The EANM practice guidelines for bone scintigraphy

Inter- and intraobserver agreement in standard and ultra-fast single-photon emission computed tomography/computed tomography for the assessment of bone metastases

OBJECTIVE

To investigate inter- and intraobserver agreement using standard (std)-single-photon emission computed tomography/computed tomography (SPECT/CT) or ultra-fast acquisition (UF)-SPECT/CT as an add-on to planar whole-body bone scintigraphy (WB-BS) for the detection of bone metastases in patients with known cancer.

METHODS

Images from patients (n = 104) participating in a prospective trial comparing SPECT/CT as an add-on to WB-BS with two different acquisition methods (std-SPECT/CT; 20 s per view, 32 views and UF-SPECT/CT; 16 views of 10 s per view) were included. The combinations of WB-BS with the two different SPECT/CT acquisition methods were independently evaluated by two experienced observers using a three-point scale (M0: no metastases, Me: equivocal for bone metastases and M1: bone metastases). The observers re-evaluated the scans 6 months later. Inter- and intraobserver agreement was calculated using linear weighted kappa.

RESULTS

The linear weighted kappa for the interobserver agreement was 0.78 [95% confidence interval (CI) 0.61-0.94] for WB-BS with std-SPECT/CT and 0.84 (95% CI 0.67-1.00) for WB-BS with UF-SPECT/CT. Similar values were observed for the intraobserver agreement, in which the linear weighted kappa was 0.76 (95% CI 0.60-0.92) and 0.73 (95% CI 0.57-0.90) for std-SPECT/CT and UF-SPECT/CT, respectively.

CONCLUSION

Satisfactory inter- and intraobserver agreement was seen for both acquisition methods, emphasizing that the use of SPECT/CT as an add-on to WB-BS is a robust method for the detection of bone metastases even when conducted with a very short acquisition time.

SPECT/CT: Standing on the Shoulders of Giants, It Is Time to Reach for the Sky!

Twenty years ago, SPECT/CT became commercially available, combining the strengths of both techniques: the diagnostic sensitivity of SPECT and the anatomic detail of CT. Other benefits initially included attenuation correction of SPECT reconstructions, ultimately evolving to correction techniques that would enable absolute tracer uptake quantification. Recent developments in SPECT hardware include solid-state digital systems with higher sensitivity and resolution, using novel collimator designs based on tungsten. Similar advances in CT technology have been introduced in hybrid SPECT/CT systems, replacing low-end x-ray tubes with high-end multislice CT scanners equipped with iterative reconstruction, metal artifact reduction algorithms, and dual-energy capabilities. More recently, the design of whole-body SPECT/CT systems has taken another major leap with the introduction of a ring-shaped gantry equipped with multiple movable detectors surrounding the patient. These exciting developments have fueled efforts to develop novel SPECT radiopharmaceuticals, creating new chelators and prosthetic groups for radiolabeling. Innovative SPECT radionuclide pairs have now become available for radiolabeling with the potential for use as theranostic agents. The growth of precision medicine and the associated need for accurate radionuclide treatment dosimetry will likely drive the use of SPECT/CT in the near future. In addition, expanding clinical applications of SPECT/CT in other areas such as orthopedics offer exciting opportunities. Although it is true that the SPECT/CT ecosystem has seen several challenges during its development over the past 2 decades, it is now a feature-rich and mature tool ready for clinical prime time.

Evaluation of bone metastasis burden as an imaging biomarker by quantitative single-photon emission computed tomography/computed tomography for assessing prostate cancer with bone metastasis: a phantom and clinical study

Metabolic bone volume (MBV), standardized uptake value (SUV), and total bone uptake (TBU) are new imaging biomarkers for quantitative bone single-photon emission computed tomography/computed tomography. The purpose of this study was to validate the quantitative accuracy and utility of MBV, SUV_mean, and TBU for the assessment of bone metastases in prostate cancer. We used a bone-specific phantom with four hot spheres (φ = 13, 17, 22, 28 mm) filled with different Tc-99 m activities to simulate uptake ratios of 3 and 7, corresponding to normal and metastatic values. We calculated the error ratio (%Error) by comparing MBV, SUV_mean, and TBU with true values for various parameters, including bone lesion size, uptake ratio, and SUV cut-off level. Differences for MBV, SUV_mean, TBU, and bone scan index (BSI) were calculated to verify their utility in assessing bone metastases. Receiver-operating characteristic curve (ROC) analysis was performed to calculate the area under the curve (AUC) for each biomarker. MBV, SUV_mean, and TBU were affected by lesion size, uptake ratio, and SUV cut-off level; however, TBU demonstrated the most stable %Error. The TBU %Error was within 15% in spheres 17 mm or larger when the SUV cut-off level was 7, regardless of the uptake ratio. The ROC analyses revealed the AUCs of BSI (0.977) and TBU (0.968). Additionally, TBU was able to assess bone metastasis when BSI provided false-negative results, but TBU also provided false-positive results by degenerative changes. The synergy between TBU and BSI could potentially improve diagnostic accuracy.

Cancer Patient Experience in a Nuclear Medicine Department: Comparison Between Bone Scintigraphy and 18F-FDG PET/CT

Our objective was to assess the anxiety level in cancer patients undergoing nuclear medicine exams and to identify how professionals can improve patient experience. Methods: In total, 94 patients undergoing ^99mTc-hydroxymethylene diphosphonate (^99mTc-HDP) bone scintigraphy (BS) or ¹⁸F-FDG PET/CT completed 2 scan-experience questionnaires and the Spielberger State Anxiety Inventory (STAI-S) before the scan and after image acquisition. Results: Before the exam, the mean anxiety levels were higher for the ^99mTc-HDP BS group than for the ¹⁸F-FDG PET/CT group. After the exam, the opposite was true. Both groups experienced a reduction in anxiety after the scan (prescan score, 51.75 for ^99mTc-HDP BS and 44.67 for ¹⁸F-FDG PET/CT; postscan score, 36.70 for ^99mTc-HDP BS and 38.82 for ¹⁸F-FDG PET/CT). The greatest anxiety factor for the ^99mTc-HDP BS group was the duration of the exam (mean ± SD, 5.34 ± 2.08), whereas for the ¹⁸F-FDG PET/CT group it was the result (5.40 ± 1.80). Conclusion: Patients undergoing nuclear medicine exams in an oncologic context had significant anxiety levels before and after their scans. However, ^99mTc-HDP BS and ¹⁸F-FDG PET/CT had different triggers. It is of extreme importance that health-care professionals be aware of these peculiarities and adjust their procedures accordingly.

Computed Tomography (CT) Protocols Associated with Cardiac and Bone Single-Photon Emission Computed Tomography/CT (SPECT/CT) in Korea

PURPOSE

Single-photon emission computed tomography/computed tomography (SPECT/CT) is an advanced hybrid nuclear medicine technology that generates both functional and anatomical images in a single study. As utilization of SPECT/CT in Korea has been increasing, the purpose of this study was to survey its application of cardiac and skeletal SPECT/CT imaging for protocol optimization.

METHODS

We surveyed CT protocols established for cardiac and skeletal SPECT/CT. We searched the guidelines for the CT protocols for SPECT/CT and reviewed the literature recently published.

RESULTS

Among 36 hybrid SPECT scanners equipped with four or more multi-channel detector CTs (MDCTs), 18 scanners were used to perform cardiac studies at both very low current CT (30-80 mA; 11.1%) and ultra-low current CT (13-30 mA; 88.9%). Among the 33 canners, very low current (≤ 80 mA) CT or low current CT (80-130 mA) was used in 23.5%, and 41.8% for spine disorders, and in 36.4% or 30.3% for foot/ankle disorders, respectively. In the CT reconstructions, slice thickness of 5 mm for cardiac studies was most commonly used (94.4%); thinner slices (0.6-1.0 mm) for spine and foot/ankle studies were used in 24.2% and 45.5%, respectively. We also reviewed the international guidelines.

CONCLUSIONS

The results and current recommendations will be helpful for optimizing CT protocols for SPECT/CT. Optimization of SPECT/CT protocols will be required for generating the proper strategy for the specific lesions and clinical purpose.

