Digital Planimetry With a New Adaptive Calibration Procedure Results in Accurate and Precise Wound Area Measurement at Curved Surfaces

BACKGROUND

The purpose of this study was to determine the accuracy of wound area measurement at a curved surface using a digital planimetry (DP) with the newly proposed adaptive calibration.

METHODS

Forty wound shapes were printed and placed at the side surfaces of cylinders with diameters of 9.4 and 6.2 cm. Area measurements were carried out using a commercial device SilhouetteMobile (Aranz, New Zealand) and the planimetric app Planimator. Planimetric area measurements were carried out using 2 one-dimensional calibration markers placed above and below the wound shape. The method of adaptive calibration for DP was described. Reference area values of wound shapes were obtained by pixel counting on digital scans made with an optical scanner. Relative errors (REs) and relative differences (RDs) for area measurements were analyzed.

RESULTS

The median of REs for the DP with adaptive calibration (DPwAC) was equal to 0.60% and was significantly smaller than the median for the SilhouetteMobile device (SMD) (2.65%), and significantly smaller than the median for the DP (2.23%). The SD of RDs for the DPwAC of 0.87% was considerably lower than for the SMD (6.45%), and for the DP without adaptive calibration (2.51%). The mean of RDs for the DPwAC (0.082%) was not significantly different from zero, which means that the systematic error was not present for the DPwAC.

CONCLUSIONS

The use of the adaptive calibration in DP to measure the areas at curved surface resulted in a significant increase of accuracy and precision, and removal of systematic error. The DPwAC revealed 4.4 times lower error and 7.4 times higher precision of area measurement at curved surfaces than the SMD.

Insulin, but Not Metformin, Supports Wound Healing Process in Rats with Streptozotocin-Induced Diabetes

PURPOSE

Optimal glycemic control is crucial for proper wound healing in patients with diabetes. However, it is not clear whether other antidiabetic drugs support wound healing in mechanisms different from the normalization of blood glucose control. We assessed the effect of insulin and metformin administration on the wound healing process in rats with streptozotocin-induced diabetes.

METHODS

The study was conducted on 200 male Wistar rats with streptozotocin-induced diabetes. In the last phase of the study, 45 rats, with the most stable glucose levels in the range of 350-500 mg/dL, were divided into three groups: group I received human non-protamine insulin subcutaneously (5 IU/kg body mass) once a day, group II received metformin intragastrically (500 mg/kg b.m.), and group III (control) was given saline subcutaneously. After 14 days of antidiabetic treatment, a 2 cm × 2 cm thin layer of skin was cut from each rat's dorsum and a 4 cm disk with a hole in its center was sewn in to stabilize the skin and standardize the healing process. The wound healing process was followed up for 9 days, with assessment every 3 days. Biopsy samples were subjected to hematoxylin and eosin staining and immunohistochemical assays.

RESULTS

Analysis of variance revealed significant influence of treatment type (insulin, control, or metformin) on the relative change in wound surface area. The wound healing process in rats treated with insulin was more effective than in the metformin and control groups. Wound tissue samples taken from the insulin-treated animals presented significantly lower levels of inflammatory infiltration. Immunohistochemical assessment showed the greatest density of centers of proliferation Ki-67 in insulin-treated animals.

CONCLUSION

These results suggest that an insulin-based treatment is more beneficial than metformin, in terms of accelerating the wound healing process in an animal model of streptozocin-induced diabetes.

Efficacy of automatic bolus calculator with automatic speech recognition in patients with type 1 diabetes: A randomized cross-over trial

BACKGROUND

Patients using an insulin pump as part of their diabetes treatment need to calculate insulin bolus doses to compensate for a meal. Some patients do not modify their meal boluses according to changes in the amount and composition of food products in a meal. The lack of correct meal boluses leads to unstable, and therefore harmful, blood glucose levels. The aim of the present study was to test a system supporting bolus determination based on a voice description of a meal.

