Diabetic foot ulcers segmentation challenge report: Benchmark and analysis

Monitoring the healing progress of diabetic foot ulcers is a challenging process. Accurate segmentation of foot ulcers can help podiatrists to quantitatively measure the size of wound regions to assist prediction of healing status. The main challenge in this field is the lack of publicly available manual delineation, which can be time consuming and laborious. Recently, methods based on deep learning have shown excellent results in automatic segmentation of medical images, however, they require large-scale datasets for training, and there is limited consensus on which methods perform the best. The 2022 Diabetic Foot Ulcers segmentation challenge was held in conjunction with the 2022 International Conference on Medical Image Computing and Computer Assisted Intervention, which sought to address these issues and stimulate progress in this research domain. A training set of 2000 images exhibiting diabetic foot ulcers was released with corresponding segmentation ground truth masks. Of the 72 (approved) requests from 47 countries, 26 teams used this data to develop fully automated systems to predict the true segmentation masks on a test set of 2000 images, with the corresponding ground truth segmentation masks kept private. Predictions from participating teams were scored and ranked according to their average Dice similarity coefficient of the ground truth masks and prediction masks. The winning team achieved a Dice of 0.7287 for diabetic foot ulcer segmentation. This challenge has now entered a live leaderboard stage where it serves as a challenging benchmark for diabetic foot ulcer segmentation.

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.

The usefulness of quantitative 99mTc-HMPAO WBC SPECT/CT for predicting lower extremity amputation in diabetic foot infection

We investigated the usefulness of quantitative 99mTc-white blood cell (WBC) single photon emission computed tomography (SPECT)/computed tomography (CT) for predicting lower extremity amputation in diabetic foot infection (DFI). A total of 93 feet of 83 consecutive patients with DFI who underwent WBC SPECT/CT for treatment planning were retrospectively analysed. The clinical and SPECT/CT parameters were collected along with the measurements of the maximum standardized uptake value (SUVmax) at DFI. Statistical logistic regression analysis was performed to explore the predictors of LEA and receiver operating characteristic (ROC) curve was analysed to assess the predictive value of SPECT/CT. The independent predictors of amputation were previous amputation (OR 11.9), numbers of SPECT/CT lesions (OR 2.1), and SUVmax of DFI; either continuous SUVmax (1-increase) (OR 1.3) or categorical SUVmax > 1.1 (OR 21.6). However, the conventional SPECT/CT interpretation failed to predict amputation. In ROC analysis, the SUVmax yielded a fair predictor (area under the curve (AUC) 0.782) of amputation. The model developed from these independent predictors yielded an excellent performance for predicting amputation (AUC 0.873). Quantitative WBC SPECT/CT can provide new information useful for predicting the outcomes and guiding treatment for patients with DFI.

Diagnostic Performance of Ultrasonography for Diabetic Foot Osteomyelitis

Objective: This study aims to analyze the potential diagnostic capability of ultrasonography (US) in detecting diabetic foot osteomyelitis (DFO) in patients with diabetic foot ulcers (DFUs). Approach: A 1-year prospective study was conducted on 47 consecutive patients with active DFUs and suspicion of DFO at a specialized diabetic foot unit. The following ultrasonographic features were evaluated at baseline: (1) periosteal reaction; (2) periosteal elevation; (3) cortical disruption; (4) sequestrum; and (5) positive power Doppler. The primary outcome measure aimed to establish the effectiveness of ultrasonographic features compared with aseptic bone culture for diagnosing DFO. Receiver operating characteristic (ROC) curves were utilized to evaluate the diagnostic performance of ultrasonographic features. Sample size could not be determined as it is the first study to assess ultrasonographic features for the diagnosis of DFO. The research adhered to the guidelines for diagnostic accuracy studies (Standards for Reporting of Diagnostic Accuracy Studies [STARD] 2015). Results: All patients (n = 24) diagnosed with DFO exhibited positive power Doppler, resulting in a sensitivity (S) and specificity (SP) of 1 and an area under the curve (AUC) of 1 (p < 0.001 [1-1]). Cortical disruption was present in 23 patients (95.8%) with DFO, yielding an S of 0.93, SP of 1, and AUC of 0.96 (p < 0.001 [0.88-1]). Innovation: It validates the diagnostic value of US for DFO as it is the first and largest study of its kind to establish a clear reference standard to guide clinician decision-making. Conclusion: This study demonstrates the effectiveness of cortical disruption and positive power Doppler in assessing DFO through US.

Image Smart Segmentation Analysis Against Diabetic Foot Ulcer Using Internet of Things with Virtual Sensing

Diabetic foot ulcer (DFU) is a problem worldwide, and prevention is crucial. The image segmentation analysis of DFU identification plays a significant role. This will produce different segmentation of the same idea, incomplete, imprecise, and other problems. To address these issues, a method of image segmentation analysis of DFU through internet of things with the technique of virtual sensing for semantically similar objects, the analysis of four levels of range segmentation (region-based, edge-based, image-based, and computer-aided design-based range segmentation) for deeper segmentation of images is implemented. In this study, the multimodal is compressed with the object co-segmentation for semantical segmentation. The result is predicting the better validity and reliability assessment. The experimental results demonstrate that the proposed model can efficiently perform segmentation analysis, with a lower error rate, than the existing methodologies. The findings on the multiple-image dataset show that DFU obtains an average segmentation score of 90.85% and 89.03% correspondingly in two types of labeled ratios before DFU with virtual sensing and after DFU without virtual sensing (i.e., 25% and 30%), which is an increase of 10.91% and 12.22% over the previous best results. In live DFU studies, our proposed system improved by 59.1% compared with existing deep segmentation-based techniques and its average image smart segmentation improvements over its contemporaries are 15.06%, 23.94%, and 45.41%, respectively. Proposed range-based segmentation achieves interobserver reliability by 73.9% on the positive test namely likelihood ratio test set with only a 0.25 million parameters at the pace of labeled data.

