Functional imaging of the parotid glands using blood oxygenation level dependent (BOLD)-MRI at 1.5T and 3T.
OBJECTIVE
To evaluate the function of the parotid glands before and during gustatory stimulation, using an intrinsic susceptibility-weighted MRI method (blood oxygenation level dependent, BOLD-MRI) at 1.5T and 3T.


METHODS
A total of 10 and 13 volunteers were investigated at 1.5T and 3T, respectively. Measurements were performed before and during gustatory stimulation using ascorbate. Circular regions of interest (ROIs) were delineated in the left and right parotid glands, and in the masseter muscle for comparison. The effects of stimulation were evaluated by calculating the difference between the relaxation rates, DeltaR(2)*. Baseline and stimulation were statistically compared (Student's t-tests), merging both parotid glands.


RESULTS
The averaged DeltaR(2)* values prestimulation obtained in all parotid glands were stable (-0.61 to 0.38 x 10(-3) seconds(-1)). At 3T, these values were characterized by an initial drop (to -2.7 x 10(-3) seconds(-1)) followed by a progressive increase toward the baseline. No significant difference was observed between baseline and parotid gland stimulation at 1.5T, neither for the masseter muscle at both field strengths. A considerable interindividual variability (over 76%) was noticed at both magnetic fields.


CONCLUSIONS
BOLD-MRI at 3T was able to detect DeltaR(2)* changes in the parotid glands during gustatory stimulation, consistent with an increase in oxygen consumption during saliva production.
Institute of Diagnostic, Interventional and Pediatric Radiology, University and Inselspital, Bern, Switzerland.
Sonia C
SC
Simon-Zoula
Chris
C
Boesch
Frederik
F
De Keyzer
Harriet C
HC
Thoeny
D000328:Adult; D019540:Area Under Curve; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008406:Masseter Muscle / Q000502:physiology; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010306:Parotid Gland / Q000502:physiology*; D012463:Saliva / Q000378:metabolism