SPECT versus planar liver scintigraphy: is SPECT worth it?

Five hundred three planar and SPECT hepatic studies were reviewed separately by two experienced observers looking for focal disease. An equivocal reading meant referral to ultrasound or computed tomography (US/CT). The increase in correct readings and decrease in US/CT referrals per 100 positive and per 100 negative SPECT readings were calculated, then the increase in correct readings and decrease in US/CT referrals for various positive rates of liver involvement determined. At our institution, the overall positive rate is approximately 13% yielding 1.1 and 0.83 more correct readings and 1.8 and 2.0 fewer US/CT referrals per 100 cases for each reader, respectively; a marginal benefit for SPECT over planar scintigraphy.