From the Guidelines
Kerley B lines are short, horizontal, parallel lines visible on chest X-rays that indicate thickening of the interlobular septa in the lungs, typically representing fluid accumulation due to increased pressure in the pulmonary veins 1. These lines are typically 1-2 cm in length and are most commonly seen at the lung periphery, especially at the costophrenic angles and lung bases. Their presence on a chest X-ray is an important diagnostic finding that helps clinicians identify increased interstitial fluid in the lungs. When a radiologist reports Kerley B lines, it should prompt investigation into potential cardiac dysfunction or other causes of interstitial lung disease, such as pulmonary edema caused by left heart failure, mitral stenosis, lymphangitic carcinomatosis, pulmonary fibrosis, and pulmonary lymphangiectasia 2, 3. The physiological basis for these lines is the accumulation of fluid or cellular infiltration in the normally thin interlobular septa, making them visible on radiographs when they would typically be too thin to be seen. In the context of pulmonary vascular occlusive disease (PVOD), the presence of Kerley B lines, along with other radiological findings such as subpleural thickened septal lines and centrilobular ground-glass opacities, can be suggestive of the diagnosis 3. It is essential to consider these findings in the context of clinical presentation and other diagnostic tests to guide further management and treatment. The use of point-of-care lung ultrasound can also aid in the evaluation of interstitial syndrome, with multiple B-lines being a sonographic sign of lung interstitial syndrome 1.
From the Research
Definition of Kerley B Lines
- Kerley B lines are a type of comet-tail artifact that indicates subpleural interstitial edema, as described in a study published in Chest in 2009 4.
- They are characterized as horizontal lines near the lung periphery, and their presence is associated with interstitial syndrome, which is usually related to interstitial edema.
Clinical Significance of Kerley B Lines
- Kerley B lines are a sign of pulmonary congestion and can be used to predict worsening heart failure in acute myocardial infarction during hospitalization and short-term follow-up, as shown in a study published in Frontiers in cardiovascular medicine in 2022 5.
- The presence of Kerley B lines can also be used to assess pulmonary hypertension in patients with interstitial lung diseases, with a correlation between the number of B-lines and the severity of pulmonary artery systolic pressure, as demonstrated in a study published in the Journal of ultrasound in medicine in 2015 6.
- Kerley B lines can be distinguished from other pulmonary signs, such as peribronchial cuffing and ground glass opacity, and can be used in combination with other signs to differentiate between cardiac/renal insufficiency and pulmonary interstitial lung disease, as described in a study published in Swiss medical weekly in 2019 7.
Radiographic Appearance of Kerley B Lines
- Kerley B lines can appear on chest X-rays, as described in a case report published in Nihon Kyobu Shikkan Gakkai zasshi in 1993 8.
- They can also be visualized using computed tomography (CT) scans, with a study published in Swiss medical weekly in 2019 showing that Kerley B lines in the lung apex are a distinct CT sign for pulmonary congestion 7.
- Lung ultrasound can also be used to detect Kerley B lines, with a study published in Chest in 2009 demonstrating the use of lung ultrasound to detect interstitial edema and predict pulmonary artery occlusion pressure 4.