The ultrasonic renal exam does not require any preparation of the patient and is usually performed with the patient in the supine position. The kidneys are examined in longitudinal and transverse scan planes with the transducer placed in the flanks. When insonation of the kidney is obscured by intestinal air, the supine scan position is combined with the lateral decubitus position with the transducer moved dorsally. Preferably, the exam is initiated in the longitudinal scan plane, parallel to the long diameter of the kidney, as the kidney is easier to distinguish. In the adult patient, a curved array transducer with center frequencies of 3–6 MHz is used, while the pediatric patient should be examined with a linear array transducer with higher center frequencies. Artifacts of the lowest ribs always shadow the upper poles of the kidneys. However, the whole kidney can be examined during either normal respiration or breath hold, as the kidney will follow the diaphragm and change position accordingly.
Renal ultrasonography
Urinary tract ultrasound
Renal biopsy
Urine cytology
Computed tomography urography
Ureteroscopy
Radioisotope renography
Urine protein/creatinine ratio