**1. Introduction**

At the end-stage of renal failure, the best option for treatment is kidney transplantation, before starting any form of dialysis. The scarcity of organs from cadaveric donors and the comorbidity of the receptors patients, delay this treatment from being routinely performed prior to dialysis. Living-donor kidney transplantation can meet this objective perfectly, since it does not depend on waiting lists imposed by cadaveric donation [1]. In recent years, the expansion of genetically unrelated living donation has facilitated living-donor kidney transplantation as spouses, distant relatives, and even good friends have increased the pool of potential living donors. The living-donor transplants offer better survival than those of cadaveric-donor transplants, despite of HLA compatibility [2, 3].

For cadaver's donors, cause of brain death, age, plasma levels of creatinine and hemodynamic stability are the main factors for evaluating a potential donor. In contradistinction, the imaging methods constitute the initial assessment of the living donor in the kidney transplantation, with special attention to the kidneys (size, structure, lithiasis, arterial blood flow) and pelvis anatomy. The abdominal Color Doppler ultrasound, computed tomography (CT), selective kidney arteriography and Magnetic Ressonance (MR) with three-dimensional reconstruction and excretory phase study provide an anatomical assessment of the arterial vascularization (identification of the main artery, accessory or aberrant arteries or early divisions) of the venous system (number, situation, size and anatomic abnormalities) and the kidney parenchyma with the variations of collecting duct system, helping to choose the most appropriate organ to be removed [4, 5].

© 2013 Muglia et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In the postoperative phase, many kinds of images methods (ultrasound, scintigraphy, CT and MR) may help in early diagnosis of complications, as described below. In this chapter we review the usual image evaluation techniques in kidney transplantation.

contrast. CT will play a major role for evaluation potential donors for living transplantation

Imaging in Kidney Transplantation http://dx.doi.org/10.5772/55074 27

Digital Subtraction Angiography (DSA) was commonly used to investigate vascular compli‐ cations, e.g. renal artery transplant stenosis, suspected by US and is still considered the gold standard for such diagnoses [7, 21]. However, nowadays, with the possibility of using noninvasive methods with high accuracy for diagnosing vascular complications, such as MR angiography, DSA is practically reserved for therapeutic purposes only. The ability to guide minimally invasive procedures, as angioplasty and stenting of vascular stenosis makes DSA the ideal method to assess post-transplant patients avoiding more aggressive surgical proce‐

Functional imaging methods based on nuclear medicine, such as the dynamic renal study which use glomerular filtration agents and tubular secretion agents, are useful and routinely used tools for evaluation of renal transplants. Glomerular agents (99mTc-DTPA) are considered to be ideal ones, since glomerular filtration is defined as the main reflex of renal function and their mechanism of extraction occur through the process of ultrafiltration driven by Starling forces in the glomeruli. The most important regulatory mechanisms in glomerular filtration are renal blood flow and the peripheral vascular resistance of afferent and efferent glomerular arterioles. The normal distribution of these renal agents is intravascular, and they are elimi‐

as will be described later on in this chapter [20].

**2.4. Digital Subtraction Angiography**

**3. Radionuclides imaging**

**Figure 1.** DTPA renal scintigraphy. Phase of preserved arterial blood flow.

dures [21].
