[Duplex Doppler study of the transplanted kidney].

Area of Science:

• Nephrology
• Radiology
• Transplant Surgery

Background:

• Renal transplant recipients require continuous monitoring for allograft dysfunction.
• Distinguishing between acute and chronic rejection is crucial for timely intervention.
• Duplex ultrasound offers non-invasive assessment of renal allograft hemodynamics.

Purpose of the Study:

• To evaluate the utility of Duplex ultrasound in diagnosing renal transplant rejection.
• To establish reference values for intrarenal vascular impedance and resistive index.
• To assess the ability of Duplex ultrasound to differentiate between acute and chronic rejection.

Main Methods:

• Duplex ultrasound (real-time sonography with pulsed Doppler) was performed on 34 renal transplant recipients.
• Morphological, structural, and hemodynamic data were collected, focusing on intrarenal vascular impedance and resistive index.
• Ultrasound findings were compared with biopsy results and clinical follow-up data.

Main Results:

• Pulsed Doppler ultrasound demonstrated utility in diagnosing renal transplant rejection.
• A resistive index threshold of 0.8 showed improved sensitivity for detecting both acute and chronic rejection compared to 0.9.
• Combined real-time and Duplex ultrasound enabled differentiation between acute and chronic rejection in most cases.
• Intrarenal impedance may increase in chronic rejection, contrary to some literature.

Conclusions:

• Duplex ultrasound is valuable for diagnosing renal transplant rejection.
• A resistive index reference value of 0.8 enhances diagnostic accuracy for rejection episodes.
• Combined ultrasound techniques improve the differential diagnosis of acute versus chronic rejection.