Magnetic Resonance Imaging (MRI) is one of the leading modalities for medical imaging, providing excellent softtissue contrast without exposure to ionizing radiation. Despite continuing advances in MRI, long scan times remain a major limitation in clinical applications. Parallel imaging is a technique for scan time acceleration in MRI, which utilizes the spatial variations in the reception profiles of receiver coil arrays to reconstruct images from undersampled Fourier space, i.e. K-space. One of the most commonly used parallel imaging techniques employs interpolation of missing k-space information by using linear shiftinvariant convolutional kernels. These kernels are trained on a limited amount of autocalibration signal (ACS) for each scan. We propose a novel method for parallel imaging,Robust Artificialneural-networks for k -space Interpolation (RAKI), which uses scan-specific convolutional neural networks (CNNs) to perform improved k-space interpolation. Three-layer CNNs are trained using only scan-specific ACS data, alleviating the need for large training databases. The proposed method was tested in ultra-high resolution brain MRI and quantitative cardiac MRI, acquired with various acceleration rates. Improved noise resilience as compared to existing parallel imaging methods was observed for high acceleration rates or in the presence of low signal-tonoise ratio (SNR). Furthermore, RAKI successfully reconstructed images for quantitative cardiac MRI, even when using the same CNN across images with varying contrasts. These results indicate that RAKI achieves improved noise performance without overfitting to specific image contents, and offers great promise for improved acceleration in a wide range of MRI applications.
|Original language||English (US)|
|Title of host publication||2018 International Joint Conference on Neural Networks, IJCNN 2018 - Proceedings|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|State||Published - Oct 10 2018|
|Event||2018 International Joint Conference on Neural Networks, IJCNN 2018 - Rio de Janeiro, Brazil|
Duration: Jul 8 2018 → Jul 13 2018
|Name||Proceedings of the International Joint Conference on Neural Networks|
|Other||2018 International Joint Conference on Neural Networks, IJCNN 2018|
|City||Rio de Janeiro|
|Period||7/8/18 → 7/13/18|
Bibliographical noteFunding Information:
This work was partially supported by NIH R00HL111410, NIH P41EB015894, NIH U01EB025144, NSF CAREER CCF-1651825.