In vivo Reflectance Confocal Microscopy
In order to define a glossary of descriptors in melanocytic tumors, a list of parameters has been elaborated based on a critical review of the scientific literature. Independent investigators are invited to: 1) visualize the on-line tutorial describing the parameters, 2) evaluate a set of training images with real time feedback, and 3) access the evaluation area with the actual study images.
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Study design

Elaboration of a glossary of descriptors in melanocytic tumors

Based on a critical review of the scientific literature, a list of parameters has been elaborated.

A World Wide Web-based tutorial is provided to describe the unifying concept of confocal microscopy with complete definitions of the parameters and example images. A training set with 45 images will be subsequently available for the refinement and final elaboration of the list. Tutorial and training sets are based on the images previously employed for the study by Pellacani et al. (J Am Acad Dermatol 2005; 53:979-85).

Study data set

Images include both benign and malignant melanocytic lesions, acquired at three different depth levels, corresponding to the superficial epidermis, the dermal epidermal junction and the papillary dermis.

The test set will include images from consecutive original cases of melanocytic lesions excised with histopathological confirmation.

Preparation of the test set will consist in the selection of at least 1 image acquired at the superficial epidermis, 1 at dermal epidermal junction and 1 at papillary dermis level each case, considered representative of the lesion. From each tumour no more than 3 images per layer will be included. The total number of cases depend on the representation of the studied parameters in a sufficient number of cases for statistical analyses. The final study data set includes 90 images per level.

Evaluation of cases

The study is entirely conducted on-line, by means of dedicated web pages with username and password restricted access.

Independent investigators are invited to visualize the tutorial and to test themselves evaluating the training set images filling in the appropriate on-line electronic sheet. Immediately after submission of the completed form, the participants received the set of confocal microscopy criteria of that case. This real-time feedback is designed to assist the participants in mastering the criteria.

After the completion of the training set evaluations, the investigators will be allowed to access the test set images. The same electronic data sheets will be used with feedback no longer provided. Participants are permitted to evaluate only 1 image at a time, and each case have to be submitted as soon as it is completed. Each participant will be given 2 months (up to the end of December 2006) to complete the evaluation of the images of the test set.

To test for intraobserver agreement, 30 images will be randomly selected from the test set and included for re-examination; thus, each participant will perform 300 test evaluations. Tutorial and training set databases will be accessible in any time during the test set evaluation, whereas a test set analyzed image will not be further accessible until the end of the study.

Analysis of the results

For statistical analysis the SPSS statistical package (release 10.0.06, 1999; SPSS Inc., Chicago, Ill.) and the Stata statistical software (release 7.0. 1997; College Station, TX: Stata Corporation) will be employed.

The interobserver reproducibility among the observers will be assessed to calculate the kappa statistics for multiple ratings. The intraobserver reproducibility will be assessed on a subset of 10 images per depth level, randomly selected from the test set and resubmitted to each study participant. Cohen's kappa index for agreement will be calculated for each descriptor. Kappa values range between 1 and 0. A kappa value of 1.0 indicates full agreement beyond chance, values greater than 0.70 are generally considered excellent, values less than 0.40 poor and values between 0.40 and 0.70 fair to good.

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 All images are propriety of G. Pellacani and protected by copyright. Reproduction is not permitted without permission.