The gradient field, one of the core magnetic fields in magnetic resonance imaging (MRI) systems, is generated by gradient coils and plays a critical role in spatial encoding and the generation of echo signals. The uniformity or linearity of the gradient field directly impacts the quality and distortion level of MRI images. However, traditional point measurement methods lack accuracy in assessing the linearity of gradient fields, making it difficult to provide effective parameters for image distortion correction. This paper introduced a spherical measurement-based method that involved measuring the magnetic field distribution on a sphere, followed by detailed magnetic field calculations and linearity analysis. This study, applied to assess the nonlinearity of asymmetric head gradient coils, demonstrated more comprehensive and precise results compared to point measurement methods. This advancement not only strengthens the scientific basis for the design of gradient coils but also provides more reliable parameters and methods for the accurate correction of MRI image distortions.
Magnetic Resonance Imaging/instrumentation* ; Humans ; Image Processing, Computer-Assisted/methods* ; Nonlinear Dynamics ; Magnetic Fields ; Algorithms ; Phantoms, Imaging

In recent years, the novel tracer mitoxantrone hydrochloride has been increasingly applied in thyroid cancer surgery. As a safe tracer, mitoxantrone hydrochloride enables the detection of more lymph nodes and better protection of the parathyroid glands during thyroid cancer surgery. It assists surgeons in achieving more precise treatment, thereby improving the prognosis of patients. However, research on the use of mitoxantrone in thyroid cancer surgery remains limited, and standardized operating protocols are lacking. This article explores the current applications and future development of mitoxantrone in thyroid cancer surgery, aiming to provide a reference for clinical practice.

Objective:To analyze effect of miR-532-3p on macrophage polarization in rats with chronic kidney disease(CKD)through targeted inhibition of Notch1 signal pathway.Methods:A total of 75 SD rats were divided into control group,CKD group,ago-NC group,ago-miR-532-3p group and FLI-06 group,except for control group,CKD models were constructed and corresponding plas-mids and inhibitors were injected,control group and CKD group were replaced with same amount of normal saline.Serum creatinine(Scr),blood urea nitrogen(BUN),TNF-α,IL-1β and IL-10 were measured by ELISA,HE staining and Masson staining were used to observe renal tissue pathology and renal fibrosis in rats,flow cytometry was used to detect CD11c+and CD206+of macrophages,miR-532-3p expression in rat kidney tissue was detected by qRT-PCR,Notch1 protein was detected by Western blot;target binding of miR-532-3p to Notch1 was determined by double luciferase reporter gene.Results:Structure of glomerulus,renal tubules and epithelial cells was complete,cell boundaries were clear,and cells were arranged neatly in control group;glomerular epithelial cell necrosis,mesangial matrix,glomerulosclerosis,inflammatory cell infiltration and renal fibrosis were increased in CKD group;compared with CKD group,damage degree of glomerulus and tubules,inflammatory infiltration cells and renal fibrosis degree in ago-miR-532-3p group and FLI-06 group were reduced;compared with control group,serum Scr,BUN,TNF-α,IL-1β,proportion of CD11c+,CD11c+/CD206+and Notch1 protein expression in macrophages of renal tissue were increased,serum IL-10 level,CD206+and miR-532-3p in renal tissue were decreased(P<0.05);compared with CKD group,serum Scr,BUN,TNF-α,IL-1β,proportion of CD11c+,CD11c+/CD206+and Notch1 protein expression in macrophages of renal tissue in ago-miR-532-3p group and FLI-06 group were decreased,serum IL-10 level,CD206+and miR-532-3p in renal tissue were increased(P<0.05);miR-532-3p targeted Notch1,and overexpression of miR-532-3p inhibited Notch1 protein expression.Conclusion:Promoting expression of miR-532-3p protects kidney tissue of CKD rats by inhibiting Notch1 pathway,which may be due to regulating polarization of macrophages.

