Online correction of respiratory-induced field disturbances for continuous MR-thermometry in the breast.
MR-thermometry allows monitoring of the local temperature evolution during minimally invasive interventional therapies. However, for the particular case of MR-thermometry in the human breast, magnetic field variations induced by the respiratory cycle lead to phase fluctuations requiring a suitable correction strategy to prevent thermometry errors. For this purpose a look-up-table-based multibaseline approach as well as a model-based correction algorithm were applied to MR-thermometry to correct for the periodic magnetic field changes. The proposed correction method is compatible with a variety of sensors monitoring the current respiratory state. The ability to remove phase artefacts during MR-thermometry of the human breast was demonstrated experimentally in five healthy volunteers during 3 min of free-breathing using pencil-beam navigators for respiratory control. An increase of 170-530% in temperature precision was observed for the look-up-table-based approach, whereas a further improvement by 16-36% could be achieved by applying the extended model-based correction.
Laboratory for Molecular and Functional Imaging: From Physiology to Therapy, Equipe de Recherche Technologique Centre National de la Recherche Scientifique/Universite Bordeaux 2, Bordeaux, France.
S
S
Hey
G
G
Maclair
B D
BD
de Senneville
M
M
Lepetit-Coiffe
Y
Y
Berber
M O
MO
Köhler
B
B
Quesson
C T W
CT
Moonen
M
M
Ries
D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001831:Body Temperature / Q000502:physiology*; D001940:Breast / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009862:Online Systems; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D013817:Thermography / Q000379:methods*; D055815:Young Adult