STUDY MATERIAL_.docx

THINGS TO KNOW FOR YOUR OBSTETRICS CAREER AND FOR THE EXAMS BE IT SCHOOL OR REGISTRY Define terminology related to obstetrics. The first trimester is defined as weeks 1 through 13w6d. The second trimester is defined as weeks 14 through 26. The third trimester is defined as weeks 27 through 42. A...

THINGS TO KNOW FOR YOUR OBSTETRICS CAREER AND FOR THE EXAMS BE IT SCHOOL OR REGISTRY Define terminology related to obstetrics. The first trimester is defined as weeks 1 through 13w6d. The second trimester is defined as weeks 14 through 26. The third trimester is defined as weeks 27 through 42. A normal pregnancy lasts for 9 months, 40 weeks, or 280 days. However, it may last up to 42 weeks. A pregnancy carried beyond 42 weeks is called post-term, whereas one delivered between 24 and 37 weeks is called preterm. GPTPAL G= Gravida means # of Pregnancy P= Parity (para) means # of deliveries > 20 weeks (about 4 and a half months)- PARITY- number of pregnancies in which the patient has given birth to a fetus at or beyond 20 weeks (about 4 and a half months) gestational age or an infant weighing more than 500 gms? Term= > 37 wks, < 42 wks, or >2500 gms Preterm= 24-37 wks, >500 gms <2500gms Abortion= <20 weeks, <500gms, <25cm Living Children Abbreviations used commonly. AC - abdominal circumference AFI - amnionic fluid index AGA - appropriate for gestational age BPD - biparietal diameter DM - diabetes mellitus, may see GDM (gestational DR - delivery room EDC - estimated date of confinement (due date) EFW - estimated fetal weight. FH - fundal height FHT - fetal heart tones GA - gestational age HTN - hypertension, may see CHTN (chronic) IUI- Intrauterine insemination IUP - intrauterine pregnancy IUFD - intrauterine fetal demise IDDM-insulin dependent Diabetic LGA - large for gestational age MSAFP - maternal serum alpha feto protein. NST - non-stress test; may see NST-NR (non-reactive) or NST-R (reactive) NTD - neural tube defect, e.g., meningomyelocele, spina bifida OCP - oral contraceptive pill; also written BCP (birth control pill) PID - pelvic inflammatory disease PROM (preterm = less than 37 weeks), PPROM (preterm, premature = 12 to 24 hours before labor starts SGA - small for gestational age STD - sexually transmitted disease 3VC - three-vessel cord VBAC - vaginal birth after c-section. Terms to know. Primigravida-first pregnancy Primiparous-has given birth once. Multigravida-has been pregnant more than once. Multiparous-has given birth more than once. Nulliparous-not given birth. Why is ultrasound done? What is the indication? Early pregnancy scan Viability Scan to determine pregnancy. Doctor will order a scan for Amenorrhea (meaning she did not get a period). They will determine if there is a heartbeat and if the patient becomes a “New OB” patient. This is usually done between 7-9 weeks. What are the things to assess in pregnancy by ultrasound? Uterus in sag and trans Ovaries in sag and trans Gestational sac Yolk sac CRL: crown rump length Heart rate Any pathology: Cysts What are the patient care aspects? Patients should be informed at the time of scheduling appointment to drink 32 ounces of water one hour prior to visit. Ask patient the following questions. Last Menstrual Period (LMP) Are periods regular? How many children do they have Normal delivery Any complications with prior pregnancies Indications of early first trimester scan Establish the location of the gestational sac. Confirm the intrauterine location. Document the presence or absence of yolk sac, fetal pole, and fetal number (multiple gestations) Presence of fetal heartbeat (viability). Evaluate pelvic pain. Define the cause of vaginal bleeding. Learn cause of right lower quadrant pain in pregnant patients During pregnancy, acute appendicitis is the most common complication leading to surgery. Name the soft markers for aneuploidy. • Increased nuchal translucency • Absent nasal bone • Echogenic bowel • Pyelectasis • Shortened long bones (humerus, femur) • Echogenic intracardiac focus • Choroid plexus cysts What is NUCHAL TRANSLUCENCY? NT is the sonographic appearance of a collection of fluid under the skin behind the fetal neck and back in the first trimester of pregnancy. The evaluation of the nuchal translucency has become a vital part of early first-trimester screening. Most common abnormalities associated with increased fetal nuchal translucency are trisomy 21, trisomy 18, Turner syndrome, and congestive heart failure. When NT is combined with first-trimester laboratory findings, such as hCG and pregnancy-associated plasma protein A results, a high-detection rate for these and other fetal abnormalities can be achieved. The nuchal translucency is optimally measured between 11 and 13 weeks 6 days gestation, when the crown rump length measures between 45 to 84 mm. What is NUCHAL FOLD? In the second trimester, the thickness of the nuchal skin fold is measured in a plane containing the cavum septi pellucidum, the cerebellum, and the cisterna magna. The value of skin thickness of 6 mm or less up to 20 weeks of gestational age are normal. (there are books saying 5 mm so please watch the options carefully) Fetuses with thickened nuchal skin are at increased risk for aneuploidy. What does idiopathic mean? arising spontaneously or from an obscure or unknown cause What does nosocomial mean? Originating or taking place in a hospital, acquired in a hospital, especially in reference to an infection. What is hydronephrosis? Fetal hydronephrosis dilation of the renal pelvis with or without dilation of the renal calyces. A common finding on antenatal ultrasound. In most cases, renal pelvic dilation is a transient physiologic state. Learn all the artifacts with the respective images! Learn about EFOV? Extended field of View. See more images on the NET Otherwise called panoramic view. DYNAMIC RANGE IMAGES AND FEW LINES ABOUT IT? dynamic range (DR) is defined as the difference between the maximum and minimum values of the displayed signal to display and it is one of the most essential parameters that determine its image quality. The clue