Intro to Radiology and Chest Xrays Flashcards Preview

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Flashcards in Intro to Radiology and Chest Xrays Deck (132)
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1
Q

Xray advantages and disadvantages

A

advantage- fast, low radiation

disadvantage- poor soft tissue eval.

2
Q

Chest radiography seems warranted in ARI when one or more of the following are present

A
  1. older than age 40
  2. dementia
  3. a positive physical examination
  4. hemoptysis
  5. associated abnormalities (leukocytosis, hypoxemia)
  6. or other risk factors, including CAD, CHF, or drug-induced acute respiratory failure.
3
Q

types of nuclear medicine scans

A

VQ scan
bone scan
thyroid uptake
cardiac stress test

4
Q

Pros of CT

A
  1. allows simultaneous visualization of many structures
  2. no superimposition of structures
  3. can be viewed in several planes (axial, coronal, sagittal)
  4. Quicker than MRI (LESS movement artifact)
  5. HIGHER spatial resolution than MRI
5
Q

CONS of MRI

A
  • VERY sensitive to movement (have to hold breath)
  • SLOW
  • VERY loud and claustrophobic
  • does not image bone well
  • gadolinium reaction
  • multiple contradictions (cannot have metal in body)
6
Q

how does a computed tomography (CT) work?

A
  • a rotating beam of xrays is passed through patient and picked up by MULTIPLE detectors (motorized table)
  • evaluated by a computer and converted to 2D slices
  • data can be manipulated to generate various types of slices or to highlight various structures
7
Q

when assessing lucencies and densities on X-ray and you see an abnormal finding, check for:

A
  1. normal anatomy
  2. structure formed by superimposition of 2 structures
  3. artifact due to inaccurate positioning
  4. true pathologic lesion
8
Q

fluid from the circulatory system (out of capillaries)

A

exudates

9
Q

what should you see w/ a lateral chest xray

A
  • AP window
  • Retrosternal airspace
  • Lower 1/3 of sternum should be in contact w/ R ventricle
  • CVA is most dependent position in upright film
10
Q

what is the first line therapy for a bilateral aspiration pneumona

A

clindamycin 450-900 mg IV q8 hours

11
Q

what type of imaging is ionizing?

A

Electromagnetic Radiation: Xrays, CTs

Particle Radiation: Nuclear medicine- bone scan, VQ scan, thyroid uptake, thallium cardiac stress, PET scan, fluoroscopy

12
Q

common DDX for hip effusion in a 0-3 y/o

A

septic hip
hip dysplasia
occult fracture
length discrepancy

13
Q

why would one want a lordotic chest xray?

A

better visualize structures in the thoracic apex obscured by overlying bone strutures
(ex. see apex of lungs better)

14
Q

what workup would you do for a limping child

A
  • 1st plain film- fx or foreign body
  • possibly then:
  • US: hip effusion- infection or transient synoviti- post viral
  • MR: myositis, osteomyelitis, absess
  • bone scan: osteomyelitis, bone mets
15
Q

terms used for “black” on Xray, CT, MRI, US, nuclear medicine imaging

A
Xray- lucent
CT- decreased attenuation
MRI- decreased signal intensity
US- decreased echogenicity
Nuclear Medicine-increased tracer uptake
16
Q

Silhouette/structure:

left heart border

A

lingula (anterior of left lobe)

17
Q

how to assess level of inspiration on chest xray

A
  • counting ribs
  • 9 posterior ribs (angle downward)
  • 7 anterior ribs
  • heart shadow should not be hidden by diaphragm
  • on an upright PA radiograph projecting above the diaphragm would be satisfactory
18
Q

what are signs of a pneumothorax?

A
  1. visualization of visceral pleural line (MUST FOR DX)
  2. convex curve of the visceral pleural line paralleling the contour of the chest wall
  3. absence of lung markings distal to the visceral pleural line (most times)
  4. Cardiac or hemidiaphragm shift
  5. deep sulcus sign on supine radiograph
19
Q

what % of CTs are done with contrast?

A

75%

20
Q

what is penetration in chest xray interpretation?

