Keywords:
Continous Wave
Pulsed Ultrasound
Pulse Repitition Frequency
Pulse Repitition Period
Duty Factor
Spatial Pulse Length
Bandwidth
Fractional Bandwidth
Quality factor
Continuous wave (CW) is described where cycles are being repeated indefinitely thereby defined as a single frequency. On the other hand, pulsed wave or pulsed ultrasound (PW) is described as an ultrasound pulse of a few cycles seperated by gaps in time. The Pulse Repitition Frequency (PRF) is the number of pulses occuring in one second, and the units are in kilohertz (kHz). The Pulse Repition Period is the time measured from the beginning of one pulse to the beginning of the next, and is reciprocal to PRF. The Pulse Duration (PD) is the time it takes for one pulse to occur, and is proportional or equal to the period times the number of pulses or cycles in the pulse (n). The Pulse Duration (PD) is also reciprocal to the frequency, that is, if the frequency increases, then PD decreases thus a shorter pulse is produced. Shorter pulses are necessary to improve the quality of sonographic images.
In CW, the ultrasound is on 100% all the time, whereas in PW, the ultrasound is not on all the time. The time it takes for ultrasound to be on depends upon the Duty Factor (DF), which is the "fraction" of time that pulsed ultrasound is on. In other words, DF represents the amount of time that the sound is on. The Duty Factor (DF) is proportional to PRF and PD and reciprocal to PRP; that is, as PRF increases then DF increases and PRP decreases. In relation to frequency, the acutal number of cycles in PW depends upon DF as well. For example, a 5-MHz frequency CW ultrasound has 5-million cycles occuring per second, whereas in a 5-MHz frequency PW ultrasound has 50,000 cycles occuring per second or 50kHz. This is due to DF being only 1.0%, which makes the ultrasound being on only one hundreth of the time.
A pulse can be measured by acquiring the Spatial Pulse Length, which is the length of the pulse from front to back. The Spatial Pulse Length is proportional to the number of cycles in a pulse and the wavelength of the pulse. Units for SPL are in millimeters. Since wavelength increases with decreasing frequency, SPL increases with decreasing frequency. Therefore, if frequency increases then SPL and wavelength decreases and a shorter pulse is produced, which improves sonographic image resolution.
As frequency increases, shorter pulses are generated, which will increase the bandwith (more broader) and decrease the wavelength as well as SPL. In other words, the shorter the pulse (the fewer number of cycles), the more frequencies present in it (broader bandwidth). Bandwidth is defined as the range of frequencies contained in a pulse. Therefore, shorter pulses have broader bandwidths and fractional bandwidths, which is the bandwidth divided by the operating frequency and is reciprocal to the Quality factor (Q). In this case, Q would be low and thus signify a shorter pulse with a broad bandwidth at higher frequencies.
Sunday, December 20, 2009
Friday, December 18, 2009
Physics 101: The Basics
Keywords:
Medium
Acoustic Variables
Pressure
Density
Compression
Rarefaction
Propagation Speed
Stiffness
Longitudinal
Mechanical
Frequency
Infrasound
Ultrasound
Wavelength (Lambda)
Period
Sound is described as a wave that propagates through a medium (i.e air) associated with acoustic (hearing) variables. These acoustic variables are the following: Pressure, Density, Compression, Rarefaction, Temperature, and Particle motion. Without a medium, sound cannot travel (as in a vaccum). Gas, liquids, solids, and soft tissues are the types of mediums that sound can travel with differences of propagation speeds. Essentially, the medium determines the Propagation speed, and the Propagation speed, denoted as c (mm/microsecond), depends upon the stiffness of the material. In other words, the stiffer the material (more incompressible), the higher the propagation speed. Therefore, bone has the highest propagation speed, whereas gas or air has the lowest. In soft tissue, the propagation speed is "constant" and is calculated to be at 1.54mm/microsecond (1540 m/s). With that in mind, whenever the frequency changes (thus wavelength changes), the speed remains unchanged.
As sound travels through a medium, pressure and density go through cycles (frequency) of increase and decrease, and particles of the medium oscillate back and forth. As a result, sound waves can be broken down into two types: longitidunal and mechanical (or transverse). In longitudinal, the sound oscillate back and forth in the same direction of the linear plane or wave travel. In mechanical, sound inceases and decreases becoming perpendicular to the linear plane (90 degree angle). Therefore,sound is a wave of pressure and density variations with particle vibrations and is broken down into longitidinal and mechanical that describe the frequency or wave cycle.
Frequency is defined as the number of cycles in one second. A single cycle consists of high and low pressure associated with density. Pressure is proportional to density, that is, as pressure increases, density increases as well (and vice versa). Density is defined as mass/volume, and should not be confused being proportional to "intensity". Regions of high pressure and density are called compressions, whereas regions of low pressure and density are called rarefactions. Therefore, frequency can also be defined as the number of compressions and rarefactions in one second.
The different types of frequencies are the following: Hz, kHz (1000), and MHz(1,000,000). When comparing infrasound to ultrasound, the range goes from 20Hz to 20,000Hz (20kHz). Infrasound is below 20Hz, whereas ultrasound is greater than 20,000MHz (20kHz). The frequency depends upon the transducer and is reciprocal to the wavelength and period or time. In other words, as the frequency increases, the wavelength and period decreases. Wavelength is defined as the length of space over which one cycle occurs (front to back) and is proportional to the period or time. The period is the time it takes for one cycle to occur. Therefore, as the wavelength or lambda increases, then the period or time increases as well.
