Ear reconstruction supported by a stereolithographic model.
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Cartilage↗
Biomedical subjects
R Brüning
Publications and source records attributed to R Brüning.
Simultaneous brachial diplegia and rotational vertigo due to combined spinal anterior and vertebrobasilar embolism.
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Arm↗
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↗
[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↗
[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↗
[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↗
[Imaging of the thorax with multislice spiral CT].
With multislice spiral computed tomography (MSCT), existing indications for performing CT of the chest are strengthened and new applications are emerging. The high speed of MSCT improves efficiency, image quality and patient comfort of "routine" imaging of the chest. The ability to cover large volumes with thin slices improves the evaluation of mediastinal lymph nodes and pulmonary nodules and allows for high-quality secondary reconstruction. If a comprehensive diagnosis of the mediastinal structures and the pulmonary parenchyma is desired, MSCT for the first time allows reconstruction of contiguous and high-resolution (HRCT) sections from the same set of thin-collimation raw data. This way, contiguous chest images of superior and HRCT sections of equal image quality compared to conventional CT scanning can be obtained. Vascular protocols greatly benefit from the high speed of MSCT: For imaging the thoracic aorta or pulmonary emboli (PE), the amount of contrast material can be substantially reduced. Owing to thin collimation, the detection rate of small peripheral emboli can be significantly increased. If indicated, the entire subphrenic venous system can be evaluated during the same session, without additional contrast material.
Adult↗
[Image analysis in multislice spiral CT of the lung with MPR and MIP reconstructions].
PURPOSE: To test, whether axial, coronal and sagittal MIP and MPR reconstructions of diagnostic quality can be obtained from 1-mm collimation MSCT data of the chest for the evaluation of thoracic anatomy and pathology. MATERIALS AND METHODS: 1-mm collimation MSCT scans were obtained with a pitch of 6 in an acrylic phantom and in 20 patients. Axial images were reconstructed with 0.6-mm increment. Multiplanar reformations (MPRs) and sliding thin-slab maximum intensity projections (STS-MIPs) were reconstructed in axial, coronal and sagittal planes. Images were printed in lung windows and evaluated by three readers by using a standardized evaluation scheme. RESULTS: Overall, both methods allowed good visualization of anatomic structures. MIP was superior for visualization of the pulmonary arteries (p < 0.05) while central and peripheral bronchi and the lung parenchyma were better depicted on multiplanar reconstructions. A confident diagnosis of thoracic pathology was feasible using both modalities, however MIPs appeared less usefull for evaluation of gross parenchymal abnormalities, such as pneumonic infiltrates or fibrotic changes. No significant difference in the degree of motion artifacts were detected between both modalities. CONCLUSION: MSCT data sets are ideally suited for generating MPR and MIP reconstructions. While MIPs are superior for the evaluation of thoracic vessels, MPR is advantageous for visualizing central and peripheral bronchi and the pulmonary parenchyma.
Humans↗
[Multislice computed tomography of the small intestine. Preliminary results].
SUBJECT: Spiral computer tomography (SCT) became an important supplement to the Sellink examination. Multi slice computer tomography (MSCT) achieves a z-axis resolution of 1-2 mm without considerable increase in the acquisition time. In this paper, examination technique in first clinical results of CT-Sellink examination with MSCT, including the 3D-reconstruction are presented. MATERIALS AND METHODS: The investigations were carried out with the Somatom Plus 4 Volume Zoom (Siemens, Forchheim) scanner. The following parameters were employed: 4 parallel detector ledges, collimation 4 x 1 mm, tube power 140 mA, tube voltage 120 kV, pitch 5 up to 6 mm, slice thickness 1 mm and 2 mm, reconstruction with 50% overlap. Via a duodenal tube, the small intestine was distended by means of 1.5 up to 2.5 l methyl-cellulose suspension. The data were acquired 35 s after injection of 120 ml contrast media (Ultravist). Various methods of postprocessing were applied on a workstation. RESULTS: As of yet, 16 patients were examined with MSCT-Sellink. In 4 cases pathological findings were detected with MSCT-Sellink, which were not recognized with X-ray Sellink. CONCLUSION: Due to high z-axis resolution and short acquisition time, the morphological details of the small intestine can be visualized utilizing MSCT-Sellink. The data set is well suited for 3D postprocessing. Improvement of diagnostic accuracy can be anticipated.
