Renal parenchyma impairment characterization in partial unilateral ureteral obstruction in mice with intravoxel incoherent motion‐MRI

Abstract

Ureteropelvic junction obstruction constitutes a major cause of progressive pediatric renal disease. The biological mechanisms underlying the renal response to obstruction can be investigated using a clinically relevant mouse model of partial unilateral ureteral obstruction (pUUO). Renal function and kidney morphology data can be evaluated using renal ultrasound, scintigraphy and uro-magnetic resonance imaging (uro-MRI), but these methods are poorly linked to histological change and not all are quantitative. Here, we propose to investigate pUUO for the first time using an intravoxel incoherent motion diffusion sequence. The aim of this study was to quantitatively characterize impairment of the kidney parenchyma in the pUUO model. This quantitative MRI method was able to assess the perfusion and microstructure of the kidney without requiring the injection of a contrast agent. The results suggest that a perfusion fraction (f) reduction is associated with a decrease in the volume of the renal parenchyma, which could be related to decreased renal vascularization. The latter may occur before impairment by fibrosis and the findings are in accordance with the literature using the UUO mice model and, more specifically, on pUUO. Further investigation is required before this technique can be made available for the diagnosis and management of children with antenatal hydronephrosis and to select the optimal timing of surgery if required.

Intravoxel incoherent motion diffusion-weighted imaging and shear wave elastography for evaluating peritumoral liver fibrosis after transarterial chemoembolization in a VX2 rabbit liver tumor model

“…During the MRI scanning process, this study used free breathing mode for image acquisition, and motion artifacts inevitably exist in this study. This is consistent with what has been mentioned in previous related animal-level studies (Pons et al, 2018), and there is no better way to avoid motion artifacts at the animal level. In addition, VX2 liver tumor was inoculated in the background of normal liver, and then the liver cancer was treated with TACE, and liver fibrosis finally occurred after TACE treatment.…”

“…Previous research shown that vascular flow play important role in diffusion-weighted imaging contrast ( Sigmund et al, 2012 ), which means that this study may be biased due to perfusion factors, which require us follow-up further research. Finally, b values selected in this study was similar with the research’s at pons et al (2018) , and there is a slight difference within the b value less than 200. This is because there are no uniform IVIM parameters and quantitative parameters may further improve using abdominal IVIM analysis in animal studies.…”

Reduced respiratory motion artefact in constant TR multi-slice MRI of the mouse

“…Furthermore, unpredictable events such as periodic double breaths result in unavoidable corruption of data. In instances where a respiratory triggered approach is considered too inefficient, motion artefacts have been reduced with signal averaging [12]. A variable TR also confounds the quantification of metrics derived from magnetisation preparation schemes such as MT and CEST.…”

Acute renal impairment characterization using diffusion magnetic resonance imaging: Validation by histology

“…13 IVIM demonstrated excellent corticomedullary differentiation. 12,14 Earlier studies indicated that IVIM parameters were sensitive to chronic renal impairment, such as the grade of clear cell renal cell carcinoma, 15 diabetic kidney, 16,17 ureteral obstruction [18][19][20][21] and renal artery stenosis. 22 The decrease in renal cortical perfusion can explain the alteration in magnetic resonance parameters when renal function changes.…”