Cantwell Colin P, Kerr Jennifer, O'Byrne John, Eustace Stephen
Department of Radiology, Mater Misericordiae University Hospital, Eccles St., Dublin 7, Ireland.
AJR Am J Roentgenol. 2006 May;186(5):1220-7. doi: 10.2214/AJR.05.0149.
The purposes of our study were to determine the temporal changes in MR signal in bone after radiofrequency ablation of osteoid osteoma and the size of the zone of marrow signal change produced by the radiofrequency technique and to compare the size of the zone with published data for radiofrequency ablation with manual-control protocols.
Radiofrequency ablation was performed in 10 patients with a clinical and radiologic diagnosis of osteoid osteoma. A cooled radiofrequency probe was inserted in the nidus. Twelve minutes of radiofrequency energy was applied from a 200-W radiofrequency generator in an impedance-control setting. MRI with multiplanar turbo spin-echo T1-weighted and STIR sequences was performed at 1, 7, and 28 days after the procedure in seven patients. The three remaining patients had follow-up imaging at 28 days only. The images were reviewed by two radiologists who categorized the imaging features and measured the marrow zone of signal alteration when visible. The size of the zone of marrow signal change produced by the radiofrequency technique was compared with published data for radiofrequency ablation with manual-control protocols.
A 1-mm band of homogeneous altered marrow signal distributed symmetrically parallel to the entire probe tract was seen earliest, at 1 day, in the femoral neck lesion treated with the 2-cm probe. The band was low signal on the T1 sequence and high signal on the STIR sequence, and the diameter of the zone was 27 mm. By 7 days, five of the seven treated bones showed a band of marrow signal alteration. By 28 days, all 10 treated bones had a band of marrow signal alteration. The interband distance at 90 degrees to the probe measured on STIR images at 28 days was a mean of 20.9 mm (confidence interval, 16.1-25.7 mm [p < 0.05]; range +/- measurement error, 10.5-35 +/- 1.64 mm) with a 1-cm probe and 30.5 mm (measurement error, +/- 0.78 mm) on T1 images without contrast material when a 2-cm exposed-tip probe was used. Higher-output generators with impedance-control software and internally cooled radiofrequency probes with longer exposed tips produce larger zones of marrow signal change than expected with manual-control protocols.
MRI allows detection of temporal marrow signal change after radiofrequency ablation. The marrow signal change with a high-energy delivery protocol is larger than manual-control protocols.
我们研究的目的是确定骨样骨瘤射频消融术后骨内磁共振信号随时间的变化以及射频技术产生的骨髓信号改变区域的大小，并将该区域大小与已发表的采用手动控制方案的射频消融数据进行比较。
对10例临床及影像学诊断为骨样骨瘤的患者进行射频消融。将冷却的射频探头插入瘤巢。在阻抗控制设置下，使用200W射频发生器施加12分钟的射频能量。7例患者在术后1天、7天和28天进行了多平面涡轮自旋回波T1加权和短T1反转恢复（STIR）序列的磁共振成像。其余3例患者仅在28天进行了随访成像。由两位放射科医生对图像进行评估，他们对成像特征进行分类，并在可见时测量骨髓信号改变区域。将射频技术产生的骨髓信号改变区域大小与已发表的采用手动控制方案的射频消融数据进行比较。
最早在术后1天，在使用2cm探头治疗的股骨颈病变中，可见一条1mm宽的均匀改变的骨髓信号带，与整个探头路径对称平行分布。该信号带在T1序列上呈低信号，在STIR序列上呈高信号，区域直径为27mm。到7天时，7例接受治疗的骨骼中有5例出现骨髓信号改变带。到28天时，所有10例接受治疗的骨骼均有骨髓信号改变带。在28天时，在STIR图像上测量的与探头呈90度的带间距离，使用1cm探头时平均为20.9mm（置信区间，16.1 - 25.7mm [p < 0.05]；范围±测量误差，10.5 - 35 ± 1.64mm），使用2cm裸露尖端探头时在无对比剂的T1图像上为30.5mm（测量误差，±0.78mm）。具有阻抗控制软件的高输出发生器和具有更长裸露尖端的内部冷却射频探头产生的骨髓信号改变区域比采用手动控制方案时预期的更大。
磁共振成像能够检测射频消融术后骨髓信号随时间的变化。采用高能量传递方案时的骨髓信号改变比手动控制方案更大。