The role of diabetic foot treatment in improving left ventricular function: Insights from global longitudinal strain echocardiography

We decided to evaluate the effect of treatment of diabetic foot ulcers in improving heart function by strain echocardiography than conventional transthoracic echocardiography. This prospective cross-sectional study included patients with diabetic foot ulcer (DFU). Conventional and two-dimensional strain echocardiography performed before and after three months diabetic foot treatment. Then, we compared the echocardiographic parameters including left ventricular ejection fraction (LV-EF), left ventricular global longitudinal strain (LV-GLS). Multivariate and univariate logistic regression analysis were performed to find which variable was mainly associated with LV-GLS changes. 62 patients with DFU were conducted. After echocardiography, all patients underwent surgical or non-surgical treatments. Three months after the treatment, LV-EF was not significantly different with its' primary values (P = 0.250), but LV-GLS became significantly different (P<0.05). In the multivariate logistic regression analysis, with the increase in the grade of ulcer, LV-GLS improved by 6.3 times. Not only the treatment of DFU helps to control adverse outcomes like infection, limb loss and morbidity but also it enhances cardiac function. Of note, strain echocardiography found to be a better indicator of myocardial dysfunction than LV-EF. These findings make a strong reason for the routine assessment of cardiac function in patients with DFU.

Amide proton transfer weighted contrast has diagnostic capacity in detecting diabetic foot: an MRI-based case-control study

Objective

To evaluate the role of foot muscle amide proton transfer weighted (APTw) contrast and tissue rest perfusion in quantifying diabetic foot (DF) infection and its correlation with blood parameters.

Materials and methods

With approval from an ethical review board, this study included 40 diabetes mellitus (DM) patients with DF and 31 DM patients without DF or other lower extremity arterial disease. All subjects underwent MRI, which included foot sagittal APTw and coronal arterial spin labeling (ASL) imaging. The normalized MTRasym (3.5 ppm) and the ratio of blood flow (rBF) in rest status of the affected side lesions to the non-affected contralateral side were determined. The inter-group differences of these variables were evaluated. Furthermore, the association between normalized MTRasym (3.5 ppm), rBF, and blood parameters [fasting blood glucose (FBG), glycosylated hemoglobin content, C-reactive protein, neutrophil percentage, and white blood cell count] was explored. Using an ROC curve, the diagnostic capacity of normalized MTRasym (3.5 ppm), BF, and blood biochemical markers in differentiating with or without DF in DM was assessed.

Results

In the DF group, MTRasym (3.5 ppm) and BF in lesion and normalized MTRasym (3.5 ppm) were higher than those in the control group (p < 0.05). In addition, correlations were identified between normalized MTRasym (3.5 ppm) and blood parameters, such as C-reactive protein, glycosylated hemoglobin content, FBG, neutrophil ratio, and white blood cell (p < 0.001). Meanwhile, association between BF in lesion and blood parameters, such as C-reactive protein, neutrophil percentage, and FBG (p < 0.01). AUC of normalized MTRasym (3.5 ppm) in identifying with/without DF in patients with DM is 0.986 (95% CI, 0.918-1.00) with the sensitivity of 97.22% and the specificity of 100%.

Conclusion

Normalized MTRasym (3.5 ppm) and the BF in lesion may be treated as a safer and more convenient new indicator to evaluate the tissue infection without using a contrast agent, which may be useful in monitoring and preoperatively assessing DF patients with renal insufficiency.

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.

A Clinical Study to Evaluate Autofluorescence Imaging of Diabetic Foot Ulcers Using a Novel Artificial Intelligence Enabled Noninvasive Device

Diabetic foot ulcers, with worldwide prevalence ranging from 12%-25%, are an important cause of nontraumatic lower limb amputation. Evidence-based assessment of early infection can help the clinician provide the right first line treatment thus helping improve the wound closure rate. Illuminate®, a novel point of care device working on multispectral autofluorescence imaging, helps in the rapid identification and classification of bacteria. This study was aimed to evaluate the diagnostic accuracy of the device in detecting bacterial gram type against standard culture methods. A total of 178 patients from a tertiary care center for diabetes was recruited and 203 tissue samples were obtained from the wound base by the plastic surgeon. The device was handled by the trained investigator to take wound images. The tissue samples were taken from the color-coded infected region as indicated by the device's Artificial Intelligence algorithm and sent for microbial assessment. The results were compared against the Gram type inferred by the device and the device was found to have an accuracy of 89.54%, a positive predictive value of 86.27% for detecting Gram-positive bacteria, 80.77% for Gram-negative bacteria, and 91.67% for no infection. The negative predictive value corresponded to 87.25% for Gram-positive, 92% for Gram-negative, and 96.12% for no infection. The Results exhibited the accuracy of this novel autofluorescence device in identifying and classifying the gram type of bacteria and its potential in significantly aiding clinicians towards early infection assessment and treatment.

Sub-calcaneal plantar fat pad assessment using dual-energy computed tomography: First experience in the diabetic foot

BACKGROUND

This study assessed the use of dual-energy computed tomography (CT) to evaluate sub-calcaneal plantar fat pad changes in people with diabetic neuropathy.

METHODS

Dual-energy CT scans of people with diabetic neuropathy and non-diabetic controls were retrospectively included. Average CT values (in Hounsfield Units) and thickness (in centimeters) of the sub-calcaneal plantar fat pad were measured in mono-energetic images at two energy levels (40 keV and 70 keV). The CT values measured in patients with diabetic neuropathy were correlated to barefoot plantar pressure measurements performed during walking in a clinical setting.

FINDINGS

Forty-five dual-energy CT scans of people with diabetic neuropathy and eleven DECT scans of non-diabetic controls were included. Mean sub-calcaneal plantar fat pad thickness did not significantly differ between groups (diabetes group 1.20 ± 0.34 cm vs. control group 1.21 ± 0.28 cm, P = 0.585). CT values at both 40 keV (-34.7 ± 48.7 HU vs. -76.0 ± 42.8 HU, P = 0.013) and 70 keV (-11.2 ± 30.8 HU vs. -36.3 ± 27.2 HU, P = 0.017) were significantly higher in the diabetes group compared to controls, thus contained less fatty tissue. This elevation was most apparent in patients with Type 1 diabetes. CT values positively correlated with the mean peak plantar pressure.

INTERPRETATION

Dual-energy CT was able to detect changes in the plantar fat pad of people with diabetic neuropathy.

