Multiparametric quantification of T1 and T2 relaxation time of bone metastasis in comparison with red or fatty bone marrow using magnetic resonance fingerprinting

OBJECTIVES

To assess the T1 and T2 values of bone marrow lesions in spine and pelvis derived from magnetic resonance fingerprinting (MRF) and to evaluate the differences in values among bone metastasis, red marrow and fatty marrow.

METHODS

Sixty patients who underwent lumbar spine and pelvic MRI with magnetic resonance fingerprinting were retrospectively included. Among eligible patients, those with bone metastasis, benign red marrow deposition and normal fatty marrow were identified. Two radiologists independently measured the T1 and T2 values from metastatic bone lesions, fatty marrow, and red marrow deposition on three-dimensional-magnetic resonance fingerprinting. Intergroup comparison and interobserver agreement were analyzed.

RESULTS

T1 relaxation time was significantly higher in osteoblastic metastasis than in red marrow (1674.6 ± 436.3 vs 858.7 ± 319.5, p < .001). Intraclass correlation coefficients for T1 and T2 values were 0.96 (p < 0.001) and 0.83 (p < 0.001), respectively. T2 relaxation time of osteoblastic metastasis and red marrow deposition had no evidence of a difference (osteoblastic metastasis, 57.9 ± 25.0 vs red marrow, 58.0 ± 34.4, p = 0.45), as were the average T2 values of osteolytic metastasis and red marrow deposition (osteolytic metastasis, 45.3 ± 15.1 vs red marrow, 58.0 ± 34.4, p = 0.63).

CONCLUSIONS

We report the feasibility of three-dimensional-magnetic resonance fingerprinting based quantification of bone marrow to differentiate bone metastasis from red marrow. Simultaneous T1 and T2 quantification of metastasis and red marrow deposition was possible in spine and pelvis and showed significant different values with excellent inter-reader agreement.

ADVANCE IN KNOWLEDGE

T1 values from three-dimensional-magnetic resonance fingerprinting might be a useful quantifier for evaluating bone marrow lesions.

Bone metastases from chondroblastoma: a rare pattern of metastatic disease in an adult

Chondroblastoma is a rare benign tumor, typically presenting in the first two decades. Systemic metastases in chondroblastoma are extremely rare and it is the rarity of these metastases which lead the World Health Organisation to re-classify this lesion from "intermediate" to "benign" in its updated classification of bone tumors in 2020. We present an unusual case of a 55 year-old male patient who presented with multiple FDG-avid bone lesions on a background of conventional chondroblastoma of the rib excised at another institution 11-years previously. Two of these lesions were also histologically-proven as conventional chondroblastoma at biopsy. This case highlights that, although rare, metastases can be seen in patients with chondroblastoma. To our knowledge, this is the only case with an unusual pattern of metastases limited to bone.

The significance of surveillance imaging in children with Ewing sarcoma and osteosarcoma

Primary bone tumors in children and adolescents, while rare, pose significant challenges in diagnosis and management. Children treated for Ewing sarcoma and osteosarcoma are offered a 5-year follow-up program after end of treatment, including radiological surveillance of primary location of tumor and the lungs. There is no consensus regarding how often and how the children should be followed with radiological imaging. This retrospective descriptive study of 69 patients (34 with Ewing sarcoma and 35 with osteosarcoma) investigated the consequences of abnormal findings in 1279 follow-up images. Nine relapses were detected, 4 in the Ewing group (3 local and 1 pulmonary) and 5 in the osteosarcoma group (1 local and 4 pulmonary). Of these, only two patients exhibited symptomatic relapses, with the remainder identified through imaging. The positive predictive value for relapse detection was 0.44 in the Ewing group, and 0.5 in the osteosarcoma group. In the Ewing sarcoma patient image follow-up program, the probability of anomaly detection was 12% (95% CI, 10-15). For osteosarcoma patients, the likelihood was 6% (95% CI, 4-8). Our data indicates that abnormal findings on follow-up images rarely represents relapse of tumor. As the surveillance protocol differs between the patient groups, wherein Ewing sarcoma patients primarily are monitored through MRI while osteosarcoma patients are predominantly tracked via X-rays, there is an increased occurrence of incidental findings in the first group. However, it is imperative to interpret imaging data in conjunction with clinical information, avoiding isolated reliance on imaging results when making treatment decisions.

Uptake of 99m Tc-DTPA in Bone Metastases From Follicular Thyroid Carcinoma

ABSTRACT

A 53-year-old man with follicular thyroid carcinoma (FTC) was referred for renal scintigraphy using 99m Tc-DTPA to assess the kidney function. Unexpectedly, the images showed an abnormal uptake of radiotracer in the right pelvic region. It corresponded to the site of metastasis in the right ilium revealed on 131 I SPECT/CT images. The biopsy pathology of the ilium lesion demonstrated follicular thyroid cancer.

Desmoplastic fibroma in a child: a 9-year follow-up case report

BACKGROUND

Desmoplastic fibroma is an extremely rare primary bone tumor. Its characteristic features include bone destruction accompanied by the formation of soft tissue masses. This condition predominantly affects individuals under the age of 30. Since its histology is similar to desmoid-type fibromatosis, an accurate diagnosis before operation is difficult. Desmoplastic fibroma is resistant to chemotherapy, and the efficacy of radiotherapy is uncertain. Surgical excision is preferred for treatment, but it entails high recurrence. Further, skeletal reconstruction post-surgery is challenging, especially in pediatric cases.

CASE PRESENTATION

Nine years ago, a 14-year-old male patient presented with a 4-year history of progressive pain in his left wrist. Initially diagnosed as fibrous dysplasia by needle biopsy, the patient underwent tumor resection followed by free vascularized fibular proximal epiphyseal transfer for wrist reconstruction. However, a histological examination confirmed a diagnosis of desmoplastic fibroma. The patient achieved bone union and experienced a recurrence in the ipsilateral ulna 5 years later, accompanied by a wrist deformity. He underwent a second tumor resection and wrist arthrodesis in a single stage. The most recent annual follow-up was in September 2023; the patient had no recurrence and was satisfied with the surgery.

CONCLUSIONS

Desmoplastic fibroma is difficult to diagnose and treat, and reconstruction surgery after tumor resection is challenging. Close follow-up by experienced surgeons may be beneficial for prognosis.

A CT-based radiomics nomogram for predicting histologic grade and outcome in chondrosarcoma

OBJECTIVE

The preoperative identification of tumor grade in chondrosarcoma (CS) is crucial for devising effective treatment strategies and predicting outcomes. The study aims to build and validate a CT-based radiomics nomogram (RN) for the preoperative identification of tumor grade in CS, and to evaluate the correlation between the RN-predicted tumor grade and postoperative outcome.

METHODS

A total of 196 patients (139 in the training cohort and 57 in the external validation cohort) were derived from three different centers. A clinical model, radiomics signature (RS) and RN (which combines significant clinical factors and RS) were developed and validated to assess their ability to distinguish low-grade from high-grade CS with area under the curve (AUC). Additionally, Kaplan-Meier survival analysis was applied to examine the association between RN-predicted tumor grade and recurrence-free survival (RFS) of CS. The predictive accuracy of the RN was evaluated using Harrell's concordance index (C-index), hazard ratio (HR) and AUC.

RESULTS

Size, endosteal scalloping and active periostitis were selected to build the clinical model. Three radiomics features, based on CT images, were selected to construct the RS. Both the RN (AUC, 0.842) and RS (AUC, 0.835) were superior to the clinical model (AUC, 0.776) in the validation set (P = 0.003, 0.040, respectively). A correlation between Nomogram score (Nomo-score, derived from RN) and RFS was observed through Kaplan-Meier survival analysis in the training and test cohorts (log-rank P < 0.050). Patients with high Nomo-score tumors were 2.669 times more likely to suffer recurrence than those with low Nomo-score tumors (HR, 2.669, P < 0.001).

CONCLUSIONS

The CT-based RN performed well in predicting both the histologic grade and outcome of CS.

Osteochondrolipoma of the foot treated by surgical excision: a case report and literature review

BACKGROUND

Osteochondromas, classified as a new benign subtype of lipomas and characterised by chondroid and osseous differentiation, are rare lesions that have been infrequently reported in previous literature. The maxillofacial region was reported as the most frequent localization, with infrequent occurrence in the lower limb. This paper represents the first documented case report of osteochondrolipoma in the foot.

