"A brief but handy reference...the back cover's flap makes identification of the numbered anatomy easy...The arrangement of the sonograms with a corresponding line drawing makes it a very useful anatomical reference...a good addition to the basic reference library for beginning sonographers...a useful book for a beginner as a means to learn basic sonography."--ADVANCE for Imaging and Radiation Therapy
"Oriented for use as a workbook and self-study manual."--Book News
"Will certainly have..success in the USA. The manual, which..is quite inexpensive, represents the desire by the publisher to offer an easy-to-obtain didactic "workbook" on general ultrasonography directed to the students of sonography and to the young physicians interested in the roles of ultrasonography. The text is very clear, with informative drawings, and there is a good number of scoring boards reporting the normal values of the different measurements, in particular dealing with the pregnancy status. The iconography is of good quality.."--Clinical Imaging
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| 2-1: Regarding Wilm's tumor, please answer with TRUE or FALSE. |
| a. | T or F | Associated with with inherited aniridia. |
| b. | T or F | Associated with Beckwith-Weidemann. |
| c. | T or F | Invades the IVC. |
| d. | T or F | Most common pediatric renal/perinephric tumor to encase vessels. |
| 2-2: Regarding malacoplakia: Please answer with TRUE or FALSE. |
| a. | T or F | Premalignant. |
| b. | T or F | Associated with E.coli infection. |
| c. | T or F | More common in females. |
| d. | T or F | Most commonly occurs in the bladder. |
| e. | T or F | Michaelis-Gutmann bodies on biopsy are a definitive diagnostic finding. |
| f. | T or F | Predisposition in diabetics.. |
| 2-3: What is the MOST COMMON cause of lateral deviation of the ureters? |
| A | Lymphoma |
| B | Retroperitoneal fibrosis |
| C | Aneurysm |
| D | Lipomatosis |
| 1-1: A corpus luteum cyst usually resolves by what gestational age? Pick ONE answer. |
| A | 5 wks |
| B | 10 wks |
| C | 15 wks |
| D | 18 wks |
| 1-2: Which ONE of the following testicular neoplasms is not of germ cell origin? |
| A | Seminoma |
| B | Leydig cell tumor |
| C | Choriocarcinoma |
| D | Embryonal cell carcinoma |
| E | Teratoma |
| 1-3: Scenario: A 30 year old male with enlarged testicle. Ultrasound reveals a hypoechoic intratesticular mass. Please answer EACH of the following with TRUE or FALSE. |
| a. | T or F | Ultrasound can distinguish benign from malignant. |
| b. | T or F | Intratesticular location (vs extratesticular location such as epididymis) suggests malignancy. |
| c. | T or F | Elevated b-HCG and AFP suggest metastatic disease. |
| d. | T or F | Earliest metastases are to the iliac chain. |
| 1-4: What is the most likely cause of penile strictures and filling of Littre's glands in a patient with symptoms of forced stream. Choose the BEST answer. |
| A | Prior gonococcal infection. |
| B | Prior instrumentation |
| C | Saddle injury answers: 1- d 2- b 3- b 4- a |
Regarding CT of brain:
CSF has a lower attenuation than brain
the fourth ventricle is triangular in section
sections are taken at 30% to the orbitomeatal line
basilar artery can be seen on unenhanced scans
Regarding hazards of MRI:
radiofrequency pulses can cause electric currents in the patients
MRI is useful in dectecting intraocular foreign bodies
pregnancy is a relative contraindication
unchelated gadolinium is safe
the major cause of damage by RF pulse is thermal injury
In CT:
filtered back projection is commonly used in modern scanners
a window level of 200 is useful for bone imaging
dose is linearly related to number of contiguous slices
the efficiency of a gas detector is better than that of a scintillation detector
In Magnetic Resonance Imaging:
signals come only from excess nuclei in one direction
paired protons have zero spin angular momentum
Larmor frequency is the frequency of pulsed magnetic weld
precession occurs when the magnetic vector of nuclei is parallel to the external magnetic field
nuclei with an even number of protons and neutrons can be used
In Magnetic Resonance Imaging:
flow of blood can cause a loss of signal
fat can be suppressed by STIR sequence
