University Health Network, Joint Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
Translational Medicine Program, The Hospital for Sick Children, Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
AJR Am J Roentgenol. 2020 Apr;214(4):817-824. doi: 10.2214/AJR.19.22023. Epub 2020 Feb 11.
The purpose of this study is to evaluate the diagnostic value of in vivo MR spectroscopy (MRS) with semilocalization by adiabatic selective refocusing (semi-LASER MRS) in differentiating clear cell renal cell carcinoma (RCC) from the non-clear cell subtype. Sixteen patients with biopsy-proven RCC or masses highly suspicious for RCC were prospectively recruited to participate in the study. Single-voxel H spectra were acquired using a 3-T MRI system, with a semi-LASER sequence acquired for renal tumors in 14 patients and for healthy renal tissue (control tissue) in 12 patients. Offline processing of the MR spectra was performed. MRI and spectra analysis were performed independently by radiologists who were blinded to the reference histopathologic findings. Semi-LASER MRS was diagnostic for nine of 11 patients (82%) with histopathologically proven clear cell RCC, showing a strong lipid peak in seven patients and a weaker lipid resonance in two others, whereas control spectra showed weakly positive findings in only one patient. MRS findings were negative for lipid resonance in two of three patients (67%) with non-clear cell tumors and were weakly positive in another patient. Semi-LASER MRS had a high sensitivity and positive predictive value of 82% and 90%, respectively, in addition to a specificity of 67%, a negative predictive value of 50%, and overall accuracy of 79% for the detection of clear cell RCC. Lipid resonance was detected by MRS for four of six clear cell RCCs with no intravoxel fat on chemical-shift MRI. The preliminary results of the present study show that semi-LASER MRS is promising for the noninvasive discrimination of clear cell RCC from non-clear cell RCC on the basis of detection of lipid resonance and that it provides an incremental yield compared with chemical-shift MRI.
本研究旨在评估半局部化（半 LASER MRS）活体磁共振波谱（MRS）在鉴别透明细胞肾细胞癌（RCC）与非透明细胞亚型中的诊断价值。 本研究前瞻性招募了 16 名经活检证实的 RCC 或高度疑似 RCC 的患者。 使用 3T MRI 系统采集单体素 H 谱，14 名患者采集半 LASER 序列的肾肿瘤，12 名患者采集健康肾组织（对照组织）的半 LASER 序列。对 MR 谱进行离线处理。MRI 和光谱分析由放射科医生独立进行，他们对参考组织病理学发现不知情。 半 LASER MRS 对 11 名经组织病理学证实为透明细胞 RCC 的患者中的 9 名（82%）具有诊断价值，其中 7 名患者显示强烈的脂质峰，另外 2 名患者显示较弱的脂质共振，而对照光谱仅在 1 名患者中显示弱阳性。非透明细胞肿瘤的 3 名患者中的 2 名（67%）的 MRS 结果为脂质共振阴性，另一名患者的 MRS 结果为弱阳性。半 LASER MRS 在检测透明细胞 RCC 时具有 82%的高敏感性和 90%的阳性预测值，特异性为 67%，阴性预测值为 50%，总体准确率为 79%。MRS 检测到 6 个透明细胞 RCC 中有 4 个没有化学位移 MRI 上的病灶内脂肪，在化学位移 MRI 上无病灶内脂肪。 本研究的初步结果表明，半 LASER MRS 有望通过检测脂质共振对透明细胞 RCC 与非透明细胞 RCC 进行非侵入性鉴别，并且与化学位移 MRI 相比具有额外的收益。
