Basics of X-ray interpretation Flashcards
1
Q
The overall quality of a film is better if it is taken ___ (PA vs AP)
A
The overall quality of a film is better if it is taken PA (PA vs AP)
2
Q
A
2 - R mainstem bronchus
3 - L mainstem bronchus
4 - L pulmonary artery
5 - RUL pulmonary vein
6 - R Interlobar artery
7 - R pulmonary vein
8 - Aortic arch
9 - SVC
10 - Azygos arch
3
Q
The AP window
A
The space between the aortic arch (8) and the L pulmonary artery (4)
This should be concave. If it is filled in or convex, this indicates a likely aortic dissection.
4
Q
Anatomy superimosed over lateral CXR
A
- Trachea
- Bronchus intermedius
- LUL bronchus
- RUL bronchus
- L pulmonary artery
- R pulmonary artery
- Pulmonary vein confluence
- Aortic arch
- SVC
5
Q
The __ hemidiaphragm is usually higher than the __ hemidiaphragm on CXR
A
The R hemidiaphragm is usually higher than the L hemidiaphragm on CXR
6
Q
Systematic approach to reading an AP/PA CXR
A
- Identify lines and tubes – ensure proper positioning
- Heart - borders, size, position, calcifications, gas
- Mediastinum and Trachea
- Lungs – close and far, costophrenic angles
- Abdomen and Stomach
- Bones and soft tissues
- Final checkpoints (frequently missed things)
- Lung apices
- Hila
- Retrocardiac
- Retrodiaphragmatic
7
Q
Most vasculature in the lungs should be. . .
A
. . . in the medial third of the lungspace
There should be none or next to none in the perihperal third
8
Q
Way to tell if the patient is rotated on CXR
A
Compare the medial aspects of the clavicles to the spinous processes
The spinous process should be roughly halfway between the medial aspects of the clavicles
9
Q
How to tell if the patient had a good inspiration during a CXR
A
Should see at least 8-9 posterior ribs
10
Q
Systematic approach to reading a lateral CXR
A
- Retrosternal space
- Retrocardiac area
- Spine sign
- Hila
- Costophrenic angles
- Heart
11
Q
Five technical factors of a chest radiograph to evaluate before interpreting
A
- Penetration
- Inspiration
- Rotation
- Magnification
- Angulation
12
Q
Magnification of the heart
A
The heart shadow is larger on an AP film than on a PA film (ie, larger on portable x-rays)
13
Q
Effects of poor inspiratory effort
A
Poor inspiratory effort will compress and crowd the lung markings, especially at the bases of the lungs near the diaphragm.
This may lead you to mistakenly think the study shows lower lobe pneumonia. To avoid this error, look at the lateral chest radiograph to confirm the presence of pneumonia
14
Q
Positioning of the patient for X-ray imaging
A
15
Q
Result of an apical lordotic radiograph
A
16
Q
Five checkpoints on the lateral radiograph
A
- Retrosternal clear space
- Hilar region
- Fissures (may not be visible)
- Thoracic spine / retrocardiac space
- Diaphragm and posterior costophrenic sulci
17
Q
Retrosternal space on a lateral radiograph
A
This picture shows a comparison of normal (left) to anterior mediastinal lymphoma (right)
18
Q
Arms in the retrosternal clear space
A
You can tell if the opacity you see in the retrosternal clear space is an arm by looking for the humeri and then following out the skin folds
19
Q
Course of the major fissures
A
Fifth thoracic vertebra to a few cm behind the sternum
20
Q
Course of the minor fissure
A
At the level of the fourth anterior rib on the right side only
21
Q
How can you tell if thickening of the fissure lines is due to fluid or fibrosis?
A
Thickening of fissure lines due to fluid never occurs in isolation – there will be other signs of fluid on the radiograph.
In comparison, thickening due to fibrosis is often isolated.
