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Biomedical subjects

U Mödder

Publications and source records attributed to U Mödder.

At least 73 records · Page 4Linked to original sources
PubMed2001

Assessment of radiocontrast media induced renal vasoconstriction by color coded duplex sonography.

INTRODUCTION: Changes in renal hemodynamics are suspected to be one of the major pathogenetic correlates in radiocontrast media-induced nephrotoxicity. We investigated whether color-coded duplex sonography is an appropriate method to document changes in intrarenal vascular resistance, after intravenous injection of the low-osmolar contrast material lopamidol. METHODS: Intrarenal arterial doppler wave forms were analyzed every minute after intravenous injection of 100 mL lopamidol in 10 patients during a voiding cystourogram-procedure. The Resistive Index (RI) of each flow curve, reflecting intrarenal flow resistance, was calculated and compared to the mean of four RI measurements taken before contrast media application. RESULTS: One minute after injection of Iopamidol the RI remained unchanged compared to the baseline standard of 0.70. In measurements obtained 2, 3, 4, and 5 minutes after lopamidol injection a statistically significant rise was seen: (minute 2: 0.74, p < 0.001/minute 3: 0.75, p = 0.001/minute 4: 0.72, p =0.018/minute 5: 0.74, p = 0.031). During the further course, the resistive indices decreased progressively and showed no significant difference in comparison with the baseline standard value. CONCLUSION: Color coded duplex sonography is a simple method to detect changes in renal flow resistance after application of radiocontrast media. Based on our results, we believe that the analysis of intrarenal arterial doppler flow profiles constitutes an ideal method to investigate pathophysiologic mechanisms of radiocontrast media-induced nephrotoxicity, as well as pharmacological concepts in nephroprotectivity.

Contrast Media↗
PubMed2001

HRCT findings of amiodarone pulmonary toxicity: clinical and radiologic regression.

Amiodarone is an antiarrhythmic drug that can cause interstitial pneumonitis leading to pulmonary fibrosis. A 62-year-old man suffering from atrial fibrillation and recurrent dyspnea was treated with amiodarone. After 15 months of treatment, HRCT revealed bilateral interstitial and alveolar opacifications with high-attenuating pleural-parenchymal consolidations, suggesting amiodarone induced pneumonitis. Three months after cessation of amiodarone treatment, HRCT shows complete regression of pneumonitis. Amiodarone pneumonitis can be misinterpreted and mistreated in patients with further underlying diseases. The present case report demonstrates the diagnostic value of HRCT in the diagnosis of interstitial pneumonitis.

Amiodarone↗
PubMed2001

MR imaging of bone marrow in glycogen storage disease type IB in children and young adults.

OBJECTIVE: Patients with glycogen storage disease type IB have neutropenia and neutrophil dysfunction that predispose them to frequent infections, for which they are given granulocyte colony--stimulating factor. Because neutropenia is a consequence of defects in myeloid maturation, the bone marrow aspirations show hypercellularity due to myeloid hyperplasia. This study evaluated MR imaging of bone marrow in glycogen storage disease type IB with and without granulocyte colony-stimulating factor. CONCLUSION: As confirmed by the histologic results in bone marrow aspirations, abnormal findings on MR images of bone marrow in patients with glycogen storage disease type IB indicate an increased myelopoietic activity, which is augmented by treatment with granulocyte colony-stimulating factor.

Adolescent↗
PubMed2000

[Innovative course concept for small group teaching in clinical methods. Results of a longitudinal, 2-cohort study in the setting of the medical didactic pilot project in Dusseldorf].

BACKGROUND AND OBJECTIVE: Medical students in Germany often criticize the anonymous and not practice-orientated way they are taught. It was the aim of this study to develop, try out and evaluate cost-effectiveness of practice-oriented interdisciplinary teaching in small groups. PATIENTS AND METHODS: The study was based on ca. 300 medical students/year, a practicable number in relation the average annual total intake by German medical schools. Between 1995 and 1998, 300 medical students annually, chosen by lot, were offered voluntary additional teaching of imaging methods (computed tomography, endoscopy and sonography), from a total of 2485 students (1276 females, 1209 males; mean age 25.8 years), the reminder serving as controls. After lecture-demonstration to all, the selected small groups were separately taught. They performed sonography on each other in small cohorts of 5 or they practised endoscopies on phantom models under supervision of a student tutor. In addition, lecturers circulated among the groups to answer additional questions and provide further help. All participants evaluated the course concept and the instructors on a questionnaire provided by the interdisciplinary centre for tertiary education. The effects of teaching on the participants were tested by a practical test in the form of an objective structured clinical examination (OSCE). RESULTS: Ca. 80% of course participants reached the intended aim and passed the OSCE examination. They gave the instructions in the pilot project highest marks, in all its criteria nearly one mark higher than those of other evaluated teaching sessions. Pre-clinical students judged the programme even more favourably than those in their clinical years. The additional cost incurred was moderately low at ca. DM 67 per year per student. CONCLUSION: Modern practice-oriented small group teaching will provide high quality results even with large numbers of students. The concept has already been taken over by other medical faculties.

