Morales Maria-Aurora, Prediletto Renato, Rossi Giuseppe, Catapano Giosuè, Lombardi Massimo, Rovai Daniele
CNR, Clinical Physiology Institute, Pisa, Italy.
J Clin Imaging Sci. 2012;2:25. doi: 10.4103/2156-7514.96540. Epub 2012 May 23.
The development of technologically advanced, expensive techniques has progressively reduced the value of chest X-ray in clinical practice for the assessment of left ventricular (LV) dilatation and dysfunction. Although controversial data are reported on the role of this widely available technique in cardiac assessment, it is known that the cardio-thoracic ratio is predictive of risk of progression in the NYHA Class, hospitalization, and outcome in patients with LV dysfunction. This study aimed to evaluate the reliability of the transverse diameter of heart shadow [TDH] by chest X-ray for detecting LV dilatation and dysfunction as compared to Magnetic Resonance Imaging (MRI) performed for different clinical reasons.
In 101 patients, TDH was measured in digital chest X-ray and LV volumes and ejection fraction (EF) by MRI, both exams performed within 2 days.
A direct correlation between TDH and end-diastolic volumes (r = .75, P<0.0001) was reported. TDH cut-off values of 14.5 mm in females identified LV end-diastolic volumes >150 mL (sensitivity: 82%, specificity: 69%); in males a cut-off value of 15.5 mm identified LV end-diastolic volumes >210 mL (sensitivity: 84%; specificity: 72%). A negative relation was found between TDH and LVEF (r = -.54, P<0.0001). The above cut-off values of TDH discriminated patients with LV systolic dysfunction - LVEF <35% (sensitivity and specificity: 67% and 57% in females; 76% and 59% in males, respectively).
Chest X-ray may still be considered a reliable technique in predicting LV dilatation by the accurate measurement of TDH as compared to cardiac MRI. Technologically advanced, expensive, and less available imaging techniques should be performed on the basis of sound clinical requests.
技术先进、价格昂贵的技术发展已逐渐降低了胸部X线在临床实践中评估左心室（LV）扩张和功能障碍的价值。尽管关于这一广泛应用的技术在心脏评估中的作用存在有争议的数据，但已知心胸比率可预测纽约心脏协会（NYHA）心功能分级进展、住院情况及LV功能障碍患者的预后。本研究旨在评估胸部X线测量心脏阴影横径（TDH）检测LV扩张和功能障碍的可靠性，并与因不同临床原因进行的磁共振成像（MRI）相比较。
对101例患者进行了数字胸部X线TDH测量及MRI测量LV容积和射血分数（EF），两项检查均在2天内完成。
报告TDH与舒张末期容积之间存在直接相关性（r = 0.75，P<0.0001）。女性TDH临界值为14.5 mm时，可识别舒张末期LV容积>150 mL（敏感性：82%，特异性：69%）；男性临界值为15.5 mm时，可识别舒张末期LV容积>210 mL（敏感性：84%；特异性：72%）。TDH与左室射血分数呈负相关（r = -0.54，P<0.0001）。上述TDH临界值可区分LV收缩功能障碍（左室射血分数<35%）患者——女性的敏感性和特异性分别为67%和57%；男性分别为76%和59%。
与心脏MRI相比，通过准确测量TDH，胸部X线在预测LV扩张方面仍可被视为一种可靠的技术。技术先进、价格昂贵且应用较少的成像技术应根据合理的临床需求进行。
