TheoryCT ARRT
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30 free CT ARRT questions
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Cross-Sectional Anatomy
Which lobe of the brain is located in the most anterior portion of the cranium?
Correct — A. The frontal lobe occupies the anterior cranial fossa and is the most anteriorly positioned cerebral lobe, lying anterior to the central sulcus. -
Cross-Sectional Anatomy
The primary visual cortex is located in which lobe of the cerebrum?
Correct — C. The primary visual cortex (V1) resides in the occipital lobe, specifically along the calcarine sulcus, and processes visual input from the retinas. -
Cross-Sectional Anatomy
The third ventricle communicates with the lateral ventricles through which structure?
Correct — B. The paired foramina of Monro (interventricular foramina) connect each lateral ventricle to the midline third ventricle, allowing CSF to flow between them. -
Cross-Sectional Anatomy
Which structure connects the third ventricle to the fourth ventricle?
Correct — D. The cerebral aqueduct (aqueduct of Sylvius) is a narrow channel through the midbrain that connects the third and fourth ventricles. -
Cross-Sectional Anatomy
On axial CT the lentiform nucleus is separated from the caudate nucleus by which structure?
Correct — A. The internal capsule is the white matter tract that separates the lentiform nucleus (putamen + globus pallidus) from the caudate nucleus and thalamus. -
Cross-Sectional Anatomy
The cerebellum is separated from the occipital lobes by which structure?
Correct — B. The tentorium cerebelli is a dural fold that forms a tent-like partition separating the cerebellum (infratentorial) from the occipital lobes (supratentorial). -
Cross-Sectional Anatomy
From superior to inferior, what is the correct order of brainstem components?
Correct — D. The brainstem consists of the midbrain (most superior), pons (middle), and medulla oblongata (most inferior, continuous with the spinal cord). -
Cross-Sectional Anatomy
The crus cerebri (cerebral peduncles) is a landmark of which brainstem level on axial CT?
Correct — A. The cerebral peduncles (crura cerebri) are large fiber bundles on the anterior midbrain and are the key identifying landmark of the midbrain level on axial CT. -
Cross-Sectional Anatomy
The trigeminal nerve (CN V) exits the posterior cranial fossa via which opening?
Correct — B. CN V exits through the porus trigeminus into Meckel's cave at the petrous apex before its branches exit via foramina rotundum, ovale, and spinosum; the main root traverses the petrous apex dural cave. -
Cross-Sectional Anatomy
Which cranial nerves travel through the internal acoustic meatus (IAM)?
Correct — C. The facial nerve (CN VII) and vestibulocochlear nerve (CN VIII) both travel together through the internal acoustic meatus, making the IAM a critical landmark for these nerves. -
Cross-Sectional Anatomy
The superior sagittal sinus drains into which venous structure at the internal occipital protuberance?
Correct — D. The superior sagittal sinus drains posteriorly to join the confluence of sinuses (torcular Herophili) at the internal occipital protuberance, where multiple dural sinuses meet. -
Cross-Sectional Anatomy
Which artery supplies the medial surface of the frontal and parietal lobes?
Correct — B. The anterior cerebral artery (ACA) curves over the corpus callosum and supplies the medial frontal and parietal lobes, including the supplementary motor area and lower limb cortex. -
Cross-Sectional Anatomy
Which artery is most commonly implicated in posterior communicating artery aneurysm causing CN III palsy?
Correct — D. Aneurysms at the junction of the internal carotid artery and the posterior communicating artery (PCom) are the most common cause of a painful CN III (oculomotor) palsy due to direct nerve compression. -
Cross-Sectional Anatomy
The foramen spinosum transmits which vessel into the middle cranial fossa?
Correct — A. The middle meningeal artery, a branch of the maxillary artery, enters the skull through the foramen spinosum to supply the dura and periosteum of the middle cranial fossa. -
Cross-Sectional Anatomy
The jugular foramen transmits which combination of structures?
Correct — C. The jugular foramen transmits CN IX (glossopharyngeal), CN X (vagus), CN XI (accessory), and the internal jugular vein (continuation of the sigmoid sinus). -
Cross-Sectional Anatomy
Which foramen in the greater wing of the sphenoid transmits the mandibular division of CN V (V3)?
Correct — B. The foramen ovale transmits V3 (mandibular division of the trigeminal nerve) along with the lesser petrosal nerve and accessory meningeal artery. -
Cross-Sectional Anatomy
Which structure forms the posterior boundary of the orbit and allows passage of the optic nerve?
Correct — A. The optic canal, located in the lesser wing of the sphenoid, transmits the optic nerve (CN II) and ophthalmic artery from the middle cranial fossa into the orbit. -
Cross-Sectional Anatomy
Which paranasal sinus is most commonly involved in acute sinusitis due to its dependent position and narrow ostium?
Correct — B. The maxillary sinus has its ostium high on the medial wall (not at the floor), making dependent drainage difficult and predisposing it to fluid accumulation and infection. -
Cross-Sectional Anatomy
The ostiomeatal complex (OMC), the key drainage pathway for the anterior sinuses, is best evaluated on which CT plane?
Correct — C. Coronal CT is the standard plane for evaluating the ostiomeatal complex because it displays the maxillary ostia, ethmoid infundibulum, uncinate process, and middle meatus in a single plane. -
Cross-Sectional Anatomy
On high-resolution axial CT of the temporal bone, the cochlea normally shows approximately how many turns?
