INTRODUCTORY SONOSITE HOW TO GALL BLADDER EXAM
GALL BLADDER (5MIN SONO)
GALL BLADDER FROM SONOGUIDE
Here is an excellent overview of gallbladder ultrasound from the guys at Ultrasound Leadership Academy.
Click on the link below and have a read...
Pearls and Pitfalls
1. Duodenal Air:
Because the second portion of the duodenum lies just behind the posterior wall of the gallbladder, air in the duodenum can inhibit the ability to successfully image the gallbladder. Furthermore, this “slice” of sound actually has a thickness of 1.5 mm. As it is directed towards the posterior wall of the gallbladder, some of this sound is reflected off the duodenum and the image produced is a combination of the two organs. Because air can cause shadowing, it can appear that there is a gallstone lying on the posterior wall when in reality this is air in the second portion of the duodenum (Video clip 26 and 27).
2. Renal Cyst:
The kidney is closely related to the gallbladder and cysts in the superior pole of the kidney may be confused for the gallbladder. This is one reason why it is important to view the gallbladder in both a short and long axis. The renal cyst will appear the same in both axes, while the gallbladder elongates in a long axis.
3. Ascites:
Free intraperitoneal fluid, regardless of the etiology, will appear anechoic. Be careful not to mistake ascitic fluid for pericholecystic fluid. Ascitic fluid is typically located throughout the peritoneum, including Morrison’s pouch, whereas pericholecystic fluid is localized to the anterior side of the gallbladder. Patients with ascites also have markedly thickened gallbladder walls not associated with an inflammatory process. Keep in mind that fluid that is found posterior to the gallbladder can be the result of a ruptured gallbladder.
4. WES Sign- Wall-Echo-Shadow:
When a gallbladder is contracted around a gallstone, sometimes the only visualization of this is a shadow coming out of the liver. This is due to the stone’s reflection that obscures the rest of the gallbladder. The three layers of the gallbladder wall of the anterior gallbladder are generally seen, followed by the echogenic stone which is followed by the shadow caused by the stone.
5. Patient Positioning:
Typically the images are best obtained with the patient in a supine position, although rolling the patient into a left lateral decubitus position may be helpful. This is thought to move the second portion of the duodenum away from the posterior wall of the gallbladder reducing the negative effect of duodenal air.
6. Obtain Multiple Windows:
The “X minus 7” approach refers to using an intracostal window in probes that have smaller footprints. This approach is especially useful in the morbidly obese patient. Furthermore, it is important to view the gallbladder in both the short and long axes. This can help in not mistaking the gallbladder for the IVC, renal cyst, or portal vein. In general the gallbladder will appear in a perpendicular axis to the portal vein. The “exclamation point sign” helps to draw this concept home. When the gallbladder is in the long axis (the top of the exclamation point), the portal vein is in the short axis (the point of the exclamation point).
7. Probe Orientation:
With the indicator aimed towards the patient’s head the gallbladder is generally shown in the long axis. As anatomical variation is common with the biliary system, this orientation may need to be adjusted in order to obtain this window. Keep in mind that with biliary scanning the orientation of the gallbladder is with respect to how the organ appears on the screen, not necessarily the position of the probe on the patient. The short axis of the gallbladder is typically found with the indicator towards the patient’s right