Abstract P2-05-01: A Comparative Study of 18F-Fluoride PET/CT and Whole-Body High Resolution CT (HRCT) for the Detection of Bone Metastases in Patients with Advanced Breast Cancer
Authors: DeCensi A , Piccardo A , Altrinetti V , Bacigalupo L , Biscaldi E , Bianchi P , Barbera F , Cabria M , Camti C , Zanardi S , Campora S , Puntoni M , Rollandi GA , Villavecchia G. E.O. 
Published: April 2011

Abstract
Background: Bone scintigraphy (BS) have been shown to be of value in detecting bone metastases several months before conventional radiography, whereas computed tomography (HRCT) and magnetic resonance imaging (MRI) can reveal more metastases in the spine than conventional BS. 18F-Fluoride PET has been shown to be more accurate than BS for the detection bone lesions in different malignancies and has been suggested as an alternative to BS. Recent studies have shown that integrated 18F-Fluoride-PET/CT is both sensitive and specific for detection of lytic and sclerotic lesions and is superior to 18F-Fluoride PET. The aim of our study is to evaluate the diagnostic accuracy of 18F-Fluoride-PET/CT in comparison to HRCT for the detection of bone metastases in breast cancer patients.
Material and methods: The study involved 39 patients with breast cancer with known bone metastases or at high risk for its presence. All patients presented indications for skeletal surveys. Imaging was performed on an integrated PET/CT system. All PET scans were acquired in 2D mode and were reconstructed using an iterative reconstruction algorithm; diagnostic HRCT data of PET/CT were acquired for detecting bone lesions and were used for attenuation correction. PET acquisition started 60 min after intravenous injection of 370-550 MBq 18F-labelled NaF and included 10-12 bed positions.
The interpretation of PET/CT and High resolution CT studies was made as a consensus reading of two nuclear medicine physicians and a radiologist who had access to clinical, as well as previous radiological imaging information. 12 months follow-up based on previous and/or following imaging studies was considered the gold standard. Results: Overall 671 bone lesions were detected in our analysis including both PET/CT and CT results. Of these lesions 530 malignant, 32 equivocal and 109 benign were classified by consensus reading. 18F-Fluoride PET/CT detected 491 bone metastases, 114 (23%) of which without any clear morphological changes on CT. HRCT detected 416 bone metastases, 39 (9.3%) of which without any 18F-fluoride uptake. The overall sensitivity and specificity was 90% and 91% for 18F-Fluoride-PET/CT and 79 and 93% for HRCT, respectively. In a patients based analysis both 18F-Fluoride-PET/CT and HRCT identified the same number of patients with bone metastases (27 of 39).
Conclusions: Our data show a high agreement (71% of lesions and 100% of the patients) between 18F-Fluoride-PET/CT and HRCT for bone metastases detection. However integrated analysis of 18F-Fluoride-PET/HRCT has the best diagnostic option to evaluate bone involvement in breast cancer, and 18F-Fluoride-PET/CT seems to have the highest sensitivity. Follow-up is ongoing to assess the prognostic/predictive value of 18F-Fluoride-PET/CT.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-05-01.