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Biomedical subjects

S R Reuter

Publications and source records attributed to S R Reuter.

At least 19 recordsLinked to original sources
PubMed1990

Antitrust principles for radiologists.

As the practice of medicine becomes more competitive, the states' attorneys general, the Federal Trade Commission, the Justice Department, and individual competitors progressively will use the Sherman Antitrust Act to ensure a competitive market for the delivery of health care services. Therefore, radiologists must have an understanding of the purposes of the Sherman Act and an understanding of types of anticompetitive activities that will trigger civil and criminal penalties. Specifically, radiologists must avoid blatant violations, such as price fixing, division of markets, and group boycotts, any of which may elicit the interest of the Justice Department. Further, radiologists need to consult knowledgable legal counsel when carrying out peer review activities and when entering into exclusive contracts with hospitals, particularly hospitals that have significant market power.

Antitrust Laws↗
PubMed1989

Nonselective digital subtraction angiography. Compact contrast material bolus for improved image quality.

Digital subtraction angiography (DSA) examinations of major aortic branch vessels traditionally have been performed with aortic injections of dilute contrast material (70-150 mg I/mL) over approximately 2 seconds. This study examines a technique employing rapid boluses of undiluted contrast material (282-300 mg I/mL) in small volumes and compares the quality of the images to those obtained using conventional methods. Twenty intra-aortic DSA angiograms of the renal arteries were performed in 10 patients. In each patient, both compact bolus and conventional injections were performed. Injections of 12 or 15 mL of diatrizoate meglumine-60% at 30 mL/second (duration = 0.4 or 0.5 seconds) were compared with injections of 24 or 30 mL of diatrizoate meglumine-30% at 12 mL/second (duration = 2 seconds). Aside from injection technique and image projection, no other variables were altered, and the iodine loads were the same for the two injections in each patient. The images were paired and rated by four radiologists without knowledge of the technical parameters. The radiologists overwhelmingly preferred the images corresponding to the compact bolus technique (Chi-square analysis P less than .001). Visualization of the main renal arteries and the intrarenal branches was improved (P less than .001 for both). A reduction in misregistration artifact is suggested but not statistically significant. We conclude that image quality in nonselective, intra-arterial DSA can be improved without an increase in iodine dosage by the rapid administration of undiluted contrast material in small volumes.

Adult↗
PubMed1987

Balloon-expandable intracoronary stents in the adult dog.

We studied the acute and chronic biological reaction to balloon-expandable intracoronary stents in the adult dog. Twenty stainless steel stents were placed, by standard angioplasty techniques, into the left anterior descending, left main, or circumflex coronary arteries of 20 dogs. Angiography was performed at 1, 3, 6, and 12 months and animals were killed in groups of three at 1, 3, 8, and 32 weeks, for gross, light, and electronmicroscopic analysis. All dogs survived, all stents were patent, and there was no evidence of myocardial infarction, spasm, rupture, or aneurysm formation during follow-up (longest 18 months; average, 12 months). The stent was initially covered by a thin layer of thrombus that was replaced later by neointimal muscular proliferation that reached its maximal thickness by 8 weeks (p less than .01). This neointima gradually thinned as it became more sclerotic and less cellular. The stents were covered completely by immature endothelium by 1 week without loss of side branches. We conclude that balloon-expandable intraluminal stents can be safely placed percutaneously into normal canine coronary arteries. Because of rapid endothelialization high patency rates can be expected, thus offering promise for clinical applications in man.

Angioplasty, Balloon↗
PubMed1987

An overview of informed consent for radiologists.

Because of the procedure-oriented nature of their specialty, radiologists obtain informed consent from patients daily. This paper attempts to help the radiologist obtain informed consent without incurring malpractice liability by discussing the important legal concept of simple consent as distinguished from informed consent, the elements a patient must prove to succeed in court with an allegation of lack of informed consent, the varying state requirements about the amount of information the patient must be given, the persons who must obtain consent from the patient, and the persons who can give consent for the patient. Consent for IV injections of contrast medium and consent forms are discussed because of the current controversy on these subjects. Courts and state legislatures have usually addressed only specific aspects of informed consent. However, except for the amount of information that must be given the patient, the courts have been relatively uniform in their requirements. Therefore, it is likely that a state court faced with issues of informed consent about which no law exists in their own state will use the existing law in other states as a precedent and adopt similar rules. However, each radiologist must be familiar with the specific rules for informed consent that have been developed by the courts and legislatures in the state in which he or she practices.

