Biomedical subjects

Paul Steiner

Publications and source records attributed to Paul Steiner.

4 recordsLinked to original sources

PubMed2006

A multicenter, site-independent, blinded study to compare the diagnostic accuracy of contrast-enhanced magnetic resonance angiography using 1.0M gadobutrol (Gadovist) to intraarterial digital subtraction angiography in body arteries.

PURPOSE: Prospective evaluation of diagnostic accuracy of single field-of-view contrast-enhanced MR Angiography (ceMRA) with 1.0M gadobutrol compared to intraarterial DSA in body arteries. MATERIALS AND METHODS: In an European multicenter study 179 patients underwent ceMRA and DSA. For each indication five prospectively defined vessel segments were evaluated by local investigators onsite and by three site-independent blinded readers (BR) independently. RESULTS: The agreement between ceMRA and DSA diagnosis was statistically significant in the onsite (96.6%) and blinded reader (86.6-90.2%) evaluation. Sensitivity, specificity, accuracy, positive (PPV) and negative predictive values (NPV) for detection of relevant stenosis (>50%) were calculated for the right and left internal carotid arteries, and common and external iliac arteries: Sensitivity was 95-98% (onsite) and 76-96% (BR), specificity 94-96% (onsite) and 86-94% (BR), accuracy 96% (onsite) and 87-93% (BR), NPV 98-99% (onsite) and 84-98% (BR), and PPV 79-93% (onsite) and 44-91% (BR), respectively. CONCLUSION: CeMRA of body arteries using 1.0M gadobutrol provides diagnostic information comparable to intraarterial DSA.

Adult↗

PubMed2002

Virtual endoscopy using spherical QuickTime-VR panorama views.

Virtual endoscopy needs some precomputation of the data (segmentation, path finding) before the diagnostic process can take place. We propose a method that precomputes multinode spherical panorama movies using Quick-Time VR. This technique allows almost the same navigation and visualization capabilities as a real endoscopic procedure, a significant reduction of interaction input is achieved and the movie represents a document of the procedure.

Colonography, Computed Tomographic↗

PubMed2001

Correlation of 3D MR coronary angiography with selective coronary angiography: feasibility of the motion-adapted gating technique.

The aim of this study was to verify the feasibility of a respiratory motion compensation technique (motion-adapted gating, MAG) for visualization of coronary arteries (CA) by correlation with selective coronary angiography (SCA). Fifteen subjects (11 patients, mean age 61.3 years, age range 41-73 years; and 4 healthy volunteers, mean age 32.3 years, age range 31-35 years) were investigated. A Philips Gyroscan ACS-NT was used, operating at 1.5 T, was combined with the PowerTrak 6000 gradient system. An ECG-triggered, respiratory motion-gated 3D turbo field echo sequence was used. The real-time algorithm utilized the concept of k-space weighting in combination with automatic analysis of respiratory motion. The main CA were investigated. Qualitative analysis was performed by three blinded investigators. Visibility was graded on a five-point scale (0=not visualized, 1=insufficient, 2=sufficient, 3=good, 4=excellent). Segments graded 2-4 were defined as adequately visualized. Sixty-two of 88 assessable CA segments in patient, and 22 of 32 in volunteer group were adequately visualized. Visibility of CA was classified as excellent for proximal RCA (avg. 3.6+/-0.5), good for LM, proximal LAD, proximal LCX, middle RCA and sufficient for middle LAD. Sensitivity, specificity, positive and negative predictive values for coronary MRA in detection of CA stenoses with luminal narrowing >/=50% were 88, 94, 83, and 96%, respectively. Magnetic resonance imaging in combination with MAG has proven to be a promising technique for noninvasive imaging of CA due to good image quality and a patient convenient free-breathing technique.

Adult↗

PubMedDate not supplied

Evaluation of the deep venous system in patients with suspected pulmonary embolism with multi-detector CT: a prospective study in comparison to Doppler sonography.

OBJECTIVE: This prospective study was done to evaluate the ability of indirect multidetector row CT venography (CTV) in detecting deep venous thrombosis of the pelvis and the thighs in comparison with Doppler sonography in patients with suspected pulmonary embolism (PE). METHODS: Forty-one patients with suspected PE were included, and CTV (collimation 4 x 2.5 mm, table feed 12.5 mm, 120 kV, eff. mAs 165) from the iliac crest to the knees was done after CT angiography (CTA) of the pulmonary arteries. Doppler sonography was performed within 24 hours. Applied radiation doses were estimated using the PC program WinDose. RESULTS: PE was diagnosed in 20 patients with additional DVT in 11 patients. The CTV has a sensitivity of 100%, specificity of 96.6%, a positive and negative predictive value of 91.7% and 100%, respectively. The median cumulative effective dose for CTV was 8.26 mSv with a gonadal dose of 3.87 mSv. Changing the CTV protocol to a collimation of 4 x 5 mm with a 25 mm table feed could reduce the dose by approximately 11% (p < 0.05) to 7.25 mSv and 3.35 mSv, respectively. CONCLUSION: CTV is a safe and quick diagnostic tool for detecting DVT in patients with suspected PE. Due to the relevant increase in radiation dose, the indication has to be considered very carefully.

Aged↗