CASE PRESENTATION

A 51-year-old male patient presented with a chief complaint of right foot pain at the plantar aspect, accompanied by the observation of swelling between the first and the second metatarsal shafts. His complaint of pain and swelling started 10 and 4 years prior, respectively. Since their onset, both symptoms have progressed in nature. Imaging revealved a large mass exhibiting a nonhomogenous composition of fibrous tissue and bony structures. Surgical intervention through total excision was indicated.

CONCLUSION

Osteochodrolipoma is a benign lesion that can affect the foot leading to decreased functionality of the foot due to the pain and swelling. Surgical excision is the recommended approach for this lesion, providing both symptomatic relief and confirmation of the diagnosis through histopathological examination.

Osteosarcoma-targeted Cu and Ce based oxide nanoplatform for NIR II fluorescence/magnetic resonance dual-mode imaging and ros cascade amplification along with immunotherapy

BACKGROUND

As the lethal bone tumor, osteosarcoma often frequently occurs in children and adolescents with locally destructive and high metastasis. Distinctive kinds of nanoplatform with high therapeutical effect and precise diagnosis for osteosarcoma are urgently required. Multimodal optical imaging and programmed treatment, including synergistic photothermal-chemodynamic therapy (PTT-CDT) elicits immunogenetic cell death (ICD) is a promising strategy that possesses high bio-imaging sensitivity for accurate osteosarcoma delineating as well as appreciable therapeutic efficacy with ignorable side-effects.

METHODS AND RESULTS

In this study, mesoporous Cu and Ce based oxide nanoplatform with Arg-Gly-Asp (RGD) anchoring is designed and successfully constructed. After loading with indocyanine green, this nanoplatform can be utilized for precisely targeting and efficaciously ablating against osteosarcoma via PTT boosted CDT and the closely following ICD stimulation both in vitro and in vivo. Besides, it provides off-peak fluorescence bio-imaging in the second window of near-infrared region (NIR II, 1000-1700 nm) and Magnetic resonance signal, serves as the dual-mode contrast agents for osteosarcoma tissue discrimination.

CONCLUSION

Tumor targeted Cu&Ce based mesoporous nanoplatform permits efficient osteosarcoma suppression and dual-mode bio-imaging that opens new possibility for effectively diagnosing and inhibiting the clinical malignant osteosarcoma.

Osteoid osteoma of the distal radius presenting as an inconspicuous swelling in a young child

Osteoid osteoma is a benign osteoblastic tumour with a predilection for the lower extremity that rarely affects the forearm. It is commonly seen in adolescents and young adults, and is seldom diagnosed in the paediatric age group. We report a boy in his early childhood who presented with a swelling over the distal forearm, which was incidentally noted by the mother 3 months ago. Plain radiographs showed diffuse sclerosis of the dorsal cortex of the distal radius. CT scan showed a central lucent nidus in the intramedullary region and surrounding sclerosis in the radial metaphysis, confirming the diagnosis of osteoid osteoma. The patient was successfully treated by surgical en bloc resection of the nidus and was asymptomatic at 1-year follow-up. Non-specific symptoms at presentation make it a challenge to diagnose osteoid osteoma in children and it needs to be considered in the differential diagnosis when radiographs show lytic lesions in the bone.

Comparative Study of Different Imaging Modalities for Diagnosis of Bone Metastases of Prostate Cancer: A Bayesian Network Meta-analysis

PURPOSE

This study aimed to compare the diagnostic performances of 8 different imaging modalities for preoperative detection of bone metastases in prostate cancer patients by performing a network meta-analysis using direct comparison studies with 2 or more imaging techniques.

PATIENTS AND METHODS

We searched PubMed, Embase, and Cochrane Library for studies evaluating the performances of 8 different imaging modalities for the preoperative detection of bone metastases in prostate cancer patients. The network meta-analysis was performed in patient-based analysis. The consistency was evaluated by examining the agreement between direct and indirect treatment effects, and the surface under the cumulative ranking curve (SUCRA) values were obtained to calculate the probability of each imaging modality being the most effective diagnostic method.

RESULTS

A total of 999 patients from 13 direct comparison studies using 8 different imaging modalities for preoperative detection or follow-up of bone metastases in prostate cancer patients were included. For the detection of bone metastases of prostate cancer, 68 Ga-PSMA-11 PET/CT showed the highest SUCRA values of sensitivity, positive predictive value, accuracy, and diagnostic odds ratio. In addition, 18 F-NaF PET/CT and SPECT/CT showed high SUCRA values.

CONCLUSIONS

68 Ga-PSMA-11 PET/CT showed the highest SUCRA values. Other imaging modalities showed complementary diagnostic roles for preoperative detection of bone metastases in patients with prostate cancer, except bone scintigraphy and MRI.

FDG-Avid Periprosthetic Particle Disease Mimicking Osteosarcoma Recurrence

ABSTRACT

A 24-year-old man with a history of osteosarcoma presented with swelling in his right thigh for more than 1 year. 18 F-FDG PET/CT demonstrated increased FDG uptake in multiple juxtacortical masses around the prosthesis, which highly suggested the possibility of osteosarcoma recurrence. A biopsy was performed, and the pathology confirmed the diagnosis of particle disease. The current case indicates that particle disease should be considered when interpreting the PET/CT images with high FDG uptake around the prosthesis.

Therapeutic efficacy of an alpha-particle emitter labeled anti-GD2 humanized antibody against osteosarcoma-a proof of concept study

PURPOSE

Current treatments for osteosarcoma (OS) have a poor prognosis, particularly for patients with metastasis and recurrence, underscoring an urgent need for new targeted therapies to improve survival. Targeted alpha-particle therapy selectively delivers cytotoxic payloads to tumors with radiolabeled molecules that recognize tumor-associated antigens. We have recently demonstrated the potential of an FDA approved, humanized anti-GD2 antibody, hu3F8, as a targeted delivery vector for radiopharmaceutical imaging of OS. The current study aims to advance this system for alpha-particle therapy of OS.

METHODS

The hu3F8 antibody was radiolabeled with actinium-225, and the safety and therapeutic efficacy of the [225Ac]Ac-DOTA-hu3F8 were evaluated in both orthotopic murine xenografts of OS and spontaneously occurring OS in canines.

RESULTS

Significant antitumor activity was proven in both cases, leading to improved overall survival. In the murine xenograft's case, tumor growth was delayed by 16-18 days compared to the untreated cohort as demonstrated by bioluminescence imaging. The results were further validated with magnetic resonance imaging at 33 days after treatment, and microcomputed tomography and planar microradiography post-mortem. Histological evaluations revealed radiation-induced renal toxicity, manifested as epithelial cell karyomegaly and suggestive polyploidy in the kidneys, suggesting rapid recovery of renal function after radiation damage. Treatment of the two canine patients delayed the progression of metastatic spread, with an overall survival time of 211 and 437 days and survival beyond documented metastasis of 111 and 84 days, respectively.

CONCLUSION

This study highlights the potential of hu3F8-based alpha-particle therapy as a promising treatment strategy for OS.

CT and MR imaging findings of head and neck chondrosarcoma

OBJECTIVES

This study investigated the imaging features of head and neck chondrosarcoma (HNCS) according to its origin and pathologic subtype.

METHODS

Patients who were pathologically diagnosed with HNCS between January 2000 and April 2022 were retrospectively reviewed. Lesions were classified based on their origin and pathologic subtype. The size and margin were evaluated on the image. Internal calcification and the effects on adjacent bone were assessed using computed tomography (CT) images, while signal intensity and contrast enhancement patterns were analyzed using magnetic resonance (MR) imaging.

RESULTS

Thirteen HNCSs were included in this study: 8 bone tumors (61.5%) and 5 soft tissue tumors (38.5%). The bone tumors were pathologically diagnosed as conventional (n = 5) and mesenchymal type (n = 3). Soft tissue tumors were defined as myxoid type. The main symptoms were swelling (90.9%) and pain (72.7%). The lesions measured 4.5 cm on average. The margins showed benign and well-defined except for the mesenchymal type. On CT, most bone tumors (75%) showed internal calcification with remodeling or destruction of the adjacent bone. No soft tissue tumors, except one case, showed internal calcification or destruction of the adjacent bone. MR imaging features were non-specific (T2 high signal intensity and contrast enhancement).

CONCLUSIONS

HCNS showed various imaging findings according to their origin and pathologic subtype. HNCS should be differentiated if a bone tumor shows internal calcification and affects the adjacent bone. When diagnosing slow-growing soft tissue tumors, even if low possibility, HNCS should be considered.

