Premium
In vivo NMR imaging and spectroscopic investigation of renal pathology in lean and obese rat kidneys
Author(s) -
Bosch Coleen S.,
Ackerman Joseph J. H.,
Tilton Ronald G.,
Shalwitz Robert A.
Publication year - 1993
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910290309
Subject(s) - in vivo , pathology , nuclear magnetic resonance , magnetic resonance imaging , renal pathology , nuclear magnetic resonance spectroscopy , medicine , chemistry , kidney , biology , radiology , physics , microbiology and biotechnology
Abstract Diabetic nephropathy is a major cause of end‐stage renal failure. While our understanding of the pathogenesis of nephropathy is incomplete, progressive glomerular injury appears to play a significant role in the decline of renal function. Proton NMR spectroscopy and imaging techniques were used to address changes in renal pathology associated with glomerular mesangial expansion in vivo in kidneys from spontaneously obese and lean (control) littermate Zucker rats. Fully functioning rat kidneys were surgically exposed and externalized for direct NMR signal detection via a coil placed around the organ. High‐resolution (78 μm in plane) proton images were obtained at 4.7 T magnetic field strength revealing fine structure within the well‐defined cortical and medullary regions. The obese rat kidney images were distinct in appearance from the lean kidney images and exhibited marked cortical expansion as well as increased overall kidney size. Enlargement of mean glomerular diameter was verified histologically in the obese kidneys as compared with the lean kidneys. Proton T 1 and T 2 relaxation times were determined from the entire kidney using standard spectroscopic techniques, and from specific regions within the kidney from multiple T 1 and T 2 ‐weighted images. Additionally, image contrast enhancement resulting from saturation transfer between protons in restricted‐mobility environments and mobile water protons within the kidney was investigated in the lean and obese rat kidneys using magnetization‐transfer imaging techniques. At the early stage of renal injury examined in this study, diseased and healthy kidneys could not be differentiated on the basis of relaxation times alone. The magnitude of saturation transfer obtained in cortical tissue in the lean and obese kidneys was also not statistically significantly different. However, the magnitude of saturation transfer achieved in the medullary tissue of obese kidneys was statistically significantly less than that achieved in lean kidneys.