Chest

Question 1

CT scans of the chest for disease progression should extend inferiorly through what anatomy?

Answer 1

adrenal glands (a common site for metastatic deposit)

Question 2

For CT of the lungs/mediastinum, what would be the recommended kVp, mA, and slice thickness?

Answer 2

120 kVp, 40-300 mA, 3-5 mm slice thickness

Question 3

What are sample WL and WW for lung parenchyma, mediastinum, and bone?

Answer 3

parenchyma: WL -450, WW 1400
mediastinum: 40, 350
bone: 300, 2000

Question 4

For High Resolution CT of the lungs, what is a sample slice size and spacing?

Answer 4

thin slices of 1-2 mm; separated by 10-15 mm

Question 5

What is the primary indication for HRCT of the Lungs? What are some examples of that?

Answer 5

Diffuse lung disease:

Chronic Obstructive Pulmonary Disease (COPD), Emphysema, Cystic Fibrosis, and Asthma

Question 6

Patients with _________ can be scanned after full EXpiration.

Answer 6

air trapping (small airway disease)

Question 7

CT Pulmonary Angiography is commonly called what?

Answer 7

CTA PE

Question 8

For a CT Pulmonary Angiography study, what direction is the patient scanned? Why?

Answer 8

a. caudocranial
b. if pt cannot hold breathe for entire scan, streaking from lung movement is limited as the scan progresses superiorly; AND there is less streaking from the contrast in the SVC

Question 9

What is a sample technique for CTPA?

Answer 9

a. 120 kVp, 400 mA, 0.8 sec
b. 0.75 mm slice overlap
c. 0.625 mm collimation

Question 10

What is “Prospective Gating (Triggering)”?

Answer 10

when using a ECG, the heart rate is read and scans are only made during periods of diastole

Question 11

What is “Retrospective Gating”?

Answer 11

when using a ECG, scanning throughout the entire cardiac cycle and choosing which images to keep/recon based on the selected cardiac cycle

Question 12

What is a technical limitation of a Coronary Artery Calcium CT?

Answer 12

inability of CT to differentiate between calcium and noncalcified atherosclerotic plaque

Question 13

What portion of the ECG does scanning occur during a CT Calcium study?

Answer 13

during the T wave

Question 14

What minimum size and HU must a calclification be to be scored?

Answer 14

1 mm squared; 130+ HU

Question 15

What are the four levels of calcium scoring?

Answer 15

minimum: 1-10
mild: 11-100
moderate: 101-400
extensive: 401+

Question 16

What anatomy must be included on a CT Calcium Study?

Answer 16

the aortic arch through the cardiac base

Question 17

What heart rate yields the best results for a CT Calcium Study?

Answer 17

slow and steady; below 65-75

Question 18

What is temporal resolution? How is it related to gantry rotation time?

Answer 18

temporal resolution is how well the CT was able to “freeze” the motion of the heart and its arterial motions;
gantry rotation time describes the time for the gantry to make one rotation. example: if the GRT is 300 msec, the temporal resolution is 300 msec.

Question 19

What is Half-Scan Reconstruction for CT Calcium Study?

Answer 19

the gantry rotates fast enough to scan the entire heart in half of a rotation. Because of this, the temporal resolution would be half of one rotation time

Question 20

What drug can be given to the patient to dilate the coronary vessels? Why would this help the image/scan?

Answer 20

nitroglycerine; dilating the vessels improves the spacial resolution

Question 21

At what point of the ECG is the heart moving the least?

Answer 21

about 55-75% of the R-R interval; about midpoint of diastole

Question 22

When reconstructing a CT Calcium Study, what planes of the heart should the sagittal and coronal be based off?

Answer 22

off of the long and short axes of the heart

Question 23

Which CT of the chest is considered a “fly-through”? What else is it called?

Answer 23

Bronchography or “virtual bronchoscopy.” Used to visualize the bronchial tree; also, 3D recons are utilized

Question 24

What is the only absolute contraindication for a CTA Coronary?

Answer 24

contraindication for IV contrast

Question 25

A pulmonary nodule is defined as a high density focal spot on the lung measuring at up to ___ cm in diameter

Answer 25

3 cm

Question 26

A _____ _____ on a lung is defined as a high density focal spot measuring more than 3 cm in diameter

Answer 26

focal mass

Question 27

Define ejection fraction.

Answer 27

the quantity of blood pumped out of a ventricle every heartbeat