Can 18F-FES PET Improve the Evaluation of 18F-FDG PET in Patients With Metastatic Invasive Lobular Carcinoma?

PURPOSE

Invasive lobular carcinoma (ILC) exhibits a low affinity for 18F-FDG. The estrogen receptor (ER) is commonly expressed in ILCs, suggesting a potential benefit of targeting with the ER probe 18F-FES in this patient population. The objective of this study was to evaluate the diagnostic performance of 18F-FES imaging in patients with metastatic ILC and compare it with that of 18F-FDG.

METHODS

We conducted a retrospective analysis of 20 ILC patients who underwent concurrent 18F-FES and 18F-FDG PET/CT examinations in our center. 18F-FES and 18F-FDG imaging were analyzed to determine the total count of tracer-avid lesions in nonbone sites and their corresponding organ systems, assess the extent of anatomical regions involved in bone metastases, and measure the SUVmax values for both tracers.

RESULTS

Among 20 ILC patients, 65 nonbone lesions were found to be distributed in 13 patients, and 16 patients were diagnosed with bone metastasis, which was distributed in 54 skeletal anatomical regions. The detection rate of 18F-FDG in nonbone lesions was higher than that of 18F-FES (57 vs 37, P < 0.001). 18F-FES demonstrated a superior ability to detect nonbone lesions in 4 patients, whereas 18F-FDG was superior in 5 patients (P > 0.05). Among 9/16 patients with bone metastasis, 18F-FES demonstrated a significant advantage in the detection of bone lesions compared with 18F-FDG (P = 0.05). Furthermore, patients with only 18F-FES-positive lesions (12/12) were administered endocrine regimens, whereas patients lacking 18F-FES uptake (2/3) predominantly received chemotherapy.

CONCLUSIONS

18F-FES is more effective than 18F-FDG in detecting bone metastasis in ILC, but it does not demonstrate a significant advantage in nonbone lesions. Additionally, the results of examination with 18F-FES have the potential to guide patient treatment plans.

A machine learning radiomics model based on bpMRI to predict bone metastasis in newly diagnosed prostate cancer patients

OBJECTIVES

To develop and evaluate a machine learning radiomics model based on biparametric magnetic resonance imaging MRI (bpMRI) to predict bone metastasis (BM) status in newly diagnosed prostate cancer (PCa) patients.

METHODS

We retrospectively analyzed bpMRI scans of PCa patients from multiple centers between January 2016 and October 2021. 348 PCa patients were recruited from two institutions for this study. The first institution contributed 284 patients, stratified and randomly divided into training and internal validation cohorts at a 7:3 ratio. The remaining 64 patients were sourced from the second institution and comprised the external validation cohort. Radiomics features were extracted from axial T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) tumor regions. We developed the radiomics prediction model for BM in the training cohort and validated it in the internal and external validation cohorts. As a benchmark, we trained the logistic regression model with lasso feature reduction (LFR-LRM) in the training cohort and further compared it with Naive Bayes, eXtreme Gradient Boosting (XGboost), Random Forest (RF), GBDT, SVM, Adaboost, and KNN algorithms and validated in both the internal and external cohorts. The performance of several predictive models was assessed by receiver operating characteristic (ROC).

RESULTS

The LFR-LRM model achieved an area under the receiver operating characteristic curve (AUC) of 0.89 (95% CI: 0.822-0.974) and an accuracy of 0.828 (95% CI: 0.713-0.911). The AUC and accuracy in external validation were 0.866 (95% CI: 0.784-0.948) and 0.769 (95% CI: 0.648-0.864), respectively. The RF and XGBoost models outperformed the LFR-LRM, with AUCs of 0.907 (95% CI: 0.863-0.949) and 0.928 (95% CI: 0.882-0.974) and accuracies of 0.831 (95% CI: 0.727-0.907) and 0.884 (95% CI: 0.792-0.946). External validation for these models yielded AUCs and accuracies of 0.911 (95% CI: 0.861-0.966), 0.921 (95% CI: 0.889-0.953), and 0.846 (95% CI: 0.735-0.923) and 0.876 (95% CI: 0.771-0.945), respectively.

CONCLUSIONS

The XGboost machine learning model is more accurate than LFR-LRM for predicting BM in patients with newly confirmed PCa.

Time-Driven Activity-Based Cost Comparison of Osteoid Osteoma Ablation Techniques

OBJECTIVE

Compare the cost of performing an osteoid osteoma ablation using cone beam CT (CBCT) with overlay fluoroscopic guidance to ablation using conventional CT (CCT) guidance and microwave ablation (MWA) to radiofrequency ablation (RFA).

METHODS

An 11-year retrospective study was performed of all patients undergoing osteoid osteoma ablation. Ablation equipment included a Cool tip RFA probe (Covidien, Minneapolis, Minnesota) or a Neuwave PR MWA probe (Ethicon, Rariton, New Jersey). The room times as well as immediate recovery time were recorded for each case. Cost analysis was then performed using time-driven activity-based costing for rate-dependent variables including salaries, equipment depreciation, room time, and certain supplies. Time-independent costs included the disposable interventional radiology supplies and ablation systems. Costs were reported for each service providing care and using conventional cost accounting methods with variable and fixed expenditures.

RESULTS

A total of 91 patients underwent 96 ablation procedures in either CBCT (n = 66) or CCT (n = 30) using either MWA (n = 51) or RFA (n = 45). The anesthesia induction (22.7 ± 8.7 min versus 15.9 ± 7.2 min, P < .001), procedure (64.7 ± 27.5 min versus 47.3 ± 15.3 min; P = .001), and room times (137.7 ± 33.7 min versus 103.9 ± 22.6. min; P < .001) were significantly longer for CBCT procedures. The procedure time did not differ significantly between MWA and RFA (62.1 ± 27.4 min versus 56.1 ± 23.3 min; P = .27). Multiple regression analysis demonstrated lower age (P = .046), CBCT use (P = .001), RFA use (P = .02), and nonsupine patient position (P = .01) significantly increased the total procedural cost. After controlling for these variables, the total cost of CBCT ($5,981.32 ± $523.93 versus $5,378.93 ± $453.12; P = .001) remained higher than CCT and the total cost of RFA ($5,981.32 ± $523.93 versus $5,674.43 ± $549.14; P = .05) approached a higher cost than MWA.

CONCLUSION

The use of CBCT with overlay fluoroscopic guidance for osteoid osteoma ablation resulted in longer in-room times and greater cost when compared with CCT. These cost considerations should be weighed against potential radiation dose advantage of CBCT when choosing an image guidance modality. Younger age, RFA use, and nonsupine patient position additionally contributed to higher costs.

Positron Emission Tomography/Computed Tomography Transformation of Oncology: Musculoskeletal Cancers

The past 25 years have seen significant growth in the role of positron emission tomography/computed tomography (PET/CT) in musculoskeletal oncology. Substantiative advances in technical capability and image quality have been paralleled by increasingly widespread clinical adoption and implementation. It is now recognized that PET/CT is useful in diagnosis, staging, prognostication, response assessment, and surveillance of bone and soft tissue sarcomas, often providing critical information in addition to conventional imaging assessment. As individualized, precision medicine continues to evolve for patients with sarcoma, PET/CT is uniquely positioned to offer additional insight into the biology and management of these tumors.

Automated Detection and Segmentation of Bone Metastases on Spine MRI Using U-Net: A Multicenter Study

OBJECTIVE

To develop and evaluate a deep learning model for automated segmentation and detection of bone metastasis on spinal MRI.

MATERIALS AND METHODS

We included whole spine MRI scans of adult patients with bone metastasis: 662 MRI series from 302 patients (63.5 ± 11.5 years; male:female, 151:151) from three study centers obtained between January 2015 and August 2021 for training and internal testing (random split into 536 and 126 series, respectively) and 49 MRI series from 20 patients (65.9 ± 11.5 years; male:female, 11:9) from another center obtained between January 2018 and August 2020 for external testing. Three sagittal MRI sequences, including non-contrast T1-weighted image (T1), contrast-enhanced T1-weighted Dixon fat-only image (FO), and contrast-enhanced fat-suppressed T1-weighted image (CE), were used. Seven models trained using the 2D and 3D U-Nets were developed with different combinations (T1, FO, CE, T1 + FO, T1 + CE, FO + CE, and T1 + FO + CE). The segmentation performance was evaluated using Dice coefficient, pixel-wise recall, and pixel-wise precision. The detection performance was analyzed using per-lesion sensitivity and a free-response receiver operating characteristic curve. The performance of the model was compared with that of five radiologists using the external test set.

