[Clinical relevance of cranial CT under emergency conditions--basic neuroradiologic investigations]

To determine the diagnostic accuracy of cranial CT under emergency conditions.

Four hundred cranial CT examinations (cerebrum, petrosal bone, fascial bone, sinuses, orbita) were evaluated retrospectively and correlated with the initial neurologic examination, the discharge and surgical diagnoses, and the results of other imaging modalities (conventional X-Ray, MRI, angiography). The average age was 49 (2 to 89) years, with 42 % male and 58 % female patients. The discharge diagnosis was defined as the gold standard, assuming that clinical examinations and laboratory and imaging studies were maximized to establish the diagnosis, together with any possible surgery.

Overall sensitivity, specificity and diagnostic accuracy was 85 %, 70 % and 82 % for cranial CT, 66 %, 45 % and 61 % for the initial neurologic examination, 79 % and 29 % for acute cerebral infarction, and 65% and 13% for intracranial bleeding. Correlation of the CT diagnoses to the discharge and surgical diagnoses was high (82 % and 80 %, respectively; p < 0.01), to the diagnosis of conventional x-ray moderate and to the diagnoses of angiography and MRI unsatisfactory (74 % and 68 % and 60 %, respectively; p > 0.05). Craniotomy was performed in 47 of 400 (12%) patients after cranial CT, within 12 hours in 29, in 12 to 24 hours in 8, and after 24 hours in 10 patients. The risk for intracranial bleeding in patients with a skull fracture was increased by a factor of 3.3.

The high diagnostic accuracy of cranial CT in establishing a precise, timely and reproducible diagnosis confirms the important role of CT as primary diagnostic method under emergency conditions.