Chest XRay in Congestive Heart Failure

Sep 16, 2019 admin TIM MẠCH 0

Chest XRay in Congestive Heart Failure

Aka: Chest XRay in Congestive Heart Failure, CHF Chest XRay, Chest XRay in Left Ventricular Failure

II. Pathophysiology: Progression of chronic CHF

  1. Stage I: Pulmonary venous Hypertension with prominent upper lobe vessels (cephalization)
  2. Stage II: Interstitial Infiltrates (Kerley B Lines, peribronchial cuffing)
  3. Stage III: Alveolar Infiltrates (and Pleural Effusions)
    1. Interstitial fluid leak overwhelms lymphatic drainage capacity, overflowing into alveoli and pleural space
    2. Acute pulmonary edema typically presents with Stage III findings (without stage I or II)

III. Imaging: Stage I CHF XRay findings – Vascular phase – pulmonary venous Hypertension

  1. Cardiomegaly
  2. Pulmonary vasculature redistribution (Cephalization)
    1. Upper pulmonary vasculature becomes more prominent (upright Chest XRay)
    2. Normal, healthy patients have prominent lower lung field vasculature in contrast (upright Chest XRay)
    3. Redistribution will not be seen on supine xray
    4. Test Specificity: 80-90% for increased ventricular filling pressure
  3. Increased artery to Bronchus ratio
    1. Perihilar and upper lobe arteries (white round densities)
      1. Normally smaller in cross-section than Bronchi (dark round densities)
    2. Pulmonary vascular redistribution
      1. Results in an increased pulmonary artery diameter, larger than the bronch (ratio >1)
  4. Vascular pedicle broadens
    1. Mediastinal width increases at the level of the aortic arch or knob
  5. Pulmonary capillary wedge pressure (PCWP): 13-18 mmHg

IV. Imaging: Stage II CHF XRay findings – Interstitial phase

  1. Kerley B Lines (Interstitial Infiltrates)
    1. Short (1-2 cm) peripheral, lower lobe white lines, perpendicular and adjacent to pleura
  2. Peribronchial cuffing
    1. Bronchial wall thickening from interstitial edema (white rim around dark Bronchioles)
  3. Vessels become less distinct
    1. Hazy contours result from surrounding edema (perihilar haze)
  4. Interlobar fissure thickens (brighter white line between the lung lobes)
  5. Pulmonary capillary wedge pressure (PCWP): 18-25 mmHg

V. Imaging: Stage I CHF XRay findings – Alveolar phase

  1. Alveolar Infiltrates (Cottonwool appearance)
    1. Congestion is most dramatic centrally and in basal regions (bat-wing or butterfly appearance)
    2. Acute pulmonary edema (e.g. acute Left Ventricular Failure) may present with diffuse white-out appearance
  2. Air Bronchograms
    1. Dark Bronchioles become prominent in a background of white, fluid filled alveoli
  3. Pleural Effusion
  4. Pulmonary capillary wedge pressure (PCWP): >25 mmHg

VI. Imaging: Other findings

  1. Underlying lung disease
  2. Chamber enlargement
  3. Valve calcifications

VII. Differential Diagnosis

  1. Acute Respiratory Distress Syndrome (ARDS)
    1. History of major trigger (e.g. Trauma or surgery)
    2. No cardiomegaly
    3. No Pleural Effusions

VIII. Efficacy: CHF findings on Chest XRay

  1. Most useful initial test to assess for Congestive Heart Failure (as well as other causes of Dyspnea)
  2. Test Sensitivity: 71%
  3. Test Specificity: 92%

IX. Resources

  1. Congestive Heart Failure (Loyola Stritch School of Medicine)
    1. http://www.stritch.luc.edu/lumen/MedEd/Radio/curriculum/Medicine/chf1.htm
  2. Cremers, Bradshaw and Herfkens, Chest X-Ray – Heart Failure (Radiology Assistant)
    1. http://www.radiologyassistant.nl/en/p4c132f36513d4/chest-x-ray-heart-failure.html

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