Human prostate MRI at ultrahigh-performance gradient: A feasibility study
Ante Zhu, Matthew Tarasek, Yihe Hua, Eric Fiveland, Stephan E. Maier, Yousef Mazaheri, Maggie Fung, Carl-Fredrik Westin, Desmond T. B. Yeo, Filip Szczepankiewicz, Clare Tempany, Oguz Akin, Thomas K. F. Foo
Abstract
Purpose
To demonstrate the technical feasibility and the value of ultrahigh-performance gradient in imaging the prostate in a 3T MRI system.
Methods
In this local institutional review board–approved study, prostate MRI was performed on 4 healthy men. Each subject was scanned in a prototype 3T MRI system with a 42-cm inner-diameter gradient coil that achieves a maximum gradient amplitude of 200 mT/m and slew rate of 500 T/m/s. PI-RADS V2.1–compliant axial T2-weighted anatomical imaging and single-shot echo planar DWI at standard gradient of 70 mT/m and 150 T/m/s were obtained, followed by DWI at maximum performance (i.e., 200 mT/m and 500 T/m/s). In comparison to state-of-the-art clinical whole-body MRI systems, the high slew rate improved echo spacing from 1020 to 596 μs and, together with a high gradient amplitude for diffusion encoding, TE was reduced from 55 to 36 ms.
Results
In all 4 subjects (waist circumference = 81–91 cm, age = 45–65 years), no peripheral nerve stimulation sensation was reported during DWI. Reduced image distortion in the posterior peripheral zone prostate gland and higher signal intensity, such as in the surrounding muscle of high-gradient DWI, were noted.
Conclusion
Human prostate MRI at simultaneously high gradient amplitude of 200 mT/m and slew rate of 500 T/m/s is feasible, demonstrating that improved gradient performance can address image distortion and T2 decay–induced SNR issues for in vivo prostate imaging.