II. Indications
-
Urolithiasis (considered primary evaluation in Europe)
- Consider in combination with Abdominal XRay
- Consider repeating Bedside Ultrasound after intravenous hydration
- Pregnant patient and Children
- Cholecystitis suspected
- Gynecologic process suspected
III. Efficacy
- Compares favorably to IVP and CT Abdomen
- Ultrasound is a safe evaluation tool for Ureterolithiasis without significant missed serious conditions
IV. Findings
- Hydronephrosis
- Renal Stones
- Absent unilateral ureteral jet flow into Bladder
V. Imaging
- Transducer
- Curved Linear Array Probe (2-5 MHz)
- Position probe in lateral Abdomen, upper quadrant on each side
- Precautions
- Left Kidney is more difficult to image due to higher lying Kidney and overlying gas in LUQ
- Consider positioning probe in a more lateral, mid-axillary position
- Have patient take a deep breath to bring Kidney down into window
- Dehydration decreases Test Sensitivity
- Hydronephrosis and ureteral jets are more difficult to detect in Dehydration
- Consider repeat Ultrasound after intravenous hydration
- Renal pyramids may appear similar to Hydronephrosis (especially in a hydrated patient)
- However, renal pyramids are limited to the cortex
- Left Kidney is more difficult to image due to higher lying Kidney and overlying gas in LUQ
- View: Each Kidney
- Longitudinal Plane (long axis with indicator at 12:00)
- Transverse Plane (short axis with indicator at 9:00)
- Hydronephrosis findings
- Calyces will be gradually more distorted as Hydronephrosis progresses from mild to severe
- Imagine a slowly appearing hand print.
- Mild Hydronephrosis
- Finger tips (black, anechoic calyces) are visible
- Moderate to severe Hydronephrosis
- Chubby fingers appear as well as the palm (central black, anechoic renal Pelvis)
- Mild Hydronephrosis
- Proximal ureter is dilated but renal architecture is preserved
- Divides the major calyces
- Moderate Hydronephrosis
- Calyces enlarge (central anechoic renal Pelvis with stubby projections towards renal cortex)
- Divides the minor calyces
- Severe Hydronephrosis
- Calyces enlarge and coalesce into one large anechoic region with loss of papillae
- Cortex is compressed
- Calyces will be gradually more distorted as Hydronephrosis progresses from mild to severe
- Renal Calculi
- Stones are best identified on Ultrasound at the ureterovesical junction (UVJ)
- Hyperechoic stone-like lesions with posterior "clean" shadowing (similar to Gallstones)
- Shadow size correlates with stone size
- Stones will glitter from reverberation artifact when color doppler is applied
- View: Bladder
- Longitudinal Plane (long axis with indicator at 12:00)
- Transverse Plane (short axis with indicator at 9:00)
- Obtain view of trigone with doppler to demonstrate bilateral ureteral jets
- Presence of bilateral ureteral jets in a well hydrated patient excludes ureteral obstruction
VI. References
- Mateer and Jorgensen (2012) Introduction and Advanced Emergency Medicine Ultrasound Conference, GulfCoast Ultrasound, St. Pete's Beach
- Noble (2011) Emergency and Critical CareUltrasound, Cambridge University Press, New York, p. 227-39
- Reardon (2011) Pocket Atlas Emergency Ultrasound, McGraw Hill, New York, p. 163-88