RESULTS

The 2D U-Net T1 + CE model exhibited superior segmentation performance in the external test compared to the other models, with a Dice coefficient of 0.699 and pixel-wise recall of 0.653. The T1 + CE model achieved per-lesion sensitivities of 0.828 (497/600) and 0.857 (150/175) for metastases in the internal and external tests, respectively. The radiologists demonstrated a mean per-lesion sensitivity of 0.746 and a mean per-lesion positive predictive value of 0.701 in the external test.

CONCLUSION

The deep learning models proposed for automated segmentation and detection of bone metastases on spinal MRI demonstrated high diagnostic performance.

Biomimetic design and clinical application of Ti-6Al-4V lattice hemipelvis prosthesis for pelvic reconstruction

OBJECTIVE

This study aims to biomimetic design a new 3D-printed lattice hemipelvis prosthesis and evaluate its clinical efficiency for pelvic reconstruction following tumor resection, focusing on feasibility, osseointegration, and patient outcomes.

METHODS

From May 2020 to October 2021, twelve patients with pelvic tumors underwent tumor resection and subsequently received 3D-printed lattice hemipelvis prostheses for pelvic reconstruction. The prosthesis was strategically incorporated with lattice structures and solid to optimize mechanical performance and osseointegration. The pore size and porosity were analyzed. Patient outcomes were assessed through a combination of clinical and radiological evaluations.

RESULTS

Multiple pore sizes were observed in irregular porous structures, with a wide distribution range (approximately 300-900 μm). The average follow-up of 34.7 months, ranging 26 from to 43 months. One patient with Ewing sarcoma died of pulmonary metastasis 33 months after surgery while others were alive at the last follow-up. Postoperative radiographs showed that the prosthesis's position was consistent with the preoperative planning. T-SMART images showed that the host bone was in close and tight contact with the prosthesis with no gaps at the interface. The average MSTS score was 21 at the last follow-up, ranging from 18 to 24. There was no complication requiring revision surgery or removal of the 3D-printed hemipelvis prosthesis, such as infection, screw breakage, and prosthesis loosening.

CONCLUSION

The newly designed 3D-printed lattice hemipelvis prosthesis created multiple pore sizes with a wide distribution range and resulted in good osteointegration and favorable limb function.

Machine learning based on SPECT/CT to differentiate bone metastasis and benign bone lesions in lung malignancy patients

BACKGROUND

Bone metastasis is a common event in lung cancer progression. Early diagnosis of lung malignant tumor with bone metastasis is crucial for selecting effective treatment strategies. However, 14.3% of patients are still difficult to diagnose after SPECT/CT examination.

PURPOSE

Machine learning analysis of [99mTc]-methylene diphosphate (99mTc-MDP) SPECT/CT scans to distinguish bone metastases from benign bone lesions in patients with lung cancer.

METHODS

One hundred forty-one patients (69 with bone metastases and 72 with benign bone lesions) were randomly assigned to the training group or testing group in a 7:3 ratio. Lesions were manually delineated using ITK-SNAP, and 944 radiomics features were extracted from SPECT and CT images. The least absolute shrinkage and selection operator (LASSO) regression was used to select the radiomics features in the training set, and the single/bimodal radiomics models were established based on support vector machine (SVM). To further optimize the model, the best bimodal radiomics features were combined with clinical features to establish an integrated Radiomics-clinical model. The diagnostic performance of models was evaluated using receiver operating characteristic (ROC) curve and confusion matrix, and performance differences between models were evaluated using the Delong test.

RESULTS

The optimal radiomics model comprised of structural modality (CT) and metabolic modality (SPECT), with an area under curve (AUC) of 0.919 and 0.907 for the training and testing set, respectively. The integrated model, which combined SPECT, CT, and two clinical features, exhibited satisfactory differentiation in the training and testing set, with AUC of 0.939 and 0.925, respectively.

CONCLUSIONS

The machine learning can effectively differentiate between bone metastases and benign bone lesions. The Radiomics-clinical integrated model demonstrated the best performance.

Quarter-Century Transformation of Oncology: Positron Emission Tomography for Patients with Breast Cancer

PET radiotracers have become indispensable in the care of patients with breast cancer. 18F-fluorodeoxyglucose has become the preferred method of many oncologists for systemic staging of breast cancer at initial diagnosis, detecting recurrent disease, and for measuring treatment response after therapy. 18F-Sodium Fluoride is valuable for detection of osseous metastases. 18F-fluoroestradiol is now FDA-approved with multiple appropriate clinical uses. There are multiple PET radiotracers in clinical trials, which may add utility of PET imaging for patients with breast cancer in the future. This article will describe the advances during the last quarter century in PET for patients with breast cancer.

The clinical significance of indeterminate pulmonary nodules in patients with primary bone sarcoma: a systematic review

OBJECTIVE

To report the incidence of indeterminate pulmonary nodules (IPN) and the rate of progression of IPNs to metastasis in patients with primary bone cancers. We also aimed to evaluate clinical or radiological parameters that may identify IPNs more likely to progress to metastatic disease and their effect on overall or event-free survival in patients with primary bone sarcoma.

METHODS

A systematic search of the electronic databases Medline, Embase, and Cochrane Library was undertaken for eligible articles on IPNs in patients with primary bone sarcomas, published in the English language from inception of the databases to 2023. The Newcastle-Ottawa Quality Assessment Form for Cohort Studies was utilized to evaluate risk of bias in included studies.

RESULTS

Six studies, involving 1667 patients, were included in this systematic review. Pooled quantitative analysis found the rate of incidence of IPN to be 18.1% (302 out of 1667) and the rate of progression to metastasis to be 45.0% (136 out of 302). Nodule size (more than 5 mm diameter), number (more than or equal to 4), distribution (bilaterally distributed), incomplete calcification, and lobulated margins were associated with an increased likelihood of IPNs progressing to metastasis, however, their impact on overall or event-free survival remains unclear.

CONCLUSION

The risk of IPNs progressing to metastasis in patients with primary bone sarcoma is non-negligible. Large IPNs have a high risk to be an actual metastasis. We suggest that IPNs in these patients be followed up for a minimum of 2 years with CT imaging at 3, 6, and 12 month intervals, particularly for nodules measuring >5 mm in average diameter.

ADVANCES IN KNOWLEDGE

This is the first systematic review on IPNs in patients with primary bone sarcomas only and proposes viable management strategies for such patients.

The CT and MRI features of benign calvarium and skull base osteoblastoma

OBJECTIVE

We retrospectively reviewed the CT and MRI features of patients with benign osteoblastoma in the calvarium and skull base (CSBOB).

METHODS

Nine cases of pathologically confirmed benign CSBOB were analysed retrospectively. The patients had undergone CT and/or MRI. Tumour location, size, and imaging features were reviewed and recorded.

RESULTS

The patients included four males and five females with a mean age of 27.0 years (age 14-40 years). The tumours were located in the frontal bone in 3 patients, the occipital bone in 3 patients, and in the parietal bone, sphenoid bone, and skull base in 1 patient each. On CT, the tumours measured 5.1 ± 3.3 (1.8-8.4) cm. Seven tumours were shown to have caused expansile bony destruction with an eggshell appearance and varying degrees of calcification or matrix mineralization. Multiple septa were observed in 5 tumours. Intracranial growth was observed in 5 tumours. On MRI, 7 tumours showed heterogeneous hypo- to isointensity on T1WI. Heterogeneous high signal patterns with low signal rims and septa were observed in 6 tumours on T2WI, and 4 showed a fluid-fluid level. On contrast-enhanced imaging, 6 tumours showed peripheral and septal enhancement, and 2 showed the dural tail sign.

CONCLUSIONS

Benign CSBOB is a rare tumour characterized by expansile bony destruction, septa, a sclerotic rim and calcification or matrix mineralization on CT and MRI.

ADVANCES IN KNOWLEDGE

The findings from this study contribute to a better understanding of benign CSBOB and provide valuable imaging features that can aid in its diagnosis and differentiation from other tumours in the calvarium and skull base.

Intraosseous myolipoma of the calcaneus

A man in his 40s presented with an incidental finding of an osteolytic bone lesion. He sustained an ankle injury while inline skating, fracturing his lateral malleolus. Besides the fracture, radiographic imaging on the day of the injury incidentally revealed a well-defined solitary osteolytic lesion with a sclerotic rim within the right calcaneus. MRI showed an intraosseous, fat-containing lesion with focal contrast enhancement, assessed as an intraosseous lipoma with central necrosis. In the pathological analysis of a sample of the lesion an intraosseous myolipoma of the calcaneus was found-an unexpected and extraordinary finding. To prevent pathological fracturing, curettage and bone grafting were performed using autologous iliac crest bone in combination with allogenous bone chips.

