Perioperative Changes in Cerebral Perfusion Territories Assessed by Arterial Spin Labeling Magnetic Resonance Imaging Are Associated with Postoperative Increases in Cerebral Blood Flow in Patients with Carotid Stenosis.
OBJECTIVE
The magnetic resonance imaging technique known as territorial arterial spin labeling (TASL) allows for noninvasive visualization of perfusion territories. The objective of this study was to use TASL to assess the relationship between perioperative changes in the perfusion territories of the internal carotid artery (ICA) and cerebral blood flow (CBF) after carotid revascularization.


METHODS
In 32 patients, ICA perfusion volume (PV) and CBF were measured before and after carotid endarterectomy/carotid artery stenting using TASL and single-photon emission computed tomography, respectively. ICA flow was measured during carotid endarterectomy before and after reconstruction, using an electromagnetic flowmeter. Eleven healthy volunteers, as the normal control group, underwent TASL evaluation.


RESULTS
We classified patients into 2 groups: the normal PV group (ICA PV ≥ mean-2 standard deviation of healthy volunteers; n = 13) and the reduced PV group (ICA PV < mean-2 standard deviation; n = 19). The postoperative increase in the ICA PV and CBF were significantly greater in the reduced PV group than in the normal group (90.4% ± 131.8% vs. 10.5 ± 9.8%, P = 0.017, 32.0 ± 25.7% vs. 10.5% ± 10.7%, P = 0.0032, respectively). ICA flow increased significantly after reconstruction in both the normal PV group (115.1 ± 48.1 mL/minute to 159.1 ± 53 mL/minute; P = 0.016) and reduced PV group (57.8 ± 38.3 mL/minute to 182.3 ± 52.6 mL/minute; P < 0.0001). However, in some patients in the reduced PV group, the PV increased only slightly, whereas the ICA flow markedly increased, which resulted in a large CBF increase, such as hyperperfusion.


CONCLUSIONS
The TASL study suggested that an imbalance between increases in the PV and ICA flow could play an important role in the pathophysiology underlying postoperative abnormal increases in CBF.
Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Daisuke
D
Yamamoto
Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan. Electronic address: khosoda@med.kobe-u.ac.jp.
Kohkichi
K
Hosoda
Department of Neurosurgery, Nishiwaki Municipal Hospital, Nishiwaki, Japan.
Yoshito
Y
Uchihashi
Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Atsushi
A
Fujita
Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Takashi
T
Sasayama
Department of Radiology, Kobe Minimally Invasive Cancer Center, Kobe, Japan.
Masahiko
M
Fujii
Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan.
Kazuro
K
Sugimura
Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Masaaki
M
Kohta
Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Eiji
E
Kohmura
D000368:Aged; D000369:Aged, 80 and over; D020520:Brain Infarction / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D002343:Carotid Artery, Internal / Q000502:physiology; D016893:Carotid Stenosis / Q000503:physiopathology* / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon
Arterial spin labeling; Carotid artery stenting; Carotid endarterectomy; Carotid stenosis; Cerebral perfusion; Hyperperfusion; Magnetic resonance imaging