Results of magnetic resonance imaging in long-term manganese dioxide-exposed workers.

Within a cross-sectional study, the neurotoxic effects of occupational exposure to manganese were examined. From a group of 90 (58 male and 32 female) workers, 11 men with long-term and high exposure to manganese dioxide (MnO2) dust were defined as exposed workers. Eleven age-matched workers of similar socioeconomic status were used as a reference group. Ambient air and biological monitoring (blood, urine, hair), clinical (Webster Rating Scale, WRS), neurophysiological (visual evoked potentials (VEP), nerve conduction velocity (NCV), electroencephalography (EEG)), and motor performance (Wiener Testsystem) examinations were performed. The pallidal index (PI), the ratio of globus pallidus to subcortical frontal white-matter signal intensity in T1-weighted magnetic resonance imaging (MRI) planes multiplied by 100, was used. For the individual body burden, manganese in blood was the most reliable biomarker. A "job-exposure matrix" for the cumulative Mn-exposure index (CEI) was calculated for each worker. The results of WRS, VEP, NCV, EEG, and motor performance tests showed no significant group differences. However, the pallidal index was increased in Mn-exposed persons. Furthermore, a statistically significant positive correlation was found between CEI and pallidal index. The results of other studies are discussed. The meaning of MRI findings for health status as well as gender-specific differences should be examined in further follow-up studies.

Computed tomography-guided endoscopic removal of an osteoid osteoma from the femur.

The case of a 19-year-old male patient who complained of dull pain in his right knee for more than 18 months and was finally diagnosed with intracortical osteoid osteoma in the femoral diaphysis is presented. A new operative method was used to locate and remove the tumor. Under spinal anesthesia with the patient in the prone position, a lateral and a posterior approach were marked with special bone cutting tubes under computed tomographic control. The usual arthroscopic instruments (punch, retrograde suction stamp) were used to remove the nidus under arthroscopic visualization, thereby avoiding the disadvantages of open excisions, such as large incisions, bone loss, long hospitalization, and risk of infection. The advantages and disadvantages are thoroughly discussed and compared with conventional surgical procedures.

[Magnetic resonance tomography of the brain in workers with chronic occupational manganese dioxide exposure]. / Magnetresonanztomographie des Gehirns bei Beschäftigten mit chronischer beruflicher Mangandioxide-Exposition.

AIM: Changes within the brain detected by MRI after chronic manganese poisoning raised the question whether morphological changes of the basal ganglia, particularly of the globus pallidus, could be detected after chronic occupational exposure to manganese dioxide. METHOD: In a cross-sectional study, healthy workers (48 male and 27 female) at a dry cell battery factory were examined. Actual internal exposure was quantified by the analysis of manganese in the blood using atomic absorption spectrometry. Chronic exposure was defined as a cumulative index (CBI) including duration of exposure, individual workplace factors, and previously measured concentrations of MnO2 in dust samples. A Philips Gyroscan T5-II (0.5 T) was used for the MRI of the brain. The following indicators were taken to ascertain possible manganese-induced changes; Pallidum-Index (PI), width of 3rd ventricle and cella media index in addition to clinical examinations. RESULTS: No cases of parkinsonism were detected in clinical examinations or by other means. The mean manganese concentration in blood was 12 micrograms/l (range: 3.9-23.3 micrograms/l). In comparison to the upper reference value of 10 micrograms/l, 42 workers (56%) had a higher body burden. A significant positive correlation between manganese levels in blood and the PI (indicated by T1-shortening) was observed as well as between the CBI and workplace-specific exposure. Brain atrophy was not detected in any of the observed cases. CONCLUSIONS: Long-term exposure to manganese dioxide dust correlates with the Pallidum-Index in MRI scans. Although the MRI findings have no current clinical relevance for individuals, further studies are necessary to evaluate specificity and potential prognostic value.

[The magnetic resonance tomographic optimization of hip joint cartilage visualization by the selection of a T1-volume gradient-echo sequence and the use of hip-joint traction]. / Magnetresonanztomographische Optimierung der Hüftknorpeldarstellung durch die Wahl einer T1-Volumen-Gradienten-Echo-Sequenz und die Anwendung einer Hüftgelenkstraktion.

