The role of 18F-fluoride PET-CT in the detection of bone metastases in patients with breast, lung and prostate carcinoma: a comparison with FDG PET/CT and 99mTc-MDP bone scan

No prognostic impact of staging bone scan in patients with stage IA non-small cell lung cancer

OBJECTIVE

To investigate the survival benefit of preoperative bone scan in asymptomatic patients with early-stage non-small cell lung cancer (NSCLC).

METHODS

This retrospective study included patients with radical resection for stage T1N0M0 NSCLC between March 2013 and December 2018. During postoperative follow-up, we monitored patient survival and the development of bone metastasis. We compared overall survival, bone metastasis-free survival, and recurrence-free survival in patients with or without preoperative bone scan. Propensity score matching and inverse probability of treatment weighting were used to minimize election bias.

RESULTS

A total of 868 patients (58.19 ± 9.69 years; 415 men) were included in the study. Of 87.7% (761 of 868) underwent preoperative bone scan. In the multivariable analyses, bone scan did not improve overall survival (hazard ratio [HR] 1.49; 95% confidence intervals [CI] 0.91-2.42; p = 0.113), bone metastasis-free survival (HR 1.18; 95% CI 0.73-1.90; p = 0.551), and recurrence-free survival (HR 0.89; 95% CI 0.58-1.39; p = 0.618). Similar results were obtained after propensity score matching (overall survival [HR 1.28; 95% CI 0.74-2.23; p = 0.379], bone metastasis-free survival [HR 1.00; 95% CI 0.58-1.72; p = 0.997], and recurrence-free survival [HR 0.76; 95% CI 0.46-1.24; p = 0.270]) and inverse probability of treatment weighting.

CONCLUSION

There were no significant differences in overall survival, bone metastasis-free survival, and recurrence-free survival between asymptomatic patients with clinical stage IA NSCLC with or without preoperative bone scan.

Bone Metastases

ABSTRACT

Bone metastases occur frequently in common malignancies such as breast and prostate cancer. They are responsible for considerable morbidity and skeletal-related events. Fortunately, there are now several systemic, focal, and targeted therapies that can improve quality and length of life, including radionuclide therapies. It is therefore important that bone metastases can be detected as early as possible and that treatment can be accurately and sensitively monitored. Several bone-specific and tumor-specific single-photon emission computed tomography and positron emission tomography molecular imaging agents are available, for detection and monitoring response to systemic therapeutics, as well as theranostic agents to confirm target expression and predict response to radionuclide therapies.

Bisphosphonates as Radiopharmaceuticals: Spotlight on the Development and Clinical Use of DOTAZOL in Diagnostics and Palliative Radionuclide Therapy

Bisphosphonates are therapeutic agents that have been used for almost five decades in the treatment of various bone diseases, such as osteoporosis, Paget disease and prevention of osseous complications in cancer patients. In nuclear medicine, simple bisphosphonates such as 99mTc-radiolabelled oxidronate and medronate remain first-line bone scintigraphic imaging agents for both oncology and non-oncology indications. In line with the growing interest in theranostic molecules, bifunctional bisphosphonates bearing a chelating moiety capable of complexing a variety of radiometals were designed. Among them, DOTA-conjugated zoledronate (DOTAZOL) emerged as an ideal derivative for both PET imaging (when radiolabeled with 68Ga) and management of bone metastases from various types of cancer (when radiolabeled with 177Lu). In this context, this report provides an overview of the main medicinal chemistry aspects concerning bisphosphonates, discussing their roles in molecular oncology imaging and targeted radionuclide therapy with a particular focus on bifunctional bisphosphonates. Particular attention is also paid to the development of DOTAZOL, with emphasis on the radiochemistry and quality control aspects of its preparation, before outlining the preclinical and clinical data obtained so far with this radiopharmaceutical candidate.

Gradual normalization of superscan in prostate cancer: A case report and literature review

This report presents the imaging findings in a patient with advanced prostate cancer and bone metastases. A superscan pattern on the initial whole-body bone scan suggested extensive disease. The patient responded well to definitive treatment, exhibiting clinical improvement based on decreased PSA levels and CT findings in 6-month follow-up. However, serial follow-up bone scans showed normalization in about 18 months. This paper aims to discuss the limitations of bone scintigraphy in evaluating treatment responses in patients with prostate cancer.

Meta-analysis of 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CT, and 68Ga-PSMA PET/CT in diagnostic efficacy of prostate Cancer

OBJECTIVE

To compare 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CT and 68Ga-PSMA PET/CT in the diagnostic value of prostate cancer.

METHOD

The Chinese and foreign databases, such as Pubmed, Cochrane Library, Embase, CNKI, VIP, Wanfang, etc., were systematically searched within the period from the establishment of the database to June 1, 2022. Clinical studies related to the diagnosis of prostate cancer by methods such as 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CTCT, 68Ga-PSMA PET/CT, were researched. Two (2) investigators independently screened literatures, extracted data, and assessed the risk of bias when these data were included in the studies with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Review Manager5.4, Stata 14.0, and Meta-disc 1.4 software were used for meta-analysis to compare the efficacy of different methods in the diagnose of prostate cancer.

RESULTS

Twenty-seven (27) studies, including 2891 subjects were included in our study. Meta-analysis results showed that the pooled sensitivities of 18 F-PSMA-1007 PET/CT, 18 F-FDG PET/CT, and 68Ga-PSMA PET/CT were 0.912 (95%CI: 0.883-0.936), 0.748 (95%CI: 0.698-0.795), and 0.916 (95%CI: 0.896-0.934), respectively; the pooled specification were 0.878 (0.844-0.907), 0.639 (95%CI: 0.589-0.687), and 0.734 (95%CI: 0.685-0.779), respectively; the positive likelihood ratios were 6.335 (95%CI: 4.288-9.357), 2.282 (95%CI: 1.497-3.477), and 3.593 (95%CI: 2.986-4.323), respectively; the negative likelihood ratios were 0.878 (95%CI: 0.844-0.907), 0.374 (95%CI: 0.280-0.499), and 0.110 (95%CI: 0.083-0.144), respectively; the diagnostic odds ratios were 65.125 (95%CI: 34.059-124.53), 7.094 (95%CI: 4.091-12.301), and 29.722 (95%CI: 20.141-43.863), respectively; the positive posterior probability was 64%, 38%, and 62%, respectively; the area under the SPOC curve was 0.95 (95%CI: 0.93-0.97), 0.81 (95%CI: 0.78-0.84), and 0.96 (95%CI: 0.92-0.98), respectively. The funnel plots indicated that there was no significant publication bias in the included literatures.

CONCLUSION

The current evidences showed that 18 F-PSMA-1007 PET/CT and 68Ga-PSMA PET/CT had higher diagnostic efficacy of prostate cancer compared with 18 F-FDG PET/CT, among which 68Ga-PSMA PET/CT was slightly higher in the sensitivity of the diagnosis of prostate cancer, while 18 F-PSMA-1007 PET/CT may have higher efficacy in specificity and confirmed positive rate. Due to the limitations of the quality of the included samples and literatures, the above conclusions should be further validated by expanding the sample size and improving the quality.

Whole body imaging in musculoskeletal oncology: when, why, and how

The use of whole-body imaging has become increasingly popular in oncology due to the possibility of evaluating total tumor burden with a single imaging study. This is particularly helpful in cases of widespread disease where dedicated regional imaging would make the evaluation more expensive, time consuming, and prone to more risks. Different techniques can be used, including whole-body MRI, whole-body CT, and PET-CT. Common indications include surveillance of cancer predisposing syndromes, evaluation of osseous metastases and clonal plasma cell disorders such as multiple myeloma, and evaluation of soft tissue lesions, including peripheral nerve sheath tumors. This review focuses on advanced whole-body imaging techniques and their main uses in musculoskeletal oncology.

