18F-fluoride uptake in bone metastasis: morphologic and metabolic analysis on integrated PET/CT

Comparison of the Relative Diagnostic Performance of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT for the Detection of Bone Metastasis in Patients With Different Cancers

Purpose

The present retrospective analysis sought to compare the relative diagnostic efficacy of [⁶⁸Ga]Ga-DOTA-FAPI-04 to that of [¹⁸F]FDG PET/CT as a means of detecting bone metastases in patients with a range of cancer types.

Materials

In total, 30 patients with bone metastases associated with different underlying malignancies were retrospectively enrolled. All patients had undergone [⁶⁸Ga]Ga-DOTA-FAPI-04 and [¹⁸F]FDG PET/CT, and the McNemar test was used to compare the relative diagnostic performance of these two imaging modalities. The maximum standard uptake value (SUVmax) was used to quantify radiotracer uptake by metastatic lesions, with the relative uptake associated with these two imaging strategies being compared via the Mann-Whitney U test. The cohort was further respectively divided into two (osteolytic and osteoblastic bone metastases) and three clinical subgroups (lung cancer, thyroid cancer, and liver cancer).

Results

[⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT was found to be significantly more sensitive as a means of diagnosing bone metastases relative to [¹⁸F]FDG PET/CT ([109/109] 100% vs [89/109] 81.7%; P< 0.01), consistent with the significantly increased uptake of [⁶⁸Ga]Ga-DOTA-FAPI-04 by these metastatic lesions relative to that of [¹⁸F]FDG (n=109, median SUVmax, 9.1 vs. 4.5; P< 0.01). [⁶⁸Ga]Ga-DOTA-FAPI-04 accumulation was significantly higher than that of [¹⁸F]FDG in both osteolytic (n=66, median SUVmax, 10.6 vs 6.1; P < 0.01), and osteoblastic metastases (n=43, median SUVmax, 7.7 vs 3.7; P < 0.01). [⁶⁸Ga]Ga-DOTA-FAPI-04 uptakes were significantly higher than that of [¹⁸F]FDG in bone metastases from lung cancer (n = 62, median SUVmax, 10.7 vs 5.2; P < 0.01), thyroid cancer (n = 18, median SUVmax, 5.65 vs 2.1; P < 0.01) and liver cancer (n = 12, median SUVmax, 5.65 vs 3.05; P < 0.01). However, [⁶⁸Ga]Ga-DOTA-FAPI-04 detected 10 false-positive lesions, while only 5 false-positive were visualized by [¹⁸F]FDG PET/CT.

Conclusion

[⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT exhibits excellent diagnostic performance as a means of detecting bone metastases, and is superior to [¹⁸F]FDG PET/CT in this diagnostic context. Furthermore, [⁶⁸Ga]Ga-DOTA-FAPI-04 tracer uptake levels are higher than those of [¹⁸F]FDG for most bone metastases. However, owing to the potential for false-positive bone lesions, it is critical that physicians interpret all CT findings with caution to ensure diagnostic accuracy.

Differential diagnostic value of 18F-FDG PET/CT in osteolytic lesions

Background

Both bone metastases and multiple myeloma (MM) are malignant diseases that can appear osteolytic on imaging and are difficult to differentiate. While positron emission tomography/computed tomography (PET/CT) has been demonstrated useful for the diagnosis of various bone lesions, correlations between PET/CT and histopathology and these diseases are unclear. This retrospective study investigated the optimal cutoff standardized uptake value (SUV) to differentiate MM and bone metastasis.

Methods

Patients with newly diagnosed osteolytic lesions (n = 344) and suspected malignancy underwent both fluorodeoxyglucose (FDG) PET/CT and biopsy/surgery. FDG uptake and morphologic changes (e.g., soft tissue mass formation) were compared with pathological results.

