Huang Zheng, Haider Masoom A, Kraft Susan, Chen Qun, Blanc Dominique, Wilson Brian C, Hetzel Fred W
Radiation Oncology Department, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA.
Lasers Surg Med. 2006 Aug;38(7):672-81. doi: 10.1002/lsm.20375.
To determine the optimal magnetic resonance imaging (MRI) methodology to assess photodynamic therapy (PDT)-induced histopathological responses in the prostate.
STUDY DESIGN/MATERIALS AND METHODS: Laparotomy was performed in five healthy dogs. Cylindrical diffuser was placed in the prostates to deliver light of 50-300 J/cm at 150 mW/cm and 763 nm to activate IV-injected Tookad (1 mg/kg b.w.). Fast spin echo (FSE) T2-weighted, post-contrast-enhanced T1-(CE-T1) and diffusion weighted images (DWI) were obtained pre- and 2 days, 7 days, and 1 month post-PDT. Radiological-histopathological correlation was performed at 7 days (n = 4) and 1 month (n = 1) after PDT. A qualitative assessment of signal changes and apparent diffusion coefficient (ADC) mapping was performed.
At 2 or 7 days post-PDT, there was good spatial correlation between PDT-induced hemorrhagic necrosis and unenhanced regions on CE-T1 images. There was a rapidly and persistently enhancing rim corresponding to edema and inflammation. FSE T2 and DWI showed altered signal but did not clearly define necrosis in all cases. At 1 month, it was hard to correlate MR images to histopathologic changes as they represented a mixture of necrosis and developing fibrosis, which led to a mixed signal intensity and less demarcated contrast enhancement.
At 7 days after PDT, gadolinium DTPA contrast-enhanced MRI is superior to DWI and T2 imaging in assessing the boundary of Tookad PDT-induced tissue necrosis in the normal canine prostate.
确定评估光动力疗法（PDT）诱导的前列腺组织病理学反应的最佳磁共振成像（MRI）方法。
研究设计/材料与方法：对5只健康犬进行剖腹手术。将圆柱形扩散器置于前列腺内，以150 mW/cm的功率和763 nm的波长输送50 - 300 J/cm的光，以激活静脉注射的图卡德（1 mg/kg体重）。在PDT前、PDT后2天、7天和1个月获取快速自旋回波（FSE）T2加权、对比增强后T1（CE - T1）和扩散加权图像（DWI）。在PDT后7天（n = 4）和1个月（n = 1）进行放射学 - 组织病理学相关性分析。对信号变化和表观扩散系数（ADC）映射进行定性评估。
在PDT后2天或7天，PDT诱导的出血性坏死与CE - T1图像上的未强化区域之间存在良好的空间相关性。有一个对应于水肿和炎症的快速且持续强化的边缘。FSE T2和DWI显示信号改变，但并非在所有情况下都能清晰界定坏死区域。在1个月时，很难将MR图像与组织病理学变化相关联，因为此时图像表现为坏死和正在形成的纤维化的混合，导致信号强度混合且对比增强分界不清。
在PDT后7天，钆喷酸葡胺对比增强MRI在评估正常犬前列腺中图卡德PDT诱导的组织坏死边界方面优于DWI和T2成像。
