Proton Magnetic Resonance in Experimental Acute and Chronic Renal Failure in Rats

Abstract

Kidney cortical and medullary "spin-lattice" (T1) and "spin-spin" (T2) relaxation times were measured by spectroscopy in several types of experimental renal failure in rats. The T1 and the measured tissue water content were used to calculate the fraction bound (FB) and hydration fraction (HF) according to a fast proton diffusion model. The present study demonstrated the possibility to differentiate between normal and pathological renal tissue resulting from renal artery clamping (RAC), renal pedicle clamping (RPC) with or without reflow, glycerol-induced acute renal failure with or without previous dehydration, and chronic hypertensive renal failure induced by 5/6 nephrectomy and saline loading, with low (6%) or normal (21%) protein diet. Shortened T1 and prolonged T2 found in both cortex and medulla of the glycerol-induced ARF in dehydrated rats seem to represent a MR ischemic pattern. The prolongation of T1 and T2 and the increase in water content in the other groups seem to relate to different amounts of tubular obstruction and renal congestion. In summary, characteristic MR properties of different types of renal failure may provide etiological and pathogenetic diagnostic possibilities.

Assessment of renal impairment by non-contrast-enhanced conventional magnetic resonance imaging: comparison with 99mTc-DTPA renography

“…7 Imbalances in the water content between the cortex and the medulla were postulated as an explanation for the loss of the CMD on T1-weighted images of damaged kidneys. [7][8][9]11,12,[18][19][20][21][22][23] In addition to imbalances in the water content, decreased tubular fl ow or deposition of a variety of materials such as protein or blood in the medulla may result in increased signal intensity for the medulla on T1-weighted images. [9][10][11][12] For pairs of kidneys, the visual CMD on T1-weighted images provided almost perfect agreement with the renography results in this study.…”

MRI Mapping of Renal T1: Basic Concept

“…A comprehensive review of clinical T 1 (and T 2 ) applications in the kidney can be found here [24]. The use of T 1 for noninvasive assessment of renal pathology in preclinical models has already been explored in the 1980s, showing that various effects including ischemia, tubular obstruction and renal congestion may attribute to T 1 differences in rat models of acute and chronic renal failure [25,26]. T 1 values can be affected by a wide variety of changes in the tissue environment, including inflammation and fibrosis.…”