CT Procedures - head/neck/chest, Final Anatomy, CT ANATOMY ARRT REGISTRY, CT imaging Procedures Registry review, Final -- Imaging Procedures, CT Head and Neck Procedures, Head and Neck Imaging Procedures, CT REGISTRY REVIEW || RATED 100% CORRECT ANSWERS!!
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What kVp would you use for Cranial Fossa correct answers 140
What kVp would you use for Vertex of head correct answers 120
Example of brain window setting correct answers Soft. 100ww/30wl
Narrow width to demonstrate brain tissue w/small difference in attenuations
Example of bone window se...
CT Procedures - head/neck/chest, Final Anatomy, CT
ANATOMY ARRT REGISTRY, CT imaging Procedures
Registry review, Final -- Imaging Procedures, CT Head
and Neck Procedures, Head and Neck Imaging
Procedures, CT REGISTRY REVIEW || RATED 100%
CORRECT ANSWERS!!!
What kVp would you use for Cranial Fossa correct answers 140
What kVp would you use for Vertex of head correct answers 120
Example of brain window setting correct answers Soft. 100ww/30wl
Narrow width to demonstrate brain tissue w/small difference in attenuations
Example of bone window setting correct answers Sharp. 2500/400 average, 4000/400 petrous
bone
Wide
Example of blood window setting correct answers Soft. 200ww/60wl
Covers clotted blood as well as circulating
Head position for head scans correct answers GML
Head position for sinus and facial bones scans correct answers IOML
Head position for neck scans correct answers IOML
Which direction do you scan for neck and head correct answers Caudal - cranial
Which direction do you scan for chest correct answers Cranial - caudal
*exception is when the patient is unable to hold their breath. Greatest motion caused by
diaphragm. Start caudally.
T/F all C- head scans are axial correct answers True
Typical slice thickness/interval for C- head correct answers 3mm/1.5mm - 5mm/2.5mm
What does tPa stand for? correct answers Tissue plasminogen activator
When is the administration of tPa contraindicated? correct answers In cases of hemorrhage
How long does it take for an intracerebral hemorrhage to become hypodense to surrounding
brain tissue? correct answers Approx. 6 months
,T/F routine scanning of the neck is performed in axial mode. correct answers False. The neck
is done helically.
Would you use IV contrast in routine scans of the neck? correct answers Yes, unless
contraindicated.
What is a split-bolus injection technique and when would you use it? correct answers The
total contrast dose is split in half. The first dose is delivered and a delay of 2 min is observed.
This allows time for slow-enhancing structures to become opacified.
Then the second bolus is given and scan begins soon after the injection is complete to re-
opacify the vasculature.
Used for routine neck and for maxillofacial studies.
What is the common protocol for imaging the vessels of the head and neck? correct answers
CTA
3 goals of CTA correct answers 1. Accurately measure stenosis of the carotid and vertebral
arteries and their branches
2. Evaluate the circle of willis for completeness
3. Detect other vascular lesions such as occlusions or dissections.
What is different in CTV in contrast with CTA correct answers Images are acquired during
the venous phase of enhancement. ROI on the left atrium as opposed to the ascending aorta.
What is the timing bolus method correct answers Used in CTA. A single, low-dose slice
repeated every 1 to 2 seconds after the injection of a test bolus. An ROI is placed and time to
peak opacification is measured. Then a saline chaser. Then the full injection and scan at the
pre-measured time.
What is ischemic stroke? correct answers Deficiency of oxygen due to thrombosis or embolis
What is hemorrhagic stroke? correct answers Bleeding in the brain caused by a tear in the
artery wall.
What are the common sites of cerebrovascular atherosclerosis? correct answers Proximal
common carotid artery, the origin of the internal carotid artery, the carotid siphon, and the
proximal middle cerebral and vertebral arteries.
What is a subarachnoid hemorrhage? correct answers Bleeding into the subarachnoid spaces
and the CSF spaces. These are usually caused by the rupture of an aneurysm.
What is an Intracerebral hemorrhage? correct answers A type of stroke that occurs within the
brain parenchyma itself, and a hematoma often results. Most common type of hemorrhagic
stroke, most often the result of hypertension.
What is an AVM? correct answers Ateriorvenous Malformation. Composed of tangles of
arteries and arterialized veins. Caused by scar tissue that resulted from previous small
hemorrhages. AVMs cause blood to be shunted from arterial system to venous, allowing
oxygenated blood to enter the veins.
