Diagnostic Testing and Imaging Flashcards
BRONCHOSCOPY gives direct visualization of what? 3
Can be used to sample and treat lesions or abnormalities such as ?
3
Direct visualization of the
- trachea,
- bronchi, and
- segmental airways out to the third generation of branching
- foreign bodies,
- bleeding, tumors, or
- inflammation in those airways.
What things may it cause (3) and who is it contraindicated in (2)?
May cause
- tachycardia,
- bronchospasm, or
- hypoxemia.
Contra-indicated in patients with cardiac problems or severe hypoxemia
Diagnostic Indications for Bronchoscopy
11
- Cough
- Hemoptysis
- Wheeze
- Atelectasis/Accumulated secretions
- Unresolved Pneumonia
- Positive cytology
- Biopsy of suspicious tissue
- Abnormal CXR
- Bronchial obstruction
- Diffuse lung disease
- Pre/post intubation
Therapeutic Considerations for bronchoscopy?
6
- Foreign bodies
- Accumulated Secretions
- Atelectasis
- Aspiration
- Lung abscess
- Control of bleeding
DIRECT LARYNGOSCOPY AND RIGID BRONCHOSCOPY: advantages over flexible bronchoscopy? 2
- Better control of the airway
2. Easier to deal with large lesions, foreign bodies
Disadvantages of rigid bronchoscopy
2
- Requires general anesthesia
2. Higher rate of tissue damage/complications
Absolute contraindications for rigid bronchoscopy? 5
- Absolute – inability to adequately oxygenate the patient during procedure
- Coagulopathy or bleeding diathesis that cannot be corrected.
- Aneurysm, marked kyphosis.
- Recent MI or unstable angina.
- Respiratory failure requiring mechanical ventilation.
Complications of rigid bronchoscopy?
4
- Injury to the teeth
- Hemorrhage from the biopsy site
- Hypoxia and cardiac arrest
- Laryngeal edema
What is a major benefits of flexible bronchospy?
Mainly used for what kind of purposes?
- Does not require general anesthesia
- Limited intervention (e.g. suctioning)
- Can be used for intubation
Limited airway control
Mainly for diagnostic purposes
Can do biopsy, minor cautery
Very few complications in healthy patients
What is beneficial about flexible fiber optic bronscospy?
5
What do we want to do along with this?
- Provides magnification and better illumination.
- Smaller size –permits examination of subsegmental bronchi
- Easy to use in patients with neck or jaw abnormalities
- Can be performed under topical anesthesia & useful for bedside examination of critically ill patients
- Can be easily passed through endotracheal tube or in tracheostomy opening.
Suctioning of biopsy channel helps to remove secretions, inspissated mucus plug and small foreign bodies.
Who do we not use flexible fieber optic bronscospy with and why?
Limited utility in children –problem of adequate ventilations
What is a VIRTUAL BRONCHOSCOPY?
Benefits? 3
Downsides? 1
Computer generated pictures of the endobronchial tree, which are constructed from computed tomography (CT) images of the thorax
- Non-invasive,
- fine detail, and also
- provides information about structures outside of the airways
Cannot use for biopsy or treatment
Limitations of a chest x-ray
4
- 2 dimensional image of a 3 dimensional structure
- X-ray findings may lag behind other clinical features
- Normal x-ray does not rule out pathology
- Dependent on good quality image
The images seen on a chest radiograph result from what?
the differences in densities of the materials in the body.
The hierarchy of relative densities from least dense (dark on the radiograph) to most dense (light on the radiograph) include:
5
- Gas (air in the lungs)
- Fat (fat layer in soft tissue)
- Water (same density as heart and blood vessels)
- Bone (the most dense of the tissues)
- Metal (foreign bodies)
Three Main Factors Determine the Technical Quality of the Radiograph
Inspiration
Penetration
Rotation
The chest radiograph should be obtained with the patient in ______ ________ to help assess intrapulmonary abnormalities.
full inspiration
At full inspiration, the diaphragm should be observed at about the level of the_______ posteriorly, or the _______ anteriorly.
8th to 10th rib
5th to 6th rib
On a properly exposed chest radiograph:
The lower thoracic vertebrae should be visible through the _____?
The bronchovascular structures behind the heart should be seen. What are these?
