[Mechanical stimulation of venous blood flow in below-the-knee plaster cast]. / Mechanische Förderung des venösen Rückflusses im Unterschenkelgipsverband.

Physical methods became recently more important as an alternative to anticoagulation for prophylaxis of thromboembolism and were studied for their efficacy. The AV-impulse-system proved efficient in reducing thromboembolic complications in patients undergoing hip surgery by increasing the return of venous blood in the deep veins of the leg. In a preclinical trial we studied the influence of the AV-impulse-system and of active forefoot movement on venous blood return in 12 lower extremities of 6 healthy individuals immobilized in below the knee plaster casts. Our results show a significant increase in venous blood flow caused by the AV-impulse-system (p < 0.05) and by active forefoot movements (p < 0.05). Prevention of thromboembolic complications in trauma and orthopaedic patients immobilized in plaster cast seems possible by using the AV-impulse-system which significantly increases the venous blood flow independent from patient compliance.

Paranasal sinuses and nasopharynx CT and MRI.

Neoplastic disease of the nose, paranasal sinuses, the nasopharynx and the parapharyngeal space requires thorough assessment of location and extent in order to plan appropriate treatment. CT allows the deep soft tissue planes to be evaluated and provides a complement to the physical examination. It is especially helpful in regions involving thin bony structures (paranasal sinuses, orbita); here CT performs better than MRI. MRI possesses many advantages over other imaging modalities caused by its excellent tissue contrast. In evaluating regions involving predominantly soft tissue structures (ec nasopharynx and parapharyngeal space) MRI is superior to CT. The possibility to obtain strictly consecutive volume data sets with spiral CT or 3D MRI offer excellent perspectives to visualize the data via 2D or 3D postprocessing. Because head and neck tumors reside in a complex area, having a 3D model of the anatomical features may assist in the delineation of pathology. Data sets may be transferred directly into computer systems and thus be used in computer assisted surgery.

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.

[Rational imaging strategies in laryngeal diseases]. / Rationelle bildgebende Strategien bei Kehlkopferkrankungen.

Clinical information is indispensable for swift and cost-effective clarification of diseases of the larynx. While quality clarification of neurological changes in the area of the posterior cranial fossa and in the course of the vagus nerve as a cause of glottis malfunction is possible with MRI, localized disease of the larynx can more effectively be assessed with low-artifact CT. In the particularly difficult assessment of the post-operative larynx, a recurrence can be diagnosed only after a baseline study has been carried out after the end of therapy. With knowledge of the pretherapeutic findings, the findings immediately post-therapy, and the operation technique used, the optimal CT examination, which can be carried out quickly, will be able to provide more information about recurrence.

Imaging of the normal and pathological orbit.

Computerized techniques (CT and MRI) allow precise delineation of orbital anatomy and abnormalities. Orbital tumors are nicely depicted by these methods; various examples are illustrated in this article, with discussion of the respective impact of CT and MRI. Orbital inflammation and foreign bodies usually represent radiologic emergencies, prompting use of CT (frequently) or MRI (occasionally). Digital subtraction angiography (DSA) is indicated for diagnosis of vascular changes (mainly carotid-cavernous fistula, aneurysms, angiomas, Rendu-Osler disease). Angiography is usually done to ascertain the possibility of an interventional procedure. Orbital vascular interventions include re-canalization of occluded vessels, and embolization of pathologic (tumorous or post-traumatic) vessels.

ACL reconstruction by patellar tendon. A comparison of length by magnetic resonance imaging.

