MRI of the lung (1/3): methods

Abstract

Proton magnetic resonance imaging (MRI) has recently emerged as a clinical tool to image the lungs. This paper outlines the current technical aspects of MRI pulse sequences, radiofrequency (RF) coils and MRI system requirements needed for imaging the pulmonary parenchyma and vasculature. Lung MRI techniques are presented as a "technical toolkit", from which MR protocols will be composed in the subsequent papers for comprehensive imaging of lung disease and function (parts 2 and 3). This paper is pitched at MR scientists, technicians and radiologists who are interested in understanding and establishing lung MRI methods. Images from a 1.5 T scanner are used for illustration of the sequences and methods that are highlighted. Main Messages • Outline of the hardware and pulse sequence requirements for proton lung MRI • Overview of pulse sequences for lung parenchyma, vascular and functional imaging with protons • Demonstration of the pulse-sequence building blocks for clinical lung MRI protocols.

Fig. 1

1.5 T vs 3 T anatomical image SSFSE, bSSFP and SPGR

Fig. 2

Balanced steady state free precession (bSSFP) images at full inspiration and full expiration

Fig. 3

T2 filter for SSFSE

Fig. 4

Body coil vs array coil

Fig. 5

SSFSE with and without parallel imaging

Fig. 6

UTE at 1.5 T in a patient with interstitial lung disease

Fig. 7

Breath-hold CE pulmonary MRA

Fig. 8

Time-resolved bolus passage TRICKS data set

Fig. 9

Parametric maps of perfusion

Fig. 10

A series of images acquired during inversion recovery at different inversion times with a Look-Locker sequence and the resulting T1 maps obtained breathing air and oxygen