Abstract #0214
Are blood flow measurements by means of Transcranial Doppler valid under different levels of end-tidal CO2? A high resolution MRI study at 7 Tesla of the middle cerebral artery diameter under hypo- and hypercapnic conditions
Jasper Verbree 1,2 , Eidrees Ghariq 1,2 , Anne-Sophie Bronzwaer 3,4 , Maarten Versluis 1,2 , Mat Daemen 5 , Mark van Buchem 1 , Albert Dahan 6 , Johannes van Lieshout 3,4 , and Matthias van Osch 1,2
1
Radiology, Leiden University Medical Center,
Leiden, Netherlands,
2
C.J.
Gorter Center for High-Field MRI, Leiden University
Medical Center, Leiden, Netherlands,
3
Laboratory
for Clinical Cardiovascular Physiology, Academic Medical
Center, Amsterdam, Netherlands,
4
Internal
Medicine, Academic Medical Center, Amsterdam,
Netherlands,
5
Pathology,
Academic Medical Center, Amsterdam, Netherlands,
6
Anesthesiology,
Leiden University Medical Center, Leiden, Netherlands
Changes in blood flow velocity measured with
Transcranial Dopper (TCD) are frequently interpreted as
being proportional to cerebral blood flow assuming a
constant diameter of the insonated vessel. Reported data
on vessel diameter changes under influence of CO2 are
inconsistent. High resolution MR imaging was used to
measure the diameter of the middle cerebral artery (MCA)
in healthy volunteers. Four levels of end-tidal CO2 were
administered via a face mask. Results indicate that
moderate hypercapnia (+2 kPa above resting
concentration) increases MCA diameter 17%. A quadratic
model is proposed to correct for diameter changes under
different end-tidal CO2 conditions.
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