Results

A total of 8896 osteolytic lesions were evaluated. The SUVmax of MM osteolytic lesions (1.6 ± 0.7) was significantly lower than that of bone metastases (5.5 ± 2.7; p = 0.000). The best cutoff SUVmax for differentiating MM and bone metastasis was 2.65 (sensitivity 86.1%, specificity 94.7%; p = 0.000). The SUVmax of bone lesions of soft tissue mass was higher than that for pure osteolytic lesions (p = 0.000). A greater percentage of patients with bone metastasis had a soft tissue mass (7%) than did patients with MM (2%). The mean SUVmax of bone metastases was 5.5 ± 2.7 (0.4-30.4); that of primary tumors was 7.5 ± 4.2 (1.0-28.5). The SUVmax of bone metastases significantly correlated with the SUVmax of primary tumors (r = 0.532; p = 0.000).

Conclusions

FDG PET/CT is a valuable tool to differentiate osteolytic lesions. The best cutoff value of SUVmax for differentiating MM from bone metastasis is 2.65. The significant correlation between the SUVmax of bone metastasis and that of primary tumors is helpful for detecting primary tumors.

18F-Sodium Fluoride PET: History, Technical Feasibility, Mechanism of Action, Normal Biodistribution, and Diagnostic Performance in Bone Metastasis Detection Compared with Other Imaging Modalities

The skeleton is the third most common site for metastasis overall, after the lungs and liver. Accurate diagnosis of osseous metastasis is critical for initial staging, treatment planning, restaging, treatment monitoring, and survival prediction. Currently, ^99mTc-methylene diphosphonate whole-body scanning is the cornerstone of imaging to detect osseous metastasis. Although ¹⁸F-sodium fluoride (¹⁸F-NaF) was one of the oldest medical tracers for this purpose, it was replaced by other tracers because of their better physical properties, until recently. Continued development of PET scanners has opened a new era for ¹⁸F-NaF, and given its higher sensitivity, there have been increasing applications in imaging. In this review, we will discuss the history, technical aspects, radiobiology, and biodistribution of this tracer. Finally, we compare the accuracy of ¹⁸F-NaF PET with other conventional imaging methods for detection of osseous metastasis.

(18)F-NaF PET/CT: EANM procedure guidelines for bone imaging

The aim of this guideline is to provide minimum standards for the performance and interpretation of (18)F-NaF PET/CT scans. Standard acquisition and interpretation of nuclear imaging modalities will help to provide consistent data acquisition and numeric values between different platforms and institutes and to promote the use of PET/CT modality as an established diagnostic modality in routine clinical practice. This will also improve the value of scientific work and its contribution to evidence-based medicine.

Review of the role of dynamic 18F-NaF PET in diagnosing and distinguishing between septic and aseptic loosening in hip prosthesis

Joint replacements may fail due to infection, dislocation, peri-prosthetic fracture and loosening. Between 0.4 and 4% of joint replacements are known to be complicated by infection and aseptic loosening 2–18%. Differentiating between infection and aseptic loosening has an important bearing on the ongoing strategy for antimicrobial therapy and surgical intervention, but distinguishing one from the other can be difficult and will often require a battery of clinical and biochemical tests including the use of varying radiological modalities to accurately identify whether problematic joints are infected or aseptically loose. Prompt diagnosis is important due to the development of a biofilm on the surface of the infected prosthesis, which makes treatment difficult. There is no consensus among experts on the ideal imaging technique nor the methodology for image interpretation, but there is an increasing trend to apply hybrid imaging in the investigation of painful joint prosthesis and recent attempts have been made using PET-CT to identify aseptic loosening and infection with ¹⁸F-fluorodeoxyglucose (FDG) and sodium fluoride ¹⁸F-Na. The aim of this paper is to evaluate the role of ¹⁸F-NaF sodium fluoride (¹⁸F-NaF) positron emission tomography (PET) in distinguishing between septic and aseptic failure in hip and knee replacements, in addition to evaluating the feasibility of using multi-sequential ¹⁸F-NaF PET-CT for the assessment of painful lower limb prostheses.

