Diagnosing diabetic foot osteomyelitis in patients without signs of soft tissue infection by coupling hybrid 67Ga SPECT/CT with bedside percutaneous bone puncture

Applications of SPECT and PET Imaging for the Physiological Evaluation of Lower Extremity Peripheral Artery Disease

Peripheral artery disease (PAD) is classified as the narrowing or complete occlusion of the lower extremity arteries due to atherosclerosis. The risk of developing PAD increases with increased age and risk factors such as smoking, diabetes, hypertension, and hypercholesterolemia. Current treatment for PAD involves lifestyle and symptom management, statin and antiplatelet therapy, and/or surgical interventions to improve quality of life with varying efficacy. PAD affects approximately 5 to 6 percent of the global population, with this global burden continuing to increase. Despite the increase in disease prevalence, no gold standard functional diagnostic tool has been established for enabling early detection of the disease, appropriate medical management, and prediction of adverse outcomes for PAD patients. The visualization and quantification of the physiological consequences of PAD are possible by way of nuclear imaging: specifically, via scintigraphy, single-photon emission computed tomography (SPECT), and positron emission tomography (PET) imaging. These non-invasive modalities, when combined with targeted radionuclides, possess utility for detecting functional perfusion deficits and provide unique insight into muscle tissue- and vascular-level characteristics of PAD patients. This review discusses the past, present, and emerging applications of hybrid nuclear imaging modalities in the evaluation and monitoring of patients with PAD.

Brazilian Society of Angiology and Vascular Surgery 2023 guidelines on the diabetic foot

The diabetic foot interacts with anatomical, vascular, and neurological factors that challenge clinical practice. This study aimed to compile the primary scientific evidence based on a review of the main guidelines, in addition to articles published on the Embase, Lilacs, and PubMed platforms. The European Society of Cardiology system was used to develop recommendation classes and levels of evidence. The themes were divided into six chapters (Chapter 1 - Prevention of foot ulcers in people with diabetes; Chapter 2 - Pressure relief from foot ulcers in people with diabetes; Chapter 3 -Classifications of diabetic foot ulcers; Chapter 4 - Foot and peripheral artery disease; Chapter 5 - Infection and the diabetic foot; Chapter 6 - Charcot's neuroarthropathy). This version of the Diabetic Foot Guidelines presents essential recommendations for the prevention, diagnosis, treatment, and follow-up of patients with diabetic foot, offering an objective guide for medical practice.

BedBiopsy: Diagnostic performance of bedside ultrasound-guided bone biopsies for the management of diabetic foot infection

OBJECTIVE

We aimed to assess the feasibility and diagnostic performance of ultrasound-guided bone biopsies at the bedside of diabetic patients admitted for suspected foot osteitis not requiring surgery.

RESEARCH DESIGN AND METHODS

In this retrospective monocentric study, we compared the performance of ultrasound-guided (n = 29 consecutive patients, Dec.2020-Oct.2022) versus surgical (n = 24 consecutive patients, Jan.2018-Nov.2020) bone biopsies at confirming or ruling out diabetic foot osteitis (primary outcome).

RESULTS

Patient characteristics were similar in the two intervention groups, including arteritis prevalence (62.3 %), SINBAD score, and wound location (phalanges 36 %, metatarsus 43 %, and calcaneus 21 %). However, the ultrasound-guided group was older (67 ± 11 versus 60 ± 13 years respectively, P = 0.047) and had more type 2 diabetes (97 % versus 75 %, P = 0.038). Diagnostic performance (i.e., capacity to confirm or rule out suspected osteitis) was similar for ultrasound-guided (28/29 cases: 25 confirmations, 3 invalidations) and surgical (24 confirmations/24) biopsies, P = 0.358. No biopsy-related side effect or complication was observed for either intervention, even for patients on antiaggregation and/or anticoagulation therapy. The mean (± standard deviation) time necessary to perform the biopsy was shorter in the ultrasound-guided group (2.6 ± 3.0 versus 7.2 ± 5.8 days, respectively, P < 0.001) and wound evolution at three months was more favorable (83.3 versus 41.2 %, P = 0.005) (94.4 % versus 66.7 %, respectively, patients with new surgical procedure within six months excluded; P = 0.055). Even though not statistically significant, healing rates in terms of wound and osteitis at six months were also better in the ultrasound-guided group (wound: 40.9 % versus 36.8 %; P = 0.790, and osteitis: 81.8 vs 55.6 % P = 0.071).

CONCLUSION

In diabetic patients with suspected foot osteitis not requiring surgery, bedside ultrasound-guided bone biopsies may constitute a promising alternative to surgical biopsies. This intervention provided excellent tolerance and microbiological documentation, short lead-times, and more favorable wound prognosis.

The Impact of Implementing a Diabetic Limb-Preservation Program on Amputation Outcomes at an Academic Institution in a Majority-Minority State

Background. Diabetic foot osteomyelitis may precede major limb amputations and lengthy hospital admission. These complications impact patients' morbidity and mortality. Healthcare institutions with dedicated limb-preservation teams realize reduced amputation rates and improved quality of care. This study evaluates the outcomes following the implementation of a rigorous diabetic limb-preservation program at an academic institution. Methods. Patients with diabetes admitted for osteomyelitis occurring below the knee were identified by ICD-10 codes and included for retrospective review. The number and type of amputations, bone biopsies, revascularizations, and hospital length of stay (LOS) were evaluated. Outcomes were compared using the high-low (Hi-Lo) amputation ratio for the 24 months preceding and the 24 months after the integration of a diabetic limb-preservation service. Results. The authors identified and included 337 patients admitted for diabetic foot osteomyelitis. In the 24-month period prior to program implementation, 140 patients were evaluated. In the 24-month period after program implementation, 197 patients were evaluated. The overall amputation rate decreased from 67.1% (n = 94) to 59.9% (n = 118) (P = .214). Major limb amputation rates significantly decreased from 32.9% (n = 46) to 12.7% (n = 25) (P = .001). Minor amputation rates significantly increased from 34.2% (n = 48) to 47.2% (n = 93) (P = .024). The Hi-Lo amputation ratio decreased from 0.96 to 0.27 (P < .001). The rate of obtaining bone biopsies increased from 32.1% (n = 45) to 72.1% (P < .001). The rate of revascularization increased from 10.7% (n = 15) to 15.2% (n = 30) (P = .299). Average hospital LOS decreased significantly from 11.6 days to 9.8 days (P = .044). Conclusion. After the implementation of a limb-preservation team, there was a precipitous drop in major limb amputations in favor of minor amputations. The average hospital LOS decreased. These findings demonstrated improved clinical care and outcomes in patients with lower extremity osteomyelitis and reinforce the importance of a diabetic foot-preservation service within healthcare institutions.

