IN VIVO ASSESSMENT OF CANINE PROSTATE THERMAL ABLATIONS WITH MTI

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 前列腺癌是美国男性中最常见的恶性肿瘤，每年影响超过234，000名男性[1]。高强度超声是一种潜在的微创治疗方法。在MR引导下，这种治疗方法有可能局部消融前列腺组织，同时保留尿道或直肠壁等敏感组织。然而，虽然可以在MR引导下使用诸如PRF成像的技术来监测温度，并且可以使用对比增强成像来评估组织灌注，但是直接对由消融引起的前列腺组织变化进行成像的最佳方法不太清楚。先前已经注意到，还存在强磁化转移（MT）。 在前列腺组织中的作用[2]，这项工作的目的是研究MT成像是否可以提供有关体内高强度超声病变中前列腺组织变化的额外信息。 方法 在0.5 T Signa SP扫描仪（General Electric，密尔沃基，WI）上，用两个体内犬前列腺进行三次成像实验。从腹侧表面插入高强度间质超声施加器（10 mm x 180定向模式）[3]，在两只动物中创建两个损伤。给药后立即对前列腺进行成像，其中一只犬在4天后再次成像，然后处死。使用3D SPGR脉冲序列进行共振磁化传递成像，在扫描之间交替打开和关闭MT脉冲。共振脉冲为1-2-1二项式脉冲。使用MATLAB（The Mathworks，Natick，MA）使用等式1创建磁化率图像，并缩放到零和一之间。此外，通过创建的病变获取钆对比增强图像进行比较。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The most common malignancy in men in the United States, prostate cancer affects over 234,000 men each year [1]. High intensity ultrasound is a potential minimally invasive treatment capable of treating it. With MR guidance, this treatment option has the potential to locally ablate prostate tissue while preserving sensitive tissues like the urethra or rectal wall. However, while temperatures can be monitored under MR guidance, using such techniques as PRF imaging, and tissue perfusion can be assessed with contrast-enhanced imaging, the best methods of directly imaging the prostate tissue changes resulting from ablation are less clear. It has previously been noted that there is also a strong magnetization transfer (MT) effect in prostate tissue [2], and the purpose of this work was to investigate whether MT imaging could provide additional information concerning tissue changes in the prostate in high intensity ultrasound lesions in vivo. Methods Three imaging experiments were performed with two in vivo canine prostates on a 0.5T Signa SP scanner (General Electric, Milwaukee, WI). Two lesions were created in both animals with high intensity interstitial ultrasound applicators (10 mm x 180¿ directional pattern) [3] inserted from the ventral surface. The prostate glands were imaged immediately after treatment, and one of these dogs was imaged again four days later and then sacrificed. On-resonance magnetization transfer imaging was performed with a 3D SPGR pulse sequence, alternating the MT pulse on and off from scan to scan. The on resonance pulses were 1-2-1 binomial pulses. Magnetization ratio images were created using MATLAB (The Mathworks, Natick, MA) using equation 1 and scaled to between zero and one. Also, Gadolinium contrast enhanced images were acquired through the created lesions for comparison.