1. Use of the SIAscope as an aid to the diagnosis of pigmented skin lesions
Dolianitis C, Kelly J
Victorian Melanoma Service,
Alfred Hospital, Melbourne

2. SIAscope I skin imaging system
SIAscope II

3. Infrared and colour wavebands
SIAGRAPHS
SIA Algorithms
Infrared and colour wavebands
Sensor
This results in the skin we see – a complex composite view
SIA uses light
……..
Detects and makes quantitative measurements of structures
Presents as SIAgraphs

4. Based on physics of image formation
Optical model of skin
Based on physics of image formation
Diffusion
Stratum Corneum
Absorption
Epidermis
Forward scatter
Absorption
Papillary dermis
Backscatter
Forward scatter
Reticular dermis

5. Optical model of skin B G R Stratum Corneum Epidermis Papillary dermis
Incident light
Absorption
Forward scatter
Backscatter
Diffusion
Stratum Corneum
Epidermis
Papillary dermis
Reticular dermis

6. Optical model of skin B G R R Stratum Corneum B Epidermis G
Incident light
Stratum Corneum
Epidermis
Papillary dermis
Reticular dermis

7. Optical model of skin
Normal skin with no infiltration of pigment into the dermis, including black, sunburnt, white skin R
Haemoglobin
Melanin B G

8. Creating SIAgraphs
This calculation is performed for each of the 600,000 points in the viewfinder
The colour at each point corresponds to a concentration of the component viewed
This makes a concentration map across the skin
Colours intended to be intuitive

9. Melanin Darker brown = higher concentration of melanin
Lighter brown = less melanin

10. Melanin
High melanin concentration
Normal melanin concentration

11. Dermal Melanin
Melanin involvement in dermis

12. Dermal Melanin White = no dermal melanin
Green = slight dermal involvement
Blue = moderate dermal involvement
Red = high dermal involvement
Black = maximum measurable dermal involvement

13. Dermal Melanin No melanin in dermis Low melanin involvement
High melanin involvement

14. Collagen Normal skin – grey / green
High collagen concentration – white
E.g. fibrosis
Low collagen concentration – dark
“Holes” in the collagen

15. Collagen Low collagen concentration High collagen concentration
Normal collagen concentration

16. Blood Low blood concentration High blood concentration
Normal blood concentration

17. Dermatoscopy view
Melanoma exhibits suggestion of blue-grey veil, several colours
Benign naevus has two colours and no suspicious features for melanoma

18. Dermal melanin view White = no dermal melanin Colours indicate different depths
Melanoma exhibits dermal melanin
Benign lesion has no dermal melanin

19. Collagen view Whiter = more collagen
Melanoma has irregular fibrotic reaction, “increased collagen”
Lesions also assessed for “collagen holes”, areas of decreased or absent collagen
Benign lesion has regular collagen

20. 3D collagen view
Shows collagen concentration
Not available on Siascope version 1 used in Melbourne study
Melanoma has irregularities in the collagen concentration
Benign lesion has very smooth collagen concentration

21. SIAGRAPHS Left hand side always shows dermatoscopy image of lesion
Right hand side image shows SIAgraph of same area of skin
OR can view dermatoscopy and 5 SIAgraphs all at once

22. Dermal-epidermal junction
Select an area of the lesion on the dermatoscopy image
3D view of dermal-epidermal junction shown for that area
“irregularity / regularity” of dermal-epidermal can be assessed

28. Melbourne SIAscope study
to investigate the role of the Siascope in differentiating melanomas from non-melanomas
EXPERT SETTING
Includes 88 lesions excised on suspicion of melanoma after clinical and dermatoscopic assessment

29. ASSESSMENT of SIAgraphs
Total melanin , Asymmetry of pattern in 0, 1, 2 axes
Dermal melanin, presence and concentration
Collagen, increased, decreased, collagen hole
Blood, increased (erythematous blush), decreased (blood displacement), irregular vessels
Dermal-epidermal junction, regular / degree of irregularity

30. DIAGNOSIS ? melanoma
TOTAL 88
Melanomas 53
Dysplastic naevi Melanocytic naevi 9
Spitz / spindle cell naevi Basal cell carcinomas Lichenoid keratoses Seborrhoeic keratoses Solar keratoses Other 1

31. NUMBER and THICKNESS of Melanomas
LEVEL I MELANOMA Superficial spreading melanomas 16 Lentigo malignas LEVEL II MELANOMA Superficial spreading melanomas , 0.40, 0.45, 0.45, 0.45, 0.45, 0.60, 0.60, 0.62, 0.65   LEVEL III MELANOMA  Superficial spreading melanomas , 0.35, 0.55, 0.55, 0.70, 0.80, 0.85 Nodular melanomas , 1.75    LEVEL IV MELANOMAS Superficial spreading melanomas , 2.30, 2.70, 4.20   LEVEL V MELANOMAS Lentigo maligna melanoma

