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Measurement of Cerebral Venous
Susceptibility in Healthy Volunteers Before
and After Caffeine Administration Using
Quantitative Susceptibility Techniques
Philip Eaton, Paggie Kim, Christopher Toensing, J. Paul Jacobson
Department of Radiology, Loma Linda University Medical Center
EP-1-2336
Disclosures
»None
Background
» Quantitative Susceptibility Mapping (QSM)
Extension of traditional susceptibility
weighted imaging (SWI)
Each acquired voxel within a given
structure can be quantified in parts per
billion (ppb), which is linearly proportional
to the susceptibility within the voxel.
Wang, Y. and Liu, T. (2015), Quantitative susceptibility mapping (QSM): Decoding MRI data for a tissue magnetic biomarker. Magn Reson Med, 73: 82–101. doi: 10.1002/mrm.25358
Background
»SWI is extremely sensitive to paramagnetic
substances such as Iron
»Deoxyhemoglobin is a paramagnetic substance
Increased deoxyhemoglobin concentration
results in lower signal intensity on SWI and
higher signal on QSM.
Quantitative susceptibility mapping: current status and future directions, Haacke, E. Mark et al., Magnetic Resonance Imaging , Volume 33 , Issue 1 , 1 - 25
Background
»Physiologic, pharmacologic and pathologic
stimuli cause alterations in the amount of
deoxyhemoglobin within cerebral venous
blood.
Quantitative susceptibility mapping: current status and future directions, Haacke, E. Mark et al., Magnetic Resonance Imaging , Volume 33 , Issue 1 , 1 - 25
Background
»Caffeine can alter the amount of
deoxyhemoglobin within cerebral venous
blood.
Caffeine increases oxygen consumption
 increase deoxyhemoglobin concentration
 increase venous signal intensity on QSM
 increases quantitative susceptibility values
Bauer, J., K. Maier, O. Linderkamp, and R. Hentschel. "Effect of Caffeine on Oxygen Consumption and Metabolic Rate in Very Low Birth Weight Infants With Idiopathic Apnea."Pediatrics 107.4 (2001): 660-63. Web.
Background
»Novel Technology
QSM is in it’s infancy. As a result, the range
of normal values and expected magnitude of
response to physiologic, pharmacologic and
pathologic stimuli is not well documented.
Purpose
»To establish reference values for deep and
superficial venous susceptibility, which
reflects deoxyhemoglobin concentration, in
healthy volunteers at baseline and following
caffeine administration
Materials and Methods
»Study design
Subjects
• Twenty-three caffeine naive volunteers
Imaging
• Baseline 3T MRI using QSM protocol
• 200 mg dose of caffeine PO
• Repeat 3T MRI with same protocol
Materials and Methods
»Study design
Analysis
• Susceptibility maps generated with
SMART software package
Materials and Methods
Susceptibility measured using
SPIN/SWIM in five veins:
• Straight sinus
• Bilateral internal cerebral
veins
• Bilateral most prominent
cortical vein in MCA
territory
Materials and Methods
»QSM: An ROI is shown
along the straight sinus in
this subject.
»The maximum
susceptibility was
measured and recorded in
each vein before and after
caffeine administration.
Materials and Methods
»Statistics
The median of differences between pre- and postcaffeine susceptibility was tested using the
Related-samples Wilcoxon signed rank test for
each vein
Results
Before Caffeine
After Caffeine
Representative quantitative susceptibility maps of the same patient before(left) and
after(right) caffeine. Note the increased intensity of the venous structures following
caffeine.
Results
Cerebral Venous Susceptibility Before and After Caffeine
Vessel
Baseline(ppb)
Caffeine(ppb)
Delta(ppb)
p
SS
475.6 ± 136.4
697.1 ± 237.4
221.5
0.000
Right ICV
283.9 ± 61.7
398.8 ± 99.9
114.9
0.000
Left ICV
294.3 ± 63.6
425.7 ± 133.3
131.4
0.000
Right CV
246.9 ± 78.8
361.0 ± 100.7
114.1
0.000
Left CV
218.2 ± 74.4
375.4 ± 147.4
157.3
0.000
SS - Straight sinus; ICV - Internal cerebral vein; CV - Cortical vein
Results
Conclusion
» The average baseline susceptibility is 476 ppb in the SS, 289
ppb in the ICV and 233 ppb in the most prominent CV in our
cohort of normal volunteers.
» The average susceptibility delta of 221 ppb in the SS, 117 ppb
in the ICV and 125 ppb in the CV following caffeine
administration in the same patient population.
» Although limited by small sample size, these findings represent
a preliminary framework which can be referenced when
analyzing quantitative susceptibility weighted imaging.