PURPOSE: The purpose of this study was to examine the accuracy of MR imaging of the healthy and the arthrotically altered articular hip cartilage with in vivo and in vitro separation of femoral head cartilage and acetabular cartilage. MATERIAL AND METHODS: Images of three animal cadaver hips, 8 dissected patient femoral heads and 18 hip joints of human corpses, all either with arthrosis stage I-III or artificial cartilage defects, were compared with their corresponding anatomic sections. Additional histomorphologic examinations of the arthrotic cartilages were conducted, and MR-Imaging of 20 healthy and 21 arthrotic patient hips was performed using a specific traction method. RESULTS: Using a T1-weighted 3-dimensional gradient-echo sequence and a traction of the hip joint, it was possible due to the low-signal imaging of the joint space to separate in vivo the high-signal femoral head cartilage from the high-signal acetabular cartilage. In horizontal position of the phase-encoding parameter, minimisation of the chemical-shift artifact, mainly in the ventro-lateral areas, was accomplished. MRI measurements of the articular cartilage widths showed significant correlations (p < 0.001) with the corresponding anatomic sections. At the same time the T1 3-dimensional gradient-echo sequence of the lateral femoral head with r = 0.94 showed the lowest deviations of the measurements. It was possible with MR imaging to distinguish four cartilage qualities. CONCLUSIONS: Using these MR-examinations, an improved imaging of early stage arthrotic cartilage defects is possible, and the status of the arthrotic hip cartilage with regard to intertrochanteric osteotomy can also be assessed.

[A prospective study of early diagnosis of lunate necrosis by means of MRI]. / Prospektive Studie zur Früherkennung der Lunatumnekrose mittels Kernspintomographie.

AIM: Early recognition of lunate necrosis by means of MRI. METHODS: 49 patients with typical symptoms and normal radiographs were examined. Coronary T1 and T2 weighted images were obtained. In addition, an attempt was made to quantify fluid shift and measure of bone marrow oedema by means of extreme T2 weighting (TR 5950 ms, TE 150 ms). RESULTS: Three instances of necrosis were found; in two cases it was possible to demonstrate marrow oedema. Oedema preceding necrosis could not be demonstrated by quantifying a grey scale. CONCLUSIONS: The pattern of pain in the region of the lunate is not typical and is usually not of bone origin. Early MRT will show lunate necrosis only rarely; nevertheless, the therapeutic consequences justify the examination if pain persists for several weeks. Extreme T2 weighting for quantifying a grey scale to demonstrate early marrow oedema has not proved useful. Our experience suggests that T2 weighting is adequate and is the method of choice for the early recognition of necrosis of the lunate.

[The potentials and limits of blood-flow quantification in the peripheral arteries with MRT using a phase-mapping procedure]. / Möglichkeiten und Grenzen der Blutflussquantifizierung peripherer arterieller Gefässe mit der MRT unter Anwendung des Phase-Mapping-Verfahrens.

MRT is able to demonstrate arteries while MR angiography can quantify blood flow by a noninvasive method. In the present paper blood flow measurements were carried out in four selected cases on the basis of phase mapping. In 3 patients with lesions in the pelvis or thigh, angiography was performed in order to localise the stenosis or occlusion and this was followed by quantitative blood flow measurements. The results showed that angiography may not always provide all necessary information concerning a haemodynamically significant stenosis. The method may also be used for quantifying blood flow in the renal arteries and that it has significant advantages over the colour Doppler method.

An alternative method of three-dimensional reconstruction from two-dimensional CT and MR data sets.

Cross-sectional images for medical diagnosis and therapy are obtained by sonography, CT or MRI. We propose an alternative solution to the problem of constructing a set of cross-sectional contours from two-dimensional (2D) CT or MR data sets. The method reduces the problem of constructing a shape over the cross-sections to one of constructing a sequence of partial shapes, each of them connecting two cross-sections lying on adjacent planes. The solution makes use of a spatial mathematical formalism (Delaunay triangulation). MR investigations were carried out on different objects (hips, livers) to illustrate the two-dimensional MR data sets by the reconstruction method. The resulting images represent the original image data in a way that is more suitable for observation of 3D relationships than the conventional cross-sectional viewing model.

[The sonographic image of gallbladder adenomyomatosis]. / Sonographisches Bild der Adenomyomatose der Gallenblase.

Compared with oral or intravenous cholecystography, a diagnosis of adenomyomatosis of the gall bladder is only rarely made by ultrasound. In nine patients this diagnosis was made by sonography and confirmed at operation or by cholecystography. In four patients it was an incidental finding during ERCP. The main feature is localised or generalised thickening of the wall of the gall bladder with a smooth outer contour. In seven cases there were small cysts in the wall and in two echogenic areas in the wall. An important criterion for distinguishing between inflammatory and neoplastic mural thickening is the contractility of the gall bladder.

[Value of nuclear magnetic resonance tomography in diagnosis of infrarenal abdominal aortic aneurysms. Comparison with sonography, computerized tomography and angiography]. / Stellenwert der Kernspintomographie in der Diagnostik der infrarenalen Bauchaortenaneurysmen. Vergleich mit Sonographie, Computertomographie und Angiographie.

15 patients with asymptomatic abdominal aortic aneurysms were evaluated with magnetic resonance imaging. The results were compared to the sonographic findings in 12, the computed tomographic in 14 and the angiographic findings in 14 cases. 14 patients were operated and the diagnostic results were verified. The advantage of MRI in comparison with the other diagnostic methods is the visualization of an infrarenal segment on the coronal images, which can be anastomized with the vascular prosthesis. The evidence of this segment is important to know for the vascular surgeon to plan the operation technique. The disadvantage of MRI ist that thrombotic material and arteriosclerotic plaques were bad or not visualized. We try to estimate, which importance the MRI will get in further times in the preoperative diagnosis of abdominal aortic aneurysms.

