1. Introduction To Emergency Ultrasound
Although it is possible to have renal stones without signs of obstruction, prolonged pain normally occurs with ureteral and renal pelvis dilatation. (Figure 3) Currently there are multiple ways to evaluate for the presence of renal stones.
http://www.dcmsonline.org/jax-medicine/1999journals/march99/ultrasound.htm

2. eMedicine - Nephrolithiasis: Acute Renal Colic : Article by Stephen W Leslie -- Emedicine Clinica...
Plain renal tomography is most useful when checking for small stones that might be present in the kidney before starting a preventive therapy plan or when differentiating intrarenal calcifications that are likely to be stones from extrarenal...
http://www.emedicine.com/MED/topic3437.htm

3. (c) UrologyHealth.org - Adult Conditions - Stones - Surgical Management of Stones -- Urologyheal...
Stone size, the number of stones and their location are perhaps the most important factors in deciding the appropriate treatment for a patient with kidney stones. - Surgical Management of Stones Surgical Management of Stones Normally, urine...
http://www.urologyhealth.org/adult/index.cfm?cat=12&topic=132