Adult↗
PubMed2000

[Arthropathy in beta-thalassemia minor].

CASE REPORT: A 25-year-old Turkish patient presented with a "swelling" of the ankles which now persisted for 5 years. He had previously been diagnosed as having HLA-B27 negative spondylarthropathy with peripheral joint involvement. The symptoms failed to respond to different therapies. Serological markers and radiological procedures revealed beta-thalassemia minor. DISCUSSION: Symptoms, diagnostic procedures and differential diagnostic options are discussed.

Adult↗
PubMed2000

[Determining left and right ventricular volume ejection fractions (VEF) with MRI at 1.0 T. Comparison of manual and semi-automated endocardium detection].

PURPOSE: To evaluate method- and user effects as well as the required time in the determination of left- and right ventricular ejection fractions in comparing manual and semiautomatic border detection of the endocardium. METHODS: In 22 patients with varying cardiac diseases endocardial borders were detected either manually or semi-automatically (seeded ROI) and subsequently the right and left ventricular volume ejection fractions were computer-calculated. Two investigators defined the endocardial borders for both ventricles using both methods. For statistical analysis two-factorial analyses of variance were performed for the four variables: VEF right ventricle, VEF left ventricle, required time right ventricle, required time left ventricle (SAS, Anova). RESULTS: There was no user or method effect detectable for both ventricles. The required time for both ventricles also did not reveal a user effect, but there was a dramatic method effect concerning a reduction of the required time for analysis for both ventricles > 50%. CONCLUSIONS: The semiautomatic mode for detecting the endocardial borders in determining right and left ventricular ejection fractions did not demonstrate results differing from the results of the manual method, but is significantly superior concerning the time required for analysing ejection fractions of both ventricles with a reduction of over 50%. This might significantly reduce the expenditure for personnel.

Adult↗
PubMed2000

Type I gaucher disease: extraosseous extension of skeletal disease.

OBJECTIVE: To investigate the frequency and morphology of extraosseous extension in patients with Gaucher disease type I. DESIGN AND PATIENTS: MRI examinations of the lower extremities were analyzed in 70 patients with Gaucher disease type I. Additionally, the thoracic spine and the midface were investigated on MRI in two patients. RESULTS: Four cases are presented in which patients with Gaucher disease type I and severe skeletal involvement developed destruction or protrusion of the cortex with extraosseous extension into soft tissues. In one patient, Gaucher cell deposits destroyed the cortex of the mandible and extended into the masseter muscle. In the second patient, multiple paravertebral masses with localized destruction of the cortex were apparent in the thoracic spine. In the third and fourth patient, cortical destruction with extraosseous tissue extending into soft tissues was seen in the lower limbs. CONCLUSIONS: Extraosseous extension is a rare manifestation of Gaucher bone disease. While an increased risk of cancer, especially hematopoietic in origin, is known in patients with Gaucher disease, these extraosseous benign manifestations that may mimic malignant processes should be considered in the differential diagnosis of extraosseous extension into soft tissues. A narrow neck of tissue was apparent in all cases connecting bone and extraosseous extensions.

Adult↗
PubMed2000

Extraosseous manifestation of Gaucher's disease type I: MR and histological appearance.

Gaucher's disease type I is the most prevalent lysosomal storage disorder caused by an autosomal-recessive inherited deficiency of glucocerebrosidase activity with secondary accumulation of glucocerebrosides within the lysosomes of macrophages. The storage disorder produces a multisystem disease characterized by progressive visceral enlargement and gradual replacement of bone marrow with lipid-laden macrophages. Skeletal disease is a major source of disability in Gaucher's disease. Extraosseous extension of Gaucher cells is an extremely rare manifestation of skeletal Gaucher's disease. This is a report on the MRI and histopathological findings of an extraosseous Gaucher-cell extension into the midface in a patient with Gaucher's disease.

