Fetal Echocardiography: A Guide for Beginners
•
68 likes•10,680 views
This presentation is for those radiologists and residents who have an interest to perform advanced fetal echocardiography. Simply started and gradually covers the advanced part of it. It includes normal findings only.
Recommended
More Related Content
What's hot
What's hot (20)
Similar to Fetal Echocardiography: A Guide for Beginners
Similar to Fetal Echocardiography: A Guide for Beginners (20)
Recently uploaded
Recently uploaded (20)
Fetal Echocardiography: A Guide for Beginners
- 1. Fetal Echocardiography DR. TARIQUE AJIJ JUNIOR RESIDENT MEDICAL COLLEGE, KOLKATA
- 2. Learning objects… INTRODUCTION TIMING OF FETAL ECHOCARDIOGRAPHY EQUIPMENT LATERALITY OF FETAL BODY AND IMAGE ORIENTATION CARDIAC POSITION AND AXIS ORIENTATION SEGMENTAL ANALYSIS ECHOCARDIOGRAPHIC PROJECTIONS ROLE OF PULSED WAVE DOPPLER 3D TECHNIQUES M MODE AND ADVANCED TECHNIQUES
- 3. Introduction… Congenital malformations of the heart and arterial trunks are the most common form of congenital anomalies found in humans. It accounts for more than half of the deaths from congenital abnormalities in childhood
- 4. Prevalence Prevalence of CHD in live born Indian child Total CHD at birth 130-270,000/year Critical CHD (requiring intervention in infancy): 80,000 Critical CHD receiving treatment is only 3.04% CHD mortality as a fraction of infant mortality: 3-17% fetalechocardiography *Based on available data of CHD prevalence at birth In developed countries and present birth rates in India
- 5. Antenatal Cardiac Diagnosis Importance in developing world Limited resources to treat complex heart problems. Relatively few centres in public sector offering treatment for complex CHD. Very limited infrastructure for transporting sick neonates with critical CHDs which are correctable. Early diagnosis is a solution for this
- 6. Prevalence….only tip of iceberg! The incidence of CHD is much higher in the fetal population. Because… Number of unidentifiable cause for CHD is more than identifiable cause, so only high risk pregnancy are screened A good number of fetuses with complex cardiac anomalies succumb in the first trimester itself, even before the cardiac anomaly is suspected; Some parents opt for termination of pregnancy after the diagnosis is made in the mid-trimester Some cardiac anomalies are progressive and end in intrauterine death. Thus, the incidence quoted above may be only the tip of the iceberg.
- 7. Need for Fetal Echo! Fetal echocardiography, or the use of ultrasonic technologies to evaluate the fetal cardiovascular system, enables diagnosis of structural heart defects, and offers a way to observe complex physiological processes prior to birth Apart from training of sonographers / radiologists, high level of suspicion and detailed anatomic knowledge are mandatory Some automated 3D US also increase the sensitivity of detection
- 8. Indications for fetal echocardiography A. Maternal indications Congenital heart disease Cardiac teratogens Isotretinoin ,lithium, ethanol, phenytoin etc Maternal metabolic disorders Diabetes, phenylketonuria , gestational diabetes Autoimmune disorders Sjogrens syndrome , SLE Intrauterine infections Rubella B. Fetal indications: Extra cardiac anamolies Chromosomal and Anatomic(increased NT , GIT , RENAL , CNS ) Fetal cardiac arrythmias Irregular rhythm , tachycardia(absence of amnionitis) , bradycardia Non immune hydrops Abnormal fetal situs Suspected fetal heart anomaly by screening ultrasound Chromosomal abnormalities Monochorionic twin gestation Twin twin transfusion syndrome, conjoint twins
- 9. Indications for fetal echocardiography C. Familial indications : History of CHD Previous sibling , paternal Mendalian syndromes Williams syndrome , Digeorge syndrome Consanguinity D. Indications for converting a routine scan into fetal echocardiography Chamber asymmetry Altered cardiac axis Altered position of the fetal heart Enlarged fetal heart Arrhythmia
- 10. TIMING OF FETAL ECHOCARDIOGRAPHY Fetal echocardiography is best performed between 18 and 22 weeks of gestation. After 30 weeks gestation, the shadowing effects of the fetal ribs, ratio of fetal body mass-to-amniotic fluid increases so acquisition of images more difficult. Early maternal transabdominal or trans-vaginal scan at 11 to 14 weeks of gestation, in pt with Increased nuchal translucency. In the first trimester (11–14 weeks), cardiac details may not be elicited well, but the presence of a pulsatile ductus venosus or tricuspid regurgitation can be a very strong marker for cardiac and chromosomal anomalies.