all hydrogen nuclei in a tissue have the same Larmor frequency
Larmor frequency is inversely proportional to the gyromagnetic ratio
Larmor frequency of the same nuclei is proportional to the external magnetic field
In CT scanning:
photomultiplier tubes are generally used as detectors
only the detectors rotate in 4th generation machines
data manipulation generally uses a Fast Fourier transform
the spatial resolution is limited by the number of pixels
image noise is reduced by using a faster scan-time
In magnetic Resonance Imaging (MRI):
the image is reconstructed from radio signals emitted by precession of atomic particles in a magnetic field
hydrogen is the element most suitable for MRI in man
magnetic field strengths up to 0.1 Tesla are generally required
superconducting electromagnets cooled by liquid Helium are often used
proton density imaging gives good soft tissue discrimination
is directly related to the strength of the applied magnetic field
is inversely related to be gyromagnetic ratio
is the same for all hydrogen nuclei in a tissue
is the same as the frequency of the radiofrequency pulse
MRI:
pregnancy is an absolute contraindication
the radiofrequency pulse may induce electric currents in the patient
the radiofrequency pulse may cause heating of the patient
the T1 of fat is shorter than that of water
is the investigation of choice in suspected intraocular foreign body
In CT
the spatial resolution is improved with a larger pixel size
most interactions are due to the photoelectric effect
each detector has its own collimator
scintillation detectors are less efficient than ionization detectors
MRI:
flowing blood gives signal void on T2 TSE sequence
pregnancy in the first trimester is a relative contraindication
gadolinium decreases T1 and T2 of appropriate tissues
gadolinium is safe in the unchelated form
gadolinium is a superparamagnetic substance
Modern CT Scanner:
uses several X-ray tubes to acquire data from different directions
uses several hundred detectors
produces images x resolution of 5 Lp/mm
produces images x min detectable contrast <>
can be considered low dose equipment
Concerning the CT image:
noise is independent of dose
is made up of pixels
resolution is equal to pixel size
will have less artifacts from partial vol. effect if x slice thickness
Can x partial vol. if x mA
In CT image, noise:
depends upon scan time
depends upon mA
will be greater when x slice thickness
will affect spatial resolution
will make low contrast objects difficult to detect
Contrast of CT image controlled by:
kV setting
mAs setting
type of detectors
window width
window level
MRI – acquisition time decreased by:
decreasing slice thickness
using short TR
using short TE
increasing the number of excitations
use of pre-saturation bands
CT:
5mm copper filters used
photoelectric effect is main one in CT
Hounsfield no. of fat is about –100
pixel = Representation of linear attenuation coefficient of voxel
use of narrow windows gives higher contrast
MRI:
CSF has a low signal on T1
CSF is brighter than grey matter on T2
white matter is brighter than grey matter on T1
longitudinal relaxation is always longer for all tissues than transversal relaxation
use of mascara causes artefact
MRI:
useful in evaluation of intra ocular foreign bodies:
Faraday (age encloses the fringe field)
pregnancy is a relative contra indication (1st trimester)
radio Frequency pulse – causes local heating
RF pulse – causes electrical currents in the body
fields above 2T should not be used
produces images of proton density
measures spin-lattice relaxation
requires radio-frequency pulse to induce the signal
requires a field gradient for spatial coding
MRI Policies - Safety and Contraindications
Metallic fragments, clips or devices in the brain, eye, spinal canal, etc.:
Movement in the bore of the magnet may damage sensitive tissues. Plain radiography is sufficient for screening. Some intracranial clips may be safe, but these must have been tested in the OR just prior to implantation.
Magnetically activated implanted devices:
Cardiac pacemakers, insulin pumps, neurostimulators, cochlear implants, etc. may be de-programmed.
Non-graphite spinal cord tongs: Graphite tongs are compatible.
