CT Theory 2 Flashcards
(160 cards)
1
Q
Planes of the body
A
- sagittal: left/right
- coronal: anterior/posterior
- transverse (axial): superior/inferior
2
Q
CT procedure start to finish
A
- Patient and/or rex arrives. Asses clinical info and protocol assigned
- Patient is prepared fro appropriate protocol: lab work, previous exams/artifacts, communication and consent, prepare IV
- Position patient
- Acquire scout images
- Use scout images to set scan parameters
- Perform scan
- Dismiss patient
- Post-processing and storage of images
3
Q
What lab tests are performed?
A
- BUN
- GFR
- Creatinine
4
Q
What medical history is acquired?
A
- allergies?
- surgeries?
- thyroid conditions
- diabetes
- hypertension/heart condition
- pregnancy and breast feeding
- renal function
5
Q
Explanation of procedure?
A
- speak clearly
- ask questions to ensure patient understands
- be a good listener, nod, eye contact
- use language patient understands
- answer questions, seek clarification
- be aware of fears and claustrophobia
- explain as you go
6
Q
NECT vs. CECT
A
NECT: non enhanced
CECT: contrast enhanced
7
Q
Phases of contrast injection?
A
- Arterial (bolus): early 15-25s, late 35sec
- Venous (non-equilibrium):65-80sec
- Delayed Venous (equilibrium): excretory = 3-15min
8
Q
Ways of determining when to trigger a scan post-injection?
A
- Smart Prep:Localizer slice taken, set parameters, set ROI, Series of images taken (usually 2secs apart) to track bolus/CT numbers, Scan is triggered when HU threshold is reached
- Timing Bolus: measures patient cardiac output
9
Q
What are retorspective reconstructions?
A
Change DFOV and/or target to produce image series form within raw data acquired
10
Q
Another name for surface rendering?
A
Shaded surface display
11
Q
Muscles of the rotator cuff?
A
- Supraspinatus: lies in the fossa
- Infraspinatus: large, triangular
- Teres minor: lies just below infraspinatus
- Subscapularis: anterior of scapula
12
Q
When is a CT procedure ordered?
A
- Bone and soft tissue tumors
- To add info to radiographs
- Complex fractures
- Pre-arthroplasty planning
13
Q
Advantages of CT over plain radiographs?
A
- Spatial relationships
- Ability for comparison of joints
- Bone and soft tissue can both be demonstrated with one scan
- Excellent contrast resolution
- MPR and 3D imaging features
14
Q
Contraindications for CT procedures?
A
- Extensive hardware
- Pregnancy
15
Q
General rules of positioning?
A
- Lower extremities: supine, feet first
- Upper extremities: supine, head first
- Ensure symmetry: no rotation
- Axial plane of anatomy perp. to scanner
- Use pillows and sponges to prevent patient motion
16
Q
Shoulder Exam: positioning, anatomy included, FOVs
A
- supine, affected arm at side, unaffected arm raised, head first
- non-contrast
- include above AC joint to scapular tip
- Scout: AP and Lateral
- SFOV: large (body)
- DFOV: 25cm
- Slice thickness: 0.5-1mm
- Slice increment: 0.5-1mm
17
Q
Shoulder exam: window settings, algorithm, reconstructions
A
-Algorithm: bone
-WW: 2000
-WL: 500
-kVp: 140, mA: 300
-Recons:
Standard soft tissue algorithm
MPR: coronal, sagittal, oblique
Surface rendering if indicated
18
Q
Elbow: positioning, anatomy included, FOVs, etc.
A
- prone, affected arm extended over head, or supine with arm by side
- non-contrast
- include above elbow joint to below radial tuberosity
- Scout: AP and Lateral
- SFOV: large (body)
- DFOV: 15cm
- Slice thickness/increment: 0.5-1mm
19
Q
Elbow: algorithm, window settings, reconstructions
A
-Algorithm: bone
-WW: 2000
-WL: 500
-kVP: 140 mA: 300
-Reconstructions:
Standard soft tissue algorithm
MPR: coronal, sagittal, oblique
Surface rendering in indicated
20
Q
Wist: positioning, anatomy included, FOVs, etc.