Adult↗
Echo-planar magnetic resonance imaging (EPI) with high-resolution matrix in intra-axial brain tumors.
The aim of this study was to assess the potential of high-speed interleaved echo-planar imaging (EPI) to achieve diagnostic image quality comparable to T2-weighted imaging in patients with brain tumors. Seventeen patients with intra-axial, supratentorial tumors (10 untreated gliomas, 7 radiated gliomas) were investigated on a 1. 5-T scanner. The conventional scan (SE, TR/TE = 2200/80 ms, 18 slices) was acquired in 8 min, 4 s, and EPI (TR/TE = 3000/80 ms, 18 slices) was completed in 25 s. The films were compared in a blinded trail by three radiologists. On the general impression and anatomic display, both sequences were rated to be of similar quality. Artifacts were slightly more pronounced at the skull base and around surgical clips using EPI. Tumor delineation was nearly equivalent using EPI, compared with the T2-weighted sequence. Echo-planar imaging reached diagnostic quality in all patients. Interleaved high-resolution EPI yielded sufficient quality to depict intra-axial, supratentorial brain tumors. Since EPI can be obtained in a small fraction of the time needed for conventional spin echo, in addition to other indications it could be considered to study patients unable to cooperate.
Artifacts↗
Misleading diagnosis of retroperitoneal actinomycosis.
A 34-year-old woman presented with a left-sided suprarenal space-occupying lesion on sonography. Culture of material obtained during sonographic-guided puncture of the retroperitoneal lesion yielded a mixed flora of Actinomyces and Peptostreptococcus. Initially, a misleading diagnosis of an adrenal pheochromocytoma was initiated by highly positive metaiodobenzylguanidine scintigraphy after chemical chemistry vanillylmandelic acid (VMA) test showed elevated values for adrenaline and its derivatives. Retroperitoneal actinomycosis with yet unproven spread into thoracic and cervical compartments is a particular unusual presentation of an infection with these organisms. Because it may mimic subacute infections or malignant masses in terms of clinical and laboratory findings, radiological diagnosis of this entity may be difficult. The diagnosis was based on results of culture and the response of the patient to long-term penicillin-derivate therapy after surgical drainage of the suprarenal abscess formation.
3-Iodobenzylguanidine↗
[Assessment of the effective dose for routine protocols in conventional CT, electron beam CT and coronary angiography].
PURPOSE: To compare the effective dose applied by sequential CT (SEQ), spiral CT (SCT), electron beam CT (EBT) and coronary angiography for investigations of the chest, abdomen and the heart. METHODS: The Alderson Phantom was used to compare the effective dose for all modalities. In addition, the effective dose for conventional CT (SEQ and SCT) was estimated with a mathematical phantom. RESULTS: For CT investigation of the chest and abdomen the dose was highest for the EBT (11 mSv and 25 mSv, respectively) and slightly lower for the SEQ (7.8 mSv and 21.5 mSv, respectively), whereas spiral CT required the least dose (5.3 mSv and 8.8 mSv, respectively). For coronary calcium screening (0.8 mSv) and EBT coronary angiography (1.7 mSv) the dose was lower than for coronary catheter angiography (3.3 mSv). For conventional CT the difference between the effective dose derived by the mathematical phantom and by the Alderson phantom was 2% to 20%. CONCLUSIONS: For investigations of the chest and abdomen the effective dose applied by SCT is significantly lower than that with EBT and SEQ. For investigation of the coronary arteries the effective dose applied by EBT is lower than that for coronary catheter angiography.
Body Burden↗
Characteristic MR lesion pattern and correlation of T1 and T2 lesion volume with neurologic and neuropsychological findings in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).
