Unit IV_CT, fluoroscopy and Ultrasound Flashcards
1
Q
Ultrasound (non-diagnostic and diagnostic) has a frequency of ________ hertz?
A
>20,000 Hertz (20 KHz) Higher than threshold of human hearing
2
Q
Diagnostic Ultrasound (done in imaging) utilizes an ultrasound frequency within what range?
A
3-9 megahertz (3-9 MHz)
3
Q
Differentiate between: Ultrasonography Sonography Sonogram
A
basically used interchangeably but… the suffix -ography is the field of study the suffix-gram pertains to the images themselves
4
Q
Most common image form in diagnostic ultrasound
A
grey-scale real time ultrasound
5
Q
What is a transducer?
A
~the hand held device that converts energy (what makes contact with the patient). Step 1-It converts electrical energy to the ultrasounds that are introduced into the patient. Step 2-It listens for returning echoes. Step 3-converts returning ultrasound echoes into electrical energy for the machine to process.
6
Q
Does the ultrasound tranducer transmit sound or listen for returning echoes longer?
A
Listens 9 times longer than it transmits.
7
Q
What determines the image in ultrasound?
A
The reflectivity of the tissue. The sharpest images are the generated by a very strong returning echo (the ball bounces straight back off the wall and not deflected to the side)
8
Q
What is the sound reflectivity of bone? How does it appear on the monitor?
A
Excellent reflectivity White on monitor
9
Q
What is the sound reflectivity of fluids? How does it appear on the monitor?
A
Very poor reflectivity Black on monitor
10
Q
What is the sound reflectivity of muscle/liver? How does it appear on the monitor?
A
Intermediate reflectivity Various degrees of grey
11
Q
What is the sound reflectivity of tissue transition zones? How does it appear on the monitor?
A
Good reflectivity White on monitor
12
Q
How is ultrasound different than x-ray
A
~Reflects energy (sound) rather than penetrate (radiation) ~Lower energy levels ~Non-ionizing
13
Q
The WHO states that ultrasound is harmless. What is the more cautious approach?
A
as currently used, diagnostic ultrasound does not appear to harm biologic tissues.
14
Q
What ultrasound frequency shows better detail, 3 MHz or 5-7 MHz? what is the trade off?
A
5 MHz can only visualize shallower structures Note: the greater the frequency, the shorter the wavelength.
15
Q
Do you want low or high ultrasound frequency to show better detail?
A
Higher frequency (5-7 MHz)
16
Q
Dow you want low or high ultrasound frequency to get the deeper structures.
A
Lower frequency (3 MHz)
17
Q
What is an example of a higher frequency ultrasound transducer?
A
Vaginal probes
18
Q
What is an example of a lower frequency ultrasound transducer?
A
abdominal probe
19
Q
What is coupling gel?
A
a water soluble gel used to eliminate the air interface between the transducer and patient skin.
20
Q
What are the two different tranducer types for pelvic ultrasound examinations?
A
Abdominal Vaginal
21
Q
What gestational age is best visualized with a trans-abdominal approach?
A
> 12 weeks gestation ~morphology & development ~health/viability (Biophysical Profile)
22
Q
When would trans-abdominal ultrasound be preferred over endovaginal ultrasound when evaluating a pregnancy?
A
Best for fetus > 12 weeks Best for placenta > 12 weeks Note: endovaginal probes have a very high frequency and can not penetrate the sound to the depths needed in large gravid uterus.
23
Q
What patient prep is needed for a transabdominal pelvic ultrasound?
A
full bladder
24
Q
Why is a full bladder needed for a transabdominal pelvic ultrasound
A
Creates a window for sound waves by pushing the air filled bowel up and out of the way.
25
What are the advantages of endovaginal ultrasound over transabdominal pelvic ultrasound?
~Higher frequency provides excellent resolution ~excellent visualization of uterus and EARLY gestations (\<12 weeks) ~good resolution of adnexa ~full bladder not required.
26
Vaginal Ultrasound is best for _______ and \_\_\_\_\_\_\_\_.
