Dachs Theresa-Marie, Hauck Sven R, Kern Maximilian, Klausenitz Catharina, Hoffner Maximilian, Schernthaner Melanie, Abdel-Rahman Hanaa, Hannover Albert, Strassl Andreas, Steiner Irene, Loewe Christian, Funovics Martin A
Department of Bio-Medical Imaging and Image-Guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
Center for Medical Data Science, Institute of Medical Statistics, Medical University of Vienna, Vienna, Austria.
Cardiovasc Intervent Radiol. 2025 Jan;48(1):65-74. doi: 10.1007/s00270-024-03874-y. Epub 2024 Nov 5.
The visualization of peripheral in-stent restenosis using energy-integrating detector CT is challenging due to deficient spatial resolution and artifact formation. This study compares the first clinically available photon-counting detector CT to third-generation dual-source energy-integrating detector CT.
Nylon cylinders with central bores (4 mm, 2 mm), mimicking 75% and 95% stenoses, were placed inside seven different 8-mm diameter stents and filled with diluted contrast medium. Phantoms were scanned with photon-counting detector CT at slice thicknesses of 0.2 mm (available only in this scanner type), 0.5 mm, and 1.0 mm versus 0.5 mm and 1.0 mm in energy-integrating detector CT at matched CT dose indices. Contrast-to-noise ratios were calculated from attenuation rates. Residual lumen size was measured as full width at half-maximum. Subjective image quality was assessed by two independent blinded raters.
Mean contrast-to-noise ratio was lowest in photon-counting detector CT at 0.2 mm slice thickness (0%, 75%, and 95% in-stent restenosis: 6.11 ± 0.6, 5.27 ± 0.54, and 5.02 ± 0.66) and highest at 1.0 mm slice thicknesses with similar measurements in photon-counting detector CT and energy-integrating detector CT (11.46 ± 1.08, 9.94 ± 1.01, 8.26 ± 1.0 vs. 3.34 ± 1.0, 9.92 ± 0.38, 7.94 ± 1.07). Mean full width at half-maximum measurements in photon-counting detector CT at 0.2 mm slice thickness for 0%, 75%, and 95% in-stent restenosis were 8.00 ± 0.37, 3.98 ± 0.34, and 1.92 ± 0.16 mm. Full width at half-maximum was least precise in 95% in-stent restenosis at 1.0 mm slice thickness with similar measurements between scanners (1.57 ± 0.33 vs. 1.71 ± 0.15 mm). Interrater correlation coefficient was 0.75 [95% CI: [0.53; 0.86]; subjective scores were best at 0.2 mm slice thickness in photon-counting detector CT (19.43 ± 0.51 and 19.00 ± 0.68).
In phantom in-stent restenosis in 8 mm stents, we observed similar full width at half-maximum for photon-counting detector CT and energy-integrating detector CT in 0% and 75% in-stent restenosis, but at 95% in-stent restenosis, FWHM tended to be more accurate in smaller slice thicknesses in both scanners. Subjective image assessment yielded best results at 0.2 mm slice thickness in photon-counting detector CT despite lower contrast-to-noise ratio.
由于空间分辨率不足和伪影形成，使用能量积分探测器CT对周围支架内再狭窄进行可视化具有挑战性。本研究将首款临床可用的光子计数探测器CT与第三代双源能量积分探测器CT进行比较。
将带有中心孔（4毫米、2毫米）的尼龙圆柱体模拟75%和95%的狭窄，放置在七个不同直径8毫米的支架内，并填充稀释的造影剂。使用光子计数探测器CT以0.2毫米（仅这种扫描仪类型可用）、0.5毫米和1.0毫米的层厚扫描体模，而能量积分探测器CT在匹配的CT剂量指数下以0.5毫米和1.0毫米的层厚扫描。根据衰减率计算对比噪声比。残余管腔大小以半高宽测量。由两名独立的盲法评估者评估主观图像质量。
光子计数探测器CT在0.2毫米层厚时平均对比噪声比最低（0%、75%和95%支架内再狭窄：6.11±0.6、,5.27±0.54和5.02±0.66），在1.0毫米层厚时最高，光子计数探测器CT和能量积分探测器CT的测量结果相似（11.46±1.08、9.94±1.01、8.26±1.0对比3.34±1.0、9.92±0.38、7.94±1.07）。光子计数探测器CT在0.2毫米层厚时，0%、75%和95%支架内再狭窄的平均半高宽测量值分别为8.00±0.37、3.98±0.34和1.92±0.16毫米。在1.0毫米层厚的95%支架内再狭窄中，半高宽最不精确，两台扫描仪的测量结果相似（1.57±0.33对比1.71±0.15毫米）。评估者间相关系数为0.75 [95% CI：[0.53；0.86]；主观评分在光子计数探测器CT的0.2毫米层厚时最佳（19.43±0.51和19.00±0.68）。
在8毫米支架的体模支架内再狭窄中，我们观察到光子计数探测器CT和能量积分探测器CT在0%和,75%支架内再狭窄时的半高宽相似，但在95%支架内再狭窄时，两台扫描仪在较小层厚下半高宽往往更准确。尽管对比噪声比更低，但光子计数探测器CT在0.2毫米层厚时主观图像评估产生的结果最佳。
