Objective To evaluate the value of an optimized three-dimensional inversion-recovery with real reconstruction (3D-real IR) sequence with a longer repetition time (TR, 16 000 ms) based on modulated flip angle technique in refocused imaging with extended echo train (MATRIX) in the endolymphatic hydrops (EH) imaging after intratympanic gadolinium (Gd) administration, and to compare it with a conventional 3D-real IR based on the turbo spin echo (TSE) sequence. Methods From July 2021 to November 2022, twenty-seven patients received both the conventional and optimized 3D-real IR sequences after bilateral intratympanic Gd administration. Images of the two sequences were qualitativly evaluated and compared. Contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and area ratio of endolymph against the total lymphatic space from the two sequences were measured and compared. Results 14(25.9%) ears with insufficient contrast for the EH diagnosis on the conventional sequence were clearly displayed on the optimized sequence. Image score, CNR and SNR of the optimized sequence were significantly higher than those of the conventional sequence (P ＜ 0.001). The scanning time of two sequences was similar. The area ratio of endolymph against the total lymphatic space in the cochlear was significantly higher on the conventional 3D-real IR than that on the optimized 3D-real IR (P ＜ 0.001); there was no statistical difference in the vestibule between the two sequences. Conclusions Compared with conventional sequence, optimized 3D-real IR sequence with a longer TR may be better for evaluation of EH after intratympanic Gd administration.

Objective To investigate the value of artificial intelligence-assisted compressed sensing (ACS) technology for intravenous gadolinium contrast-enhanced magnetic resonance imaging of the inner ear using three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence. Methods The patients received gadolinium contrast-enhanced magnetic resonance imaging using ACS and united compressed sensing (uCS) 3D-FLAIR at Zhongshan Hospital, Fudan University from January to November 2024 were prospectively enrolled. The repetition time was 16 000 ms, and acquisition time was 6 min 40 s and 10 min 24 s in ACS 3D-FLAIR and uCS 3D-FLAIR, respectively. The images on the two sequences were evaluated independently by two radiologists. The image quality of the two sequences was subjectively evaluated and compared. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared between the two sequences. The grading consistencies using two sequences and between the two doctors were analyzed. Results There was no statistically difference in subjective score of image quality between the two sequences. SNR and CNR of the ACS 3D-FLAIR sequence were significantly higher than those of the uCS 3D-FLAIR sequence (P＜0.001). The kappa values of grades of cochlear and vestibular endolymphatic hydrops were 0.942 and 0.888 using two sequences (P＜0.001). The kappa values of grades of cochlear and vestibular endolymphatic hydrops using the ACS 3D-FLAIR sequence between the two doctors were 0.784 and 0.831, respectively (P＜0.001); the kappa values of grades of cochlear and vestibular endolymphatic hydrops using uCS 3D-FLAIR sequence between the two doctors were 0.725 and 0.756, respectively (P＜0.001). Conclusions ACS 3D-FLAIR could provide higher SNR and CNR than uCS 3D-FLAIR, and is more suitable for intravenous gadolinium contrast-enhanced magnetic resonance imaging of the inner ear; the endolymphatic hydrops grades using ACS 3D-FLAIR is similar to use uCS 3D-FLAIR.

Objective:To differentiate the nodular regenerative hyperplasia (NRH) from colorectal liver metastases in patients during chemotherapy based on magnetic resonance imaging (MRI) scan.Methods:Clinical data of 58 patients with liver NRH ( n=18) or metastases ( n=40) during postoperative chemotherapy for colorectal cancer admitted to Zhongshan Hospital Affiliated to Fudan University from July 2014 to December 2021 were retrospectively analyzed, including 39 males and 19 females, aged (56.8±10.6) years. The morphology, margin, plain scan and enhanced features of the lesions were compared, and the apparent diffusion coefficient (ADC) values of the lesions and the surrounding normal liver parenchyma were measured. Results:A total of 45 lesions were found in 18 patients with liver NRH, and 111 lesions in 40 patients with liver metastases. The distribution of lesions between liver NRH and liver metastases showed a statistically significant difference ( χ2=71.22, P<0.001). The boundaries of lesions in liver NRH were clearer than those in liver metastases [82.2% (37/45) vs. 46.8% (52/111), χ2=11.43, P=0.016]. The ADC values of 45 liver NRH lesions were (1.54±0.60)×10 -3 mm 2/s, which were close to the ADC values of the surrounding normal liver tissue (1.57±0.63)×10 -3 mm 2/s ( t=0.59, P=0.167). The ADC values of 111 liver metastatic lesions were (1.09±0.04)×10 -3 mm 2/s, which were lower than those of the surrounding normal liver tissue (1.50±0.10)×10 -3 mm 2/s ( t=30.31, P<0.001). The ADC values of liver metastatic lesions were lower than those of the liver NRH lesions [(1.09±0.04)×10 -3 mm 2/s vs. (1.54±0.60)×10 -3 mm 2/s, t=10.82, P<0.001]. Dynamic contrast-enhanced MRI scans showed that the arterial phase of 45 liver NRH lesions was more significantly enhanced, and continued to be enhanced in the portal vein, late and delayed phases. Conclusion:NRH lesions that occur in patients undergoing chemotherapy for colorectal cancer have clear boundaries, unrestricted diffusion, obvious enhancement in the arterial phase, and continuous enhancement in the portal venous phase and delayed phase. The above MRI features are helpful in distinguishing NRH from metastatic tumors.

