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Biomedical subjects

G Friedmann

Publications and source records attributed to G Friedmann.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Importance of rapid MR imaging for tumor diagnosis in the area of the kidneys and adrenals].

Gradient-echo pulse sequences with fast acquisition times permit examinations in short breath-holding intervals. In this way an improvement of MR imaging of upper abdominal organs can be expected. In 41 patients with space-occupying lesions of kidneys and adrenals, influence of external parameter variations on resulting contrasts was analyzed and results were compared to other imaging methods. Gradient-echo sequences demonstrated a high sensitivity in detection of tumorous lesions of kidneys and adrenals, the specificity being similar to that of CT. Further differentiation was only possible by performing dynamic perfusion studies using paramagnetic contrast agents.

Adrenal Gland Neoplasms↗
PubMed1988

Recurrent rectal cancer: diagnosis with MR imaging versus CT.

During an 18-month period, a prospective study comparing the findings at computed tomography (CT) and magnetic resonance (MR) imaging was conducted on 35 patients who satisfied the following criteria: prior surgery for rectal cancer (11 curative resections, 24 rectal amputations), perineal pain and/or elevated carcinoembryonic antigen (CEA) level, and a soft-tissue mass in the presacral fossa demonstrated at CT. Twenty-two patients had tumor recurrence; 13 patients had only inflammatory changes or radiation fibrosis. At a single examination of each patient (with no reference to prior baseline studies), MR imaging was more accurate than CT, largely because MR imaging was more successful in the distinction of recurrence from fibrosis based on the differences in signal intensity on T2-weighted images.

Adult↗
PubMed1988

[Computerized tomography in bronchial cancers].

For the exact evaluation of central and peripheral bronchogenic carcinoma CT is a usefull method that can provide important information needed by the clinicians. CT is able to demonstrate the exact extent of the disease and thus enable the surgeon to plan surgical intervention, to assess the risk involved or to decide for inoperability.

Carcinoma, Bronchogenic↗
PubMed1987

[Value of magnetic resonance tomography prior to surgery and irradiation of peripheral soft tissue tumors].

The experience with magnetic resonance imaging (MRI) of 37 patients with peripheral soft tissue tumours and tumour-like lesions is reported. MRI proved to be a highly sensitive method in detecting soft tissue tumours. The main advantages of MRI compared to CT were the high contrast resolution of MRI and the multiplanar display. The anatomic setting of the soft parts tumour could be defined in most cases as either intracompartmental or extracompartmental. The relationship to the major neurovascular bundles and bone could be assessed accurately. Tumour-induced subtle periosteal reactions and cortical erosions are better defined with CT and plain film, especially. An imaging technique using small excitation angles, echoes produced by gradient inversion and extremely fast repetition times ("Fast Field Echo Imaging") is capable of producing MR images in only a few seconds acquisition time. Preliminary experience shows that soft tissue tumours can be evaluated with this rapid pulse sequence.

Chondroma↗
PubMed1987

[DSA for the imaging of tumor-caused vascular changes and complications during local chemotherapy of the liver via the portal system].

In 18 patients with primary or secondary liver tumours, 38 digital subtraction angiographies (DSA) of totally implanted catheter systems for liver perfusion were performed during a period of 8 months. The systems had been used for an average of 6.9 months. In 22 out of 38 examinations secondary reactions of liver arteries were observed, in 7 the therapeutic regimen was changed after DSA. Patients with an extensive tumour involvement of the liver showed mural thromboses or obstructions of liver arteries relatively more often (4 of 7) than patients with smaller size tumours (2 of 11). In 7 cases the therapeutic regimen was changed after DSA. DSA of implanted liver catheters is a valuable, well tolerated, easily and rapidly performed method.

Adult↗
PubMed1987

[Experimental research and initial clinical experience with the fast field-echo sequence].

In the FFE-sequence the new parameter "flip angle" introduces, besides the possibility of fast MR-imaging, an increased variability of external MR parameters. Experimental studies in healthy volunteers and patient examinations were carried out to establish the most useful parameter combinations giving reasonable contrasts. Variation of external parameters allows a manipulation of image contrasts: using small flip angles in combination with longer TE good T2-weighted images can be achieved; large flip angles with short TR and TE produce a sufficient T1-weighting. In this way the FFE sequence proves to be a valuable method for rapid assessment of pathologic lesions.

Evaluation Studies as Topic↗
PubMed1987

[Magnetic resonance tomography in acoustic neurinomas].

The possibilities of MR and CT were compared in respect of neurinomas of the acoustic nerve (n. acusticus). The comparison showed that MR detection of tumours in the posterior of the cranial cavity is the more sensitive method, especially in respect of neurinomas of the acoustic nerve, although CT enables the use of the small-level technique with or without the addition of a contrast substance, as well as the application of pneumocisternography. The sensitivity of MR can be increased further by adding a contrast medium. Whereas in diagnosis of extrameatal neurinomas of the n. acusticus, CT and MR are of equal value, MR shows substantial advantages over CT in the diagnosis of intrameatal tumours (without enlargement of the inner ear canal). The same holds true for very small tumours of up to 1 mm diameter, the visualisation of which is greatly facilitated by the multidimensional possibilities of MR and by the administration of a contrast medium.

Cerebellopontine Angle↗
PubMed1987

[Initial experiences with gadolinium DTPA in magnetic resonance tomography of bone and soft tissue tumors].

