Water Bath Technique
February 2024
Author: Justine Ko, MD, CAQ-SM
Peer Reviewer: R. Conner Dixon, MD, CAQ-SM
This image was obtained using a linear probe along the dorsal longitudinal aspect of the 5th metacarpal and proximal phalanx through 2-3cm of water in a basin.
Image 1: Author’s own image.
Image 2: Demonstration of the ultrasound technique for this case. Author’s own image.
Can you name the key structures/layers in this dorsal longitudinal image of the 5th metacarpal phalangeal (MCP) joint using a water bath technique?
Below are the major structures of interest labeled in this dorsal longitudinal MCP ultrasound image.
Image 2: Author’s own images, author’s own annotations
A 37 year old male is complaining of left hand pain after he got a wooden splinter in it 3 months ago. You obtain an ultrasound image of the area using a water bath technique with the findings below. What is your diagnosis? Can you identify the structures?
Image 1: Case courtesy of Maulik S Patel, Radiopaedia.org, rID: 61792
Image 2: Demonstration of the ultrasound technique for this case. Author’s own image.
Can you identify the structures?
Image 3: Case courtesy of Maulik S Patel, Radiopaedia.org, rID: 61792, Author’s own annotations
What is the benefit of a water bath technique?
The water bath technique gives a liquid medium to conduct the ultrasound through and eliminates the need for gel. This is particularly useful for small anatomical areas such as fingers or when sharp angles in anatomy make continuous contact with the surface difficult. The water fills all spaces eliminating air pockets that can obscure the view. The water bath technique typically produces superior images when compared to gel and direct contact on the same area. See below for a comparison view of our normal images from the first week. The image on the left is the water bath technique, the image on the right is the same view but using gel directly on the area of interest.
Image 4: Left image with water bath technique, R image with gel