Perfusion of kidney graft pyramids and cortex in contrast-enhanced ultrasonography in the determination of the cause of delayed graft function

Background:    The aim of this study was to assess the usefulness of a new ultrasound technique – contrast-enhanced ultrasound examination (US-CE) – using sulphur hexafluoride in the early post-transplant assessment of graft perfusion. Time-intensity curves (TIC) were compared with hemodynamic flow parameters (resistive index: RI) in patients with good early graft function (EGF) and acute rejection (AR) or acute tubular necrosis (ATN) as a cause of delayed graft function (DGF).
    Material/Methods:    US-CE was conducted in order to assess graft perfusion in the early period after kidney transplantation (72–120 hours) in 63 kidney allograft recipients: 35 with EGF and 28 with DGF. The DGF patients were later diagnosed based on graft biopsy as AR (n=10) or ATN (n=18). Time-intensity curves were compared with hemodynamic flow parameters typically assessed in post-operative graft diagnostics (e.g., RI).
    Results:    In the examination with US-CE in EGF patients, the regular inflow of contrast medium was demonstrated in all regions of the graft. In patients with DGF, a delay in the inflow of the contrast medium was observed, as well as significant differences in the time of inflow to the regions of interest between those 2 groups. There was a significantly longer inflow time of the contrast medium to the cortex and renal pyramids in patients with AR than in ATN recipients.
    Conclusions:    US-CE may be a valuable diagnostic tool in the determination of the cause of DGF.

Keywords: contrast-enhanced ultrasonography, kidney graft perfusion, resistive index