Achieving single-contrast administration for enhanced chest CT and contrast-enhanced spectral mammography without compromising diagnostic quality: a comparative study

To explore the clinical value of contrast-enhanced spectral mammography (CESM) combined with enhanced computed tomography (CT) scan using a single injection of contrast material in patients with breast cancer. This study enrolled patients who underwent CESM independently as the CESM group and those who underwent CESM immediately after an enhanced CT scan as the CESM after CT group. Differences in diagnostic outcomes between the two examination methods were assessed through qualitative analysis (degree of enhancement, sign of enhancement, and image quality score) and quantitative analysis (the gray value of the lesion and background, relative degree of enhancement, and contrast-to-noise ratio values from the craniocaudal and mediolateral oblique view images). We analyzed 109 lesions from 104 patients who underwent CESM independently (CESM group) and 46 lesions from 46 patients who underwent CESM immediately after enhanced CT scan (CESM after CT group). In the qualitative analysis, the degree of enhancement, enhancement pattern, and image quality score did not significantly differ between the two groups (P = 0.443, P = 0.658, and P = 0.449, respectively) (all P > 0.05). In the quantitative analysis, mean gray value (GV) of the lesion and background from the craniocaudal and mediolateral oblique view images between the two groups was (2126.779 ± 24.442, 2126.421 ± 27.731, 2077.101 ± 14.215, 2073.516 ± 7.120, 2118.149 ± 19.357, 2119.770 ± 21.951, 2076.030 ± 6.503, 2073.820 ± 8.796), mean relative degree of enhancement (RDE) from the craniocaudal and mediolateral oblique view images between the two groups was (0.024 ± 0.013, 0.026 ± 0.012, 0.020 ± 0.009, 0.022 ± 0.011), mean contrast-to-noise ratio (CNR) values from the craniocaudal and mediolateral oblique view images between the two groups was (5.785 ± 3.370, 5.939 ± 2.600, 4.894 ± 2.342, 5.135 ± 2.426). The GV of the lesion and background, RDE, and CNR values from the craniocaudal and mediolateral oblique view images did not significantly differ between the two groups (P = 0.936, P = 0.106, P = 0.648, P = 0.085, P = 0.492, P = 0.272, P = 0.782, and P = 0.563) (all P > 0.05). CESM combined with enhanced CT scan using a single injection of contrast agent is feasible. This strategy reduces the contrast agent dose for patients requiring both examinations, further minimizing kidney damage.