Nierenfunktionsdiagnostik mittels Magnetresonanztomographie

Abstract

Due to progress in the development of sequences and techniques magnetic resonance imaging (MRI) methods, such as functional MR urography (fMRU), arterial spin labeling (ASL), diffusion-weighted imaging (DWI), diffusion tension imaging (DTI) and blood oxygen level dependent MRI (BOLD-MRI) have become available for renal functional evaluation. In recent years research of these imaging techniques has demonstrated that they provide valid functional data with respect to renal perfusion, oxygenation and interstitial diffusion as well as glomerular filtration and the extent of an obstructive uropathy. Many pathophysiological renal processes, e. g. in transplanted kidneys, in the setting of chronic kidney disease and in the diagnostics of renal tumors, can therefore be fully evaluated. The fMRU, which enables a reliable assessment of renal function combined with high-resolution morphological evaluation of the kidneys and the entire urinary tract, has already become an inherent component in the clinical setting, at least in specialized pediatric radiology centers. To establish the new imaging methods in the clinical routine, further technical improvements and large-scale prospective clinical studies are necessary to validate the determined functional parameters, to generate standard protocols and to unify and facilitate data post-processing.

Functional MR urography in children – update 2023

“…Following the dynamic contrast-enhanced series, additional scans may be needed in the case of delayed or absent contrast excretion. In the case of absent or minimal dilation of the urinary tract, high-resolution T1-weighted 3D anatomical sequences are needed near the end of the examination in order to evaluate the exact course of the contrast-enhanced ureters [2].…”

“…"MR-Urography V5.0 Plugin for ImageJ" from Quant-IF-Labs at the University Rouen (CHU, France) [14] and "CHOP-fMRU v1.2.52" from the Childrenʼs Hospital of Philadelphia (USA) [15] are two programs for children with good agreement at least regarding relevant obstructions in comparative studies [16]. The evaluation of functional data with the semi-automate CHOP software has been performed many times and has become established [2]. This software is used as an example in the following.…”

“…Durch moderne Anwendungen wie ASL (Arterial spin labeling), BOLD-MRT (Blood oxygen level dependent) sowie DWI/DTI (diffusion weighted imaging/ diffusion tension imaging) können nichtinvasiv und ohne Einsatz von Kontrastmittel verschiedene funktionelle Parameter der Niere bestimmt werden. Insbesondere die kontrastmittelgestützte funktionelle MR-Urografie (fMRU) wird in speziellen Fällen die nuklearmedizinischen Verfahren ersetzen 2 .…”

“…Im Anschluss an die Kontrastmitteldynamik können bei verzögerter oder fehlender Kontrastmittelausscheidung weitere spätere Scans erforderlich werden. Bei fehlender oder geringer Dilatation der ableitenden Harnwege sind gegen Ende der Untersuchung anatomisch hoch aufgelöste T1-wichtende 3D-Sequenzen erforderlich, um die kontrastierten Ureteren exakt in ihrem Verlauf zu beurteilen [2].…”

“…Using modern applications like ASL (arterial spin labeling), BOLD-MRI (blood oxygen level-dependent), and DWI/DTI (diffusion-weighted imaging/ diffusion tension imaging), various functional parameters of the kidneys can be determined noninvasively and without the administration of contrast agent. In particular, contrast-enhanced functional MR urography (fMRU) replaces nuclear medicine methods in special cases [2].…”