Dissecting the heterogeneity of craniofacial lesions in patients with fibrous dysplasia/McCune-Albright Syndrome.

Fibrous dysplasia/McCune-Albright Syndrome (FD/MAS) frequently involves the craniofacial skeleton. Craniofacial fibrous dysplasia lesions exhibit diverse imaging characteristics on multimodality evaluation, utilizing radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and 18F-sodium fluoride positron emission tomography (18F-NaF PET). A multimodal imaging classification of craniofacial fibrous dysplasia lesions may offer clinical insights into the types of lesions that are (1) prone to progression, (2) amenable to intervention (i.e., pharmacological or surgical), or (3) associated with symptoms such as pain. In this prospective, preliminary single site study of 15 patients with FD/MAS, the heterogeneity of craniofacial lesions (N = 35) was assessed using a combination of 18F-NaF PET, MRI, and CT. A k-means clustering algorithm was used to categorize lesions based on imaging characteristics. Clustering analysis revealed three types of lesion based on the magnitude of the regional 18F-NaF standardized uptake values (SUV), signal intensities on T1-weighted and fluid-sensitive sequences, and appearance on CT (lucent, sclerotic, and/or ground glass). This preliminary study provides a foundation for future longitudinal natural history or treatment studies, where the prognostic value of baseline craniofacial fibrous dysplasia imaging characteristics and clinical symptomatology can be further evaluated.

Accuracy of skeletal scintigraphy for the evaluation of mandibular growth disorders: a systematic review.

Bone scans, reflecting blood flow and metabolic activity in a region of interest, are frequently used to evaluate mandibular growth disorders. Increased uptake is a non-specific finding and can occur as a result of multiple causes. The correlation between radioactive tracer uptake and growth activity has not been consistently demonstrated. The aim of this study was to assess the accuracy of planar skeletal scintigraphy (SS), single-photon emission computed tomography (SPECT), and SPECT with computed tomography (CT) images (SPECT/CT) in detecting abnormal mandibular growth activity compared to clinical and radiographic/tomographic methods (reference standard) and histologic findings. A systematic review was conducted following the PRISMA guidelines. Sensitivity, specificity, and accuracy were calculated for planar SS, SPECT, and SPECT/CT. Compared to the reference standard, SPECT/CT had the best diagnostic accuracy (76.5% sensitivity, 90.4% specificity, 83.2% accuracy), followed by planar SS (81.8% sensitivity, 84.5% specificity, 83.0% accuracy) and SPECT (77.7% sensitivity, 72.4% specificity, 74.5% accuracy). The results of this study indicate that SPECT/CT has the best clinical correlation, but the certainty of the evidence is low. The differences in sensitivity and specificity between the three index tests were not clinically significant. The three tests can be useful, with only a small difference in their diagnostic value. Histopathology was found not to be satisfactory as a reference standard.