A
- prone, affected arm extended over head or supine, arm by side
- non contrast
- include proximal wrist joint to proximal metacarpals
- Scout: AP and Lateral
- SFOV: large (body)
- DFOV: 10cm
- Slice thickness/increment: 0.5-1mm
21
Q
Wrist: algorithm, window settings, kVp, mA, recons
A
-Algorithm: bone
-WW: 2000
-WL: 500
-kVp: 140 mA: 300
-Recons
Standard soft tissue algorithm
MPR: coronal, sagittal, oblique
Surface rendering if indicated
22
Q
Hip: positioning, anatomy included, FOVs, etc.
A
- supine, legs flat, DO NOT elevate knees
- non contrast
- include above SI joints to about 4cm below less trochanters
- Scout: AP and Lateral
- SFOV: Large (body)
- DFOV: 30cm (symph to skin)
- Slice thickness/increment: 0.5-1mm
23
Q
Hip: algorithm, window settings, kVp, mA, recons
A
-Algorithm: bone
-WW: 2000
-WL: 500
-kVp: 140 mA: 400
-Recons:
Standard soft tissue algorithm
MPR: coronal, sagittal
Surface rendering if indicated, pre-op planning, most frequently
24
Q
Knee/Tibial plateau: positioning, anatomy included, FOVs, Etc.
A
- supine, legs flat on table, feet taped, or unaffected knee up out of way
- non contrast
- include above patella to below fibular head
- Scout: AP and Lateral
- SFOV: large (body)
- DFOV: 20cm
- slice thickness/increment: 0.5-1mm
25
Knee: Algorithm, window settings, kVp, mA, recons
-Algorithm: bone plus
-WW: 2000
-WL: 500
-kVp: 140 mA: 300
-Recons
Standard soft tissue algorithm
MPR: coronal, sagittal
Surface rendering if indicated, pre-op planning most frequent
26
Ankle: positioning, anatomy included, FOVs, etc.
- supine, legs flat on table, dorsiflex affected foot, move unaffected out of area of interest
- non contrast
- include above ankle joint through calcaneus
- Scout: AP and Lateral
- SFOV: large (body)
- DFOV: 16cm
- Slice thickness/increment: 0.5-1mm
27
Ankle: algorithm, window settings, kVp, mA, Recons
-Algorithm: bone plus
-WW: 2000
-WL: 500
-kVp: 140 mA: 200
-Recons
Standard soft tissue algorithm
MPR: coronal, sagittal
Surface rendering if indicated
28
8 cranial bones?
- Frontal
- Occipital
- Temporal x2
- Parietal x2
- Sphenoid
- Ethmoid
29
Bones in the anterior cranial fossa?
- Frontal
- Ethmoid
- Lesser wings of sphenoid
30
Bones in the middle cranial fossa?
- Sphenoid
- End of carotid canal
- Temporal bones
31
Structures in the posterior cranial fossa?
- Jugular foramen
- Occipital bone
- Foramen magnum
32
What cranial bones does the sphenoid articulate with?
All of them
33
What is the tubercullum sellae?
The anterior wall of the sella turcica (anterior to the dorsum sellae)
34
What are the hypoglossal canals? How do they sit in comparison to the foramen magnum?
Anterolateral to foramen magnum
| -on occipital condyles
35
14 facial bones?
- nasal bones x2
- lacrimal bones x2
- zygoma x2
- maxilla x2
- mandible
- palatine x2
- vomer
- nasal conchae
36
Meninges of brain and their characteristics?
Dura Mater: outermost, strongest, continuous with periosteum
Arachnoid Mater: thin, delicate, middle layer, transparent
Pia Mater: inner, highly vascular, adheres to brain's contours
37
What space contains CSF?
Subarachnoid space: between the pia and arachnoid mater
38
What does the falx cerebri separate?
The cerebral hemispheres
39
What does the tentorium cerebella separate?
Separates the cerebrum and cerebellum
40
What does the flax cerebelli separate?
The cerebellar hemispheres
41
4 ventricles?
