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Mirdell, Robin
Publications (5 of 5) Show all publications
Mirdell, R. (2019). Blood Flow Dynamics in Burns. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Blood Flow Dynamics in Burns
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]


Burns of intermediate thickness are hard to evaluate clinically. This often leads to unnecessary delays of up to 14 days before a surgical decision can be made. To counter this, several objective methods have been developed to determine the healing potential of the wound. Over the years, measurement of perfusion has proven to be the most successful method for evaluation of healing potential. Laser Doppler imaging (LDI) is currently the most used method and can determine surgical need 2 days after injury with an accuracy >90%.  

There are however emerging techniques like laser speckle contrast imaging (LSCI), which also measure perfusion. LSCI have several advantages over LDI and is easier to use. LSCI can also investigate aspects of the microcirculation, previously not possible with LDI. The aim of this thesis was to investigate LSCI’s ability to evaluate surgical need in burns of indeterminate partial-thickness.  

The first objective was to investigate the dynamics of perfusion the first 14 days after injury. The purpose was to find the optimal time-window for perfusion measurements. The next goal was to determine the accuracy of different perfusion cut-offs. In this second study, the benefit of a subsequent measurement was also investigated. After this, interobserver variation between different profession groups was studied. Both the agreement of perfusion measurements and observer assessments were evaluated. Finally, cardiac vasomotion in combination with perfusion (pulsatility) was investigated as a method to determine surgical need <48 hours after injury.  


Perfusion was measured in a total of 77 patients at the Department of Plastic Surgery, Hand Surgery and Burns at Linköping University Hospital, Sweden. Most of these patients were children and the most common type of burn was scalds. A laser speckle contrast imager (PeriCam PSI System, Perimed AB, Järfälla, Sweden) was used to measure perfusion.  


In the first paper we showed a clear relation between perfusion dynamics and the healing potential of the wound. The changes in perfusion were largest the first 5 days after injury, why this time interval was selected for subsequent papers. Perfusion measurements done day 3-4 after injury could predict surgical need with a sensitivity of 100% (95% CI: 83.9-100%) and a specificity of 90.4% (95% CI: 83.8-94.9%). If two measurements were used, <24 hours and 3-4 days after injury, the accuracy was 100%. Furthermore, we found that different observers could consistently predict perfusion, while there was a large variation in their clinical assessments. This was not improved by extensive burn experience. Finally, pulsatility could be used to predict surgical need the same day as the injury occurred with a sensitivity of 100% (95% CI: 88.1-100%) and a specificity of 98.8% (95% CI: 95.7- 99.9%).  


LSCI is a promising method for evaluation of burns and provides several benefits over LDI. The surgical need of burns can be determined mere hours after injury when pulsatility is measured. However, the benefits of early scald diagnostics in children with LSCI need to be evaluated in a prospective study before the method is ready for routine clinical use.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2019. p. 83
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1720
National Category
Medical Laboratory and Measurements Technologies
urn:nbn:se:liu:diva-162216 (URN)10.3384/diss.diva-162216 (DOI)9789179299453 (ISBN)
Public defence
2019-12-20, Berzeliussalen, Campus US, Linköpings Universitet, Linköping, 13:00 (English)
Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2019-12-12Bibliographically approved
Elmasry, M., Mirdell, R., Tesselaar, E., Farnebo, S., Sjöberg, F. & Steinvall, I. (2019). Laser speckle contrast imaging in children with scalds: Its influence on timing of intervention, duration of healing and care, and costs. Burns, 45(4), 798-804
Open this publication in new window or tab >>Laser speckle contrast imaging in children with scalds: Its influence on timing of intervention, duration of healing and care, and costs
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2019 (English)In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 45, no 4, p. 798-804Article in journal (Refereed) Published
Abstract [sv]


Scalds are the most common type of burn injury in children, and the initial evaluation of burn depth is a problem. Early identification of deep dermal areas that need excision and grafting would save unnecessary visits and stays in hospital. Laser speckle contrast imaging (LSCI) shows promise for the evaluation of this type of burn. The aim of this study was to find out whether perfusion measured with LSCI has an influence on the decision for operation, duration of healing and care period, and costs, in children with scalds.


We studied a group of children with scalds whose wounds were evaluated with LSCI on day 3–4 after injury during the period 2012–2015. Regression (adjustment for percentage total body surface area burned (TBSA%), age, and sex) was used to analyse the significance of associations between degree of perfusion and clinical outcome.


We studied 33 children with a mean TBSA% of 6.0 (95% CI 4.4–7.7)%. Lower perfusion values were associated with operation (area under the receiver-operating characteristic curve 0.86, 95% CI 0.73–1.00). The perfusion cut-off with 100% specificity for not undergoing an operation was ≥191 PU units (66.7% sensitivity and 72.7% accurately classified). Multivariable analyses showed that perfusion was independently associated with duration of healing and care period.


Lower perfusion values, as measured with LSCI, are associated with longer healing time and longer care period. By earlier identification of burns that will be operated, perfusion measurements may further decrease the duration of care of burns in children with scalds.