Diabetic Foot Ulcer Imaging: An Overview and Future Directions

Diabetic foot ulcers (DFUs) affect one in every three people with diabetes. Imaging plays a vital role in objectively complementing the gold-standard visual yet subjective clinical assessments of DFUs during the wound treatment process. Herein, an overview of the various imaging techniques used to image DFUs is summarized. Conventional imaging modalities (e.g., computed tomography, magnetic resonance imaging, positron emission tomography, single-photon emitted computed tomography, and ultrasound) are used to diagnose infections, impact on the bones, foot deformities, and blood flow in patients with DFUs. Transcutaneous oximetry is a gold standard to assess perfusion in DFU cases with vascular issues. For a wound to heal, an adequate oxygen supply is needed to facilitate reparative processes. Several optical imaging modalities can assess tissue oxygenation changes in and around the wounds apart from perfusion measurements. These include hyperspectral imaging, multispectral imaging, diffuse reflectance spectroscopy, near-infrared (NIR) spectroscopy, laser Doppler flowmetry or imaging, and spatial frequency domain imaging. While perfusion measurements are dynamically monitored at point locations, tissue oxygenation measurements are static two-dimensional spatial maps. Recently, we developed a spatio-temporal NIR-based tissue oxygenation imaging approach to map for the extent of asynchrony in the oxygenation flow patterns in and around DFUs. Researchers also measure other parameters such as thermal maps, bacterial infections (from fluorescence maps), pH, collagen, and trans-epidermal water loss to assess DFUs. A future direction for DFU imaging would ideally be a low-cost, portable, multi-modal imaging platform that can provide a visual and physiological assessment of wounds for comprehensive wound care intervention and management.

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.

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.

Grading Fractures on Foot and Ankle X-rays and MRI Scans in the Active Charcot Foot in Diabetes: How Strong Is the Agreement Between Modalities?

OBJECTIVE

To compare X-ray and MRI as diagnostic tests of active Charcot neuro-osteoarthropathy (CNO) in diabetes.

RESEARCH DESIGN AND METHODS

X-rays and MRI scans of 48 participants were rated for severity of fracture (0 = no fracture, 1 = fracture, 2 = collapse/fragmentation), and for absence/presence of bone marrow edema (BME) on MRI and absence/presence of bone injury on X-ray. The agreement between modalities was assessed with tests for symmetry, marginal homogeneity, and κ-coefficients.

RESULTS

X-ray underscored MRI in grading fractures in the metatarsals (P = 0.05) and tarsals (P < 0.001) and reported as normal 79% of the bones with BME. The agreement between X-ray and MRI for grading severity of fracture was moderate to substantial (κ = 0.53; P < 0.001) and for detecting bone injury, slight to fair (κ = 0.17; P < 0.001).

CONCLUSIONS

The significant underperformance of X-ray in the assessment of the hot, swollen foot in diabetes should be considered when confirming or refuting the diagnosis of active CNO.

A fluoroscopic imaging-guided computational analyses to inform internal tissue loads within fat pad of the diabetic foot during gait

To accurately predict internal tissue loads for early diagnostics of diabetic foot ulcerations, a novel data-driven computational analysis was conducted. A dedicated dual fluoroscopic system was combined with a pressure mat to simultaneously characterize foot motions and soft tissue's material properties during gait. Finite element (FE) models of the heel pad of a diabetic patient were constructed with 3D trajectories of the calcaneus applied as boundary conditions to simulate gait events. The tensile and compressive stresses occurring in the plantar tissue were computed. Predictions of the layered tissue FE model with anatomically-accurate heel pad structures (i.e., fat and skin) were compared with those of the traditional lumped tissue (i.e., homogeneous) models. The influence of different material properties (patient-specific versus generic) on internal tissue stresses was also investigated. The results showed the peak tensile stresses in the layered tissue model were predominantly found in the skin and distributed towards the circumferential regions of the heel, while peak compressive stresses in the fat tissue-bone interface were up to 51.4% lower than those seen in the lumped models. Performing FE analyses at four different phases of walking revealed that ignorance of layered tissue structures resulted in an unphysiological increase of peak-to-peak value of stress fluctuation in the fat and skin tissue components. Thus, to produce more clinical-relevant predictions, foot FE models are suggested to include layered tissue structures of the plantar tissue for an improved estimation of internal stresses in the diabetic foot in gait.

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.

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.

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.

FusionSegNet: Fusing global foot features and local wound features to diagnose diabetic foot

The Diabetic Foot (DF) is threatening every diabetic patient's health. Every year, more than one million people suffer amputation in the world due to lack of timely diagnosis of DF. Diagnosing DF at early stage is very essential to improve the survival rate and quality of patients. However, it is easy for inexperienced doctors to confuse DFU wounds and other specific ulcer wounds when there is a lack of patients' health records in underdeveloped areas. It is of great value to distinguish diabetic foot ulcer from chronic wounds. And the characteristics of deep learning can be well applied in this field. In this paper, we propose the FusionSegNet fusing global foot features and local wound features to identify DF images from foot ulcer images. In particular, we apply a wound segmentation module to segment foot ulcer wounds, which guides the network to pay attention to wound area. T he FusionSegNet combines two kinds of features to make a final prediction. Our method is evaluated upon our dataset collected by Shanghai Municipal Eighth People's Hospital in clinical environment. In the training-validation stage, we collect 1211 images for a 5-fold cross-validation. Our method can classify DF images and non-DF images with the area under the receiver operating characteristic curve (AUC) value of 98.93%, accuracy of 95.78%, sensitivity of 94.27%, specificity of 96.88%, and F1-score of 94.91%. With the excellent performance, the proposed method can accurately extract wound features and greatly improve the classification performance. In general, the method proposed in this paper can help clinicians make more accurate judgments of diabetic foot and has great potential in clinical auxiliary diagnosis.

[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.

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.

A new precise way to guide the debridement process of diabetic foot ulcer using indocyanine green fluorescence molecular imaging

OBJECTIVE

The purpose of this study was to estimate the value of a novel imaging technique in necrotic tissue debridement of diabetic foot ulcers (DFU), using near-infrared (NIR) fluorescence molecular imaging (FMI) of indocyanine green (ICG).

METHODS

The patients with DFU were included and divided into a FMI navigation debridement group and a traditional group. The FMI of the wounds and the debridement effect of each group was analyzed, including debridement frequency, length of hospital stay, and the histological examination of removed tissue.

RESULT

A total of 40 patients with DFU (23 cases in the FMI group and 17 cases in the traditional group) were included in this study. The positive rate of wound fluorescence in the FMI group was 96%, and no patients had related side effects. The pathological examination confirmed that the tissue emitting NIR fluorescence was totally necrotic tissue. In addition, the debridement frequency in the FMI group is less than that in the traditional group, but there is no difference in the length of hospital stay between the two groups.

