| In recent years, integrated backscatter(IBS) imaging technique has been proposed as a new method of ultrasonic tissue characterization. Integrating the radio frequency backscatter signal provides a potentially useful measurement for tissue characterization.Objective: To compare the IBS of renal cortex and medulla, and explore the clinical application of IBS quantifying chronic nephrosis in heterogeneity index.Methods: All the people divided into 2 groups: healthy persons and patients, were analyzed with HP 5500 sonograph. Average image intensity(AII) of renal were measured and standardized by IBS of renal sinus and expressed as IBS%. And then, we calculated the heterogeneity index of renal parenchyma.Results: (1) IBS% of renal cortex and medulla of all the patients were higher significantly than those of the control(p<0.05), but there were no significant difference of renal medulla in group②. (2) With the aggravation of renal function, the value of [cortex – medulla IBS%] had a gradual decrease in patients. However, no significant difference was found among all the people. (3) In patients with aggravation of renal function, only HI of renal parenchyma in group② were higher than those in control while the others had a gradual decrease. In group④, there was great significant difference (p<0.05).Discussion: The components of renal parenchyma ,such as glomerulus,renal tubule and renal interstitium are just good scattering sourse. Renal integrated backscatter (IBS) a noninvasive parameter of the acoustic properties of renal parenchyma can reflect pathological changes in nephrosis.It is necessary that influence of age on renal ultrasonic characters can not be neglected. Because with aging, renal will undergo serial retrogressive changes and eventually lead to the increase of IBS%. According to this, we choice all the people whose ages range from 30y to 60y to reduce selection bias and improve statistical significance.Many experimental studies have show that tubulointerstitial fibrosis can exactly forecast the aggravation of renal function, and it was more closely related to renal function and prognosis than glomerulus sclerosis. The pathologic change of tubulointerstitial can be directly used to estimate prognosis. The histological changes showed tubular atrophy and disappearance, widening of intertubular spaces with increased lymphocytes and mononuclear cells infiltration and fibrosis.In this study, with the aggravation of renal function, the value of [cortex – medulla IBS%] had a gradual decrease in chronic nephrosis. Similarly, the histological change of renal medulla is greater than that of renal cortex. To reflect the relationship between renal cortex and renal medulla, our study introduce heterogeneity index for the first time in examining chronic nephrosis which was calculated as [(renal cortex AII – renal medulla AII)/renal cortexAII] ╳100% .Examining chronic nephrosis patients, with the aggravation of renal function, only HI of renal parenchyma in early phase were higher than those in control, but in metaphase and advanced phase had a gradual decrease. Especially in advanced phase, there were great significantly decrease in HI. The fundamental cause of the change of HI lies in pathologic change, which result in the changed of microstructure, and consequently, in scattering sourses' number,size and array ect. In early phase during the impairment of renal function, glomerulus and tubulointerstitial mainly presents inflammatory, thus IBS of renal cortex increases. While in metaphase and advanced phase, tubular atrophy and disappearance, widening of interstitial spaces with increased extracellular matrix and fibrosis seem to be the key features of this final common pathway, so IBS of renal medulla increases.This study had been shown for the first time in chronic nephrosis detection that heterogeneity index is reduced in IBS imaging technique. It may produce less metrical error in heterogeneity index than in normalized IBS correspondingly. At the same time... |
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