Dose and pulse sequence considerations for hyperpolarized (129)Xe ventilation MRI.
OBJECTIVE
The aim of this study was to evaluate the effect of hyperpolarized (129)Xe dose on image signal-to-noise ratio (SNR) and ventilation defect conspicuity on both multi-slice gradient echo and isotropic 3D-radially acquired ventilation MRI.


METHODS
Ten non-smoking older subjects (ages 60.8±7.9years) underwent hyperpolarized (HP) (129)Xe ventilation MRI using both GRE and 3D-radial acquisitions, each tested using a 71ml (high) and 24ml (low) dose equivalent (DE) of fully polarized, fully enriched (129)Xe. For all images SNR and ventilation defect percentage (VDP) were calculated.


RESULTS
Normalized SNR (SNRn), obtained by dividing SNR by voxel volume and dose was higher for high-DE GRE acquisitions (SNRn=1.9±0.8ml(-2)) than low-DE GRE scans (SNRn=0.8±0.2ml(-2)). Radially acquired images exhibited a more consistent, albeit lower SNRn (High-DE: SNRn=0.5±0.1ml(-2), low-DE: SNRn=0.5±0.2ml(-2)). VDP was indistinguishable across all scans.


CONCLUSIONS
These results suggest that images acquired using the high-DE GRE sequence provided the highest SNRn, which was in agreement with previous reports in the literature. 3D-radial images had lower SNRn, but have advantages for visual display, monitoring magnetization dynamics, and visualizing physiological gradients. By evaluating normalized SNR in the context of dose-equivalent formalism, it should be possible to predict (129)Xe dose requirements and quantify the benefits of more efficient transmit/receive coils, field strengths, and pulse sequences.
Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
Mu
M
He
Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA; Medical Physics Graduate Program, Duke University, Durham, NC, USA.
Scott H
SH
Robertson
Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA.
S Sivaram
SS
Kaushik
Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA; Medical Physics Graduate Program, Duke University, Durham, NC, USA.
Matthew S
MS
Freeman
Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA.
Rohan S
RS
Virgincar
Department of Medicine Pulmonary, Duke University Medical Center, Durham, NC, USA.
John
J
Davies
Department of Medicine Pulmonary, Duke University Medical Center, Durham, NC, USA.
Jane
J
Stiles
Department of Medicine Pulmonary, Duke University Medical Center, Durham, NC, USA.
William M
WM
Foster
Medical Physics Graduate Program, Duke University, Durham, NC, USA; Department of Medicine Pulmonary, Duke University Medical Center, Durham, NC, USA.
H Page
HP
McAdams
Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Radiology, Duke University Medical Center, Durham, NC, USA; Medical Physics Graduate Program, Duke University, Durham, NC, USA. Electronic address: bastiaan.driehuys@duke.edu.
Bastiaan
B
Driehuys
D000280:Administration, Inhalation; D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D012120:Respiration Disorders / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D014463:Ultrasonography; D014979:Xenon Isotopes / Q000008:administration & dosage*
D003287:Contrast Media; D014979:Xenon Isotopes
Hyperpolarized (129)Xe MRI; Pulse sequence; Signal-to-noise ratio; Ventilation defect