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R Brüning

Publications and source records attributed to R Brüning.

At least 19 recordsLinked to original sources
PubMed2002

[University clinics as centers of radiologic performance alliances in the ambulatory and inpatient sector].

PROBLEM: Health care delivery in Germany has to face severe challenges that will lead to a closer integration of services for in- and out-patients. University hospitals play an important role due to their activities in research, education and health care delivery. They are requested to promote and evaluate new means and ways for health care delivery. METHODS: The Institute of Clinical Radiology at the University Hospital of the Ludwig-Maximilians-University started teleradiological services for hospitals and general practices in January 1999 in the framework of the "Imaging services--teleradiological center of excellence". Legal, technical and organizational prerequisites were analyzed. RESULTS: Networks between university hospitals and general practices are not likely to solve all future problems. They will, however, increase the availability of the knowledge of experts even in rural areas and contribute to a quality ensured health care at the patients home. Future developments may lead to international co-operations and such services may be available to patients abroad. CONCLUSION: Legal, technical and organizational obstacles have to be overcome to create a framework for high quality telemedical applications. University hospitals will play an important role in promoting and evaluating teleradiological services.

Delivery of Health Care↗
PubMed2002

[Diagnostic evaluation of the craniocervical vascular system with a 16-slice multi-detector row spiral CT. Protocols and first experiences].

PURPOSE: The newly developed 16-slice multi detector row computed tomography (MDCT) allows for isotropic imaging at rotation times under 500 ms. We aim to describe our first experiences with this novel technology in the diagnostic imaging of the craniocervical vascular system. METHODS: The craniocervical vascular system of 8 consecutive patients was examined with a standardized protocol with the new 16-slice MDCT. The volume covered included the carotid arteries from their origin at the aortic arch and the intracranial arterial and venous vessels in their entirety. Homogeneity of contrast, contrast-to-parenchyma ratios, image quality and radiation doses were assessed. RESULTS: A homogeneous vessel-to-parenchyma ratio was reached in the carotids as well as in the intracranial arterial and venous vessels. Image quality was rated as excellent in all patients. The estimated mean effective radiation dose amounted to 2.31 mSv +/-0.57, the mean dose length product to 608 mGy*cm +/-151. CONCLUSION: The newly developed 16-slice MDCT technology appears to be a promising tool in the diagnostic assessment of the cervicocranial vessels.

Aged↗
PubMed2002

Dynamic susceptibility contrast-enhanced echo-planar imaging of cerebral gliomas. Effect of contrast medium extravasation.

PURPOSE: To assess the influence of the degree of contrast medium extravasation on different DSC EPI MR sequences for perfusion MR imaging. MATERIAL AND METHODS: 60 patients with cerebral gliomas were examined by either an FID EPI or an SE EPI DSC MR sequence. The acquired images were evaluated on a qualitative and quantitative basis. For qualitative assessment, the homogeneity of the signal time curve, image artifacts, the degree of signal drop and the degree of enhancement were evaluated. The quantitative assessment included the percentage of signal drop and the contrast-to-noise ratio of the different EPI sequences was analyzed. RESULTS: FID EPI presented a more homogeneous signal time curve and a more pronounced susceptibility effect than the SE EPI sequence. Due to the lesser susceptibility effect, the SE EPI sequence was not as sensitive to contrast media extravasation. The signal returned to baseline in all patients. In patients with strongly enhancing lesions, the FID EPI sequence suffered from considerable T1 effects, causing problems in the quantification of perfusion data. CONCLUSION: FID EPI sequences were preferred for perfusion MR imaging in patients without strong enhancing lesions, e.g. in ischemia or tumors with intact blood-brain barrier. In patients with suspected strong enhancing lesions, an SE EPI sequence should be used.

Brain Neoplasms↗
PubMed2001

Case-oriented computer-based-training in radiology: concept, implementation and evaluation.

BACKGROUND: Providing high-quality clinical cases is important for teaching radiology. We developed, implemented and evaluated a program for a university hospital to support this task. METHODS: The system was built with Intranet technology and connected to the Picture Archiving and Communications System (PACS). It contains cases for every user group from students to attendants and is structured according to the ACR-code (American College of Radiology) 2. Each department member was given an individual account, could gather his teaching cases and put the completed cases into the common database. RESULTS: During 18 months 583 cases containing 4136 images involving all radiological techniques were compiled and 350 cases put into the common case repository. Workflow integration as well as individual interest influenced the personal efforts to participate but an increasing number of cases and minor modifications of the program improved user acceptance continuously. 101 students went through an evaluation which showed a high level of acceptance and a special interest in elaborate documentation. CONCLUSION: Electronic access to reference cases for all department members anytime anywhere is feasible. Critical success factors are workflow integration, reliability, efficient retrieval strategies and incentives for case authoring.