Intra-individual comparison of 18F-sodium fluoride PET-CT and 99mTc bone scintigraphy with SPECT in patients with prostate cancer or breast cancer at high risk for skeletal metastases (MITNEC-A1): a multicentre, phase 3 trial

BACKGROUND

Detection of skeletal metastases in patients with prostate cancer or breast cancer remains a major clinical challenge. We aimed to compare the diagnostic performance of ^99mTc-methylene diphosphonate (^99mTc-MDP) single-photon emission CT (SPECT) and ¹⁸F-sodium fluoride (¹⁸F-NaF) PET-CT for the detection of osseous metastases in patients with high-risk prostate or breast cancer.

METHODS

MITNEC-A1 was a prospective, multicentre, single-cohort, phase 3 trial conducted in ten hospitals across Canada. Patients aged 18 years or older with breast or prostate cancer with a WHO performance status of 0-2 and with high risk or clinical suspicion for bone metastasis, but without previously documented bone involvement, were eligible. ¹⁸F-NaF PET-CT and ^99mTc-MDP SPECT were done within 14 days of each other for each participant. Two independent reviewers interpreted each modality without knowledge of other imaging findings. The primary endpoint was the overall accuracy of ^99mTc-MDP SPECT and ¹⁸F-NaF PET-CT scans for the detection of bone metastases in the per-protocol population. A combination of histopathological, clinical, and imaging follow-up for up to 24 months was used as the reference standard to assess the imaging results. Safety was assessed in all enrolled participants. This study is registered with ClinicalTrials.gov, NCT01930812, and is complete.

FINDINGS

Between July 11, 2014, and March 3, 2017, 290 patients were screened, 288 of whom were enrolled (64 participants with breast cancer and 224 with prostate cancer). 261 participants underwent both ¹⁸F-NaF PET-CT and ^99mTc-MDP SPECT and completed the required follow-up for statistical analysis. Median follow-up was 735 days (IQR 727-750). Based on the reference methods used, 109 (42%) of 261 patients had bone metastases. In the patient-based analysis, ¹⁸F-NaF PET-CT was more accurate than ^99mTc-MDP SPECT (84·3% [95% CI 79·9-88·7] vs 77·4% [72·3-82·5], difference 6·9% [95% CI 1·3-12·5]; p=0·016). No adverse events were reported for the 288 patients recruited.

INTERPRETATION

¹⁸F-NaF has the potential to displace ^99mTc-MDP as the bone imaging radiopharmaceutical of choice in patients with high-risk prostate or breast cancer.

FUNDING

Canadian Institutes of Health Research.

Imaging of Bone Metastases in Breast Cancer

Bone metastases are a common site of spread in advanced breast cancer and responsible for morbidity and high health care costs. Imaging contributes to staging and response assessment of the skeleton and has been instrumental in guiding patient management for several decades. Historically this has been with radiographs, computed tomography and bone scans. More recently, molecular and hybrid imaging methods have undergone significant development, including the addition of single photon emission computed tomography/computed tomography to the bone scan, positron emission tomography, with bone-specific and tumor-specific tracers, and magnetic resonance imaging with complementary functional diffusion-weighted imaging. These have allowed different aspects of the abnormal biology associated with bone metastases to be explored. There is ability to interrogate the bone microenvironment with bone-specific tracers and cancer cell characteristics with tumor-specific methods that complement morphological appearances on computed tomography or magnetic resonance imaging. Alongside the advent of novel, more effective and nuanced therapies for bone metastases in breast cancer, there is accumulating evidence that the developments in imaging allow more sensitive and specific detection of bone metastases as well as more accurate and earlier assessment of treatment response leading to improvements in patient management.

Systematic review & meta-analysis of positron emission tomography/computed tomography and bone scan in the diagnosis of prostate lesions

Background

To date, the results of studies into the effectiveness of positron emission tomography (PET) combined with computed tomography (CT) and bone scan (BS) in the diagnosis of malignant prostate lesions have been inconsistent, and the advantages and disadvantages of the two methods cannot be accurately judged.

Methods

Articles were retrieved from the China National Knowledge Infrastructure (CNKI) database, Wan Fang Medical Network, PubMed, Excerpta Medica data BASE (EMBASE), Medline, and Cochrane database. The keywords used in the search were: ⁶⁸Ga-prostate specific membrane antibody (⁶⁸Ga-PSMA), PET/CT, prostate lesions, prostate adenocarcinoma, bone metastasis, and BS.

Results

Ultimately, 3 publications were selected for inclusion in the meta-analysis. A total of 215 patients were considered in the 3 articles that met the inclusion criteria. All of the included articles were small sample studies, with sample sizes ranging from 28 to 113 cases. In this study, from the 3 randomized controlled trials, only 2 (66.67%) randomized controls described the correct randomized allocation method, and only 1 (33.33%) described the hidden allocation scheme in detail. The highest sensitivity for ⁶⁸Ga-PSMA PET/CT was 0.96, with 95% CI: 0.87, 1.00, and the highest specificity was 1.00, with 95% CI: 0.96, 1.00. The highest sensitivity and specificity of BS were 0.92 with 95% CI: 0.81, 0.98 and 0.96 with 95% CI: 0.78, 1.00, respectively. The results of meta-analysis of ⁶⁸Ga-PSMA PET/CT diagnosis with confirmation by surgical and histopathological examination showed that the area under the summary receiver operating characteristics (SROC) curve (AUC) =0.826 and standard error (SE) (AUC) =0.0425. The results of meta-analysis of BS diagnosis with confirmation by surgical and histopathological examination showed that the area under the SROC curve (AUC) =0.714 and SE (AUC) =0.0034.

Discussion

The meta-analysis showed that ⁶⁸Ga-PSMA PET/CT has clear advantages over BS in the diagnosis of bone metastases of malignant prostate tumors, and could improve the diagnostic accuracy of bone metastases.

68Ga-P15-041, A Novel Bone Imaging Agent for Diagnosis of Bone Metastases

Objectives

⁶⁸Ga-P15-041 (⁶⁸Ga-HBED-CC-BP) is a novel bone-seeking PET radiotracer, which can be readily prepared by using a simple kit formulation and an in-house ⁶⁸Ga/⁶⁸Ge generator. The aim of this study is to assess the potential human application of ⁶⁸Ga-P15-041 for clinical PET/CT imaging and to compare its efficacy to detect bone metastases of different cancers with ⁹⁹mTc-MDP whole-body bone scintigraphy (WBBS).

Methods

Initial kinetic study using Patlak analysis and parametric maps were performed in five histopathologically proven cancer patients (three males, two females) using ⁶⁸Ga-P15-041 PET/CT scan only. Another group of 51 histopathologically proven cancer patients (22 males, 29 females) underwent both ⁹⁹mTc-MDP WBBS and ⁶⁸Ga-P15-041 PET/CT scans within a week, sequentially. Using either pathology examination or follow-up CT or MRI scans as the gold standard, the diagnostic efficacy and receiver operating characteristic curve (ROC) of the two methods in identifying bone metastases were compared (p <0.05, statistically significant).