An innovative reconstruction of an enbloc resected composite giant chest and abdominal wall chondrosarcoma with 3D-composite mesh

BACKGROUND

Chest wall chondrosarcomas, although common, pose unique challenges due to their aggressive nature, rarity of abdominal wall involvement, and propensity for recurrence. We highlight the critical role of meticulous surgical planning, multidisciplinary collaboration, and innovative reconstruction techniques in achieving optimal outcomes for patients with composite giant chest and abdominal wall chondrosarcoma.

CASE PRESENTATION

A 38-year-old female patient presented with progressive left chest and abdominal wall swelling for two years; on evaluation had a large lobulated lytic lesion arising from the left ninth rib, scalloping eighth and tenth ribs measuring 13.34 × 8.92 × 10.71 cm (anteroposterior/transverse/craniocaudal diameter) diagnosed with chondrosarcoma grade 2. A three-dimensional (3D) composite mesh was designed based on computed tomography using virtual surgical planning and computer-assisted design and manufacturing technology. She underwent wide local excision and reconstruction of the chest and abdominal wall with 3D-composite mesh under general anesthesia. The postoperative condition was uneventful, with no recurrence at 12 months follow-up.

CONCLUSION

A 3D-composite mesh facilitates patient-specific, durable, and cost-effective chest and abdominal wall reconstruction.

Osteoid osteoma presenting with scoliosis: successful resection with endoscopic excision

A young male in his mid-teen years presented with severe back pain for 3 months and was subsequently diagnosed with osteoid osteoma in the left superior articular process of the L4 vertebra. Initial treatment with non-steroidal anti-inflammatory drugs provided temporary relief. Due to concerns about scoliosis progression along with unrelieved pain, a multidisciplinary team recommended endoscopic excision of the osteoid osteoma. The procedure resulted in complete pain relief and an improvement in the scoliosis curve from 22° of Cobb's angle to 12 degrees at the 8-month follow-up.

18F-FDG PET/CT and 99mTc-MDP Bone Scintigraphy Findings of Multifocal Desmoid Fibromatosis

ABSTRACT

Desmoid fibromatosis, also called desmoid tumors, is a group of locally aggressive fibromatous proliferative disorders. They represent less than 3% of all soft tissue sarcoma and are multifocal in approximately 10% of cases. However, there are only a few cases in the literature describing 18F-FDG PET/CT and 99mTc-MDP bone scan features of extra-abdominal desmoid fibromas, and all were solitary bone lesions. Herein, we presented a unique case of multifocal desmoid fibromatosis of bone illustrating the prospective value of 18F-FDG PET/CT and 99mTc-MDP bone scan in the evaluation of desmoid tumors.

Risk factors for rib metastases of lung cancer patients with high-uptake rib foci on 99Tcm-MDP SPECT/CT

BACKGROUND

99Tcm-MDP SPECT/CT is widely used to diagnose early bone metastasis. Ribs are high-risk bone metastasis sites, while few study is related to ribs. The study is to investigate the risk factors of rib metastases in lung cancer patients.

METHODS

We retrospectively analyzed the patients' clinical characteristics and SPECT/CT imaging features. The patients were divided into a rib metastasis group (108 cases) and a non-rib metastasis group (103 cases).

RESULTS

In 211 patients, rib metastases were closely related to tumor markers, T stage, N stage, clinical staging, lymph node (LN) involvement, number of rib foci, localization on rib and foci type (P<0.05). In 93 patients with pure rib foci, rib metastases were affected by clinical staging, LN involvement, localization on the rib and primary lung cancer localization (P<0.001, 0.038,<0.001, 0.034, respectively). In 100 patients with a solitary rib focus, rib metastases were associated with clinical staging, localization on the rib, and LN involvement (P<0.001, 0.001, and 0.014, respectively). In all 633 rib foci, localization on the rib was an effective risk factor for rib metastases (P<0.001).

CONCLUSIONS

Patients with increased tumor markers, stage IV lung adenocarcinoma and multiple rib foci located ipsilaterally with the primary lung tumor, or rib foci accompanied other bone foci are more likely to develop rib metastasis. Patients with pure rib foci or a solitary rib focus, especially in the anterior rib with negative LN involvement, have a low probability of rib metastasis.

Verification of image quality improvement of low-count bone scintigraphy using deep learning

To improve image quality for low-count bone scintigraphy using deep learning and evaluate their clinical applicability. Six hundred patients (training, 500; validation, 50; evaluation, 50) were included in this study. Low-count original images (75%, 50%, 25%, 10%, and 5% counts) were generated from reference images (100% counts) using Poisson resampling. Output (DL-filtered) images were obtained after training with U-Net using reference images as teacher data. Gaussian-filtered images were generated for comparison. Peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) to the reference image were calculated to determine image quality. Artificial neural network (ANN) value, bone scan index (BSI), and number of hotspots (Hs) were computed using BONENAVI analysis to assess diagnostic performance. Accuracy of bone metastasis detection and area under the curve (AUC) were calculated. PSNR and SSIM for DL-filtered images were highest in all count percentages. BONENAVI analysis values for DL-filtered images did not differ significantly, regardless of the presence or absence of bone metastases. BONENAVI analysis values for original and Gaussian-filtered images differed significantly at ≦25% counts in patients without bone metastases. In patients with bone metastases, BSI and Hs for original and Gaussian-filtered images differed significantly at ≦10% counts, whereas ANN values did not. The accuracy of bone metastasis detection was highest for DL-filtered images in all count percentages; the AUC did not differ significantly. The deep learning method improved image quality and bone metastasis detection accuracy for low-count bone scintigraphy, suggesting its clinical applicability.

Detectability of cold tumors by xSPECT bone technology compared with hot tumors: a supine phantom study

Detecting cold as well as hot tumors is vital for interpreting bone tumors on single-photon emission computed tomography (SPECT) images. This study aimed to visually and quantitatively demonstrate the detectability of cold tumors using xSPECT technology compared with that of hot tumors in the phantom study. Five tumors of different sizes and normal bone contained a mixture of 99mTc and K2HPO4 in a spine phantom. We acquired SPECT data using an xSPECT protocol and transverse images were reconstructed using xSPECT Bone (xB) and xSPECT Quant (xQ). Mean standardized uptake values (SUVmean) in volumes of interest (VOI) were calculated. Recovery coefficients (RCs) for each tumor site were calculated with reference to radioactive concentrations. The SUVmeans of the whole vertebral body for hot tumor bone image in cortical bone phantom reconstructed by with xB and xQ were 5.77 and 4.86 respectively. The SUVmean of xB was similar to the true value. The SUVmeans for xB and xQ reconstructed images of cold tumors were both approximately 0.16. The RC of the cold tumor on xQ images increased as the tumor diameter decreased, whereas that of xB remained almost constant regardless of the tumor diameter. In conclusion, the quantitative accuracy of detecting hot and cold tumors was higher in the xB image than in the xQ image. Moreover, the visual detectability of cold tumors was also excellent in xB images.

Effect of denosumab in treatment of unresectable spine and sacrum giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a rare tumor of the bone that is locally invasive. Surgery is the primary treatment that is usually done by intralesional curettage. In pelvis and spine surgery may be associated with high rate of complications, recently, Denosumab has been proposed for the treatment of these tumors in latter anatomical regions. Denosumab may be administered alone or as an adjuvant to surgery. This study aimed to assess the treatment effects of Denosumab in patients with unresectable GCTB. This study was a case series. Patients with unresectable GCTB of vertebra and sacrum were enrolled in this study. Patients received 120 mg of monthly Denosumab and additional doses on days 8th and 15th of treatment. Images of patients before and after treatment were evaluated. Nine patients with a median age of 30 years with spine and sacrum GCTB were included in this study. The median time of treatment with denosumab was 28 months (range: 3-67). Tumor control was seen in all patients. According to Inverse Choi density/size (ICDS), criteria objective response (complete response and partial response) was seen in 8 patients, and one had stable disease. Based on CT scan images, in 4 patients (44.44%), less than 50% of the transverse diameter of the tumor became ossified, and in the other five patients (55.55%), more than 50% of the tumor's transverse diameter became ossified. The median tumor volume before treatment was 829 cm3, and after treatment was 504 cm3 which was significantly reduced (P = 0.005). No complication related to therapy was seen. Tumor response was seen in all patients, and tumor control according to ICDS criteria was evident in all cases. This finding was in line with previous studies. Clinical improvement of signs and symptoms was also seen in all patients. Generally, our study demonstrates a sustained clinical benefit and tumor response with Denosumab, as tumor response ≥ 24 weeks was evident in all cases. No side effects were seen in patients despite long-term treatment with Denosumab.

