Biomedical subjects

M Reiser

Publications and source records attributed to M Reiser.

At least 145 records · Page 8Linked to original sources

PubMed2001

[Screening lowers breast cancer mortality. Motivate your patients for mammography].

Breast cancer is the most common malignant disease in women under 70, and the most common cause of death in those under 50. Causal prophylaxis is unknown. Only early diagnosis prior to the onset of lymphogenic or hematogenic metastasization improves the prognosis. Since the early nineteen-sixties, large-scale studies have shown that screening mammography can reduce mortality. Furthermore, early diagnosis enables breast-conserving treatment in up to 70% of cases. Disadvantages of screening mammography currently under discussion are the radiation burden, the number of false-positive diagnoses prompting biopsy and incurring costs. In Germany, the cost of screening mammography in women with no relevant history or clinical symptoms is not borne by the state-affiliated health insurance carriers. Currently, ongoing pilot projects are investigating quality-controlled early diagnosis with mammography.

Adult↗

PubMed2001

Contrast-enhanced MR angiography in patients after kidney transplantation.

The aim of this study was to investigate the value of a contrast-enhanced 3D MR angiography in detecting postoperative vascular complications after kidney transplantation in comparison with digital subtraction angiography (DSA). Forty-one patients who underwent a kidney transplantation were examined with MR angiography and DSA. Contrast-enhanced MR angiography was performed as a dynamic measurement with one precontrast and three postcontrast measurements. Maximum intensity projection reconstructions were performed for all postcontrast data sets after DSA. The results were evaluated by two independent observers who were unaware of the DSA results. Twenty-three hemodynamically significant arterial stenoses were identified with DSA in the iliac arteries ( n=7), the renal allograft arteries ( n=12), and in their first branches ( n=4). For a patient-based analysis the sensitivity and specificity, respectively, for observer 1 were 100 and 97%, and for observer 2, 100 and 93%. Respective data were 100 and 100% after a consensus evaluation by two observers. Complications involving the renal veins were detected in 2 cases and perfusion defects of the kidney parenchyma were detected in 4 cases. Contrast-enhanced MR angiography is a reliable method in identifying postoperative arterial stenoses after kidney transplantation. In addition, dynamic MR angiography can be helpful in detecting venous complications and perfusion defects in kidney allografts.

Adult↗

PubMed2001

[Brain protective interstitial laser thermotherapy. Therapy of brain tumors without secondary damage].

The purpose of interstitial radiosurgery is to deliver a necrotizing dose of heat to an accurately defined focal area without damaging adjacent healthy brain tissue. To achieve this, heat at a temperature of 60-100 degrees C is applied via a laser fiber placed stereotactically in the center of the tumor. With the aid of thermosensitive magnetic resonance imaging (MRI), not only can the heat distribution within and around the tumor be measured during treatment, but also the extent of the lesion produced assessed. Interstitial laser thermotherapy (ILTT) performed under MRI monitoring, could become an important interdisciplinary minimally invasive treatment option for patients with brain tumors. Experimental data on the biological effects of interstitial laser therapy on normal brain tissue are not yet available, and only preliminary clinical studies investigating the effects of laser energy on brain tumors have so far been carried out. This overview presents a description of our own initial results, discusses the present state of our knowledge and current possibilities and limitations of this new treatment modality.

Brain↗

PubMed2001

Magnetic resonance imaging-based assessment of cartilage loss in severe osteoarthritis: accuracy, precision, and diagnostic value.

OBJECTIVE: To examine the in vivo accuracy and precision of magnetic resonance imaging (MRI)-based assessment of cartilage loss in patients with severe osteoarthritis (OA) of the knee. METHODS: High-resolution MRI images of the tibial cartilage were obtained in 8 patients prior to total knee arthroplasty, using a water-excitation gradient-echo MRI sequence (acquisition time 6 minutes 19 seconds; spatial resolution 1.2 x 0.31 x 0.31 mm3). The MRI measurements were repeated after joint repositioning. The precision of the cartilage volume and thickness computations was determined after 3-dimensional reconstruction. During surgery, the tibial plateaus were resected, and the MRI data were compared with water displacement of surgically retrieved cartilage. RESULTS: The standard deviation (coefficient of variation) of repeated tibial cartilage volume measurements was 56 mm3 (5.5%) medially and 59 mm3 (3.8%) laterally. The deviation from surgically removed tissue was -13%, on average, with a high linear correlation between both methods (r = 0.98). In patients with varus OA, the tissue loss was estimated to be 1,290 mm3 in the medial tibia and 1,150 mm3 in the lateral tibia, compared with the data in healthy volunteers. CONCLUSION: Noninvasive quantitative MRI-based analysis of cartilage morphometry in severe OA is accurate, precise, and displays high potential diagnostic value.