GYN problems Early pregnancy
27
(trans) Abdominal Ultrasound (for female pelvis) is best for \_\_\_\_\_\_\_\_.
evaluation of pregnancy in 2nd and 3rd trimester.
28
What can be seen in the uterine evaluation with U/S?
Size and position Endometrium Myometrial pathology Masses, fluid and foreign bodies
29
What can be seen in the ovarian evaluation with U/S?
~ovarian sizes and locations ~follicles (fertility treatment, polycystic ovary) ~Detect and analyze ovarian enlargements ~vacularity (r/o torsion)
30
what is seen in the obstetrical evaluation of an early pregnancy?
Pregnancy location Pregnancy viability multiple gestation
31
What is seen in the obstetrical evaluation of a mid term pregnancy?
congenital anomalies confirm multiple gestation gender determination
32
What is seen in the obstetrical evaluation of a late term pregnancy?
~monitor fetal growth ~placenta location ~fetal lie (presentation) ~well being (Biophysical Profile) ~Amniotic fluid volume ~Fetal respiratory movements
33
What is evaluated in a fetal growth assessment?
~Biparietal diameter ~Femur length ~Abdominal circumference ~others
34
What is a biophysical profile? what is assessed?
assessment for fetal well-being ~Respiratory movements ~Amniotic fluid volume ~Placenta morphology ~others
35
What is Doppler ultrasound?
assesses blood flow (organs, fetus, tumors)
36
Normal grey scale ultrasound is 2-dimensional. What two types of ultrasound does Dr. Dodge term as "fancy"
3-dimensional 4-dimensional
37
What are advantages to ultrasound imaging over other diagnostic imaging tests?
Non-invasive Less-cost Real time images Portable No radiation exposure
38
What are disadvantages of ultrasound?
~Can not image through air or bone. ~Sonographer error
39
a complete abdomen ultrasound evaluated what organs?
Liver Gallbladder Spleen Pancreas (sometimes Kidneys, dependent on department protocol)
40
What is the patient prep for abdominal ultrasound?
NPO 8 hours (gallbladder)
41
What is evaluated in a limited abdomen U/S
one of the following structures: Liver Gallbladder Spleen Pancreas Appendix Pylorus
42
What modality is preferred when evaluating the appendix
CT scan is preferred. a bad appendix can be missed on U/S due to the gas in the bowel.
43
What ultrasound examination will show renal artery stenosis with questionable accuracy?
Kidneys
44
what is a common ordering error for ultrasounds noted by the ultrasound lecturer?
R/out. The reason for exam should be specific and never use a "rule out" reason for exam.
45
What is the prep for a abdomen ultrasound (specifically gallbladder)?
NPO 8 hours
46
Why is the NPO prep for the abdomen ultrasound (specifically gallbladder) important.
A constricted (due to eating) gallbladder and a constricted (due to disease) gallbladder look the same.
47
What is the cheapest special modality in imaging (besides routine x-rays)?
ultrasound
48
What is fluorosopy?
live x-rays (continuous "on" time) visualized on a monitor during examination
49
what energy does fluoroscopy use to obtain images?
radiation (exactly like diagnostic x-rays)
50
What is used in an fluoroscopy examination to enhance detail of strutures?
Contrast
51
What types of contrast are used in imaging?
barium iodinated air
52
What types of imaging contrast are NEVER used intravenously.
Barium Sulfate Air
53
What type of contrast can be used both orally and intravenously?
Iodinated
54
What type imaging contrast of can be used intravenously?
Iodinated only
55
What is a Modified Barium Swallow?
~a fluoroscopic examination to assess swallowing mechanisms. ~done with the assistance of a speech pathologist. ~multiple consistency food will be mixed with barium and watched fluoroscopically for aspiration and movement of food bolus past epiglottis down esophagus
56
What is the patient prep for the Modified Barium Swallow examination?
No Prep Note: the stomach is not visualized, therefore food does not get in the way of area of interest
57
Why is it important for a patient to be NPO for a fluoroscopic examination of the GI tract.
Food particles can mimic lesions within the alimentary canal.