Is fluoroscopy-guided percutaneous bone biopsy of diabetic foot with suspected osteomyelitis worthwhile? A retrospective study

BACKGROUND

Diabetic foot infection, particularly osteomyelitis, is a major risk factor of amputation in persons with diabetes. Bone biopsy with microbial examination is considered the gold standard of diagnosis of osteomyelitis, providing information about the offending pathogens as well as their antibiotics susceptibility. This allows targeting of these pathogens with narrow spectrum antibiotics, potentially reducing emergence of antimicrobial resistance. Percutaneous fluoroscopy guided bone biopsy allows accurate and safe targeting of the affected bone.

METHODS

In a single tertiary medical institution and over 9 year period, we performed 170 percutaneous bone biopsies. We retrosepctively reviewed the medical record of these patients including patients' demographics, imaging and biopsy microbiology and pathollogic results.

RESULTS

Microbiological cultures of 80 samples (47.1%) were positive with 53.8% of the positive culture showed monomicrobial growth and the remaining were polymicrobial. Of the positive bone samples 71.3% grew Gram-positive bacteria. Staphylococcus aureus was the most frequently isolated pathogen from positive bone cultures with almost one third showing methicillin resistence. Enterococcus species were the most frequently isolated pathogens from polymicrobial samples. Enterobacteriaceae species were the most common Gram-negative pathogens and were more common in polymicrobial samples.

CONCLUSIONS

Percutaneous image-guided bone biopsy is a low-risk, minimally invasive procedure that can provide valuable information about microbial pathogens and therefore enable targeting these pathogens with narrow spectrum antibiotics.

Radiometal chelators for infection diagnostics

Infection of native tissues or implanted devices is common, but clinical diagnosis is frequently difficult and currently available noninvasive tests perform poorly. Immunocompromised individuals (for example transplant recipients, or those with cancer) are at increased risk. No imaging test in clinical use can specifically identify infection, or accurately differentiate bacterial from fungal infections. Commonly used [18F]fluorodeoxyglucose (18FDG) positron emission computed tomography (PET/CT) is sensitive for infection, but limited by poor specificity because increased glucose uptake may also indicate inflammation or malignancy. Furthermore, this tracer provides no indication of the type of infective agent (bacterial, fungal, or parasitic). Imaging tools that directly and specifically target microbial pathogens are highly desirable to improve noninvasive infection diagnosis and localization. A growing field of research is exploring the utility of radiometals and their chelators (siderophores), which are small molecules that bind radiometals and form a stable complex allowing sequestration by microbes. This radiometal-chelator complex can be directed to a specific microbial target in vivo, facilitating anatomical localization by PET or single photon emission computed tomography. Additionally, bifunctional chelators can further conjugate therapeutic molecules (e.g., peptides, antibiotics, antibodies) while still bound to desired radiometals, combining specific imaging with highly targeted antimicrobial therapy. These novel therapeutics may prove a useful complement to the armamentarium in the global fight against antimicrobial resistance. This review will highlight current state of infection imaging diagnostics and their limitations, strategies to develop infection-specific diagnostics, recent advances in radiometal-based chelators for microbial infection imaging, challenges, and future directions to improve targeted diagnostics and/or therapeutics.

Hybrid imaging of Diabetic Foot Infections

Diabetic foot infections, a common but diagnostically challenging clinical presentation, requires the difficult differentiation between soft tissue-only infection, diabetic neuropathic osteoarthropathy, osteomyelitis or a combination of these pathological processes. While there are clinical predictors for osteomyelitis and simple bedside tests available, imaging is often required for accurate diagnosis. A variety of anatomic and molecular imaging tests are in clinical use, each with its advantages and disadvantages. This review will provide an overview of the different available imaging modalities and their diagnostic criteria, emphasizing the role of hybrid imaging for the accurate diagnosis of osteomyelitis.

Diagnostic performance of quantitative Ga-SPECT/CT for patients with lower-limb osteomyelitis

BACKGROUND

Patients with lower-limb osteomyelitis (LLOM) may experience major adverse events, such as lower-leg amputations or death; therefore, early diagnosis and risk stratification are essential to improve outcomes. Ga-scintigraphy is commonly used for diagnosing inflammatory diseases. Although the diagnostic performance of planar and SPECT imaging for localized lesions is limited, SPECT/CT, which simultaneously acquires functional and anatomical definition, has resulted in significant improvements to diagnostic confidence. While quantitative Ga-SPECT/CT is an emerging approach to improve diagnoses, its diagnostic performance has not been sufficiently evaluated to date. Therefore, this study aimed to evaluate the diagnostic performance of Ga-SPECT/CT with quantitative analyses for patients with LLOM.

METHODS

A total of 103 consecutive patients suspected of LLOM between April 2012 and October 2016 were analyzed. All patients underwent Ga-scintigraphy with SPECT/CT imaging. Findings were assessed visually, with higher than background accumulation considered positive, and quantitatively, using Ga-SPECT/CT images to calculate the lesion-to-background ratio (LBR), the maximum standardized uptake value (SUVmax), and total lesion uptake (TLU). Diagnoses were confirmed using pathological examinations and patient outcomes, and diagnostic performances of planar, SPECT, and SPECT/CT images were compared. To evaluate prognostic performance, all patients were observed for 5 years for occurrences of major adverse events (MAE), defined as recurrence of osteomyelitis, major leg amputation, or fatal event. Multivariate Cox regression was performed to evaluate outcome factors.

RESULTS

The overall diagnoses indicated that 54 out of 103 patients had LLOM. LBR, SUVmax, and TLU were significantly higher in patients with LLOM (12.23 vs. 1.00, 4.85 vs. 1.34, and 68.77 vs. 8.63, respectively; p < 0.001). Sensitivity and specificity were 91% and 96% for SPECT/CT with LBR, 89% and 94% for SPECT/CT with SUVmax, and 91% and 92% for SPECT/CT with TLU, respectively. MAE occurred in 23 of 54 LLOM patients (43%). TLU was found to be an independent prognostic factor (p = 0.047).

CONCLUSIONS

Ga-SPECT/CT using quantitative parameters, namely LBR and TLU, had better diagnostic and prognostic performances for patients with LLOM compared to conventional imaging. The results suggest that Ga-SPECT/CT is a good alternative for diagnosing LLOM in countries where FDG-PET/CT is not commonly available.

Reliability and Safety of Bedside Blind Bone Biopsy Performed by a Diabetologist for the Diagnosis and Treatment of Diabetic Foot Osteomyelitis

OBJECTIVE

Bone biopsy (BB) performed by a surgeon or an interventional radiologist is recommended for suspicion of osteomyelitis underlying diabetic foot ulcer (DFU). To facilitate its practice, we developed a procedure allowing bedside blind bone biopsy (B4) by a diabetologist.

