A Miniaturized 3-D-MRI Scanner Featuring an HV-SOI ASIC and Achieving a 10 × 8 × 8 mm<sup>3</sup> Field of View
Shuhao Fan, Qi Zhou, Ka‐Meng Lei, Pui‐In Mak, Rui P. Martins
Abstract
This article describes a miniaturized 3-D magnetic resonance imaging (3-D-MRI) scanner empowered by a high-voltage silicon-on-insulator (HV-SOI) CMOS application-specific integrated circuit (ASIC). With a 0.52-T permanent magnet and integrating the electronics onto a 6-mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> silicon chip, the scanner weighs 42 kg and provides a field of view (FOV) of 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 8 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> for probing the internal structure of a wide variety of objects non-invasively. The ASIC features a mixed-transistor HV-enabled transmitter (TX) to enhance the output-current deliverability (1.24 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{A}_{\mathrm {pp}}$ </tex-math></inline-formula> to a 1- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> load), a low-noise receiver (RX) exploiting the dynamic-threshold MOSFET (DTMOS), and deep trench isolation (DTI) for a better noise performance and substrate noise immunity. The achieved RX input-referred noise of 0.63 nV/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula> Hz significantly enhances the SNR of the image and enables fast image acquisition. We also introduce a digital-to-analog converter (DAC)-based gradient controller to compose the MRI sequences for 3-D spatial encoding. The key functionality of the 3-D-MRI scanner is exhibited with two fruit samples: raspberry and pomegranate, achieving a resolution of 110 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 117 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 250 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}^{3}$ </tex-math></inline-formula> , in 0.17 min.