A
  • refers to adequate photons traversing the patient to expose the radiograph
  • limited in pts of large size such that there is poor visualization of structures in the lower lung fields and in retro-cardiac location
21
Q

what type of images are affected by excess fat

A

Fat and CT = great!
Fat and US= bad (obstructs image)
Fat and MRI= doesn’t affect image

22
Q
  • If spinous process appears closer to the right clavicle, the patient is rotated toward their _____
  • If spinous process appears closer to the left clavicle, the patient is rotated toward their _____
A
  • own left side
  • own right side

*inverse relationship (if RIGHT clavicle is CLOSER, than it is rotated to the LEFT)

23
Q

what is the best view to confirm the presence of pleural effusion?

A

decubitis, then lateral, then AP/PA

-bc its gravity dependent and shifts w/ position

24
Q

normal anatomic landmarks of Chest PA and lateral view

A
  1. trachea
  2. carina
  3. aortic arch
  4. heart
  5. costophrenic angles
  6. hilum*
  7. diaphragm
25
Q

indications for a bone scan

A
  • screening for metastasis to bone
  • stress fracture and other occult skeletal trauma
  • early osteomyelitis
  • early avascular necrosis
26
Q

Rank these imaging modalities from least to most effective radiation dose:
CT abdomen and pelvis w/ and w/o contrast, CT abdomen and pelvis, CT chest, chest xray, Coronary CTA, PET scan

A
Chest xray (~10days)
Chest CT (~2 yrs)
CT abdomen and pelvis (~3yrs)
Coronary CTA (~4 yrs)
CT abdomen  and pelvis w/ and w/o contrast (~7yrs)
PET Scan (~8 yrs)
27
Q

4 basic densities for CT

A
  1. Air (darkest)
  2. Fat
  3. Soft tissue
  4. Bone (white)

*Contrast appears WHITE on images

28
Q

disadvantage of MRA

A
  • resolution generally inferior to CT catheter angiogram

- does not image calcium or small vessels well

29
Q

what is the difference between ionizing and non-ionizing radiation

A

Ionizing radiation breaks chemic bonds (DNA)

*but with any radiologic study we are adding energy into the person

30
Q

Silhouette/structure:

upper right heart border/ascending aorta

A

anterior segment of RUL

31
Q

what planes can CTs be viewed in?

A

coronal- front and back
sagittal- R and L
axial- top and bottom

32
Q

main components of a radiology report

A
  1. patients demographics. (name, DOB, SSN, etc.)
  2. relevant clinical info and ICD-9 code
  3. Findings (description of study results)
  4. impression (conclusion or diagnosis)

*recommends = want you to do!

33
Q

form when there is increased capillary Hydrostatic pressure or decreased osmotic pressure

A

transexudate

34
Q

work up for Chest pain

A
  • start w/ CXR

- if normal determine if need CT (cysts) or cardiac cath, etc, based on clinical presentation/hx

35
Q

describe the fissures of the lungs

A
  1. Major oblique fissure- separates the LUL and LLL
  2. Right Major fissure- separates the RUL/RML from RLL
  3. Right minor fissure- separates the RUL from RML
36
Q

what imaging things would you never do in a trauma?

A
  • MRI bc it takes too long and pt may be unstable

- PO IV

37
Q

Silhouette/structure:

upper left heart border

A

anterior segment of left upper lobe (LUL)

38
Q

how to assess the mediastinum on chest xray

A

assess width and contour

  • lower margin of the left hilum is at upper margin of right hilum (typically higher on L bc heart takes up space and pushes it up)
  • higher density is symmetrical
39
Q

why is contrast material used in MRI

A

to enhance blood vessels, most often in conjuction w/ brain imagine

40
Q

The cardiac border or silhouette will appear larger on ____ radiograph due to the magnification effect of the more anteriorly located heart relative to the film.

A

an AP

41
Q

what are the pre-read steps for chest xray interpretation?

A
  1. name/ date
  2. obtain old films to compare
  3. what type of view(s)
42
Q

what is the difference between cold and hot nodules in a thyroid uptake scan

A

cold nodules (decreased uptake) are more concerning and require biopsy

43
Q

MR contrast is associated w/ contrast reaction in who?