Computer Communication Networks↗
PubMed2001

[Exclusion of coronary calcium with electron beam tomography: an effective filter before invasive diagnosis in symptomatic patients?].

Electron beam computed tomography (EBCT) is the most sensitive and accurate method of measuring coronary calcium which indicates coronary atherosclerosis. We performed a prospective study in 1764 symptomatic patients who were referred to our hospital for coronary angiography because of suspected coronary artery disease. In all of these patients cardiac catheterization and coronary calcium scanning was performed within 3.2 +/- 4 days. 454/1225 men (37.0%) and 165/539 women (30.6%) had significant coronary stenoses > or = 75%. Only two men (0.4%) and no single woman (0.0%) with stenoses > or = 75% and only 3/323 patients (0.9%) with moderate stenoses (50-75%) did not exhibit coronary calcium. Coronary angiography excluded stenoses in 822 patients. Of these patients 261 (29.4%) did not reveal coronary calcium. In younger patients (< 60 years) without stenosis exclusion of coronary calcium was a frequent finding: 31% of men and 55.8% of women were free of coronary calcium. Thus, exclusion of coronary calcium with electron beam tomography defines a substantial subgroup of patients who have an extremely low risk of significant coronary stenosis despite suspected coronary artery disease in history and non-invasive testing. Determination of coronary calcium might, therefore, be an effective filter before invasive angiography in selected groups of symptomatic patients.

Adult↗
PubMed2001

Correlation of coronary calcification and angiographically documented stenoses in patients with suspected coronary artery disease: results of 1,764 patients.

OBJECTIVES: This study correlated the electron beam computed tomographic (EBCT) calcium scores with the results of coronary angiography in symptomatic patients in order to assess its value to predict or exclude significant coronary artery disease (CAD). BACKGROUND: Electron beam computed tomography is a sensitive method to detect coronary calcium. However, it is unclear whether it may play a role as a filter before invasive procedures in symptomatic patients. METHODS: A total of 1,764 patients (1,225 men and 539 women) with suspected CAD from a single center were included in our study. All patients underwent calcium screening with EBCT (C150XP Imatron) and conventional coronary angiography. RESULTS: Fifty-six percent of men and 47% of women revealed significant coronary stenoses (> or =50%). Total exclusion of coronary calcium (14% of the study group) was associated with an extremely low probability of stenosis (<1%). With calcium scores > or =20th, > or =100th or > or =75th percentile of age groups, the sensitivity to detect stenoses decreased to 97%, 93% and 81%, respectively, in men and to 98%, 82% and 76%, respectively, in women. At the same time, the specificity increased up to 77% in men and women. There was a significant difference in coronary calcium between men and women in all age groups; however, receiver-operating characteristic curves indicated that the test can be performed with equal accuracy in all of these subgroups. CONCLUSIONS: Calcium screening with EBCT is a highly sensitive and moderately specific test to predict stenotic disease. Exclusion of coronary calcium defines a substantial subgroup of patients, albeit symptomatic, with a very low probability of significant stenoses.

Adult↗
PubMed2001

[Value of multiplanar reformations (MPR)in multi-slice spiral CT of the lung].

PURPOSE: To evaluate the quality of multiplanar reformations (MPR) of multidetector spiral-CT (MD-CT) data sets of the chest based on anatomic criteria. METHODS: 90 patients with suspected or known diseases of the lung parenchyma underwent thoracic MD-CT with 1-mm collimation. Axial scans were reconstructed with 1-mm slice width and 0.6-mm reconstruction increment. Coronal and sagittal MPRs were reconstructed with 3, 5 and 8 mm thickness from the axial scans. Three blinded readers rated image quality based on several anatomic criteria and the presence of different artifacts using a 5-point scale. The scores for MPRs were compared with those of 5-mm thick axial scans. RESULTS: All anatomical structure were equally well depicted on MPRs as on axial scans with very good interobserver correlation (kappa 0.69-0.76). Only the lung parenchyma directly adjacent to the heart and the great vessels were visualized with limited quality due to cardiac pulsation artifacts. Advantages of sagittal MPRs include the sharper delineation of interlobar fissures and thus improved anatomic localization of a lesion. Coronal reformations also offer improved anatomic orientation in comparison with 5-mm axial scans. A slice thickness of 5 mm for MPRs yielded best results. CONCLUSIONS: MPRs allow an unrestricted assessment of the lung. Sagittal and coronal reformations improve the topographical visualization of chest anatomy.

Adult↗
PubMed2001

[Diagnostic value of different rectal contrast media in the detection of colorectal diseases by multi-slice CT].