A prospective intra-individual comparison of [68Ga]Ga-PSMA-11 PET/CT, [68Ga]Ga-NODAGAZOL PET/CT, and [99mTc]Tc-MDP bone scintigraphy for radionuclide imaging of prostate cancer skeletal metastases

PURPOSE

Prostate cancer (PCa) commonly metastasizes to the bones. There are several radionuclide techniques for imaging PCa skeletal metastases. We aimed to compare the lesion detection rate of [⁶⁸Ga]Ga-PSMA-11 PET/CT, [⁶⁸Ga]Ga-NODAGA-zoledronate ([⁶⁸Ga]Ga-NODAGA^ZOL) PET/CT, and [^99mTc]Tc-MDP bone scan in the assessment of bone metastases in patients with advanced PCa.

METHODS

We prospectively recruited two cohorts of patients (staging and re-staging cohorts) with advanced prostate cancer. The staging cohort was treatment-naïve PCa patients who showed skeletal metastases on bone scan. These patients were subsequently imaged with [⁶⁸Ga]Ga-PSMA-11 PET/CT and [⁶⁸Ga]Ga-NODAGA^ZOL PET/CT. Re-staging cohort was patients who were previously treated with PSMA-based radioligand therapy and were experiencing PSA progression. The re-staging cohort was imaged with [⁶⁸Ga]Ga-PSMA-11 PET/CT and [⁶⁸Ga]Ga-NODAGA^ZOL PET/CT. We performed a per-patient and per-lesion analysis of skeletal metastases in both cohorts and made a comparison between scan findings.

RESULTS

Eighteen patients were included with a median age of 68 years (range = 48-80) and a median Gleason score of 8. There were ten patients in the staging cohort with a median PSA of 119.26 ng/mL (range = 4.63-18,948.00) and eight patients in the re-staging cohort with a median PSA of 48.56 ng/mL (range = 6.51-3175.00). In the staging cohort, skeletal metastases detected by [⁶⁸Ga]Ga-PSMA-11 PET/CT, [⁶⁸Ga]Ga-NODAGA^ZOL PET/CT, and bone scan were 322, 288, and 261, respectively, p = 0.578. In the re-staging cohort, [⁶⁸Ga]Ga-PSMA-11 PET/CT and [⁶⁸Ga]Ga-NODAGA^ZOL PET/CT detected 152 and 191 skeletal metastases, respectively, p = 0.529. In two patients with negative [⁶⁸Ga]Ga-PSMA-11 PET/CT findings, [⁶⁸Ga]Ga-NODAGA^ZOL detected one skeletal metastasis in one patient and 12 skeletal metastases in the other.

CONCLUSION

In patients with advanced prostate cancer, [⁶⁸Ga]Ga-PSMA-11 PET/CT may detect more lesions than [⁶⁸Ga]Ga-NODAGA^ZOL PET/CT and [^99mTc]Tc-MDP bone scan for the staging of skeletal metastases. In patients who experience PSA progression on PSMA-based radioligand therapy, [⁶⁸Ga]Ga-NODAGA PET/CT is a more suitable imaging modality for the detection of skeletal lesions not expressing PSMA. In the setting of re-staging, [⁶⁸Ga]Ga-NODAGA^ZOL PET/CT may detect more lesions than [⁶⁸Ga]Ga-PSMA-11 PET/CT.

Diphosphonate single-photon emission computed tomography in cardiac transthyretin amyloidosis

BACKGROUND

Planar diphosphonate scintigraphy is an established diagnostic tool for amyloid transthyretin (ATTR) cardiomyopathy. Characterization of the amyloid burden up to the segmental level by single photon emission computed tomography (SPECT) has not been evaluated so far.

METHODS

Data from consecutive patients undergoing cardiac ^99mTc-hydroxymethylene diphosphonate (^99mTc-HMDP) SPECT and diagnosed with ATTR cardiomyopathy at a tertiary referral center from June 2016 to April 2019 were collected.

RESULTS

Thirty-eight patients were included (median age 81 years, 79% men, 92% with wild-type ATTR). In patients with Perugini score 1, the most intense diphosphonate regional uptake was found in septal segments, particularly in infero-septal segments. Among patients scoring 2, the amyloid burden in the septum became more significant, and extended to inferior and apical segments. Finally, patients scoring 3 displayed an intense and widespread tracer uptake. All patients with Perugini score 1 had LGE in at least one antero-septal, one infero-septal, and one infero-lateral segment. All patients with score 2 displayed LGE in infero-septal, inferior, and infero-lateral segments. LGE became extensive in patients scoring 3, with all patients having at least one LGE-positive segment in each region.

CONCLUSIONS

When assimilating different Perugini grades to evolutive stages of the disease, amyloid deposition seem to progress from the septum to the inferior wall and then to the other regions and from the basis to the apex. The potential of segmental analysis might be particularly relevant in patients with very limited cardiac uptake at planar scintigraphy (Perugini score 1).

Is sub-mSv CT for evaluation of non-specific findings in bone scintigraphy of oncological patients feasible?

Background

Hybrid SPECT/CT systems allow the shortening of lead time for investigation of cancer patients, since a complementary CT for radiological characterization of focally increased isotope uptake of unclear origin in bone scintigraphy can be performed simultaneously. The use of low-dose CT (sub-mSv CT) reduces radiation dose compared to standard-dose CT and facilitates the application of complementary CT.

Purpose

To test the feasibility of sub-mSv CT for the characterization of non-specific findings in the bone scintigraphy of oncological patients.

Material and Methods

Nineteen oncological patients with a total of 50 findings of unclear origin on bone scintigraphy which required further correlation with morphologic data were included in the study. Each patient underwent two CT scan series consecutively: one low-dose CT and one standard-dose CT. The CT studies were randomized and each finding was rated by four blinded experienced radiologists. A shift in ratings between standard-dose and low-dose images were assessed using the Stuart–Maxwell chi-squared test. Inter-observer agreement and intra-observer agreement was assessed using Light’s kappa and Cohen’s kappa, respectively.

Results

The mean effective dose of low-dose CT scans was 0.8 mSv compared to 4.2 mSv for the standard-dose CT scans. No statistically significant shift in ratings was observed ( P = 0.62). There was no statistically significant difference in the inter-observer agreements: the values for the standard-dose and low-dose groups were 0.68 (95% confidence interval [CI] 0.57–0.79) and 0.60 (95% CI 0.47–0.72), respectively.

Conclusion

These results indicate that sub-mSv CT for characterization of non-specific findings in bone scintigraphy of oncological patients is feasible.

Advances in Sensing Technologies for Monitoring of Bone Health

: Changing lifestyle and food habits are responsible for health problems, especially those related to bone in an aging population. Poor bone health has now become a serious matter of concern for many of us. In order to avoid serious consequences, the early prediction of symptoms and diagnosis of bone diseases have become the need of the hour. From this inspiration, the evolution of different bone health monitoring techniques and measurement methods practiced by researchers and healthcare companies has been discussed. This paper focuses on various types of bone diseases along with the modeling and remodeling phenomena of bones. The evolution of various diagnosis tests for bone health monitoring has been also discussed. Various types of bone turnover markers, their assessment techniques, and recent developments for the monitoring of biochemical markers to diagnose the bone conditions are highlighted. Then, the paper focuses on the potential assessment of the recent sensing techniques (physical sensors and biosensors) that are currently available for bone health monitoring. Considering the importance of electrochemical biosensors in terms of high sensitivity and reliability, specific attention has been given to the recent development of electrochemical biosensors and significance in real-time monitoring of bone health.

