Département de Radiologie, St Luc University Hospital - UCLouvain, Avenue Hippocrate 10, 1200 Bruxelles, Belgium.
Skeletal Radiol. 2011 Oct;40(10):1287-93. doi: 10.1007/s00256-011-1107-5. Epub 2011 Feb 25.
Hyperechoic microfoci are sometimes visualized in normal joints. We hypothesized that these microfoci may correspond to gas microbubbles produced by a vacuum phenomenon. The purpose of our study was to demonstrate the possibility of generating intraarticular hyperechoic microbubbles by creating a vacuum phenomenon through traction on a metacarpophalangeal joint.
We applied manual traction to the second metacarpophalangeal (MCP) joint of 22 volunteer subjects to separate articular surfaces with the aim of producing a vacuum. For one subject, the production of a vacuum was verified on a radiograph performed during the traction maneuver. For all subjects, ultrasonographic examination of the MCP joints was performed before, during, and after traction maneuvers. Two radiologists evaluated the presence of intraarticular hyperechoic microfoci and measured the widening of the joint space during traction.
In the first subject, the widening of the joint space and the production of an intraarticular gas-like cavity by traction was confirmed on the radiograph. In 10 out of the 22 volunteers, the widening of the joint space was immediately followed by the appearance of a large intraarticular hyperechoic band, which disappeared when the traction was stopped, followed by the appearance of hyperechoic microfoci that persisted several minutes. The widening of the joint during the traction maneuver was greater in the group where hyperechoic foci were produced than in the group with no hyperechoic foci (mean 2.5 vs. 1.2 mm and 2.2 vs. 0.8 mm, respectively, for observers 1 and 2; P < 0.05, Mann-Whitney U test).
Intraarticular hyperechoic microfoci may be produced and persist in normal joints after a traction maneuver. They are presumed to correspond to microbubbles created by a transient vacuum phenomenon.
正常关节有时可观察到高回声微焦点。我们假设这些微焦点可能对应于真空现象产生的气体微泡。本研究的目的是通过在手牚指关节上施加牵引来产生真空现象，从而证明在关节内产生高回声微泡的可能性。
我们对 22 名志愿者的第二掌指（MCP）关节施加手动牵引，以分离关节面，从而产生真空。对于一个受试者，在牵引操作过程中拍摄的 X 光片上验证了真空的产生。对于所有受试者，在牵引操作前后均对 MCP 关节进行超声检查。两位放射科医生评估了关节内高回声微焦点的存在，并测量了牵引时关节间隙的增宽。
在第一个受试者中，X 光片上确认了关节间隙的增宽和牵引时关节内气体样腔的形成。在 22 名志愿者中的 10 名中，关节间隙的增宽立即伴随着一个大的关节内高回声带的出现，当牵引停止时该带消失，随后出现高回声微焦点，该焦点持续数分钟。与没有高回声焦点的组相比，在产生高回声焦点的组中，关节在牵引操作过程中的增宽更大（观察者 1 和 2 分别为 2.5 毫米对 1.2 毫米和 2.2 毫米对 0.8 毫米；P<0.05，Mann-Whitney U 检验）。
在牵引操作后，正常关节内可能会产生并持续存在关节内高回声微焦点。它们可能对应于短暂真空现象产生的微泡。
