Filho Guinel H, Du Jiang, Pak Byung C, Statum Sheronda, Znamorowski Richard, Haghighi Parviz, Bydder Graeme, Chung Christine B
Department of Radiology, University of California, 408 Dickinson St., San Diego, CA 92103-8226, USA.
AJR Am J Roentgenol. 2009 Mar;192(3):W117-24. doi: 10.2214/AJR.07.3990.
The objective of our study was to provide a quantitative means of evaluating the intrinsic T1 and T2() values of the Achilles tendon through the measurement of T1 recovery and T2() relaxation times, respectively, using ultrashort-TE (UTE) MRI at 3 T with histologic correlation.
Six cadaveric specimens underwent MRI at 3 T. The MRI protocol included standard MRI and UTE pulse sequences. For T1 measurement, a saturation recovery time method was applied (saturation recovery time range, 10-1,600 milliseconds), and for T2() measurements, a constant TR-varying TE method was used (TE, 100 microseconds-15 milliseconds). An analysis algorithm written in Matlab was executed offline on axial DICOM images for the T1 and T2() measurements in areas of normal tendon. The cadaveric specimens were subsequently frozen to -40 degrees C. They were sectioned with the slice thickness corresponding to the MR images. Anatomic sections were photographed and visually inspected. Specimens were then processed for histology. MR images, specimen photographs, and histology results were reviewed by two musculoskeletal radiologists and one pathologist.
Compared with histology results, the combination of UTE and standard MRI provided an accurate means of identifying normal tendon. The mean T1 measurement was 621 milliseconds and the mean T2(*) measurement was 2.18 milliseconds in histologically proven regions of normal tendon.
The UTE MR sequence offers structural information about and allows reproducible quantitative evaluation of tissues with short T2 components, such as tendons, that are inaccessible on conventional MRI. This technique showed T1 and T2(*) measurements in the normal Achilles tendon and allowed correlation with structural status by histology. Because of the small number of specimens, this is considered a feasibility study.
我们研究的目的是通过分别测量T1恢复时间和T2（）弛豫时间，利用3T场强下的超短回波时间（UTE）磁共振成像（MRI）并结合组织学相关性，提供一种定量评估跟腱固有T1和T2（）值的方法。
对6个尸体标本进行3T场强的MRI检查。MRI协议包括标准MRI和UTE脉冲序列。对于T1测量，应用饱和恢复时间法（饱和恢复时间范围为10 - 1600毫秒），对于T2（）测量，使用恒定TR - 可变TE法（TE为100微秒 - 15毫秒）。在Matlab中编写的分析算法在轴向DICOM图像上离线执行，以测量正常肌腱区域的T1和T2（）。随后将尸体标本冷冻至 - 40摄氏度。将其切成与MR图像对应的切片厚度。拍摄解剖切片并进行肉眼检查。然后对标本进行组织学处理。两名肌肉骨骼放射科医生和一名病理学家对MR图像、标本照片和组织学结果进行了评估。
与组织学结果相比，UTE和标准MRI的结合提供了一种识别正常肌腱的准确方法。在组织学证实的正常肌腱区域，平均T1测量值为621毫秒，平均T2（*）测量值为2.18毫秒。
UTE MR序列提供了有关具有短T2成分的组织（如肌腱）的结构信息，并允许对其进行可重复的定量评估，而这些组织在传统MRI上无法显示。该技术显示了正常跟腱的T1和T2（*）测量值，并通过组织学与结构状态相关联。由于标本数量较少，本研究被视为一项可行性研究。
