Myxofibrosarcoma of the Chest Wall Detected on 99mTc-MDP Whole-Body Bone Scan

Myxofibrosarcoma is a type of soft tissue sarcoma, predominantly characterized by a high propensity for local recurrence, albeit demonstrating a relatively diminished risk for distant metastasis. Its prevalence is notably higher in elderly patients. Here, we present a case of a 73-year-old woman diagnosed with Myxofibrosarcoma. She was subjected to a whole-body bone scan using 99mTc-methylene diphosphonate (MDP) to survey potential bony metastasis. It revealed marked MDP accumulation with peripheral soft tissue uptake in the right lateral chest region of this patient. This imaging phenotype could potentially be attributed to the augmented vascularity within the tumor, a finding that was prominently displayed in this particular case.

Temporal evolution of postsurgical bone repair in a rabbit model: A [99mTc]Tc-MDP scintigraphic study

Bone regeneration is crucial for repairing bone tissue following various injuries. Research techniques that enable the study of metabolic changes in bone tissue under different conditions are important for understanding bone repair and remodeling. This study used bone scintigraphy to evaluate osteogenesis secondary to osteotomy in a preclinical model of New Zealand rabbits. For this purpose, we conducted a longitudinal, prospective, case-control study in which scintigraphic variables were measured in both the right forearm (case-operated) and the left forearm (control - non-operated). The study sample consisted of 10 rabbits subjected to osteotomy, followed by a 12-week postoperative evaluation period, divided into six imaging stages at 1, 2, 3, 4, 8, and 12 weeks. We observed that the operated forearm showed significantly higher external radiation than the control side, using the pinhole collimator, denoting an increase in the biodistribution and tropism of the radiopharmaceutical to the operated forearm. Among the three evaluated time points, osteoblastic activity was highest in the second week and presented a significant decline in the 8th and 12th weeks, denoting regeneration and resolution of the surgical injury; the control forearm was also influenced by the inactivity imposed by the operated forearm. This fact was notably evidenced by the reduction in the metabolic activity of osteoblasts in the left forearm. Our study suggested that bone scintigraphy was sensitive enough to semi-quantitatively differentiate the metabolic activity of osteoblasts in the operated forearm in the three temporal landmarks evaluated in the study.

Case report: Exploring the utility of whole-body bone scintigraphy for pediatric Langerhans cell histiocytosis: insights from clinical practice

Purpose

This mini-review delves into the realm of Langerhans cell histiocytosis (LCH) in children, focusing on its skeletal involvement. By synthesizing pertinent literature, we sought to provide a comprehensive understanding of LCH's clinical and radiographic spectrum. Our study then demonstrates the diagnostic prowess of whole-body 99mTc-methyl diphosphonate (MDP) scintigraphy in LCH cases, underscoring its value in tandem with existing knowledge.

Methods

Our approach involved an extensive literature review that contextualized LCH within the current medical landscape. Subsequently, we presented a case series featuring five pediatric instances of skeletal LCH, one accompanied by soft tissue infiltration. The principal aim was to illuminate the diagnostic and staging potential of whole-body 99mTc-MDP scintigraphy, augmenting existing insights.

Results

Through meticulous literature synthesis, we highlighted pediatric LCH's protean clinical manifestations and radiological variability. Aligning with this spectrum, our case series underscored the role of 99mTc-MDP scintigraphy in diagnosing and staging LCH. Among the five pediatric cases, one demonstrated concurrent soft tissue involvement. This aligns with the multifaceted nature of LCH presentations.

Conclusion

Pediatric LCH can present with a wide range of clinical and radiologic features. By amalgamating our cases with extant literature, we stress the necessity of a multimodal strategy. 99mTc-MDP scintigraphy emerged as an indispensable tool for accurate staging and soft tissue detection. Our findings collectively advocate for a holistic approach to managing LCH, ensuring informed therapeutic decisions for optimal patient outcomes.

Nuclear medicine imaging for bone metastases assessment: what else besides bone scintigraphy in the era of personalized medicine?

Accurate detection and reliable assessment of therapeutic responses in bone metastases are imperative for guiding treatment decisions, preserving quality of life, and ultimately enhancing overall survival. Nuclear imaging has historically played a pivotal role in this realm, offering a diverse range of radiotracers and imaging modalities. While the conventional bone scan using 99mTc marked bisphosphonates has remained widely utilized, its diagnostic performance is hindered by certain limitations. Positron emission tomography, particularly when coupled with computed tomography, provides improved spatial resolution and diagnostic performance with various pathology-specific radiotracers. This review aims to evaluate the performance of different nuclear imaging modalities in clinical practice for detecting and monitoring the therapeutic responses in bone metastases of diverse origins, addressing their limitations and implications for image interpretation.

Diagnostic capability of 18F-PSMA PET-MRI and pelvic MRI plus bone scan in treatment-naive prostate cancer: a single-center paired validating confirmatory study

BACKGROUND

Radical prostatectomy with pelvic lymph node dissection for the treatment of high-risk localized prostate cancer (PCa) results in long-term benefits in selected patients. But insufficient sensitivity of conventional examinations which are pelvic MRI and bone scan, limits the diagnosis of bone and lymph node metastasis of PCa. This affects the surgical management strategy of a large number of patients. The purpose of this study was to investigate whether 18F-prostate-specific membrane antigen (PSMA) PET-MRI could improve the clinical detection of PCa metastases compared with the conventional pelvic MRI plus bone scan.

MATERIALS AND METHODS

From April 2020 to April 2023, we prospectively enroled 472 patients with histologically proven PCa in our centre, and 120 patients underwent 18F-PSMA PET-MRI, multiparametric MRI, and bone scan before laparoscopic radical prostatectomy plus lymph node dissection. The accuracy of imaging results in detecting lymph node and bone metastatic lesions was compared between PSMA PET-MRI and MRI plus bone scan.

RESULTS

In diagnosing lymph node metastasis, PSMA PET-MRI had an area under the curve (AUC) of 0.844 (95% CI: 0.738-0.949, P < 0.001), sensitivity and specificity of 75% and 96%, which performed apparently better than MRI [AUC=0.615 (95% CI: 0.480-0.750, P =0.073)]. PSMA PET-MRI showed excellent expression in the diagnosis of bone metastases, with an AUC of 0.910 (95% CI: 0.840-0.981, P <0.001) compared to 0.700 (95% CI: 0.577-0.823, P =0.001) in bone scanning. PSMA PET-MRI also had higher sensitivity than bone scanning (90% vs. 43%), while lower specificity (92% vs. 97%).

CONCLUSION

PSMA PET-MRI is superior to conventional imaging at diagnosing metastases in lymph nodes and bones in PCa and can provide a more accurate stagement.

Primary Hyperparathyroidism Mimicking Skeletal Metastasis - A Diagnostic Dilemma

Introduction

Primary hyperparathyroidism (PHPT) is an intrinsic abnormality of the parathyroid glands in which there is an inappropriate secretion of parathormone (PTH), resulting in skeletal resorption and bone loss. The characteristic bony changes of fibrotic cystic lesions are called Brown's tumors. Clinical dilemmas exist due to the varied clinical presentation of hypercalcemia with multiple lytic lesions mimicking metastatic bone disease. The 99 mTc sestamibi scanning is the imaging modality of choice used for the preoperative localization of parathyroid adenomas. Surgery provides a definitive treatment, and the bony lesions resolve completely over a period of time.

Case Report

We present four cases of PHPT where they presented with multiple lytic lesions and were evaluated for metastatic deposits. The diagnosis was confirmed with a biopsy. They were successfully treated by excision of the parathyroid gland. A high index of suspicion will avoid misdiagnosis and inappropriate treatment.

Conclusion

PHPT must be considered as a differential diagnosis for multiple osteolytic bone lesions. Diagnosis can be aided by a thorough clinical examination, including an assessment for neck swelling, and laboratory testing of serum calcium levels and PTH levels. Surgical excision of the hyperactive gland serves as the definitive treatment for this condition, with bony lesions regressing gradually over time.

Bone Scans in Preoperative Investigations of Breast Cancer Cases

BACKGROUND

Breast cancer constitutes about 28% of all new cancer diagnoses in women, making it the most frequently diagnosed cancer among them. Our objective was to assess the role of bone scans (BS) in preoperative investigations of breast cancer.

