Interlobular vasculature in renal transplants: a power Doppler US study with MR correlation.

Abstract

Although PD US appears to depict the interlobular vasculature up to the renal capsule, care should be taken in the diagnosis of perfusion defects, since absence of detectable flow at the interlobular level does not always correspond to cortical areas that lack perfusion on MR images.

Power Doppler imaging and resistance index measurement in the evaluation of acute renal transplant rejection

“…One possible explanation for this result is that several cases had regional differences in vascularity within an allograft on a single power Doppler image. Although loss of far-field signals has been reported 15,16 as a result of soft tissue attenuation of the ultrasound beam, we consistently observed cases in which the near field demonstrated fewer and weaker power Doppler signals than the far field, despite appropriate setting of the transmit zone ( Figure 6). These cases posed some difficulty in assigning a single grade.…”

Technique of color Doppler quantification of vascularity in transplanted kidneys

“…9 When power Doppler visualization of the peripheral vessels in the proximal cortex was compared with MRI findings, a normal Doppler pattern was found in all but 1 of the 32 normal transplants but also in 22 (67%) of the 33 transplants that were abnormal on MRI. 10 Three of the 11 transplants with appearances suggesting perfusion defects on sonography had normal contrast enhancement on MRI. 10 A more quantitative approach to the assessment of the renal transplant microcirculation was the calculation of power Doppler histograms from 5´5 mm square sampling volumes placed over the interlobar artery, interlobular artery, and outer cortical parenchyma.…”

“…10 Three of the 11 transplants with appearances suggesting perfusion defects on sonography had normal contrast enhancement on MRI. 10 A more quantitative approach to the assessment of the renal transplant microcirculation was the calculation of power Doppler histograms from 5´5 mm square sampling volumes placed over the interlobar artery, interlobular artery, and outer cortical parenchyma. 5 Twelve patients with chronic rejection had reduced flow in the outer cortex when compared to 10 patients with normally functioning transplants, but the positions of the ROIs were arbitrary.…”

Contribution of color and power Doppler sonography to the differential diagnosis of acute and chronic rejection, and tacrolimus nephrotoxicity in renal allografts

“…The morphological changes are similar to those of cyclosporin A nephrotoxicity. According to existing reports, cyclosporin may increase the PI and RI, but results have either not reached statistical significance or have shown a wide overlap, with abnormal results found only in severe cases [3,8,19]. To our knowledge, there are no published data about Doppler sonoReferences graphic alterations in patients with tacrolimus nephrotoxicity.…”