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Biomedical subjects

C Claussen

Publications and source records attributed to C Claussen.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Intravenous administration of contrast medium during computed tomography (CT) of the operated lumbar spine].

In 35 patients with recurrent radicular complaints which occurred 4 weeks to 38 months after operation for lumbar disc herniation, the degree of contrast enhancement of hypertrophic scar tissue was examined. All patients were scanned before and immediately after intravenous contrast application (volume: 1.5-2.0 ml/kg body weight, flow rate: 0.35 ml/sec). In 83% of the cases hypertrophic scar tissue did show definite contrast enhancement, whereas disc herniation remained unenhanced. Comparison between contrast enhancement and age of scar tissue produced poor correlation (r = 0.3012) with older scarring showing a trend towards lower enhancement levels. In cases where morphologic and topographic criteria in plain CT examination fail to yield a diagnosis, intravenous contrast application is recommended. Our data indicate that even those patients might benefit from the procedure who have been operated upon for disc herniation several months or years ago.

Adult↗
PubMed1984

[Focal liver diseases. Comparative study of computed tomography, conventional ultrasound and the automated multisector scanner (Octoson)].

A comparative study, on 251 patients, between CT, Octoson and conventional ultrasound, established that CT (with angio-CT) had the highest rate of sensitivity (95.86%). The Octoson examination had a higher sensitivity (92.58%) than the conventional ultrasonic examination (82.64%). This result is achieved because superficial and subdiaphragmatic metastases, which lie in the depth of the liver, are better presented by the Octoson than with a mechanical sector scanner. Superficial metastases need to be presented with a water-path transducer for superficial lesions and subdiaphragmatic metastases with a wide range focus transducer. These areas can also be accurately shown on scanners with a dynamic transducer. The specificity of these three methods lies between 90 and 96%.

Echinococcosis, Hepatic↗
PubMed1984

[Nuclear magnetic resonance tomography in space-occupying kidney lesions].

The kidneys in 15 patients (8 renal tumours, 4 cysts and 7 normal patients) were examined by means of super-conductive NMR tomography in order to assess the value of the method and its use in tumour staging. The findings were compared with computed tomography, angiography and surgery. Parenchymal tumours and cysts are easily recognised and differentiated, as they are on CT. NMR demonstrates a pseudo-capsule, which can otherwise only be seen on the angiogram, or on angio-CT. The extent in the peri- and pararenal space, infiltration into neighbouring organs and lymph nodes are equally well seen on NMR and CT. NMR equals angiography for demonstrating invasion into the renal vein and vena cava and, in this respect, is better than CT.

Adult↗
PubMed1984

[Computed tomographic staging of hypernephroid carcinoma].

In 68 patients with renal cell carcinoma computed tomographic staging was compared to the histopathologic staging. The classification based to the staging scheme developed by Robson. The CT criticized the tumor stages correctly in 82%. Consequently CT is superior to angiography, especially in detecting infiltration of the peri- and pararenal space and of lymph node metastases. Difficulties were found in detecting tumor extension into the renal vein near by the renal hilus.

Adult↗
PubMed1984

[Nuclear spin tomographic diagnosis of brain tumors using the contrast medium gadolinium-DTPA].

This study examines the effect of the NMR contrast medium gadolinium-DTPA on image contrast in cerebral tumours. Sixteen patients with space-occupying cerebral lesions were examined on a 0.35 Tesla superconducting scanner, using a T1-weighted spinecho sequence prior to and after the intravenous application of gadolinium-DTPA. In 8 patients T2-weighted spinecho-sequences were obtained before the administration of contrast. The tomograms were evaluated visually and according to quantitative criteria. The use of gadolinium-DTPA helps to evaluate the blood-brain barrier and improves diagnosis by differentiating tumour tissue from edema and from normal brain tissue.

Adult↗
PubMed1984

Pharmacokinetics of ethynyl estradiolsulfonate in minipigs.

The pharmacokinetics of ethynyl estradiolsulfonate labelled with 3H in the steroid nucleus and with 14C in the isopropylsulfonic acid side chain was investigated in male minipigs. The plasma level after intravenous administration was interpreted according to a three-compartment model. After oral administration the first two phases were overlapped by the absorption period. The renal and fecal excretion of the two labellings were investigated. In urine the majority of the 3H-labelled steroid was excreted in the unconjugated and in the glucuronide fractions. More than 70% of 14C in urine was unextractable.

Administration, Oral↗
PubMed1984

[Suspected herniated disk--differential diagnostic case studies by lumbar CT].

The most common reason a patient is referred for spinal CT examination is to exclude a ruptured intervertebral disc. Besides nerve root entrapment due to herniated disc, a number of unusual or unexpected conditions have been encountered in the course of CT lumbar spine studies. These include spondylolisthesis, spinal dysraphism, Paget's disease, and inflammatory, neoplastic, or metastatic lesions. The application of spinal (small-circle) target imaging includes the risk to overlook soft tissue lesions that extend beyond the reconstruction circle. Therefore, complete (large-circle) circumferential abdominal scanning is recommended in case of a suspected extraspinal cause of sciatica.

Adolescent↗
PubMed1984

[Arterial digital subtraction angiography for visualizing hemodialysis shunts].

Intraarterial application of contrast medium in digital video subtraction angiography was used to visualize chronic haemodialysis arteriovenous shunts. Patient compliance could be enhanced by the use of small volumes of non ionic contrast medium (3 ml/inj.), and the use off thin needles. The diagnostic reliability was excellent for all 25 examinations.

