Mehmet Ali KAPTAN, Berat ACU, Çiğdem ÖZTUNALI, Cüneyt ÇALIŞIR, Ulukan İNAN, Muzaffer BİLGİN

Correlation of 3-T MRI and CT ﬁndings with patient symptoms and treatment outcome in radiofrequency ablation of osteoid osteoma

Objective: The aim of this prospective study was to evaluate pre- and post-treatment MRI and CT ﬁndings of osteoid osteoma (OO) patients treated with radiofrequency thermo-ablation (RFTA) and to compare these ﬁndings with visual analog scale (VAS) scores. Methods: Sixteen patients (4 females and 12 males; mean age of 18.87 ± 8.75 years (range: 8e37)) with OO were examined with CTand MRI, at baseline and at an average of 3 months following the procedure. On pre- and post-procedural CT and MRIs, OO-related ﬁndings were recorded. Treatment success was evaluated with VAS scores. Results: Baseline VAS scores were 8 or 9 and follow-up scores were 0 or 1, indicating no early recurrences. Nidus diameters decreased signiﬁcantly after the procedure (p ¼ 0.027, p ¼ 0.002, and p ¼ 0.002; and p ¼ 0.001, p ¼ 0.001, p ¼ 0.001 for AP, ML and CC nidus diameters for CT and MRI, respectively). The mean nidus volume were signiﬁcantly decreased after the procedure (p ¼ 0.001, for CT and MRI). On post-procedural images, cortical thickening, the signal intensity and contrast enhancement of the nidus and the extent of periostitis were signiﬁcantly decreased (p ¼ 0.019, p ¼ 0.001, p ¼ 0.001 and p ¼ 0.034, respectively). There was no signiﬁcant change in nidus calciﬁcation, perinidal cortical and intramedullary sclerosis, periosteal reaction, bone deformity, bone marrow and soft tissue edema, joint effusion and synovitis after the procedure (p ¼ 0.253, p ¼ 0.062, p ¼ 0.245, p ¼ 1, p ¼ 1, p ¼ 0.429, p ¼ 0.371, p ¼ 0.625, p ¼ 1). Conclusion: Although the changes in imaging ﬁndings may be helpful in early follow-up of OO patients treated with RFTA, these changes alone cannot be used with accuracy in predicting treatment response. Level of Evidence: Level IV, Therapeutic Study.

___

Campanacci M. Bone and Soft Tissue Tumors: Clinical Features, Imaging, Pathology and Treatment. 2nd ed. Vienna: Austria: Springer Science & Business Media; 1999.

Pratali R, Zuiani G, Inada M, et al. Open resection of osteoid osteoma guided by a gamma-probe. Int Orthop. 2009;33:219e223.

Kransdorf MJ, Stull MA, Gilkey FW, Moser Jr RP. Osteoid osteoma. Radiographics. 1991;11:671e696.

Cohen MD, Harrington TM, Ginsburg WW. Osteoid osteoma: 95 cases and a review of the literature. Semin Arthritis Rheum. 1983;12:265e281.

Clark T, Sabharwal T. Interventional Radiology Techniques in Ablation. 1st ed. London: England: Springer Science & Business Media; 2013.

Lee MH, Ahn JM, Chung HW, et al. Osteoid osteoma treated with percutaneous radiofrequency ablation: MR imaging follow-up. Eur J Radiol. 2007;64: 309e314.

Ronkainen J, Blanco Sequeiros R, Tervonen O. Cost comparison of low-ﬁeld (0.23 T) MRI-guided laser ablation and surgery in the treatment of osteoid osteoma. Eur Radiol. 2006;16:2858e2865.

Teixeira PA, Chanson A, Beaumont M, et al. Dynamic MR imaging of osteoid osteomas: correlation of semiquantitative and quantitative perfusion parameters with patient symptoms and treatment outcome. Eur Radiol. 2013;23: 2602e2611.

Liu PT, Chivers FS, Roberts CC, Schultz CJ, Beauchamp CP. Imaging of osteoid osteoma with dynamic gadolinium-enhanced MR imaging. Radiology. 2003;227:691e700.

Vanderschueren GM, Taminiau AH, Obermann WR, van den BergHuysmans AA, Bloem JL, van Erkel AR. The healing pattern of osteoid osteomas on computed tomography and magnetic resonance imaging after thermocoagulation. Skelet Radiol. 2007;36:813e821.

Martel J, Bueno A, Ortiz E. Percutaneous radiofrequency treatment of osteoid osteoma using cool-tip electrodes. Eur J Radiol. 2005;56:403e408.

Rehnitz C, Sprengel SD, Lehner B, et al. CT-guided radiofrequency ablation of osteoid osteoma: correlation of clinical outcome and imaging features. Diagn Interv Radiol. 2013;19:330e339.

Kawaguchi Y, Sato C, Hasegawa T, Oka S, Kuwahara H, Norimatsu H. Intraarticular osteoid osteoma associated with synovitis: a possible role of cyclooxygenase-2 expression by osteoblasts in the nidus. Mod Pathol. 2000;13: 1086e1091.

Lee JM, Choi SH, Park HS, et al. Radiofrequency thermal ablation in canine femur: evaluation of coagulation necrosis reproducibility and MRIhistopathologic correlation. Am J Roentgenol. 2005;185:661e667.