18F-sodium fluoride bone PET-CT in symptomatic lumbosacral transitional vertebra

AIM: To analyse the relationship between F-18-labelled sodium fluoride (NaF) uptake and lumbar back pain in patients with lumbosacral transitional vertebra (LSTV) a congenital malformation of the lumbosacral spine. MATERIALS AND METHODS: The study population comprised 55 patients (mean age, 51.42 years; median age 52 years) with LSTV. All patients underwent integrated positron-emission tomography (PET)/computed tomography (CT) by injecting 0.06 mCi/kg of F-18-NaF. A threepoint grading system was used to evaluate F-18-NaF uptake (grade 0, no uptake; grade 1, mild uptake; and grade 2, marked increase uptake. RESULTS: In total, 55 cases of LSTV (34 symptomatic and 21 asymptomatic) were included. Asymptomatic patients had no uptake in the majority of cases, i.e., grade 0 (n=18) and grade 1 (n=3), whereas symptomatic patients demonstrated focal increase tracer uptake of grade 2 (n=24), grade 1 (n=4), and grade 0 (n=6). There is a strong linear trend between the intensity of F-18-NaF uptake and presence of symptoms (p<0.0001). The sensitivity and specificity of F-18-NaF uptake at LSTV as a cause of pain were 82% (95% confidence interval [CI]: 65e93%) and 86% (95% CI: 64-97%). The positive and negative predictive values were 90% (95% CI: 74-98%) and 75% (95% CI: 53e90%). CONCLUSIONS: F-18-NaF PET/CT can be useful in evaluating back pain and F-18-NaF may be used as an adjunctive biological maker for assessing LSTV as a potential cause of pain. (C) 2020 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.