The radiological changes in pulmonary venous hypertension, with special reference to the root shadows and lobular pattern

Comprehensive Cross-sectional Imaging of the Pulmonary Veins

The pulmonary veins carry oxygenated blood from the lungs to the heart, but their importance to the radiologist extends far beyond this seemingly straightforward function. The anatomy of the pulmonary veins is variable among patients, with several noteworthy variant and anomalous patterns, including supernumerary pulmonary veins, a common ostium, anomalous pulmonary venous return, and levoatriocardinal veins. Differences in pulmonary vein anatomy and the presence of variant or anomalous anatomy can be of critical importance, especially for preoperative planning of pulmonary and cardiac surgery. The enhancement or lack of enhancement of the pulmonary veins can be a clue to clinically important disease, and the relationship of masses to the pulmonary veins can herald cardiac invasion. The pulmonary veins are also an integral part of thoracic interventions, including lung transplantation, pneumonectomy, and radiofrequency ablation for atrial fibrillation. This fact creates a requirement for radiologists to have knowledge of the pre- and postoperative imaging appearances of the pulmonary veins. Many of these procedures are associated with important potential complications involving the pulmonary veins, for which diagnostic imaging plays a critical role. A thorough knowledge of the pulmonary veins and a proper radiologic approach to their evaluation is critical for the busy radiologist who must incorporate the pulmonary veins into a routine "search pattern" at computed tomography (CT) and magnetic resonance imaging. This article is a comprehensive CT-based imaging review of the pulmonary veins, including their embryology, anatomy (typical and anomalous), surgical implications, pulmonary vein thrombosis, pulmonary vein stenosis, pulmonary vein pseudostenosis, and the relationship of tumors to the pulmonary veins. Online supplemental material is available for this article. ^©RSNA, 2017.

Non-smokers are more prone to pulmonary oedema than smokers during acute coronary syndrome

OBJECTIVES

Acute coronary syndrome (ACS) patients are prone to develop pulmonary oedema with varied degree of hypoxaemia. The aim was to compare the risk for pulmonary oedema and related complications during ACS amongst non-smokers vs. smokers.

METHODS

Prospective, observational study was performed in consecutive 68 patients presenting with ACS. They were divided into two groups; group 1 (n = 33) non-smokers and group 2 (n = 35) chronic smokers. Standard conservative treatment was given to maintain mean arterial pressure >or= 60 mmHg, oxygen saturation > 95%. The bedside chest x-ray was graded for Battler grading (0-4) for pulmonary oedema. All patients were evaluated for troponin, serial creatinine kinase, echocardiography, arterial blood gas, renal function and correlated with inotropes requirement, active respiratory support, coronary care unit (CCU) stay and hospital outcome.

RESULTS

Patients in both the groups had similar cardiac involvement for cardiothoracic ratio, troponin, ejection fraction and creatinine kinase muscle and brain (CK-MB). The bedside chest x-ray revealed significant (p < 0.05) lung oedema grades (3 and 4) in 60% non-smokers (group 1) vs. smokers (11%). These patients (group 1) also presented with significant (p < 0.001) hypoxaemia (lower PaO(2)/FiO(2)-201 +/- 44), metabolic acidosis (higher lactate; 2.1 +/- 0.72 mmol/l, base deficit; -5.1 +/- 4.8) and hypocarbia (28 +/- 2.9 mmHg) than smokers (group 2). The risk estimates for active respiratory support (OR =1.716) and inotrope use (OR = 1.836) was three times higher in non-smokers than smokers.

CONCLUSIONS

The higher degree of pulmonary oedema and hypoxemia probably contributed to poor short-term outcome in non-smokers than smokers. It would be important to recognise and treat hypoxaemia in non-smokers during ACS.

Correlations between the chest film and hemodynamics in acute myocardial infarction

A series of 169 standardized chest films was analyzed relative to hemodynamic parameters obtained within 2 hr of the roentgenogram in 86 patients with acute myocardial infarction. The films were evaluated for cardiomegaly using the cardiothoracic ratio and the standardized, external left heart dimension. The radiographic appearance of the pulmonary vasculature was divided into levels of increasing severity: normal, pulmonary venous congestion, interstitial pulmonary edema, alveolar pulmonary edema. These were compared with wedge pressure levels of ⪕12, 13-18, 19-25, and >25 mm Hg, respectively. Correlations with the admission films of the 86 patients showed: 1) The appearance of the pulmonary vasculature accurately predicted the patient's wedge pressure on admission in 43% of the cases, overestimated it in 33% and underestimated it in 24%. 2) The presence of cardiomegaly and/or pleural effusion indicated an elevated wedge pressure with a high degree of certainty; however the absence of these signs did not exclude an elevated wedge pressure. 3) In only 62% of the studies was the chest film able to detect or exclude the presence of pulmonary venous hypertension. However, when wedge pressures were elevated to 19-25 mm Hg and over 25 mm Hg, 74% and 100%; respectively of roentgenograms had some evidence of pulmonary venous hypertension. 4) There was a high degree of correlation between the patient's admission physical findings, as evidenced by clinical classification, and the radiologic assessment of pulmonary venous hypertension.

There was no statistical variation in the accuracy of the estimate of wedge pressure in relation to the time elapsed from onset of symptoms of myocardial infarction. However, a therapeutic phase lag was encountered in 21 patients, the chest films remaining abnormal for a period of 1 to 4 days following return of the wedge pressure to normal. A diagnostic phase lag was encountered in 6 patients in whom the chest film did not correlate with elevation of wedge pressure for up to 12 hr. Furthermore, in 17 patients the films were normal in spite of a persistently elevated wedge pressure for 6 to 24 hr.

These studies document the limitations of the chest roentgenogram in predicting the hemodynamic status of patients with acute myocardial infarction.

Interstitial pulmonary edema

The diagnosis of interstitial pulmonary edema can be made only on the basis of the chest roentgenogram. This often is the first sign of left heart failure, which may be completely unsuspected clinically in the absence of alveolar edema. Kerley lines, or septal lines, are the most familiar roentgen sign of this condition. Other, more common findings include: perivascular and peribronchial cuffing, subpleural thickening, perihilar haze, and a generalized loss of translucency of the lung. Meticulous roentgen technic is essential for recognition of these subtle signs.