A

pts w/ severe renal failure (stage 4 or 5; GFR less than 30mL/min/1/73m2)–> causing development of the rare inflammatory disease nephrogenic systemic fibrosis

44
Q

how does an ultrasound work?

A
  • High-frequency sound waves are transmitted into the patient and the “echoes” of this emitted sound are picked up by a detector
  • 2D image is generated based onthe strength and timing of the sound echoes
  • Doppler US uses the Dopplerprinciple to detect and measure blood flow
  • *NIVA-noninvasive vascular assessment
45
Q

PROs of MRI

A
  • non-ionizing radiation
  • good for soft tissues ex. cartilage assessment (compared to CT)
  • allows simultaneous visualization of many structures
  • no superimposition of structures
  • can be viewed in several planes
46
Q

Things to look w/ joints on xrays

A
  • articular cortex
  • articular cartilage
  • synovial fluid
  • symmetrical joint space
  • bone spurs
47
Q

what is the difference between the parietal pleura and the visceral pleura?

A
  • parietal: lines inside of thoracic cage- constantly reabsorbing and set through lymphatic system
  • Visceral: adheres the surface of the lung- constantly producing fluid
48
Q

what is “background” radiation?

A
  • the radiation an avg person gets per year (~3 mSv per yr)

- depends on altitude (~1.5mSv more per yr in Colorado)

49
Q

how do you order a CXR looking for line placement

A
  • tell them where you placed the line!!

- EG tube should be on left side in stomach NOT through bronchus

50
Q

what could cause a promient right atrium on an AP radiograph?

A

pt is rotated to their right side (left shoulder forward)

51
Q

A routine x-ray assessment of extremities includes looking at…..

A
  1. soft tissues
  2. contour of each bone
  3. joints: articular space, joint space
  4. is anatomy normal?
  5. Lucencies/densities
  6. Location of lesion (requires orthogonal views)
52
Q

ddx for widen mediastinum on CXR

A
  • aortic dissection
  • connective tissue disease
  • lymphoma
  • infection, TB
53
Q

Almost all pleural effusions first collect in ____

A

a subpulmonic location beneath the lung

54
Q

what are radiograph plain film images formed by?

A

penetration of xrays through tissue or other substances

- degree of penetration depends on density and thickness

55
Q

What does a pneumoperitoneum look like on CXR?

A

CRESCENTIC lucency that parallels the undersurface of the RIGHT hemidiaphragm

*size proportional to volume of air

56
Q

5 basic densities for X-ray

least to most

A
  1. Air
  2. Fat
  3. Water (soft tissue and blood–highly vascular tissue)
  4. bone (calcium)
  5. Metallic objects (contrast material)

*Darkest to lightest

57
Q

types of radiation

A
  1. Electromagnetic
  2. Particle
  3. Acoustic
  4. Gravitational
58
Q

what is inspiration in chest xray interpretation?

A

the volume of air in the hemithorax will affect the configuration of the heart w/ question of cardiac enlargement w/ a shallow level of inspiration

59
Q

things to consider when ordering an imaging study

A
  • cost
  • risks (radiation)
  • burden
  • why are you doing the study
  • indication driven imaging
60
Q

what is a bone scan?

A

-Technetium-99m attached to a phosphate compound, is administered IV and is rapidly incorporated into newly forming bone
-areas of increased bone metabolism appear BLACK
(nuclear med)

61
Q

common DDX for hip effusion in a 11-16 y/o

A
SCFE
AVN
overuse
Tarsal coalition
CG arthritis
62
Q

why are children more sensitive to ionizing radiation then adults?

A

bc their cells are rapidly dividing, they are at increased risk for damage from the radiation

63
Q

what is a VQ scan (ventilation/perfusion scan)

A
  • Technetium-99m attached to albumin microaggregates, administered IV and is trapped in pulmonary capillaries
  • ventilation is evaluated by a lung scan following inhalation of a radioactive gas (xenon, others)
  • 2 scans are compared for VQ mismatch
64
Q

Describe how an X-ray works

A

X-rays (ionizing radiation) is transmitted through the patient onto:
-a fluorescent screen that emits light, exposing a film
-a detector that converts the energry into a digital image
(xray source, object, detector/film)

65
Q

abdomen structures to assess on chest xray

A
  • liver
  • stomach bubble
  • splenic flexure of colon
  • diaphragm
66
Q

when is chest radiography indicated for someone w/ exacerbation of COPD (including asthma)

A

not typically indicated unless:
-suspected complication such as pneumonia or pneumothorax
OR
-unless one or more of the following are present: leukocytosis, chest pain, edema, or a hx of CAD or CHF

67
Q

how does nuclear medicine work?

