Non-breath-hold lung magnetic resonance imaging with real-time navigation |
| |
Authors: | M A Schmidt G Z Yang J Keegan P Jhooti P D Gatehouse D H Carr D M Hansell D N Firmin |
| |
Affiliation: | (1) Royal Brompton Hospital, Magnetic Resomance Unit, London, UK;(2) Magnetic Resonance Unit, St. George's Hospital, SW17 0QT London, Blackshaw Road, UK |
| |
Abstract: | Magnetic resonance imaging (MRI) with navigating techniques based on consecutive breath-holds demand a level of respiratory
control that is often beyond the capability of patients with lung disease. The objectives of this investigation were to develop
and evaluate a navigating technique for lung MRI that does not rely on patient cooperation. Navigating techniques were implemented
at 0.5 T using conventional imaging techniques of short echo-time and imaging during normal breathing in the diastolic phase
of the cardiac cycle. A column of spins, orthogonal to the diaphragm, was excited both immediately before and after the imaging
segment. These signals were processed in real time to provide the position of the lung-diaphragm interface. An imaging segment
was considered correctly acquired only when the interface position was within the acceptance window both before and after
the acquisition of the segment. A distribution of lung-diaphragm interface positions obtained during normal respiration was
employed to define the acceptance window. In the case of multislice techniques, the position of the lung-diaphragm interface
immediately before the imaging segment was also employed to decide which phase-encoding step to acquire next, therefore reducting
the apparent frequency of the respiratory motion. A distribution of interface position, updated in real time, served as a
reference for the allocation of phase-encoding steps according to diaphragm position. The lung images obtained represent a
significant advance in image quality, improving further the ability of MR to detect and monitor pulmonary disease. Motion
artifacts were reduced, and images reliably demonstrated smaller vessels, which are not normally visible without navigation. |
| |
Keywords: | MRI lung real-time navigation motion artifacts |
本文献已被 SpringerLink 等数据库收录! |
|