Fuentes R T, Holmes R A
Section of Nuclear Medicine, University of Missouri-Columbia Hospital and Clinics.
Clin Nucl Med. 1990 Apr;15(4):217-21. doi: 10.1097/00003072-199004000-00001.
A characteristic image pattern of diminished radioaerosol penetration and reduced radioparticle perfusion has been observed in endobronchial obstruction. This reverse mismatch has a variety of etiologies, with the most common being mucus plugging. The regional hypoxia created by the obstruction causes the blood to shunt from the affected lung. Eleven patients from a group of 178 patients referred with a working diagnosis of pulmonary embolism showed the reversed mismatch. All presented with sudden dyspenea, chest pain and hypoxia. Bronchoscopy was recommended from the image results and nine patients demonstrated mucus plugs that were subsequently aspirated, one patient had a partially obstructing endobronchial carcinoma and one patient had a traumatic fractured bronchus that became occluded with healing granulation tissue. All improved following bronchoscopy. The incompleteness of the airway obstruction accounted for the variations of the perfusion images. Because of the radioaerosol's ability to sharply image the pulmonary airway distribution in contrast to the poor resolution of the radiogases such as xenon-133, it is recommended that radioaerosol lung imaging be substituted for radiogas ventilation imaging since it can accurately detect endobronchial obstruction as well as pulmonary embolism.
在支气管内阻塞中观察到放射性气溶胶穿透减少和放射性颗粒灌注降低的特征性图像模式。这种反向不匹配有多种病因，最常见的是黏液堵塞。阻塞造成的局部缺氧导致血液从患侧肺分流。在一组178例初步诊断为肺栓塞的转诊患者中，有11例出现了反向不匹配。所有患者均表现为突发呼吸困难、胸痛和缺氧。根据影像结果建议进行支气管镜检查，9例患者发现黏液栓并随后吸出，1例患者有部分阻塞性支气管内癌，1例患者有创伤性支气管骨折，愈合的肉芽组织使其阻塞。所有患者在支气管镜检查后均有改善。气道阻塞的不完全性导致灌注图像的变化。由于放射性气溶胶与放射性气体（如氙-133）分辨率差相比，能够清晰地显示肺气道分布，因此建议用放射性气溶胶肺成像替代放射性气体通气成像，因为它可以准确检测支气管内阻塞以及肺栓塞。