METHODS

This study involved 105 patients with varying stages of breast cancer, ranging from T1 to T4. We categorized them into three groups: group 1 comprised 40 women with breast cancer who underwent retrospective BS, group 2 included 30 patients with breast cancer who prospectively did not require BS for all cases, and group 3 consisted of 35 women retrospectively diagnosed with breast cancer who did not necessitate BS for all cases. The diagnosis of bone metastasis was confirmed upon obtaining a positive result through bone scintigraphy, subsequently affirmed by another imaging technique such as CT, X-ray, or MRI.

RESULTS

The hospital costs were significantly lower in groups 2 and 3 compared to that of group 1, indicating that performing a BS for every case is unnecessary. It was observed that the time taken for surgery was notably shorter in groups 2 and 3 compared to that of group 1. BS in cases classified as M stage were deemed both costly and time-consuming.

CONCLUSIONS

Routine BS are not cost-effective and represent an unnecessary investment of time. They should not be deemed mandatory as preoperative investigations in breast cancer cases. Instead, they should be considered in conjunction with MRI, particularly in cases of T4 breast cancer.

Assessing the role of positron emission tomography and bone scintigraphy in imaging of pleuropulmonary blastoma (PPB): A report from the International PPB/DICER1 Registry

BACKGROUND

Pleuropulmonary blastoma (PPB) is the most common primary lung neoplasm of infancy and early childhood. Given the rarity of PPB, the role of positron emission tomography (PET) and bone scintigraphy (bone scans) in diagnostic evaluation and surveillance has not been documented to date. Available PET and bone scan data are presented in this study.

PROCEDURES

Patients with PPB enrolled in the International PPB/DICER1 Registry and available PET imaging and/or bone scan reports were retrospectively abstracted.

RESULTS

On retrospective analysis, 133 patients with type II and III (advanced) PPB were identified with available report(s) (PET scan only = 34, bone scan only = 83, and both bone scan and PET = 16). All advanced primary PPB (n = 11) and recurrent (n = 8) tumors prior to treatment presented with 18 F-fluorodeoxyglucose (FDG)-avid lesions, with median maximum standardized uptake values of 7.4 and 6.7, respectively. False positive FDG uptake in the thorax was noted during surveillance (specificity: 59%). Bone metastases were FDG-avid prior to treatment. Central nervous system metastases were not discernable on PET imaging. Sensitivity and specificity of bone scans for metastatic bone disease were 89% and 92%, respectively. Bone scans had a negative predictive value of 99%, although positive predictive value was 53%. Four patients with distant bone metastases had concordant true positive bone scan and PET.

CONCLUSION

Primary, recurrent, and/or extracranial metastatic PPB presents with an FDG-avid lesion on PET imaging. Additional prospective studies are needed to fully assess the utility of nuclear medicine imaging in surveillance for patients with advanced PPB.

Diffuse Cardiac Uptake Misdiagnosed as Cardiac Amyloidosis in Bone Scan

In this presented case, a 77-year-old woman with an implanted prosthesis and ongoing knee pain underwent a bone scan using 99mTc-hydroxydiphosphonate (HDP) in suspicion for bone infection. An incidental finding from this scan revealed diffuse cardiac uptake, necessitating further diagnostic procedures to exclude the possibility of cardiac amyloidosis. In the subsequent 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scan and SPECT images, no perceptible cardiac uptake was observed at all. Upon retrospective review of the patient's medical records, she received 1000 mg of ferric carboxymaltose for iron-deficient anemia the day before the 99mTc-HDP bone scan. Therefore, it was assumed that the diffuse and temporary cardiac activity was due to the transient iron overload. We present and share these bone scan images in order to avoid possible future misinterpretation of cardiac amyloidosis.

PET/CT Imaging of Inflammatory Myofibroblastic Tumor of the Thigh

A 13-year-old male patient presented with right leg pain and walking difficulty. Contrast-enhanced magnetic resonance imaging showed a softtissue lesion between muscle groups in the anterior half of the right thigh. The excisional biopsy result ended in an inflammatory myofibroblastic tumor (IMT). The 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan showed hypermetabolism in the multifocal soft tissue lesion and also confirmed that no other distant foci were present. A three-phase Tc-99m-methylene diphosphonate study of the region showed heterogeneously increased vascularity within the region. We described an unusual case of IMT in a pediatric patient and the importance of PET/CT scanning to delineate the lesion.

Assessment of Radiation Exposure in a Nuclear Medicine Department during 99mTc-MDP Bone Scintigraphy

This study measured 99mTc-MDP bone scintigraphy radiation risks, as low-dose radiation exposure is a growing concern. Dosimeter measurements were taken at four positions (left lateral, right lateral, anterior, and posterior) around the patients at 30, 60, 100, and 200 cm at 0, 1.5, and 3 h. The highest dose rates were recorded from 51% of the patients, who emitted ≥ 25 µSv/h up to 49.00 µSv/h at the posterior location at a distance of 30 cm. Additionally, at the anterior location at a distance of 30 cm, 42% of patients emitted ≥ 25 µSv/h up to 38.00 µSv/h. Furthermore, at 1.5 h after the tracer injection, 7% of the dose rates exceeded 25 µSv/h. There was a significant reduction in mean dose rates for all positions as distance and time increased (p-value < 0.05). As a result, radiation levels decreased with increased distance and time as a result of radiation decay, biological clearance, and distance from the source. In addition, increasing the distance from the patient for all positions reduced the radiation dose, as was substantiated via exponential regression analysis. Additionally, after completing the bone scintigraphy, the patients' dose rates on discharge were within the current guidelines, and the mean radiation doses from 99mTc-MDP were below occupational limits. Thus, medical staff received less radiation than the recommended 25 μSv/h. On discharge and release to public areas, the patients' mean dose rates were as follows: 1.13 µSv/h for the left lateral position, 1.04 µSv/h for the right lateral, 1.39 µSv/h for the anterior, and 1.46 µSv/h for the posterior. This confirms that if an individual was continuously present in an unrestricted area, the dose from external sources would not exceed 20 µSv/h. Furthermore, the patients' radiation doses were below the public exposure limit on discharge.

Prospective Comparison of the Imaging Value of 99m Tc-MDP Bone Scan and 68 Ga-FAPI-04 PET/CT in Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis Syndrome

PURPOSE

This study aimed to explore the imaging value of 68 Ga-FAPI-04 PET/CT in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome and compare it with that of 99m Tc-MDP bone scan.

METHODS

Nineteen participants with SAPHO syndrome underwent 68 Ga-FAPI-04 PET/CT and 99m Tc-MDP bone scan. Demographic data and clinical features were recorded, SAPHO imaging features were analyzed, and the osteoarticular lesion detection rate in both methods was calculated.

RESULTS

This prospective study recruited 4 men and 15 women aged 52.4 ± 8.6 years. The anterior chest wall was involved in all participants (100%). Palmoplantar pustulosis was the most common (36.8%) skin symptom. 99m Tc-MDP bone scan and 68 Ga-FAPI-04 PET/CT together detected 84 osteoarticular lesions, of which 91.7% (77/84) were detected by the former and 96.4% (81/84) by the latter. Furthermore, 68 Ga-FAPI-04 PET/CT detected 5 cases of knee and hip joint synovitis.

CONCLUSIONS

68 Ga-FAPI-04 PET/CT was more sensitive than 99m Tc-MDP bone scan when evaluating osteoarticular lesions in SAPHO syndrome and could also evaluate synovial lesions. 68 Ga-FAPI-04 PET/CT could be a good imaging method for SAPHO syndrome but requires further verification in a more extensive research cohort.

Prevalence of Incidental Findings Suspicious for Transthyretin Cardiac Amyloidosis among Patients Undergoing Bone Scintigraphy: A Systematic Review and a Meta-Analysis

BACKGROUND

The myocardial uptake of bone-seeking tracers suspicious for transthyretin cardiac amyloidosis (ATTR-CA) can be incidentally detected in patients undergoing bone scintigraphy for noncardiac reasons. We conducted a systematic review and meta-analysis to assess the prevalence of these scintigraphic findings.