Results

Fifty-one patients were imaged, and 174 bone metastatic sites were identified. ⁶⁸Ga-P15-041 PET/CT and ⁹⁹mTc-MDP WBBS detected 162 and 81 metastases, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ⁶⁸Ga-P15-041 PET/CT and ⁹⁹mTc-MDP WBBS were 93.1% vs 81.8%, 89.8% vs 90.7%, 77.5% vs 69.2%, 97.2% vs 93.4% and 90.7% vs 88.4%, respectively. Our results showed that the mean of SUVmax was significantly higher in metastases than that in benign lesions, 15.1 ± 6.9 vs. 5.6 ± 1.3 (P <0.001). Using SUVmax = 7.6 as the cut-off value by PET/CT, it was possible to predict the occurrence of metastases (AUC = 0.976; P <0.001; 95% CI: 0.946–0.999). However, it was impossible to distinguish osteoblastic bone metastases from osteolytic bone lesions. Parametric maps based on Patlak analysis provided excellent images and highly valuable quantitative information.

Conclusions

⁶⁸Ga-P15-041 PET/CT, offering a rapid bone scan and high contrast images in minutes, is superior to the current method of choice in detecting bone metastases. It is reasonable to suggest that ⁶⁸Ga-P15-041 PET/CT could become a valuable routine nuclear medicine procedure in providing excellent images for detecting bone metastases in cancer patients. ⁶⁸Ga-P15-041 could become a valuable addition expanding the collection of ⁶⁸Ga-based routine nuclear medicine procedures where ¹⁸F fluoride is not currently available.

Computerized Tomography (CT) Updates and Challenges in Diagnosis of Bone Metastases During Prostate Cancer

Prostate cancer is one of the most common cancers in men. This cancer is often associated with indolent tumors with little or no lethal potential. Some of the patients with aggressive prostate cancer have increased morbidity and early deaths. A major complication in advanced prostate cancer is bone metastasis that mainly results in pain, pathological fractures, and compression of spinal nerves. These complications in turn cause severe pain radiating to the extremities and possibly sensory as well as motor disturbances. Further, in patients with a high risk of metastases, treatment is limited to palliative therapies. Therefore, accurate methods for the detection of bone metastases are essential. Technical advances such as single-photon emission computed tomography/ computed tomography (SPECT/CT) have emerged after the introduction of bone scans. These advanced methods allow tomographic image acquisition and help in attenuation correction with anatomical co-localization. The use of positron emission tomography/CT (PET/CT) scanners is also on the rise. These PET scanners are mainly utilized with 18F-sodium-fluoride (NaF), in order to visualize the skeleton and possible changes. Moreover, NaF PET/CT is associated with higher tracer uptake, increased target-to-background ratio and has a higher spatial resolution. However, these newer technologies have not been adopted in clinical guidelines due to lack of definite evidence in support of their use in bone metastases cases. The present review article is focused on current perspectives and challenges of computerized tomography (CT) applications in cases of bone metastases during prostate cancer.

Spatiotemporal Statistical Shape Model for Temporal Shape Change Analysis of Adult Brain

BACKGROUND

This study presents a novel method of constructing a spatiotemporal statistical shape model (st-SSM) for adult brain. St-SSM is an extension of statistical shape model (SSM) in the temporal domain which will represent the statistical variability of shape as well as the temporal change of statistical variance with respect to time.

AIMS

Expectation-Maximization (EM) based weighted principal component analysis (WPCA) using a temporal weight function is applied where the eigenvalues of each data are estimated by Estep using temporal eigenvectors, and M-step updates Eigenvectors in order to maximize the variance. Both E and M-step are iterated until updating vectors reaches the convergence point. A weight parameter for each subject is allocated in accordance with the subject's age to calculate the weighted variance. A Gaussian function is utilized to define the weight function. The center of the function is a time point while the variance is a predefined parameter.

METHODS

The proposed method constructs adult brain st-SSM by changing the time point between minimum to maximum age range with a small interval. Here, the eigenvectors changes with aging. The feature vector of representing adult brain shape is extracted through a level set algorithm. To validate the method, this study employed 103 adult subjects (age: 22 to 93 y.o. with Mean ± SD = 59.32±16.89) from OASIS database. st-SSM was constructed for time point 40 to 90 with a step of 2.

RESULTS

We calculated the temporal deformation change between two-time points and evaluated the corresponding difference to investigate the influence of analysis parameter. An application of the proposed model is also introduced which involves Alzheimer's disease (AD) identification utilizing support vector machine.

CONCLUSION

In this study, st-SSM based adult brain shape feature extraction and classification techniques are introduced to classify between normal and AD subject as an application.

Degeneration in the Zygapophysial Joint of the Fifth Lumbar Vertebra: The V-Shaped Sign Revealed by Bone Scintigraphy

Objective

The aim of the study was to explore the nature of a V-shaped sign in the backbone of the fifth lumbar vertebra revealed by whole-body bone scintigraphy (WBBS).

Methods

A local single-photon emission computed tomography (SPECT) scan plus a computed tomography (CT) scan were performed on 41 patients in our department who had a V-shaped sign in the backbone of the fifth lumbar vertebra detected by WBBS. Image fusion was conducted to understand the manifestations of the changes in the V-shaped sign in the CT images in WBBS and to determine the nature of the lesion.

Results

All 41 patients presented with degenerative changes observed in the bilateral posterior zygapophysial joint of the fifth lumbar vertebra in the CT imaging bone window, bone hyperplasia of the articular process, joint surface hardening, and a joint gap. The vacuum sign could also be seen in some of these patients.

Conclusion

The typical V-shaped sign in the posterior zygapophysial joint of the fifth lumbar vertebra revealed by WBBS suggests degenerative changes in the zygapophysial joint of the fifth lumbar vertebra.

Simultaneous PET/MRI in the Evaluation of Breast and Prostate Cancer Using Combined Na[18F] F and [18F]FDG: a Focus on Skeletal Lesions

PURPOSE

The purpose of this study is to prospectively evaluate the performance of sodium ¹⁸F]fluoride (Na[¹⁸F]F)/2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) simultaneous time-of-flight enabled positron emission tomography (PET)/magnetic resonance imaging (MRI) for the detection of skeletal metastases in selected patients with advanced breast and prostate cancers.

PROCEDURE

The institutional review board approved this HIPAA-compliant protocol. Written informed consent was obtained from each patient. A total of 74 patients (23 women and 51 men with breast and prostate cancer, respectively) referred for standard-of-care whole-body bone scintigraphy (WBBS) were enrolled in this prospective study. All patients underwent a [^99mTc]methyldiphosphonate ([^99mTc]MDP) WBBS followed by Na[¹⁸F]F/[¹⁸F]FDG PET/MRI. Lesions detected by each imaging modality were tabulated and a lesion-based and patient-based analysis was conducted.

RESULTS

On a patient-based analysis, [^99mTc]MDP WBBS identified skeletal lesions in 37 patients and PET/MRI in 45 patients. On a lesion-based analysis, WBBS identified a total of 81 skeletal lesions, whereas PET/MRI identified 140 lesions. Additionally, PET/MRI showed extra-skeletal lesions in 19 patients, including lymph nodes (16), prostate (4) lung (3), and liver (2) lesions.

CONCLUSIONS

The ability of Na[¹⁸F]F/[¹⁸F]FDG PET/MRI to identify more skeletal lesions than ^99mTc-MDP WBBS and to additionally identify extra-skeletal disease may be beneficial for patient care and represent an alternative to the single modalities performed separately. Na[¹⁸F]F/[¹⁸F]FDG PET/MRI is a promising approach for evaluation of skeletal and extra-skeletal lesions in a selected population of breast and prostate cancer patients.

Comparison of PET/CT and MRI in the Diagnosis of Bone Metastasis in Prostate Cancer Patients: A Network Analysis of Diagnostic Studies

BACKGROUND

Accurate diagnosis of bone metastasis status of prostate cancer (PCa) is becoming increasingly more important in guiding local and systemic treatment. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) have increasingly been utilized globally to assess the bone metastases in PCa. Our meta-analysis was a high-volume series in which the utility of PET/CT with different radioligands was compared to MRI with different parameters in this setting.