- Right and Left Lateral (frontal/anterior horn, occipital/posterior horns, temporal/inferior horns)
- Third Ventricle: thin, slit-like, midline just inferior to lateral ventricles
- Fourth Ventricle: diamond shaped, anterior to the cerebellum and posterior to the pons
42
What parts of the brain does the lateral (sylvian) fissure separate?
The frontal and parietal
43
Where does the corpus collosum sit? What does it form?
Sits above the ventricles, forms the roof of the lateral ventricles
44
What are gyri? What are sulci?
Gyri: folds
Sulci: grooves
45
What is the difference between grey and white brain matter?
Grey: 35-45HU, neuron cell bodies
White: 20-30HU, myelinated sheath on nerves
46
What is the largest and most dense collection of white matter?
Corpus callosum
47
4 segments of the corpus callosum?
1. Rostrum: most anterior
2. Genu
3. Body
4. Splenium: most posterior
48
4 cerebral lobes?
1. Frontal: most anterior
2. Parietal: middle, posterior to central sulcus
3. Occipital: most posterior
4. Temporal: anterior to occipital, separates from the parietal lobes by the lateral fissure
49
Major components of the diencephalon?
- Thalamus: makes up portion of wall of 3rd ventricle, large, oval grey mass
- Hypothalamus: below thalamus, forms floor of 3rd ventricle
- Pituitary gland: connected to the thalamus by the infundibulum
- Epithalamus: most posterior
50
Where does the pineal gland sit?
- on the roof of the midbrain
- just posterior to the 3rd ventricle
- inferior to the splenium of the corpus callosum
51
Major segments of the brainstem?
1. Midbrain: most superior, at junction of middle and posterior cranial fossa
2. Pons: middle, large, oval shaped bulge posterior to clivus and anterior to cerebellum
3. Medulla Oblongata: inferior from pons through foramen magnum
52
Important structures of the cerebellum?
- Lateral hemispheres: folds of grey matter
- Vermis: connects the lateral hemispheres
- Cerebellar tonsils: 2 rounded prominences on the inferior surface
- Cerebellar peduncles: nerve fiber tracts connecting to the midbrain
53
What 2 main pairs of arteries supply blood to the brain?
- Internal carotid arteries: anterior circulation
| - Vertebral arteries: posterior circulation
54
Where do the internal carotid arteries enter the brain? What do they branch into?
Through the carotid canal of the temporal bone
- anterior cerebral artery
- middle cerebral artery (larger)
55
How do the vertebral arteries enter the brain? What do they unite to form?
Through the foramen magnum
| -unite to form the basilar artery
56
Major dural sinuses?
- Superior sagittal sinus
- Inferior sagittal sinus
- Straight sinus
57
In what meninge are the dural sinuses?
The dura mater
58
Where do the dural sinuses drain into?
The internal jugular vein
59
Positioning for a head CT
- head holder or molded sponge
- patient supine, head first into gantry
- normal respiration
- eyes open or closed (can blink)
- SOML or OML
60
Why is it preferred to line up the SOML instead of the OML when CT imaging the head?
Reduced dose to the eye
61
Advantages of conventional head CT?
- allow gantry tilt
- highest image quality
- reduced radiation dose (minimal overlap)
62
Disadvantages of Conventional head CT?
- longer exam time
- limited ability to reconstruct data
- possibility of missed anatomy, misregistration
63
Advantaged of Helical head CT?
- shorter exam time (contrast enhanced studies)
- improved spatial resolution
- ability to reconstruct, use 3D tools
- allows slice increment to be changed retrospectively
64
Disadvantages of helical head CT?
- higher radiation dose
| - does not allow gantry tilt
65
How do we manage beam hardening artifact in the posterior fossa of the head?
- increase kVp
| - decrease slice thickness
66
What setting do we acquire CT brain scans in? Why?
Standard/soft tissue setting
-WW 160
-WL 40
Because it targets grey and white matter
67
Do we use a wide or narrow window width to acquire CT brain scans?
Narrow due to small difference in the tissue attenuation
| -allows best contrast resolution
68
CT brain reconstruction algorithm, WW and WL. Is this a wide or narrow WW?