Prediction of Response to Tumor Necrosis Value-α Blocker Is Suggested by 18F-NaF SUVmax But Not by Quantitative Pharmacokinetic Analysis in Patients With Ankylosing Spondylitis

OBJECTIVE. We aimed to evaluate the pharmacokinetics and maximum standardized uptake value (SUV_max) of ¹⁸F-NaF PET/CT for assessment of disease activity and prediction of response in patients with ankylosing spondylitis (AS). MATERIALS AND METHODS. Twenty-seven patients (age, interquartile range, 30.25-49.75 years) with AS who were receiving a tumor necrosis factor-α (TNF-α) blocker were included. All patients underwent dynamic PET of the pelvis followed by whole-body PET/CT. Quantitative analysis of kinetic data of the sacroiliac joints (SIJs) was performed, and the SUV_max of the SIJs and SUV_max of the spine were calculated. Clinical indexes related to AS disease activity (serum C-reactive protein level, Bath ankylosing spondylitis disease activity index [ BASDAI], and Bath ankylosing spondylitis functional index) were evaluated. Clinical response was defined as an improvement from the initial BASDAI score of 50% or more (BASDAI 50) within 2 years after baseline ¹⁸F-NaF PET/CT. RESULTS. The BASDAI score at ¹⁸F-NaF PET/CT was significantly different between the responders and nonresponders: ¹⁸F-NaF uptake at the spine was significantly higher in the responders than in the nonresponders. Only SUV_max of the spine had a significant positive correlation with BASDAI score at PET/CT (r = 0.38, p = 0.048). The BASDAI score at PET/CT (odds ratio [OR], 35.32; 95% CI, 2.09-57.84; p = 0.014) and SUV_max of the spine (OR, 14.69; 95% CI, 0.79-27.27; p = 0.027) were significantly associated with BASDAI 50 response prediction. CONCLUSION. The results of our study suggest that the SUV_max of the spine on whole-body ¹⁸F-NaF PET/CT is a reliable and noninvasive biomarker for predicting therapeutic response to TNF-α blocker and shows better performance for predicting response than quantitative pharmacokinetic parameters. Fluorine-18-labeled NaF PET/CT showed axial bone lesions with bone formation and can be used as a monitoring tool in patients with AS receiving anti-TNF-α drugs. However, these results need to be validated in a larger cohort.

Added value of 68Ga-PSMA PET/CT for the detection of bone metastases in patients with newly diagnosed prostate cancer and a previous 99mTc bone scintigraphy

Purpose

To investigate the added value and diagnostic accuracy of ⁶⁸Ga-PSMA PET/CT versus bone scintigraphy (BS) for bone metastasis detection at the primary staging of prostate cancer (PCa).

Methods

Inclusion criteria involved consecutive patients with newly diagnosed intermediate- to high-risk PCa, who had undergone BS, mostly with supplementary SPECT/low-dose CT, and ⁶⁸Ga-PSMA-11 PET/CT within less than 3 months without therapy initiation between the two investigations. BS was evaluated according to clinical routine and reported as no bone metastases (M0), bone metastases (M1), or equivocal (Me). The ⁶⁸Ga-PSMA-11 PET/CT was blindly evaluated by three specialists as M0, M1, or Me at the patient level. Sensitivity analyses were conducted using a “best valuable comparator” using all available imaging and clinical follow-up as a reference.

Results

In total, 112 patients were included; ⁶⁸Ga-PSMA-11 PET/CT showed a sensitivity of 1.00, specificity of 0.93–0.96, positive predictive value of 0.74–0.81, and negative predictive value of 1.00. ⁶⁸Ga-PSMA-11 PET/CT revealed bone metastases in 8 of 81 patients with M0 disease according to BS. ⁶⁸Ga-PSMA-11 PET/CT confirmed the presence of bone metastases in all patients (n = 9) with M1 disease according to BS. In patients with Me by BS, ⁶⁸Ga-PSMA PET/CT provided a definite result in 20 of 22 patients. ⁶⁸Ga-PSMA-11 PET/CT resulted in a false-positive answer in four patients with solitary rib lesions.

Conclusion

⁶⁸Ga-PSMA-11 PET/CT revealed bone metastases in 10% of patients without bone metastases on BS and in 36% patients with indeterminate BS. However, solitary PSMA-avid lesions in the ribs should be interpreted cautiously as they may represent false-positive findings.

Non-hematologic diagnosis of systemic mastocytosis: Collaboration of radiology and pathology

Systemic mastocytosis (SM) is a hematologic disease with a wide range of clinical courses ranging from an indolent condition with normal life expectancy to exceedingly aggressive disorder with a poor prognosis. The symptoms and signs of SM result from the release of mast cell mediators with heterogeneous functions, and/or organ damage from neoplastic mast cell infiltration, or both. Diagnostic criteria for SM are well-defined by the World Health Organization (WHO). However, the diagnosis of SM can be difficult when especially it is not in the differential diagnosis. Routinely used radiologic techniques (e.g., X-ray, ultrasound, CT scans can show findings such as lytic-, sclerotic- or mixed-bone lesions, splenomegaly, hepatomegaly, retroperitoneal or periportal mesenteric lymphadenopathy, and omental thickening). It is essential to emphasize that the constellation of these radiologic findings should strongly concern of SM, especially in patients who also have a skin rash, allergic reactions, gastrointestinal tract symptoms (lasting, intermittent nausea, diarrhea), paroxysmal tachycardias, unexplained weight loss, persistent bone pain, cytopenias, liver dysfunction, eosinophilia. These findings, even coincidentally noted, will likely lead to a tissue biopsy, which reveals diagnosis (as we discussed and illustrated some tissue biopsies here). Moreover, the role of MRI and new techniques such as [18-fluorodeoxyglucose positron emission computed tomography, fibroscan] in the diagnosis of SM have been discussed. Furthermore, we reviewed the use of radiologic methods to evaluate treatment response and prognostication of SM..

Gastric 99mTc-Methylene Diphosphonate Accumulation in a Patient With Primary Upper Gastrointestinal Tract Melanoma

Unexpected extraosseous uptake is common on Tc-methylene diphosphonate bone scintigraphy, but accumulation by primary upper gastrointestinal tract malignant melanoma is rarely reported. The present case is a 58-year-old woman with a 10-day history of diffuse bone pain and weakness. Her bone scintigraphy showed unexpected diffuse gastric tracer uptake. Subsequent gastroscopy revealed a number of hyperpigmented lesions in the stomach and duodenal bulb. Malignant melanoma was confirmed by histopathology and immunohistochemistry. Because extensive physical examination failed to identify any other site of ocular and cutaneous melanoma, a diagnosis of primary upper gastrointestinal tract malignant melanoma was established.

[99mTc]-labelled interleukin-8 as a diagnostic tool compared to [18F]FDG and CT in an experimental porcine osteomyelitis model

Osteomyelitis (OM) is an important cause of morbidity and sometimes mortality in children and adults. Long-term complications can be reduced when treatment is initiated in an early phase. The diagnostic gold standard is microbial examination of a biopsy and current non-invasive imaging methods are not always optimal. [¹¹¹In]-leukocyte scintigraphy is recommended for peripheral OM, but is time-consuming and not recommended in children. [¹⁸F]FDG PET/CT is recommended for vertebral OM in adults, but has the disadvantage of false positive findings and a relatively high radiation exposure; the latter is a problem in children. [^99mTc]-based tracers are consequently preferred in children. We, therefore, aimed to find a [^99mTc]-marked tracer with high specificity and sensitivity for early detection of OM. Suppurating inflammatory lesions like OM caused by Staphylococcus aureus (S. aureus) will attract large numbers of neutrophils and macrophages. A preliminary study has shown that [^99m Tc]-labelled IL8 may be a possible candidate for imaging of peripheral OM. We investigated [^99mTc]IL8 scintigraphy in a juvenile pig model of peripheral OM and compared it with [¹⁸F]FDG PET/CT. The pigs were experimentally inoculated with S. aureus to induce OM and scanned one week later. We also examined leukocyte count, serum CRP and IL8, as well as performed histopathological and microbiological investigations. [ ^99m Tc]IL8 was easily and relatively quickly prepared and was shown to be suitable for visualization of OM lesions in peripheral bones detecting 70% compared to a 100% sensitivity of [¹⁸F]FDG PET/CT. [ ^99m Tc]IL8 is a promising candidate for detection of OM in peripheral bones in children.

A Deep-Learning Approach for Diagnosis of Metastatic Breast Cancer in Bones from Whole-Body Scans

(1) Background: Bone metastasis is one of the most frequent diseases in breast, lung and prostate cancer; bone scintigraphy is the primary imaging method of screening that offers the highest sensitivity (95%) regarding metastases. To address the considerable problem of bone metastasis diagnosis, focused on breast cancer patients, artificial intelligence methods devoted to deep-learning algorithms for medical image analysis are investigated in this research work; (2) Methods: Deep learning is a powerful algorithm for automatic classification and diagnosis of medical images whereas its implementation is achieved by the use of convolutional neural networks (CNNs). The purpose of this study is to build a robust CNN model that will be able to classify images of whole-body scans in patients suffering from breast cancer, depending on whether or not they are infected by metastasis of breast cancer; (3) Results: A robust CNN architecture is selected based on CNN exploration performance for bone metastasis diagnosis using whole-body scan images, achieving a high classification accuracy of 92.50%. The best-performing CNN method is compared with other popular and well-known CNN architectures for medical imaging like ResNet50, VGG16, MobileNet, and DenseNet, reported in the literature, providing superior classification accuracy; and (4) Conclusions: Prediction results show the efficacy of the proposed deep learning approach in bone metastasis diagnosis for breast cancer patients in nuclear medicine.