Medium
Acoustic Variables
Pressure
Density
Compression
Rarefaction
Propagation Speed
Stiffness
Longitudinal
Mechanical
Frequency
Infrasound
Ultrasound
Wavelength (Lambda)
Period
Sound is described as a wave that propagates through a medium (i.e air) associated with acoustic (hearing) variables. These acoustic variables are the following: Pressure, Density, Compression, Rarefaction, Temperature, and Particle motion. Without a medium, sound cannot travel (as in a vaccum). Gas, liquids, solids, and soft tissues are the types of mediums that sound can travel with differences of propagation speeds. Essentially, the medium determines the Propagation speed, and the Propagation speed, denoted as c (mm/microsecond), depends upon the stiffness of the material. In other words, the stiffer the material (more incompressible), the higher the propagation speed. Therefore, bone has the highest propagation speed, whereas gas or air has the lowest. In soft tissue, the propagation speed is "constant" and is calculated to be at 1.54mm/microsecond (1540 m/s). With that in mind, whenever the frequency changes (thus wavelength changes), the speed remains unchanged.
As sound travels through a medium, pressure and density go through cycles (frequency) of increase and decrease, and particles of the medium oscillate back and forth. As a result, sound waves can be broken down into two types: longitidunal and mechanical (or transverse). In longitudinal, the sound oscillate back and forth in the same direction of the linear plane or wave travel. In mechanical, sound inceases and decreases becoming perpendicular to the linear plane (90 degree angle). Therefore,sound is a wave of pressure and density variations with particle vibrations and is broken down into longitidinal and mechanical that describe the frequency or wave cycle.
Frequency is defined as the number of cycles in one second. A single cycle consists of high and low pressure associated with density. Pressure is proportional to density, that is, as pressure increases, density increases as well (and vice versa). Density is defined as mass/volume, and should not be confused being proportional to "intensity". Regions of high pressure and density are called compressions, whereas regions of low pressure and density are called rarefactions. Therefore, frequency can also be defined as the number of compressions and rarefactions in one second.
The different types of frequencies are the following: Hz, kHz (1000), and MHz(1,000,000). When comparing infrasound to ultrasound, the range goes from 20Hz to 20,000Hz (20kHz). Infrasound is below 20Hz, whereas ultrasound is greater than 20,000MHz (20kHz). The frequency depends upon the transducer and is reciprocal to the wavelength and period or time. In other words, as the frequency increases, the wavelength and period decreases. Wavelength is defined as the length of space over which one cycle occurs (front to back) and is proportional to the period or time. The period is the time it takes for one cycle to occur. Therefore, as the wavelength or lambda increases, then the period or time increases as well.
Monday, December 14, 2009
Holoprosencephaly (HPE)
What is Holoprosencephaly?
Holoprosencephaly (HPE) is a birth defect that occurs during the first few weeks of intrauterine life. HPE is a disorder in which the fetal brain does not grow forward and divide as it is supposed to during early pregnancy (incomplete cleavage of the embryonic forebrain/failure of the prosencephalon to cleave into the cerebral and lateral hemispheres).
This brain malformation can range from mild to severe and is classified into four types:
(1) Alobar (severe)--where the brain is not divided and there are severe abnormalities (there is an absence of the interhemispheric fissure, a single primitive ventricle, fused thalami, and absent third ventricle, olfactory bulbs and tracts and optic tracts).
(2) Semi-Lobar (moderate)--where the brain is partially divided and there are some moderate abnormalities; where there are two hemispheres in the rear but not the front of the brain (there are partially separated cerebral hemispheres and a single ventricular cavity).
(3) Lobar (mild)--where the brain is divided and there are some mild abnormalities (there is a well developed interhemispheric fissure however there is some fusion of structures).
(4) Middle Interhemispheric Variant (MIHV) -- where the middle of the brain (posterior frontal and parietal lobes) are not well separated.
Children diagnosed with HPE may have a small head (microcephaly), excessive fluid in the brain (hydrocephalus), variable degrees of mental retardation, epilepsy, endocrine abnormalities, or abnormalities of other organ systems such as cardiac, skeletal, genitourinary, and gastrointestinal. Mildly affected children may exhibit few symptoms and may live a normal life.
Facial deformities are often present in many children diagnosed with HPE. Mild forms of facial abnormalities may include a flat single-nostril nose (cebocephaly), close set eyes (hypotelorism), cleft lip and/or palate, or just one upper middle tooth (single maxillary central incisor). More severe facial deformities may include a single central eye (cyclopia), a nose located on the forehead (proboscis), or missing facial features.
What causes holoprosencephaly?
The cause of HPE is currently unknown. Often, no specific cause can be identified. Suggested risk factors include maternal diabetes, infections during pregnancy (syphilis, toxoplasmosis, rubella, herpes, cytomegalovirus), and various drugs taken during pregnancy (alcohol, aspirin, lithium, thorazine, anticonvulsants, hormones, retinoic acid). Women with previous pregnancy loss and first trimester bleeding are also more likely to have a child diagnosed with HPE.
Although many children with HPE have normal chromosomes, specific chromosomal abnormalities have been identified in some patients. There is evidence that in some families, HPE is inherited (autosomal dominant as well as autosomal or X-linked recessive inheritance).
Several genes have been identified that play a role in holoprosencephaly.
How common is this defect?
It is estimated that HPE affects between 1 in 5,000-10,000 live births. Since many pregnancies with a fetus diagnosed with HPE end in miscarriage, the frequency of HPE among all pregnancies may be as high as 1 in 200-250. Current studies indicate that only 3% of all fetuses with HPE survive to delivery and the vast majority of these infants do not survive past the first six months of life. The prognosis for a child diagnosed with HPE depends on the type of HPE and the presence of associated anomalies. The most severely affected children may live several months or years and the least affected may live a normal life span. Almost two-thirds of affected patients have alobar HPE and approximately one quarter are diagnosed with semilobar HPE.
