Increased accuracy in MR diagnosis of uveal melanoma by carbohydrate loading. A simple method that reflects rapid metabolic change.

OBJECTIVE

To evaluate patients with clinically diagnosed uveal melanoma.

METHODS

Forty-eight consecutive patients were examined with spin-echo (SE) and fast spin-echo (FSE) MR sequences that utilized glucose-fructose enhancement together with a subtraction technique on a 1.5 T unit.

RESULTS

Twenty-seven patients were enucleated and the eyes histologically examined for tumours (spindle cell, mixed cell, and epitheloid cell). The remaining patients were referred for other treatment. There were no significant differences in T2 although T2 was longer in the amelanotic lesions. Carbohydrate loading in combination with a subtraction technique gave: an increased signal intensity; a prolongation of T2; and an increased tumour size. The FSE sequences were as good as the SE sequences in the visualization of uveal malignant melanoma.

CONCLUSIONS

MR imaging performed with carbohydrate loading registers metabolic changes induced in the tumour. This gives the method great validity in the diagnosis of uveal melanoma. The method is especially useful in amelanotic tumours that have longer relaxation times than melanotic tumours. The SE technique can be replaced with the FSE technique.