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Biomedical subjects

H A Baltaxe

Publications and source records attributed to H A Baltaxe.

At least 19 recordsLinked to original sources
PubMed1985

Videodensitometric quantitation of stenosis: in vitro and in vivo validation.

Percentage of stenosis of a vascular lumen was quantitated using a digital subtraction angiography system with videodensitometric analysis. To validate the algorithm and methods, we used precisely drilled Lucite rods of three inner diameters and various reduced diameters to give known luminal reduction. Both in vitro and in vivo results of stenosis measurements resulted in an excellent correlation between actual and measured values (correlation coefficient greater than 0.9 for all trials). Consistent underestimation of stenosis of about 5% was attributed to the various image degradations inherent with the imaging procedure and equipment. Errors were greatest with midrange stenoses and less at the extremes of the lesion values. An insufficient signal-to-noise ratio was caused by low photon flux and/or low contrast material concentration and overlying vasculature filled with contrast material. Overall, the videodensitometric technique is accurate, easy to implement, objective, and relatively free of errors associated with the geometric/edge detection method.

Absorptiometry, Photon↗
PubMed1985

Acute pancreatitis.

The exocrine pancreas secretes into the gut on demand more than 20 proteins that are indispensable for digestion. In-vivo autodigestion is prevented by an array of natural safeguards. In acute pancreatitis, inappropriate intrapancreatic activation and release of pancreatic hydrolases occur, but the pathogenetic mechanism of autodigestion is unclear. The release of proteases, lipase and colipase, phospholipase A, vasoactive peptides, and other agents probably accounts for the edema, tissue destruction, fat necrosis, metabolic abnormalities, and complications. Ethyl alcohol abuse, gallstones, trauma, and other common and rare conditions can induce pancreatitis. The patient's outcome can be predicted by certain prognostic signs. Ultrasonography and computerized tomography are invaluable diagnostic tools and magnetic resonance imaging appears promising. Hemodynamic monitoring, intensive care with colloid and crystalloid infusions, correction of electrolyte abnormalities, judicious use of antibiotics, peritoneal lavage, drainage of pancreatic exudation fluids, and surgical intervention require a team approach, especially in patients with multiple complications. Additional research is needed into the pathogenetic mechanism of autodigestion and the design of specific therapies.

Abscess↗
PubMed1984

Multipurpose coaxial needle used for percutaneous nephrostomy.

We describe a 24-cm long coaxial needle that has a 15-cm, beveled outer sleeve and accepts a 0.038-inch (0.097-cm) guidewire. A Luer-loc fastens the outer needle to the inner one. The outer sleeve has markings etched 1 cm apart to indicate the distance from the tip of the inner needle and that of the outer sleeve. This needle was designed to be used for percutaneous nephrostomy, particularly in the infant and in nondilated urinary systems.

Needles↗
PubMed1983

Comparative hemodynamic effect of metrizamide and Renografin 76 in infants with congenital heart disease.

Twenty patients under the age of 2 years with suspected congenital heart disease received alternately Renografin 76 and metrizamide for angiocardiography. The dose was 2.0 ml/kg per injection for both contrast media into the left ventricle. Metrizamide induced slightly lesser change in heart rate, peak systolic pressure, and peak end-diastolic pressures. Serum osmolality, hematocrit, and serum electrolytes were affected equally by the contrast media. Metrizamide was well tolerated by the neonates with congenital heart disease and its radiopacity was adequate for diagnostic purposes. At the doses administered, metrizamide does not seem to have any great advantage over Renografin 76 for angiocardiography in infants with severe congenital heart disease.

Angiocardiography↗
PubMed1983

Percutaneous transluminal carotid angioplasty in fibromuscular dysplasia. Case report.

A patient with fibromuscular dysplasia (FMD) of the internal carotid artery was treated by balloon percutaneous transluminal angioplasty (PTA). This is the sixth reported case of FMD stenotic disease which was dilated by PTA. All previous cases including the current example were treated successfully with resolution of symptoms. This procedure is associated with a relatively low morbidity and is an alternative method of treatment to operative endarterectomy for this disorder.

Adult↗
PubMed1982

Imaging of the left ventricle in patients with ischemic heart disease: role of the contrast angiogram.

The contrast left ventriculogram is the gold standard against which all other cardiac imaging techniques are measured. In the past decade, noninvasive methods such as radionuclide angiography, echocardiography, computed tomography (CT), and digital substraction imaging have become available. This review examines the role of these techniques, and whether they will supersede the selective contrast ventriculogram. Each of these modalities seems to have specific capabilities and superiority in a certain area. Contrast ventriculography is best suited for the functional assessment of the left ventricular wall. Isotopes and CT have great potential for evaluating the myocardium properly. Echocardiography produces good visualization of atrioventricular valves and intracavitary structures. The role of contrast angiography is considered in the workup of the cardiac patient. The contrast angiogram is closely related to the coronary angiogram in the assessment of the patient with arteriosclerotic heart disease and it is still a necessity for the preoperative evaluation of the patient with congenital heart disease.

Angiography↗
PubMed1981

Therapeutic embolization of the renal artery with Gianturco coils: limitations and technical pitfalls.