Bone Scintigraphy After a Negative Radiological Skeletal Survey Improves the Detection Rate of Inflicted Skeletal Injury in Children

Background: Timely diagnosis of child physical abuse is of paramount importance. The added value of bone scintigraphy (BS) after a negative radiological skeletal survey (RSS) in children with suspected physical abuse has never been evaluated. Objective: The objective of this study was to assess the extent to which BS could improve the detection rate of skeletal injury in children with suspected physical abuse with an initial negative RSS. Methods: We used discharge codes to retrospectively identify children evaluated for suspected physical abuse in a university hospital (Nantes, France). We included all consecutive children younger than 3 years old who underwent both RSS and BS, with an interval of ≤96 h between tests, from 2013 to 2019. BS and RSS results were interpreted independently during the study period. We specifically analyzed BS results for children with a negative RSS to assess the value of BS as an add-on test. Results: Among the 268 children ≤3 years old with suspected physical abuse who underwent RSS, 140 (52%) also underwent BS within 96 h and were included in the analysis. The median age was 6 months old (interquartile range: 3-8). The detection rate of ≥1 skeletal injury with RSS alone was 49% (n = 69/140, 95% CI: 41-58%) vs. 58% (n = 81/140, 50-66%) with RSS followed by add-on BS, for an absolute increase in the detection rate of 9% points (95% CI: 4-14%). The number of children with a negative RSS who would need to undergo BS to detect one additional child with ≥1 skeletal injury was 6 (95% CI: 4-11). Conclusion: In young children with suspected physical abuse with a negative RSS, add-on BS would allow for a clinically significant improvement in the detection rate of skeletal injuries for a limited number of BS procedures required. Prospective multicenter studies are needed to confirm these findings.

[Evaluation of Post-reconstruction Filtering in Resolution Recovery Reconstruction for Bone SPECT Imaging]

PURPOSE

The aim of this study was to clarify the optimal post-reconstruction filtering type in the three- dimensional ordered subset expectation maximization (3D-OSEM) method for bone single photon emission computed tomography (SPECT) from image quality and quantitative values.

METHOD

We scanned a National Electrical Manufactures Association's body phantom for bone SPECT filled with radioactive solution of ^99mTc whose radioactivity concentration was accurately measured. The SPECT images were created using the 3D-OSEM method. Post-reconstruction filtering was performed using a Butterworth filter (BW), a Gaussian filter (GA), and a Hanning filter (HA) with various parameters. The image quality was evaluated by the normalized mean-squared error (NMSE) value and % of contrast-to-noise ratio (QNR₁₇). The image quality was evaluated by the error values between the measured radioactivity concentration and the true radioactivity concentration in the BG region and insert sphere.

RESULTS

The minimum NMSE values were 0.034 (BW), 0.036 (GA), and 0.035 (HA), and there was no difference depending on the filter type. The values of QNR₁₇ were 2.5 (BW), 2.6 (GA), and 2.6 (HA), and there was no difference depending on the filter type. The BG region was greatly affected by parameter changes in GA but less by those in BW and HA. The error values of the 37 mm insert sphere were 18.0% (BW), 28.2% (GA), and 26.2% (HA), and BW showed the lowest value.

CONCLUSION

Our results suggest that the post-reconstruction filtering type used in the 3D-OSEM method was BW from the image quality and quantitative values.

Positive Myocardial Uptake of Bone Scintigraphic Agents Associated with Cardiac Amyloidosis: Frequency of Positive Uptake Data Based on Daily Clinical Practice

Objective: The bone scan plays an important role for detecting number of conditions relating to bones, including: bone cancer or bone metastasis, bone inflammation. Extraosseous uptake, in particular, myocardial uptake, was observed in some patients examined with the bone scans. Positive uptake of ^99mTc-labeled bone radiotracers is associated with cardiac amyloidosis. However, the frequency and cause of positive cardiac ^99mTc-MDP uptake have not been fully studied. In this regard, the aim of this study was to assess the frequency and characteristics of patients with high myocardi-al uptake of bone scintigraphy in daily clinical practice setting. Methods: We retrospectively analyzed 4180 bone scintigraphies performed in daily clinical practice during 7-years period. The intensity of the myocardial uptake was graded based on a visual scale ranging from 0 to 3 points. Score 0 indicates the absence of uptake. Score 1 defined uptake less than that of bone (referred to as the adjacent rib). Uptake similar to that of bone was classified score 2. Score 3 was defined as uptake greater than that of reference bone. Positive myocardial uptake included a visual score 2 or 3. Result: Positive ^99mTc-MDP myocardial uptake occurred in 12 patients among 4180 patients (0.3%). 7 of 12 positive scan patients were consistent with amyloidosis confirmed by biopsy. In these patients, the mean age was 75.6 ± 5.2 years old. Ten cases showed biventricular uptake and 2 showed LV uptake only. Conclusion: Positive cardiac uptake of bone scintigraphic agents was present in 0.3% of bone scintigraphies in a clinical practice setting. This may be a sign of cardiac amyloidosis involvement which may give the presence of extraosseous bone tracer uptake its own importance and a new role.

A retrospective study of bone scintigraphy in the follow-up of patients with synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome: is it useful to repeat bone scintigraphy for disease assessment?

OBJECTIVES

To investigate the value of repeated bone scintigraphy in the follow-up of patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and to characterize the changing pattern of osteoarticular lesions revealed by bone scintigraphy.

METHOD

Twenty-four patients with SAPHO syndrome who had repetitively undergone bone scintigraphy and tests of inflammatory markers (erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP)) were included in this retrospective study. The change in accumulation number was recorded as the difference in the number of accumulation sites between consecutive bone scintigraphy. The visual analog scale (VAS) for pain and medications prescribed were also reviewed. The relationships of the change in accumulation number with medication prescribed and change in ESR or CRP were analyzed.

RESULTS

Twenty-four and 23 patients had follow-up tests of ESR and CRP, from which 30 and 28 follow-up data were obtained, containing the corresponding changes in ESR and CRP, respectively. A decrease in total accumulation number observed by bone scintigraphy was rarely observed, while decreases in ESR, CRP, and VAS were predominant. The accumulation number had significantly increased over time (follow-up with ESR: r = 0.389, p = 0.034; follow-up with CRP: r = 0.438, p = 0.020), in accordance with an "imprinting" pattern, while the inflammatory markers and VAS for pain predominantly decreased. There was no significant association between the change in accumulation number (local/total) and the change in ESR or CRP values (p > 0.05) or medications used for SAPHO (p > 0.05).

CONCLUSIONS

This retrospective cohort study of 24 SAPHO patients demonstrated an "imprinting" pattern on bone scintigraphy, without a correlation to the decrease in inflammatory markers, patient disease assessment, or treatment type. Thus, repeated bone scintigraphy did not contribute an additional clinical value for the follow-up of patients with SAPHO.Key Points• In a cohort of 24 SAPHO patients, repeated bone scintigraphy revealed a continuous increase in tracer accumulation number, indicating an "imprinting" pattern.• The change in tracer accumulation number, defined as the difference in the number of accumulation sites between consecutive bone scintigraphy measurements, was inconsistent with the change in ESR, CRP, or VAS for pain.• The medications prescribed for SAPHO did not seem to contribute to a decrease in accumulation number.• Repeated bone scintigraphy did not seem to be useful for the assessment of disease activity in patients with SAPHO.

