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Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 559 records · Page 31Linked to original sources
PubMed1992

[Typical findings and erroneous findings in SPECT-radioimmunoscintigraphy using 99mTc-labeled CEA antibodies in colorectal tumors].

Radioimmunoscintigraphy with 99mTc-labelled monoclonal antibodies against Carcino-Embryonic-Antigen (CEA) is increasingly accepted in the follow-up of patients suffering from colorectal carcinomas. However, interpretation of transversal, coronal and sagittal reconstructions of "Single Photon Emission Computed Tomography" radioimmunoscintigraphic studies is difficult due to physiological antibody accumulations and anatomical based variations of antibody distribution. In the following study we demonstrate therefore, the typical findings and "pitfalls" of radioimmunoscintigraphy with 99mTc-labelled CEA antibodies in comparison to findings in computed tomography, to help to avoid misinterpretations.

Adult↗
PubMed1992

[Interstitial lung changes in high-resolution computed tomography].

With high-resolution computed tomography (HR-CT) it is possible to localize interstitial pulmonary disease of different etiology within the secondary pulmonary lobule. This may be most successful in the periphery of these interstitial lesions where lobular architecture is best preserved. In the areas of maximal changes, pathological findings are sometimes so severe that the base structures of the lobule cannot be identified. Since abnormalities in the peripheral zone of a pathologic progress normally represent early changes, analysis of the distribution pattern may allow to describe the mode of extension and to narrow down the differential diagnosis. Detection of the pattern of abnormal densities within in the secondary pulmonary lobule enables only a morphological description. Pathognomic distributions are at present not defined radiologically. Moreover, a wide spectrum of CT findings, occasionally overlapping, may occur in interstitial diseases. Nevertheless, the described additional observations are helpful in diagnosis and allow to avoid invasive methods in selected cases. However, HR-CT is certainly useful in defining the optimal localisation of tissue sampling either by bronchoscopy or open lung biopsy. Evaluation of disease activity seems to be possible, too. Further radiological pathological correlations in larger prospective studies are necessary to define the diagnostic value of this new technique.

Asbestosis↗
PubMed1992

[The place of radioimmunoscintigraphy in the diagnosis and follow-up of ovarian cancer in comparison with computed tomography and second-look surgery].

In this prospective study the diagnostic capability of radioimmunoscintigraphy (RIS) was compared with that of computed tomography (CT) and of "second look" surgery as primary diagnostic procedures in 27 patients and in the follow-up of 52 women suspected of suffering from ovarian cancer. The results were compared with immunohistochemical findings and CA125 serum levels. For primary diagnosis sensitivity, specificity and diagnostic accuracy of RIS was 100%, 60% and 90%, resp. In follow-up, sensitivity for local recurrencies was 75% and specificity 68%. Peritoneal carcinosis in the pelvis and lower abdominal region was better detectable by RIS, but for detection of liver metastases CT showed better results. CT and RIS could not replace "second look" surgery.

Adult↗
PubMed1992

[The splenic steal syndrome and the gastroduodenal steal syndrome in patients before and after liver transplantation].

The study describes new pathologic entities, the splenohepatic steal-syndrome and the gastroduodenal steal-syndrome, which could be demonstrated by angiography in 17 patients before and after liver transplantation. After the first observation of a splenohepatic steal-syndrome in a patient with unexplained elevation of hepatic enzymes after liver transplantation, a prospective angiographic study was performed, including all liver transplant recipients and patients after liver transplantation with unexplained impaired liver function tests. 9 splenohepatic steal-syndromes could be demonstrated before and 7 after hepatic transplantation, one gastroduodenal steal was seen after liver transplantation. The different therapeutic modalities are discussed.

Angiography↗
PubMed1992

[Anterior cruciate ligament rupture: MT versus arthroscopy].

Because of suspected rupture of the anterior cruciate ligament sixteen acute traumatised patients were investigated by MR and arthroscopy. The MR diagnosis of a lesion of the anterior cruciate ligament proved to be correct by arthroscopy in fifteen of sixteen cases. Diagnostic criteria for lesions of the anterior cruciate ligament were: Increased signal intensity in T1- and T2 weighted images, increased volume and discontinuity of ligamentous structures. Additional MR findings of meniscal tears were correct in three of four cases laterally and in four of four cases medially. Femoral cartilage lesion were correctly identified by MR in three cases. MR normal findings proved to be correct by arthroscopy in another five cases.

Adolescent↗
PubMed1991

[Magnetic resonance tomographic and sonographic imaging of the ankle in marathon runners].

Calcaneus tendons and ankles of 25 practising marathon runners were investigated by sonography and MR. We applied a 7.5 MHz transducer for sonography. Axial and sagittal T1-weighted, proton density-weighted, and T2-weighted SE images were performed. MR proved superior to sonography. Degenerative alterations of the calcaneus tendon, tendovaginitis of the flexor hallucis longus muscle, joint effusions and cartilage disease were diagnosed by MR but remained undetected by sonography.

