Department of Radiology Cell Isolation and Transplant Center, Department of Surgery, University of Geneva School of Medicine and Geneva University Hospitals, Geneva, Switzerland.
Am J Transplant. 2011 Jun;11(6):1158-68. doi: 10.1111/j.1600-6143.2011.03559.x. Epub 2011 May 12.
The Automatic Quantitative Ultrashort Echo Time imaging (AQUTE) protocol for serial MRI allows quantitative in vivo monitoring of iron labeled pancreatic islets of Langerhans transplanted into the liver, quantifying graft implantation and persistence in a rodent model. Rats (n = 14), transplanted with iron oxide loaded cells (0-4000 islet equivalents, IEQ), were imaged using a 3D radial ultrashort echo time difference technique (dUTE) on a Siemens MAGNETOM 3T clinical scanner up to 5 months postsurgery. In vivo 3D dUTE images gave positive contrast from labeled cells, suppressing liver signal and small vessels, allowing automatic quantification. Position of labeled islet clusters was consistent over time and quantification of hyperintense pixels correlated with the number of injected IEQs (R² = 0.898, p < 0.0001), and showed persistence over time (5 months posttransplantation). Automatic quantification was superior to standard imaging and manual counting methods, due to the uniform suppressed background and high contrast, resulting in significant timesavings, reproducibility and ease of quantification. Three-dimensional coverage of the whole liver in the absence of cardiac/respiratory artifact provided further improvement over conventional imaging. This imaging protocol reliably quantifies transplanted islet mass and has high translational potential to clinical studies of transplanted pancreatic islets.
用于连续 MRI 的自动定量超短回波时间成像 (AQUTE) 方案允许对移植到肝脏中的铁标记胰岛进行活体定量监测，从而在啮齿动物模型中定量评估移植物的植入和持续存在情况。用载氧化铁细胞（0-4000 胰岛当量，IEQ）移植的大鼠（n = 14），在 Siemens MAGNETOM 3T 临床扫描仪上使用 3D 径向超短回波时间差技术（dUTE）进行成像，直至手术后 5 个月。体内 3D dUTE 图像对标记细胞产生正对比，抑制肝脏信号和小血管，从而可以自动定量。标记胰岛簇的位置随时间保持一致，并且超亮像素的定量与注射的 IEQ 数量相关（R² = 0.898，p < 0.0001），并且随时间推移具有持续存在性（移植后 5 个月）。自动定量比标准成像和手动计数方法优越，因为背景均匀抑制且对比度高，从而显著节省时间、提高重现性和便于定量。在不存在心脏/呼吸伪影的情况下，对整个肝脏进行 3D 覆盖，进一步优于传统成像。这种成像方案可靠地定量了移植的胰岛质量，并且具有很高的转化潜力，可以用于移植的胰腺胰岛的临床研究。
