Oestmann J W, Greene R, Kushner D C, Bourgouin P M, Linetsky L, Llewellyn H J
Department of Radiology, Massachusetts General Hospital, Boston 02114.
Radiology. 1988 Feb;166(2):451-3. doi: 10.1148/radiology.166.2.3336720.
The influence of viewing time on the detectability of subtle and obvious lung cancers was studied. Frontal chest radiographs of 40 patients with subtle cancers, 40 patients with obvious cancers, and 40 healthy control subjects were shown to four observers for four different viewing times (0.25 second, 1 second, 4 seconds, and unlimited time). Receiver operating characteristic analysis was used to compare the detectability of lesions. Performance was degraded as viewing time decreased. The true-positive fractions for subtle and obvious cancers were 30% and 70% at 0.25 second and 74% and 98% at unlimited viewing time, respectively, for a given false-positive fraction of 20%. Thus, even with unlimited viewing time, the false-negative fraction for subtle cancers was 26%. The difference in detectability between subtle and obvious lung cancers was exaggerated at 1.0 second compared with 4 seconds and unlimited viewing time. The following conclusions were reached: (a) a substantial proportion of subtle lung lesions are missed, even with unlimited viewing time; (b) a large proportion of obvious lung cancers are detected with flash viewing; (c) the detectability of lesions decreases considerably as viewing time becomes less than 4 seconds; and (d) differences in detectability are exaggerated by short viewing times.
研究了观察时间对隐匿性和明显性肺癌可检测性的影响。向四名观察者展示了40例隐匿性癌症患者、40例明显性癌症患者和40名健康对照者的胸部正位X线片，观察时间分为四种（0.25秒、1秒、4秒和无限制时间）。采用受试者操作特征分析来比较病变的可检测性。随着观察时间减少，表现下降。对于给定的20%假阳性率，隐匿性和明显性癌症在0.25秒时的真阳性率分别为30%和70%，在无限制观察时间时分别为74%和98%。因此，即使无限制观察时间，隐匿性癌症的假阴性率仍为26%。与4秒和无限制观察时间相比，在1.0秒时隐匿性和明显性肺癌之间的可检测性差异被夸大。得出以下结论：(a)即使无限制观察时间，仍有相当比例的隐匿性肺部病变被漏诊；(b)大量明显性肺癌通过快速观察即可检测到；(c)当观察时间少于4秒时，病变的可检测性显著降低；(d)短观察时间会夸大可检测性差异。
