Application of Gd-DTPA in diseases of the central nervous system.

Patients whose routine MRI were negative but were clinically highly suspected of having intra-cranial or intra-spinal canal space-occupying lesions, and those whose routine MRI were positive but presented difficulties in defining the contour or the nature of the lesion, or difficulty in distinguishing the lesion from the surrounding edema were selected for Gd-DTPA enhancement. Altogether there were 80 cases, in which 51 had intracranial lesions and 29 intraspinal canal lesions. In each patient, Gd-DTPA 0.06-0.1 mmol/kg was injected intravenously 5 minutes before imaging (pituitary microadenoma images were taken immediately and 10 minutes after injection). No patient had contrast media reaction or complications. In cases with hemorrhage, hematoma, edema, cyst and arteriovenous malformation, no marked enhancement was observed after contrast media injection. When difficulty in differential diagnosis between these lesions and tumors occurs, injection of Gd-DTPA is very helpful. Gd-DTPA enhancement is of great benefit in diagnosis of intracranial or intraspinal canal tumors in four ways. 1) It reveals lesions which can not be demonstrated or can not be demonstrated clearly before enhancement, including iso-intensity lesions and small lesions which comprised 13.7% of our cases. 11 cases with equivocal diagnoses before enhancement obtained unequivocal diagnoses after enhancement. 2) It differentiates the tumor from edema more definitely. 3) It helps to distinguish the nature of lesions. 4) It shortens examination time when the T2 weighted image procedure is omitted.