Experimental feasibility of dual contrast agent based spectral photon-counting computed tomografy for detection of endoleaks following EVAR

Zielsetzung:

After endovascular aortic repair (EVAR) discrimination of leaking contrast media and calcifications of similar attenuation within the aneurysm sac is challenging and often requires multiple CT acquisitions. Dual contrast agent based spectral photon-counting CT may provide reliable detection of endoleaks with a single CT acquisition.

Material und Methodik:

To experimentally evaluate the potential of spectral photon-counting computed tomografy (SPCCT), an aortic phantom was in-house designed and produced. A centrally located stent lined compartment was filled with water as well as iodine and gadolinium mimicking enhanced blood within the aortic lumen. Representing the endoleak, adjacent compartments contained either one of the contrast agents or calcium chlorine to mimic calcifications. After data acquisition with a modified clinical base, small field-of-view SPCCT prototype scanner with multi-energy bins, material decomposition was performed to generate iodine, gadolinium and calcium maps.

Ergebnisse:

In a conventional CT slice, Hounsfield Units of the different compartments were similar ranging from about 145 HU up 170 HU. Material specific maps clearly differentiate the distributions, within the compartments filled with iodine, gadolinium or calcium.

Schlussfolgerungen:

A single dual contrast agent based spectral photon-counting CT scan may replace conventional CT scans in native, arterial and delayed phase to detect endoleaks of different flow rates without interference from existing calcifications after endovascular aortic repair. It is a unique feature of our method to capture different contrast media dynamics in a single scan. Additionally, a significant reduction of radiation exposure is enabled.