The qualitative and quantitative assessment of the renal cortex of the clinically healthy rabbits

Abstract

Qualitative ultrasonographic images in diagnosing renal parenchymal diseases can be inadequate. The relationship between renal cortical echogenicity and parenchymal disease has been demonstrated in people. However, it is difficult to determine diffuse fat vacuoles and the parenchymal diseases at qualitative renal assessment. Disorders of the renal cortex are frequently seen in rabbits. The aim of this study was to qualitatively and quantitatively evaluate the echogenicity of the renal cortex in clinically healthy rabbits. Fourty-two clinically normal and with no history of renal disease rabbits were used. The each rabbit was investigated by complete blood count, urinalysis and renal biopsy. Renal ultrasonography was performed with a 6.5 MHz probe. For each image, three equally sized regions of interest was detected within the renal cortex. The mean pixel intensity was determined using an 8-bit grayscale, with 256 colour of grey colours. Qualitative echogenicity was evaluated by two observers. Observer 1 evaluated as an isoechoic (36/42) and hyperechoic (6/42). Observer 2 evaluated as an isoechoic (35/42) and hyperechoic (7/42). Quantitatively, the mean pixel intensities analysed for the renal cortex was 59.2±2.23 (range: 28-91). The result of this study indicates that analysis of digitized renal cortical ultrasonographic images from rabbits using the histogram technique can be used to quantitatively determine echogenicity. 

Keywords

• Echogenicity,histogram,mean pixel intensity,rabbit,ren

References

1. 1. Aktan S (2004): Digital Image Analysis in Livestock. 160-165. In: Proocedings of 4th National Livestock Science Congress, Isparta, Turkey.
2. 2. Alm-Eldeen A, Tousson E (2012): Deterioration of glomerular endothelial surface layer and the alteration in the renal function after a growth promoter boldenone injection in rabbits. Hum Exp Toxicol, 31, 465-472.
3. 3. Chi T, Feldstein VA, Nguyen HT (2006): Increased echogenicity as a predictor of poor renal function in children with grade 3 to 4 hydronephrosis. J Urol, 175, 1898–1901.
4. 4. Demir A, Türker P, Bozkurt SU, et al (2015): The histomorphological findings of kidneys after application of high dose and high-energy shock wave lithotripsy. Cent European J Urol, 68, 72-78.
5. 5. Dimitrov RS (2012): Ultrasound features of kidneys in the rabbit (Oryctolagus Cuniculus). Vet World, 5, 274-278.
6. 6. Drost WT, Henry GA, Meinkoth JH, et al (2000): Quantification of hepatic and renal cortical echogenicity in clinically normal cats. Am J Vet Res, 61, 1016-1020.
7. 7. Ivancić M, Mai W (2008): Qualitative and quantitative comparison of renal vs. hepatic ultrasonographic intensity in healthy dogs. Vet Radiol Ultrasound, 49, 368-373.
8. 8. Lamont AC, Pelmore JM, Thompson JR, et al (1995): Ultrasound assessment of liver and kidney brightness in infants. Use of the gray-level histogram. Invest Radiol, 30, 232–238.

9. 9. Liu P, Gao YH, Tan KB, et al (2004): Grey scale enhancement of rabbit liver and kidney by intravenous injection of a new lipid-coated ultrasound contrast agent. World J Gastroenterol, 10, 2369-2372.
10. 10. Manley JA, O'Neill WC (2001): How echogenic is echogenic? Quantitative acoustics of the renal cortex. Am J Kidney Dis, 37, 706-711.
11. 11. Maurya H, Kumar T, Kumar S, et al (2018): Anatomical and physiological similarities of kidney in different experimental animals used for basic studies. J Clin Exp Nephrol, 3, 1-6.
12. 12. Marian AJ, Yun W, Do-Sun Lim, et al (1999): A transgenic rabbit model for human hypertrophic cardiomyopathy. J Clin Invest, 104, 1683–1692.
13. 13. Moghazi S, Jones E, Schroepple J, et al (2005): Correlation of renal histopathology with sonographic findings. Kidney Int, 67, 1515-20.
14. 14. Nakamura K, Sasaki N, Yoshikawa M, et al (2009): Quantitative contrast-enhanced ultrasonography of canine spleen. Vet Radiol Ultrasound, 50, 104-108.
15. 15. Newell SM, Selcer BA, Girard E, et al (1998): Correlations between ultrosonographic findings and specific hepatic diseases in cats: 72 cases (1985–1997). J Am Vet Med Assoc, 213, 94–98.
16. 16. Quesenberry K, Carpenter C (2012): Disorders of the Reproductive and Urinary Systems. 217-231. In: E Klapheke, J Paul-Murphy (Eds), Ferrets, Rabbits, and Rodents. Elsevier Press, USA.
17. 17. Redrobe S (2013): Ultrasonography. 190-211. In: F Harcourt-Brown, J Chitty (Eds), Rabbit Surgery, Dentistry and Imaging. British Small Animal Veterinary Association, England.
18. 18. Rivers BJ, Walter PA, Holm JC, et al (1996): Gray-scale sonographic characterization of aminoglycoside-induced nephrotoxicosis in a canine model. Invest Radiol, 31, 639–651.
19. 19. Smith-Levitin M, Blickstein I, Albrect-Shach AA et al (1997): Quantitative assessment of gray-level perception: observers’ accuracy is dependent on density differences. Ultrasound Obstet Gynecol, 10, 346–349.
20. 20. Nyland TG, Mattoon JS, Wisner ER (1995): Physical Principles, Instrumentation, and Safety of Diagnostic Ultrasound. 3-18. In: TG Nyland, JS Mattoon (Eds), Veterinary Diagnostic Ultrasound. WB Saunders Co, Philadelphia.
21. 21. Robinson DE, Gill RW, Kossoff G (1986): Quantitative sonography. Ultrasound Med Biol, 12, 555–565.
22. 22. Song CY, Kim BC, Hong HK, et al (2007): TGF-beta type II receptor deficiency prevents renal injury via decrease in ERK activity in crescentic glomerulonephritis. Kidney Int, 71, 882-888.
23. 23. Walter PA, Johnston GR, Feeney DA et al (1988): Applications of ultrasonography in the diagnosis of parenchymal kidney disease in cats: 24 cases (1981-1986). J Am Vet Med Assoc, 192, 92-98.
24. 24. Yabuki A, Endo Y, Sakamoto H, et al (2008): Quantitative assessment of renal cortical echogenicity in clinically normal cats. Anat Histol Embryol, 37, 383-386.
25. 25. Yeager AE, Anderson WI (1989): Study of association between histologic features and echogenicity of architecturally normal cat kidneys. Am J Vet Res, 50, 860-863.