58
What are the contraindications for a Modified Barium Swallow?
possibility of aspiration of non-water soluble barium
59
Why is barium contraindicated in GI studies when bowel perforation or obstruction is suspected.
Barium is not sterile Barium is not water soluble Patient could develop peritonitis (perforation) or concrete stool (constipation from absorption of water from barium)
60
What is the difference from a barium swallow and a modified barium swallow?
Barium swallow is an evaluation of the entire esophagus but NOT the swallowing mechanism. Modified Barium Swallow is an evaluation of the swallowing mechanism and not the entire esophagus. done with speech pathologist present.
61
What are the routine contrasts used on a Barium swallow (esophogram)? What can be used as an alternative contrast if bowel perforation is suspected (or compromised patient where aspiration should be considered)?
Barium Sulfate Air Iodinated contrast (i.e. gastroview)
62
What is an alternative oral contrast that can be used when barium is contraindicated?
Iodinated contrast (i.e. gastroview)
63
What are the indications for a barium swallow (esophogram) study?
acid reflux intraluminal lesions strictures obstructions esophageal varicies hiatal hernia foreign bodies
64
What is an Upper GI (UGI)?
Fluoroscopic examination utilizing oral contrast of the stomach and emptying into the very proximal small bowel
65
Is IV contrast used on an Upper GI (UGI) exam?
Nope
66
What are contrasts that can be used for an Upper GI (UGI) exam?
Barium Sulfate Air Iodinated contrast (2nd choice to barium in compromised patient)
67
What is the patient prep for an esophogram?
None Be aware that the Esophogram is sometimes ordered with the Upper GI (UGI) in which the patient must be NPO...
68
What are some indications for an Upper GI (UGI) examination?
hiatal hernia reflux ulcers tumors vomitting hematemesis
69
What are some contraindications for an Upper GI (UGI) examination?
aspiration nausea/vomitting bowel obstruction (distal obstruction) constipation
70
What is the patient prep for the Upper GI (UGI) exam?
NPO (a must) Patient will be rescheduled if not!
71
What is a Small Bowel Follow Through (SBFT/SBS) Examination? Is it fluoroscopy or regular xray?
a transit study of the small bowel. a series of images are taken to show how fast (or slow) contrast is progressing through the small bowel. It is a series of regular supine abdomen x-rays. The ileocecal valve (end of the small bowel) is hidden in a mess of bowel. Only then will the radiologist enter the exam to palpate the RLQ under fluoroscopy to open up the area for evaluation.
72
What imaging contrast is used in the small bowel follow through exam?
thin barium iodinated contrast (2nd choice compromised patient)
73
What is a common complication with administering oral contrast?
Barium tastes like chalky shit Iodinate contrast (gastroview) taste like oily shit
74
What are indications for the small bowel follow through examination?
motility of small intestine dueodenum jejunum ileum obstruction ileus intramural lesions Crohn's disease
75
What is the patient prep for the small bowel follow through examination?
NPO 8 hours
76
What is a common complication of the small bowel follow through exam?
transit time can be very lengthy. some exams can last over \>1-5 hours. I've had patient's go home and come back the next day.
77
What is a Barium Enema (BE) exam?
it is a contrast study of the large intestine.
78
What imaging contrast can be used for a Barium Enema.
Barium Sulfate (single contrast) OR Dual contrast: Barium Sulfate and Air (introduced rectally) Don't let the name fool you! just like all other fluoro GI exams, iodinated contrast (gastroview) can be used in compromised patients instead of barium.
79
What are indicated for the Barium Enema Examination?
visualize entire large bowel through retrograde filling. Diverticulosis polyps tumor masses
80
Can a barium enema be done with oral contrast administration? Can the small bowel examination be done with retrograde filling?
No... it must be done with retrograde filling No... contrast in the small bowel should not be visualized on the barium enema examination. Barium in the small bowel would mean a compromised ileocecal valve.
81
What is the patient prep for the barium enema study.
Bowel prep (enemas as indicated by department protocol) NPO
82
What is an Intravenous Pyleogram? Is it a fluoroscopic examination?
It is a imaging study of the urinary system. It is not a fluoroscopic examination. it is a series of supine abdomen images taken at various timed sequences.
