Impact of Magnetic Resonance Imaging (MRI) Findings on Management of Symptomatic Patients Following Radiofrequency Ablation (RFA) of Osteoid Osteoma (OO)

Majid Maybody,Meier Hsu,Elena Kaye,Mohamed M Soliman,Ernesto G Santos Martin,Nicola Fabbri,Adrian Gonzalez-Aguirre,John H Healey,Chaya Moskowitz,Sinchun Hwang

doi:10.1007/s42399-020-00514-7

Majid Maybody, Meier Hsu + Show 8 more

Open Access

https://doi.org/10.1007/s42399-020-00514-7

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Abstract

The purpose of this study is to assess the impact of MRI findings on management of symptomatic patients following RFA of OO. Retrospective review of 43 patients with RFA for OO between June 2010 and June 2017 was performed. Patient, nidus, and ablation data were reviewed. Pre- and 6–8 weeks post-procedural MRI (n = 32) were compared for coverage of nidus by ablation zone, bone marrow edema, nidus hyperintensity, and other findings. Baseline pain levels and analgesic use were compared with post-procedural follow-up visit at 6–8 weeks. Three groups of clinical and MRI outcomes of complete (CR), partial (PR), and no response (NR) were defined. A weighted kappa statistic was used to assess for agreement. Clinical responses were CR in 34/43 (79.1%, 95% CI: 64.0–90.0%), PR in 8/43 (18.6%), and NR in 1/43 (2.3%) patients. All 19/32 patients with MRI CR experienced clinical CR. One patient with MRI NR had clinical NR. All 7/32 patients with clinical PR had MRI PR. All 4/43 complications were in MRI PR or NR groups. Substantial agreement was observed between MRI and clinical outcomes (kappa: 0.69, 95% CI: 0.45–0.95). MRI helped determine etiologies in all symptomatic patients and their management (n = 8). MRI is recommended for symptomatic patients after ablation.

Highlights

Osteoid osteoma (OO) accounts for 11% of all benign bone tumors affecting males twice than females
The purpose of this study is to evaluate the agreement of post-procedural MRI findings with clinical outcomes following ablation of OO for patients who remain symptomatic
The first imaging assessment of technical success was based on coverage of nidus by ablation zone on MRI obtained 6–8 weeks after ablation

Summary

Introduction

Osteoid osteoma (OO) accounts for 11% of all benign bone tumors affecting males twice than females. It predominantly affects patients in their first and second decades of life. It most commonly affects the diaphyseal or metaphyseal cortex of long bones, in the lower extremities. Osteoid osteoma is commonly diagnosed based on a combination of a characteristic history, physical examination, and imaging findings. Radiographs or computed tomography (CT) evidence of an intracortical nidus with perilesional cortical thickening or MRI findings of a hyperintense, enhancing nidus and extensive perilesional bone marrow edema on T2weighted sequence are highly suggestive of OO [2]. Multiple treatment modalities exist, including conservative management with chronic use of analgesics, surgical management with en bloc resection or curettage, and image-guided thermal ablation [1]

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