Biopsy↗
PubMed2000

Right and left ventricular volume measurements in an animal heart model in vitro: first experiences with cardiac MRI at 1.0 T.

The aim of this study was to determine the accuracy in quantifying right and left ventricular volumes using a 1.0-T system and commercially available, standard equipment. For exact comparison of MRI measurements and real volumes we used an animal heart model ex vivo. Eight pig hearts were explanted and prepared by removal of the atria. Aorta and pulmonary truncus were cannulated. Definable volumes were injected into the ventricles. Magnetic resonance imaging was performed at 1.0 T (Gyroscan T10 NT, Philips, Eindhoven, The Netherlands); sequence: fast field echo-echo planar (multishot EPI); body coil; MR software: Cardiac Application Package (Philips). Statistical analysis correlated the real volumes and MR measurements separately for both ventricles and two investigators (SAS, ANOVA). For both ventricles and both investigators the correlation between real volumes and MR measurements was greater than 0.99. There was no significant systematic false estimation for both ventricles. Magnetic resonance imaging at 1.0 T using standard hardware and software equipment enables the quantification of right and left ventricular volumes with high approximation to the real volumes in vitro. There is a clear restriction in translating these data into a clinical application because under experimental conditions no motion-induced artifacts existed.

Animals↗
PubMed2000

[MRI of aseptic osteonecrosis in children and adolescents with acute lymphoblastic leukemia].

PURPOSE: To evaluate the incidence, localisation, and course of symptomatic aseptic osteonecrosis (AON) in children undergoing treatment for acute lymphoblastic leukemia (ALL). METHODS: 72 MRI examinations obtained from 26 children with bone pain selected from a group of 121 children with ALL were evaluated retrospectively. The area of the AON was determined by computer assisted planimetry. Follow-up examinations after 2-5 years were considered. RESULTS: 10/121 (8.3%) of the children had symptomatic AON, the number of lesions varied between 1 and 24 per child. 62/66 lesions were localized within the lower extremities. 58% of the AON were positioned in the epiphysis and 42% in the meta- and diaphysis. The mean area of AON was 7.6 cm2 with a range of 0.5 to 50 cm2. Follow-up examinations revealed a regression in 19 AON, no change in 43 and a progression in 4 lesions. AON within the epiphysis with joint involvement or lesions greater than 9 cm2 more frequently showed a progression of AON with final joint destruction. An elevated risk for AON was seen in children older than 10 years and in children with intensified chemotherapy due to high-risk ALL. CONCLUSION: AON is a common complication in ALL-children under chemotherapy. Most frequently, the course is benign but large AON with joint involvement have an elevated risk for progression of AON with final joint destruction.

Adolescent↗
PubMed2000

[Ganglioneuromas in childhood: CT and MRI characteristics].

PURPOSE: The aim of this study was to demonstrate the typical appearance of ganglioneuromas in computer-assisted tomography (CT), and magnetic resonance imaging (MRI). MATERIAL AND METHODS: Retrospective analysis of diagnostic imaging (9 CT, 6 MRI) in 9 children aged 3 to 15 years with the histological diagnosis of ganglioneuroma. RESULTS: The tomographies showed large (max. 13.4 cm in diameter) round or oval tumors with sharp delineation. The sites of the tumors were the retroperitoneum (5), the mediastinum (3), and the adrenal gland (1). Intraspinal tumor involvement occurred in 4 cases. On comparing CT with MRI, MRI was more accurate in defining the intraspinal involvement. The ganglioneuromas were of hypodense appearance in the native CT scan and showed moderate enhancement upon administration of contrast media. In five patients tumor calcifications with a disseminated sprinkled pattern were seen in CT. In MRI T1-weighted scans the tumors were homogeneous and hypointense, after gadolinium application a marked enhancement was evident. In T2-weighted scans the tumors were hyperintense. CONCLUSION: At the time of diagnosis ganglioneuromas are generally large tumors which can be well detected by CT and MRI. Information towards the diagnosis is given by the appearance of the ganglioneuromas in CT and MRI. However, MRI is the modality of choice due to its superiority in documenting intraspinal tumor expansion.