should be - increase the visualization of the femur by highlighting the shades of white of the early ossified femur? What is TERATOGEN? What are the common teratogens? A teratogen is anything a person is exposed to or ingests during pregnancy that's known to cause fetal abnormalities. Drugs, medicine, chemicals, certain infections, and toxic substances are examples of teratogens. Teratogens can also increase the risk for miscarriage, preterm labor, or stillbirth. Embryonic exposure to teratogenic agents / radiation that occurs before organogenesis (0-5 WEEKS) results in either no adverse embryonic outcome or in embryonic demise. ALL OR NONE PHENOMENA Learn about ALARA Principle Gain settings do not affect patient exposure so doesn’t cause any effect. NO THERMAL BIOEFFECTS HAVE CAUSED ADVERSE EFFECTS WHEN THE TISSUE TEMPERATURE HAS INCREASED LESS THAN 2° C. Fetal tissue that lies adjacent to bone is at the greatest risk for the thermal effects of ultrasound. Reduce exposure time to keep the TI level below 1. Ultrasound modes from lowest to highest intensity: B-mode - M-mode - Color Doppler - PW Doppler. ce Learn the milestones. Learn about the hormones secretion from this table with the conditions where there is an increase or decrease. Biochemical markers Produced by what Detection in what Conditions where changes happen to the markers Alpha-fetoprotein Protein produced by the fetal yolk sac and then the fetal liver. Maternal serum ↑ INCREASED- anencephaly and cephalocele, spina bifida, gastroschisis, omphalocele, underestimated gestational age; fetus older than expected, Multiple gestations, Fetal – maternal hemorrhage, Renal anomalies, Fetal demise. ↓ DECREASED- Turners, trisomy 18, Downs syndrome, overestimated gestational age; fetus younger than expected, Chronic maternal hypertension or diabetes. Cell-free DNA Produced by the fetus Maternal serum This simple blood test can reveal gender and is also highly accurate in detecting chromosomal anomalies, including trisomy 21, 18, and 13 and sex chromosome abnormalities, as early as 9 to 10 weeks’ gestation. Structural anomalies are not detected with cfDNA, and it loses its accuracy for obese patients. Human chorionic gonadotropin Hormone produced by the placenta Maternal serum and urine ↓ DECREASED -Abortion (miscarriage), anembryonic pregnancy, ectopic, Trisomy 13 and 18, Turners. ↑ INCREASED -Molar pregnancy and Downs syndrome, Edwards Pregnancy-associated plasma protein A Protein produced by the placenta. Maternal serum ↓ DECREASED-Down syndrome (trisomy 21), ,Edwards, Turners Estriol Hormone (estrogen) produced by the placenta Maternal serum ↓ DECREASED-Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Turner syndrome ↑ INCREASED- No available data Inhibin A Hormone produced by the placenta Maternal serum ↑ INCREASED- Down syndrome (trisomy 21), Patua ↓ DECREASED- Edwards, Turners Learn about BPP (BIOPHYSICAL PROFILE) The four ultrasound aspects of BPP are. Thoracic movements which show fetal respiration or breathing Fetal movements Fetal tone Amniotic fluid NST is not a parameter ultrasound related but it is added to BPP What are the features of FAS- Fetal Alcohol Syndrome? Microcephaly Dysgenesis of the corpus callosum Long round philtrum Malformed ears Microphthalmia Heart defects - ventricular septal defects- VSD Cleft palate Fetal lie and presentation Fetal presentation is determined by identifying the fetal part that is closest to the: Learn the situs. Cephalic is when SPINE, STOMACH, UMB VN or PORTAL SINUS is clockwise in the abdominal section. Breech is when SPINE, STOMACH, UMB VN or PORTAL SINUS is anti-clockwise in the abdominal section. While evaluating the gravid patient, the sonographer should be aware of a unique situation that may arise during the examination. Patients in their late second or third trimester may suffer from supine hypotensive syndrome, which is a reduction in blood return to the maternal heart caused by the gravid uterus compressing the maternal inferior vena cava. Patients can complain of tachycardia, sweating, nausea, and pallor. The sonographer can assist the patient into a right lateral or left lateral position to alleviate symptoms. So put her in right or left decubitus position while scanning. Components of the pregnancy screening tests. TRIPLE TEST - AFP, hCG, and unconjugated estriol QUAD TEST - AFP, hCG, and unconjugated estriol, INHIBIN A INTEGRATED - I-trimester NT, [PAPP-A], and II trimester [AFP], unconjugated estriol [uE3], [hCG], and inhibin A Indication for a third-trimester sonogram evaluate fetal presentation. evaluate fetal growth. evaluate gestational age. Observation of fetal viability by visualization of cardiac motion and measuring the heart rate. Demonstration of presentation (fetal lie). Demonstration of the number of fetuses. In multiple gestations, anatomy images are obtained on each fetus, growth parameters of each fetus are obtained and compared, placenta and membrane structures are assessed, and amniotic fluid levels in each sac are documented. Characterization of the quantity of amniotic fluid as normal or abnormal by subjective visualization or by semiquantitative estimates. Characterization of the placenta, including localization and relationship to the internal cervical os. Placenta previa should be excluded by examination of the lower uterine segment. Visualization of the cervix. Transvaginal or trans-perineal imaging may be necessary to document cervical length if there are risk factors for spontaneous preterm birth, when the cervix appears shortened, or if there is a history of uterine contractions. Transvaginal cervical length measurements may be used for screening in low-risk pregnancy. Assessment of fetal age through fetal biometry. Fetal growth studies may include a serial growth analysis when serial examinations are performed at intervals that are 2 to 4 weeks apart. Typically, the following fetal measurements are included, and gestational age correlation from each measure is averaged to assess fetal age by sonography: • Biparietal diameter • Head circumference • Femur