In 50 knees the length of the anterior cruciate ligament (ACL), the patellar tendon, and the distance between the tibial tuberosity and the femoral origin of the ACL were evaluated by means of three-dimensional magnetic resonance imaging (MRI), which permits subsequent reconstruction of any sectional view. The measurements showed that the patellar tendon was always markedly longer than the ACL (mean 14.4 mm), but always shorter than the distance between the tibial tuberosity and the femoral insertion of the ACL (mean 19.2 mm). The mean lengths of the ACL and the patellar tendon were 38.2 mm and 52.6 mm, respectively. The mean distance between the femoral ACL origin and the tibial insertion of the patellar tendon was 71.8 mm. These results demonstrate that a distally based patellar tendon autograft alone (with the patellar bone block but without extension into the periosteum of the patella or the quadriceps tendon) cannot be placed anatomically correctly to the isometric femoral insertion of the ACL. When the patellar tendon is used for ACL reconstruction, it must be implanted as a free autograft. Nevertheless, considerable variations of length must be taken into account.

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.

[Promoting venous return in plaster cast by AV impulse system. A preclinical study]. / Förderung des venösen Rückstroms im Liegegipsverband durch das AV-Impulssystem. Eine präklinische Untersuchung.

A new pneumatic compression pump--the AV-impulse system--causes increased return of venous blood from the lower limbs to the heart and increases total blood flow in the lower limbs by emptying the plantar venous plexus. Up to date there exist no experiences with using this system in plaster cast. We studied the maximum venous blood flow, the venous blood flow per minute and the venous diameters above the popliteal and femoral vein by duplexsonography in 12 lower limbs of 6 healthy persons before and after applying below-the-knee plaster casts. After applying the plaster cast we observed a slight increase in venous diameter (p = 0.02). By using the AV-impulse-system we observed a significant increase in maximum venous blood flow and venous blood flow per minute (p < 0.05). We demonstrated a significant increase of venous blood return in the deep veins of the lower limbs after applying a lower limb plaster cast by using the AV-impulse-system. These results indicate the possible benefit of using the AV-impulse-system as a physical method of thromboprophylaxis in orthopaedic and trauma patients with plaster cast immobilisation of the leg.

[CT-guided punctures in the area of the spine. The "fluorotechnique" as localization method]. / CT-gesteuerte Punktionen im Wirbelsäulenbereich. Die "Fluorotechnik" als Lokalisationsmethode.

The increased anatomical resolution of the Computed Tomography allows the localized excision of tissue malformation even less than 5 mm in diameter. Within difficult areas of the body, e.g. the spine, it is possible to reach intra- as well as extraosseous lesions with high accuracy. Results and technique of puncture are reported in 31 patients with unclear diagnosis or therapy (Neurolysis). In 24 cases diagnosis was established or therapy was successful, in 2 cases the result was false negative. In 5 cases the tissue was non diagnostic. According to the low number of complications (n = 1) a repeated study would have been possible.

[Magnetic resonance tomography and histopathologic findings after muscle denervation. A comparative animal experiment study during a two month follow-up]. / Kernspintomographische und histopathologische Befunde nach Muskeldenervierungen. Eine vergleichende tierexperimentelle Studie während einer zweimonatigen Verlaufsuntersuchung.

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.

A tumour derived from Ebner's glands: microcystic adnexal carcinoma of the tongue.

Microcystic adnexal carcinoma (MAC) is known as an infiltrating but non-metastasizing tumour of the skin, that derives from sweat glands or follicular epithelium. We report on a rare case of MAC of the tongue. The patient had noticed the tumour for two years with slowly increasing dysphagia but no other symptoms of an oropharynx carcinoma. Histological and immunohistochemical analyses showed a similarity between the tumour derived from Ebner's glands of the tongue and MAC of the sweat glands.

[Differential diagnostic evaluation of a dysfunctional kidney transplant by magnetic resonance tomography]. / Differentialdiagnostische Abklärung des dysfunktionellen Nierentransplantats durch die Kernspintomographie.

Immediate diagnosis of rejection is essential for the prognosis of a renal transplant. To differentiate between rejection and acute tubular necrosis, 48 examinations (31 patients) were evaluated by Magnetic Resonance Imagining and Duplex Doppler ultrasound, and compared to the clinical outcome and histology. Sensitivity of MRI and Duplex Doppler was 82% (14/17), specificity was 77% (24/31) and 84% (26/31), respectively. Even when the results of both methods matched well, due to the extensive financial and technical efforts MRI may only be used as an additional tool for diagnosis.