Objective:To analyze effect of miR-532-3p on macrophage polarization in rats with chronic kidney disease(CKD)through targeted inhibition of Notch1 signal pathway.Methods:A total of 75 SD rats were divided into control group,CKD group,ago-NC group,ago-miR-532-3p group and FLI-06 group,except for control group,CKD models were constructed and corresponding plas-mids and inhibitors were injected,control group and CKD group were replaced with same amount of normal saline.Serum creatinine(Scr),blood urea nitrogen(BUN),TNF-α,IL-1β and IL-10 were measured by ELISA,HE staining and Masson staining were used to observe renal tissue pathology and renal fibrosis in rats,flow cytometry was used to detect CD11c+and CD206+of macrophages,miR-532-3p expression in rat kidney tissue was detected by qRT-PCR,Notch1 protein was detected by Western blot;target binding of miR-532-3p to Notch1 was determined by double luciferase reporter gene.Results:Structure of glomerulus,renal tubules and epithelial cells was complete,cell boundaries were clear,and cells were arranged neatly in control group;glomerular epithelial cell necrosis,mesangial matrix,glomerulosclerosis,inflammatory cell infiltration and renal fibrosis were increased in CKD group;compared with CKD group,damage degree of glomerulus and tubules,inflammatory infiltration cells and renal fibrosis degree in ago-miR-532-3p group and FLI-06 group were reduced;compared with control group,serum Scr,BUN,TNF-α,IL-1β,proportion of CD11c+,CD11c+/CD206+and Notch1 protein expression in macrophages of renal tissue were increased,serum IL-10 level,CD206+and miR-532-3p in renal tissue were decreased(P<0.05);compared with CKD group,serum Scr,BUN,TNF-α,IL-1β,proportion of CD11c+,CD11c+/CD206+and Notch1 protein expression in macrophages of renal tissue in ago-miR-532-3p group and FLI-06 group were decreased,serum IL-10 level,CD206+and miR-532-3p in renal tissue were increased(P<0.05);miR-532-3p targeted Notch1,and overexpression of miR-532-3p inhibited Notch1 protein expression.Conclusion:Promoting expression of miR-532-3p protects kidney tissue of CKD rats by inhibiting Notch1 pathway,which may be due to regulating polarization of macrophages.

In recent years, the novel tracer mitoxantrone hydrochloride has been increasingly applied in thyroid cancer surgery. As a safe tracer, mitoxantrone hydrochloride enables the detection of more lymph nodes and better protection of the parathyroid glands during thyroid cancer surgery. It assists surgeons in achieving more precise treatment, thereby improving the prognosis of patients. However, research on the use of mitoxantrone in thyroid cancer surgery remains limited, and standardized operating protocols are lacking. This article explores the current applications and future development of mitoxantrone in thyroid cancer surgery, aiming to provide a reference for clinical practice.