3
heart
- trachea,
- aortic arch,
- pulmonary arteries,
What is the issue in an underexposed chest X-ray?
2
What pathology might it look like?
the cardiac shadow is opaque, with little or no visibility of the thoracic vertebrae.
The lungs may appear much denser and whiter, much as they might appear with infiltrates present.
What is the issue in an overexposed chest X-ray?
What pathology might it look like?
With greater exposure of the chest radiograph,
- the heart becomes more radiolucent and
- the lungs become proportionately darker.
In an overexposed chest radiograph, the air-filled lung periphery becomes extremely radiolucent, and often gives the appearance of lacking lung tissue, as would be seen in a condition such as emphysema.
Patient rotation can be assessed by observing what?
the clavicular heads and determining whether they are equal distance from the spinous processes of the thoracic vertebral bodies.
Four major positions are utilized for producing a chest radiograph. What are they?
Posterior-anterior (PA)
Lateral
Anterior-posterior (AP)
Lateral Decubitus
The standard position for obtaining a routine adult chest radiograph is what?
How are they positioned? 2
The pt is breathing how for the pic to be taken?
How should it be viewed?
PA
Patient
- stands upright with the anterior chest placed against the front of the film
- The shoulders are rotated forward enough to touch the film, ensuring that the scapulae do not obscure a portion of the lung fields
Usually taken with the patient in full inspiration
The PA film is viewed as if the patient is standing in front of you with his/her right side on your left
What does the lateral view allow to be seen?
How are they positioned?
Usually ordered with what?
Allows the viewer to see behind the heart and diaphragmatic dome
Patient stands upright with the left side of the chest against the film and the arms raised over the head
usullay ordered with a PA
When is AP used?
How are they positioned?
What do you have to remember about the film?
Whats usually seen in the lung field?
Used when the patient is debilitated, immobilized, or unable to cooperate with the PA procedure
The film is placed behind the patient’s back with the patient in a supine position
Because the heart is a greater distance from the film, it will appear more magnified than in a PA
The scapulae are usually visible in the lung fields because they are not rotated out of the view as they are in a PA
When is the LD used?
How are they positioned?
How is the xray labeled?
Often useful in revealing a pleural effusion that cannot be easily observed in an upright view, since the effusion will collect in the dependent position
The patient lies on either the right or left side rather than in the standing position as with a regular lateral radiograph
The radiograph is labeled according to the side that is placed down (a left lateral decubitus radiograph would have the
patient’s left side down against the film)
Anatomical Structures in the Chest
7
- Mediastinum
- Hilum
- Lung Fields
- Diaphragmatic Domes
- Pleural Surfaces
- Bones
- Soft Tissue
What should be centrally loctaed in the mediastinum?
What is the first convexity on the left side of the mediatstim?
What is the next convexity on the left?
What lies above the right heart border?
The trachea should be centrally located or slightly to the right
The aortic arch is the first convexity on the left side of the mediastinum
The pulmonary artery is the next convexity on the left, and the branches should be traceable as it fans out through the lungs
The lateral margin of the superior vena cava lies above the right heart border
How much of the heart lies on the right and left side?
The heart should take up how much of the thoracic cavity?
What creates the left heart border?
What creates the right heart border?
Two-thirds of the heart should lie on the left side of the chest, with one-third on the right
The heart should take up less that half of the thoracic cavity (C/T ratio less than 50%)
The left atrium and the left ventricle create the left heart border
The right heart border is created entirely by the right atrium (the right ventricle lies anteriorly and, therefore, does not have a border on the PA)
Both lungs should be scanned starting where and ending where?
Both lungs should be scanned, starting at the apices and working downward, comparing the left and right lung fields at the same level (as is done with auscultation)
On a PA radiograph, the minor fissure can often be seen as a faint horizontal line dividing the what from the what?
The major fissures are not usually seen on a PA view because they are being viewed ____?
RML from the RUL.
obliquely
The left dome is normally slightly lower than the right due to elevation by the _____ located under the right hemidiaphragm.
The costophrenic recesses are formed by the _____ and _______.
liver
hemidiaphragms and the chest wall
The pleura and pleural spaces will only be visible when there is a what?
Examples? 3
abnormailty present
pleural thickening, or fluid or air in the pleural space.
_______due to obesity may obscure some underlying structures such as lung markings?
thick soft tissue
The bones visible in the chest radiograph include what?
