Ultrashort Time-to-Echo Magnetic Resonance Imaging at 3 T for the Detection of Spondylolysis in Cadaveric Spines Comparison With CT
Ultrashort Time-to-Echo Magnetic Resonance Imaging at 3 T for the Detection of Spondylolysis in Cadaveric Spines Comparison With CT
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DOI：
10.1097/rli.0000000000000506
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发表时间：
2019-01-01
影响因子：
6.7
通讯作者：
Bae, Won C.
中科院分区：
文献类型：
--
作者：
Finkenstaedt, Tim;Siriwanarangsun, Palanan;Bae, Won C.
目的本研究的目的是比较常规、优化和超短回波时间（UTE）磁共振（MR）方案检测人体尸体模拟腰椎峡部裂的诊断性能和置信度。此外，我们试图证明UTE技术在有和没有椎弓峡部裂的受试者中的可行性。材料与方法4具46个椎弓峡部的人体腰椎标本，随机保留完整（n = 26）或接受实验性截骨（n = 20），使用显微外科锯模拟椎弓峡部裂。使用计算机断层扫描（CT）扫描沿着3“层”MR方案在3 T下对标本进行成像：第1层，常规腰椎MR方案;第2层，优化的常规方案，包括矢状倾斜扰相梯度回波和轴向倾斜T1和短tau反转恢复序列;第3层，矢状UTE MR序列。两名设盲阅片员使用4分量表（1 =肯定不存在椎弓峡部裂，2 =很可能不存在，3 =很可能存在，4 =肯定存在）对每个峡部的图像进行评价。对于每种成像方案，使用McNemar检验评估和比较诊断性能（灵敏度、特异性和受试者工作特征曲线下面积，使用手术截骨术作为参考）和置信度。此外，2名人类受试者用常规和UTE MR方案成像，以证明体内可行性。结果：Tier 1和Tier 2的诊断性能为中等，具有中等灵敏度（0.70至0.75）和高特异性（1.00）。相比之下，CT和Tier 3 UTE MR成像具有高灵敏度（1.00）和特异性（1.00）。CT或第3层的敏感性在统计学上大于第1层的敏感性（P = 0.041），与第2层的敏感性（P = 0.074）相比接近统计学显著性。与第1层（0.89，P = 0.037）或第2层（0.873，P = 0.024）的面积相比，CT和第3层（每个面积= 1.00）的受试者操作特征曲线下面积也显着更大。CT或Tier 3的诊断置信度远高于其他Tier：Tier 1和Tier 2的不确定（> 60%，P < 0.001）或错误解释（> 10%，P < 0.001）的百分比都很高，不像CT或Tier 3（0%不确定或错误解释）。初步的体内UTE图像清楚地显示了完整和断裂的峡部。结论我们的研究表明，使用单一矢状位UTE MR序列检测峡部骨折在性能和置信度上上级传统和优化的3 T MR协议，而与CT评估的结果相当。此外，我们还证明了UTE序列在患有和不患有椎弓峡部裂的受试者体内应用的可行性。
Objectives The objective of this study was to compare the diagnostic performance and confidence of conventional, optimized, and ultrashort time to echo (UTE) magnetic resonance (MR) protocols for detection of simulated lumbar spondylolysis in human cadavers. In addition, we sought to demonstrate the feasibility of the UTE technique in subjects with and without spondylolysis. Materials and Methods Four human lumbar spine specimens with 46 individual pars interarticularis were randomly left intact (n = 26) or received experimental osteotomy (n = 20) using a microsurgical saw to simulate spondylolysis. The specimens were imaged using a computed tomography (CT) scan along with 3 "Tiers" of MR protocols at 3 T: Tier 1, conventional lumbar MR protocol; Tier 2, optimized conventional protocol consisting of a sagittal oblique spoiled gradient recall echo and axial oblique T1 and short tau inversion recovery sequences; and Tier 3, a sagittal UTE MR sequence. Two blinded readers evaluated the images using a 4-point scale (1 = spondylolysis certainly absent, 2 = probably absent, 3 = probably present, 4 = certainly present) at each individual pars. For each imaging protocol, diagnostic performance (sensitivity, specificity, and area under the receiver operating characteristic curve, using the surgical osteotomy as the reference) and confidence were assessed and compared using the McNemar test. Furthermore, 2 human subjects were imaged with the conventional and UTE MR protocols to demonstrate feasibility in vivo. Results Diagnostic performance was moderate for Tiers 1 and 2, with a moderate sensitivity (0.70 to 0.75) and high (1.00) specificity. In contrast, CT and Tier 3 UTE MR imaging had both high sensitivity (1.00) and specificity (1.00). The sensitivities of CT or Tier 3 were statistically greater than Tier 1 sensitivity (P = 0.041) and neared statistical significance when compared with Tier 2 sensitivity (P = 0.074). Area under the receiver operating characteristic curve was also significantly greater for CT and Tier 3 (each area = 1.00), compared with the areas for Tier 1 (0.89, P = 0.037) or Tier 2 (0.873, P = 0.024). Diagnostic confidences of CT or Tier 3 were much greater than other Tiers: Both Tiers 1 and 2 had a large percentage of uncertain (>60%, P < 0.001) or wrong interpretations (>10%, P < 0.001), unlike CT or Tier 3 (0% uncertain or wrong interpretations). Preliminary in vivo UTE images clearly depicted intact and fractured pars. Conclusions Our study demonstrated that the detection of pars fractures using a single sagittal UTE MR sequence is superior in performance and confidence to conventional and optimized MR protocols at 3 T, whereas matching those from CT evaluation. Furthermore, we demonstrated the feasibility of in vivo application of the UTE sequence in subjects with and without spondylolysis.