22
Q
Spinal degeneration
A
This image shows spinal degeneration due to osteoporosis
The black arrow highlights the eighth thoracic vertebra, which has lost stature.
The white arrows point to osteophytes at the vertebral margins due to degenerative disc disease.
23
Q
Volume required to blunt frontal vs lateral costophrenic angles
A
Frontal: 250-300 mL
Lateral: ~75 mL
24
Q
Bronchus artery relationship
A
The normal relationship between the bronchus (solid white arrow) and its accompanying pulmonary artery (dotted white arrow) is that the artery is usually larger than the bronchus.
In bronchiectasis, that relationship is reversed with the bronchus becoming larger than the artery (signet-ring sign)
25
What is the first thing to do after looking at a chest X-ray?
Look at an old chest X-ray
26
You can basically diagnose ___ by pulmonary lobule features on CT
You can basically diagnose **alpha1 antitrypsin deficiency** by pulmonary lobule features on CT
If only upper lobes, think smoking. If paraseptal, think idiopathic or
27
Spiculation on X-ray
Highly suggestive of lung cancer -- vascular supply
28
Air bronchogram
Bronchi which are still filled with air in a consolidation
Suggests bacterial PNA vs cancer
29
Pulmonary alveolar proteinosis
30
Allergic bronchopulmonary aspergillosis
Severe hypersensitivity to aspergillus
Causes severe dilation of proximal bronchi and impaction leading to bronchiectasis
31
What runs along the pulmonary septae?
The pulmonary venules and lymphatics
32
Kerley A and B lines on CXR
Kerley A lines are in the parenchyma and run straight, usually without branching (right side in this image)
Kerley B lines are along the side of the lung and run horizontally (left side in this image)
Both are due to increased pressure in the lymphatics along the pulmonary septae in this case, but may be seen in pulmonary fibrosis due to fibrotic infiltrate in the same space.
33
Peribronchial cuffing
Due to lymphatics along the bronchi dilating. Highlights the bronchi.
Also seen in CHF, but other cases as well.
34
The lingula of the left lung is part of which lobe?
The left upper lobe
35
In whom is a followup CXR for treated pneumonia indicated?
1. Any patient over age 40
2. Any patient with recurrent PNA
3. Any patient whose symptoms do noy resolve
36
Early COVID-19 PNA on CXR
. . . often can't be seen!
You can often only see the ground glass opacities of early COVID-19 on CT scan.
37
When it amy be appropriate to use CT instead of CXR for pneumonia diagnosis
1. Immunocompromised patient
2. Suspected early COVID-19 (however PCR test has made this less imporant!)
38
What is the best way to confirm the presence of a suspected pulmonary effusion unclear on AP CXR?
* Right lateral decubitus CXR (first line, but may not show loculated fluid)
* Other possibilities:
* Ultrasound (good alternative)
* CT (not typically used)
* MRI (not typically used)
39
It is very difficult to detect a pleural effusion on a __ radiograph
It is very difficult to detect a pleural effusion on a **supine** radiograph
40
It is okay for an internist or resident to tap a pleural effusion. It is not okay for them to tap \_\_\_.
It is okay for an internist or resident to tap a pleural effusion. It is not okay for them to tap **empyema.**
This is due to the risk for infection of other tissues. For this reason, the task is left to experts in radiology via ultrasound guidance.
Other cases where ultrasound guidance is required include effusions that are **small, loculated,** or the patient is at high risk for a pneumothorax, such as with **concurrent emphysema**
41
Two main indications for preoperative CXR
1. Acute cardiopulmonary findings on H&P
2. Chronic cardiopulmonary disease in adults over age 50 with no other CXR in the past 6 months
42
Lung cancer screening guidelines
* Ages 50-80 with \>20 pack year smoking history or current smoker
* If stopped \>15 years ago and asymptomatic, not indicated
* Annual low-dose CT
43
You have identified a 2 cm solitary pulmonary nodule and done a CT which did not reveal any other masses. What is the next step?