CONCLUSION

ICG FMI technique can accurately illuminated necrotic tissue, with high sensitivity, easy operation and good safety, which would be a new way to precisly guide the process of debridement in the clinic.

ACR Appropriateness Criteria® Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection (Excluding Spine and Diabetic Foot): 2022 Update

Musculoskeletal infections involve bones, joints, and soft tissues. These infections are a common clinical scenario in both outpatient and emergent settings. Although radiography provides baseline findings, a multimodality approach is often implemented to provide more detailed information on the extent of infection involvement and complications. MRI with intravenous contrast is excellent for the evaluation of musculoskeletal infections and is the most sensitive for diagnosing osteomyelitis. MRI, CT, and ultrasound can be useful for joint and soft tissue infections. When MRI or CT is contraindicated, bone scans and the appropriate utilization of other nuclear medicine scans can be implemented for aiding in the diagnostic imaging of infection, especially with metal hardware and arthroplasty artifacts on MRI and CT. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The Use of Point-of-Care Bacterial Autofluorescence Imaging in the Management of Diabetic Foot Ulcers: A Pilot Randomized Controlled Trial

OBJECTIVE

To estimate comparative healing rates and decision-making associated with the use of bacterial autofluorescence imaging in the management of diabetic foot ulcers (DFUs).

RESEARCH DESIGN AND METHODS

This is a single-center (multidisciplinary outpatient clinic), prospective pilot, randomized controlled trial (RCT) in patients with an active DFU and no suspected clinical infection. Consenting patients were randomly assigned 1:1 to either treatment as usual informed by autofluorescence imaging (intervention), or treatment as usual alone (control). The primary outcome was the proportion of ulcers healed at 12 weeks by blinded assessment. Secondary outcomes included wound area reduction at 4 and 12 weeks, patient quality of life, and change in management decisions after autofluorescence imaging.

RESULTS

Between November 2017 and November 2019, 56 patients were randomly assigned to the control or intervention group. The proportion of ulcers healed at 12 weeks in the autofluorescence arm was 45% (n = 13 of 29) vs. 22% (n = 6 of 27) in the control arm. Wound area reduction was 40.4% (autofluorescence) vs. 38.6% (control) at 4 weeks and 91.3% (autofluorescence) vs. 72.8% (control) at 12 weeks. Wound debridement was the most common intervention in wounds with positive autofluorescence imaging. There was a stepwise trend in healing favoring those with negative autofluorescence imaging, followed by those with positive autofluorescence who had intervention, and finally those with positive autofluorescence with no intervention.

CONCLUSIONS

In the first RCT, to our knowledge, assessing the use of autofluorescence imaging in DFU management, our results suggest that a powered RCT is feasible and justified. Autofluorescence may be valuable in addition to standard care in the management of DFU.

Automatic Wound Type Classification with Convolutional Neural Networks

Chronic wounds are ulcerations of the skin that fail to heal because of an underlying condition such as diabetes mellitus or venous insufficiency. The timely identification of this condition is crucial for healing. However, this identification requires expert knowledge unavailable in some care situations. Here, artificial intelligence technology may support clinicians. In this study, we explore the performance of a deep convolutional neural network to classify diabetic foot and venous leg ulcers using wound images. We trained a convolutional neural network on 863 cropped wound images. Using a hold-out test set with 80 images, the model yielded an F1-score of 0.85 on the cropped and 0.70 on the full images. This study shows promising results. However, the model must be extended in terms of wound images and wound types for application in clinical practice.

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.

[Does inflammatory activity of Charcot foot affect successful corrective arthrodesis?]

BACKGROUND

Neuro-osteoarthropathy of the foot (CN) is divided into an active and inactive stage, with impact on the further treatment. The histopathological Charcot score (HCS) can be used, to grade the inflammatory activity in tissue samples.

RESEARCH QUESTION

This study aims to clarify whether successful bony healing after arthrodesis is related to inflammatory activity of the disease.

MATERIAL AND METHOD

N = 80 patients underwent corrective arthrodesis of the midfoot (group 1) or hindfoot/ankle (group 2). A distinction was made between patients with/without diabetes mellitus and with/without pain perception. Intraoperative samples were taken to determine HCS. The osseous healing of the arthrodesis was determined by computed tomography 12 weeks postoperatively.

RESULTS

There was an indirect correlation between bony consolidation and HCS. In group 2, there was a significantly worse bony healing in patients without pain sensation. There seems to be a tendency for HCS to be increased in patients without diabetes/no pain sensation.

DISCUSSION

The present study confirms the assumption that corrective arthrodesis should be performed in the inactive stage of CN only. High activity levels obviously impede bony healing. HCS represents a relevant prognostic tool for surgical treatment.

Diabetes Status is Associated With Plantar Soft Tissue Stiffness Measured Using Ultrasound Reverberant Shear Wave Elastography Approach

INTRODUCTION

The purpose of this study was to investigate the association between the mechanical properties of plantar soft tissue and diabetes status.

METHOD

51 (M/F: 21/30) participants with prediabetes onset (fasting blood sugar [FBS] level > 100 mg/dL), age >18 years, and no lower limb amputation were recruited after ethical approval was granted from Pontificia Universidad Catolica del Peru ethical review board. Ultrasound reverberant shear wave elastography was used to assess the soft tissue stiffness at the 1st metatarsal head (MTH), 3rd MTH, and the heel at both feet.

RESULTS

Spearman's rank-order correlation (rho) test indicated a significant (P < .05) positive correlations between FBS level and the plantar soft tissue shear wave speed at the 1st MTH: rho = 0.402 (@400 Hz), rho = 0.373 (@450 Hz), rho = 0.474 (@500 Hz), rho= 0.395 (@550 Hz), and rho = 0.326 (@600 Hz) in the left foot and rho = 0.364 (@450 Hz) in the right foot. Mann-Whitney U test indicated a significantly (P < .05) higher shear wave speed in the plantar soft tissue with the following effect sizes (r) at the 1st MTH of the left foot at all tested frequencies: r = 0.297 (@450 Hz), r = 0.345 (@500 Hz), r = 0.322 (@550 Hz), and r = 0.275 (@600 Hz), and at the 1st MTH of right foot r = 0.286 (@400 Hz) in diabetes as compared with the age and body mass index matched prediabetes group.

