定量磁化率映射检测 legg-calvé-perthes 病猪模型缺血性损伤后骺软骨新生血管形成。
Quantitative susceptibility mapping detects neovascularization of the epiphyseal cartilage after ischemic injury in a piglet model of legg-calvé-perthes disease.
机构信息
Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA.
Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.
出版信息
J Magn Reson Imaging. 2019 Jul;50(1):106-113. doi: 10.1002/jmri.26552. Epub 2018 Dec 17.
BACKGROUND
Legg-Calvé-Perthes disease (LCPD) is a childhood hip disorder thought to be caused by disruption of blood supply to the developing femoral head. There is potential for imaging to help assess revascularization of the femoral head.
PURPOSE
To investigate whether quantitative susceptibility mapping (QSM) can detect neovascularization in the epiphyseal cartilage following ischemic injury to the developing femoral head.
STUDY TYPE
Prospective.
ANIMAL MODEL
Right femoral head ischemia was surgically induced in 6-week-old male piglets. The animals were sacrificed 48 hours (n = 3) or 4 weeks (n = 7) following surgery, and the operated and contralateral control femoral heads were harvested for ex vivo MRI.
FIELD STRENGTH/SEQUENCE: Preclinical 9.4T MRI to acquire susceptibility-weighted 3D gradient echo (GRE) images with 0.1 mm isotropic spatial resolution.
ASSESSMENT
The 3D GRE images were used to manually segment the cartilage overlying the femoral head and were subsequently postprocessed using QSM. Vessel volume, cartilage volume, and vessel density were measured and compared between operated and control femoral heads at each timepoint. Maximum intensity projections of the QSM images were subjectively assessed to identity differences in cartilage canal appearance, location, and density.
STATISTICAL TESTS
Paired t-tests with Bonferroni correction were used (P < 0.008 considered significant).
RESULTS
Increased vascularity of the epiphyseal cartilage following ischemic injury was clearly identified using QSM. No changes were detected 48 hours after surgery. Vessel volume, cartilage volume, and vessel density were all increased in the operated vs. control femoral heads 4 weeks after surgery (P = 0.001, 0.002, and 0.001, respectively). Qualitatively, the increase in vessel density at 4 weeks was due to the formation of new vessels that were organized in a brush-like orientation in the epiphyseal cartilage, consistent with the histological appearance of neovascularization.
DATA CONCLUSION
QSM can detect neovascularization in the epiphyseal cartilage following ischemic injury to the femoral head.
LEVEL OF EVIDENCE
1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:106-113.
背景
Legg-Calvé-Perthes 病（LCPD）是一种儿童髋关节疾病，被认为是由于发育中的股骨头血液供应中断引起的。影像学检查有可能帮助评估股骨头的再血管化。
目的
研究定量磁化率映射（QSM）是否可以检测到发育性股骨头缺血后骺软骨中的新生血管形成。
研究类型
前瞻性。
动物模型
6 周龄雄性小猪行右侧股骨头缺血手术。术后 48 小时（n=3）或 4 周（n=7）处死动物，采集手术侧和对侧正常股骨头进行离体 MRI。
磁场强度/序列：在临床前 9.4T MRI 上采集具有 0.1mm 各向同性空间分辨率的磁化率加权 3D 梯度回波（GRE）图像。
评估
使用 3D GRE 图像手动分割覆盖股骨头的软骨，并使用 QSM 对其进行后处理。在每个时间点测量并比较手术侧和正常侧股骨头的血管容积、软骨容积和血管密度。对 QSM 图像的最大强度投影进行主观评估，以确定软骨管外观、位置和密度的差异。
统计学检验
使用配对 t 检验（Bonferroni 校正后，P<0.008 认为有统计学意义）。
结果
缺血性股骨头损伤后骺软骨的血管生成明显可通过 QSM 识别。术后 48 小时未发现变化。术后 4 周，手术侧与正常侧股骨头的血管容积、软骨容积和血管密度均增加（P=0.001、0.002 和 0.001）。定性分析，4 周时血管密度的增加是由于新血管的形成，这些新血管在骺软骨中呈毛刷状排列，与新生血管的组织学表现一致。
数据结论
QSM 可以检测到头状骨缺血后骺软骨中的新生血管形成。
证据水平
1 技术功效：阶段 1 J. Magn. Reson. Imaging 2019;50:106-113.
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