RESEARCH DESIGN AND METHODS

We conducted a three-step observational study consisting of a feasibility and safety phase (phase 1) to assess the success and side effects of B4, a validity phase (phase 2) to compare DFU outcomes between positive (B4+) and negative (B4-) bone cultures, and a performance phase (phase 3) to compare B4 with the conventional surgical or radiological procedure basic bone biopsy (B3). Primary end points were the presence of bone tissue (phase 1) and complete DFU healing with exclusive medical treatment at 12 months (phases 2 and 3).

RESULTS

In phase 1, 37 consecutive patients with clinical and/or radiological suspicion of DFU osteomyelitis underwent B4. Bone tissue was collected in all patients with few side effects. In phase 2, a B4+ bone culture was found in 40 of 79 (50.6%) participants. Among B4+ patients, complete wound healing after treatment was 57.5%. No statistical difference was observed with patients with B4- bone culture not treated with antibiotics (71.8%, P = 0.18). In phase 3, the proportion of patients with positive BB was lower in B4 (40 of 79, 50.6%) than in B3 (34 of 44, 77.3%, P < 0.01). However, complete healing was similar (64.6% vs. 54.6%, P = 0.28). No difference in rate of culture contamination was observed.

CONCLUSIONS

B4 is a simple, safe, and efficient procedure for the diagnosis of DFU osteomyelitis with a similar proportion of healing to conventional BB.

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.

Clinical Outcomes of Foot Infections in Patients Without Diabetes

The aim of this study was to report clinical outcomes of moderate and severe foot infections in patients without diabetes. Medical records of 88 nondiabetic patients with foot infections treated at a safety net hospital were retrospectively reviewed. Patients were grouped by the presence of soft-tissue infection (STI) or osteomyelitis (OM). The diagnosis of OM was determined by positive bone culture or histopathology. STIs were defined by negative bone biopsy or negative imaging with magnetic resonance imaging or computed tomography/dual-modality radiolabeled white blood cell single-photon emission computed tomography. Patient outcomes were recorded ≤1 year after admission. Eighty-eight nondiabetic patients admitted to our institution for moderate or severe foot infections were included, 45 OM and 43 STI. No differences were noted in patient characteristics except that OM patients had a higher prevalence of neuropathy (66.7% versus 39.5%, p = .02). OM patients required surgery more often (97.8% versus 67.4%, p < .01), a greater number of surgeries (2.0 ± 1.2 versus 1.4 ± 1.3, p = .02), and more amputations (75.6% versus 11.6%, p < .01) than STI patients. OM patients had a higher proportion of wounds that healed (82.2% versus 62.8%, p = .04). There were no significant differences in reinfection (35.6% versus 25.6%, p = .36), foot-related readmission to hospital (35.6% versus 23.3%, p = .25), or total duration of antibiotics (13.9 ± 10.2 versus 13.5 ± 12.9, p = .87) between OM and STI patients. In conclusion, OM patients required more surgeries and amputations than patients with STIs; however, they had similar rates of reinfection and readmission within a year after the index hospitalization.

Is 67gallium dead? A retrospective review of 67gallium imaging in a single tertiary referral centre

BACKGROUND

[67Ga]Ga-citrate scanning has been used to investigate patients with known or suspected infection for over 50 years, continuing to maintain a clinical niche in many centres. The introduction of single photon emission tomography/computed tomography (SPECT/CT) in addition to planar imaging has improved the specificity of diagnosis.

AIM

To examine the experience of modern [67Ga]Ga-citrate scanning in a single tertiary referral centre, considering the diagnostic yield of the study.

METHODS

A retrospective audit was undertaken of 100 consecutive [67Ga]Ga-citrate scans at Royal North Shore Hospital, Sydney. Recorded information included patient demographics, clinical information/history, and primary and secondary diagnoses. Subgroup analyses included patients with a confirmed diagnosis of infection or a suspected diagnosis of infection.

RESULTS

The median age of patients was 68.5 years. Totally, 39/100 patients undergoing [67Ga]Ga-citrate scanning presented with a confirmed site of infection, with 2/6 patients with infective endocarditis and 5/12 patients with bacteraemia diagnosed with an additional, previously unknown, site of active infection (compared to 1/21 patients without documented bacteraemia). 61/100 patients did not have a confirmed site of infection before [67Ga]Ga-citrate scan (as per clinical history). 34/61 of these patients had a positive scan result for active infection/inflammation. Of 20 patients with a positive blood culture but no suspected site of infection, the source was identified in 9.

CONCLUSION

[67Ga]Ga-citrate has diagnostic value in the evaluation of complex patients with high-risk infection. High diagnostic yield is demonstrated in patients with bacteraemia with or without a confirmed site of infection, particularly when combined with SPECT/CT.

Imaging tests for the detection of osteomyelitis: a systematic review

BACKGROUND

Osteomyelitis is an infection of the bone. Medical imaging tests, such as radiography, ultrasound, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and positron emission tomography (PET), are often used to diagnose osteomyelitis.

OBJECTIVES

To systematically review the evidence on the diagnostic accuracy, inter-rater reliability and implementation of imaging tests to diagnose osteomyelitis.

DATA SOURCES

We conducted a systematic review of imaging tests to diagnose osteomyelitis. We searched MEDLINE and other databases from inception to July 2018.

REVIEW METHODS

Risk of bias was assessed with QUADAS-2 [quality assessment of diagnostic accuracy studies (version 2)]. Diagnostic accuracy was assessed using bivariate regression models. Imaging tests were compared. Subgroup analyses were performed based on the location and nature of the suspected osteomyelitis. Studies of children, inter-rater reliability and implementation outcomes were synthesised narratively.

RESULTS

Eighty-one studies were included (diagnostic accuracy: 77 studies; inter-rater reliability: 11 studies; implementation: one study; some studies were included in two reviews). One-quarter of diagnostic accuracy studies were rated as being at a high risk of bias. In adults, MRI had high diagnostic accuracy [95.6% sensitivity, 95% confidence interval (CI) 92.4% to 97.5%; 80.7% specificity, 95% CI 70.8% to 87.8%]. PET also had high accuracy (85.1% sensitivity, 95% CI 71.5% to 92.9%; 92.8% specificity, 95% CI 83.0% to 97.1%), as did SPECT (95.1% sensitivity, 95% CI 87.8% to 98.1%; 82.0% specificity, 95% CI 61.5% to 92.8%). There was similar diagnostic performance with MRI, PET and SPECT. Scintigraphy (83.6% sensitivity, 95% CI 71.8% to 91.1%; 70.6% specificity, 57.7% to 80.8%), computed tomography (69.7% sensitivity, 95% CI 40.1% to 88.7%; 90.2% specificity, 95% CI 57.6% to 98.4%) and radiography (70.4% sensitivity, 95% CI 61.6% to 77.8%; 81.5% specificity, 95% CI 69.6% to 89.5%) all had generally inferior diagnostic accuracy. Technetium-99m hexamethylpropyleneamine oxime white blood cell scintigraphy (87.3% sensitivity, 95% CI 75.1% to 94.0%; 94.7% specificity, 95% CI 84.9% to 98.3%) had higher diagnostic accuracy, similar to that of PET or MRI. There was no evidence that diagnostic accuracy varied by scan location or cause of osteomyelitis, although data on many scan locations were limited. Diagnostic accuracy in diabetic foot patients was similar to the overall results. Only three studies in children were identified; results were too limited to draw any conclusions. Eleven studies evaluated inter-rater reliability. MRI had acceptable inter-rater reliability. We found only one study on test implementation and no evidence on patient preferences or cost-effectiveness of imaging tests for osteomyelitis.

