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Imaging Studies
DR. HAILIN WU
DR. YOSEPH FELEKE
Imaging Studies
MRI
X-Ray
SPECT
CT
Ultrasound
Imaging Studies
Imaging Studies (X-Rays, Ultrasonography, Computed
Tomography (CT), Magnetic Resonance Imaging (MRI),
positron emission tomography (PET) scan, Endoscopy
(colonoscopy, cystoscopy, bronchoscopy), Angiography,
EKG, and electromyogram (EMG) )
Diagnostic Procedures (Cardiovascular, Respiratory, GI,
Urinary, musculoskeletal, Neurological disorders (Brain,
Spinal Cord and Nerve Disorders))
Diagnostic Images – X-rays
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X-rays are most appropriate to order for general bone-related concerns
and to evaluate the lungs and heart. Any patient c/o pain, especially
after trauma or with the presentation of deformities should be sent for
an x-ray.
Hairline fx will manifest as persistent pain with little to no swelling after
an injury.
The malfunction of what structure may result in dramatic bone loss,
leading to frequent, easy fractures and severe osteoporosis.
X-rays (pneumonia/fracture)
Ultrasound
It is used to visualize muscles, tendons, and many internal
organs, their size, structure and any pathological lesions
with real time tomographic images. They are also used to visualize a
fetus during routine and emergency prenatal care.
The technology is relatively inexpensive and portable, especially
when compared with modalities such as magnetic resonance
imaging(MRI) and computed tomography (CT).
It poses no known risks to the patient, it is generally described as a
"safe test" because it does not use ionizing radiation, which imposes
hazards (e.g. cancer production and chromosome breakage).
However, it has two potential physiological effects: it enhances
inflammatory response; and it can heat soft tissue.
Ultrasound biomedical Applications
heart and blood vessels, incl. the abdominal aorta and its major branches
liver
gallbladder
spleen
pancreas
kidneys
bladder
uterus, ovaries, and unborn child (fetus) in pregnant patients
eyes
thyroid and parathyroid glands
scrotum (testicles)
Liver cysts/fetus
Computed Tomography Scan (CT)
CT scans use a series of X-ray beams
It creates cross-sectional images, e.g. of the brain and shows the
structure of the brain, but not its function.
Digital geometry processing is used to generate a three-dimensional
image of the internals of an object from a large series of twodimensional X-ray images taken around a single axis of rotation
Cranial diagnosis of cerebrovascular accidents and
intracranial hemorrhage
CT generally does not exclude infarct in the acute stage of a stroke. For
detection of tumors, CT scanning with IV contrast is occasionally
used but is less sensitive than magnetic resonance imaging (MRI).
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Magnetic Resonance Imaging (MRI)
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An MRI is another non-invasive technique that uses a magnet to obtain
information about the body. The science of the MRI is based on how
hydrogen atoms behave in a magnetic field when disturbed by
radiofrequency signals.
The MRI is widely regarded as a superior diagnostic tool over the CT Scan,
though not as effective in evaluating the abdomen.
The characteristics of the MRI make it best for evaluations of the CNS,
bony structures, and joints. With contrast it can be useful in assessing
organs such as the liver and kidneys.
The greatest advantage of MRI is the absence of exposure to radiation,
which makes it the preferred choice for serial studies whenever
possible.
MRI
Positron Emission Tomography (PET)
A scanner detects radioactive material that is injected or
inhaled to produce an image of the brain.
Commonly used radioactively-labeled material includes
oxygen, fluorine, carbon and nitrogen.
When this material gets into the bloodstream, it goes to
areas of the brain that use it. So, oxygen and glucose
accumulate in brain areas that are metabolically active.
When the radioactive material breaks down, it gives off a
neutron and a positron.
When a positron hits an electron, both are destroyed and
two gamma rays are released.
Gamma ray detectors record the brain area where the
gamma rays are emitted. This method provides a
functional view of the brain.
