Morrell N W, Nijran K S, Jones B E, Biggs T, Seed W A
Department of Medicine, Charing Cross and Westminster Medical School, London, UK.
Nucl Med Commun. 1993 Nov;14(11):983-8. doi: 10.1097/00006231-199311000-00008.
In the diagnosis of pulmonary embolism some centres using 133Xe for comparison with multiple view 99Tcm perfusion images perform only single-breath posterior view ventilation scans. The purpose of this study was to test the reliability of the posterior view ventilation scan in the detection of lobar and segmental defects in ventilation. Occluding balloon catheters were placed in lobar and segmental bronchi during fibreoptic bronchoscopy to produce defects of known anatomical location and size in normal volunteers. Subjects breathed 81Krm/air during the occlusions and images were acquired in the posterior, posterior/oblique and lateral projections. The posterior view images were classified by three experienced nuclear medicine physicians as normal or abnormal. If abnormal, the observers were asked to state which lobe or segment was involved. Segmental defects were missed in 28% of scan readings. Segmental defects were detected but incorrectly sited in 50% of readings and correctly sited in only 22% of readings. The posterior view scan with a defect involving the entire lingula was judged to be normal by all observers. Defects involving the right and left lower lobes were underestimated. We conclude that ventilation scanning techniques that assess the distribution of ventilation in the posterior view alone are unreliable in the detection of segmental and lobar defects, and are likely to increase the false positive rate in the diagnosis of pulmonary embolism.
在肺栓塞的诊断中，一些使用133Xe与多视角99Tcm灌注图像进行对比的中心仅进行单次呼吸后位通气扫描。本研究的目的是检验后位通气扫描在检测通气中肺叶和肺段缺损方面的可靠性。在纤维支气管镜检查期间，将阻塞性球囊导管放置在肺叶和肺段支气管中，以在正常志愿者中产生已知解剖位置和大小的缺损。在阻塞期间，受试者吸入81Krm/空气，并在后位、后斜位和侧位投影下采集图像。三位经验丰富的核医学医师将后位图像分类为正常或异常。如果图像异常，要求观察者指出受累的肺叶或肺段。在28%的扫描读数中遗漏了肺段缺损。检测到了肺段缺损，但在50%的读数中定位错误，仅在22%的读数中定位正确。所有观察者均将涉及整个舌叶的后位扫描判断为正常。涉及右肺下叶和左肺下叶的缺损被低估。我们得出结论，仅评估后位通气分布的通气扫描技术在检测肺段和肺叶缺损方面不可靠，并且可能会增加肺栓塞诊断中的假阳性率。
