Intravoxel incoherent motion analysis of abdominal organs: computation of reference parameters in a large cohort of C57Bl/6 mice and correlation to microvessel density.
OBJECTIVE
Diffusion-weighted magnetic resonance imaging (DW-MRI) combined with intravoxel incoherent motion (IVIM) analysis may be applied for assessment of organ lesions, diffuse parenchymal pathologies, and therapy monitoring. The aim of this study was to determine IVIM reference parameters of abdominal organs for translational research in a large cohort of C57Bl/6 laboratory mice.


METHODS
Anesthetized mice (n = 29) were measured in a 4.7 T small-animal MR scanner with a diffusion-weighted echo-planar imaging sequence at the [Formula: see text]-values 0, 13, 24, 55, 107, 260, 514, 767, 1020 s/mm(2). IVIM analysis was conducted on the liver, spleen, renal medulla and cortex, pancreas, and small bowel with computation of the true tissue diffusion coefficient [Formula: see text], the perfusion fraction [Formula: see text], and the pseudodiffusion coefficient [Formula: see text]. Microvessel density (MVD) was assessed by immunohistochemistry (IHC) against panendothelial cell antigen CD31.


RESULTS
Mean values of the different organs [[Formula: see text] (10(-3) mm(2)/s); [Formula: see text] (%); [Formula: see text] (10(-3) mm(2)/s); MVD (MV/mm(2))]: liver 1.15 ± 0.14; 14.77 ± 6.15; 50.28 ± 33.21, 2008.48 ± 419.43, spleen 0.55 ± 0.12; 9.89 ± 5.69; 24.46 ± 17.31; n.d., renal medulla 1.50 ± 0.20; 14.63 ± 4.07; 35.50 ± 18.01; 1231.88 ± 290.61, renal cortex 1.34 ± 0.18; 10.83 ± 3.70; 16.74 ± 6.74; 810.09 ± 193.50, pancreas 1.23 ± 0.22; 20.12 ± 7.46; 29.35 ± 17.82, 591.15 ± 86.25 and small bowel 1.06 ± 0.13; 16.48 ± 3.63; 15.31 ± 7.00; 420.50 ± 168.42. Unlike [Formula: see text] and [Formula: see text], [Formula: see text] correlates significantly with MVD (r = 0.90, p = 0.037).


CONCLUSIONS
This systematic evaluation of murine abdominal organs with IVIM and MVD analysis allowed to establish reference parameters for future DW-MRI translational research studies on small-animal disease models.
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. christian.eberhardt@usz.ch.
Christian
C
Eberhardt
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Moritz C
MC
Wurnig
Department of Visceral and Transplant Surgery, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Andrea
A
Wirsching
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Cristina
C
Rossi
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.|Laboratory for Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014, St. Gallen, Switzerland.
Markus
M
Rottmar
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.|Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Gloriastrasse 35, 8092, Zurich, Switzerland.
Pinar S
PS
Özbay
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Lukas
L
Filli
Swiss HPB and Transplant Center, University Hospital Zurich, Rämistrasse 100, 8091, Zurich, Switzerland.
Mickael
M
Lesurtel
Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Andreas
A
Boss
D000005:Abdomen / Q000000981:diagnostic imaging* / Q000473:pathology; D000818:Animals; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging; D017352:Echo-Planar Imaging; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007421:Intestine, Small / Q000000981:diagnostic imaging; D007668:Kidney / Q000000981:diagnostic imaging; D008099:Liver / Q000000981:diagnostic imaging; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation; D055806:Microvessels; D009038:Motion; D010179:Pancreas / Q000000981:diagnostic imaging; D010477:Perfusion; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D013154:Spleen / Q000000981:diagnostic imaging
D019408:Platelet Endothelial Cell Adhesion Molecule-1
Diffusion-weighted magnetic resonance imaging; Echo-planar imaging; IVIM; Intravoxel incoherent motion; Microvessel count; Microvessel density; Pseudodiffusion