Diabetic Foot Infections: The Diagnostic Challenges

Diagnostic imaging of the diabetic foot: an EANM evidence-based guidance

PURPOSE

Consensus on the choice of the most accurate imaging strategy in diabetic foot infective and non-infective complications is still lacking. This document provides evidence-based recommendations, aiming at defining which imaging modality should be preferred in different clinical settings.

METHODS

This working group includes 8 nuclear medicine physicians appointed by the European Association of Nuclear Medicine (EANM), 3 radiologists and 3 clinicians (one diabetologist, one podiatrist and one infectious diseases specialist) selected for their expertise in diabetic foot. The latter members formulated some clinical questions that are not completely covered by current guidelines. These questions were converted into statements and addressed through a systematic analysis of available literature by using the PICO (Population/Problem-Intervention/Indicator-Comparator-Outcome) strategy. Each consensus statement was scored for level of evidence and for recommendation grade, according to the Oxford Centre for Evidence-Based Medicine (OCEBM) criteria.

RESULTS

Nine clinical questions were formulated by clinicians and used to provide 7 evidence-based recommendations: (1) A patient with a positive probe-to-bone test, positive plain X-rays and elevated ESR should be treated for presumptive osteomyelitis (OM). (2) Advanced imaging with MRI and WBC scintigraphy, or [18F]FDG PET/CT, should be considered when it is needed to better evaluate the location, extent or severity of the infection, in order to plan more tailored treatment. (3) In a patient with suspected OM, positive PTB test but negative plain X-rays, advanced imaging with MRI or WBC scintigraphy + SPECT/CT, or with [18F]FDG PET/CT, is needed to accurately assess the extent of the infection. (4) There are no evidence-based data to definitively prefer one imaging modality over the others for detecting OM or STI in fore- mid- and hind-foot. MRI is generally the first advanced imaging modality to be performed. In case of equivocal results, radiolabelled WBC imaging or [18F]FDG PET/CT should be used to detect OM or STI. (5) MRI is the method of choice for diagnosing or excluding Charcot neuro-osteoarthropathy; [18F]FDG PET/CT can be used as an alternative. (6) If assessing whether a patient with a Charcot foot has a superimposed infection, however, WBC scintigraphy may be more accurate than [18F]FDG PET/CT in differentiating OM from Charcot arthropathy. (7) Whenever possible, microbiological or histological assessment should be performed to confirm the diagnosis. (8) Consider appealing to an additional imaging modality in a patient with persisting clinical suspicion of infection, but negative imaging.

CONCLUSION

These practical recommendations highlight, and should assist clinicians in understanding, the role of imaging in the diagnostic workup of diabetic foot complications.

[18F]Fluorodeoxyglucose ([18F]FDG) positron emission tomography and conventional imaging modalities in the diagnosis of diabetic foot osteomyelitis: a meta-analysis

AIM

This meta-analysis aimed to evaluate the comparative diagnostic efficacy of [18F]Fluorodeoxyglucose positron emission tomography ([18F]FDG PET) and conventional imaging, MRI, and white blood cell (WBC) scintigraphy in detecting foot osteomyelitis among diabetic patients.

MATERIALS AND METHODS

An exhaustive search was conducted within the PubMed and Embase databases to identify publications available up until February 2024. Studies were included if they evaluated the diagnostic efficacy of [18F]FDG PET or the comparative diagnostic performance between PET and (MRI or WBC scintigraphy). Two researchers independently assessed the quality of the included studies, utilizing the Quality Assessment of Diagnostic Performance Studies (QUADAS-2) tool.

RESULTS

Nine retrospective or prospective studies involving 605 patients were included in the meta-analysis. For [18F]FDG PET, the overall sensitivity was 0.83(95% CI: 0.69-0.94), while the overall specificity was 0.92(95% CI: 0.86-0.97). In the head-to-head comparison, no significant difference of sensitivity was found between [18F]FDG PET and MRI (0.72 vs. 0.68, P=0.81), as well as between [18F]FDG PET and WBC scintigraphy (0.57 vs. 0.66, P=0.64). In addition, specificity was also found to be no significant difference between [18F]FDG PET and MRI (0.90 vs. 0.82, P=0.27), as well as [18F]FDG PET and WBC scintigraphy (0.81 vs. 0.93, P=0.09).

