CT ARRT Exam Questions & Answers 2026 (21–30)

Question 1

The tegmen tympani is the thin bone that separates the middle ear from which adjacent structure?

TheoryPractice · Accepted Answer

Middle cranial fossa. The tegmen tympani is the thin plate of bone forming the roof of the middle ear cavity; it separates the tympanic cavity from the dura of the middle cranial fossa.

Question 2

Which neck space contains the carotid artery, internal jugular vein, and vagus nerve?

TheoryPractice · Accepted Answer

Carotid space. The carotid space (carotid sheath) runs the length of the neck and contains the common/internal carotid artery, internal jugular vein, and vagus nerve (CN X).

Question 3

A lesion that displaces the parapharyngeal fat anteriorly and medially most likely arises from which space?

TheoryPractice · Accepted Answer

Parotid space. Parotid space masses displace the parapharyngeal fat anteromedially, whereas masticator space masses displace it posteromedially; this displacement pattern is key to space-of-origin localization.

Question 4

The normal thyroid gland on non-contrast CT appears as which density relative to adjacent strap muscles?

TheoryPractice · Accepted Answer

Hyperdense (higher HU). The thyroid gland normally appears hyperdense on non-contrast CT (~80-100 HU) due to its intrinsic iodine content, making it distinctly brighter than adjacent neck muscles.

Question 5

On axial CT at the level of the true vocal cords, which cartilage forms the anterior V-shaped midline structure?

TheoryPractice · Accepted Answer

Thyroid cartilage. The thyroid cartilage forms the characteristic anterolateral V-shaped shield at the level of the glottis; its two laminae fuse anteriorly at the laryngeal prominence.

Question 6

The paraglottic space is clinically important because tumor spread through it allows subglottic extension. It is bounded laterally by which structure?

TheoryPractice · Accepted Answer

Thyroid cartilage. The paraglottic space is bounded laterally by the thyroid cartilage and medially by the laryngeal ventricle mucosa; tumor traversing it can reach the subglottis and cartilage, affecting surgical planning.

Question 7

The anterior mediastinum is located anterior to which structure on cross-sectional imaging?

TheoryPractice · Accepted Answer

Pericardium and great vessels. By convention the anterior mediastinum lies anterior to the pericardium and anterior surface of the great vessels; it contains the thymus, lymph nodes, and fat.

Question 8

On axial chest CT, which mediastinal structure lies immediately posterior to the left main bronchus?

TheoryPractice · Accepted Answer

Descending thoracic aorta. The descending thoracic aorta curves to the left after the aortic arch and lies posterior and slightly lateral to the left main bronchus at the carina level.

Question 9

On cardiac CT the right coronary artery (RCA) originates from which coronary sinus?

TheoryPractice · Accepted Answer

Right coronary sinus. The right coronary artery originates from the right (anterior) coronary sinus of Valsalva, while the left main coronary artery originates from the left coronary sinus.

Question 10

Which fissure separates the right upper lobe from the right middle and lower lobes on CT?

TheoryPractice · Accepted Answer

Major (oblique) fissure. The major (oblique) fissure separates the upper and middle lobes from the lower lobe on the right; the minor (horizontal) fissure separates only the right upper from the right middle lobe.

CT ARRT Exam Questions & Answers 2026 (21–30)

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