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.

Feasibility of Multiparametric Perfusion Assessment in Diabetic Foot Ulcer Using Intravoxel Incoherent Motion and Blood Oxygenation-Level Dependent MRI.

BACKGROUND: Patients with type-2 diabetes (T2DM) are at increased risk of developing diabetic foot ulcers (DFU) and experiencing impaired wound healing related to underlying microvascular disease. PURPOSE: To evaluate the sensitivity of intra-voxel incoherent motion (IVIM) and blood oxygen level dependent (BOLD) MRI to microvascular changes in patients with DFUs. STUDY TYPE: Case-control. POPULATION: 20 volunteers who were age and body mass index matched, including T2DM patients with DFUs (N = 10, mean age = 57.5 years), T2DM patients with controlled glycemia and without DFUs (DC, N = 5, mean age = 57.4 years) and healthy controls (HC, N = 5, mean age = 52.8 years). FIELD STRENGTH/SEQUENCE: 3T/multi-b-value IVIM and dynamic BOLD. ASSESSMENT: Resting IVIM parameters were obtained using a multi-b-value diffusion-weighted imaging sequence and two IVIM models were fit to obtain diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f) and microvascular volume fraction (MVF) parameters. Microvascular reactivity was evaluated by inducing an ischemic state in the foot with a blood pressure cuff during dynamic BOLD imaging. Perfusion indices were assessed in two regions of the foot: the medial plantar (MP) and lateral plantar (LP) regions. STATISTICAL TESTS: Effect sizes of group mean differences were assessed using Hedge's g adjusted for small sample sizes. RESULTS: DFU participants exhibited elevated D*, f, and MVF values in both regions (g ≥ 1.10) and increased D (g = 1.07) in the MP region compared to DC participants. DC participants showed reduced f and MVF compared to HC participants in the MP region (g ≥ 1.06). Finally, the DFU group showed reduced tolerance for ischemia in the LP region (g = -1.51) and blunted reperfusion response in both regions (g < -2.32) compared to the DC group during the cuff-occlusion challenge. DATA CONCLUSION: The combined use of IVIM and BOLD MRI shows promise in differentiating perfusion abnormalities in the feet of diabetic patients and suggests hyperperfusion in DFU patients. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 1.

Improved small vessel visibility in diabetic foot arteriography using dual-energy CT.

AIM: To test the feasibility and performance of dual-energy computed tomography (DECT) in foot arteriography of diabetic patients, where contrast medium is largely reduced within the small vessels. MATERIALS AND METHODS: A total of 50 diabetic patients were enrolled prospectively, where DECT was acquired immediately after the CT angiography (CTA, group A) of the lower extremity. Two images were derived from the DECT data, one optimal virtual monochromatic image (VMI, group B) and one fusion image (group C), both of which were compared against the CTA image for visualising the foot arteries. The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were evaluated. The arterial course and contrast were graded each using a five-point scale. The clarity of small vessel depiction was quantified by comparing the number of plantar metatarsal arteries found in the maximum intensity projection image. RESULTS: The median CNRs and SNRs obtained in group B were approximately 45% and 20% higher than those in groups A and C, respectively (p<0.05). Group B also received higher subjective scores on the posterior tibial artery and the foot arteries (all >3) than groups A and C. The number of visible branches of the plantar metatarsal arteries was found to be substantially higher (p<0.05) in group B (median=6) than in groups A (median=2) and C (median=4). CONCLUSION: DECT was found to be superior to conventional CTA in foot arteriography, and beyond the lower extremity, it might be a general favourable solution for imaging regions with small vessels and reduced contrast medium.

Regional skeletal muscle perfusion distribution in diabetic feet may differentiate short-term healed foot ulcers from non-healed ulcers.

