(18)F-FDG PET/CT for Diagnosis of Osteosclerotic and Osteolytic Vertebral Metastatic Lesions: Comparison with Bone Scintigraphy

Diagnostic accuracy of imaging modalities for detection of spinal metastases: a systematic review and meta-analysis

PURPOSE

Detecting spinal metastases is highly relevant in patients with oncological disorders as it can affect the staging and treatment of their disease. We aimed to evaluate the diagnostic performance of computed tomography (CT), magnetic resonance imaging (MRI), FDG positron emission tomography (PET)/CT, bone scintigraphy (BS), and single-photon emission computed tomography (SPECT) for spinal metastases detection.

METHODS

Medline, EMBASE, and Web of Science were systematically searched until March 2024 for diagnostic accuracy studies on spinal metastases detection (PROSPERO-registration: CRD42024540139). Data extraction and quality assessment using the QUADAS-2 tool were performed by two independent reviewers. Using bivariate random effects modeling, pooled sensitivities, specificities, and diagnostic odds ratios (DOR) were calculated, and hierarchical summary operating curves were constructed.

RESULTS

Twenty-five studies (49 datasets), encompassing 3102 patients were included. Per-patient pooled sensitivities of CT, MRI, PET/CT, BS and SPECT were 70%, 93%, 82%, 75%, and 84%, respectively. Pooled specificities were 74%, 85%, 75%, 92%, and 81%, respectively. Per-lesion pooled sensitivities of CT, MRI, PET/CT, BS and SPECT were 76%, 91%, 92%, 77%, and 92%, respectively. Pooled specificities were 91%, 94%, 85%, 52%, and 86%, respectively. MRI had the highest DOR in per patient and lesion analyses.

CONCLUSION

MRI had highest diagnostic accuracy for spinal metastases detection on patient and lesion level, suggesting a broader use in addition to the routine staging CT, at least in patients at high risk and where the detection of a spinal metastasis could alter therapy decisions. Herein, results should be considered with the limitations of each modality.

Incidence, epidemiology, radiology, and classification of metastatic spine tumors: WFNS Spine Committee recommendations

Spinal metastasis (SMs) are the most encountered tumors of the spine. Their occurrence is expected roughly around one to two years after primary tumor diagnosis. Since the advent of Magnetic Resonance Imaging (MRI), this technology has been considered the gold standard for SMs diagnosis and characterization due to its precise ability to comprehend the rate of soft tissue compression/invasion (dural sac/nervous tissue), which is one of the main drivers of management strategies. Computed Tomography (CT) remains unbeatable when a detailed bony anatomy and instability assessment is searched. Nuclear medicine technologies may have a role in diagnosis when standard MR or CT study findings are inconclusive or when the extent of the systemic metastatic disease is studied. The main objective of this study is to offer an update on the epidemiology and radiology of spinal metastasis (SMs), endorsed by the WFNS Spine Committee. A systematic review of the literature of the last ten years gave 1531 results with "spine/spinal metastatic tumors/metastasis AND radiology OR imaging OR classification" as search strings in all fields, of which 56 papers were fully analyzed. The results were discussed and voted on in two consensus meetings of the WFNS (World Federation of Neurosurgical Societies) Spine Committee, reaching a positive or negative consensus using the Delphi method. The committee stated nine recommendations on two main topics: (1) Incidence and epidemiology of SMs; (2) Radiology and classifications of SMs.

Analysis of discordant PET and CT findings in 18F-FDG PET-CT scans in the management of oncology patients

BACKGROUND

Discordant findings are often noted between PET-CT and CT images of 18F-FDG PET-CT scans and cause ambiguity in image interpretation.This study aimed at determining the significance of these findings in the management of oncology patients.

CONTEXT

Discordant findings are often noted between PET-CT and CT images of 18F-FDG PET-CT scans and cause ambiguity in image interpretation.

AIM

This study aimed at determining the significance of these findings in the management of oncology patients.

METHODS

This was an observational, descriptive study. Hence, retrospective analysis of all discordant findings in oncology patients undergoing a PETCT imaging between Jan 2013 and Jan 2016 was done. Those patients who had a follow-up period of minimum 1 year in either of the following forms - repeat PETCT imaging, other radiological imaging, clinical, or histopathological evidence were included. From all the discordant lesions, the sensitivity, specificity, positive predictive, negative predictive value, and accuracy of both PET-CT and CT modalities were determined.