CONCLUSION

[18F]FDG PET demonstrates similar sensitivity and specificity to MRI and WBC scintigraphy in detecting foot osteomyelitis among diabetic patients. MRI, often cited as a primary choice in guidelines, might be preferred due to its lower cost and lower dose. Further larger sample prospective studies are needed to confirm these findings.

Clinical practice recommendations for infectious disease management of diabetic foot infection (DFI) - 2023 SPILF

In march 2020, the International Working Group on the Diabetic Foot (IWGDF) published an update of the 2015 guidelines on the diagnosis and management of diabetic foot infection (DFI). While we (the French ID society, SPILF) endorsed some of these recommendations, we wanted to update our own 2006 guidelines and specifically provide informative elements on modalities of microbiological diagnosis and antibiotic treatment (especially first- and second-line regiments, oral switch and duration). The recommendations put forward in the present guidelines are addressed to healthcare professionals managing patients with DFI and more specifically focused on infectious disease management of this type of infection, which clearly needs a multidisciplinary approach. Staging of the severity of the infection is mandatory using the classification drawn up by the IWGDF. Microbiological samples should be taken only in the event of clinical signs suggesting infection in accordance with a strict preliminarily established protocol. Empirical antibiotic therapy should be chosen according to the IWGDF grade of infection and duration of the wound, but must always cover methicillin-sensitive Staphylococcus aureus. Early reevaluation of the patient is a fundamental step, and duration of antibiotic therapy can be shortened in many situations. When osteomyelitis is suspected, standard foot radiograph is the first-line imagery examination and a bone biopsy should be performed for microbiological documentation. Histological analysis of the bone sample is no longer recommended. High dosages of antibiotics are recommended in cases of confirmed osteomyelitis.

What Role Does PET/MRI Play in Musculoskeletal Disorders?

Musculoskeletal disorders of nononcological origin are one of the most frequent reasons for consultation. Patients suffering from musculoskeletal disorders also consult more than once for the same reason. This results in multiple clinical follow-ups after several radiological and serum examinations, the main ones including X-rays targeting the painful anatomical region and inflammatory serum parameters. As part of their work up, patients suffering from musculoskeletal disorders often require multisequence, multi-parameter MRI. PET/MRI is a promising imaging modality for their diagnosis, with the added advantage of being able to be performed in a single visit. PET/MRI is particularly useful for diagnosing osteomyelitis, spondylodiscitis, arthritis, many pediatric pathologies, and a wide range of other musculoskeletal pathologies. PET/MRI is already used to diagnose malignant bone tumors such as osteosarcoma. However, current knowledge of the indications for PET/MRI in nononcological musculoskeletal disorders is based on studies involving only a few patients. This review focuses on the usefulness of PET/MRI for diagnosing nononcological musculoskeletal disorders.

Non-Enhancing Tissue on Diabetic Foot Magnetic Resonance Imaging in Relation to Osteomyelitis Investigation: Magnetic Resonance Imaging Performance, Pitfalls and Clinical Considerations

Background: Geographic non-enhancing zones in diabetic foot magnetic resonance imaging (MRI) were first described in 2002. No previous report has described the impact and clinical significance of geographic non-enhancing tissue seen in the evaluation of diabetic foot MRI. Purpose: To evaluate the prevalence of devascularization areas on contrast-enhanced MRI in diabetic patients suspected of having foot osteomyelitis, the impact on the performance of the MRI assessment, and the possible pitfalls. Methods: A retrospective study was conducted between January 2016 and December 2017 during which 72 CE-MRIs of 1.5 and 3T were reviewed by 2 musculoskeletal radiologists for the presence of non-enhancing tissue areas and for osteomyelitis. A blinded third party collected clinical data including pathology reports, revascularization procedures, and surgical interventions. The prevalence of devascularization was calculated. Results: Among the 72 CE-MRIs (54 men, 18 women; mean age 64), 28 demonstrated non-enhancing areas (39%). All but 6 patients were found to have been correctly diagnosed on imaging (3 false positives, 2 false negatives, and 1 non-diagnostic). A greater discordance was also observed between the radiological and pathological diagnoses in the MRIs which showed non-enhancing tissue. Conclusion: Non-enhancing tissue is found in a non-negligible portion of diabetic foot MRIs and affects its diagnostic performance when looking for osteomyelitis. The recognition of these areas of devascularization may be helpful for the physician in planning the best treatment option for the patient.