Advancements in the development of radiopharmaceuticals for nuclear medicine applications in the treatment of bone metastases

Bone metastases are a painful and complex condition that overwhelmingly impacts the prognosis and quality of life of cancer patients. Over the years, nuclear medicine has made remarkable progress in the diagnosis and management of bone metastases. This review aims to provide a comprehensive overview of the recent advancements in nuclear medicine for the diagnosis and management of bone metastases. Furthermore, the review explores the role of targeted radiopharmaceuticals in nuclear medicine for bone metastases, focusing on radiolabeled molecules that are designed to selectively target biomarkers associated with bone metastases, including osteocytes, osteoblasts, and metastatic cells. The applications of radionuclide-based therapies, such as strontium-89 (Sr-89) and radium-223 (Ra-223), are also discussed. This review also highlights the potential of theranostic approaches for bone metastases, enabling personalized treatment strategies based on individual patient characteristics. Importantly, the clinical applications and outcomes of nuclear medicine in osseous metastatic disease are discussed. This includes the assessment of treatment response, predictive and prognostic value of imaging biomarkers, and the impact of nuclear medicine on patient management and outcomes. The review identifies current challenges and future perspectives on the role of nuclear medicine in treating bone metastases. It addresses limitations in imaging resolution, radiotracer availability, radiation safety, and the need for standardized protocols. The review concludes by emphasizing the need for further research and advancements in imaging technology, radiopharmaceutical development, and integration of nuclear medicine with other treatment modalities. In summary, advancements in nuclear medicine have significantly improved the diagnosis and management of osseous metastatic disease and future developements in the integration of innovative imaging modalities, targeted radiopharmaceuticals, radionuclide production, theranostic approaches, and advanced image analysis techniques hold great promise in improving patient outcomes and enhancing personalized care for individuals with bone metastases.

Ct-based intratumoral and peritumoral radiomics for predicting prognosis in osteosarcoma: A multicenter study

PURPOSE

To evaluate the performance of CT-based intratumoral, peritumoral and combined radiomics signatures in predicting prognosis in patients with osteosarcoma.

METHODS

The data of 202 patients (training cohort:102, testing cohort:100) with osteosarcoma admitted to the two hospitals from August 2008 to February 2022 were retrospectively analyzed. Progression free survival (PFS) and overall survival (OS) were used as the end points. The radiomics features were extracted from CT images, three radiomics signatures（RSintratumoral, RSperitumoral, RScombined）were constructed based on intratumoral, peritumoral and combined radiomics features, respectively, and the radiomics score (Rad-score) were calculated. Kaplan-Meier survival analysis was used to evaluate the relationship between the Rad-score with PFS and OS, the Harrell's concordance index (C-index) was used to evaluate the predictive performance of the radiomics signatures.

RESULTS

Finally, 8, 6, and 21 features were selected for the establishment of RSintratumoral, RSperitumoral, and RScombined, respectively. Kaplan-Meier survival analysis confirmed that the Rad-scores of the three RSs were significantly correlated with the PFS and OS of patients with osteosarcoma. Among the three radiomics signatures, RScombined had better predictive performance, the C-index of PSF prediction was 0.833 in the training cohort and 0.814 in the testing cohort, the C-index of OS prediction was 0.796 in the training cohort and 0.764 in the testing cohort.

CONCLUSIONS

CT-based intratumoral, peritumoral and combined radiomics signatures can predict the prognosis of patients with osteosarcoma, which may assist in individualized treatment and improving the prognosis of osteosarcoma patients.

X-rays radiomics-based machine learning classification of atypical cartilaginous tumour and high-grade chondrosarcoma of long bones

BACKGROUND

Atypical cartilaginous tumour (ACT) and high-grade chondrosarcoma (CS) of long bones are respectively managed with active surveillance or curettage and wide resection. Our aim was to determine diagnostic performance of X-rays radiomics-based machine learning for classification of ACT and high-grade CS of long bones.

METHODS

This retrospective, IRB-approved study included 150 patients with surgically treated and histology-proven lesions at two tertiary bone sarcoma centres. At centre 1, the dataset was split into training (n = 71 ACT, n = 24 high-grade CS) and internal test (n = 19 ACT, n = 6 high-grade CS) cohorts, respectively, based on the date of surgery. At centre 2, the dataset constituted the external test cohort (n = 12 ACT, n = 18 high-grade CS). Manual segmentation was performed on frontal view X-rays, using MRI or CT for preliminary identification of lesion margins. After image pre-processing, radiomic features were extracted. Dimensionality reduction included stability, coefficient of variation, and mutual information analyses. In the training cohort, after class balancing, a machine learning classifier (Support Vector Machine) was automatically tuned using nested 10-fold cross-validation. Then, it was tested on both the test cohorts and compared to two musculoskeletal radiologists' performance using McNemar's test.

FINDINGS

Five radiomic features (3 morphology, 2 texture) passed dimensionality reduction. After tuning on the training cohort (AUC = 0.75), the classifier had 80%, 83%, 79% and 80%, 89%, 67% accuracy, sensitivity, and specificity in the internal (temporally independent) and external (geographically independent) test cohorts, respectively, with no difference compared to the radiologists (p ≥ 0.617).

INTERPRETATION

X-rays radiomics-based machine learning accurately differentiates between ACT and high-grade CS of long bones.

FUNDING

AIRC Investigator Grant.

Malignant giant cell tumour of distal ulna

Giant cell tumour (GCT) accounts for 5% of all primary bone tumours. GCT in the distal third of ulna is quite rare. We present a case of recurrent GCT in distal third of ulna with malignant features involving tenosynovium. The case was treated by wide resection of tumour and on follow up, patient recovered well with no evidence of further recurrence. Considering the features, according to the literature reviewed, is the first case of its type.

Intraosseous hemangioma with aneurysmal bone cyst-like changes of the hyoid bone: Case report and literature review

RATIONALE

Intraosseous hemangioma is a rare benign vascular tumor of the bone that can affect any body part; however, the most common site is the vertebra, followed by calvarial bones.

PATIENT CONCERNS

We present a case of intraosseous hemangioma in a 23-year-old male who presented a feeling of fullness in the throat for 3 months. The hyoid bone level had a hard mass of about 5 cm. Fine needle aspiration showed 5 mL dark bloody aspirates. Magnetic resonance image showed a 5.3 cm mixed signal intensity lesion in the hyoid body.

DIAGNOSIS

Histopathologic examination showed intraosseous hemangioma with aneurysmal bone cyst (ABC)-like changes in the hyoid bone.

INTERVENTIONS

The mass was completely removed without significant problems.

OUTCOMES

Complete mass excision and symptomatic improvements were achieved, and no subsequent relapses were observed.

LESSONS

The authors experienced a case of intraosseous hemangioma with ABC-like changes. There has been no case report of intraosseous hemangioma in the hyoid bone. This case showed a spectral pattern of the ABC-like changes developing from the underlying bone tumor as a secondary change. ABC-like changes in bone tumors can mislead the diagnosis. Careful examination of the tumor is essential for the correct diagnosis of ABC or ABC-like changes.

Deep learning algorithm-based multimodal MRI radiomics and pathomics data improve prediction of bone metastases in primary prostate cancer

PURPOSE

Bone metastasis is a significant contributor to morbidity and mortality in advanced prostate cancer, and early diagnosis is challenging due to its insidious onset. The use of machine learning to obtain prognostic information from pathological images has been highlighted. However, there is a limited understanding of the potential of early prediction of bone metastasis through the feature combination method from various sources. This study presents a method of integrating multimodal data to enhance the feasibility of early diagnosis of bone metastasis in prostate cancer.

