Daily Archives: June 20, 2019

Thickened gall bladder wall: not always acute cholecystitis

In clinical practice, a cut off of 3mm is commonly used to define the upper limit of normal gall bladder wall thickness and acute cholecystitis is one thing that comes to our mind when we see increased wall thickness. Along with a compatible clinical picture, ultrasonographic features that suggest acute cholecystitis are a distended gallbladder, thickened walls, biliary sludge and lithiasis, pericholecystic fluid and the sonographic Murphy’s sign, which is defined as maximal abdominal tenderness from pressure of the ultrasound probe over the visualized gallbladder.

However, this is not the only condition that causes gall bladder wall thickening. As POCUS is not necessarily performed in a fasting patient, we must be aware that the gall bladder wall is thick in non-fasting state. In addition, any systemic disease associated with generalized hypervolemia such as congestive heart failure can lead to gall bladder wall thickening. In these patients, think of alternate etiology if the clinical picture does not fit. The presence of gall stones also does not mean much if there are no symptoms. Following image shows thickened gall bladder wall and ascites in a patient with congestive heart failure exacerbation. Note that the liver floating in ascites appears like a fish with gall bladder as its mouth. Though the wall diameter is measured in transverse plane in this example, it is generally recommended to be measured in long axis, and of the anterior wall (the one on the top).

Renal cyst: simple or complex?

The diagnosis of a simple benign renal cyst on ultrasound requires the presence of all the following findings: a well-defined, roundish, anechoic structure, imperceptible near wall and thin echogenic far wall, and increased through transmission manifested by acoustic enhancement. Acoustic enhancement refers to the hyperechoic or bright area relative to surrounding tissues, distal to structures that are excellent transmitters of sound waves. This artefact is not restricted to cysts and can be seen with any fluid containing space such as a blood vessel or urinary bladder. Any lesion that does not meet criteria for a simple cyst is considered a complex cyst and may be characterized by findings such as irregular thickened walls, septations, internal echoes, and calcifications.

What is the utility of sonography in Bosniak classification of cysts?

The Bosniak classification system helps in the diagnosis and management of renal cysts. As the detection of neovascularization in malignant lesions, indicated by contrast enhancement (on CT) of solid components, septa or walls, is an essential part of the classification, ultrasound cannot be used instead of CT. However, it is known that ultrasound may demonstrate internal septa better than CT and MRI. Therefore, it has been suggested that simple and minimally complex (Bosniak I and II) cysts may be followed with sonography alone.

Bosniak classification illustration: Case courtesy of Dr Matt Skalski, Radiopaedia.org, rID: 20989