Purpose To determine whether SIJ & sup1;F-8-NaF uptake is associated with MRI-defined inflammation and structural damage and whether it provides a complementary measure of osteoblastic disease burden. Methods In this prospective exploratory study, 43 adults with chronic low back pain underwent pelvic radiography, sacroiliac joint (SIJ)-MRI, and whole-body & sup1;F-8-NaF PET/CT and were classified as having radiographic axial spondyloarthritis or ankylosing spondylitis (AS; n = 29), non-radiographic axial spondyloarthritis (nr-axSpA; n = 5), or degenerative joint disease (DJD; n = 9). MRI was evaluated using SPARCC inflammation and structural scores. SIJ uptake was assessed visually and quantified using SUVmax. The primary endpoint was the correlation between SIJ SUVmax and the SPARCC structural score. Results SIJ SUVmax correlated with the SPARCC inflammation (rho = 0.629) and structural (rho = 0.606) scores (both p < 0.001) on SIJ-MRI; both associations persisted after mutual adjustment. Median SIJ SUVmax differed across AS, nr-axSpA, and DJD (14.7 [11.2-22.4], 5.5 [4.4-9.9], and 5.7 [4.0-9.2], respectively; p = 0.001). Visually positive uptake occurred in 23/29 (79.3%) patients with AS, including 10/16 without MRI-defined bone marrow edema; no patient with AS had edema without increased uptake. Peripheral joint and entheseal uptake were frequent but non-discriminatory. Exploratory AUCs were 0.841 for AS versus DJD and 0.848 for AS versus nr-axSpA. Conclusion SIJ & sup1;F-8-NaF uptake was associated with both MRI-defined inflammation and structural burden in patients with AS, including those without active inflammation on MRI. SIJ SUVmax warrants evaluation as a complementary quantitative imaging biomarker of osteoblastic disease burden, but all derived thresholds require external validation.
Purpose To develop and preliminarily validate a multiparametric diagnostic model integrating & sup1;F-8-meta-fluorobenzylguanidine (& sup1;F-8-MFBG) PET/CT imaging parameters with clinical factors for noninvasive differentiation of neuroblastoma (NB) from ganglioneuroblastoma (GNB) in pediatric patients. Methods This retrospective study enrolled 42 pediatric patients with histologically confirmed NB (n = 23) or GNB (n = 19) who underwent & sup1;F-8-MFBG PET/CT prior to treatment. Quantitative imaging parameters and clinical data were extracted. Correlations were assessed using Spearman's rank correlation coefficient. Multicollinearity among predictors was evaluated using variance inflation factors (VIF). Univariate and multivariable Firth logistic regression analyses were performed to identify independent predictors. The discriminative performance of the model was evaluated via receiver operating characteristic (ROC) analysis, the DeLong test, bootstrap validation, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Results SUVmax, SUVmean, TBRmean, TBRmax, AUC-CSH and TL-hNET differed significantly between NB and GNB(P < 0.05). Severe multicollinearity (VIF > 10) was observed among imaging parameters, SUVmax was selected for multivariable modeling, along with age, bone metastasis and 11q23 deletion as the strongest clinical predictors. In the multivariable Firth model, SUVmax (OR = 8.665; P = 0.029) and age (OR = 0.676; P = 0.043) remained independently associated with NB. Bone metastasis showed a trend toward independent association with NB (OR = 11.753; P = 0.050), with the association approaching statistical significance. Three diagnostic models were constructed and compared: (1) imaging-only model (SUVmax); (2) clinical-factor model (age + bone metastasis); and (3) integrated model (SUVmax + age + bone metastasis). The combined model achieved an AUC of 0.856(95%CI:0.737-0.975), showing a trend toward improved discrimination compared with both the SUVmax-only model (AUC = 0.810, 95%CI:0.668-0.952) and the clinical-factor model (AUC = 0.787, 95%CI:0.659-0.916). Bootstrap validation (2000 resamples) and IDI analysis provided supportive evidence of incremental value of the integrated model (Combined vs. SUVmax-only: IDI = 0.122, P = 0.014; Combined vs. clinical: IDI = 0.083, P = 0.045). Conclusion The multiparametric model integrating & sup1;F-8-MFBG PET/CT imaging parameters with clinical factors generated a promising preliminary hypothesis for diagnostic performance for differentiating NB from GNB, pending rigorous external validation in larger, multicenter cohorts.