Tomography
Heart Imaging
Brain Imaging
Heart
Kidney/Renal Imaging
Brain
Bone Scans
A set of
bone scan
projections
Kidney/Renal
Endoscopy (Colonoscopy)
Colonoscopy is performed by passing a flexible colonoscope through the
anal canal into the rectum and colon. The cecum is reached in >95% of
cases, and the terminal ileum can often be examined. Colonoscopy is
the "gold standard" for diagnosis of colonic mucosal disease.
Conscious sedation is usually given before colonoscopy in the United
States, although a willing patient and a skilled examiner can complete the
procedure without sedation in many cases.
Pedunculated colon polyp/Colon adenocarcinoma
Angiography
Angiography:
A rapid series of films obtained after a bolus contrast injection through a percutaneous
catheter. Imaging of aorta, major arteries and branches, tumors, and venous drainage
with late "run-off" films. Helical CT scans also generate angiographic images.
Digital subtraction angiography (DSA). Allows reverse negative views and requires
less contrast load
Cardiac angiography. Definitive for diagnosis and assessment of severity of CAD.
Significant (> 70% occlusion) stenotic lesions can be seen: 30% involve single vessels,
30% involve two, and 40% involve three vessels.
Cerebral angiography. Evaluation of intra- and extracranial vascular disease,
atherosclerosis, aneurysms, and A–V malformations. Not used for detection of cerebral
structural lesions (use MRI or CT instead)
Pulmonary angiography. Visualization of emboli, intrinsic or extrinsic vascular
abnormalities, A–V malformations, and bleeding due to tumors. Most accurate
diagnostic procedure for PE but only used if findings on helical CT or lung / scan are not
diagnostic
Bronchial angiography. Visualization of bleeding vessels from the systemic circuit.
Evaluation of hemoptysis in cases of known bronchiectasis
CT Angiography - Head
Circle of Willis/Vascular Malformations/ Aneurysms
Electrocardiography(EKG)
Electrocardiography (EKG) is the recording of the electrical activity of the heart.
Traditionally this is in the form of a transthoracic (across the thorax or chest)
interpretation of the electrical activity of the heart over a period of time, as detected
by electrodes attached to the surface of the skin and recorded or displayed by a device
external to the body.
Elements of the ECG:
P wave
Depolarization of both atria;
Relationship between P and QRS helps distinguish various cardiac arrhythmias
PR interval:
From onset of P wave to onset of QRS
Represents atria to ventricular conduction time (through His bundle)
Prolonged PR interval may indicate a 1st degree heart block
QRS complex:
Represents ventricular depolarization
Larger than P wave because of greater muscle mass of ventricles
ST segment:
Connects the QRS complex and T wave
QT Interval
Measured from beginning of QRS to the end of the T wave
QT interval varies based on heart rate
Electrocardiography(EKG)
Electromyogram (EMG)
Electromyography (EMG) is a diagnostic procedure to assess the health of muscles
and the nerve cells that control them (motor neurons).
Motor neurons transmit electrical signals that cause muscles to contract. An EMG
translates these signals into graphs, sounds or numerical values that a specialist
interprets.
An EMG uses tiny devices called electrodes to transmit or detect electrical signals.
During a needle EMG, a needle electrode inserted directly into a muscle records
the electrical activity in that muscle.
A nerve conduction study, another part of an EMG, uses electrodes taped to the
skin (surface electrodes) to measure the speed and strength of signals traveling
between two or more points.
EMG results can reveal nerve dysfunction, muscle dysfunction or problems with
nerve-to-muscle signal transmission.
Electromyogram (EMG)
AIDS
 AIDS (HIV, ELISA, Western Blot, CD4 Count,
CD4/CD8)
AIDS
The human immunodeficiency virus (HIV) is a lentivirus (a
subgroup of retrovirus) that causes the acquired immunodeficiency
syndrome (AIDS), a condition in humans in which progressive failure
of the immune system allows life-threatening opportunistic
infections and cancers to thrive. Virus infects and destroys CD4 +T
cells, and macrophage.
Specific tests for HIV include antibody and antigen detection.
Virus infects and destroys CD4+ T cell, macrophage
Diagnosis: Elisa, Western Blot.
CD4:8=1:2
AIDS