The Gianturco coil, with or without Gelfoam, is particularly popular and effective in occluding renal arteries to control bleeding, devascularize tumors, close arteriovenous fistulas, and infarct kidneys in end-stage renal disease. However, without special precautions, successful embolization can suddenly be transformed into catastrophe. Representative reports of complications from medical centers across North America are used to illustrate the initial technical pitfalls of coil placement, as well as the more delayed complications that produce deviations from the usual postinfarction syndrome.

Abscess↗
PubMed1980

Diagnosis and treatment of fluid-filled renal structures in children with ultrasonography and percutaneous puncture.

The application of ultrasonographic and percutaneous needle puncture techniques in the diagnosis of various fluid-filled renal anomalies has permitted rapid delineation of anatomic detail, more definitive physiologic evaluation, and drainage, when necessary, in a safe and cost-effective manner. Its usefulness in children is emphasized in 6 illustrated cases of male infants with minimally or nonopacified renal anomalies, one of the more difficult diagnostic problems in pediatric urology.

Adolescent↗
PubMed1980

Assessment of healing of long-bone fractures by intraosseous venography.

Intraosseous venography with compression of the soft tissue was performed following fracture of the radius in 13 dogs to assess the repair process. Two angiographic criteria were analyzed: (a) intraosseous venous crossing of the fracture ("medullary crossing") and (b) capillary blush of the proximal osseous fragment ("proximal blush"). The bone strength of the fractured and intact radii was compared. Venograms obtained immediately after fracture showed contrast material reaching but not crossing the fracture line, indicating that the entire intramedullary venous network had been disrupted. When Parafilm was interposed between the bone fragments to prevent healing, proximal blush was seen at 4 weeks and medullary crossing at 6-7 weeks; bone strength was 13-14% of normal. With no barrier, proximal blush appeared at 5 weeks and medullary crossing at 10-11 weeks; bone strength was 30-40% of normal. The authors conclude that medullary crossing can be seen in the presence of decreased bone strength if the healing process is uneven across the fracture line, as occurred with Parafilm. If the animal model reproduces the clinical situation, this finding challenges the predictive value of intraosseous venography.

Animals↗
PubMed1980

Role of peripheral vasodilation in the hypotensive response to left ventriculography in anesthetized dogs.

Hypotension after left ventriculography (LVG) is believed to result from direct myocardial toxicity, peripheral vasodilation, or a combination of both. The contribution of each has not been established. Thus, LVG was performed in anesthetized dogs under conditions in which peripheral vascular reactivity (PVR) was altered pathophysiologically (aortic coarctation) or pharmacologically (acetylcholine infusion). Ventricular pressure (LVP), its first derivative (dP/dt), aortic pressure (AoP), and carotid and femoral flows were monitored. When PVR was normal, LVG was associated with significant hemodynamic changes which reached a maximum 25-35 seconds after injection. Left ventricular and aortic diastolic pressures were decreased by 22 and 48%, whereas carotid and femoral systolic flows were increased by 41 and 59%. During acetylcholine infusion, LVG did not cause systolic hypotension and peripheral flows were maintained strikingly constant. Similarly, LVG also was associated with insignificant changes in systolic pressures and carotid flow in the presence of aortic coarctation. These results demonstrate that the hypotension attendant with LVG is directly related to the augmentation in peripheral flow, suggesting that the response is mediated almost exclusively by peripheral vasodilation.

Acetylcholine↗
PubMed1979

Pitfalls in the plain film evaluation of the thoracic aorta: the mimicry of aneurysms and adjacent masses and the value of aortography. Part I. Transverse aortic arch.

In five instances, transverse aortic arch aneurysms were found that had initially, clinically and radiographically, mimicked thoracic neoplasms. Transverse aortic arch aneurysms display a wide spectrum of presentation: they may be asymptomatic, or they may cause symptoms secondary to esophageal, bronchial, vascular, or neural compression within the mediastinum and so mimic neoplasms. Conventional radiography in four projections and tomography are important components of the diagnostic evaluation of middle mediastinal masses. However, because plain film analysis is unable confidently to distinguish selected uncalcified aortic arch aneurysms from neoplasms, thoracic aortography is essential to the diagnosis.

Adult↗
PubMed1979

Reliability of doppler scanning of the carotid bifurcation: angiographic correlation.

The results of continuous wave Doppler scanning of 96 common carotid arteries and their immediate branches were compared with those of selective angiography. The overall accuracy of the Doppler technique for the assessment of the common, internal and external carotid arteries was 98%, 81% and 86%, respectively with a sensitivity of 60%, 70% and 54%, and a specificity of 100%, 93%, and 96%. When stenoses of 50% were considered hemodynamically insignificant, the overall accuracy of the assessment of the common, internal and external carotid arteries rose to 100%, 93% and 93%, but the sensitivity was only 100%, 83% and 53%, whereas the specificity was 100%, 96% and 96%. This modality did not prove useful in the detection of intimal ulcers and plaques nor could the degree of stenosis be accurately graded. The above data indicate that contrast angiography remains imperative prior to surgery.

Angiography↗