State-of-the-art update for diagnosing diabetic foot osteomyelitis: a narrative review

Recently, the International Working Group on the Diabetic Foot and the Infectious Diseases Society of America divided diabetic foot disease into diabetic foot infection (DFI) and diabetic foot osteomyelitis (DFO). DFI is usually diagnosed clinically, while numerous methods exist to diagnose DFO. In this narrative review, the authors aim to summarize the updated data on the diagnosis of DFO. An extensive literature search using "diabetic foot [MeSH]" and "osteomyelitis [MeSH]" or "diagnosis" was performed using PubMed and Google Scholar in July 2023. The possibility of DFO is based on inflammatory clinical signs, including the probe-to-bone (PTB) test. Elevated inflammatory biochemical markers, especially erythrocyte sedimentation rate, are beneficial. Distinguishing abnormal findings of plain radiographs is also a first-line approach. Moreover, sophisticated modalities, including magnetic resonance imaging and nuclear medicine imaging, are helpful if doubt remains after a first-line diagnosis. Transcutaneous bone biopsy, which does not pass through the wound, is necessary to avoid contaminating the sample. This review focuses on the current diagnostic techniques for DFOs with an emphasis on the updates. To obtain the correct therapeutic results, selecting a proper option is necessary. Based on these numerous diagnosis modalities and indications, the proper choice of diagnostic tool can have favorable treatment outcomes.

Preliminary evaluation of dual-energy CT to quantitatively assess bone marrow edema in patients with diabetic foot ulcers and suspected osteomyelitis

OBJECTIVES

The purpose of this study is to evaluate the value of dual-energy CT (DECT) with virtual non-calcium (VNCa) in quantitatively assessing the presence of bone marrow edema (BME) in patients with diabetic foot ulcers and suspected osteomyelitis.

METHODS

Patients with a diabetic foot ulcer and suspected osteomyelitis that underwent DECT (80 kVp/Sn150 kVp) with VNCa were retrospectively included. Two observers independently measured CT values of the bone adjacent to the ulcer and a reference bone not related to the ulcer. The patients were divided into two clinical groups, osteomyelitis or no-osteomyelitis, based on the final diagnosis by the treating physicians.

RESULTS

A total of 56 foot ulcers were identified of which 23 were included in the osteomyelitis group. The mean CT value at the ulcer location was significantly higher in the osteomyelitis group (- 17.23 ± 34.96 HU) compared to the no-osteomyelitis group (- 69.34 ± 49.40 HU; p < 0.001). Within the osteomyelitis group, the difference between affected bone and reference bone was statistically significant (p < 0.001), which was not the case in the group without osteomyelitis (p = 0.052). The observer agreement was good for affected bone measurements (ICC = 0.858) and moderate for reference bone measurements (ICC = 0.675). With a cut-off value of - 40.1 HU, sensitivity was 87.0%, specificity was 72.7%, PPV was 69.0%, and NPV was 88.9%.

CONCLUSION

DECT with VNCa has a potential value for quantitatively assessing the presence of BME in patients with diabetic foot ulcers and suspected osteomyelitis.

KEY POINTS

• Dual-energy CT (DECT) with virtual non-calcium (VNCa) is promising for detecting bone marrow edema in the case of diabetic foot ulcers with suspected osteomyelitis. • DECT with VNCa has the potential to become a more practical alternative to MRI in assessing the presence of bone marrow edema in suspected osteomyelitis when radiographs are not sufficient to form a diagnosis.

