心肌灌注显像常见伪影的辨析

Discrimination of common myocardial tomography artifacts

为探讨心肌灌注显像常见伪影的特征、提高诊断的准确性 ,对 132例心肌断层影像进行了回顾分析 ,并以冠脉造影结果为标准判断伪影的有无。在充分识别各种伪影的情况下采用盲法重新诊断 ,并与既往诊断结果进行了比较。结果显示 :衰减伪影和位移伪影多见于2 0 1Tl显像者。其中胸壁衰减伪影女性多见 ,表现为位置固定的左室前壁或侧壁缺损 ;膈肌衰减伪影常见于男性 ,在垂直长轴上常表现为下壁由前向后逐渐变细。位移伪影常表现为室壁上的浓聚与稀疏的同时存在。非靶器官放射性摄取导致伪影 ,最多见于99mTc -MIBI显像的病人 ,此时常在三个断面上同时发现有肝或肠道影。重新读片后 ,误诊率由原来的 13.6 %下降到 6 .8%。此结果表明 ,各种伪影均有其影像特征和出现的特定前提 ;多数伪影在实践过程中能为人们所认识 ,但仍有部分伪影难于识别 ,认真分析其特征有助于进一步提高诊断的准确性。

To study the characteristics of common myocardial tomography artifacts so as to increase the diagnosis accuracy, 132 patients with myocardial perfusion were reviewed. With careful recognition of artifacts, the patients were re-diagnosed and compared with previous results. It was found that attenuation artifacts and motion artifacts were found frequently in thallium SPECT images. Artifacts caused by thoracic wall were frequent in female and showed a fixed defect in anterior or lateral wall; attenuation artifacts caused by left hemidiaphragm were always found in male and showed that the inferior wall became thinner gradually from apex to bottom in vertical long axis slices. The coexistence of defects and hot areas was the characteristics of motion artifacts. Artifacts caused by non-target organs, liver and/or gastrointestinal tracts, were frequently seen in 99mTc- sestamibi SPECT image. By recognizing the artifacts, misdiagnosis rate decreased significantly from 13.6% to 6.8%. Our studies show that all kinds of artifacts have their prevalence rate and imaging feature, the artifacts could be eliminated effectively by careful analysis and some correction measures.