CONCLUSION

An association between fasting blood sugar level and the stiffness of the plantar soft tissue with higher values of shear wave speed in diabetes versus prediabetes group was observed. This indicated that the proposed approach can improve the assessment of the severity of diabetic foot complications with potential implications in patient stratification.

Evaluation of Achilles Tendon in Patients with Diabetic Foot Ulcer by High-Frequency Ultrasound Combined with Real-Time Shear-Wave Elastography

To our best knowledge, no study investigated the utility of the combination of high-frequency US and real-time shear wave elastography (RTSWE) in the evaluation of Achilles tendon (AT). Our study aimed to evaluate AT in patients with diabetic foot ulcers using high-frequency US and RTSWE. We retrospectively reviewed 100 patients who visited our hospital due to diabetes. Patients were divided into the study group (those with diabetic foot ulcers) and the control group (those without diabetic foot ulcers). Patients' demographics, basic medical records, and laboratory tests were reviewed. High-frequency ultrasound and RTSWE were performed in both AT for all 100 patients. Young's modulus was measured at the upper, middle, and lower parts of each AT by RTSWE. There were 50 patients with diabetic foot ulcers. Patients in the study group had older age, a higher incidence of insulin use, and a higher level of cholesterol than those in the control group. However, thickness and Young's modulus of AT were comparable in two groups, when evaluated by the combination of high-frequency ultrasound and RTSWE. There was no significant difference in thickness and elastic modulus of AT in patients with and without diabetic foot ulcers when evaluated by the combination of high-frequency ultrasound and RTSWE.

The evaluation of podiatrists, with knowledge and training in diagnostic musculoskeletal ultrasound, to describe sonographic images of diabetic foot wounds in the United Kingdom and Australia

AIMS

Currently, wound management decisions are based largely on visual observations such as photographs, descriptors or measurements which can lack detail and do not always capture the sub-wound area. A previous case series suggests that there is benefit in using ultrasound imaging (USI) to evaluate diabetic foot ulcers (DFU) at point-of-care, however no guidance exists to inform its use. This scoping exercise explores the capacity of podiatrists with experience in interpreting musculoskeletal structures using USI to interpret sonographic images of DFU.

METHODS

Following a short briefing session, podiatrists with previous musculoskeletal (MSK) USI training were asked to review and report on previously recorded static sonographic images (n = 8) of active DFU. Content analysis was utilised to identify recurring keywords within the podiatrists' reports which were coded and assigned to categories to gain context to the data.

RESULTS

Seven podiatrists participated in the study. Four categories were constructed for the purposes of analysis: 1) Frequency of reporting, 2) Language used in reporting, 3) Observations, 4) Clinical impression Frequently, the reported findings between podiatrists were found to be similar, especially those related to bone morphology. However greater variability was seen in the reporting of wound specific soft-tissue observations.

CONCLUSION

This scoping exercise has shown that podiatrists can translate their existing USI skills to make rudimentary reports on clinical findings in DFU. All participants were consistently able to identify and describe characteristics associated with DFU from a single b mode static wound ultrasound image. Findings from this investigation can be used as a foundation for further work to establish accuracy and reliability to validate DFU sonography. In conjunction the development of protocols and training materials will enable the adoption of USI to assess DFU in clinical practice. This will in turn, contribute to improved patient care and establish a new paradigm for wound surveillance which is translatable to other wound types.

The Role of 99mTc-antigranulocyte SPECT/CT In Community-Acquired Diabetic Foot Osteomyelitis: A Clinical Experience

BACKGROUND

Magnetic resonance imaging (MRI) is the actual gold standard for the radiological diagnosis of diabetic foot osteomyelitis (DFO).

MATERIALS AND METHODS

MRI is not always available and many patients have contraindications. We evaluated the clinical value of 99mTc-antigranulocyte SPECT/CT (AGS) in eight DFO patients who underwent MRI before.

RESULTS

The goal was to have a better clinical view on the extent of bone infection and to ameliorate the surgical approach for DFO. However, this additional scintigraphy did not change anything in the clinical approach.

CONCLUSION

We shared our experience with AGS for clinical management of complex DFO cases.

Case report: Successful treatment of human diabetic foot ulcer using low-intensity diagnostic ultrasound combined with microbubbles: Two cases

BACKGROUND

Diabetic foot ulcer (DFU) is one of the serious complications of diabetes, which has high disability rate and mortality. Low-intensity ultrasound combined with microbubbles in blood circulation can enhance the blood perfusion effect of local soft tissue, which has the potential to promote the healing of diabetic ulcer. Here, we report how this method was used to help the healing of two patients with chronic refractory DFUs.

CASE PRESENTATION

In case 1, a 56-year-old man with 3-years history of type 2 diabetes had a 3.0×2.0 cm ulcer which infected with staphylococcus aureus on his right calf for more than half a month. In case 2, a 70-year-old man with 10-years history of type 2 diabetes presented with an 8-month right heel ulcer that developed to 7.5×4.6 cm. And he also had hyperlipidemia, hypertension, and renal impairment. Both patients were enrolled in our study to receive treatment of low-intensity diagnostic ultrasound (LIDUS) combined with microbubbles. They were discharged after a 20-minute daily standard treatment for 7 consecutive days. The ulcers in both cases completely healed in 60 days and 150 days, respectively, and haven't recurred for more than one year of follow-up.

CONCLUSION

It is feasible, safe, and effective to use commercial LIDUS combined with commercial microbubbles in the treatment of diabetic lower extremity ulcers. This study may provide an innovative and non-invasive method for the treatment of DFUs.

Wound Size Imaging: Ready for Smart Assessment and Monitoring

Significance: We introduce and evaluate emerging devices and modalities for wound size imaging and also promising image processing tools for smart wound assessment and monitoring. Recent Advances: Some commercial devices are available for optical wound assessment but with limited possibilities compared to the power of multimodal imaging. With new low-cost devices and machine learning, wound assessment has become more robust and accurate. Wound size imaging not only provides area and volume but also the proportion of each tissue on the wound bed. Near-infrared and thermal spectral bands also enhance the classical visual assessment. Critical Issues: The ability to embed advanced imaging technology in portable devices such as smartphones and tablets with tissue analysis software tools will significantly improve wound care. As wound care and measurement are performed by nurses, the equipment needs to remain user-friendly, enable quick measurements, provide advanced monitoring, and be connected to the patient data management system. Future Directions: Combining several image modalities and machine learning, optical wound assessment will be smart enough to enable real wound monitoring, to provide clinicians with relevant indications to adapt the treatments and to improve healing rates and speed. Sharing the wound care histories of a number of patients on databases and through telemedicine practice could induce a better knowledge of the healing process and thus a better efficiency when the recorded clinical experience has been converted into knowledge through deep learning.