Aged↗

PubMed2001

Age-related changes in the morphology and deformational behavior of knee joint cartilage.

OBJECTIVE: Alterations of cartilage morphology and mechanical properties occur in osteoarthritis, but it is unclear whether similar changes also take place physiologically during aging, in the absence of disease. In this in vivo study, we tested the hypothesis that thinning of knee joint cartilage occurs with aging and that elderly subjects display a different amount of cartilage deformation than do young subjects. METHODS: We evaluated 30 asymptomatic subjects ages 50-78 years. Morphologic parameters for the knee cartilage (mean and maximum thickness, surface area) were computed from magnetic resonance imaging data. Results were compared with those in 95 young asymptomatic subjects ages 20-30 years. Deformation of the patellar cartilage was determined after the subjects performed 30 knee bends. RESULTS: There was a significant reduction of patellar cartilage thickness in elderly women (-12%; P < 0.05), but not in elderly men (-6%). Femoral cartilage was significantly thinner in both sexes (-21% in women, -13% in men; P < 0.01), whereas tibial cartilage thickness displayed only nonsignificant trends (-10% in women, -7% in men). Patellar cartilage deformation was -2.6% in elderly women and -2.2% in elderly men. These values were significantly lower (P < 0.05) than those in young subjects. CONCLUSION: We confirmed the hypothesis that knee cartilage becomes thinner during aging, in the absence of cartilage disease, but that the amount of reduction differs between sexes and between compartments of the knee joint. We show that under in vivo loading conditions, elderly subjects display a lower level of cartilage deformation than do healthy young subjects.

Adult↗

PubMed2001

MR lung imaging at 0.2 T with T1-weighted true FISP: native and oxygen-enhanced.

An inversion recovery true fast imaging with steady precession (FISP) pulse sequence was developed to carry out fast imaging of the lungs at 0.2 T. Using this sequence, oxygen-enhanced magnetic resonance (MR) lung imaging was performed on healthy volunteers. The lungs showed signal enhancement (11.7% +/- 3.8%) when breathing 100% oxygen. Using inversion recovery, true FISP at low field may prove promising for MR lung imaging.

Artifacts↗

PubMed2001

[Effect of muscle activity on the 3-dimensional movement pattern of the shoulder. Study with open MRI].

The objective of this study was to analyze the influence of shoulder muscle activity on the three-dimensional motion pattern of the shoulder girdle in the living. 14 healthy volunteers were investigated with an open MRI system at 60-120 degrees abduction--with and without activity of the shoulder abductors. The 3D motion pattern of the humerus, scapula, clavicle and M. supraspinatus were computed. Under muscle activity, the glenoid demonstrated a slightly reduced elevation at 60 degrees of abduction (20.5 degrees +/- 8.2 degrees vs. 23.1 degrees +/- 6.3 degrees; not significant), and at 120 degrees a significantly higher degree of rotation under muscle activity (43.3 degrees +/- 8.6 degrees vs. 36.1 degrees +/- 5.2 degrees; p < 0.01), whereas at 90 degrees no difference was observed. This caused a significant reduction of the scapulo-humeral rhythm at 120 degrees (2.6 vs. 1.5; p < 0.01), a significant increase of the supraspinatus angle (123.3 degrees +/- 6.7 degrees vs. 117.3 degrees +/- 6.5 degrees; p < 0.05) as well as a reduction of the supraspinato-humeral relationship (1.0 vs. 0.97). The study demonstrates that muscle activity leads to an alteration of shoulder girlde motion patterns at higher degrees of abduction, with increased rotation of the scapula, an altered spatial relationship between the supraspinatus and humerus.

Adult↗

PubMed2001

[Improvement in diagnosis of liver metastases with the multi-detector CT].

