Marc Regier, Presenter: Nothing to Disclose

Claus Nolte-Ernsting MD, Abstract Co-Author: Nothing to Disclose

Gerhard B. Adam MD, Abstract Co-Author: Nothing to Disclose

Joern K. Kemper MD, Abstract Co-Author: Nothing to Disclose

To compare the image quality and anatomical depiction of the upper urinary tract using MR-urography at 1.5 and 3 Tesla in a porcine model.

Using a T1w 3D-GRE sequence (TR 5.1 ms; TE 2.3 ms; FOV 34.9 x 29.2 cm; matrix 256x179) and a high-resolution (HR) T1w 3D-GRE sequence (TR 5.4ms; TE 2.4 ms; FOV 32.9 x 29.8 cm; matrix 464x354) four healthy domestic pigs were examined at 1.5 and 3 Tesla. The MR-urographic scans were performed after intravenous injection of Gadolinium-DTPA (0.1 mmol/kg) and low-dose furosemide (0.1 mg/kg). Image evaluation was performed by two independent radiologists blinded to applied sequence parameters and field-strength. Image analysis included grading of image quality of the segmented collecting system based on a five-point-grading scale regarding the anatomical depiction and degree of artefacts observed. The signal-to-noise ratio (SNR) was determined. Statistical analysis included multi-rater-kappa and Wilcoxon test.

The mean scores for MR-urographies at 1.5 Tesla were 2.83 for the T1w 3D-GRE and 3.48 for the HR T1w 3D-GRE sequence. Significantly higher values were determined using the corresponding sequences at 3 Tesla, averaging 3.19 for the T1w 3D-GRE (p=0,047) and 3.92 for the HR T1w 3D-GRE (p=0,023) sequence. Delineation of the pelvicaliceal system was rated significantly higher at 3 Tesla compared to 1.5 Tesla (T1w 3D-GRE: p=0.015; HR T1w 3D-GRE: p=0.006). At 3 Tesla the mean SNR was 45.6 % (p=0.039) higher. A Kappa of 0.67 indicated a good correlation among the two observers.

In an experimental setup MR-urography at 3 Tesla allowed for a significantly higher image quality and SNR compared to 1.5 Tesla.

Better image quality and higher SNR at 3 Tesla might help to further improve the diagnostic impact of MR-urography compared to 1.5 Tesla.

Regier, M, Nolte-Ernsting, C, Adam, G, Kemper, J, Intraindividual Comparison of Image Quality in MR Urography at 1.5 and 3 Tesla Using an Animal Model.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5007433.html