Kazimierczak Wojciech, Nowak Ewa, Kazimierczak Natalia, Jankowski Tomasz, Jankowska Agnieszka, Serafin Zbigniew
Collegium Medicum, Nicolaus Copernicus University in Torun, Jagiellońska 13-15, 85-067, Bydgoszcz, Poland.
University Hospital No 1 in Bydgoszcz, Marii Skłodowskiej - Curie 9, 85-094, Bydgoszcz, Poland.
Heliyon. 2023 Oct 12;9(10):e20700. doi: 10.1016/j.heliyon.2023.e20700. eCollection 2023 Oct.
Evaluation of the diagnostic value of linearly blended (LB) and virtual monoenergetic images (VMI) reconstruction techniques with and without metal artifacts reduction (MAR) and of adaptive statistical iterative reconstructions (ASIR) in the assessment of target vessels after branched/fenestrated endovascular aortic repair (f/brEVAR) procedures.
CT scans of 28 patients were used in this study. Arterial phase of examination was obtained using a dual-energy fast-kVp switching scanner. CT numbers in the aorta, celiac trunk, superior mesenteric artery, and renal arteries were measured in the following reconstructions: LB, VMI 60 keV, VMI MAR 60 keV, VMI ASIR 60 % 60 keV. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were calculated for each reconstruction. Luminal diameters (measurements at 2 levels of stent) and subjective image quality (5-point Likert scale) were assessed (2 readers, blinded to the type of reconstruction).
The highest mean values of CNR and SNR in vascular structures were obtained in VMI MAR 60 keV (CNR 12.526 ± 2.46, SNR 17.398 ± 2.52), lower in VMI 60 keV (CNR 11.508 ± 2.01, SNR 16.524 ± 2.07) and VMI ASIR (CNR 11.086 ± 1.78, SNR 15.928 ± 1.82), and the lowest in LB (CNR 6.808 ± 0.79, SNR 11.492 ± 0.79) reconstructions. There were no statistically significant differences in the measurements of the stent width between reconstructions (p > 0.05). The highest subjective image quality was obtained in the ASIR VMI (4.25 ± 0.44) and the lowest in the MAR VMI (1.57 ± 0.5) reconstruction.
Despite obtaining the highest values of SNR and CNR in the MAR VMI reconstruction, the subjective diagnostic value was the lowest for this technique due to significant artifacts. The type of reconstruction did not significantly affect vessel diameter measurements (p > 0.05). Iterative reconstructions raised both objective and subjective image quality.
评估线性融合（LB）和虚拟单能图像（VMI）重建技术在有无金属伪影减少（MAR）情况下以及自适应统计迭代重建（ASIR）在分支/开窗血管内主动脉修复（f/brEVAR）术后评估目标血管中的诊断价值。
本研究使用了28例患者的CT扫描数据。采用双能快速kVp切换扫描仪获取检查的动脉期图像。在以下重建方式中测量主动脉、腹腔干、肠系膜上动脉和肾动脉的CT值：LB、60keV的VMI、60keV的VMI MAR、60% 60keV的VMI ASIR。计算每种重建方式的对比噪声比（CNR）和信噪比（SNR）。评估管腔直径（在支架的两个层面进行测量）和主观图像质量（采用5分制李克特量表）（两名阅片者，对重建类型不知情）。
在60keV的VMI MAR重建中，血管结构的CNR和SNR均值最高（CNR 12.526±2.46，SNR 17.398±2.52），在60keV的VMI和VMI ASIR中较低（CNR 11.508±2.01 , SNR 16.524±2.07），在LB重建中最低（CNR 6.808±0.79，SNR 11.492±0.79）。各重建方式之间支架宽度测量值无统计学显著差异（p>0.05）。在ASIR VMI重建中主观图像质量最高（4.25±0.44），在MAR VMI重建中最低（1.57±0.5）。
尽管在MAR VMI重建中获得了最高的SNR和CNR值，但由于明显的伪影，该技术的主观诊断价值最低。重建类型对血管直径测量无显著影响（p>0.05）。迭代重建提高了客观和主观图像质量。
