Multistage three-dimensional UTE lung imaging by image-based self-gating.
OBJECTIVE
To combine image-based self-gating (img-SG) with ultrashort echo time (UTE) three-dimensional (3D) acquisition for multistage lung imaging during free breathing.


METHODS
Three k-space ordering schemes (modified spiral pattern, quasirandom numbers and multidimensional Golden Angle) providing uniform coverage of k-space were investigated for providing low-resolution sliding-window images for image-based respiratory self-gating. The performance of the proposed techniques were compared with the conventional spiral pattern and standard DC-based self-gated methods in volunteers during free breathing.


RESULTS
Navigator-like respiratory signals were successfully extracted from the sliding-window data by monitoring the lung-liver interface displacement. A temporal resolution of 588 ms was adequate to retrieve gating signals from the lung-liver interface. Images reconstructed with the img-SG technique showed significantly better sharpness and apparent diaphragm excursion than any of the DC-SG methods. Direct comparison of the three implemented ordering schemes did not demonstrate any clear superiority of one with respect to the others.


CONCLUSIONS
Image-based respiratory self gating in UTE 3D lung images allows successful retrospective respiratory gating, also enabling reconstruction of intermediate respiratory stages.
Core Facility Small Animal Imaging, Medical Faculty, Ulm University, Ulm, Germany.
Marta
M
Tibiletti
Department of Internal Medicine II, Ulm University, Ulm, Germany.
Jan
J
Paul
Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research, In-vivo Imaging Laboratory, Biberach an der Riss, Germany.
Andrea
A
Bianchi
Department of Internal Medicine II, Ulm University, Ulm, Germany.
Stefan
S
Wundrak
Department of Internal Medicine II, Ulm University, Ulm, Germany.
Wolfgang
W
Rottbauer
Boehringer Ingelheim Pharma GmbH & Co. KG, Target Discovery Research, In-vivo Imaging Laboratory, Biberach an der Riss, Germany.
Detlef
D
Stiller
Core Facility Small Animal Imaging, Medical Faculty, Ulm University, Ulm, Germany.|Department of Internal Medicine II, Ulm University, Ulm, Germany.
Volker
V
Rasche
D000328:Adult; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012119:Respiration; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012189:Retrospective Studies
3D UTE; image-based self gating; morphological lung imaging; respiratory self-gating; retrospective self-gating