Summary
HPE is characterized by a failure of transformation of the prosencephalon into cerebral hemispheres with separate lateral ventricles. HPE has many associated anomalies, both of the nervous system and face. HPE is also associated with malformations in other body systems, particularly when it has a chromosomal etiology. The true spectrum of HPE, its clinical manifestations, and underlying etiologies require further elucidation. Applying this knowledge to individuals and their families is of utmost importance.
References
Cohen (1989) Teratology 40:211-235
Cohen (1989) Am J of Med Genet 34:271-288
Cohen & Sulik (1992) J of Craniofacial Genet Dev Bio 12:196-244
DeMyer & Zeman (1963) Confin Neurol 23:1-36
DeMyer, Zeman, & Palmer (1964) Pediatrics 34: 256-263
Ming & Muenke (l998) Clin Genet 53:155-163
Plawner LL, et al. (2002) Neuroanatomy of Holoprosencephaly as Predictor of Function: Beyond the Face Predicting the Brain. Neurology, 59:1058-1066.
Lewis AJ, et al. (2002) Middle interhemispheric variant of holoprosencephaly: a distinct cliniconeuroradiologic subtype. Neurology (in press).
spotted at The Carter Centers for Brain Research
Holoprosencephaly (HPE) is a birth defect that occurs during the first few weeks of intrauterine life. HPE is a disorder in which the fetal brain does not grow forward and divide as it is supposed to during early pregnancy (incomplete cleavage of the embryonic forebrain/failure of the prosencephalon to cleave into the cerebral and lateral hemispheres).
This brain malformation can range from mild to severe and is classified into four types:
(1) Alobar (severe)--where the brain is not divided and there are severe abnormalities (there is an absence of the interhemispheric fissure, a single primitive ventricle, fused thalami, and absent third ventricle, olfactory bulbs and tracts and optic tracts).
(2) Semi-Lobar (moderate)--where the brain is partially divided and there are some moderate abnormalities; where there are two hemispheres in the rear but not the front of the brain (there are partially separated cerebral hemispheres and a single ventricular cavity).
(3) Lobar (mild)--where the brain is divided and there are some mild abnormalities (there is a well developed interhemispheric fissure however there is some fusion of structures).
(4) Middle Interhemispheric Variant (MIHV) -- where the middle of the brain (posterior frontal and parietal lobes) are not well separated.
Children diagnosed with HPE may have a small head (microcephaly), excessive fluid in the brain (hydrocephalus), variable degrees of mental retardation, epilepsy, endocrine abnormalities, or abnormalities of other organ systems such as cardiac, skeletal, genitourinary, and gastrointestinal. Mildly affected children may exhibit few symptoms and may live a normal life.
Facial deformities are often present in many children diagnosed with HPE. Mild forms of facial abnormalities may include a flat single-nostril nose (cebocephaly), close set eyes (hypotelorism), cleft lip and/or palate, or just one upper middle tooth (single maxillary central incisor). More severe facial deformities may include a single central eye (cyclopia), a nose located on the forehead (proboscis), or missing facial features.
What causes holoprosencephaly?
The cause of HPE is currently unknown. Often, no specific cause can be identified. Suggested risk factors include maternal diabetes, infections during pregnancy (syphilis, toxoplasmosis, rubella, herpes, cytomegalovirus), and various drugs taken during pregnancy (alcohol, aspirin, lithium, thorazine, anticonvulsants, hormones, retinoic acid). Women with previous pregnancy loss and first trimester bleeding are also more likely to have a child diagnosed with HPE.
Although many children with HPE have normal chromosomes, specific chromosomal abnormalities have been identified in some patients. There is evidence that in some families, HPE is inherited (autosomal dominant as well as autosomal or X-linked recessive inheritance).
Several genes have been identified that play a role in holoprosencephaly.
How common is this defect?
It is estimated that HPE affects between 1 in 5,000-10,000 live births. Since many pregnancies with a fetus diagnosed with HPE end in miscarriage, the frequency of HPE among all pregnancies may be as high as 1 in 200-250. Current studies indicate that only 3% of all fetuses with HPE survive to delivery and the vast majority of these infants do not survive past the first six months of life. The prognosis for a child diagnosed with HPE depends on the type of HPE and the presence of associated anomalies. The most severely affected children may live several months or years and the least affected may live a normal life span. Almost two-thirds of affected patients have alobar HPE and approximately one quarter are diagnosed with semilobar HPE.
Summary
HPE is characterized by a failure of transformation of the prosencephalon into cerebral hemispheres with separate lateral ventricles. HPE has many associated anomalies, both of the nervous system and face. HPE is also associated with malformations in other body systems, particularly when it has a chromosomal etiology. The true spectrum of HPE, its clinical manifestations, and underlying etiologies require further elucidation. Applying this knowledge to individuals and their families is of utmost importance.
References
Cohen (1989) Teratology 40:211-235
Cohen (1989) Am J of Med Genet 34:271-288
Cohen & Sulik (1992) J of Craniofacial Genet Dev Bio 12:196-244
DeMyer & Zeman (1963) Confin Neurol 23:1-36
DeMyer, Zeman, & Palmer (1964) Pediatrics 34: 256-263
Ming & Muenke (l998) Clin Genet 53:155-163
Plawner LL, et al. (2002) Neuroanatomy of Holoprosencephaly as Predictor of Function: Beyond the Face Predicting the Brain. Neurology, 59:1058-1066.
Lewis AJ, et al. (2002) Middle interhemispheric variant of holoprosencephaly: a distinct cliniconeuroradiologic subtype. Neurology (in press).
spotted at The Carter Centers for Brain Research
Sunday, December 13, 2009
Postmaturity
What is postmaturity?