The introduction of multidetector computed tomography in clinical routine creates a new dimension of increased spatial and temporal resolution in CT scanning. On the basis of the very short acquisition time, the whole liver can now be scanned within one breathhold. Multidetector-CT allows the examination of the liver with nearly isotropic data sets. This is the prerequisite for the optimal assessment of very small liver lesions in all planes and excellent enhancement of liver lesions in defined organic perfusion phases. The speed of multidetector-CT can either be used to reduce the time to cover a given volume, or to use narrower beam collimation to increase the resolution of details along the z-axis and to reduce volume averaging. We report our clinical experiences in hepatic multidetector-CT examinations and optimized examination protocols in the assessment of hepatic metastases. Multidetector-CT and the use of interactive multiplanar reconstructions improve the detection and characterization of liver metastases. However, new problems in data management may arise from the large amount of data generated by multidetector-CT.

Colorectal Neoplasms↗

PubMed2001

[Radiofrequency ablation of liver metastases. Technique and initial results].

Primary and secondary malignant hepatic tumors are the most common tumors with a much more higher incidence of hepatic metastases. Chemotherapy and radiation therapy are in general ineffective. Therefore, surgical resection is considered the method of choice in the treatment of malignant hepatic lesions. Due to systemic disease, general medical or procedure-related reasons hindering surgery, only 25 to 45% of the patients with metastatic disease of the liver are suitable for a curative surgical therapy. In resectable lesions thermoablative methods can offer an alternative to the surgical therapy. The most experience exists in radiofrequency ablation techniques. Technique, indications, contraindications, and limitations of the radiofrequency ablation will be discussed together with a presentation of own cases and a review of the literature. In 37 patients the primary technical success rate of the ablation was 97.3% (72 of 74 lesions). In 4 cases a hematoma of the liver capsule occurred. One of these had to be treated interventionally. During the limited follow-up period of 9 months no local recurrency was seen, however 4 patients developed new hepatic metastases. Beside differences in practicability it is not yet clarified if there are differences in the therapeutic efficacy of the different thermoablation methods. Nevertheless, the results of the ablation therapy may parallel the results of the surgical resection. Interstitial thermotherapy can provide a valuable contribution to local tumor control. However, the final significance of the thermoablation techniques within oncological therapy regimens has to be evaluated in further multidisciplinary studies.

Adult↗

PubMed2001

[TIPS in patients with therapy refractory ascites and kidney dysfunction].

BACKGROUND: A transjugular intrahepatic portosystemic shunt (TIPS) is increasingly being used for treatment of patients with refractory ascites and renal failure. The aim of this study was to investigate the effects of TIPS in patients with refractory ascites and organic or functional renal impairment. METHODS: A TIPS was placed for refractory or intractable ascites in 10 consecutive patients with liver cirrhosis and impaired renal function (serum creatinine > 1.5 mg/100 ml). Four of them had organic kidney disorders. The other six patients had functional renal impairment due to the underlying liver disease. RESULTS: TIPS was effective in reducing ascites in 8 of 10 patients, including all patients with organic renal disease. Furthermore, after TIPS the renal function improved in all patients. Serum creatinine and serum urea levels decreased significantly from 1.8 to 1.5 mg/100 ml (p < 0.05) and from 107 to 78 mg/100 ml respectively. CONCLUSION: TIPS may be useful in patients with functional and in patients with organic renal disease, resulting in improvement of ascites and renal function.

Aged↗

PubMed2001

[Diagnostic imaging of the normal anatomy of the temporomandibular joint].

Computed tomography (CT) and magnetic resonance imaging (MRI) are well established imaging modalities to examine the TMJ. MRI is superior to CT in delineating the morphological architecture of the TMJ, not only in cases of normal anatomy, inflammation or tumors, but also if dysfunction of the TMJ is present. This review article presents anatomy as well as imaging strategies of the TMJ.

Humans↗

PubMed2001

[Diagnosis of aortic aneurysm].

The aim of the study was to analyze the use and indication of 3 imaging modalities (CT, DSA and MRI) for patients with suspicion of aortic aneurysm. During 18 months 383 patients with suspicion of aortic aneurysm were examined with CT (SCT/MSCT), 17 with digital subtraction angiography (DSA), and 15 with MRI. Diagnostic DSA was performed in 7 cases for planning endoluminal therapy, in 7 cases because of unclear findings in CT and in 4 cases because of dissection of the aorta. MRI was performed in 12 cases with previously performed CT and in 3 cases as the only imaging modality because of intolerance to iodinated contrast material. CT is a well established and in most cases sufficient method for the examination of patients with the suspicion of aortic aneurysm. CT is widely available, and provides good image quality and a high diagnostic accuracy. Additional examinations with DSA or MRI are necessary in less than 5% of the patients.