RESULTS

Of 348 discordant lesions, 16.7% was noted in soft tissues, 25% in viscera, 28.7% in lungs, 14.1% in lymph nodes, and 15.5% in bones. At the end of follow-up, 15.2% lesions were PET true positive, 57.5% PET true negative, 10.1% CT true positive lesions, 13.8% CT true negative, and 3.4% were inconclusive.

CONCLUSION

18F-FDG PET-CT is superior to CT imaging and should be considered as the first-line imaging modality in oncology patients.

MRI-based radiomics nomogram for differentiation of solitary metastasis and solitary primary tumor in the spine

BACKGROUND

Differentiating between solitary spinal metastasis (SSM) and solitary primary spinal tumor (SPST) is essential for treatment decisions and prognosis. The aim of this study was to develop and validate an MRI-based radiomics nomogram for discriminating SSM from SPST.

METHODS

One hundred and thirty-five patients with solitary spinal tumors were retrospectively studied and the data set was divided into two groups: a training set (n = 98) and a validation set (n = 37). Demographics and MRI characteristic features were evaluated to build a clinical factors model. Radiomics features were extracted from sagittal T1-weighted and fat-saturated T2-weighted images, and a radiomics signature model was constructed. A radiomics nomogram was established by combining radiomics features and significant clinical factors. The diagnostic performance of the three models was evaluated using receiver operator characteristic (ROC) curves on the training and validation sets. The Hosmer-Lemeshow test was performed to assess the calibration capability of radiomics nomogram, and we used decision curve analysis (DCA) to estimate the clinical usefulness.

RESULTS

The age, signal, and boundaries were used to construct the clinical factors model. Twenty-six features from MR images were used to build the radiomics signature. The radiomics nomogram achieved good performance for differentiating SSM from SPST with an area under the curve (AUC) of 0.980 in the training set and an AUC of 0.924 in the validation set. The Hosmer-Lemeshow test and decision curve analysis demonstrated the radiomics nomogram outperformed the clinical factors model.

CONCLUSIONS

A radiomics nomogram as a noninvasive diagnostic method, which combines radiomics features and clinical factors, is helpful in distinguishing between SSM and SPST.

Diagnostic Technology for Spine Pathology

Diagnostic techniques for spinal pathologies have been developed in accordance with advances in technology. Accurate diagnosis of spinal pathology is essential for appropriate management of spinal diseases. Since the development of X-rays in 1895 and computed tomography (CT) in 1967, several diagnostic imaging modalities have been utilized for detecting spinal pathologies, including radiography, CT, magnetic resonance imaging, and radionuclide imaging. In addition to diagnostic imaging technologies, electrodiagnostic tests, including electromyography and nerve conduction studies, play a significant role as diagnostic tools, as spinal diseases are mostly profoundly associated with pathologies of the neural structures, such as the spinal cord and nerve root, and extent of injury at the structure cannot be adequately detected by conventional imaging techniques. In patient-specific treatment strategies, usage of diagnostic modalities is of great importance; thus, we should be aware of the basic details and approaches of the different diagnostic modalities. In this review, the authors discuss the details of the technologies that aid in the diagnosis of spinal pathologies.

[18F]FDG-PET Evaluation of Spinal Pathology in Patients in Oncology: Pearls and Pitfalls for the Neuroradiologist

[¹⁸F]FDG-PET is a widely used technique for specific evaluation of disease and treatment response in oncology. However, the principles behind [¹⁸F]FDG-PET imaging allow a wide-ranging array of benign and malignant pathologies to be identified on both initial and routine surveillance imaging. This is important for clinicians and radiologists, alike, in that effective and accurate evaluation of malignancy and metastatic disease, specifically involving the spine and central nervous system, is crucial. In this article, we review the normal and posttherapy appearance of the spine on [¹⁸F]FDG-PET, the various types and patterns of metastatic disease that involve the spine and spinal cord, and, finally, important spinal pathologies that may mimic malignancy on [¹⁸F]FDG-PET.