OBJECTIVES: The purpose of this study was to leverage a magnetic resonance imaging (MRI) approach to characterize foot perfusion distribution in patients with diabetes, with or without foot ulcers, and determine the ability of the regional perfusion measurements to identify ulcer-healing status. METHODS: Three groups of participants (n = 15 / group) were recruited: controls (without diabetes), type II diabetes, and type II diabetes with foot ulcers. All participants underwent MRI evaluating foot perfusion in three muscle layers (from plantar to dorsal) at rest and during a standardized toe-flexion exercise. The exercise perfusion and perfusion reserve values were analyzed around and away from ulcers. Participants with foot ulcers were followed up 3 months after the MRI exams to determine the foot healing status. RESULTS: Foot plantar muscle perfusion reserves were progressively lower from controls to diabetes, and to diabetes with foot ulcers (e.g., 2.58 ± 0.67, 1.48 ± 0.71, 1.12 ± 0.35, p < 0.001). In controls, the plantar layer had significantly higher perfusion reserve than the dorsal layer, whereas in either diabetes group, there was no significant difference in perfusion reserve among muscle layers. Using the ratio of total exercise perfusion around ulcers to that away from ulcers, the sensitivity and specificity to differentiate healing from non-healed ulcers were 100% and 86%, respectively. CONCLUSIONS: Our study reveals significantly different foot perfusion distribution among controls, diabetes, and diabetes with foot ulcers. The prognostic value of MRI regional perfusion assessments has the potential to monitor interventions to improve ulcer healing outcomes. KEY POINTS: • Contrast-free MRI permits quantitative assessment of regional foot muscle perfusion at rest and during isometric exercise. • Patients with diabetes and foot ulcers, without clinical evidence of peripheral arterial disease, had significantly impaired foot muscle perfusion and perfusion reserve. • Regional foot perfusion distribution may be used to predict the short-term healing status of foot ulcers in diabetes.

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.

The Relationship Between the Global Limb Anatomic Staging System Inframalleolar Modifier and the Outcomes of Diabetic Foot Ulcer with Peripheral Artery Disease.

BACKGROUND: We aimed to investigate the relationship between the condition of the inframalleolar (IM) arteries, as assessed by the Global Limb Anatomic Staging System Inframalleolar (GLASS IM) modifier, and the outcomes of patients with diabetic foot ulcers. METHODS: The data of 215 patients, who underwent endovascular therapy from January 2016 to May 2020 at our center, were retrospectively reviewed. Patients were divided into the P0, P1, and P2 groups according to the angiography results. The rates of ulcer healing, limb salvage, survival, and amputation-free survival were compared during the 2-year period after discharge. RESULTS: Of the 216 affected limbs, 35 (16%) were classed as P0, 122 (57%) as P1, and 59 (27%) as P2. Compared with the P2 group, the P0 + P1 group had a higher ulcer healing rate (P = 0.001), a shorter ulcer healing time (P = 0.004), and a higher survival rate (P = 0.044). GLASS IM Modifier classification P2 was an independent predictor of nonhealing ulcers. No significant difference was observed between the P0 versus P1 groups. CONCLUSIONS: GLASS IM modifier classification P2 is an independent risk factor for a poor outcome. GLASS IM modifier classification P0 versus P1 demonstrates similar outcomes to each other.

Effect of Percutaneous Endovascular Angioplasty Combined with Negative Pressure Drainage on the "One-Stop" Treatment of Ischemic Diabetic Foot Ulcer.

BACKGROUND: To explore the therapeutic effect, safety, and economic benefit of a "one-stop" diagnosis and treatment mode of vascular surgery for ischemic diabetic foot (DF) ulcer and to analyze the associated and independent factors that affect ulcer healing. METHODS: In a prospective, single-center study, patients with ischemic DF ulcers from January 2017 to July 2021 were treated with either percutaneous endovascular angioplasty combined with negative pressure closed drainage (PTA-VSD) or percutaneous endovascular angioplasty combined with depuration (PTA-UD). The effectiveness and economic benefits of the 2 measures were compared, and independent factors affecting ulcer healing were explored via univariate and logistic regression analyses. RESULTS: Fifty patients with ischemic DF ulcer (25 patients in the PTA-VSD group and 25 patients in the PTA-UD group; 40 males and 10 females) were included, with an average age of 67.74 ± 10.71 years. No difference was observed in the demographic data. The findings showed that the ulcer healing time in the PTA-VSD group was significantly shorter than that in the PTA-UD group (154.79 vs. 238.31 days), and the ulcer healing rate at 180 days post surgery was significantly greater in the PTA-VSD group (52% vs. 12%) (P = 0.002, < 0.05). The ulcer score in the PTA-VSD group decreased significantly at 3, 6, and 12 months post surgery. The duration of hospitalization in the PTA-VSD group was greater (P = 0.002, <0.05), but no significant difference in hospitalization frequency and cost was observed between the 2 groups. During follow-up, there was 1 death and 1 amputation in the PTA-UD group, but no death or amputation in the PTA-VSD group. Arterial occlusion was primarily located in the femoral-popliteal artery and the inferior knee artery in the 2 groups, and PTA intervention effectively opened the outflow tract of the affected limb. Two to three outflow tracts were opened in 41 patients. The ankle-brachial index (ABI) after surgery was significantly higher in both groups than before. Univariate and multivariate logistic regression analyses revealed that the Wagner grade and number of outflow channels and therapies (PTA-VSD) could be independent factors affecting ulcer healing. CONCLUSIONS: The severity of DF ulcers is an important factor affecting the quality of life of patients. A multidisciplinary "one-stop" treatment strategy based on percutaneous endovascular angioplasty combined with negative pressure-sealing drainage can rapidly and effectively restore the blood flow to the affected limb and promote ulcer healing without increasing medical costs.