MATERIALS AND METHODS

Three databases, including Medline, Embase, and Cochrane Library, were searched to retrieve original trials from their inception to August 31, 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The methodological quality of the included studies was assessed by two independent investigators utilizing Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A Bayesian network meta-analysis was performed using an arm-based model. Absolute sensitivity and specificity, relative sensitivity and specificity, diagnostic odds ratio (DOR), and superiority index, and their associated 95% confidence intervals (CI) were used to assess the diagnostic value.

RESULTS

Forty-five studies with 2,843 patients and 4,263 lesions were identified. Network meta-analysis reveals that 68Ga-labeled prostate membrane antigen (68Ga-PSMA) PET/CT has the highest superiority index (7.30) with the sensitivity of 0.91 and specificity of 0.99, followed by 18F-NaF, 11C-choline, 18F-choline, 18F-fludeoxyglucose (FDG), and 18F-fluciclovine PET/CT. The use of high magnetic field strength, multisequence, diffusion-weighted imaging (DWI), and more imaging planes will increase the diagnostic value of MRI for the detection of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT was performed in the detection of bone metastasis on patient-based level (sensitivity, 0.94 vs. 0.91; specificity, 0.94 vs. 0.96; superiority index, 4.43 vs. 4.56).

CONCLUSIONS

68Ga-PSMA PET/CT is recommended for the diagnosis of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT should be performed in the detection of bone metastasis.

Is 99m Tc bone scintigraphy necessary in the preoperative workup for patients with cT1N0 subsolid lung cancer? A prospective multicenter cohort study

BACKGROUND

^99m Tc bone scintigraphy (BS) is still the most common approach for the evaluation of bone metastasis in China. The purpose of this study was to investigate the necessity of BS as part of a routine preoperative workup for patients with cT1N0 subsolid lung cancer.

METHODS

This was a prospective multicenter clinical trial (NCT03689439). Patients with cT1N0 subsolid nodules who were candidates for surgical resection were consecutively enrolled into the study. BS was performed preoperatively. The surgical plan could be changed if a positive result was detected. The primary endpoint was the incidence rate of the surgical plan being changed because of positive BS results. The secondary endpoint was the rate of positive BS findings and the rate of related complications.

RESULTS

From November 2018 to July 2019, 691 patients were enrolled into the study. None of the patients had positive BS results and no surgical plans were changed by BS findings. There were 222 male and 469 female patients. The average age was 54.8 ± 3.7 years old. The average tumor diameter was 14.9 ± 4.2 mm. There were 282 patients with pure GGO nodules and 409 with part-solid nodules. A total of 470 patients had a single nodule, while 221 patients had multifocal lesions. The number of patients whose pathological diagnosis was invasive adenocarcinoma, minimally invasive adenocarcinoma, adenocarcinoma in situ and mucinous adenocarcinoma was 357, 293, 32 and nine, respectively. The number of patients who underwent lobectomy, segmentectomy and wedge resection was 234, 199 and 258, respectively.

CONCLUSIONS

^99m Tc bone scintigraphy is unnecessary in the preoperative workup for patients with cT1N0 subsolid lung cancer.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: In this prospective study of 691 patients with cT1N0 subsolid lung cancer, no surgical plans were affected by positive bone scan findings.

WHAT THIS STUDY ADDS

We suggest physicians consider canceling BS from preoperative workup for cT1 subsolid lung cancer patients. Clinical trial registry number: NCT03689439.

Application of PET Tracers in Molecular Imaging for Breast Cancer

PURPOSE OF REVIEW

Molecular imaging with positron emission tomography (PET) is a powerful tool to visualize breast cancer characteristics. Nonetheless, implementation of PET imaging into cancer care is challenging, and essential steps have been outlined in the international "imaging biomarker roadmap." In this review, we identify hurdles and provide recommendations for implementation of PET biomarkers in breast cancer care, focusing on the PET tracers 2-[18F]-fluoro-2-deoxyglucose ([18F]-FDG), sodium [18F]-fluoride ([18F]-NaF), 16α-[18F]-fluoroestradiol ([18F]-FES), and [89Zr]-trastuzumab.

RECENT FINDINGS

Technical validity of [18F]-FDG, [18F]-NaF, and [18F]-FES is established and supported by international guidelines. However, support for clinical validity and utility is still pending for these PET tracers in breast cancer, due to variable endpoints and procedures in clinical studies. Assessment of clinical validity and utility is essential towards implementation; however, these steps are still lacking for PET biomarkers in breast cancer. This could be solved by adding PET biomarkers to randomized trials, development of imaging data warehouses, and harmonization of endpoints and procedures.

Phantom and clinical evaluation of bone SPECT/CT image reconstruction with xSPECT algorithm

BACKGROUND

Two novel methods of image reconstruction, xSPECT Quant (xQ) and xSPECT Bone (xB), that use an ordered subset conjugate gradient minimizer (OSCGM) for SPECT/CT reconstruction have been proposed. The present study compares the performance characteristics of xQ, xB, and conventional Flash3D (F3D) reconstruction using images derived from phantoms and patients.

METHODS

A custom-designed body phantom for bone SPECT was scanned using a Symbia Intevo (Siemens Healthineers), and reconstructed xSPECT images were evaluated. The phantom experiments proceeded twice with different activity concentrations and sphere sizes. A phantom with 28-mm spheres containing a 99mTc-background and tumor-to-normal bone ratios (TBR) of 1, 2, 4, and 10 were generated, and convergence property against various TBR was evaluated across 96 iterations. A phantom with four spheres (13-, 17-, 22-, and 28-mm diameters), containing a 99mTc-background at TBR4, was also generated. The full width at half maximum of an imaged spinous process (10 mm), coefficients of variance (CV), contrast-to-noise ratio (CNR), and recovery coefficients (RC) were evaluated after reconstructing images of a spine using Flash 3D (F3D), xQ, and xB. We retrospectively analyzed images from 20 patients with suspected bone metastases (male, n = 13) which were acquired using [99mTc]Tc-(H)MDP SPECT/CT, then CV and standardized uptake values (SUV) at the 4th vertebral body (L4) were compared after xQ and xB reconstruction in a clinical setup.

RESULTS

Mean activity concentrations with various TBR converged according to increasing numbers of iterations. The spatial resolution of xB was considerably superior to xQ and F3D, and it approached almost the actual size regardless of the iteration numbers during reconstruction. The CV and RC were better for xQ and xB than for F3D. The CNR peaked at 24 iterations for xQ and 48 iterations for F3D and xB, respectively. The RC between xQ and xB significantly differed at lower numbers of iterations but were almost equivalent at higher numbers of iterations. The reconstructed xQ and xB images of the clinical patients showed a significant difference in the SUVmax and SUVpeak.

CONCLUSIONS

The reconstructed xQ and xB images were more accurate than those reconstructed conventionally using F3D. The xB for bone SPECT imaging offered essentially unchanged spatial resolution even when the numbers of iterations did not converge. The xB reconstruction further enhanced SPECT image quality using CT data. Our findings provide important information for understanding the performance characteristics of the novel xQ and xB algorithms.