Clinical Usefulness of [18F]-Fluoro-2-Deoxy-d-Glucose-Positron Emission Tomography/Computed Tomography for Distinguishing Between Autoimmune Pancreatitis and Pancreatic Cancer

OBJECTIVES

We investigated the [18F]-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) findings of pancreatic and extrapancreatic lesions in patients with autoimmune pancreatitis (AIP) and pancreatic cancer (PC) and evaluated the usefulness of 18F-FDG-PET/CT for differentiating between AIP and PC.

METHODS

Eighty-five patients, 19 with AIP and 66 with PC, who underwent 18F-FDG-PET/CT were studied retrospectively. We evaluated the maximum standardized uptake value (SUVmax), patterns and distributions of FDG activity in pancreatic lesions, as well as FDG uptake in extrapancreatic lesions.

RESULTS

The levels of SUVmax of pancreatic lesions in PC patients were significantly higher than those in AIP patients (P < 0.05). Focal/segmental distribution of FDG activity was found in 61.1% of the AIP patients and 98.4% of the PC patients. Heterogeneous FDG activity patterns were found in 61.1% of the AIP patients and 18.7% of the PC patients. Activities of FDG in pancreatic lesions were significantly different between AIP and PC. Extrapancreatic activities of salivary glands, extraperitoneal lymph nodes, prostate, retroperitoneum, and kidneys in the AIP patients were significantly higher than those in the PC patients (P < 0.05). Multivariate analysis revealed that SUVmax (>7.08) and focal/segmental FDG distribution were independent predictors of PC (P < 0.05).

CONCLUSIONS

The 18F-FDG-PET/CT findings are useful for differentiating between AIP and PC.

Differentiation Between Osteoporotic And Neoplastic Vertebral Fractures: State Of The Art And Future Perspectives

Vertebral fractures are a common condition, occurring in the context of osteoporosis and malignancy. These entities affect a group of patients in the same age range; clinical features may be indistinct and symptoms non-existing, and thus present challenges to diagnosis. In this article, we review the use and accuracy of different imaging modalities available to characterize vertebral fracture etiology, from well-established classical techniques, to the role of new and advanced imaging techniques, and the prospective use of artificial intelligence. We also address the role of imaging on treatment. In the context of osteoporosis, the importance of opportunistic diagnosis is highlighted. In the near future, the use of automated computer-aided diagnostic algorithms applied to different imaging techniques may be really useful to aid on diagnosis.

Texture Analysis of 18F-FDG PET/CT for Differential Diagnosis Spinal Metastases

Purpose: To evaluate the value of texture analysis for the differential diagnosis of spinal metastases and to improve the diagnostic performance of 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for spinal metastases.

Methods: This retrospective analysis of patients who underwent PET/CT between December 2015 and January 2020 at Shanghai Tenth People's Hospital due to high FDG uptake lesions in the spine included 45 cases of spinal metastases and 44 cases of benign high FDG uptake lesions in the spine. The patients were randomly divided into a training group of 65 and a test group of 24. Seventy-two PET texture features were extracted from each lesion, and the Mann-Whitney U-test was used to screen the training set for texture parameters that differed between the two groups in the presence or absence of spinal metastases. Then, the diagnostic performance of the texture parameters was screened out by receiver operating characteristic (ROC) curve analysis. Texture parameters with higher area under the curve (AUC) values than maximum standardized uptake values (SUVmax) were selected to construct classification models using logistic regression, support vector machines, and decision trees. The probability output of the model with high classification accuracy in the training set was used to compare the diagnostic performance of the classification model and SUVmax using the ROC curve. For all patients with spinal metastases, survival analysis was performed using the Kaplan-Meier method and Cox regression.

Results: There were 51 texture parameters that differed meaningfully between benign and malignant lesions, of which four had higher AUC than SUVmax. The texture parameters were input to build a classification model using logistic regression, support vector machine, and decision tree. The accuracy of classification was 87.5, 83.34, and 75%, respectively. The accuracy of the manual diagnosis was 84.27%. Single-factor survival analysis using the Kaplan-Meier method showed that intensity was correlated with patient survival.

Conclusion: Partial texture features showed higher diagnostic value for spinal metastases than SUVmax. The machine learning part of the model combined with the texture parameters was more accurate than manual diagnosis. Therefore, texture analysis may be useful to assist in the diagnosis of spinal metastases.