METHODS

The bolus calculator developed (VoiceDiab) consists of a smartphone application and three remote servers for automatic speech recognition, text analysis, and insulin dosage calculation. Forty-four people with type 1 diabetes (T1D) treated with continuous subcutaneous insulin infusion finished the randomized cross-over study. Patients were randomly allocated to the group in which the VoiceDiab system supported bolus calculation or to an unsupported group, in which patients or their caregivers calculated boluses. After a 14-day washout period, patients from the supported group were switched to the unsupported group, whereas those in the unsupported group were switched to the supported group.

RESULTS

There was a significant difference between the supported and unsupported groups in the percentage of patients with 2-h postprandial glycemia within the 70-180 mg/dL range (58.6% vs 46.6%, respectively; P = 0.031).

CONCLUSIONS

The VoiceDiab system improves postprandial glucose control without increasing the time in hyperglycemia or hypoglycemia. Therefore, it may be useful in the treatment of patients with diabetes on intensive insulin therapy.

Ways to increase precision and accuracy of wound area measurement using smart devices: Advanced app Planimator

Introduction

Wound surface area measurement is important as therapeutic decisions may depend on the change of wound surface area over time. Digital planimetry is a popular technique in wound area measurement. It is accurate and repeatable when calibration is performed with 2 rulers placed at opposite sides of a wound. The aim of the current study was improving accuracy and precision of wound area measurement using capabilities of smart devices.

Methods

The correction of area measurement based on calculated camera tilt angle and the calculation of calibration coefficient of linear dimensions as weighted average were proposed. These and other improvements were applied in the Planimator app for Android, which was then used in the study. Accuracy and precision of the Planimator app were compared to the Visitrak device, the SilhouetteMobile device, the AreaMe software, and to the digital planimetry based on 2-ruler calibration with pictures taken by the smartphone, compact, and D-SLR cameras. Areas of 40 wound shapes of area ranged from 0.14 to 31.72 cm² were measured with each device. Medians of relative errors (REs) were compared in the accuracy tests and standard deviations (SDs) of relative differences (RDs) were compared in the tests of precision.

Results

The median of REs for the Planimator app was not significantly different from the medians of REs for the digital planimetry based on pictures from the compact or D-SLR cameras, but it was significantly lower than the medians of REs for the Visitrak and SilhouetteMobile devices, the AreaMe software and the digital planimetry based on pictures from a smartphone camera. The SD of RDs for the Planimator app was not significantly different from the SDs of RDs for the digital planimetry based on pictures from the compact or D-SLR cameras, but it was significantly lower than the SDs of RDs for the Visitrak and SilhouetteMobile devices, the AreaMe software and the digital planimetry based on pictures from a smartphone camera. The Planimator app installed at a smartphone revealed to be 2-fold more accurate and 1.5-fold more precise than the measurements with using ImageJ software based on pictures taken with the same smartphone.

Conclusions

The Planimator app occurred to have the same accuracy and precision as measurements with digital planimetry with 2-ruler calibration and based on pictures from a compact camera or a D-SLR camera. This app showed better accuracy and precision than the Visitrak and SilhouetteMobile devices, the AreaMe software and the digital planimetry based on pictures from a smartphone camera.

Human endothelial cells hollow fiber membrane bioreactor as a model of the blood vessel for in vitro studies

Human endothelial cells are used in experimental models for studying in vitro pathophysiological mechanisms of different diseases. We developed an original bioreactor, which can simulate human blood vessel, with capillary polysulfone membranes covered with the human umbilical vein endothelial cells (HUVECs) and we characterized its properties. The elaborated cell seeding and culturing procedures ensured formation of a confluent cell monolayer on the inside surface of capillaries within 24 h of culturing under the shear stress of 6.6 dyn/cm(2). The optimal density of cells to be seeded was 60,000 cells/cm(2). Labeling HUVECs with carboxyfluorescein succinimidyl ester (CFSE) did not influence cells' metabolism. Flow cytometry-based analysis of HUVECs stained with CFSE demonstrated that in a presence of the shear stress cells' proliferation was much inhibited (after 72 h proliferation index was equal to 1.9 and 6.2 for cultures with and without shear stress, respectively) and the monolayer was formed mainly due to migration and spreading of cells that were physiologically elongated in a direction of the flow. Monitoring of cells' metabolism showed that HUVECs cultured in a presence of the shear stress preferred anaerobic metabolism and they consumed 1.5 times more glucose and produced 2.3 times more lactate than the cells cultured under static conditions. Daily von Willebrand factor production by HUVECs was near 2 times higher in a presence of the shear stress. The developed model can be used for at least 3 days in target studies under conditions mimicking the in vivo state more closely than the static HUVEC cultures.

