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Biomedical subjects

A Oberstein

Publications and source records attributed to A Oberstein.

At least 19 recordsLinked to original sources
PubMed2000

Age-related reference ranges for fetal foot length.

AIM: The aim of this study was to establish age-dependent reference ranges for fetal foot length with gestation as well as for the femur/foot length ratio, based on a mathematical growth model. METHOD: In a prospective cross-sectional study of 610 pregnancies with sonographically confirmed gestational age (< 12 weeks' gestation), fetal biometry was performed in addition to measurements of fetal foot length between 12 and 42 completed weeks of gestation. Reference ranges for the fetal foot and for the femur/foot length ratio were constructed with an overall coverage of 90% of the measured data, using a previously established method of determining reference bands for growth parameters. RESULTS: Foot length was noted to level off slightly up to 24 weeks of gestation and it continued in a nearly linear fashion thereafter. The femur/foot length ratio was associated with a mean value of approximately 1 up to 24 weeks of gestation, falling to below 1 after this time point to a value of 0.85 at 41 weeks' gestation. The comparison of the reference ranges established in this study with anatomic and sonographic reference ranges for the fetal foot demonstrates good conformity with the anatomic reference range published by Streeter as early as 1920, and a large degree of conformity with the sonographic reference range developed by Mercer and co-workers. CONCLUSION: The proposed statistical approach offers reliable reference ranges for the fetal foot and for the femur/foot-ratio as well.

Cross-Sectional Studies↗
PubMed1998

Preoperative estimation of screw fixation strength in vertebral bodies.

STUDY DESIGN: Bone mineral density and bone cross-sectional area of human cadaveric vertebral bodies were investigated radiologically and histologically, respectively. After ventral instrumentation with ventral derotation spondylodesis screws, axial pullout force was measured and compared with radiologic and histologic data. OBJECTIVES: To elucidate how well ventral derotation spondylodesis screw fixation strength can be estimated before surgery by specified applications of dual-energy x-ray absorptiometry, quantitative computed tomography, T2*-relaxation time in magnetic resonance imaging, and histomorphometry. SUMMARY OF BACKGROUND DATA: It is postulated that bone quality plays a crucial role in initial strength of the instrumented spine. Bone quality is even more important in anterior fixation because of the prevalence of spongy bone in the vertebral body. METHODS: Bone mineral density of human cadaveric lumbar-vertebral bodies was assessed by dual-energy x-ray absorptiometry and quantitative computed tomography (cancellous and cortical bone separately). Cancellous bone was also characterized by T2*-relaxation time, measured by magnetic resonance imaging and histomorphometric study. Vertebral bodies were instrumented ventrally with VDS screws, and screw axial pullout force was measured and correlated with each of the nonmechanical measures. Patients with manifest osteoporosis, osteomalacia and tumors were excluded. For statistical analysis, the Mann-Whitney rank sum test was used with a significance value of P < 0.05. RESULTS: The highest correlation with pullout force was for density of cancellous bone determined by quantitative computed tomography (r = 0.72; P < 0.001), immediately followed that determined by dual-energy x-ray absorptiometry (r = 0.70; P < 0.001). Results of measurement of T2*-relaxation time and those of histomorphometric study correlated moderately (r = 0.55; r = 0.50), whereas cortical bone density determined by quantitative computed tomography showed negligible correlation (r = 0.2). CONCLUSIONS: The absorptiometric techniques, quantitative computed tomographic scan of cancellous bone and dual-energy x-ray absorptiometric study, provide more accurate readings for preoperative estimation of initial VDS screw fixation strength than do the other methods studied.

Absorptiometry, Photon↗
PubMed1997

[Comparison of radiological procedures in preoperative assessment of anchorage strength of spinal implants].

PURPOSE: To compare three techniques with regards to their ability to estimate pull out strength of spinal fusion hardware. MATERIAL AND METHODS: VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pull out force measurement. Bone quality was assessed by Dual X-ray Absorptiometry (DXA). Quantitative Computed Tomography (QCT) and T2*-relaxation time. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS: Highest correlation was found for cancellous bone density measured by QCT (r = 0.72; p < 0.001). Immediately followed by DXA (r = 0.70; p < 0.001), which involves all bone components. Inverted T2*-relaxation time (r = 0.55; p < 0.001) and cortical bone density (QCT) correlated just slightly with pull-out force strength. CONCLUSIONS: Absorptiometrical techniques like QCT and DXA are most appropriate to estimate VDS-screw fixation strength preoperatively.

Absorptiometry, Photon↗
PubMed1997

Non invasive evaluation of the inflammatory activity in sarcoidosis with high-resolution computed tomography.

