Inter- and Intra-rater Agreement of Dermatologic Ultrasound for the Diagnosis of Lobular and Septal Panniculitis

Objectives: Dermatologic ultrasound (US) may aid in the diagnosis and classification of panniculitis. The purpose of this study was to assess the capability of dermatologic US for subtyping mainly septal/lobular panniculitis.

Methods: A multicentric and prospective study of the inter- and intra-rater agreement of dermatologic US for subtyping panniculitis was conducted among 4 clinicians with experience in dermatologic US and a radiologist specialized in dermatologic US. Clinicians recruited patients and performed dermatologic US examinations of the most substantial lesion and punch biopsies. A histologic study was considered the reference standard. Then the images were blindly evaluated by all researchers. For intra- and inter-rater agreement, Cohen and Fleiss κ values were calculated.

Results: Sixty-four patients were included. The Cohen intra-rater κ was 0.74. Sensitivity and specificity for lobular panniculitis were 85.19 and 88.57, respectively. The Fleiss inter-rater κ was 0.47. Limitations of the study included the small number of patients and differences in evaluators and their dermatologic US equipment.

Conclusions: This study supports the use of US for diagnosing panniculitis. For subtyping panniculitis, the intra-rater correlation was good. Improvement of inter-rater agreement may depend on access to clinical information, dynamic images, a better definition of criteria, homogeneous configurations of the devices, and the expertise of dermatologic US operators.