length • Humerus length • Abdominal circumference Evaluation of uterus, adnexa, and cervix to exclude masses that may complicate obstetric management. Maternal ovaries may not be visualized during the second and third trimesters of pregnancy. Anatomic survey of the fetus to exclude major congenital malformations. What stage of the conceptus does it implant inside the endometrium? BLASTOCYST By the 28th day, the blastocyst has become fully embedded within the myometrium of the uterus and implantation is complete. What is the other name of chorionic cavity? Extra embryonic coelom. Yolk sac is seen in the in the chorionic cavity. What is decidualized endometrium? The decidua is the specialized layer of endometrium that forms the base of the placental bed. Decidua basalis = between chorion frondosum + myometrium Decidua capsularis = portion protruding into uterine cavity Decidua parietalis = decidua vera = portion lining the uterine cavity elsewhere Chorion Chorion frondosum = part adjacent to decidua basalis, forms primordial placenta [ frondosum, Latin = foliage] Chorion laeve = smooth portion of chorion with atrophied villi What is vitelline duct? Connects the embryo to yolk sac. an embryonic structure providing communication from the yolk sac to the midgut during fetal development. The cord develops from the fusion of the yolk stalk and the vitelline duct (omphalomesenteric duct) early in gestation. Important facts to know. Ovulation is on DAY 14 Mature ovum is released from graafian follicle. Corpus luteum produces progesterone. Fertilization occurs in ampullary portion of tube. Fertilization 24-36 hours after ovulation Cleavage: cell division: 24-30 hours after fertilization Implantation is 6 days after fertilization. From the time of conception to 10 weeks, the conceptus is referred to as an embryo. then referred to as a fetus. 500 mIU/mL beta-hCG = gestational sac seen >8-mm gestational sac = yolk sac seen >16-mm gestational sac = embryo seen <6-mm yolk sac = normal >8-mm yolk sac = abnormal >7-mm fetal pole = positive cardiac activity Organogenesis of a fetus is normally complete by 8 weeks of gestation. BANANA SIGN AND LEMON SIGN Obliteration of the cisterna magna or effacement of the cisterna magna Cerebellum herniating into the spinal canal leading to -Banana sign Abnormal posterior fossa Abnormal fetal head shape – lemon shape ARNOLD CHIARI MALFORMATION with MENINGOMYOLOCELE – suggestive of SPINA BIFIDA Seen in Neural Tube Defects SPINA BIFIDA What is physiological herniation of the fetal bowel? As stated previously, normal bowel herniation appears sonographically as an echogenic mass at the base of the umbilical cord between 8 and 12 weeks. What are omphalocele and gastroschisis? Gastroschisis is usually visualized as an anterior wall defect, bowel containing, commonly to the right of the umbilical cord. Omphaloceles may contain abdominal organs and bowel and may protrude into the base of the umbilical cord. BECKWIDTH WEIDMAN The fetus shows bilateral enlarged kidneys with a suspicious cystic lesion on upper pole of right kidney. large abdominal wall defect covered by a wall containing only bowel loops and not the liver. macroglossia Fetal parameters were more than 90th centile and liquor was increased (amniotic fluid index 20 cm). MECKEL GRUBER Three classic features: occipital encephalocele; large, polycystic kidneys; and postaxial polydactyly. Can have spina bifida too. Few points about yolk sac It is in the chorionic cavity. Seen in the extra-embryonic coelom. Only the secondary YS is seen in the US. First structure in gestational sac – by 5.5 to 6 weeks Confirms IUP - 100% PPV Size ranges between 2 mm and 6 mm round with no other degenerative changes Method of measuring- largest diameter is measured placing calipers “inner to inner”. In a normal pregnancy the yolk sac is the first structure that is sonographically identifiable within a gestational sac and should be seen when the MSD is greater than 6.0 mm or at 5.5 weeks’ gestation The secondary or sonographic yolk sac has essential functions in embryonic development, including. (1) provision of nutrients to the developing embryo (2) hematopoiesis (3) development of embryonic endoderm, which forms the primitive gut. Pregnancies with a very large yolk sac are generally always associated with poor outcomes. Abnormalities or degenerative changes of yolk sac Large yolk sac >6mm. Small yolk sac <2mm Irregular shape. Calcified yolk sac - due to longstanding embryonic demise. IMAGES OF ABNORMALITIES OF YS Abnormal Gestational sacs – BLIGHTED OVUM or ANEMBRYONIC PREGNANCY- Anembryonic gestation refers to the presence of gestational sac without an embryo or yolk sac Imaging findings of anembryonic pregnancy Absent embryo when mean sac diameter is 18 mm Absent yolk sac when the mean sac diameter is 13 mm Irregular shape of the gestational sac Presence of fluid-fluid level or debris with bands within the gestational sac Criteria for Diagnostic of Failure of Pregnancy Ectopic pregnancy – all about it with sonographic features What is the definition of the Atrium of the lateral ventricles? Atrium, which is the widest part of the lateral ventricle at which the body, posterior horn, and temporal horn converge. What is the definition of glomus of the lateral ventricles? What are the protocols? Ask patient questions like do u have bleeding, spotting, watery discharge. Depending on facility, questionnaire may be more in depth of the obstetrics scanning? Instruct the patient to lie down on their back. Have them lower their pants to mid-thigh. Make sure to cover them with the sheet to protect privacy. Place gel on the patient’s lower abdomen Explain every step of the process (cold/warm gel) Take appropriate images. If the pregnancy is very early, trans- vaginal ultrasound may be utilized. Explain the process to the patient. Have them empty their bladder. Ask if they have a latex allergy. Put gloves on and cover the probe with the appropriate covers. Use gel inside and outside of the covering. Set the room up for the exam (put up stirrups or use