Endoleak detection using single-acquisition split-bolus dual-energy computer tomography (DECT)

Abstract

Objectives: To assess a single-phase, dual-energy computed tomography (DECT) with a split-bolus technique and reconstruction of virtual non-enhanced images for the detection of endoleaks after endovascular aneurysm repair (EVAR).

Methods: Fifty patients referred for routine follow-up post-EVAR CT and a history of at least one post-EVAR follow-up CT examination using our standard biphasic (arterial and venous phase) routine protocol (which was used as the reference standard) were included in this prospective trial. An in-patient comparison and an analysis of the split-bolus protocol and the previously used double-phase protocol were performed with regard to differences in diagnostic accuracy, radiation dose, and image quality.

Results: The analysis showed a significant reduction of radiation dose of up to 42 %, using the single-acquisition split-bolus protocol, while maintaining a comparable diagnostic accuracy (primary endoleak detection rate of 96 %). Image quality between the two protocols was comparable and only slightly inferior for the split-bolus scan (2.5 vs. 2.4).

Conclusions: Using the single-acquisition, split-bolus approach allows for a significant dose reduction while maintaining high image quality, resulting in effective endoleak identification.

Key points: • A single-acquisition, split-bolus approach allows for a significant dose reduction. • Endoleak development is the most common complication after endovascular aortic repair (EVAR). • CT angiography is the imaging modality of choice for aortic aneurysm evaluation.

Keywords: Aneurysm; Angiography; Aorta; Computed tomography; Endoleak.

Fig. 1

The first three images show the 80-kVp, 140-kVp, and mixed or fused images. Iodine colour-coded (fourth image) and virtual non-contrast (fifth image) CT data sets are also shown

Fig. 2

Flowchart of study plan

Fig. 3

The diagram illustrates the relationship between the dose-length product (mGycm) of the baseline scan and the subsequent split-bolus protocol

Fig. 4

An example of the usefulness of the split-bolus protocol. On the upper left, an endoleak can be clearly depicted on the late venous phase, whereas on the arterial phase (upper right), the endoleak is hardly visible. The iodine colour-coded data set (lower left, corresponding slice) seems to be particularly favourable for depicting endoleaks. On the lower right (split-bolus, different patient), the endoleak and the feeding artery (inferior mesenteric artery, IMA), are well demarcated

Fig. 5

An example of the usefulness of the VNC data set. On the left, the contrast-enhanced, split-bolus image shows a questionable type II endoleak, possibly arising from a right lumbar artery. On the right, the corresponding slice of the VNC data set reveals a coarse, low-density calcification at that location