Ultrasound guided double injection of blood into cisterna magna: a rabbit model for treatment of cerebral vasospasm

Abstract

Background: Double injection of blood into cisterna magna using a rabbit model results in cerebral vasospasm. An unacceptably high mortality rate tends to limit the application of model. Ultrasound guided puncture can provide real-time imaging guidance for operation. The aim of this paper is to establish a safe and effective rabbit model of cerebral vasospasm after subarachnoid hemorrhage with the assistance of ultrasound medical imaging.

Methods: A total of 160 New Zealand white rabbits were randomly divided into four groups of 40 each: (1) manual control group, (2) manual model group, (3) ultrasound guided control group, and (4) ultrasound guided model group. The subarachnoid hemorrhage was intentionally caused by double injection of blood into their cisterna magna. Then, basilar artery diameters were measured using magnetic resonance angiography before modeling and 5 days after modeling.

Results: The depth of needle entering into cisterna magna was determined during the process of ultrasound guided puncture. The mortality rates in manual control group and model group were 15 and 23 %, respectively. No rabbits were sacrificed in those two ultrasound guided groups. We found that the mortality rate in ultrasound guided groups decreased significantly compared to manual groups. Compared with diameters before modeling, the basilar artery diameters after modeling were significantly lower in manual and ultrasound guided model groups. The vasospasm aggravated and the proportion of severe vasospasms was greater in ultrasound guided model group than that of manual group. In manual model group, no vasospasm was found in 8 % of rabbits.

Conclusions: The ultrasound guided double injection of blood into cisterna magna is a safe and effective rabbit model for treatment of cerebral vasospasm.

Fig. 1

Cisterna magna and atlano-occipital fascia in CT sagittal image. C cerebellum, EOP external occipital protuberance, AOF atlano-occipital fascia, CM cisterna magna, BS brain stem

Fig. 2

Measurement and observation of cisterna magna that is guided by ultrasound. a Cisterna magna and adjacent structures were displayed by ultrasound. b Depth of cisterna magna was measured at its optimal part. The puncture direction was designed based on the line from atlano-occipital fascia to the deepest part of cisterna magna. CM cisterna magna, BS brain stem, EOP external occipital protuberance

Fig. 3

Illustration of puncture direction in MR sagittal image. C cerebellum, CM cisterna magna, BS brain stem, Arrow 1 puncture direction in manual model group (vertical line), Arrow 2 puncture direction in ultrasound guided model group

Fig. 4

Ultrasound guided puncture procedure. a Needle was showed in the puncture procedure. b When blood was injected, the signal of flow blood was monitored by ultrasound, and boundary between cisterna magna and brain stem was disturbed by the high signal. c Blood in subarachnoid space at 1 day after modeling. CM cisterna magna, BS brain stem, Blue line dura mater, Red arrowhead puncture needle, Blue block blood signal, Red arrow blood in subarachnoid space

Fig. 5

Comparison of mortality rates among four groups

Fig. 6

Comparison of basilar artery diameter among four groups. **Compare with the diameter before modeling, P < 0.05. ^##Compare with the diameter in the manual group, P < 0.05. ^††Compare with the diameter in the control group, P < 0.05

Fig. 7

Observation of basilar artery in MRA before and after modeling. a, b Manual control group. c, d Ultrasound guided control group. e, f Manual model group. g, h ultrasound guided model group. a, c, e, g Before modeling. b, d, f, h 5 days after modeling. BA basilar artery, VA vertebral artery