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Biomedical subjects

M Nägele

Publications and source records attributed to M Nägele.

At least 19 recordsLinked to original sources
PubMed1998

Changes of sonographic, magnetic resonance tomographic, electromyographic, and histopathologic findings within a 2-month period of examinations after experimental muscle denervation.

This study compares sonographical, histopathological, magnetic resonance imaging (MRI), and electromyographical (EMG) findings following acute muscle denervation. We performed an experimental denervation of the supraspinatus and infraspinatus muscles on 35 New Zealand white rabbits by segment resection of the suprascapular nerve. The sonographical appearance of the supraspinatus muscle was followed and documented at short time intervals within a 2-month follow-up period. The sonographical, histopathological, and MRI changes due to denervation suggest a regular pattern. Apart from the reduction of the muscle diameter, there were considerable sonographical signs of denervation with an increase of echointensity and inhomogenicity of echotexture that appeared on day 14 after injury, and progressed continuously with time. MRI revealed a remarkable increase in signal intensity 3 weeks after denervation and reproducible T2 times. Pathological spontaneous activity on EMG could also be detected from day 14 after injury. Conventional histopathological staining methods (H&E, NADH, ATPase, basic and acid phosphatase) confirmed denervation and absence of reinnervation. The first nonspecific histopathological changes were seen 11 days after denervation in the form of moderately atrophic fibers. Typical histopathological signs of denervation appeared 3 weeks after nerve dissection. In summary, EMG, ultrasound, MRI, and histopathology each showed first abnormalities after about 2 weeks. In addition to EMG, sonography and MRI can document the course of muscle atrophy and mesenchymal abnormalities in neurogenic muscle lesions.

Animals↗
PubMed1997

Sonography and MRI of experimental muscle injuries.

After sonographical examination with a 7.5-MHz linear array scanner, we created an experimental muscle injury of known site and location on 28 New Zealand white rabbits by stabbing them with a scalpel in the supraspinatus muscle. The changes in the healing process were followed and documented by sonography and magnetic resonance imaging (MRI) before and 2, 5, 11, 14, 36 and 64 days after injury. The changes in sonography and MRI followed a regular course. Ultrasound revealed an echo-poor area after injury with ever increasing echogenicity from the 14th day. Strong reflexes were found after 2 months. MRI showed few changes, only a slight increase of signal intensity, but a characteristic curve of calculated T2-times (a program of the MRI software). The interpretation of the sonographical picture in histopathological terms remained limited. The development of a hematoma and of fibrous scars can be followed up by sonography, but it is not possible to determine the point of time after injury very accurately. Nevertheless, sonography is a method of great value in the diagnosis of muscle injuries and, given certain limits, in the follow-up of the healing process, too. The significance of MRI can be increased by calculations with the implemented software, as in our study calculated T2-times produced a characteristic curve reflecting the shift of fluids after muscle injury.

Animals↗
PubMed1996

[Magnetic resonance tomography and histopathologic findings after muscle denervation. A comparative animal experiment study during a two month follow-up].

Recently, MRI was described as a method in the diagnosis of changes of muscle after acute neurogenic muscle atrophy. This study was performed to compare MRI results with myopathological findings, to document the appearance of the MRI changes and to check the sensitivity of this method. We performed a segment resection of the suprascapular nerve resulting in a denervation of the supraspinatus and infraspinatus muscles on 18 Newzeeland white rabbits. MRI changes were followed and documented for two months in short periods of time. The results were compared with histological findings. In myopathology and MRI we found systematical changes: Apart from the reduction of the muscle diameter visual assessment revealed increased signal intensities on the 21st and 35th examination day after denervation. On the 2nd, 5th, 11th and 64th examination day signal intensities were normal. The changes were represented by calculated T2 times, too.

Animals↗
PubMed1995

[DIL vena cava filter. Initial experiences in 15 patients].

