NMR CAPIBarA: Proof of Principle of a Low-Field Unilateral Magnetic Resonance System for Monitoring of the Placenta during Pregnancy

Robert H Morris ,Christophe L Trabi,Michael I Newton,Najlaa K Almazrouei

doi:10.3390/app10010162

Robert H Morris , Christophe L Trabi + Show 2 more

Open Access

https://doi.org/10.3390/app10010162

Copy DOI

Journal: Applied Sciences	Publication Date: Dec 24, 2019
Citations: 2	License type: CC BY 4.0

Affiliation: Nottingham Trent University

Abstract

A growing body of literature shows that the transverse relaxation times of the placenta change during pregnancy and may be an early indicator of disease. Magnetic resonance imaging (MRI) of pregnant women is not, however, currently used frequently despite this evidence. One significant barrier to adoption is the cost of undertaking an MRI scan and the over utilization of existing equipment. Low-field nuclear magnetic resonance (NMR) offers a low-cost alternative, capable of measuring transverse relaxation in a single point in space. Ultrasound imaging (US) is routinely used at several points during pregnancy but is not capable of early detection of pre-eclampsia, for example. It does, however, provide a technique that is capable of locating the placenta with ease. In combination with a single point low-field measurement, localised with ultrasound imaging allows access to this exciting technique without the need for an expensive traditional MRI. In this work, we present a unilateral system (NMR CAPIBarA), operating at a magnetic field of only 18mT, which measures transverse relaxation times at distances from its surface equivalent to the positioning of a human placenta. Data are presented to characterise the system using relation time standards covering the full transverse relaxation time range relevant for the developing placenta, which are also measured on a 1.5 T clinical MRI scanner.

Highlights

The average cost for a magnetic resonance imaging (MRI) scan has been suggested to be in excess of $2500 [1]
1998 [3], it had been reported that the nuclear magnetic resonance (NMR) relaxation parameter, known as the transverse relaxation time of the placenta decreases through pregnancy
The transmit efficiency is the the limiting factor in the sensitive volume, which may, be an advantage for practical uses limiting factoryielding in the sensitive volume, which may, be aninadvantage practical such uses as of of the system a small sensitive spot that is well visualised concurrentfor modalities the system yielding small sensitive spot that is well visualised in concurrent modalitiesalthough such as ultrasound imaging.aAt present, the system is only capable of reaching anterior placentae ultrasound imaging

Summary

Introduction

The average cost for a magnetic resonance imaging (MRI) scan has been suggested to be in excess of $2500 [1]. In comparison to the average cost of an ultrasound at $263 [2], from a cost perspective alone it is unsurprising that the routine monitoring of placental health is undertaken throughout a pregnancy using ultrasound. Reveals little about many diseases of the placenta until they have progressed. 1998 [3], it had been reported that the nuclear magnetic resonance (NMR) relaxation parameter, known as the transverse relaxation time of the placenta decreases through pregnancy. Ultrasound scans have become routine during pregnancy in many countries around the world, as they are affordable in most hospitals and can be purchased in some quantity in an average obstetrics department. If a simple add-on to the ultrasound could be developed to provide a measure of

Methods

Results

Discussion

Conclusion