The aim of this study was to examine the prevalence, distribution, and topographic relationship of vascular ¹⁸F-sodium fluoride uptake and arterial calcification in major arteries. Methods: Image data obtained from 75 patients undergoing whole-body ¹⁸F-sodium fluoride PET/CT were evaluated retrospectively. Arterial radiotracer uptake and calcification were analyzed qualitatively and semiquantitatively. Results: ¹⁸F-sodium fluoride uptake was observed at 254 sites in 57 (76%) of the 75 study patients, and calcification was observed at 1,930 sites in 63 (84%) of the patients. Colocalization of radiotracer accumulation and calcification could be observed in 223 areas of uptake (88%). However, only 12% of all arterial calcification sites showed increased radiotracer uptake. Conclusion: Our data indicate the feasibility of ¹⁸F-sodium fluoride PET/CT for the imaging of mineral deposition in arterial wall alterations. ¹⁸F-sodium fluoride PET/CT may provide relevant information about the morphologic and functional properties of calcified plaque.

Formation and progression of atherosclerotic plaque is a dynamic and complex process involving various pathophysiologic steps including inflammation and calcification. The purpose of this study was to compare macrophage activity as determined by (18)F-FDG PET and ongoing mineral deposition as measured by (18)F-sodium fluoride PET in atherosclerotic plaque and to correlate these findings with calcified plaque burden as assessed by CT. Forty-five patients were examined by whole-body (18)F-FDG PET, (18)F-sodium fluoride PET, and CT. Tracer uptake in various arterial segments was analyzed both qualitatively and semiquantitatively by measuring the blood-pool-corrected standardized uptake value (target-to-background ratio [TBR]). The pattern of tracer uptake in atherosclerotic lesions was compared after color-coded multistudy image fusion of PET and CT studies. The Fisher exact test and the Spearman correlation coefficient r(s) were used for statistical analysis of image-based results and cardiovascular risk factors. Intra- and interrater reproducibility were evaluated using the Cohen κ. (18)F-sodium fluoride uptake was observed at 105 sites in 27 (60%) of the 45 study patients, and mean TBR was 2.3 ± 0.7. (18)F-FDG uptake was seen at 124 sites in 34 (75.6%) patients, and mean TBR was 1.5 ± 0.3. Calcified atherosclerotic lesions were observed at 503 sites in 34 (75.6%) patients. Eighty-one (77.1%) of the 105 lesions with marked (18)F-sodium fluoride uptake and only 18 (14.5%) of the 124 lesions with (18)F-FDG accumulation were colocalized with arterial calcification. Coincident uptake of both (18)F-sodium fluoride and (18)F-FDG was observed in only 14 (6.5%) of the 215 arterial lesions with radiotracer accumulation. PET/CT with (18)F-FDG and (18)F-sodium fluoride may allow evaluation of distinct pathophysiologic processes in atherosclerotic lesions and might provide information on the complex interactions involved in formation and progression of atherosclerotic plaque.

A quantitative imaging biomarker is desirable to provide a comprehensive measure of whole-body tumor burden in patients with metastatic prostate cancer, and to standardize the evaluation of treatment-related changes. Therefore, we evaluated whether prostate specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography (PET/CT) may be applied to provide PSMA-derived volumetric parameters for quantification of whole-body tumor burden. Methods: 101 patients who underwent a ⁶⁸Ga-PSMA I&T PET/CT because of increasing prostate specific antigen (PSA) levels after radical prostatectomy were included in this retrospective analysis. Tracer uptake was quantified using standardized uptake values (SUVs). Volumetric parameters, i.e. PSMA-derived tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA) were calculated for each patient using a three-dimensional segmentation and computerized volumetry technique, and compared with serum PSA levels. In a group of 10 patients, volumetric parameters were applied for treatment monitoring. Results: Volumetric parameters, i.e. whole-body PSMA-TV and whole-body TL-PSMA, demonstrated a statistically significant correlation with PSA levels (P < 0.0001) as a surrogate marker of tumor burden, whereas SUV_max (P = 0.22) or SUVmean (P = 0.45) did not. Treatment response and treatment failure were paralleled by concordant changes in both whole-body PSMA-TV and whole-body TL-PSMA (P = 0.02), whereas neither the change in SUV_max (P = 1.0) nor SUVmean (P = 1.0) concordantly paralleled changes in PSA levels. Conclusion: PSMA-derived volumetric parameters provide a quantitative imaging biomarker for whole-body tumor burden, capable of standardizing quantitative changes in PET imaging of patients with metastatic prostate cancer, and of facilitating therapy monitoring.