METHODS

A comprehensive literature search was performed using two bibliographic databases (PubMed/MEDLINE and Cochrane Library), searching for articles related to the review question. Eligible articles were selected, and relevant data were extracted by two authors. The pooled prevalence of incidental findings suspicious for ATTR-CA among patients undergoing bone scintigraphy was calculated on a per-patient-based analysis using a random-effects model. The pooled measure was provided with 95% confidence interval (95% CI) values.

RESULTS

Among 219 records, 11 articles were selected for the systematic review and 10 for the meta-analysis. The pooled prevalence of incidental findings suspicious for ATTR-CA was 1.1% (95% CI: 0.7-1.4%) with heterogeneity due to the characteristics of the included studies, patients, and index tests. These findings are more prevalent in older men.

CONCLUSIONS

The prevalence of incidental findings of ATTR-CA among patients undergoing bone scintigraphy is low but not negligible. Nuclear medicine physicians should suggest, in the scintigraphic report, further clinical investigations when these findings are detected. Prospective studies are warranted.

Comparative study of 18F-DCFPyL PET/CT and 99mTc-MDP SPECT/CT bone imaging for the detection of bone metastases in prostate cancer

Purpose

This study aimed to compare the diagnostic efficiency of 18F-DCFPyL PET/CT imaging and 99mTc-MDP SPECT/CT bone imaging for the detection of bone metastases in prostate cancer.

Methods

A retrospective analysis was conducted on 31 patients with confirmed prostate cancer between September 2020 and September 2022 at China-Japan Union Hospital of Jilin University. All patients underwent 18F-DCFPyL PET/CT and 99mTc-MDP SPECT/CT bone imaging. The gold standard was the pathology or Best Valuable Comparator (BVC) result based on clinical follow-up. Diagnostic performance indicators, including sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV), were analyzed at both the patient and lesion levels. The paired sample chi-square test was used to compare the two imaging methods. Receiver operating characteristic (ROC) curves were plotted, and the area under the curve (AUC) was calculated for each method. The AUC values were compared using the Z-test, and a p-value < 0.05 was considered statistically significant.

Results

Of the 31 prostate cancer patients, 18 were diagnosed with bone metastases, with a total of 84 bone metastatic lesions. At the patient level, 18F-DCFPyL PET/CT imaging showed superior diagnostic performance compared to 99mTc-MDP SPECT/CT bone imaging in all indicators: sensitivity (100% vs. 77.8%, p < 0.01), specificity (92.3% vs. 69.2%, p < 0.05), accuracy (96.8% vs. 74.2%, p < 0.01), PPV (94.7% vs. 77.8%, p < 0.01), and NPV (100% vs. 69.2%, p < 0.01). The AUC values for 18F-DCFPyL PET/CT imaging and 99mTc-MDP SPECT/CT bone imaging were 0.962 and 0.735 (Z = 2.168, p < 0.05). At the lesion level, 18F-DCFPyL PET/CT imaging showed superior diagnostic performance compared to 99mTc-MDP SPECT/CT bone imaging in all indicators: sensitivity (97.6% vs. 72.6%, p < 0.01), specificity (95.7% vs. 73.9%, p < 0.01), accuracy (97.2% vs. 72.9%, p < 0.01), PPV (98.8% vs. 91.0%, p < 0.01), and NPV (91.7% vs. 42.5%, p < 0.01). The AUC values for 18F-DCFPyL PET/CT imaging and 99mTc-MDP SPECT/CT bone imaging were 0.966 and 0.733 (Z = 3.541, p < 0.001).

Conclusion

Compared with 99mTc-MDP SPECT/CT bone imaging, 18F-DCFPyL PET/CT imaging demonstrated higher diagnostic efficiency for bone metastases in prostate cancer, and it can more accurately determine the presence of bone metastases. It is an important supplement to imaging examination for prostate cancer patients and has great potential and broad application prospects.

Meningioma Mimicking Bone Metastasis in Breast Cancer

Meningiomas constitute 37% of primary central nervous system tumors and are more common in women. Also may occur with other primary malignancies, which can cause confusion with the metastasis in whole body bone scan (WBBS) imaging. A 58-year-old woman diagnosed with breast cancer was referred to the WBBS for the investigation of possible bone metastases. In the planar images, radiotracer uptake at multiple sites was detected on the anterior side of the skull base and the posterior side of the vertex of the cranium. Single photon emission computed tomography/computed tomography was performed for anatomical localization of possible metastatic lesions, and it revealed that detected accumulations of radiotracer did not belong to the bone metastases; uptakes were located at the cerebral parenchyma and the lesions in the falx cerebri. Patient history explained that she had been diagnosed with meningioma five years ago, which mimicked bone metastases in this study.

Polyostotic Fibrous Dysplasia in a Six-year-Old Boy

Fibrous dysplasia (FD) is a rare congenital benign bone disease that manifests as a defect in the bone remodeling process, affecting the function, differentiation, and maturation of osteoblasts. This process is located in the bone marrow, where the normal marrow tissue is replaced with immature bone islands and fibrous stroma. The etiology is unclear so far, but it is known to be connected with a point mutation of the gene that encodes Gs α protein at the time of embryogenesis, and because of that, all of the affected somatic cells become dysplastic. It is important to determine whether the mutation occurred earlier in the process of embryogenesis so that there will be more mutant cells and the disease will appear in a more severe form. The clinical presentation of FD is variable, so there are plenty of potential differential diagnoses. The most common include Paget disease, non-ossifying fibroma, osteofibrous dysplasia, aneurysmal bone cyst, adamantinoma, giant cell tumor, fracture callus, and low-grade central osteosarcoma.

Semi-Quantification of Myocardial Uptake of Bone-Seeking Agents in Suspected Cardiac Amyloidosis

INTRODUCTION

Bone scintigraphy has emerged as a key tool for non-invasive etiologic diagnosis of transthyretin (ATTR) cardiac amyloidosis (CA). We focused on a new semi-quantification method (on planar imaging) that could complement the qualitative/visual Perugini scoring system, especially when SPET/CT is not available.

MATERIAL AND METHODS

We retrospectively/qualitatively evaluated 8674 consecutive, planar 99mTc-biphosphonate scintigraphies (performed for non-cardiac reasons), identifying 68 (0.78%) individuals (mean age 79 ± 7 years, range 62-100 years; female/male ratio 16/52) presenting myocardial uptake. Due to the retrospective nature of the study, no SPET/CT, pathologic or genetic confirmation was obtained. The Perugini scoring system was determined (in patients presenting cardiac uptake) and compared with three newly proposed semi-quantitative indices. We took 349 consecutive bone scintigraphies, qualitatively absent of any cardiac/pulmonary uptake, as "healthy controls" (HC).

RESULTS

The heart-to-thigh ratio (RHT) and lung-to-thigh ratio (RLT) indices were significantly higher in patients than in HCs (p ≤ 0.0001). There were statistically significant differences for RHT in HCs vs. patients with qualitative Perugini scores of 1 or >1 (with p ranging from ≤0.001 to ≤0.0001). ROC curves showed that RHT outperformed the other indices and was more accurate in both male and female groups. Furthermore, in the male population, RHT accurately distinguished HCs and patients with scores of 1 (less likely affected by ATTR) from patients with qualitative scores >1 (more likely affected by ATTR) with an AUC of 99% (sensitivity: 95%; specificity: 97%).

CONCLUSION

The proposed semi-quantitative RHT index can accurately/semi-quantitatively distinguish between HCs and subjects probably affected by CA (Perugini scores from 1 to 3), and could be particularly useful when no SPET/CT data are available (such as in retrospective studies and data mining). Furthermore, RHT can semi-quantitatively predict, with very high accuracy, subjects in the male population more likely to be affected by ATTR. The present study, although using a very large sample, is however retrospective, monocentric, and therefore the generalizability of the results should be proved by an accurate external validation.

ADVANCES IN KNOWLEDGE

The proposed heart-to-thigh ratio (RHT) can distinguish healthy controls and subjects that are probably affected by cardiac amyloidosis in a simple and more reproducible way, as compared to standard qualitative/visual evaluation.

Is The Patient Actually Failing On Enzalutamide? A Case Report And Issues To Consider In Enzalutamide-Resistant Oligo Progressive Metastatic Castrate-Resistant Prostate Cancer

BACKGROUND

Metastatic castrate-resistant prostate cancer (mCRPC) is a challenging disease, especially in heavily pretreated patients. Androgen pathway inhibitors have contributed to a notable improvement in the overall survival and quality of life in patients with mCRPC during the last decade. Still, a considerable percentage of patients are unable to draw benefits from this drug category and are deprived of a treatment that offers limited toxicity and preserves a good quality of life. The mechanisms leading to this pre-existing or acquired resistance, as well as the possible strategies to overcome this resistance have been put at the center of scientists' attention.