Role of Baseline and Post-Therapy 18F-FDG PET in the Prognostic Stratification of Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients Treated with Radium-223

Radium-223 dichloride (Ra223) represents the unique bone-directed treatment option that shows an improvement in overall survival (OS) in metastatic castrate resistant prostate cancer (mCRPC). However, there is an urgent need for the identification of reliable biomarkers to non-invasively determine its efficacy (possibly improving patients’ selection or identifying responders’ after therapy completion). 18F-Fluorodeoxyglucose (FDG)-avidity is low in naïve prostate cancer, but it is enhanced in advanced and chemotherapy-refractory mCRPC, providing prognostic insights. Moreover, this tool showed high potential for the evaluation of response in cancer patients with bone involvement. For these reasons, FDG Positron Emission Tomography (FDG-PET) might represent an effective tool that is able to provide prognostic stratification (improving patients selection) at baseline and assessing the treatment response to Ra223. We conducted a retrospective analysis of 28 mCRPC patients that were treated with Ra223 and submitted to bone scan and FDG-PET/CT for prognostic purposes at baseline and within two months after therapy completion. The following parameters were measured: number of bone lesions at bone scan, SUVmax of the hottest bone lesion, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). In patients who underwent post-therapy 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT), (20/28), PET Response Criteria in Solid Tumors (PERCIST), and European Organization for Research and Treatment of Cancer (EORTC) criteria were applied to evaluate the metabolic treatment response. The difference between end of therapy and baseline values was also calculated for Metabolic Tumor Volume (MTV), TLG, prostate-specific antigen (PSA), alkaline phosphatase (AP), and lactate dehydrogenase (LDH) (termed deltaMTV, deltaTLG, deltaPSA, deltaAP and deltaLDH, respectively). Predictive power of baseline and post-therapy PET- and biochemical-derived parameters on OS were assessed by Kaplan–Meier, univariate and multivariate analyses. At baseline, PSA, LDH, and MTV significantly predicted OS. However, MTV (but not PSA nor LDH) was able to identify a subgroup of patients with worse prognosis, even after adjusting for the number of lesions at bone scan (which, in turn, was not an independent predictor of OS). After therapy, PERCIST criteria were able to capture the response to Ra223 by demonstrating longer OS in patients with partial metabolic response. Moreover, the biochemical parameters were outperformed by PERCIST in the post-treatment setting, as their variation after therapy was not informative on long term OS. The present study supports the role of FDG-PET as a tool for patient’s selection and response assessment in mCRPC patients undergoing Ra223 administration.

Scintigraphic load of bone disease evaluated by DASciS software as a survival predictor in metastatic castration-resistant prostate cancer patients candidates to 223RaCl treatment

Background

Aim of our study was to assess the load of bone disease at starting and during Ra-223 treatment as an overall survival (OS) predictor in metastatic castration-resistant prostate cancer (mCRPC) patients. Bone scan index (BSI) is defined as the percentage of total amount of bone metastasis on whole-body scintigraphic images. We present a specific software (DASciS) developed by an engineering team of “Sapienza” University of Rome for BSI calculation.

Patients and methods

127 mCRPC patients bone scan images were processed with DASciS software, and BSI was tested as OS predictor.

Results

546 bone scans were analyzed revealing that the extension of disease is a predictor of OS (0–3% = 28 months of median survival (MoMS]; 3%–5% = 11 MoMS, > 5% = 5 MoMS). BSI has been analyzed as a single parameter for OS, determining an 88% AUC. Moreover, the composition between the BSI and the 3-PS (3-variable prognostic score) determines a remarkable improvement of the AUC (91%), defining these two parameters as the best OS predictors.

Conclusions

This study suggests that OS is inversely correlated with the load of bone disease in mCRPC Ra-223-treated subjects. DASciS software appears a promising tool in identifying mCRPC patients that more likely take advantage from Ra-223 treatment. BSI is proposed as a predictive variable for OS and included to a multidimensional clinical evaluation permits to approach the patients’ enrollment in a rational way, allowing to enhance the treatment effectiveness together with cost optimization.

A Nordic survey of CT doses in hybrid PET/CT and SPECT/CT examinations

Background

Computed tomography (CT) scans are routinely performed in positron emission tomography (PET) and single photon emission computed tomography (SPECT) examinations globally, yet few surveys have been conducted to gather national diagnostic reference level (NDRL) data for CT radiation doses in positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/computed tomography (SPECT/CT). In this first Nordic-wide study of CT doses in hybrid imaging, Nordic NDRL CT doses are suggested for PET/CT and SPECT/CT examinations specific to the clinical purpose of CT, and the scope for optimisation is evaluated. Data on hybrid imaging CT exposures and clinical purpose of CT were gathered for 5 PET/CT and 8 SPECT/CT examinations via designed booklet. For each included dataset for a given facility and scanner type, the computed tomography dose index by volume (CTDI_vol) and dose length product (DLP) was interpolated for a 75-kg person (referred to as CTDI_vol,75kg and DLP_75kg). Suggested NDRL (75th percentile) and achievable doses (50th percentile) were determined for CTDI_vol,75kg and DLP_75kg according to clinical purpose of CT. Differences in maximum and minimum doses (derived for a 75-kg patient) between facilities were also calculated for each examination and clinical purpose.

Results

Data were processed from 83 scanners from 43 facilities. Data were sufficient to suggest Nordic NDRL CT doses for the following: PET/CT oncology (localisation/characterisation, 15 systems); infection/inflammation (localisation/characterisation, 13 systems); brain (attenuation correction (AC) only, 11 systems); cardiac PET/CT and SPECT/CT (AC only, 30 systems); SPECT/CT lung (localisation/characterisation, 12 systems); bone (localisation/characterisation, 30 systems); and parathyroid (localisation/characterisation, 13 systems). Great variations in dose were seen for all aforementioned examinations. Greatest differences in DLP_75kg for each examination, specific to clinical purpose, were as follows: SPECT/CT lung AC only (27.4); PET/CT and SPECT/CT cardiac AC only (19.6); infection/inflammation AC only (18.1); PET/CT brain localisation/characterisation (16.8); SPECT/CT bone localisation/characterisation (10.0); PET/CT oncology AC only (9.0); and SPECT/CT parathyroid localisation/characterisation (7.8).

Conclusions

Suggested Nordic NDRL CT doses are presented according to clinical purpose of CT for PET/CT oncology, infection/inflammation, brain, PET/CT and SPECT/CT cardiac, and SPECT/CT lung, bone, and parathyroid. The large variation in doses suggests great scope for optimisation in all 8 examinations.

Automated measurement of bone scan index from a whole-body bone scintigram

Purpose

We propose a deep learning-based image interpretation system for skeleton segmentation and extraction of hot spots of bone metastatic lesion from a whole-body bone scintigram followed by automated measurement of a bone scan index (BSI), which will be clinically useful.

Methods

The proposed system employs butterfly-type networks (BtrflyNets) for skeleton segmentation and extraction of hot spots of bone metastatic lesions, in which a pair of anterior and posterior images are processed simultaneously. BSI is then measured using the segmented bones and extracted hot spots. To further improve the networks, deep supervision (DSV) and residual learning technologies were introduced.

Results

We evaluated the performance of the proposed system using 246 bone scintigrams of prostate cancer in terms of accuracy of skeleton segmentation, hot spot extraction, and BSI measurement, as well as computational cost. In a threefold cross-validation experiment, the best performance was achieved by BtrflyNet with DSV for skeleton segmentation and BtrflyNet with residual blocks. The cross-correlation between the measured and true BSI was 0.9337, and the computational time for a case was 112.0 s.

Conclusion

We proposed a deep learning-based BSI measurement system for a whole-body bone scintigram and proved its effectiveness by threefold cross-validation study using 246 whole-body bone scintigrams. The automatically measured BSI and computational time for a case are deemed clinically acceptable and reliable.

The Effect of an Asymmetric Energy Window on Bone Scintigraphy Image Quality

Bone scintigraphy is one of the most common nuclear medicine tests. Previous work investigated the effectiveness of an asymmetric window (ASW) for planar bone scintigraphy using simulation and phantom data. Phantom studies concluded that the ASW improved both the resolution and the contrast-to-noise ratio when imaging objects with high scatter. The aim of this study was to confirm this improvement increased image quality in patients. This study also investigated whether the differences between a symmetric window (SW) and an ASW depended on body mass index. Methods: Fifty-eight patients had 2 scans: a standard scan using an SW of 140 keV ± 10% and a scan using an ASW of 140 keV + 10% and - 7.5%. Three readers independently compared the 2 image sets and scored them using a 5-score scale (ranging from 1 = ASW better [clinically important] to 5 = SW better [clinically important]). Scores from all radiologists were pooled and analyzed statistically. A P value of less than 0.05 was considered statistically significant. Results: In 93 cases (53%), the readers scored the ASW images better than the SW images. In 5 cases (3%), the ASW images were preferred, with the difference considered clinically important; there were no cases in which the SW was similarly preferred. For the sign test, we determined whether the total of 93 scores of 1 or 2 (ASW preferred) was significantly different from the 15 scores of 4 or 5 (SW preferred). The P value was less than 0.00001, demonstrating that the difference was significant. Conclusion: In patients undergoing bone scintigraphy, ASW provided an improvement in image quality that in some cases was judged clinically important.