Imaging of the Diabetic Foot

Diabetic foot complications are increasingly prevalent in the world, leading to significant morbidity and driving up associated health care costs. Complex pathophysiology and suboptimal specificity of current imaging modalities have made diagnosis challenging, mainly in the evaluation of superimposed foot infection to underlying arthropathy or other marrow lesions. Recent advances in radiology and nuclear medicine have the potential to streamline the assessment of diabetic foot complications. But we must be aware of the specific strengths and weaknesses of each modality, and their applications. This review offers a comprehensive approach to the spectrum of diabetic foot complications and their imaging appearances in conventional and advanced imaging studies, including optimal technical considerations for each technique. Advanced magnetic resonance imaging (MRI) techniques are highlighted, illustrating their complementary role to conventional MRI, in particular their potential impact in avoiding additional studies.

Role of M1 macrophages in diabetic foot ulcers and related immune regulatory mechanisms

Objectives: Diabetes foot ulcers (DFUs) are characterized by immune infiltration of M1 macrophages observed in foot skin, in which immune-associated genes (IRGs) play a prominent role. The precise expression of IRGs as well as any possible regulatory mechanisms that could be present in DFUs is yet unknown. Methods: The sequencing data of single-cell RNA (scRNA) in the foot skin of patients with DFUs were analyzed, screening out the cluster marker genes of foot skin obtained from the ImmPort database. IRG activity was assessed with the AUCell software package. The IRGs of DFUs were explored by analyzing the batch sequencing dataset of DFU skin tissue. HumanTFDB was adopted to identify relevant regulatory transcription factors (TFs). The STRING dataset was used to build the main TF protein-protein interaction networks. WB and immunofluorescence methods were used to verify M1 macrophage-related immune regulators. Results: There were 16 clusters found: SMC1, fibro, t-lympho, he fibro, vasendo, baselkera, diffkera, SMC2, M1 macro, M2 macro, sweet/seba, B-Lympho, Melanio, lymphendo, plasma, and Schwann. M1 and M2 macrophages both had considerably higher AUC ratings than patients with DFUs compared to other sub-populations of cells. The proportion of M1 macrophages was the highest in the non-healing group. According to scRNA analysis and batch sequencing data by GO and KEGG, DEGs were enriched in immune response. Some 106 M1 macro-IRGs were finally identified and 25 transcription factors were revealed as associated with IRG expression. The PPI network indicated NFE2L2, REL, ETV6, MAF, and NF1B as central transcription factors. Conclusion: Based on the bio-informatics analysis of scRNA and high-throughput sequencing data, we concluded that M1 macrophages may serve as the influencing factor of DFUs' non-union. In addition, NFE2L2 could be involved in the regulation of IRG expression within M1 macrophages.

Pathogen-specific molecular imaging and molecular testing methods in the prognosis of the complicated course of diabetic foot syndrome, the risk of amputation, and patient survival

The aim of this review was to provide extended information on current trends in the diagnosis of complicated diabetic foot syndrome (DFS), the most frequent and severe complication of diabetes mellitus, including hightech medical imaging methods and instrumental and laboratory predictors of the complicated course and risk of amputation in DFS.

The article provides an analytical review of modern publications over the past 5 years on diagnosis and therapy. Pilot data on the use of high-tech medical imaging methods, assessment of skin microbiota and ulcers in DFS, molecular testing methods in terms of predicting the amputation risk and survival of patients with DFS, as well as the effectiveness of biosensing systems have been systematized, summarized, and subjected to analytical evaluation.

The review provides an expert assessment of the capabilities of pathogen-specific molecular imaging using modern positron emission tomography (PET), single-photon emission computed tomography (SPECT), and highenergy radionuclides in bacterial infection to understand its pathogenesis, minimize diagnostic problems, improve antimicrobial treatment, and address fundamental and applied aspects of DFS. Literature data on the assessment of foot perfusion in diabetic patients with varying degrees of limb ischemia by hybrid technologies (SPECT / CT and PET / CT) and new modalities of magnetic resonance imaging (MRI) are also systematized, which contributes to new understanding of the response to revascularization, surgical shunting, and stimulation of angiogenesis within ischemic tissue, as well as potentially to healing of foot ulcers.