DIL filters were permanently inserted through the cubital vein, using a 7-F catheter, in 15 patients and were followed up for six months in 12 patients. One filter could not be opened and 4 others were only partly open. Clinically there were no recurrences of pulmonary emboli. There were no complications from the correctly placed filters. Amongst the 4 incompletely expanded filters, two caused perforation of the cava, in one the cava thrombosed and in another the filter migrated to the bifurcation of the pulmonary artery. It follows that unexpanded filters should not be placed in the cava. Measurements in 10 patients showed the cava reduced to less than 10 mm lumen. In two cases the reduction of lumen was only slight, measuring more than 15 mm. The effect of the reduction in the lumen remains to be compared with that achieved by other filters.

Aged↗
PubMed1994

Magnetic resonance imaging of skeletal muscles in idiopathic inflammatory myopathies of adults.

The purpose of the study was to describe typical MRI findings in various types of idiopathic inflammatory myopathies in adulthood and to correlate the MRI with histopathological and electromyographic findings, and the serum creatine kinase (CK) activity. A third goal was to assess the diagnostic value of the use of gadolinium-DTPA (Gd-DTPA). Fifty-eight patients (35 women, 23 men), aged 21-83 years (median age 59 years), suffering from idiopathic myositides (13 with acute and 45 chronic diseases; 25 with polymyositis, 14 with dermatomyositis, 8 with granulomatous and 11 with inclusion body myositides) were examined with MRI. Seventeen of them received an intravenous infusion of Gd-DTPA. Histopathological and MRI findings of 21 muscles of 18 patients were compared. MRI of skeletal muscles showed abnormal signal intensities in 56 (96.6%) of the 58 patients. MRI abnormalities were found more often than elevated CK activity (P < 0.001). The hyperintensity of T2-weighted images was more conspicuous than on T1-weighted images in 26 (44.8%) patients, indicating oedema-like abnormalities. MRI of 50 (86.2%) patients showed fat replacement. In acute myositides, oedema-like abnormalities were more often visible and in muscle lipomatosis less often visible than in chronic diseases (P < 0.05 each). In dermatomyositis oedema-like abnormalities were more and lipomatosis less frequent than in the other types of myositis (P < 0.005) and correlated with the acuteness of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Hemophiliac arthropathy of the knee joint. Gd-DTPA-enhanced MRI; clinical and roentgenological correlation].

17 patients with hemophilic arthropathy of the knee joint were studied with static and dynamic MRT before and after i.v. bolus injection of Gadolinium-DTPA (0.1 mmol/kg body weight). After contrast enhancement, synovial proliferations exhibited an increase of signal intensity (SI) on FFE and SE images of 47.7% and 37.4% respectively, whereas muscle and fatty tissue, tendons, bone marrow and joint effusion revealed only minor increase in SI. The gradient of signal intensity (ratio SI/time) of pannus was 39.6%/min. Gd-DTPA enhanced MRI studies delineate and quantify the synovial proliferations in hemophilic arthropathy. Dynamic studies in hemophilic arthropathy do not provide qualitative assessment of the inflammatory process.

Adult↗
PubMed1994

[The nitinol stent as a palliative measure in inoperable carcinoma of the esophagus and cardia. Possibilities and limitations of the procedure].

Nitinol stents were used in ten patients as palliative treatment for carcinoma of the esophagus and the cardia. Following insertion of the stent the severity of dysphagia decreased on average from 3.2 to 1.5 (on a scale from 0-4). Difficulties with stent opening and passage through the gut were found particularly in the region of metal sutures at esophago-jejunal anastomoses. One stent, which had been obstructed by mucosal folds, had to be removed and replaced. One stent which had been incorrectly placed was extended by introducing a second stent by a coaxial technique. During the period of observation, six patients died after an average of 4.6 months. The palliative effect of the stent lasted on average for eleven weeks. In two patients the tumour grew beyond the stent and in three there was tumour growth into the stent.

Adenocarcinoma↗
PubMed1993

[Rheumatoid arthritis of the wrist. Dynamic Gd-DTPA enhanced MRT].