A
  • a radioactive material w/ short halflife is given, usually IV (Technetium-99m)
  • concentration in tissues or organs is measured w/ a gamma camera
  • uptake of specific organ can be assessed
68
Q

what is the orientation of CT (and MR) axial images

A

imagine you are standing at the foot of the supine patient

69
Q

indications for US

A
  1. Fluid-filled structures (cysts)
  2. Breast abnormalities
  3. Hernias
  4. Gallbladder disease
  5. DVT
  6. Prostate (transrectal)
  7. Uterine fibroids
  8. Poor circulation, claudication
  9. Obstetrics (abdominal or transvaginal)
  10. ovarian torsion or testicular torsion
  11. ascites
  12. hydronephrosis
  13. masses
70
Q

what is magnification in chest xray interpretation?

A

making reference to the position of the patient and the xray beam

71
Q

what is an air bronchogram?

A

a tubular outline of an airway made visible by filling of the surrounding alveoli by fluid or inflammatory exudates

*indicates air space disease with fluid density outlining the air-filled bronchi

72
Q

what is exudate most commonly seen with?

A

malignancy

73
Q

DDX for severe RLQ in a female with possible imaging/work up

A
  • appendicitis- US in kids, CT w/ contrast or MRI in adult (if preg.)
  • constipation- PE and possible plain film
  • Ovarian torsion- US is key!!
74
Q

Silhouette/structure:

anterior hemidiaphragm

A

lower lobes (anterior)

75
Q

thorax (soft tissues, and bone) structures to assess on chest xray

A
  • ribs
  • coracoid process and acromium process
  • carina
  • trachea
76
Q

indications for a thyroid uptake scan

A

thyroid nodules

77
Q

Silhouette/structure:

Right heart border

A

Right middle lobe (medial)

78
Q

what is CT contrast made of?

A

Iodine-based and carries that risk of contrast ractions

79
Q

How much air is required to see a pneumothorax on a chest radiograph?

A

about 500ml

80
Q

how do you assess rotation of the chest radiograph

A
  • judging the position of the clavicle heads and the thoracic spinous process
  • Ideally the clavicle heads should be equidistant from the spinous process.
81
Q

What is a HIDA (hepatobiliary iminodiacetic acid) scan?

A

Technetium-99m labeled HIDA, administered IV and is taken up selectively by hepatocytes and excreted into bile
-the test is positive if the gallbladder does not visualize, which is due to cystic duct obstruction, usually from edema associated w/ acute cholecystitis or an obstructing stone

82
Q

types of acoustic radiation

A

ultrasound, sound, seismic

83
Q

what is the standard way to order a chest xray and why?

A
  • PA w/ corresponding lateral bc it will give appropriate magnification of the heart
  • portable radiographs are typically bc pt cannot stand (heart appears larger)
84
Q

why would contrast material be used in CT?

A

used to enhance blood vessels, GI tract, or renal/urinary collecting system

85
Q

what is a MRA

A
  • MRI used to image blood vessels
  • typically no contrast is needed but gadolinium may be used for image enhancement
  • often used in place of more invasive and more expensive CT catheter angiogram (carotid arteries, intracranial arteries, large vessels for aneurysm)
86
Q

degree penetration depends on what?

A

density and thickness

87
Q

CT- to contrast or NOT to contrast for Chest, Abdomen/pelvis, head

A
  • Chest: NON-constrast- except pulmonary nodules, interstitial disease, PE
  • Abdomen/Pelvis: Contrast- except kidney stones
  • Head: NONcontrast is routine
88
Q

how to assess ideal penetration

A
  1. thoracic spine should be barely perceptual viewing the cardiac silhouette
  2. see ribs through heart
  3. see pulmonary vessels nearly to the edges of the lungs
89
Q

what are the findings/search pattern steps for chest xray interpretation?