Bone
-WW 2500
-WL 400
Wide window width due to large difference in the tissue attenuation
69
Types of intracranial hemorrhage?
- Epidural hematoma: lens-shaped, arterial bleed, mass effect, traumatic injury
- Subdural hematoma: venous bleed, crescent shaped
- Subarachnoid hemorrhage: bleeding into ventricular system, increased density with basilar cisterns, fissures, sulci, etc.
- Intracerebral hemorrhage: traumatic injury, damage to vessels or an aneurysm rupture, well circumscribed, high density region
70
Indication for a NECT Head?
- ICH
- Early infarction
- Dementia
- Hydrocephalus
- Trauma
71
Indications for both NECT and CECT head?
- mass or lesion
- arteriovenous malformation
- metastasis
- aneurysm
- headache
- seizure
72
What is CT angiography?
- CT scan with arterial contrast enhancement
- evaluate vascular disease
- gold standard for stroke imaging
73
Advantages of CT angiography over catheter angiography?
- faster
- widely available
- non-invasive
- lower risk of complication
74
Contraindication for a head CT?
- pregnancy (weight risk vs. benefit)
| - contraindication for contrast media
75
NECT head: scouts, anatomy included, positioning, FOVs, algorithm, window settings
```
Scouts: AP and lateral
Anatomy included: vertex to skull base
-SOML or OML
-DFOV: 23cm
-SFOV: head
Algorithm: standard
WW: 140 WL 40
```
76
NECT head: recon algorithm and window settings, technique, post processing
Recon algorithm: bone
WW: 4000 WL: 40
kVp: 120-140 mA: 150
Post processing: coronal and sagittal reformats
77
CECT: scouts, anatomy included, positioning, FOVs, algorithm, window settings
```
Scout: AP and Lateral
Anatomy included: vertex to base of skull
-SOML or OML
-DFOV: 23cm
-SFOV: head
Algorithm: standard
WW: 140 WL 40
```
78
CECT: recon algorithm and window settings, technique, post processing
Recon algorithm: bone
WW: 4000 WL: 400
kVp: 120-140 mA: 150
Post processing: coronal and sagittal reformats
79
CECT head contrast volume and scan delay
IV contrast: 100ml at 1.0ml/sec
Scan delay: 5 mins
Oral contrast: none
80
Common indications for CT sinuses?
- chronic sinusitis
- inflammatory sinus disease
- pro-operative
81
Contraindications for CT sinuses?
- pregnancy
| - extensive hardware
82
CT sinuses: scout, anatomy included, positioning, FOVs, algorithm, window settings
```
Scout: Lateral
Anatomy included: entire frontal sinus to sella turcica, and entire frontal sinus to entire maxillary sinus
-OML
-DFOV: 16cm
-SFOV: head
Algorithm: standard
WW: 350 WL: 50
```
83
CT sinuses: recon algorithm, window settings, technique, post processing
Recon algorithm: bone
WW: 4000 WL: 400
kVP: 120 mA: 150
Post processing: coronal and sagittal reformats
84
Are CT sinuses NECT, CECT, or both?
NECT
85
Common indications for CT facial bones?
- facial fracture
- soft tissue injury
- foreign body
86
Contraindications for CT facial bones?
- pregnancy
| - extensive hardware
87
CT facial bones: Scout, anatomy included, positioning, FOVs, algorithm, window settings
```
Scout: AP and Lateral
Anatomy included: entire frontal sinus to mandible and nose to sella turcica
-IOML
-DFOV: 18cm
-SFOV: head
Algorithm: standard
WW: 350 WL: 50
```
88
CT facial bones: reconstruction algorithm, window settings, technique, post processing
Recon algorithm: bone
WW: 4000 WL: 400
kVp: 120 mA: 150
Post processing: coronal and sagittal reformats, helical scans allow 3D surface rendering if indicated
89
Common indications for CT NECT orbits?
- Foreign body
| - trauma
90
Common indications for CECT orbits?
- intraorbital mass
- thyroid opthalmopathy
- inflammation
- infection
- trauma-vascular injury
91
Contraindications for CT orbits?
