The Role of Nuclear Medicine Imaging with 18F-FDG PET/CT, Combined 111In-WBC/99mTc-Nanocoll, and 99mTc-HDP SPECT/CT in the Evaluation of Patients with Chronic Problems after TKA or THA in a Prospective Study

Imaging in Periprosthetic Joint Infection Diagnosis: A Comprehensive Review

Various imaging methods assist in diagnosing periprosthetic joint infection (PJI). These include radiological techniques such as radiography, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US); as well as advanced nuclear medicine techniques including bone scintigraphy (BS), anti-granulocyte antibody imaging (AGS), leukocyte scintigraphy (LS), and fluorodeoxyglucose positron emission tomography (FDG-PET and FDG-PET/CT). Each imaging technique and radiopharmaceutical has been extensively studied, with unique diagnostic accuracy, limitations, and benefits for PJI diagnosis. This review aims to detail and describe the most commonly used imaging techniques and radiopharmaceuticals for evaluating PJI, focusing particularly on knee and hip arthroplasties.

Diagnostic performance of SPECT/CT for identification of aseptic loosening after total knee and hip arthroplasty: a systematic review and meta-analysis

Despite an increasing number of studies examining the effect of Single-Photon Emission Computed Tomography/ Computed Tomography (SPECT/CT) on improvement of diagnosis of aseptic loosening, there is still a great deal of uncertainty regarding its applicability in diagnostic algorithm. Therefore, in this meta-analysis, we aimed to investigate the diagnostic performance of SPECT/CT for identification of aseptic loosening in patients with persistent pain following the total knee arthroplasty (TKA) and total hip arthroplasty (THA). Electronic databases including Medline, Scopus, Web of Science, Cochrane library, and Embase were systematically searched for identifying relevant published studies from their inception to April 2023. Quality evaluation of the included studies was carried out using Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). SPECT/CT had pooled sensitivity of 94% (95% CI: 92-95%) and pooled specificity of 86% (95% CI: 83-89%) for diagnosis of aseptic loosening. The pooled positive likelihood ratio (LR) was estimated as 6.92 (95% CI: 3.74-12.81), the pooled negative LR was estimated as 0.1 (95% CI: 0.06-0.16), and the pooled diagnostic odds ratio (DOR) was estimated as 89.82 (95% CI: 33.04- 244.21). The Summary receiver operating characteristics (SROC) analysis revealed high accuracy with an area under curve (AUC) of 0.96. The findings of this meta-analysis revealed that SPECT/CT has high sensitivity and specificity for diagnosis of aseptic loosening in patients who underwent TKA or THA. Therefore, SPECT/CT can be considered as an encouraging diagnostic adjunct, particularly in cases with uncertain results of bone scan.

Periprosthetic hip infection: Current concepts and the Wrightington experience

Total hip arthroplasty (THA) is a highly successful operation performed worldwide in increasing numbers for a wide range of indications. There has been a corresponding rise in the incidence of periprosthetic joint infection of the hip (PJIH), which is a devastating complication. There is a significant variation in the definition, diagnosis and management of PJIH largely due to a lack of high-level evidence. The current standard of practice is largely based on cohort studies from high-volume centres, consensus publications amongst subject experts, and national guidance. This review describes our philosophy and practical approach of managing PJIH at a regional tertiary high-volume joint replacement centre.

Protein-Based Nanocarriers and Nanotherapeutics for Infection and Inflammation

Infectious and inflammatory diseases are one of the leading causes of death globally. The status quo has become more prominent with the onset of the coronavirus disease 2019 (COVID-19) pandemic. To combat these potential crises, proteins have been proven as highly efficacious drugs, drug targets, and biomarkers. On the other hand, advancements in nanotechnology have aided efficient and sustained drug delivery due to their nano-dimension-acquired advantages. Combining both strategies together, the protein nanoplatforms are equipped with the advantageous intrinsic properties of proteins as well as nanoformulations, eloquently changing the field of nanomedicine. Proteins can act as carriers, therapeutics, diagnostics, and theranostics in their nanoform as fusion proteins or as composites with other organic/inorganic materials. Protein-based nanoplatforms have been extensively explored to target the major infectious and inflammatory diseases of clinical concern. The current review comprehensively deliberated proteins as nanocarriers for drugs and nanotherapeutics for inflammatory and infectious agents, with special emphasis on cancer and viral diseases. A plethora of proteins from diverse organisms have aided in the synthesis of protein-based nanoformulations. The current study specifically presented the proteins of human and pathogenic origin to dwell upon the field of protein nanotechnology, emphasizing their pharmacological advantages. Further, the successful clinical translation and current bottlenecks of the protein-based nanoformulations associated with the infection-inflammation paradigm have also been discussed comprehensively. SIGNIFICANCE STATEMENT: This review discusses the plethora of promising protein-based nanocarriers and nanotherapeutics explored for infectious and inflammatory ailments, with particular emphasis on protein nanoparticles of human and pathogenic origin with reference to the advantages, ADME (absorption, distribution, metabolism, and excretion parameters), and current bottlenecks in development of protein-based nanotherapeutic interventions.