Adult↗
PubMed1983

Studies on pharmacokinetics of STS 557 in animal species and man.

Following oral and i.v. administration of [14 alpha, 15 alpha-3H]-STS 557 to beagle dogs, baboons, rats and female volunteers, plasma level courses of total radioactivity and STS 557, and radioactivity excretion in urine and feces have been investigated. Bioavailability of orally administered STS 557 was found to be 80--90% in man and beagle dog, 70--80% in baboon and rat. Concerning the systemic availability following oral administration of equivalent doses, the following order was established: beagle dog greater than man greater than baboon greater than rat. Equilibrium dialysis indicates species differences in plasma protein binding and a considerable part of STS 557 to be present in plasma unbound. STS 557 is rather rapidly eliminated from the plasma compartment of all species investigated with half lives less than or equal to 10 h. As an additional time parameter of pharmacokinetics the "mean residence time" was used. Urinary excretion of STS 557 metabolites is dominant in all species, including the rat. In contrast to the great part of STS 557 in plasma total radioactivity, only small amounts of unchanged STS 557 are excreted in urine. First results of current studies in rabbits are presented, too.

Animals↗
PubMed1983

[Possibility of error and difficulties in the computerized tomographic diagnosis of lumbar intervertebral disk prolapse].

In 310 computed axial tomograms of the lumbar spine which were studied retrospectively a number of pitfall situations were encountered. These in part were related to technical limitations, in part to degenerative joint disease and to postoperative hypertrophic scar formation. It became evident that the position of the disc within the intervertebral space may vary to a certain degree, a phenomenon not to be mistaken for disc protrusion.

Adolescent↗
PubMed1983

[Computer tomographic and echocardiographic diagnosis of intracardial space occupying masses].

Nineteen patients suspected of having intracavitary masses were examined by echo-cardiography and computer tomography. One 1 cm. thrombus on the mitral valve could be demonstrated only on the echo-cardiogram and was interpreted as a tumour. Both CT and echo-cardiograms produced occasional false negative findings with cardiac thrombi, which were ultimately diagnosed by the other method or by ventriculography. Differentiation between a thrombus and a tumour depends essentially on its localisation and on the history, and some morphological criteria. Echo-cardiography and densitometric measurements did not assist in the differential diagnosis. CT may be able to differentiate thrombus from tumour if the latter contained fat or has become cystic.

Adult↗
PubMed1983

[Thoracoscopic and computer tomographic findings in pleural mesotheliomas].

The computer tomographic findings in fifteen patients with histologically confirmed malignant pleural mesotheliomas were analysed. The results were compared with the findings on thoracoscopy and on conventional radiography. On CT, the tumour was not obscured by pleural effusion and the differential diagnosis of masses in the chest wall becomes narrower. Signs of asbestos exposure can be recognised at an early stage. Once the diagnosis has been confirmed histologically, CT demonstrates the tumour clearly. Involvement of the pericardium and mediastinum can be diagnosed with considerable certainty and involvement of the pleura may be assumed if there is an effusion. CT is an advance in the diagnosis of these rare tumours; it aids in arriving at a prognosis and in formulating treatment.

Adult↗
PubMed1983

[Computer tomographic diagnosis of spinal injuries].

The examination of patients with spinal trauma by computed tomography offers a direct view into the spinal canal. A stenosis of the spinal canal by fragments of a fracture or haematoma is recognized easily; myelography has become redundant. For the injured patient computed tomography is connected with only a minimal risk.

Fractures, Bone↗
PubMed1983

[Value of hypotonic duodenography in pancreatic diagnosis. Comparison with computer-tomographic findings].

61 patients with suggested pancreatic disease were examined by Hypotonic Duodenography (HD) and Computed Tomography (CT). After all examinations had been carried out, 45 patients were found to have an abnormal pancreas, and 16 patients had a normal pancreas. HD had a sensitivity of 60%, and a specificity of 94%, whereas CT had a sensitivity of 78% and a specificity of 100%. - HD is more sensitive than CT in detecting lesions originating from pancreatico-duodenal structures. In patients with uncertain clinical symptoms of the upper gastrointestinal tract HD is still a valuable basic examination. Only in patients with strongly suspected pancreatic carcinoma radiologic examination should start with CT because CT is more sensitive in detecting a pancreatic lesion and is helpful in assessing its extension and defining its etiology.

Adenocarcinoma↗
PubMed1983

[Animal experimental studies on the application of dynamic computed tomography to liver tumors].

Experiments on rabbits with implanted liver tumours have shown that iso-dense tumours, which are not visible on CT, may be demonstrated by dynamic CT following intravenous contrast injection. They may appear as hypodense areas during a period of maximal organ perfusion, if the tumours have not taken up the contrast. The ability to recognise tumours depends largely on intravascular and, only to a smaller extent, on interstitial contrast enhancement.

Animals↗
PubMed1983

[Value of intravenous digital subtraction angiography (DSA) for the assessment of surgical blood vessel reconstruction].

Intravenous digital subtraction angiography (DSA) was obtained in 55 cases after reconstructive procedures of the carotid arteries, the pelvic and lower limb arteries. In 48 cases (87%) the studies were of technically satisfactory or good quality. On DSA 32 vascular reconstructions were normal and 16 had typical complications like occlusions, stenoses, aneurysms and insufficient run-off. -Experience indicates that the spatial resolution of DSA is adequate for clinical purposes such as determining graft patency or the presence of postoperative complications. Because DSA is less invasive than catheter angiography, postoperative evaluation of patients having undergone peripheral surgical revascularization should start with DSA.

Aged↗