Biomedical subjects

Roland Bruening

Publications and source records attributed to Roland Bruening.

9 recordsLinked to original sources

PubMed2005

Nucleosomes in serum of patients with early cerebral stroke.

BACKGROUND: Nucleosomes are cell death products that are elevated in serum of patients with diseases that are associated with massive cell destruction. We investigated the kinetics of circulating nucleosomes after cerebral stroke and their correlation with the clinical status. METHODS: In total, we analyzed nucleosomes by ELISA in sera of 63 patients with early stroke daily during the first week after onset. For correlation with the clinical pathology, patients were grouped into those with medium to slight functional impairment (Barthel Index BI >or=50) and those with severe functional impairment (BI<50). RESULTS: Patients with BI >or=50 showed a continuous increase in nucleosomes until day 5 (median: 523 arbitrary units, AU) followed by a slow decline. In contrast, patients with BI<50 showed a steeper initial increase reaching a maximum already on day 3 (869 AU). Both, days after stroke (p < 0.001) and BI (p < 0.001), had a significant influence on nucleosome concentrations, respectively. Consistently, patients with BI<50 had a significantly larger area under the curve (AUC/day) of nucleosome values during the first week after stroke (800 AU) than patients with BI >or=50 (497 AU; p=0.031). Concerning the infarction volume, nucleosomes showed significant correlations for the concentrations on day 3 (r=0.43; p=0.001) and for the area under the curve (r=0.34; p=0.016). CONCLUSION: Even if nucleosomes are nonspecific cell death markers, their release into serum after cerebral stroke correlates with the gross functional status as well as with the infarction volume and can be considered as biochemical correlative to the severity of stroke.

Adult↗

PubMed2005

Prospective, multireader evaluation of image quality and vascular delineation of multislice CT angiography of the brain.

The aim of this prospective, multireader trial was to investigate image quality and vascular delineation of cranial multislice CT angiography (MSCTA) to identify strengths and weaknesses of the method. Sixty consecutive patients underwent standardized cranial MSCTA. The mean estimated effective dose was 0.96+/-0.11 mSv. Three masked readers independently graded image quality parameters and vascular delineation on a 5-point scale. Vascular attenuation values and dose-length products were assessed quantitatively. Quantitative parameters were evaluated with a proportional odds regression model with bootstrapped standard errors to adjust the relevant standard errors for correlation within subjects and across readers. The non-parametric Wilcoxon sign-rank test was applied for quantitative measurements. Good to excellent ratings were observed regarding image quality parameters and vascular delineation. The delineation of veins was rated higher than that of arteries (OR 2.00). Smaller arterial segments were rated significantly less favorably than larger segments (OR up to 26.98). Moreover, the cavernous sinus, the C2 segment of the ICA and the communicating arteries demonstrated lower scores. Attenuation values were >240 HU and vessel-to-parenchyma ratios >7 in all vessels. Cranial MSCTA achieved high ratings regarding image quality and vascular delineation. Relative weaknesses were found in small arterial subsegments and in vessels in close topographical proximity to bone.

Adolescent↗

PubMed2004

Blurring of the vessels of the interhemispheric fissure in multislice CT angiography: a sign of meningeal carcinomatosis.

