Case 1199_06 -- Gas Formation in the Uterus after Embolization for Fibroids

Gas Formation in the Uterus after
Embolization for Fibroids

R.L. Worthington-Kirsch, M.D.
Delaware Valley Imaging, Ltd.

Fig. 1. Axial image from MRI pre-UAE shows large fibroid in the uterine body.

Fig. 2. KUB obtained on post-UAE day 14 shows extensive gas throughout the fibroid uterus.

Case Reference No. CC-1199-06

Our first uterine artery embolization (UAE) patient presented to the emergency room 14 days after her embolization procedure with continued severe abdominal pain, fever, and elevated WBC. Her pre-UAE MRI (Figure 1) showed a very large dominant fibroid. Plain film (Figure 2) and CT examination (Figure3) showed extensive gas accumulation in the fibroid. Assuming that this indicated abscess formation, hysterectomy was performed. All cultures were negative and the patient's fever and leukocytosis returned to normal shortly after surgery.

We have since seen this appearance in a number of patients imaged from as soon as a day after UAE to as many as 3-4 weeks after UAE. (Figure 4).

This is likely nitrogen gas filling potential spaces left by tissue infarction/dessication - similar to the gas seen after ethanol ablation of the kidney or the vacuum disk effect. In retrospect it is likely that the first patient had severe post-embolization syndrome, not an infection. It is important to be aware of this finding so that unnecessary surgery is avoided.

Fig. 3. this caption is not complete Axial CT image obtained on post-UAE day 14 at a similar level to

Fig. 4. CT performed a few weeks after UAE shows gas within the uterus similar to the first case described above.

Questions:

1) Under what circumstances should you image the uterus in the immediate post-UAE period?

2) Given that post-embolization syndrome (PES) includes persistent pain with fever and leukocytosis, how do you separate the patient with post-embolization syndrome from a patient developing an infection?