The purpose of this study was to correlate ¹⁸F-sodium fluoride accumulation in the common carotid arteries of neurologically asymptomatic patients with cardiovascular risk factors and carotid calcified plaque burden. Methods: Two hundred sixty-nine oncologic patients were examined by ¹⁸F-sodium fluoride PET/CT. Tracer accumulation in the common carotid arteries was analyzed both qualitatively and semiquantitatively by measuring the blood-pool–corrected standardized uptake value (target-to-background ratio) and comparing it with cardiovascular risk factors and calcified plaque burden. Results: ¹⁸F-sodium fluoride uptake was observed at 141 sites in 94 (34.9%) patients. Radiotracer accumulation was colocalized with calcification in all atherosclerotic lesions. ¹⁸F-sodium fluoride uptake was significantly associated with age (P < 0.0001), male sex (P < 0.0001), hypertension (P < 0.002), and hypercholesterolemia (P < 0.05). The presence of calcified plaque correlated significantly with these risk factors but also with diabetes (P < 0.0001), history of smoking (P = 0.03), and prior cardiovascular events (P < 0.01). There was a highly significant correlation between the presence of ¹⁸F-sodium fluoride uptake and number of present cardiovascular risk factors (r = 0.30, P < 0.0001). Conclusion: Carotid ¹⁸F-sodium fluoride uptake is a surrogate measure of calcifying carotid plaque, correlates with cardiovascular risk factors, and is more frequent in patients with a high-risk profile for atherothrombotic events but demonstrates a weaker correlation with risk factors than does calcified plaque burden. This study provides a rationale to conduct further prospective studies to determine whether ¹⁸F-sodium fluoride uptake can predict vascular events, or if it may be used to monitor pharmacologic therapy.

The detection and characterization of coronary artery stenosis and atherosclerosis using imaging tools are key for clinical decision-making in patients with known or suspected coronary artery disease. In this regard, imaging-based quantification can be improved by choosing the most appropriate imaging modality for diagnosis, treatment and procedural planning. In this Consensus Statement, we provide clinical consensus recommendations on the optimal use of different imaging techniques in various patient populations and describe the advances in imaging technology. Clinical consensus recommendations on the appropriateness of each imaging technique for direct coronary artery visualization were derived through a three-step, real-time Delphi process that took place before, during and after the Second International Quantitative Cardiovascular Imaging Meeting in September 2022. According to the Delphi survey answers, CT is the method of choice to rule out obstructive stenosis in patients with an intermediate pre-test probability of coronary artery disease and enables quantitative assessment of coronary plaque with respect to dimensions, composition, location and related risk of future cardiovascular events, whereas MRI facilitates the visualization of coronary plaque and can be used in experienced centres as a radiation-free, second-line option for non-invasive coronary angiography. PET has the greatest potential for quantifying inflammation in coronary plaque but SPECT currently has a limited role in clinical coronary artery stenosis and atherosclerosis imaging. Invasive coronary angiography is the reference standard for stenosis assessment but cannot characterize coronary plaques. Finally, intravascular ultrasonography and optical coherence tomography are the most important invasive imaging modalities for the identification of plaques at high risk of rupture. The recommendations made in this Consensus Statement will help clinicians to choose the most appropriate imaging modality on the basis of the specific clinical scenario, individual patient characteristics and the availability of each imaging modality.