-Pregnancy
92
NECT and CECT orbits: scout, anatomy included, positioning, FOVs, algorithm, window settings
```
Scout: AP and Lateral
Anatomy included: orbital roofs to orbital floors
-IOML
-DFOV: 16cm
-SFOV: head
Algorithm: SOFT
WW: 350 WL: 50
```
93
NECT and CECT orbits: reconstruction algorithm, technique, post processing
Recon algorithm: Bone
WW: 4000 WL: 400
kVp: 120 mA: 200
Post-processing: coronal and sagittal reformats, helical scans allow 3D rendering if indicated
94
CECT orbits contrast protocol?
```
IV contrast: 100 ml at 1.0ml/sec
Scan delay: Split bolus
-50ml @ 1ml/sec
-2 minute delay
-50ml @ 1ml/sec
-scan immediately following second bolus
Oral contrast: none
```
95
Common indications for CTA circle of willis?
- locate known aneurysm
- arteriovenous malformation
- assessment of known intracranial hemorrhage
96
Contraindications for CTA circle of willis?
- pregnancy
| - if NECT has not been performed! NEVER do unless a patient has already had a dry scan
97
CTA Circle of Willis: scout, anatomy included, FOVs, algorithm, window settings, technique, post processing
```
Scout: AP and Lateral
Anatomy included: just above frontal sinuses to just below skull base
-DFOV: 25cm
-SFOV: head
Algorithm: standard
WW: 140 WL: 40
kVP: 120 mA: 500
Post processing: coronal, sagittal, oblique, etc.
```
98
CTA circle of willis contrast protocol?
```
IV contrast: 60ml @ 4ml/sec
Scan delay: smart prep
-ROI on carotid artery
-Scan starts once adequate contrast enhancement of the carotid artery is reached
Oral contrast: none
```
99
The oropharynx is separated from the larynx by what?
Epiglottis
100
Which part of the pharynx has the piriform sinuses?
Laryngopharynx
101
Sphenoid sinuses sit where in relation to the nasopharynx?
More posterior
102
At what vertebral level is the larynx?
C3-C6
103
Where is the thyroid cartilage in relation to the thyroid?
Superior
104
Do the salivary glands appear darker or lighter than muscle?
Darker
105
Where is the esophagus in relation to the trachea?
Posterior
106
Salivary glands
1. Parotid (largest)
2. Submandibular
3. Sublingual (anterior to submandibular)
107
Where do the parotid glands sit?
Extend from the level of the EAM to the gonion
108
Why do the parotid gland appear different from the other salivary glands?
Fatty tissue and lymph nodes within the glands
109
Where do the submandibular glands sit?
Extend from the gonion to the hyoid bone
110
The two lobes of the thyroid are joined anteriorly by the?
Isthmus
111
Where does the right common carotid artery rise from?
The brachiocephalic artery posterior to the SC joint
112
Common carotid arteries bifurcate into the internal and external carotid arteries at what vertebral level?
C3-C4
113
Where is the common carotid artery in relation to the internal jugular vein?
Medial
114
Where do the internal and external carotid arteries enter the skull?
Internal carotid: carotid canal of temporal bone
| External carotid: parotid gland to level of TMJ
115
Vertebral arteries ascend through the transverse foramina of C____ to C___?
C6 to C1 and enter the skull through the foramen magnum
116
What are typically the largest vessels in the neck?
Internal jugular veins
117
Where do the external jugular veins empty into?
The subclavian vein
118
Where do vertebral veins drain into?
The brachiocephalic vein
119
Patient positioning for CT neck
- head holder
- supine, head first into gantry
- suspend respiration
- suspend swallowing
- hard palate parallel to gantry
- reach arms down, depress shoulders
120
Challenges in scanning CT neck?
- Dental work: split the scan superior and inferior to dental work and angle between to avoid streaks
- Large shoulder: depress shoulders as much as possible
121
How are CT images of the neck viewed?
- MPR
- Standard/soft tissue WW: 160 WL: 40
- Soft algorithm: WW: 350 WL: 50
- Bone: WW: 2500 WL: 400
122
Common indications for CECT soft tissue neck?
- neck mass
- vascular abnormality
- lymphadenopathy
- cysts
- abscess
123
Common indications for NECT soft tissue neck?