Wound Area Measurement with Digital Planimetry: Improved Accuracy and Precision with Calibration Based on 2 Rulers

Introduction

In the treatment of chronic wounds the wound surface area change over time is useful parameter in assessment of the applied therapy plan. The more precise the method of wound area measurement the earlier may be identified and changed inappropriate treatment plan. Digital planimetry may be used in wound area measurement and therapy assessment when it is properly used, but the common problem is the camera lens orientation during the taking of a picture. The camera lens axis should be perpendicular to the wound plane, and if it is not, the measured area differ from the true area.

Results

Current study shows that the use of 2 rulers placed in parallel below and above the wound for the calibration increases on average 3.8 times the precision of area measurement in comparison to the measurement with one ruler used for calibration. The proposed procedure of calibration increases also 4 times accuracy of area measurement. It was also showed that wound area range and camera type do not influence the precision of area measurement with digital planimetry based on two ruler calibration, however the measurements based on smartphone camera were significantly less accurate than these based on D-SLR or compact cameras. Area measurement on flat surface was more precise with the digital planimetry with 2 rulers than performed with the Visitrak device, the Silhouette Mobile device or the AreaMe software-based method.

Conclusion

The calibration in digital planimetry with using 2 rulers remarkably increases precision and accuracy of measurement and therefore should be recommended instead of calibration based on single ruler.

Validation of a hemoglobin A1c model in patients with type 1 and type 2 diabetes and its use to go beyond the averaged relationship of hemoglobin A1c and mean glucose level

Background

Glycated hemoglobin A_1c (HbA_1c) has been used as an index of glycemic control in the management, guidance, and clinical trials of diabetic patients for the past 35 years. The aim of this study was to validate the HbA_1c model in patients with type 1 and type 2 diabetes and to use it to support interpretation of HbA_1c in different clinical situations.

Methods

The HbA_1c model was identified in 30 patients (15 with type 1 diabetes and 15 with type 2 diabetes) by estimating the overall glycation rate constant (k), based on results of continuous glucose monitoring. The model was validated by assessing its ability to predict HbA_1c changes in cultures of erythrocytes in vitro and to reproduce results of the A1C-Derived Average Glucose (ADAG) study. The model was used to simulate the influence of different glucose profiles on HbA_1c.

Results

The mean k was equal to 1.296 ± 0.216 × 10⁻⁹ l mmol⁻¹ s⁻¹ with no difference between type 1 and type 2 diabetes. The mean coefficient of variation of k was equal to 16.7%. The model predicted HbA_1c levels in vitro with a mean absolute difference less than 0.3% (3.3 mmol/mol). It reproduced the linear relationship of HbA_1c and mean glucose levels established in the ADAG study. The simulation experiments demonstrated that during periods of unstable glycemic control, glycemic profiles with the same mean glucose might result in much different HbA_1c levels.

Conclusions

Patients with type 1 and type 2 diabetes are characterized by the same mean value of k, but there is considerable interindividual variation in the relationship of HbA_1c and mean glucose level. Results suggest that reciprocal changes in glycation rate and the life span of erythrocytes exist in a wide range of HbA_1c values. Thus, for an average patient with diabetes, no modifications of parameters of the glycation model are required to obtain meaningful HbA_1c predictions. Interpreting HbA_1c as a measure of the mean glucose is fully justified only in the case of stable glycemia. The model and more frequent tests of HbA_1c might be used to decrease ambiguity of interpreting HbA_1c in terms of glycemic control.

Accuracy and precision of selected wound area measurement methods in diabetic foot ulceration

AIM

The present study assesses precision and accuracy of four selected methods of wound area measurements in diabetic foot wounds.

