RESUMO
OBJECTIVES: Ultrasonographic scanning is currently the most widespread imaging diagnostic procedure. The method provides real-time morphological, vascular and elastographic information in a non-invasive manner. In recent years, harmonic vascular examination has become accessible using intravenous contrast agents. In urological pathology, this procedure is used in the detection and evaluation of vascular and ischemic complications, in the classification of complex cysts according to the Bosniak system, also in the renal lesions with uncertain etiology and in acute pyelonephritis for the detection of abscesses. The contrast agent (SonoVue) is angiospecific and can be used in patients transplanted immediately after surgery without adverse effects or impaired renal function. Thus, it is desirable to be used in the nephrological pathology of the renal graft and to develop diagnostic models based on the evaluation of renal microvascularization, as well as the quantitative data resulting from the graphical representation of the specific parameters. The purpose of this review is to evaluate the current state of the literature regarding the place and role of contrast substance ultrasound in the early diagnosis of acute renal graft dysfunction and to make a differential diagnosis of this pathological entity. METHOD: This review quantifies the role of contrast ultrasound in the diagnosis of acute complications of the renal graft. The research was conducted based on the databases PubMed, MedScape, Cochrane, according to the search criteria such as contrast-enhanced ultrasound + kidney transplant, "time intensity curves" + "kidney transplant", filtered for the period 2004-2018. RESULTS: In the nephrological pathology of the renal graft, contrast-enhanced ultrasound is a valuable tool, superior to Doppler ultrasound in predicting the evolution of the renal graft, identifying very small early defects in renal microvascularization. A number of studies succeeded in identifying acute graft dysfunction, some of which establish its etiology - humoral rejection versus acute tubular necrosis. On the other hand, the contrast-enhanced ultrasound parameters do not have the ability to distinguish between cellular and humoral rejection. CONCLUSIONS: If, at present, the histopathological examination is the only one that can differentiate with certainty the cause of acute renal graft dysfunction, we consider that contrast-enhanced ultrasound, as a non-invasive imaging technique, opens a favorable perspective for increasing the survival of the renal graft and decreasing the complications in the renal transplant. The combination of other ultrasound techniques, together with contrast-enhanced ultrasound, could lead to the development of new diagnostic models.
RESUMO
AIM: Our study aimed to assess the usefulness of contrast-enhanced ultrasound (CEUS) in the initial evaluation of the graft function. MATERIALS AND METHOD: A cross-sectional study was conducted in the early postoperative period on patients with kidney transplantation, between September 2017 to November 2018. Two groups of patients were investigated; delayed graft function (DGF) and early graft function (EGF). All patients were examined by grey scale, Doppler ultrasound and CEUS. RESULTS: Nineteen patients, aged from 23 to 64 years (mean age 50 years), 7 in the DGF group and 12 in the EGF group were evaluated. The resistive index (RI) show significantly higher values in the DGF group at the level of upper interlobar artery (p=0.025) and medium interlobar artery (p=0.02). The CEUS investigation shows a greater region of interest (ROI) area (p=0.02) and lower values for wash-out area under the curve (WoAUC) (p=0.047) and respectively wash-in and wash-out area under the curve (WiWoAUC) (p=0.031) for the DGF group. The quality of fit (QoF) proved lower in the DGF group either for evaluation of global graft (p=0.012), cortex (p=0.025), or medulla (p=0.009).A significant relationship among all patients was found between the glomerular filtration rate (GFR) [ml/min] and the renal artery fall time (FT) [s] (p=0.012), WoAUC [a.u.] (p=0.03), and WiWoAUC [a.u.] (p=0.024). The arterial QoF [%] was associated with the arterial ROI area (p=0.048). CONCLUSIONS: Intensity CEUS parameters WoAUC and WiWoAUC may be useful to diagnose and follow-up grafts with delayed function. Additional studies on larger cohorts are required for the recommendation of CEUS as a routine evaluation of the transplanted kidney.
