Wittram Conrad, Yoo Albert J
Division of Thoracic Radiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
J Thorac Imaging. 2007 May;22(2):125-9. doi: 10.1097/01.rti.0000213566.78785.26.
To test the hypothesis that a transient interruption of contrast is the result of an increase in flow of unopacified blood from the inferior vena cava (IVC) by comparing the relative IVC contribution to the right side of the heart in cases and age-matched and sex-matched controls.
This retrospective study was approved by our internal review board. Of 234 consecutive patients who had both CT pulmonary angiography and a close follow-up diagnostic pulmonary angiogram, or in one case CT pulmonary angiography, 7 cases were identified which contained a transient interruption of contrast. The study group included 2 men and 5 women. The age range was 37 to 77 years (mean 61.3 y +/-13.3). The artifact consists of a segment of the pulmonary arteries which demonstrates poor blood enhancement between areas of increased attenuation both proximally and distally. Hounsfield units (HU) measurements were made in the areas of decreased attenuation, the areas of higher attenuation both proximally and distally, the superior vena cava, IVC, right atrium (RA), and right ventricle (RV). The relative IVC contribution was calculated by equating density in the RA and RV to a weighted average of the densities of the superior vena cava and IVC. Age-matched and sex-matched controls and a 2-tailed paired t test were used.
In the patients with the artifact, the average relative IVC contributions to the RA and RV are 80.1% and 79.5%, respectively. In the control patients, the values for the RA and RV are 52.8% (P=0.02) and 55.5% (P=0.02), respectively.
Transient interruption of contrast of the pulmonary arteries represents a flow-related phenomenon associated with an increased IVC contribution to the right side of the heart.
通过比较病例组与年龄和性别匹配的对照组中下腔静脉（IVC）对右心的相对贡献，检验以下假设：对比剂的短暂中断是未显影的下腔静脉血流增加的结果。
本回顾性研究经我们的内部审查委员会批准。在连续234例接受CT肺动脉造影并进行密切随访诊断性肺动脉造影的患者中，或在1例仅接受CT肺动脉造影的患者中，发现7例存在对比剂短暂中断。研究组包括2名男性和5名女性。年龄范围为37至77岁（平均61.3岁±13.3岁）。伪影表现为肺动脉的一段，在近端和远端增强区域之间显示血液增强不佳。在衰减降低区域、近端和远端更高衰减区域、上腔静脉、下腔静脉、右心房（RA）和右心室（RV）进行Hounsfield单位（HU）测量。通过将RA和RV中的密度等同于上腔静脉和下腔静脉密度的加权平均值来计算下腔静脉的相对贡献。使用年龄和性别匹配的对照组以及双尾配对t检验。
在有伪影的患者中，下腔静脉对RA和RV的平均相对贡献分别为80.1%和79.5%。在对照患者中，RA和RV的值分别为52.8%（P = 0.02）和55.5%（P = 0.02）。
肺动脉对比剂的短暂中断代表一种与下腔静脉对右心贡献增加相关的血流相关现象。