Contrast Media↗
PubMed1986

Trauma of the extremities: prospective comparison of digital and conventional angiography.

Digital subtraction angiography (DSA) and conventional film angiography (CFA) were compared prospectively in 50 patients with trauma of the extremities. Each patient underwent both procedures with comparable imaging parameters and injections. Three angiographers reviewed the angiograms for the presence of seven angiographic signs of arterial injury. The two modalities showed pseudoaneurysms, arteriovenous fistulas, vessel displacement, occlusion, and focal narrowing equally well. CFA was superior to DSA in delineating intimal dissection; DSA was better for demonstrating extravasation. Clinical follow-up demonstrated that both procedures had a sensitivity of 100%; the specificity was 94% for DSA and 97% for CFA. Neither procedure produced a false-negative result.

Angiography↗
PubMed1986

Atherosclerotic rabbit aortas: expandable intraluminal grafting.

Balloon-expandable intraluminal grafts that ranged in diameter from 2 to 4 mm were placed in the atherosclerotic abdominal aortas of 24 rabbits. The animals were killed 1, 3, 8, or 24 weeks after placement of the graft. All grafts retained patency without altering the luminal diameter. The small degree of neointimal thickening covering the graft's inner surface was not detectable on conventional in vivo arteriograms. Aortic atherosclerotic plaque external to the graft was markedly compressed 1 week after graft placement. The plaque regained full thickness 24 weeks after grafting when the plaque expanded outside the graft as a result of relaxation or atrophy of the surrounding arterial media.

Angioplasty, Balloon↗
PubMed1986

Expandable intraluminal vascular graft: a feasibility study.

An expandable intraluminal graft mounted coaxially over an angioplasty balloon catheter was used in dog arteries. The graft, a wire mesh tube that has the ability to retain its expanded shape, opposes elastic recoil of the arterial wall after maximum balloon inflation. Eighteen grafts were placed in the abdominal aorta and iliac femoral, renal, superior mesenteric, and carotid arteries of eight dogs through femoral or carotid arteriotomies. Two grafts were placed in areas of artificially induced stenosis, completely restoring the lumen. Overall patency rate at 35 weeks was 77%. Histopathologic examination of patent grafts showed complete endothelialization at 3 weeks. The smaller caliber grafts and those that had outflow obstruction showed significant degrees of intimal hyperplasia.

Angiography↗
PubMed1985

Expandable intraluminal graft: a preliminary study. Work in progress.

To overcome the problem of recurrence of stenosis after vascular balloon dilatations, we developed an expandable, intraluminal graft that allows dilatation of the lesion and simultaneous placement of a supportive endoprosthesis to prevent recoil of the arterial wall. The graft is made of continuous, woven, stainless steel wire. The resulting tubular mesh has a wall thickness of 200-450 micron and 80% open surface. The grafts, mounted on angioplasty catheters, are introduced through 8-12-F Teflon sheaths. Eleven grafts of 6, 8, and 10 mm in diameter by 20 mm long were placed in the aorta, common carotid, superior mesenteric, iliac, and renal arteries of dogs. Six grafts showed no stenosis in follow-up studies of up to 8 weeks. Two grafts had moderate stenosis as a result of neointimal hyperplasia. Two partial and one complete graft thrombosis occurred in nonheparinized animals in which the graft outflow was restricted. Anticoagulant was not used on a long-term basis. Light and electron microscopy studies showed complete covering of the graft's inner surface by endothelium at 3 weeks.

Angioplasty, Balloon↗
PubMed1978

External iliac artery fibrodysplasia.

Clinical and arteriographic features of 12 patients with external iliac artery fibrodysplasia are reviewed. These lesions usually occur in patients having arterial fibrodysplasia elsewhere, attesting to the fact that they represent a generalized arteriopathy. Occasionally they occur in association with severe atherosclerosis. External iliac artery fibrodysplasia exhibits the classic corrugated "string-of-beads" angiographic appearance in the majority of patients. The pattern of aneurysmal dilatation of the external iliac arteries in one patient and the aorta and common iliac and internal iliac arteries in another with diffuse arterial fibrodysplasia has not been previously reported. Three patients had symptoms directly referable to external iliac artery fibrodysplasia. The lesions may be symptomatic when the arterial lumen is sufficiently compromised to reduce blood flow or when superimposed thrombosis and/or embolization occurs.

Adult↗