Objective To develop a superparamagnetic iron oxide nanoparticles ( SPIO ) based on MRI probe specifically targeting human epidermal growth factor receptor 2 (HER2) and explore its value as MRI positive contrast agents in vitro.Methods (1) The superparamagnetic iron oxide ( PS) was obtained by means of classical coprecipitation in polylactic acid solution , then coupled with fluorescein isothiocyanate (FITC) labeled LTVSPYW to develop the targeted probe ( FITC-LTVSPWY-PS).The particle size was measured under transmission electron microscope.Relaxation rate was detected by 3.0 T MR scanner.(2) Climbing films of human breast cancer cell MCF-7 were prepared and incubated with FITC-LTVSPWY-SPIO, then fluorescence distribution was observed under inverted microscope.And distribution of iron particles was confirmed by prussian blue staining.(3) MCF-7 and MDA-MB-231 cells were incubated with FITC-LTVSPWY-SPIO and PS, respectively.MCF-7 incubated with FITC-LTVSPWY-PS were used as experimental group, MCF-7 treated with PS as control group , and cells added with nothing as blank group.There were 3 samples in each group.The MR imaging was performed only once and T 2 WI signal intensity of cells was recorded.The comparison of T 2 signal intensity among groups was conducted by using one-way ANOVA.Results The core and surface size of nanoparticles were (13.9 ±1.6) nm and (122.0 ±5.5) nm respectively.Zeta potential and relaxation rate of the FITC-LTVSPWY-PS were ( -30.7 ±2.2 ) mV and 70.7 m· M-1 · s-1 respectively, and the PS were (28.1 ±2.8) mV and 72.1 m· M-1 · s-1 respectively.The fluorescence could be seen on the surface of MCF-7 cells, and the prussian blue staining showed that FITC-LTVSPWY-PS could specifically target HER 2-positive cells.The low signal on T 2 WI was observed in MCF-7 cells incubated with FITC-LTVSPWY-PS, whereas cells treated with PS and blank group showed equal signals , the T2 values were ( 61.8 ±5.7 ) , ( 101.6 ±2.5 ) and ( 103.5 ±1.9 ) ms respectively.Significant difference existed among these groups ( F =355.698, P <0.05 ).Conclusions The MR targeting probe FITC-LTVSPWY-PS was prepared successfully , its physical characterization and magnetic properties could target the HER 2 highly expressing on the surface of breast cancer cells and meet the need of targeted imaging.It provides an important tool for MR molecular imaging.

【Objective】 To evaluate the application value of the three-point localization method in improving the quality and efficiency of four-chamber view acquisition in cardiac magnetic resonance (CMR) imaging. 【Methods】 A total of 215 patients who underwent four-chamber view in CMR imaging from January 2022 to October 2023 were retrospectively enrolled and divided into two groups. The control group (n=109) received traditional localization method while the study group (n=106) received three-point localization method. The image quality of mitral valve, tricuspid valve and cruciform structure in four-chamber view images were assessed by two radiologists using a Likert 4-piont scale. The time-consumption from scout imaging to the finish of four-chamber view imaging was recorded. Constituent data and numeral data were compared by Chi-square test and two-sample t test, respectively. Kappa test was used to analyze the inter-observer consistency. 【Results】 There were no significant inter-group differences in gender, age, disease profile, or the radiographers’ experience. The mean quality scores of the mitral valve, tricuspid valve and cruciform structure in the control group and the study group were 3.44±0.64 and 3.63±0.49 (P=0.023), 3.43±0.67 and 3.53±0.60(P=0.202), 3.71±0.49 and 3.83±0.35 (P=0.047), respectively. The image quality score was higher in the study group than in the control group, with the differences in mitral valve and cruciform structure reaching statistical significance. The time-consumption for obtaining four-chamber view for the control group and the study group was 11.67±3.49 minutes and 7.212±1.83 minutes, respectively, with statistically significant differences (P<0.001). 【Conclusion】 Compared with the traditional localization method, the three-point localization method provides better image quality in four-chamber view imaging with shortened imaging time.

【Objective】 To investigate the value of abdominal aortic combined with routine one-stop triple rule-out computed tomography angiography (TRO-CTA) in the examination of patients with acute chest pain. 【Methods】 A total of 1 482 patients with nontraumatic chest pain were included in this retrospective study. Of them 414 patients underwent the conventional TRO-CTA scanning while 1 068 patients underwent TRO-CTA that included the abdominal aorta (TRO-CTAwAA) under the request of clinicians. All scanning parameters were the same, except the scanning range for the third phase in TRO-CTA: conventional TRO-CTA covered only the thoracic aorta, while TRO-CTAwAA extended to the entire aorta. Patient etiology was investigated and the detection rates of major vessel abnormalities (aortic dissection, aneurysm, penetrating ulcer, intramural hematoma, vascular occlusion, and thrombosis) between the two groups was compared using chi square tests. The radiation dose (CTDIvol and DLP) and scanning time between the two groups were compared using analysis of variance (ANOVA). 【Results】 The TRO-CTAwAA had significantly higher detection rate of major artery abnormalities than the TRO-CTA group (35.1% vs. 4.8%, P<0.001). In the TRO-CTAwAA group, 26.5% of the vascular anomalies were detected in both the thoracic and abdominal aortas, and another 8.6% were seen only in the abdominal aorta. With regard to the radiation dose between the two groups, the total DLP was significantly higher in the TRO-CTAwAA group than in the conventional TRO-CTA group (P<0.001). The two groups did not significantly differ in scanning time (P=0.410). 【Conclusion】 TRO-CTA with scan range including the abdominal aorta significantly improves the detection rate for major vessel abnormalities in patients with chest pain without increasing the examination process.

【Objective】 To evaluate the relationship between the pericoronary fat attenuation index (FAI) and the image reconstruction parameters of computed tomography (CT) coronary angiography, including reconstruction kernel, iterative reconstruction algorithm and image thickness. 【Methods】 Forty-four CT coronary angiography scans were prospectively enrolled. All scans were reconstructed by three means as follows: ① Four different kernels (Soft_AA, Soft_BA, Soft_CA, and Soft_DA, sharpness from low to high) as the iterative reconstruction algorithm (KARL5) and image thickness (0.5 mm) remained unchanged. ② Filtered back projection (FBP) and iterative reconstruction kernel (KARL5) as the kernel and image thickness (0.5 mm) remained unchanged. ③ Different image thickness (0.5 mm and 1 mm) as the kernel (Soft_AA) and iterative reconstruction algorithm (KARL5) remained unchanged. The FAI of left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA) was calculated using a dedicated software. Paired t-test and analysis of variance were used for statistical analysis. 【Results】 For LAD, LCX and RCA: ① The differences of FAI among different reconstruction kernels reached statistical significance (P<0.001), and FAI decreased as the sharper kernel was used. ② Compared with FBP, the FAI of KARL5-reconstructed images significantly increased (P<0.001). ③ Compared with 0.5 mm, the FAI of images with 1.0 mm thickness significantly decreased (P<0.001). 【Conclusion】 The kernel, iterative reconstruction algorithms, and image thickness all have a significant impact on the FAI of each coronary artery. When using FAI for clinical diagnosis, the effect of CT reconstruction parameters should be taken into account.