Diabetic Plantar Foot Segmentation in Active Thermography Using a Two-Stage Adaptive Gamma Transform and a Deep Neural Network.

Pathological conditions in diabetic feet cause surface temperature variations, which can be captured quantitatively using infrared thermography. Thermal images captured during recovery of diabetic feet after active cooling may reveal richer information than those from passive thermography, but diseased foot regions may exhibit very small temperature differences compared with the surrounding area, complicating plantar foot segmentation in such cold-stressed active thermography. In this study, we investigate new plantar foot segmentation methods for thermal images obtained via cold-stressed active thermography without the complementary information from color or depth channels. To better deal with the temporal variations in thermal image contrast when planar feet are recovering from cold immersion, we propose an image pre-processing method using a two-stage adaptive gamma transform to alleviate the impact of such contrast variations. To improve upon existing deep neural networks for segmenting planar feet from cold-stressed infrared thermograms, a new deep neural network, the Plantar Foot Segmentation Network (PFSNet), is proposed to better extract foot contours. It combines the fundamental U-shaped network structure, a multi-scale feature extraction module, and a convolutional block attention module with a feature fusion network. The PFSNet, in combination with the two-stage adaptive gamma transform, outperforms multiple existing deep neural networks in plantar foot segmentation for single-channel infrared images from cold-stressed infrared thermography, achieving an accuracy of 97.3% and 95.4% as measured by Intersection over Union (IOU) and Dice Similarity Coefficient (DSC) respectively.

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.

Point-of-care fluorescence imaging reveals extent of bacterial load in diabetic foot ulcers.

Elevated levels of bacteria, including biofilm, increase the risk of chronic wound infection and inhibit healing. Addressing asymptomatic high bacterial loads is challenged by a lack of clinical terminology and diagnostic tools. This post-hoc multicenter clinical trial analysis of 138 diabetic foot ulcers investigates fluorescence (FL)-imaging role in detecting biofilm-encased and planktonic bacteria in wounds at high loads. The sensitivity and specificity of clinical assessment and FL-imaging were compared across bacterial loads of concern (104 -109 CFU/g). Quantitative tissue culture confirmed the total loads. Bacterial presence was confirmed in 131/138 ulcers. Of these, 93.9% had loads >104 CFU/g. In those wounds, symptoms of infection were largely absent and did not correlate with, or increase proportionately with, bacterial loads at any threshold. FL-imaging increased sensitivity for the detection of bacteria across loads 104 -109 (P < .0001), peaking at 92.6% for >108 CFU/g. Imaging further showed that 84.2% of ulcers contained high loads in the periwound region. New terminology, chronic inhibitory bacterial load (CIBL), describes frequently asymptomatic, high bacterial loads in diabetic ulcers and periwound tissues, which require clinical intervention to prevent sequelae of infection. We anticipate this will spark a paradigm shift in assessment and management, enabling earlier intervention along the bacterial-infection continuum and supporting improved wound outcomes.

The efficacy of low-frequency ultrasound as an added treatment for chronic wounds: A meta-analysis.