[Imaging of the hip joint hyaline cartilage with MR tomography using a gradient echo sequence with fat-water phase coherence]. / Darstellung des hyalinen Hüftgelenkknorpels mit der MR-Tomographie mittels einer Gradientenecho-Sequenz mit Fett-Wasser-Phasenkohärenz.

We have been able to display the hyaline hip joint cartilage clearly and with high signal strength in the magnetic resonance image with a gradient echo sequence with 2 different fresh hip specimens from corpses and with 10 healthy test subjects (5 m, 5 f). The chemical shift artifact at the bone-cartilage boundary could be clearly reduced by optimizing the geometrical scanning parameters. A comparison between the cartilage thickness at the head of the femur measured on the anatomical specimen with the thickness measured in the magnetic resonance tomogram showed a good correlation on suitable selection of the read-out gradient. The hyaline cartilage at the head of the femur could be differentiated from the acetabular cartilage in the region of the loading zone by magnetic resonance tomography in all 10 test subjects.

[A rare manifestation of Echinococcus cysticus in CT and magnetic resonance tomography]. / Seltene Manifestation des Echinococcus cysticus im CT und KST.

A case of primary spinal echinococcus with bone destruction is presented and the findings in CT and MR imaging are discussed. Although CT and MRI are complementary studies for the diagnosis of the spinal echinococcosis, MRI is the study of choice for prolonged follow-up of complicated cases.

[Arterial angio-CT and magnetic resonance tomography of Klatskin tumors]. / Arterielles Angio-CT und KST bei Klatskin-Tumoren.

The knowledge of the exact spreading and location of a malignant bile duct tumor and the exclusion of differential diagnoses are the prior conditions for the development of an optimal therapy concept. All usual methods such as ERCP, PTC, ultrasound, CT and angiography have weak points in the diagnosis of Klatskin tumors. A new aspect for the solution of this problem is the ability to visualize these tumors by arterial angio-CT and MR.

[Diagnosis of hernia using peritoneography]. / Herniendiagnostik durch Peritoneographie.

Peritoneography was performed in 1200 patients with ill-defined complaints concerning the abdominal wall, the groin or the pelvic floor. The purpose was to exclude or demonstrate the presence of a hernia. Amongst 750 patients, abnormalities were found in 53.5%. The examination was also carried out post-operatively in order to demonstrate possible recurrences which were not clinically obvious. Amongst 450 patients, a recurrence or a contra lateral hernia was demonstrated in 44%. These results show that a recurrence can only be demonstrated or excluded with certainty by means of peritoneography. The radiological examination is technically straightforward, can be carried out in a few minutes on an out patient basis and is simple for the patient.

[Primary carcinoid of the choledochus]. / Primäres Karzinoid des Ductus Choledochus.

The differential diagnosis of obstructive disease processes of the common bile duct can be very difficult even when sonography, endoscopic retrograde cholangiopancreatography (ERCP) and angiography are applied. In most cases, morphological changes are due to stones or carcinoma. We report on a case of a carcinoid tumor located in the intrapancreatic part of the common bile duct. Exact localization, delineation and demonstration of the local extension of such a tumor requires at least ERCP and angiography, as these are the most efficient imaging techniques for these purposes.

[The segmental form of adenomyomatosis of the gallbladder in the roentgen image and sonogram]. / Die segmentale Form der Adenomyomatose der Gallenblase im Röntgenbild und Sonogramm.

Case report of a 58-year-old patient, whose sonogram showed a segmental narrowing and thickening of the gallbladder wall. It was possible only by means of an intravenous cholecystography revealing the Rokitansy-Aschoff-sinus, to make the diagnosis of segmental adenomyomatosis. The criteria for the diagnosis of adenomyomatosis by sonogram as compared to x-ray are described.

[Arthrographic diagnosis of rupture of the anterior syndesmosis of the upper ankle joint]. / Die arthrographische Diagnostik der vorderen Syndesmosenruptur am oberen Sprunggelenk. Indikation, Technik und Ergebnisse anhand von 114 Fällen.

We describe 114 cases based on 2020 arthrographies of the ankle joint for diagnosing fresh tears of the tibio-fibula syndesmosis without bone lesions. Comparison of the arthrographical diagnosis with the intra-operative diagnosis showed good agreement. Diagnosis of the isolated tear of the tibio-fibular syndesmosis revealed a sensitivity of 90% and a specificity of 67%. The technical procedure and the isolated tear of the tibiofibular syndesmosis in combination with other capsuleligament lesions are presented, using typical x-ray images as examples.