PURPOSE: Assessment of 3 different rectal contrast agents (water, methylcellulose, ultrasound gel) for their suitability for colorectal imaging in multislice CT (MS-CT). METHODS: 115 patients with colorectal diseases underwent MS-CT with varying, rectal contrast agents in a prospective study. Images were assessed by 2 independent CT-experienced radiologists. 6 criterias were evaluated, using a 5-point scale. RESULTS: Methylcellulose (MC) proved to be significantly superior to ultrasound gel (US). Especially, differentiation of healthy and diseased bowel and bowel wall and lumen were aided, which was proven by quantitative analysis of attenuation values. Rectal distension is greater using MC or US than for water. More proximal parts of the colon could be better distended with water. The interobserver correlation was good (kappa 0.76). CONCLUSIONS: Rectal filling with MC significantly improves diagnostic confidence in colorectal examinations. Ease of administration and lack of problems suggest its use as a clinical routine tool.

Adult↗
PubMed2001

ECG-gated reconstructed multi-detector row CT coronary angiography: effect of varying trigger delay on image quality.

PURPOSE: To evaluate the effectiveness of electrocardiographically (ECG)-gated retrospective image reconstruction for multi-detector row computed tomographic (CT) coronary angiography in reducing cardiac motion artifacts and to evaluate the influence of heart rate on cardiac image quality. MATERIALS AND METHODS: Sixty-five patients with different heart rates underwent coronary CT angiography. Raw helical CT data and ECG tracings were combined to retrospectively reconstruct at the defined consecutive z position with a temporal resolution of 250 msec per section. The starting points of the reconstruction were chosen between 30% and 80% of the R-R intervals. The relationships between heart rate, trigger delay, and image quality were analyzed. RESULTS: Optimal image quality was achieved with a 50% trigger delay for the right coronary artery and 60% for the left circumflex coronary artery. Optimal image quality for the left anterior descending coronary artery was equally obtained at 50% and 60% triggering. A significant negative correlation was observed between heart rate and image quality (P <.05). The best image quality was achieved when the heart rate was less than 74.5 beats per minute. CONCLUSION: To achieve high image quality, the heart rate should be sufficiently slow. Selection of appropriate trigger delays and a decreasing heart rate are effective to reduce cardiac motion artifacts.

Adult↗
PubMed2001

Correlations between clinical findings and magnetization transfer imaging metrics of tissue damage in individuals with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

BACKGROUND AND PURPOSE: We obtained magnetization transfer imaging (MTI) scans from individuals with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) (1) to investigate the presence, extent, and nature of pathology in white and gray matter outside proton density (PD)-visible lesions; (2) to quantify the degree of tissue damage occurring in lesions seen on PD-weighted scans; and (3) to correlate MTI-derived measures of disease burden with age, physical disability, and cognitive performance. METHODS: Dual-echo, T1-weighted, and MTI scans of the brain were obtained from 33 individuals with CADASIL and 12 control subjects. Magnetization transfer ratio (MTR) values from PD-visible lesions, normal-appearing white matter (NAWM), and normal-appearing gray matter (NAGM) were measured. Histograms of MTR from the whole brain and normal-appearing brain tissue were also produced. RESULTS: All MTR values from NAWM and NAGM regions studied were significantly lower for individuals with CADASIL than for control subjects, with the exception of those obtained from the NAWM of the infratentorial structures and the NAGM of the occipital cortex. The average MTR from PD lesions in individuals with CADASIL was significantly lower than that from all the NAWM regions. Average MTR and peak location from whole-brain and normal-appearing brain tissue histograms were significantly lower for individuals with CADASIL than for control subjects. MTR values from NAWM were strongly correlated with the extent of macroscopic lesions and their average MTR. Apart from NAGM, average MTR from all other tissues studied significantly decreased with increasing age, physical disability, and cognitive impairment. CONCLUSIONS: PD lesions of individuals with CADASIL have variable degrees of tissue damage. Brain tissue outside PD abnormalities is also damaged. This study suggests that the extent and the severity of the brain tissue damage are critical factors in determining clinical status in CADASIL.

Age Factors↗
PubMed1999

Quantitative MRI in CADASIL: correlation with disability and cognitive performance.

