Magnetic Resonance Spectroscopy for Cervical Cancer: Review and Potential Prognostic Applications

Abstract

This review article investigates the utilization of MRS in the setting of cervical cancer. A variety of different techniques have been used in this space including single-voxel techniques such as point-resolved spectroscopy (PRESS) and stimulated echo acquisition mode spectroscopy (STEAM). Furthermore, the experimental parameters for these acquisitions including field strength, repetition times (TR), and echo times (TE) vary greatly. This study critically examines eleven MRS studies that focus on cervical cancer. Out of the eleven studies, ten studies utilized PRESS acquisition, while the remaining study used STEAM acquisition. These studies generally showed that the choline signal is altered in cervical cancer (4/11 studies), the lipid signal is generally increased in cervical cancer or the lipid distribution is changed (5/11 studies), and that diffusion-weighted imaging (DWI) can quantitatively detect lower apparent diffusion coefficient (ADC) values in cervical cancer (2/11 studies). Two studies also investigated the role of MRS for monitoring treatment response and demonstrated mixed results regarding choline signal, and one of these studies showed increased lipid signal for non-responders. There are several new MRS technologies that have yet to be implemented for cervical cancer including advanced spectroscopic imaging and artificial intelligence, and those technologies are also discussed in the article.

Keywords: MRS; NMR; biomarkers; cervical cancer; choline; fatty acids; lipids.

Figure 1

(A) Single voxel localization is achieved by acquiring data from the intersection of slice-selective pulses applied in orthogonal directions (black, green, and red) (B) The STEAM localization technique is shown, which utilizes three 90° pulses. (C) The PRESS localization technique is displayed, which utilizes a 90° excitation pulse followed by two 180° pulses. In the figure, TE is the echo time and TM is the mixing time, and these values can range from a few milliseconds to hundreds of milliseconds. STEAM forms a stimulated echo, whereas PRESS forms a spin echo, which can result in different T2 weighting of the spectra. The black, green, and red can be iterated during an experiment to yield MR spectroscopic imaging.