ACUTE AND CRHRONIC MT RATIO OBSERVATIONS IN CANINE CRYOABLATION

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。子项目及 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。 介绍 前列腺癌是美国男性中最常见的侵袭性肿瘤，每年有超过234，000人被诊断患有前列腺癌，冷冻消融术是一种潜在的微创治疗方法。 在磁共振引导下，这种治疗方法可以有效地局部消融前列腺组织，同时保留尿道或直肠壁等敏感结构。虽然冰球的形成可以用MR监测，但随后对组织损伤的评估不太清楚。灌注可以通过对比增强（CE）成像进行评估，但需要进一步的愈合组织表征。 在先前的研究中，我们注意到治疗后14天和53天冷冻损伤中的低磁化传递（MT）对比区域。 本研究跟踪了从治疗后即刻至数周后处死犬时，在三只犬中产生的冷冻损伤中的MT效应。 这项工作的目的是研究MT效应的缺乏是否在治疗后立即明显，并监测其如何随时间推移而进展，将MT效应与CE和组织学进行比较。 方法 在0.5 T Signa SP扫描仪（GE Healthcare，沃基沙，WI）上进行了三次MRI引导的犬前列腺冷冻消融术。 每次冷冻消融术都会在前列腺内造成多处损伤。 消融后，所有犬均采用MT脉冲序列成像，然后进行钆CE成像。 MT脉冲序列在多层2D和3D SPGR序列中实现每次扫描交替打开和关闭的共振1-2-1二项式脉冲。在给药后第7天和第21天研究终止时，采用相同的随访成像方案对两只犬（犬1和2）进行成像，而第三只犬（犬3）在第7天和第14天（研究终止）进行成像。 最终成像后，对每只犬实施安乐死，并采集前列腺进行组织学分析。

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. Introduction Prostate cancer is the most common invasive neoplasm in men in the United States; each year over 234,000 men are diagnosed with it. A potential minimally invasive treatment is cryoablation. With MR guidance, this treatment option could prove effective in locally ablating prostate tissue while preserving sensitive structures like the urethra or rectal wall. While iceball formation can be monitored with MR, assessment of tissue damage afterwards is less clear. Perfusion can be assessed with contrast enhanced (CE) imaging, but further tissue characterization of healing is desired. In previous studies, we noticed regions of low magnetization transfer (MT) contrast in cryolesions fourteen and fifty-three days after treatment. This current study follows the MT effect in cryolesions created in three canines, from immediately after treatment to weeks later when the dogs were sacrificed. The purpose of this work was to investigate if the lack of MT effect was evident immediately following treatment and to monitor how it progressed over time, comparing MT effect to CE and histology. Methods Three MRI-guided canine prostate cryoablations were performed in vivo on a 0.5T Signa SP scanner (GE Healthcare, Waukesha, WI). Each cryoablation procedure created multiple lesions within the prostate. After ablation, all dogs were imaged with MT pulse sequences, followed by Gadolinium CE imaging. The MT pulse sequences implemented on-resonance 1-2-1 binomial pulses alternating on and off per scan in both multislice 2D and 3D SPGR sequences. Two dogs (Dogs 1 and 2) were imaged with the same follow-up imaging protocol at seven days and at study termination - twenty-one days after treatment, while the third dog (Dog 3) was imaged at seven days and fourteen days (study termination). After the final imaging session, each dog was euthanized and the prostate harvested for histological analysis.