LIMITATIONS

Most studies included < 50 participants and were poorly reported. There was limited evidence for children, ultrasonography and on clinical factors other than diagnostic accuracy.

CONCLUSIONS

Osteomyelitis is reliably diagnosed by MRI, PET and SPECT. No clear reason to prefer one test over the other in terms of diagnostic accuracy was identified. The wider availability of MRI machines, and the fact that MRI does not expose patients to harmful ionising radiation, may mean that MRI is preferable in most cases. Diagnostic accuracy does not appear to vary with the potential cause of osteomyelitis or with the body part scanned. Considerable uncertainty remains over the diagnostic accuracy of imaging tests in children. Studies of diagnostic accuracy in children, particularly using MRI and ultrasound, are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017068511.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 61. See the NIHR Journals Library website for further project information.

Percutaneous Bone Biopsy for Diabetic Foot Osteomyelitis: A Systematic Review and Meta-Analysis

Background

Diabetes is the leading cause of lower extremity nontraumatic amputation globally, and diabetic foot osteomyelitis (DFO) is usually the terminal event before limb loss. Although guidelines recommend percutaneous bone biopsy (PBB) for microbiological diagnosis of DFO in several common scenarios, it is unclear how frequently PBBs yield positive cultures and whether they cause harm or improve outcomes.

Methods

We searched the PubMed, EMBASE, and Cochrane Trials databases for articles in any language published up to December 31, 2019, reporting the frequency of culture-positive PBBs. We calculated the pooled proportion of culture-positive PBBs using a random-effects meta-analysis model and reported on PBB-related adverse events, DFO outcomes, and antibiotic adjustment based on PBB culture results where available.

Results

Among 861 articles, 11 studies met inclusion criteria and included 780 patients with 837 PBBs. Mean age ranged between 56.6 and 71.0 years old. The proportion of males ranged from 62% to 86%. All studies were longitudinal observational cohorts, and 10 were from Europe. The range of culture-positive PBBs was 56%-99%, and the pooled proportion of PBBs with a positive culture was 84% (95% confidence interval, 73%-91%). There was heterogeneity between studies and no consistency in definitions used to define adverse events. Impact of PBB on DFO outcomes or antibiotic management were seldom reported.

Conclusions

This meta-analysis suggests PBBs have a high yield of culture-positive results. However, this is an understudied topic, especially in low- and middle-income countries, and the current literature provides very limited data regarding procedure safety and impact on clinical outcomes or antibiotic management.

Imaging for detection of osteomyelitis in people with diabetic foot ulcers: A systematic review and meta-analysis

BACKGROUND

Osteomyelitis is an infection of the bone which can occur in people with diabetic foot ulcers. It can be diagnosed using X-rays, ultrasound, scintigraphy, magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission tomography (PET).

OBJECTIVES

To review the evidence on the diagnostic accuracy of imaging tests to diagnose osteomyelitis in people with diabetic foot ulcers.

METHODS

We conducted a systematic review and meta-analysis. MEDLINE, EMBASE and other databases were searched to July 2018. Risk of bias was evaluated. Diagnostic accuracy was estimated using bivariate meta-analyses.

RESULTS

Thirty-six studies were included in the meta-analysis. Eight studies were at high risk of bias MRI had high diagnostic accuracy (22 studies: 96.4 % sensitivity (95 % CI 90.7-98.7); 83.8 % specificity (76.0-89.5)). PET scans also had high accuracy (6 studies: 84.3 % sensitivity (52.8-96.3); 92.8 % specificity (75.7-98.2)), and possibly also SPECT, but with few studies (3 studies: 95.6 % sensitivity (76.0-99.3); 55.1 % specificity (19.3-86.3)). Scintigraphy (17 studies: 84.2 % sensitivity (76.8-89.6); 67.7 % specificity (56.2-77.4)), and X-rays (16 studies: 61.9 % sensitivity (50.5-72.1); 78.3 % specificity (62.9-88.5)) had generally inferior diagnostic accuracy.

CONCLUSIONS

MRI and PET both reliably diagnose osteomyelitis in diabetic foot ulcer patients. SPECT may also have good diagnostic accuracy, although evidence is limited. This review confirms most current guidelines, showing that MRI may be the preferable test in most cases, given its wider availability and the lack of potentially harmful ionising radiation.

Gallium-67 SPECT-CT for the evaluation of head and neck: preliminary study on maximum standardised uptake value in lesions, and in the parotid and submandibular glands

Purpose

The aim of this study was to investigate the gallium-67 (⁶⁷Ga) single-photon emission-computed tomography (SPECT-CT) for the evaluation of head and neck, especially maximum standardised uptake value (SUV_max) in lesions, and in the parotid and submandibular glands.

Material and methods

Fourteen patients with head and neck lesions who underwent SPECT-CT at 72 hours after injection of ⁶⁷Ga were included in this study. The ⁶⁷Ga SPECT-CT parameters SUV_max were compared between the parotid glands and submandibular glands. Statistical analyses for the SUV_max were performed by Mann-Whitney U test. A p value lower than 0.05 was considered as statistically significant.

Results

Of all 14 patients, ⁶⁷Ga SPECT-CT was positive for two cases (one malignant lymphoma and one osteomyelitis). The SUV_max for malignant lymphoma and osteomyelitis were 11.21 and 10.95, respectively. Furthermore, SUV_max for parotid glands and submandibular glands of all patients were 4.86 ± 1.89 and 4.64 ± 1.64, respectively (p = 0.694).

Conclusions

This study investigated the ⁶⁷Ga SPECT-CT for the evaluation of head and neck, especially SUV_max of lesions, and the parotid and submandibular glands. ⁶⁷Ga SPECT-CT may be an effective technique for the evaluation of maxillofacial lesions.

Nuclear Medicine for the Orthopedic Foot and Ankle Surgeon

Nuclear medicine has been widely applied as a diagnostic tool for orthopedic foot and ankle pathology. Although its indications have diminished with improvements in and the availability of magnetic resonance imaging, nuclear medicine still has a significant and valuable role. The present article offers a comprehensive and current review of the most common nuclear imaging modalities for the orthopedic foot and ankle surgeon. Methods discussed include bone scintigraphy, gallium citrate scintigraphy, labeled-leukocyte scintigraphy, and single-photon emission computed tomography (SPECT). We review the indications and utility of these techniques as they pertain to specific foot and ankle conditions, including osteomyelitis, stress fractures, talar osteochondral lesions, complex regional pain syndrome, oncology, plantar fasciitis, and the painful total ankle arthroplasty. We conclude with a discussion of our approach to nuclear medicine with illustrative cases. Level of Evidence: Level V, expert opinion.