CASE PRESENTATION

With the present report we present the case of a 70-year-old patient with mCRPC, who was apparently an enzalutamide non-responder, but a multimodal approach with enzalutamide continuation and irradiation to his symptomatic oligoprogressive disease converted him to a responder with clinical, biochemical and imaging response; furthermore, we discuss the existing data providing evidence for the use of metastasis-directed therapy in combination with androgen pathway inhibitors in order to overcome drug resistance in patients with oligoprogressive disease.

CONCLUSION

A considerable proportion of patients with oligometastatic or oligoprogressive prostate cancer who seem not to respond to androgen pathway inhibitors, such as enzalutamide, due to preexisting or acquired resistance, could benefit from MDT with a multimodal treatment approach. This strategy allows androgen pathway inhibitor continuation beyond biochemical progression and delays the switch to next-line systemic treatment.

Whole‑body MRI for metastatic workup in patients diagnosed with cancer

Early diagnosis and appropriate staging workup are crucial for cancer patients. Whole-body magnetic resonance imaging (WB-MRI) has been proposed as another practical whole-body approach for assessing local invasiveness and distant metastases in patients newly diagnosed with cancer. The current study aimed to evaluate the efficacy of WB-MRI in assessing metastasis in patients newly diagnosed with cancer using histopathologic data as the reference method. A prospective observational study was performed from April 2018 to July 2020. MRI sequences were utilized to acquire anatomical and functional images in three orthogonal planes. The discovery was classified as nodal, skeletal and visceral metastases. Patient-based analysis was used for visceral metastasis and region-based for skeletal, systemic and lymph node metastases. A total of 43 consecutive patients (mean age, 56±15.2 years) were assessed successively. In 41 patients, there was a concordance between the WB-MRI and histological confirmation. The most prevalent site of metastasis was the skeletal system (18 patients). There were 12 individuals with liver metastasis, 10 with lung metastasis and 4 with peritoneal metastasis, with just one brain metastatic lesion found. On WB-MRI, 38 lymph node groups were deemed positive. Out of the total, 66 skeletal locations contained metastases. The accuracy of WB-MRI for nodal, skeletal and visceral metastases was (98.45, 100 and 100%, respectively). In conclusion, WB-MRI in three orthogonal planes, including the diffusion-weighted MRI with background body signal suppression sequence, may be utilized efficiently and accurately for assessing metastasis staging and may thus be utilized in patients with newly diagnosed cancer.

A Comparison of Magnetic Resonance Imaging and SPECT-CT Imaging in Complex Spine Pathology: Does SPECT-CT Provide Additional Diagnostic Information Over Magnetic Resonance Imaging?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Magnetic Resonance Imaging (MRI) is often regarded as the gold standard for spinal pathology, as it provides good structural visualisation. SPECT-CT, however, provides combined structural and functional information. There is a paucity of literature comparing SPECT-CT with MRI in the spine. Our aim was to determine whether SPECT-CT provides additional information to MRI in individuals with complex spinal pathology, including deformity, which altered management.

METHODS

We conducted a retrospective review of all individuals seen at our tertiary spinal unit that were investigated with both MRI and SPECT-CT of the spine between 2007-2020. We reviewed imaging reports, and collated diagnoses, surgical treatment and the relative contributions of MRI and SPECT-CT to management decisions.

RESULTS

104 individuals identified, with a mean age of 30 years (89 females and 15 males). Diagnostic categories were adolescent, adult, and congenital deformity, degenerative pathology, and miscellaneous pathology. MRI returned positive findings in 58 (55.8%), and SPECT-CT in 41 (39.4%) cases. SPECT-CT identified 10 cases of facet joint degeneration, 5 of increased uptake around metalwork suggestive of loosening, 1 pseudoarthrosis, 1 partial failure of fusion and 1 osteoid osteoma which were not reported on MRI, all in individuals who had previously undergone spinal instrumentation. Despite this, SPECT-CT only altered management for 6 individuals (5.8%).

CONCLUSIONS

MRI is less useful in the setting of previous instrumentation due to metal artefact. Where MRI is inconclusive, particularly in individuals with previous spinal instrumentation, SPECT-CT may provide a diagnosis, but is not recommended as primary imaging.

Adverse Clinical Events at the Injection Site Are Exceedingly Rare After Reported Radiopharmaceutical Extravasation in Patients Undergoing 99mTc-MDP Whole-Body Bone Scintigraphy: A 12-Year Experience

The deleterious effects of high-dose radiation on normal tissue are sometimes extrapolated to diagnostic (SPECT and PET) radiopharmaceutical extravasation (RPE). It has been hypothesized that diagnostic RPE can have gradually evolving local tissue injury and a potentially increased risk of local dermatologic or oncologic diseases over a longer period. However, data on clinical adverse events after diagnostic RPE are limited. Therefore, our primary aim was to study the occurrence of short-term and long-term clinical adverse events in patients who underwent ^99mTc-methylene diphosphonate (^99mTc-MDP) whole-body bone scintigraphy (WBBS) with reported RPE. Methods: The records of ^99mTc-MDP WBBS performed from June 2010 to January 2022 were retrospectively examined for RPE documented in the scan reports. The clinical records of patients with a documented RPE were extensively reviewed for any related short-term adverse events (within 2 wk of the WBBS: local symptoms and care sought for local dermatologic or musculoskeletal issues) and long-term adverse events (until the last follow-up: local deleterious effects and related consults for dermatology, plastic surgery, oncology, or orthopedics). Results: Retrospective review of the records of 31,679 ^99mTc-MDP WBBS studies showed RPE documented in 118 (0.37%). Medical records were not retrievable for 22 patients, yielding a final cohort of 96 patients with reported RPE. The median follow-up was 18.9 mo (interquartile range, 7.8-45.7 mo). Short-term events were noted in 4 patients, of whom one was asymptomatic. Of the 3 symptomatic patients, 2 experienced mild discomfort at the injection site, and 1 had tender swelling. Three of the 4 events were in patients who had a prior intravenous contrast extravasation for contrast-enhanced CT performed earlier during the day and a ^99mTc-MDP injection later at the same site, likely leading to RPE. None of the long-term local events had any plausible link with the RPE event. Conclusion: Reported RPE was rare, and 3 patients (0.009%) had short-term local symptoms, all of which were likely related to the prior higher-volume intravenous contrast extravasation. The smaller-volume diagnostic radiopharmaceutical injections for WBBS are highly unlikely to cause local symptoms on their own. No patient had any long-term adverse event with a plausible link to the RPE.

Not All Glittering Bone Lesions Are Gold: A Case of Sclerotic Bone Lesions with Elevated 68 Ga PSMA and 99m Tc HDP Uptake with No Signs of Malignancy

Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography ( ⁶⁸ Ga PSMA PET/CT) outperforms CT and bone scintigraphy in terms of diagnostic accuracy for the primary staging of prostate cancer and has become widely used. However, ⁶⁸ Ga PSMA uptake is also encountered in nonprostatic tissue. We present a 63-year-old male with newly diagnosed high-risk prostate cancer who underwent bone scintigraphy with single-photon emission computed tomography/computed tomography (SPECT/CT), which showed inhomogeneous elevated uptake in sclerotic bone lesions in the pelvis. Likewise, ⁶⁸ Ga PSMA PET/CT revealed inhomogeneous uptake in the same areas. Subsequent biopsy revealed hyperplastic bone marrow without signs of malignancy. The patient underwent radical prostatectomy, and the prostate-specific antigen level dropped to less than 0.1 ng/mL.

Artificial Intelligence of Object Detection in Skeletal Scintigraphy for Automatic Detection and Annotation of Bone Metastases

BACKGROUND

When cancer has metastasized to bone, doctors must identify the site of the metastases for treatment. In radiation therapy, damage to healthy areas or missing areas requiring treatment should be avoided. Therefore, it is necessary to locate the precise bone metastasis area. The bone scan is a commonly applied diagnostic tool for this purpose. However, its accuracy is limited by the nonspecific character of radiopharmaceutical accumulation. The study evaluated object detection techniques to improve the efficacy of bone metastases detection on bone scans.