BACKGROUND AND PURPOSE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an arteriopathy related to a genetic defect of the notch 3 gene on chromosome 19. The purpose of this study was to evaluate lesion distribution and volume using MR imaging and to correlate the lesion volume with the neurologic and neuropsychological findings. METHODS: Twenty members of two families (14 with CADASIL as determined by linkage analysis, six healthy) were studied with MR imaging. Two observers evaluated the MR findings semiquantitatively and quantitatively. MR results were then correlated with neurologic and neuropsychological findings. RESULTS: A typical pattern of lesion distribution in patients with CADASIL was found: the frontal lobe was the site with the highest lesion load, followed by the temporal lobe and the insula. The total lesion volume on T1-weighted MR images correlated significantly with the degree of disability and the degree of impairment in neuropsychological functions (including attention, memory, and conceptual and visuospatial functions). CONCLUSION: In CADASIL patients, a common pattern of cerebral lesion distribution is found. The total T1 lesion volume is an important parameter to correlate with disability, as it may prove to be helpful in predicting the natural history of the disease.
Adult↗
Diffusion-weighted MRI in transient global amnesia: elevated signal intensity in the left mesial temporal lobe in 7 of 10 patients.
Prompted by the findings of previous studies with positron emission tomography and single photon emission computed tomography, which demonstrated hypoperfusion or hyperperfusion in the left temporal lobe in isolated patients with transient global amnesia (TGA), we compared the sensitivity of diffusion-weighted (DW) magnetic resonance imaging (MRI) with that of conventional T1- and T2-weighted MRI in patients with TGA. Ten patients with the typical syndrome of a pure TGA were included in the study. For all patients, a coronal DW sequence, a steady-state free precession (SSFP) sequence, and conventional T1- and T2-weighted turbo spin-echo sequences were obtained. Seven of the 10 patients had elevated signal intensity in the left hippocampal region on DW MRI; moreover, 3 of these 7 patients exhibited bilateral signal abnormality in this sequence. All conventional T1- and T2-weighted images as well as all follow-up studies were normal. The signal elevation in DW MRI correlates with a decrease in the interstitial space and with cellular edema in the temporal lobe during TGA. The underlying pathomechanism causing this cellular edema cannot be clearly outlined using DW MRI. Our data are, however, compatible with spreading depression. This is the first study to show that DW MRI is a sensitive MRI method for evaluating TGA, especially in the early stage of the disease.
Aged↗
The phenotypic spectrum of CADASIL: clinical findings in 102 cases.
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an increasingly recognized autosomal dominant disorder that leads to cerebrovascular manifestations in early adulthood. This study delineates the phenotypic spectrum and the natural history of the disease in 102 affected individuals from 29 families with biopsy-proven CADASIL. Recurrent ischemic episodes (transient ischemic attack [TIA] or stroke) were the most frequent presentation found in 71% of the cases (mean age at onset, 46.1 years; range, 30-66 years; SD, 9.0 years). Forty-eight percent of the cases had developed cognitive deficits. Dementia (28%) was frequently accompanied by gait disturbance (90%), urinary incontinence (86%), and pseudobulbar palsy (52%). Thirty-nine patients (38%) had a history of migraine (mean age at onset, 26.0 years; SD, 8.2 years), which was classified as migraine with aura in 87% of the cases. Psychiatric disturbances were present in 30% of the cases, with adjustment disorder (24%) being the most frequent diagnosis. Ten patients (10%) had a history of epileptic seizures. To delineate the functional consequences of ischemic deficits, we studied the extent of disability in different age groups. The full spectrum of disability was seen in all groups older than age 45. Fifty-five percent of the patients older than age 60 were unable to walk without assistance. However, 14% in this age group exhibited no disability at all. Kaplan-Meier analysis disclosed median survival times of 64 years (males) and 69 years (females). An investigation of the 18 multiplex families revealed marked intrafamilial variations.
Adult↗
[Radiation exposure during CT examination of thorax and abdomen. Comparison of sequential, spiral and electron beam computed tomography].