-salivary stones: contrast will obscure stone
124
Contraindications for Neck CT?
- pregnancy
| - contraindications for contrast media
125
3 categories of strokes?
1. Ischemic
2. Hemorrhagic
3. Hypotensive
126
Risk factors to stroke?
- hypertension
- homocysteine and Vit B deficiency
- high cholesterol
- atrial fibrillation
- heart disease
- diabetes
- migraines
- heredity
- smoking
- obesity
- substance abuse
127
Two main types of ischemic stroke?
- thrombotic: blood clot in artery
| - embolic: traveling particle in the bloodstream that lodges in a smaller artery, cutting off blood flow
128
What is a hypotensive stroke?
- rare
| - blood pressure is too low, can reduce oxygen supply to the brain
129
What is a TIA?
Reversible episode of neurologic dysfunction that could last a few mins to a few hours
- caused by tiny emboli that lodge in an artery, but then move on or dissolve
- an indicator of stroke risk
130
TIA of the carotid arteries symptoms?
- vision loss
- speech
- partial or temp. paralysis
- tingling
- numbness
- unilateral symptoms
131
TIA of the basilar artery symptoms?
- dim, grey, blurry vision
- vision loss in both eyes
- tingling in mouth, cheeks, gums
- headache, posterior often
- dizziness
- nausea, vomiting
- difficulty swallowing
- inability to speak clearly (confusion)
- weakness in arms or legs
132
CTA for stroke imaging is used for?
- show spatial relationship of lesions to the brain tissues
- evaluate integrity of vessels
- accurate measurements of stenosis of a vessel
- evaluate the circle of willis and carotid arteries
- detect vascular lesions such as dissection or occlusions
133
t-PA is effective when administered within ______ hours after the first signs of a stroke?
3
134
CECT soft tissue neck: scouts, anatomy included, FOVs, algorithm, window settings
```
Scouts: AP and Lateral
Anatomy included: mid-orbit to mid-clavicle (t2-t3)
-DFOV: 18cm
-SFOV: large body
Algorithm: standard (or soft)
WW: 350 WL: 50
```
135
CECT soft tissue neck: reconstruction algorithm, technique, post processing
Recon algorithm: bone
WW: 4000 WL: 400
kVP: 120 mA: 150* automatic mA
Post processing: coronal and sagittal reformats, retrospective recons of c spine can be done due to large SFOV
136
CECT soft tissue neck contrast protocol?
125ml at 1.5ml/sec
- split bolus:
- 50ml
- 2 min
- 75 ml
- scan 20-30secs after 2nd injection
- oral contrast: sometimes, rare
137
CTA COW and Carotids "stroke protocol": Scouts, anatomy included. FOVs, algorithm, window settings
```
Scout: AP and Lateral
Anatomy included: aortic arch to just above frontal sinus
-DFOV: 25cm
-SFOV large body
-Algorithm: standard
WW: 250 WL 30
```
138
CTA COW and Carotids: reconstruction algorithm, technique, post porcessing
Recon algorithm: MIP
WW 800 WL 200, thin slices
kVp: 120 mA: 500
Post processing: coronal, sagittal, oblique
139
CTA COW and carotids contrast protocol
80ml at 4ml/sec
Scan delay: bolus tracking/smart prep
-ROI on carotid artery at C4
-oral contrast: none
140
Patient position for CT chest
- supine
- arm elevated
- feet first into gantry
- reduce patient motion
- suspend respiration
- no rotation
141
Challenges in scanning a CT chest
Involuntary motion: respiration and cardiac function
-use shortest scan time possible, scan caudal to cranial (less motion at apices)
Patient Mobility: unable to raise arms above head and hold still
-use immobilization or scan with patients arms at side
142
How are ct chests viewed?
- multiple MPR
- standard soft tissue: WW 350 WL 50
- lung: WW 1500 WL -700
143
3 major protocol categories of CT chest?
- Routine CECT chest
- Hi-res NECT chest
- CTA chest for pulmonary embolism
144
Common indications for routine CECT chest?