Diagnosing diabetic foot osteomyelitis

Bone involvement during an infection of the diabetic foot represents a serious complication associated with a high risk of amputation, prolonged antibiotic treatment and hospitalization. Diabetic foot osteomyelitis (DFOs) require a multidisciplinary approach given the usual complexity of these situations. DFO should be suspected in most cases especially in the most severe forms of soft tissue diabetic foot infections (DFIs) where the prevalence of bone infection may be up to 60%. Suspicion is based on clinical signs in particular a positive probe-to-bone (PTB) test, elevated inflammatory biomarkers especially erythrocyte sedimentation rate and abnormal imaging assessment using plain X-ray as a first-line choice. The combination of PTB test with plain X-ray has proven effective in the diagnosis of DFO. The confirmation (definite) diagnosis of DFO is based on the results of a bone sample examination obtained by either surgical or percutaneous biopsy. Sophisticated imaging examinations such as Magnetic Resonance Imaging (MRI) and nuclear imaging techniques are useful where doubt persists after first-line imaging assessment. These techniques may also help localize the bone infection site and increase the diagnostic performance of percutaneous bone biopsy. The quality of the microbiological documentation of DFO is likely to improve the adequacy of the antimicrobial therapy especially when medical (ie, no surgical resection of the infected bone tissues) is considered. The use of new (molecular) techniques for the identification of the bone pathogens have not yet proven superiority on classic cultural techniques for the management of such patients.

Diagnosis of infection in the foot in diabetes: a systematic review

BACKGROUND

Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potentially mortality and present formidable challenges in surgical and antimicrobial treatment.

METHODS

In June 2018, we searched the literature using PuEbMed and EMBASE for published studies on the diagnosis of diabetic foot infection. On the basis of predetermined criteria, we reviewed prospective controlled, as well as noncontrolled, studies in any language, seeking translations for those not in English. We then developed evidence statements on the basis of the included papers.

RESULTS

From the 4242 records screened, we selected 35 papers that met our inclusion criteria. The quality of all but one of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot scheme correlates with the patient's likelihood of ulcer healing, of lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers are supportive, but not diagnostic, of soft tissue or bone infection. In patients with suspected diabetic foot osteomyelitis, both a positive probe-to-bone test and an elevated erythrocyte sedimentation rate are strongly associated with its presence. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis, but advanced imaging methods help in cases when either the diagnosis or the localization of infection is uncertain.

CONCLUSION

The results of this first reported systematic review on the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is a need for more prospective controlled studies of high quality.

Guidelines on the diagnosis and treatment of foot infection in persons with diabetes (IWGDF 2019 update)

The International Working Group on the Diabetic Foot (IWGDF) has published evidence-based guidelines on the prevention and management of diabetic foot disease since 1999. This guideline is on the diagnosis and treatment of foot infection in persons with diabetes and updates the 2015 IWGDF infection guideline. On the basis of patient, intervention, comparison, outcomes (PICOs) developed by the infection committee, in conjunction with internal and external reviewers and consultants, and on systematic reviews the committee conducted on the diagnosis of infection (new) and treatment of infection (updated from 2015), we offer 27 recommendations. These cover various aspects of diagnosing soft tissue and bone infection, including the classification scheme for diagnosing infection and its severity. Of note, we have updated this scheme for the first time since we developed it 15 years ago. We also review the microbiology of diabetic foot infections, including how to collect samples and to process them to identify causative pathogens. Finally, we discuss the approach to treating diabetic foot infections, including selecting appropriate empiric and definitive antimicrobial therapy for soft tissue and for bone infections, when and how to approach surgical treatment, and which adjunctive treatments we think are or are not useful for the infectious aspects of diabetic foot problems. For this version of the guideline, we also updated four tables and one figure from the 2016 guideline. We think that following the principles of diagnosing and treating diabetic foot infections outlined in this guideline can help clinicians to provide better care for these patients.

Feasibility of Percutaneous Bone Biopsy as Part of the Management of Diabetic Foot Osteomyelitis in a 100% Neuropathic, Grade 3 IDSA/IWGDF Population on an Outpatient Basis

The present study aimed to evaluate the feasibility of percutaneous bone biopsy in an ambulatory setting as part of the management of diabetic foot osteomyelitis (DFO) on an outpatient basis. DFO may complicate some cases of apparently nonsevere foot infections in patients with diabetes and greatly increase the risk of a lower extremity amputation. It has been suggested that bone culture-based antibiotic therapy is a predictive factor of success in patients with diabetes treated nonsurgically for osteomyelitis of the foot. It is recommended to identify the causative microorganism(s) by the means of either a surgical or percutaneous bone biopsy taken appropriately to select the proper antibiotic therapy. Percutaneous bone biopsy in patients not requiring surgery is, however, not performed in everyday practice as it should be according to the current recommendations. In the present retrospective study, we report a series of 23 consecutive patients with a suspicion of DFO in whom 28 bone samples were collected by percutaneous biopsy at the bedside in an outpatient setting. The percentage of positive cultures was in accordance with that reported in the literature. The mean number of isolates per specimen was 1.04. After a mean 12-month follow-up, the remission was almost of 78%. No adverse event related to the bone biopsy was noted. After a 1-year follow-up, no recurrence was recorded among the patients in remission. The results of the present study suggest that bedside percutaneous bone biopsy performed in the ambulatory setting is a valuable and safe tool in the management of DFO on an outpatient basis.

Diagnosis and Management of Osteomyelitis Associated With Stage 4 Pressure Ulcers: Report of a Query to the Emerging Infections Network of the Infectious Diseases Society of America

Background

Few studies exist to guide the management of patients with stage 4 pressure ulcers with possible underlying osteomyelitis. We hypothesized that infectious disease (ID) physicians would vary widely in their approach to such patients.

Methods

The Emerging Infections Network distributed a 10-question electronic survey in 2018 to 1332 adult ID physicians in different practice settings to determine their approach to such patients.

Results

Of the 558 respondents (response rate: 42%), 17% had managed no such patient in the past year. Of the remaining 464 respondents, 60% usually felt confident in diagnosing osteomyelitis; the strongest clinical indicator of osteomyelitis reported was palpable or visible bone at the ulcer base. Approaches to diagnosing osteomyelitis in patients with visible and palpable bone varied: 41% of respondents would assume osteomyelitis, 27% would attempt pressure off-loading first, and 22% would perform diagnostic testing immediately. Preferred tests for osteomyelitis were bone biopsy (for culture and histopathology) and magnetic resonance imaging. Respondents differed widely on favored route(s) (intravenous, oral, or both) and duration of antimicrobial therapy but would treat longer in the absence, vs presence, of full surgical debridement (P < .001). Overall, 62% of respondents opined that osteomyelitis under stage 4 pressure ulcers is usually or almost always treated excessively, and most (59%) suggested multiple topics for future research.