- 11. Equipment &Technical aspects High frequency transducers probes for resolution and details Phased array transducers with fundamental frequencies between 4 and 12 MHz are generally used. Curvilinear probe with wider near- field of view. High frequency transducers with a narrower footprint Low frequency transducers and harmonic imaging ---3rd trimester and axial resolution of 1 mm or less this is particularly important given the small size of critical fetal cardiac structures. Frames rates of 80 to 100 Hz are frequently needed to view important events occurring at heart rates in excess of 140 beats per minute
- 12. Equipment &Technical aspects The system should have the ability to zoom the image without causing deterioration of image quality. A higher pulse repetition frequency (PRF) is required for colour Doppler in the fetus as compared to the settings used for routine obstetric colour Doppler. Role of Color Doppler: Increase accuracy Speed up examination
- 13. Role of Color Doppler: Image optimization Smallest color box possible to maintain the frame rate as high as possible (20-25 fps is real time to eye)
- 14. Role of Color Doppler: Image optimization Velocity Scale / PRF: High-velocity range (> ± 30 cm/sec): atrioventricular valves, the semilunar valves, and the great vessels Low- to mid-velocity scales (10 - 20 cm/sec): pulmonary and caval veins
- 15. Role of Color Doppler: Image optimization Color Filter / Wall Filter: high filter: for aorta Low filter: for pulmonary artery Low Color Persistence Optimum color gain: The color gain in cardiac imaging should therefore be initially set on low and gradually increased until the color information is optimized. Color Doppler Image Resolution and Color Line Density: compromise between high resolution and frame rate.
- 16. Image orientation First step in the ultrasonographic evaluation of the fetal heart is the assessment of the fetal visceral situs Allows for an accurate determination of ventricular and atrial situs Abnormal situs associated higher CHD Fetal situs determination can be done by: Position of the stomach and heart in the abdomen and chest respectively Position of the aorta and inferior vena cava below the diaphragm Presence of bowel dilatation The presence of a gallbladder The presence and location of the spleen
- 17. Image orientation Techniques: Determine the presenting part Determine the fetal lie within the uterus by obtaining a sagittal view of the fetal spine. determine the location of the fetal left side with regard to the maternal abdomen Fetal left side is anterior [closer to the transducer] Posterior [closer to the posterior uterine wall] Right lateral [closer to maternal right uterine wall] Left lateral [closer to maternal left uterine wall] Obtain a transverse view of the fetal abdomen by rotating the transducer 90 degrees from the sagittal view of the lower thoracic spine
- 18. Image orientation The fetal stomach is imaged in the left side of the abdomen, the descending aorta is posterior to the left, and the inferior vena cava is anterior to the right sliding the transducer toward the fetal chest, a four-chamber view of the heart is imaged the apex of the heart is pointing toward the left side of the fetal chest
- 19. Image orientation Most common used method for assesing laterality is proposed by Cordes et al. It is easy when fetus is in transverse position Procedure: 1. Obtaining sagittal view of fetal body. Align transducer in long axis of fetus (spine) 1. Orient the transducer so that fetal head is on the right side of observer on the screen 2. Rotate the transducer 90* clockwise to obtain a transverse view of fetal body 3. Tranverse section thus aquired is caudocranial axis
