Acoustic Radiation Force Impulse Imaging for Non-Invasive Assessment of Renal Histopathology in Chronic Kidney Disease

Abstract

ObjectiveTo investigate the stiffness values obtained by acoustic radiation force impulse (ARFI) quantification in assessing renal histological fibrosis of chronic kidney disease (CKD).Methods163 patients with CKD and 32 healthy volunteers were enrolled between June 2013 and April 2014. ARFI quantification, given as shear wave velocity (SWV), was performed to measure renal parenchyma stiffness. Diagnostic performance of ARFI imaging and conventional ultrasound (US) were compared with histologic scores at renal biopsy. Intra- and inter-observer reliability of SWV measurement was analyzed.ResultsIn CKD patients, SWV measurements correlated significantly with pathological parameters (r = −0.422–−0.511, P<0.001), serum creatinine (r = −0.503, P<0.001), and glomerular filtration rate (r = 0.587, P<0.001). The mean SWV in kidneys with severely impaired (histologic score: ≥19 points) was significant lower than that mildly impaired (histologic score: ≤9 points), moderately impaired (histologic score: 10–18 points), and control groups (all P<0.001). Receiver operating characteristic (ROC) curves analyses indicated that the area under the ROC curve for the diagnosis of renal histological fibrosis using ARFI imaging was superior to these conventional US parameters. Using the optimal cut-off value of 2.65 m/s for the diagnosis of mildly impaired kidneys, 2.50 m/s for moderately impaired kidneys, and 2.33 m/s for severely impaired kidneys, the corresponding area under the ROC curves were 0.735, 0.744, and 0.895, respectively. Intra- and intre-observer agreement of SWV measurements were 0.709 (95% CI: 0.390–0.859, P<0.001) and 0.627 (95% CI: 0.233–0.818, P = 0.004), respectively.ConclusionsARFI may be an effective tool for evaluating renal histological fibrosis in CKD patients.

Point shear wave elastography (pSWE) using Acoustic Radiation Force Impulse (ARFI) imaging: a feasibility study and norm values for renal parenchymal stiffness in healthy children and adolescents

“…With regard to mean SWS values in healthy adult kidneys our results in pediatric patients show lower mean values: Hu et al reported a SWS of 2.81 m/s with a 4C1 ultrasound probe [14], whereas Bota et al found SWS values in adult kidneys with a mean of 2.49 m/s for the right and 2.36 m/s for the left kidney using a 9L4 ultrasound probe [28].…”

“…A study in adult kidneys with and without pathology revealed an inter-observer agreement assessed by ICC of 0.68 for healthy and 0.75 for pathologic kidneys [33]. Likewise, Hu et al reported a good inter-observer agreement for adult kidneys with chronic kidney disease of 0.63 [14]. A considerably lower inter-observer agreement was reported by Syversveen et al Their inter-observer variability between kidney tissues of renal allografts of adults revealed an ICC of 0.31 [35].…”

“…Guo et al reported a significant correlation of SWS and the serum creatinine, estimated glomerular filtration rate (eGFR), and urea nitrogen in CKD patients [12]. Furthermore, histological studies revealed a correlation between SWS and the pathologic degree of renal fibrosis [13,14]. pSWE might also be an effective tool in the detection of renal transplant fibrosis.…”

Value of ultrasound elastography in the diagnosis of native kidney fibrosis.

“…In the native kidney, human studies have reported various markers associated with increased kidney stiffness: estimated glomerular filtrate rate (eGFR) [23,28,29], urinary albumin / creatinine or protein / creatinine ratio [30,33], serum creatinine [23,29], urea nitrogen [23], elasticity values in healthy native kidneys [23][24][25][26][27][28][29][30][31][32][33]35], kidney biopsies [25], other imaging tests etc [24,26,35]. Thus, there are studies finding no significant correlation between markers of chronic kidney injury and elasticity of renal parenchyma in native [27] or transplanted kidney [48,51], and also studies which could not prove a significant difference of elasticity between different stages of CKD [23,25]; in addition, it has been reported an increased intra-subject variability of results in CKD versus healthy controls [33] or a higher influence of arteriosclerosis markers, such as pulsatility index or resistivity index, on kidney stiffness than eGFR [28].…”

Elastography Usage in Renal Patients

“…Transdüserin tekrarlayan kompresif hareketi sırasında hedef dokudan gelen eko sinyallerinin bozulmalarının analiz edilmesi ile doku elastisitesi ölçülmektedir (8) (17). Bu çalışmada histolojik skor ile elastisite skoru arasındaki güçlü ilişki KBY hastalarında ve diğer renal hastalarda fibrozisi belirlemede elastografinin biyopsinin yerini alabileceği düşüncesini doğurmuştur.…”