Objective To investigate the value of flexible subtraction CE-Boost technique combined with low dosage contrast agents for CT pulmonary angiography(CTPA).Methods A total of 68 patients who would undergo CTPA examination due to suspected pulmonary embolism(PE)were prospectively enrolled and randomly divided into study group(n=34)and control group(n=34)using block randomization method.After injecting 25 ml contrast agents at a flow rate of 2.5 ml/s in study group or 50 ml contrast agents at a flow rate of 3.5 ml/s in control group,CTPA scanning were performed with identical parameters.For images in study group,hybrid iterative reconstruction was performed,followed by flexible subtraction CE-Boost post-processing to obtain CE-Boost CTPA.For images in control group,conventional CTPA was obtained with hybrid iterative reconstruction.Subjective and objective evaluations of image quality were compared between groups.Taken the final clinical diagnosis as standard,the accuracy rate of diagnosing PE were compared between groups.Results There were 7 cases of pulmonary artery main trunk PE and 15 cases of pulmonary lobe-level PE in study group,while in control group there were 8 cases and 17 cases.No statistical difference of subjective scores of CTPA was found between groups(P＞0.05).CT values of the main pulmonary artery,bilateral pulmonary artery trunks and lower lobes of both lungs,signal-to-noise ratio or contrast-to-noise ratio in CTPA were not significantly different between groups(all P＞0.05),while no significant difference of the accuracy rate of CTPA for diagnosing PE of pulmonary artery main trunk(100％[7/7]vs.100％[8/8])nor pulmonary lobe-level PE(86.67％[13/15]vs.88.24％[15/17])was detected between groups(all P＞0.05).Conclusion Flexible subtraction CE-Boost technique combined with low dosage contrast agents for CTPA could reduce contrast agent dosage without affecting image quality.

China's guidelines for the diagnosis and treatment of primary liver cancer(2024 edition)defines hepatocellular carcinoma(HCC)with diameter ≤ 1.0 cm as subcentimeter HCC(scHCC).The diagnostic criteria of scHCC are as follows:In HCC high-risk populations,after excluding lesions with extremely high T2 signal intensity and"target sign"features,the typical imaging features of HCC could be seen with the combination of extracellular contrast-enhanced MRI and hepatocyte-specific contrast-enhanced MRI,which is characterized by non-rim arterial phase hyperenhancement combined with washout in portal vein phase/delayed phase/transitional phase.MRI diagnosis of scHCC was focused and reviewed in this article.