An artificial intelligence framework for the diagnosis of prosthetic joint infection based on 99mTc-MDP dynamic bone scintigraphy

OBJECTIVES

Dynamic bone scintigraphy (DBS) is the first widely reliable and simple imaging modality in nuclear medicine that can be used to diagnose prosthetic joint infection (PJI). We aimed to apply artificial intelligence to diagnose PJI in patients after total hip or knee arthroplasty (THA or TKA) based on 99mTc-methylene diphosphonate (99mTc-MDP) DBS.

METHODS

A total of 449 patients (255 THAs and 194 TKAs) with a final diagnosis were retrospectively enrolled and analyzed. The dataset was divided into a training and validation set and an independent test set. A customized framework composed of two data preprocessing algorithms and a diagnosis model (dynamic bone scintigraphy effective neural network, DBS-eNet) was compared with mainstream modified classification models and experienced nuclear medicine specialists on corresponding datasets.

RESULTS

In the fivefold cross-validation test, diagnostic accuracies of 86.48% for prosthetic knee infection (PKI) and 86.33% for prosthetic hip infection (PHI) were obtained using the proposed framework. On the independent test set, the diagnostic accuracies and AUC values were 87.74% and 0.957 for PKI and 86.36% and 0.906 for PHI, respectively. The customized framework demonstrated better overall diagnostic performance compared to other classification models and showed superiority in diagnosing PKI and consistency in diagnosing PHI compared to specialists.

CONCLUSION

The customized framework can be used to effectively and accurately diagnose PJI based on 99mTc-MDP DBS. The excellent diagnostic performance of this method indicates its potential clinical practical value in the future.

KEY POINTS

• The proposed framework in the current study achieved high diagnostic performance for prosthetic knee infection (PKI) and prosthetic hip infection (PHI) with AUC values of 0.957 and 0.906, respectively. • The customized framework demonstrated better overall diagnostic performance compared to other classification models. • Compared to experienced nuclear medicine physicians, the customized framework showed superiority in diagnosing PKI and consistency in diagnosing PHI.

Diagnostic accuracy of positron emission tomography/computerized tomography for periprosthetic joint infection of hip: systematic review and meta-analysis

BACKGROUND

American Academy of Orthopaedic Surgeons (AAOS) has provided the guidelines for diagnosing a patient with periprosthetic joint infection including the use of positron emission tomography/computed tomography (PET/CT). Systematic evidence focussing on periprosthetic joint infection (PJI) of hip is limited, which also contains limited number of studies. Hence, the current study aims to perform a pooled analysis of all studies that have assessed the diagnostic accuracy of PET/CT for PJI of hip.

METHODS

Searches were done in PubMed Central, EMBASE, MEDLINE, SCOPUS and Cochrane library until December 2022. Meta-analysis was carried out using random-effects model. With 95% confidence intervals (CIs), pooled sensitivity and specificity were reported.

RESULTS

Twenty-six studies met the inclusion criteria. The pooled sensitivity of PET/CT was 89% (95% CI 84-93%), while the pooled specificity was 86% (95% CI 79-91%). The AUROC was 0.94 (95% CI 0.72-0.99). There was statistically significant heterogeneity (p < 0.001) with I2 value of 96%. The diagnostic odds ratio was 52 (95% CI 26-106). Likelihood ratio positive was 6.5 (95% CI 4.1-10.3) and negative was 0.13 (95% CI 0.08-0.19).

CONCLUSION

Our study found that PET/CT was found to have higher level of accuracy in terms of sensitivity and specificity. Further large-scale research can help to find answers for such questions and provide final conclusive evidence on the inclusion of the imaging modality into the routine clinical practice guidelines for suspected periprosthetic joint infection patients.

Simultaneous 18F-FDG-PET/MRI for the detection of periprosthetic joint infections after knee or hip arthroplasty: a prospective feasibility study

Purpose

This study investigated the diagnostic value of simultaneous 18F-fluordeoxyglucose positron emission tomography/magnetic resonance imaging (PET/MRI) in suspected periprosthetic joint infection (PJI) of the hip and knee.

Methods

Sixteen prostheses from 13 patients with suspected PJI were prospectively examined using PET/MRI. Image datasets were evaluated in consensus by a radiologist and a nuclear physician for the overall diagnosis of ‘PJI’ (yes/no) and its anatomical involvement, such as the periprosthetic bone margin, bone marrow, and soft tissue. The imaging results were compared with the reference standard obtained from surgical or biopsy specimens and subjected to statistical analysis.

Results

Using the reference standard, ten out of the 13 prostheses (ten hips, threes knees) were diagnosed with PJI. Using PET/MRI, every patient with PJI was correctly diagnosed (sensitivity, 100%; specificity, 100%). Considering the anatomical regions, the sensitivity and specificity were 57% and 50% in the periprosthetic bone margin, 75% and 33% in the bone marrow, and 100% and 100% in the soft tissue.

Conclusion

PET/MRI can be reliably used for the diagnosis of PJI. However, assessment of the periprosthetic bone remains difficult due to the presence of artefacts. Thus, currently, this modality is unlikely to be recommended in clinical practice.