The density ratio of grey to white matter on computed tomography as an early predictor of vegetative state or death after cardiac arrest.
OBJECTIVE
To evaluate whether the ratio (in Hounsfield units; HU) of grey matter (GM) to white matter (WM) on computed tomography (CT) scans taken within 24 h of resuscitation can be used as a predictor of outcome.


METHODS
28 patients who resuscitated from cardiac arrest and had head CT performed within 24 h of resuscitation were retrospectively investigated. 27 subjects with normal head CT findings served as controls. Comatose patients were divided into two groups: those with a Glasgow outcome scale (GOS) score of 3-5 (good outcome subgroup) and those with a GOS score of 1-2 (poor outcome subgroup). HU were measured in GM and WM at the level of the basal ganglia on non-contrast CT scans.


RESULTS
The density ratio of GM to WM was significantly lower in comatose patients than in controls (mean 1.21 vs 1.32, p<0.001). The GM:WM ratio was significantly lower in the poor subgroup than in the good subgroup (mean 1.19 vs 1.28, p<0.001). Receiver operating characteristic curve analysis determined a cutoff value of a GM:WM ratio of less than 1.22 for vegetative state or death. This value predicted vegetative state or death with a sensitivity of 63%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 56%.


CONCLUSIONS
The GM/WM ratio correlates with the outcome of hypoxic ischaemic encephalopathy and may be useful as an objective early predictor of vegetative state or death in comatose patients after cardiac arrest.
Choi
S P
SP
Department of Emergency Medicine, St Mary's Hospital, 62 Yeouido-dong, Yeongdeungpo-gu, Seoul, Korea.
Park
H K
HK
Park
K N
KN
Kim
Y M
YM
Ahn
K J
KJ
Choi
K H
KH
Lee
W J
WJ
Jeong
S K
SK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging*; D016887:Cardiopulmonary Resuscitation / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D023261:Glasgow Outcome Scale; D006323:Heart Arrest / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018458:Persistent Vegetative State / Q000000981:diagnostic imaging*; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*