MATERIALS AND METHODS

The areas of 16 wound shapes were measured using linear measurement with elliptical estimation (Elliptical method), using the Visitrak™ (Smith & Nephew, London, United Kingdom) device, the SilhouetteMobile™ device (ARANZ Medical Ltd., Christchurch, New Zealand), and the TeleDiaFoS system (Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland). The actual area of a wound shape was determined with a tested scanner and specifically developed software. Accuracy of the area measurement method was assessed by the relative error (RE), whereas precision was assessed by the coefficient of variation (CV).

RESULTS

The overall absolute REs were 13.3%, 6.8%, 2.1%, and 2.3% for the Elliptical method, the Visitrak device, the TeleDiaFoS system, and the SilhouetteMobile device, respectively. The accuracy of the Visitrak device was remarkably reduced for wound areas smaller than 2 cm². The overall CVs were 6.0%, 6.3%, 1.6%, and 3.1% for the Elliptical method, the Visitrak device, the TeleDiaFoS system, and the SilhouetteMobile device, respectively. The precision of the Visitrak device was revealed to be remarkably lower for small wounds (<2 cm²).

CONCLUSIONS

The Elliptical method gives overestimation up to 33%; thus, it should not be used in applications where the actual wound area is an important parameter (like the prediction of wound healing). The TeleDiaFoS system and the SilhouetteMobile device showed the best accuracy of all used methods; however, the precision of the TeleDiaFoS system was revealed to be higher than the precision of the SilhouetteMobile device. The accuracy and the precision of the Visitrak device are significantly reduced for wounds smaller than 2 cm².

What we can really expect from telemedicine in intensive diabetes treatment: 10 years later

During the last 10 years many new telematic systems aiming at support of diabetes treatment have been designed and developed. Most systems that were applied in clinical randomized trials used the classical approach, with data transfers from patients performed usually once every few days. In the few available meta-analyses of these trials, a significant improvement of the mean hemoglobin A1c was demonstrated in patients using telematic systems. However, the magnitude of this improvement in comparison with the control groups was lower than expected. This conclusion was confirmed by results of the IDEATel study involving more than 1,600 patients over a period of 5 years. It might by hypothesized that in some groups of patients continuous telecare with frequent contacts between patients and the care provider during each day should be required. This hypothesis is confirmed by the results of the clinical trials applying real-time diabetes monitoring systems. However, the increased frequency of the data transfers and checkups requires a new model for technology-supported care. The new model should connect together the ubiquitous data transfer with an automatically selected optimal frequency, the automatic assessment of the data coupled with quicker feedback from the decision support system or from the provider, and selection of the optimal time for the patient's face-to-face visit in the clinic. All this new future implementations together with already confirmed advantages of the telematic support, such as the increase of self-confidence of the patient, will hopefully give real benefits for the patients.

Area of the diabetic ulcers estimated applying a foot scanner-based home telecare system and three reference methods

BACKGROUND

Diabetic foot ulcer area is a basic parameter used for monitoring the wound healing and effectiveness of the treatment applied. TeleDiaFoS (developed earlier in collaboration with the Department and Clinic of Gastroenterology and Metabolic Diseases, Medical University of Warsaw, Warsaw, Poland) is one of just a few systems available that make possible monitoring of the wound size remotely based on the foot scans transmitted to the physician from a patient's home. The aim of this study was to compare the diabetic foot ulcer areas measured using TeleDiaFoS with the results obtained using three reference methods.

METHODS

The reference measurements were conducted using the elliptical method with a ruler, the wound tracing method and planimetrics with the Visitrak (Smith & Nephew, London, UK) system, and the pattern-coded structured light method with the Silhouette (ARANZ Medical, Christchurch, New Zealand) system. Regression and Bland-Altman analyses were performed. The study group consisted of 23 diabetes patients with plantar foot ulcers.