METHODS AND MATERIALS

Overall, 211 patients diagnosed with prostate cancer (PCa) at Gansu Provincial Hospital between January 2017 and February 2023 were included in this study. The patients were randomized (8:2) into a training group (n = 169) and a validation group (n = 42). The region of interest (ROI) were segmented from the three magnetic resonance imaging (MRI) sequences (T2WI, DWI, and ADC), and pathological features were extracted from tissue sections (hematoxylin and eosin [H&E] staining, 10 × 20). A deep learning (DL) model using ResNet 50 was employed to extract deep transfer learning (DTL) features. The least absolute shrinkage and selection operator (LASSO) regression method was utilized for feature selection, feature construction, and reducing feature dimensions. Different machine learning classifiers were used to build predictive models. The performance of the models was evaluated using receiver operating characteristic curves. The net clinical benefit was assessed using decision curve analysis (DCA). The goodness of fit was evaluated using calibration curves. A joint model nomogram was eventually developed by combining clinically independent risk factors.

RESULTS

The best prediction models based on DTL and pathomics features showed area under the curve (AUC) values of 0.89 (95% confidence interval [CI], 0.799-0.989) and 0.85 (95% CI, 0.714-0.989), respectively. The AUC for the best prediction model based on radiomics features and combining radiomics features, DTL features, and pathomics features were 0.86 (95% CI, 0.735-0.979) and 0.93 (95% CI, 0.854-1.000), respectively. Based on DCA and calibration curves, the model demonstrated good net clinical benefit and fit.

CONCLUSION

Multimodal radiomics and pathomics serve as valuable predictors of the risk of bone metastases in patients with primary PCa.

Arthroscopic treatment of osteoid osteoma in the posterior proximal tibia: A case report and literature review

BACKGROUND

Osteoid osteoma (OO) is a benign lesion characterized by an increased fibrous component in the bone marrow, presence of bone-like structures within the medullary cavity, and a surrounding sclerotic bone rim. Reports on OO located in the posterior proximal tibia are rare.

CASE SUMMARY

Herein, we report the case of an 18-year-old male, admitted for the evaluation of right knee pain. The right knee pain had started 6 months prior without any apparent cause, which was notably severe at night, affecting sleep, and was exacerbated while climbing stairs or bearing weight. The patient also experienced pain on flexion. Three-dimensional computed tomography and magnetic resonance imaging revealed a nodular lesion beneath the cortical bone of the posterior medial plateau of the right tibia and an abnormal signal focus on the posterior lateral aspect of the right tibial plateau associated with extensive bone marrow edema. A small amount of fluid was present in the right knee joint capsule. The patient subsequently underwent arthroscopic excision of the OO. Postoperatively, there was significant relief of pain, and the knee range of motion returned to normal.

CONCLUSION

Although OO in the posterior proximal tibia is a rare occurrence, it can be effectively excised through minimally invasive arthroscopic visualization.

Can conventional magnetic resonance imaging at presentation predict chemoresistance in osteosarcoma?

OBJECTIVES

Histological tumour necrosis is the current indicator for the response of osteosarcoma after neoadjuvant chemotherapy. Chemoresistant tumours require close monitoring and adjustment of treatment. Characteristics of tumours on baseline MRI may be able to predict response to chemotherapy. The aim is to identify which baseline MRI findings can help predict chemoresistant osteosarcoma.

METHODS

Baseline MRI before giving neoadjuvant chemotherapy of 95 patients during 2008-2021 was reviewed by 2 musculoskeletal radiologists. Histological necrosis from surgical specimens was the reference standard. MRIs were reviewed for tumour characteristics (tumour volume, maximum axial diameter, central necrosis, haemorrhage, fluid-fluid level), peritumoural bone and soft tissue oedema, and other parameters including intra-articular extension, epiphyseal involvement, neurovascular involvement, pathologic fracture, and skip metastasis. The cut-off thresholds were generated by receiver operating characteristic curves which then tested for diagnostic accuracy.

RESULTS

Two-third of patients were chemoresistance (histological necrosis <90%). Tumour volume >150 mL, maximum axial diameter >7.0 cm, area of necrosis >50%, presence of intra-articular extension, and peritumoural soft tissue oedema >6.5 cm significantly predicted chemoresistance, particularly when found in combination. Tumour volume >150 mL and maximum axial diameter >7.0 cm could be used as an independent predictor (multivariable analysis, P-value = .025, .045).

CONCLUSIONS

Findings on baseline MRI could help predicting chemoresistant osteosarcoma with tumour size being the strongest predictor.

ADVANCES IN KNOWLEDGE

Osteosarcomas with large size, large cross-sectional diameter, large area of necrosis, presence of intra-articular extension, and extensive peritumoural soft tissue oedema were most likely to have a poor response to neoadjuvant chemotherapy.

Differentiation of bone metastases from benign red marrow depositions: utilizing qualitative and quantitative analysis of conventional T1-weighted imaging and fat-suppressed T2-weighted imaging

OBJECTIVES

To distinguish bone metastases (BMs) from benign red marrow depositions (BRMs) by qualitative and quantitative analyses of T1-weighted imaging and fat-suppressed T2-weighted imaging (T2 FS).

METHODS

For 75 lesions including 38 BMs and 37 BRMs, two radiologists independently evaluated magnetic resonance images by qualitative (signal intensity [SI] of lesions compared to that of normal muscle [NM] or normal bone marrow [NBM]) and quantitative (parameters of the region of interests in the lesions, including T1 ratio [T1 SI ratio of lesion and NM], T2FMu ratio [T2 FS SI ratio of lesion and NM], and T2FMa ratio [T2 FS SI ratio of lesion and NBM]) analyses.

RESULTS

Hyperintensity relative to NM or NBM on T2 FS was more frequent in BMs than in BRMs (100% vs 59.5%-78.4%, respectively; P ≤ 0.001) but also was present in more than half of BRMs. All quantitative parameters showed a significant difference between BMs and BRMs (T1 ratio, 1.075 vs 1.227 [P = 0.002]; T2FMu ratio, 2.094 vs 1.282 [P < 0.001]; T2FMa ratio, 3.232 vs 1.810 [P < 0.001]). The receiver operating characteristics areas under the curves of T2FMu and T2FMa ratios were clinically useful (0.781 and 0.841, respectively) and did not demonstrate statistically significant differences.

CONCLUSIONS

The quantitative analysis of T2 FS facilitates distinguishing between BMs and BRMs, regardless of whether the reference was NM or NBM.

ADVANCES IN KNOWLEDGE

Quantitative parameters derived from T2 FS facilitate differentiation of BMs BRMs without additional scans. The role of NBM as an internal standard for T2 FS to differentiate between BMs and BRMs is similar to that of NM.

Diagnosis and monitoring denosumab therapy of giant cell tumors of bone: radiologic-pathologic correlation

OBJECTIVE

To determine the value of CT and dynamic contrast-enhanced (DCE-)MRI for monitoring denosumab therapy of giant cell tumors of bone (GCTB) by correlating it to histopathology.

MATERIALS AND METHODS

Patients with GCTB under denosumab treatment and monitored with CT and (DCE-)MRI (2012-2021) were retrospectively included. Imaging and (semi-)quantitative measurements were used to assess response/relapse. Tissue samples were analyzed using computerized segmentation for vascularization and number of neoplastic and giant cells. Pearson's correlation/Spearman's rank coefficient and Kruskal-Wallis tests were used to assess correlations between histopathology and radiology.

RESULTS

Six patients (28 ± 8years; five men) were evaluated. On CT, good responders showed progressive re-ossification (+7.8HU/month) and cortical remodeling (woven bone). MRI showed an SI decrease relative to muscle on T1-weighted (-0.01 A.U./month) and on fat-saturated T2-weighted sequences (-0.03 A.U./month). Time-intensity-curves evolved from a type IV with high first pass, high amplitude, and steep wash-out to a slow type II. An increase in time-to-peak (+100%) and a decrease in Ktrans (-71%) were observed. This is consistent with microscopic examination, showing a decrease of giant cells (-76%), neoplastic cells (-63%), and blood vessels (-28%). There was a strong statistical significant inverse correlation between time-to-peak and microvessel density (ρ = -0.9, p = 0.01). Significantly less neoplastic (p = 0.03) and giant cells (p = 0.04) were found with a time-intensity curve type II, compared to a type IV. Two patients showed relapse after initial good response when stopping denosumab. Inverse imaging and pathological findings were observed.

CONCLUSION

CT and (DCE-)MRI show a good correlation with pathology and allow adequate evaluation of response to denosumab and detection of therapy failure.