21 patients with rheumatoid arthritis of the wrist diagnosed according to the criteria of the American Rheumatism Association were examined by dynamic MRT before and after the i.v. injection of Gd-DTPA (0.1 mmol/kg). The results were correlated with the clinical and radiological findings. The increased signal intensity of the pannus was 1.17 +/- 0.45%/sec and this differed significantly (p < 0.001) from bone marrow (0.16 +/- 0.11%/sec) and from muscle (0.25 +/- 0.16%/sec). Blood sedimentation rate correlated with the gradient of synovial proliferation (p < 0.05). There were no further statistically significant correlations between the clinical, radiological and MRT findings and the change in signal intensity from synovial proliferation as shown by dynamic MRT.

Adult↗
PubMed1992

Imaging techniques in myotonic dystrophy. A comparative study of ultrasound, computed tomography and magnetic resonance imaging of skeletal muscles.

Limb and trunk muscles of 57 patients with the juvenile or adult form of myotonic dystrophy were studied by imaging techniques (ultrasound, computed tomography, magnetic resonance imaging). Typical findings were atrophy of the tibialis anterior and triceps brachii muscles and fatty degeneration of the vastus intermedius, sartorius, tibialis anterior and soleus muscles as well as of medial head of the gastrocnemius muscle. Magnetic resonance imaging was the most sensitive technique in depicting mesenchymal muscle alterations, followed by computed tomography and ultrasound. The data support that imaging is more sensitive in detecting the myopathy than measurement of the creatine kinase activity.

Adolescent↗
PubMed1992

[Dynamic functional MRT of the cervical spine].

To obtain functional studies of the cervical spine, a device has been developed which allows MRI examinations to be carried out in five different degrees of flexion. T1 and T2* weighted FFE sequences were used. Dynamic functional MRI was performed on 5 normals and 31 patients (5 disc herniation, 4 whiplash injuries, 6 spinal canal stenoses, 14 laminectomies and spinal fusions, 2 rheumatoid arthritis). The relationship of the spinal cord to the bony and ligamentous components in different degrees of flexion was particularly well shown in whiplash injury, spinal stenosis and postoperative situations.

Cervical Vertebrae↗
PubMed1992

MRI and MRS of the skeletal muscle.

Magnetic resonance imaging and spectroscopy were performed in several types of muscular disorders. In acute stages, 31P spectra showed remarkable changes compared with normals, and T2-weighted MR images were most sensitive in delineating the pathology. Fatty degeneration of muscle in chronic diseases yielded high contrast in T1-weighted MRI and could be quantified by 1H-MRS including the chemically selective determination of proton T1 values. In order to evaluate true abundance rations of phosphorus metabolites, 31P relaxation times T1 of muscle were measured by localized inversion recovery.

Acute Disease↗
PubMed1992

["Metastasizing" Echinococcus alveolar of the liver].

We report a case of metastatic alveolar echinococcosis of the liver. There were calcifications of the liver parenchyma, and a large tumour adjacent to the porta hepatis infiltrated neighbouring structures. In addition, haematogenous metastases to the spine and foot were found. This extensive haematogenous "metastasis" is rare and may complicate diagnosis, but the typical findings in the liver should permit the correct conclusion.

Echinococcosis, Hepatic↗
PubMed1990

[Magnetic resonance tomography of scaphoid pseudarthrosis: clinical and x-ray aspects].

37 patients with non-unions of fractures of the carpal scaphoid were examined with MRI and the results compared with conventional radiographs. Advantages of MRI are the documentation of concomitant soft tissue changes in the region of the pseudarthrosis, and the early detection of osteonecrosis of one of the fragments. Advantages of conventional radiographs are the exact documentation of cancellous bone morphology and the position of the fragments.

Adolescent↗
PubMed1990

[Malignant skin and soft tissue tumors--diagnostic imaging].

Clinical evaluation of the definite size and extension of malignant skin- and soft tissue tumors is limited. Ultrasound provides a first orientation of tumor size and differentiates between solid and cystic lesions. Conventional Radiographs prove or rule out bone or periostial involvement and endotumoral calcification. If further diagnostic workup is needed MRI is the method of choice for defining the exact tumor topography, size and the affected compartments as well as the involvement of cancellous bone and bone marrow.

Diagnostic Imaging↗