Comparison of radiation exposure applied by different types of CT scanners for the investigation of the chest and abdomen. Determination of radiation exposure applied by multi-phase spiral CT. Estimation of the dose in air in the system axis of the scanner, the CT dose index (CTDI) and the effective dose for electron beam tomography (EBT) and two conventional CT scanners (sequence, SEQ; spiral, SCT). For EBT, dose in system axis for investigation of the abdomen was above 50 mGy. Effective dose for investigation of the chest and abdomen was higher with EBT (11 and 26 mSv, respectively) than with conventional CT (SEQ, 4 and 20 mSv; SCT, 2 and 7 mSv). The effective dose for a biphasic investigation (liver 5 mSv, kidney 4 mSv) was below, for a triphasic investigation (liver 7 mSv) above the effective dose of the investigation of the abdomen (6 mSv). Investigation of the abdomen with the EBT should only be performed for certain indications. With spiral CT, effective dose is much lower than with EBT.
Abdomen↗
[Technical bases and acquisition conditions of electron-beam computed tomography].
PURPOSE: In this review the technical principle and scanner characteristics of electron beam computer tomography (EBCT) are discussed. METHODS: In contrast to conventional CT, image acquisition in EBCT is achieved without mechanically moving parts. This construction allows for short acquisition times in investigating given anatomical regions (100 ms per slice) or up to 8 levels without table movement and short interscan delays (50 ms per slice). RESULTS: Depending on the nature of the investigation, the scanner can be used in the single slice, continuous volume scanning and multi slice mode. The single slice mode is used for detection and quantification of coronary calcifications and for CT angiography of the coronary vessels. Equivalent to the spiral mode in conventional CT, continuous volume scanning may be used for routine investigation of the chest and abdomen. Functional investigations of the heart and perfusion measurement of different organs can be performed in multi slice mode. Because of the geometry of the electron beam scanner, radiation exposure for certain investigations is above the exposure with conventional CT. CONCLUSION: Future developments will focus on dose efficient radiation collimation, high resolution detector systems and artefact reducing reconstruction kernels.
Algorithms↗
[Significance of calcium detection with electron-beam tomography in coronary disease].
PURPOSE: Coronary calcium is a powerful indicator of arteriosclerosis and can be detected very precisely with electron beam tomography. The method can be applied in patients with known coronary artery disease or in asymptomatic patients at risk of arteriosclerotic disease. METHODS: The standard protocol of EBT consists of 30 to 40 slices of 3-mm thickness with a scan time of 100 ms, no overlap. No contrast medium is needed. The total scan can be performed within one breathhold. The calcium score is calculated as described by Agatston. Radiation exposure amounts to 0.8 mSv per total screen. We used spiral CT with and without ECG trigger as an alternative. RESULTS: At the University of Munich we performed an EBT scan of the heart in 1100 patients within the last year. In 567 patients coronary angiography was performed also (+/- 3 days). Confirming previous reports in the literature, we found a correlation of the calcium score with the age and gender of the patients. Severe coronary artery disease (stenoses > or = 75%) was associated with significantly more calcium than less severe CAD. The calcium score did not discriminate between one-, two- and three-vessel disease. The site of calcification does not correlate with the localization of stenoses. Thirty-three percent of the patients with significant coronary artery disease showed a normal age-adjusted calcium score; a total of 8.1% of patients with severe stenoses did not reveal any coronary calcification (score = 0). With asymptomatic patients there are only a few studies available. Soft plaques cannot be detected with EBT, but in most patients soft plaques occur together with hard plaques. Our results show that spiral CT of the newest generation may also be used for calcium screening. There was an excellent correlation of the calcium scores of EBT and spiral CT at all levels of calcification. DISCUSSION: Coronary calcium is a sensitive marker of coronary artery disease. In the clinical setting EBT is indicated in patients with known coronary artery disease (to evaluate prognosis), in patients who are unable to perform a stress test, and in patients with atypical chest pain. However, lack of calcification may be associated with severe stenoses in a minority of patients. The clinical value in asymptomatic patients needs to be defined: randomized studies are necessary. We see a possible indication in patients with known risk factors, in whom primary preventive strategies could be performed more selectively and cost-effectively.
Adolescent↗