C Schwenke

Publications of C Schwenke

• Contrast-enhanced magnetic resonance angiography (MRA): evaluation of three different contrast agents at two different doses (0.05 and 0.1 mmol/kg) in pigs at 1.5 Tesla.

  Authors: M Voth, Henrik J Michaely, C Schwenke, B Vos, H Pietsch

  European radiology. 02/2011; 21(2):337-44.

  To compare the image quality of contrast-enhanced magnetic resonance angiography (CE-MRA) of the supra-aortic vessels at 0.05 mmol/kg bw and 0.1 mmol/kg bw, between gadobutrol, Gd-DTPA and Gd-BOPTATo compare the image quality of contrast-enhanced magnetic resonance angiography (CE-MRA) of the supra-aortic vessels at 0.05 mmol/kg bw and 0.1 mmol/kg bw, between gadobutrol, Gd-DTPA and Gd-BOPTA quantitatively and qualitatively a total of eight pigs were evaluated intraindividually at 1.5 T. Each pig was examined using 0.1 mmol/kg gadobutrol, Gd-DTPA and Gd-BOPTA on day one and 0.05 mmol/kg on day two. MRA datasets for the carotid artery and the infraorbital artery were qualitatively assessed regarding overall image quality on an ordinal four-point scale (4-excellent, 1-non-diagnostic). The signal-to noise-ratio (SNR) was measured. The qualitative assessment of the carotid artery showed a higher median image quality for the 0.1 mmol dose than for the 0.05 mmol dose for all three compounds. No difference was found for the infraorbital artery. Mean SNR of Gd-BOPTA, Gd-DTPA, gadobutrol at 0.05 mmol/kg were 36.0 ± 13.4/37.9 ± 16.3/43.7 ± 0.4 and at 0.1 mmol/kg they were 50.1 ± 12.4/46.6 ± 6.5 / 54.6 ± 10.2. Gd-BOPTA 0.05 revealed a significantly lower SNR than all other agents at normal dose. Full-dose gadolinium MRA results in higher image quality and significantly higher SNR compared with the half dose. Gadobutrol and Gd-BOPTA have similar enhancement properties at full dose but at half dose, gadobutrol appears superior.

• "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

  European radiology. 10/2010; 21(5):1034-42.

  To evaluate the effect of the number of readers on the statistical results in peripheral MRA. 40 patients with peripheral arterial occlusive disease were included as a sample dataset in this study,To evaluate the effect of the number of readers on the statistical results in peripheral MRA. 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. 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. 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.