Predicting Clinical Outcomes in a Diabetic Foot Ulcer Population Using Fluorescence Imaging

OBJECTIVE

To retrospectively evaluate a cohort of patients with diabetic foot ulcers to determine if the rate of microcirculatory flow detected by fluorescence imaging within the wound and surrounding tissue is associated with healing outcomes.

METHODS

Tissue perfusion parameters used for the current analysis were the ingress rate (IR) within the wound bed (R01) and in an area remote from the wound (REF), as well as time to first blush. Wounds were then categorized based on their outcome (healed, healing, chronic nonhealing, partial foot amputation, proximal amputation below the knee) and compared between patients with positive or negative wound healing outcomes.

RESULTS

The final study cohort included 61 wounds and demonstrated that a higher IR within R01 and REF areas was significantly associated with positive outcomes, whereas time to first blush was not. A two-predictor logistic model found a significant relationship between IR (R01 and REF) and odds of wound healing.

CONCLUSIONS

Fluorescence imaging evaluation of a diabetic foot ulcer can provide valuable information on healing outcomes that can help determine if a wound is progressing toward healing and therefore may help inform the need for advanced wound modalities, referrals, and amputation.

Skin Autofluorescence as a Novel and Noninvasive Technology for Advanced Glycation End Products in Diabetic Foot Ulcers: A Systematic Review and Meta-analysis

OBJECTIVE

Skin autofluorescence (SAF) has been suggested as a novel and noninvasive technique for assessing tissue accumulation of advanced glycation end products in diabetes and related complications. The aim of this systematic review and meta-analysis was to evaluate the use of SAF in diabetic foot ulcers (DFUs).

DATA SOURCES

PubMed/MEDLINE and other digital databases.

STUDY SELECTION

The authors included studies comparing the SAF levels in patients with DFU with a non-DFU group to determine its association with DFU risk.

DATA EXTRACTION

Collected data included the SAF method and its values in DFU and non-DFU groups, covariates used in adjustment along with the unadjusted and/or multivariate adjusted odds ratios (ORs) for the association of SAF with DFU risk, and other study characteristics.

DATA SYNTHESIS

A total of six studies were included in this meta-analysis. Five studies that involved 611 participants were included to compare SAF methods. Compared with the non-DFU group, the DFU group showed a significantly increased level of SAF (standardized mean difference, 0.67; 95% confidence interval [CI], 0.32-1.01; P < .001). The results of meta-analysis of ORs revealed that the increased SAF level was independently associated with increased DFU risk in both unadjusted (OR, 3.16; 95% CI, 2.18-4.57; P < .001) and adjusted models (OR, 3.07; 95% CI, 1.95-4.81; P < .001).

CONCLUSIONS

These findings suggest that SAF could be useful as a novel and noninvasive technology to help determine DFU risk. However, further studies establishing its diagnostic and prognostic utilities are needed.

Reliability of ultrasound in evaluating the plantar skin and fat pad of the foot in the setting of diabetes

Ultrasound can be used to assess injury and structural changes to the soft-tissue structure of the foot. It may be useful to assess the feet of people with diabetes who are at increased risk of plantar soft-tissue pathological changes. The aim of this study was to determine if ultrasound measurements of plantar soft-tissue thickness and assessments of tissue acoustic characteristics are reliable in people with and without diabetes mellitus. A repeated measures design was used to determine intra-observer reliability for ultrasound measurements of plantar skin and fat pad thickness and intra- and inter-observer reliability of plantar skin and fat pad tissue characterisation assessments made at foot sites which are at risk of tissue injury in people with diabetes. Thickness measurements and tissue characterisation assessments were obtained at the heel and forefoot in both the unloaded and compressed states and included discrete layers of the plantar tissues: skin, microchamber, horizontal fibrous band, macrochamber and total soft-tissue depth. At each site, relative intra-observer reliability was achieved for the measurement of at least one plantar tissue layer. The total soft-tissue thickness measured in the unloaded state (ICC 0.925-0.976) demonstrated intra-observer reliability and is the most sensitive for detecting small change on repeated measures. Intra-observer agreement was demonstrated for tissue characteristic assessments of the skin at the heel (k = 0.70), fat pad at the lateral sesamoid region (k = 0.70) and both skin and fat pad at the second (k = 0.80, k = 0.70 respectively) and third metatarsal heads (k = 0.90, k = 0.79 respectively). However, acceptable inter-observer agreement was not demonstrated for any tissue characteristic assessment, therefore the use of multiple observers should be avoided when making these assessments.

Deteriorated regional calf microcirculation measured by contrast-free MRI in patients with diabetes mellitus and relation with physical activity

OBJECTIVE

To evaluate regional calf muscle microcirculation in people with diabetes mellitus (DM) with and without foot ulcers, compared to healthy control people without DM, using contrast-free magnetic resonance imaging methods.

METHODS

Three groups of subjects were recruited: non-DM controls, DM, and DM with foot ulcers (DM + ulcer), all with ankle brachial index (ABI) > 0.9. Skeletal muscle blood flow (SMBF) and oxygen extraction fraction (SMOEF) in calf muscle were measured at rest and during a 5-min isometric ankle plantarflexion exercise. Subjects completed the Yale physical activity survey.

RESULTS

The exercise SMBF (ml/min/100 g) of the medial gastrocnemius muscle were progressively impaired: 63.7 ± 18.9 for controls, 42.9 ± 6.7 for DM, and 36.2 ± 6.2 for DM + ulcer, p < 0.001. Corresponding exercise SMOEF was the lowest in DM + ulcers (0.48 ± 0.09). Exercise SMBF in the soleus muscle was correlated moderately with the Yale physical activity survey (r = 0.39, p < 0.01).

CONCLUSIONS

Contrast-free MR imaging identified progressively impaired regional microcirculation in medial gastrocnemius muscles of people with DM with and without foot ulcers. Exercise SMBF in the medial gastrocnemius muscle was the most sensitive index and was associated with HbA1c. Lower exercise SMBF in the soleus muscle was associated with lower Yale score.