The normal length of pregnancy is from 37 to 41 weeks. Postmaturity refers to any baby born after 42 weeks gestation or 294 days past the first day of the mother's last menstrual period. About 7 percent of all babies are born at 42 weeks or later. Other terms often used to describe these late births include post-term, postmaturity, prolonged pregnancy, and post-dates pregnancy.
What causes postmaturity?
It is not known why some pregnancies last longer than others. Postmaturity is more likely when a mother has had one or more previous post-term pregnancies. Sometimes a mother's pregnancy due date is miscalculated because she is not sure of her last menstrual period. A miscalculation may mean the baby is born earlier or later than expected.
Why is postmaturity a concern?
Postmature babies are born at the very end, or past, the normal length of pregnancy. The placenta, which supplies babies with the nutrients and oxygen from the mother's circulation, begins to age toward the end of pregnancy, and may not function as efficiently as before. Other concerns include the following:
•Amniotic fluid volume may decrease and the fetus may stop gaining weight or may even lose weight.
•Risks can increase during labor and birth for a fetus with poor oxygen supply.
•Problems may occur during birth if the baby is large.
•Postmature babies may be at risk for meconium aspiration, when a baby breathes in fluid containing the first stool.
•Hypoglycemia (low blood sugar) can also occur because the baby has too little glucose-producing stores.
What are the symptoms of postmaturity?
The following are the most common symptoms of postmaturity. However, each baby may show different symptoms of the condition. Symptoms may include:
•dry, peeling skin
•overgrown nails
•abundant scalp hair
•visible creases on palms and soles of feet
•minimal fat deposits
•green/brown/yellow coloring of skin from meconium staining (the first stool passed during pregnancy into the amniotic fluid)
Symptoms of postmaturity may resemble other conditions or medical problems. Always consult your baby's physician for a diagnosis.
How is postmaturity diagnosed?
Postmaturity is usually diagnosed by a combination of assessments, including the following:
•your baby's physical appearance
•length of the pregnancy
•your baby's assessed gestational age
Treatment of postmaturity:
Specific treatment for postmaturity will be determined by your baby's physician based on:
•your baby's gestational age, overall health, and medical history
•extent of the condition
•your baby's tolerance for specific medications, procedures, or therapies
•expectations for the course of the condition
•your opinion or preference
In a prolonged pregnancy, testing may be done to check fetal well-being and identify problems. Tests often include ultrasound, non-stress testing (how the fetal heart rate responds to fetal activity), and estimation of the amniotic fluid volume.
The decision to induce labor for post-term pregnancy depends on many factors. During labor, the fetal heart rate may be monitored with an electronic monitor to help identify changes in the heart rate due to low oxygenation. Changes in a baby's condition may require a cesarean delivery.
Special care of the postmature baby may include:
•checking for respiratory problems related to meconium (baby's first bowel movement) aspiration.
•blood tests for hypoglycemia (low blood sugar).
Prevention of postmaturity:
Accurate pregnancy due dates can help identify babies at risk for postmaturity. Ultrasound examinations early in pregnancy help establish more accurate dating by measurements taken of the fetus. Ultrasound is also important in evaluating the placenta for signs of aging.
Spotted at Lucille Packard Children's Hospital
Monday, December 7, 2009
Down Syndrome (Trisomy 21)
Down Syndrome, or Trisomy 21, is a congenital defect (mutation) caused by the presence of an extra chromosome 21 in all cells of the individual or fetus. Babies who are born with Down Syndrome have poor mental and physical development thus motor and social skills are delayed. The syndrome usually occurs in women over the age of 35 at a ratio of 1/365. As maternal age increases up to 45, the likelihood of the mother carrying a Down Syndrome fetus is 1/32. A Triple Screen test can be used to diagnose the baby with Down Syndrome, which measures three specific levels: AFP, hCG, and estriol. The invasive procedure is done through amnioscentesis or Chorionic Villus Sampling (CVS) in which amniotic fluid is drawn up from the mother to measure the levels of AFP, hCG, and estriol. If AFP levels are depressed, but hCG and estriol are elevated, there is an increased likelihood of a Down Syndrome fetus (however in Trisomy 18, all levels are depressed).
A specific marker for determining chromosomal abnormalities such as Down Syndrome is the Nuchal Translucency (NT) measurement. This measures the thickness in the back of the fetal neck during the 11-13 week scan. If the measurement is more than 3mm, then suspect Down Syndrome. Another marker that is associated with Down Syndrome is the Nuchal Fold (NF) measurement, which is measured in the back of the "fetal head". If the measurement is more than 6mm, then suspect a Down Syndrome fetus. Below is an image showing a normal NT measurement of 1.7mm in a late First Trimester fetus.
Other ultrasonic signs that are associated with Down Syndrome include the following:
Absence of nasal bone (from profile shot)
Cleft lip and palate (from facial shot)
Ventricularmegaly or Hydrocephalus (more than 10mm/1cm)
Low ear set
Cystic Hygroma
Cushion Defect (ASD)
VSD
Moderate Band (thick papillary muscle)
Esophageal Atresia (stenosis of gastroesophageal junction)
Duodenal Atresia (double bubble sign)
Echogenic Bowel
Hydronephrosis
Clinodactyly
Short femur and Humerus length (less than 0.91)
Sandal toe
Clubfoot
Below are videos explaining about Down Syndrome and its rise (listen up techs!)...
A specific marker for determining chromosomal abnormalities such as Down Syndrome is the Nuchal Translucency (NT) measurement. This measures the thickness in the back of the fetal neck during the 11-13 week scan. If the measurement is more than 3mm, then suspect Down Syndrome. Another marker that is associated with Down Syndrome is the Nuchal Fold (NF) measurement, which is measured in the back of the "fetal head". If the measurement is more than 6mm, then suspect a Down Syndrome fetus. Below is an image showing a normal NT measurement of 1.7mm in a late First Trimester fetus.