A

Are There Many Lung Lesions

  1. abdomen
  2. thorax (soft tissues bones)
  3. mediastinum
  4. lung- unilateral
  5. lung- bilateral
90
Q

common DDX for hip effusion in a all ages

A
septic arthritis
Osteomyelitis
cellulitis
stress fx
neoplasm
neuromuscular
91
Q

what type of imaging is non-ionizing?

A

Electromagnetic Radiation: Magnetic Resonance (MR)

Acoustic Radiation: ultrasound

92
Q

what is the difference between density and lucency with X-rays?

A

density- “bright” opaque, object which inhibits transmission of xray beam (ex. bone)
Lucency- “dark”, allows transmission of xray beam (ex. air)

93
Q

what type of movement can be seen w/ fluoroscopy?

A
  • reflux
  • peristalsis
  • aspiration
94
Q

what is fluoroscopy?

A
  • “real-time” x-ray

- higher radiation exposure than plain film x-ray (ionizing)

95
Q

what can poor rotation on a chest xray cause?

A
  • distorts mediastinal anatomy and makes assessment of cardiac chambers and the hilar structures especially difficult.
  • Chest wall tissue also contributes to increased density over the lower lobe fields simulating disease
96
Q

what is a thyroid uptake scan?

A

technetium-99m pertechnetate, administered IV and is taken up by follicular cells of thyroid

  • many benign and almost all malignant nodules do NOT concentrate radioiosotpes as well as normal tissue
  • looking for cold vs hot nodules
97
Q

uses of PET scans

A
  • detection of CA and evaluation of responses to treatment
  • assessment of CAD
  • management of epilepsy
  • evaluation of dementia
98
Q

terms used for “white” on Xray, CT, MRI, US, nuclear medicine imaging

A
Xray- density
CT- increased attenuation
MRI- increased signal intensity
US- increased echogenicity
Nuclear medicine- decreased tracer uptake
99
Q

when is fluoroscopy used?

A
  • GI: barium swallow, barium enema
  • Ortho: hardware placment, fracture reduction
  • CV: angiography
  • Other: PICC line placement, pacemaker, ICDs, hiatal hernia, GERD, aspiration, TE fistula, bilious vomiting
  • Enema: lower obstruction
100
Q

CONs of CT

A
  1. Higher dose of x-rays (CT of abdomen/Pelvis= 500 chest xrays)
  2. risk of contrast reaction
  3. Cost
  4. artifact w/ certain anatomical regions (posterior fossa)
101
Q

indications for a VQ scan

A

suspect pulmonary embolus

102
Q
  • Posterior costophrenic sulcus blunting usually occurs with approximately ____ of fluid
  • Decubitus views of the chest can demonstrate effusions as ___- __ mL
A

75 mL

15 to 20 mL

103
Q

essential components of a radiology request

A
  1. patient ID
  2. study to be conducted
  3. Clinical history – ordering w/ symptoms NOT dx and pertinent clinical context)– give how trauma happen so that one can think about mechanism of injury
  4. reason for study (give DDX but dont say “rule out” “routine” or “pre-op”
  5. requesting provider w/ phone/pager number
104
Q
what do the following mean in radiologist reports?
"recommend"
"consider"
"Query"
"paucity bowel gas"
"no radio opaque FB"
A

“recommend”- DO IT
“consider”- F/U for further eval if needed
“Query”-i think there is
“paucity bowel gas”- no air. (could be fluid)
“no radio opaque FB”- No metal, coin, leaded gases.. DOES NOT include plastic, wood, food, paper, etc.

105
Q

types of particle radiation

A

alpha, beta, neutron (particles of non-zero rest energy)

106
Q

The vascular pattern in the lung fields will be accentuated with a _____ since the same amount of blood flow is now distributed to a smaller volume of lung.

A

shallow inspiration

107
Q

13 step program to chest xray reading consists of what?