We performed a meta-analysis to evaluate the effect of low-frequency ultrasound as an added treatment for chronic wounds. A systematic literature search up to May 2022 was performed and 838 subjects with chronic wounds at the baseline of the studies; 412 of them were using the low-frequency ultrasound (225 low-frequency high-intensity contact ultrasound for diabetic foot wound ulcers, and 187 low-frequency low-intensity non-contact ultrasound for a venous leg wound ulcers), and 426 were using standard care (233 sharp debridements for diabetic foot wound ulcers and 193 sham treatments for venous leg wound ulcers). Odds ratio (OR), and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of low-frequency ultrasound as an added treatment for chronic wounds using the dichotomous, and contentious methods with a random or fixed-effect model. The low-frequency high-intensity contact ultrasound for diabetic foot wound ulcers had significantly lower non-healed diabetic foot wound ulcers at ≥3 months (OR, 0.37; 95% CI, 0.24-0.56, P < .001), a higher percentage of diabetic foot wound ulcers area reduction (MD, 17.18; 95% CI, 6.62-27.85, P = .002) compared with sharp debridement for diabetic foot wound ulcers. The low-frequency low-intensity non-contact ultrasound for a venous leg wound ulcers had a significantly lower non-healed venous leg wound ulcers at ≥3 months (OR, 0.31; 95% CI, 0.15-0.62, P = .001), and higher percentage venous leg wound ulcers area reduction (MD, 18.96; 95% CI, 2.36-35.57, P = .03) compared with sham treatments for a venous leg wound ulcers. The low-frequency ultrasound as an added treatment for diabetic foot wound ulcers and venous leg wound ulcers had significantly lower non-healed chronic wound ulcers at ≥3 months, a higher percentage of chronic wound ulcers area reduction compared with standard care. The analysis of outcomes should be with caution because of the low sample size of all the 17 studies in the meta-analysis and a low number of studies in certain comparisons.

[Preliminary Application of Contrast-Enhanced Ultrasound in the Treatment of Diabetic Ulcers].

Objective: To investigate the role of contrast-enhanced ultrasound (CEUS) in the treatment of diabetic ulcers. Methods: The clinical data of 27 diabetic patients, who underwent CEUS examination of their ulcers in our hospital between April 2021 and July 2022 were collected. Among them, 26 patients suffered from diabetic foot ulcers, 5 of whom underwent amputation during hospitalization, and one patient suffered from hip ulcer. The 27 patients' mean age was (64.08±12.57) years. Fasting blood glucose levels of the patients were 3.36-34.61 mmol/L, with a mean of (10.62±8.77) mmol/L. Their glycosylated hemoglobin levels were 5.80%-10.70%, with an average of 7.96%±1.50%. Philips EPIQ7 ultrasound system with L9-3 linear probe of 3-9 MHz was used. First, the patients' ulcers were examined with conventional ultrasound to observe for abnormal echo. Then, 2.4 mL SonoVue (Bracco, Italy), a contrast agent, was injected intravenously through the elbow to look for effusion/pus, sinus tract, or dead space in the lesion area, and images were acquired. Results: Among the 27 patients, except for 5 with amputation stumps, 22 patients had wound areas ranging from 0.16 cm 2 to 215 cm 2, all being accompanied by sinus tract formation. Ten patients underwent ultrasound examination during their treatment. The positive rate of the results of conventional ultrasound was 50% (5/10) for identifying effusion/pus and pseudoaneurysm in the deep area of ulcers, while the positive rate of CEUS results was 100% (10/10). In addition to the lesions found by conventional ultrasound, CEUS also found large sinus tracts or dead spaces in the deep surface of ulcers in 5 additional patients. Of the 27 patients, 17 underwent ultrasound examination of the healing status of sinus tracts and dead spaces in the deep areas of ulcers before discharge. No sinus tracts in the deep areas of the ulcers were found by conventional ultrasound. However, relatively small dead spaces or sinus tracts in the deep areas of the ulcers were found in 10 patients by CEUS. Conventional ultrasound and CEUS found that 1 patient had a small amount of fluid in the amputation stump. In the remaining 6 patients, no deep sinus tracts in the ulcers were found by either conventional ultrasound or CUES, and the ulcers healed completely. Conclusion: By examining microvascular perfusion in diabetic wounds with CEUS, we can observe the extent of sinus tracts during treatment and whether the sinus tracts have healed or whether there are still dead spaces before patient discharge, which provides support for clinical decision-making concerning the treatment of diabetic ulcers.

Presurgical Perspective and Postsurgical Evaluation of the Diabetic Foot.

Management of the diabetic foot is complex and challenging, requiring a multidisciplinary approach. Imaging plays an important role in the decision-making process regarding surgery. This article discusses the presurgical perspective and postsurgical evaluation of the diabetic foot.

Angiosome-Guided Endovascular Revascularization for Treatment of Diabetic Foot Ulcers with Peripheral Artery Disease.