Molecular Imaging of Bone Metastases and Their Response to Therapy

Bone metastases are common, especially in more prevalent malignancies such as breast and prostate cancer. They cause significant morbidity and draw on health-care resources. Molecular and hybrid imaging techniques, including SPECT/CT, PET/CT, and whole-body MRI with diffusion-weighted imaging, have improved diagnostic accuracy in staging the skeleton compared with previous standard imaging methods, allowing earlier tailored treatment. With the introduction of several effective treatment options, it is now even more important to detect and monitor response in bone metastases accurately. Conventional imaging, including radiographs, CT, MRI, and bone scintigraphy, are recognized as being insensitive and nonspecific for response monitoring in a clinically relevant time frame. Early reports of molecular and hybrid imaging techniques, as well as whole-body MRI, promise an earlier and more accurate prediction of response versus nonresponse but have yet to be adopted routinely in clinical practice. We summarize the role of new molecular and hybrid imaging methods, including SPECT/CT, PET/CT, and whole-body MRI. These modalities are associated with improvements in diagnostic accuracy for the staging and response assessment of skeletal metastases over standard imaging methods, being able to quantify biologic processes related to the bone microenvironment as well as tumor cells. The described improvements in the imaging of bone metastases and their response to therapy have led to adoption of some of these methods into routine clinical practice in some centers. These methods also provide a better way to assess the treatment response of bone metastases in clinical trials.

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.

The Established Nuclear Medicine Modalities for Imaging of Bone Metastases

Background:

The skeleton is one of the frequent site of metastases in advanced cancer. Prostate, breast and renal cancers mostly metastasize to bone.

Discussion:

Malignant tumors lead to significant morbidity and mortality. Identification of bone lesions is a crucial step in diagnosis of disease at early stage, monitoring of disease progression and evaluation of therapy. Diagnosis of cancer metastases is based on uptake of bone-targeted radioactive tracer at different bone remodeling sites.

Conclusion:

This manuscript summarizes already established and evolving nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET, PET/CT) for imaging of bone metastases.

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.

Molecular imaging of bone metastases using tumor-targeted tracers

Bone metastasis is a disastrous manifestation of most malignancies, especially in breast, prostate and lung cancers. Since asymptomatic bone metastases are not uncommon, early detection, precise assessment, and localization of them are very important. Various imaging modalities have been employed in the setting of diagnosis of bone metastasis, from plain radiography and bone scintigraphy to SPECT, SPECT/CT, PET/CT, MRI. However, each modality showed its own limitation providing accurate diagnostic performance. In this regard, various tumor-targeted radiotracers have been introduced for molecular imaging of bone metastases using modern hybrid modalities. In this article we review the strength of different cancer-specific radiopharmaceuticals in the detection of bone metastases. As shown in the literature, among various tumor-targeted tracers, 68Ga DOTA-conjugated-peptides, 68Ga PSMA, 18F DOPA, 18F galacto-RGD integrin, 18F FDG, 11C/18F acetate, 11C/18F choline, 111In octreotide, 123/131I MIBG, 99mTc MIBI, and 201Tl have acceptable capabilities in detecting bone metastases depending on the cancer type. However, different study designs and gold standards among reviewed articles should be taken into consideration.

Machine learning for differentiating metastatic and completely responded sclerotic bone lesion in prostate cancer: a retrospective radiomics study

OBJECTIVE

Using CT texture analysis and machine learning methods, this study aims to distinguish the lesions imaged via 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/CT as metastatic and completely responded in patients with known bone metastasis and who were previously treated.

METHODS

We retrospectively reviewed the 68Ga-PSMA PET/CT images of 75 patients after treatment, who were previously diagnosed with prostate cancer and had known bone metastasis. A texture analysis was performed on the metastatic lesions showing PSMA expression and completely responded sclerotic lesions without PSMA expression through CT images. Textural features were compared in two groups. Thus, the distinction of metastasis/completely responded lesions and the most effective parameters in this issue were determined by using various methods [decision tree, discriminant analysis, support vector machine (SVM), k-nearest neighbor (KNN), ensemble classifier] in machine learning.

RESULTS

In 28 of the 35 texture analysis findings, there was a statistically significant difference between the two groups. The Weighted KNN method had the highest accuracy and area under the curve, has been chosen as the best model. The weighted KNN algorithm was succeeded to differentiate sclerotic lesion from metastasis or completely responded lesions with 0.76 area under the curve. GLZLM_SZHGE and histogram-based kurtosis were found to be the most important parameters in differentiating metastatic and completely responded sclerotic lesions.

CONCLUSIONS

Metastatic lesions and completely responded sclerosis areas in CT images, as determined by 68Ga-PSMA PET, could be distinguished with good accuracy using texture analysis and machine learning (Weighted KNN algorithm) in prostate cancer.

ADVANCES IN KNOWLEDGE

Our findings suggest that, with the use of newly emerging software, CT imaging can contribute to identifying the metastatic lesions in prostate cancer.

CT temporal subtraction improves early detection of bone metastases compared to SPECT

OBJECTIVES

To compare observer performance of detecting bone metastases between bone scintigraphy, including planar scan and single-photon emission computed tomography, and computed tomography (CT) temporal subtraction (TS).

METHODS

Data on 60 patients with cancer who had undergone CT (previous and current) and bone scintigraphy were collected. Previous CT images were registered to the current ones by large deformation diffeomorphic metric mapping; the registered previous images were subtracted from the current ones to produce TS. Definitive diagnosis of bone metastases was determined by consensus between two radiologists. Twelve readers independently interpreted the following pairs of examinations: NM-pair, previous and current CTs and bone scintigraphy, and TS-pair, previous and current CTs and TS. The readers assigned likelihood levels to suspected bone metastases for diagnosis. Sensitivity, number of false positives per patient (FPP), and reading time for each pair of examinations were analysed for evaluating observer performance by performing the Wilcoxon signed-rank test. Figure-of-merit (FOM) was calculated using jackknife alternative free-response receiver operating characteristic analysis.

RESULTS

The sensitivity of TS was significantly higher than that of bone scintigraphy (54.3% vs. 41.3%, p = 0.006). FPP with TS was significantly higher than that with bone scintigraphy (0.189 vs. 0.0722, p = 0.003). FOM of TS tended to be better than that of bone scintigraphy (0.742 vs. 0.691, p = 0.070).

CONCLUSION

Sensitivity of TS in detecting bone metastasis was significantly higher than that of bone scintigraphy, but still limited to 54%. TS might be superior to bone scintigraphy for early detection of bone metastasis.

KEY POINTS

• Computed tomography temporal subtraction was helpful in early detection of bone metastases. • Sensitivity for bone metastasis was higher for computed tomography temporal subtraction than for bone scintigraphy. • Figure-of-merit of computed tomography temporal subtraction was better than that of bone scintigraphy.

18F-NaF-PET/CT for the detection of bone metastasis in prostate cancer: a meta-analysis of diagnostic accuracy studies

PURPOSE

This meta-analysis aims to establish the diagnostic performance of ¹⁸F-NaF-PET/CT for the detection of bone metastases in prostate cancer patients. The performance of ¹⁸F-NaF-PET/CT was compared with other imaging techniques in the same cohort of patients.

METHODS

A systematic search was performed in PubMed/Medline and EMBASE (last Updated, September 28, 2018). Studies with histopathology confirmation and/or clinical/imaging follow-up as reference standard were eligible for inclusion.

RESULTS

A total of 14 studies were included. Twelve studies including 507 patients provided per-patient basis information. The pooled sensitivity, specificity, diagnostic odds ratio (DOR) and the area under the summary receiver operating characteristics curve (AUC) of ¹⁸F-NaF-PET/CT for the detection of bone metastases were 0.98 (95% CI 0.95-0.99), 0.90 (95% CI 0.86-0.93), 123.2 and 0.97, respectively. Seven studies provided the lesion-based accuracy information of 1812 lesions identified on ¹⁸F-NaF-PET/CT with the pooled sensitivity, specificity, DOR and AUC of 0.97 (95% CI 0.95-0.98), 0.84 (95% CI 0.81-0.87), 206.8 and 0.97, respectively. The overall diagnostic performance of ¹⁸F-NaF-PET/CT is superior to ^99mTc-bone scintigraphy (AUC 0.842; P < 0.001; four studies) and ^99mTc-SPECT (AUC 0.896; P < 0.001, four studies). Compared to ¹⁸F NaF-PET/CT, whole-body MRI with diffusion-weighted imaging (DWI) was shown to have lower sensitivity (0.83, 95% CI 0.68-0.93), with no significant difference in the overall performance (AUC 0.947; P = 0.18, four studies).

