Kidney tissue elastography and interstitial fibrosis observed in kidney biopsy

Kidney interstitial fibrosis is an important risk factor for the progression of chronic kidney disease. Kidney elastography is a noninvasive imaging modality that might be used to assess tissue fibrosis. In this study, we aimed to investigate the relationship between tissue stiffness detected in kidney elastography and interstitial fibrosis observed in kidney biopsy.

Patients who were hospitalized in a tertiary care university hospital with a kidney biopsy indication were included in this study. In all patients, the transverse and sagittal elastography measurements were made using a sonoelastography device before the biopsy. The total histological score was calculated.

Fifty-seven native kidney patients with proteinuria were included in the study. Patients were divided into two groups according to the presence (n = 6) and absence of fibrosis (n = 51) as detected by kidney biopsy. A significant correlation was found between the presence of fibrosis detected by biopsy and elastography outcomes (p = .046, r = .192). A significant correlation was found between the urea and creatinine levels and transverse elastography measurements (p = .036, r = .240). No correlation was observed between the transverse elastography measurements and total histological score consisting of glomerular, vascular, and tubular scores (r = .006, p = .967).

The findings of our study suggest a significant relationship between the elastography measurements and interstitial fibrosis. Because of the high negative predictive value (91%), we suggest that elastography should mainly be used as an exclusion test for the presence of fibrosis. We also believe that elastography may be useful to evaluate the fibrosis status in kidney diseases.