18F-Fluoromethylcholine-positron emission tomography/computed tomography for diagnosing bone and lymph node metastases in patients with intermediate- or high-risk prostate cancer

Background

The use of molecular imaging in staging of prostate cancer (PC) is debated. In patients with newly diagnosed PC we investigated the diagnostic value of ¹⁸F-flouromethylcholine positron emission tomography/computed tomography (¹⁸F-FCH-PET/CT) for the detection of bone and lymph node metastases compared to whole-body bone scintigraphy (WBS) with technetium-99-methylene diphosphonate (^99mTc-MDP) and results of extended pelvic lymph node dissection, respectively.

Materials and methods

Between January 2013 and April 2016, 143 patients, aged 49-83, mean 69, years with newly diagnosed PC and disease characteristics necessitating WBS underwent both WBS and ¹⁸F-FCH-PET/CT using magnetic resonance imaging as standard. Eighty of these patients underwent pelvic lymph node dissection as part of radical prostatectomy or prior to external beam radiation and in these results of ¹⁸F-FCH-PET/CT were compared to histologic findings.

Results

Bone metastases were detected in 8/143 patients and sensitivity and specificity of WBS were 37.5% and 85.2% versus 100.0% and 96.3% with ¹⁸F-FCH-PET/CT, P=0.63 and 0.002, respectively. Histologically confirmed metastases to regional lymph nodes were found in 25/80 patients. Suspicious choline uptake on PET/CT in pelvic lymph nodes was found in 35 patients. Sensitivity, specificity, PPV, NPV and accuracy of ¹⁸F-FCH-PET/CT in detection of lymph node metastases were 62.5%, 69.6%, 46.9%, 81.3% and 67.5%, respectively.

Conclusions

Findings in this study suggested that ¹⁸F-FCH-PET/CT is a more sensitive and specific method for detection of bone metastases from PC than WBS and could potentially reduce the need for confirmatory imaging if used instead of WBS. However, ¹⁸F-FCH-PET/CT performs sub-optimally in pre-operative staging of lymph node metastases in patients undergoing extended pelvic lymph node dissection.

Two decades of SPECT/CT - the coming of age of a technology: An updated review of literature evidence

PURPOSE

Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) was introduced as a hybrid SPECT/CT imaging modality two decades ago. The main advantage of SPECT/CT is the increased specificity achieved through a more precise localization and characterization of functional findings. The improved diagnostic accuracy is also associated with greater diagnostic confidence and better inter-specialty communication.

METHODS

This review presents a critical assessment of the relevant literature published so far on the role of SPECT/CT in a variety of clinical conditions. It also includes an update on the established evidence demonstrating both the advantages and limitations of this modality.

CONCLUSIONS

For the majority of applications, SPECT/CT should be a routine imaging technique, fully integrated into the clinical decision-making process, including oncology, endocrinology, orthopaedics, paediatrics, and cardiology. Large-scale prospective studies are lacking, however, on the use of SPECT/CT in certain clinical domains such as neurology and lung disorders. The review also presents data on the complementary role of SPECT/CT with other imaging modalities and a comparative analysis, where available.

U.S. PET/CT and Gamma Camera Diagnostic Reference Levels and Achievable Administered Activities for Noncardiac Nuclear Medicine Studies

Existing surveys of radiopharmaceutical doses for U.S. nuclear medicine laboratories are of limited scope and size. Dose data are important because they can be used to benchmark individual laboratories, understand geographic variations in practice, and provide source data for societal guidelines and appropriateness criteria. Diagnostic reference levels (DRLs) and achievable administered activities (AAAs) for 13 noncardiac adult gamma camera and PET/CT examinations were derived retrospectively from American College of Radiology accreditation data (January 1, 2015, to December 31, 2017). The calculated DRL and AAA are consistent with previously published surveys. The distributions of radiopharmaceutical doses across facilities are in general consistent but show variation within a particular examination. Analysis of dose distribution suggests this variation results from differences in clinical protocols, educational gaps, and/or equipment factors. The AAA for the surveyed facilities exceeds dose ranges proposed in societal practice guidelines for several common nuclear medicine studies. Compared with similar surveys from Europe and Japan, geographic variation is observed, with some doses greater and others lower than used in the United States. Overall, radiopharmaceutical dose variation within the United States and internationally, and deviation from societal guidelines, imply that these dose-related benchmarks may be used to further standardize and improve clinical practice.

Beyond the bones and joints: a review of ligamentous injuries of the foot and ankle on 99mTc-MDP-SPECT/CT

^99mTc-MDP-single photon emission computed tomography (SPECT)/CT has established itself as a useful modality in the assessment of the painful foot and ankle, owing to its ability to depict anatomical and functional information simultaneously. Despite its growing popularity, much of the literature describing the utility of ^99mTc-MDP-SPECT/CT of the foot and ankle is limited to osseous and articular pathology, with descriptions of ligamentous pathology limited to just a handful of cases. Though assessment of soft tissues using a combination of bone tracer and CT is limited, with a sound understanding of the regional anatomy, it is certainly within the scope of ^99mTc-MDP-SPECT/CT to accurately identify ligamentous injuries based on focal tracer uptake patterns and suspected ligamentous injuries should be reported as such. This article provides a case-based pictorial review of the ^99mTc-MDP-SPECT/CT appearances of the various ligamentous injuries of the foot and ankle with case examples and MRI correlation where available, most of which have yet to be described. The typical patterns of bone tracer uptake and associated CT abnormalities that may be observed are discussed.

Reduced bone activity in the native compartments after medial mobile-bearing unicompartmental knee arthroplasty. A prospective SPECT/CT study

AIMS

Altered alignment and biomechanics are thought to contribute to the progression of osteoarthritis (OA) in the native compartments after medial unicompartmental knee arthroplasty (UKA). The aim of this study was to evaluate the bone activity and remodelling in the lateral tibiofemoral and patellofemoral compartment after medial mobile-bearing UKA.

PATIENTS AND METHODS

In total, 24 patients (nine female, 15 male) with 25 medial Oxford UKAs (13 left, 12 right) were prospectively followed with sequential 99mTc-hydroxymethane diphosphonate single photon emission CT (SPECT)/CT preoperatively and at one and two years postoperatively, along with standard radiographs and clinical outcome scores. The mean patient age was 62 years (40 to 78) and the mean body mass index (BMI) was 29.7 kg/m2 (23.6 to 42.2). Mean osteoblastic activity was evaluated using a tracer localization scheme with volumes of interest (VOIs). Normalized mean tracer values were calculated as the ratio between the mean tracer activity in a VOI and background activity in the femoral diaphysis.

RESULTS

Significant reduction of normalized tracer activity was observed one year postoperatively in tibial and femoral VOIs adjacent to the joint line in the lateral compartment. Patellar VOIs and remaining femoral VOIs demonstrated a significant, diminished normalized tracer activity at final follow-up.

CONCLUSION

The osteoblastic bone activity in the native compartments decreased significantly after treatment of medial end-stage OA with a UKA, implying reduced stress to the subchondral bone in the retained compartments after a UKA. Cite this article: Bone Joint J 2019;101-B:915-921.

Denoising of Scintillation Camera Images Using a Deep Convolutional Neural Network: A Monte Carlo Simulation Approach

Scintillation camera images contain a large amount of Poisson noise. We have investigated whether noise can be removed in whole-body bone scans using convolutional neural networks (CNNs) trained with sets of noisy and noiseless images obtained by Monte Carlo simulation. Methods: Three CNNs were generated using 3 different sets of training images: simulated bone scan images, images of a cylindric phantom with hot and cold spots, and a mix of the first two. Each training set consisted of 40,000 noiseless and noisy image pairs. The CNNs were evaluated with simulated images of a cylindric phantom and simulated bone scan images. The mean squared error between filtered and true images was used as difference metric, and the coefficient of variation was used to estimate noise reduction. The CNNs were compared with gaussian and median filters. A clinical evaluation was performed in which the ability to detect metastases for CNN- and gaussian-filtered bone scans with half the number of counts was compared with standard bone scans. Results: The best CNN reduced the coefficient of variation by, on average, 92%, and the best standard filter reduced the coefficient of variation by 88%. The best CNN gave a mean squared error that was on average 68% and 20% better than the best standard filters, for the cylindric and bone scan images, respectively. The best CNNs for the cylindric phantom and bone scans were the dedicated CNNs. No significant differences in the ability to detect metastases were found between standard, CNN-, and gaussian-filtered bone scans. Conclusion: Noise can be removed efficiently regardless of noise level with little or no resolution loss. The CNN filter enables reducing the scanning time by half and still obtaining good accuracy for bone metastasis assessment.

