Enhancing vascular wall assessment in computed tomography: image quality optimization via small-field-of-view...

Spectral computed tomography (CT) vessel wall imaging can clearly visualize vessel wall structures, but its ability to depict fine features is limited. Small field-of-view (FOV) reconstruction technology helps improve image spatial resolution. This study sought to assess the technical efficacy of small-FOV vascular wall spectral imaging in enhancing vascular wall imaging quality compared to conventional normal-FOV imaging.

The data of 52 patients who underwent chest dual-energy CT (DECT) were retrospectively reviewed. Vascular wall spectral images were reconstructed using both small-FOV and normal-FOV protocols. Quantitatively, the contrast-to-noise ratios (CNRs) of the descending aorta between the vessel wall and periaortic fat/lumen of the small-FOV and normal-FOV groups were calculated and compared. Qualitatively, two radiologists independently evaluated the vessel wall clarity and edge smoothness of both groups. Wall thickness (WT) and descending aortic wall area (DAWA) were measured, and inter-observer intraclass correlation coefficients (ICCs) were calculated. These metrics were compared between the small-FOV and normal-FOV reconstruction groups, as well as between the patient groups with and without atherosclerotic risk factors.

The small-FOV group had significantly high CNR values than the normal-FOV group (wall-lumen: 9.45±3.28 vs. 4.86±2.16; wall-perivascular fat: 5.63±2.89 vs. 3.88±2.09, both P<0.001). The qualitative analysis also indicated that the small-FOV images were superior to the normal-FOV images (P<0.05). There were no significant differences between the small-FOV and normal-FOV groups in terms of the WT and DAWA. The mean WT values of the small-FOV and normal-FOV groups were 2.11±0.28 and 2.14±0.30 mm (Observer 1), and 2.15±0.30 and 2.13±0.28 mm (Observer 2), respectively. The mean DAWA values of the small-FOV and normal-FOV groups were 148.57±37.45 and 148.04±35.57 mm² (Observer 1), and 149.53±36.49 and 147.98±33.44 mm² (Observer 2), respectively. The patients with atherosclerotic risk factors showed significantly greater WT on the small-FOV images, and larger DAWA on both the small-FOV and normal-FOV images (all P<0.05). The ICC values for WT were 0.93 and 0.97 for the normal-FOV and small-FOV groups, respectively, and those for DAWA were 0.97 and 0.98, respectively.

The small-FOV technique significantly improved the image quality of the vascular wall spectral images, demonstrating clinical potential for detailed vascular assessment.