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Biomedical subjects

W Dewes

Publications and source records attributed to W Dewes.

At least 19 recordsLinked to original sources
PubMed1992

[The diagnosis of bone marrow lesions in the MR tomogram in children with diseases of the hematopoietic system with special reference to post-therapy changes].

119 MR-examinations of both tibiae, knees and the lower part of both femur were performed in 41 children suffering from bone marrow disease (27 ALL, 4 AML, 3 NHL, 1 agranulocytosis, 6 anaemia). T1- and T2-spin-echo sequences and a T2-gradient-echo sequence were used. Bone marrow changes in leukaemia were diffuse before therapy and patchy after therapy. Due to their different signal in T2-weighted images, differentiation of the post-therapeutic patchy findings into infiltrations, fibrosis, necrosis and siderosis seems to be possible. In future, MRI will be the method of choice for screening and controlling bone marrow disease if the examination time is shortened by using only a T1-spin-echo sequence and a T2-gradient-echo sequence.

Adolescent↗
PubMed1992

[The demonstration and staging of bladder carcinoma. A comparative study between magnetic resonance tomography, computed tomography and radioimmunoscintigraphy].

The purpose of the present study was to compare the effectiveness of MRI, CT and radioimmunoscintigraphy in the staging and detection of bladder cancers in 28 patients. We distinguish two groups: Group I included the tumour stages CIS-T3A and the second group the deep infiltrative tumours T3B-T4. MRI was slightly superior to CT in respect of tumour staging (75% correct results as compared to 63%). No understaging occurred with MRI, whereas in 22% of the cases the stage of the tumour was underestimated using CT diagnostics. Overstaging occurred in 25% of the MRI and 15% of the CT-diagnostics, respectively. RIS cannot distinguish the tumour groups, and hence this method is useful only for the detection of the primary tumour and metastases. In 77% of cases the tumour was detected and in 15% the tumour could be safely excluded.

Adult↗
PubMed1992

[MR tomography of the lower limbs of children with diseases of the hematopoietic system].

In 41 children with disorders of the hematopoetic system 119 MR examinations of both tibiae and knees were performed (T1 and T2 spin-echo sequences and a T2 gradient-echo sequence). Before therapy bone marrow changes in leukemia were diffuse, and patchy during and after therapy. Signals in T2-weighted images were different for infiltrations, fibrosis, necrosis and siderosis. In 3 children suspected of suffering from osteomyelitis, Ewing-sarcoma or coxitis, MR examination was the first to show the correct diagnosis. Therefore in children indications for MR tomography should be handled more generously to win time for therapy. Using only a T1 spin-echo sequence and a T2 gradient-echo sequence screening of more than one region is capable of controlling bone marrow diseases.

Acute Disease↗
PubMed1992

[Tuberous sclerosis: broadening of the diagnosis using MR tomography and computed tomography].

Ten children and a 22-y old women with tuberous sclerosis were studied. All children were epileptic but only 8 had skin lesions (white spots, sebaceous adenoma), 4 had rhabdomyoma of the heart and 4 children had astrocytoma of the retina; only in 4 children was the entire triad of tuberous sclerosis seen. The young woman with a hemorrhage of an angiolipoma of the kidney had no other symptoms of tuberous sclerosis. All patients had pathologic CT and MRT findings; 4 different types of lesion were seen in MRT. In order to elucidate human genetic aspects and to demonstrate the underlying disease all children with epileptic disorders and also all patients without the full triad of symptoms should be examined by MRT.

Adult↗
PubMed1992

[Radioimmunoscintigraphy and magnetic resonance tomography in the diagnosis of urinary bladder cancer].

Magnetic resonance tomography is a method which is sufficiently precise to demonstrate morphological changes for tumor staging of carcinoma of the urinary bladder. The stage of the tumor was correct in 68 resp. 86% of the patients. The RIS shows organ and lymph node metastases and has the capability to differentiating between scar and tumor after transurethral resection. The local spread, especially the infiltration depth of the tumor, is not visible. In 90% of the patients a primary tumor was detected, only in 5 cases a false-negative and in 2 cases a false-positive finding was made.

Adult↗
PubMed1992

[Clinical value of the ultrafast gradient echo sequence "Quickflash"].

It is possible to develop faster sequences with 6 mT/m gradient field strength. However, the short gradient switch times which are advantageous for a better image contrast cannot be achieved. Using longer measurement times the influence of the preparation pulses is less dominant. The image quality of the quickflash is poorer than that of conventional SE and GE sequences. In some cases, especially for outline views and in the evaluation of Gd inflow into pathologic tissue or in restless patients, we use the quickflash in clinical routine.

Brain Diseases↗
PubMed1991

Brain SPECT imaging with Tc-99m HMPAO in ophthalmoplegia plus.

In 14 patients with ophthalmoplegia plus Tc-99m hexamethylpropylene amineoxime (HMPAO) brain SPECT imaging was performed. Three patients showed bilateral parieto-occipital hypoperfusions, and two patients had left parietal defects (one with an additional right temporal lesion). Two patients presented with occipital hypoperfusions and one with a distinct hypoperfusion in the medial part of both frontal lobes. Hypoperfusion of the visual cortex might result from permanently decreased input from the degenerated retina. The hypoperfusion in the visual cortex and in other regions alternatively might reflect direct central nervous system (CNS) involvement due to neuronal degeneration or to impaired vascular function caused by morphologically changed mitochondria in smooth muscle and endothelial cells. The data suggest CNS involvement in ophthalmoplegia plus with abnormalities of cerebral blood flow similar to those found in other mitochondrial encephalomyopathies.

Adult↗
PubMed1991

[Cerebral MRT in x chromosome linked adrenoleukodystrophy].