Other ultrasonic signs that are associated with Down Syndrome include the following:
Absence of nasal bone (from profile shot)
Cleft lip and palate (from facial shot)
Ventricularmegaly or Hydrocephalus (more than 10mm/1cm)
Low ear set
Cystic Hygroma
Cushion Defect (ASD)
VSD
Moderate Band (thick papillary muscle)
Esophageal Atresia (stenosis of gastroesophageal junction)
Duodenal Atresia (double bubble sign)
Echogenic Bowel
Hydronephrosis
Clinodactyly
Short femur and Humerus length (less than 0.91)
Sandal toe
Clubfoot
Below are videos explaining about Down Syndrome and its rise (listen up techs!)...
Thursday, December 3, 2009
11-13 Week Scan
Video lecture on first trimester screening that lasts for 45 minutes is a real good instructional tool for detecting pathologies. An internet course is also provided that covers all aspects of first trimester screening for chromosomal abnormalities (ie.Trisomy 21), the dignosis for major fetal defects, and screening for preeclampsia. The course, which is free of charge, is designed for techs to obtain the FMF certificate of competence which includes:
measurement of nuchal translucency
assessment of nasal bone
measurement of facial angle
assessment of ductus venous flow
assessment of tricuspid flow
measurement of uterine arter PI
After obtaining the competence, you are eligible to recieve a CME certificate.
If you want to look at the 11-13 week book, click here
For a preview of the 11-13 week scan video, click here
Video lecture spotted at fetalmedicine
measurement of nuchal translucency
assessment of nasal bone
measurement of facial angle
assessment of ductus venous flow
assessment of tricuspid flow
measurement of uterine arter PI
After obtaining the competence, you are eligible to recieve a CME certificate.
If you want to look at the 11-13 week book, click here
For a preview of the 11-13 week scan video, click here
Video lecture spotted at fetalmedicine
Ultrasound Screening of Abdominal Aorta
really good instructional video for scanning AO to detect the presence of Aortic Anureysm...a must see for vascular techs...
Careers in Vascular Ultrasound
now that's what i'm talking about...can't wait till i study vascular...LETS GO!
Wednesday, December 2, 2009
The Importance of Folic Acid
really good informational video explaining about the use of folic acid that can prevent "neural tube defects", like Spina Bifida, and should be taken before pregnancy...
News Update
"Targeted breast ultrasound can reduce biopsies for women under 40"
for all you female techs out there interested on Breast Ultrasound anomalies, then you may want to read this article. I'm more of a Vascular/Echo type of guy, but the article is intersting explaining that a targeted ultrasound of suspicious areas in the breast can be a "cost-effective alternative to invasive biopsies for women under 40". Think about it..
spotted at esciencenews
for all you female techs out there interested on Breast Ultrasound anomalies, then you may want to read this article. I'm more of a Vascular/Echo type of guy, but the article is intersting explaining that a targeted ultrasound of suspicious areas in the breast can be a "cost-effective alternative to invasive biopsies for women under 40". Think about it..
spotted at esciencenews
Monday, November 30, 2009
Spina Bifida (Myelomeningocele)
really nice video explaining about Spina Bifida and how it affects the baby...
Cleft Lip and Palate
central cleft lip Obtaining images of the fetal face during second trimester are essential to exclude cleft lip and palate. A gap in the upper lip and maxilla that appears anechoic in ultrasound is defined as cleft lip and palate. Cleft lip can be unilateral, bilateral, or central (paramedian). Central being the worst and unilateral being the most common, however, other sources claim that the malformation is usually paramedian. Below are two images of cleft upper lip and palate spotted at Radiographics.
For more images, click on the following links below
bilateral cleft lip and palate
bilateral cleft lip and palate2
bilateral cleft lip and palate3
shouts to Sonoworld
Thursday, November 19, 2009
Fetal Hydrops
Fetal Hydrops is when the uterus is too large for dates (large-for-date fetus) and is caused by the following features: fetal edema or skin thickness (macrosomia), polyhydraminous, ascites (liver, abdomen), pericardial effusion, pleural effusion, and abnormally large placenta. In ultrasound, the large placenta would appear homogenous and echogenic. This would occur during Rh incompatibility (mixing of maternal blood and fetal blood btw Rh- and Rh+).
When the mother has Rh- blood and the fetus has Rh+, the blood mixes together and this is termed immune hydrops. However, the mixing of Rh blood will not damage the fetus in the first pregnancy. During the second pregnancy, the anti-bodies produced in the first will attack the fetal red blood cells thereby harming the baby and is called erythroblastosis fetalis. In non-immune hydrops, the two of the six features of fetal hydrops previously mentioned are seen (ie. polyhydraminous, ascites).
When the mother has Rh- blood and the fetus has Rh+, the blood mixes together and this is termed immune hydrops. However, the mixing of Rh blood will not damage the fetus in the first pregnancy. During the second pregnancy, the anti-bodies produced in the first will attack the fetal red blood cells thereby harming the baby and is called erythroblastosis fetalis. In non-immune hydrops, the two of the six features of fetal hydrops previously mentioned are seen (ie. polyhydraminous, ascites).
Wednesday, November 18, 2009
Large For Dates
A large for date fetus is when the fetal weight is more than expected by being above the 90th percentile. A large fetus could be due to: polyhydraminous, large placenta (hydrops), macrosomia (skin thickening), or twin/multiple pregancies.
When a mother exhibits a twin pregancy test, automatically she is high risk OB. The most common reason for having twins is by either infertility treatment or genetic. Twins can be described by two types: identical and non-identical.