- 21. Image orientation Another method reported by Bronshtein et al right-hand rule for abdominal scanning and the left-hand rule for transvaginal scanning hand corresponds to the face of the fetus, and the examiner holds the hand according to the side of the fetal face the fetal heart and stomach are shown by the examiner’s thumb
- 22. Image orientation Craniocaudal Caudocranial (standard view) anatomical
- 23. Cardiac position and Axis orientation Cardiac position and axis can be assessed in four chamber view In this view by tracing sagittal and coronal planes through centre of thorax four quadrants are identified Lv and most of RV and anterior part of LA lie in left anterior quadrant
- 24. Cardiac Axis Normal value: 45˚ ± 20˚
- 25. Cardiac Axis Left Axis Deviation: tetralogy of Fallot, coarctation of the aorta and Ebstein anomaly Right Axis Deviation: double outlet right ventricle, atrioventricular septal defect, and common atrium Abnormal cardiac axes are also noted in fetuses with abdominal wall defects such as omphaloceles and gastroschisis In rare occasions involving complex congenital heart disease, the apex of the heart may not be identifiable
- 26. Cardiac Position Position of the heart within the chest and is independent of the fetal cardiac axis, fetal situs, cardiac anatomy, or chamber organization. Dextrocardia Mesocardia Levocardia
- 27. Cardiac Position Dextroposition and Dextroversion Dextroposition of the heart, a form of dextrocardia, refers to a condition in which the heart is located in the right chest and the cardiac apex points medially or to the left occurs in results from extrinsic factors like diaphragmatic hernia, left lung mass, left pleural effusion, agenesis of the right lung When the heart is located in the right chest with the cardiac axis pointing to the right side, the term dextroversion has been used and is found in situs inversus and situs ambiguous
- 28. Cardiac Position Levocardia can be associated with normal situs (normal anatomy), situs inversus, or situs ambiguous Levoposition is usually in association with a space-occupying lesion on the right side Mesocardia associated with abnormal ventriculoarterial connections such as transposition of great vessels and double outlet right ventricle
- 29. Cardiac dimensions Cardiothoracic (C/T) ratio: fairly constant throughout gestation, with a mean value of 0.45 at 17 weeks and 0.50 at term (range: 0.25 - 0.35) Cardiomegaly: C/T area greater than 2 standard deviations An increased C/T circumference can also be observed in the presence of reduced chest volume rather than an enlarged heart, and thus, it is important to compare the measured chest circumference to gestational age nomograms as part of this evaluation May be seen in skeletal dysplasia, pulmonary hypoplasia.
- 30. Sequential cardiac examination Identify the chamber by morphology not by anatomy!
- 31. Internal Cardiac anatomy: RA
- 32. Internal Cardiac anatomy: Tricuspid valve three leaflets—anterior, septal, and posterior chordae tendineae papillary muscles: Ant, post and septal Chordae tendineae from the valve leaflets insert directly into the septal wall, a feature found only in the right ventricle Unlike the mitral valve, a subpulmonic conus separates the tricuspid valve from the pulmonary valve, resulting in no fibrous continuity between the two
- 33. Internal Cardiac anatomy: RV
- 34. Internal Cardiac anatomy: LA
- 35. Internal Cardiac anatomy: Mitral valve Two leaflets – anteromedial & posterolateral anterolateral and posteromedial papillary muscles anteromedial leaflet, attaches primarily to the anterolateral papillary muscle and is in fibrous continuity with the aortic valve
- 36. Internal Cardiac anatomy: LV The ventricles are separated by the ventricular septum. The apical portion (near the cardiac apex) is muscular in origin, and the basal portion (near the atrioventricular valves) is membranous.