CONCLUSION

¹⁸F-NaF-PET/CT has excellent diagnostic performance in the detection of bone metastases in staging and restaging of high-risk prostate cancer patients. The performance of ¹⁸F-NaF-PET/CT is superior to ^99mTc bone scintigraphy and SPECT, and comparable to DWI-MRI.

Metastatic Seeding Attacks Bone Marrow, Not Bone: Rectifying Ongoing Misconceptions

Conventional modalities, such as bone scintigraphy, are commonly used to assess osseous abnormalities in skeletal metastasis. Fluorine-18 (¹⁸F)-sodium fluoride (NaF) PET similarly portrays osteoblastic activity but with improved spatial and contrast resolution and more accurate anatomic localization. However, these modalities rely on indirect evidence for tumor activity. PET imaging with ¹⁸F-fluorodeoxyglucose (FDG) and tumor-specific tracers may have an increased role by directly portraying the metabolic activity of cancer cells, which are often seeded in bone marrow and cause osseous disease after initial latency. This article describes the utility and limitations of these modalities in assessing skeletal metastases.

Nuclear Medicine Imaging Techniques for Detection of Skeletal Metastases in Breast Cancer

Bone is the most common site of metastases from advanced breast cancer. Whole-body bone scintigraphy has been most frequently used in the process of managing cancer patients; its advantage is that it provides rapid whole-body imaging for screening of osteoblastic or sclerotic/mixed bone metastases at reasonable cost. Recent advanced techniques, such as single-photon emission computed tomography (SPECT)/CT, quantitative analysis, and bone scan index, contribute to better understanding of the disease state. More recent advances in machines and PET drugs improve the staging of the skeleton with higher sensitivity and specificity.

Whole-body 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) for staging locally advanced breast cancer: A prospective study from a tertiary cancer centre in south India

Background & objectives:

Locally advanced breast cancer (LABC) is associated with substantial risk of occult metastases. The patients with LABC have high rate of systemic relapse, suggesting inadequacy of the current conventional staging in detecting the occult metastatic spread. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) is a new modality in the staging of breast cancer patients. Hence, this study was conducted to evaluate the role of ¹⁸F-FDG PET/CT in initial staging of LABC and to compare it with conventional methods.

Methods:

This prospective study included biopsy-confirmed female patients diagnosed with LABC meeting the selection criteria and attending surgical, medical and radiation oncology departments of a tertiary care centre in south India, from April 2013 to December 2014. Conventional workup included serum chemistry, mammogram, bone scan, contrast-enhanced CT (CECT) chest and upper abdomen and ultrasound abdomen and pelvis. All patients following conventional workup underwent ¹⁸F-FDG PET/CT.

Results:

In this study, 61 women with LABC underwent both conventional workup and ¹⁸F-FGD PET/CT. The ¹⁸F-FDG PET/CT, in comparison to conventional workup, revealed unsuspected N3 nodal disease in 11 more patients, revealed distant metastasis in seven more patients and also detected extra sites of metastasis in five patients. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT to detect distant metastasis were 95, 98, 95, 98 and 97 per cent, respectively, whereas the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of conventional imaging to detect distant metastasis were 65, 93, 81, 84 and 84 per cent, respectively.

Interpretation & conclusions:

The ¹⁸F-FDG PET/CT was found to be more accurate than conventional imaging for staging and modified stage and treatment in 30 and 38 per cent of patients, respectively. It was particularly useful in detecting occult distant metastasis and N3 nodal disease with an added advantage of examining whole body in single session. However, CECT chest was superior over ¹⁸F-FDG PET/CT for detecting pulmonary metastasis.

A prospective study on dual time 18F-FDG-PET/CT in high-risk prostate cancer patients

Objective

This proof of concept study investigated whether dual time point FDG-PET/CT with image acquisition after 1 and 3 h could be useful in preoperative staging of patients undergoing robot-assisted radical prostatectomy and extended pelvic lymph node dissection for high-risk prostate cancer.

Results

Twenty patients with high-risk prostate cancer underwent dual time point FDG-PET/CT before undergoing surgery. Histologically confirmed lymph node metastases were found in 9/20 (45%). A median of 19 (range 10–41; n = 434) lymph nodes were removed per patient. Pelvic lymph nodes with detectable FDG uptake were seen in two patients only, but the FDG-avid lesion on PET did not correspond with pathological findings in either patient. We found a significant increase in maximal standardized uptake value of the prostate of around 30% between early and late imaging. We found no correlation between clinical findings after radical prostatectomy and PET measurements.

Pediatric Musculoskeletal Imaging: The Indications for and Applications of PET/Computed Tomography

The use of PET/computed tomography (CT) for the evaluation and management of children, adolescents, and young adults continues to expand. The principal tracer used is 18F-fluorodeoxyglucose and the principal indication is oncology, particularly musculoskeletal neoplasms. The purpose of this article is to review the common applications of PET/CT for imaging of musculoskeletal issues in pediatrics and to introduce the use of PET/CT for nononcologic issues, such as infectious/inflammatory disorders, and review the use of 18F-sodium fluoride in trauma and sports-related injuries.

Comparison of 18F-NaF PET/CT and 18F-FDG PET/CT for Detection of Skull-Base Invasion and Osseous Metastases in Nasopharyngeal Carcinoma

Our study aimed at comparing the diagnostic value of 18F-NaF positron emission tomography-computed tomography (PET/CT) and 18F-fluorodeoxyglucose (FDG) PET/CT for detection of skull-base invasion and osseous metastases in patients with nasopharyngeal carcinoma (NPC). Our study retrospectively analyzed 45 patients with pathologically proven NPC. They all underwent both 18F-NaF PET/CT and 18F-FDG PET/CT within a 7-day interval. Bone metastases were confirmed by follow-up using PET/CT, enhance-contrast computed tomography (CT), and magnetic resonance image (MRI). These two examinations were compared using per-patient-based analysis and per-lesion-based analysis. 18F-NaF PET/CT detected 27 patients with skull-base invasion, whereas 18F-FDG PET/CT detected 17 patients. 18F-NaF PET/CT and 18F-FDG PET/CT differed significantly in diagnosing skull-base invasion (p=0.02) and sensitivity (p=0.008). The sensitivity, specificity, and agreement rate of 18F-NaF PET/CT for detecting bone metastatic lesions were 98.3%, 65.7%, and 92.9%, respectively; these values were 42.9%, 97.1%, and 51.9%, respectively, for 18F-FDG PET/CT. 18F-NaF PET/CT and 18F-FDG PET/CT differed significantly in the number of osseous metastases detected (t=2.45, p=0.18) sensitivity (p < 0.0001) and specificity (p=0.003). In patients with nasopharyngeal carcinoma, 18F-NaF PET/CT assessed invasion of the skull base better and detected more osseous metastases than 18F-FDG PET/CT.

Prospective comparison of 68Ga-PSMA PET/CT, 18F-sodium fluoride PET/CT and diffusion weighted-MRI at for the detection of bone metastases in biochemically recurrent prostate cancer

PURPOSE

To prospectively compare diagnostic accuracies for detection of bone metastases by ⁶⁸Ga-PSMA PET/CT, ¹⁸F-NaF PET/CT and diffusion-weighted MRI (DW₆₀₀-MRI) in prostate cancer (PCa) patients with biochemical recurrence (BCR).