Correlation between mechanical stress by finite element analysis and 18F-fluoride PET uptake in hip osteoarthritis patients

18F-fluoride positron emission tomography (18F-fluoride PET) is a functional imaging modality used primarily to detect increased bone metabolism. Increased 18F-fluoride PET uptake suggests an association between increased bone metabolism and load stress at the subchondral level. This study therefore examined the relationship between equivalent stress distribution calculated by finite element analysis and 18F-fluoride PET uptake in patients with hip osteoarthritis. The study examined 34 hips of 17 patients who presented to our clinic with hip pain, and were diagnosed with osteoarthritis or pre-osteoarthritis. The hips with trauma, infection, or bone metastasis of cancer were excluded. Three-dimensional models of each hip were created from computed tomography data to calculate the maximum equivalent stress by finite element analysis, which was compared with the maximum standardized uptake value (SUVmax) examined by 18F-fluoride PET. The SUVmax and equivalent stress were correlated (Spearman's rank correlation coefficient ρ=0.752), and higher equivalent stress values were noted in higher SUVmax patients. The correlation between SUVmax and maximum equivalent stress in osteoarthritic hips suggests the possibility that 18F-fluoride PET detect increased bone metabolism at sites of stress concentration. This study demonstrates the correlation between mechanical stress and bone remodeling acceleration in hip osteoarthritis.

Role of (18)F-fluoride PET/CT over dual-phase bone scintigraphy in evaluation and management of lesions causing foot and ankle pain

OBJECTIVE

The purpose of this study was to assess the potential role of (18)F-fluoride PET/CT over dual-phase bone scintigraphy (DBS) in evaluation and management of lesions causing foot and ankle pain.

METHODS

(99m)Tc-HDP DBS and (18)F-fluoride PET/CT were performed in consecutive patients who visited rehabilitation department due to foot or ankle pain. Focal painful lesions in fore, mid, and hindfoot or ankle, and diffuse pain in foot were evaluated on DBS and (18)F-fluoride PET/CT (conclusive, inconclusive, nonvisible) and lesions on each modality were correlated. The clinical course was followed to see if the results of (18)F-fluoride PET/CT affected the decision of patient management.

RESULTS

Sixty-one painful lesions in 31 patients included 16 forefoot (26.2 %), 11 midfoot (18.0 %), 19 hindfoot (31.2 %), 6 ankle (9.8 %), and 9 diffuse footpain (14.8 %). Forty lesions (40/61, 65.6 %) were detected on DBS, including 21 conclusive diagnostic (21/40, 52.5 %), mainly including hindfoot lesions (n = 11). The inconclusive 19 lesions (19/40, 47.5 %) on DBS showed conclusive diagnostic findings on (18)F-fluoride PET/CT, mainly in fore and midfoot lesions (n = 15). Twenty-one painful lesions (21/61, 34.4 %) which were nonvisible on DBS revealed conclusive diagnostic findings on (18)F-fluoride PET/CT in 7 lesions (7/21, 33.3 %), including 5 hindfoot lesions. Fourteen nonvisible lesions (14/21, 66.7 %) on both modalities included all 9 diffuse painful foot lesions. Patient management was affected by findings of (18)F-fluoride PET/CT in 31 lesions (31/61, 50.8 %).

CONCLUSIONS

(18)F-fluoride PET/CT provided more confirmative diagnostic information in painful foot and ankle over DBS, and influenced patient management in many inconclusive or nonvisible cases on DBS. Increasing role of (18)F-fluoride PET/CT in benign diseases including foot and ankle pain is expected in the near future.

18F-Fluoride PET/CT allows detection of hyperostosis and osseous involvement in meningioma: initial experience

PURPOSE

The present study was conducted to assess the diagnostic performance of (18)F-fluoride PET/CT in evaluating hyperostosis and osseous involvement in patients with meningioma.

PATIENTS AND METHODS

Thirty-four patients with meningioma (mean age, 61 years) underwent (18)F-fluoride PET/CT before surgery. In 24 patients (71%), (18)F-FDG PET/CT was also given before surgery, and the results were compared. The images were reviewed by 2 board-certified nuclear medicine specialists who were unaware of any clinical information and a consensus was reached. Uptake patterns and measurements of tracers were compared with pathological findings from resected specimens, with hyperostosis and osseous involvement as the reference standard.