The effect of deep learning-based lesion segmentation on failure load calculations of metastatic femurs using finite element analysis

Bone ranks as the third most frequent tissue affected by cancer metastases, following the lung and liver. Bone metastases are often painful and may result in pathological fracture, which is a major cause of morbidity and mortality in cancer patients. To quantify fracture risk, finite element (FE) analysis has shown to be a promising tool, but metastatic lesions are typically not specifically segmented and therefore their mechanical properties may not be represented adequately. Deep learning methods potentially provide the opportunity to automatically segment these lesions and change the mechanical properties more adequately. In this study, our primary focus was to gain insight into the performance of an automatic segmentation algorithm for femoral metastatic lesions using deep learning methods and the subsequent effects on FE outcomes. The aims were to determine the similarity between manual segmentation and automatic segmentation; the differences in predicted failure load between FE models with automatically segmented osteolytic and mixed lesions and the models with CT-based lesion values (the gold standard); and the effect on the BOne Strength (BOS) score (failure load adjusted for body weight) and subsequent fracture risk assessments. From two patient cohorts, a total number of 50 femurs with osteolytic and mixed metastatic lesions were included in this study. The femurs were segmented from CT images and transferred into FE meshes. The material behavior was implemented as non-linear isotropic. These FE models were considered as gold standard (Finite Element no Segmented Lesion: FE-no-SL), whereby the local calcium equivalent density of both femur and metastatic lesion was extracted from CT-values. Lesions in the femur were manually segmented by two biomechanical experts after which final lesion segmentation for each femur was obtained based on consensus of opinions between two observers. Subsequently, a self-configuring variant of the popular deep learning model U-Net known as nnU-Net was used to automatically segment metastatic lesions within the femur. For these models with segmented lesions (Finite Element with Segmented Lesion: FE-with-SL), the calcium equivalent density within the metastatic lesions was set to zero after being segmented by the neural network, simulating absence of load-bearing capacity of these lesions. The models (either with or without automatically segmented lesions) were loaded incrementally in axial direction until failure was simulated. Dice coefficient was used to evaluate the similarity of the manual and automatic segmentation. Mean calcium equivalent density values within the automatically segmented lesions were calculated. Failure loads and patterns were determined. Furthermore, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both groups by comparing the predictions to the occurrence or absence of actual fracture within the patient cohorts. The automatic segmentation algorithm performed in a none-robust manner. Dice coefficients describing the similarity between consented manual and automatic segmentations were relatively low (mean 0.45 ± standard deviation 0.33, median 0.54). Failure load difference between the FE-no-SL and FE-with-SL groups varied from 0 % to 48 % (mean 6.6 %). Correlation analysis of failure loads between the two groups showed a strong relationship (R2 > 0.9). From the 50 cases, four cases showed clear deviations for which models with automatic lesion segmentation (FE-with-SL) showed considerably lower failure loads. In the whole database including osteolytic and mixed lesions, sensitivity and NPV remained the same, but specificity and PPV decreased from 94 % to 83 %, and from 78 % to 54 % respectively from FE-no-SL to FE-with-SL. This study indicates that the nnU-Net yielded none-robust outcomes in femoral lesion segmentation and that other segmentation algorithms should be considered. However, the difference in failure pattern and failure load between FE models with automatically segmented osteolytic and mixed lesions were relatively small in most cases with a few exceptions. On the other hand, the accuracy of fracture risk assessment using the BOS score was lower compared to the FE-no-SL. In conclusion, this study showed that automatic lesion segmentation is a none-solved issue and therefore, quantifying lesion characteristics and the subsequent effect on the fracture risk using deep learning will remain challenging.

Tracked ultrasound registration for intraoperative navigation during pediatric bone tumor resections with soft tissue components: a porcine cadaver study

PURPOSE

Resection of pediatric osteosarcoma in the extremities with soft tissue involvement presents surgical challenges due to difficult visualization and palpation of the tumor. Therefore, an adequate image-guided surgery (IGS) system is required for more accurate tumor resection. The use of a 3D model in combination with intraoperative tracked ultrasound (iUS) may enhance surgical decision making. This study evaluates the clinical feasibility of iUS as a surgical tool using a porcine cadaver model.

METHODS

First, a 3D model of the porcine lower limb was created based on preoperative scans. Second, the bone surface of the tibia was automatically detected with an iUS by a sweep on the skin. The bone surface of the preoperative 3D model was then matched with the bone surface detected by the iUS. Ten artificial targets were used to calculate the target registration error (TRE). Intraoperative performance of iUS IGS was evaluated by six pediatric surgeons and two pediatric oncologic orthopedists. Finally, user experience was assessed with a post-procedural questionnaire.

RESULTS

Eight registration procedures were performed with a mean TRE of 6.78 ± 1.33 mm. The surgeons agreed about the willingness for clinical implementation in their current clinical practice. They mentioned the additional clinical value of iUS in combination with the 3D model for the localization of the soft tissue components of the tumor. The concept of the proposed IGS system is considered feasible by the clinical panel, but the large TRE and degree of automation need to be addressed in further work.

CONCLUSION

The participating pediatric surgeons and orthopedists were convinced of the clinical value of the interaction between the iUS and the 3D model. Further research is required to improve the surgical accuracy and degree of automation of iUS-based registration systems for the surgical management of pediatric osteosarcoma.

Does A Single Osteotomy Technique for Frozen Autograft (Pedicled Freezing) in Patients With Malignant Bone Tumors of the Long Bones Achieve Union and Local Tumor Control?

BACKGROUND

Biological reconstruction by replanting the resected tumor-bearing segment is preferred by some surgeons when caring for a patient with a bone sarcoma. Frozen autografts are advantageous because they are cost-effective, provide an excellent fit, permit the maintenance of osteoinductive and osteoconductive properties, and are not associated with transmission of viral disease. The pedicle frozen autograft technique, in which only one osteotomy is made for the freezing procedure, keeping the affected segment in continuity with the host bone and soft tissue instead of two osteotomies, maintains the affected segment with the host bone and soft tissue. This could restore blood flow more rapidly in a frozen autograft than in a free-frozen autograft with two osteotomies.

QUESTIONS/PURPOSES

(1) In what proportion of patients was union achieved by 6 months using this technique of frozen autografting? (2) What complications were observed in a small series using this approach? (3) What was the function of these patients as determined by Musculoskeletal Tumor Society (MSTS) score? (4) What proportion of patients experienced local recurrence?

METHODS

Between 2014 and 2017, we treated 87 patients for primary sarcomas of the femur, tibia, or humerus. Of those, we considered patients who could undergo intercalary resection and showed a good response to neoadjuvant chemotherapy as potentially eligible for this technique. Based on these criteria, 49% (43 patients) were eligible; a further 9% (eight) were excluded because of inadequate bone quality (defined as cortical thickness less than 50% by CT assessment). We retrospectively studied 32 patients who were treated with a single metaphyseal osteotomy, the so-called pedicle freezing technique, which uses liquid nitrogen. There were 20 men and 12 women. The median age was 18 years (range 13 to 48 years). The median follow-up duration was 55 months (range 48 to 63 months). Patients were assessed clinically and radiologically regarding union (defined in this study as bony bridging of three of four cortices by 6 months), the proportion of patients experiencing local recurrence, the occurrence of nononcologic complications, and MSTS scores.

RESULTS

Three percent (one of 32) of the patients had nonunion (no union by 9 months). The median MSTS score was 90%, with no evidence of metastases at the final follow-up interval. Nine percent (three of 32) of our patients died. The local recurrence rate was 3.1% (one of 32 patients). The mean restricted disease-free survival time at 60 months (5 years) was 58 months (95% CI 55 to 62 months). Twenty-five percent of patients (eight of 32) experienced nononcologic complications. This included superficial skin burns (two patients), superficial wound infection (two patients), deep venous thrombosis (one patient), transient nerve palsy (two patients), and permanent nerve palsy (one patient).

CONCLUSION

This treatment was reasonably successful in patients with sarcomas of the femur, tibia, and humerus who could undergo an intercalary resection, and this treatment did not involve the epiphysis and upper metaphysis. It avoids a second osteotomy site as in prior reports of freezing techniques, and union was achieved in all but one patient. There were few complications or local recurrences, and the patients' function was shown to be good. This technique cannot be used in all long-bone sarcomas, but we believe this is a reasonable alternative treatment for patients who show a good response to neoadjuvant chemotherapy, those in whom intercalary resection is feasible while retaining at least 2 cm of the subchondral area, and in those who have adequate bone stock to withstand the freezing process. Experienced surgeons who are well trained on the recycling technique in specialized centers are crucial to perform the technique. Further study is necessary to see how this technique compares with other reconstruction options.

LEVEL OF EVIDENCE

Level IV, therapeutic study.