Diagnostics Pulm Radiology

The average accumulated background of radiation dose to an individual for one year, exclusive of radon in US

1 mSv, by exposure to 1 mG of radiation

What is the mean radiation doe to adult from a chest radiograph (front vs side)

0.02 for PA and 0.08 for LL

Indications of a CXR

Diagnose conditions involving the chest wall- can include bony structures, lungs, heart, great vessels

screen for job related lung diseases

check position of medical equipment

initial screening tool for cancer or TB

When is a CXR emergent

chest pain, SOB, chest injury, hemoptysis, decreased breath sounds, determination for pneumothorax, pneumonia, rib fracture, cardiomegaly, effusion

When is a CXR urgent

symptoms lasting more than 3 weeks without obvious diagnostic cause; changes in cough or new cough, dyspnea, chest or shoulder pain

When is a CXR chronic

follow up, surveillance for COPD and lung cancer

Using a CXR for preventative screening

not generally recommended due to limited effectiveness for early lung cancer (low sensitivity) and false positives. It should be used for screening in specific situations like when individuals are exposed to occupational lung diseases or high risk populations where access to LDCT is limited

CXR CI

No absolute CI

consider in pregnancy, children, metal implants (more for MRI), immobility, medical necessity

What do you need to do before interpreting any CXR

verify name, MRN, correct date, correct study

What are CXR markers used for

put on images to determine side of body or landmark by writing date of procedure or name, or R and L

CXR during expiration

this increases the attenuation of the normal lung, increases the contrast between lung and pneumothorax or the demonstration of unilateral air trapping as lungs appear denser, widening of cardiac silhouette due to more horizontal position and increased basal opacity with obscures the pulmonary blood vessels, mimicking lung disease

heart appear larger, mediastinum shifts to normal side, scapulas tucked, sensitivity not increased over inspiratory CSR in detecting pneumothoraxes

CXR during inspiration

generally better quality, lungs more expanded, diaphragm below 9th rib, heart and mediastinum less enlarged, lung bases less hazy, scapulas winged

What is considered a well penetrated CXR

Penetration is the degree to which Xray's have passed through the body. A well penetrated is one where the vertebrae are just visible behind the heart, and the left hemidiaphragm should be visible to the edge of the spine

In what cases would there be a loss of hemidiaphragm contour or of the paravertebral tissue lines in CXR?

lung or mediastinal pathology

What does overpenetration look like on a CXR?

overexposed, too dark, lungs look black, too many x rays reaching x ray plate

What does under penetration look like on CXR?

underexposed, lung and heart too white, cannot see spine behind heart, too few x rays reaching Xray plate

Problems with rotating CXR

interpretation is difficult: difficult to know if trachea is deviated, lung density changes due to asymmetry of overlying soft tissue, difficult to comment accurately on heart size, thickness of soft tissue in chest is altered, spinous processes lie nearer one clavicle than the other

What to give attention to with describing abnormalities in CXR

location, size, shape, density of abnormality

Density on CXR

an area on the x ray that is brighter than expected

Opacity on CXR

an area of increased density on the xray

Lucency on CXR

the opposite of density, where more x-rays pass through less dense regions; abnormal lucency can occur when there is too much of it or when it's an atypical location

Consolidation of CXR

a pattern of abnormal pulmonary opacification

Atelectasis on CXR

a pattern of abnormal pulmonary opacification that indicates collapse

Interstitial opacification on CXR

a pattern of abnormal pulmonary opacification that appears as lines

Nodular opacification on CXR

a pattern of abnormal pulm opacification that appears at dots

Pleural thickening on CXR

may be a sign of lung cancer, idiopathic interstitial pneumonia, or mycobacterial infection

Air trapping on CXR

the retention of air in lung parenchyma distal to an obstruction of one or more airways

What are alveolar infiltrates on the chest X ray?

these are areas of increased density or opacity on a chest xray or CT scan that indicate fluid, inflammation, or other abnormalities in the alveoli

Appearance of alveolar infiltrates on the CXR

patchy or diffuse areas of increased density; air bronchograms (black lines representing airways surrounded by infiltrates); may have puffy of ground glass appearance

Causes of alveolar infiltrates

pneumonia, pulmonary edema, ARDS, diffuse alveolar hemorrhage, lung cancer, pulmonary embolism

What are interstitial infiltrates on CXR

buildup of cells or noncellular material in the tissue surrounding the air sacs in the lungs- they are abnormalities seen on imaging tests such as CXR or CT that indicate inflammation or fluid accumulation in the interstitial space of the lungs

What are the causes of interstitial infiltrates

infection such as pneumonia, TB, sarcoidosis, AI such as RA, lupus, scleroderma, environmental exposure like asbestos, silica, coal dust, medications like chemo or ABX, and idiopathic

