P0715
SUPERB MICROVASCULAR IMAGING: AN INNOVATIVE ULTRASOUND TECHNIQUE FOR EARLY DETECTION OF KIDNEY DYSFUNCTION AND RENAL FIBROSIS

Superb microvascular imaging (SMI) is an innovative ultrasound image processing technique that shows greater details and better visualization of small branching vessels by using a unique algorithm that offer high frame rates, less clutter, and fewer tissue motion artefact that were not previously possible without the use of contrast agent. We assume that SMI provides superb information regarding the severity of chronic kidney disease (CKD) and associated the fibrotic changes. Therefore, the present study was designed to examine whether SMI can detect early renal fibrosis as compared with the reference standard renal biopsy.

The SMI was performed in patients (n=47) with CKD stage 2-4, where some of them underwent biopsy proven chronic renal dysfunction and fibrosis as part of the diagnosis and therapeutic judgment as needed. In addition, biochemical tests were performed in order to obtain the serum parameters of kidney function (BUN, Serum Creatinine), a urine collection test for the assessment of proteinuria, and estimation of GFR by MDRD formula in patients with CKD of various severity and healthy controls (n=17). In addition, all patients underwent SMI US imaging, where vascularity is expressed as SMI index (low index reflects low vascularity/fibrosis and vice versa).

As expected, SMI vascular index was significantly lower in CKD patients as compared with healthy control (72.2±3.1 Vs 49.1±2.6 %, P<0.001). Interestingly, strong correlation between the SMI index and eGFR was found among the CKD patients (r=0.595, P<0.001). Similarly, a keen correlation was found between the SCr and SMI index of the diseased subjects. Among those who underwent renal biopsy, SMI index corresponds with the histological alterations as well as CKD staging.

This study demonstrates that in patients with CKD of various stages, SMI imaging may be utilized as a simple and practical method for evaluation of the chronic renal morphological changes and for the differentiation between CKD grades.