Objective:To explore the predictive value of qualitative and quantitative parameters of dual-layer spectral detector CT plain scan on the invasiveness of pure ground-glass pulmonary nodules (pGGNs).Methods:Clinical and imaging data of 113 patients (119 pGGNs) with pathology-proven lung adenocarcinoma who underwent preoperative dual-layer spectral detector CT plain scan in Tianjin Medical University Cancer Institute and Hospital from November 2019 to December 2020 were retrospectively analyzed. According to invasiveness, pGGNs were divided into non-invasive adenocarcinoma (non-IA) group ( n=66) and IA group ( n=53). The non-IA group included atypical adenomatous hyperplasia ( n=10), adenocarcinoma in situ ( n=26) and minimally invasive adenocarcinoma ( n=30). The qualitative parameters were nodule shape, lung-tumor interface, lobulation, spiculation, pleural retraction, bubblelike lucency, air bronchogram and vascular abnormality. The quantitative parameters included nodule size, effective atomic number (Z eff), CT value on 120 kVp images (CT 120 kVp) and virtual monoenergetic images from 40 keV to 200 keV (CT 40 keV-CT 200 keV), and slope of energy spectrum curve (λHU). The χ 2 test, Mann-Whitney U test and independent sample t test were used to analyze the parameter differences between non-IA group and IA group. Multivariate logistic regression analysis was performed to screen out independent predictors. Receiver operating characteristic (ROC) curve was used to assess the diagnostic efficacy of single predictor and combined independent factors for the invasiveness of pGGN. Results:Significant differences were found in nodule shape, lobulation, air bronchogram, vascular abnormality, nodules size, Z eff, CT 120 kVp and CT 40 keV-CT 200 keV between non-IA and IA groups ( P<0.05). The maltivariate logistic regression analysis showed that nodule size [odds ratio 9.269, 95% confidence interval (CI) 1.640-52.395, P=0.012] CT 200 keV (odds ratio 1.012, 95%CI 1.006-1.019, P<0.001) as well as vascular abnormality sign (odds ratio 4.940, 95%CI 1.358-17.969, P=0.015) were independent predictors of pGGN invasiveness. ROC curve analysis of a single independent predictor and a combination of the three factors showed that the area under the curve (AUC) of the combination of three factors predicting the invasiveness of pGGN was significantly higher than the AUC of vascular abnormality sign ( Z=4.01, P<0.001) and CT 200 keV ( Z=3.25, P=0.001), while there was no significant difference in AUC between the combination of the three factors and nodule size ( Z=1.94, P=0.052). The AUC of the combination of the three independent predictors was 0.909, and the sensitivity and specificity for predicting pGGN invasion were 81.1% and 86.4%, respectively, using a threshold of 0.505. Conclusion:The combination of qualitative and quantitative parameters of dual-layer spectral detector CT plain scan shows a high predictive value for the invasiveness of pGGNs.

Objective To evaluate changes in morphology of the cesarean scar and uterus between one and two years after cesarean section using high-resolution, three dimensional T2-weighted sampling perfection with application optimized contrast using different flip angle evolutions Magnetic Resonance Imaging (3D T2w SPACE MRI). Methods This prospective study was performed to investigate morphological changes in the cesarean scars and uterus from one to two years after cesarean section using high-resolution, 3D T2w SPACE MRI. The healthy volunteers having no childbearing history were recruited as the controls. All data were measured by two experienced radiologists. All data with normal distribution between the one-year and two-year groups were compared using a paired-sample t test or independent t test. Results Finally, 46 women took a pelvic MR examination one year after cesarean section, and a subset of 15 completed the same examination again after two years of cesarean section. Both the uterine length and the anterior wall thickness after two years of cesarean section (5.75 ± 0.46 and 1.45 ± 0.35 cm) were significantly greater than those measured at one year (5.33 ± 0.59 and 1.25 ± 0.27 cm) (t = -2.363 and -2.175, P= 0.033 and 0.048). No significant difference was shown in myometrial thickness two years after cesarean section (1.45 ± 0.35 cm) with respect to the control group (1.58 ± 0.21 cm, P = 0.170). Nine women who underwent MRI twice were considered to have scar diverticula one year after cesarean section, and still had diverticula two years after cesarean section. The thickness, height, and width of the uterine scar showed no significant change from one to two years (all P > 0.05). Conclusions 3D T2w SPACE MRI provides overall morphologic details and shows dynamic changes in the scar and the uterus between one and two years after cesarean section. Scar morphology after cesarean section reached relatively stable one year after cesarean section, and uterine morphology was closer to normal two years after cesarean section.