MR was performed in 41 patients suffering from benign and malignant bone and soft-tissue tumor before and after intravenous injection of the paramagnetic agent gadolinium-DTPA (Gd-DTPA). Using T1-weighted parameters, the contrast of tumor tissue versus muscle could be increased by Gd-DTPA. Thus, extraosseous extension as well as infiltration of the spinal canal was depicted to better advantage. Inhomogeneities were visualized with higher frequency and improved contrast. In several instances, there was no differentiation between tumor and adjacent edema without application of Gd-DTPA. T2-weighted images without Gd-DTPA exhibited higher contrast as compared to T1-weighted images after Gd-DTPA. The contrast to tumor tissue versus fat and bone marrow respectively was reduced after applying Gd-DTPA. Thus, for the evaluation of bone marrow infiltration, T1-weighted images without Gd-DTPA proved to be indispensable.

Adolescent↗
PubMed1986

Radiology of pulmonary metastases: comparison of imaging techniques with operative findings.

The operative findings at 27 thoracotomies in 24 patients were compared with the results of chest X-rays, computerized tomographies and conventional tomographies. Radiological and operative findings corresponded in 15 of 27 cases. The computerized tomography proved to be the most sensitive method for the estimation of the number of metastases. The foci often located close to the pleura repeatedly cause an exudative reaction of the visceral pleura and thus mark the interlobular septa. These changes were most distinctly recognized by conventional tomography and gave indications for the topographic classification of the metastases. Despite the careful evaluation of the imaging techniques small metastases were often not detected.

Adolescent↗
PubMed1986

[Preoperative staging of bronchial carcinoma. Value of magnetic resonance in comparison with computed tomography].

The results of MR and CT examinations for tumour staging were compared in 30 patients with bronchial carcinomas. They were also related to operability. The findings have been compared with the data in the previous literature. The results have shown both methods to be of equal value. The differentiation between tumour tissue and vascular structures is somewhat better shown by magnetic resonance, but peripheral and bone involvement is better shown on CT. These results require further examinations as well as operative and histological confirmation.

Adult↗
PubMed1986

[Magnetic resonance tomography of brain tumors--comparison of the results using the multi-echo technic and gadolinium-DTPA].

In thirty-seven MR examinations of intracranial tumours equivalent sections were obtained in a multi-echo technique before and after intravenous injection of 0.1 mmol. gadolinium DTPA/kg body weight. From this comparison the following preliminary conclusions have been drawn concerning the demonstration of the tumour, its delineation and type: Contrast administration does not unequivocally improve the sensitivity. In 55% of the cases, differentiation between tumour and oedema respectively normal brain tissue was easier after Gd-DTPA. Diffusely infiltrating gliomas remain a problem, since their extent is uncertain with or without contrast medium. The structure of the tumour can already be adequately characterized by the multi-echo technique. In order to diagnose the type of tumour, the criteria which apply to Gd-DTPA are similar to those used for iodine-containing contrast media in CT.

Astrocytoma↗
PubMed1986

[MR of ischemic brain diseases. A comparison with CT, PET (18-fluorodeoxyglucose) and angiographic results].

The results of MRI and CT in 55 patients with brain infarcts were compared; in 26 of these cases an additional PET examination was obtained in order to study the regional glucose utilisation. MRI was superior to CT, demonstrating 11% more of the infarcts, particularly during the first 24 hours, in small lesions confined to the grey or subcortical white matter and in infratentorial ischemic lesion. On the other hand, only CT was able to show fresh hemorrhage, although MRI was the method of choice to demonstrate old blood collections. To characterise the follow up of an infarct, CT and MRI were similar, except the marginal contrast enhancement sometimes demonstrated by CT studies between the 2nd and 4th week after stroke event. PET was inferior to show details because of its poorer spatial resolution, but anyhow had a high sensitivity and provided additional informations concerning secondary inactivations of brain areas not directly damaged. Additionally PET was able to demonstrate areas of anaerobic glycolysis and lesions of diminished glucose utilisation in TIAs. Small areas of gliosis in the white matter of the cerebral hemispheres were frequently found in patients with cerebro-vascular diseases; they were best shown by MRI, but do not correlate with the extent of vascular stenoses or occlusions, shown by angiography.

Adolescent↗
PubMed1986

[Magnetic resonance tomography of spinal masses].

We examined 22 intramedullary, 17 intradural extramedullary and 20 extradural lesions, with direct involvement of the spinal cord by magnetic resonance tomography, using surface coils and 5 mm., or narrower continuous sections. Spinecho pulse sequences are suitable for multi-slice examinations. T.1-weighted examinations are suitable for demonstrating the syrinx in syringomyelia, in all other circumstances T1 and T2 sequences are essential. Gd-DTPA is unnecessary. The results of these recommendations are illustrated.

Astrocytoma↗
PubMed1986

[Magnetic resonance tomographic findings in esophageal cancer].

The value of MRT and CT for staging and for determining operability of carcinoma of the oesophagus was assessed in 20 patients with histologically confirmed diagnoses. Both methods are limited in this respect. In some cases magnetic resonance provides more accurate concerning the extent of the tumour; this, however, is true only for lesions in the upper and middle thirds of the oesophagus. Where tumours of the distal third of the oesophagus are concerned, and particularly in those extending into the fundus of the stomach, CT is clearly superior. Both methods are of limited value in assessing the depth of tumour penetration, infiltration of neighbouring organs and involvement of regional lymph nodes.

Aged↗
PubMed1986

Image quality in intravenous renal DSA. A critical analysis of 300 examinations.

Renal venous DSA yields diagnostically adequate results in an unselected population in more than 85% of cases. Image quality is compromised predominantly by inadequate contrast enhancement, motion artifacts from the stomach and the bowel, and obesity. The effect of these factors increases with patient age. Selection of patients, careful bowel preparation, the use of a compression device and intravenous spasmolytics are recommended to improve image quality. The possible contributions of the injection technique, pulsed DSA and advanced post-processing facilities are discussed.

Adolescent↗