OBJECTIVE: To study correlations between total lesion load on brain MRI and clinical features, and to evaluate the influence of demographic variables on quantitative MRI variables in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). BACKGROUND: CADASIL is a hereditary form of small-vessel disease caused by mutations within the Notch3 gene. MRI abnormalities have been found both in asymptomatic and symptomatic CADASIL individuals. METHODS: Quantitative measurements on cerebral MRI were performed in 64 CADASIL individuals. MRI lesions were quantified using a semi-automated segmentation technique based on local thresholds. RESULTS: MRI total lesion volume correlated significantly with disability (Rankin Scale) on both T1- and proton density (PD)-weighted images. There was a significant inverse correlation between total lesion volume and overall cognitive performance as determined by the Mini-Mental State Examination. Age but not sex was correlated with lesion load both on T1- and PD-weighted images. There was no detectable influence of the Notch3 genotype on quantitative MRI variables. CONCLUSIONS: This study demonstrates correlations between MRI lesion volume and clinical characteristics in CADASIL. Longitudinal studies are now warranted to investigate whether quantitative MRI could be used as an adjunct outcome measure in future therapeutic trials in CADASIL.

Adult↗
PubMed1999

[Computed tomography of the abdomen with multidetector-array CT].

BACKGROUND: The advent of multidetector CT (MDCT) constitutes a quantum leap creating a wealth of new opportunities in medical imaging. However, while the basic principles of spiral CT still apply, we are now challenged to rethink our strategies in planning a CT study to take full advantage of the increased capabilities of MDCT. MATERIALS AND METHODS: We report here our preliminary experiences with MDCT for abdominal CT imaging within a 5-month period. During this time, suitable protocols for investigation of the abdomen using MDCT were developed. The capabilities of MDCT allow for tailoring dedicated CT protocols for routine applications as well as for biphasic liver studies and CT angiography of the aorta and abdominal vessels. RESULTS: The speed of MDCT can either be used to reduce the time needed to cover a given volume, or to use narrower beam collimations to increase the resolution of detail along the z-axis and reduce volume averaging. Higher scan speed allows reduction of the amount of contrast material in vascular applications and suppression of motion artifacts. Higher spatial resolution with thinner collimations reduces volume averaging and improves the detection of small hepatic and pancreatic lesions. Detailed analysis of vascular structures and high-quality three-dimensional reformations become feasible. New problems arise from the large amount of data generated by MDCT. CONCLUSIONS: MDCT offers a wealth of new opportunities that help us to come to a fast and accurate diagnosis in suspected abdominal disease. Traditional indications for performing CT are reemphasized and new clinical applications can be exploited.

Abdomen↗
PubMed1999

[The technical bases and uses of multi-slice CT].

In this review the technical principles and applications of multi-slice CT are discussed. Multi-slice CT systems allow simultaneous acquisition of up to 4 slices by using multi-row detector systems. Intuitive geometrical arguments are used to establish the limitation to a maximum of 4 slices which is kept by all currently existing multi-slice CT systems. Two different construction principles of the detector are discussed, the "Fixed Array" detector and the "Adaptive Array" detector. The extension of conventional 360 LI and 180 LI spiral interpolation techniques to multi-slice spiral CT is explained as well as a new generalized multi-slice spiral weighting concept, the so-called "Adaptive Axial Interpolation". Several techniques to improve multi-slice spiral image quality are discussed. Finally, some examples for clinical applications are given, and the principle of ECG triggered and ECG gated cardiac examinations with optimized temporal resolution is presented. Multi-slice CT systems are a milestone with respect to increased volume coverage, shorter scan times, improved axial (longitudinal) resolution and better use of the X-ray tube output. Additionally, new clinical applications are possible such as Cardiac CT.

Electrocardiography↗
PubMed1999

[The diagnosis of stages T1 and T2 in laryngeal carcinoma with multislice spiral CT].

The purpose of the study was to preoperatively investigate small laryngeal carcinomas using multi-slice spiral CT (MSCT) and subsequent multiplanar reconstructions (MPR) and to compare the results to the detailed spread found at surgery and histology. Nine patients with small (T1, T2) laryngeal cancer were investigated on a MSCT scanner (Siemens plus 4 Volume Zoom, Siemens). A 4 x 1 mm collimation, 120 kV, 200 mAs and a 0.5 seconds rotation time were used, allowing a coverage of the entire larynx in approximately 10 seconds within a single breathhold. Multiplanar reconstruction's (MPR) in sagittal and coronal plane were reconstructed in all patients and rated in consensus reading. In 8 of nine patients, the glottic spread was detected by MSCT, in one cause of a supraglottic tumor a glottic invasion was excluded. The infiltration of the anterior commissure, the infiltration into the subglottic space and the extension into the hypopharynx was correctly assessed in all patients. MSCT was not able to predict infiltration of the arythnoids in two patients. The use of multi-slice spiral CT for the preoperative assessment of small laryngeal tumors shows great promise. The detection or exclusion of subtle spread of these tumors into the supra- or subglottic space and along the glottic level was possible with high accuracy. As the examination time is short, artifacts are rare and multiplanar reconstructions gain in clinical importance.

Carcinoma↗