Thermodilution Swan-Ganz catheter: Local heating can result.
Metal outside the brain and eye is Not a contraindication: Magnetic deflection is minimal compared to normal physiologic forces. Cardiac valves), inferior vena cava filters, IUD's and metallic prostheses are safe, unless there is doubt as to positional stability.
Decreased renal function is Not a contraindication: Gadolinium contrast agents are not nephrotoxic at does used as per our protocols, although excretion is primarily renal.
Signed consent is not needed unless a patient is identified as high risk for gadolinium.
Risk of nephrogenic systemic fibrosis (NSF) in patients with severe renal failure (stage 4 or 5; GFR <>:
1. Benefit/risk and indication for gadolinium contrast agent should be reevaluated by a radiologist.
2. If unenhanced MRI is likely to provide sufficient information, gadolinium should not be administered to these patients.
3. If, after review of clinical indications, gadolinium enhancement is judged to be important for diagnosis, the lowest effective dose of contrast agent should be used. MultiHance (gadobenate dimeglumine) is preferred for these patients, since it allows a comparable effect to be obtained at lower gadolinium dose (see below). NSF case material thus far suggests that MRI using 20 ml or less of Magnevist or MultiHance poses negligible risk of NSF. Most NSF has occurred using more than 30 mL of gadolinium contrast agent, and most have been following Omniscan (gadodiamide).
4. For patients treated with hemodialysis, a hemodialysis session within a few hours following gadolinium contrast injection is likely to further reduce NSF risk.
----------------------------------------------------------------------------------------------------
Standard Gadolinium doses:
Magnevist
standard dose: 0.1 mmol/kg
single station Body MRA: 0.15 mmol/kg
MRV or bolus chase MRA: 0.2 mmol/kg
MultiHance
standard dose: 0.07 mmol/kg
FNH characterization, MRA, MRV: 0.1 mmol/kg
----------------------------------------------------------------------------------------------------
Steroid pretreatment policy: There is no routine pretreatment of patients with prior reaction to either iodinated or gadolinium contrast agents, since there has been no evidence that this is beneficial. Decisions to pretreat, or not to use contrast agent, may be made on an individual basis. If a prep is administered, it is identical to the prep for iodinated contrast: Medrol 32 mg po (or its equivalent) 12 and 2 hours prior to contrast administration.
MRI is not contraindicated, but... Prudence is urged, although there is no evidence that MRI is harmful to the fetus during any trimester.
Documented benefit. The risk is minimal at most, but the benefit must be finite. Ask: "Would CT be performed if MRI were not available." If "No", MRI should not be performed.
Only essential sequences should be performed.
Informed consent. Verbal and signed consent should be obtained, and the referring physician must be informed that bioeffects cannot be excluded with certainty. The dictation should mention the informed consent.
Pregnant women who are not being scanned should not enter the magnet room to accompany the patient. The benefit/risk ratio of the medical indication covers the patient, not friends or family.
Do not use gadolinium unless essential for diagnosis and management. Although there is no documented harm, it is known that gadolinium crosses the placenta into the amniotic fluid and is then swallowed and urinated back into the amniotic fluid. It's stability during this path, and the half life in the fetus, have not been determined.
Ultrasound as used in diagnostic radiology: f?fft
is an electromagnetic radiation with a frequency of 1-15 MHz
has a wavelength of 0.1 – 1.5mm in soft tissue
is attenuated exponentially
is heavily absorbed in air
is reflected at tissue interfaces with different acoustic impedances
The absorption of ultrasound: tff
occurs as a result of longitudinal relaxation processes
is due to scattering
is primarily dependant on resonance coupling
Concerning Ultrasound
the velocity in water is twice that in muscle
for the same incident angle the refracted angle is greater at a soft tissue/bone interface than at a soft tissue/fluid interface.