Objective:To investigate the feasibility of ultra-low dose (ULD) CT pulmonary angiography (CTPA) combined with deep learning reconstruction (DLR) in the diagnosis of pulmonary embolism (PE).Methods:This cross-sectional study prospectively enrolled 100 patients with suspected PE who underwent CTPA examination in Zhongshan Hospital Fudan University, and Shanghai Geriatric Medical Center from April to July 2024, and were randomly divided into the routine dose (RD) group and ULD group according to block randomization. Effective dose (ED) were calculated. The noise index of RD group and ULD group was set to 10 and 20, respectively. Other scanning parameters and contrast agent injection protocol were the same. The CT images of RD group were reconstructed using hybrid iterative reconstruction (HIR), while ULD images were reconstructed with HIR and DLR (ULD-HIR subgroup and ULD-DLR subgroup). The image quality of the three groups of images was subjectively evaluated (overall image noise, pulmonary artery display) and objectively evaluated [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of the images] respectively. Finally, the diagnostic results of PE by the expert committee composed of three chief physicians were taken as the gold standard, and one physician with lower qualifications independently evaluated the diagnostic rate of PE in the three groups of images. Objective image quality parameters across the three groups were compared using ANOVA, with LSD post hoc test was used for multiple comparisons. Subjective scores among the three groups were analyzed using the Kruskal-Wallis H test, with Bonferroni corrected pairwise post hoc test was applied for multiple pairwise comparisons. Results:The ED in the RD group and ULD group were (2.7±0.5) mSv and (0.7±0.2) mSv, respectively, and the differences were statistically significant ( t=26.42, P<0.001). The overall differences in CT values of pulmonary arteries at all levels in the images of the RD group, the ULD-HIR subgroup, and the ULD-DLR subgroup were not statistically significant ( P>0.05).The RD group, ULD-HIR subgroup and ULD-DLR subgroup overall differences in SNR and CNR at all levels pulmonary arteries were statistically significant ( P<0.001), in which except for the differences in CNR and SNR values of the left pulmonary arterial trunk in the RD group and the ULD-HIR subgroup, and SNR values of basal segment pulmonary artery of the lower lobe of the left lung, which were not statistically significant ( P>0.05), the differences of the rest of the indexes in the pairwise comparisons between the groups were statistically significant ( P<0.05). The overall differences in the subjective scores of image pulmonary vascular display and image noise in the RD group, ULD-HIR subgroup and ULD-DLR subgroup were statistically significant ( P<0.001), except that the differences in the subjective scores of image pulmonary vascular display in the ULD-DLR subgroup were not statistically significant when compared with that of the RD group ( P>0.05) and that of the rest of the metrics in the between-groups two-by-two comparisons were all statistically significant ( P<0.05). The difference in diagnostic rates of PE in the pulmonary artery trunk, lobe and segmental levels in the images of the RD group, ULD-HIR subgroup and ULD-DLR subgroup was not statistically significant ( P>0.05). Conclusions:DLR can significantly reduce the radiation dose of CTPA examination. Even at ultra-low radiation dose, its image quality is still better than HIR reconstruction at conventional doses and preserve diagnostic accuracy of PE at the lobe level and segment level.

Objective:To explore the value of magnetic resonance examination in distinguishing invasive and non-invasive pancreatic solid pseudopapillary neoplasms (SPN).Methods:The clinical and MRI data of 167 patients with SPN who underwent surgery and were pathologically diagnosed at Zhongshan Hospital ,Fudan University from Oct 2013 to Oct 2023 were retrospectively analyzed.Results:There was no statistically significant difference between invasive and non-invasive SPN in terms of age, gender, clinical symptoms, laboratory tests, location, growth pattern, tumor size, relationship with the pancreas, bleeding, and pancreatic duct dilation ( P>0.05). However, there were statistically significant differences between the two groups in terms of tumor morphology, margins, capsule, cystic solid ratio, pancreatic atrophy, enhancement pattern, and enhancement features ( P<0.05). The area under the ROC curve for the combined indicators (tumor morphology, margins, capsule, cystic solid ratio, and pancreatic atrophy) was 0.679 (95% CI: 0.594-0.764), with a sensitivity of 73.7% and specificity of 70.9%. Conclusion:Magnetic resonance examination is helpful in distinguishing invasive and non-invasive pancreatic solid pseudopapillary neoplasms.

