Search PubMed⌕ Search

Biomedical subjects

P Lukas

Publications and source records attributed to P Lukas.

65 records · Page 4Linked to original sources
PubMed1985

The effects of fluid-mechanical factors on MR imaging in the arterial model.

Blood flow is a significant factor in MR imaging. The purpose of this investigation was to study fluid-mechanical effects on MR imaging. MR images generated by the pulsatile flow of bovine blood in an elastic model of the aorta with both renal arteries were studied. The high-frequency pulse sequence was synchronized to an ECG trigger signal. It was demonstrated that different flow velocities, laminar and turbulent flow, and backward flow can be visualized with MR imaging.

Aorta↗
PubMed1985

[Computed tomographic findings in amebiasis].

With an increase of travel to foreign countries with endemic amoebiasis we will find this disease also in western countries. The typical pathologic changes can be identified in CT, as we report in a case with proved amoebiasis which showed an abscess in the bowel-wall and another in the neighbouring liver.

Adult↗
PubMed1984

[False interpretations of computed tomograms in malignant lymph node diseases of the pelvis and abdomen].

In the presence of a retroperitoneal mass with loss of normal aortic and caval contours no distinction can be made by CT between metastases or malignant lymphoma and primary sarcoma or retroperitoneal fibrosis if a primary tumour is not known. A false diagnose is quite possible if intestinal loops or vessels are considered as enlarged lymph nodes. These pitfalls can be avoided by intravenous application of contrast medium and by filling of all intestinal loops with orally administered contrast medium, in special cases even via a gastric tube. Pitfalls in post-therapeutic changes, like haematoma, scar tissue or lymphocele, are confounded with tumour recurrence of recent metastases and are give false-positive results in follow-up examinations. If no regression of lymph node enlargement after therapy is observed, a distinction between active metastases and nodal induration is impossible. False-negative results are due to metastatic, but not enlarged lymph nodes and cannot be avoided by CT.

Abdominal Neoplasms↗
PubMed1984

MR-tomography in the diagnosis of malignant soft-tissue tumours.

Nine patients with malignant, peripheral soft-tissue tumours were examined using a 0.35 T MR equipment. In 7 cases in which tumour presence was surgically verified, a definite identification as well as an exact determination of tumour extension was achieved using MR. The various tumours exhibited a particularly high degree of contrast when using a T2-weighted Spin-Echo-(SE) as well as the T1-weighted Inversion-Recovery-(IR) mode. The T1- and T2-relaxation times of the soft-tissue malignancies evaluated in this study were markedly longer than those obtained for normal tissue. In 2 patients within the collective, a definite exclusion of tumour recurrence was possible.

Adolescent↗
PubMed1981

[Sonographic determination of thyroid volume. Comparison with other methods (author's transl)].

Using ultrasound it is possible to determine the thyroid volume with a maximal error of 12%. The method is based on the electronic planimetry of a sequence of transverse ultrasound scans of the thyroid. Following this, the "slices" are added using a small computer. On 101 patients five commonly used methods of volume determination were compared with this reference technique. The volume estimation by palpation and interpretation of the scintigram as well as the volume calculation from the scintigram area or from an ellipsoid model gave maximal errors between plus or minus 82% and plus or minus 90%. The combination of scintigram area or scintigraphically determined length and width of a single thyroid lobe and the sonographically measured thickness reduced the maximal error to plus or minus 35% and plus or minus 37%. In 10 patients teh reproducibility of the reference technique was excellent and the absolute maximal error was 4.6%, even when the patients were differently positioned.

Adolescent↗
PubMedDate not supplied

[Imaging of the internal structures of the knee by MR tomography].

With magnetic resonance imaging it is possible to demonstrate the cruciate ligaments of the knee reproducibly without the need for invasive measures. Prerequisites for this are high-resolution coil systems and a stratum thickness of 5 mm or less. Examination of 29 patients and volunteers showed that normal cruciate ligaments can be delineated as homogeneous zones of low signal intensity and high contrast from the surrounding fatty tissue, while in cases of injury to the cruciate ligaments an interruption of the ligament structure, inability to detect them in anatomic position, or an intermediate signal is observed. In 13 cases operated on, with 12 injuries of the cruciate ligaments, the MR findings corresponded to findings at surgery. In 6 patients who had previously had cruciate ligament plasties there correlation with clinical findings was only partial.

Adolescent↗
PubMedDate not supplied

[Clinical value of MR tomography of spondylodiscitis in ankylosing spondylitis].

The extent of bone marrow edema seems relevant in assessing the activity of discovertebral destructions in ankylosing spondylitis using highly T2-weighted images. Twenty-one patients showing 32 discovertebral lesions in total were examined by MR-imaging. Radiological progression of destruction is significantly connected with the extent of bone marrow edema. Areas of probable progression can be visualized, which is especially valuable in polysegmental distribution. MR-imaging of discovertebral lesions facilitates the planning of therapy, particularly concerning surgical stabilization.

Adult↗