The Lancet - Saturday II October 1975. Sodium iothalamate as an aid to diagnosis of intracranial lesions by computerised transverse axial scanning.

The diagnostic accuracy of computerised transverse axial tomography in conjunction with enhancement of tissue density by sodium iothalamate was assessed in 438 patients, 256 of them having intracranial tumours and 182 having other intracranial disorders. THE 80 X 80 matrix and 20 ml intravenous sodium iothalamate were used in 174 patients, the 160 X 160 matrix and 20 ml sodium iothalamate in 126 patients, and the 160 X 160 matrix and 60 ml sodium iothalamate in 138 patients. The diagnostic accuracy rose from 87% in the first group to 100% in the final group. The proportion of patients showing enhancement of tumour tissue density improved from 64% in the first group to 96% in the third. In the non-tumour patients, excluding those in whom the underlying disease caused no alteration of brain structure or tissue density, the overall accuracy was 96%, being unaffected by the modifications of technique. The enhancement of tissue density in brain abscesses, some cerebral infarcts, and angiomas could be readily distinguished from that seen in tumours.