83
is oral contrast used in an Intravenous Pyelogram study?
No... oral contrast will conceal the IV contrast filtering through the urinary system.
84
What Imaging contrast is used in the Intravenous Pyelogram Study?
Iodinated IV contrast.
85
What is the patient prep for the Intravenous Pyelogram study?
bowel prep of laxatives (stool patterns can conceal IV contrast filtering through the urinary system) NPO 12 hours prior to exam
86
What are the indications for the Intravenous Pyelogram study?
visualization of urinary system. structural changes due to obstruction of flow (i.e. stone, tumor)
87
Contraindications to the Intravenous Pyelogram study?
allergy to the iodinated IV contrast. compromised kidney function (elevated BUN Creatnine)
88
Why is IV contrast the best imaging contrast for the Intravenous Pyelogram?
The body doesn't need the IV contrast, therefore it is quickly filtered out of the body through the urinary system.
89
You are viewing an image taken during an IVP. You see a normal appearing right kidney with contrast filling the total right ureter. The bladder is enhanced suggesting that some contrast has entered the bladder as well. The left kidney looks different than the right, the renal calyxes look blunted and enlarged in comparison to the right. You see only partial filling of the left ureter. What could you conclude?
Obstruction of the left ureter possibly due to stone or stricture (tumor)
90
Iodinated contrast can take two different forms, what are they?
Oral (gastroview, gastrograffin) Iodinated oral contrast is oily, bitter tasting, and non sterile. IV (Omnipaque, visipaque, many others) Iodinated IV contrast is sterile, viscous (sticky). It is an injectable water-soluble solution with suspended iodine particles throughout. It is never used as an oral contrast but will also be used in contrast enhanced studies of body orifices (uterus, fallopian tubes, fistulas).
91
CT Chest with Contrast: What areas are the body are imaged?
Slices of the thorax starting just above the lung apices through the adrenal glands. Lungs, vascular structures, pleura, upper abdomen
92
CT Chest with Contrast: What does "with Contrast" mean?
iodinated IV contrast will be used. The contrast will enhance normal vascular structures and abnormalities that have blood supply.
93
What are indications for a CT Chest with Contrast?
Lung mass Lung disease General Survey Pleural effusion Trauma
94
Will/Can you order a CT Chest without contrast?
rarely... it was not discussed in lecture. It is an alternative if the patient has severe allergy to iodine. Sometimes can be ordered for special procedures...
95
What is the routine order for a Chest CT?
CT Chest with Contrast
96
What are some pathological conditions that can be seen on Chest CT?
Cancer, Pneumonia, pleural and pericardial effusions, pneumothorax, hemothorax
97
What imaging study should be done before a Chest CT?
routine chest x-ray
98
When should a CT Angiography study be ordered instead of the CT Chest with Contrast?
Embolism or Aneurysm any time your primary focus in on vascularity
99
Lung windows are an algorithm that is applied to the display of the CT workstation. What is the benefit of the lung window versus the soft tissue window?
The display of the lung window will show the lungs parenchyma with greatest detail. The soft tissue will display as washed out and white. (slide 26 in Clinicians Guide to CT differentiates window leveling types)
100
What are indications for CT Angiography of the Chest?
embolism or aortic aneurysm symptoms: Chest pain, SOB, post-op respiratory changes
101
What type of imaging contrast is used for CT Angiography of the Chest? How is it same/different from CT Chest with Contrast?
The same iodinated IV contrast is used. The difference is the rate (bolus) at which it is administered. It is administered faster and will have a greater concentration in the blood that enhances the vascular structures with precision.
102
In addition to the anatomy identified in the CT Chest with Contrast examination, what anatomy will be enhanced on the CT Angiography Chest?
Heart Aorta (and branches) Pulmonary Arteries
103
What are some pathological conditions seen on the CT Angiography Chest?
Pulmonary Embolism Aneurysm Dissection as well as: Cancer Pneumonia Pleural and Pericardial effusions Pneumothorax Hemothorax
104
What is a alternative imaging test to the CT Angiography Chest when contrast is contraindicated?
