تعيين حساسيت و ويژگي روشهاي تخمين اندازه قلب در گرافي ساده قفسه صدري يا اكوكارديوگرافي

Comparison of sensitivity and specificity of cardiac size in chest radiography with 2D echocardiography

Despite the more accurate and advanced cardiac, imaging techniques. simple chest X-ray (CXR) is the first technique for evaluation of heart size. There are tow main methods for this evaluation on CXR: measurement of transverse diameter of the heart (TD) and cardiothoracic ratio (CTR). The normal range of TD is 11.5 to 15.5 and its upper normal limit for men and women is 16 and 15 centimeters (cm). The mean value of CTR is 44% and its upper normal limit is 50%. These upper limits which are used widely, lead to some difficulties in practice: some patients with normal heart size on CXR, have enlargement of heart in more accurate techniques and conversely some individuals with cardiomegaly on CXR do not have enlargement. These discrepancies may lead to some mistakes in management of patients. So we decided to perform this study for assessment of these measurement methods of cardiac size in CXR by more accurate technique of echocardiography. This analytical study was performed on 327 cases referred to echocardiography center of Hajar Hospital in Shahrekord for standard CXR during summer, 2001. Considering 50% and 16cm as the upper normal limits of CTR and TD, we had 28.2% and 8.8% false positive and 9.2% and 58.5% false negative results respectively. It can be concluded that CTR is more sensitive than TD but TD is more specific than CXR for estimating of cardiomegaly.