Tips and Pearls for Chest X Ray part II

- Air fluid level

• Air fluid level in esophagus = esophageal stasis
• Intrapulmonary cavity with air fluid level - upper walls must be visible
• Hydropneumothorax = indistinct upper walls with different 'shape' of air fluid levels in PA and lateral view ( lower level can be outlined by the curved minor fissure )

- Thymoma can regularly metastasize to pleural layers

- Any opacity in diaphragm may arise below

- Lymph node with hypodense center - think about TB

- Ivory vertebrae ddx - adult - malignancy, lymphoma, Paget's disease of bone; kids - lymphoma, neuroblastoma, osteoblastoma, Ewing's sarcoma, osteosarcoma

- When the undersurface of the rib is eroded, the mass arises from the structure below the rib when it is found beneath the eroded rib

- There are 3 knobs on PA view in normal person - aortic knob, pulmonary arch and LV

• In MS, left auricle can be seen between pulmonary arch and LV
• A bulging pulmonary arch suggests PAH

- 3 ddx of bulging pulmonary arch

• Enlarged hilum + abrupt tapering of the vessels - PAH due to lung diseases or heart failure
• Enlarged hilum + increased vascularity seen in PA film - left to right shunt
• Normal or decreased vascularity without enlarged hilum - congenital pulmonic stenosis

- Kerley lines - A line, B line and C line

• Look for Kerley lines when u see reticular pattern 
• If CHF can be excluded, another ddx for Kerley line is lymphagitis carcinomatosis

- Aspiration due to achalasia normally goes to right apical lobe !!

- Upper lobe redistribution in hemithorax - CHF, MS or PE

- Hematoma can be suspected by seeing increased density of the mass in CT scan ( same as blood in LV )

- ABPA - tree in a bud pattern, can cause mucous impaction and lobar collapse

- PseudoPTX - the vessels will cross the pseudopleural line !!

- Oreo cookie sign - first layer - lung, second layer - fluid, third later - epicardial fat pad, diagnostic of effusion

- Lytic lesion in lung - MM, renal and thyroid cancer, blastic lesion ( Ivory rib ) - prostate cancer

- Air crescent sign - aspergilloma; water lily sign - hyatid cyst

- Know how to differentiate bullae vs pneumothorax

- Double density sign on aortic arch suggests a posterior mediastinal mass hiding behind the aorta

- Bronchiectasis can be cystic or cylindrical lesion

- Air below right diaphragm - pneumoperitoneum, pneumobilia ( Rigler's triad ), emphysematous cholecystitis and Chilaidit's syndrome

Tips and Pearls for Chest X Ray part I

- Humane approach to CXR interpretation : be curious, satisfy the need for search, KISS ( keep it simple, stupid !! )

- When assessing for airway position, do not forget to look at the esophagus !! Air fluid level + thickened retrotracheal line and displaced trachea to front is suspicious of esophageal stasis

- Rib notching w/o hypertension - do not diagnose coarctation of aorta

- If a mass overlies the ribs, assess whether there is any lytic lesion. You are done with your diagnosis if you could identify any bony involvements

- Pay attention to the spine and intervertebral disc when you are suspecting bone metastasis. Ivory vertebrae, collapsed disc are your clues that metastasis has happened

- Extrapulmonary mass must have distinct borders and forms obtuse angle with the lung. Another important sign is incomplete border sign.

- Pleural mass has in addition peripheral location and blunted costophrenic angle if located inferiorly

- A rounded atelectasis can be suggested if there is volume loss and the mass is located peripherally, pleural thickening and curvilinear vessels leading to it

- 3 complications of chronic pleural disease : malignancy, empyema necessitantis and bronchopleural fistula. 

• Malignancy can be distinguished by being a solid in CT scan. 
• Empyema necessitantis is a condition characterized by pus boring its way to the chest wall. 
• Bronchopleural fistula is characterized by an abnormal connection between the visceral pleura and the lung

- 3 subtle areas that can hide the mass - behind first rib, retrocardiac areas and subdiaphragmatic areas

- Always look in costophrenic angle and along the diaphragm for any nodular lesion ( in addition for effusion )

- A calcified nodule is likely to be benign

- A localized mass with air fluid level is highly suggestive of malignancy ( Squamous cell carcinoma )

- Always compare the position of left and right hilum. Left hilum usually is located between aortic knob and superior border of heart; right hilum just at the level of superior border of heart. A pulled up/down hilum suggests volume loss in that lung

- LLL collapse - sail sign, flat waist sign; LUL collapse - juxtaphrenic peak sign; Lufsichel sign

- Lufsichel sign is not only found around aortic knob, it can be a band of hyperlucency anywhere in the upper lobe of left lung

- If inspiratory and expiratory films are done, it is important to know before interpretation, which phase is pathological !!

- Congenital bronchial atresia is not uncommon. An area of hyperlucency with tubular density ( mucous impaction ) is suggestive

- Only 3 things cause tubular densities in lung - mucous, vascular lesions and herniated bowel loops

- The most common cause of lung collapse is cancer !!

- Fibrous dysplasia is not uncommon, seen as solitary lesion in a rib in a young patient

- Bulging of any of the mediastinal lines suggest mediastinal mass. Confirm with lateral X ray

- Always consider vascular pathology in ANY of the mediastinal mass ( mediastinum is made up of basically vessels )

- Look at the anterior clear space at lateral X ray for anterior mediastinal mass

- Superior mediastinal mass can be in anterior or posterior compartment. A superior mediastinal mass located posteriorly is likely a vascular lesion. It will show what is called cervicothoracic sign ( the mass will extend above clavicle )

- Always assess the centrality of the trachea. A displaced trachea in a S shaped manner suggests mass effect. Remember a trachea usually ends just at the beginning of the aortic arch. A displaced trachea at lateral film suggests mass effect

- Ddx of middle mediastinal mass depends on the location of the mass.

• A superiorly located - vascular mass; the most common is aortic aneurysm ; aortic aneurysm is also the most commonly mass that calcifies
• A middle-ly located - lymph nodes or duplication cyst ; look for bulging in azygoesophageal fissure
• An inferiorly located - esophageal pathology ( achalasia, stricture that leads to esophageal stasis )
• Always include esophageal pathology in ANY of the middle mediastinal lesions

- We only see the outer contour of aorta and  it's impossible to see the inner wall because it blends with mediastinal structures; a dilated aorta may not be dilated !!

- A dilated descending aorta + normal ascending aorta suggests type B aortic dissection

- Look in aortopulmonary window. A bulging window is suggestive of mass

- Unilateral lymph node and cavity - the top two ddx is TB and carcinoma

- Lymphoma causes anterior mediastinal lymphadenopathy as seen on CT