Objectives: Cranial CT scans are amongst the most frequently performed radiological investigations performed in most developed countries. However, these tests are relatively expensive and economic realities should compel physicians to re-evaluate the utilization of this technology. The aim of this study was to review the utilization pattern and effect on management decisions of cranial CT scanning.
Design: Retrospective chart review.
Setting: University-affiliated community teaching hospital.
Subjects: The clinical data on 451 consecutive patients undergoing cranial CT scanning in our radiology department were reviewed. Eighty-five patients were referred from outside the hospital and were subsequently excluded from further analysis.
Main outcome measures: The following data was abstracted from each patient's chart: the presenting clinical syndrome, the physician ordering the scan, details of the neurological examination performed prior to scanning, the CT scan findings and the impact the CT scan findings had on management decisions.
Results: The largest percentage of patients were referred from the emergency department (61%). Chronic intracranial lesions were present in 77 (21%) patients. New pathological findings were found in 91 (25%) patients. The commonest new lesions were ischaemic infarcts (43%), followed by intracerebral haemorrhage (13%) and space occupying lesions (11%). Ninety-seven per cent of patients presenting with new focal neurological signs had new findings on the CT scan, compared to 28% of patients with severe headache and 27% with a history of loss of consciousness. Head trauma was the presenting problem in 139 patients. New pathological findings were diagnosed in 24 of these patients. Fifty-four patients had no signs or symptoms referable to the central nervous system. None of these patients had new findings on CT scan. In the vast majority of patients the neurological examination performed prior to CT scanning was incomplete. CT scanning was considered to have altered the management or provided a new diagnosis in 162 (44%) patients; of these patients 61 (67%) were in the group with new findings on CT scanning and 101 (37%) in the group with no new findings.
Conclusion: In this study cranial CT scanning affected clinical management decisions in less than half of the patients. Furthermore, a careful history and neurological examination was performed in the minority of patients undergoing CT scanning. It would therefore appear that the easy accessability of CT scans largely determines the utilization of this diagnostic tool.