METHODS

Sixty-eight PCa patients with BCR participated in this prospective study. The patients underwent ⁶⁸Ga-PSMA PET/CT, a ¹⁸F-NaF PET/CT and a DW₆₀₀-MRI (performed in accordance with European Society of Urogenital Radiology guidelines, with b values of 0 and 600 s/mm²). Bone lesions were categorized using a three-point scale (benign, malignant or equivocal for metastases) and a dichotomous scale (benign or metastatic) for each imaging modality by at least two experienced observers. A best valuable comparator was defined for each patient based on study-specific imaging, at least 12 months of clinical follow-up and any imaging prior to the study and during follow-up. Diagnostic performance was assessed using a sensitivity analysis where equivocal lesions were handled as non-metastatic and then as metastatic.

RESULTS

Ten of the 68 patients were diagnosed with bone metastases. On a patient level, sensitivity, specificity and the area under the curve (AUC) by receiver operating characteristic analysis were, respectively, 0.80, 0.98-1.00 and 0.89-0.90 for ⁶⁸Ga-PSMA PET/CT (n = 68 patients); 0.90, 0.90-0.98 and 0.90-0.94 for ¹⁸NaF PET/CT (n = 67 patients); and 0.25-0.38, 0.87-0.92 and 0.59-0.62 for DW₆₀₀-MRI (n = 60 patients). The diagnostic performance of DW₆₀₀-MRI was significantly lower than that of ⁶⁸Ga-PSMA PET/CT and ¹⁸NaF PET/CT for diagnosing bone metastases (p < 0.01), and no significant difference in the AUC was seen between ⁶⁸Ga-PSMA PET/CT and ¹⁸NaF PET/CT (p = 0.65).

CONCLUSION

⁶⁸Ga-PSMA PET/CT and ¹⁸F-NaF PET/CT showed comparable and high diagnostic accuracies for detecting bone metastases in PCa patients with BCR. Both methods performed significantly better than DW₆₀₀-MRI, which was inadequate for diagnosing bone metastases when conducted in accordance with European Society of Urogenital Radiology guidelines.

Functional and Hybrid Imaging of Bone Metastases

Bone metastases are common, cause significant morbidity, and impact on healthcare resources. Although radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy have frequently been used for staging the skeleton, these methods are insensitive and nonspecific for monitoring treatment response in a clinically relevant time frame. We summarize several recent reports on new functional and hybrid imaging methods including single photon emission CT/CT, positron emission tomography/CT, and whole-body MRI with diffusion-weighted imaging. These modalities generally show improvements in diagnostic accuracy for staging and response assessment over standard imaging methods, with the ability to quantify biological processes related to the bone microenvironment as well as tumor cells. As some of these methods are now being adopted into routine clinical practice and clinical trials, further evaluation with comparative studies is required to guide optimal and cost-effective clinical management of patients with skeletal metastases. © 2018 American Society for Bone and Mineral Research.

99mTc-HDP bone scintigraphy and 18F-sodiumfluoride PET/CT in primary staging of patients with prostate cancer

Introduction/Aim

Correct staging of patients with prostate cancer is important for treatment planning and prognosis. Although bone scintigraphy with ^99mTc-phosphonates (BS) is generally advised for staging by guidelines in high risk prostate cancer, this imaging technique is hampered by a high rate of inconclusive results and moderate accuracy. Potentially better imaging techniques for detection of bone metastases such as ¹⁸F-sodiumfluoride PET/CT (NaF PET/CT) are therefore being evaluated. In this observational cohort study we evaluate the performance and clinical impact of both BS and NaF PET/CT in primary staging of patients with prostate cancer.

Methods

The first of two cohorts consisted of patients who received a BS while the second included patients who received a NaF PET/CT for primary staging of prostate cancer. For both cohorts the number of positive, negative and equivocal findings, calculated diagnostic performance of the imaging modality in terms of sensitivity and specificity, as well as the impact on clinical management were studied. The ranges of the diagnostic performance were calculated both assuming that equivocal findings were positive and assuming that they were negative for bone metastases. For the NaF PET/CT cohort the number of patients with signs of lymph node metastases on low dose CT were also recorded, including the impact of these findings on clinical management.

Results

One-hundred-and-four patients underwent NaF PET/CT, whereas 122 patients underwent BS. Sensitivities of 97–100 and 84–95% and specificities of 98–100 and 72–100% were found on a patient basis for detection of bone metastases with NaF PET/CT and BS, respectively. Equivocal findings warranted further diagnostic procedures in 2% of the patients in the NaF cohort and in 16% in the BS cohort. In addition NaF PET/CT demonstrated lymph node metastases in 50% of the included patients, of which 25% showed evidence of lymph node metastases only.

Conclusion

Our data indicate better diagnostic performance of NaF PET/CT compared to BS for detection of bone metastases in primary staging of prostate cancer patients. Less equivocal findings are encountered with NaF PET/CT. Moreover, NaF PET/CT has additional value over BS since lymph node metastases are encountered frequently.

Using Imaging to Predict Treatment Response in Genitourinary Malignancies

CONTEXT

Over the previous2 decades, there have been numerous advancements in the diagnostic evaluation, therapeutic management, and postoperative assessment of genitourinary malignancies.

OBJECTIVE

To present a review of current and novel imaging modalities and their utility in the assessment of therapeutic response in the systemic management of renal, testicular, and prostate cancers.

EVIDENCE ACQUISITION

A PubMed/Medline search of the current published literature inclusive of prospective and retrospective original research, systematic reviews, and meta-analyses was conducted evaluating imaging modalities for renal cell carcinoma, prostate cancer, and testicular cancer. All relevant literature was individually reviewed and summarized to provide a concise description of the currently available imaging modalities and their efficacy in assessing treatment response of the genitourinary malignancies targeted in this review.

EVIDENCE SYNTHESIS

Conventional imaging techniques play a pivotal role in predicting the treatment response of genitourinary malignancies and have, therefore, been incorporated into clinical guidelines. Advancements in imaging technology have led to increased utilization for prognostication of a genitourinary cancer's response to therapy.

CONCLUSIONS

A good understanding of current recommended imaging techniques to evaluate treatment response in genitourinary malignancies is of paramount importance for today's clinician, who faces increasing treatment modalities.

PATIENT SUMMARY

In this review, we summarize available imaging modalities in the evaluation of treatment response in kidney, prostate, or testicular tumors. We believe that a good understanding of current imaging modalities is of paramount importance for healthcare providers treating these cancers.

Detection of distant metastases in patients with locally advanced breast cancer: role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and conventional imaging with computed tomography scans

OBJECTIVE

To evaluate positron emission tomography/computed tomography (PET/CT) and conventional imaging tests for the detection of distant metastases in patients with locally advanced breast cancer.

MATERIALS AND METHODS

We included 81 patients with breast cancer who had undergone ¹⁸F-fluorodeoxyglucose (FDG) PET/CT before treatment. Conventional imaging included the following: bone scintigraphy; chest X-ray (in 14.5%) or CT (in 85.5%); and abdominal ultrasound (in 10.8%), CT (in 87.8%), or magnetic resonance imaging (in 1.4%). Histopathology and clinical/imaging follow-up served as reference.

RESULTS

Distant metastases were observed in nine patients (11.1%). On patient-based analysis, conventional imaging identified distant metastases in all 9 patients. In one patient, the initial ¹⁸F-FDG PET/CT failed to demonstrate bone metastases that was evident on bone scintigraphy. In two patients, the CT scan failed to show extra-axillary lymph node metastases that were identified on ¹⁸F-FDG PET/CT. There was no significant difference between ¹⁸F-FDG PET/CT and conventional imaging in terms of their sensitivity for the detection of distant metastases in patients with locally advanced breast cancer.

