Non-invasive imaging of bioresorbable coronary scaffolds using CT and MRI: First in vitro experience

Accurate assessment of coronary stents after PCI using non-invasive imaging remains challenging despite technological improvements. New bioresorbable vascular scaffolds (BVS) have recently become available promising improved non-invasive imaging properties, which however have not be examined specifically yet. Therefore we investigated CT and MRI visualization properties of the only two CE-marked coronary BVSs.

The Abbott Absorb and the Elixir DESolve BVS were placed in plastic tubes filled with contrast agent and scanned with a latest generation CT respectively MR system. For CT image quality was assessed by two blinded, independent readers and in-scaffold diameter difference as well as in-scaffold attenuation difference were measured. For MRI in-scaffold signal intensity, in-scaffold lumen visibility and in-scaffold signal homogeneity were measured.

In CTA both BVSs showed no significant difference to nominal tube diameter (DESolve 101%, Absorb 100%) and to nominal tube attenuation (DESolve 96%, Absorb 98%) and were both rated with the highest score for unrestricted lumen visualization. In MRA both BVSs showed unimpaired signal intensity (DESolve 103%, Absorb 100%), lumen visibility (DESolve 92%, Absorb 89%) and lumen homogeneity (DESolve SD 7.1%, Absorb SD 9.5%) when compared to the unstented tube. There was no significant difference between CTA and MRA results of both BVSs.

Coronary BVSs show no relevant impairment for subjective and objective measures of in-stent lumen visualization by CT and MRI and will therefore allow reliable non-invasive assessment of coronary artery patency after PCI with deployment of a BVS, which is an (additional) advantage when compared to conventional stents.