A
  1. pre-read (1-3)
  2. Quality control (PIRMA) (4-8)
  3. findings/ search pattern (9-13)
108
Q

causes of pneumothorax

A
  • pleural blebs
  • Bullae
  • emphysema and interstitial lung disease
  • Traumatic and iatrogenic causes include penetrating wounds, line placements, lung biopsies and mechanical ventilators.
109
Q

how does lack of penetration appear on xray

A

“whiter”
-can simulate pneumonia or effusion

*over penetration= dark

110
Q

how does an MRI work?

A

-A magnetic field is used to align atoms in the body.
When the magnetic field is released, atoms emit radio
frequency radiation
 -Radiofrequency radiation (nonionzing) emitted from the tissues is picked up by multiple detectors and processed by a
computer to generate 2D “slices”.

111
Q

common DDX for hip effusion in a 4-10 y/o

A

JRA
toxic synovitis
legg-calve-perthes

112
Q

what does COPD look like on a CXR?

A

f-latten diaphragm

  • increased rib count
  • a LONG NARROW heart
113
Q

what are the quality control steps for chest xray interpretation?

A

PIRMA

  1. penetration
  2. inspiration
  3. rotation
  4. magnification
  5. angulation
114
Q

Silhouette/structure:

aortic knob

A

apical portion of LUL (posterior)

115
Q

types of electromagnetic radiation

A

radio waves, visible light, microwaves, x-rays, gamma radiation

116
Q

what are causes of pneumoperitoneum

A
  1. rupture of bowel
  2. Peptic ulcer
  3. diverticula
  4. appy
  5. carcinoma
  6. trauma
  7. 5-7 days AFTER abdominal surgery
117
Q

when would you get a HCT in a trauma case in:

  • a kid less than 2
  • a kid older than 2
A

less than 2: altered mental status, severe mechanism (MVA + ejection, death of another passenger, rollover, fall more than 0.9m, etc.)

older than 2: severe mechanism (MVA + ejection, death of another passenger, rollover, fall more than 1.5m, etc.)

118
Q

CONS of PET scans

A
  • VERY expensive

- HIGH ionizing radiation dose

119
Q

what is MR contrast made of?

A

typically gadolinium

120
Q

6 causes of an air bronchogram

A
  1. lung consolidation
  2. pulmonary edema
  3. nonobstructive pulmonary atelectasis
  4. severe interstitial disease
  5. neoplasm
  6. normal expiration
121
Q

what is a salter fx

A

goes through both sides of growth plate

122
Q

what is a PET (positron emission tomography) scan

A
  • uses various radiolabeled compounds to evaluate chemical and physiologic function
  • evaluates function , not structure
  • HIGH ionizing radiation!
123
Q

Indications for HIDA scan

A
  1. cholestasis (burning hands and feet)
  2. suspected acute cholecystitis (RUQ pain, N/V)
  3. post surgical evaluation of the biliary tract
  4. demonstrating patency of the common bile duct and ampulla
124
Q

what is transexudate most commonly seen with?

A

CHF or cirrhosis

125
Q

what is the difference between T1-weighted and T2-weighted MRI images?

A

T1-weighted: contrast is white, bone is black

T2- weighted: contrast is black, bone is white

126
Q

how does a lordotic xray appear different than a PA or AP angle?

A

beam is angled up toward head so:

  • unusually shaped heart
  • clavicles will project superiorly relative to upper thorax (distortion of normal mediastinal anatomy)
  • more horizontal rib orientation
127
Q

what imaging is best for organ laceration

A

CT w/ contrast

*can tell if there is active bleeding too

128
Q

compare the radiation of a nuclear medicine procedure to that of a diagnostic x-ray

A

about the same

-both ionizing radiation

129
Q

what does pneumocystis carinii pneumonia (PCC) look like on CXR?

A

diffuse bilateral interstitial infiltrates (80-95%)

a fungal pneumonia commonly seen in pts w/ aids/HIV

130
Q

how to assess for good angulation in a chest xray?

A

clavicles should lay over 3rd-4th rib and have an S shaped appearance

131
Q

pneumothorax are most commonly seen in what type of people?

A

tall, skinny, smokers, (young)

132
Q

what does a trauma series include?

A

plain film of chest, pelvis, and lateral spine