METHODS

We retrospectively examined the data of 920 patients, aged 23 to 95 years, who underwent bone scans between May 2009 and December 2019. The bone scan images were examined using an object detection algorithm.

RESULTS

After reviewing the image reports written by physicians, nursing staff members annotated the bone metastasis sites as ground truths for training. Each set of bone scans contained anterior and posterior images with resolutions of 1024 × 256 pixels. The optimal dice similarity coefficient (DSC) in our study was 0.6640, which differs by 0.04 relative to the optimal DSC of different physicians (0.7040).

CONCLUSIONS

Object detection can help physicians to efficiently notice bone metastases, decrease physician workload, and improve patient care.

Erratum: A novel approach for fibrous dysplasia assessment using combined planar and quantitative SPECT/CT analysis of Tc-99m-diphosphonate bone scan in correlation with biological bone turnover markers of disease activity

[This corrects the article DOI: 10.3389/fmed.2022.1050854.].

Safely omitting bone isotope scans in a cohort of grade group 2 prostate cancer

OBJECTIVE

A retrospective review conducted in our urology unit to assess the efficiency for requesting bone scans for newly diagnosed prostate cancer patients, aiming to minimize radiation exposure and avoiding unnecessary investigations as cost effective measure.

METHODS

A retrospective observational study included 360 patients with newly diagnosed prostate cancer within urology department at Calderdale and Huddersfield NHS Trust from April 2016 to March 2018. Parameters observed were: the prostatic specific antigen (PSA) on diagnosis, Gleason score, staging magnetic resonance imaging, and bone scans. We analyzed the possible correlation of the Gleason score and PSA to determine the risk of bony metastasis. Regarding PSA: Patients were categorized as with PSA <15, PSA ≥15. Regarding Gleason score: Patients were categorized as patients with grade group 1 or 2 and patients with grade group 3 and above. Data recorded was then analyzed using χ²  analysis to determine if results were deemed significant or not.

RESULTS

A total of 360 patients: 91 patients (25%) had positive bony metastasis. While 269 patients (75%) had a clear bone scan. Among patients with grade group 3 or above or having PSA ≥15, 90 patients out of 324 patients had bony metastasis (38%). Among patients with grade group 1 or 2 and PSA <15, only 1 patient out of 36 had bony metastasis (2.7%). Negative predictive value of grade group 1 or 2 and PSA <15 for bony metastasis was 97.22%.

CONCLUSION

Using a cutoff level of PSA <15 in grade group 1 and 2 seems to be a safe and efficient tool to exclude newly diagnosed prostate cancer patients from having an isotope bone scan for staging purpose.

Comparison of PSMA-based 18F-DCFPyL PET/CT and Tc-99m MDP bone scan in detection of bone metastasis in prostate cancer

While Tc-99m MDP bone scan (BS) remains the conventional standard for detection of bone metastasis in prostate cancer, newly FDA-approved imaging with PSMA-based ¹⁸F-DCFPyL PET/CT has shown promise for early detection of metastatic disease. However, a paucity of data remains in the diagnostic accuracy of PSMA PET/CT in detecting bone metastasis compared to BS. This retrospective study included 91 patients who received both BS and PSMA PET/CT within a 3-month interval from August 2021 to February 2022. Separate concurrent primary cancer, interval PSA levels greater than a 2-fold difference (or absolute difference >1 ng/ml) between the two studies were excluded. All abnormal bone lesions on either scan were compared. The findings were verified by pathological findings and/or 6-month clinical follow-up. High concordance (78%) was found between modalities with discordant findings (20/91, 22%) demonstrating more false positives (4/20, 20%) and false negatives (3/20, 15%) on BS compared to PET/CT. Additionally, more bone metastases were detected on PSMA PET/CT (13/20, 65%) with all true positive BS lesions also detected PET/CT. The sensitivity, specificity, PPV and NPV for BS were 89%, 91%, 80%, and 95% respectively; and 100%, 97%, 93%, and 100% for ¹⁸F-DCFPyL PET/CT respectively. Our results demonstrate that ¹⁸F-DCFPyL PET/CT identified more bone metastases while also identifying all bone metastases identified on BS. With the added diagnostic value of detecting primary tumor and soft tissue metastasis, ¹⁸F-DCFPyL PET/CT may render BS unnecessary to investigate bone metastases in patients with prostate cancer.

Prostatic bed calcification with MDP uptake: Easy to miss on planar images

A 65 years old man with high-risk prostate adenocarcinoma underwent bone scintigraphy with 99mTc-methylene diphosphate (99mTc-MDP). The scan revealed a focus of radiotracer uptake in the left pubic region, which was suspicious for metastatic involvement. Additional imaging with single photon emission computed tomography (SPECT/CT) confined the uptake to be extra-osseous and contributed to the calcified zone in the prostate bed. Prostatic bed calcification with 99mTc-MDP uptake mimics metastasis and can be easily missed on planar images.

Survival in Breast Cancer Patients with Bone Metastasis: A Multicenter Real-World Study on the Prognostic Impact of Intensive Postoperative Bone Scan after Initial Diagnosis of Breast Cancer (CSBrS-023)

The prognostic value of intensive postoperative bone scan (BS) screening, which is performed in asymptomatic patients with breast cancer (BC) after surgery, remained unclear. Patients diagnosed with BC with bone metastasis (BM) from five medical centers in China during the years 2005−2013 were retrospectively collected. Propensity score matching (PSM) was performed to balance the baseline characteristics. The survival outcomes were overall survival (OS) and overall survival after BM (OSABM). Among 1059 eligible patients, 304 underwent intensive postoperative BS while 755 did not. During a median follow-up of 6.67 years (95%CI 6.45, 7.21), intensive postoperative BS prolonged the median OS by 1.63 years (Log-Rank p = 0.006) and OSABM by 0.66 years (Log-Rank p = 0.002). Intensive postoperative BS was an independent prognostic factor for both OS (adjusted HR 0.77, 95%CI 0.64, 0.93, adjusted p = 0.006) and OSABM (adjusted HR 0.71, 95%CI 0.60, 0.86, adjusted p < 0.001). The prognostic value of intensive postoperative BS was consistently favorable for OS among clinical high-risk patients, including those with ages younger than 50, stage II, histology grade G3 and ER-Her2- subtype. This multicenter real-world study showed that intensive postoperative BS screening improved survival for BC patients with BM and should probably be recommended for postoperative surveillance, especially for patients at clinical high-risk.

The effect of extracorporeal shock wave therapy on large neurogenic heterotopic ossification in a patient with pontine hemorrhage: A case report and literature review

RATIONALE

Heterotopic ossification (HO), an ectopic bone formation in soft tissue around the joint, is a complication observed in stroke patients. HO around the hip joint causes a reduction in the functional ability of patients by generating pain and limiting range of motion (ROM). In addition, it results in impaired mobility, ultimately affecting quality of life and increasing the mortality of patients. Extracorporeal shock wave therapy (ESWT) has demonstrated efficacy in treating soft tissue inflammation and has been used to reduce patients' pain in HO. However, almost none of the studies reported degradation in the size of HO on images obtained before and after ESWT application.

PATIENT CONCERNS AND DIAGNOSIS

We report a case of a 36-year-old man who developed HO around both hip joints 3 months after bilateral pontine hemorrhage.

INTERVENTIONS

Seven months after HO development, ESWT was administered to the area of HO every other day for a total of 10 sessions.

OUTCOMES

Immediately following treatment, the ROM of both hip joints increased. Thus the patient was able to maintain a sitting posture without having to be bound to the wheelchair. In addition, the tolerable sitting time before groaning increased from less than ten minutes to almost 60 minutes by the end of all ESWT sessions. Unlike other previous reports, a diminished HO size was confirmed by comparing plain X-rays and bone scans obtained before and after treatment sessions.

LESSONS

In this case, we report an objective size reduction in HO in radiologic findings after applying ESWT to both hips. ESWT is a safe, easy-to-apply, and noninvasive modality. We would like to emphasize the use of ESWT as a treatment option for HO to decrease the extent of HO, as well as to improve pain, spasticity and function in patients with stroke.