Identical twins (girl-girl) are monozygotic (one zygote) and have two membranes with the possibility of one chorionic membrane. Describing the membranes (chorionic, amniotic) can be broken down by the following:
1) Dichorionic, Diamniotic (before day 5)
2) Monochorionic, Diamniotic (btw day 5-9, most common)
3) Mochorionic, Monoamniotic (btw day 9-13)
4) Conjoined (after day 13)
Note that if Dichorionic and Diamniotic, then both membranes would have two placentas. However, if Monochorionic and Diamniotic, then one membrane (Mono) would have one placenta whereas the other (Di) would have two placentas. Another way to distinguish between Mono- and Di- is to look at the thickness of the membranes. Mono- will have a thin membrane (one) whereas Di- will have a thick membrane (two). Below are images describing the two membranes.
When a mother exhibits a twin pregancy test, automatically she is high risk OB. The most common reason for having twins is by either infertility treatment or genetic. Twins can be described by two types: identical and non-identical.
Identical twins (girl-girl) are monozygotic (one zygote) and have two membranes with the possibility of one chorionic membrane. Describing the membranes (chorionic, amniotic) can be broken down by the following:
1) Dichorionic, Diamniotic (before day 5)
2) Monochorionic, Diamniotic (btw day 5-9, most common)
3) Mochorionic, Monoamniotic (btw day 9-13)
4) Conjoined (after day 13)
Note that if Dichorionic and Diamniotic, then both membranes would have two placentas. However, if Monochorionic and Diamniotic, then one membrane (Mono) would have one placenta whereas the other (Di) would have two placentas. Another way to distinguish between Mono- and Di- is to look at the thickness of the membranes. Mono- will have a thin membrane (one) whereas Di- will have a thick membrane (two). Below are images describing the two membranes.
In non-identical twins (boy-girl), the membranes are "always" Dichorionic, Diamniotic (look at first picture). Non-identical twins are dizygotic (two zygotes). A good way to distinguish if both membranes are Di-Di is to look for "twin peak" sign, which is a traingular projection of placental tissue from the placental surface extending to the intertwin membrane. Below is an ultrasound image of the "twin peak" sign seen btw 10-14 wks GA.
Below are ultrasound images of twin pregnancies
9 Week Monochorionic, Diamniotic Twins
6 Week Dichorionic, Diamniotic Twins
Tuesday, November 17, 2009
PreTerm Birth (PTB)
PreTerm Birth (PTB) is caused by a weak cervix (or incompetent cervix) that creates changes to the internal cervical os by dilating or increasing the "funneling" angle and reducing cervical length (CL). As a result, the cervix may open early thus inducing a preterm delivery or miscarriage (spontaneous abortion). Essentially, more than 70% of premature babies are born between 34 and 36 wks (late preterm); 12% are born between 32 and 33 wks; and 10% are born between 28 and 31 wks.
In order to prevent this early labor from arising, a procedure known as a cervical "cerclage" is done to suture or stitch shut the cervix to prevent further dilation. The procedure can be done at about 12 to 14weeks before the cervix thins out, or as a emergency measure after the cervix has thinned (rarely done after 24 wks). However, the risks of cervical cerclage are rare but may include: infection, pPROM, cervical stenosis (d/t permanent narrowing or closure of the cervix), damage to the cervix during surgery, and excessive blood loss.
All premature babies are at risk for health problems, but the earlier a baby is born, the greater the risk for serious complications. For example, if a premature baby gets delivered before 32wks GA, the baby will appear small with organs less developed. Or if the baby is born at 36 wks GA but fetal weight is below the 10th percentile (weighing less than 2500 grams), then suspect Intrauterine Growth Restriction (IUGR) or "Small-for-Gestational Age"(SGA) fetus.
IUGR is a smaller than normal fetus caused by wrong LMP (blame mom),diminished amniotic fluid, pPROM, abnormal placenta, or fetal renal anomaly. The fetus is small because of insufficient nutrition due to alcohol/drug abuse, any chronic conditions (HRT Dz), does not eat well, or has had previous pregnancies in which there was poor fetal growth. IUGR has three types: asymmetric (seen late in 3rd Trimester), symmetric (seen early in pregnancy), and femur-sparing pattern.
In asymmetric IUGR, fetal trunk is small. In symmetric IUGR, entire fetus is smaller than normal, which also includes reduced sizes of internal organs (Nuchal thickening can also be assessed). In femur-sparing pattern IUGR, BPD is normal but AC and FL are low thus the brain and head is spared, but body or abdomen is considered small (usually not seen in late 3rd trimester).
In order to prevent this early labor from arising, a procedure known as a cervical "cerclage" is done to suture or stitch shut the cervix to prevent further dilation. The procedure can be done at about 12 to 14weeks before the cervix thins out, or as a emergency measure after the cervix has thinned (rarely done after 24 wks). However, the risks of cervical cerclage are rare but may include: infection, pPROM, cervical stenosis (d/t permanent narrowing or closure of the cervix), damage to the cervix during surgery, and excessive blood loss.
All premature babies are at risk for health problems, but the earlier a baby is born, the greater the risk for serious complications. For example, if a premature baby gets delivered before 32wks GA, the baby will appear small with organs less developed. Or if the baby is born at 36 wks GA but fetal weight is below the 10th percentile (weighing less than 2500 grams), then suspect Intrauterine Growth Restriction (IUGR) or "Small-for-Gestational Age"(SGA) fetus.
IUGR is a smaller than normal fetus caused by wrong LMP (blame mom),diminished amniotic fluid, pPROM, abnormal placenta, or fetal renal anomaly. The fetus is small because of insufficient nutrition due to alcohol/drug abuse, any chronic conditions (HRT Dz), does not eat well, or has had previous pregnancies in which there was poor fetal growth. IUGR has three types: asymmetric (seen late in 3rd Trimester), symmetric (seen early in pregnancy), and femur-sparing pattern.