Objective:To compare the effects of different intraocular infusion solutions on histology and function of retina.Methods:Human corneal endothelial cells (HCEC), human retinal pigment epithelium (HRPE) cells and rat retinal ganglion cells (RGC) were divided into normal control group, balanced saline solution (BSS) group and compound electrolyte intraocular irrigating solution (CEIIS) group, and the cells were cultured in 10% DMEM/F12 medium, BSS and CEIIS for 12, 24 and 48 hours, respectively, according to grouping.The proliferation absorbance value of cultured cells was measured by cell counting kit-8 (CCK8) method.The expression of apoptosis related proteins in cultured cells was detected by cellular immunofluorescence staining.The cell apoptosis rate and cell cycle were measured by flow cytometry.The mitochondrial damage was detected by lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) quantitative detection kit.Fifteen New Zealand white rabbits were randomly divided into control group ( n=3), BSS group ( n=6) and CEIIS group ( n=6). The left eyes were taken for vitrectomy and different intraocular perfusion fluids were used during vitrectomy according to grouping.The retinal function of operative eyes was measured by flash electroretinogram (ERG) before operation and 24 hours after operation, and the structural changes of each layer of retina were detected by optical coherence tomography (OCT). The early apoptosis of retinal cells was detected by TUNEL staining.The expressions of cytochrome C and bax protein in retina were detected by immunohistochemical staining.The ultrastructural changes of retina were observed under a transmission electron microscope.The use and care of animals complied with the ARVO statement.This study protocol was approved by an Ethics Committee of Peking University People's Hospital (No.2019PHE059). Results:The three kinds of cultured cells in BSS and CEIIS groups were damaged in various degrees.With the extension of culture time, proliferated cells were decreased and the number of apoptotic cells was increased.Compared with the BSS group, cultured cells in the CEIIS group were dense and in orderly arrangement with uniform morphology and size.The apoptosis rates of HRPE cells and RGC in the BSS group were (37.157±6.918)% and (29.993±12.330)%, respectively, which were significantly higher than (4.163±1.310)% and (6.337±1.903)% in the CEIIS group ( P=0.003, 0.045). There was no significant difference in G0/G1+ S phase ratio of HCEC and HRPE cells among the normal control group, BSS group and CEIIS group (HCEC: F=2.226, P=0.189; HRPE: F=2.634, P=0.151), and the proportion of G2/M division arrest phase of RGC in the BSS group was significantly higher than that in the normal control group and CEIIS group ( P=0.047, 0.024). The proliferation absorbance values of HCEC, HRPE cells and RGC in the CEIIS group were significantly higher than those in the BSS group at each culture time point (all at P<0.05). The fluorescence intensity of cytochrome C, bax, caspase-3 and caspase-9 proteins in the BSS group was stronger than that in the normal control group and CEIIS group, and the fluorescence intensity of bcl-2 was weaker than that in the CEIIS group, and the fluorescence intensity of zonula occluden-1 (ZO-1) was weaker than that in the normal control group and CEIIS group.The release level of LDH in the BSS group was significantly higher than that in the CEIIS group at different time points (all at P<0.001). After 48 hours of culture, the release level of SDH in the BSS group was significantly higher than that in the CEIIS group ( P<0.05). No retinal histological abnormalities was found through OCT examination of rabbit eyes after vitrectomy in the two groups, but transmission electron microscopy showed that there were different degrees of loose arrangement of retinal photoreceptor cells, a large number of photoreceptor outer membrane discs falling off and vacuolar degeneration in the two groups, especially in the BSS group.TUNEL staining showed that the apoptotic cells were mainly located in the inner nuclear layer and RGC layer.The number of apoptotic retinal cells was (135.2±22.8)/high-power field of vision in the BSS group, which was significantly higher than (81.3±17.7)/high-power field of vision in the CEIIS group ( t=4.175, P=0.002). Full field flash ERG showed that the amplitudes of scotopic 3.0 ERG a- and b-wave in the CEIIS group after operation were significantly lower than those before operation, but the differences were not statistically significant (all at P>0.05). The amplitudes of scotopic 3.0 ERG a- and b-wave in the BSS group after operation were significantly lower than those before operation ( P=0.026, 0.010). Conclusions:In vivo and in vitro research results show that compared with BSS, there were few apoptotic cells in retinal tissue after vitrectomy perfused by CEIIS.