CONCLUSION

This study showed that ¹⁸F-FDG PET/CT and conventional imaging with CT scans had similar sensitivity for the diagnosis of distant metastases in patients with locally advanced breast cancer. ¹⁸F-FDG PET/CT can add information about extra-axillary lymph node involvements.

Temporal Subtraction of Serial CT Images with Large Deformation Diffeomorphic Metric Mapping in the Identification of Bone Metastases

Purpose To determine the improvement of radiologist efficiency and performance in the detection of bone metastases at serial follow-up computed tomography (CT) by using a temporal subtraction (TS) technique based on an advanced nonrigid image registration algorithm. Materials and Methods This retrospective study was approved by the institutional review board, and informed consent was waived. CT image pairs (previous and current scans of the torso) in 60 patients with cancer (primary lesion location: prostate, n = 14; breast, n = 16; lung, n = 20; liver, n = 10) were included. These consisted of 30 positive cases with a total of 65 bone metastases depicted only on current images and confirmed by two radiologists who had access to additional imaging examinations and clinical courses and 30 matched negative control cases (no bone metastases). Previous CT images were semiautomatically registered to current CT images by the algorithm, and TS images were created. Seven radiologists independently interpreted CT image pairs to identify newly developed bone metastases without and with TS images with an interval of at least 30 days. Jackknife free-response receiver operating characteristics (JAFROC) analysis was conducted to assess observer performance. Reading time was recorded, and usefulness was evaluated with subjective scores of 1-5, with 5 being extremely useful and 1 being useless. Significance of these values was tested with the Wilcoxon signed-rank test. Results The subtraction images depicted various types of bone metastases (osteolytic, n = 28; osteoblastic, n = 26; mixed osteolytic and blastic, n = 11) as temporal changes. The average reading time was significantly reduced (384.3 vs 286.8 seconds; Wilcoxon signed rank test, P = .028). The average figure-of-merit value increased from 0.758 to 0.835; however, this difference was not significant (JAFROC analysis, P = .092). The subjective usefulness survey response showed a median score of 5 for use of the technique (range, 3-5). Conclusion TS images obtained from serial CT scans using nonrigid registration successfully depicted newly developed bone metastases and showed promise for their efficient detection. ^© RSNA, 2017 Online supplemental material is available for this article.

Skeletal Scintigraphy

BACKGROUND

Skeletal scintigraphy remains a valuable tool in the initial and subsequent evaluation of the skeletal system in patients with a diagnosis of primary or metastatic neoplasms.

METHODS

We discuss radiopharmaceuticals, nuclear medicine imaging techniques, and current as well as future oncological applications in the adult population. Pertinent literature was reviewed to describe the advantages and limitations of available technologies for the evaluation of skeletal metastatic disease. Evaluation of primary and metastatic skeletal disease using nuclear medicine and positron emission tomography techniques is discussed.

RESULTS

Skeletal scintigraphy provides valuable information in the initial evaluation for the presence of osteoblastic skeletal metastases. Incremental advances on available radiopharmaceuticals (fludeoxyglucose F 18, sodium fluoride F 18), coupled with advances in imaging techniques and imaging devices (single photon emission computed tomography/computed tomography, positron emission tomography/computed tomography, positron emission tomography/magnetic resonance imaging), have had a significant impact on sensitivity, specificity, and accuracy rates for the detection of skeletal metastases.

CONCLUSIONS

Skeletal scintigraphy has a significant role in the initial diagnosis, staging, restaging, and treatment monitoring of patients with cancer and primary skeletal or metastatic disease. The coupling of diagnostic and therapeutic nuclear medicine agents in the setting of osteoblastic skeletal metastases is a valuable tool for the treatment for certain cancer types, including prostate cancer, and may become more widely used to treat other histologies as more data on other tumor types (eg, breast cancer, osteosarcoma) become available.

Utility of PET/CT After Cryoablation for Early Identification of Local Tumor Progression in Osseous Metastatic Disease

OBJECTIVE

The purpose of this study is to evaluate the utility of combined PET/CT for the detection of early local tumor progression after cryoablation of bone metastases.

MATERIALS AND METHODS

A retrospective single-institution review revealed 61 consecutive patients with 80 separate bone metastases treated with cryoablation who were evaluated with a preablation PET/CT and at least two postablation PET/CT examinations between September 2007 and July 2015. Patients were excluded if they had local therapy or pathologic fracture after ablation. The patients were grouped according to postcryoablation disease status (i.e., local tumor progression or not) and PET radiotracer (i.e., ¹¹C-choline or ¹⁸F-FDG) used. The maximum standardized uptake value (SUV_max) ratio (i.e., ratio of SUV_max to blood pool) was calculated within each osseous metastasis before and after cryoablation, and these were then compared between groups.

RESULTS

Of the 61 patients and 80 ablations performed, 32 patients were imaged with FDG PET/CT and 29 were imaged with ¹¹C-choline PET/CT. Twenty-three patients imaged with FDG and 13 patients imaged with ¹¹C-choline had evidence of local tumor progression on all postablation PET/CT examinations. The SUV_max ratio was significantly higher in patients with local tumor progression on the first and most remote postcryoablation PET/CT examinations for both FDG and ¹¹C-choline (p < 0.001 in all cases). There was no significant difference in the postablation systemic therapy between the groups with and without local tumor progression.

CONCLUSION

Increased SUV_max ratio in patients after cryoablation for osseous metastatic disease should raise concern about local tumor progression independently of time after ablation.

Prospective comparison of whole-body bone SPECT and sodium 18F-fluoride PET in the detection of bone metastases from breast cancer

OBJECTIVE

The superiority of sodium F-fluoride PET (F-PET)/computed tomography (CT) over planar and single field-of-view single-photon emission computed tomography (SPECT) bone scintigraphy with Tc-methylene diphosphonate in bone metastases detection has been established. The present study prospectively compares whole-body Tc-methylene diphosphonate SPECT (WB-SPECT) and F-PET performance indices for the detection of bone metastases in breast cancer.

METHODS

A total of 41 pairs of studies in female breast cancer patients (average age 58 years, range 30-75) were included. Half-time WB-SPECT and F-PET/CT were performed at a 4-day average interval (range 0-36 days), with subsequent fusion of CT to WB-SPECT. Two readers independently interpreted the studies, with differences resolved by consensus. Composite gold standard included the CT component of the F-PET/CT study with follow-up CT, MRI, F-fluoro-deoxyglucose-PET/CT, and bone scans.

RESULTS

On patient-based analysis, metastases were diagnosed in 21 patients, with 19 patients detected by WB-SPECT and 21 with F-PET, the latter being the only modality to detect a single metastasis in two patients. The sensitivity of WB-SPECT and F-PET was 90 and 100% (P=NS), and the specificity were 95 and 85%, respectively (P=NS). On lesion-based analysis, 284 total sites of increased uptake were found. WB-SPECT detected 171/284 (60%) and F-PET 268/284 (94%) lesions, with good interobserver agreement for WB-SPECT (κ=0.679) and excellent agreement for F-PET (κ=0.798). The final analysis classified 204 lesions as benign and 80 as metastases. WB-SPECT identified 121 benign and 50 malignant sites compared with 192 and 76, respectively, for F-PET. WB-SPECT and F-PET had a sensitivity of 63 vs. 95%, P-value of less than 0.001, and a specificity of 97 vs. 96% (P=NS), respectively, on lesion-based analysis.

CONCLUSION

F-PET had higher sensitivity for the diagnosis of bone metastases from breast cancer compared with WB-SPECT, showing a statistically significant 32% increase on lesion-based analysis.