The review is aimed at substantiating a multidisciplinary approach in DFS, selection, development, and implementation of innovative strategies for diagnostic modalities to identify diabetic foot pathologies, and choice of an adequate method for treating and monitoring the results of therapy in the context of personalized medicine.

Could X-ray Predict Long-term Complications in Patients with Diabetic Foot Osteomyelitis?

OBJECTIVE

To analyze the association between radiologic changes on plain X-rays in patients with diabetic foot osteomyelitis and the development of complications at the 1-year follow-up.

METHODS

A prospective, observational study was conducted involving 115 patients with diabetic foot osteomyelitis. X-ray features that were evaluated during 1-year follow-up visits included affected bone marrow, active periosteal reaction, sequestrum, cortical disruption, and other types of signs. Researchers analyzed the association between the presence of X-ray changes and complication development, such as bone or soft tissue infections, ulcer recurrence, reulceration, amputation, death, and other diabetic foot disease-related events.

RESULTS

During follow-up, of 115 patients included in the study, 33 patients (28.7%) showed radiologic changes, and 85 (73.9%) developed complications. The presence of radiologic changes after ulcer healing had a significant association with complication development during the 1-year follow-up in addition to those found at different follow-up visits. Patients who showed radiologic changes had higher percentages of complications during the 1-year follow-up, and patients without radiologic changes had lower percentages of complications.

CONCLUSIONS

The presence of radiologic changes is related to the development of complications in patients who suffer from diabetic foot osteomyelitis.

The Role of Serial Radiographs in Diagnosing Diabetic Foot Bone Osteomyelitis

Background and Objective

Diagnosing diabetes-related foot osteomyelitis is sometimes a challenge for clinicians since it may occur without local or systemic signs of infection. Thus, the primary purpose of this article was to evaluate the role of progressive radiographic changes in diagnosing diabetic foot osteomyelitis.

Materials and Methods

A retrospective review of databases of our Institution was performed to identify all long-standing diabetic foot patients who underwent two radiographic examinations spaced no more than five weeks apart and a subsequent magnetic resonance (MR) examination from November 2015 to November 2020. A total of 46 patients (32 men, 14 women; mean age, 57.3 years) were identified.

Results

serial radiographs showed 89% sensitivity, 38% specificity, 80% diagnostic accuracy, 87% positive predictive value (PPV), 43% negative predictive value (NPV) to diagnose osteomyelitis (P value < 0,05). Bone destruction was the most reliable radiographic sign with 89% sensitivity, 88% specificity, 89% diagnostic accuracy, 97% PPV, 64% NPV (P value < 0,05).

Conclusion

Progressive bony changes detected by serial radiographs are a useful tool to diagnose diabetic foot osteomyelitis.

Diabetic foot infections: how to investigate more efficiently? A retrospective study in a quaternary university center

Background

Diabetic foot infections are frequent and associated with substantial morbidity and substantial cost to the healthcare system. Up to 34% of diabetic patients will develop an ulcer potentially leading to osteomyelitis. Imaging plays a crucial role in the diagnostic process. Imaging modalities to investigate the diabetic foot infection are many and imaging prescription habits remain heterogeneous across physicians. We aimed to improve the appropriateness of imaging examination requested, and performed, for diabetic foot osteomyelitis and we aimed to reduce the overall imaging-related cost.

Methods

Local committee was created to develop an algorithm for suspected diabetic foot osteomyelitis. Best practices were defined by the local algorithm. The algorithm was shared with our physicians. Pre- and post-intervention analysis was conducted retrospectively. All adult diabetic patients with suspected foot osteomyelitis were included. Adherence to best practices was measured. Statistical analysis with Chi-Square and two tailed unpaired t-test was performed.

Results

Pre-intervention cohort had 223 patients (mean age: 63; 168 men). Adherence to best practice was 43%. Scintigraphy (48%) preferred over MRI (44%) and performed simultaneously in 15 patients. Post-intervention cohort had 73 patients (mean age: 66; 62 men). Adherence to best practice was 78%, improved by 35% (p < 0.001). MRI (51%) preferred over scintigraphy (23%) and performed simultaneously in three patients. Scintigraphy examinations decreased by 25% (p < 0.001). MRI examinations increased by 7% (p = 0.32). Hospital imaging related fees decreased by 22% per patient (p = 0.002).

