Correlations between DKI and DWI with Ki-67 in gastric adenocarcinoma.

BACKGROUND: Diffusion kurtosis imaging (DKI) has been applied for gastric adenocarcinoma. Correlations between its parameters and Ki-67 are unclear. PURPOSE: To investigate the correlation between DKI and diffusion-weighted imaging (DWI) parameters with the Ki-67 index in gastric adenocarcinoma. MATERIAL AND METHODS: A total of 54 patients with gastric adenocarcinoma were enrolled in the study and underwent DWI and DKI at 3.0-T MRI before surgery. Based on the settings of the regions of interest, the DWI and DKI parameters (including apparent diffusion coefficient [ADC], diffusion kurtosis [K], and diffusion coefficient [DK]) of each patient's gastric adenocarcinoma were measured and calculated. The participants were divided into two groups (low Ki-67 group and high Ki-67 groups). The intraclass correlation coefficient (ICC) and independent-sample t-test were used to compare differences in each parameter between two groups. Spearman's correlation coefficient was calculated to determine the correlation between Ki-67 and the parameters. Each parameter was compared using the area under the receiver operating characteristic curve. All parameters were included in the multivariate logistic regression analysis to explore the relationship between each parameter and high Ki-67 index. RESULTS: ADC and DK were negatively relevant with Ki-67 and K was positively relevant with Ki-67 in gastric adenocarcinoma. ADC, DK, and K had diagnostic efficiency in differentiating the low Ki-67 group from the high Ki-67 group. A higher K value independently predicted a high Ki-67 status. CONCLUSION: DWI and DKI reflected the proliferative characteristics of gastric adenocarcinoma. K was the strongest independent factor for predicting high Ki-67 status.

From study abroad to study at home: Spontaneous neuronal activity predicts depressive symptoms in overseas students during the COVID-19 pandemic.

The objective of this study was to evaluate symptoms of depression and anxiety as well as changes in spontaneous neuronal activity in college students studying abroad during the coronavirus 2019 (COVID-19) pandemic. We examined functional brain changes using resting-state functional magnetic resonance imaging (fMRI), the amplitude of low-frequency fluctuations (ALFF), and regional homogeneity (ReHo) in overseas students with enforced isolation due to the COVID-19 pandemic. Additionally, emotional assessments were administered to determine the severity of depression and anxiety. The questionnaire results showed that anxiety and depressive symptoms differed between overseas students (i.e., those attending an overseas college virtually) and local students (i.e., those attending a local college in person). The fMRI data revealed higher ALFF values in the bilateral superior medial frontal gyrus, bilateral pre-central gyrus, left insula, and left superior temporal gyrus as well as lower ALFF values in the bilateral paracentral lobule (supplementary motor area) in overseas students. Moreover, ReHo analysis also revealed significant differences between overseas students and local students. Compared with local students, overseas students showed significantly increased ReHo in the right inferior frontal and superior temporal gyri and decreased ReHo in the bilateral paracentral lobule, bilateral superior medial frontal gyrus (supplementary motor area), and bilateral pre-central gyrus. In addition, in overseas students, altered ReHo in the cluster including the left superior and medial frontal gyri, pre-central gyrus, and paracentral lobule was significantly positively correlated with Self-Rating Depression Scale scores. Thus, spontaneous brain activity in overseas students changed during the COVID-19 pandemic. This change in brain function might be related to depression and anxiety symptoms. These results suggest that mental health services are needed to decrease the risk of anxiety and depression among college students studying abroad during the COVID-19 pandemic.

T1 mapping and reduced field-of-view DWI at 3.0 T MRI for differentiation of thyroid papillary carcinoma from nodular goiter.

BACKGROUND: Reduced field-of-view diffusion-weighted imaging (rFOV-DWI) could be proved to quantitatively identify papillary thyroid carcinoma (PTC) and there is no literature regarding the use of T1 mapping to distinguish nodular goiter (NG) from PTC. PURPOSE: To compare T1 mapping with rFOV-DWI in differentiating NG and PTC. STUDY TYPE: Prospective study. POPULATIONS: Ninety-five hospitalized patients with thyroid nodules were included in the research. SEQUENCE: All subjects underwent T1-weighted imaging, T2-weighted imaging, rFOV-DWI and T1-mapping sequences. ASSESSMENT: The apparent diffusion coefficient (ADC) and T1 values of each thyroid nodule were measured, respectively. According to pathological results, the thyroid nodules were divided into two groups: Group 1 (NG) and Group 2 (PTC). STATISTICAL TESTS: An independent sample t test was used to evaluate the differences of ADC and T1 between the two groups. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic efficiency of T1, ADC, Thyroid Imaging Reporting and Data System (TI-RADS) and T1 and ADC. RESULTS: The T1 and ADC values of nodular goiter were both higher than those of PTC (p < 0.05). The area under the ROC curve (AUC) values of T1 and ADC were significantly higher than that of T1 or ADC alone (p < 0.05). The AUC value of T1 and ADC was as same as that of TI-RADS. CONCLUSION: The combination of T1 mapping and rFOV-DWI could effectively differentiate NG from PTC. And it has at least the same diagnostic value as the ultrasound-based TI-RADS classification.