5
Ribs Clavicles Scapulae Vertebrae Proximal humeri
What is a siloutte sign?
Commonly seen with the borders of the what? 4
The loss of the lung/soft tissue interface due to the presence of fluid in the normally air-filled lung
heart, aorta, chest wall, and diaphragm
What is an Air Bronchogram?
Conditions in which air bronchograms are seen?
6
A tubular outline of an airway made visible due to the filling of the surrounding alveoli by fluid or inflammatory exudates
Lung consolidation Pulmonary edema Non-obstructive pulmonary atelectasis Interstitial disease Neoplasm Normal expiration
What is consolidation?
This dense material may consist of what?
4
The lung is said to be consolidated when the alveoli and small airways are filled with dense material.
This dense material may consist of:
- Pus (pneumonia)
- Fluid (pulmonary edema)
- Blood (pulmonary hemorrhage)
- Cells (cancer)
What is atelectasis?
Almost always associated with a linear increased density due to volume loss
Indirect indications for atelectasis of volume loss include?
- vascular crowding or
- mediastinal shift toward the collapse
- Possible observance of hilar elevation with an upper lobe collapse, or
- a hilar depression with a lower lobe collapse
Typical findings on the chest radiograph for pneumonia include:
3
Airspace opacity
Lobar consolidation
Interstitial opacities
What will a plueral effusion look like on an upright film?
On an upright film, an effusion will cause blunting on the lateral costophrenic sulcus and, if large enough, on the posterior costophrenic sulcus.
How many ml are needed to detect an effusion on a PA film?
In a lateral view?
How will it appear on an AP film?
A lateral decubitus film?
Approximately 200 ml of fluid are needed to detect an effusion in a PA film, while approximately 75 ml of fluid would be visible in the lateral view
In the AP film, an effusion will appear as a graded haze that is denser at the base
A lateral decubitus film is helpful in confirming an effusion as the fluid will collect on the dependent side
A pneumthorax appears in a chest radiograph how?
In a PA film it is usually seen where?
The air is typically found peripheral to the ?
When should we take the XRAy in breathing cycle?
Appears in the chest radiograph as air without lung markings
In a PA film it is usually seen in the apices since the air rises to the least dependent part of the chest
The air is typically found peripheral to the white line of the visceral pleura
Best demonstrated by an expiration film
There are two basic types of pulmonary edema. What are they and caused by?
Cardiogenic pulmonary edema caused by increased hydrostatic pulmonary capillary pressure
Noncardiogenic pulmonary edema caused by either altered capillary membrane permeability or decreased plasma oncotic pressure
Common features observed on the chest radiograph of a CHF patient include:
4
- Cardiomegaly (cardiothoracic ratio > 50%)
- Cephalization of the pulmonary veins
- Appearance of Kerley B lines
- Alveolar edema often present in a classis perihilar bat wing pattern of density
Common features seen on the chest radiograph for emphysema include?
4
- Hyperinflation with flattening of the diaphragms
- Increased retrosternal space
- Bullae
- Enlargement of PA/RV (cor pulmonale)
A lung mass will typically present as a what?
lesion with sharp margins and a homogenous appearance, in contrast to the diffuse appearance of an infiltrate.
Measurements called Hounsfield Units are used to differentiate what in CT scans? 4
Bone is what value?
Fat is what value?
What can cause distortion of the image?
- cysts,
- lipomas,
- hemochromatosis,
- vascular and avascular lesions
Bone is +1000, water is 0, fat is -1000 and other tissues fall within this scale
Metal and barium can cause distortion of the image
What are the benefits of a chest CT?
- Depicts more nodules than plain CXR
- Useful in differentiating hilar adenopathy from vascular structures seen on plain CXR, especially when contrast-enhanced images are obtained.
- High resolution images are useful for characterizing interstitial lung disease
Standard CT: Slice thickeness? Scans what kind of volume and at what speed? Covers what area? Contrast?
Indications?
5
Slice thickness: 3-10 mm
scans a large volume, very quickly
Covers the full lung
+/- contrast
Indications
- CXR abnormality
- Pleural and mediastinal abnormalities
- Lung cancer staging
- F/U metastases
- Empyema vs abscess
HIGH RESOLUTION (HRCT):
Describe the xray beam calumniation.
What kind of structures does it show? 4
Contrast?