Conclusion

Interval improvement in adequate adherence while reducing unnecessary examinations for patients and decreasing costs for the healthcare system was observed.

Amphibian-derived peptide homodimer promotes regeneration of skin wounds

Despite the increasing treatments in skin wound repair, existing therapeutic drugs cannot meet current needs. As such, skin wound repair remains a considerable clinical challenge, and thus the discovery of new pro-healing agents is crucial. Here, we identified the first naturally occurring peptide homodimer named as OA-GP11 dimer (OA-GP11d) from Odorrana andersonii (odorous frog) through the combinational methods of peptidomics and genomics. OA-GP11d was linked by the intramolecular disulfide formed by the 10^th cysteine residues from the monomer of peptide with sequence of GPLSGINAECM, which effectively promoted the repair of full-thickness and burn wounds in mice. The underlying molecular mechanisms revealed that OA-GP11d not only accelerated the migration and cell-scratch healing of mouse keratinocytes, but also activated the mitogen-activated protein kinases (MAPKs) signaling pathway (phosphorylation of p38 and ERK subgroups) in immortalized human keratinocytes (HaCaT). Besides, OA-GP11d reduced the phosphorylation of nuclear factor-κB (NF-κB) and inhibitor of NF-κB (I-κB) induced by lipopolysaccharide stimulation in mouse macrophages, and inhibited the release of associated inflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-6. OA-GP11d is the first identified naturally occurring peptide dimer with significant pro-healing potency. Our results highlight the importance of amphibians as a source of novel pro-healing agents and suggest OA-GP11d as a potential new pro-regenerative drug candidate.

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host's immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host's immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.

Influence of Dipeptidyl Peptidase-4 (DPP4) on Mesenchymal Stem-Cell (MSC) Biology: Implications for Regenerative Medicine - Review

Dipeptidyl peptidase IV (DPP4) is a ubiquitous protease that can be found in membrane-anchored or soluble form. Incretins are one of the main DPP4 substrates. These hormones regulate glucose levels, by stimulating insulin secretion and decreasing glucagon production. Because DPP4 levels are high in diabetes, DPP4 inhibitor (DPP4i) drugs derived from gliptin are widespread used as hypoglycemic agents for its treatment. However, as DPP4 recognizes other substrates such as chemokines, growth factors and neuropeptides, pleiotropic effects have been observed in patients treated with DPP4i. Several of these substrates are part of the stem-cell niche. Thus, they may affect different physiological aspects of mesenchymal stem-cells (MSC). They include viability, differentiation, mobilization and immune response. MSC are involved in tissue homeostasis and regeneration under both physiological and pathological conditions. Therefore, such cells and their secretomes have a high clinical potential in regenerative medicine. In this context, DPP4 activity may modulate different aspects of MSC regenerative capacity. Therefore, the aim of this review is to analyze the effect of different DPP4 substrates on MSC. Likewise, how the regulation of DPP4 activity by DPP4i can be applied in regenerative medicine. That includes treatment of cardiovascular and bone pathologies, cutaneous ulcers, organ transplantation and pancreatic beta-cell regeneration, among others. Thus, DPP4i has an important clinical potential as a complement to therapeutic strategies in regenerative medicine. They involve enhancing the differentiation, immunomodulation and mobilization capacity of MSC for regenerative purposes.

The Rediscovery of Honey for Skin Repair: Recent Advances in Mechanisms for Honey-Mediated Wound Healing and Scaffolded Application Techniques

Honey is a honey-bee product obtained mainly by the enzymatic processing of nectar from a variety of plants, which leads to the wide range of colours and flavours available on the market. These organoleptic and nutritional features are influenced by the chemical composition, which in turn depends on the botanical origin. Bioactive compounds account for honey beneficial activity in medical applications, which explains the extensive use of honey in ethno-pharmacology since antiquity, from cough remedies to dermatological treatments. Wound healing is one of the main therapeutic uses of honey, and various design options in pharmaceutical technology such as smart delivery systems and advanced dressings are currently being developed to potentiate honey’s valuable properties for better performance and improved final outcome. In this review, we will focus on the latest research that discloses crucial factors in determining what properties are most beneficial when considering honey as a medicinal product. We will present the most recent updates on the possible mechanisms responsible for the exceptional effects of this ageless therapeutical remedy on skin repair. Furthermore, the state-of-the-art in application techniques (incorporation into scaffolds as an alternative to direct administration) used to enhance honey-mediated wound-healing properties are explored.

