Quantitative accuracy of delayed hyperperfusion in MRI of transient ischemia in rats

Abstract

A strong hyperperfusion was reported in transient ischemic tissue between 48 and 72 hours after middle cerebral artery occlusion (MCAO). Cerebral blood flow (CBF) estimated by continuous arterial spin labeling (CASL) with short delay after tagging was sensitive to cerebral blood volume (CBV) change. The delayed hyperperfusion may indicate a CBV increase after MCAO. For confirmation of the delayed hyperperfusion, we investigated a transit-time dependency in CASL at two days after MCAO. We also acquired CBF using the dynamic susceptibility contrast (DSC) at the same day. We have confirmed the CBF in transient ischemic tissue is quite higher (179.1+/-21.6 ml/100g/min) than normal tissue (121.0+/-6.9 ml/100g/min) with CASL using tagging delay of 0.4 sec. CBF estimated by DSC also show delayed hyperperfusion in transient ischemic tissue. These results confirm existence of physiological delayed hyperperfusion in transient ischemic area.

Excitatory amino acid transporter 2 downregulation correlates with thalamic neuronal death following kainic acid‐induced status epilepticus in rat

“…A post delay of 400 ms was used for CASL CBF imaging. CASL CBF was calculated in accordance with previous reports . The kainic acid‐treated rats without status epilepticus were subjected to CBF measurement 90 min after the drug injection.…”

“…CASL CBF was calculated in accordance with previous reports. 21 The kainic acid-treated rats without status epilepticus were subjected to CBF measurement 90 min after the drug injection. The average of CASL CBF in each rat was measured in the areas of interest, including MD and Re.…”

Acute cardiac support with intravenous milrinone promotes recovery from early brain injury in a murine model of severe subarachnoid haemorrhage

“…CASL was acquired with a gradient echo sequence (TR/TE=8/4 ms, FA=20 degrees, FOV=20×20 mm 2 , matrix size=64×64, postlabelling delay=400 ms; number of excitations=8; scan time: 1 minute 25 seconds). CBF was calculated as λ/ T 1b ×(M label −M ref )/(M label +(2α−1)M ref ), where M label is the brain tissue signal acquired by brain surface coil 3 seconds after RF irradiation at a labelling position for the neck coil and M ref is the signal with RF irradiation of the control position . In this model, λ (blood‐brain partition coefficient), T 1b and α (efficiency of labelling) were taken to be 0.9 mL/g, 1.7 seconds and 0.9, respectively.…”

“…where M label is the brain tissue signal acquired by brain surface coil 3 seconds after RF irradiation at a labelling position for the neck coil and M ref is the signal with RF irradiation of the control position. 21 In this model, λ (blood-brain partition coefficient), T 1b and α (efficiency of labelling) were taken to be 0.9 mL/g, 1.7 seconds and 0.9, respectively. Mean CBF estimated by CASL, with tau and after a delay of 3 and 0.4 seconds, was measured.…”

Sub-acute Changes on MRI Measures of Cerebral Blood Flow and Venous Oxygen Saturation in Concussed Australian Rules Footballers

“…Increased SvO 2 may also reflect increased cerebral blood flow (CBF) that exceeds cerebellar energy demands [ 14 ]. Like SvO 2 , CBF can also be estimated non-invasively using MRI [ 15 ] and perturbations in CBF have been observed after mTBI, including SRC [ 16 – 19 ]. However, whether there is a relationship between decreased venous susceptibility (i.e., increased SvO 2 ) and increased CBF has yet to be determined.…”