Aged↗

PubMed2001

[Reconstruction methods in postprocessing of CT- and MR-angiography of the aorta].

The aim of the study was to investigate the use of 2D and 3D reconstructions in examinations of the aorta with CT and MRI. Postprocessing of 5 data sets including 2D MPR reconstructions, 3D MIP reconstructions and 3D volume rendering reconstructions acquired with contrast enhanced CTA and 5 data sets acquired with contrast enhanced MRA were performed. The luminal diameter, the length of the aneurysm and the detection of dissection was assessed for the reconstructions and the source images. Aneurysms and dissections of the aorta were correctly identified on source images. 2D MPR reconstructions and source images allow for a clear and easy image analysis including cases with high signal intensity or density of surrounding tissue and complex anatomical structures. The diameter and length of pathological findings can be determined correctly wit 2D MPR reconstructions, even when the vessel orientation is not exactly inplane or throughplane in relation to the source images. MIP reconstructions are suitable for contrast enhanced MRA data sets with high C/N ratio and volume rendering reconstructions are suitable for contrast enhanced CTA data sets, where calcifications and bone have also high density. For 3D visualization of large volumes MIP reconstructions are the method of choice for MRA and volume rendering reconstructions for CTA, respectively. In addition, 2D MPR can be necessary to determine the diameter and length of pathological findings.

Adult↗

PubMed2001

MR imaging of the wrist in rheumatoid arthritis using gadobenate dimeglumine.

OBJECTIVE: To determine the dosage of gadobenate dimeglumine (Gd-BOPTA) necessary for MRI of rheumatoid arthritis of the wrist. DESIGN AND PATIENTS: Seven wrists inflamed with rheumatoid arthritis were imaged using a dedicated 0.2-T MR unit. Four cumulative dosages of 0.0125, 0.025, 0.05 and 0.1 mmol/kg body weight (BW) Gd-BOPTA were tested. Three-dimensional T1-weighted gradient-recalled echo sequences (GRE; TR: 100 ms, TE: 18 ms, flip angle 90 degrees , 4:55 min) were acquired prior to an intravenous injection and after each additional dosage of Gd-BOPTA. Relative enhancement, signal-difference-to-noise ratios (SDNRs) and the size of the inflamed tissue were quantified. Three radiologists independently evaluated the image quality, the size and the contrast of the enhancing tissue. RESULTS: The readers agreed on a dose of 0.05 mmol/kg BW as satisfactory for the evaluation of the size of the inflammatory tissue and for determination of bone involvement (kappa = 0.9, P < 0.001). Highly inflammatory pannus was depicted with adequate image contrast using 0.025 mmol/kg BW Gd-BOPTA. According to the SDNR and relative enhancement findings, a dose of 0.05 mmol/kg BW suffices for both off-center and centered regions of tissue inflammation (t-test, P < 0.05). CONCLUSION: Gadolinium-BOPTA is an alternative contrast agent for MRI of rheumatoid disease. This study shows that a dose of 0.05 mmol/kg BW suffices at low field strength.

Adult↗

PubMed2001

Gender differences in knee joint cartilage thickness, volume and articular surface areas: assessment with quantitative three-dimensional MR imaging.

OBJECTIVE: To compare the cartilage thickness, volume, and articular surface areas of the knee joint between young healthy, non-athletic female and male individuals. SUBJECTS AND DESIGN: MR imaging was performed in 18 healthy subjects without local or systemic joint disease (9 female, age 22.3 +/- 2.4 years, and 9 male, age 22.2 +/- 1.9 years.), using a fat-suppressed FLASH 3D pulse sequence (TR = 41 ms, TE = 11 ms, FA = 30 degrees) with sagittal orientation and a spatial resolution of 2 x 0.31 x 0.31 mm3. After three-dimensional reconstruction and triangulation of the knee joint cartilage plates, the cartilage thickness (mean and maximal), volume, and size of the articular surface area were quantified, independent of the original section orientation. RESULTS AND CONCLUSIONS: Women displayed smaller cartilage volumes than men, the percentage difference ranging from 19.9% in the patella, to 46.6% in the medial tibia. The gender differences of the cartilage thickness were smaller, ranging from 2.0% in the femoral trochlea to 13.3% in the medial tibia for the mean thickness, and from 4.3% in the medial femoral condyle to 18.3% in the medial tibia for the maximal cartilage thickness. The differences between the cartilage surface areas were similar to those of the volumes, with values ranging from 21.0% in the femur to 33.4% in the lateral tibia. Gender differences could be reduced for cartilage volume and surface area when normalized to body weight and body weight x body height. The study demonstrates significant gender differences in cartilage volume and surface area of men and women, which need to be taken into account when retrospectively estimating articular cartilage loss in patients with symptoms of degenerative joint disease. Differences in cartilage volume are primarily due to differences in joint surface areas (epiphyseal bone size), not to differences in cartilage thickness.