- infection
- mass
- empyema
- correlate with radiographs
- known or suspected congenital abnormalities
- trauma
- lung CA
145
2 protocols for NECT chests?
- Lung nodule protocol: inspiration, thin reconstructions, use when correlating nodule seen on radiography
- High resolution protocol: inspiration and expiration, asbestos exposure, inhalation injury, interstitial lung disease, diffuse pulmonary disease, bronchiectasis, airway disease
146
Volumetric HRCT
- helical
- covers entire lung rather than representative slices
- complete assessment of lung
- capable of 3D post-processing (MIP and MinIP)
- primary disadvantage: patient dose
- include more than one series of scans: supine inspiration and expiration, prone inspiration
147
HRCT supine inspiration vs. expiration vs. prone expiration
Inspiration: demonstrated best contrast between air and lung
Expiration: demonstrated air trapping in lung
Prone Inspiration: differentiates disease from the effect of gravity on blood flow and gas volume
148
How to decrease dose n HRCT?
- helical mode for supine inspiration, step and shoot for others
- can decrease tube mA
149
Contraindications for CT chest?
- pregnancy
| - contraindication to contrast media if required
150
CECT chest: scout, anatomy included, FOVs, algorithm
```
Scout: AP and Lateral
Anatomy included: above lung apices to below costophrenic angles
DFOV: set to patient
SFOV: large body
-Standard soft tissue: WW 350 WL 50
```
151
CECT chest: Reconstruction algorithm, techniques, post-processing
Recon algorithm: Lung WW 1500 WL -700
kVP 120 mA 100-150 (use auto mA)
Post processing: usually create thin slices in MPR
-pitch is greater than 1 for a lot of chest scans
152
CECT chest contrast protocol?
80ml at 3ml/sec
Scan delay: 35 secs
-bolus followed by saline flush for all CECT imaging but especially important for chest imaging
-Oral contrast: not used
153
NECT chest: lung nodule: scouts, anatomy included, FOVs, algorithm
```
Scouts: AP and Lateral
Anatomy included: above lung apices to below costophrenic angles
DFOV: set to patient
SFOV large body
-Standard soft tissue: WW 350 WL 50
```
154
NECT chest: lung nodule: Reconstruction algorithm, techniques, post-processing
Recon algorithm: lung WW 1500 WL -700
kVP 120 mA 80-160
Post processing: thin sections through various nodules, often use edge enhancing algorithm to sharped the resolution of nodule itself
155
NECT chest: high resolution: Scouts, anatomy included, FOVs, algorithm
Scouts: AP and Lateral
Anatomy included: above ling apices to below costophrenic angles
DFOV: set to patient/lung field only
SFOV: lung WW 1500 WL -700
156
NECT chest: high resolution: reconstruction algorithm, technique, post processing
Recon algorithm: none
kVP 140 mA 150-375
Post processing: thin slices created in lung windows to show detail of lung parenchyma
**for prone expiration only include from carina to just below costophrenic angles**
157
CTA chest PE: Scouts, anatomy included, FOVs, algorithm
Scouts: AP and Lateral
Anatomy included: below hemidiaphragm to apices (inferior to superior) venous runoff: 2cm below tibial plateau to iliac crests
DFOV: 38cm, 48 (venous runoff)
SFOV: large body
-standard WW 700 WL 180 (optimal for vascular)
158
CTA chest PE: reconstruction algorithm, technique, post processing
Recon algorithm: site protocol dependent
kVP 120 mA 500
Venous runoff: kVp 120 mA 190
Post processing: MIP with thin slices, coronal image series always created of chest
159
CTA chest PE contrast protocol (method 1 with venous runoff)
120ml split bolus
-70ml at 4ml/sec Smart prep ROI over pulmonary artery
-50ml at 3ml/sec 25 secs after first injection
Scan delay: bolus tracking, arterial phase, lower extremity 180 secs after first bolus
160
CTA chest PE contrast protocol (method 2 timing bolus) *more accurate*
- 20ml at 4ml/sec to measure cardiac output, ROI on pulmonary artery
- 60-80ml at 3ml/sec, use scan delay calculated
- average patient = 10-12 seconds post injection
