Dear OCAD-
I’m seeking guidance, recommendations, or other observations regarding rapid KV-switching single-source DECT for gout imaging. We have a GE Revolution Apex rapid KV-switching DECT at our institution and have started doing gout imaging. However, I’ve questioned its accuracy. Specifically, I have noticed frequent green encoded pixelation (or what’s considered MSU crystals) within tendons. This has been very common in the hands/wrists (particularly in the 1st extensor compartment), but also elsewhere including the foot/ankle. I know gout can involve the tendons, but I highly question what we are seeing in the tendons are really MSU crystals. In fact, I scanned my own hand (and one of my tech’s hands) and we both had green pixels in our tendons. We have been using the default thresholds for gout provided by GE. I believe these thresholds are too sensitive, with too much overlap between MSU crystal density and normal soft tissue (specifically soft tissue of higher density – like tendons or even capsular tissue). I have spoken with GE about this issue with slow progress. It’s still unclear to me how this technology accounts for the overlap in density between gout and soft tissue.
Just to clarify, this is rapid KV-switching single source DECT technology. It’s not a dual energy/dual source scanner, which there is much more literature on. At the institution I trained, we used Siemens dual energy/dual source technology and I don’t remember having this issue or seeing so frequent green-pixelation in tendons – occasional involvement of achilles or knee extensor mechanism.
I’m interested if others are using a GE revolution apex or revolution scanners for Gout imaging and if they have had similar experiences. Has anyone adjusted the default thresholds for gout? I’ve noticed small adjustments in the lower threshold on the Uricacid (HAP) pair essentially makes the green pixels in the tendons disappear. I hope these terms make sense for people using this specific technology. I’m trying to determine what thresholds are the best and what I can believe are actually MSU crystals.
Any recommendations or experiences are greatly appreciated.
Best,
Drew