RESULTS

There were 27 grade I tumors (79%) and 7 grade II tumors (21%). The primary tumor focus was identified in each patient using both (18)`F-fluoride PET/CT and (18)F-FDG PET/CT, but there were no significant correlations in the degree of uptake between the 2 tracers. The SUV(max), SUV(max) corrected for lean body mass (SUL(max)), and tumor metabolic volume (TMV) for (18)F-fluoride and (18)F-FDG were greater in grade II tumors than in grade I tumors. Hyperostosis and osseous involvement was identified in 12 tumors (38%). The SUV(max), SUL(max), and TMV of tumors visualized with (18)F-fluoride PET/CT were greater in tumors with hyperostosis and osseous involvement than in those without (P = 0.005, P = 0.003, and P = 0.006, respectively). In contrast, the SUV(max), SUL(max), and TMV of tumors visualized with (18)F-FDG PET/CT were similar regardless of hyperostosis or osseous involvement.

CONCLUSIONS

(18)F-fluoride PET/CT may improve detection of hyperostosis and osseous involvement in patients with meningioma.

Bone metastases from prostate cancer: 18F-fluoride PET/CT in a patient with discordant bone scintigraphy and 11C-choline PET/CT

Bone scintigraphy has been used extensively in prostate cancer patients to detect bone involvement. (11)C-choline PET/CT is indicated when a biochemical recurrence is suspected, as this procedure is able to detect local recurrence, lymph-node infiltration, and metastases.In cases where the results of these 2 procedures do not coincide, MRI is then usually performed. (18)F-fluoride may become an alternative to MRI for bone imaging.In our patient series, all bone lesions with (11)C-choline uptake were metastases. (18)F-Fluoride did not increase specificity of (11)C-choline but increased sensitivity of bone scintigraphy. CT helped in the interpretation of osteoarthritis and trauma lesions.

Impact of ¹⁸F-fluoride PET-CT on implementing early treatment of painful bone metastases with Sm-153 EDTMP

This study evaluated the diagnostic impact of using skeletal (18)F-fluoride PET/CT on patients with painful bone metastases to schedule an early palliative radionuclide treatment.

METHODS

The skeletal involvement from prostate cancer metastases was assessed by both (99m)Tc-diphosphonate bone scan (BS) and (18)F-fluoride PET/CT within four weeks in 24 patients (67.7 ± 5.1 years) suffering from a borderline degree of bone pain for which radionuclide palliation was not shortly planned for administration. The BS and (18)F-fluoride PET/CT results were compared, assessing the number and extension of the skeletal sites involved. Afterward, the patients were randomly assigned either to the study group (N=12) receiving radionuclide therapy (Samarium-153 EDTMP) or to the control group (N=12) not receiving radionuclide therapy. The short-term results from the radionuclide palliation group (evaluated with a visual analogue scale) were compared with the controls.

RESULTS

Overall, at BS, 7.6 ± 1.4 sites were considered metastatic, involving at least 5 ± 1 body regions. At (18)F-fluoride PET/CT, 116 ± 19 sites presented metastatic involvement with 12/12 body regions concerned. No differences were found in regards to either the number of metastatic sites or regions at both BS and (18)F-fluoride PET/CT between the study group and controls (p=ns). At CT, 88 blastic metastases were identified, whereas 110 were mainly lytic. Most of mainly lytic lesions were not detectable at BS. The reduction in total discomfort and bone pain in the study group was significantly greater than in the controls (p<0.0001).

CONCLUSION

Sm-153 EDTMP therapy should be considered for patients with early bone pain from prostate cancer even if their BS only indicates a few metastases before the initiation of a severe pain syndrome. (18)F-fluoride PET/CT may be helpful in deciding if the implementation of bone pain palliation using bone-seeking radionuclides at pain onset is necessary.