[Swelling of the sternoclavicular joint]. / Schwellungen am Sternoklavikulargelenk.

From 1990 through 1993 nine patients presented with unexplained swelling of the sternoclavicular joint. In some cases a tumor was suspected. The clinical histories included trauma with injury of forearm and wrist or strain on the shoulder girdle without acute onset of any symptoms in the sternoclavicular joint. In trauma cases the time from injury to onset of symptoms was between 1 day and 1 year (median 5 weeks). CT studies demonstrated widening of the joint space in two cases, thickening of the pectoral muscle in six cases and thickening of capsule and ligaments in five cases. In one case arthroplasty of the sternoclavicular joint was performed and in a second we performed a biopsy. The remaining cases were not treated. Other differential diagnoses to be considered in the case of a swelling of the sternoclavicular joint are listed.

[MRI results in experimental muscle injuries]. / MRT-Ergebnisse bei experimentellen Muskelverletzungen.

We performed an incision of standardized size and location on the suprascapularic muscle of 18 rabbits by a stab with a scalpel and measured the signal intensity of the muscle 2, 5, 11, 21, 35 and 64 days after injury (3 rabbits on each day). We did not find any detectable changes in the MRI pictures but a characteristic graph of the calculated T2-times (a mathematical procedure of the MRI software). The MRI changes correlate with the histopathological changes after muscle injury. The MRI method allows the evaluation of minor muscle trauma by the detection of a changed liquid content by using calculated T2 times.

[Magnetic resonance tomography evaluation of the lower limb after compartment syndrome]. / Magnetresonanztomographische Beurteilung des Unterschenkels bei Zustand nach Kompartmentsyndrom.

For the purpose of follow-up of the disease as well as the availability of magnetic resonance imaging (MRI) as a method for diagnosing soft tissue changes 20 patients with imminent and manifest compartment syndrome were examined for their fluid content of the lower limb. Considering the normal side as well as 10 healthy volunteers a significant reduction of fluid content was diagnosed in the manifest compartment syndrome after fasciotomy in the late phase of disease (r = 0.49, p > 0.005, n = 29). This was interpreted as a sign of fibrosis. The patients with imminent compartment syndrome and fasciotomy (r = 0.83, p > 0.001, n = 19) demonstrated no significant changes compared to the normal volunteers (r = 0.91, p > 0.001, n = 40) as well as the normal compartments of the diseased lower extremities (r = 0.85, p > 0.001, n = 32). MRI is a useful method in the examination of soft tissue changes and underlines the importance of an early fasciotomy in case of imminent compartment syndrome.

MR relaxometry: estimating overhydration in renal failure.

An MR method is described for estimating overhydration in patients suffering from renal failure. In 29 healthy volunteers, the fat content of a selected slice of the lower limb was correlated to the overall T1-relaxation time (r = -0.97, p < 0.000001). When compared with the normal T1 of the voluntary group, delta T1 was calculated having regard to the individual fat content in 74 MR studies of 22 overhydrated patients. MR results were correlated with the difference between clinically estimated dry and the actual body weight (r = 0.6, p < 0.000001). In an intraindividual follow-up (11 studies) MRI was shown to provide good correlation to the actual body weight (r = 0.9, p < 0.0005) and fluid balance (r = 0.87, p < 0.001).

[The traumatized shoulder in computerized and magnetic resonance tomography]. / Die traumatisierte Schulter in der Computer-und Magnetresonanztomographie.

Diagnosis of traumatic changes of the shoulder can be achieved by several invasive and nonivasive radiological procedures allowing visualization of bony and/or soft tissue structures. With reference to 74 shoulder examinations CT, CT-arthrography, and MRI were reviewed and their value for further treatment assessed. Since joint effusions occurred in nearly all cases of glenoid and rotator cuff lesions, a cost-effective strategy for diagnosing traumatic changes of the shoulder is presented.