Place, publisher, year, edition, pages
Elsevier, 2019
Laser speckle contrast imaging; Burns; Scalds; Perfusion; Outcome; Children
National Category
Other Clinical Medicine
urn:nbn:se:liu:diva-154872 (URN)10.1016/j.burns.2019.02.001 (DOI)000467914900006 ()30827850 (PubMedID)2-s2.0-85062153561 (Scopus ID)

Funding agencies: Linkoping University, Linkoping, Sweden; Burn Centre, Department of Hand Surgery, Plastic Surgery, and Burns

Available from: 2019-03-02 Created: 2019-03-02 Last updated: 2019-07-01Bibliographically approved
Cirillo, M. D., Mirdell, R., Sjöberg, F. & Pham, T. (2019). Time-Independent Prediction of Burn Depth using Deep Convolutional Neural Networks. Journal of Burn Care & Research, 40(6), 857-863
Open this publication in new window or tab >>Time-Independent Prediction of Burn Depth using Deep Convolutional Neural Networks
2019 (English)In: Journal of Burn Care & Research, ISSN 1559-047X, E-ISSN 1559-0488, Vol. 40, no 6, p. 857-863Article in journal (Refereed) Published
Abstract [en]

We present in this paper the application of deep convolutional neural networks, which are a state-of-the-art artificial intelligence (AI) approach in machine learning, for automated time-independent prediction of burn depth. Colour images of four types of burn depth injured in first few days, including normal skin and background, acquired by a TiVi camera were trained and tested with four pre-trained deep convolutional neural networks: VGG-16, GoogleNet, ResNet-50, and ResNet-101. In the end, the best 10-fold cross-validation results obtained from ResNet- 101 with an average, minimum, and maximum accuracy are 81.66%, 72.06% and 88.06%, respectively; and the average accuracy, sensitivity and specificity for the four different types of burn depth are 90.54%, 74.35% and 94.25%, respectively. The accuracy was compared to the clinical diagnosis obtained after the wound had healed. Hence, application of AI is very promising for prediction of burn depth and therefore can be a useful tool to help in guiding clinical decision and initial treatment of burn wounds.

Place, publisher, year, edition, pages
Oxford University Press, 2019
Burn depth, time-independent prediction, deep convolutional neural network, artificial intelligence
National Category
Surgery Medical Image Processing Other Clinical Medicine
urn:nbn:se:liu:diva-157386 (URN)10.1093/jbcr/irz103 (DOI)000495368300020 ()31187119 (PubMedID)

Funding agencies: Analytic Imaging Diagnostic Arena (AIDA)

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-11-27Bibliographically approved
Mirdell, R., Lemstra-Idsardi, A. N., Farnebo, S. & Tesselaar, E. (2018). Data on microcirculatory perfusion dips in the resting nail bed. Data in Brief, 21, 1232-1235
Open this publication in new window or tab >>Data on microcirculatory perfusion dips in the resting nail bed
2018 (English)In: Data in Brief, E-ISSN 2352-3409, Vol. 21, p. 1232-1235Article in journal (Refereed) Published
Abstract [en]

This article contains the raw data from the article entitled: "The presence of synchronized perfusion dips in the microcirculation of the resting nail bed" Mirdell et al. (in press). A laser speckle contrast imager (LSCI) was used to make a total of 21 recordings of the perfusion in the resting nail bed of 10 healthy test subjects. The first 10 recordings were acquired after 5?min of acclimatization. An additional 10 recordings were acquired in the same test subjects, after 20?min of acclimatization. In the last recording, a digital nerve block was applied to the left dig III. The data show the presence of highly irregular perfusion variations, a phenomenon we like to call perfusion dips. The data also show how the perfusion dips can be abolished through a digital nerve block. An algorithm for the quantification of the perfusion dips is included in the data.

Place, publisher, year, edition, pages
Elsevier, 2018
laser speckle contrast imaging; microcirculation; nail bed; perfusion
National Category
Bioinformatics and Systems Biology
urn:nbn:se:liu:diva-156038 (URN)10.1016/j.dib.2018.10.077 (DOI)30456238 (PubMedID)
Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-04-02
Zötterman, J., Mirdell, R., Horsten, S., Farnebo, S. & Tesselaar, E. (2017). Methodological concerns with laser speckle contrast imaging in clinical evaluation of microcirculation. PLoS ONE, 12(3), Article ID e0174703.
Open this publication in new window or tab >>Methodological concerns with laser speckle contrast imaging in clinical evaluation of microcirculation
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2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 3, article id e0174703Article in journal (Refereed) Published
Abstract [en]

Background Laser Speckle Contrast Imaging (LSCI) is a non-invasive and fast technique for measuring microvascular blood flow that recently has found clinical use for burn assessment and evaluation of flaps. Tissue motion caused by for example breathing or patient movements may however affect the measurements in these clinical applications, as may distance between the camera and the skin and tissue curvature. Therefore, the aims of this study were to investigate the effect of frame rate, number of frames/image, movement of the tissue, measuring distance and tissue curvature on the measured perfusion. Methods Methyl nicotinate-induced vasodilation in the forearm skin was measured using LSCI during controlled motion at different speeds, using different combinations of frame rate and number of frames/image, and at varying camera angles and distances. Experiments were made on healthy volunteers and on a cloth soaked in a colloidal suspension of polystyrene microspheres. Results Measured perfusion increased with tissue motion speed. The relation was independent of the absolute perfusion in the skin and of frame rate and number of frames/image. The measured perfusion decreased with increasing angles (16% at 60, p = 0.01). Measured perfusion did not vary significantly between measurement distances from 15 to 40 cm (p = 0.77, %CV 0.9%). Conclusion Tissue motion increases and measurement angles beyond 45 decrease the measured perfusion in LSCI. These findings have to be taken into account when LSCI is used to assess moving or curved tissue surfaces, which is common in clinical applications.

Place, publisher, year, edition, pages
National Category
Radiology, Nuclear Medicine and Medical Imaging
urn:nbn:se:liu:diva-137098 (URN)10.1371/journal.pone.0174703 (DOI)000399174800074 ()28358906 (PubMedID)

Funding Agencies|ALF grants, Region Ostergotland

Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2018-05-02

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