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Flashcards in Ch 3 Deck (31):

What disease is not easily diagnosed in a CT Brain scan? What may it appear as?

Alzheimer's disease is not easily diagnosed w/CT brain. May show enlargement of temporal horns.


What is the injection rate and delay in a CTA Brain for the Circle of Willis?

3-4mL/s, 12-20s delay after injection


What does CT Perfusion evaluate? What is the primary indication?

Evaluates cerebral perfusion w/iodine through vascular structures in brain; acute stroke = primary indication


Mean transit time

Average time (in seconds) for blood to pass through area of brain tissue (distance travelled between arterial inflow and venous outflow)


Where is cerebrospinal fluid secreted from?

Choroid plexuses in each of the four ventricles


Central volume principle formula

Cerebral blood flow (CBF) = cerebral blood volume (CBV) / mean transit time (MTT)


What does reduced CBF indicate?

Ischemia due to stroke or other brain abnormalities


What's the best way to reduce contrast-induced nephrotoxicity?

Adequate hydration


Best scout plane for neck



What breathing instructions are used for an HRCT chest?

Full expiration


What does an HRCT chest demonstrate?

Air trapping from suspected small airway diseases (COPD and emphysema)


What is required in CTA PE acquisition?

Peak enhancement of pulmonary arteries, thin sections (0.5-1.25), cauducephalad acquisition w/saline flush after contrast, 80-150mL low- or iso-osmolar contrast


Why do CTVs of lower extremities follow CTAs for PE?

For deep vein thrombosis (blood clots within distal blood vessels), common in popliteal and femoral veins


MDCT cardiac exams for coronary artery calcification (CAC) quantification:

Areas of calcium are identified as greater thab 1mm2 in area with 130+ HU


Branches of RT coronary artery

RT posterior descending artery


Branches of LT coronary artery

LT anterior descending and LT circumflex artery


Blooming definition

Potential overestimation of vessel calcification due to partial volume effect (exaggeration of calcification due to partial volume effect)


In cardiac MDCT studies, blooming can be mitigated with:

Increase in spatial resolution and appropriate window setting (1500HU) to reduce appearance of artifact


Glomerulus definition and entrance/exit of blood and waste

Nephron responsible for filtering unwanted substances from blood plasma; Blood enters through afferent arteriole, exits efferent arteriole; Waste fluid exits through proximal tubule


Azotemia (uremia) definition and symptom of:

Excessive nitrogen in blood; symptom of renal insufficiency and may occur during renal failure


Should dx for renal cysts be done with or without contrast? What should be the attenuation valur of the cyst?

Renal cyst diagnosis done w/contrast. Attenuation values of cyst should be 0


Define glioma

Group of glial tumors in brain (astocytomas, glioblasomas); glial cells are connective nerve cells


What is another name for the pituitary gland? What is it responsible for?

Hypophysis cerebri; responsible for production of hormones (somatotrophin and prolactin)


What are stereotactic unites used for?

Specifically for CT-guided biopsies; commonly for intracranial lesions


What is another name for acoustic neroma and where does it arise from?

Schwannoma; from Schwann cells in 8th cranial nerve (vestibular nerve) seen in IAC exams


What is hydrocephalus?

Abnormal accumulation of cerebrospinal fluid (CSF) in cerebral ventricular system; congenital disorder but can be caused by cranial lesions, hemorrhage, etc


How are coronal paranasal sinuses scanned?

Perpendicular to hard palate


Where is the thymus found? What happens before and after puberty?

Anterosuperior mediastinum; most visible before puberty, after puberty it becomes infiltrated with fat and difficult to image


What are the branches (from RT to LT) of the superior portion of the aortic arch?

Brachiocephalic artery, common carotid artery and the subclavian artery


What factors can be found in the periphery of an image?

Matrix size, algorithm type and section thickness


How much contrast and at what rate would opacify the mediastinum and vascular structures of the chest?

50 - 150mL @ 2.5 - 4.0mL/s