Assessment Of Diagnostic Accuracy Using A Digital Camera For Teledermatology

Elizabeth Krupinski, PhD Ben LeSueur, BS Lansing Ellsworth, MD Norman Levine, MD Ronald Hansen, MD Nancy Silvis, MD Peter Sarantopoulos, BS Pamela Hite, MD, MBA James Wurzel, BS Ronald Weinstein, MD Ana Marie Lopez, MD, MPH

Patients’ Opinions* 24% satisfied by care from non-dermatologist 89% satisfied by care from a dermatologist 6% believe a generalist can treat their skin disease 87% say access to dermatologist very important to their health care * Owen SA, Maeyens E, Weary PE. Patients’ opinions regarding direct access to dermatologic specialty care. JAAD 1997;36:

Goal The goal of this study was to compare diagnostic accuracy of a dermatologic diagnosis based on in-person examination compared to diagnosis with still photo images acquired with a digital camera and displayed on a CRT monitor.

Rationale Real-time video conferencing technologies may not be available or may be too costly for some rural sites. Store-forward technologies may be more appropriate, and should be tested before they are used clinically.

Subjects & Readers 308 consecutive patients referred for specialty consultation by PCP or general dermatologist to the Dermatology Clinic at the University of Arizona Health Sciences Center 104 of these cases were ultimately biopsied 3 board-certified specialty dermatologists

Exams Each dermatologist examined approximately 1/3 of the patients in person at the AHSC clinic Rendered either a single diagnosis (75% of the cases, n = 230) or 2 or 3 differential diagnoses (25% of the cases, n = 78) Up to 5 photos of the lesion ROIs were taken with a digital camera by 4 medical students trained in the use of the camera Global and close-up shots

The Digital Camera Canon PowerShot600 CCD image sensor 832 x 608 pixels 24-bit color resolution f/2.5 lens Built-in flash 150 kB file size

The Display Gateway 2000 computer Gateway CrystalScan color monitor: 1024 x 768 PhotoImpact Album v 3.0 display software Brief patient history in each case folder Randomized case presentation

Procedure Approximately 2 months after in-person exams, digital images were examined Same 3 dermatologists examined all 308 cases Single most likely diagnosis rendered Decision confidence: very definite, definite, probable, possible Rate image sharpness & color: excellent, good, fair, poor Viewing time recorded

Analyses In-person diagnosis = truth Correct match = digital diagnosis matches one of the differential possibilities listed during in- person Incorrect mismatch = digital diagnosis does not match any of the in-person differentials For biopsy analyses, biopsy = truth

Types of Cases Clinical Diagnosis Number of Cases Malignant or Premalignant91 Benign Proliferations74 Eczema/Dermatitis36 Pigmented Lesions32 Infections/Infestations20 Papulosquamous Disorders12 Urticarial & Allergic 5 Collagen/Vascular 1 Miscellaneous37

Biopsied Lesions Lesion Type Number Percent Infection/Infestation 3 3% Pigmented Lesions 26 25% Malignant/Premalignant 49 47% Dermatitis/Eczema 4 4% Benign Proliferations 12 11% Miscellaneous 10 10%

Diagnostic Accuracy F = 0.011, df = 2, p = no differences in accuracy between dermatologists Reader

Decision Confidence Reader

Observer Variation Intra-Observer Variation –Reader 1: 90% agreement (n = 104 cases) –Reader 2: 85% agreement (n = 102 cases) –Reader 3: 76% agreement (n = 102 cases) Inter-Observer Variation –Reader 1 vs 2: kappa = 0.82 –Reader 1 vs 3: kappa = 0.81 –Reader 2 vs 3: kappa = 0.80

Correct Decisions Biopsy Cases In-Person Photo vs Photo vs Reader vs BiopsyBiopsy In-Person 1 80% 78% 87% 2 97% 76% 79% 3 90% 73% 85% Mean 89% 76% 84%

Biopsy vs In-Person Mismatches

Image Quality Reader

Correlations Color & sharpness: r = 0.73 Color & Decision Confidence: r = 0.48 Sharpness & Decision Confidence: r = 0.47 Decision confidence was not affected significantly by overall quality of the images

Viewing Time Reader

Correlations View time vs color rating: r = 0.35 View time vs sharpness rating: r = 0.24 View time vs accuracy: r = 0.21 View time vs confidence: r = 0.54 View time vs single/multiple diagnoses: r = 0.15

Conclusions Digital photography can be used to acquire dermatology images for telediagnosis Image quality is overall excellent to good Diagnostic accuracy and confidence are high Digital image diagnoses compare favorably with in-person diagnoses and with biopsy results