ACOUSTIC NEUROMA VOLUME - MRI-BASED CALCULATIONS AND CLINICAL IMPLICATIONS

This study developed a technique for magnetic resonance imaging (MRI)- based volume calculation and defined the specific volume-diameter rela tionship in acoustic neuromas (AN). Computer-assisted measurement calc ulated the area of tumor in each MRI slice. Volume was determined by m ultiplying area by slice interval. The technique was validated by imag ing known volumes of gadolinium. The precision was greater than 95%. O ur volume calculations revealed a specific volume-diameter relationshi p in ANs. The following conclusions can be drawn: 1. our technique can accurately determine AN tumor volume; 2. the AN volume-diameter relat ionship is a specific function and cannot be predicted by assumptions of tumor shape; 3. the volume-diameter relationship should be combined with clinical data to determine the ''break point'' at which small in crements of diameter produce significant clinical sequelae.