32. Melanomas 29 level I melanomas 24 invasive melanomas
mean thickness of 1.22mm
Median thickness 0.62 mm
Group of early melanomas
Median level
level I melanoma

33. Feature Sensitivity Specificity Erythematous blush 100% (94-100)
88 lesions excised on suspicion of melanoma: Sensitivity, Specificity (95% confidence intervals) FEATURES WITH HIGH SENSITIVITY
Feature
Sensitivity
Specificity
Erythematous blush
100% (94-100)
11% (5-19)
Total asymmetry
94% (87 – 98)
34% (24 – 45)

34. Feature Sensitivity Specificity Blood comma 30 % (21-41) 94% (87-98)
88 lesions excised on suspicion of melanoma: Sensitivity, Specificity (95% confidence intervals) FEATURES WITH HIGH SPECIFICITY
Feature
Sensitivity
Specificity
Blood comma
30 % (21-41)
94% (87-98)
Blood displacement
6% (2-13)
77% (67-85)
Collagen hole
21% (13-31)
74% (64-83)

35. Feature Sensitivity Specificity 75% (65-83) 80% (70-87) 91% (83-96)
88 lesions excised on suspicion of melanoma: Sensitivity, Specificity (95% confidence intervals) COMBINATION OF FEATURES needed to achieve good sensitivity / specificity
Feature
Sensitivity
Specificity
Erythematous blush and Total asymmetry without blood displacement with either of collagen hole, blood comma or irregular dermal epidermal junction
75%
(65-83)
80%
(70-87)
Erythematous blush and total asymmetry with any of dermal melanin, collagen holes, blood comma or irregular dermal epidermal junction
91%
(83-96)
49%
(38-60)

36. EXPERT SETTING 88 lesions excised on suspicion of melanoma
Significant differences found between melanomas and non-melanomas with Siascope using combination of features
These results are independent of history, clinical, dermatoscopy and photographic assessment
Combination of clinical and dermatoscopy with Siascope would be expected to improve results

37. The “less expert setting”
larger group of mainly pigmented skin lesions
88 lesions excised on suspicion of melanoma after clinical and dermatoscopic assessment
AND another 129 lesions
Total of 217 lesions

38. The “Less expert” setting Lesion Number
Total
217
Melanomas 53
Seborrhoeic keratoses 47
Dysplastic naevi 43
Compound / Junctional naevi 25
SCC 10
Haemangioma 7
Solar keratoses 5

39. The “less expert” setting FEATURES WITH HIGH SENSITIVITY
Specificity
Erythematous blush
100 %
24%
Total asymmetry
94%
50%

40. The “less expert” setting FEATURES WITH HIGH SPECIFICITY
Sensitivity
Specificity
Blood comma
30%
96%
Collagen hole
21%
87%
Blood displacement 6%
85%
Irregular dermal epidermal junction
55%
71%
Dermal melanin
57%
69%

41. The “less expert” setting COMBINATION OF FEATURES gave best sensitivity / specificity
Erythematous blush and total asymmetry with any of dermal melanin, collagen hole, blood comma or irregular dermal epidermal junction
91%
82%
Total asymmetry and erythematous blush with either collagen hole or blood comma or irregular dermal-epidermal junction
81%
88%

42. Comparison ‘expert’ to ‘less expert’ setting
EXPERT SETTING Sensitivity / Specificity
LESS EXPERT Sensitivity/ Specificity
Erythematous blush and Total asymmetry without blood displacement with either of collagen hole, blood comma or irregular dermal epidermal junction
75% / 80%
75% / 92%
Erythematous blush and total asymmetry with at least one of dermal melanin, collagen hole, blood comma or irregular dermal-epidermal junction
91% / 49%
91% / 82%

43. Comments Some features objective, e.g. dermal melanin
Some features subjective, e.g. irregularity of dermal epidermal junction
Experience with the technique may affect results
NOT an automated diagnosis
Need to assess the reliability of assessment by the same observer and reproducibility of results between different observers

44. Comments
Recall bias (one person collecting images, following up pathology results and doing analysis)
This study - retrospective analysis, needs to be repeated in a prospective fashion with observer blinded to histopathology results
Histopathological correlation of Siascope features
Comparison of features displayed by melanomas of different thickness / level of invasion

45. Conclusion
Results independent of history, clinical features and dermatoscopic features
Combination of Siascope features were found to have good sensitivity and specificity in the diagnosis of melanoma
Combination of Siascope assessment with clinical and/or dermatoscopic assessment would improve sensitivity and specificity
Image collection funded by Astron Clinica, Cambridge, UK