A Case of Extracranial Metastasis of Glioblastoma Multiforme Seen on Bone Scintigraphy

Glioblastoma multiforme (GBM) is the most common primary malignant tumor of the central nervous system in adults. It is known for its devastating intracranial progress thus attributing to its very short survival. Here, we report a case of 37-year-old female with GBM post surgery, chemotherapy and radiotherapy who presented with pain in right hip region. She was referred to our department for evaluation of skeletal metastasis. Tc-99m methylene diphosphonate bone scan revealed an expansile lesion involving the right iliac blade along with extensive lytic bony lesions throughout the axial skeleton.

Rates of metastatic prostate cancer in newly diagnosed patients: Numbers needed to image according to risk level

BACKGROUND

The numbers needed to image to identify pelvic lymph node and/or distant metastases in newly diagnosed prostate cancer (PCa) patients according to risk level are unknown.

METHODS

Relying on Surveillance, Epidemiology, and End Results (2010-2016), we tabulated rates and proportions of patients with (a) lymph node or (b) distant metastases according to National Comprehensive Cancer Network (NCCN) risk level and calculated the number needed to image (NNI) for both endpoints. Multivariable logistic regression analyses were performed.

RESULTS

Of 145,939 newly diagnosed PCa patients assessable for analyses of pelvic lymph node metastases (cN1), 4559 (3.1%) harbored cN1 stage: 13 (0.02%), 18 (0.08%), 63 (0.3%), 512 (2.8%), and 3954 (14.9%) in low, intermediate favorable, intermediate unfavorable, high, and very high-risk levels. These resulted in NNI of 4619, 1182, 319, 35, and 7, respectively. Of 181,109 newly diagnosed PCa patients assessable for analyses of distant metastases (M1_a-c ), 8920 (4.9%) harbored M1_a-c stage: 50 (0.07%), 45 (0.1%), 161 (0.5%), 1290 (5.1%), and 7374 (22.0%) in low, intermediate favorable, intermediate unfavorable, high, and very high-risk. These resulted in NNI of 1347, 602, 174, 20, and 5, respectively.

CONCLUSIONS

Our observations perfectly validated the NCCN recommendations for imaging in newly diagnosed high and very high-risk PCa patients. However, in unfavorable intermediate-risk PCa patients, in whom bone and soft tissue imaging is recommended, the NNI might be somewhat elevated to support routine imaging in clinical practice.

Equine skeletal scintigraphy: Comparing normal bone-to-soft tissue ratio 2 and 4 hours after injection with either hydroxymethylene diphosphonate or methylene diphosphonate

BACKGROUND

In equine skeletal scintigraphy, there is no information about the possible influence of different phosphonate compounds on image quality.

METHODS

This prospective randomised study determined bone uptake changes and image quality for hydroxymethylene diphosphonate (HDP) and methylene diphosphonate (MDP) in equine patients at different time points. Scintigraphic images of the radius and the tibia of 20 horses were acquired at 2 and 4 hours after injection of either technetium-labelled HDP or MDP. Three regions of interest were identified-in the bone diaphysis, adjacent soft tissue and background area-to determine the normal bone-to-soft tissue ratio (BSR). Qualitative analysis was performed using a modified scoring system.

RESULTS

In terms of BSR and count rates, HDP showed a slightly better incorporation into bone compared to MDP, but significant differences were only detected for count rates at 4 hours after injection (p = 0.048). The radiopharmaceutical used did not influence qualitative image scoring, which was correlated with the BSR (ρ = 0.49; p ≤ 0.001).

CONCLUSION

The choice of HDP or MDP for equine skeletal scintigraphy does not seem to substantially affect BSR and qualitative image scoring. Further studies with a larger sample size, including the evaluation of lesion detection ability for both bone-seeking agents, are needed.

Bone Scan With SPECT/CT Demonstrated C1 to C2 Involvement in Rheumatic Arthritis

ABSTRACT

An 80-year-old man was treated with rituximab for active rheumatoid arthritis until 2019, now controlled with Salazopyrin, prednisolone, methotrexate, and folic acid. However, laboratory data showed elevated C-reactive protein and erythrocyte sedimentation rate. Whole-body bone scan showed bony and joint destruction to the upper cervical vertebra (C spine), bilateral shoulders, wrists, finger joints, ankles, and left knee. SPECT/CT localized the upper C spine uptake to the C1/C2 joint and adjacent C1 and C2 with C1/C2 subluxation. C spine CT showed vertical atlantoaxial subluxation and bony erosions.

Metabolic Activity of Neurogenic Heterotopic Ossification on 18F-FDG PET/CT Matching with Ongoing Osteoblastic Activity on Bone Scan

A 54-year-old man, with previous history of neurogenic heterotopic ossification (HO) in muscles around the left hip following a spinal cord injury ten months earlier, was referred to our nuclear medicine center for an ¹⁸fluorine-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to rule out a spondylodiscitis. No sign of spondylodiscitis was found on ¹⁸F-FDG PET/CT, but images revealed an increased ¹⁸F-FDG uptake in HO areas, matching with ongoing osteoblastic activity on a following bone scan.

Segmented linear correlations between bone scan index and prostate cancer biomarkers, alkaline phosphatase, and prostate specific antigen in patients with a Gleason score ≥7

Technetium-99m methyl diphosphonate bone scintigraphy is relatively easily accessible for detecting bone metastases in prostate cancer patients. However, it is subjective and can be challenging to compare images taken at different time points. The bone scan index (BSI) is a more objective evaluation and allows for better comparison of images. Its correlation with other biomarkers of prostate cancer metastases such as prostate specific antigen (PSA) and alkaline phosphatase (ALP) is not clearly understood. This study thus aimed to compare the BSI correlation to PSA against that of BSI to ALP levels in patients with a Gleason score ≥7.A retrospective analysis of the medical records of 50 prostate cancer patients with a Gleason score of ≥7 referred for a bone scan between January 1, 2015 and December 31, 2018 was undertaken. Bone scans were interpreted visually, and using a semi-automated computer programme to quantify the BSI and its relation to PSA and ALP measurements.For the metastasis positive measurements, there was a statistically significant moderate positive overall linear correlation between BSI and PSA. For ALP and BSI, there were 2 segmented strong positive linear relationships between them. The first segment consisted of ALP < 375 IU/L and BSI >10%, where ALP and BSI were strongly and positively correlated. The other segment tended to have generally low BSI measurements (<10%) and also had a strong and positive correlation.The BSI was found to be better linearly correlated with ALP than PSA.

Application of 68Ga-citrate PET/CT for differentiating periprosthetic joint infection from aseptic loosening after joint replacement surgery

AIMS

We aimed to evaluate the utility of ⁶⁸Ga-citrate positron emission tomography (PET)/CT in the differentiation of periprosthetic joint infection (PJI) and aseptic loosening (AL), and compare it with ^99mTc-methylene bisphosphonates (^99mTc-MDP) bone scan.

METHODS

We studied 39 patients with suspected PJI or AL. These patients underwent ⁶⁸Ga-citrate PET/CT, ^99mTc-MDP three-phase bone scan and single-photon emission CT (SPECT)/CT. PET/CT was performed at ten minutes and 60 minutes after injection, respectively. Images were evaluated by three nuclear medicine doctors based on: 1) visual analysis of the three methods based on tracer uptake model, and PET images attenuation-corrected with CT and those not attenuation-corrected with CT were analyzed, respectively; and 2) semi-quantitative analysis of PET/CT: maximum standardized uptake value (SUVmax) of lesions, SUVmax of the lesion/SUVmean of the normal bone, and SUVmax of the lesion/SUVmean of the normal muscle. The final diagnosis was based on the clinical and intraoperative findings, and histopathological and microbiological examinations.

RESULTS

Overall, 23 and 16 patients were diagnosed with PJI and AL, respectively. The sensitivity and specificity of three-phase bone scan and SPECT/CT were 100% and 62.5%, 82.6%, and 100%, respectively. Attenuation correction (AC) at 60 minutes and non-AC at 60 minutes of PET/CT had the same highest sensitivity and specificity (91.3% and 100%), and AC at 60 minutes combined with SPECT/CT could improve the diagnostic efficiency (sensitivity = 95.7%). Diagnostic efficacy of the SUVmax was low (area under the curve (AUC) of ten minutes and 60 minutes was 0.814 and 0.806, respectively), and SUVmax of the lesion/SUVmean of the normal bone at 60 minutes was the best semi-quantitative parameter (AUC = 0.969).

