Biomedical subjects
T Roeren
Publications and source records attributed to T Roeren.
Intraarterial digital subtraction angiography of renal transplants.
Nineteen renal allograft recipients with suspected vascular pathology of the graft were examined by digital subtraction angiography combined with intraarterial catheter technique. Image quality was excellent and diagnosis was definite in all cases. Dosages of contrast medium are reduced to a minimum (1.5 g iodine/patient) and the risk of nephrotoxic side effects is virtually negligible with this technique.
[Differential diagnosis of changes in density and structure of the foot bones].
Skeletal disorders of the foot can be assessed radiologically by changes in bone density, structure and/or form. The knowledge of specific morphological criteria is a precondition for differential diagnosis. Our classification of skeletal disorders of the foot is based on the specific signs that can be observed in systemic and local diseases affecting the pedal bones.
[Duplication of the external iliac artery].
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[Intra-arterial DSA for control of aortocoronary bypass--an alternative to coronary angiography].
Intraarterial DSA is a suitable method for early postoperative control of coronary artery bypass grafts. Small quantities of contrast media with low iodine content are injected into the aortic root. Investigations can be carried out with a routine fluoroscopic and digital equipment; additional cine-technique and analogue memory disc are not necessary. At an image rate of 3/s the bypass anastomoses can be exactly visualized in 75%, whereas diagnostic information was not sufficient in only 4% of all cases. The use of modern F-5-catheters and the nonselective injection make this method a less invasive alternative to coronary angiography. It is particularly useful in evaluation of short- and long-term results.
[Improvement of arteriography technics by new thin catheters].
New, small, polyurethane French 4 and French 5 sized catheters with a commensurately large lumen are described. In combination with DSA they allow low doses of contrast media in renal insufficiency and facilitate selective and superselective manipulations. The high flow specification also permits use in "conventional" angiography.
[Lung metastases--limitations and possibilities of radiologic diagnosis].
The different sensitivities of chest radiograph, full-lung tomography and computed tomography (CT) are determining factors in the diagnosis of pulmonary metastases. Pathogenesis and pathologic-anatomical morphology explain the radiological findings. Knowledge of spontaneous or therapy-induced changes and "sterilized" metastases is important for follow-up studies. The precise densitometry in CT improves the assessment of degree of a pulmonary disk-shaped lesion. Histological diagnosis may be obtained by fluoroscopically guided percutaneous thin-needle biopsy.
[Digital subtraction angiography in Swyer-James syndrome].
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Lack of a diurnal plasma adenosine 3',5'-monophosphate rhythm.
Plasma cAMP levels were measured using a protein-binding radioassay in nine healthy volunteer subjects over a period of 24 h under standardized conditions and also after an hour of orthostatism. No circadian variations of cAMP in plasma were observed. After orthostatism, however, there was a significant rise in cAMP concentrations.
TNM staging of gastrointestinal tumors by hydrosonography: results of a histopathologically controlled study in 60 patients.
BACKGROUND: The study is a prospective evaluation of preoperative TNM staging of gastrointestinal tumors by hydrosonography (HUS). METHODS: Sixty patients with suspected gastric or colorectal cancer underwent HUS for TNM staging. All patients were operated on and the tumors completely removed when possible. HUS findings were correlated with histopathologic staging. RESULTS: HUS correctly localized tumors in 75% of patients. T stage accuracy was low for gastric cancers (41%). N staging of gastric cancers was accurate in 68% of all cases and was highly specific (100%). Staging was more accurate for colorectal tumors (70%), especially with respect to infiltration of other structures (sensitivity 100%, specificity 95%). N staging, however, was not reliable, mostly owing to impaired examination conditions. CONCLUSION: HUS easily misses tumors of the gastric cardia and distal part of the rectum. T staging of colorectal tumors with HUS is highly accurate, reaching 92% if the tumor is localized. T1 cancers of the stomach tend to be overstaged, and serosal infiltration by gastric cancers is often misjudged. With the exception of cardial gastric and distal rectal cancers, HUS comes close to endosonography for staging gastrointestinal tumors. HUS does not require intraluminal access.
MRI for staging of gastric carcinoma: first results of an experimental prospective study.
PURPOSE: Our goal was to define the accuracy of MRI in the staging of gastric carcinomas. METHOD: Twenty consecutive surgical specimens were imaged immediately after gastrectomy for gastric carcinoma. Imaging was performed with a 1.0 T imaging system. T1-weighted, T2-weighted, and opposed phase images were acquired and analyzed for tumor infiltration of the gastric wall and the presence of perigastric lymph nodes. T and N stages were classified according to the International Union Against Cancer classification. Finally histopathologic staging of the specimens was compared with staging by MRI. RESULTS: In gastric specimens, three to five layers of the gastric walls were visible. There were typical signal intensity patterns on T1-weighted, T2-weighted, and opposed phase images. Tumor diagnosis and lymph node detection were best achieved by opposed phase imaging. Nineteen of 20 (95%) carcinomas were localized by MRI; T staging accuracy was 65%. The sensitivity to detect metastatic lymph nodes was 87%, specificity 60%. N staging accuracy (nodes positive versus negative) was 80%. CONCLUSION: High resolution MRI of gastric tumors is possible ex vivo. MRI enabled differentiation of up to five layers of the gastric wall, and therefore staging of gastric carcinomas is technically possible. However, to evaluate the exact role of MRI as a staging tool of gastric carcinomas, a correlation between MR morphology and the histologic structure of the gastric wall has to be achieved first.
Adenosine and diltiazem. A new therapeutic concept in the treatment of intestinal ischemia.
To determine the therapeutic effect of two vasodilators, adenosine and diltiazem, in mesenteric ischemia, 13 dogs were treated with an intra-arterial perfusion of the drugs after digitalis intoxication. Blood flow was restored to the control value after a dose of 2 micrograms/kg/minute adenosine or 5 micrograms/kg/minute diltiazem. The advantage of adenosine is that its effect begins and ends very rapidly, but because doses of more than 2 micrograms/kg/minute may cause a drop in blood pressure, strict pressure control is mandatory when the drug is applied clinically. Its limited use is appropriate, for example, when operative measures cannot be excluded. Diltiazem can be used for long-term therapy with a reduced risk of a drop in blood pressure.