Presentation
Preoperative radiograph for ICD placement
Patient Data
1. IVC filter limb appendage one dislodged and now present overlying the right ventricle 5 mm from the tip of the right ventricle lead. If the exact position of this tip with respect to the RV lead is of any
concern a non-contrast gated CT scan of the heart will be helpful.
2. Interventional radiology consult may be placed for removal of old IVC filter.
Annotated image showing broken appendage.
Actual filter with 12 appendages
Case Discussion
We would like to present cases where fractured appendages from Bard IVC filters were found on plain film images but missed on initial reads of CT abdomen and chest images. In the incidences of filter fractures, CT imaging carries several pitfalls due to beam hardening and the small size and thinness of the appendages. When an appendage breaks off, it does not leave an artifact or create a change in attenuation on CT imaging due to its isodensity with contrast.
If a filter’s appendage breaks off while in a patient’s body, it is important to recognize any complications for emboli through the proper use of imaging. Accounting for all 12 appendages of the filter is critical in assessing complication risk. A fractured filter likely will cause a broken off appendage to migrate to the chest. However, a common fallacy among radiologists is that CT imaging alone is sufficient to determine whether or not the filter has been fractured. In such incidences, it is crucial to correlate CT findings with plain film images, which are better than CT at visualizing the abdomen.
When looking at the CT abdomen images of a patient with a filter, the radiologist must be able to count all 12 appendages. If there are appendages unaccounted for, it is strongly recommended that plain film imaging be obtained since it is likely that a fracture has occurred. Additionally, the longer a retrievable filter is kept in a patient’s body, the more difficult it will be to remove the filter, especially without fracture. Overall, we raise the questions of whether or not the protocol of imaging patients with IVC filters should include commenting on the number and status of the appendages and whether or not plain films should automatically accompany CT abdomen images of these patients.