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J Assheuer

Publications and source records attributed to J Assheuer.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Nuclear magnetic tomography of the meniscus in asymptomatic probands].

In 82 asymptomatic subjects aged 8-62 years we evaluated the menisci by MRI [1.0 tesla; SE (spin-echo) 700/20, PS (partial saturation) 500/10, STIR (Short-Time-Inversion-Recovery-Sequence) 1600/130/30]. The meniscus was graded by means of a standard classification (grades 0-4). In SE sequences we found grade 0 in 45.5% of all cases, grade 1 in 33.2%, grade 2 in 16.1%, grade 3 in 4.5%, and grade 4 in 0.7%. In PS sequences we found grade 0 in 23.9%, grade 1 in 27.5%, grade 2 in 31.5%, grade 3 in 15.9%, and grade 4 in 1.1%. In STIR sequences we found grade 0 in 56%, grade 1 in 25.4%, grade 2 in 11.1%, grade 3 in 6%, and grade 4 in 1.6%. Correlation of meniscus degeneration with subjects' age showed relation of meniscus degeneration with subjects' age showed relation of meniscus degeneration with subjects' age showed an increase of grade 3 and grade 4 lesions with advancing age. Subjects older than 50 years presented grade 3 and 4 lesions in the SE sequence in 28.5% of the cases, in PS sequences in 40.7% of the cases, and in STIR sequences in 25% of the cases. MRI shows meniscal lesions in a significant proportion of asymptomatic patients, especially among subjects older than 50 years. The orthopedic surgeon has to test whether the clinical findings in patients with knee complaints coincide with the results of MRI.

Adolescent↗
PubMed1992

Radicular avulsion resulting from spinal injury: assessment of diagnostic modalities.

The diagnostic utility of imaging techniques in injuries to the intramedullary and subarachnoid portions of the brachial plexus, with possibly complete avulsion of one or more nerve roots from the spinal cord and extramedullary meningocoele was compared in 18 patients studied by unenhanced computed tomography (CT), cervical myelography, myelographic CT (MCT) and magnetic resonance imaging (MRI). Emphasis was placed on the lesions of the subarachnoid roots. CM was the only diagnostic modality to show avulsion of 18 nerve roots and their levels in 8 patients (100% = gold standard), and to verify 2 incomplete avulsions. MCT reliably revealed 8 of 18 (45%) and MRI 1 out of 18 (6%) avulsions. Myelography with MCT showed intact subarachnoid nerve roots in 10 additional patients. MRI and MCT (16 out of 16 = 100%) were superior to myelography (14/16 = 88%) for demonstrating 16 traumatic meningocoeles in 8 patients; follow-up MRI (6-24 months) showed no increase in their size. We recommend a subsequent CT to role out fracture to the spinal column; MRI should provide significant information concerning oedema or haemorrhage in the spinal cord. Myelography with segmental MCT is performed to differentiate pre- from post-ganglionic lesions, data which are essential for deciding whether exploration of the plexus or a motor substitution operation is indicated.

Adolescent↗
PubMed1992

[Possibilities of nuclear magnetic resonance tomography in diagnosis of osteochondrosis dissecans of the knee joint].

20 patients who suffered from osteochondrosis dissecans in the knee were examined by x-ray and MRI. Afterwards all joints were evaluated by arthroscopy. On plain x-ray the judgement of joint cartilage is not possible. With the use of MRI, the hyaline cartilage can be documented. Even without any visible changes on x-ray, MRI clearly reveals pathologic bone patterns. Comparing areas of sclerosis on x-ray with MRI changes, the real diameter of osteochondrosis dissecans can only be seen on MRI.

Arthroscopy↗
PubMed1992

[Nuclear magnetic resonance tomography diagnosis of changes in the glenoid process in patients with unstable shoulder joints].

