Cerebrovascular reactivity by quantitative magnetic resonance angiography with a Co₂ challenge. Validation as a new imaging biomarker.
Assessment of cerebrovascular reactivity (CVR) is essential in cerebrovascular diseases, as exhausted CVR may enhance the risk of cerebral ischemic events. Transcranial Doppler (TCD) with a vasodilatory stimulus is currently used for CVR evaluation. Scanty data are available for Quantitative Magnetic Resonance Angiography (QMRA), which supplies higher spatial resolution and quantitative cerebral blood flow values. Aims of our pilot study were: (a) to assess safety and feasibility of CO2 administration during QMRA, (b) evaluation of CVR under QMRA compared to TCD, and (c) quantitative evaluation of blood flow from the major intracranial arterial vessels both at rest and after CO2. CVR during 5% CO2 air breathing was measured with TCD as a reference method and compared with QMRA. Fifteen healthy subjects (age 60.47 ± 2.24; male 11/15) were evaluated at rest and during CO2 challenge. Feasibility and safety of QMRA under CO2 were ensured in all subjects. CVR from middle cerebral artery territory was not statistically different between TCD and MRI (p>0.05). Mean arterial pressure (MAP) and heart rate (HR) increased during QMRA and TCD (MAP p=0.007 and p=0.001; HR p=0.043 and p=0.068, respectively). Blood flow values from all intracranial vessels increased after CO2 inhalation (p<0.001). CO2 administration during QMRA sessions is safe and feasible. Good correlation in terms of CVR was obtained comparing TCD and QMRA. Blood flow values significantly increased from all intracranial arterial vessels after CO2. Studies regarding CVR in physiopathological conditions might consider the utilization of QMRA both in routine clinical settings and in research projects.
Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: lcaputi@istituto-besta.it.
Luigi
L
Caputi
Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: Francesco.Ghielmetti@istituto-besta.it.
Francesco
F
Ghielmetti
Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: Giuseppe.Farago@istituto-besta.it.
Giuseppe
G
Faragò
Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: fabio.longaretti@libero.it.
Fabio
F
Longaretti
Department of Neuroanesthesia and Intensive Care, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: docmassimomd@gmail.com.
Massimo
M
Lamperti
Service of Neurology, S. Orsola Hospital, Fondazione Poliambulanza, Via Vittorio Emanuele II 27, 25122 Brescia, Italy. Electronic address: gpanzola@speedyposta.it.
Gian Paolo
GP
Anzola
Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: MariaRita.Carriero@istituto-besta.it.
Maria Rita
MR
Carriero
Department of Neurosurgery, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA. Electronic address: fcharbel@uic.edu.
Fady T
FT
Charbel
Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: Maria.Bruzzone@istituto-besta.it.
Maria Grazia
MG
Bruzzone
Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: Eugenio.Parati@istituto-besta.it.
Eugenio
E
Parati
Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy. Electronic address: Elisa.Ciceri@istituto-besta.it.
Elisa
E
Ciceri
D000280:Administration, Inhalation; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002245:Carbon Dioxide / Q000008:administration & dosage*; D002560:Cerebrovascular Circulation / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D010865:Pilot Projects; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
D002245:Carbon Dioxide
Cerebrovascular reactivity; Magnetic Resonance Imaging (MRI).; Quantitative Magnetic Resonance Angiography (QMRA); Transcranial Doppler