Conclusions

Regarding osteomyelitis underlying stage 4 pressure ulcers, ID physicians reported widely divergent diagnostic and treatment approaches. Most of the reported practice is not supported by the available evidence, which is quite limited and of low quality.

Clinical Applications for Radiotracer Imaging of Lower Extremity Peripheral Arterial Disease and Critical Limb Ischemia

Peripheral arterial disease (PAD) is an atherosclerotic occlusive disease of the non-coronary vessels that is characterized by lower extremity tissue ischemia, claudication, increased prevalence of lower extremity wounds and amputations, and impaired quality of life. Critical limb ischemia (CLI) represents the severe stage of PAD and is associated with additional risk for wound formation, amputation, and premature death. Standard clinical tools utilized for assessing PAD and CLI primarily focus on anatomical evaluation of peripheral vascular lesions or hemodynamic assessment of the peripheral circulation. Evaluation of underlying pathophysiology has traditionally been achieved by radiotracer-based imaging, with many clinical investigations focusing on imaging of skeletal muscle perfusion and cases of foot infection/inflammation such as osteomyelitis and Charcot neuropathic osteoarthropathy. As advancements in hybrid imaging systems and radiotracers continue to evolve, opportunities for molecular imaging of PAD and CLI are also emerging that may offer novel insight into associated complications such as peripheral atherosclerosis, alterations in skeletal muscle metabolism, and peripheral neuropathy. This review summarizes the pros and cons of radiotracer-based techniques that have been utilized in the clinical environment for evaluating lower extremity ischemia and common pathologies associated with PAD and CLI.

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

PURPOSE

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

METHODS

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

CONCLUSIONS

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

Comparison between squamous cell carcinoma and inflammatory diseases of the oral and maxillofacial region using gallium-67 scintigraphy with computed tomography and magnetic resonance imaging

Purpose

This study aimed to compare squamous cell carcinoma (SCC) with inflammatory diseases of the oral and maxillofacial region using gallium 67 (⁶⁷Ga) scintigraphy with computed tomography (CT) and magnetic resonance imaging (MRI).

Material and methods

Seventy patients with SCC and 15 patients with inflammatory diseases of the oral and maxillofacial region underwent ⁶⁷Ga scintigraphy with CT and MRI. A comparison between imaging features of ⁶⁷Ga scintigraphy, CT, and MRI and lesions was performed with the Pearson’s chi-squared test.

Results

⁶⁷Ga scintigraphy was positive for 25 of 39 patients with SCC positive on CT and/or MRI (64.1%) and for 13 of 15 patients with inflammatory diseases positive on CT and/or MRI (86.7%). The detection of inflammatory diseases with ⁶⁷Ga scintigraphy was higher than that of SCC (p = 0.104).

Conclusions

This study compared SCC with inflammatory diseases of the oral and maxillofacial region using ⁶⁷Ga scintigraphy with CT and MRI. ⁶⁷Ga scintigraphy is an effective technique for detection of inflammatory diseases of the oral and maxillofacial region.

Modern management of diabetic foot osteomyelitis. The when, how and why of conservative approaches

INTRODUCTION

Diabetic foot osteomyelitis (DFO) has long been considered a complex infection that is both difficult to diagnose and treat, and is associated with a high rate of relapse and limb loss. Areas covered: DFO can usually be diagnosed by a combination of clinical evaluation, serum inflammatory markers and plain X-ray. When the results of these procedures are negative or contradictory, advanced imaging tests or bone biopsy may be necessary. Staphylococcus aureus remains the most frequent microorganism isolated from bone specimens, but infection is often polymicrobial. Antibiotic therapy, preferably with oral agents guided by results of bone culture, for a duration of no more than six weeks, appears to be as safe and effective as surgery in cases of uncomplicated forefoot DFO. Surgery (which should be limb-sparing when possible) is always required for DFO accompanied by necrotizing fasciitis, deep abscess, gangrene or in cases not responding (either clinically or radiographically) to apparently appropriate antibiotic treatment. Expert commentary: Research in the past decade has improved diagnosis and treatment of DFO, and most cases can now be managed with a 'conservative' approach, defined as treatment either exclusively with antibiotics or with surgery removing as little bone and soft tissue as necessary.

Application of white blood cell SPECT/CT to predict remission after a 6 or 12 week course of antibiotic treatment for diabetic foot osteomyelitis

AIMS/HYPOTHESIS

Diabetic foot osteomyelitis is a major risk factor for amputation. Medical treatment allows remission in 53-82% of cases. However, the optimal duration of antibiotic therapy remains controversial as a validated marker of osteomyelitis remission is lacking. The aim of this cohort study was to assess prospectively the remission rate of diabetic foot osteomyelitis medically treated using white blood cell (WBC)-single-photon emission computed tomography (SPECT)/computed tomography (CT) as a predictive marker of remission.

METHODS

Individuals with diabetic foot osteomyelitis that was non-surgically treated between April 2014 and December 2015 were included. All participants were treated with antibiotics alone. WBC-SPECT/CT was performed at 6 weeks and antibiotic treatment discontinued if the clinical signs of soft-tissue infection had resolved and there was no abnormal uptake of labelled WBCs. Treatment was otherwise continued for a total of 12 weeks and then discontinued. For these individuals, another WBC-SPECT/CT was performed at 12 weeks. Remission was defined as the absence of recurrence of osteomyelitis at the same location at 1 year.

RESULTS

Forty-five individuals were included; overall remission rate was 84% at 1 year. A 6 week course of antibiotics was used in 23 participants, 22 of whom were in remission at 1 year (96%); a 12 week course was used for 22 participants, 16 of whom were in remission at 1 year (73%). Sensitivity of WBC-SPECT/CT at 12 weeks was 100%, specificity 56%, positive predictive value 46% and negative predictive value 100%.

CONCLUSIONS/INTERPRETATION

The study suggests that WBC-SPECT/CT could predict remission at the end of antibiotic treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02927678.

Osteomyelitis of the foot: non-surgical management, SPECT/CT scanning and minimising the duration of antibiotic use

In a paper in this issue of Diabetologia (DOI: https://doi.org/10.1007/s00125-017-4417-x ), Vouillarmet and colleagues have explored the use of single-photon emission computed tomography (SPECT)/computed tomography (CT) to define remission during non-surgical management of osteomyelitis of the foot. Their experience in a non-controlled observational study of 45 individuals was that a negative white blood cell-SPECT/CT scan is a reliable marker of remission, while a positive scan at the end of antibiotic treatment may be relatively useful in the prediction of future short- to medium-term relapse. These findings and conclusions are discussed in the light of current uncertainties relating to the diagnosis of bone infection and the lack of any tested measure that can be used to indicate either its presence or its persistence. In this respect, it is concluded that the value of this approach, and in which population, remains to be clearly established.

