MICRO-CT OF CARDIAC FUNCTION IN RAT WITH DOBUTAMINE CHALLENGE

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 研究设计 --动物：约。6周龄CD大鼠（250 gm）; n = 6 --供试品：多巴酚丁胺，30 ug/kg/min IV输注 定量终点-心脏总容量;左、右和间隔壁厚度; EDV、ESV、射血分数、每搏输出量、心输出量、短轴缩短分数 成像：所有成像将在杜克CIVM的第一代微型CT系统上进行。 我们将在相隔至少一周的两个不同时间采集6只动物心动周期中的12个点。每次治疗将包括一个基线，然后用多巴酚丁胺进行挑战。 时间顺序：2只动物成像/天X 3天。将动物放回笼中一周以恢复至基线生理状态，并重复研究。 体模校准：我们将使用具有准确已知体积的物体的体模来验证CT扫描协议和分析。将构建一个（静态）体模，其CT（Hounsfield）差异与动物（心肌/血池）的差异相当。将以至少1%的精度知道体模对象的体积。将使用产生对比噪声的技术扫描体模，对比噪声至少比临床（活体动物）环境中观察到的好2倍。我们将对图像集进行数字化修改，以生成与噪声对比度为0.5X、1.0 X和（原始）2.0 X CNR的图像。这将使我们能够将扫描和分割的任何错误来源与我们希望测量的生物变异性分开。 分析：将采用三种独立方法分析体模数据： - 使用Vitrea心脏功能分析进行自动分割 - 使用PSC浏览器自动分段 - 使用Image J进行半自动分割 在所有情况下，将报告相对于金标准（静态体模）的误差。此时，我们可以选择一种或两种方法应用于生物试验数据。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Study Design -- Animals: approx. 6 week old CD rats (250 gm); n = 6 -- Test article: Dobutamine, 30 ug/kg/min IV infusion Quantitative endpoints- total cardiac volume; left, right, and septal wall thickness; EDV, ESV, ejection fraction, stroke volume, cardiac output, fractional shortening Imaging: All imaging will be performed on the 1st-generation micro-CT system at the Duke CIVM. We will acquire 12 points in the cardiac cycle for 6 animals at two different times separated by at least one week. Each session will include a baseline followed by a challenge with dobutamine. Chronology: 2 animals imaged/day X 3 days. Animals will be returned to their cages for one week to recover to a baseline physiology and the study will be repeated. Phantom Calibrations: We will validate the CT scanning protocol and analysis using a phantom with objects of accurately known volumes. A (static) phantom will be constructed with CT (Hounsfield) differences comparable to those of the animal (myocardium/blood pool). The volumes of the phantom objects will be know with accuracy of at least 1%. The phantom will be scanned with techniques that produce contrast to noise at least 2X better than that seen in the clinical (live animal) setting. We will digitally alter the image sets to produce images with contrast to noise @ 0.5X, 1.0 X and (original) 2.0 X the CNR. This will allow us to separate any sources of errors from scanning and segmentation from the biological variability we wish to measure. Analysis: Phantom data will analyzed with three independent approaches : --- Autosegmentation using Vitrea cardiac functional analysis --- Autosegmentation using the PSC browser --- Semiautomated segmentation using Image J In all cases, the error will be reported relative to the gold standard (static phantom). At this point we may choose one or both methods to apply to the biological test data.