,To be effective, when should tPa be administered? correct answers Within 3 hours of the
stroke onset.
Why do a CT Brain Perfusion scan? correct answers To measure cerebral blood flow. You
can calculate regional blood flow, regional blood volume and the mean transit time. Perfusion
studies are obtained by monitoring the passage of iodinated contrast through the cerebral
vasculature. Good to distinguish infarcted tissue. The scan involves repeatedly scanning the
same region at the same table position. Most frequently ordered in the evaluation of acute
stroke or tumor grading.
Contrast amount and rate for C+ head correct answers 100 mL at 1.0mL/s. scan delay of 5
minutes
Contrast amount and rate for brain perfusion correct answers 50 mL at 4.0 mL/s; 20 mL
saline flush. Scan delay of 5 s.
DFOV for head scans correct answers 25 cm
Contrast amount and rate CTA CoW correct answers 80 mL at 4.0 mL/s; 40 mL saline flush.
Scan delay from timing bolus.
Why is a good inspiration important in chest CT? correct answers Maximum contrast
Why would you use IV contrast in thoracic imaging? correct answers To differentiate
vascular from non-vascular structures.
Why would you use oral contrast in thoracic imaging? correct answers To improve
visualization of the demarcation of the esophagus and gastroesophageal junction.
T/F CT of the airways is routinely performed at both inspiration and expiration correct
answers True
General protocol for airway imaging correct answers Thin sections (1.25mm or less)
Fast acquisition (one breath hold)
Optimal spatial resolution
Overlapping z-axis slices by 50%
No IV or oral contrast for routine
Why use high-resolution CT (HRCT)? correct answers To evaluate the lung parenchyma in
patients with known or suspected diffuse lung diseases such as fibrosis and emphysema.
What is different in HRCT than C- Chest? correct answers Use an edge-enhancing algorithm
and a DFOV that just includes the lungs. There are often more than one series of scans.
Expiratory Supine - to look for areas of lung that do not empty
Inspiratory Supine - only series done helically
Inspiratory Prone - atelectasis can mimic or hide lung disease.
Why thoracic CTA correct answers Image the heart and thoracic vessels. Most common
indication is pulmonary embolism.
, Route of travel of a thrombus from leg to pulmonary artery correct answers femoral artery -
common iliac - IVC - right atrium - tricuspid - right ventricle - pulmonary valve - pulmonary
trunk - pulmonary artery
When looking for a DVT, what is the protocol? correct answers Complete the CTA. Then do
a CTV to assess for thromobosis in the pelvis or lower extremeties.
delayed venous phase (180 s delay)
SFOV = iliac crest through the knees
What is a low-density filling defect projecting into the vessel lumen, outline by contrast
material correct answers The most reliable sign of an acute embolus
What is a saline flush? correct answers Recommended for pulmonary studies. An amount of
saline is injected after the initial contrast injection. This will eliminate beam-hardening
artifacts from the dense contrast media within the SVC that may obscure small emboli in
adjacent vessels, particularly the on the right side.
How to decrease quantum mottle in patients who are physically larger than average? correct
answers Slightly wider slice thickness (2.0 - 2.5mm)
Name the major coronary vessels correct answers LM (left main) coronary artery
LAD (left anterior descending)
LCX (circumflex)
RCA (right coronary artery
If a patient's heart rate is over 65 bpm, what should be administered correct answers Beta
blockers, prior to scanning.
Metoprolol tartrate is most commonly used.
why administer nitroglycerin correct answers To dilate the vessels
What is ECG gating? correct answers Used to minimize cardiac motion artifact. Scan only
during the point of the cardiac cycle with the least motion, most often this is during end-
diastole.
Two types of ECG gating correct answers Propective ECG triggering (or gating) = uses a
signal to trigger image acquisition. Scan acquisition is synchronized with the patient's heart
rate. Less dose than retrospective.
Retrospective ECG gating = helical data is acquired throughout the cardiac cycle. Images are
then reconstructed in specific portions of the cardiac cycle.
Typical amounts of contrast and rates for cardiac CTA correct answers 300 - 400 mg/mL
injected at a rate of between 3 and 6 mL/s. Total amounts used vary from 70 - 150 mL.
What is the goal of CT for coronary calcium screening correct answers To determine the
location and extent of calcified plaque in the coronary arteries. The amount of calcification is
expressed as a calcium score.
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