Indications?
9
narrow x-ray beam collimation: 1-1.3mm vs. conventional 3-10mm cross sections are further apart: 10 mm high definition images of lung parenchyma: 1. vessels, 2. airspaces, 3. airway and 4. interstitium No contrast
- Hemoptysis
- Diffusely abnormal CXR
- Normal CXR with abnormal PFTs
- Baseline for patients with diffuse lung disease
- Solitary pulmonary nodules
- Reversible (active) vs. non-reversible (fibrotic) lung disease
- Lung biopsy guide
- F/U known lung disease
- Assess treatment response
Low dose CT:
Why do we use it?
Indications?
6
Premise: lower dose radiation will not reduce the diagnostic functionality of the scan (eg. 250 mAs 50 mAs)
Detail is decreased
Uses
- Screening (example…smokers/former smokers)
- ongoing trials
- F/U
- infections
- post lung transplant
- metastases
Angiography (CTA)
Where is the contrast injected?
Indications? 3
Risks? 2
- -contrast injected into peripheral vein
- injection timing/rate controlled automatically
- Pulmonary embolism
- Aortic aneurysms
- Aortic dissection
Risks
- Iodinated contrast:
- Allergic/ nephrotoxic
Benefits of a spiral CT?
Useful in the diagnosis of what?
4
Minimizes motion artifact and allows capture of a bolus of contrast material at peak levels in the region being scanned
Useful in dx of
- PE,
- evaluation of flank pain,
- detection of kidney stones and 4. rapid evaluation of trauma
COMMON PATHOLOGIC FEATURES ON CHEST CT
7
- Air Bronchograms
- Bronchiectasis
- Septal Thickening
- Ground Glass Opacity
- Emphysema
- Nodules
- Filling Defect
What is a V/Q (ventilation/perfusion) SCAN?
What does each part evaluate? 2
Who is it a preferred test in?
A type of medical imaging using scintigraphy to evaluate the circulation of air and blood within a patient’s lungs
- The ventilation part of the test looks at the ability of air to reach all parts of the lungs
- The perfusion part evaluates how well blood circulates within the lungs.
pregnant women
Indications for V/Q (ventilation/perfusion) SCAN?
6
Most commonly done to diagnose or rule out
- presence of a blood clot or
- abnormal blood flow inside the lungs.
- PE
- COPD
- Pneumonia
- Post lobectomy
What is the Virchow triad?
3
Pulmonary Embolism Pathophysiology:
- Hypercoagulability
- Stasis to flow
- Vessel injury
Risk factors for PE:
Hypercoagulability? 4
Venous Stasis? 3
Venous injury? 2
Hypercoagulability
- Malignancy
- Pregnancy
- Postpartum status (less than 4wk)
- Estrogen/ OCPs
Venous Stasis
- Recent cast or external fixator
- Long-distance travel or prolong automobile travel
- Bed rest > 24 hr
Venous Injury
- surgery
- trauma (especially the lower extremities and pelvis)
Presentation of PE?
4
- Dyspnea
- Pleuritic chest pain
- Low-grade fever
- Tachycardia
What is the Westermarck’s sign?
Whats is the Hampton’s Hump?
Westermarck’s sign
A dilation of the pulmonary vessels proximal to the embolism along with collapse of distal vessels, sometimes with a sharp cutoff.
Hampton’s Hump
A triangular or rounded pleural-based infiltrate or consolidation with the apex toward the hilum.
Results for a normal perfusion scan?
What about for a low probability V/Q scan?
High probability V/Q scan:
Intermediate probability V/Q scan:
means that the patient is very unlikely to have acute PE.
means that the patient has less than 20% probability of having acute PE.
means that the patient has greater than 80% probability of having acute PE.
means that the patient has between 20 – 80% probabilities of having acute PE.
Relative contraindications for VQ?
2
- Pulmonary Hypertension
2. Right to Left shunts e.g. VSD.
Spiral (Helical) Chest CT and PE:
Advantages? 2
Disadvantages? 4
Advantages
- Rapid
- Alternative Diagnosis
Disadvantages
- Costly
- Risk to patients with borderline renal function
- Hard to detect subsegmental 4. pulmonary emboli
Why dont we use a pulmoonary angiography for PEs often even though they are 100% effective in finding an obstruction?
Its super invasive