wedge) Patient is put in a supine position with their feet in stirrups or wedge placed under their hips to so that the probe may be guided in Make sure the patient is all the way at the end of the table or the bed will interfere with maneuvering of the device. Always offer the patient the opportunity to guide the probe into the vagina. If they chose to guide it, DO NOT ever let go of the cord. Once the probe is in place, instruct the patient to release the probe. Maneuver the probe to get the appropriate images. Tell the patient that the exam should not hurt and to inform you if they are uncomfortable. Typically, a 3- to 5-MHz TA transducer will allow sufficient penetration in most pregnant patients, while providing sufficient resolution. These frequency ranges will vary among ultrasound equipment. While obese patients may require the use of lower frequency transducers for additional penetration, for some thin patients, especially in the first trimester, a linear transducer may be utilized to obtain high-resolution images. TV transducers should undergo high-level disinfection, and the manufacturer’s specified instructions should be followed. Laboratory findings relevant to obstetric sonography The triple screen is a maternal blood test performed between 15- 23 weeks. It includes human chorionic gonadotropin (hCG), maternal serum alpha-fetoprotein (MSAFP), and estriol. The quadruple screen adds an additional analysis of inhibin A. CYSTIC HYGROMA It is a congenital malformation resulting from lymph accumulation in the jugular lymphatic sacs due to obstruction of the lymphatic system in the fetal neck. Cystic hygromas may be septated or simple. Prenatal diagnosis - USG in first trimester Single or multilocular fluid-filled structure in the nuchal region or extending along the entire length of the fetus. Fetal genetic analysis should be offered to any patient with a first trimester cystic hygroma or significantly enlarged NT. The risk of the following anomalies associated with - Hydrocephalus - Agenesis, hypoplasia, and dysplasia of the lung - Atresia and stenosis of the small intestine – Osteo-dystrophies. - Diaphragm anomalies SPOTTERS TO KNOW A partial molar pregnancy or partial vesicular mole or partial hydatidiform mole is a pregnancy in which a molar change of the placenta is present along with presence of fetal parts or a complete fetus, which may or may not be viable. This 12-week fetus shows a viable fetus with multiple cystic lesions within the placenta. In addition, the placenta appears enlarged with increased thickness. A hydatidiform molar pregnancy is an abnormality of the placenta and rarely involves the formation of a fetus. It is marked by high levels of Human Chorionic Gonadotropin (hCG). Molar pregnancies grow much more rapidly, compared to normal fetal growth. It has the appearance of a large and random collection of grape-like cell clusters. In some cases, Xit can be malignant and requires chemotherapy or radiation treatment after surgical removal. Is the placenta low lying or not? THE IMAGE HERE HAS DISTANCE MORE THAN 2 CMS HENCE NOT LOW LYING Low lying is if the distance from the internal os to the lower edge of the placenta is less than 2 CMS. Placenta previa – PARTIAL Placenta Previa – COMPLETE PLACENTA LAKES What is the arrowhead showing? INTERNAL OS CIRCUMVALLATE OMPHALOCELES AND GASTROSCHISIS ANENCEPHALY CEPHALOCELES LABEL THE BOXES. HOLOPROSENCEPHALY WHAT ARE THE BOXES A LABEL THE NUMBERS This is an image of the gravid uterus of a 39-year-old patient who presented to the ultrasound department with a history of elevated MSAFP. She states that the fetus appears to have been moving regularly, and she has had no pain or vaginal bleeding. What is the most likely diagnosis? -ANENCEPHALY What artifact can be noted posterior to the structure identified by the arrow. SHADOWING What artifact can be noted posterior to the structure identified by the arrows? ENHANCEMENT What artifact can be noted posterior to the structure identified by the arrows? REVERBERATION The 28-week gravid patient shown below complained of right lower quadrant pain. Which of the following is demonstrated? APPENDICITIS The image below shows an amniocentesis. The arrow indicates the presence of an artifactual break in the needle. What artifact may lead to this finding? REFRACTION ARTIFACT What imaging enhancement tool is demonstrated in the image below? EFOV What would do to increase the visualization of the femur by highlighting the shades of white of the early ossified femur? DECREASE THE DYNAMIC RANGE What is demonstrated in the image shown below? ALIASING, What next to correct the artifact? Increase the PRF (scale) setting. Decrease the sample depth. Decrease the frequency. Increase the Doppler angle. Use continuous-wave transducer. What artifact is identified by the arrow in the image? Can also be like this What artifact appears as a solid streak or a chain of parallel bands radiating away from a structure? RING DOWN Protective skin covering that may be sloughed off during pregnancy is referred to as- VERNIX. What is the term for something that can cause birth defects or abnormalities within an embryo or fetus, such as alcohol and certain infections? TERATOGEN What will you do to show color Doppler flow detection in the internal jugular vein? REDUCING THE SCALE Label the images. transverse view of the brain showing the contour and shape of the fetal skull, choroid plexus (arrow) and the filling of lateral cerebral ventricles (arrow). (B, C) further evaluation of the cerebral ventricular system, in transverse planes of the brain showing the third ventricle (B) and aqueduct of Sylvius (C) (arrow). (D) mid-sagittal view of the brain showing the thalamus (Tha) and the measurements for the brain stem (BS), the fourth ventricle (IT), cisterna magna (CM), the nuchal translucency (NT) and the brain stem–occipital bone ratio (BSOB). (E) longitudinal view of the spine regularity and underlying skin (arrow). What is the general state of feeling worried and fear before confronting something emotionally or physically