PURPOSE: The value of high resolution computed tomography (HR-CT) in the recognition of pathologic changes of the lung parenchyma, especially in the diagnosis of sarcoidosis, is well established. The importance of these findings in regard to the inflammatory activity is not sufficiently documented, also because a direct histologic correlation is seldom possible. METHOD: In a prospective study twenty-one patients with suspected or known sarcoidosis were evaluated. The diagnostic work up comprised the clinical examination, lung function tests, the radiological evaluation, including GH-CT, and bronchoscopy for bronchoalveolar lavage (BAL) and transbronchial biopsy. RESULTS: The comparison of the HR-CT findings, like pathologic appearance of the bronchovascular bundle and intraparenchymal nodules, with serologic and BAL-parameters yielded high correlation coefficients with the total cell count in BAL and sIL-2R, and moderate correlations with the lavage lymphocyte count and the activity markers, like T4/T8 ratio, IL-2R and HLA-DR expression. CONCLUSION: As a non invasive method, HR-CT depicts pathologic findings of the lung parenchyma which are associated with the inflammatory activity of sarcoidosis.

Adult↗
PubMed1996

[Triphasic spiral CT in the diagnosis of liver diseases: comparison with CT arteriography and CT arterio-portography].

PURPOSE: Assessment of the diagnostic efficacy of triphasic spiral-CT scanning (TPS-CT) for liver disease evaluation. CT arteriography (CTA) and CT arterio-portography (CTAP) were used as reference, methods which together have the highest sensitivity for detecting tumours and the perfusion conditions of the liver. MATERIAL AND METHODS: 50 TPS-CT and CTA/CTPA were performed in 49 patients. After an initial examination without enhancement the first scan was initiated 15-25s after the peripheral bolus injection of contrast medium, the second after an interscan delay of 20-25s. By this means the liver was imaged in different phases of perfusion. In the course of the CTA/CTPA-exam the imaging was carried out after selective, intraarterial application of contrast agent. RESULTS: The differentiation of the perfusion phases succeeded in 90% of the patients. When compared with standard CT, which images only the portal venous phase, the new technique, which additionally shows the arterial perfusion, accomplished an increase in sensitivity for hypervascular lesions (51% vs. 60%). Yet in comparison with CTA/CTPA fewer lesions could be detected (87 vs. 138). Furthermore, by documenting the contrast agent kinetics, characterisation of the lesion was also facilitated. CONCLUSION: DPS-CT is a valuable additional tool for imaging the liver, even if the information yield is less when compared to CTA/CTPA.

Adult↗
PubMed1994

[Isolated fracture of the trochlea humeri following direct elbow trauma].

Isolated fractures of the Trochlea humeri are only rarely seen because in case of indirect trauma this portion of the elbow is only partially exposed to transmitted forces and in case of direct injury adjacent elements are also involved. On the lateral films a half-moon shaped fragment in front of the Humerus together with joint effusion are indicative of this type of fracture. Depending on the grade of dislocation of the fragment, which has to be shown radiologically, conservative or operative management are chosen.

Athletic Injuries↗
PubMed1993

Preoperative staging of breast cancer by palpation, mammography and high-resolution ultrasound.

In breast cancer preoperative determination of the tumor size is important for planning breast-conserving operations. In 100 patients with breast cancer, the preoperative tumor size was measured using clinical, mammographic and sonographic examinations and correlated with the results of a subsequent histological examination. Using a high-resolution real-time system, 98 tumors were visible. It was possible to detect not only early tumors under 1 cm in diameter, but also intraductal tumor components. This contributed greatly to the accuracy of the diagnosis. The sonographic measurement of tumor size demonstrated a correlation coefficient of 0.91 and was thus superior to mammography (0.79) and palpation (0.77). Measurement of the total tumor spread, including 39 multicentric lesions, showed an overestimation of 5% for the mammographic measurements and an overestimation of 4% for the sonographic measurements. Tumor extension was underestimated in 33% of the mammograms but in only 3% using ultrasound examination. The results, along with those of other studies, highlight the role of sonography in the diagnosis of breast cancer.

Journal Article↗
PubMed1993

[Jejunogastric invagination: plain radiologic, sonographic and computed tomographic findings].

Jejunogastric intussusception is a rare complication after gastric surgery and when its diagnosis is delayed a high mortality rate can be expected. This paper reports on the characteristic findings of this entity at ultrasound and CT examination. Both diagnostic procedures have a high sensitivity. Sonography is the method of first choice because the diagnosis can be made with a high grade of certainty. CT allows the differentiation of the distinct stages of the disease and the views given by CT are often more easily accepted by the surgeons.

Adult↗
PubMed1992

[Gas-forming infections of the extremities].

A variety of cases of gas-forming infections has been collected and the radiological appearances due to the gas formation are described. In the context of the clinical situation the development of gas gangrene can be distinguished from other gas-forming infections which are mostly due to B. coli or cellulitis due to anaerobic streptococci. In addition to describing the pathology and clinical course, the possible forms of treatment are discussed.

Arm↗
PubMed1992

[The CT diagnosis of hemorrhages into the abdominal musculature resulting from therapeutic procedures on the coagulation system].

Eleven patients treated by anticoagulants or lytic therapy suffered bleeding into the abdominal muscles, resulting in neurological symptoms or those of an acute abdomen. By means of CT it was possible to demonstrate the bleeds and to clarify the differential diagnosis, thereby leading to correct treatment. The possibility of early diagnosis of haemorrhages makes CT a suitable and reliable method.