Adrenoleukodystrophy (ALD) is a rare lipid storage disease, characterized among other symptoms by a progressive demyelinization of white matter. Changes are well demonstrated by MRT: Leukencephalopathy begins symmetrically in the occipital lobes of the cerebrum and involves furthermore the splenium of the corpus callosum, the nucleus dentatus and the descending tracts. As neurologic signs may precede signs of adrenal insufficiency, MRT may be important to suspect the diagnosis of ALD, which generally is diagnosed by biochemical tests.

Adrenoleukodystrophy↗
PubMed1991

[MRT and 99mTc-HM-PAO SPECT of the brain in myasthenia gravis].

Fourteen patients suffering from myasthenia gravis underwent cranial MRI and 99mTc-HM-PAO SPECT examinations. T2-WI revealed solitary white matter and/or basal ganglia lesions in four, multiple lesions in eight patients. The evaluation of the rCBF demonstrated a circumscript decrease of cortical perfusion in one patient whereas eight patients showed multiple cortical areas of hypoperfusion. In the context of an increased incidence of intrathecal immune reaction as well as of a constantly impaired cognitive performance of these patients, imaging findings might be a correlate of a primary cerebral manifestation of myasthenia.

Adult↗
PubMed1991

[Cerebral manifestations of Erdheim-Chester disease].

Cerebral manifestations of Erdheim-Chester disease are variable, giving a picture like that of multiple sclerosis. White matter lesions are located mainly in cerebellum and pons and lipid granulomas in the meninges. An asymptomatic lesion in the choroid plexus, with prolonged uptake of Gd-DTPA is described for the first time.

Bone Diseases↗
PubMed1990

[MR tomography and computer tomography of alcohol-induced brain tissue changes].

Results of MRI in five alcoholics suffering from acute neurologic disorders such as ataxia, ophthalmoplegia and confusion are presented. The detection of focal cerebral lesions of high signal intensity in T2-weighted Spin-Echo- and Gradient-Echo-images in periventricular white matter, thalamus and pons combined with patients history and clinical presentation led to the diagnosis of Wernicke-Encephalopathia and Pontine Myelinolysis. MRI was far more sensitive compared with CT.

Adult↗
PubMed1989

[MR tomography, CT and angiography of vascular malformations of the central nervous system].

The findings on MR tomography in 31 vascular malformations of the central nervous system are described; 26 of these had angiography and 24 were examined by CT. There were 19 A-V angiomas, 7 cavernomas and 5 large aneurysms. MRT provided a correct diagnosis in 29 out of 31 cases, angiography succeeded in 19 out of 26 cases and CT in 20 of 24. MRT was superior to CT and angiography. Nevertheless, it cannot replace arteriography, since this is the only method for demonstrating the vascular supply of angiomas and small aneurysms can be demonstrated only by arteriography.

Angiography↗
PubMed1989

[MR tomography following craniocerebral trauma: comparison with computed tomography, electroencephalography and neurologic status].

56 patients with head and brain trauma and in coma were studied prospectively by means of MRT, CT, EEG and neurological examination. All patients had initial CT and EEG admission. MRT showed that in our patients morphological return to normal was the exception. Patients with head and brain injuries should be examined by MRT during the course of their illness. The use of special sequences, such as gradient-echo sequences for the diagnosis of haemorrhagic contusions, is indicated. CT should be retained for evaluating bone injury and cerebral damage during the acute stage.

Adult↗
PubMed1989

[NMR tomography of the brain in patients on long-term dialysis].

24 patients on long-term dialysis, aged between 20 and 78 years, were examined by brain MRT and CT. Both methods showed equally atrophic changes in the brain; in particular, cortical atrophy appears to increase with increasing duration of dialysis. MRT shows small hyperintensive areas in the white matter which cannot be seen on CT. Hypointensive areas on MRT are not due to calcification, but pathological deposition of metals, such as iron, must be considered.

Adult↗
PubMed1989

[Relaxation time measurements in the differential magnetic resonance tomographic diagnosis of liver tumors].

T1-weighted IR sequences and T2-weighted SE sequences and combined SE/IR sequences were carried out in 62 patients with malignant and 50 patients with benign liver tumours and the T1 and T2 relaxation times were measured. IR sequences proved the most sensitive method for imaging focal liver lesions and providing good contrast between liver tissue and tumour. For lesions above 1.5 cm, quantitative MRI achieved an accuracy better than 95% in distinguishing between haemangiomas and malignant lesions. Routine quantitative measurements of relaxation times were sufficiently reproducible for clinical use.

Carcinoma, Hepatocellular↗
PubMed1989

[Bone marrow scintigraphy and magnetic resonance tomography in plasmacytoma].

In 17 patients suffering from plasmocytoma bone marrow scintigraphy (BMS), and magnetic resonance tomography (MRT) was performed. RES expansion in the extremities was found by both methods, MRT also visualized a diffuse infiltration of the marrow. In that location, cold lesions in BMS correspond to yellow marrow. In the pelvis, however, cold lesions are due to tumor involvement. Both methods offer additional diagnostic opportunities and may in the future allow to expand the time intervals between routinely performed iliac crest biopsies.

Aged↗
PubMed1988

[MR tomography of non-tumor diseases of the brain and cervical cord].

118 examinations were carried out for non-tumorous diseases of the brain and cervical cord. The sensitivity of MRT was analysed and compared with 77 cases where CT had been performed or with sonography in children. MRT showed an abnormality in 80%, whereas CT or sonography lead to a diagnosis in only 43%. Because of the significantly higher sensitivity of MRT, this should be the primary means of examination for this type of case.

Acquired Immunodeficiency Syndrome↗