BACKGROUND: Because diabetic foot ulcers (DFUs) are difficult to heal and cause huge economic losses to the society, accelerating their healing has become extremely important. The purpose of this study was to evaluate the effect of revascularization based on the angiosome concept on DFU. METHODS: Between January 2018 and July 2020, 112 consecutive legs with DFUs, in 111 patients who were discharged from the vascular surgery department of our hospital were retrospectively evaluated. The legs were assigned to two groups depending on whether direct arterial flow to the foot ulcer based on the angiosome concept was achieved. Comparisons of the ulcer healing rate, mean time to ulcer healing, major amputation rate, survival rate, and major amputation-free survival rate between the angiosome direct revascularization (DR) and angiosome indirect revascularization (IR) groups were performed. RESULTS: DR was achieved in 71 legs (63%) compared with IR in 41 legs. The ulcer healing rate (70.4% in the DR group versus 34.1% in the IR group, P < 0.01), the mean time to ulcer healing (7.01 ± 4.26 months versus 10.09 ± 3.24 months, P < 0.01), the survival rate (90.1 vs. 53.7%, P < 0.01), and the major amputation-free survival rate (81.7 vs. 48.8%, P < 0.01) were significantly higher in the DR group than in the IR group. Undergoing DR did not significantly reduce the major amputations rate compared to IR (13.4 and 34.1%, respectively, P = 0.15), but there might be a trend. In multivariate models, DR remained a significant predictor for ulcer healing (HR, 7.07; 95% confidence interval (CI), 6.54-7.60, P < 0.01). Opening multiple infrapopliteal arteries in the DR group compared with restoring only one infrapopliteal artery did not significantly improve the ulcer healing rate (P = 0.59), the mean time to ulcer healing (P = 0.70), major amputation rate (P = 0.83), the survival rate (P = 0.31), and the major amputation-free survival rate (P = 0.40). CONCLUSIONS: Attaining a direct arterial flow based on the angiosome concept may be important for ulcer healing, survival, and amputation-free survival in diabetic foot patients. Opening multiple infrapopliteal arteries in DR patients may not improve the ulcer healing, survival, major amputation or amputation-free survival compared with single DR vessel patency.

Influence of pedal arch quality on 5-year survival and limb salvage in patients with diabetic foot ulcers undergoing peripheral angiography.

INTRODUCTION: The aim of this study was to evaluate the influence of pedal arch quality on 5-year survival and limb salvage in diabetic patients with foot wounds undergoing peripheral angiography. METHODS: Between January 2014 and December 2014, 153 diabetic patients with foot wounds underwent peripheral angiography. Final foot angiograms were used to allocate patients according to pedal arch: complete pedal arch (CPA), incomplete pedal arch (IPA), and absent pedal arch (APA). Five-year survival and limb salvage rates were analyzed with Kaplan-Meier curves and compared by means of Gehan-Breslow-Wilcoxon test. Associations of patient and procedure variables with overall survival and limb salvage outcomes were sought with univariate and multivariate analyses. RESULTS: A below-the-knee (BTK) artery was the target vessel in 80 cases (52.3%). Five-year Kaplan-Meier rates of survival were similar in all groups (p = 0.1): CPA 30%, IPA 27.5%, and APA 26.4%. Five-year limb salvage rates were significantly better in patients with CPA/IPA (p < 0.001): CPA 95.1%, IPA 94.3%, and APA 67.3%. In the whole population study, multivariate analysis showed significant association of smoking (p = 0.01), chronic renal failure (p = 0.02), and severity of foot wounds (p < 0.001) with survival. Coronary artery disease (p = 0.03), severity of foot wounds (p = 0.001), and pedal arch status (p = 0.05) showed strong association with limb salvage. CONCLUSIONS: Pedal arch quality significantly affected limb salvage but not survival at 5 years in patients with diabetic foot ulcers. Smoking, chronic renal failure, and severity of foot wounds affected overall survival, whilst coronary artery disease, and severity of foot wounds limb salvage.

Ultrasonographic features of diabetic foot osteomyelitis: a case series.

OBJECTIVE: Osteomyelitis is a limb-threatening complication of diabetic foot ulcers. Early identification of the disease is key to ensuring successful prognosis. In this study, we describe ultrasonographic features for the identification of osteomyelitis. METHOD: Patients were screened through clinical, ultrasonographic and probe-to-bone tests. RESULTS: Ultrasonographic features in three patients that could be used to identify diabetic foot osteomyelitis included periosteal reaction, periosteal elevation, cortical erosions and presence of sequestrum, all of which were confirmed by a plain X-ray. CONCLUSION: An ultrasonographic examination could be used for the early detection of osteomyelitis, which could help clinicians devise prompt treatment strategies.

