Page 3 of 3Pearls & pitfalls for Biliary Ultrasonography
1. Bedside ultrasound can provide you with valuable data to help you make critical diagnoses and expedite patient care. Always approach each scan with an open and inquisitive mind. You may be surprised by what you may find.
2. Always visualize the adjacent structures surrounding your target organ of interest. For example, when you seek out to evaluate the biliary system, scan through the surrounding liver parenchyma, too. Changes in the surrounding organs can alter the appearance of your target structure.
3. The gallbladder is normally dilated in disease or in the fasting state, but can be contracted soon after a meal. When the gallbladder is contracted, the walls naturally appear thicker so other sonographic signs are utilized to help make the diagnosis of cholecystitis (e.g. pericholecystic fluid, sonographic Murphy’s sign, etc.)
4. Studies have shown that systemic diseases, such as liver dysfunction or inflammation, cancer, heart failure, and renal disease can all lead to a more prominent and thickened gallbladder wall. This patient may not have acute cholecystitis, but may instead have gallbladder wall thickening secondary to the adjacent liver masses seen on bedside ultrasound.
5. When scanning through a target organ, obtain at least 4 different views of the area of interest. Use the body’s natural acoustic windows to improve your views.
6. Most right upper quadrant scans are performed with a low frequency curvilinear or phased array transducer. Become comfortable scanning with both types of probes, as each transducer has it’s own benefits and disadvantages. The curvilinear probe gives you a broader view with better resolution, whereas the phased array transducer allows you to slide the face in between rib spaces.
7. Be comprehensive with your scans. Don’t stop scanning just because you have found the answer you were looking for. Often times, interesting pathology can be discovered in the periphery of a focused scan. You may not always know exactly what you are looking at, but at least you can provide the patient with the data and knowledge to take the next best step towards improving their care.
8. Practice Makes Perfect: With bedside ultrasound, there is no substitute for experience. The more scans you do, the better you will be able to differentiate abnormal from normal, even when you may not be sure exactly what the abnormality is.
Brady Pregerson manages a free online EM Ultrasound Image Library and is the author of the Tarascon Emergency Department Quick Reference Guide. For more info visit EMResource.org.
Teresa S. Wu is the Assoc. Residency Director and Director of Ultrasound and Simulation Based Training for the Maricopa EM Program in Phoenix.