sufficient storage capacity; and (5) digital image storage. With this system it is possible to visualize the major arteries after intravenous contrast injection. The system, angiography technique, and early results are described.

Angiography↗
PubMed1980

Intravenous angiography using digital video subtraction: intravenous cervicocerebrovascular angiography.

The clinical application of intravenous angiography to study the cervicocerebrovascular system using the digital video subtraction system described in a companion article is reported. About 0.75 ml/kg of a standard 76% iodine contrast solution is injected into an antecubital vein using a power injector. Then 15-20 exposures of the head and neck region at a 1/sec rate are made on the image intensifier. The images are recorded by a high performance video system and the output signal is digitized for subsequent computer manipulation. The subtraction images of these vessels produced by the computer show the vessels clearly, even though they contain very low concentrations of contrast media. Standard exposure factors of 75-80 kVp, 9-10 msec at 800-1,000 mA are used. Clinically pertinent features of the data alteration and flow through the system and the step-by-step computer procedures used to achieve and analyze the various forms of subtracted images are described. Five experimental and clinical cases demonstrate appropriate applications to cervicocerebrovascular disease: (1) evaluating the effects of surgical and medical therapy on atherosclerosis; (2) providing a screening angiographic test for patients with asymptomatic bruits and/or positive noninvasive studies; (3) evaluating patients who have significant generalized vascular disease either precluding or presenting hazardous contraindications to transarterial catheterization; (4) evaluating significantly aged patients in whom standard angiography has higher risk; and (5) evaluating currently asymptomatic patients who are medically at higher risk for developing atherosclerotic lesions. Numerous examples of the various types of image manipulations are presented: (1) linear subtraction; (2) logarithmic subtraction; (3) alterations of electronic contrast enhancement (map slope); (4) the usefulness of a series of angiographic images; and (5) the importance of multiple projections with this technique.

Aged↗
PubMed1977

Suprasternal notch echocardiography. Assessment of its clinical utility in pediatric cardiology.

Echocardiographic suprasternal relationships of the transverse aortic arch (TAA), right pulmonary artery (RPA) and left atrium (Y' LAD) were validated and angiographic-echocardiographic measurement correlations were made for each structure. Normal values were determined with respect to body surface area. In normals, regardless of age or body size, mean dimensional TAA/RPA ratio was 1.2:1 and Y' LAD equaled the anterior-posterior, or Z axis, left atrial dimension (Z LAD)- TAA/RPA ratio was increased in aortic stenosis and tetralogy of Fallot and was decreased in ventricular septal defect, atrial septal defect and pulmonary stenosis. Ratio did not correlate with lesions severity as assessed by cardiac catheterization except in pulmonary stenosis. Discrepant Y' LAD values (usually increased Y' LAD and decreased Z LAD) occurred in children with various forms of heart disease. Some had sternal compression but others had normal chests. Children with pectus excavatum showed similar compression. These findings underscore the need for incorporation of a suprasternal examination into the standard echocardiographic examination of children.

Adolescent↗
PubMed1977

Left sided segmental portal hypertension following mesocaval interposition shunt.

Following a mesocaval interposition shunt in three patients with cirrhosis of the liver, bleeding esophageal varices recurred in two and left sided portal hypertension partially persisted in one patient. Angiographic and pressure studies of the portal system demonstrated effective decompression of the greater splanchnic venous system but continued lesser splanchnic venous hypertension. Recurrent variceal hemorrhage ceased following splenectomy done as an emergency. In contrast to a standard portacaval shunt, it is suggested that after an interposition mesocaval shunt, altered jet streaming of mesenteric blood flow may divert gastrosplenic venous drainage away from the interposition shunt with persistence of lesser splanchnic venous hypertension. Recognition of this entity and of the need for splenectomy is advocated.

Adult↗