An Uncertainty Aided Framework for Learning based Liver T1ρT_1\rho Mapping and Analysis

Objective: Quantitative $T_1\rho$ imaging has potential for assessment of biochemical alterations of liver pathologies. Deep learning methods have been employed to accelerate quantitative $T_1\rho$ imaging. To employ artificial intelligence-based quantitative imaging methods in complicated clinical environment, it is valuable to estimate the uncertainty of the predicated $T_1\rho$ values to provide the confidence level of the quantification results. The uncertainty should also be utilized to aid the post-hoc quantitative analysis and model learning tasks. Approach: To address this need, we propose a parametric map refinement approach for learning-based $T_1\rho$ mapping and train the model in a probabilistic way to model the uncertainty. We also propose to utilize the uncertainty map to spatially weight the training of an improved $T_1\rho$ mapping network to further improve the mapping performance and to remove pixels with unreliable $T_1\rho$ values in the region of interest. The framework was tested on a dataset of 51 patients with different liver fibrosis stages. Main results: Our results indicate that the learning-based map refinement method leads to a relative mapping error of less than 3% and provides uncertainty estimation simultaneously. The estimated uncertainty reflects the actual error level, and it can be used to further reduce relative $T_1\rho$ mapping error to 2.60% as well as removing unreliable pixels in the region of interest effectively. Significance: Our studies demonstrate the proposed approach has potential to provide a learning-based quantitative MRI system for trustworthy $T_1\rho$ mapping of the liver

Accuracy, Reliability, and Comprehensiveness of ChatGPT-Generated Medical Responses for Patients With Nonalcoholic Fatty Liver Disease

: Nonalcoholic fatty liver disease (NAFLD) is an increasing global health problem and is expected to become the leading indication for liver transplantation.1 There are no approved NAFLD-specific pharmacotherapies, and lifestyle modification is the primary recommended therapy.2 Innovative approaches to facilitate the implementation and long-term maintenance of lifestyle changes are needed to address the challenging and complex nature of the management of NAFLD, which recently was renamed as metabolic dysfunction-associated steatotic liver disease, to overcome the limitations and stigma of the previous name.3,4 Artificial intelligence (AI)-powered chatbots have been shown to provide effective personalized support and education to patients, with the potential to complement health care resources. The OpenAI Foundation's AI chatbot, Chat Generative Pretrained Transformer (ChatGPT), has attracted worldwide attention for its remarkable performance in question-answer tasks.5-7 This study evaluated the accuracy, completeness, and comprehensiveness of chatGPT's responses to NAFLD-related questions, with the aim of assessing its performance in addressing patients' queries about the disease and lifestyle behaviors

Bacterial Microbiota Profiling in Gastritis without Helicobacter pylori Infection or Non-Steroidal Anti-Inflammatory Drug Use

Recent 16S ribosomal RNA gene (rRNA) molecular profiling of the stomach mucosa revealed a surprising complexity of microbiota. Helicobacter pylori infection and non-steroidal anti-inflammatory drug (NSAID) use are two main contributors to gastritis and peptic ulcer. However, little is known about the association between other members of the stomach microbiota and gastric diseases. In this study, cloning and sequencing of the 16S rRNA was used to profile the stomach microbiota from normal and gastritis patients. One hundred and thirty three phylotypes from eight bacterial phyla were identified. The stomach microbiota was found to be closely adhered to the mucosa. Eleven Streptococcus phylotypes were successfully cultivated from the biopsies. One to two genera represented a majority of clones within any of the identified phyla. We further developed two real-time quantitative PCR assays to quantify the relative abundance of the Firmicutes phylum and the Streptococcus genus. Significantly higher abundance of the Firmicutes phylum and the Streptococcus genus within the Firmicutes phylum was observed in patients with antral gastritis, compared with normal controls. This study suggests that the genus taxon level can largely represent much higher taxa such as the phylum. The clinical relevance and the mechanism underlying the altered microbiota composition in gastritis require further functional studies

Performance of Noninvasive Tests of Fibrosis Among Asians, Hispanic, and non-Hispanic Whites in the STELLAR Trials

BACKGROUND & AIMS: The effect of race on routinely available noninvasive tests of fibrosis is incompletely under stood. This study evaluated the performance of noninvasive tests among white and Asian pa tients in the STELLAR trials (NCT03053050 and NCT03053063), which evaluated selonsertib in patients with advanced (F3-F4) fibrosis due to nonalcoholic steatohepatitis (NASH). METHODS: Baseline liver biopsies were centrally read using the NASH Clinical Research Network system, and 4 noninvasive tests (Nonalcoholic fatty liver disease fibrosis score [NFS], Fibrosis-4 index [FIB-4], Enhanced Liver Fibrosis test [ELF], and liver stiffness by vibration-controlled transient elastography) were measured. The performance of these tests to discriminate advanced fibrosis was evaluated using areas under the receiver operating characteristics curves with 5-fold cross validation repeated 100 times. RESULTS: Among 3207 patients screened with evaluable liver histology, 2281 were whites and 762 were Asians. Seventy-two percent of whites and 67% of Asians had advanced fibrosis. The areas under the receiver operating characteristics curves of the noninvasive tests for advanced fibrosis were similar in whites and Asians: 0.73 and 0.75 for NFS, 0.78 and 0.80 for FIB-4, 0.79 and 0.81 for ELF, and 0.80 and 0.83 for liver stiffness, respectively. At the published cutoffs, the tests had similar sensitivities and specificities in the 2 groups. However, the sensitivities of NFS, FIB-4, and ELF were low in both white and Asian patients younger than 40 years. CONCLUSIONS: In the global phase III STELLAR trials, the diagnostic performance of routinely available noninvasive tests for the detection of advanced fibrosis due to NASH was acceptable and similar between white and Asian patients