Imaging minor head injury (MHI) in emergency radiology: MRI highlights additional intracranial findings after measurement of trauma biomarker S 100B in patients with normal CCT.
OBJECTIVE To investigate whether MRI in emergency radiology can detect (a) additional trauma related findings after minor head injury (MHI) or (b) structural, non trauma related intracranial lesions when trauma biomarker S 100B concentration is raised, or clinical symptoms are unexplained, or both. METHODS 41 patients with MHI were included. Concentrations of S 100B in serum were measured and categorized using an established cut off at 0.1 mg l( 1) Intracerebral trauma related as well as non trauma related chronic structural findings (atrophy, microangiopathy and chronic parenchymal defects) were assessed by cranial CT (CCT) and MRI by two independent radiologists (UL and LLG) All CCT and MRI results were compared with biomarker S 100B. RESULTS Compared with CCT, MRI detected 10 additional lesions. 5 patients had abnormal MRI with a total of 15 trauma related lesions and showed elevated S 100B concentrations. Although sensitivity of S 100B was 100% specificity was only 25% Patients with structural brain lesions showed significantly higher S 100B serum levels (0.50 and 0.14 mg l( 1) p 0.01) CONCLUSION Biomarker S 100B has proven its high negative predictive value to rule out intracranial bleeding in patients after MHI even if MRI is used as imaging modality. Regarding the low specificity of S 100B, structural lesions of the brain parenchyma not related to the acute trauma may be associated with increased serum concentrations of protein S 100B. ADVANCES IN KNOWLEDGE Biomarker S 100B has a high negative predictive value to rule out intracranial bleeding after MHI. Biomarker S 100B's low specificity may be associated with non traumatic brain parenchyma lesions. MRI is superior to CCT in detecting subtle findings in neuroimaging after MHI. Biomarker S 100B can potentially reduce the large number of normal CCT studies after MHI.
The British journal of radiology