the velocity is dependent on temperature
impedance is inversely proportional to density
In the following statements concerning diagnostic ultrasound, ‘soft tissue’ excludes gas, cartilage and bone:
the attenuation coefficient of ultrasound in typical soft tissue when expressed in units of dB cm–1, is approximately proportional to frequency
the attenuation coefficient at a given frequency is the same in all soft tissues to within 10%
the speed of sound in most soft tissue is within 5% of 1540 ms–1 independent of frequency
the fraction of intensity reflected by a plane wave of ultrasound at normal incidence to a flat interface between typical soft tissues is usually less than 1%
a decrease in intensity by a factor of 2000 is equivalent to a change of –33 dB (to the nearest dB)
The function of a swept gain amplifier in an ultrasound scanner is:
to increase the gain of the transmitter for improved penetration
to reduce high frequency noise in the received signal
to compensate for signal attenuation of deeper echoes
to increase the receivers signal band-width
to steer electronically the transmitted beam
Ultrasound used for diagnostic purposes:
has a wave length in tissue of the order of 1mm
is generated by a sodium iodide crystal transducer
has a mean intensity of the order of 10 watt per cm2
is readily transmitted from tissue to air
Ultrasound of the breast:
requires a 3.5 MHz transducer
is a sensitive indicator of microcalcification
can accurately distinguish cystic and solid lesions
is of no value in the young dense breast
typically demonstrates acoustic enhancement behind the nipple
In ultrasound
ultrasound is produced by applying a magnetic field to a piezoelectric crystal
velocity and frequency are constant regardless of wavelength
with a curved transducer, focal length will decrease with curvature
resolution is better in central axis of the beam
spatial resolution is improved with a shorter pulse width
Ultrasound used in diagnostic imaging
is a longitudinal pressure wave
will not travel through a vacuum
has a velocity of the order of15m/s in water
can be deflected by a magnetic field
attenuation is measured in decibels (dB)
The resolution of an ultrasound scanner
is improved along the beam axis by increasing the ultrasound pulse height
is improved laterally by increasing the pulse repetition frequency
is dependent laterally on the beam width
with a mechanical is symmetrical in all axes
improves as the ultrasound frequency is increased
A pulse of ultrasound from a medical transducer
has a velocity that is inversely proportional to the media density
propagates with a transverse wave motion
has a band width that is inversely proportional to pulse length
has the lower frequencies within its spectrum preferentially absorbed by the media
is diffracted by small targets of similar dimensions to the beam
concerning diagnostic ultrasound
modern piezoelectric crystals are quartz compounds
a piezoelectric with a high Q factor makes a good receiver of echoes
the diameter of the crystal determines the resonant frequency
increasing the frequency increases the absorption of the sound
the absorption coefficient for fat is higher than that of water
In the display of an ultrasound image
A-mode utilises a moving time base
B-mode produces an image of a section or slice through the patient
returning echoes can be displayed either as white or black dots
a digital scan converter uses binary code storage
the time gain compensation graph is linear
Concerning the effects of ultrasound
heat results from the interaction of ultrasound and tissue
'cavitation' occurs in the lungs
the intensity of the sound is unrelated to the chance of biological effects
medical ultrasound is safe
it does not cause ionisation
In grey-scale, real-time ultrasound
returning echoes are assigned a shade of grey according to their intensity
at least 16 frames/second are needed for a flicker-free display
image resolution is increased when frame rate is increased
an increase in the number of lines per field of view requires a decrease in the frame frequency
decreasing the angle of a sector scan has no effect on image resolution
Ultrasound:
is electromagnetic radiation
can be focused to a certain extent
at soft tissue to soft tissue interface about 3% is reflected
at soft tissue to bone interface about 40% is reflected
is safe at diagnostic energies
Ultrasound:
is sound above 20 kHz (cycles per second)
1 MHz has wavelength of 1.5mm
the higher the frequency the better the resolution, hence use of 15–19 MHz in ophthalmic work
the higher the frequency the greater the penetration
lateral resolution of ultrasound is about 2cm
linear resolution of ultrasound is about 0.1mm
linear and lateral resolutions of X-ray film are less than 0.5mm
Ultrasound:
may be detected by a piezoelectric crystal
voltage changes across the crystal cause expansion and contraction resulting in pressure waves
the same crystal cannot be used for producing as well as receiving ultrasound
continuous sound is used to detect doppler effect
in pulsed ultrasound the pulse width is shorter than the listening interval
Ultrasound:
is used in short wave diathermy
produces heating of tissues
can be reflected
produces ionising radiation
produces blackening of a photographic emulsion
interfaces are not usually detected if less than 5% of the incident beam is reflected
substances of different densities have different acoustic impedances
Ultrasound in clinical medical practice:
is used in 1-15 MHz range
uses wavelengths of 0.15mm –1.5mm
is completely attenuated in air
the longer the wavelength the better the resolution
is refracted at an interface
an interface is most clearly shown when incident beam strikes it at right angles.