Usually **PET scan**, to assess for metabolic activity and for more difficult to detect metastases
Biopsies here are often not very helpful as benign lesions often have non-diagnostic biopsies, and there are risks involved with lung fine needle biopsy.
**If the PET scan is positive, biopsy is the next step.**
44
Contraindications for percutaneous lung biopsy
* Bleeding diathesis
* Pulmonary hypertension
* Severe emphysema
* Ventilated patient
* Central lesions
45
Imaging to assess for suspected small pneumothorax
1. Erect expiratory CXR
2. Right lateral decubitus CXR
46
Mangement of a small \<10%, asymptomatic pneumothorax
* Monitor for symptoms
* Repeat imaging 4 hours before discharge.
* If unchanged or smaller, discharge with instructions to return if symptoms and repeat imaging 1-2 days after discharge
47
Where do you place a needle in the emergent setting of tension pneumothorax?
2nd ipsilateral intercostal space at the midclavicular line
48
Aunt Minnie sign
Left upper lobe collapse
Just looks so distinctive. Nothing else like it. Stop saying what I type.
49
If you obstruct a bronchus. . .
. . . **the distal alveoli will collapse**
50
Types of interstitial pattern
**Reticular:** a network of lines (A)
**Nodular:** an assortment of dots (B)
**Reticulonodular:** both lines and dots (C)
In all cases, “Packets” of disease are separated by normal-appearing, aerated lung, and air bronchograms are never present.
51
Opacification with heart/trachea shift *towards, away,* and *not at all.*
Towards: Atelectasis
Away: Fluid/mass/space occupying lesion
Not at all: Pneumonia OR coexistence of the above
52
Compressive atelectasis
Caused by either poor inspiratory effort or secondary to a large pleural effusion, pulmonary edema, or space occupying mass.
In poor inspiratory effort, it will always be at the lung bases.
53
What is the most likely underlying cause of the process going on in this CXR?
Here there is an opacified hemithorax without movement of the mobile structures, and with no air bronchograms indicating a consolidative process like pneumonia. This suggests a balance of atelectasis and pleural effusion.
This is most concerning for a **central bronchogenic carcinoma producing obstructive atelectasis and metastases producing malingnant effusion.**
54
Round atelectasis
Form of compressive atelectasis is usually seen at the **periphery of the lung base** and develops from a combination of **prior pleural disease** (e.g., from asbestos exposure or tuberculosis) and the formation of a **pleural effusion** that produces adjacent compressive atelectasis.
When the pleural effusion recedes, the underlying pleural disease leads to a portion of the atelectatic lung becoming “trapped.” This produces a **mass-like lesion that can be confused for a tumor.** The white arrow points to "comet tails" which emanate from the apparent mass, demonstrating that it is actually atelectasis.
55
Obstructive atelectasis
Associated with the resorption of air from the alveoli, through the pulmonary capillary bed, distal to an obstructing lesion of the bronchial tree.
This produces consistently recognizable patterns of collapse. In general, lobes collapse in a **fan-like configuration** with the base of the fan-shaped triangle anchored at the pleural surface and the apex of the triangle anchored at the hilum.
It takes about **18 to 24 hours** for an entire lung to collapse with the patient breathing **room air** but less than **an hour** with the patient breathing **near 100% oxygen.**
56
On which side of the pleura is fluid produced vs resorbed?
Produced at the parietal pleura, resorbed at both the visceral and parietal pleura
57
Diseases that usually produce a *unilateral* pleural effusion
* TB, viral, bacterial, other infectious pneumonias
* Pulmonary embolism
* Trauma
58
Diseases that usually produce *specifically* a left sided pleural effusion
* Pancreatitis
* Distal thoracic duct obstruction
* Dressler's syndrome (2-3 weeks post myocardial infarction, often with pericardial effusion and fever as well)
59
Diseases that usually produce *specifically* a right sided pleural effusion
* **Hepatitis**
* **Meig's snydrome** (benign ovarian tumor, right sided pleural effusion, ascites)
* Rheumatoid arthritis
* Proximal thoracic duct obstruction
60
What can you do to better elucidate the etiology of a massive pleural effusion if you cannot visualize anything on conventional radiography?