An easy and practical guide for imaging infection/inflammation by [18F]FDG PET/CT

Aim

The aim of this mini-review was to summarize the role of positron emission tomography/computed tomography (PET/CT) with ¹⁸Fluorine-fluorodeoxyglucose ([¹⁸F]FDG) in inflammatory and infective processes, based on the published scientific evidence.

Methods

We analysed clinical indications, patient preparation, image acquisition protocols, image interpretation, pitfalls and how to make the report of cardio-vascular diseases, musculoskeletal diseases and other inflammatory and infective systemic diseases.Results of this analysis are shown in practical tables, easy to understand for daily routine consultation.

Conclusions

Despite [¹⁸F]FDG is currently used in several inflammatory and infective diseases, standardized interpretation criteria are still needed in most cases. It is, therefore, foreseen the execution of multicentre clinical studies that, by adopting the same acquisition and interpretation criteria, may contribute to the standardization of this imaging modality.

Update on functional imaging in the evaluation of diabetic foot infection

Diabetic foot infection is a preventable complication of diabetes mellitus. It is an essential component of diabetic foot disease, which is characterised by a triad of neuropathy, ischaemia and infection. These factors may lead to foot ulceration, sepsis and amputation resulting in increased morbidity and poor quality of life. Confirming or excluding infection can be difficult especially when routine laboratory tests and plain radiographs are inconclusive. Early diagnosis and localization of diabetic foot infection is extremely important to institute timely, appropriate therapy. Structural imaging using computed tomography and magnetic resonance imaging all have individual applications towards the diagnostic workup of this condition but have their own limitations. Scintigraphic detection is based on physiochemical changes and hence provides a functional evaluation of bone pathology. We describe the evolution of functional nuclear medicine imaging including immunoscintigraphy in diabetic foot infection and highlight current applications of physiological 18-Fluoro-deoxyglucose positron emission tomography (18-FDG-PET) and computed tomography (18-FDG-PET/CT) in such patients. 18-FDG-PET/CT is a promising modality for imaging diabetic foot infection. Future studies will allow standardisation of technological details and options of 18-FDG-PET/CT interpretation in diabetic foot infection.

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation

AIM

The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections.

METHODS

In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [¹⁸F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020.

RESULTS

Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication.

CONCLUSIONS

Currently, [¹⁸F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

Clinical, Pathological and Microbiological Evaluation of Diabetic Foot Syndrome

Background and objectives: Diabetic foot ulcer (DFU) is one of the serious complications of diabetes, being related to frequent and long-term hospitalisation, reduced quality of life of the patient, amputations, a high rate of morbidity and mortality. The bacterial aetiology is complex, sometimes involving more than one pathogen, playing a major role in the infection prognosis and development of microbial resistance. This study evaluated the current state of the aetiology, clinical and pathological characteristics of DFU in a single diabetes centre in order to provide some specific measures to prevent it. Materials and Methods: This retrospective study was conducted on patients with diabetes mellitus (252 individuals diagnosed with DFU) between January 2018–December 2019. All participants were assessed based on their clinical characteristics, including complications of diabetes and pathological and microbiological evaluations. Results: The present research revealed that diabetic foot ulcer prevalence was higher in males than in females and higher in type 2 diabetic patients than in type 1 diabetic patients. The patients with diabetic foot ulcer were older, had a higher body mass index (BMI), longer diabetic duration and had more diabetic complications, such as retinopathy, diabetic polyneuropathy and diabetic kidney disease, than patients without diabetic foot ulceration. Conclusions: Taking into account all factors involved, including the aetiology and the antibiotic susceptibility pattern of these isolates, planning the suitable treatment options of patients is possible.