Thermal Change Index-Based Diabetic Foot Thermogram Image Classification Using Machine Learning Techniques.

Diabetes mellitus (DM) can lead to plantar ulcers, amputation and death. Plantar foot thermogram images acquired using an infrared camera have been shown to detect changes in temperature distribution associated with a higher risk of foot ulceration. Machine learning approaches applied to such infrared images may have utility in the early diagnosis of diabetic foot complications. In this work, a publicly available dataset was categorized into different classes, which were corroborated by domain experts, based on a temperature distribution parameter-the thermal change index (TCI). We then explored different machine-learning approaches for classifying thermograms of the TCI-labeled dataset. Classical machine learning algorithms with feature engineering and the convolutional neural network (CNN) with image enhancement techniques were extensively investigated to identify the best performing network for classifying thermograms. The multilayer perceptron (MLP) classifier along with the features extracted from thermogram images showed an accuracy of 90.1% in multi-class classification, which outperformed the literature-reported performance metrics on this dataset.

A Novel Machine Learning Approach for Severity Classification of Diabetic Foot Complications Using Thermogram Images.

Diabetes mellitus (DM) is one of the most prevalent diseases in the world, and is correlated to a high index of mortality. One of its major complications is diabetic foot, leading to plantar ulcers, amputation, and death. Several studies report that a thermogram helps to detect changes in the plantar temperature of the foot, which may lead to a higher risk of ulceration. However, in diabetic patients, the distribution of plantar temperature does not follow a standard pattern, thereby making it difficult to quantify the changes. The abnormal temperature distribution in infrared (IR) foot thermogram images can be used for the early detection of diabetic foot before ulceration to avoid complications. There is no machine learning-based technique reported in the literature to classify these thermograms based on the severity of diabetic foot complications. This paper uses an available labeled diabetic thermogram dataset and uses the k-mean clustering technique to cluster the severity risk of diabetic foot ulcers using an unsupervised approach. Using the plantar foot temperature, the new clustered dataset is verified by expert medical doctors in terms of risk for the development of foot ulcers. The newly labeled dataset is then investigated in terms of robustness to be classified by any machine learning network. Classical machine learning algorithms with feature engineering and a convolutional neural network (CNN) with image-enhancement techniques are investigated to provide the best-performing network in classifying thermograms based on severity. It is found that the popular VGG 19 CNN model shows an accuracy, precision, sensitivity, F1-score, and specificity of 95.08%, 95.08%, 95.09%, 95.08%, and 97.2%, respectively, in the stratification of severity. A stacking classifier is proposed using extracted features of the thermogram, which is created using the trained gradient boost classifier, XGBoost classifier, and random forest classifier. This provides a comparable performance of 94.47%, 94.45%, 94.47%, 94.43%, and 93.25% for accuracy, precision, sensitivity, F1-score, and specificity, respectively.

Segmentation of Plantar Foot Thermal Images Using Prior Information.

Diabetic foot (DF) complications are associated with temperature variations. The occurrence of DF ulceration could be reduced by using a contactless thermal camera. The aim of our study is to provide a decision support tool for the prevention of DF ulcers. Thus, the segmentation of the plantar foot in thermal images is a challenging step for a non-constraining acquisition protocol. This paper presents a new segmentation method for plantar foot thermal images. This method is designed to include five pieces of prior information regarding the aforementioned images. First, a new energy term is added to the snake of Kass et al. in order to force its curvature to match that of the prior shape, which has a known form. Second, we defined the initial contour as the downsized prior-shape contour, which is placed inside the plantar foot surface in a vertical orientation. This choice makes the snake avoid strong false boundaries present outside the plantar region when evolving. As a result, the snake produces a smooth contour that rapidly converges to the true boundaries of the foot. The proposed method is compared to two classical prior-shape snake methods, that of Ahmed et al. and that of Chen et al. A database of 50 plantar foot thermal images was processed. The results show that the proposed method outperforms the previous two methods with a root-mean-square error of 5.12 pixels and a dice similarity coefficient of 94%. The segmentation of the plantar foot regions in the thermal images helped us to assess the point-to-point temperature differences between the two feet in order to detect hyperthermia regions. The presence of such regions is the pre-sign of ulcers in the diabetic foot. Furthermore, our method was applied to hyperthermia detection to illustrate the promising potential of thermography in the case of the diabetic foot. Associated with a friendly acquisition protocol, the proposed segmentation method is the first step for a future mobile smartphone-based plantar foot thermal analysis for diabetic foot patients.