Standardized Uptake Value from Semiquantitative Bone Single-Photon Emission Computed Tomography/Computed Tomography in Normal Thoracic and Lumbar Vertebrae of Breast Cancer Patients

STUDY DESIGN

Retrospective study.

PURPOSE

This study aims to semiquantitatively evaluate the standardized uptake value (SUV) of 99mTc-methylene diphosphonate (MDP) radionuclide tracer in the normal vertebrae of breast cancer patients using an integrated single-photon emission computed tomography (SPECT)/computed tomography (CT) scanner.

OVERVIEW OF LITERATURE

Molecular imaging techniques using gamma cameras and stand-alone SPECT have traditionally been utilized to evaluate metastatic bone diseases. However, these methods lack quantitative analysis capabilities, impeding accurate uptake characterization.

METHODS

A total of 30 randomly selected female breast cancer patients were enrolled in this study. The SUV mean (SUVmean) and SUV maximum (SUVmax) values for 286 normal vertebrae at the thoracic and lumbar levels were calculated based on the patients' body weight (BW), body surface area (BSA), and lean body mass (LBM). Additionally, 106 degenerative joint disease (DJD) lesions of the spine were also characterized, and both their BW SUVmean and SUVmax values were obtained. A receiver operating characteristic (ROC) curve analysis was then performed to determine the cutoff value of SUV for differentiating DJD from normal vertebrae.

RESULTS

The mean±standard deviations for the SUVmean and SUVmax in the normal vertebrae displayed a relatively wide variability: 3.92±0.27 and 6.51±0.72 for BW, 1.05±0.07 and 1.75±0.17 for BSA, and 2.70±0.19 and 4.50±0.44 for LBM, respectively. Generally, the SUVmean had a lower coefficient of variation than the SUVmax. For DJD, the mean±standard deviation for the BW SUVmean and SUVmax was 5.26±3.24 and 7.50±4.34, respectively. Based on the ROC curve, no optimal cutoff value was found to differentiate DJD from normal vertebrae.

CONCLUSIONS

In this study, the SUV of 99mTc-MDP was successfully determined using SPECT/CT. This research provides an approach that could potentially aid in the clinical quantification of radionuclide uptake in normal vertebrae for the management of breast cancer patients.

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.

What is the Diagnostic Performance of 18F-FDG-PET/MRI in the Detection of Bone Metastasis in Patients with Breast Cancer?

Objective

To evaluate the diagnostic performance of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/magnetic resonance imaging (MRI) in the detection of bone metastasis in patients with breast cancer.

Materials and methods

From August 2018 to January 2019, a total of 23 patients with pathologically confirmed invasive breast cancer underwent whole-body hybrid 18F-FDG -PET/MRI for initial staging and follow-up of their malignancies. The number of the bone metastasis was recorded for each patient. The total 18F-FDG-PET/MRI protocol was compared with PET only and the contrast enhanced fused (CE) component for the detection of bone metastasis.

Results

Eight (26%) of 23 patients had bone metastasis. Bone metastases were dominantly localized in the spine (63%) and pelvis (25%). In terms of the total number of detected bone metastasis, there was a statistically significant difference between 18F-FDG-PET/MRI (mean 3.57; median 0; range, 0-2) and PET only component (mean 2.87; median 0; range, 0-1) (p=0.026), but no statistically significant difference was detected between 18F-FDG-PET/MRI and whole-body CE MRI (mean 3.43; median 0; range 0-2) (p=0.083).

Conclusion

Whole-body hybrid 18F-FDG-PET/MRI is superior to PET component only, but no statistically significant difference between hybrid 18F-FDG-PET/MRI and whole-body CE MRI is found for the detection of bone metastasis in patients with breast cancer.