CONCLUSION

⁶⁸Ga-citrate showed the potential to differentiate PJI from AL, and visual analysis based on uptake pattern of tracer was reliable. The visual analysis method of AC at 60 minutes, combined with ^99mTc-MDP SPECT/CT, could improve the sensitivity from 91.3% to 95.7%. In addition, a major limitation of our study was that it had a limited sample size, and more detailed studies with a larger sample size are warranted. Cite this article: Bone Joint Res 2022;11(6):398-408.

Seeing the Invisible: The Value of Bone Scan to Distinguish Chondroblastic Osteosarcoma From Prosthesis Loosening

ABSTRACT

A 76-year-old woman with uterine cervical cancer 20 years ago received right total hip replacement 3 months ago for right hip avascular necrosis without specific intraoperative finding. She reported persistent right hip pain after falling from bed. Pelvic x-ray showed right pubic ramus fracture. To evaluate prosthesis loosening, 99mTc-MDP 3-phase bone scan was arranged, showing diffusely and heterogeneously increased vascularity and tracer perfusion over the right hip, with intensely and heterogeneously increased metabolism in the right iliac bone and hip. SPECT/CT showed nearby swelling of calcified muscles. After debridement and synovectomy, the pathologic report showed chondroblastic osteosarcoma.

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.

A novel approach for fibrous dysplasia assessment using combined planar and quantitative SPECT/CT analysis of Tc-99m-diphosphonate bone scan in correlation with biological bone turnover markers of disease activity

Purpose

To investigate the emerging role of Tc-99m-labeled diphosphonate (Tc-99m-DPD) uptake quantification by SPECT/CT in fibrous dysplasia (FD) bone lesions and its correlation with biological bone turnover markers (BTMs) of disease activity.

Materials and methods

Seven patients (49 ± 16 years) with a confirmed diagnosis of FD were included in this retrospective study. Bone scans with Tc-99m-DPD and quantitative SPECT/CT (xSPECT/CT) were performed. SUV_max (maximum standard unit value) and SUV_mean (mean standard unit value) were measured in all FD bone lesions. The skeletal burden score (SBS) was assessed on planar scintigraphy and multiplied by mean SUV _max and SUV_mean to generate two new parameters, SBS_SUV_max and SBS_SUV_mean, respectively. Planar and xSPECT/CT quantitative measures were correlated with biological BTMs of disease activity, including fibroblast growth factor 23 (FGF-23), alkaline phosphatase (ALP), procollagen 1 intact N-terminal propeptide (P1NP) and C-terminal telopeptide (CTX), as well as scoliosis angle measured on radiographs. Statistical significance was evaluated with Spearman's correlations.

Results

A total of 76 FD bone lesions were analyzed, showing an average SUV_max and SUV_mean (g/mL) of 13 ± 7.3 and 8 ± 4.5, respectively. SBS, SBS_SUV_max and SBS_SUV_mean values were 30.8 ± 25.6, 358 ± 267 and 220.1 ± 164.5, respectively. Mean measured values of FGF-23 (pg/mL), ALP (U/L), P1NP (μg/L) and CTX (pg/mL) were 98.4 (22-175), 283.5 (46-735), 283.1 (31-1,161) and 494 (360-609), respectively. Mean scoliosis angle was 15.7 (7-22) degrees. We found a very strong positive correlation between planar-derived SBS and CTX (r = 0.96, p = 0.010), but no significant correlation between SUV_max or SUV_mean and biological BTMs. SBS_SUV_max showed a strong to very strong positive correlation with CTX (ρ = 0.99, p = 0.002), FGF-23 (ρ = 0.91, p = 0.010), ALP (ρ = 0.82, p = 0.020), and P1NP (ρ = 0.78, p = 0.039), respectively.

Conclusion

This study showed that biological BTMs are significantly correlated with diphosphonate uptake on bone scan, quantified by a new parameter combining information from both planar and quantitative SPECT/CT. Further analysis of bone scan quantitative SPECT/CT data in a larger patient population might help better characterize the skeletal disease burden in FD, and guide treatment and follow-up.

An optimized imaging protocol for [99mTc]Tc-DPD scintigraphy and SPECT/CT quantification in cardiac transthyretin (ATTR) amyloidosis

BACKGROUND

In [99mTc]Tc-DPD scintigraphy for myocardial ATTR amyloidosis, planar images 3 hour p.i. and SPECT/CT acquisition in L-mode are recommended. This study investigated if earlier planar images (1 hour p.i.) are beneficial and if SPECT/CT acquisition should be preferred in H-mode (180° detector angle) or L-mode (90°).

METHODS

In SPECT/CT phantom measurements (NaI cameras, N = 2; CZT, N = 1), peak contrast recovery (CRpeak) was derived from sphere inserts or myocardial insert (cardiac phantom; signal-to-background ratio [SBR], 10:1 or 5:1). In 25 positive and 38 negative patients (reference: endomyocardial biopsy or clinical diagnosis), Perugini scores and heart-to-contralateral (H/CL) count ratios were derived from planar images 1 hour and 3 hour p.i.

RESULTS

In phantom measurements, accuracy of myocardial CRpeak at SBR 10:1 (H-mode, 0.95-0.99) and reproducibility at 5:1 (H-mode, 1.02-1.14) was comparable for H-mode and L-mode. However, L-mode showed higher variability of background counts and sphere CRpeak throughout the field of view than H-mode. In patients, sensitivity/specificity were ≥ 95% for H/CL ratios at both time points and visual scoring 3 hour. At 1 hour, visual scores showed specificity of 89% and reduced reader's confidence.

CONCLUSIONS

Early DPD images provided no additional value for visual scoring or H/CL ratios. In SPECT/CT, H-mode is preferred over L-mode, especially if quantification is applied apart from the myocardium.

Detection of Bone Metastases on Bone Scans through Image Classification with Contrastive Learning

Patients with bone metastases have poor prognoses. A bone scan is a commonly applied diagnostic tool for this condition. However, its accuracy is limited by the nonspecific character of radiopharmaceutical accumulation, which indicates all-cause bone remodeling. The current study evaluated deep learning techniques to improve the efficacy of bone metastasis detection on bone scans, retrospectively examining 19,041 patients aged 22 to 92 years who underwent bone scans between May 2011 and December 2019. We developed several functional imaging binary classification deep learning algorithms suitable for bone scans. The presence or absence of bone metastases as a reference standard was determined through a review of image reports by nuclear medicine physicians. Classification was conducted with convolutional neural network-based (CNN-based), residual neural network (ResNet), and densely connected convolutional networks (DenseNet) models, with and without contrastive learning. Each set of bone scans contained anterior and posterior images with resolutions of 1024 × 256 pixels. A total of 37,427 image sets were analyzed. The overall performance of all models improved with contrastive learning. The accuracy, precision, recall, F1 score, area under the receiver operating characteristic curve, and negative predictive value (NPV) for the optimal model were 0.961, 0.878, 0.599, 0.712, 0.92 and 0.965, respectively. In particular, the high NPV may help physicians safely exclude bone metastases, decreasing physician workload, and improving patient care.

Metastatic Pulmonary Calcification Detected on 18F-FDG PET/CT and 99mTc-MDP Bone Scan

Metastatic calcification relates to abnormal calcification resulting from hypercalcemia and can affect soft tissues, skeletal muscle, myocardium, lungs, stomach, kidneys, and blood vessels. We describe a case of metastatic pulmonary calcification in a 71-year-old male, images with ¹⁸F-fluorodeoxyglucose (FDG) PET/CT and ^99mTc- methylene diphosphonate (MDP) bone scan.