Adult↗
PubMed1991

[Gadolinium-DTPA as an oral contrast medium for magnetic resonance tomography of the pancreas].

52 patients with normal pancreas, pancreatitis and pancreatic tumors were examined by magnetic resonance imaging (Magnetom 0.5 T). Using T1-, proton density- and T2-weighted spin-echo sequences images were obtained before and after oral administration of Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l Mannit, 5-13 ml/kg). Gd-DTPA resulted in hyperintense labeling of small bowel in all sequences and improved visualization of pancreatic head, body and tail in 15, 14 and 7 of 27 patients with normal pancreas and in 17, 8 and 6 of 25 patients with diseased pancreas. Better delineation of pseudocysts and tumorous gut wall invasion were diagnostically profitable. With regard to motion artifact reduced MRI of the intestine using fast sequences Gd-DTPA may be a suitable oral contrast agent to improve the imaging of the pancreas.

Administration, Oral↗
PubMed1991

[The demonstration of calcifications in magnetic resonance tomography (MRT). The effect of different parameters on the MRT imaging of cerebral calcifications].

The effect of various factors on the demonstration of calcified lesions was studied in 131 areas of calcification which had been demonstrated by CT. By means of MRI (SE 400/30 or GE315/14, 90 degrees and SE 1600/30 + 70; 0.5T) 117 of the 131 calcified lesions (89%) produced a signal difference. Of these 117 lesions, 80 (61%) were recognised as calcification by MRI. Large areas of calcification (more than 5 mm) and high density calcification (more than 100 Hu) were recognised significantly more often than small or low density calcifications. T2-weighted images demonstrated calcification more often than other sequences. With conventional pulse sequences, calcified lesions were frequently recognised as abnormalities on MRI, but their recognition as calcified lesions is unreliable.

Brain↗
PubMed1991

[Superselective intra-arterial DSA in femur head necrosis and femoral neck fractures].

The prospective study includes 25 patients without pathology of the femoral head for the evaluation of the normal femoral head perfusion. In addition 34 patients with femoral head necrosis underwent i.a. DSA preoperatively before pedicled pelvic bone grafting. 15 patients after pelvic bone graft operation and 7 patients with medial femoral head fracture were also examined via superselective DSA. In cases with femoral head necrosis a rarefaction or interruption of the rami nutricii proximales, or an occlusion of the medial circumflex femoral artery were observed. Patients with medial femoral neck fracture showed an interruption of the rami nutricii proximales of the femoral head. Postoperative DSA--after pedicled pelvic bone graft--revealed a regular arterial graft perfusion in 82%.

Adult↗
PubMed1991

[Magnetic resonance tomographic screening studies of the bone marrow with gradient echo sequences: (I) the contrast relations of phase-identical and phase-shifted gradient echo sequences. Studies on probands and pathological-anatomical preparations].

Anatomical specimens and normal persons were studied by gradient echo MR imaging to determine the influence of different echo times (TE) on bone marrow contrast. First of all, six normal persons were studied to determine specific echo times for in-phase and opposed-phase states. Using different sequences bone marrow contrast in isolated femoral bones was determined and compared to results of pathological exams. Red bone marrow had no signal on opposed-phase images; contrast between red and yellow marrow was higher on opposed-phase than on in-phase images. Bone marrow lesions can be expected to be visualised with high signal on opposed-phase images; this technique should be especially suited for MR imaging of bone marrow.

Adult↗
PubMed1991

[The differential diagnosis of liver metastasis and regional fatty liver: a comparison of CT and MRT].

Differentiation between liver metastases and local fat deposition may be difficult when using CT; the value of MRI was therefore investigated in 18 patients with metastases and ten patients with fat deposits. CT shows both lesions as similar hypodense areas. MRI, however, produces different appearances: T1- and 2-weighted images show marked differences in the signal arising from metastases, whereas local fat collections in both sequences differ little in their signal from normal liver. Quantitative MRI signal intensity of the two types of lesion were also different. Where the differentiation by CT may be difficult, it may be made with certainty by means of MRI.

Adult↗
PubMed1991

[Transcranial Doppler sonography in cerebrovascular diseases].

A review of our 1 1/2 years' experience with transcranial Doppler sonography (TCD) is given. In total, 619 TCD examinations were performed. Considering physiological variations of blood flow velocities in the intracranial arteries, TCD findings in stenoses and occlusions of the extracranial and intracranial brain-supplying arteries as well as in intracranial vasospasms were evaluated. In patients with leptomeningeal anastomoses demonstrated by TCD in the region of the peripheral middle cerebral artery, the regional cerebral blood flow was measured by 99mTc-HMPAO-SPECT. The value and limitations of TCD in cerebrovascular diseases and the indications to TCD examination of the intracranial arteries are discussed.

Carotid Artery Diseases↗