Diabetic foot infection: Antibiotic therapy and good practice recommendations

BACKGROUND

Healthcare events related to diabetic foot disease carry a burden of morbidity, mortality and economic cost. Prompt identification of clinical infection with appropriate tissue sampling limits use of broad spectrum empirical antibiotics and improves antibiotic stewardship. Staphylococcus aureus remains the commonest infecting organism and high-dose flucloxacillin remains the empirical antibiotic of choice for antibiotic naïve patients. Barriers to microbe-specific treatment include: adequate tissue sampling, delays in culture results, drug allergies and the emergence of multidrug-resistant organisms which can complicate the choice of targeted antibiotics. Even appropriate antibiotic treatment carries a risk of adverse events including the selection of resistant organisms.

AIMS

Multidisciplinary clinical assessment of a diabetic foot infection is supported by the use of appropriate imaging modalities and deep tissue sampling, both of which are encouraged to enhance sampling accuracy. Narrow-spectrum, high dose, short duration antimicrobial therapy is ideal. Further clarity in these areas would be of benefit to clinicians involved in management of diabetic foot infections.

METHODS

A combination of literature review with expert discussion was used to generate consensus on management of diabetic foot infection, with a specific focus on empirical antimicrobial therapy.

RESULTS

Gram positive organisms represent the commonest pathogens in diabetic foot infection. However there are developing challenges in antimicrobial resistance and antibiotic availability.

DISCUSSION

Recommendations for empirical therapy, including the choice of alternative oral agents and use of outpatient antibiotics would be of benefit to those involved in diabetic foot care.

CONCLUSION

This paper provides advice on empirical antibiotic therapy that may be used as a framework for local guideline development to support clinicians in the management of diabetic foot infection.

Multimodality Imaging Approaches for Evaluating Traumatic Extremity Injuries: Implications for Military Medicine

Significance: Military service members are susceptible to traumatic extremity injuries that often result in limb loss. Tremendous efforts have been made to improve medical treatment that supports residual limb function and health. Despite recent improvements in treatment and novel prosthetic devices, many patients experience a wide range of clinical problems within residual limbs that can negatively impact the progress of rehabilitation programs while also impairing functional capacity and overall quality of life. Recent Advances: In addition to existing standard imaging modalities that are used for clinical evaluation of patients suffering from traumatic extremity injury, novel noninvasive imaging techniques are in development that may facilitate rapid and sensitive assessment of various aspects of traumatic extremity injuries and residual limb health. Critical Issues: Despite recent advances, there remains a clinical need for noninvasive quantitative imaging techniques that are capable of providing rapid objective assessments of residual limb health at the time of initial presentation as well as after various forms of medical treatment. Future Directions: Ongoing development of imaging techniques that allow for assessment of anatomical and physiological characteristics of extremities exposed to traumatic injury should greatly enhance the quality of patient care and assist in optimizing clinical outcomes.

Diagnostic and therapeutic update on diabetic foot osteomyelitis

Diabetic foot osteomyelitis (DFO) is the most common infection associated to diabetic foot ulcers (DFU). This review is designed to provide an update on the diagnosis and treatment of DFO based on an analysis of MEDLINE through PubMed using as search criterion "Diabetic Foot Osteomyelitis". Authors have included in this review the most relevant manuscripts regarding diagnosis and treatment of DFO. After review and critical analysis of publications, it may be concluded that diagnosis of DFO is not simple because of its heterogeneous presentation. Clinical inflammatory signs, probe-to-bone test, and plain X-rays are postulated as the basic tests for clinical diagnosis when DFO is suspected. Diagnosis should be supported by laboratory tests, of which ESR (>70mm/h) has been shown to be most precise. MRI is the most accurate imaging test, especially for differential diagnosis with Charcot foot. Pathogen isolation by bone culture is essential when the patient is treated with ATB only. Medical or surgical treatment should be based on the clinical characteristics of the patient and the lesion. Surgery should always be an option if medical treatment fails.

Radionuclide Imaging of Musculoskeletal Infection: A Review

There are numerous imaging tests for diagnosing musculoskeletal infection. Radiographs are routinely performed, because even when not diagnostic, they provide an anatomic overview of the region of interest that could influence subsequent procedure selection and interpretation. MRI is sensitive and provides superb anatomic detail. Bone scintigraphy accurately diagnoses osteomyelitis in bones not affected by underlying conditions. (67)Ga is used primarily for spondylodiskitis. Although in vitro labeled leukocyte imaging is the radionuclide test of choice for complicating osteomyelitis such as diabetic pedal osteomyelitis and prosthetic joint infection, it is not useful for spondylodiskitis. Antigranulocyte antibodies and antibody fragments have limitations and are not widely available. (111)In-biotin is useful for spondylodiskitis. Radiolabeled synthetic fragments of the antimicrobial peptide ubiquicidin are promising infection-specific agents. (18)F-FDG is the radiopharmaceutical of choice for spondylodiskitis. Its role in diabetic pedal osteomyelitis and prosthetic joint infection is not established. Preliminary data suggest (68)Ga may be useful in musculoskeletal infection. (124)I-fialuridine initially showed promise as an infection-specific radiopharmaceutical, but subsequent investigations were disappointing. The development of PET/CT and SPECT/CT imaging systems, which combine anatomic and functional imaging, has revolutionized diagnostic imaging. These hybrid systems are redefining the diagnostic workup of patients with suspected or known infection and inflammation by improving diagnostic accuracy and influencing patient management.

Neuropathic osteoarthropathy with and without superimposed osteomyelitis in patients with a diabetic foot

Soft tissue and bone infection involving the foot is one of the most common long-term complications of diabetes mellitus, implying a serious impairment in quality of life for patients in the advanced stages of the disease. Neuropathic osteoarthropathy often coexists and differentiating between these two entities is commonly challenging, but crucial, as the management may differ substantially. The importance of correct diagnosis cannot be understated and effective management requires a multidisciplinary approach owing to the complicated nature of therapy in such patients. A missed diagnosis has a high likelihood of major morbidity for the patient, including limb amputation, and over-diagnosis results in a great socioeconomic challenge for healthcare systems, the over-utilization of healthcare resources, and the unwise use of antibiotics. Diagnosis is largely based on clinical signs supplemented by various imaging modalities such as radiography, MR imaging, and hybrid imaging techniques such as F-18 fluorodeoxyglucose-positron emission tomography. In the interests of the management of diabetic foot complications, this review article is aimed on the one hand at providing radiologists with important clinical knowledge, and on the other hand to equip clinicians with relevant radiological semiotics.

