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Open Access 01-05-2011 | Vascular-Interventional

“Number needed to read”—How to facilitate clinical trials in MR-angiography

Authors: M. Voth, U. I. Attenberger, A. Luckscheiter, S. Haneder, T. Henzler, S. O. Schoenberg, C. Schwenke, H. J. Michaely

Published in: European Radiology | Issue 5/2011

Abstract

Purpose

To evaluate the effect of the number of readers on the statistical results in peripheral MRA.

Materials and methods

40 patients with peripheral arterial occlusive disease were included as a sample dataset in this study, randomly separated into two matched groups with n = 20 patients (group 1—gadobutrol, group 2—gadoterate meglumine) who underwent a continuous table movement MRA of the peripheral vessels at 3 T. Image quality (IQ) of 17 vessel segments was evaluated by 5 independent readers. The effect of the number of readers on significance and statistical power was statistically analyzed.

Results

Image quality in group 1 (gadobutrol) ranks significantly higher compared to group 2 (gadoterade meglumine) with a diagnostic IQ in 97% vs. 78% (p < 0.0001). For the diagnostic/non-diagnostic IQ assessment significance was reached with one reader 1/5 times (20%), with two readers in 4/10 (40%), with three readers in 6/10 (60%), with four readers in 4/5 (80%), with five readers in 1/1 (100%). Power considerations showed considerable gain when increasing the number of readers.

Conclusion

Increasing the number of readers in a diagnostic MRA-study can be used to achieve a higher power or to decrease the number of subjects included with maintained statistical validity.

Food and Drug Administration (FDA) (2004) Developing medical imaging drugs and biological products. Part 3: Design, Analysis, and interpretation of clinical studies. Available via Food and Drug Administration, http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm071604.pdf, Accessed 30 Aug 2010

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Title: “Number needed to read”—How to facilitate clinical trials in MR-angiography
Authors: M. Voth
U. I. Attenberger
A. Luckscheiter
S. Haneder
T. Henzler
S. O. Schoenberg
C. Schwenke
H. J. Michaely
Publication date: 01-05-2011
Publisher: Springer-Verlag
Published in: European Radiology / Issue 5/2011
Print ISSN: 0938-7994
Electronic ISSN: 1432-1084
DOI: https://doi.org/10.1007/s00330-010-1993-2

Keynote webinar | Spotlight on medication adherence

Springer Medicine

“Number needed to read”—How to facilitate clinical trials in MR-angiography

Abstract

Purpose

Materials and methods

Results

Conclusion

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

Purpose

Materials and methods

Results

Conclusion

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