Objective:To investigate the correlation between amide proton transfer-weighted (APTw) values and Ki-67 labeling index of cervical squamous cell carcinoma.Methods:From October 2017 to December 2018, 24 patients with cervical squamous cell carcinoma [International Federation of Gynecology and Obstetrics (FIGO) stage Ⅰ-Ⅲ] were prospectively enrolled in Peking Union Medical College Hospital and underwent pelvic morphological MRI on a 3.0 T MR scanner, including three-dimensional turbo-spin-echo APTw imaging and DWI. The maximum diameters of the lesions, APTw values and ADC values on the slice with the maximum diameter of the lesion were independently measured by two radiologists. The ICC was computed to evaluate the inter-observer consistency. Ki-67 immunohistochemical expression status was assessed by one pathologist. The Pearson correlation analysis was performed between the APTw values, maximum diameters, ADC values and Ki-67 labeling index.Results:The APTw values of cervical squamous cell carcinoma were (2.9±0.5)%. Inter-observer ICC was 0.972 (95%CI 0.937-0.988). The APTw values were positively moderately correlated with Ki-67 labeling index [(61.9±18.7)%, r=0.532, P=0.008]. The maximum diameters of the lesions were (28.7±10.6) mm. The mean ADC values were (0.998±0.217)×10 -3 mm 2/s. No correlations were found between maximum diameters, ADC values and Ki-67 labeling index ( r=0.038, P=0.859; r=0.238, P=0.263). Conclusion:APTw values can partially reveal the proliferation status of cervical squamous cell carcinoma.

Objective:To compare the efficacy and safety between the generic pemetrexed produced by Sichuan Huiyu Pharmaceutical Co., LTD and the original pemetrexed produced by Eli Lilly Nederland B.V. in the treatment for patients with non-small cell lung cancer (NSCLC).Methods:The subjects were patients who received generic and original pemetrexed from March 2019 to December 2019 in Cancer Hospital of Chinese Academy of Medical Sciences. Demographic characteristics (age, gender, past history, etc.), treatment-related information (NSCLC stage, treatment regimen, underlying diseases, etc.), occurrence of adverse events, and efficacy evaluation in patients were collected. Patients were divided into the generic group and the original group, and the general situation, clinical use of pemetrexed, and adverse events in patients in the 2 groups were compared. After propensity score matching for 7 variables such as gender, age, body weight, body surface area, Eastern Cooperative Oncology Group (ECOG) score, tumor stage, and standardized chemotherapy dose, the efficacy and safety in patients between the 2 groups after 2 cycles of treatment with generic and original pemetrexed were compared.Results:A total of 182 patients were enrolled in the study, including 85 patients in the generic group and 97 patients in the original group. The differences in age, gender, ECOG score, body weight and body surface area, and underlying chronic diseases between the 2 groups were not statistically significant (all P>0.05). The patients with advanced stage Ⅲ and Ⅳ cancer in the generic group were significantly more than those in the original group [92%(78/85) vs. 79% (77/97), P=0.032]. The proportion of palliative chemotherapy and maintenance chemotherapy in the generic group was higher than that in the original group ( P<0.001). The difference in median dosage between the generic group and the original group was statistically significant [900 (800, 1 000) mg/m 2vs. 800 (800, 900) mg/m 2, P=0.019]. The difference in chemotherapy cycles between the 2 groups was statistically significant [5 (4, 10) vs. 4 (2, 4), P<0.001]. The overall incidence of adverse events and the incidences of bone marrow toxicity and liver toxicity in the generic group were higher than those in the original group ( P=0.018, P=0.037, P=0.018). After propensity score matching, there were 38 patients in both groups, and the differences in the objective response rate, disease control rate and the incidence of adverse events between the 2 groups were not statistically significant [26% (10/38) vs. 32%(12/38), P=0.723; 89% (34/38) vs. 96% (36/38), P=0.674; 47% (18/38) vs. 24%(9/38), P=0.055]. Conclusion:After propensity score matching, the difference in the efficacy and safety between the generic and the original pemetrexed was not significant.