Does quantification have a role to play in the future of bone SPECT?

Routinely, there is a visual basis to nuclear medicine reporting: a reporter subjectively places a patient's condition into one of multiple discrete classes based on what they see. The addition of a quantitative result, such as a standardised uptake value (SUV), would provide a numerical insight into the nature of uptake, delivering greater objectivity, and perhaps improved patient management.For bone scintigraphy in particular quantification could increase the accuracy of diagnosis by helping to differentiate normal from abnormal uptake. Access to quantitative data might also enhance our ability to characterise lesions, stratify and monitor patients' conditions, and perform reliable dosimetry for radionuclide therapies. But is there enough evidence to suggest that we, as a community, should be making more effort to implement quantitative bone SPECT in routine clinical practice?We carried out multiple queries through the PubMed search engine to facilitate a cross-sectional review of the current status of bone SPECT quantification. Highly cited papers were assessed in more focus to scrutinise their conclusions.An increasing number of authors are reporting findings in terms of metrics such as SUVmax. Although interest in the field in general remains high, the rate of clinical implementation of quantitative bone SPECT remains slow and there is a significant amount of validation required before we get carried away.

Prostate-specific antigen and risk of bone metastases in west Africans with prostate cancer

We aimed to assess the relationship between bone scintigraphy findings and prostate-specific antigen (PSA) and Gleason score in a group of treatment naïve West Africans with prostate cancer. The age, PSA, and Gleason scores of 363 patients with prostate cancer were collected. Patients were risk stratified using the D'Amico criteria. Logistic regression was performed to assess the relationship between bone scan results and PSA and Gleason score. Receiver operating characteristics (ROC) analysis was used to determine the diagnostic reliability of the bone scan findings. Ninety of the 96 patients with metastases had high risk, and only 6 had low-to-intermediate risk disease (P = 0.0001). PSA (odds ratio [OR] 2.4 [95% confidence interval [CI] 1.5-3.8], P = 0.001) and GS (OR 2.2 [95% CI 1.5-3.1], P = 0.001) were independently predictive of the presence of metastases. ROC analysis revealed that PSA predicted the presence of metastases with an area under the curve of 0.72, and using a cut-off value of ≥20 predicted metastases with a sensitivity of 86.5% and specificity of 41.2%. A Gleason score of ≥7 had an 89.6% sensitivity and 34.8% specificity for bone metastases. Using a Gleason cutoff of ≥8, the sensitivity and specificity for predicting bone metastases were 54.2% and 71.5%, respectively. The area under the Gleason score ROC curve was 0.68. PSA and Gleason score are independent predictors of the presence of bone metastases in West Africans with prostate cancer.

Bone scan index as metastatic bone disease quantifier and predictor of radium-223-dichloride biochemical response

OBJECTIVES

This work aims to assess whether the biochemical response of radium-223-dichloride treatment can be predicted based on the pretherapy bone scan, and consequently if bone scan index (BSI) and maximum lesion intensity have a place as alternatives or as complements to extent of bone disease (EOBD) scoring in predicting biochemical response to treatment. Many cases of advanced prostate cancer have evidence of bone metastasis. Accurate EOBD quantification could help predict the response to radium-223-dichloride therapy. Current EOBD score is simple to use but does not consider size, intensity or localisation of lesion BSI might be more suitable for stratification of bone metastases.

PATIENTS AND METHODS

Bone scans (n=20) preceding radium-223-dichloride treatment for prostate cancer were assessed retrospectively using automated BSI software (EXINI) and by assessing maximum counts per lesion. Results were then compared to total alkaline phosphatase (ALP) as a measure of biochemical response to therapy using linear regressions and to their EOBD scores using box plot analysis.

RESULTS

Moderate correlation was found between ALP response and maximum lesion intensity (R=0.41) and BSI (R=0.46). Strong correlation (R=0.71) was found between baseline ALP and BSI and between lesion number and BSI (R=0.60). Visual assessment of EOBD score was found to correlate well with baseline ALP and maximum ALP response.

CONCLUSION

BSI is a useful asset in stratification of patients with metastatic bone disease. It may also have a place in prediction of biochemical response.

An untapped potential for imaging of peripheral osteomyelitis in paediatrics using [18F]FDG PET/CT -the inference from a juvenile porcine model

PURPOSE

To examine parameters affecting the detection of osteomyelitis (OM) by [18F]FDG PET/CT and to reduce tracer activity in a pig model.

BACKGROUND

[18F]FDG PET/CT is recommended for the diagnosis of OM in the axial skeleton of adults. In children, OM has a tendency to become chronic or recurrent, especially in low-income countries. Early diagnosis and initiation of therapy are therefore essential. We have previously demonstrated that [18F]FDG PET/CT is promising in juvenile Staphylococcus aureus (S. aureus) OM of peripheral bones in a pig model, not failing even small lesions. When using imaging in children, radiation exposure should be balanced against fast diagnostics in the individual case.

METHODS

Twenty juvenile pigs were inoculated with S. aureus. One week after inoculation, the pigs were [18F]FDG PET/CT scanned. PET list-mode acquired data of a subgroup were retrospectively processed in order to simulate and examine the image quality obtainable with an injected activity of 132 MBq, 44 MBq, 13.2 MBq, and 4.4 MBq, respectively.

RESULTS

All lesions were detected by [18F]FDG PET and CT. Some lesions were very small (0.01 cm3), and others were larger (4.18 cm3). SUVmax was higher when sequesters (p = 0.023) and fistulas were formed (p < 0.0001). The simulated data demonstrated that it was possible to reduce the activity to 4.4 MBq without compromising image quality in pigs.

CONCLUSIONS

[18F]FDG PET/CT localized even small OM lesions in peripheral bones. It was possible to reduce the injected activity considerably without compromising image quality, impacting the applicability of PET/CT in peripheral OM in children.

Bone SPECT-based segmented attenuation correction for quantitative analysis of bone metastasis (B-SAC): comparison with CT-based attenuation correction

Background

Evidence has shown the clinical usefulness of measuring the metastatic tumor burden of bone for prognostic assessment especially in prostate cancer; quantitative evaluation by dedicated SPECT is difficult due to the lack of attenuation correction (AC) method.

We developed a novel method for attenuation correction using bone SPECT emission data (bone SPECT-based segmented attenuation correction; B-SAC) where emission data were virtually segmented into three tissues (i.e., bone, soft tissue, and air). Then, the pixel values in SPECT were replaced by 50 for the virtual soft tissue, and − 1000 for the virtual air. The replaced pixel values for the virtual bone were based on the averaged CT values of the normal vertebrae (B-SAC_N) or the metastatic bones (B-SAC_M). Subsequently, the processed SPECT data (i.e., SPECT value) were supposed to realize CT data (i.e., CT value) that were used for B-SAC. The standardized uptake values (SUVs) of 112 metastatic bone tumors in 15 patients with prostate cancer were compared between CTAC with scatter correction (SC) and resolution recovery (RR) and the following reconstruction conditions: B-SAC_N (+)SC(+)RR(+), B-SAC_M (+)SC(+)RR(+), uniform AC(UAC)(+)SC(+)RR(+), AC(−)SC(+)RR(+), and no correction (NC).

Results

The SUVs in the five reconstruction conditions were all correlated with those in CTAC(+)SC(+)RR(+) (p < 0.01), and the correlations between B-SAC_N or B-SAC_M and CTAC images were excellent (r > 0.94). Bland-Altman analysis showed that the mean SUV differences between CTAC (+)SC(+)RR(+) and the other five reconstructions were 0.85 ± 2.25 for B-SAC_N (+)SC(+)RR(+), 1.61 ± 2.36 for B-SAC_M (+)SC(+)RR(+), 1.54 ± 3.84 for UAC(+)SC(+)RR(+), − 3.12 ± 4.97 for AC(−)SC(+)RR(+), and − 5.96 ± 4.59 for NC. Compared to CTAC(+)SC(+)RR(+), B-SAC_N (+)SC(+)RR(+) showed a slight but constant overestimation (approximately 17%) of the metastatic tumor burden of bone when the same threshold of metabolic tumor volume was used.

