Ultrasound is routinely used as the first imaging exam for evaluation of renal transplants and can identify most major surgical complications and evaluate vascularity with color Doppler. Ultrasound is limited, however, in the detection of parenchymal disease processes and Doppler evaluation is also prone to technical errors. Multiple new ultrasound applications have been developed and are under ongoing investigation which could add additional diagnostic capability to the routine ultrasound exam with minimal additional time, cost, and patient risk. Contrast-enhanced ultrasound (CEUS) can be used off-label in the transplant kidney, and can assist in detection of infection, trauma, and vascular complications. CEUS also can demonstrate perfusion of the transplant assessed quantitatively with generation of time–intensity curves. Future directions of CEUS include monitoring treatment response and microbubble targeted medication delivery. Elastography is an ultrasound application that can detect changes in tissue elasticity, which is useful to diagnose diffuse parenchymal disease, such as fibrosis, otherwise unrecognizable with ultrasound. Elastography has been successfully applied in other organs including the liver, thyroid, and breast; however, it is still under development for use in the transplant kidney. Unique properties of the transplant kidney including its heterogeneity, anatomic location, and other technical factors present challenges in the development of reference standard measurements. Lastly, B-flow imaging is a flow application derived from B-mode. This application can show the true lumen size of a vessel which is useful to depict vascular anatomy and bypasses some of the pitfalls of color Doppler such as demonstration of slow flow.
This is a preview of subscription content, log in to check access.
Compliance with ethical standards
Conflict of interest
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
The institutional review board waived informed consent for all individual participants included in the study.
Quaia E, Bertolotto M, Cioffi V, et al. (2008) Comparison of contrast-enhanced sonography with unenhanced sonography and contrast-enhanced CT in the diagnosis of malignancy in complex cystic renal masses. AJR Am J Roentgenol 191(4):1239–1249CrossRefPubMedGoogle Scholar
Wei SP, Xu CL, Zhang Q, et al. (2017) Contrast-enhanced ultrasound for differentiating benign from malignant solid small renal masses: comparison with contrast-enhanced CT. Abdom Radiol 42(8):2135–2145CrossRefGoogle Scholar
King KG, Gulati M, Malhi H, et al. (2015) Quantitative assessment of solid renal masses by contrast-enhanced ultrasound with time-intensity curves: how we do it. Abdom Imaging 40(7):2461–2471CrossRefPubMedGoogle Scholar
Stenberg B, Wilkinson M, Elliott S, et al. (2017) The prevalence and significance of renal perfusion defects in early kidney transplants quantified using 3D contrast enhanced ultrasound (CEUS). Eur Radiol 27(11):4525–4531CrossRefPubMedGoogle Scholar
Alvarez Rodriguez S, Hevia Palacios V, Sanz Mayayo E, et al. (2017) The usefulness of contrast-enhanced ultrasound in the assessment of early kidney transplant function and complications. Diagnostics 7(3):53CrossRefPubMedCentralGoogle Scholar
Benozzi L, Cappelli G, Granito M, et al. (2009) Contrast-enhanced sonography in early kidney graft dysfunction. Transplant Proc 41(4):1214–1215CrossRefPubMedGoogle Scholar
Kihm LP, Hinkel UP, Michael K, et al. (2009) Contrast enhanced sonography shows superior microvascular renal allograft perfusion in patients switched from cyclosporine A to everolimus. Transplantation 88(2):261–265CrossRefPubMedGoogle Scholar
Pan FS, Liu M, Luo J, et al. (2017) Transplant renal artery stenosis: evaluation with contrast-enhanced ultrasound. Eur J Radiol 90:42–49CrossRefPubMedGoogle Scholar
Grzelak P, Kurnatowska I, Nowicki M, et al. (2013) Detection of transplant renal artery stenosis in the early postoperative period with analysis of parenchymal perfusion with ultrasound contrast agent. Ann Transplant 18:187–194CrossRefPubMedGoogle Scholar
Chi T, Usawachintachit M, Weinstein S, et al. (2017) Contrast enhanced ultrasound as a radiation-free alternative to fluoroscopic nephrostogram for evaluating ureteral patency. J Urol 198(6):1367–1373CrossRefPubMedGoogle Scholar
Shen C, Zhang B, Han WK, et al. (2017) Percutaneous renal access for percutaneous nephrolithotomy guided by contrast enhanced ultrasound: a single-center preliminary experience in China. Beijing Da Xue Xue Bao Yi Xue Ban 49(6):1071–1075PubMedGoogle Scholar
Hull TD, Agarwal A, Hoyt K (2017) New ultrasound techniques promise further advances in AKI and CKD. J Am Soc Nephrol 28(12):3452–3460CrossRefPubMedGoogle Scholar
Wang Z, Yang H, Suo C, et al. (2017) Application of ultrasound elastography for chronic allograft dysfunction in kidney transplantation. J Ultrasound Med 36(9):1759–1769CrossRefPubMedGoogle Scholar
Early H, Aguilera J, McGahan J, et al. (2017) Challenges and considerations when using shear wave elastography to evaluate the transplanted kidney with pictorial review. J Ultrasound Med 36(9):1771–1782CrossRefPubMedGoogle Scholar
Nakao T, Ushigome H, Nakamura T, et al. (2015) Evaluation of renal allograft fibrosis by transient elastography (fibro scan). Transplant Proc 47(3):640–643CrossRefPubMedGoogle Scholar
Yoo MG, Jung DC, Oh YT, et al. (2017) Usefulness of multiparametric ultrasound for evaluating structural abnormality of transplanted kidney: can we predict histologic abnormality on renal biopsy in advance? AJR Am J Roentgenol 209(3):W139–W144CrossRefPubMedGoogle Scholar
Wachsberg RH (2003) B-flow, a non-Doppler technology for flow mapping: early experience in the abdomen. Ultrasound Q 19(3):114–122CrossRefPubMedGoogle Scholar
Bucek RA, Reiter M, Koppensteiner I, et al. (2002) B-flow evaluation of carotid arterial stenosis: initial experience. Radiology 225(1):295–299CrossRefPubMedGoogle Scholar
Tola M, Yurdakul M, Ozbulbul NI (2012) B-flow imaging for the measurement of residual lumen diameter of renal artery stenosis. J Clin Ultrasound 40(2):85–90CrossRefPubMedGoogle Scholar
Wachsberg RH (2007) B-flow imaging of the hepatic vasculature: correlation with color Doppler sonography. AJR Am J Roentgenol 188(6):W522–W533CrossRefPubMedGoogle Scholar
Clevert DA, Johnson T, Jung EM, et al. (2007) Color Doppler, power Doppler and B-flow ultrasound in the assessment of ICA stenosis: comparison with 64-MD-CT angiography. Eur Radiol 17(8):2149–2159CrossRefPubMedGoogle Scholar
Yurdakul M, Tola M, Cumhur T (2004) B-flow imaging of internal carotid artery stenosis: comparison with power Doppler imaging and digital subtraction angiography. J Clin Ultrasound 32(5):243–248CrossRefPubMedGoogle Scholar
Russo E, Cerbone V, Sciano D, et al. (2010) Posttransplant renal monitoring with B-flow ultrasonography. Transplant Proc 42(4):1127–1129CrossRefPubMedGoogle Scholar
Clevert DA, Kubisch C, Weckbach S, et al. (2010) B-flow and color Doppler sonography findings in iatrogenic carotid-jugular arteriovenous fistula. Clin Hemorheol Microcirc 44(1):19–25PubMedGoogle Scholar