Denis Fabrice, Bougnoux Philippe, Paon Lénaïc, le Floch Olivier, Tranquart François
Institut National de la Santé et de la Recherche Médicale E 0211, CORAD, Centre Hospitalier Universitaire Bretonneau, 37044 Tours France.
J Ultrasound Med. 2003 Sep;22(9):921-9. doi: 10.7863/jum.2003.22.9.921.
To investigate the changes occurring in the vascularization of tumors during irradiation, we used a model of autochthonous mammary tumors in rats and assessed early vascular changes after irradiation by power Doppler sonography.
Mammary tumors were induced in 24 female Sprague Dawley rats by a single subcutaneous injection of N-nitroso N-methyl urea. After tumor areas reached 1 cm2, the animals received a single fraction of 18-Gy radiation or intraperitoneal saline injection. Power Doppler sonographic quantification of detected vessels was performed 1 day before irradiation and 7 days after the use of a power Doppler index of 5 different tumor imaging planes. Final tumor shrinkage was compared with early changes in the power Doppler index. Not all tumors regressed in a similar fashion. Radiosensitive tumors were defined as tumors with a greater than 50% decrease in baseline area 28 days after irradiation, whereas radioresistant tumors were tumors with a less than 50% decrease in baseline area. Statistical analysis was performed by the Mann-Whitney U test.
Tumor area changes were similar in radioresistant and radiosensitive tumors 7 days after irradiation (-41% and -35%, respectively; P > .05, not significant), whereas reduction in the power Doppler index was significantly greater in radiosensitive tumors (mean value, -63%) than in radioresistant tumors (mean value, -12%) (P = .001). Late tumor regrowth was correlated with day 7 power Doppler index changes (P = .009). A 40% reduction in the power Doppler index at day 7 distinguished 8 of 9 radiosensitive tumors and 8 of 9 radioresistant tumors (P = .003).
This study suggests that early changes in tumor perfusion as assessed by power Doppler sonography after tumor irradiation may precede the long-term tumor regression.
为了研究肿瘤在照射过程中血管生成的变化，我们使用了大鼠原位乳腺肿瘤模型，并通过功率多普勒超声评估照射后的早期血管变化。
通过单次皮下注射N-亚硝基-N-甲基脲在24只雌性Sprague Dawley大鼠中诱导乳腺肿瘤。当肿瘤面积达到1平方厘米后，动物接受单次18 Gy的辐射或腹腔注射生理盐水。在照射前1天和使用功率多普勒指数对5个不同肿瘤成像平面进行检测后7天，对检测到的血管进行功率多普勒超声定量分析。将最终肿瘤缩小情况与功率多普勒指数的早期变化进行比较。并非所有肿瘤都以相似的方式消退。放射敏感肿瘤定义为照射后28天基线面积减少超过50%的肿瘤，而放射抵抗肿瘤是指基线面积减少小于50%的肿瘤。采用Mann-Whitney U检验进行统计分析。
照射后7天，放射抵抗和放射敏感肿瘤的肿瘤面积变化相似（分别为-41%和-35%；P>.05，无显著性差异），而放射敏感肿瘤的功率多普勒指数降低（平均值为-63%）显著大于放射抵抗肿瘤（平均值为-12%）（P=.001）。晚期肿瘤再生长与第7天的功率多普勒指数变化相关（P=.009）。第7天功率多普勒指数降低40%可区分9个放射敏感肿瘤中的8个和9个放射抵抗肿瘤中的8个（P=.003）。
本研究表明，肿瘤照射后通过功率多普勒超声评估的肿瘤灌注早期变化可能先于长期肿瘤消退。
