Renal transplant assessment with color and pulsed ultrasonography. 1st part: surgical complications

Color duplex Doppler ultrasound (US) is a highly important technique in kidney transplantation (Tx). We have performed 304 serial explorations in 140 transplant recipients assessing the morphological aspect of the graft, possible dilatation of the urinary tract and collections. Subsequently, we used color and pulsed Doppler to study the renal vascular permeability and the parenchymal resistance, calculating the indices of resistance (RI) and systolic acceleration and the frequencies. We have compared these findings with those observed in a control group of 45 patients with normally functioning grafts and we have also compared them according to the different pathologies, with those of other diagnostic imaging techniques to identify the present role of each in the assessment of kidney transplantation. Plain US plays an important role in the detection of dilations and peri renal collections, and Doppler makes it possible to differentiate, in some cases, obstructive from non obstructive dilatation. The US features of collections are nonspecific. In pulsed Doppler US, the lymphocytes present slightly elevated RI, higher than those produced in secondary dilation, in abscess-related processes and in sub capsular collections with parenchymal compromise. Color duplex Doppler is of greatest use in the diagnosis of vascular complications of Tx, especially thrombosis, stenosis and A-V fistulas. (Author)