challenging? ANXIETY What imaging modality utilizes both features of nuclear medicine and computed tomography? PET What are the qualities of a well-cultivated critical thinker? Gathers and assesses relevant information. Asks vital questions and recognizes problems. Think with an open mind. Tests conclusion and solutions against relevant criteria Suggested daily tasks for the sonography student in clinical. replaces dirty linens after exams. completes preliminary reports assisted. informs sonographers of needed supplies. reviews protocols. What is the normal range of human hearing? BETWEEN 2 AND 20,000 HZ What term is described as reasoning or answers based on gained factual knowledge using critical thinking? INFERENCES Contrast agent used in MRI. GADOLINIUM Things provided by the sonographer on a sonographer report are. Descriptive sonographic terminology Location of pathology Measurements of normal and abnormal structures No diagnosis is to be in the report. Describe the pulse-echo technique-THE ULTRASOUND TRANSDUCER SENDS AN ULTRASOUND WAVE INTO THE BODY AND THEN LISTENS FOR THE RETURNING ECHO. What term may be used to describe the optimal location on the body for placement of the ultrasound transducer to demonstrate both normal anatomy and pathology? ACOUSTIC WINDOW The following are valid time management tools for the sonography student. Plan your week. Set your own early deadlines. Create your own academic calendar. Which imaging modality utilizes radioactive material to acquire images? - NUCLEAR MEDICINE Learn signs and symptoms and clinical findings. Differentiate sonographic findings from clinical findings? For example Clinical Murphys sign The palpable breast mass noted during an examination is a clinical finding. Sonographic findings Gall bladder wall thickening A mass noted on the kidney during a sonogram. Pericardial effusion noted during echocardiography. Vascular stenosis noted during a sonogram of the renal arteries. Which of the following techniques does not employ ionizing radiation to acquire images? MRI What are the typical ranges of diagnostic ultrasound? BETWEEN 2 AND 15 MHZ What is CSP? --CAVUM SEPTUM PELLUCIDUM- THE RECTANGULAR SPACE BETWEEN THE LEAVES OF THE SEPTUM PELLUCIDUM WITH INTERRUPTED FALX. What is Cephalic index? – A RATIO OF THE CRANIUM DERIVED TO DETERMINE THE NORMALITY OF THE FETAL HEAD SHAPE. BRACHYCEPHALIC HEAD -round shape to the fetal cranium; cephalic index 85%. DOLICHOCEPHALIC HEAD -elongated shape to the fetal cranium; cephalic index <74%. DUCTUS ARTERIOSUS-a shunt in the fetal circulation that connects the main pulmonary artery with the descending aorta; allows most of the blood from the right ventricle to the aorta to bypass the lungs. DUCTUS VENOSUS-a shunt in the fetal circulation that enables oxygenated blood to pass into the heart bypassing the liver. Following birth, it becomes the ligamentum venosum. By passes the fetal liver in fetal circulation FORAMEN OVALE-a shunt between the right and left atria that allows some blood to bypass the right ventricle. Adult life it is called FOSSA OVALIS FALX CEREBRI-a sickle-shaped fold of dura mater separating the two hemispheres of the cerebrum. MECONIUM-a material that collects in the intestines of the fetus and forms the first stool of a newborn. RAILWAY SIGN-term describing the sonographic appearance of the fetal spine. TENTORIUM-” tent” structure in the posterior fossa that separates the cerebellum from the cerebrum. THALAMUS-one of a pair of large oval nervous structures forming most of the lateral walls of the third ventricle of the brain and part of the diencephalon. VERMIS CEREBELLI-narrow is a median part of the cerebellum between the two lateral hemispheres. Biparietal diameter- BP Two-dimensional measurement. Trans Thalamic view. Measured in a plane corresponding to the widest position of the head that passes through the third ventricle and thalami. Above the level of the orbits and cerebellum. Below the level of the ventricular atrium. Transverse axial plane is most common and includes the following landmarks: Falx cerebri. Third ventricle. Thalamic nuclei. Cavum septum pellucidum Measure perpendicular to the falx, placing calipers from the outer margin of the upper cranium to the inner margin of the lower cranium. Head circumference Three-dimensional measurement. Reliable measurement independent of cranial shape. Measured in plane that must include the cavum septum pellucidum, third ventricle, thalami, and the tentorium. Measured parallel to the base of the skull, placing the calipers on the outer margins of the cranium. Abdominal circumference Three-dimensional measurement. Predictor of fetal growth, not gestational age. Most difficult measurement to obtain. Cross-sectional measurement slightly superior to the cord insertion at the junction of the left and right portal veins (hockey stick) or demonstrates a short length of the umbilical vein, left portal vein, and fetal stomach and measured at a level to include the liver. No kidney in the abdominal circumference Place calipers on the outer margins of the skin edge. Femur length One-dimensional measurement. Long bone of choice because of ease of measurement. Normal femur demonstrates a straight lateral border and a curved medial border. Measured parallel to the femoral shaft placing calipers at the level of the femoral head cartilage and the distal femoral condyle and measure only the diaphysis. Cartilaginous epiphysis is not included. Image optimization Reduce system output power control by a minimum of −3 dB (use OB presets). ALARA Place gains settings to display the myometrium hypoechoic to the normal placenta with adjustments to reduce artifactually produced echoes within the maternal urinary bladder. Focal zone(s) should be placed at or below the area of interest. The use of multiple focal zones increases detail resolution and decreases temporal resolution. Sufficient imaging depth to visualize structures immediately posterior to the area of interest. Harmonic imaging and decreasing system compression (dynamic range) can be used to reduce artifactual