Abdomen, Acute↗
PubMed1991

[Whole-body MRT studies--the results of the "Multicenter study on the evaluation of magnetic resonance tomography"].

In a nation-wide multicentre study, the use of MRI was examined in its clinical context and in relation to other imaging methods and as a routine examination. It was found that examinations of the brain and spine were predominant. MRI is accurate for certain problems affecting the extremities, the pelvis and the liver. The findings also show that there are still technical limitations. A high degree of accuracy can only be obtained if there is adequate information concerning individual problems. Technical limitations include the frequent appearance of artifacts. In its present state, MRI can only supply additional information, concerning the trunk only, in certain situations. The study also outlines the development of MRI and the role of other conventional diagnostic procedures.

Evaluation Studies as Topic↗
PubMed1991

[The radiologic picture of pathomorphological changes in the intestinal wall in Crohn disease in relation to the course of the disease].

Crohn's disease has highly variable presentation in the x-ray examination depending on the stage of the gut wall inflammation. Our series showed that the lesions concern mainly the ileocecal region with involvement of the terminal ileum in 72.4% and of the cecum in 56.2% of the cases. In patients who required only conservative treatment mainly "cobble stone"-lesions, pseudopolyps and pseudodiverticuli could be demonstrated. Patients who needed surgical therapy showed in the first place stenosis, spicules and fistulae. Of all the studied patients 59% had to be assigned to surgery and of these 62% showed signs of relapse. The recurrence of disease occurred in 88% at the site of the anastomosis mainly in the first two years after operation. Differences in the frequency of relapse after the first or the second operation could not be seen.

Adolescent↗
PubMed1990

[NMR studies of the whole body--results of a multicenter study for evaluating nuclear magnetic resonance tomography].

Within the framework of a national multi-centre study the spectrum of application and the ranking of magnetic resonance tomography were investigated. Although scans of the brain and vertebral column still dominate the scene, it has become evident that whole body scanning via MR can be very accurate for certain indications. This is particularly true for examinations of gynaecological diseases (95%) and for lesions of the liver (97%). However, the number of problems in which MR can provide answers to diseases in the whole body range is still limited, and hence it would be most desirable to achieve further instrumental and methodical improvements.

Brain Diseases↗
PubMed1990

[Obstacles to the routine use of magnetic resonance imaging--results of a multicenter study for evaluating nuclear magnetic resonance tomography].

Within the framework of this study, the factors that impair the value of MR scans were also investigated and analysed. It was found that artifacts occurred in a large number of examinations that exercised a negative effect on the results. Artifacts are particularly seen in the thorax (54%) and upper abdomen (57%), but they have also been reported in 23% of the CNS examinations. The sources of such artifacts were mainly movements in the investigated layer, whereas other causes were negligible. In the 21,633 examined patients no undesirable effects caused by the examination were noted that would have impaired the patient or the course of the study. On an average, 88% of the examinations were performed with normal tolerance of the examination. In the remaining cases there was motor unrest or claustrophobia requiring special measures, thus hampering the course of the examination.

Diagnosis, Differential↗
PubMed1990

[Evaluating magnetic resonance tomography studies of the extremities--results of a multicenter study for evaluating nuclear magnetic resonance tomography].

MR examinations of the extremities occupy the first place in whole body examinations via MR. Highest accuracy quotas in this area with an average of 93.8% were obtained for tumours, trauma and necroses of the bones. These high accuracy quotas, however, were achieved only if sufficient preliminary information was available. Other statistically significant factors were found to be the field strength, the combined use of spin echo and fast imaging sequences and the use of the multislice technique.

Bone Neoplasms↗
PubMed1990

["Coral reef" arteriosclerosis: computed tomographic and angiographic findings].

Patients suffering from "coral reef arteriosclerosis" are presented, the lesions being visualised via CT and angiography. This disease is characterised by an almost complete occlusion of the median ventricular aorta due to extreme, irregularly structured calcareous masses in the vascular lumen. The review of the literature points to the possible aetiology and pathogenesis of this disease pattern.

Angiography, Digital Subtraction↗
PubMedDate not supplied

[Determination of bone quality before spinal instrumentation--value of different in vivo methods].

OBJECTIVE: The present investigation should elucidate which assessment technique for bone quality is most appropriate to estimate preoperatively fixation strength of instrumental spine fusions. METHODS: VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pullout force assessment. Bone quality was assessed by Dual Energy X-ray Absorptiometry (DEXA), Quantitative Computed Tomography (QCT), MRT and histomorphometry. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS: Highest correlation was found for cancellous bone density (QCT) (r = 0.72; p < 0.001) and DEXA (r = 0.70; p < 0.001). MRT, cortical bone density (QCT) and histomorphometry just slightly correlated with pullout force strength. CONCLUSIONS: Absorptiometrical techniques like QCT and DEXA are most appropriate to estimate VDS-screw fixation strength preoperatively.

Adult↗