Prognostic Value of Tumor Heterogeneity on 18F-FDG PET/CT in HR+HER2- Metastatic Breast Cancer Patients receiving 500 mg Fulvestrant: a retrospective study

Heterogeneity has been demonstrated to be a predictor of treatment failure and drug resistance. Our study aimed to investigate imaging parameters, including tumor heterogeneity, as prognostic factors of response to 500 mg fulvestrant using 18F-FDG PET/CT. Twenty-seven estrogen receptor (HR)-positive/HER2-negative metastatic breast cancer patients who received 500 mg fulvestrant and underwent 18F-FDG PET/CT before treatment were retrospectively included. In PET/CT scans, conventional parameters (maximum and mean standardized uptake value, metabolic tumor volume [MTV], total lesion glycolysis [TLG]) and heterogeneity parameters (intra-tumor heterogeneity index [HI] and inter-tumor heterogeneity coefficient of variation [COV]) were analyzed. Progression-free survival (PFS) was mainly assessed for efficacy. The survival analyses were performed using the Kaplan-Meier method. Univariate and multivariate analysis were performed using the Cox proportional hazard model. Univariate analysis indicated that a high SUVmax and a high tumor HI at baseline were associated with longer PFS of fulvestrant (P = 0.036 and P = 0.033, respectively). Liver metastasis, SUVmax and HI were statistically significant in multivariate analysis (P values of 0.017, 0.025 and 0.043, respectively). 18F-FDG based intra-tumor heterogeneity appears to be a potential predicator of efficacy of fulvestrant among HR+HER2- metastatic breast cancer patients.

Diagnosis of non-osseous spinal metastatic disease: the role of PET/CT and PET/MRI

The spine is the third most common site for distant metastasis in cancer patients with approximately 70% of patients with metastatic cancer having spinal involvement. Positron emission tomography (PET), combined with computed tomography (CT) or magnetic resonance imaging (MRI), has been deeply integrated in modern clinical oncology as a pivotal component of the diagnostic work-up of patients with cancer. PET is able to diagnose several neoplastic processes before any detectable morphological changes can be identified by anatomic imaging modalities alone. In this review, we discuss the role of PET/CT and PET/MRI in the diagnostic management of non-osseous metastatic disease of the spinal canal. While sometimes subtle, recognizing such disease on FDG PET/CT and PET/MRI imaging done routinely in cancer patients can guide treatment strategies to potentially prevent irreversible neurological damage.

Diagnostic Value of Technetium-99m Bone Scintigraphy in the Detection of Cervical Spine Metastases in Oncological Patients

MINI: Bone scan remains the modality of choice for the screening of bone metastases. This study demonstrated the diagnostic value of bone scan in detecting bone metastases limited to the cervical spine in oncological patients remains uncertain due to the moderately high false-negative diagnostic rate.

STUDY DESIGN

A retrospective cohort, radiographic study.

OBJECTIVE

To assess the diagnostic accuracy of bone scintigraphy (BS) for the detection of cervical spine metastases in oncological patients.

SUMMARY OF BACKGROUND DATA

BS remains the modality of choice for the screening of bone metastases, because of its feasibility in whole-body scanning and its widespread availability at low cost. Current practice guidelines for patients with malignant diseases recommend BS imaging as the primary screening method for detecting both axial and appendicular skeletal metastases.

METHODS

Of 481 patients, 242 were diagnosed with cervical spinal metastases from a primary cancer. The BS findings of these patients, evaluated by nuclear medicine physicians, were assessed with respect to their usefulness for detecting cervical spine metastases. Magnetic resonance imaging findings, evaluated by radiologists, were used as the reference standards. The diagnostic value of BS was compared between subgroups according to the order in which the diagnostic procedures (magnetic resonance imaging and BS) were completed, the presence of pathological fractures, the location of the primary malignancy, and the number of cervical metastases.

RESULTS

The sensitivity of BS in the detection of cervical spine metastases was 59.1%, with a 40.9% rate of false-negative diagnoses; the specificity was 94.6%, with a 5.4% rate of false-positive diagnoses. The sensitivity tended to be higher in the presence of pathological fractures (72.1% in cases with a fracture vs. 3% in cases without a fracture) and a greater number of lesions (r = 0.921). Neither the order in which the diagnostic examinations were performed nor the location of the primary cancer, except for those in the stomach and liver, appeared to affect the diagnostic accuracy of BS.

CONCLUSION

Considering the moderately high false-negative diagnostic rate obtained in the present study, BS alone cannot accurately diagnose metastases in the cervical spine in oncological patients.

LEVEL OF EVIDENCE

3.