RESULTS

Thirty-three wounds were successfully examined. The measurement method influenced the measured area significantly (P=0.00005). The correlation coefficients between TeleDiaFoS and the ruler, Visitrak, and Silhouette methods were 0.949, 0.985, and 0.987, and the limits of agreement equaled -1.3±5.5 cm(2), -0.4±2.2 cm(2), and -0.6±2.1 cm(2), respectively. The strong linear relationships obtained can be used to convert the wound area measured with TeleDiaFoS to the corresponding value of each of the reference methods.

CONCLUSIONS

The results indicate that the wound area of plantar ulcers in diabetes might be monitored effectively using the TeleDiaFoS system based on the foot scans that the patient can produce at home with no assistance of other persons.

A new imaging and data transmitting device for telemonitoring of diabetic foot syndrome patients

BACKGROUND

Proper healing of ulcers and wounds on the feet of diabetes patients is important in order to prevent amputation. If the wound area reduction during the first 4 weeks of the treatment is not 40% or more, reevaluation of the treatment is necessary. The wound area evaluation is not complicated when the patient stays at a hospital, but when he or she goes home the physician does not have a tool allowing monitoring of the wound area.

METHODS AND RESULTS

The aim of the present article is to present a new device able to take a wound picture and send it automatically to the database. This device, called the Patient's Module (PM), is also able to download data from the memories of blood pressure and blood glucose meters and send the data to the database. The PM is able to operate within the TeleDiaFoS system (developed earlier in collaboration with the Department and Clinic of Gastroenterology and Metabolic Diseases, Medical University of Warsaw, Warsaw, Poland) aimed at monitoring of treatment of patients with diabetic foot syndrome. The PM was tested on 10 type 2 diabetes patients during a 3-month period.

CONCLUSIONS

The study revealed that the PM can be used as a home telemonitoring device, and the analysis of the data sent from patient's home enables the assessment of wound healing progress, giving the physician the possibility for earlier change of the treatment if the wound area reduction is not satisfactory.

Monitoring of diabetic foot syndrome treatment: some new perspectives

Diabetic foot syndrome (DFS) is one of the major complications of diabetes, and it can lead to foot amputations. It is very important to assure good medical care for diabetic patients not only during their stay at hospital but also at home. Telecare can be one good solution for extending medical care to patients' homes. There are some reports regarding the application of new technologies in this field. The standard current model of telecare of DFS includes experts at hospital who conduct clinical examinations and decision making at a distance, in close cooperation with a visiting nurse and the patient. In the present paper a new paradigm of the DFS's telecare is introduced, which eliminates the visiting nurse. The designed and developed TeleDiaFoS system consists of a traditional database and mobile patient's module (PM) allowing for documentation of the foot images as well as the results of blood glucose and blood pressure measurements taken by the patient himself at home. A 2-year validation of the TeleDiaFoS system on 10 DFS patients (3 months each) proved its usefulness and led to acceptance of this type of technical support by patients and physicians. The designed and developed system and proposed sterilization procedure of the PM have been found to be easy to use by the patient at home.

Microdialysis technique as a monitoring system for acute complications of diabetes

The objective of the study was to establish the quasi-continuous courses, using microdialysis technique, of glucose, lactate, and glycerol concentrations in interstitial fluid of abdominal adipose tissue during the standard treatment of acute diabetes complications. Clinical studies were carried out on 31 diabetic patients during the initial 48 h of the treatment. In all but two obese female patients with hyperglycemic hyperosmolar state (HHS) did glucose concentration in perfusion fluid (PF) reflect concentration in capillary blood. The recovery of glucose correlated with patients' body mass index (r = 0.55). It was significantly higher in lean and overweight patients (91 +/- 15%) than in obese patients (55 +/- 31%). The course of lactate concentration in PF coincided with the course in venous blood (2.1 +/- 0.3 mmol/L vs. 2.0 +/- 0.5 mmol/L, P = 0.35). Glycerol concentration was 267 +/- 41 micromol/L and 133 +/- 40 micromol/L in PF and venous blood, respectively (P = 0.004). The study indicated that microdialysis may be an effective tool to monitor concentration of different metabolites in interstitial fluid of the adipose tissue during treatment of the acute complications of diabetes. Applicability of the technique in the monitoring of HHS, especially in obese female patients, needs further investigation.