echoes in obese patients. Spatial compounding can be used to improve visualization of structures posterior to highly attenuating structures. Doppler settings should be adjusted for the different flow states of the fetus and adnexa. Doppler angle should be 60 degrees or less with a sample volume smaller than the vessel interrogating only exception is MCA Doppler. STRUCTURE INFORMATION SONOGRAPHIC APPEARANCE Atrium of the lateral ventricle Portion of the lateral ventricle where the body (central portion) occipital horn and temporal horn converge. Located slightly superior to the level of the biparietal diameter (BPD) Evaluated for ventricular enlargement. Hyperechoic thin ventricle wall Hyperechoic choroid plexus Measured perpendicular to the ventricle walls from the glomus of the choroid plexus to the lateral ventricular wall. Measurement should not exceed 10 mm throughout pregnancy. Choroid plexus should almost fill the lateral ventricle Cavum septum pellucidum Presence excludes central nervous system anomalies. Reservoir of cerebrospinal fluid between the frontal horns of the lateral ventricles. Found at the level of the BPD. Located inferior to the anterior horns of the lateral ventricles. Closes by 2 years of age A small anechoic rectangular box located in the midline portion of the anterior brain which interrupts the midline falx. Two hyperechoic parallel lines in the anterior midline portion of the brain Cerebellum Consists of a vermis and two lateral horns Located in the posterior fossa. Assists in balance. A dumbbell-shaped echogenic structure located in the midline of the posterior fossa. Adjunct measurement to determine fetal age. Choroid plexus Echogenic cluster of cells Important in the production of cerebrospinal fluid Not located in the anterior or occipital horns Glomus of the Choroid plexus Hyperechoic structures are located within each lateral ventricle. Lie along the atrium of the lateral ventricle. Cysts may be displayed within choroid. Cisterna magna Fluid-filled space located between the undersurface of the cerebellum and medulla oblongata. Anterior – posterior diameter ≤10 mm Measured from the cerebellar vermis to the inside of the calvaria. Cranium Begins ossification around the ninth gestational week. Generally ovoid in shape Hyperechoic outline surrounding the brain. Falx cerebri Interhemispheric fissure Separates the cerebral hemispheres. Echogenic midline linear structure Nuchal fold Soft-tissue thickness between the calvaria and posterior skin line Measured in the axial plane at a level to include the cerebellum, cistern magnum, and cavum septum pellucidum. Measured from outer cranium to outer skin line. Accurate between 15 and 21 gestational weeks Thickening associated with aneuploidy Thickness <6 mm Thalami Thalami Provide synopsis between the cerebellum and posterior brain. Hypoechoic ovoid structures in the midportion of the brain located in each hemisphere. Third ventricle is located between each individual thalamus Urinary Bladder Signifies genitourinary system is working. The bladder fills and empties every 25–30 min, approximately. Should be visualized by 13 gestational weeks Round anechoic structure located centrally in the inferior pelvis. Variable in size Stomach Reliably visualized by 13 gestational weeks. Signifies normal swallowing sequence. Anechoic structure located in the left upper quadrant. Size and shape will vary with recent swallowing. Echogenic debris within the stomach may be demonstrated Liver. Largest organ in the fetal torso. Reflects changes in fetal growth. Moderately echogenic structure. The left lobe is larger than the right lobe. Occupies most of the upper abdomen Umbilical cord insertion Smooth insertion into the anterior fetal abdomen superior to the urinary bladder. Placental insertion is generally located in the midportion of the placenta. Smooth abdominal wall at umbilical insertion (skin intact). Umbilical vein courses superiorly toward the liver. Umbilical arteries arise from the hypogastric arteries on each side of the fetal bladder. Gallbladder Visualization peaks around 20–32 gestational weeks. Signifies the presence of the biliary tree. Elongated fluid-filled structure. Located inferior and to the right of the umbilical vein Kidneys Urine formation begins near the end of the first trimester. Should be identified by 12–13 weeks. Consistently identified by 18–20 weeks. Isoechoic or hypoechoic structures are located on each side of the spine. Homogeneous, medium-gray elliptical structure on each side of the spine (sagittal plane). Homogeneous, medium-gray circular structure on each side of the spine (transverse plane). The Renal pelvis contains a small amount of fluid and measurement is <4 mm up to 33 weeks and <7 mm from 33 weeks to term. If more than 10 its abnormal A macrosomic fetus is predisposed to suffer from shoulder dystocia. All about FIBROIDS Estrogen dependent Types of fibroids (see the respective images) Submucous Subserous Intramural Signs and symptoms it can cause. Pelvic pain Enlarged uterus. Irregular bleeding, menometrorrhagia (prolonged, acyclic bleeding), or menorrhagia (prolonged, profuse bleeding) may be present. Infertility May interfere with vaginal delivery. The ureters course posterior to the uterus and ovaries. Significant mass formation in either organ can lead to extrinsic compression of the ureter and hydronephrosis. The aorta and liver circulation are not affected by an enlarged uterus. HELLP SYNDROME HELLP syndrome, which stands for hemolysis, elevated liver enzymes, and low platelet count, was said to be a variant of preeclampsia initially, but now it appears to be a separate entity. SONOGRAPHIC SIGNS Oligohydramnios IUGR Gestational trophoblastic disease Increased risk for placental abruption Elevated S/D ratio Right upper quadrant pain, nausea, and vomiting simulating gallbladder disease with HELLP syndrome Blood supply of the uterus and ovaries The uterine artery is a branch of the internal iliac artery also called hypogastric artery. Ovarian arteries arise from aorta. Ovarian vein drains into