Value of Three-Dimensional Maximum Intensity Projection Display to Assist in Magnetic Resonance Imaging (MRI)-Based Grading in a Mouse Model of Subarachnoid Hemorrhage

Abstract

BackgroundSubarachnoid hemorrhage (SAH) is one of the most devastating cerebrovascular disorders. We report on the diagnostic value of three-dimensional (3-D) maximum intensity projection (MIP) reconstruction of T2*-weighted magnetic resonance images (MRI), processed using graphical user interface-based software, to aid in the accurate grading of endovascular-perforation-induced SAH in a mouse model.Material/MethodsA total of 30 mice were subjected to SAH by endovascular perforation; three (10%) were scored as grade 0, six (20%) as grade 1, six (20%) as grade 2, eight (27%) as grade 3, and seven (23%) as grade 4 according to T2*-weighted coronal slices. In comparison, none of mice were scored as grade 0, eight (27%) as grade 1, five (17%) as grade 2, nine (30%) as grade 3, and eight (27%) as grade 4 based on subsequent evaluation using reconstructed 3-D MIP images.ResultsMice scored as grade 0 (10%; no visible SAH) on T2*-coronal images were categorized as grades 1 (thin/localized SAH) and 3 (thick/diffuse SAH) according to 3-D MIP images. Grades based on T2* 3-D MIP images were more closely correlated with conventional SAH score (r2=0.59; P<0.0001) and neurological score (r2=0.25; P=0.005) than those based on T2*-coronal slices (r2=0.46; P<0.0001 for conventional score and r2=0.15; P=0.035 for neurological score).ConclusionsThese results suggest that 3-D MIP images generated from T2*-weighted MRI data may be useful for the simple and precise grading of SAH severity in mice to overcome the weakness of the current MRI-based SAH grading system.

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

“…Following failure of the righting reflex, mice were placed on a warmed platform in the supine position and the femoral artery was catheterized along with the tail vein for blood gas analysis and drug administration, respectively. SAH was induced by endovascular perforation using a 5‐0 monofilament suture at the terminal of the left internal carotid artery as described . In sham‐operated mice, the suture was introduced into the internal carotid artery, but without vessel perforation.…”

“…Whole‐brain MRI was performed to ensure correct head positioning with acquisition of diffusion‐weighted images (DWI) with fast spin echo sequences (TR/TE=2000/80 ms, FOV=20×20 mm 2 , matrix size=128 RO×64 PE zero filled to 128×128 [b‐value 1008.7; large delta 40 ms; small delta 10 ms]; slice interval 1.0 mm, thickness 0.8 mm [slice gap 0.2 mm]; scan time: 2 minutes 18 seconds), T2‐weighted images (T2WI) with fast spin echo sequences (TR/TE=2000/80 ms, FOV=20×20 mm 2 , matrix size=128×128; slice interval 1.0 mm, thickness 0.8 mm [slice gap 0.2 mm]; scan time: 4 minutes 21 seconds) and 3‐dimentional T2*WI with gradient echo sequences (long TR/TE=20/10 ms, FA=20 degrees, FOV=20×20×20 mm 3 , matrix size=128×128×128; scan time: 5 minutes 29 seconds) . Continuous arterial spin labelling (CASL) was performed using a two‐coil system with a labelling neck coil and quadrature brain surface coil (Rapid Biomedical, Rimpar, Germany).…”

Preceding functional tooth loss delays recovery from acute cerebral hypoxia and locomotor hypoactivity after murine subarachnoid haemorrhage

“…After one-week of stabilization period, mice were subjected to SAH under isoflurane anaesthesia by endovascular perforation using a 5-0 monofilament suture at the terminal of the left internal carotid artery as described. 30 After SAH induction and postoperative magnetic resonance image (MRI) data acquisition (see below), mice were allowed to recover from anaesthesia and rested in a warmed cage for recovery. A 1.2 mL of half-strength dextrose/ saline solution was administered subcutaneously twice daily for 3 consecutive days to prevent dehydration.…”

“…Grading of SAH was determined by T2*WI on day 1 after the induction. 30 Newly developed cerebral infarction was defined by hyperintense signals on serial MRI examinations (DWI and T2WI) on days 1 and 3 ( Figure 1A). Neurobehavioural function was assessed on 3, 7, and 14 days after SAH.…”

Rapamycin protects against early brain injury independent of cerebral blood flow changes in a mouse model of subarachnoid haemorrhage

“…In this study, 20 mice (n = 10 per group) underwent successful development of diffuse SAH corresponding to severe clinical grades, in which 12 animals were scored as grade 3 (thick SAH without intraventricular haemorrhage) and 8 were defined as grade 4 (thick SAH with intraventricular haemorrhage) according to the T2*WI-based MRI grading scale (P = .66; Fisher's exact test). 10,13 In both groups, global depression of signals showing cerebral blood flow of bilateral middle cerebral arteries and brain tissue oxygen saturation (SbtO 2 ) was notable immediately after SAH induction (P < .001; within-subject factors by 2-way ANOVA), which recovered to close to baseline level within 48 hours ( Figure 1A). Although the time course changes in peak cerebral blood flow velocity (PFV) values did not differ significantly between groups (P = .58; betweensubject factors by 2-way ANOVA; Figure 1B), rapamycin-pretreated mice showed milder cerebral hypoxia compared with controls (P < .001; Bonferroni-Dunn post hoc test), and a shorter mean duration of hypoxia (11 ± 9 vs 26 ± 9 hour, P = .002; Mann-Whitney U test; Figure 1C).…”