UNLABELLED: In 4 fresh specimens and in 14 healthy volunteers we studied normal anatomy of the glenoid labrum by MRI. In a total of 124 patients we examined the shoulder joints by MRI. 69 patients had any kind of subacromial pathology. 55 patients showed a glenohumeral instability. All MRI findings were compared with the surgical findings during arthroscopy and during open surgery. 44 patients showed a recurrent anterior instability, 7 patients showed a multidirectional instability, 2 patients showed a posterior instability, and 2 patients presented acute anterior dislocation. We found significant variability in the labral shape as well as significant variability of anterior capsular attachment. The pathologic changes of the glenoid labrum were classified in four different types. In 78% we found a concomitant Hill-Sachs lesion of various diameter. 5 patients suffered from an additional complete rotator cuff tear. Compared to the intraoperative findings MRI had a sensitivity of 95%, a specificity of 94%, an accuracy of 94%, a positive predictive value of 91%, and a negative predictive value of 96% in detecting labral pathology. CLINICAL RELEVANCE: Presenting a high diagnostic value for detecting Bankart lesions, MRI may replace other diagnostic modalities like CT-arthrography.

Humans↗
PubMed1992

Comparison of MRI, CT and angiography in cerebral arteriovenous malformations.

Computed tomography (CT), magnetic resonance imaging (MRI) and cerebral angiography were performed in 30 patients with cerebral arteriovenous malformations (AVMs). Clinical data and radiographic findings are presented. The diagnostic values of CT and MRI are compared. 25 of 30 AVMs were seen on CT-scans, 27 on MR-images, 26 by angiography. Typical CT-findings were irregularly hyperdense areas with spotlike contrast enhancement. 4 out of 5 AVMs not depicted by CT were diagnosed for tumor, in one case the malformation was hidden by a hematoma. MRI mostly showed the AVM as round or oval lesions with spongelike structure of low signal intensity in T1-weighted sequences or as single enlarged vessels. The 26 AVM revealed by angiography presented typically enlarged vessels; in 2 cases angiography was without any pathological findings, 2 cases showed signs of a space occupying lesion. The results confirm that MRI is superior to CT in detecting and recognizing AVM. Its strength lies in the possibility to detect abnormal vessels even in presence of fresh or older hematoma, and in the precise information on size and location of the AVM. In our series, MRI and CT-scans together showed 28 of 30 AVMs, the remaining 2 cases were not seen with angiography either but only proven histologically. Although today MR-angiography is able to provide three dimensional images of blood vessels, it cannot yet replace angiography in the exact study of the vessels which is required for surgical planning.

Adolescent↗
PubMed1991

[Nuclear magnetic resonance tomography of changes in the supraspinatus tendon in impingement syndrome of the athlete].

UNLABELLED: In 13 athletes with impingement-syndrome we evaluated the shoulder joints by MRI. We found significant changes at the bone-tendon junction of the supraspinatus tendon at the major tubercle. There were no intratendinous ruptures. The site of the pathologic changes at the insertion of the supraspinatus tendon may be caused by a tendinosis. Other reasons for the impingement-syndrome are discussed. According to our results an insertional tendinosis may be the reason for impingement-syndromes in athletes. CLINICAL RELEVANCE: Differentiation of impingement-syndrome may lead to a therapy based on the pathology. A subacromial decompression with resection of the coracoacromial ligament and anterior acromioplasty may not be of benefit to patients with insertional tendinosis of the supraspinatus tendon.

Adult↗
PubMed1991

[Concomitant occult osseous injuries in knee joint injuries].

In 28 patients with different knee injuries, we documented intraosseous lesions by MRI, although on plain X-rays no abnormality had been discovered. The intraosseous abnormalities seen by MRI were classified into four categories. 1. Cancellous bone oedema: this type of lesion showed a decrease of signal on T1 weighted images with irregular borders. These irregular areas were located in the epiphysis and sometimes even in the metaphysis. On T2 weighted images these areas showed an increased signal, which was even better visualised on short time recovery sequences. 2. Subchondral fracture with involvement of cortical bone: In these cases the involved area even reached the subchondral cortex. The fracture line could be visualised on T1- and T2-weighted images. 3. Osteochondral fractures: In two patients we found typical osteochondral fractures with a minimal displaced small fragment. 4. Subchondral sclerosis: In these cases there was a decrease of the signal on T1-weighted images, located directly adjacent to the subchondral cortical bone, without a fracture within the cortical bone and without any increase of signal on T2-weighted or STIR-images. According to our experience, isolated decrease in the signal within the subchondral cancellous bone adjacent to the knee joint, with an increased signal in STIR sequences can be taken as indirect signs for a traumatic lesion. These intraosseous lesions have a high coincidence with ligament injuries of the knee joint.

Adolescent↗
PubMed1991

[Proton spin and computerized tomography in ligament injuries of the knee joint].

