Precision of ultrasonic estimates of choroidal melanoma regression.

BACKGROUND

Important prognostic information may be gained from knowledge of the volume and, over time, the change in volume of intraocular tumors such as choroidal melanomas.

METHODS

The precision and time consumption of three different ultrasonographic methods were evaluated. Seven choroidal melanomas were analysed after placement of a ruthenium plaque and again after tumor regression had occurred. Perpendicular ultrasound B-scans were printed and analysed by overlay grid counting or outline tracing of tumor structures to calculate the volume. These two methods, using only two perpendicular scans, were compared with a micro-computer-controlled ultrasonographic three-dimensional rotation scanning system, where each tumor was manually outlined in 20 revolving scan planes

RESULTS

The three-dimensional volume scanning method was the most precise, but also the most demanding in hardware and time consumption.

CONCLUSION

Increased precision and less observer-dependent estimation of shrinkage rate after radiotherapy is available at the cost of sophisticated equipment.