Bone Scanning Findings in a Patient with Heat Stroke-Induced Rhabdomyolysis

We present a case that caused a diagnostic dilemma on a bone scan. We also review the broad spectrum of nonmalignant findings that can impact the interpretation of a bone scan and the value of correlative imaging using SPECT/CT for exact localization and characterization of lesions. The imaging features of important benign pathologies-that is, metastatic mimics-are elaborated so that the reader can avoid misinterpretations when reporting them. We elucidate 4 uncommon benign findings on a bone scan. Rhabdomyolysis is a result of lysis of skeletal muscle with release of cell contents, such as myoglobin and muscle enzymes, and is diagnosed mostly through a combination of clinical appearance and laboratory values. Myositis ossificans is the most common form of heterotopic ossification, usually occurring within large muscles. Its importance stems largely from its ability to mimic more aggressive pathologic processes. Myositis ossificans is one of the skeletal "do not touch" lesions. Such bone lesions are defined by characteristic imaging features, the identification of which precludes the need for additional diagnostic tests or biopsies, thereby avoiding unnecessary interventions. Acute tubular necrosis is kidney injury caused by damage to the kidney tubule cells (kidney cells that reabsorb fluid and minerals from urine as it forms). Common causes are low blood flow to the kidneys, drugs that damage the kidneys, or a severe underlying infection.

Can the Diagnostic Accuracy of Bone Scintigraphy be Maintained with Half the Scanning Time?

Purpose: We aim to show that the acquisition time of a conventional bone scan can be reduced by one-half without loss of the diagnostic value of the scan. Materials and Methods: Fifty adult patients (37 male and 13 female, mean age 62.5, SD 8.7 years) were enrolled. Patients were injected with 25-30 mCi (925-1110 MBq) ^99mTc MDP IV. The Standard Protocol whole body planar images were acquired first [scan speed = 10 cm/min, acquisition time around 20 minutes] and were followed immediately by the Half-Time Protocol whole body planar images [scan speed = 20 cm/min; acquisition time around 10 minutes]. Both images were interpreted by two nuclear medicine physicians. Each reviewer, when reviewing the Standard Protocol images, was "self-blinded" to the result they had obtained when reviewing the Half-Time images, and vice-versa. This self-blinding was accomplished by allowing a minimum of two weeks to elapse between the two interpretations. We used the κ-coefficient to compare the agreement between the Standard-Protocol results and the Half-Time results. Results: There was no difference in clinically significant diagnostic information for Half -Time and Standard Protocol. The diagnostic quality of Half-Time and the Standard Protocol images were not significantly different (0.86 < κ < 1.0). Conclusion: Our data suggest that if we reduce the ^99mTc MDP dose by half and keep the acquisition time at its standard value we gain the benefits of reduced dose without loss of diagnostic value of the scan.

Colorectal cancer with first known case of simultaneous bilateral tibial metastases

The most common osseous metastatic regions for colorectal cancer are the lumbar and sacral vertebrae and the pelvis. There are few reported cases of isolated solitary tibial metastasis, and simultaneous bilateral solitary tibial metastases in colorectal cancer are even rarer. A 62-year-old female patient was admitted to our inpatient clinic 3 years after receiving initial chemotherapy for a rectosigmoid adenocarcinoma with liver metastasis. The patient complained of left leg pain. Radiographs and magnetic resonance imaging revealed a 3- × 3-cm mass in the right proximal tibia and a 2- × 7-cm mass in the middle third of the left tibia; both were highly suggestive of bone metastases. Bilateral tibial metastases were confirmed after tumor excision and prophylactic open reduction and internal fixation. The postoperative course was relatively uneventful. Colorectal cancer with bone metastases is uncommon, and most metastases are found at a single site in an extremity. We believe this is the first published case of simultaneous bilateral tibial metastases in a patient with colorectal cancer.

A Radiological Scoring System for Differentiation between Enchondroma and Chondrosarcoma

Simple Summary

Background: It is challenging to differentiate between enchondromas and atypical cartilaginous tumors (ACTs)/chondrosarcomas. Methods: To evaluate the diagnostic usefulness of radiological findings for differentiation between enchondromas and chondrosarcomas, correlations between various radiological findings and final diagnoses were investigated. Based on the correlations, a scoring system combining these findings was developed. Results: In a cohort of 81 patients, periosteal reaction on X-ray, endosteal scalloping and cortical defect on CT, extraskeletal mass, multilobular lesion, abnormal signal in adjacent tissue on MRI, and increased uptake in bone scan and thallium scan was significantly correlated with final diagnoses. Based on the correlations, a radiological scoring system combining radiological findings was developed. In another cohort of 17 patients, the sensitivity, specificity, and accuracy of the radiological score rates for differentiation between enchondromas and chondrosarcomas were 88%, 89%, and 88%, respectively. Conclusion: Comprehensive assessment combining radiological findings is recommended to differentiate between enchondromas and ACTs/chondrosarcomas.

Abstract

Background: It is challenging to differentiate between enchondromas and atypical cartilaginous tumors (ACTs)/chondrosarcomas. In this study, correlations between radiological findings and final diagnosis were investigated in patients with central cartilaginous tumors. Methods: To evaluate the diagnostic usefulness of radiological findings, correlations between various radiological findings and final diagnoses were investigated in a cohort of 81 patients. Furthermore, a new radiological scoring system was developed by combining radiological findings. Results: Periosteal reaction on X-ray (p = 0.025), endosteal scalloping (p = 0.010) and cortical defect (p = 0.002) on CT, extraskeletal mass (p < 0.001), multilobular lesion (p < 0.001), abnormal signal in adjacent tissue (p = 0.004) on MRI, and increased uptake in bone scan (p = 0.002) and thallium scan (p = 0.027) was significantly correlated with final diagnoses. Based on the correlations between each radiological finding and postoperative histological diagnosis, a radiological scoring system combining these findings was developed. In another cohort of 17 patients, the sensitivity, specificity, and accuracy of the radiological score rates for differentiation between enchondromas and ACTs/chondrosarcomas were 88%, 89%, and 88%, respectively (p = 0.003). Conclusion: Radiological assessment with combined radiological findings is recommended to differentiate between enchondromas and ACT/chondrosarcomas.

Advantage of Hybrid 18F-Fluoride Positron Emission Tomography/Computed Tomography to Diagnose Malignant Rib Invasion by Pleural Metastasis in a Background of Reactive Periostitis

Diffuse osteoblastic activity in the ribs on bone scan is seen in association with pleural thickening. Irrespective of the pleural pathology, this represents benign finding caused by pleural hyperemia or reactive periostitis, with preserved cortical integrity. However, malignant involvement of the ribs can occur by local invasion of pleural malignancy causing cortical lysis. Herein, we describe the ¹⁸F-fluoride positron emission tomography/computed tomography findings of reactive periostitis of the ribs in pleural metastasis and emphasize the advantage of hybrid imaging in detecting local malignant tumor invasion superimposed in such condition.

Magnetic Resonance Imaging Signal Changes Mimicking Bone Metastasis in Patients Receiving Bisphosphonate Therapy

Bisphosphonates are inorganic pyrophosphate agents that reduce bone turnover. These agents reduce bone pain and delay skeletal complications, such as fractures in patients with metastatic lytic lesions, malignant-related hypercalcemia, multiple myeloma, Paget’s disease of bone, and osteoporosis. Osteonecrosis, developing in the jaw bones specifically, has been described as a complication associated with the use of bisphosphonates. In this report, we presented osteonecrosis-like magnetic resonance imaging findings that can be confused with bone metastasis in two patients who underwent long-term bisphosphonate treatment and the value of bone scan and ¹⁸flor-fluorodeoxyglucose positron emission tomography/computerized tomography in the differential diagnosis.

Cutaneous Metastases as Initial Presentation of Lung Carcinoma

Breast cancer, in women, and lung cancer, in men, are the most common origins of cutaneous metastasis. Lung cancer can metastasize to any organ but mostly to the contralateral lung, liver, adrenal gland, bones, and brain. Over 1-12% of patients with lung cancer can develop skin metastasis. Non-small cell lung cancer includes 87% of lung cancer cases. Adenocarcinomas subtype accounts for approximately 40% of all lung cancers and is the most common histology in women. A woman’s lifetime risk of developing lung cancer is 1 in 16 women but lower than that of a man (1 in 13 men). The survival rates of women with lung cancer are usually higher than those of men. Herein, we report the case of a 66-year-old female who presented with painless multiple skin nodules over the chest back and axilla for three months. On evaluation, biopsy and immunohistochemistry were done from skin nodules suggestive of adenocarcinoma. CT thorax showed lung mass and was diagnosed as a case of metastatic adenocarcinoma, primary being from the lung. Our case demonstrated that skin metastasis could be the first sign of internal malignancy. Metastasis to the skin is often a preterminal event that heralds a poor prognosis.