Adolescent↗
PubMed2000

MRI evaluation of aseptic osteonecrosis in children over the course of hyperbaric oxygen therapy.

PURPOSE: The study aimed at MRI evaluation of aseptic osteonecrosis (AON) in children over the course of hyperbaric oxygen (HBO) therapy. MATERIAL AND METHODS: Retrospective analysis of 72 MRI studies in 20 children presenting with AON during chemotherapy. Two groups were differentiated: Gr. I (n = 8) was treated exclusively with relief of weightbearing structures, Gr. II (n = 12) was additionally treated with HBO therapy. The MRI examinations were evaluated by a point-score system (1-6 points) by two radiologists. RESULTS: Gr. II initially showed more severe findings (average score: 3.4) in comparison to Gr. I (average score: 2.65). During the follow-up time period the average scores rose to 3.2 score-points in Gr. I and 4.1 points in Gr. II. No statistically significant difference was evident between the two groups in the course of AON. CONCLUSION: The majority of chemotherapy associated AON which initially present with advanced findings show a progression in MRI over their further course. HBO therapy in addition to the relief of affected weightbearing structures statistically shows no significant improvement in MRI morphology during the course of the treatment.

Antineoplastic Agents↗
PubMed2000

Effect of acute intravenous ace-inhibition on the intrarenal doppler flow characteristics in hypertensive patients with and without unilateral renal artery stenosis.

Assessment of intrarenal doppler signals is of particular importance in screening for renal artery stenosis. We studied the effect of acute ACE-inhibition (1,25 mg enalaprilate i.v.) on intrarenal resistive indices in 10 hypertensive patients with unilateral renal artery stenosis versus 10 patients with essential hypertension. Any changes limited to poststenotic vessels could possibly improve the diagnostic value of duplex sonography. After ACE-inhibition a significant fall of the intrarenal Resistive Index occurred in both patient groups. In cases of unilateral renal artery stenosis we saw a tendency to an increased side difference of the Resistive Index due to a greater fall on the poststenotic side. Therefore a clear advantage of duplex scanning after acute ACE-inhibition due to a limited effect of enalaprilate on poststenotic vessels was not found. The results suggest that the vascular resistance and not only the degree of renal artery stenosis is of significance for the characteristics of the doppler signal.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Prostaglandin E1: a new agent for the prevention of renal dysfunction in high risk patients caused by radiocontrast media? PGE1 Study Group.

BACKGROUND: Acute renal failure following the administration of radiocontrast media (RCM) is a complication found especially in patients with impaired renal function. Within the limits of a pilot study, the objective was to (a) show the effectiveness and compatibility of prostaglandin E(1) (PGE(1)=Alprostadil) in preventing acute renal failure in patients with elevated levels of serum creatinine and (b) to identify the most appropriate PGE(1)-dose. METHODS: 130 patients with renal impairment (serum creatinine >/=1.5 mg/dl) were included in the study prior to intravascular RCM injection. The patients received one of three different doses of PGE(1) (10, 20, or 40 ng/kg bodyweight/min) or placebo (physiologic sodium chloride solution) intravenously over a time period of 6 h (beginning 1 h prior to RCM application). Serum creatinine was measured 12, 24, and 48 h post RCM-application and creatinine clearance was determined with two 12 h collection periods, as well as one 24 h collection within 48 h post RCM administration. Adverse events during PGE(1) administration were recorded. RESULTS: In the placebo group, the mean elevation of serum creatinine was markedly higher (0.72 mg/dl) 48 h after RCM administration compared with the three PGE(1) groups (0.3 mg/dl in the 10 ng/kg/min group, 0. 12 mg in the 20 ng/kg/min group, and 0.29 mg/dl in the 40 ng/kg/min group). No clinically relevant changes were seen regarding the creatinine clearance in the four groups examined. CONCLUSIONS: Results from this pilot-study suggest that intravenous PGE(1) may be used efficaciously and safely to prevent RCM-induced renal dysfunction in patients with pre-existing impaired renal function.

Acute Kidney Injury↗
PubMed2000

Post-transplant distal-limb bone-marrow oedema: MR imaging and therapeutic considerations.

