01-01-2012 | Urogenital
Detection of intrarenal microstructural changes with supersonic shear wave elastography in rats
Published in: European Radiology | Issue 1/2012
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Objectives
To evaluate, in a rat model of glomerulosclerosis, whether ultrasonic shear wave elastography detects kidney cortex stiffness changes and predicts histopathological development of fibrosis.
Materials and methods
Three groups were studied transversally: a control group (n = 8), a group after 4 weeks of L-NAME administration (H4, n = 8), and a group after 6 weeks (H6, n = 15). A fourth group was studied longitudinally (n = 8) before, after 4 weeks and after 7 weeks of L-NAME administration. Shear modulus of renal cortex was quantified using supersonic shear imaging technique. Urine was analysed for dosage of protein/creatinine ratio. Kidneys were removed for histological quantification of fibrosis.
Results
Diseased rats showed an increased urinary protein/creatinine ratio. Cortical stiffness expressed as median (interquartile range) was 4.0 kPa (3.3–4.5) in control kidneys. It increased in all but one pathological groups: H4: 7.7 kPa (5.5–8.6) (p < 0.01); H6: 4.8 kPa (3.9–5.9) (not significant); in the longitudinal cohort, from 4.5 kPa (3.1–5.9) to 7.7 kPa (5.9–8.3) at week 4 (p < 0.05) and to 6.9 kPa (6.1–7.8) at week 7 (p < 0.05). Stiffness values were correlated with the proteinuria/creatininuria ratio (r = 0.639, p < 0.001).
Conclusions
Increased cortical stiffness is correlated with the degree of renal dysfunction. More experience in other models is necessary to understand its relationship with microstructural changes.
Key Points
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Ultrasound elastography with supersonic shear wave imaging can predict parenchymal microstructural changes
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In this rat model, cortical stiffness correlated with the proteinuria/creatininuria ratio
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Quantification of cortical stiffness could be a useful biomarker for chronic renal disease
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SSI should now be investigated in patients with native/transplanted renal disease