[Major consequences of calcareous deposits in a diabetic foot]

This is a case report of a multimorbid 47-year-old male with calcareous deposits in his diabetic foot - a rare condition with major consequences. Within a few years after his forefoot amputation, heterotopic ossifications were seen, and clinically, foot deformity occurred. A wound difficult to heal appeared after an abscess, and an MRI showed unusual calcareous deposits. It is important to consider, if health workers have sufficient focus on neuropathy, and that too little focus on this complication may have consequences to the patient in terms of gait function and power of locomotion.

Segmentation Approaches for Diabetic Foot Disorders

Thermography enables non-invasive, accessible, and easily repeated foot temperature measurements for diabetic patients, promoting early detection and regular monitoring protocols, that limit the incidence of disabling conditions associated with diabetic foot disorders. The establishment of this application into standard diabetic care protocols requires to overcome technical issues, particularly the foot sole segmentation. In this work we implemented and evaluated several segmentation approaches which include conventional and Deep Learning methods. Multimodal images, constituted by registered visual-light, infrared and depth images, were acquired for 37 healthy subjects. The segmentation methods explored were based on both visual-light as well as infrared images, and optimization was achieved using the spatial information provided by the depth images. Furthermore, a ground truth was established from the manual segmentation performed by two independent researchers. Overall, the performance level of all the implemented approaches was satisfactory. Although the best performance, in terms of spatial overlap, accuracy, and precision, was found for the Skin and U-Net approaches optimized by the spatial information. However, the robustness of the U-Net approach is preferred.

Stimulation TcPO2 Testing Improves Diagnosis of Peripheral Arterial Disease in Patients With Diabetic Foot

BACKGROUND

All diagnostic procedures of peripheral arterial disease (PAD) in diabetic foot (DF) are complicated due to diabetes mellitus and its late complications.The aim of our study is to enhance diagnosis of PAD using a novel transcutaneous oximetry (TcPO2) stimulation test.

METHODS

The study comprised patients with mild-to-moderate PAD(WIfI-I 1 or 2) and baseline TcPO2 values of 30-50 mmHg.TcPO2 was measured across 107 different angiosomes. Stimulation examination involved a modification of the Ratschow test. All patients underwent PAD assessment (systolic blood pressures (SBP), toe pressures (TP), the ankle-brachial indexes (ABI) and toe-brachial indexes (TBI), duplex ultrasound of circulation). Angiosomes were divided into two groups based on ultrasound findings: group M(n=60) with monophasic flow; group T(n=47) with triphasic flow. Large vessel parameters and TcPO2 at rest and after exercise (minimal TcPO2, changes in TcPO2 from baseline (Δ,%), TcPO2 recovery time) measured during the stimulation test were compared between study groups.

RESULTS

During the TcPO2 stimulation exercise test, group M exhibited significantly lower minimal TcPO2 (26.2 ± 11.1 vs. 31.4 ± 9.4 mmHg; p<0.01), greater Δ and percentage decreases from resting TcPO2 (p=0.014 and p=0.007, respectively) and longer TcPO2 recovery times (446 ± 134 vs. 370 ± 81ms;p=0.0005) compared to group T. SBPs, TPs and indexes were significantly lower in group M compared to group T. Sensitivity and specificity of TcPO2 stimulation parameters during PAD detection increased significantly to the level of SBP, ABI, TP and TBI.

CONCLUSION

Compared to resting TcPO2, TcPO2 measured during stimulation improves detection of latent forms of PAD and restenosis/obliterations of previously treated arteries in diabetic foot patients.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov [https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0009V7W&selectaction=Edit&uid=U0005381&ts=2&cx=3j24u2], identifier NCT04404699.

X-Ray Versus Magnetic Resonance Imaging in Diabetic Foot Osteomyelitis: A Clinical Comparison

OBJECTIVE

Radiographic imaging is an important diagnostic tool in diabetic foot osteomyelitis (DFO). It is unknown whether DFO cases diagnosed with conventional X-ray versus positive Magnetic Resonance Imaging (MRI) differ regarding epidemiology and treatment outcome. Theoretically, signs of inflammation on MRI without bone lesions might be easier to treat.

METHODS

Our clinical pathway for diabetic foot infections discourages the use of MRI for the diagnosis of DFO. We compared the epidemiology and therapy of non-amputated DFO with positive features on conventional X-ray, MRI, or both. Radiology specialists interpreted the images. The intraoperative aspect of bone during amputation and the results of bone cultures were considered the gold standard for DFO diagnosis.

RESULTS

We prospectively followed 390 DFO episodes in 186 adult patients for a median of 2.9 years and performed 318 conventional X-rays (median costs 100 Swiss Francs; 100 US$) and 47 (47/390; 12%) MRI scans (median 800 Swiss Francs; 800 US $). Among them, 18 episodes were associated with positive MRI findings but lacked bone lesions on X-ray. After debridement, the median duration of systemic antibiotics was 28 days for MRI-only episodes and 30 days for X-ray-positive cases (Wilcoxonranksum- test; p=0.26). The corresponding median numbers of surgical debridements were 1 and 1; and recurrence was witnessed in 25% and 28%, respectively. In multivariate logistic regression analysis, MRI-only episodes did not alter the remission rate (odds ratio 0.5, 95%CI 0.1-5.2).

CONCLUSION

According to our clinical pathway, DFO episodes with positive MRI findings only did not differ epidemiologically from the remaining DFO cases and did not influence the choice of therapy nor remission rate.

Sonoelastographic Evaluation of the Achilles Tendon in Patients With Type 2 Diabetes Mellitus

Diabetic foot is one of the dreaded complications of diabetes mellitus (DM). Alterations of the Achilles tendon (AT) may contribute to development of foot ulcers in diabetic patients. We evaluated the sonoelastographic abnormalities of the AT in 61 healthy volunteers and 81 patients with type 2 DM. The patients were further divided into those with and without peripheral neuropathy (PN). The AT thickness was measured in the proximal, middle and distal portions. Alterations in echo pattern were noted. The patients were found to have thicker tendons than the healthy volunteers (p < 0.01). Alterations in the echo pattern of the AT were more common in patients compared with healthy volunteers (p < 0.01). The shear wave velocity in the distal one-third of the AT was measured using shear wave elasticity imaging. Mean shear wave velocity values obtained were lower in patients compared with healthy volunteers (p < 0.001). No significant difference was found in the sonoelastographic findings of the AT in patients with and without PN. We conclude that there is softening, thickening and alterations in echo pattern of the AT in the form of hypoechogenicity, loss of fibrillar pattern and calcification at insertion in patients with type 2 DM, and these alterations could occur independent of onset of PN.

