The density ratio of grey to white matter on computed tomography as an early predictor of vegetative state or death after cardiac arrest

• Published in: Emergency medicine journal : EMJ Vol. 25; no. 10; p. 666
• Main Authors: Choi, S P, Park, H K, Park, K N, Kim, Y M, Ahn, K J, Choi, K H, Lee, W J, Jeong, S K
• Format: Journal Article
• Language: English
• Published: England 01-10-2008
• Subjects: Adult; Aged; Aged, 80 and over; Brain - diagnostic imaging; Cardiopulmonary Resuscitation - methods; Case-Control Studies; Female; Glasgow Outcome Scale; Heart Arrest - diagnostic imaging; Humans; Male; Middle Aged; Persistent Vegetative State - diagnostic imaging; Prognosis; Retrospective Studies; Tomography, X-Ray Computed - methods
• ISSN: 1472-0213
• DOI: 10.1136/emj.2007.053306

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.
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.
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%.
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.