Background/Purpose:

Linear scleroderma of the face (LSF) is a very disabling condition and, to date, standardized and validated methods for assessing and monitoring the disease progression are lacking. The Cone Beam Computed Tomography (CBCT) is an imaging technique with good sensitivity for both soft and bony tissues, fast to be performed with no need for patient sedation. Of interest, the radiation exposure is 50 times lower than a traditional CT scan, being the ideal technique for a repeated use. We investigated whether CBCT may represent a reliable tool for assessing patients with LSF and monitoring their course over time.

Methods: Ten consecutive patients with LSF, aged 3-21 years, and 5 age-matched healthy controls underwent CBCT assessment. The transverse sections of CBCT scan, in digital format, were analyzed according with three arbitrarily selected anatomic levels: mandibular condyle (MC), floor of the maxillary sinus (MS) and mandibular foramen (MF). Measurements of both affected and unaffected side of the face were made by a standardized methodology. From the intersection axes, an origin point was generated and from this one, 30° and 60° lines, crossing bony and soft structures, were drawn. For each given degree, the soft tissue thickness and the total thickness (bony and soft tissues) of the right and left side were calculated by using the software Onis 2.4 free edition. Twenty-four measures for each subject (two for each side, right and left, of the three transverse sections) were therefore evaluated. Five raters, all physicians, after a two-hour training session, evaluated LSF patients’ and controls’ CBCTs twice and blindly one from the other. The intra-rater reliability was assessed by the repeatability coefficient and the inter-rater reliability by the Intraclass Correlation Coefficient (ICC) and interpreted as follows: ICC values range 0.75-1 excellent reliability, 0.4-0.74 good reliability, <0.4 poor reliability.

Results: CBCT was fast and well tolerated by the patients even the youngest. The intra-rater concordance resulted optimal as the repeatability coefficient ranged between 0.77 and 0.99. The inter-rater concordance for the total thickness, among the assessors, was also excellent with mean ICC value of 0.75 (SD 0.16) for patients and 0.89 (SD 0.09) for controls. The mean ICC for the soft tissue thickness was 0.49 (SD 0.24) for patients and 0.66 (SD 0.28) for controls, respectively. 58.3% of the measurements for patients and 91.2% of those for controls showed excellent ICC results (> 0.75). The best performances were obtained at the level of the MF and MC sections.

Conclusion: CBCT is a reliable method to assess and monitor skin and bone changes in patients with LSF. It is a fast, reproducible and reasonably safe technique. A prospective validation to confirm its relevance in evaluating the disease progression is ongoing.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cone-beam-computed-tomography-for-the-assessment-of-linear-scleroderma-of-the-face/