L1 vertebral density on CT is too variable with different scanning protocols to be a useful screening tool for osteoporosis in everyday practice.

Objective: To determine whether a single L1 density threshold can be used to screen all patients undergoing CT at a busy tertiary referral centre for those at risk of osteoporosis.

Methods: 200 patients, who had been randomly selected for an audit of CT reporting of incidental vertebral fractures, had their L1 density measured on 864 routine CT examinations. These had been performed with a variety of kVp and intravenous (i.