When I first started performing 4D-CT at Duke in 2009, the literature on 4D-CT was mostly from the surgeons and in surgical journals. Other than descriptions on the enhancement pattern, there were no articles advising radiologists on other imaging findings of a parathyroid adenoma. After reading several 4D-CT studies, I noticed that many patients had an enlarged feeding artery or a draining vein to the parathyroid adenoma seen on the arterial phase of imaging. I named this the “polar vessel sign.”

This vessel is theorized to be a normal vessel that is parasitized by the parathyroid adenoma. It is a morphologic feature that has been previously described on ultrasound but is not seen on nuclear scintigraphy or MRI because of lower spatial resolution. Our retrospective study found the polar vessel sign to be present in nearly two-thirds of parathyroid adenomas on 4D-CT, and it was more likely to be present in adenomas that have greater arterial phase enhancement.

In practice, this sign can be used along with enhancement characteristics and lesion size to increase the radiologist’s confidence that a lesion is a parathyroid adenoma. It has been incorporated as a key finding in our Duke parathyroid 4D-CT confidence score, and we recently presented a scientific abstract on the confidence score at the ASNR 2016 Annual Meeting in Washington DC.

 

Read this article at AJNR.org …