Mediastinum, diaphragm, and pleura imaging techniques and methods

Question 1

Contents of the mediastinum

Anterior
Middle
Posterior

Answer 1

Anterior: Thumus, Aortic arch branches and veins of the SVC

Middle: Heart, trachea, main bronchi, phrenic nerves,

Posterior: Esophagus, descending aorta, vagus nerve, sympathetic chain, thoracic duct, azygos and hemiazygos veins.

Lymph nodes are in all compartments
Paratracheal, 
Tracheobronchial
Crainal
Hilar,
Paraortic, etc

Question 2

Imaging for the mediastinum

Answer 2

All of them…
Ultrasound by TEE.
CXR, CT/MRI is prefered method

Question 3

Mediastinal disease

Answer 3

Pneumomediastinum - Esophageal rupture, bubbles air-shadows between mediastinal surfaces

Mediastinitis - T2 signal increase from inflammation and edema of mediastinal fat tissue, and mediastinal widening. Accompanied by pleural effusion.
Acute is life threatening, from esophageal perforation.
Chronic, is caused by radiation, with fibrosis.

Tumors- Thymoma, Lymphomas, Granulomas, Neurogenic tumors, Esophageal tumors, Hillar tumors of the lung.

Sarcoidosis, mediastinal and hilar node enlargement.

Question 4

Symmetrical mediastinal enlargment,

Answer 4

Malignant lymphomas or Leukemia, from hilar lymph node expansion.

Question 5

Hodgkin lymphoma

Answer 5

Unilateral mediastinal node enlargement.

Question 6

Diaphragm imaging

Answer 6

all of them……………………………… not US tho

Question 7

Reasons for bilateral diaphragm elevation

Answer 7

Obesity
Preggos

Ascites
Abdominal tumors
Hepatosplenomegaly

Question 8

Reasons for unilateral elevation

Answer 8

Phrenic nerve palsy/paralysis
Scoliosis and thoracic deformity

Ateletcasis of one lung

Subphrenic abscess or tumor

Question 9

Major diaphram alterations

Answer 9

Hiatal hernias - prolapse of stomach through hiatus

unilateral elevations
pleural effusions
gas under the diaphragm

Question 10

Pleura imaging

Answer 10

Normal pleural thickness is not seen on radiographs (Xrays)

Pleural lines are present on the horizontal and oblique fissures, visible faintly on X-ray and CT.
Pleural lines are only visible when they are in parallel orientation to the X-ray.
They are visible in the transverse plane on CT.

MR, and CT are the best methods for imaging pleural pathololies, although X ray also clearly shows pleural effusions or large pleural lesions.

Question 11

Pleural disease

Answer 11

Effusion -
Transudates: heart failure, renal failure, hypoproteinemia
Exudates: Lung or pleural cancer, TB infection, subphrenic abscesses, SLE and RA.
Hemothorax: trauma, hematological disease.
Chylothorax: thoracic duct injury
Empyema: ppneumonia, trauma, liver abscesses.

Pleural thickening:
infection,
encased effusions and pleural fibrosis
mesothelioma

Pneumothorax

pleural tumors:
cause effusion, should always be suspected in effusion of unknown origin.
CT can be used to differentiate the soft tissue of a potential tumor and the effusion fluid.

Benign: fibromas and lipomas, benign mesothelioma