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Introduction to Medical Imaging

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Introduction to Medical Imaging Jeff Benseler, D.O. Objectives Medical Imaging: What to expect in your first 2 years at OUHCOM Overview: How do x-rays create an image ... – PowerPoint PPT presentation

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Title: Introduction to Medical Imaging


1
Introduction to Medical Imaging
  • Jeff Benseler, D.O.

2
Objectives
  • Medical Imaging What to expect in your first 2
    years at OUHCOM
  • Overview How do x-rays create an image of
    internal body structures?
  • What are the advantages of CT, MRI and
    Ultrasound?

3
Medical Imaging (Radiology)
  • Nearly all medical disciplines utilize medical
    imaging
  • As you move from block to block we will learn
  • How each modality works to create an image of
    internal body structures
  • Selecting the best imaging tests for a given
    clinical presentation
  • Develop a stepwise repeatable pattern of
    evaluating medical images

4
Method for learning medical image interpretation
  • Most blocks will contain recorded presentations
  • These recordings last approximately 10 to 30
    minutes each
  • Most blocks will have 2 to 4 recordings to view
    before the live class
  • The recordings can be viewed and reviewed as
    needed anytime 24/7
  • In class, we will learn by interpreting unknown
    cases

5
Questions about medical imaging
  • Please feel free to contact me with questions
  • My preferred contact method is email
  • benseler_at_ohio.edu

6
Objective 2
What are x-rays?
  • No mass
  • No charge
  • Energy

X-rays are a type of electromagnetic energy
7
How do x-rays passing through the body create an
image?
  • X-rays that pass through the body render the
    image dark (black)
  • X-rays that are totally blocked render the image
    light (white)
  • Air low atomic x-rays get through image
    is dark (black)
  • Metal high atomic x-rays blocked image is
    light (white)

8
5 Basic Radiographic Densities
1.
  • Air
  • Fat
  • Soft tissue/fluid
  • Mineral
  • Metal

4.
5.
2.
3.
Name these radiographic densities.
9
Optimal environment for visual perception
  • Dedicated source of light (5 to 9 mega pixel
    monitors)
  • Darkened environment (like a movie theater)
  • Limit distraction

10
X-ray viewing station
11
Can you recognize shapes and density?
12
Find the pathology What clues do you have?
13
Medical Imaging Interpretation3 basic steps
  • First learn how each modality creates an image of
    internal body structures
  • Next, be able to accurately label normal anatomy
    (body structures)
  • Then, search for structures that dont belong and
    for body structures that are abnormal in size,
    shape, position and/or density

14
History 11 year old twisting injury of the foot
15
(No Transcript)
16
Naming the parts of a long bone
Distal
3.
2.
1.
Proximal
Word bank epiphysis, metaphysis, diaphysis,
cortex, medullary cavity
17
Review What are the 5 basic radiographic
densities from black to bright white?
  • Air
  • Fat
  • Soft tissue/fluid
  • Bone/mineral
  • Metal

18
Summary for objective 2 How do x-rays create an
image of internal body structures?
  • X-rays pass through the body to varying degrees
  • Higher atomic number structures block x-rays
    better, example bone
  • Lower atomic number structures allow x-rays to
    pass through, example air in the lungs

19
Objective 3Advantages of CT, MRI and Ultrasound
  • These modalities are cross sectional imaging
  • Cross sections are like slices
  • X-ray studies are a 2 dimensional representation
    of 3 dimensional structures can result in
    undesirable overlapping densities and artifacts

20
CT
  • Advantages
  • Eliminates overlapping densities
  • Excellent resolution
  • Excellent for detecting intracranial bleeding
  • Excellent in the neck, chest and abdomen
  • Excellent for evaluating fractures
  • Disadvantages
  • More expensive than x-ray and ultrasound
  • Much more radiation
  • Dense bone (petrous ridge for example) and metal
    cause severe artifacts

21
air
CT scan of the abdomen
X-rays used
skin
What density is this?
22
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23
MRI
  • Advantages
  • No overlapping artifact
  • Excellent resolution
  • Very good at detecting fluid
  • Excellent for imaging the brain, spine and joints
  • No radiation
  • Multiple imaging tests within the same study (T1,
    T2, IR, GE)
  • Disadvantages
  • Very expensive
  • Patients cannot have a pacemaker or ferromagnetic
    material
  • Slower to acquire images
  • (approximately 45 minutes)

24
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25
Ultrasound
  • Advantages
  • No radiation
  • Portable
  • Instantaneous (real time)
  • Excellent for cysts and fluid
  • Doppler ultrasound is excellent to assess blood
    flow
  • Excellent for newborn brain, thyroid, gall
    bladder, female pelvis, scrotum, pregnancy
  • Disadvantages
  • Does not work well in large or obese patients
  • Resolution less than CT and MRI
  • Air or bowel gas prevents visualization of
    structures

26
Ultrasound of the gall bladder showing a gall
stone
27
X-rays, CT, MRI and ultrasound help us see into
the body
  • Internal body structures are composed of varied
    material (fat, muscle, bone, gland) or contain
    air, water or minerals that show up differently
    on each type of imaging test.
  • Each modality has its own advantages allowing us
    the choose the best one for each medical
    circumstance.

28
What an excellent medical student at your level
can do
  • Be able to describe how x-rays can create an
    image of internal body structures
  • Recognize and label the 5 basic densities on an
    x-ray
  • Be familiar with the advantages for CT, for MRI
    and for ultrasound

29
List of Potentially HelpfulRadiology Websites
  • http//www.med-ed.virginia.edu/courses/rad/
  • Online tutorial series.
  • http//radiopaedia.org/
  • A free educational radiology resource with one of
    the web's largest collections of radiology cases
    and reference articles.
  • http//www.radiologyassistant.nl/en/p42023a885587e
    /welcome-to-the-radiology-assistant.html

30
Websites Continued
  • http//learningradiology.com/index.htm
  • Seems to have some good stuff but difficult to
    navigate the site.
  • http//www.swansea-radiology.co.uk/index.html
  • http//bubbasoft.org/
  • Strange name but the website is useful. Breaks it
    into radiologic anatomy (identification of
    structures) and clinical radiology
    (identification of pathology).

31
Websites continued
  • http//eradiology.bidmc.harvard.edu/index.html
  • This source seems really valuable. Includes
    sections on primary care radiology,
    representative images of classic cases,
    interactive tutorials, and living anatomy
  • http//www.radiologyeducation.com/
  • List of radiology resources
  • http//www.med.wayne.edu/diagRadiology/TeachingFil
    e.html
  • Collection of interesting cases

32
Websites continued
  • http//headneckbrainspine.com/
  • Neuroradiology anatomy and cases.
  • https//3s.acr.org/CIP/Default.aspx
  • Case in point. American College of Radiologys
    case of the day.
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