Alterations in intracranial volume following cross-clamping of the descending thoracic aorta in pigs--an experimental study using MRI.
OBJECTIVE
To determine whether alterations in intracranial volume occurred following cross-clamping of the descending thoracic aorta in pigs.


METHODS
Laboratory animal study.


METHODS
Eight pigs undergoing cross-clamping of the descending thoracic aorta for 30 min.


METHODS
A Philips Gyroscan T5-II Release 3 (0.5 T) was used to obtain intracranial images before cross-clamping, during cross-clamping and after declamping. The ventricular volume was measured on Spin Echo T1-weighted images. The signal intensity of the cerebral tissue was measured on Spin Echo T2-weighted images. Increased signal intensity of the cerebral tissue relative to an external reference was used as an indicator of cerebral oedema.


RESULTS
The ventricular volume decreased to 89% (p < 0.01) of the baseline value after 5 min of cross-clamping. At 5 min after declamping the ventricular volume decreased further to 71% (p < 0.01). At 25 min after declamping the ventricular volume had returned to the baseline value. The signal intensity of the cerebral tissue did not differ from baseline values following aortic cross-clamping.


CONCLUSIONS
In this study, ventricular volume decreased following cross-clamping of the descending thoracic aorta. Since no cerebral oedema was observed, the decrease of ventricular volume was most likely due to increased intracranial blood volume.
Strømholm
T
T
Department of Surgery, University Hospital of Trondheim, Norway.
Saether
O D
OD
Aadahl
P
P
Nilsen
G
G
Kvaerness
J
J
Myhre
H O
HO
D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology*; D001929:Brain Edema / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D002555:Cerebrospinal Fluid / Q000502:physiology*; D015170:Cerebrospinal Fluid Pressure; D003250:Constriction; D006439:Hemodynamics; D008279:Magnetic Resonance Imaging; D013552:Swine