PT - JOURNAL ARTICLE AU - Nakahara, Takehiro AU - Narula, Jagat AU - Agarwal, Sunil AU - Chowdhury, Mohammed AU - Coughlin, Patrick AU - Dweck, Marc AU - Rudd, James AU - Mulhall, John AU - Strauss, H. William TI - <strong><sup>18</sup>F-fluoride uptake in Penile Arteries and Erectile Dysfunction<sup> </sup></strong> DP - 2018 May 01 TA - Journal of Nuclear Medicine PG - 299--299 VI - 59 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/59/supplement_1/299.short 4100 - http://jnm.snmjournals.org/content/59/supplement_1/299.full SO - J Nucl Med2018 May 01; 59 AB - 299Objectives: Erectile dysfunction (ED) and atherosclerosis share common risk factors1-3. To determine if atherosclerosis plays a role in ED we analyzed Fluorine-18 sodium fluoride (NaF)-PET/CT images in prostate cancer patients. Although NaF is a bone-seeking radiopharmaceutical used to detect osseous metastases, recent studies showed its utility for detection of lipid-rich atherosclerotic lesions4-7. We hypothesized that NaF uptake in penile vessels could serve as an early marker of vascular involvement, which might form a basis of vasculogenic (arterial or cavenosal) ED. In this study, we evaluated the prevalence of penile vascular NaF uptake in patients with and without ED. Methods: NaF-PET/CT bone scans were evaluated in 437 prostate cancer patients (age 66.6±8.7 years). Their urologic histories were reviewed to determine ED at the time of initial scans (Prevalent ED, ED diagnosed before the date of scan), or during one year of follow up (Incident ED, no ED at the time of the first scan, but developed during 1-year follow-up), and patients with no ED (No ED, neither before the scan date nor during follow-up, the control group). A semicircular ROI was set on the dorsal half of the penis (to avoid residual excretory activity in the urethra) on 5 contiguous slices at the base of penis on PET/CT coronal reconstructions. The average SUVmax of 5 ROI was defined as NaF uptake. A subset of patients also underwent 18F-fluorodeoxyglucose (FDG)-PET/CT scans within 6 months of the NaF scan and allowed analysis of the relationship between NaF and FDG; FDG is considered the inflammatory marker of atherosclerosis. Non-parametric data were presented as median (interquartile range, IQR; i.e. 25th to 75th percentile, or Q1,Q3) and compared using Wilcoxon scores (rank sums) test. The Pearson coefficient of correlation test was used for the assessment of linear correlation of two parameters. The areas under curve (AUC) of receptor operating characteristic (ROC) curve were used to compare incremental diagnostic utility of NaF for diagnosis of Prevalent ED or Incident ED. Unadjusted rate of ED was estimated for each parameter. A two-sided p &lt;0.05 was considered statistically significant. Results: Of 437 patients with prostate mailgnancy, 336 (76.9%) had Prevalent ED, 60 Incident ED (13.7%), and 41 had no ED (9.4%). SUVmax in Prevalent (median 1.87; IQR 1.67-2.16) or Incident (1.86; 1.72-2.08) ED was significantly higher than No ED (1.42; 1.25-1.54) patients (p&lt;0.001). After adjustment for other risk factors, the odds of prevalent or incident ED was 540.5 (89.3-3269.2) for each unit increment in SUVmax, with ROC area of 0.91 (95%CI: 0.88-0.94) for ED. A subset of 63 patients who had both FDG-PET/CT and NaF-PET/CT scans within 6 months of each other showed no significant difference of FDG uptake in the No ED, Incident ED, or Prevalent ED patients. There was no significant correlation between NaF uptake and FDG uptake. ROC analysis showed higher diagnostic value of NaF uptake for Incident ED or Prevalent ED than FDG (NaF uptake AUC: 0.934, 95%C.I. 0.846-1.021 vs FDG uptake AUC: 0.682, 95%C.I. 0.439-0.926). Conclusions: Fluoride uptake in penile vessels is significantly higher in patients with Prevalent or Incident ED. NaF uptake occurs both in patients undergoing surgical or radiation therapy. Future studies should examine the role of penile vascular fluoride uptake as a contributor to ED in a general, non-malignancy subject population. Research Support: SNMMI Wagner-Torizuka Fellowship and Uehara Memorial Foundation to TN.