UNLABELLED: In a prospective study we evaluated the use of cat-scan an MRI in 106 patients with chronic complaints and acute injuries of the knee joint. All patients went to surgery afterwards. A total of 30 patients suffered from acute or chronic ligament ruptures. There were 20 ACL ruptures, 2 PCL ruptures, 3 MCL ruptures, and 2 LCL ruptures. In patients with ACL ruptures the MRI had a sensitivity of 80%, a specificity value of 80%, and a negative predictive value of 95%; whereas cat-scan had a sensitivity of 90%, a specificity of 95%, an accuracy of 94%, a positive predictive value of 82%, and a negative predictive value of 98%. All complete ACL ruptures we correctly diagnosed. However, 4 partial ACL ruptures were missed by MRI and 2 partial ruptures were missed by cat-scan. All other ligament ruptures (PCL, MCL, LCL) except one MCL rupture were correctly diagnosed by MRI as well as by cat-scan. CLINICAL RELEVANCE: In this study cat-scan and MRI proved to have a very high negative predictive value. Having a negative result in one of these imaging techniques means that a rupture of a ligament is highly unlikely. This may have influence on the number of unnecessary invasive arthroscopic procedures.

Anterior Cruciate Ligament Injuries↗
PubMed1991

[Value of computerized tomography and nuclear magnetic resonance tomography in preoperative diagnosis of meniscus lesions and ligamentous lesions of the knee joint].

In a prospective study, 53 patients with chronic complaints and acute injuries of the knee joint, were evaluated by clinical examination, CT-scanning and magnetic resonance imaging (MRI). Subsequently, arthroscopy or an open surgical procedure was performed. A total of 21 patients suffered from meniscal lesions. There were 17 ruptures of the medial and 4 ruptures of the lateral meniscus. In patients with meniscus ruptures, the sensitivity of both MRI and CT-scan was 86%, whereas the specificity of MRI was slightly lower than that of CT-scan. The accuracy and the predictive value were also slightly lower, although the difference was not significant. Fifteen patients suffered from acute or chronic ligament ruptures. In patients with anterior cruciate ligament (ACL) ruptures, all complete ACL ruptures had correctly been diagnosed by CT and MRI. Two out of four partial ACL ruptures were missed by MRI; only one was missed by CT-scan. Three medial collateral ligament ruptures were documented by MRI and two by CT-scanning. The high negative predictive value of CT and MRI can realize a reduction of the amount of diagnostic arthroscopies.

Anterior Cruciate Ligament↗
PubMed1991

[Nuclear magnetic resonance and computerized tomography in meniscus injuries of the knee joint].

In a prospective study we evaluated the use of CAT scan and MRI in 53 patients with chronic symptoms and acute injuries of the knee joint. All these patients subsequently underwent surgery. A total of 21 patients had acute or chronic meniscus ruptures. The sensitivity of MRI was 86% (medial: 88%, lateral: 75%), its specificity, 95% (medial: 92%, lateral: 98%), its accuracy 93% (medial: 91%, lateral: 96%), its positive predictive value of 82% (medial: 83%, lateral: 75%), and its negative predictive value 96% (medial: 94%, lateral: 98%); CAT scan had a sensitivity of 86% (medial: 88%, lateral: 75%), a specificity of 97% (medial: 94%, lateral: 98%), an accuracy of 94% (medial: 93%, lateral: 96%), a positive predictive value of 86% (medial: 88%, lateral: 75%), and a negative predictive value of 97% (medial: 94%, lateral: 98%). In this study CAT scan and MRI proved to have a very high negative predictive value in the diagnostic of meniscal lesions. A negative result with one of these imaging techniques means that a rupture of a meniscus is highly unlikely. This may avoid unnecessary invasive procedures such as arthrotomies or arthroscopic examinations.

Arthroscopy↗
PubMed1990

New aspects of lumbar disc disease. MR imaging and histological findings.

Magnetic resonance imaging (MRI) and plain X-ray and CT studies were performed in patients with a history of lumbar back pain due to spinal disc disease. Spin-echo pulse sequences (SE), phase-contrast techniques (partial saturation sequences with delayed readout, PS), and fat-suppressing inversion recovery sequences (STIR) were employed. In 74 of 325 patients, PS and STIR images displayed vertebral marrow changes adjacent to the end-plates of the affected segments. Bacterial infection, however, could be excluded. In six patients histological diagnosis showed substitution of hematopoietic marrow by fatty tissue, cartilaginous particles, degeneration of fat cells, and an increase in extracellular fluid with different components. The etiology is still unclear, but a correlation with lumbar disc disease is demonstrated. These vertebral marrow changes were best displayed with STIR and phase-contrast MR sequences, both providing contrast changes superior to T2-weighted SE techniques.

