CT of the abdomen and pelvis without contrast performed using low-radiation-dose scanning protocols is the preferred exam for most adults with suspected nephrolithiasis. If low-dose CT scan technology is not available, standard-dose abdominopelvic CT or ultrasound of the kidneys and bladder are the two second-line options for initial imaging. The choice between standard-dose CT and ultrasound is determined by considerations of diagnostic accuracy, cumulative radiation dose over time, and the need for treatment planning information should the exam prove positive. Other available, but less frequently used, modalities for evaluating patients with suspected nephrolithiasis include abdominopelvic radiography, intravenous pyelography (IVP), and magnetic resonance imaging (MRI) of the abdomen and pelvis
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