Thoracic Imaging

Question 1

Define attenuation (x-rays).

Answer 1

reduction of x-ray beams through different substances

bone blocks most = white; air blocks least = black

Question 2

Define scatter (x-ray)

Answer 2

Reflection of radiation beam

Question 3

What are the key differences between antero-posterior (AP) CXR & postero-anterior (PA) CXR & lateral CXR?

Answer 3

• AP: is bedside & sloppy
• PA: pt erect & controlled environment
• Lateral is similar to PA (adds second dimension)

(PA + lateral = PA Lateral best view of chest)

Question 4

AP films make the heart look _____.

Answer 4

bigger

(casts wider shadow on film; important structures further from “camera”)

Question 5

In PA films, the heart should be < 50% total _______.

(shot through the back; most important structures are closer to “camera”)

Answer 5

transthoracic diameter

(AP it is >50%)

Question 6

Pulmonary Surface Anatomy. Name the structures.

Answer 6

Question 7

Right lateral pulmonary surface anatomy. Name the structures.

Answer 7

(listen to all 3 spots laterally)

Question 8

Left lateral pulmonary surface anatomy. Name the structures.

Answer 8

(listen to both spots laterally)

Question 9

List the order of evaluation on PA Chest films (10).

Answer 9

1. Patient data (name, hx, age, sex)
2. Clavicles, sternum, vertebrae, shoulders and rib fx
3. trachea, carina, R & L bronchi
4. Hila
5. Mediastinum
6. Heart
7. Lungs
8. Pleura
9. Diaphragms
10. Stomach

(ICU: Must ID tubing)

Question 10

List the order of evaluation for lateral chest films (6).

Answer 10

1. Clavicles
2. Trachea/mainstem bronchi
3. Heart
4. Lung fields
5. Retrosternal space
6. Diaphragms

Question 11

PA CXR is done from ______ inches away. AP is done from _____ inches away.

Answer 11

• 72
• 40

Question 12

Diaphragm is found at the ______ level of the posterior ribs or the ______ level of the anterior ribs.

Answer 12

• 8-10th
• 5-6th

Question 13

In a PA CXR, why is the left side of the chest against the film?

Answer 13

minimizes LV enlargement

Question 14

Why is it important for the patient to take a deep inhale and hold it for a CXR?

Answer 14

loss of R heart border silhouette looks like pneumonia

(left: poor inspiration looks like pneumothorax, but its just overpenetrated; right: same pt done correctly)

Question 15

What are signs of adequate penetration on PA CXR?

Answer 15

1. T spine discs barely visible
2. vertebrae details not visible
3. bronchovascular structures seen through heart

Question 16

What are signs of adequate penetration on lateral CXR?

Answer 16

spine appears to darken as you move caudally

(more air in lower lobes of lungs)

Question 17

What do these XR represent

Answer 17

Left: underpenetrated PA film

Right: overpenetrated PA film

Question 18

What is the consequence of rotated clavicular heads on CXR?

Answer 18

mediastinum appears wider

(if rotated, the heads will not be equidistant from the spinous process)

Question 19

Answer 19

Lateral CXR shows right ribs that appear larger due to magnification (red arrow); left ribs more prominent and anterior

Question 20

Answer 20

Question 21

Answer 21

Question 22

Answer 22

Question 23

Answer 23

Question 24

Answer 24

(lingula is the "physiological 3rd lobe" of the L lung -->effusion here)

Question 25

Define Silhouette sign

Answer 25

elimination of the silhouette (loss of lung/soft tissue interface) due to mass or fluid in the normally air-filled lung

Question 26

Answer 26

Question 27

Answer 27

Question 28

Answer 28

silhouette sign: left lingular lobe (lingula apples to the anatomical equivalent: portion of L upper lobe that borders the heart and has superior & inferior segments)

Question 29

Answer 29

Air Bronchogram: tubular outline of airway (visible due to fluid/infiltrates)

Question 30

6 causes of air bronchograms

Answer 30

1. lung consolidation 2. pulmonary edema 3. nonobstructive pulmonary atelectasis 4. severe interstitial disease 5. neoplasm 6. normal expiration

Question 31

What is this called? What would make these suspicious for cancer?

Answer 31

solitary pulmonary nodule: irregular (stippled, spiculated) calcifications (if unchanged for 2 years → benign ; \< 1 cm benign; make note of the “bamboo” spine: fused by autoimmune condition)

Question 32

Answer 32

Retrocardiac pulmonary tumor on lateral CXR

Question 33

One of the MC findings on CXR which is most often benign secondary to prolonged bed rest/post surgical

Answer 33

atelectasis

Question 34

Answer 34

Kerley B Lines: upward sloping horizontal lines \< 2 cm long; thickened, edematous interlobular septa (atelectasis is downward sloping)

Question 35

Causes of Kerley B lines (7) (white dashed lines)

Answer 35

1. pulmonary edema 2. lymphangitis carcinomatosis 3. malignant lymphoma 4. viral & mycoplasma pneumonia 5. interstitial pulmonary fibrosis 6. pneumonoconiosis 7. sarcoidosis

Question 36

Answer 36

Question 37

What are the causes of this?

Answer 37

pneumonia: virus, bacteria, fungus, mycoplasma (airspace consolidation disease; filled w/pus & microorganisms)

Question 38

How many ounces of fluid are needed to visualize this on CXR?

Answer 38

* pleural effusion * 200 mL

Question 39

When are decubitus CXR films taken?

Answer 39

detects pleural effusion (infiltrates won't move with gravity; they're “loculated”)

Question 40

Define pneumothorax

Answer 40

air inside the thoracic cavity but outside the lung

Question 41

Define tension pneumothorax

Answer 41

air enters pleural cavity & is trapped during expiration → increases intrathoracic pressure (this can compromise venous filling of heart → death)

Question 42

Pneumothorax is best demonstrated by _____.

Answer 42

full expiration of breath (note the lack of lung markings at the apex)

Question 43

Answer 43

interstitial pulmonary fibrosis: hazy “ground glass” opacification early; late: volume loss w/linear opacities bilaterally & honeycomb lung (restrictive)

Question 44

Prognosis?

Answer 44

3-6 years to live unless lung transplant

Question 45

Answer 45

Emphysema: loss of elastic recoil

Question 46

Describe the common visual keys to emphysema on CXR (7)

Answer 46

1. diffuse hyperinflation w/flattening/tenting of diaphragms 2. increased retrosternal space 3. thoracic kyphosis 4. elongated lung fields past the 10th rib 5. bullae 6. vertical elongation of the heart 7. RA/RV enlargement

Question 47

make note of pulmonary edema and interstitial fibrosis differentiate the two.

Answer 47

.