- 37. Echocardiographic projections: Abdominal circumference Four-chamber view Five-chamber view Three-vessel view Transverse view of the arterial duct (ductus arteriosus) Transverse view of the aortic arch Three-vessel-trachea view (transverse view of aortic and ductal arches)
- 38. Echocardiographic projections: Technique Determine the fetal situs Obtain a four-chamber view left ventricular outflow tract (the aorta), referred to as the five-chamber view, can be imaged by a slight tilt or rotation of the medial aspect of the transducer in the direction of the fetal head From the four-chamber view, the three-vessel view can be imaged by sliding the transducer cranially while maintaining the transverse orientation in the chest From the three-vessel view, the transverse view of the arterial duct can be obtained by a slight cranial tilt of the transducer From the transverse view of the arterial duct, the transverse view of the aortic arch can be obtained by a slight cranial slide of the transduce From the transverse view of the aortic arch, the three- vessel-trachea view can be obtained by slightly angulating the transducer caudally and to the left
- 39. Abdominal plane Upper Abdomen: to see hepatic veins, umbilical veins and ductus venosus. This plane is also useful to describe vein anomalies in suspected heterotaxy and R/O ductus agenesis
- 40. 4 Chamber View Scanning Technique 1. Determine the fetal situs 2. Obtain a transverse plane of the fetal abdomen: full length rib is visible 3. slide the transducer toward the fetal chest till proper 4 chamber view is obtained Criteria of good view: Complete rib on both side Apex Inferior pulmonary vein draining posteriorly in LA
- 41. 4 Chamber View Types of Four-chamber View: apical four-chamber view basal four-chamber view apex of the heart, the ventricles, the atrioventricular valves, and longitudinal atrial and ventricular dimensions long-axis or axial four-chamber view atrial and ventricular septae
- 42. Role of Color Doppler: Image planes The four-chamber plane in color Doppler is best visualized from an apical (A) or a basal (B) view in order to demonstrate ventricular filling either in red (A) or in blue (B) in diastole. In these orientations, the course of blood flow is nearly parallel to the angle of insonation. No flow is present during ventricular systole unless TR is present.
- 43. 4 Chamber View
- 44. The Five-chamber View Five-chamber view of the fetal heart demonstrating the continuity of the posterior wall of the aorta with the mitral valve (small arrows) and the continuity of the anterior wall of the ascending aorta (AAo) with the ventricular septum (asterisks). The inflow and outflow components of the left ventricle (LV) are seen in one view (open arrow). The right and left superior pulmonary veins (RSPV, LSPV) enter the posterior wall of the left atrium at this level. RV, right ventricle; LA, left atrium; DAo, descending aorta; L, left. Five-chamber view of the fetal heart demonstrating the wide angle between the direction of the ventricular septum and the anterior wall of the ascending aorta (AAo). This important anatomic observation is commonly absent in conotruncal malformations. LV, left ventricle; RV, right ventricle; LA, left atrium; DAo, descending aorta; L, left.
- 45. Role of Color Doppler: Image planes Five-chamber View: Demonstrating aortic blood flow in blue color within the ascending aorta or from a basal view (right side of fetus) demonstrating aortic blood flow in red color within the ascending aorta Color Doppler of the five-chamber view in the normal fetus shows the septo-aortic continuity, the absence of turbulences in systole, and insufficiency in diastole across the aortic valve
- 47. The Three-vessel View pulmonary trunk in an oblique section and the ascending aorta and the superior vena cava in transverse sections
- 48. Role of Color Doppler: Image planes Short-axis or Three-vessel View: show pulmonary blood flow in blue color demonstrating the nonturbulent flow across the pulmonary valve and the bifurcation into the right and left pulmonary arteries
- 50. The Transverse View of the Arterial Duct main pulmonary artery with the ductal branch joining the descending aorta to the left of the spine
- 51. The Transverse View of the Aortic Arch the transverse aortic arch and the superior vena cava
- 52. Three-vessel-trachea View (Transverse Duct and Aortic Arch View)
- 53. Role of Color Doppler: Image planes Three-vessel-trachea View: Most important plane aortic and ductal arches forming a ‘‘V- configuration Turbulent flow, reversal flow, size discrepancy, or even absence or interruption of a vessel can be easily assessed
- 54. Sagittal Views Inferior and superior vena cava view Aortic arch view Ductal arch view
- 55. Sagittal Views Techniques: 1. Determine the fetal situs 2. Obtain a sagittal view of the thoracic fetal spine. 3. sliding the transducer from the right parasagittal to the left parasagittal chest while maintaining a sagittal orientation, three ultrasound planes can be imaged: i. the superior and inferior venae cavae ii. the aortic arch iii. the ductal arch
- 56. Sagittal Views : The Inferior and Superior Vena Cava View
- 57. Sagittal Views : The Aortic Arch View
- 58. Role of Color Doppler: Image planes Longitudinal Views of Aortic and Ductal Arches: often power doppler and bidirectional HD color may be needed.