Alveolar vs Interstitial Opacities

alveolar = air sacs

They are radiolucent and can contain blood, mucous, tumor, or edema

Interstitial = vessels, lymphatics, bronchi, and CT

Radio dense, interstitial disease with prominent lung markings with aerated lungs

ABCDE of CXR interpretation

airway, bones, cardiac, diaphragm, everything else

Airway of CXR

trachea, mediastinal width, aortic knob

DO NOT MISS deviate trachea

B of CXR

lung field outlines, symmetry, pleural

DO NOT MISS pneumothrorax

C of CXR

heart size on PA film, heart borers, heart shape

D of CXR

hemidiaphragm levels, diaphragm shape or contour, costophrenic angles

DO NOT MISS subdiaphragmatic free air (pneumo-peritoneum)

E of CXR

NG tube, pacemaker, ECG electrodes, PICC line, foreign body, ET tube

RIPE pneumonic for CXR image quality

Rotation: medial aspect of each clavicle should be equidistant from the spinous processes

Inspiration: the 5-6 anterior ribs, lung apices, both costophrenic angles and the lateral rib edges should be visible

Projection: not if AP or PA view

Exposure: the left hemidiaphragm should be visible to the spine and the vertebrae should be visible behind the heart

PA view of CXR

PA CXR is a standard front chest XR that uses XR beam to image the chest from back to front, and is the best general xray for examining heart, lungs, and other structures of the chest

PA technique of CXR

the patient stands facing a flat surface with their chest against the xray film--> the patient holds their arms up or to their sides and rolls their shoulders forward--> the xray beam passes through the patient from back to front --> the patient inhales deeply to fill their lungs

when do we perform an AP CXR?

In ICU, OR, Pt room; when patient is too sick to stand up or leave their bed

AP technique of CXR

patient lies on their back or is partly upright --> x ray tube is placed in front of patient's chest--> x ray film or detect panel is placed behind chest

Difference between AP and PA views of CXR

PA: scapula is seen in periphery of thorax, clavicles project over lung fields, posterior ribs are distinct, position of markers

AP: scapulae are over lung fields, clavicles are above the apex of lung fields, position of markers, anterior ribs are distinct

What are limitations of the AP CXR?

Heart side- heart appears larger and mediastinum appears more prominent

Lung bases- position limits depth of respiration which can limit evaluation of lung bases

Rotation: patients may be slightly rotated which can affect interpretation of the mediastinum

CXR lateral technique

Patient is standing, left side of thoraxx is adjacent to the image receptor, both arms raised above the head, preventing superimposition over the chest, chin raised out of image field, midsagittal plane must be perpendicular to divergent beam

Lateral CXR is most commonly ordered with what?

PA image

Advantages and disadvantages of decubitus CXR

A: allows for better visualization of fluid or air in the lungs, useful to determine the extent of loculation of fluid or air, can detect smaller amounts than upright CXR

D: uncomfortable for patient, may be difficult to interpret if patient is malpositioned

Technique of decubitus CXR

patient is lying on their side, for pneumothorax the side of interest should be up, for pleural effusions the side of interest should be down

Applications of CT

CT enables direct imaging and differentiation of soft tissue structures like liver, lung tissue, and fat. Therefore, it is a valuable tool in searching for large space occupying lesions, tumors, metastasis. They can not only reveal the presence but also the size, location, and extent of a tumor

CT Indications

To evaluate abnormalities shown on CXR. To demonstrate or exclude a suspected CXR abnormality. To demonstrate an abnormality in a patient with a normal CXR

CT contraindications

pregnancy, excessive, radiation exposure, contrast contraindication (iodine sensitivity, shellfish allergy, kidney disease)

Pathology of Pneumothorax

spontaneous, traumatic, iatrogenic, tension, extension of mediastinal air, air leak followign resection, bronchopleural fistula

History of pneumothorax

Most often presents with sudden onset of dyspnea and pleuritic chest pain, usually felt unilateral but in rare cases central or bilateral. Symptoms usually develop wen the patient is at rest, but sometimes can develop during exercise, air travel, invasive procedure or trauma to the chest, neck, gut, abdomen. Typical age is early 20s for a spontaneous pneumo

Pneumothorax PE

If small, findings may not evident.

