Acoustic tumors

Magnetic resonance imaging (MRI) was performed in 21 patients with clinical and histologic diagnoses of acoustic tumor with 0.15 Tesla and 0.5 Tesla whole body image scanner (Hitachi G-10, G-50). Eleven patients were evaluated by MRI before and after an intravenous injection of 0.1 mmol/kg of gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA). Contrast enhancement was seen in all cases. The degree of enhancement was greater with T-1 weighed images such as saturation-recovery (500/20 - 30) and inversion-recovery (2000/500/20) than with T-2 weighed images such as spin-echo (2000/20 - 60) sequences. The differentiation of tumor parenchyma from the cystic portion is easier with Gd-DTPA enhancement. After enhancement there was a reduction of measured T-1 value in all measured cases while no significant change was seen in T-2 value. No short time side effects were encountered and no significant change was seen in blood urea, creatinine, electrolytes, liver function tests, blood coagulation or urinalysis after injection of Gd-DTPA. Although much more work will be required to evaluate this contrast agent, Gd-DTPA is a promising MRI contrast enhancer for the clinical assessment of acoustic tumor. (author)