Correct — A. The human cochlea makes approximately 2.5 turns from its base to its apex, a consistent anatomic feature used to assess cochlear development on CT. -
Cross-Sectional Anatomy
The tegmen tympani is the thin bone that separates the middle ear from which adjacent structure?
Correct — D. 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. -
Cross-Sectional Anatomy
Which neck space contains the carotid artery, internal jugular vein, and vagus nerve?
Correct — B. 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). -
Cross-Sectional Anatomy
A lesion that displaces the parapharyngeal fat anteriorly and medially most likely arises from which space?
Correct — C. 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. -
Cross-Sectional Anatomy
The normal thyroid gland on non-contrast CT appears as which density relative to adjacent strap muscles?
Correct — A. 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. -
Cross-Sectional Anatomy
On axial CT at the level of the true vocal cords, which cartilage forms the anterior V-shaped midline structure?
Correct — B. 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. -
Cross-Sectional Anatomy
The paraglottic space is clinically important because tumor spread through it allows subglottic extension. It is bounded laterally by which structure?
Correct — D. 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. -
Cross-Sectional Anatomy
The anterior mediastinum is located anterior to which structure on cross-sectional imaging?
Correct — C. 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. -
Cross-Sectional Anatomy
On axial chest CT, which mediastinal structure lies immediately posterior to the left main bronchus?
Correct — A. 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. -
Cross-Sectional Anatomy
On cardiac CT the right coronary artery (RCA) originates from which coronary sinus?
Correct — D. 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. -
Cross-Sectional Anatomy
Which fissure separates the right upper lobe from the right middle and lower lobes on CT?
Correct — C. 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 sample questions
Tap any question below to reveal the answer and a plain-English explanation.
Cross-Sectional Anatomy The minor (horizontal) fissure on the right extends from the major fissure to the lateral chest wall at approximately which rib level on a PA view?
A. 2nd rib anteriorly
B. 3rd rib anteriorly
C. 4th rib anteriorly ✓
D. 5th rib anteriorly
Correct — C. The right minor (horizontal) fissure normally projects at approximately the level of the anterior 4th rib on a PA chest radiograph and appears as a horizontal line on lateral CT reformation.
Contrast What is the primary purpose of iodinated contrast media in CT imaging?
A. To increase the attenuation of vascular and soft-tissue structures ✓
B. To decrease radiation dose to the patient
C. To improve spatial resolution of the image
D. To reduce image noise
Correct — A. Iodinated contrast media contain iodine atoms that attenuate X-rays more strongly than surrounding tissue, increasing the Hounsfield unit values of enhanced structures and improving conspicuity. They do not alter dose, resolution, or noise in the traditional sense.
CT ARRT Which of the following contrast agents is classified as a non-ionic iso-osmolar dimer?
A. Diatrizoate
B. Ioxaglate
C. Iohexol
D. Iodixanol ✓
Correct — D. Iodixanol is a non-ionic dimer with an osmolality of approximately 290 mOsm/kg, matching blood plasma (iso-osmolar). Iohexol is a non-ionic low-osmolality monomer; ioxaglate is an ionic low-osmolality dimer; diatrizoate is an ionic high-osmolality monomer.
Image Production What does the term 'pitch' refer to in helical CT scanning?
A. The angle of the X-ray tube relative to the isocenter
B. The distance the table travels per gantry rotation divided by beam width ✓
C. The number of detector rows activated during a scan
D. The rate at which image reconstruction occurs
Correct — B. Pitch = table distance per rotation ÷ nominal beam width (or detector row width × number of rows). A pitch of 1.0 means the table advances exactly one beam width per rotation, while values >1 indicate gaps and values <1 indicate overlap.
Instrumentation Which component of a CT scanner converts X-ray photons into an electrical signal?
A. Detector ✓
B. X-ray tube
C. Collimator
D. Gantry
Correct — A. Detectors (typically solid-state or gas-filled ionization chambers) absorb X-ray photons and convert them into electrical signals that are then digitized. The X-ray tube produces the beam; the collimator shapes it; the gantry is the rotating housing.
Patient Care Before performing a CT scan, which TWO identifiers should be used to confirm patient identity per Joint Commission standards?
A. Patient name and date of birth ✓
B. Patient name and room number
C. Room number and date of birth
D. Insurance ID and room number
Correct — A. The Joint Commission requires at least two patient identifiers before any procedure; acceptable identifiers include name, date of birth, and medical record number — but NOT room or bed number.
CT Physics What is the primary interaction responsible for producing the continuous X-ray spectrum (Bremsstrahlung)?
A. Characteristic emission from inner-shell electrons
B. Photoelectric absorption of photons in the target
C. Deceleration of electrons in the Coulomb field of the target nucleus ✓
D. Compton scattering of electrons within the anode
Correct — C. Bremsstrahlung ('braking radiation') occurs when a high-speed electron decelerates as it passes near a target nucleus; kinetic energy is converted directly into X-ray photons. Characteristic radiation arises from inner-shell transitions, not the continuous spectrum.
Procedures by Region Which landmark is used to position the gantry for a routine axial head CT?
A. Orbitomeatal line (OML) ✓
B. Infraorbitomeatal line (IOML)
C. Glabellomeatal line
D. Mentomeatal line
Correct — A. The orbitomeatal line (OML), extending from the outer canthus of the eye to the EAM, is the standard baseline for routine axial head CT positioning to maintain reproducibility.
About the CT ARRT test
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Topics in this question bank
Safe and effective care environment
Health promotion and maintenance
Psychosocial and physiological integrity
Pharmacology, infection control and patient safety
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