Objective:To investigate the feasibility and value of nomogram based on base line clinical and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) characteristics for pretreatment predicting the depth of myometrial invasion and tumor grade of endometrioid endometrial carcinoma (EEC).Methods:Preoperative baseline clinical characteristics and DCE-MRI characteristics of 194 EEC patients were prospectively collected at Obstetrics and Gynecology Hospital, Fudan University from October 2020 to January 2022 and used as a training set. Univariate analysis was conducted to compare baseline clinical characteristics and DCE-MRI quantitative parameters [including tumor volume, and mean, median, and standard deviation of volume transfer constant (K trans), rate constant (K ep), extravascular extracellular volume fraction (V e), and initial area under the enhancement curve (iAUC)] between patients with deep myometrial invasion (DMI) and those with superficial myometrial invasion (SMI), as well as between high-grade and low-grade EEC. Multivariate logistics regression analysis was used to identify independent predictors for the construction of nomogram. An independent external testing set comprising 127 EEC patients was retrospectively collected from Zhongshan Hospital, Fudan University and Zhongshan Hospital, Fudan University (Xiamen Branch). The area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA) were used for evaluating the model′s predictive performance and clinical net benefit, respectively. Results:(1) The depth of myometrial invasion: univariate analysis showed that in the training set, the EEC patients with DMI differed significantly from those with SMI in clinical characteristics including higher proportion of postmenopausal state and overweight [body mass index (BMI)≥25 kg/m2], and abnormal levels of serum cancer antigen (CA) 125, CA 199, and human epididymis protein 4 (HE4), and in DCE-MRI quantitative parameters including tumor volume, and median, mean, and standard deviation of K trans, median of V e, as well as median, mean, and standard deviation of iAUC (all P<0.05). Multivariate analysis showed that the patient′s menstrual status, BMI, CA 199, tumor volume, and mean of iAUC were independent predictors of the depth of myometrial invasion, and constructed the nomogram (recorded as Nomogram_1), achieving an AUC of 0.861 (95% CI: 0.803-0.919) in the training set. In the independent external testing set, the AUC was 0.876 (95% CI: 0.815-0.938), with corresponding sensitivity of 82.0%, specificity of 80.7%, accuracy of 81.1%, positive predictive value (PPV) of 65.3%, and negative predictive value (NPV) of 91.0% for predicting DMI. (2) The EEC grade: univariate analysis showed that in the training set, high-grade EEC patients differed significantly from low-grade EEC in clinical characteristics including patient′s age, the proportion of postmenopausal state and overweight, and abnormal levels of serum CA 125, and in DCE-MRI quantitative parameters including tumor volume, median, mean, and standard deviation of K trans, median and mean of V e, as well as median, mean, and standard deviation of iAUC (all P<0.05). Multivariate analysis showed that the patient′s menstrual status, BMI, tumor volume, and median of V e emerged as independent predictors of EEC grade, and constructed the nomogram (recorded as Nomogram_2), achieving an AUC of 0.845 (95% CI: 0.786-0.893) in the training set. While in the external testing set, the AUC was 0.819 (95% CI: 0.744-0.894), with corresponding sensitivity of 72.4%, specificity of 72.4%, accuracy of 72.4%, PPV of 43.8%, and NPV of 89.9% for predicting high-grade EEC. (3) The DCA curves demonstrated that both Nomogram_1 and Nomogram_2 yielded obvious positive clinical net benefits across a wide range of threshold probabilities. Conclusion:The nomogram based on pretreatment clinical and DCE-MRI characteristics has the potential to noninvasive predict the depth of myometrial invasion and grade of EEC, providing valuable reference information for clinical management decision-making.

Objective:To investigate the feasibility and value of nomogram based on base line clinical and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) characteristics for pretreatment predicting the depth of myometrial invasion and tumor grade of endometrioid endometrial carcinoma (EEC).Methods:Preoperative baseline clinical characteristics and DCE-MRI characteristics of 194 EEC patients were prospectively collected at Obstetrics and Gynecology Hospital, Fudan University from October 2020 to January 2022 and used as a training set. Univariate analysis was conducted to compare baseline clinical characteristics and DCE-MRI quantitative parameters [including tumor volume, and mean, median, and standard deviation of volume transfer constant (K trans), rate constant (K ep), extravascular extracellular volume fraction (V e), and initial area under the enhancement curve (iAUC)] between patients with deep myometrial invasion (DMI) and those with superficial myometrial invasion (SMI), as well as between high-grade and low-grade EEC. Multivariate logistics regression analysis was used to identify independent predictors for the construction of nomogram. An independent external testing set comprising 127 EEC patients was retrospectively collected from Zhongshan Hospital, Fudan University and Zhongshan Hospital, Fudan University (Xiamen Branch). The area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA) were used for evaluating the model′s predictive performance and clinical net benefit, respectively. Results:(1) The depth of myometrial invasion: univariate analysis showed that in the training set, the EEC patients with DMI differed significantly from those with SMI in clinical characteristics including higher proportion of postmenopausal state and overweight [body mass index (BMI)≥25 kg/m2], and abnormal levels of serum cancer antigen (CA) 125, CA 199, and human epididymis protein 4 (HE4), and in DCE-MRI quantitative parameters including tumor volume, and median, mean, and standard deviation of K trans, median of V e, as well as median, mean, and standard deviation of iAUC (all P<0.05). Multivariate analysis showed that the patient′s menstrual status, BMI, CA 199, tumor volume, and mean of iAUC were independent predictors of the depth of myometrial invasion, and constructed the nomogram (recorded as Nomogram_1), achieving an AUC of 0.861 (95% CI: 0.803-0.919) in the training set. In the independent external testing set, the AUC was 0.876 (95% CI: 0.815-0.938), with corresponding sensitivity of 82.0%, specificity of 80.7%, accuracy of 81.1%, positive predictive value (PPV) of 65.3%, and negative predictive value (NPV) of 91.0% for predicting DMI. (2) The EEC grade: univariate analysis showed that in the training set, high-grade EEC patients differed significantly from low-grade EEC in clinical characteristics including patient′s age, the proportion of postmenopausal state and overweight, and abnormal levels of serum CA 125, and in DCE-MRI quantitative parameters including tumor volume, median, mean, and standard deviation of K trans, median and mean of V e, as well as median, mean, and standard deviation of iAUC (all P<0.05). Multivariate analysis showed that the patient′s menstrual status, BMI, tumor volume, and median of V e emerged as independent predictors of EEC grade, and constructed the nomogram (recorded as Nomogram_2), achieving an AUC of 0.845 (95% CI: 0.786-0.893) in the training set. While in the external testing set, the AUC was 0.819 (95% CI: 0.744-0.894), with corresponding sensitivity of 72.4%, specificity of 72.4%, accuracy of 72.4%, PPV of 43.8%, and NPV of 89.9% for predicting high-grade EEC. (3) The DCA curves demonstrated that both Nomogram_1 and Nomogram_2 yielded obvious positive clinical net benefits across a wide range of threshold probabilities. Conclusion:The nomogram based on pretreatment clinical and DCE-MRI characteristics has the potential to noninvasive predict the depth of myometrial invasion and grade of EEC, providing valuable reference information for clinical management decision-making.