the Right side – IVC. Left side - left renal vein. UTERINE VESSELS UArRBS- you are berry sweet. Layers of the uterus Perimetrium - a double layered fibrous membrane, continuous with the abdominal peritoneum. Myometrium – thick smooth muscle layer. Cells of this layer undergo hypertrophy and hyperplasia during pregnancy in preparation to expel the fetus at birth. Endometrium – inner mucous membrane lining the uterus. It can be further subdivided into 2 parts: Deep stratum basalis: Changes little throughout the menstrual cycle and is not shed at menstruation. Superficial stratum functionalis: Proliferates in response to estrogens and becomes secretory in response to progesterone. It is shed during menstruation and regenerates from cells in the stratum basalis layer. Ligament of the uterus Broad Ligament: This is a double layer of peritoneum attaching the sides of the uterus to the pelvis. It acts as a mesentery for the uterus and contributes to maintaining it in position. Round Ligament: A remnant of the gubernaculum extending from the uterine horns to the labia majora via the inguinal canal. It functions to maintain the anteverted position of the uterus. Ovarian Ligament: Joins the ovaries to the uterus. Cardinal Ligament: Located at the base of the broad ligament, the cardinal ligament extends from the cervix to the lateral pelvic walls. It contains the uterine artery and vein in addition to providing support to the uterus. Uterosacral Ligament: Extends from the cervix to the sacrum. It provides support to the uterus. IUGR In IUGR, the fetal liver is one of the most severely affected body organs, which therefore alters the circumference of the fetal abdomen. Fetal growth restriction is used to describe a fetus that is abnormally small for gestational age, often due to complications of placental insufficiency. Fetal growth restriction describes subset of SGA fetuses with weight below 10th percentile as result of pathologic process from variety of maternal, fetal, placental disorders. BPD: Imaged in transverse plane. BPD can be misleading in cases associated with unusual head shapes. Used alone, poor indicator of IUGR. HC-to-AC ratio useful in determining type of IUGR. AC: Measure at level of portal-umbilical venous complex. Is the single most sensitive indicator of IUGR. EFW below 10th percentile considered by most to be IUGR. Fetal tissue is at the greatest risk of temperature increase due to ultrasound exposure- BONE BECAUSE OF THE HIGHEST ABSORPTION COEFFICIENT. TAMOXIFEN EFFECT IN THE UTERUS TAMOXIFEN is a Medication used as an adjunct for patients with breast cancer. Has an anti-estrogenic effect on the breast but has the opposite effect on the endometrium. Increased estrogenic effect on the endometrium increases the risk for endometrial hyperplasia, polyps, and carcinoma. Sonographic appearance Like the appearance of hyperplasia, polyps, and carcinoma Thickened with cystic changes. A hyperechoic thickened endometrium with small cystic spaces is the classic finding with tamoxifen therapy In some patients, tamoxifen is thought to reactivate adenomyosis, resulting in sub-endometrial cystic changes (most common). Types of transducers for what study transabdominal evaluation of the uterus and ovaries in a patient with a height of 5'3" and weight 275lbs- lowest possible as it gives good penetration. Look at the options and select the right shape of the TX. HYPERSTIMULATED OVARIES Ovarian hyperstimulation syndrome is a frequent iatrogenic complication of ovulation induction. The patient has severe pelvic pain, abdominal distention, and notably enlarged ovaries with severe hyperstimulation, measuring greater than 10 cm in diameter. There can also be associated ascites, pleural effusions, and numerous large, thin-walled cysts throughout the periphery of the ovary. When treated, this condition usually resolves within 2 to 3 weeks. Hyperstimulation of the ovaries, or ovarian hyperstimulation syndrome, from fertility treatment will also result in the development of multiple, enlarged follicular cysts. OVARIAN CARCINOMA- Clinical Findings of Serous and Mucinous Cystadenocarcinoma Signs and symptoms are Weight loss Pelvic pressure and swelling Abnormal vaginal bleeding Gastrointestinal symptoms Acute abdominal pain associated with torsion or rupture. Elevated CA 125 - carcinoembryonic antigen CA 125 is not a valid screening tool for ovarian cancer. It can be elevated with many different benign and malignant disorders like Endometriosis, PID, fibroids, endometrial carcinoma, and ovarian carcinoma are some of the many disorders that cause elevated serum levels of CA 125. Visualization of which of the following can help differentiate a normal intrauterine pregnancy (IUP) from a pseudo-gestational sac associated with an ectopic pregnancy? PRESENCE OF YOLK SAC Types of breech PRESENTATION Three possible breech presentations. The complete breech demonstrates flexion of the hips and knees. The incomplete breech demonstrates intermediate deflexion of one hip and knee (single or double footling). The frank breech shows flexion of the hips and extension of both knees. ABRUPTIO PLACENTA Bleeding behind or within the placenta Clinical Findings of Placental Abruption Abdominal pain (often sudden onset) Possible vaginal bleeding Uterine contraction Uterine tenderness Maternal conditions that are linked to the development of placental abruption include hypertension, pre-eclampsia, cocaine use, cigarette smoking, poor nutrition, and trauma. Hypoechoic sub-chorionic thickening, Hematoma located either at the edge of the placenta or between the placenta and the myometrium. Ultrasound detection rate - 50% Normal ultrasound does not rule out an abruption. Frequent cause of bleeding in 3rd trimester DERMOID or CYTIC TERATOMA Dermoid cysts have a varied appearance. They are the most common of the benign tumors, and is seen in young women, many of whom are asymptomatic. It is easy to pick up a Dermoid because they have very classical features: a unilocular cyst with mixed echogenicity, showing acoustic shadowing. The typical ‘white ball’ (Rokitansky nodule) is a ball of hair and sebum causing acoustic shadowing. Linear echoes are caused by the presence of hair, forming ‘lines and dots’ or ‘dermoid mesh.’ FETAL DEMISE SIGNS Signs of a demise that occurred more than 1 week ago: Spalding's sign - suture overlap on skull. Deuel’s sign/halo sign-halo effect is seen secondary to subcutaneous scalp edema in fetal demise. Robert's sign - echogenic foci (gas) in pulmonary vessels or abdomen-delayed finding (one week after demise) air in circulatory system OVARIAN TORSION Enlarged ovary. Enlarged ovary in the presence of multi-follicular development. Small peripherally located follicles on the enlarged ovary because of edema. Lack of or diminished flow patterns compared with the nonaffected ovary. “Whirlpool” sign Excessive free fluid PLACENTAL ADHERENCE TYPES ULTRASOUND APPEARANCE Placenta accreta Adherence of the placenta to the myometrium Loss of normal hypoechoic interface between the placenta and the myometrium Placenta increta Invasion of the placenta within the myometrium Loss of normal hypoechoic interface between the placenta and the myometrium with invasion into the myometrium Placenta percreta Penetration of the placenta through the serosa and possibly into adjacent organs Loss of normal hypoechoic interface between the placenta and the myometrium with penetration beyond the serosa Abnormalities Acrania The partial or complete absence of the cranium. Alpha fetoprotein elevated. Amniotic Band Syndrome The rupture of the amnion, which leads to entrapment or entanglement of the fetal parts by the “sticky” chorion. Alpha fetoprotein elevated. Anencephaly The congenital absence of the brain and cranial vault, w/ cerebral hemispheres missing or reduced to small masses. Alpha fetoprotein elevated. Aneuploidy Abnormal chromosome number. Alpha fetoprotein elevated. Beckwith-Wiedemann Syndrome Fetus increases in size, with or without organomegaly. Macroglossia, omphalocele, visceromegaly Alpha fetoprotein elevated. Cephalocele A midline cranial defect in which there is herniation of the brain and meninges. Alpha fetoprotein elevated. Cystic Hygroma Seen in the 1st trimester. Chromosomal abnormality associated w/ trisomies 13, 18, & 21. Fluid-filled structure, often with septations, initially surrounds the neck but may extend upward to the head or laterally to the body. Alpha fetoprotein elevated. Dandy-Walker Malformation Cystic dilation of fourth ventricle. Dysgenesis or agenesis of cerebellar vermis and hydrocephaly. Sixth to seventh week of gestation. Elevated tentorium. Alpha fetoprotein elevated. Encephalocele Herniation of meninges and brain through the defect. Alpha fetoprotein elevated. Exencephaly Cranial vault is absent, and the abnormal brain tissue appears as bulging masses, covered by a membrane & exposed to amniotic fluid. Alpha fetoprotein elevated. Gastroschisis Fetal bowel herniation is normal between 8-12 weeks. Usually visualized as an anterior wall defect, bowel containing, commonly to the right of the umbilical cord. Alpha fetoprotein elevated. Holoprosencephaly Failure of prosencephalon to differentiate into cerebral hemispheres and lateral ventricles between fourth and eighth weeks. Complete to partial failure of cleavage of prosencephalon Facial dysmorphism. Remember, brain appears to be single ventricle until falx cerebri develops after 9 weeks Alpha fetoprotein elevated. Iniencephaly A rare, lethal anomaly of cranial development in occiput involving the foramen magnum Extreme retroflexion of spine. Open spinal defect Alpha fetoprotein elevated. Meckel-Gruber Syndrome Encephalocele Polycystic kidneys Polydactyly Alpha fetoprotein elevated. Omphalocele Contain abdominal organs and bowel and protrude into the base of the umbilical cord. Alpha fetoprotein elevated. Pentalogy of Cantrell Rare association of cleft distal sternum, diaphragmatic defect, midline anterior ventral wall defect, defect of the apical pericardium w/ communication into the peritoneum, and internal heart defect. Omphalocele Ectopia cordis Alpha fetoprotein elevated. Spina Bifida Spina bifida occurs when the neural tube fails to close after 6 weeks of gestation. Appearances may include spinal irregularities or bulging within the posterior contour of the fetal spine and extrusion of a mass from the vertebral column. Cranial signs, the lemon sign (scalloping of frontal bones), and the banana sign (curved appearance of the cerebellum) may be appreciated closer to 12 weeks. Alpha fetoprotein elevated. Triploidy Chromosomal abnormality in which the fetus has 69 chromosomes instead of the normal 46. Small, low-set ears, cardiac defects, syndactyly, and intrauterine growth restriction. Bilateral ovarian theca lutein cysts Elevated AFP Elevated hCG Trisomy 13 Patau Syndrome Holoprosencephaly Heart defects Cleft lip and palate Omphalocele Polydactyly Talipes Echogenic chordae tendineae Renal anomalies Meningomyelocele Micrognathia Increased NT Decreased AFP Decreased hCG Decreased uE3 Decreased PAPP-A Trisomy 18 Edward’s Syndrome Heart defects Choroid plexus cysts Clenched hands Micrognathia Talipes Renal anomalies Cleft lip and palate Omphalocele Congenital diaphragmatic hernia Cerebellar hypoplasia Increased NT Decreased MSAFP Decreased AFP Decreased hCG Decreased uE3 Decreased Inhibin-A Decreased PAPP-A Trisomy 21 Down Syndrome Heart defects Duodenal atresia Shortened femurs Mild pyelectasis Mild ventriculomegaly Echogenic bowel Increased NT Decreased MSAFP Decreased AFP Decreased uE3 Decreased PAPP-A Increased hCG Increased Inhibin-A Turner’s Syndrome Monosomy X Cystic hygroma Renal anomalies (horseshoe kidneys and renal agenesis) Cardiac defects (coarctation of the aorta) Nonimmune hydrops Increased NT Decreased AFP Decreased hCG Decreased uE3 Decreased Inhibin-A Decreased PAPP-A Ventriculomegaly Dilation of ventricular system without enlargement of the cranium. Compression of choroid plexus. Increased cerebrospinal fluid Dangling choroid in dilated lateral ventricle Alpha fetoprotein is not elevated. Maternal Serum Alpha fetoprotein elevated.