Spinal Metastatic Disease: A Review of the Role of the Multidisciplinary Team

Historically, a simple approach centered on palliation was applicable to the majority of patients with metastatic spinal disease. With advances in diagnosis and treatment, a more complicated algorithm has devolved requiring a multidisciplinary approach with institutional commitment and support. We performed a database review including pertinent articles exploring the multidisciplinary management of spinal metastatic disease. The wide variation in clinical presentation and tumor response to treatment necessitates a multidisciplinary approach that integrates the diagnosis and treatment of the cancer, symptom management, and rehabilitation for optimal care of patients with spinal metastases. Advances in the field of radiology have led to earlier and more focused diagnosis of spinal metastasis and acts to guide therapy. Advances in surgical techniques, neurophysiologic monitoring, and anesthetic expertise have allowed surgeons to perform more extensive procedures leading to improved outcomes and reduced morbidity. Radiation oncology input that is essential as external beam radiation therapy can provide significant pain relief. Non-operative measures may include bisphosphonate infusions, management of complications (e.g. hypercalcemia of malignancy), monoclonal antibody infusions, and chemotherapy if indicated in the treatment of the primary malignancy. Input from psychology services is necessary to address the biopsychosocial ramifications of spinal metastasis. Allied health professionals in the form of physiotherapists, social workers, and dieticians also contribute in maximizing patients' quality of life and well-being.

Clinical study of 99mTc-3P-RGD2 peptide imaging in osteolytic bone metastasis

Objective

To investigate the value of integrin α_vβ₃ targeted imaging with ^99mTc-HYNIC-PEG₄-E[PEG₄-c(RGDfk)]₂ (^99mTc-3P-RGD₂) as a radiotracer in dectecting osteolytic bone metastases.

Methods

This is a retrospective study involving a cohort of 69 consecutive patients including 59 with lung cancer and 10 with other cancers. Patients were required to receive whole body scan (WBS) and regional SPECT/CT imaging with ^99mTc-3P-RGD₂ (RGD imaging) and ^99mTc-MDP (MDP imaging) as a radiotracer successively within days. Final diagnosis was based on comprehensive assessment of all available data including case history, CT, MRI, SPECT/CT, PET/CT, histopathology and 6-12 months follow-up. Visual observation and semiquantitative analysis (T/N: tracer uptake ratio of osteolytic metastases to normal bone) of ^99mTc-3P-RGD₂ or ^99mTc-MDP imaging were performed and their detective values for osteolytic metastases were compared.

Results

A total of 131 osteolytic metastatic lesions were retrospectively studied. Osteolytic metastases mainly presented as “hot region”, occasionally as “cool or normal region” on RGD imaging. The detection sensitivity of RGD WBS for osteolytic metastases was significantly higher than that of ^99mTc-MDP WBS (80.9% vs. 46.6%, p<0.01). The sensitivity increased to 96.2% (126/131) when combining with SPECT/CT. ^99mTc-3P-RGD₂ imaging also promoted the detection of unknown primary tumor, lymph node metastases and offered information for clinical staging. T/N of ^99mTc-3P-RGD₂ in lung adenocarcinoma osteolytic metastases showed no statistical difference compared with that in squamous-cell carcinoma (6.84±3.46 vs. 7.33±3.22, t = 0.39, p = 0.71). Whereas, it was higher in osteolytic metastases from lung cancer than that from thyroid cancer (7.05±3.01 vs. 4.11±2.67, p = 0.03).

Conclusion

^99mTc-3P-RGD₂ peptide imaging showed great potential for detection of osteolytic bone metastasis due to high expression level of integrin αvβ3 on osteoclast and most tumor cells.

Skeletal Metastasis as Detected by 18F-FDG PET with Negative CT of the PET/CT: Frequency and Impact on Cancer Staging and/or Management

OBJECTIVES

The aim of our study is to assess the frequency of detection of PET-positive computed tomography (CT)-negative skeletal metastases (SM) and determine the impact of such detection on staging and/or management in patients who had FDG PET/CT as part of the cancer work-up.

METHODS

We retrospectively reviewed 2000 18F-FDG PET/CT scans of known cancer patients. A log was kept to record cases of suspected SM with or without bone changes from the low-dose non-contrast CT. The presence or absence of SM was evaluated based on available pathological and clinical data. The impact of detection of such lesions on cancer staging and/or management was evaluated by a board certified oncologist.

