Ng W H, Chan Y L, Sung J Y, Lee Y T, Lee S F, Chung S S C
Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
MAGMA. 2004 Apr;16(5):211-7. doi: 10.1007/s10334-003-0026-4. Epub 2004 Mar 12.
Azygos venous blood flow as an index of blood flow through the gastroesophageal collaterals and varices is of value in the prediction of gastrointestinal bleeding. Measurement of azygos venous blood flow has been achieved by non breath-hold (NBH) cine phase-contrast magnetic resonance imaging. The objective of this study was to compare the faster breath-hold (BH) phase-contrast technique with the standard (NBH) cine phase-contrast technique in the measurement of azygos blood flow. Thirty-two cirrhotic patients with esophageal varices were examined by magnetic resonance imaging using a BH technique and a NBH cine phase-contrast technique to measure the flow velocity, flow volume and calibre of the azygos vein at the mid-right atrial level. The flow values were obtained on the velocity image of the phase-contrast study. Values obtained from the two methods were evaluated statistically for the strength and significance of correlation by the Pearson test. Measurement by the BH method performed at full-inspiration as well as end-expiration was also obtained in 15 healthy volunteers. The breath-hold phase-contrast method has significant but weak correlation with non BH cine phase-contrast method in the measurement of azygos venous blood flow volume (r = 0.55, p < 0.01) and flow velocity (r = 0.43, p = 0.01). However, the calibre of the azygos vein gave a strong correlation in these two methods (0.82). In the subgroup of patients whose azygos blood flow velocity was greater than 7.4 cm/s, the correlation of azygos blood flow volume is strong (r = 0.80, p < 0.01). The azygos vein calibre remains highly correlated between the BH and NBH method, in both high flow velocity (r = 0.73) and low flow velocity (r = 0.83) groups. Breath-hold sequence leads to higher values for flow velocity and flow volume in the cirrhotic patients and also the control group. In patients with portal hypertension, BH 2D phase-contrast (PC) magnetic resonance angiography (MRA) could give a comparable estimation of the calibre of the azygos vein as the NBH 2D cine PC MRA but not for azygos flow volume. In patients with high azygos flow velocity, the strong correlation in flow volume between the BH and NBH method suggests that the BH method may be a time-saving alternative to the NBH method.
奇静脉血流作为流经胃食管侧支循环和静脉曲张的血流指标，在预测胃肠道出血方面具有重要价值。奇静脉血流的测量已通过非屏气（NBH）电影相位对比磁共振成像实现。本研究的目的是比较快速屏气（BH）相位对比技术与标准（NBH）电影相位对比技术在测量奇静脉血流方面的差异。对32例患有食管静脉曲张的肝硬化患者进行磁共振成像检查，采用BH技术和NBH电影相位对比技术测量右心房中部水平奇静脉的流速、流量和管径。血流值从相位对比研究的速度图像中获取。通过Pearson检验对两种方法获得的值进行统计学评估，以确定相关性的强度和显著性。还对15名健康志愿者在深吸气和呼气末进行了BH方法测量。屏气相位对比法与非屏气电影相位对比法在测量奇静脉血流量（r = 0.55，p < 0.01）和流速（r = 0.43，p = 0.01）方面具有显著但较弱的相关性。然而，奇静脉管径在这两种方法中具有很强的相关性（0.82）。在奇静脉血流速度大于7.4 cm/s的患者亚组中，奇静脉血流量的相关性很强（r = 0.80，p < 0.01）。在高流速（r = 0.73）和低流速（r = 0.83）组中，BH和NBH方法之间的奇静脉管径仍高度相关。屏气序列导致肝硬化患者和对照组的流速和流量值更高。在门静脉高压患者中，BH二维相位对比（PC）磁共振血管造影（MRA）对奇静脉管径的估计与NBH二维电影PC MRA相当，但对奇静脉流量的估计则不然。在奇静脉流速较高的患者中，BH和NBH方法在流量方面的强相关性表明，BH方法可能是一种比NBH方法更节省时间的替代方法。
