Delineation of Skin Strata in
Reflectance Confocal Microscopy
Images With Recurrent
Convolutional Networks
Alican Bozkurt*, Trevor Gale*, Kivanc Kose, Christi Alessi-Fox, Dana
Brooks, Milind Rajadhyaksha, Jennifer Dy
Preliminary
Dermatology
Deep learning
Reflectance
Confocal Microscopy
This
Work
The Skin & Dermal-Epidermal Junction (DEJ)
• Outer shell of the body
• Exposed to outside effects, e.g. sun,
chemicals, etc...
• Skin cancer is the most common
cancer in USA
• Melanoma is among the deadliest.
https://openi.nlm.nih.gov/detailedresult.php?img=PMC2914370_cde0002-0103-f03&req=4
https://www.cancer.org/cancer/melanoma-skin-cancer/detection-diagnosis-staging/survival-rates-for-melanoma-skin-cancer-by-stage.html
• Most skin cancers emerge from
dermal-epidermal junction (basal
layer)
• Early detection is important
• Early stage→5 Year survival 98%
• Late stage → 5 year Survival 18%
Lesions overall
body
Clinically
Suspicious
Dermoscopically
Suspicious
Cancer or
Not
Current Practice
Lesions overall
body
Clinical
Examination
Clinically
Suspicious
Dermoscopically
Suspicious
Biopsy
Cancer or
Not
Current Practice
Lesions overall
body
Clinical
Examination
Clinically
Suspicious
Dermoscopy
Dermoscopically
Suspicious
Cancer or
Not
Current Practice
Lesions overall
body
Clinical
Examination
Clinically
Suspicious
Dermoscopy
Dermoscopically
Suspicious
Biopsy
Cancer or
Not
Current Practice
Current Practice - Biopsy
• Invasive - > Scarring
• Incisional biopsies may miss
• %80 biopsies turn out to be benign
Lesions overall
body
Clinical
Examination
Clinically
Suspicious
Dermoscopy
Dermoscopically
Suspicious
Biopsy
Cancer or
Not
Current Practice
• Invasive - > Scarring
• Incisional biopsies may miss
• %80 biopsies turn out to be benign
Lesions overall
body
Clinical
Examination
Clinically Suspicious
Dermoscopy
Dermoscopically
Suspicious
Reflectance
Confocal
Microscopy
RCM
Suspicious
Biopsy
Cancer or
Not
Current Practice
Lesions overall
body
Clinical
Examination
Clinically Suspicious
Dermoscopy
Dermoscopically
Suspicious
Reflectance
Confocal
Microscopy
RCM
Suspicious
Biopsy
Cancer or
Not
Current Practice
• Non-invasive-> No scarring
• RCM Improves “Number Need to Treat” by 2x
(But in the hands of a trained clinician)
Reflectance Confocal Microscopy
1k x 1k pixels= 0.5mm x 0.5mm
12k x 12k pixels= 6mm x 6mm
0.2mm
Skin Imaging: Biopsy Vs RCM
https://openi.nlm.nih.gov/detailedresult.php?img=PMC2914370_cde0002-0103-f03&req=4
Epidermis
Dermis
Skin Imaging: Biopsy Vs RCM
https://openi.nlm.nih.gov/detailedresult.php?img=PMC2914370_cde0002-0103-f03&req=4
Data & Objective
• Given a stack, label each image Epidermis, DEJ, or Dermis
Classification using single images
• Classify images independently (not using
sequence information)
• Inception v3 (Szegedy et al.,2015)
• Trained from scratch
• Other methods
• Hames et al. (2016): BoW + linear SVM
• Kaur et al. (2016): MR8 filters + histogram +
MLP
Hames, Samuel C., et al. "Automated segmentation of skin strata in reflectance confocal microscopy depth stacks." PloS one 11.4 (2016): e0153208.
Kaur, Parneet, et al. "Hybrid deep learning for Reflectance Confocal Microscopy skin images." Pattern Recognition (ICPR), 2016 23rd International Conference on. IEEE, 2016.
Results
• Non-sequential methods can’t capture structure of the problem
• Epidermis → DEJ → Dermis
Accuracy (%)
Error types
Total #
ErrorEpidermis
→ Dermis
DEJ →
Epidermis
Dermis →
Epidermis
Dermis →
DEJ
Inception-v3 84.87 3 25 8 32 68
Hames et al. 84.48 14 59 11 56 140
Kaur et al. 64.33 32 255 16 99 402
Results
Incorperating sequential information- RNN
• Recurrent:
𝑠𝑡 = 𝑓 𝑥 𝑡, 𝑠𝑡−1
• LSTM (Hochreiter &
Schmidhuber, 1997)
• GRU (Chung et al., 2014)
Full sequence RCN
Full sequence RCN
Results
• Sequential methods improve performance drastically
• Is it overkill?
Accuracy (%)
Error types
Total #
ErrorEpidermis
→ Dermis
DEJ →
Epidermis
Dermis →
Epidermis
Dermis →
DEJ
Full seq. RCN 87.97 0 4 0 3 7
Inception-v3 84.87 3 25 8 32 68
Hames et al. 84.48 14 59 11 56 140
Kaur et al. 64.33 32 255 16 99 402
Partial Sequence RCN
• Motivation: Experts do not look at all the images in a stack while labeling an image
Results
• Sequential methods improve performance drastically
Accuracy (%)
Error types
Total #
ErrorEpidermis
→ Dermis
DEJ →
Epidermis
Dermis →
Epidermis
Dermis →
DEJ
Full seq. RCN 87.97 0 4 0 3 7
Par. Seq. RCN 87.52 3 10 5 5 23
Inception-v3 84.87 3 25 8 32 68
Hames et al. 84.48 14 59 11 56 140
Kaur et al. 64.33 32 255 16 99 402
Results
Conclusions
• RCM as beneficial screening
before biopsy
• Convolutional + recurrent units for
highly structured problem
• Deep learning based methods
beat hand-tuned features
• Adding sequential information
improves performance
• RCNs beat vanilla CNNs
• Using only 3 images gives similar
accuracy to best model
Acknowledgements
• This work was supported in part by the National Cancer Institute
(NCI) under grants R01CA156773 and R01CA199673, the National
Institute of Biomedical Imaging and Bioengineering’s (NIBIB) Image
Guided Interventions Program under grant R01EB012466, the NCI
Core Center grant P30CA008748, and NIBIB grant R01EB020029.

Delineation of Skin Strata in Reflectance Confocal Microscopy Images with Recurrent Convolutional Networks

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