Bolus tracking for improved metabolic imaging of hyperpolarised compounds.
Dynamic nuclear polarisation has enabled real-time metabolic imaging of pyruvate and its metabolites. Conventional imaging sequences rely on predefined settings and do not account for intersubject variations in biological parameters such as perfusion. We present a fully automatic real-time bolus tracking sequence for hyperpolarised substrates which starts the imaging acquisition at a defined point on the bolus curve. This reduces artefacts due to signal change and allows for a more efficient use of hyperpolarised magnetisation. For single time point imaging methods, bolus tracking enables a more reliable and consistent quantification of metabolic activity. An RF excitation with a small flip angle is used to obtain slice-selective pyruvate tracking information in rats. Moreover, in combination with a copolarised urea and pyruvate injection, spectrally selective tracking on urea allows obtaining localised bolus tracking information without depleting the pyruvate signal. Particularly with regard to clinical application, the bolus tracking technique could provide an important step towards a routine assessment protocol which removes operator dependencies and ensures comparable results.
Department of Medical Engineering, Technische Universität München, Boltzmannstrasse 11, 85748 Garching, Germany; GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany. Electronic address: markus.durst@tum.de.
Markus
M
Durst
Department of Medical Engineering, Technische Universität München, Boltzmannstrasse 11, 85748 Garching, Germany; GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany.
Ulrich
U
Koellisch
Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Straße 22, 81675 Munich, Germany.
Concetta
C
Gringeri
GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany.
Martin A
MA
Janich
GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany; Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Straße 22, 81675 Munich, Germany.
Giaime
G
Rancan
Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Ismaninger Straße 22, 81675 Munich, Germany.
Annette
A
Frank
GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany.
Florian
F
Wiesinger
GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany.
Marion I
MI
Menzel
Department of Medical Engineering, Technische Universität München, Boltzmannstrasse 11, 85748 Garching, Germany.
Axel
A
Haase
GE Global Research, Freisinger Landstrasse 50, 85748 Garching, Germany.
Rolf F
RF
Schulte
D000818:Animals; D002247:Carbon Isotopes / Q000737:chemistry / Q000493:pharmacokinetics; D003198:Computer Simulation; D007553:Isotope Labeling; D007668:Kidney / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D019289:Pyruvic Acid / Q000737:chemistry / Q000493:pharmacokinetics*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D002247:Carbon Isotopes; D019289:Pyruvic Acid
Bolus tracking; Hyperpolarisation; Magnetic resonance spectroscopy; Metabolic imaging; Spectral–spatial excitation; [1-13C]pyruvate; [13C]urea