Postinterventional MRI findings following MRI-guided laser ablation of osteoid osteoma.
OBJECTIVE
To evaluate postinterventional magnetic resonance imaging (MRI) characteristics following MRI-guided laser ablation of osteoid osteoma (OO).


METHODS
35 patients treated with MRI-guided laser ablation underwent follow-up MRI immediately after the procedure, after 3, 6, 12, 24, 36, and up to 48 months. The imaging protocol included multiplanar fat-saturated T2w TSE, unenhanced and contrast-enhanced T1w SE, and subtraction images. MR images were reviewed regarding the appearance and size of treated areas, and presence of periablation bone and soft tissue changes. Imaging was correlated with clinical status.


RESULTS
Mean follow-up time was 13.6 months. 28/35 patients (80%) showed a postinterventional "target-sign" appearance consisting of a fibrovascular rim zone and a necrotic core area. After an initial increase in total lesion diameter after 3 months, a subsequent progressive inward remodeling process of the zonal compartments was observed for up to 24 months. Periablation bone and soft tissue changes showed a constant decrease over time. MR findings correlated well with the clinical status. Clinical success was achieved in 32/35 (91%).


CONCLUSIONS
Evaluation of long-term follow-up MRI after laser ablation of OO identified typical postinterventional changes and thus may contribute to the interpretation of therapeutic success and residual or recurrent OO in suspected cases.
Department of Radiology, Charité, Humboldt University, Berlin, Germany. Electronic address: simon.fuchs@charite.de.
S
S
Fuchs
Department of Radiology, Charité, Humboldt University, Berlin, Germany.
B
B
Gebauer
Department of Radiology, Charité, Humboldt University, Berlin, Germany.
L
L
Stelter
Department of Radiology, Charité, Humboldt University, Berlin, Germany.
M L
ML
Schäfer
Department of Radiology, Charité, Humboldt University, Berlin, Germany.
D M
DM
Renz
Center for Musculoskeletal Surgery, Charité, Humboldt University, Berlin, Germany.
I
I
Melcher
Center for Musculoskeletal Surgery, Charité, Humboldt University, Berlin, Germany.
K
K
Schaser
Department of Radiology, Charité, Humboldt University, Berlin, Germany.
B
B
Hamm
Department of Radiology, Charité, Humboldt University, Berlin, Germany.
F
F
Streitparth
D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000473:pathology* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010017:Osteoma, Osteoid / Q000473:pathology* / Q000601:surgery*; D011182:Postoperative Care / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
MRI characteristics; MRI guidance; Muskuloskeletal; Osteoid osteoma; Thermal ablation