Do a CT!
61
Given the pattern of disease, what is/are the likely causative organism(s)?
62
When are you likely vs unlikely to see air bronchograms in a pneumonia?
Likely: When the pneumonia involves the **central portion** of the lung or is **lobar/consolidative**
Unlikely: When the pneumonia is mostly **peripheral** or is **not lobar (segmental, interstitial)**
63
Common cavitating pneumonias
* **Mycobacterium tuberculosis** (usually post-primary, bilateral, thin-walled, and with no air fluid level)
* **Staphylococcal pneumonia** can produce post-infectious pneumatoceles (shown)
* Streptococcal pneumonia
* Klebsiella pneumonia
* Coccidiomycosis
64
Where is the pneumonia given which structure is blurred?
65
Where is the pneumonia in each of the images?
A: Right upper lobe
B: Right middle lobe
C: Right lower lobe
66
Pneumonia response to treatment
Great improvement in 2-3 days if sensitive to the appropriate antibiotic, but radiographic and exam evidence may remain for a couple of weeks.
If after ~1 month radiographic and exam evidence of improvement is not present, another underlying process such as malignancy should be suspected.
67
What are the radiographic signs of COPD?
* **Hyperinflation** (barrel chest, \>10 posterior ribs above diaphragm)
* **Flattening of hemidiaphragms** (best assessed on lateral film)
* **Increased lucency of lungs** (due to loss of vasculature)
* **Narrowing of the mediastinum**
* **Presence of bullae** (often apical)
* **"Saber sheath" deformity** of the trachea (best seen on CT)
68
What is the best test in the case of suspected aortic dissection?
**CT aortogram (w/ and w/o contrast)**
If the patient can tolerate iodinated contrast, that is.
Otherwise, **MRI with gadolinium** if stable. If unstable or MRI contraindicated, **TEE** is appropriate.
69
What an IVC filter looks like on x-ray
70
Kerley A, B, C
A: Always directed toward hila, not at the periphery
B: At the periphery, parallel with diaphragm
C: Randomly directed interstitial lines, but can't be seen on chest radiographs
71
Cardiothoracic ratio
On a PA film, \< 0.5 is normal
On an AP film, \< 0.6 is normal (enlarged cardiac shadow)
72
What structure is circled?
The right atrium
73
What structure is circled?
The right ventricle
74
What structure is circled?
The left ventricle
75
What structure is circled?
The left atrium
76
Location of the four valves on CXR
This patient with three valve replacement is an excellent example
77
Anterior mediastinal masses
78
What is the most frequently encountered anterior medisastinal mass?
**Substernal thyroid tissue**
On CT, these masses frequently continguous with the thyroid gland, contain calcifications, and enhance with contrast in a mottled but homogenous manner.
This diagnosis can be confirmed with a nuclear medicine iodine uptake scan
79
Anterior mediastinal lymphadenopathy is most characteristic of \_\_\_
Anterior mediastinal lymphadenopathy is most characteristic of **Hodgkin's lymphoma**
80
Sarcoid vs lymphoma on imaging
81
Middle mediastinal masses
Tend to interact with the midline mediastinal structures. Most masses in this compartment are due to lymphadenopathy, from malignant causes, lymphomas, infectious mononucleosis, or tuberculosis.
Shown is medial mediastinal lymphadenopathy due to small cell lung cancer which is pushing on the trachea posteriorly.
82
Middle mediastinal lymphadenopathy of tuberculosis is often ___ while middle mediastinal lymphadeopathy of infectious mononucleosis is often \_\_\_.
