Factors Affecting Image Resolution in a Modern Angiographic Suite: A Phantom-Based Study

Improvements in angiographic imaging systems technology provide options to decrease radiation exposure. The effect of these variations on image resolution is unknown.

Using an American National Standards Institution phantom, a high-contrast (line-pair) and low contrast (Gammex 151) phantoms, 5 second images were acquired using a Phillips Allure angiographic suite, using fluoroscopic capture (FC) as well as cineangiography (CA) in posterior anterior (PA) and left anterior oblique (LAO) projections as well as high and low table positions. Image resolutions were measured as ranked by three independent trained observers blinded to the purpose of the assessments. Comparative analyses were performed. Interobserver agreement was evaluated.

High contrast image resolution was significantly lower with FC compared to CA (median [interquartile range], 1.69 [1.52-1.69] mm, vs 2.09 [1.88-2.09] mm, P < 0.001). No significant differences were observed in between PA and LAO projections as well as low and high table positions. Low contrast resolution was also lower with FC compared to CA (5 [6.5-5] vs 3 [5-3] mm, P < 0.001). No significant differences in high-contrast or low-contrast resolution were noted between PA and LAO projections, or high and low table positions. Both low and high-contrast image resolution improved with higher radiation exposure. Good interobserver agreement was noted (Fleiss-Kappa ranging from 0.69-0.74).

Image resolution was perceived to be better with CA compared to FC, although not significantly affected by beam angulation or table height. Aligning resolution needs with imaging modality and maximizing table height may improve procedural efficacy and safety.