Matthias Teufel, Abstract Co-Author: Nothing to Disclose

Sabrina Koeppe MD, Abstract Co-Author: Nothing to Disclose

Andreas Boss MD, Abstract Co-Author: Nothing to Disclose

Philipp Szavay, Abstract Co-Author: Nothing to Disclose

Florian Obermayr, Abstract Co-Author: Nothing to Disclose

Claus Detlef Claussen MD, Abstract Co-Author: Nothing to Disclose

Juergen F. Schaefer MD, Presenter: Nothing to Disclose

Evaluation of an improved method of dynamic magnetic resonance urography (MRU) with short acquisition time and compensation of breathing motion for assessment of split renal function and excretion in children.

49 patients (aged between 3 months and 16 years, median 2 years) suffering from various uropathies including duplicated collecting system (n=26) and obstruction of the ureteropelvic junction (n=10) were evaluated. Precontrast images were obtained after IV administration of 15 ml/kg BW of 0.9% NaCl solution and 0.3 mg/kg furosemide 30 minutes prior to the start. A protocol for dynamic MRU was implemented over 40 minutes using a T1-weighted navigator-gated TurboFLASH sequence (TR/TE 498ms/1.2ms, saturation recovery time 300 ms, flip angle 8°) after bolus injection of 0.05 mmol/kg Gd-DTPA. The TurboFLASH sequence with its extremely TE is insensitive to changes in T2* relaxation time caused by the applied low concentrations of Gd-DTPA resulting in a linear relation between tissue contrast-medium concentration and signal-intensity (SI). 20 minutes after the Gd-DTPA bolus, an IV injection of 0.5 mg/kg of furosemide was administered. Split renal function was determined from the contrast-medium clearance using the gradients of the linear SI increase of the renal parenchyma. Decompensated obstruction was defined as a constant increase of the SI within the collecting system. Dynamic MRU was compared with MAG3 scintigraphy serving as reference standard.

In all children, images could be recorded over 40 minutes at nearly identical diaphragm position, which allowed for exact region-of-interest analysis. Excellent correlation to the MAG3 scintigraphy was demonstrated for split renal function (r= 0.96). For decompensated hydronephrosis sensitivity and specificity of MRI was 100% and 99%, respectively.

Using navigator-gated TurboFLASH sequence dynamic MRU allows for reliable assessment of renal function in children with uropathy. Lacking of breathing artefacts improved the measurements of the course of the contrast-medium concentration within parenchyma and collecting system.

Navigator-gated TurboFLASH sequence dynamic MRU allows for reliable assessment of renal function by improved measurement of the course of the contrast-medium concentration without breathing artefact.

Teufel, M, Koeppe, S, Boss, A, Szavay, P, Obermayr, F, Claussen, C, Schaefer, J, Contrast-enhanced Dynamic MR Nephrography Using TurboFLASH Navigator-gating Technique in Children  .  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9011813.html