Adult↗

PubMed2001

Primary lymphoma of the conjunctiva--a rare manifestation of indolent non-Hodgkin's lymphoma.

Lymphoid tumours of the conjunctiva are extremely rare. Such tumours can appear as an isolated neoplasm or as part of a systemic disease. We describe the clinical and histopathologic findings of a patient with bilateral conjunctival lymphoma who presented with a 5-year history of chronic conjunctivitis. After clinical staging, including (1) thoracic and abdominal computerised tomography scans, (2) magnetic resonance tomography of the brain and orbita, (3) fibre-optic gastrointestinoscopy, (4) colonoscopy and (5) bone marrow biopsy,.no other foci of the lymphoma were found. The patient received radiation therapy and achieved complete remission. We conclude that conjunctival lymphoma should be included in the differential diagnoses of chronic conjunctivitis. Persisting signs and symptoms of conjunctivitis not responding to standard treatment should prompt biopsy.

Biopsy↗

PubMed2001

Evaluation of breast lesions by power Doppler sonography.

The aim of this study was to determine the value of power Doppler sonography in the detection of tumor vascularity in breast lesions and to find new diagnostic criteria for differential diagnosis. Power Doppler sonography was prospectively performed in 102 patients with 118 histologic (n = 116) and cytologic (n = 2) results. A semisubjective scoring system for the intratumoral increase in blood flow compared with the flow in normal breast parenchyma (reference structure) was introduced and the flow pattern registered. The difference in the flow increase for benign and malignant breast disease was highly significant (p < or = 0.0001). This applied especially to invasive cancer above a maximum tumor diameter of 5 mm excluding cancer stage Tis and T1a. A positive correlation between cancer size and flow increase were found. The flow pattern was an additional feature. The sensitivity was calculated to be between 74.5 and 78.8%, and the specificity between 74.6 and 77.8%. The level of flow increase in Power Doppler sonography is an important feature in the differential diagnosis of breast lesions and should be considered together with the established criteria in B-mode ultrasound. The flow pattern might also add some important information.

Adolescent↗

PubMed2001

Diffusion-weighted imaging of tumor recurrencies and posttherapeutical soft-tissue changes in humans.

The aim of this study was to examine soft tissue tumor recurrences and posttherapeutic soft tissue changes in humans with a diffusion-weighted steady-state free precession (SSFP) sequence. Twenty-four patients with 29 pathologies of the pelvis or the extremities were examined. The lesions were classified as follows: group 1, recurrent viable tumors (n = 10); group 2, postoperative hygromas (n = 7); and group 3, posttherapeutic reactive inflammatory muscle changes (n = 12). The sequence protocol in these patients consisted of short tau inversion recovery images, T2-weighted spin-echo (SE), pre- and postcontrast T1-weighted SE images and the diffusion-weighted SSFP sequence. The signal loss on diffusion-weighting was evaluated visually on a four-grade scale and quantitatively. The signal intensities were measured in regions of interest and a regression analysis was performed. Statistical analyses was performed utilizing the Student's t-test. The signal loss was significantly higher for hygromas and edematous muscle changes than for recurrent tumors (p < 0.001) indicating higher diffusion of water protons. The regression coefficient was -0.11 (mean) for tumors. Hygromas had a significantly higher signal loss than inflammatory edematous muscle changes (p < 0.01). The regression coefficients were -0.29 (mean) for hygromas and -0.22 (mean) for edematous muscle changes. The SSFP sequence seems to be a suitable method for diffusion-weighted imaging of the musculoskeletal system in humans. These preliminary results suggest that the signal loss and the regression coefficients can be used to characterize different types of tissue.

Adult↗