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Biomedical subjects

A Formanek

Publications and source records attributed to A Formanek.

At least 19 recordsLinked to original sources

Noninvasive localization of the aortic arch in infants with tracheoesophageal fistula: an experimental study.

For surgical treatment of patients with tracheoesophageal fistulas the localization of the aortic arch is great practical importance. Aortography and CT scanning have been advocated as the radiographic techniques of choice. The location of the aortic arch can be diagnosed on a chest x-ray by the deviation of the trachea alone. A barium swallow is not required. The optimal radiographic technique for this purpose was investigated in phantom studies and tested in animals and newborns. It is proposed that in addition to the standard chest x-ray a high kvp film with hardened beam (1 mm copper -- 1 mm aluminum) be added in order to demonstrate the tracheal deviation. The additional x-ray exposure to the infant is negligible; and the technique is simple, reliable, and noninvasive.

Animals

The multiple faces of fibromuscular dysplasia of the renal arteries.

For surgical treatment of patients with FMD of the renal arteries an optimal angiographic study is necessary. Preferably aortography as well as selective magnification renal angiography should be carried out. Oblique views may be necessary to demonstrate the peripheral extension into segmental branches, collateral circulation, the presence of aneurysms, and/or associated complications as AV fistulas, infarctions, intramural hematomas and pseudoaneurysms.

Adolescent

Coarctation of the abdominal aorta.

Coarctation of the abdominal aorta is an uncommon process but an important cause of systemic hypertension. Angiography is the investigation of choice to establish a diagnosis and document the extent of involvement. However, angiography does not provide an etiological diagnosis; and it may not be possible to distinguish an acquired coarctation from a congenital process. Three patients with coarctation of the abdominal aorta are presented.

Adolescent

Primary liver tumors in the pediatric age group: an angiographic challenge.

Eleven children, ranging in age from three months to fifteen years, with primary liver tumors were examined by large volume direct magnification arteriography (2.5--3 ml of contrast material per 1 kg body weight for a single selective study). The following tumors were found: hepatoblastoma (1), hepatocellular carcinoma of the adult type, hepatoma (3), infantile hemangioendothelioma (4), hemangiosarcoma (1), focal nodular hyperplasia (1) and cystic mesenchymal hamartoma (1). Some of the tumors have a quite typical angiographic appearance as infantile hemangioendothelioma, hemangiosarcoma, cystic mesenchymal hamartoma. The other highly vascular neoplasms show unspecific signs of vascular malignant tumors; subtile angiographic signs may, however, be present and help in the differential diagnosis.

Adolescent

Radiological evaluation of composite aortic grafts.

Aneurysm of the ascending aorta with aortic regurgitation is most commonly caused by cystic medial necrosis. Replacement of the aortic valve and diseased aorta with a composite graft and re-implantation of coronary arteries is the surgical treatment of choice at the authors' institution. The most important late complication of this procedure is hemorrhage at the anastomotic sites. Radiology plays an important role in the management of these patients. The angiographic appearance of cystic medial necrosis and the radiological features and postoperative complications of composite grafts in 15 patients are described.

Adolescent

The "ring sign" of necrotic pheochromocytoma.

Pheochromocytomas are usually hypervascular tumors exhibiting dense stain during angiography. The cystic nature of the neoplasm or tumor necrosis can result in failure of opacification of the mass or a central lucent area. Four cases of pheochromocytoma are described where a central avascular zone was surrounded by a dense rim of contrast, giving a "ring sign." Since this appearance is best seen in the capillary and venous phases, delayed films are essential.

Adolescent

An essential view in coronary arteriography.

A significant stenosis of the left main coronary artery is associated with a significant mortality and is one of the major indications for aortocoronary bypass surgery. The diagnosis of this lesion on clinical grounds is inconsistent and should be established by angiography. All routine projections during coronary arteriography cause foreshortening of the left main coronary artery. Well-collimated anteroposterior and shallow right and left anterior oblique views show the main segment best. These views also show the proximal segments of circumflex and anterior descending branches, and should be routinely used during every coronary arteriogram.

Coronary Angiography

Complications of wedge hepatic venography.

During wedge hepatic venography, mechanical injection should be accomplished at the lowest possible rate in order to avoid hemorrhagic infarction. Small amounts of contrast material should be administered. Hepatic angiography may result in an area of tumor blush at the site of a previous wedge injection.

Animals

A new, simple test for renin sampling.

In 8 of 18 patients with suspected diagnosis of renovascular hypertension, the resting renin values were inconclusive. However, following tourniquet stress, the values became positive. Sixteen of 18 patients showed significant decrease in blood pressure following surgery. The procedure was well tolerated, and its routine use is recommended.

Adolescent

Three year experience with percutaneous introduction of inferior vena cava filter.

Fifteen patients with recurrent pulmonary embolism were treated with a Mobin-Uddin umbrella filter (UF) introduced percutaneously via femoral vein. There were not technical difficulties, bleeding, or migration of the UF. The incidence of lower extremity edema or phlebitis was not higher than in patients with transjugular application of the UF or in patients with surgical inferior vena cava clipping. Two patients had fatal recurrent pulmonary embolism: in one of them the UF was positioned correctly in the vicinityof the renal veins; in the second the UF was placed too low and a large clot may have formed proximal to the UF. The transfemoral approach of the UF insetion represents a significant simplication of the inferior vena caval interruption, but it can only be used if thrombi are excluded by venography in the iliac vein and inferior vena cava. The UF should be placed as close as possible to the orifices of the renal veins to prevent a thrombus formation proximal to the filter.

Adolescent

Peripheral angiograph enhancement by long leg pneumatic boots.

In patients with arterial occlusive disease it is virtually impossible to predict the speed of blood flow due to the presence of stenoses, occlusions, and collaterals. Repeated exposures and injections can be avoided by the use of pneumatic boots which increase peripheral blood flow by reactive hyperemia, are well tolerated by patients, and decreases the pain associated with injection of contrast material.

Angiography

Comparison of ejection fraction calculated by nine different volume calculation methods.

Single plane right anterior oblinque ventriculography was performed on 25 patients with normal left ventricular contraction and on 25 with left ventricular akinesia or dyskinesia. The value of the left ventricular ejection fraction (EF) was calculated by 9 different methods, including a new one utilizing the mathematical model of a cone. All methods tested were appropriate for inter-group comparisons of EF. For inter-individual comparisons, however, only those methods described by Davila, Chapman, Dodge, Beranek, and our new method, are appropriate.

Angiocardiography

Hemodynamic assessment of obstructive aortoiliac disease.

Angiographic demonstration of obstructive aortoiliac disease is of paramount importance prior to surgery. Obstructive disease in the femoral popliteal system can only be surgically relieved if inflow is adequate. Severely stenotic lesions may be missed by angiography due to the oblique course of the iliac arteries and inability to obtain right angle views. Translumbar downstream catheterization of the abdominal aorta and puncture of both femoral arteries allows simultaneous pressure recordings. The injection of 30 mg of papaverine into the femoral artery assures maximal vasodilatation mimicking conditions under exercise. A minimal gradient at rest may become obvious following the injection of papaverine, indicating hemodynamically significant disease and warranting surgical correction. The technique has proved to be simple and valuable, and there have been no complications.

Aorta, Abdominal