In asymmetric IUGR, fetal trunk is small. In symmetric IUGR, entire fetus is smaller than normal, which also includes reduced sizes of internal organs (Nuchal thickening can also be assessed). In femur-sparing pattern IUGR, BPD is normal but AC and FL are low thus the brain and head is spared, but body or abdomen is considered small (usually not seen in late 3rd trimester).
Monday, November 16, 2009
News Update
"low birthweight babies at risk for delayed nuerological maturation"
i had to post...interesting article that mentioned about a research study conducted in Barcelona Spain, and found "small for gestational age" infants with normal placental function to be at risk for impaired nuerological development. That is, these babies may have a decrease in sensory (motor skills) and cognitive development that could affect their school as well as their adolescent period. To read the abstact on the Barcelona study, click here. To read the full article spotted on MedicalNewsToday, click on the links..
shouts to Sonoworld
i had to post...interesting article that mentioned about a research study conducted in Barcelona Spain, and found "small for gestational age" infants with normal placental function to be at risk for impaired nuerological development. That is, these babies may have a decrease in sensory (motor skills) and cognitive development that could affect their school as well as their adolescent period. To read the abstact on the Barcelona study, click here. To read the full article spotted on MedicalNewsToday, click on the links..
shouts to Sonoworld
Tuesday, November 10, 2009
Placenta II
Abruptio Placentae (Accidental Hemorrhage Abruption) is bleeding that occurs when the placenta seperates from the uterine wall. The bleed can be seen as anechoic fluid that may eventually form into a clot, which can exhibit low level echoes or internal debris within the area. Later on, the clot would appear echogenic in ultrasound image.
Abruptio placentae can occur at five different sites of the uterus: intraplacental or infarcts (within the placenta), subplacental/retroplacental (between myometrium and placenta), subchorionic/subamniotic (at edge of placenta--marginal bleed), intraamniotic (within amniotic cavity). Below is an image displaying an example of subplacental bleeding in ultrasound.
Causes of abruptio placentae may be difficult to determine but can be the following: rapid loss of amniotic fluid, trauma, or abnormally short umbilical cord (appear as three straight lines in US). Risk factors include: advanced maternal age, cigarette smoking, diabetes, high blood pressure, increased uterine distension (as seen with multiple pregnancies), abnormally large volume of amniotic fluid (polyhydraminous--most likely due to the fetus having trouble swallowing), or large number of prior deliveries. Symptoms include abdominal pain, back pain, and vaginal bleeding. Usually a C-Section is given if the internal bleeding is severe.
Monday, November 9, 2009
First Trimester Sonogram
6 Weeks
in this video you can actually see fetal pole and yolk sac...for another clip of the fetus at 6 weeks, click here
8 Weeks
9-13 Weeks
11 Weeks
Placenta I
The placenta serves as a function to exchange oxygen and carbon dioxide between mother and fetus. Usually maternal and fetal blood don't mix (only exception is till delivery), but if they do, supsect Rh pathology. The placenta also functions to work as defense mechanism to prevent viruses such as AIDS or Hep B&C to pass through the fetus (nicotine can also pass through as well). The placenta usually develops in the early second trimester (week 13), and becomes well established in week 15, which the retroplacental complex can be seen. In ultrasound, the placenta appears homogenous and echogenic. Later on, it becomes more heterogenous due to the development of calcifications and maternal lakes (veins and arteries).
The placenta is composed of three areas: basal layer, substance, and chorionic plate. The location can be anterior, posterior, fundal, or cervical, and must be determined in SAG. If found in the cervical region, in which the placenta has obstructed the whole area, then conisder in mind "placenta previa". The thickness of placenta should not exceed 4cm, and if thick then suspect hydatid form molar pregnancy (abnormal placental tissue implanted in UT).
The placenta can be broken down into stages or grades. Essentially, there are a total of 3 grades (0-3). As the placenta progresses through these grades, it becomes more echogenic and inactive. In Grade 0, the placenta has a smooth chorionic plate with no subtle or mild indentations. Grade 0 placenta is homogenous with no calcifications and is very active (necessary to promote gas exchange within the fetus). In Grade 1 placenta, the chorionic plate exhibits sublte indentations with punctuate calcifications. This normal placenta can be seen after 34 weeks. In Grade 2 placenta, the chorionic plate begins to have mild indentations with the development of comma-shaped calcifications within the placental substance. This normal placenta will appear more echogenic and can be seen after 36 weeks. Lastly, Grade 3 placenta will exhibit major indentations thereby dividing the placenta into segments. Linear calcifications can be seen within the substance and is normal after 38 weeks. For images on placental grading, click here.
The thing to keep in mind is that as the pregancy progresses, the placenta is able to move due to uterine size. As the fetus enlarges, so does the uterus thus affecting the position of the placenta. With that in mind, the placenta can move to the cervical area thereby obstructing the internal os. When this happens, this is termed "placenta previa".
There are different types of placenta previa: complete, partial, marginal, or low lying. Complete placenta previa is when the placenta has completely obstructed the internal cervical os. Partial placenta previa is when the placental tissue blocks only a portion of the internal cervical os. Marginal placental previa occurs when the substance extends up to but not above the internal cervical os (near proximal end of Cx). Low lying placenta, or potential placenta, is when the substance is 1cm away from internal cervical os. It is usually the low lying placenta that causes placental previa thereby inducing vascular malformation within the uterus. Another cause is abnormal uterine enlargement, which can cause the placenta to move towards the proximal end of the cervix. Below is video clip of placenta previa with the addition of abruptio placenta and the consequences that can happen with the condition.
