How to Get the Most from Your MR Machine for Prostate Imaging
Moon Hyung Choi1
1Catholic University of Korea Eunpyeong St Mary's Hospital:, Seoul, Korea, Republic of

Synopsis

Keywords: Body: Pelvis

Given the increasing number of prebiopsy prostate MRIs and the changing role of prostate MRI, we would like to discuss ways to obtain images that are helpful for interpretation while maintaining image quality and acquiring them quickly. Compressed sensing (CS) and deep learning-based image reconstruction (DLR) are used to improve the speed and quality of MRI imaging. For diffusion weighted imaging, multi-shot or segmented DWI and calculated high b value DWI images are useful. It is essential to stay updated on new techniques, to get the most out of MRI machines.

Prostate MRI is considered the best imaging modality for evaluating the prostate gland. Prebiopsy MRI has become widely used due to multiple research findings showing that performing a tissue biopsy after a prostate MRI can detect more clinically significant cancers and fewer clinically insignificant cancers [1, 2]. As a result, the number of prostate MRI procedures has increased, and the purpose of prostate MRI has changed. While prostate MRI in patients diagnosed with prostate cancer is primarily intended to confirm the location, size, and stage of the cancer to establish treatment plans, prebiopsy prostate MRI aims to identify suspected lesions of prostate cancer and perform targeted biopsies in those areas. The Prostate Imaging-Reporting and Data System (PI-RADS) version 2.1 recommends using multiparametric MRI, which includes T2-weighted imaging, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging, as the standard protocol [3]. The use of DCE MRI is controversial as it is only used for lesions in the peripheral zone with PI-RADS classification 3 on T2-weighted imaging [4, 5]. However, DCE MRI improves the sensitivity of MRI, and biparametric MRI without DCE MRI is recommended for selected clinical indications [3]. Thus, there is a need to acquire prostate MRI more quickly while preserving image quality, obtaining prostate MRI with better image quality, or improving the accuracy of MRI interpretation. Many techniques are utilized to improve prostate cancer diagnosis by enhancing image quality and accelerating image acquisition. Compressed sensing (CS) is a technique used in MRI to reduce the amount of data acquired during the scan process, resulting in faster scan times [6]. It works by exploiting the sparsity of the signal in the image, allowing for the reconstruction of a high-quality image from a smaller amount of data. This is achieved by acquiring random subsets of k-space data and using advanced reconstruction algorithms to fill in the missing information. Compressed sensing (CS) is employed in dynamic contrast-enhanced (DCE) MRI of the prostate gland as a component of golden-angle radial sparse parallel (GRASP) imaging, enabling shorter temporal resolution. In. Compressed sensing (CS) is employed in dynamic contrast-enhanced (DCE) MRI of the prostate gland as a component of golden-angle radial sparse parallel (GRASP) imaging, enabling shorter temporal resolution [7, 8]. The use of GRASP with shorter temporal resolution (2.5 seconds) in a study was found to be beneficial in differentiating prostate cancer from normal tissue compared to conventional DCE MRI with 10-second temporal resolution [9]. The use of CS can enable the acquisition of 3D isotropic imaging with high spatial resolution in a clinically acceptable scan time [10] . Deep learning-based image reconstruction (DLR) is a novel approach to improve the speed and quality of MRI imaging. DLR uses artificial neural networks to generate high-quality images from the acquired low-quality images (usually accelerated MRI) or to improve the image quality of conventionally obtained images. The benefit of DLR has been explored in both T2-weighted imaging and diffusion-weighted imaging of the prostate gland [11-15]. In prostate multiparametric MRI, DWI is considered most important. Multi-shot or segmented DWI is useful for better image quality. Zoomed EPI decreases the field of view to reduce image distortion [16-18]. In PIRADS v2.1, it is recommended to use a b value of 1400 or higher in diffusion-weighted imaging (DWI) to aid in the differentiation of prostate cancer from other areas. High b value DWI images are useful because they highlight differences in diffusion within tissues more strongly, but they come with the drawback of longer scan times and lower signal-to-noise ratio (SNR). Calculated high B value DWI images are useful to highlight the diffusion-restricted area without additional image acquisition time [19, 20]. It is essential to stay updated on new techniques, discuss the benefits of new MRI techniques with colleagues, and optimize their use to get the most out of MRI machines. In clinical practice, effective communication with radiographers is also crucial.

Acknowledgements

No acknowledgement found.

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Proc. Intl. Soc. Mag. Reson. Med. 31 (2023)