Multimodal ultrasound in renal transplantation: a pictorial essay on graft complications

Kidney transplantation is the preferred treatment for eligible patients with end-stage kidney disease, but long-term graft survival requires timely recognition of early and late complications. Ultrasound is the first-line imaging modality for renal allograft evaluation because it is safe, repeatable, radiation-free and suitable for bedside assessment. A multimodal ultrasound strategy, combining B-mode imaging, color and spectral Doppler ultrasound, contrast-enhanced ultrasound and shear wave elastography, provides complementary information on graft morphology, vascular integrity, microperfusion and tissue stiffness. Conventional ultrasound and Doppler remain the diagnostic backbone, while contrast-enhanced ultrasound and elastography may improve diagnostic confidence in selected scenarios, especially when standard findings are inconclusive. This pictorial essay offers a practical, image-based overview of multimodal ultrasound in renal allograft complications, highlighting key imaging patterns, clinical applications and limitations.