Comparative analysis of the image quality and diagnostic performance of the zooming technique with diffusion-weighted imaging using different b-values for thyroid papillary carcinomas and benign nodules.

Objective: To compare image quality and diagnostic performance using different b-values for the zooming technique with diffusion-weighted imaging (ZOOMit-DWI) in thyroid nodules. Materials and methods: A total of 51 benign thyroid nodules and 50 thyroid papillary carcinomas were included. ZOOMit-DWI was performed with b-values of 0, 500, 1000, 1500 and 2000 s/mm2. The sharpness was evaluated as subjective index. The signal intensity ratio (SIR), signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) were measured as objective indices. Pairwise comparisons were performed among the different b-value groups using the Friedman test. A receiver operating characteristic curve of the ADC value was used to evaluate diagnostic performance. The DeLong test was used to compare diagnostic effectiveness among the different b-value groups. Results: In both the papillary carcinoma group (P = 0.670) and the benign nodule group (P = 0.185), the sharpness of nodules was similar between b-values of 1000 s/mm2and 1500 s/mm2. In the papillary carcinoma group, the SIRnodule was statistically higher in DWI images with a b-value of 1500 s/mm2than in DWI images with b-values of 500 s/mm2(P = 0.004), 1000 s/mm2(P = 0.002), and 2000 s/mm2(P = 0.003). When the b-values were 1500 s/mm2(P = 0.008) and 2000 s/mm2(P = 0.009), the SIRnodule significantly differed between the papillary carcinoma group and the benign nodule group. When b = 500 s/mm2, the ADC had an AUC of 0.888. When b = 1000 s/mm2, the ADC had an AUC of 0.881. When b = 1500 s/mm2, the ADC had an AUC of 0.896. When b = 2000 s/mm2, the ADC had an AUC of 0.871. The DeLong test showed comparable diagnostic effectiveness among the different b-value groups except for between b-values of 2000 s/mm2and 1500 s/mm2, with a b-value of 2000 s/mm2showing lower effectiveness. Conclusion: This study suggests that 1500 s/mm2may be a suitable b-value to differentiate benign and malignant thyroid nodules in ZOOMit-DWI images, which yielded better image quality.

N-acetyltransferase NAT10 controls cell fates via connecting mRNA cytidine acetylation to chromatin signaling.

Cell fate transition involves dynamic changes of gene regulatory network and chromatin landscape, requiring multiple levels of regulation, yet the cross-talk between epitranscriptomic modification and chromatin signaling remains largely unknown. Here, we uncover that suppression of N-acetyltransferase 10 (NAT10), the writer for mRNA N4-acetylcytidine (ac4C) modification, can notably affect human embryonic stem cell (hESC) lineage differentiation and pluripotent reprogramming. With integrative analysis, we identify that NAT10-mediated ac4C modification regulates the protein levels of a subset of its targets, which are strongly enriched for fate-instructive chromatin regulators, and among them, histone chaperone ANP32B is experimentally verified and functionally relevant. Furthermore, NAT10-ac4C-ANP32B axis can modulate the chromatin landscape of their downstream genes (e.g., key regulators of Wnt and TGFß pathways). Collectively, we show that NAT10 is an essential regulator of cellular plasticity, and its catalyzed mRNA cytidine acetylation represents a critical layer of epitranscriptomic modulation and uncover a previously unrecognized, direct cross-talk between epitranscriptomic modification and chromatin signaling during cell fate transitions.