BACKGROUND: In recent years a previously unrecognized pain syndrome of the distal lower limbs after organ transplantation has been noted. A relationship to cyclosporin A was suspected, but no clear aetiology and pathogenesis have been established. METHODS: During the last 30 months we diagnosed the pain syndrome in 10 patients after renal transplantation. We prospectively followed and evaluated the patients during their clinical courses and through pathological laboratory findings and magnetic resonance imaging (MRI). RESULTS: In all patients symptoms developed within 6 months of transplantation after otherwise uncomplicated clinical courses without graft rejection episodes. Impressive bone-marrow oedema on MRI as well as elevated serum alkaline phosphatase was seen in all patients, and often exceeded the duration of clinical symptoms. All patients were instructed to avoid stress to the extremities through immobility, and steroid doses were tapered down. Within 14 weeks, eight patients were free of symptoms. Two patients have not experienced remission after 3 and 4 months respectively. None of the patients developed signs of osteonecrosis. CONCLUSION: Post-transplant distal limb bone-marrow oedema presents with distinct clinical findings and signs of bone-marrow oedema on MRI. Proven standard treatment does not exist. In our experience the elevation of the extremities, the strict avoidance of physical strain, and a stepwise withdrawal of steroids facilitates progressive disappearance of symptoms. Long-term damage to the affected ostial structures has not been seen, in contrast to avascular femoral-head necrosis.

Adult↗
PubMed2000

Diffusion- and perfusion-weighted MRI: influence of severe carotid artery stenosis on the DWI/PWI mismatch in acute stroke.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) have been used increasingly in recent years to evaluate acute stroke in the emergency setting. In the present study, we compared DWI and PWI findings in acute stroke patients with and without severe extracranial internal carotid artery (ICA) disease. METHODS: Twenty-seven patients with nonlacunar ischemic stroke were selected for this analysis. DWI, PWI, and conventional MRI were performed in all patients within 24 hours of symptom onset and after 1 week. To exclude patients with partial or complete reperfusion, we included only patients with a PWI deficit larger than the DWI lesion. Severe ICA disease (>70% stenosis) was present unilaterally in 9 and bilaterally in 2 patients. Acute DWI lesion volume, the size of the acute PWI/DWI mismatch, and final infarct size (on T2-weighted images) were determined. RESULTS: The PWI/DWI mismatch was significantly larger in patients with severe ICA disease than in patients without extracranial carotid stenosis, both when time-to-peak and mean transit time maps (P<0.01) were used to calculate the mismatch. Quantitative analysis of the time-to-peak delay in the mismatch indicated that a relatively smaller fraction of the total mismatch was critically ischemic in patients with carotid stenosis than in those without. Average lesion volume increased less in the stenosis group (P=0.14), despite the larger PWI/DWI mismatch, and final infarct size was smaller in the stenosis group (P<0.05). In the 2 patients with bilateral ICA disease, variable hemodynamic involvement of the contralateral hemisphere was found in addition to the ipsilateral PWI deficit. CONCLUSIONS: In most acute stroke patients with severe ICA stenosis, a considerably smaller fraction of the total PWI/DWI mismatch is at risk than in patients without carotid disease.

Acute Disease↗
PubMed2000

CT of the head by use of reduced current and kilovoltage: relationship between image quality and dose reduction.

BACKGROUND AND PURPOSE: CT is a frequent examination that is performed using ionizing radiation. We sought to assess image-quality changes on CT scans of the head when the radiation dose is reduced by changing tube current and kilovoltage. METHODS: A formalin-fixed cadaver was examined in conventional and helical mode by use of two CT-scanners. Surface dose was measured with standard scanning parameters, and after reduction of tube current and kilovoltage. Five experienced examiners independently evaluated subjective image quality. RESULTS: In the conventional mode, the highest surface dose was 83.2 mGy (scanner 1: helical mode, 55.6 mGy), and 66.0 mGy (scanner 2: helical mode, 55.9 mGy). By changing kVp and mAs, a dose reduction of up to 75% (scanner 1), and 60% (scanner 2) was achieved. No observable differences in image quality between scans obtained with doses from 100% to 60% of standard settings were noted. Ten of 20 images obtained with the highest dose and 13 of 20 images obtained with lowest dose (19-29.4 mGy) were reliably identified by subjective quality assessment. Scans produced with a surface dose of less than 30 mGy were judged uninterpretable. CONCLUSION: Standard parameters used in cranial CT are oriented toward best image quality. A dose reduction up to 40% may be possible without loss of diagnostic image quality.

Cadaver↗