Meningeal carcinomatosis remains a challenging diagnosis to make, with both cerebrospinal fluid (CSF) analysis and radiological methods having a limited sensitivity. We aimed at describing a possible diagnostic sign of multislice CT angiography (MS-CTA) in the diagnosis of meningeal carcinomatosis. Upon retrospective analysis of MSCT angiographies of the brain, a conspicuous sign of the vessels of the interhemispheric fissure was noted in five patients. Cranial MSCT angiographies were performed with a standardized protocol (120 kV, 200 mA s, collimation of 4x1 mm, table feed per rotation 4 mm). We injected 120 ml of nonionic contrast medium as a bolus, and data acquisition was started after a fixed delay of 35 s. In order to elucidate the finding, correlation with clinical follow-up and/or CSF findings was performed for all patients. In five patients there was a blurring, an increased number, and a pathologic configuration of the vessels of the interhemispheric fissure. All five patients with this sign had clinical signs and symptoms of meningeal carcinomatosis. Three patients had positive CSF cytology, one further patient had follow-up spinal MRI 6 weeks later demonstrating meningeal carcinomatosis. One patient declined lumbar puncture. MS-CTA has the capacity to demonstrate a pathologic configuration of the vessels of the interhemispheric fissure in patients with meningeal carcinomatosis. This sign may serve as an indicator of meningeal carcinomatosis and should raise the suspicion of this disease entity.

Cerebral Angiography↗

PubMed2004

[Comparison of gradient echo and echo planar imaging measurements for the calculation of regional blood volume maps].

The purpose of this study was to evaluate relative regional blood volume (rCBV) in meningioma and compare the utility of reconstruction using both gradient-echo sequence and echo-planar-imaging (EPI) sequence. Eighteen patients with meningiomas were studied on a Siemens 1.5-T scanner. During the gradient-echo sequence (n=12) and EPI sequence (n=6), a bolus (0.2 mmol/kg) of Gd-DTPA was injected mechanically with a flow rate of 5 ml/second. Image processing of dynamic data was performed on a pixel-by-pixel basis. The ratio of tumor rCBV/gray matter rCBV was 3.01 +/- 1.18 (3.07 +/- 1.39 in gradient sequence and 2.84 +/- 0.94 in EPI sequence). The ratio of gray matter/white matter as the reference tissue had a mean of 2.79 +/- 0.76 using the FLASH sequence, and a mean of 3.04 +/- 1.31 using EPI. These differences were not statistically signifcant (P>0.5, t-test). According to the ratio of tumor rCBV/gray matter rCBV, a mean value, 14.5 ml/100 g, of rCBV in meningiomas was calculated. Compared with gray matter, increased inhomogeneous rCBV was observed in meningioma. Based on the two different sequences, no bias can be observed in our rCBV reconstruction.

Adult↗

PubMed2003

Optimal contrast application for cardiac 4-detector-row computed tomography.

RATIONALE AND OBJECTIVES: This study was designed to determine the optimal contrast protocol for 4-detector-row computed tomography angiography of the heart. METHODS: Sixty patients were randomly assigned to 1 of 4 groups with 300 and 400 mg/mL iodine concentrations and 2.5 and 3.5 mL/s flow rates. Contrast density was measured in the left ventricular cavity and coronary arteries. RESULTS: Low iodine concentration injected at slow flow rate (0.75 g iodine/s) resulted in acceptable contrast enhancement in only 53.8% of the patients. There was no significant difference between low contrast concentration injected at high flow rate and high contrast concentration injected at slow flow rate ( approximately 1 g iodine/s). High contrast concentration administered with high flow rates (1.4 g iodine/s) may result in an enhancement above 350 Hounsfield units (HU) and interfere with coronary calcifications. CONCLUSIONS: The injection of approximately 1 g iodine/s resulted in an optimal (250-300 HU) contrast enhancement for cardiac 4-detector-row computed tomography.

Adult↗

PubMed2002

Intraindividual comparison of contrast-enhanced electron-beam computed tomography and navigator-echo-based magnetic resonance imaging for noninvasive coronary artery angiography.