Adolescent↗
PubMed1990

[Standardization of cerebral imaging by magnetic resonance tomography].

The complex three-dimensional organisation of the human brain, as well as the numerous variables involved in modern imaging techniques, make it necessary to introduce guidelines for the interpretation of the topographical localisation and allocation of normal cerebral structures and pathological processes. In a historical overview of the methods used for precise localisation we introduce some models that can be used as diagnostic aids. As supporting means in the MRI we suggest the standardisation of the imaging by application of this model. The methodological procedures of its use in the MRI are shown in detail. Finally the advantages and disadvantages of this model are discussed with regard to its possible applications in imaging systems such as MR. The imaging standards for intra-interindividual and inter-methodologic comparison in routine investigations are emphasized in particular.

Brain↗
PubMed1990

[Perspectives of a function study of the TMJ with magnetic resonance imaging].

Magnetic resonance imaging of the temporomandibular joint is usefull in the examination of the stomatognathic system. In order to visualize the components of the temporomandibular joint during dynamic jaw movement and to improve the diagnostic accuracy of temporomandibular joint disorders we present remedies for magnetic resonance imaging and discuss their possibilities and limits how you can stabilize the jaw in an interesting functional position during examination period.

Humans↗
PubMed1990

[Cardinal criteria for TMJ assessment in sagittal magnetic resonance imaging].

In diagnosis and therapy of temporomandibular joint disorders magnetic resonance imaging is an ideal method for visualizing hard and soft tissue structures of the temporo-mandibular joint in a short examination. In this paper we present the main criteria used in interpretating magnetic resonance images and explain these criteria in patient cases.

Cartilage, Articular↗
PubMed1989

Experimental transplantation gliomas in the adult cat brain. 2. Pathophysiology and magnetic resonance imaging.

In adult cats experimental brain tumours were produced by stereotactical xenotransplantation of the rat glioma clone F 98 into the internal capsule of the left hemisphere. Two to four weeks after transplantation tumours and peritumoural oedema were investigated by magnetic resonance imaging (MRI), electrophysiological recording and analysis of tissue content of water, electrolytes and extravasated serum proteins. Spherical tumours with a diameter of about 10 mm developed at the injection site and were surrounded by massive white matter oedema. Water content in peritumoural white matter increased from 2.63 +/- 0.17 to 3.65 +/- 0.19 ml/g d.w. (means +/- SD), sodium from 187 +/- 11 to 351 +/- 55 mueq/g d.w. and calcium from 7.4 +/- 1.1 to 13.3 +/- 1.3 +/- 1.3 mueq/g d.w. Potassium and magnesium did not change. Oedema development was associated with the extravasation of 18.0 +/- 16.8 mg/g d.w. albumin and 15.8 +/- 12.2 mg/g d.w. immunoglobulin. The calculated electrolyte content of oedema fluid approximated that of plasma but the serum protein content was about 40% lower. The ratio of low (albumin) to high (immunoglobulin) molecular weight proteins was the same in blood and oedema fluid. It is, therefore, concluded that peritumoural oedema consist of two components, a whole plasma extravasate and a protein-free ultrafiltrate. Peritumoural oedema could be clearly detected by MRI but differentiation between tumour and oedema was only possible after contrast enhancement with gadolinium-DTPA. The ratios of the intensities of the MR signal correlated linearly with the water content within white matter. MRI, in consequence, allows quantification of oedema provided a reference area with normal water content is present.

Animals↗
PubMed1989

[Magnetic resonance tomography flow measurement in cerebral arteriovenous angioma].

A case of cerebral AVM associated with Klippel-Trenaunay Syndrome is presented where Magnetic Resonance (MRI) flow measurement revealed details of the shunt from the cerebral arterial system. The AVM was supplied by two arteries, the main flow came from the left vertebral and internal carotid artery. The arterial blood supply of the AVM was about 268 ml/min, the av-shunt flow was about 18% of the whole carotid and vertebral upstream flow.

Adult↗