Techniques In Thoracic Imaging

Question 1

What are the disadvantages of portable cxr?

Answer 1

Scattered radiation, inability to capture all relevant information, lack of control over overall optical density if slight under/overexposed

Question 2

What are the acute and non acute indications for CT chest?

Answer 2

Acute - chest trauma, evaluate aortic syndromes, Pulmonary embolus, post thoracic surgery complications
Non acute - nodule assessment, congenital anomalies of great vessels, ILD, bronchiectasis/small airway disease, pulmonary mets

Question 3

What 7 factors can affect radiation dosages in CT?

Answer 3

Gantry geometry, tune current, tube voltage, acquisition modes, collimation, pitch and gantry rotation time.

Question 4

What seven factors affect IV contrast enhancement in CT?

Answer 4

Body weight, cardiac output, concentration/volume of contrast, rate/duration of injection, delay of injection to scan time, duration of scan, bolus tracking.

Question 5

Why is MRI not as good as CT for chest scans?

Answer 5

Poor spatial resolution, low proton density of lungs, artifacts at air-soft tissue interfaces and motion artifacts

Question 6

What are the main indications for Chest MRI?

Answer 6

Evaluate heart and vessels, characterized mediastinal lesions, evaluate superior sulcus tumours, PE if contrast/radiation CI