Objective:To investigate the feasibility of ultra-low dose (ULD) CT pulmonary angiography (CTPA) combined with deep learning reconstruction (DLR) in the diagnosis of pulmonary embolism (PE).Methods:This cross-sectional study prospectively enrolled 100 patients with suspected PE who underwent CTPA examination in Zhongshan Hospital Fudan University, and Shanghai Geriatric Medical Center from April to July 2024, and were randomly divided into the routine dose (RD) group and ULD group according to block randomization. Effective dose (ED) were calculated. The noise index of RD group and ULD group was set to 10 and 20, respectively. Other scanning parameters and contrast agent injection protocol were the same. The CT images of RD group were reconstructed using hybrid iterative reconstruction (HIR), while ULD images were reconstructed with HIR and DLR (ULD-HIR subgroup and ULD-DLR subgroup). The image quality of the three groups of images was subjectively evaluated (overall image noise, pulmonary artery display) and objectively evaluated [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of the images] respectively. Finally, the diagnostic results of PE by the expert committee composed of three chief physicians were taken as the gold standard, and one physician with lower qualifications independently evaluated the diagnostic rate of PE in the three groups of images. Objective image quality parameters across the three groups were compared using ANOVA, with LSD post hoc test was used for multiple comparisons. Subjective scores among the three groups were analyzed using the Kruskal-Wallis H test, with Bonferroni corrected pairwise post hoc test was applied for multiple pairwise comparisons. Results:The ED in the RD group and ULD group were (2.7±0.5) mSv and (0.7±0.2) mSv, respectively, and the differences were statistically significant ( t=26.42, P<0.001). The overall differences in CT values of pulmonary arteries at all levels in the images of the RD group, the ULD-HIR subgroup, and the ULD-DLR subgroup were not statistically significant ( P>0.05).The RD group, ULD-HIR subgroup and ULD-DLR subgroup overall differences in SNR and CNR at all levels pulmonary arteries were statistically significant ( P<0.001), in which except for the differences in CNR and SNR values of the left pulmonary arterial trunk in the RD group and the ULD-HIR subgroup, and SNR values of basal segment pulmonary artery of the lower lobe of the left lung, which were not statistically significant ( P>0.05), the differences of the rest of the indexes in the pairwise comparisons between the groups were statistically significant ( P<0.05). The overall differences in the subjective scores of image pulmonary vascular display and image noise in the RD group, ULD-HIR subgroup and ULD-DLR subgroup were statistically significant ( P<0.001), except that the differences in the subjective scores of image pulmonary vascular display in the ULD-DLR subgroup were not statistically significant when compared with that of the RD group ( P>0.05) and that of the rest of the metrics in the between-groups two-by-two comparisons were all statistically significant ( P<0.05). The difference in diagnostic rates of PE in the pulmonary artery trunk, lobe and segmental levels in the images of the RD group, ULD-HIR subgroup and ULD-DLR subgroup was not statistically significant ( P>0.05). Conclusions:DLR can significantly reduce the radiation dose of CTPA examination. Even at ultra-low radiation dose, its image quality is still better than HIR reconstruction at conventional doses and preserve diagnostic accuracy of PE at the lobe level and segment level.