Ultrasound:
has a speed of 3000 m/s in soft tissue
changing acoustic impedance causes refraction
delay can be used to decrease amplitude of strong echoes behind fluid filled structures
time gain compensator is used to enhance echoes from deeper structures
A phase arrayed ultrasound scanner can vary:
direction of beam
focal length
axial resolution
lateral resolution
pulse repetition frequency
An ultrasound beam travelling through soft tissues:
has approximately the same velocity as in water
has a velocity of approximately 1500m per second
the amount (i.e. angle) of refraction at an interface depends on the ratio of the velocities of the two media
is attenuated at a rate of approximately 1 dB/MHz/cm
is usually in the frequency range 0.1 to 1 MHz for diagnostic purposes
Ultrasound reflected at the interface between two organs:
is optimum when the beam is incident at 90 degrees to the interface
relies on 5% of the beam reflected for adequate detection
requires the organs to remain stationary
there must be a density difference between the two organs
depends on the difference in the product of density and speed
Ultrasound:
causes heating of tissues as it is absorbed
slows down as it is absorbed
always travels in straight lines
Ultrasound:
piezoelectric material distorts when subjected to mag. field
piezoelectric material produce pot. difference when distorted
max. transmission from transducer when crystal backed x air
high q factor crystal will produce wide range of amplitudes
impedence = density x particle veloctiy
Use of a preprocessing curve:
x noise in a B scan
x gain of A scan
expand displayed dynamic range of certain tissues
match hardcopy input + scanner output dynamic range
enables faster scan conv.
Ultrasound:
velocity of sound in water is approx. 1500 meters/second
velocity of sound waves proportional to frequency
cannot detect sound if <5%>
get reflection with a difference in products of velocity and density
for reflection, tissues should have a density difference
The following statements are true concerning diagnostic ultrasound:
a 5MHz probe is suitable for examining the adult liver
the common bile duct can usually be demonstrated in normal subjects
the kidneys are best examined using a posterior approach
a linear scan motion demonstrates liver parenchyma more satisfactorily than a compound scan in motion
better results are usually obtained in obese patients than in thin patients
In medical use of ultrasound:
the diagnostic frequency range is 1 – 15MHz
ultrasound waves are poorly absorbed in soft tissues
ultrasound waves pass readily through air
reflection of ultrasound waves occurs by the piezoelectric effect
the Doppler principle is employed to detect movement of structures
Ultrasonics used in medical diagnosis:
has atypical wavelength in tissues of about 1mm
is completely harmless to living tissues
can be used to locate some soft tissue interfaces
is used in preference to some radiation because it is more penetrating
can be used to measure instantaneous blood velocity
The length of US pulses is kept to absolute minimum to:
improve lat resolution
improve axial resolution
decrease us intensity produced
scattering is reduced
scattering is improved
mri ct frcr 2a
Regarding CT of brain:
CSF has a lower attenuation than brain
the fourth ventricle is triangular in section
sections are taken at 30% to the orbitomeatal line
basilar artery can be seen on unenhanced scans
Regarding hazards of MRI:
radiofrequency pulses can cause electric currents in the patients
MRI is useful in dectecting intraocular foreign bodies
pregnancy is a relative contraindication
unchelated gadolinium is safe
the major cause of damage by RF pulse is thermal injury
In CT:
filtered back projection is commonly used in modern scanners
a window level of 200 is useful for bone imaging
dose is linearly related to number of contiguous slices
the efficiency of a gas detector is better than that of a scintillation detector
In Magnetic Resonance Imaging:
signals come only from excess nuclei in one direction
