Gayed Isis W, Liu H Helen, Yusuf Syed Wamique, Komaki Ritusko, Wei Xiong, Wang Xuanmin, Chang Joe Y, Swafford Joseph, Broemeling Lyle, Liao Zhongxing
Department of Nuclear Medicine, University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
J Nucl Med. 2006 Nov;47(11):1756-62.
The detection of myocardial perfusion abnormalities after radiation therapy (RT) has been investigated previously in patients with lymphoma and breast cancer. However, the prevalence and association of such abnormalities with RT in esophageal cancer patients have not been investigated previously.
The prevalence of myocardial perfusion abnormalities detected using gated myocardial perfusion imaging (GMPI) in patients with esophageal cancer after RT (RT group) was compared with that in patients with esophageal cancer who did not undergo RT (NRT group). The patients' data were extracted from a prospectively collected database. The results of GMPI that were read by multiple readers were tested further by an expert reader who was unaware of the patients' clinical information. This reader's findings were correlated with the different RT isodose lines as seen in the CT for RT planning. Isodose lines containing the affected segments in GMPI as well as the rest of the left ventricle were recorded. Additionally, information with regard to the mean radiation dose to the heart for each patient was collected. An overall, mean radiation dose to the heart in patients with abnormal GMPI studies was compared with that in patients with normal GMPI studies.
Fifty-one patients were included, 26 in the RT group and 25 in the NRT group. The mean and median interval between RT and GMPI was 7.5 and 3.0 mo, respectively. We identified myocardial perfusion defects in 14 patients (54%) in the RT group and in 4 patients (16%) in the NRT group. Eleven patients (42%) in the RT group had mild inferior wall ischemia versus only 1 patient (4%) in the NRT group (P = 0.001). All of the patients with inferior wall ischemia had distal esophageal cancer. The remaining 12 patients in the RT group and 21 patients in the NRT group had normal GMPI results. The mean left ventricular ejection fraction was 59.0% +/- 10.7% in the RT group and 59.3% +/- 9.8% in the NRT group (P = not significant). Good agreement was found between the GMPI results interpreted by multiple readers and those of the single expert reader (kappa = 0.84). In 7 of 10 patients (70%) who had abnormal GMPI results in the RT group, the myocardial perfusion defect was encompassed in RT isodose lines >/= 45 Gy, whereas in only 5 of 20 patients (25%) the normal left ventricle was included in the RT isodose line >/= 45 Gy.
RT is associated with a high prevalence of inferior left ventricular ischemia, as detected using GMPI in patients with distal esophageal cancer. Most perfusion defects are encompassed within an isodose line >/= 45 Gy in the RT plan.
先前已对淋巴瘤和乳腺癌患者放疗（RT）后心肌灌注异常的检测进行了研究。然而，食管癌患者中此类异常的发生率及其与放疗的相关性此前尚未得到研究。
将放疗后食管癌患者（放疗组）使用门控心肌灌注显像（GMPI）检测到的心肌灌注异常发生率与未接受放疗的食管癌患者（非放疗组）进行比较。患者数据来自前瞻性收集的数据库。由多名阅片者解读的GMPI结果由一名不了解患者临床信息的专家阅片者进一步检测。该阅片者的发现与放疗计划CT中所见的不同放疗等剂量线相关。记录GMPI中包含受累节段以及左心室其余部分的等剂量线。此外，收集每位患者心脏的平均辐射剂量信息。比较GMPI检查异常患者与GMPI检查正常患者心脏的总体平均辐射剂量。
共纳入51例患者，放疗组26例，非放疗组25例。放疗与GMPI之间的平均间隔和中位间隔分别为7.5个月和3.0个月。我们在放疗组14例患者（54%）中发现心肌灌注缺损，在非放疗组4例患者（16%）中发现心肌灌注缺损。放疗组11例患者（42%）有轻度下壁缺血，而非放疗组仅1例患者（4%）有轻度下壁缺血（P = 0.001）。所有下壁缺血患者均患有远端食管癌。放疗组其余12例患者和非放疗组21例患者GMPI结果正常。放疗组左心室平均射血分数为59.0%±10.7%，非放疗组为59.3%±9.8%（P = 无显著性差异）。多名阅片者解读的GMPI结果与单一专家阅片者的结果之间存在良好一致性（kappa = 0.84）。放疗组GMPI结果异常的10例患者中有7例（70%），其心肌灌注缺损包含在放疗等剂量线≥45 Gy内，而在20例正常左心室患者中只有5例（25%）其左心室包含在放疗等剂量线≥45 Gy内。
在远端食管癌患者中，放疗与使用GMPI检测到的左心室下壁缺血的高发生率相关。大多数灌注缺损包含在放疗计划中等剂量线≥45 Gy内。
