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Magn Reson Med. 2017 Mar;77(3):1284-1295. doi: 10.1002/mrm.26212. Epub 2016 Mar 12.

Retrospective respiratory self-gating and removal of bulk motion in pulmonary UTE MRI of neonates and adults.

Author information

1
Center for Pulmonary Imaging Research, Division of Pulmonary Medicine and Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
2
Department of Physics, Washington University in St. Louis, St. Louis, Missouri, USA.
3
Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.
4
Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
5
Department of Physics, University of Cincinnati, Cincinnati, Ohio, USA.
6
Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
7
Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.

Abstract

PURPOSE:

To implement pulmonary three-dimensional (3D) radial ultrashort echo-time (UTE) MRI in non-sedated, free-breathing neonates and adults with retrospective motion tracking of respiratory and intermittent bulk motion, to obtain diagnostic-quality, respiratory-gated images.

METHODS:

Pulmonary 3D radial UTE MRI was performed at 1.5 tesla (T) during free breathing in neonates and adult volunteers for validation. Motion-tracking waveforms were obtained from the time course of each free induction decay's initial point (i.e., k-space center), allowing for respiratory-gated image reconstructions that excluded data acquired during bulk motion. Tidal volumes were calculated from end-expiration and end-inspiration images. Respiratory rates were calculated from the Fourier transform of the motion-tracking waveform during quiet breathing, with comparison to physiologic prediction in neonates and validation with spirometry in adults.

RESULTS:

High-quality respiratory-gated anatomic images were obtained at inspiration and expiration, with less respiratory blurring at the expense of signal-to-noise for narrower gating windows. Inspiration-expiration volume differences agreed with physiologic predictions (neonates; Bland-Altman bias = 6.2 mL) and spirometric values (adults; bias = 0.11 L). MRI-measured respiratory rates compared well with the observed rates (biases = -0.5 and 0.2 breaths/min for neonates and adults, respectively).

CONCLUSIONS:

Three-dimensional radial pulmonary UTE MRI allows for retrospective respiratory self-gating and removal of intermittent bulk motion in free-breathing, non-sedated neonates and adults. Magn Reson Med 77:1284-1295, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

KEYWORDS:

3D radial; lung MRI; neonatal; retrospective motion tracking; self-gating; ultrashort echo time

PMID:
26972576
PMCID:
PMC5018908
DOI:
10.1002/mrm.26212
[Indexed for MEDLINE]
Free PMC Article

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