O'Shaughnessy A M, Fitzgerald D E
Vascular Medicine Unit, James Connolly Memorial Hospital, Blanchardstown, Dublin, Ireland.
Int Angiol. 2000 Sep;19(3):220-7.
In vitro studies have shown that as the organisation of a thrombus progresses its ultrasound appearance becomes more echogenic. When diagnosing a deep vein thrombosis (DVT) using duplex ultrasound, an estimation of the degree of organisation of the thrombus is made by assessing its echogenicity. This method is purely subjective and has many pitfalls.
A study was performed on 100 proximal DVTs from 89 patients diagnosed by duplex ultrasound. These images were transferred to a computer and standardised using, the adobe Photoshop. The thrombus in the image frame was outlined and the grey scale median (GSM) calculated. The grey scale median which is a measure of the echogenicity of the thrombus (indicating the degree of organisation), varied considerably from patient to patient.
The results show that the level of organisation of a thrombus on initial diagnosis is unrelated to the clinical signs or duration of symptoms of the patient. This has further implications when considering a therapy regimen based on the duration of symptoms (e.g. thrombolysis). Additionally, the age of the patient, predisposing factors and bulk of the thrombus appear to be unrelated to the value of the grey scale median at the initial visit. The initial grey scale median values were then compared to those at a one week's follow-up examination. Those with a low initial value of the grey scale median were found to increase, indicating further organisation, as expected. However, patients with higher initial grey scale median values were found to fluctuate, some increasing and some decreasing. The increase the grey scale median was due to a more homogenous appearance across the thrombus as the organisation process became more established. A decrease in grey scale median indicated areas of lysis occurring within the thrombus.
Measuring the value of the grey scale median is a quantitative way of assessing the degree of organisation of a deep vein thrombosis. This can be used to asses the suitability of patients for various treatment regimen. It is also a useful means of assessing the long-term implications of different therapies and could aid in determining the long-term outcome for the patient.
体外研究表明，随着血栓结构的进展，其超声表现变得更加回声增强。使用双功超声诊断深静脉血栓形成（DVT）时，通过评估血栓的回声性来估计血栓的结构程度。这种方法完全是主观的，存在许多缺陷。
对89例经双功超声诊断的患者的100个近端DVT进行了研究。这些图像被传输到计算机上，并使用Adobe Photoshop进行标准化处理。勾勒出图像帧中的血栓，并计算灰度中位数（GSM）。灰度中位数是血栓回声性的一种度量（指示结构程度），患者之间差异很大。
结果表明，初次诊断时血栓的结构水平与患者的临床体征或症状持续时间无关。在考虑基于症状持续时间的治疗方案（例如溶栓）时，这具有进一步的意义。此外，患者的年龄、诱发因素和血栓大小似乎与初次就诊时的灰度中位数无关。然后将初始灰度中位数与一周后的随访检查结果进行比较。发现初始灰度中位数较低的患者有所增加，表明如预期的那样有进一步的结构形成。然而，发现初始灰度中位数较高的患者会出现波动，有些增加，有些减少。灰度中位数的增加是由于随着结构形成过程更加稳定，血栓整体外观更加均匀。灰度中位数的降低表明血栓内发生了溶解区域。
测量灰度中位数是评估深静脉血栓形成结构程度的一种定量方法。这可用于评估患者对各种治疗方案的适用性。它也是评估不同疗法长期影响的有用手段，有助于确定患者的长期预后。