Visualizing and quantifying cutaneous microvascular reactivity in humans by use of optical coherence tomography: impaired dilator function in diabetes

The pathophysiology and time course of impairment in cutaneous microcirculatory function and structure remain poorly understood in people with diabetes, partly due to the lack of investigational tools capable of directly imaging and quantifying the microvasculature in vivo. We applied a new optical coherence tomography (OCT) technique, at rest and during reactive hyperemia (RH), to assess the skin microvasculature in people with diabetes with foot ulcers (DFU, n = 13), those with diabetes without ulcers (DNU, n = 9), and matched healthy controls (CON, n = 13). OCT images were obtained from the dorsal part of the foot at rest and following 5 min of local ischemia induced by inflating a cuff around the thigh at suprasystolic level (220 mmHg). One-way ANOVA was used to compare the OCT-derived parameters (diameter, speed, flow rate, and density) at rest and in response to RH, with repeated-measures two-way ANOVA performed to analyze main and interaction effects between groups. Data are means ± SD. At rest, microvascular diameter in the DFU (84.89 ± 14.84 µm) group was higher than CON (71.25 ± 7.6 µm, P = 0.012) and DNU (71.33 ± 12.04 µm, P = 0.019) group. Speed in DFU (65.56 ± 4.80 µm/s, P = 0.002) and DNU (63.22 ± 4.35 µm/s, P = 0.050) were higher than CON (59.58 ± 3.02 µm/s). Microvascular density in DFU (22.23 ± 13.8%) was higher than in CON (9.83 ± 2.94%, P = 0.008), but not than in the DNU group (14.8 ± 10.98%, P = 0.119). All OCT-derived parameters were significantly increased in response to RH in the CON group (all P < 0.01) and DNU group (all P < 0.05). Significant increase in the DFU group was observed in speed (P = 0.031) and density (P = 0.018). The change in density was lowest in the DFU group (44 ± 34.1%) compared with CON (199.2 ± 117.5%, P = 0.005) and DNU (148.1 ± 98.4, P = 0.054). This study proves that noninvasive OCT microvascular imaging is feasible in people with diabetes, provides powerful new physiological insights, and can distinguish between healthy individuals and patients with diabetes with distinct disease severity.

Quantifying dermal microcirculatory changes of neuropathic and neuroischemic diabetic foot ulcers using spatial frequency domain imaging: a shade of things to come?

INTRODUCTION

The use of non-invasive vascular and perfusion diagnostics are an important part of assessing lower extremity ulceration and amputation risk in patients with diabetes mellitus. Methods for detecting impaired microvascular vasodilatory function in patients with diabetes may have the potential to identify sites at risk of ulceration prior to clinically identifiable signs. Spatial frequency domain imaging (SFDI) uses patterned near-infrared and visible light spectroscopy to determine tissue oxygen saturation and hemoglobin distribution within the superficial and deep dermis, showing distinct microcirculatory and oxygenation changes that occur prior to neuropathic and neuroischemic ulceration.

RESEARCH DESIGNS AND METHODS

35 patients with diabetes mellitus and a history of diabetic foot ulceration were recruited for monthly imaging with SFDI. Two patients who ulcerated during the year-long longitudinal study were selected for presentation of their clinical course alongside the dermal microcirculation biomarkers from SFDI.

RESULTS

Patient 1 developed a neuropathic ulcer portended by a focal increase in tissue oxygen saturation and decrease in superficial papillary hemoglobin concentration 3 months prior. Patient 2 developed bilateral neuroischemic ulcers showing decreased tissue oxygen saturation and increased superficial papillary and deep dermal reticular hemoglobin concentrations.

CONCLUSIONS

Wounds of different etiology show unique dermal microcirculatory changes prior to gross ulceration. Before predictive models can be developed from SFDI, biomarker data must be correlated with the clinical course of patients who ulcerate while being followed longitudinally.

TRIAL REGISTRATION NUMBER

NCT03341559.

Utilization of smartphone and tablet camera photographs to predict healing of diabetes-related foot ulcers

The objective of this study was to build a machine learning model that can predict healing of diabetes-related foot ulcers, using both clinical attributes extracted from electronic health records (EHR) and image features extracted from photographs. The clinical information and photographs were collected at an academic podiatry wound clinic over a three-year period. Both hand-crafted color and texture features and deep learning-based features from the global average pooling layer of ResNet-50 were extracted from the wound photographs. Random Forest (RF) and Support Vector Machine (SVM) models were then trained for prediction. For prediction of eventual wound healing, the models built with hand-crafted imaging features alone outperformed models built with clinical or deep-learning features alone. Models trained with all features performed comparatively against models trained with hand-crafted imaging features. Utilization of smartphone and tablet photographs taken outside of research settings hold promise for predicting prognosis of diabetes-related foot ulcers.

Visualization of Wound Healing Progression With Near Infrared Spectroscopy: A Retrospective Study

OBJECTIVE

The aim of this retrospective study is to determine if near infrared spectroscopy (NIRS) can be used to evaluate wounds and adjacent soft tissues to identify patterns involved in tissue oxygenation and wound healing as well as predict which wounds may or may not heal.

MATERIALS AND METHODS

In this study, 25 patients with either diabetic foot ulcers or venous leg ulcers were examined retrospectively to determine if NIRS could be used to predict which wounds may or may not close. All patients had either diabetic or venous ulcers and were being actively treated in the clinic. Regardless of the treatment rendered, all wounds were tracked with NIRS at regular intervals. Retrospectively, the de-identified images were reviewed to determine any patterns that might exist. Wound bed and periwound oxygenation patterns were observed and classified, including correlation with both the clinical appearance and the NIRS images. Images of wounds that closed and those that did not were compared.

RESULTS

Four distinct patterns of tissue oxygenation that appeared to have some value for predicting which wounds would heal, and which would not, were identified among the 25 patients. A mechanism has also been proposed to try to explain the patterns of healing observed; Hyperperfusion, Imbibition, Neovascularization, and Trailing (HINT) describes various aspects of these patterns.

CONCLUSIONS

As with any imaging technology, both qualitative and quantitative data are used to determine what is happening clinically. This study represents an early attempt to understand the role of NIRS and percent oxygenated hemoglobin in the wound healing process. It also lays the groundwork for identifying patterns associated with wound closure.