Special Imaging Technique to Aid in the Diagnosis of Patients in Coma After Cardiac Arrest

Inclusion Criteria: * All adult patients (age range: 18-80 years), in a coma for at least 24 hours following cardiac arrest who are admitted to our cardiac intensive care unit and who have recovered body temperature back to normal after being subjected to the therapeutic hypothermia protocol will be included in the study. * Also included are those patients whose next of kin have provided consent for the study. Exclusion Criteria: * patients who are pregnant, * those with impaired renal function, * those who have contraindications to the CT contrast media (such as a known allergy or anaphylactic reactions) and * those who do not provide consent. Pregnant patients will be excluded to avoid any potential adverse effect of radiation from CT perfusion study on the developing foetus. A developing foetus is more vulnerable to radiation when compared to adult patients. Patients above 80 years will be excluded to avoid age related comorbidities affecting the patients' survival. We do not see patients below 18 years of age at our institution thus they will be excluded.