RESULTS

Of the 2000 cases, 18F-FDG PET/CT suggested SM in 146/2000 (7.3%). Of those 146 cases, 105 (72%) were positive on both PET and CT. The remaining 41 (28%) had PET-positive CT-negative bone lesions. SM was confirmed in 36/41 (88%) PET-positive/CT-negative cases. This was based on biopsy, imaging, or clinical follow-up. The detection of PET-positive CT-negative SM did not change staging or management in 7/36 (19.4%). However, staging and/or management was affected in 29/36 (80.6%).

CONCLUSION

SM is not uncommon in 18F-FDG PET/CT, as it accounts for 146/2000 (7.3%) of cases. PET demonstrated FDG-avid SM without a CT abnormality in at least 36/146 (25%). Patients staging and/or management changed in 29/36 (80.5%). We concluded that 18F-FDG PET is sensitive in the detection of SM with significant impact on staging and/or management.

Mandibular metastasis of cholangiocarcinoma: A case report

Tumors metastasizing from distant regions to the oral and maxillofacial region are uncommon, comprising only 1%-2% of all malignancies. Cholangiocarcinoma is a malignancy that arises from cholangiocytes, which are epithelial cells that line the bile ducts. These cancers are difficult to diagnose and have a poor prognosis. In this paper, we report a rare case of mandibular metastasis of cholangiocarcinoma diagnosed at the primary site and discuss the radiographic findings observed in this case.

A comparative study of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and (99m)Tc-MDP whole-body bone scanning for imaging osteolytic bone metastases

Background

The objective of this study was to evaluate the feasibility and diagnostic value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and ^99mTc-methylenediphosphonate (MDP) whole-body bone scanning (BS) for the detection of osteolytic bone metastases.

Methods

Thirty-four patients with pathologically confirmed malignancies and suspected osteolytic bone metastases underwent ¹⁸F-FDG PET/CT and ^99mTc-MDP whole-body BS within 30 days. The sensitivity, specificity, and accuracy with respect to the diagnosis of osteolytic bone metastases and bone lesions were compared between the two imaging methods.

Results

The sensitivity, specificity, and accuracy of ¹⁸F-FDG PET/CT for the diagnosis of osteolytic bone metastases were 94.3% (95% confidence interval [CI], 91.6–96.2%), 83.3% (95% CI, 43.6–96.9%), and 94.2% (95% CI, 91.5–96.1%), respectively. It was found that ^99mTc-MDP whole-body BS could discriminate between patients with 50.2% (95% CI, 45.4–55.1%) sensitivity, 50.0% (95% CI, 18.8–81.2%) specificity, and 50.2% (95% CI, 45.5–55.1%) accuracy. ¹⁸F-FDG PET/CT achieved higher sensitivity, specificity, and accuracy in detecting osteolytic bone metastases than 99mTc-MDP whole-body BS (p<0.001).

Conclusions

F-FDG PET/CT has a higher diagnostic value than ^99mTc-MDP whole-body BS in the detection of osteolytic bone metastases, especially in the vertebra.

Molecular imaging in oncology: (18)F-sodium fluoride PET imaging of osseous metastatic disease

OBJECTIVE

This literature review details the history, pharmacokinetics, and utility of (18)F-sodium fluoride (Na(18)F) PET/CT in detecting osseous metastases compared with the current standard of care, technetium-99m methylene diphosphonate ((99m)Tc-MDP) bone scintigraphy. Additional discussion highlights solutions to impediments for broader implementation of this modality and insight into the complementary roles of (18)F-FDG PET/CT and Na(18)F PET/CT in oncology imaging, including preliminary data for combined Na(18)F and FDG PET/CT.

CONCLUSION

Na(18)F PET/CT is the most comprehensive imaging modality for the evaluation of osseous metastatic disease. Although further data acquisition is necessary to expand cost-benefit analyses of this imaging agent, emerging data reinforce its diagnostic advantage, suggest methods to mitigate impediments to broader utilization of Na(18)F PET/CT, and introduce a potentially viable technique for single-session combined Na(18)F and FDG PET/CT staging of soft-tissue and osseous disease.