The placenta is composed of three areas: basal layer, substance, and chorionic plate. The location can be anterior, posterior, fundal, or cervical, and must be determined in SAG. If found in the cervical region, in which the placenta has obstructed the whole area, then conisder in mind "placenta previa". The thickness of placenta should not exceed 4cm, and if thick then suspect hydatid form molar pregnancy (abnormal placental tissue implanted in UT).
The placenta can be broken down into stages or grades. Essentially, there are a total of 3 grades (0-3). As the placenta progresses through these grades, it becomes more echogenic and inactive. In Grade 0, the placenta has a smooth chorionic plate with no subtle or mild indentations. Grade 0 placenta is homogenous with no calcifications and is very active (necessary to promote gas exchange within the fetus). In Grade 1 placenta, the chorionic plate exhibits sublte indentations with punctuate calcifications. This normal placenta can be seen after 34 weeks. In Grade 2 placenta, the chorionic plate begins to have mild indentations with the development of comma-shaped calcifications within the placental substance. This normal placenta will appear more echogenic and can be seen after 36 weeks. Lastly, Grade 3 placenta will exhibit major indentations thereby dividing the placenta into segments. Linear calcifications can be seen within the substance and is normal after 38 weeks. For images on placental grading, click here.
The thing to keep in mind is that as the pregancy progresses, the placenta is able to move due to uterine size. As the fetus enlarges, so does the uterus thus affecting the position of the placenta. With that in mind, the placenta can move to the cervical area thereby obstructing the internal os. When this happens, this is termed "placenta previa".
There are different types of placenta previa: complete, partial, marginal, or low lying. Complete placenta previa is when the placenta has completely obstructed the internal cervical os. Partial placenta previa is when the placental tissue blocks only a portion of the internal cervical os. Marginal placental previa occurs when the substance extends up to but not above the internal cervical os (near proximal end of Cx). Low lying placenta, or potential placenta, is when the substance is 1cm away from internal cervical os. It is usually the low lying placenta that causes placental previa thereby inducing vascular malformation within the uterus. Another cause is abnormal uterine enlargement, which can cause the placenta to move towards the proximal end of the cervix. Below is video clip of placenta previa with the addition of abruptio placenta and the consequences that can happen with the condition.
Sunday, November 8, 2009
NIH Awards GE $1.2Million to further Push Ultrasound Technology
that's right, you heard correct...NIH recently awarded GE 1.2Million dollars to create effective ultrasound probes necessary for enchancing the quality of healthcare pertaining to ultrasound. This means that these probes will be easier to use, as well as to master, and are able to develop a clear image from the monitor. As an ultrasound tech student, this is exciting news for me, and i'm very glad that the ultrasound field is growing by the addition of these new probes that can "change the game"....to read the full article click here ....shouts to SonoWorld for the news
Sunday, September 20, 2009
First Trimester Pregnancy
First trimester of pregancy occurs from 0 to 12 weeks. This includes the ovarian, embryonic, and fetal phases of development. During the ovarian phase, follicle growth occurs from FSH, which is then followed by ovulation induced by LH. The embryonic phase occurs from weeks 6-10, in which a number of activities develop; such as the neurotube, fetal cardaic activity, transition from flat and trimlaminar embryo to C-shape, and umbilical cord. The fetal phase occurs from weeks 11-12, in which mineralization of the fetal skull and femur occurs. Below are the following activites/developments during the first trimester in their approriate weeks.
Week 1 - follice growth
Week 2 - ovulation, followed by fertilization the next day
Week 3 - Implantation of blastocyst into decidualized endometrium
Week 4 - Implantation complete, and development of gestational sac occurs. Embryo begins to grow and elongate.
Weeks 4 to 5 - neuroplate develops, which froms the neurocrest and neurotube. The neurotube eventually forms the brain and spinal cord.
Week 5 - woman's normal menstrual flow is absent, and yolk sac develops within gestational sac (suspect of pregnancy)
Weeks 6 to 10 - critical phase of human development (beginining of embryonic phase), in which the primitive heart begins to beat.
Week 6 - neurotube develops brain that consists of three segments: proencephalon, mesencephalon, and rhombencephalon.
Weeks 7 to 8 - umbilical cord develops, and appearance of embryo changes from flat and trilaminar to C-shaped embryo with limb buds.
Week 8 - mineralization of fetal skeleton begins
Week 9 to 10 - choroid plexus and falx develops
Week 10 - functional fetal kidney tissue appears
Week 11 - fetal intestinal activity begins
Week 12 - fetal swallowing develops
Weeks 11 to 12 - mineralization of fetal skull and femur occurs
Week 1 - follice growth
Week 2 - ovulation, followed by fertilization the next day
Week 3 - Implantation of blastocyst into decidualized endometrium
Week 4 - Implantation complete, and development of gestational sac occurs. Embryo begins to grow and elongate.
Weeks 4 to 5 - neuroplate develops, which froms the neurocrest and neurotube. The neurotube eventually forms the brain and spinal cord.
Week 5 - woman's normal menstrual flow is absent, and yolk sac develops within gestational sac (suspect of pregnancy)
Weeks 6 to 10 - critical phase of human development (beginining of embryonic phase), in which the primitive heart begins to beat.
Week 6 - neurotube develops brain that consists of three segments: proencephalon, mesencephalon, and rhombencephalon.
Weeks 7 to 8 - umbilical cord develops, and appearance of embryo changes from flat and trilaminar to C-shaped embryo with limb buds.
Week 8 - mineralization of fetal skeleton begins
Week 9 to 10 - choroid plexus and falx develops
Week 10 - functional fetal kidney tissue appears
Week 11 - fetal intestinal activity begins
Week 12 - fetal swallowing develops
Weeks 11 to 12 - mineralization of fetal skull and femur occurs
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