paired protons have zero spin angular momentum
Larmor frequency is the frequency of pulsed magnetic weld
precession occurs when the magnetic vector of nuclei is parallel to the external magnetic field
nuclei with an even number of protons and neutrons can be used
In Magnetic Resonance Imaging:
flow of blood can cause a loss of signal
fat can be suppressed by STIR sequence
all hydrogen nuclei in a tissue have the same Larmor frequency
Larmor frequency is inversely proportional to the gyromagnetic ratio
Larmor frequency of the same nuclei is proportional to the external magnetic field
In CT scanning:
photomultiplier tubes are generally used as detectors
only the detectors rotate in 4th generation machines
data manipulation generally uses a Fast Fourier transform
the spatial resolution is limited by the number of pixels
image noise is reduced by using a faster scan-time
In magnetic Resonance Imaging (MRI):
the image is reconstructed from radio signals emitted by precession of atomic particles in a magnetic field
hydrogen is the element most suitable for MRI in man
magnetic field strengths up to 0.1 Tesla are generally required
superconducting electromagnets cooled by liquid Helium are often used
proton density imaging gives good soft tissue discrimination
is directly related to the strength of the applied magnetic field
is inversely related to be gyromagnetic ratio
is the same for all hydrogen nuclei in a tissue
is the same as the frequency of the radiofrequency pulse
MRI:
pregnancy is an absolute contraindication
the radiofrequency pulse may induce electric currents in the patient
the radiofrequency pulse may cause heating of the patient
the T1 of fat is shorter than that of water
is the investigation of choice in suspected intraocular foreign body
In CT
the spatial resolution is improved with a larger pixel size
most interactions are due to the photoelectric effect
each detector has its own collimator
scintillation detectors are less efficient than ionization detectors
MRI:
flowing blood gives signal void on T2 TSE sequence
pregnancy in the first trimester is a relative contraindication
gadolinium decreases T1 and T2 of appropriate tissues
gadolinium is safe in the unchelated form
gadolinium is a superparamagnetic substance
Modern CT Scanner:
uses several X-ray tubes to acquire data from different directions
uses several hundred detectors
produces images x resolution of 5 Lp/mm
produces images x min detectable contrast <>
can be considered low dose equipment
Concerning the CT image:
noise is independent of dose
is made up of pixels
resolution is equal to pixel size
will have less artifacts from partial vol. effect if x slice thickness
Can x partial vol. if x mA
In CT image, noise:
depends upon scan time
depends upon mA
will be greater when x slice thickness
will affect spatial resolution
will make low contrast objects difficult to detect
Contrast of CT image controlled by:
kV setting
mAs setting
type of detectors
window width
window level
MRI – acquisition time decreased by:
decreasing slice thickness
using short TR
using short TE
increasing the number of excitations
use of pre-saturation bands
CT:
5mm copper filters used
photoelectric effect is main one in CT
Hounsfield no. of fat is about –100
pixel = Representation of linear attenuation coefficient of voxel
use of narrow windows gives higher contrast
MRI:
CSF has a low signal on T1
CSF is brighter than grey matter on T2
white matter is brighter than grey matter on T1
longitudinal relaxation is always longer for all tissues than transversal relaxation
use of mascara causes artefact
MRI:
useful in evaluation of intra ocular foreign bodies:
Faraday (age encloses the fringe field)
pregnancy is a relative contra indication (1st trimester)
radio Frequency pulse – causes local heating
RF pulse – causes electrical currents in the body
fields above 2T should not be used
produces images of proton density
measures spin-lattice relaxation
requires radio-frequency pulse to induce the signal
requires a field gradient for spatial coding
