Detection of bone metastases through diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) compared with PET/CT 18F-NaF.

Abstract

e23086 Background: To evaluate a diagnostic test which can allow the comparison between Diffusion-weighted imaging with background suppression (DWIBS) the novel diagnostic modality versus PET/CT 18F-NaF, the gold standard for the diagnosis of bone metastases (BM). Methods: University bioethics committee authorized the protocol. Patients with solid cancer and suspicion of BM (by clinical findings, imaging, and tumor biomarkers), who met inclusion criteria were included and provided their signed informed consent. The DWIBS in a MR 3.0 T was performed first and then the PET/CT 18F-NaF. Each study was interpreted blinded. Statistics to evaluate a diagnostic test were performed. Results: From April 2014 to April 2016, 91 patients (100%) were interviewed, 88 (93.4%) met the inclusion criteria. Nine patients (8%) were excluded: death 3, respiratory failure 2, refused participating 2, pacemaker 1, claustrophobia 1. Seventy-nine patients (86.8%) were included, of which 81.0% (64/79) were women. Primary cancer was: a) breast 73.4 b) prostate 15.2%; c) Non-Hodgkin lymphoma 2.5%; d) cervical 2.5%; e) thyroid 2.5%; f) lung 1.3%; g) colon 1.3%; and h) testicular 1.3%. Diagnostic performance of DWIBS compared to PET/CT 18F-NaF, sensitivity 88.1% (Confidence Interval [CI95%, 73.3-96.0), specificity of 48.7% (CI 95%, 31.9-65.6), PPV of 66.0% (CI 95%, 58.2-73.1), NPV of 78.3% (CI 95%, 59.7-89.7), PLR 1.7 (CI 95%, 1.2-2-4), NLR 0.2 (CI 95%, 0.1-0.6) and prevalence of 53.1% (CI 95%, 41.6-54.5). Results were stratified in quartiles (excellent, good, fair, and poor). Conclusions: DWIBS has excelent sensibility, fair specificity, good PPV, and excellent NPV. These data suggest DWIBS could be used as a proxy of PET/CT 18F-NaF.