Ventilation-Perfusion Study A VQ Scan is done in Nuclear Medicine and will only diagnose pulmonary embolism... it does not evaluate the aorta or other vascular structures of the chest.
105
What types of CT examinations can be performed on abdomen/pelvis?
~CT Abd/Pel without contrast ~CT Abd/Pel with contrast ~CT Abd/Pel with and without contrast
106
What are indications for the CT Abd/Pel with Contrast?
Pain Nausea Vomiting Distention Cancer
107
What is the scan area of the CT Abd/Pel with Contrast?
Above the diaphragm through the symphysis pubis. The abdomen is from the diaphragm to the iliac crest. The pelvis is from the iliac crest to the symphysis pubis. This is the same scan area for all types of CT abd/pel. The abdomen and pelvis are almost always scanned at the same time... it is VERY rare to do just one.
108
What are some pathological conditions that can be seen on the CT Abd/pel with Contrast?
Cancer Chrohn's dx Small bowel obstruction colitis appendicitis Cirrhosis Laceration Lymphoma Pancreatitis Gallstones (U/S preferred) Hernia
109
What imaging test would you order if you wanted to evaluate the abdominal aorta with CT?
CT Angiography Abdomen and Pelvis
110
What imaging test would you order if your patient complained of flank pain, hematuria and a history of kidney stone?
CT Abd/Pel without contrast
111
Why is contrast not used when evaluating the abdomen/pelvis for kidney stones on CT?
The contrast collected in the urinary system has a similar density as a stone. Therefore, the contrast will conceal the stone.
112
In the exams name, what type of contrast does "with contrast" or "without contrast" indicate?
IV contrast
113
What is an indication for CT Angiography Abdomen Pelvis?
known or suspected aneurysm of the abdominal aorta (and it's branches)
114
What are alternative imaging tests to the CT Angiography Abd/Pel?
MR Angiography (done in MRI) Ultrasound Aorta
115
What are clinical indications for CT Spine?
pain trauma injury
116
What anatomy is seen in the CT Spine?
All boney anatomy and spinal cord in the spinal section scanned
117
What are common pathologies seen in CT spine?
Fractures Lesions Subluxations Spinal Stenosis
118
When is MRI of the Spine preferred over CT of the Spine?
mass lesions
119
What is CT Myelogram?
CT of the Spine is performed after administration of an iodinated contrast is injected into the subarachnoid space and bathes the spinal cord (slide 42)
120
What is the Federal regulatory principles concerning radiation exposure?
Any dose of radiation might cause cancer.
121
What are effects of radiation damage to the cell?
cell death cell survival with no harm cell survival with mutation
122
What are some deterministic effects of radiation that are associated with radiation dose thresholds?
Usually seen in VERY large doses, not in diagnostic imaging (i.e. chernoble) Radiation-induced abortion Cataract formation Sterility Hair Loss Skin Erythema Death
123
What are common cancer types associated with radiation exposure.
Leukemia Thyroid Cancer Breast Cancer Lung Cancer Bone Cancer Skin Cancer
124
What are radiation reduction methods in CT?
~appropriateness of exam ~consider alternative exams ~prior study performed with same information ~radiation dose history
125
Who is responsible for weighing the benefit vs risk of radiation exposure?
Ordering provider
126
Regarding radiation safety, the CT examination should not be repeated without:
clinical justification and should be limited to the area of interest. for example: Do not order a CT Cervical, Thoracic and Lumbar spine when the lumbar spine is the area of interest.
127
Who is the ACR and what do they do?
American College of Radiology They set appropriateness criteria for procedures and have resources available online. They are a GREAT resource for clinicans and all imaging protocols are based on these principles.
128
What imaging modality has the highest radiation exposure to the patient?
Computerized Axial Tomography (CT Scan)
129
What imaging modalities (discussed in this unit) have no radiation exposure?
Magnetic Resonance Imaging (MRI) Ultrasonography (U/S)
130
What imaging moadlities (discussed in this unit) have radiation exposure? Rank highest to lowest...
CT Scan Fluoroscopy X-ray
