One for Multiple: Physics-informed Synthetic Data Boosts Generalizable Deep Learning for Fast MRI Reconstruction

Magnetic resonance imaging (MRI) is a principal radiological modality that provides radiation-free, abundant, and diverse information about the whole human body for medical diagnosis, but suffers from prolonged scan time. The scan time can be significantly reduced through k-space undersampling but the introduced artifacts need to be removed in image reconstruction. Although deep learning (DL) has emerged as a powerful tool for image reconstruction in fast MRI, its potential in multiple imaging scenarios remains largely untapped. This is because not only collecting large-scale and diverse realistic training data is generally costly and privacy-restricted, but also existing DL methods are hard to handle the practically inevitable mismatch between training and target data. Here, we present a Physics-Informed Synthetic data learning framework for Fast MRI, called PISF, which is the first to enable generalizable DL for multi-scenario MRI reconstruction using solely one trained model. For a 2D image, the reconstruction is separated into many 1D basic problems and starts with the 1D data synthesis, to facilitate generalization. We demonstrate that training DL models on synthetic data, integrated with enhanced learning techniques, can achieve comparable or even better in vivo MRI reconstruction compared to models trained on a matched realistic dataset, reducing the demand for real-world MRI data by up to 96%. Moreover, our PISF shows impressive generalizability in multi-vendor multi-center imaging. Its excellent adaptability to patients has been verified through 10 experienced doctors' evaluations. PISF provides a feasible and cost-effective way to markedly boost the widespread usage of DL in various fast MRI applications, while freeing from the intractable ethical and practical considerations of in vivo human data acquisitions.Comment: 22 pages, 9 figures, 1 tabl

A 200-MS/s 10-Bit SAR ADC Applied in WLAN Systems

This paper introduces a new high-performance successive approximation register (SAR) analog-to-digital converter (ADC) designed for high-speed and low-power wireless local area network (WLAN) applications using a SMIC 55 nm 1p8m CMOS process. The design employs several innovative techniques, including an improved bootstrap switch with high linearity, a 4-reference voltage method to minimize capacitive digital-to-analog converter (CDAC) mismatch, a kickback-canceling comparator to eliminate kick-back noise, and redundant design-assisted window-opening SAR logic to decrease conversion time. Experimental results reveal that the proposed ADC achieves an impressive signal-to-noise and distortion ratio (SNDR) of 55.3 dB and a spurious-free dynamic range (SFDR) of 66.6 dB at a sampling rate of 200 MHz with Nyquist frequency input while consuming a power of 2.8 mW at a 1.2 V power supply. This corresponds to a figure-of-merit (FoM) value of 29 fJ/conversion-step. Thanks to the incorporation of the 4-reference voltage method, the ADC demonstrates a significant area advantage compared to other designs with similar FOM values utilizing more advanced processes, occupying a mere 0.008 mm2 of core area

Why Coins Turned Round the World Over? A Critical Analysis of the Origins and Transmission of Ancient Metallic Money

The inspiration behind the pre-modern bronze round coinage standardised across China by the First Emperor of Qin in the 3rd century BC have remained fairly obscure and are still a contentious issue. We demonstrate in this article that the various theories arguing for an exclusively endogenous impetus behind the spread and development of Chinese round coinage vouched for by many scholars in either East Asia or the West all carry inherent contradictions. In contrast, circumstantial and archaeological evidence in support of partly exogenous origins are mounting. Evidence from the Middle East points to the early invention and wide circulation of round coinage in Lydia, Greece and the Achaemenid Empire. The expansion of the Persians into India in the 6th century BC and the later incursions by Alexander and the Greco-Bactrians in the fourth and third centuries BC all facilitated and may have decisively contributed to India's adoption of round coinage. Similarly, the flow of ideas, artistic motifs and metallurgic knowhow from West Asia to China via Central Asia had occurred much earlier than the 3rd century BC. Active adoption of foreign (Central Eurasian steppe) customs in the fourth century BC is recorded in Chinese pre-imperial records and confirmed by recent archaeological findings across Eurasia. Ongoing archaeological work in China's western provinces could further highlight this ancient phase of globalization that, quite literally, still shapes our most fundamental grasp of money