The value of inflammatory markers to diagnose and monitor diabetic foot osteomyelitis

In this study, we assessed the effectiveness of inflammatory markers to diagnose and monitor the treatment of osteomyelitis in the diabetic foot. We evaluated 35 consecutive patients admitted to our hospital with infected foot ulcers. Patients were divided in two groups based on the results of bone culture and histopathology: osteomyelitis and no osteomyelitis. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor alpha (TNFα), monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1 alpha (MIP1α) were measured at baseline after 3 and 6 weeks of standard therapy. PCT levels in the osteomyelitis group were significantly higher at baseline than in the group with no osteomyelitis (P = 0·049). There were no significant differences between the two groups in the levels of the other markers. CRP, ESR, PCT and IL-6 levels significantly declined in the group with osteomyelitis after starting therapy, while MCP-1 increased (P = 0·002). TNFα and MIP1α levels were below range in 80 out of 97 samples and therefore not reported. Our results suggest that PCT might be useful to distinguish osteomyelitis in infected foot ulcers. CRP, ESR, PCT and IL-6 are valuable when monitoring the effect of therapy.

Radionuclide imaging of osteomyelitis

Radionuclide procedures frequently are performed as part of the diagnostic workup of osteomyelitis. Bone scintigraphy accurately diagnoses osteomyelitis in bones not affected by underlying conditions. Degenerative joint disease, fracture, and orthopedic hardware decrease the specificity of the bone scan, making it less useful in these situations. Gallium-67 scintigraphy was often used as an adjunct to bone scintigraphy for diagnosing osteomyelitis. However, now it is used primarily for spinal infections when (18)F-FDG imaging cannot be performed. Except for the spine, in vitro-labeled leukocyte imaging is the nuclear medicine test of choice for diagnosing complicating osteomyelitis. Leukocytes accumulate in bone marrow as well as in infection. Performing complementary bone marrow imaging with (99m)Tc-sulfur colloid facilitates the differentiation between osteomyelitis and normal marrow and improves test overall accuracy. Antigranulocyte antibodies and antibody fragments, such as (99m)Tc-besilesomab and (99m)Tc-sulesomab, were developed to eliminate the disadvantages associated with in vitro-labeled leukocytes. These agents, however, have their own shortcomings and are not widely available. As biotin is used as a growth factor by certain bacteria, (111)In-biotin is useful to diagnose spinal infections. Radiolabeled synthetic fragments of ubiquicidin, a naturally occurring human antimicrobial peptide that targets bacteria, can differentiate infection from sterile inflammation and may be useful to monitor response to treatment. (18)F-FDG is extremely useful in the diagnostic workup of osteomyelitis. Sensitivity in excess of 95% and specificity ranging from 75%-99% have been reported. (18)F-FDG is the radionuclide test of choice for spinal infection. The test is sensitive, with a high negative predictive value, and reliably differentiates degenerative from infectious vertebral body end-plate abnormalities. Data on the accuracy of (18)F-FDG for diagnosing diabetic pedal osteomyelitis are contradictory, and its role for this indication remains to be determined. Initial investigations suggested that (18)F-FDG accurately diagnoses prosthetic joint infection; more recent data indicate that it cannot differentiate infection from other causes of prosthetic failure. Preliminary data on the PET agents gallium-68 and iodine-124 fialuridine indicate that these agents may have a role in diagnosing osteomyelitis.

Challenges in diagnosing infection in the diabetic foot

Diagnosing the presence of infection in the foot of a patient with diabetes can sometimes be a difficult task. Because open wounds are always colonized with microorganisms, most agree that infection should be diagnosed by the presence of systemic or local signs of inflammation. Determining whether or not infection is present in bone can be especially difficult. Diagnosis begins with a history and physical examination in which both classic and 'secondary' findings suggesting invasion of microorganisms or a host response are sought. Serological tests may be helpful, especially measurement of the erythrocyte sedimentation rate in osteomyelitis, but all (including bone biomarkers and procalcitonin) are relatively non-specific. Cultures of properly obtained soft tissue and bone specimens can diagnose and define the causative pathogens in diabetic foot infections. Newer molecular microbial techniques, which may not only identify more organisms but also virulence factors and antibiotic resistance, look very promising. Imaging tests generally begin with plain X-rays; when these are inconclusive or when more detail of bone or soft tissue abnormalities is required, more advanced studies are needed. Among these, magnetic resonance imaging is generally superior to standard radionuclide studies, but newer hybrid imaging techniques (single-photon emission computed tomography/computed tomography, positron emission tomography/computed tomography and positron emission tomography/magnetic resonance imaging) look to be useful techniques, and new radiopharmaceuticals are on the horizon. In some cases, ultrasonography, photographic and thermographic methods may also be diagnostically useful. Improved methods developed and tested over the past decade have clearly increased our accuracy in diagnosing diabetic foot infections.

Diabetic foot infections: state-of-the-art

Foot infections are frequent and potentially devastating complications of diabetes. Unchecked, infection can progress contiguously to involve the deeper soft tissues and ultimately the bone. Foot ulcers in people with diabetes are most often the consequence of one or more of the following: peripheral sensory neuropathy, motor neuropathy and gait disorders, peripheral arterial insufficiency or immunological impairments. Infection develops in over half of foot ulcers and is the factor that most often leads to lower extremity amputation. These amputations are associated with substantial morbidity, reduced quality of life and major financial costs. Most infections can be successfully treated with optimal wound care, antibiotic therapy and surgical procedures. Employing evidence-based guidelines, multidisciplinary teams and institution-specific clinical pathways provides the best approach to guide clinicians through this multifaceted problem. All clinicians regularly seeing people with diabetes should have an understanding of how to prevent, diagnose and treat foot infections, which requires familiarity with the pathophysiology of the problem and the literature supporting currently recommended care.

Osteomyelitis or Charcot neuro-osteoarthropathy? Differentiating these disorders in diabetic patients with a foot problem

Both osteomyelitis and Charcot neuro-osteoarthropathy (CN) are potentially limb-threatening complications of diabetic neuropathy, but they require quite different treatments. Almost all bone infections in the diabetic foot originate from an infected foot ulcer while diabetic osteoarthropathy is a non-infectious process in which peripheral neuropathy plays the critical role. Differentiating between diabetic foot osteomyelitis and CN requires careful evaluation of the patient, including the medical history, physical examination, selected laboratory findings, and imaging studies. Based on available studies, we review the approaches to the diagnostic differentiation of osteomyelitis from CN of the foot in diabetic patients.

Charcot foot and ankle with osteomyelitis

This paper presents a review of the current literature discussing topics of Charcot osteoarthropathy, osteomyelitis, diagnosing osteomyelitis, antibiotic management of osteomyelitis, and treatment strategies for management of Charcot osteoarthropathy with concurrent osteomyelitis.