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Biomedical subjects

P Lukas

Publications and source records attributed to P Lukas.

At least 55 records · Page 3Linked to original sources
PubMed1990

[The weighting of SE, IE and GE sequences in tumors of the head and neck].

In a review of 82 patients having different benign and malignant head and neck tumours we studied the value of spin echo (SE), inversion echo (IE) and gradient echo (GE) sequences. The strong T1 weighted IE mode is highly sensitive to demonstrate pathological tissue. Tumour diagnosis was in 20% and lymph node diagnosis in 29% better than T2 weighted SE sequences. According to this experience we choose the IE mode as the first one for all patients examined for tumour staging. All other sequences and orientations are planned on this tomograms knowing the location of the tumour and lymph nodes. T1 weighted SE mode is indispensable and should be recorded in transversal orientation, covering the whole head and neck region. This mode has the best imaging of anatomical structures as the known fatty limitations. The best differentiation of the tumour is usually obtained after contrast enhancement by i.v. Gd-DTPA. The highest contrast enhancement is seen on T1 weighted GE tomograms, which we prefer. T2 weighted SE sequences are less sensitive than IE sequences and T1 weighted tomograms after Gd-DTPA to show the tumour. The T2 weighted SE mode cannot be replaced by the T2 weighted GE mode having a better signal to noise ratio. To minimise the scan-time of T2 weighted SE mode, only one measurement is performed; the quality of the tomograms is satisfactory.

Adult↗
PubMed1990

[NMR tomography compared to skeletal scintigraphy after traumatic vertebral body fractures].

MRI and scintigraphy were compared in 73 patients with 104 vertebral fractures aged between three days and 64 months. MRI was performed at 0.5 Tesla and 1.5 Tesla using T1- and T2-weighted spin-echo sequences. Isotope uptake was divided into four grades (normal, mild, moderate and marked increase). 92% of cases aged 0-6 months showed increased signal intensity on T2 sequences. This finding reflects edema in the bone. All these cases showed moderate or markedly increased uptake in 86%. The increased signal intensity in T2 spin-echo images provides a criterion for differentiating new from old fractures. The identification of normal fatty marrow in 91% of fractured vertebrae provides an important means for distinguishing traumatic from neoplastic fractures. One can also demonstrate bleeding, fatty change and sclerotic bone. MRI is less sensitive than scintigraphy, but more specific in following the posttraumatic healing process.

Adolescent↗
PubMed1987

Age-related morphology of the normal pancreas on computed tomography.

Abdominal computed tomographic scans were performed on a group of 360 patients between the ages of 20 and 80 years. The anteroposterior diameter of the pancreatic head, body, and tail, the age-related ratio of vertebral body-pancreas diameter, and the external and internal contours of the organ were analyzed. The age-related changes in the pancreas were compared with known anatomical findings.

Adult↗
PubMed1986

[Applicability of nuclear spin tomography to heart diseases].

Thirty-one patients with abnormalities of the heart and ten controls were examined by ECG-triggered nuclear resonance tomography. All patients had previously been completely investigated. Chamber sizes and mural thickness could be reliably demonstrated and, in addition, it was possible to show areas which could not be easily investigated by echocardiography. Visualisation of the valves was limited, but intra- and para-cardial lesions could be differentiated by a double echo technique. Absence and defects of septa could be shown exactly, as well as accurate demonstration of the relationship of the large vessels to the cardiac chambers.

Aortic Dissection↗
PubMed1986

[MR tomography of gynecologic diseases of the minor pelvis].

The results of MR examinations of 31 women with gynaecological diseases are described; all had CT and histological confirmation at operation. The extent and relationship of the lesions were well demonstrated by the three-dimensional sections of MR, in some cases better than on CT. Variations in the signals allowed better differentiation of myomas and ovarian carcinomas from normal tissue. Like CT, MR tomography was not reliable in showing the extent of infiltration into neighbouring structures.

Adult↗
PubMed1986

[Imaging of cruciate ligament injuries using MR tomography].

The cruciate ligaments of the knee joint can be demonstrated by magnetic resonance tomography, without using invasive methods. High resolution coils and section thickness of less than 5 mm are necessary. Sixty-six patients and volunteers were examined; the results show that the normal cruciate ligaments present as homogeneous zones of low signal intensity within the surrounding fat. Injuries to the cruciate ligaments interrupt the image of the ligaments, change their anatomical position or produce a signal of intermediate intensity. Eighteen operations were carried out on fifteen patients with cruciate ligament injuries and there was good agreement between the MR and the operative findings. Sixteen patients had had previous cruciate surgery and in these there was only partial correlation with the clinical findings.

Adolescent↗
PubMed1986

[Diagnosis of spondylitis by MR tomography].

The results of MR tomography in 13 patients with specific and nonspecific spondylitis are reported. There were characteristic changes in signal intensity and in the configuration of the vertebral bodies and the intervertebral discs. The extent of intraspinal stenosis can be demonstrated accurately by MR. Paravertebral abscesses can be shown accurately and their position can be clarified by means of multiplanar sections. The early diagnosis of spondylitis by MR tomography is discussed.

Adult↗
PubMed1985

[Diagnosis of bone necrosis by magnetic resonance tomography. The potentials for early diagnosis].

Twenty-eight patients with necrosis in the hip joint, the femoral condyles and the talus were examined by MR tomography. This revealed various features whose frequency depended upon the various stages of the necrosis. Three patients who showed no, or only indefinite, changes on radiographs, displayed clear evidence of necrosis on MR. Staging of femoral head necrosis on the basis of MR criteria is suggested, as well as a suitable procedure for early diagnosis. Accurate localisation and knowledge of the extent of the necrosis by means of MR makes it possible to plan an osteotomy accurately.

Adolescent↗
PubMed1985

MR in the diagnosis of bone tumours.

Forty-two patients with benign as well as malignant bone tumours or with tumour-like lesions of bone were evaluated using MR tomography. The appropriate choice of examination parameters is an essential prerequisite for the adequate visualisation and the definitive verification of the presence of a tumour. By means of its multi-planar display, MR provides definite advantages in the determination of tumour localisation and extension as well as in differentiating intra-tumoural haemorrhage from surrounding, non-involved tissue. In addition, the clear delineation of neighbouring structures such as muscular compartments and blood vessels achieved in MR can be useful in the planning of an eventual surgical approach. This new technique has proved itself superior to other available imaging modalities in the differentiation of residual or recurrent tumour from post-operative changes. A characterisation of the nature or histology of a suspicious lesion on the basis of relaxation-times or signal intensities, however, is not yet possible.

Adolescent↗