Molecular imaging of prostate cancer: PET radiotracers

OBJECTIVE

Recent advances in the fundamental understanding of the complex biology of prostate cancer have provided an increasing number of potential targets for imaging and treatment. The imaging evaluation of prostate cancer needs to be tailored to the various phases of this remarkably heterogeneous disease.

CONCLUSION

In this article, I review the current state of affairs on a range of PET radiotracers for potential use in the imaging evaluation of men with prostate cancer.

Radionuclide imaging in the diagnosis and management of orthopaedic disease

Nuclear medicine imaging is often used in the diagnosis and management of several orthopaedic conditions. Bone scintigraphy measures gamma ray emission to detect the distribution of an injected radiolabeled tracer on multiple image projections. In general, this imaging modality has relatively high sensitivity but low specificity in the diagnosis of occult fractures, bone tumors, metabolic bone disease, and infection. Positron emission tomography measures tissue metabolism and perfusion by detecting short half-life positron ray emission of an injected radiopharmaceutical tracer. Historically, positron emission tomography has been used only to monitor bone metastasis and aid in the diagnosis of osteomyelitis; however, this technology has recently been applied to other orthopaedic conditions for which current imaging modalities are insufficient.

Clinical utility of (18)F-fluoride PET/CT in benign and malignant bone diseases

(18)F labeled sodium fluoride is a positron-emitting, bone seeking agent with more favorable skeletal kinetics than conventional phosphate and diphosphonate compounds. With the expanding clinical usage of PET/CT, there is renewed interest in using (18)F-fluoride PET/CT for imaging bone diseases. Growing evidence indicates that (18)F fluoride PET/CT offers increased sensitivity, specificity, and diagnostic accuracy in evaluating metastatic bone disease compared to (99m)Tc based bone scintigraphy. National Oncologic PET Registry (NOPR) has expanded coverage for (18)F sodium fluoride PET scans since February 2011 for the evaluation of osseous metastatic disease. In this article, we reviewed the pharmacological characteristics of sodium fluoride, as well as the clinical utility of PET/CT using (18)F-fluoride in both benign and malignant bone disorders.

A meta-analysis of (18)F-Fluoride positron emission tomography for assessment of metastatic bone tumor

PURPOSE

The aim of this study was to assess the diagnostic performance of (18)F-Fluoride positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) compared with bone scintigraphy (BS) planar or BS planar and single photon emission computed tomography (SPECT) in evaluating patients with metastatic bone tumor.

MATERIALS AND METHODS

We performed a meta-analysis of all available studies addressing the diagnostic accuracy of (18)F-Fluoride PET, (18)F-Fluoride PET/CT, BS planar, and BS planar and SPECT for detecting the metastatic bone tumor. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios, and drew summary receiver operating characteristic curves using hierarchical regression models. We also compared the effective dose and cost-effectiveness estimated by data from the enrolled studies between (18)F-Fluoride PET or PET/CT and BS planar or BS planar and SPECT.

RESULTS

When comparing all studies with data on (18)F-Fluoride PET or PET/CT, sensitivity and specificity were 96.2% [95% confidence interval (CI) 93.5-98.9%] and 98.5% (95% CI 97.0-100%), respectively, on a patient basis and 96.9% (95% CI 95.9-98.0%) and 98.0% (95% CI 97.1-98.9%), respectively, on a lesion basis. The Az values of (18)F-Fluoride PET or PET/CT were 0.986 for the patient basis and 0.905 for the lesion basis, whereas those of BS or BS and SPECT were 0.866 for the patient basis and 0.854 for the lesion basis. However, the estimated effective dose and average cost-effective ratio were poorer for (18)F-Fluoride PET or PET/CT than those of BS planar or BS planar and SPECT.

CONCLUSION

(18)F-Fluoride PET or PET/CT has excellent diagnostic performance for the detection of metastatic bone tumor, but the estimated effective dose and average cost-effective ratio are at a disadvantage compared with BS planar or BS planar and SPECT.