The aim of this study was to compare contrast-enhanced electron-beam computed tomography (EBCT) and navigator-echo-based MRI of the coronary arteries in the same patient population. Both methods were assessed for visualization of the coronary arteries and their diagnostic accuracy in identifying significant coronary artery stenoses compared with conventional coronary angiography. Twenty patients with known coronary artery disease were examined with both contrast-enhanced EBCT and a respiratory-gated MRI sequence. A grading system was used to evaluate the image quality. Sensitivity and specificity for the detection of significant coronary artery stenoses was evaluated compared with conventional coronary angiography. With EBCT, 89% of the main coronary arteries could be completely visualised in the proximal and middle segments; with MRI, 83% were visualised. With EBCT the sensitivities for identifying significant (>/=50%) stenoses in proximal and middle vessel segments were 75% in the main stem, 88% in the left anterior descending coronary artery, 75% in the left circumflex coronary artery, and 90% in the right coronary artery. Respective sensitivities for MRI angiograms were 75, 82, 75 and 80%. With both modalities a sufficient image quality of the main coronary arteries can be obtained in most cases. The diagnostic capability for detecting significant stenoses is comparable for both methods.

Contrast Media↗

PubMed2002

Coronary artery calcium: absolute quantification in nonenhanced and contrast-enhanced multi-detector row CT studies.

PURPOSE: (a) To determine the accuracy of multi-detector row computed tomography (CT) in the measurement of the calcium concentration in a cardiac CT calibration phantom and (b) to assess the correlation of a traditional 3-mm section width CT coronary screening protocol and a 1.25-mm section width CT angiography imaging protocol in the quantification of the absolute mass of coronary calcium in patients who underwent both coronary screening and CT angiography with a multi-detector row CT scanner. MATERIALS AND METHODS: A heart phantom containing calcified cylinders was scanned to determine calibration factors and absolute calcium mass. In 50 patients, the variability (value 1 - value 2/mean value 1 - value 2), limit of agreement (+/-2SD value 1 - value 2), and systematic error (mean value 1 - value 2) of the total amount of coronary calcium calculated at traditional 3-mm section width CT and at 1.25-mm section width CT angiography were determined. RESULTS: The correlation coefficient between the 3-mm section width, nonenhanced protocol and the 1.25-mm section width CT angiography protocol was very high (r = 0.977) and the mean variability was low (19.7%) for the absolute mass. There was a systematic error of -6.7 mg and a limit of agreement between 45.0 mg and -58.5 mg. CONCLUSION: Use of the mass quantification algorithm in combination with a calibration phantom allows accurate quantification of coronary calcium. Measurements of calcium mass obtained at 1.25-mm section width CT angiography have the best agreement with those obtained at the traditional 3-mm section width imaging protocol.

Algorithms↗

PubMedDate not supplied

Multiplanar reformat display technique in abdominal multidetector row CT imaging.

The purpose of this study was to evaluate the image quality and diagnostic value of multiplanar reformat (MPR) of abdominal CT performed with multidetector row spiral technique (MDCT). Forty-five patients were referred for an abdominal MDCT angiography. No significant differences in image quality and in the number of lesions detected were found between axial and MPR images (t-test, P>.90 and chi-square, P>.95). Additional diagnostic value to axial images could be obtained with MPR display.

Adult↗

PubMedDate not supplied

CT/fluoroscopy-guided transthoracic needle biopsy: sensitivity and complication rate in 98 procedures.

PURPOSE: The purpose of this study was to evaluate CT/fluoroscopy (CTF)-guided core needle biopsies (CNBs) in the thorax. METHOD: Ninety-eight biopsies were performed using a core biopsy needle (18G) with a reusable biopsy gun under CT/F. All results were compared to surgery plus histology or to clinical follow-up of >12 months. Sensitivity, specificity, and negative predictive value (NPV) were calculated. RESULTS: For pulmonary biopsies, sensitivity was 94%, specificity 100%, and NPV 73%; no significant correlation between the pneumothorax rate and the intrathoracic penetration depth was found. For biopsies of the mediastinum and pleura, sensitivities were 87 and 80%, respectively; specificity was 100% in both locations. A pneumothorax occurred in 21%, a pneumothorax requiring drainage in 2.0%. CONCLUSION: CT/F-guided CNB is a reliable method to obtain thoracic biopsies, with a complication rate of 2.0%.

Adult↗