If large, characteristic findings include decreased chest excursion on the affected side, enlarged hemothorax on the affected side, diminished breath sounds, absent tactile or vocal fremitus, hyper resonant percussion, as well as subq emphysema

labored breathing or accessory muscle use suggests sizable pneumothorax

tracheal deviation late sign of tension pneumo

hemodynamic compromise is ominous sign of tension pneumothorax or impending cardiopulmonary collapse

Tension PTX pathophysiology

A tension pneumothorax arises when air in the pleural space builds up enough pressure to interfere with venous return, leading to hypotension, tachycardia and severe dyspnea

Traditional teaching suggested that contralateral shift of the trachea and mediastinum, splaying of the ribs, and flattening of the ipsilateral diaphragm represent radiographic tension. However, these findings may result from atmospheric intrapleural pressure on the side of the pneumothorax while the pleural pressure on the contralateral side remains negative. Clinical evidence of tachycardia, hypotension, and severe dyspnea is more indicative of tension

Signs of a pneumothorax

deep sulcus

Needle decompression for a tension pneumothorax (traditional vs modern)

traditional: 2nd intercostal space in the midclavicular line. Difficulty finding the correct anatomical site, often times going too medially. 14g angiocath will fail to reach the chest cavity in more than 50% of cases

Modern: 4th or 5th intercostal space in the anterior axillary line. Chest wall is thinner making it easier to reach chest cavity. Less vital structures that could be injured. Easier to identify correct anatomical landmarks

Diagnostic imaging for pneumothorax

CT, CXR, US

US findings for pneumothorax

Lung sliding, comet tails (vertical artifact)

One CT scan is the same number of ____ CXR

200

US sensitivity and specificity

US sensitivity is 86-90% and specificity is 97-100%

What is the lung point in a pneumothorax US

the interface of where the healthy lung starts and where the pneumothorax ends

What is M mode in pneumothorax US?

seashore appearance in normal lung but barcode appearance in pneumothorax due to absence of lung movement

What is pleural thickening on CXR

Pleural thickening is a buildup of scar tissue in the lining around the heard, caused by inflammation, infection, lung disease, or malignancy. It is more common in men, smokers, and tall pts with low body weight. Appears on a chest X-ray as an irregular density or stripe at the lung's apex or deformed areas at top of lung

What are pleural plaques and when do we see this?

Pleural plaques are caused by asbestos fibers where they become trapped in the pleura, leading to inflammation and scarring

What is a Pancoast tumor?

This is a soft tissue opacity or mass in the apex of the lung. You may also find asymmetry of the lung apices, thickening of the pleura, local rib destruction, tracheal deviation, mediastinal enlargement. Symptoms include severe shoulder and arm pain, horners syndrome, atrophy of the intrinsic hand muscles. Additional testing is needed: CT, MRI, PET

rib fracture on CXR

Subcutaneous emphysema patho

injury to the parietal pleura that allows for the passage of air into the pleural and subq tissues. The air from the alveolus spreads into the endovascular sheath and lung hilum into the endothoracic fascia. The air in the mediastinum spreads into the cervical viscera and other connected tissue planes. The air originates from external sources. Gas generation locally by infections, usually necrotizing infections

Normal volume of pleural fluid

0.1-0.2 ml/kg

Pleural effusion causes

sterile, infection, inflammatory, malignant, chylothorax, diaphragmatic injury, biliary fistula, Boerhaave syndrome

Sx of Pt with pleural effusion

dyspnea, cough, chest pain, weakness, fever, weight loss, hemoptysis, recent trauma, cardiac surgery, cancer dx

PE of someone with pleural effusion

Signs are closely related to the size of a pleural effusion. Labored breathing or accessory muscles used in LARGE effusions. Decreased or absent tactile fremitus, dullness to percuss, diminished breath sounds over site of effusion. bronchial breath sounds are frequently present immediately above the effusion

Buzzword for pleural effusion on CXR

formation of a meniscus

In the average person, the diaphragm should be intersected by the __ and __ anterior ribs at the midclavicular line

5th and 7th

How many ribs are viewable on the PA inspiratory film

10

In what condition will you see an increase in number of viewable ribs

COPD or foreign body aspiration (hyperinflation)

In what condition will you see a decrease in number of viewable ribs

RLD, pleural effusions, atelectasis (under expansion)

Parenchymal crowding can mimic the appearance of what on a CXR

ILD

In a hiatal hernia what may you see

retrocardiac air fluid level within a paraoesophageal hernia or intrathoracic stomach

Ruptures diaphragm

sensitivty of reuptured diaphragm

pneumonia

bacterial pneumonia on CXR

viral pneumonia on CXR

aspiration pneumonia on CXR

Atelectasis

Signs of atelectasis

lobar atelectasis

segmental atelectasis

subsegmental atelectasis

Right lung collapse in a PA view

Cavitation on CXR

Causes of cavitation

Features of cavitations

What can cavitations be from?

Cavitations are an incidation for _____

CT scan

How does pleural effusion look on CXR

Hemothroax is indistinguishable from