Yankelevitz D F, Henschke C I, Knapp P H, Nisce L, Yi Y, Cahill P
Department of Radiology, New York Hospital--Cornell University Medical College, NY 10021.
AJR Am J Roentgenol. 1991 Jul;157(1):87-92. doi: 10.2214/ajr.157.1.1904679.
Bone marrow suppression is often the limiting factor in the use of radiation therapy. In order to determine if MR imaging can be used to quantify bone marrow changes, we performed a serial prospective study of patients with lung cancer (six cases) and lymphoma (six cases). Quantitative and qualitative assessments of T1-weighted sagittal images, 750/33 (TR/TE), obtained at 0.6 T before, during, and after radiotherapy showed increased signal intensity in the radiated portions of the spine. These changes appeared as early as 2 weeks after the beginning of radiation, continued to increase until a maximum value was attained, and then persisted during the follow-up period of 2 years. A significantly higher (p less than .04) ratio of pretreatment to maximum posttreatment signal intensity was seen in patients with lymphoma than in those with lung cancer, and pretreatment values in patients with lymphoma were significantly lower (p less than .01). The lower pretreatment values found in the patients with lymphoma may have been due to the smaller amount of yellow marrow in these patients, who were significantly younger (33 vs 62 years). The higher ratio of pre- and posttreatment signal intensity may have been related to the larger amount of hematopoietic marrow available to undergo fatty replacement. The persistence of elevated signal intensity for as long as 2 years after radiation suggests an endpoint in the process of marrow conversion, but not reversal in the form of regeneration of hematopoietic bone marrow. Quantitative MR evaluation of bone marrow may be of considerable value as a noninvasive means of monitoring the effects of radiotherapy.
骨髓抑制常常是放射治疗应用中的限制因素。为了确定磁共振成像（MR成像）是否可用于量化骨髓变化，我们对肺癌患者（6例）和淋巴瘤患者（6例）进行了一项系列前瞻性研究。在放疗前、放疗期间及放疗后，于0.6T场强下获取矢状面T1加权图像（750/33，TR/TE），进行定量和定性评估，结果显示脊柱受照射部位的信号强度增加。这些变化在放疗开始后2周即出现，持续增加直至达到最大值，然后在2年的随访期内持续存在。淋巴瘤患者治疗前与治疗后最大信号强度的比值显著高于肺癌患者（p小于0.04），且淋巴瘤患者的治疗前值显著更低（p小于0.01）。淋巴瘤患者治疗前值较低可能是由于这些患者黄骨髓量较少，他们明显更年轻（33岁对62岁）。治疗前与治疗后信号强度的较高比值可能与可发生脂肪替代的造血骨髓量较大有关。放疗后长达2年信号强度持续升高表明骨髓转化过程存在一个终点，但并非以造血骨髓再生的形式逆转。骨髓的定量MR评估作为一种监测放疗效果的非侵入性手段可能具有相当大的价值。
