Quantitative Radiographic and Computed Tomography Assessment of Pediatric Aneurysmal Bone Cysts: Relative Transverse Expansion, Physeal Proximity, and Postoperative Outcomes

Pediatric aneurysmal bone cysts (ABCs) are locally aggressive lesions with variable postoperative behavior, and quantitative imaging markers associated with healing or recurrence remain limited. This exploratory, retrospective, single-center study evaluated whether the relative transverse cyst index (RTCI), lesion-to-physis distance, and mean intralesional computed tomography (CT) attenuation were associated with radiographic outcomes after surgery. Twenty-four children with biopsy-confirmed primary ABCs treated between 2017 and 2023 underwent blinded dual-observer measurement of lesion dimensions, involved-bone length, physeal distance, and CT attenuation; outcomes were classified as complete healing, recurrence, or stable partial residual disease. RTCI differed across outcome groups (0.069 ± 0.024, 0.126 ± 0.046, and 0.114 ± 0.0534, respectively; p = 0.019, false-discovery-rate-adjusted q = 0.045), as did lesion-to-physis distance (4.58 ± 3.64, 1.04 ± 1.09, and 1.26 ± 1.95 cm; p = 0.023, q = 0.045). Mean CT attenuation did not differ among groups (p = 0.843). Greater relative transverse expansion and closer physeal proximity were associated with less favorable radiographic outcomes. These hypothesis-generating findings require validation in larger multicenter cohorts.