Principles of magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) is rapidly becoming the imaging modality of choice for children. It provides high-quality anatomic, spatial, functional, and physiologic information of the kidneys and urinary tract equal and often better than other advanced imaging techniques without ionizing radiation exposure. Contrast agents allow quantitative modeling for obtaining renal and urinary collecting system quantitative functional measures important for management decision analyses in pediatric urology. In this chapter, we discuss basic principles of nuclear magnetic resonance and spectroscopy as they relate to patient preparation, image acquisition and processing, and clinical indications. Understanding these factors allows practitioners to optimize image formation of magnetic resonance urography (MRU) and better interpret static and dynamic magnetic resonance urography.