Middle mediastinal lymphadenopathy of tuberculosis is often **unilateral** while middle mediastinal lymphadeopathy of infectious mononucleosis is often **bilateral.**
83
The most common posterior mediastinal masses are . . .
. . . **tumors of neural origin** -- neurofibroma, Schwannoma, ganglioneuroma, neuroblastoma.
Schwannomas are the most common among these, and are benign. In contrast, ganglioneuromas and neuroblastomas are usually malignant.
84
Ways to tell that something is in the posterior mediastinum
* Posterior on a lateral film is highly suggestive
* **Erosion of posterior ribs**
* Localization along the paravertebral gutter
* "Dumbell sign" on CT -- the shape created by a tumor squeezing out of the neural foramina
85
Spine in NF1
* **"Scalloped" posterior vertebral bodies** are characteristic
* This is due to diverticula of the thecal sac caused by dysplasia of the meninges
* There is often also:
* **Rib notching** proximal to the spine
* **Absence of sphenoid wings**
* **Sharp-angled kyphoscoliosis**
86
"Solitary pulmonary nodule" vs "pulmonary mass"
Nodule must be \< 3 cm
Once it is \> 3cm, it is a mass
87
"Solid" vs "Subsolid" pulmonary nodule
Based on CT density
A here is a solid nodule.
B and C are both subsolid, but B is *pure ground glass* while C is *part solid-part ground glass*
As a rule of thumb: Pulmonary nodules that are **solid** and **unchanged** on serial CTs over a **two-year period**, or **subsolid** and **unchanged** over a **five-year period**, are likely benign and **do not need further diagnostic evaluation**
88
Nodule size and risk of malignancy
\< 5 mm -\> almost never malignant, even in smokers
\> 5 cm -\> 95% malignant no matter who they are in
89
Benign patterns of SPN calcification
* Central, laminar, and diffusely calcified lesions are invariably nonmalignant
* Of these, diffusely calficied lesions (A) are a hallmark of **TB granulomas**
* Meanwhile, central "target" calcifications (B) or laminar calcifications are a hallmark of **Histoplasmoma** (and are in fact diagnostic).
90
If you are unsure based on CXR and CT features whether a nodule is benign, the next step is. . .
. . . **FDG PET scan**
91
CT features of a pulmonary hamartoma
* Hamartomas are peripherally located tumors of disorganized lung tissue
* They characteristically contain **fat** and **calcifications**
* They are often referred to as **"popcorn calcifications"**
92
Squamous cell diagram
93
Adenocarcinoma diagram
94
Small cell diagram
95
Recognizing bronchogenic carcinomas
* Often have irregular, spiculated margins
* May cavitate (particularly squamous cell), and when they do will have thick walls and irregular margins
96
Bronchogenic carcinomas (SCLC, adeno, squamous) often present with. . .
. . . **bronchial obstruction**
97
Pancoast tumor
Note the associated rib destruction (black arrow) in comparison with the other side
98
Most common lung metastases in male vs female (all comers)
Male: Colorectal
Female: Breast
99
When should you be *highly suspicious* of lymphangitic carcinomatosis
**When on one *side* or one *lobe*** appears to have increased pulmonary pressure with the typical CHF findings (Kerley B lines, peribronchial cuffing, interstitial markings, etc)
100
Four cardinal findings of pulmonary interstitial edema
101
Three cardinal findings of pulmonary alveolar edema
102
Bowel under the right diaphragm
Can be simply due to a physiologic break in the liver tissue with colon underneath the diaphragm
A variant of normal
103
The large bowel has \_\_
The small bowel has \_\_
The large bowel has **haustrae**
The small bowel has **vulvae conneventies**
104
Pneumomediastinum
105
Radial head fracture
Radial head fx is the most common cause of elbow effusions with posterior and anterior fat pad elevation!
106
Lipohemarthrosis