Conclusions

The results of this preliminary study suggest the potential for B-SAC to improve the quantitation of bone metastases in bone SPECT when X-ray CT or transmission CT data are not available. Considering the small but unignorable differences of lesional SUVs between CTAC and B-SAC, SUVs obtained with the current version of B-SAC seem difficult to be directly compared with those obtained with CTAC.

Value of antigranulocyte scintigraphy with Tc-99m-sulesomab in diagnosing combat-related infections of the musculoskeletal system

AIM

Combat-related extremity injuries are regularly associated with long-term complications such as chronic infection, especially osteomyelitis. Clinical examination and laboratory parameters do not usually allow reliable diagnosis. In contrast, imaging techniques enable constructive assertions to be made about the location and extent of an infection of the peripheral musculoskeletal system. The aim of this study was therefore to determine the diagnostic reliability of three-phase bone scanning and antigranulocyte scintigraphy using Tc-99m-sulesomab (Leukoscan) in the diagnostic clarification of infections associated with combat-related extremity injuries.

METHODS

Twenty-seven male patients (mean age 33.9 years) with suspected combat-associated infections of the extremities were included in this retrospective analysis. All patients underwent three-phase bone scanning using Tc-99m-HDP followed by antigranulocyte scintigraphy with Tc-99m-sulesomab. In 26 of the 27 patients, a CT scan of affected limb was obtained, where the secondary fusion with single photon emission CT data set was possible. The diagnostic reliability of imaging techniques was validated against microbiological samples obtained during surgery and used as gold standard.

RESULTS

Three-phase bone scanning yielded a positive result in all patients, with 18 scans classified as true positive (TP) and nine scans as false positive (FP). This produced a sensitivity of 100%, a specificity of 0% and a positive predictive value (PPV) of 67%. Antigranulocyte scintigraphy recognised 13 patients as TP, 1 patient as FP, 8 patients as true negative (TN) and 5 patients as false negative (FN), which gave a sensitivity of 72%, a specificity of 88%, a PPV of 93%, a negative predictive value (NPV) of 62% and an accuracy of 78%. CT recognised in 7 cases a TP result, in 3 cases an FP, in 5 cases a TN and in 11 cases an FN result. This produced a sensitivity of 39%, a specificity of 63%, a PPV of 70%, an NPV of 31% and an accuracy of 46%.

CONCLUSIONS

Three-phase bone scanning did not deliver any diagnostic benefit, since no result was able to differentiate unequivocally between infection-related and reactive changes. Antigranulocyte scintigraphy using Tc-99m-sulesomab represented a highly suitable technique for diagnostically clarifying combat-related infections of the extremities. It is superior to CT in sensitivity, specificity, PPV, NPV and accuracy.

Consensus document for the diagnosis of prosthetic joint infections: a joint paper by the EANM, EBJIS, and ESR (with ESCMID endorsement)

Background

For the diagnosis of prosthetic joint infection, real evidence-based guidelines to aid clinicians in choosing the most accurate diagnostic strategy are lacking.

Aim and Methods

To address this need, we performed a multidisciplinary systematic review of relevant nuclear medicine, radiological, orthopaedic, infectious, and microbiological literature to define the diagnostic accuracy of each diagnostic technique and to address and provide evidence-based answers on uniform statements for each topic that was found to be important to develop a commonly agreed upon diagnostic flowchart.

Results and Conclusion

The approach used to prepare this set of multidisciplinary guidelines was to define statements of interest and follow the procedure indicated by the Oxford Centre for Evidence-based Medicine (OCEBM).

Electronic supplementary material

The online version of this article (10.1007/s00259-019-4263-9) contains supplementary material, which is available to authorized users.

Bloodpool SPECT as part of bone SPECT/CT in painful total knee arthroplasty (TKA): validation and potential biomarker of prosthesis biomechanics

PURPOSE

To compare bloodpool SPECT with planar imaging in bone SPECT/CT of painful total knee arthroplasty (TKA) with respect to inter-rater agreement, confidence, prosthesis outcome, and biomechanical functioning.

METHODS

Retrospective study of bloodpool SPECT and planar control images. Four raters used the validated Bruderholz scheme and a 5-point scale to grade uptake. Inter-rater agreement and overall confidence scores were calculated. Variable cluster analysis was performed to identify patterns of uptake, and associations between patterns and prosthesis outcome and biomechanical functioning were examined.

RESULTS

In all, 55 knees in 43 patients were analyzed (median follow-up 17 months; revision rate 21.8%). SPECT significantly improved inter-rater agreement in 24% of regions (all P < 0.05) and overall confidence by 20% (P < 0.001). Regional uptake cluster analysis showed improved antero-posterior separation with SPECT, and distinct patterns associated with prosthesis survival in lateral femoral (P = 0.041) and medial tibial (P < 0.001) regions. The prognostic value of SPECT outperformed planar imaging for tibial (P < 0.001), patellar (P = 0.009), and synovial (P = 0.040) assessment. Internal femoral malrotation resulted in increased uptake in posteromedial (P = 0.042) and anterolateral (P = 0.016) femoral, and lateral patellar (P = 0.011) regions. Internal tibial malrotation increased uptake in posterolateral (P = 0.026) and posteromedial tibial (P = 0.005), and medial patellar regions (P = 0.004). Bloodpool SPECT improved the prognostic value of late-phase SPECT/CT for the assessment of the medial tibial region.

CONCLUSIONS

Bloodpool SPECT outperforms planar assessment of painful TKAs and the identification of distinct uptake patterns make it a potentially clinically relevant biomarker of prosthesis survival and biomechanical functioning.

Determining and updating PET/CT and SPECT/CT diagnostic reference levels: A systematic review

The aim of this systematic review is to investigate the national diagnostic reference level (NDRL) methods for positron emission tomography/computed tomography (PET/CT) and single photon emission tomography/computed tomography (SPECT/CT) procedures. A search strategy was based on the preferred, reporting items for systematic review and meta-analysis (PRISMA). Relevant articles retrieved from Medline, Scopus, Web of Science, Embase, Cinahl, and Google Scholar published up to October 2017. The search yielded 1057 articles. Fourteen articles were included in the review after a screening process. Relevant information from the selected articles were summarised and analysed. Discrepancies were found between the methodologies utilised to establish and report both PET/CT and SPECT/CT NDRLs, e.g. patient sampling and administered activity. Further research should focus on reporting more NDRLs for hybrid PET/CT and SPECT/CT examinations, and establish a robust NDRL standard for the CT portion associated with PET/CT and SPECT/CT examinations. This review provides updated NDRL reommndations to deliver more comparable international radation doses for administered activity and CT dose across PET/CT and SPECT/CT clinics.

Use of 18F-sodium fluoride bone PET for disability evaluation in ankle trauma: a pilot study

Background

There are no objective and accurate rating tools for permanent impairment of traumatized ankles. The purpose of this study is to assess the role of 18F-Sodium fluoride (18F-NaF) positron emission tomography-computed tomography (PET/CT) bone scans in evaluating patients with limited ankle range of motion (ROM) after trauma.

Methods

18F-NaF PET/CT was performed in 121 patients (75 men, 46 women; mean age: 45.8) who had ROM < 70% of normal after trauma affecting ankles. Metabolic target volume (MTV), the sum of voxels with standardized uptake value (SUV) > 2.5 was automatically obtained from the 3D volume that included the ankle joint. The maximum & mean SUV (SUVmax & SUVmean), and the total lesion activity (TLA) were measured.

Results

The median period from injury to performing 18F-NaF PET/CT was 290 days. The causes of injury were as follows: fracture (N = 95), Achilles tendon rupture (N = 12), and ligament injury (N = 12). Hot uptake in the ankle was seen in 113 of 121 patients. The fracture group had higher SUVmax, SUVmean, and TLA values than the non-fracture group. More limited ROM correlated with higher hot-uptake parameters (SUVmax, SUVmean, TLA). In subgroup analysis, the same correlations were present in the fracture, but not in the non-fracture group.

Conclusions

18F-NaF PET/CT can provide considerable information in impairment evaluations of limited ankle ROM, particularly in fracture around the ankle. Thus, 18F-NaF bone PET/CT may provide an additional option as an objective imaging tool in disability assessment after ankle injury.