- 59. Sagittal Views : The Ductal Arch View sagittal or parasagittal approach
- 60. Sagittal Views : The Ductal Arch View (Sagittal)
- 61. Sagittal Views : The Ductal Arch View (Parasagittal)
- 62. Oblique Views Right ventricular outflow view (short axis) Left ventricular long-axis view Ventricular short-axis views
- 63. Oblique Views Scanning techniques: Determine the fetal situs Obtain a midsagittal plane of the fetal chest The right ventricular outflow view: angling the transducer to an oblique plane that is oriented from the right iliac bone to the left shoulder of the fetus The left ventricular outflow view: angling the transducer to an oblique plane that is oriented from the left iliac bone to the right shoulder of the fetus
- 64. Oblique Views : Right Ventricular Outflow View
- 65. Oblique Views : Left Ventricular Outflow View
- 66. Short Axis view Scanning Technique 1. Determine the fetal situs 2. Obtain a four-chamber-view 3. rotate the transducer 90 degrees to obtain short-axis views of the heart 4. Serial short-axis views of the heart, from the apex of the left ventricle to the pulmonary artery bifurcation, can be obtained by slight anterior-to- posterior (apical-to-basal) angulation of the transducer
- 67. Short Axis view Utility: spatial relationship of cardiac chambers ventricular size, ventricular wall, and septal thickness orientation of the great vessels and their divisions
- 68. Short Axis view: At the ventricular level Compare both ventricular wall thickness Right ventricle identified by irregular wall Compare the papillary muscles of left ventricle (anteromedial vs posterolateral) IVS
- 69. Short Axis view: At the AV valve mitral valve, with its anterior and posterior leaflets, is crescent shaped and has the appearance of a fish mouth tricuspid valve is more apically placed in the heart than the mitral valve
- 70. Power doppler and bidirectional HD color Enhanced sensitivity: amplitude of Doppler signals instead of their frequency shift is detected Improved noise differentiation: In power Doppler, noise signals are encoded in a uniform color Enhanced edge definition: This is because color signals, which extend partially beyond the edges, have lower signal amplitude due to the lack of moving erythrocytes and are thus not displayed Flow detection irrespective of angle insonation: The amplitudes of the positive and negative components of the flow tend to add up, resulting in a powerful signal Disadvantages of power Doppler in fetal cardiology include the lack of information on direction of blood flow and on the presence or absence of turbulence combining the Doppler frequency shifts with signal amplitude, digital broadband assessment of Doppler signals is applied providing a very sensitive tool known as advanced dynamic flow or ‘‘high-definition (HD) flow’’ higher resolution, good lateral discrimination, and higher sensitivity
- 71. Power doppler and bidirectional HD color
- 72. Role of Pulsed wave Color Doppler Δf = (2f0Vcosθ)/c Doppler frequency shift therefore reflects but does not actually measure the velocity of blood flow To obtain absolute value, we need to insonate within 10-15˚ Sample volume is kept distal to the valve Multiple measures taken and also during fetal apnea Color Doppler is used to direct placement of the sample volume
- 73. Doppler Indices Peak velocity: The maximum velocity on the Doppler spectrum (cm/sec) Time-to-peak velocity (TPV): The time from onset to peak velocity (msec), also referred to as acceleration time Deceleration time: The time from the peak of the waveform to the intersection of the descending slope with the baseline (msec) Time-velocity integral (TVI): The measurement of the area under the Doppler waveform over one cardiac cycle (cm) Time-averaged velocity (TAV): TVI divided by the period time (cm/sec)
- 74. Doppler Indices E/A ratio: A measurement used to quantify Doppler waveforms across the atrioventricular valves. E represents peak velocity during early ventricular filling, and A represents peak velocity during the atrial contraction Filling time: The diastolic time of the cardiac cycle (msec) Ejection time: The systolic time of the cardiac cycle (msec)
- 75. Doppler Indices Percent reverse flow: A measurement used to quantify Doppler waveforms in the inferior vena cava. It represents TVI of the reverse flow segment (atrial contraction) divided by the TVI of the total forward flow and multiplied by 100
- 76. Doppler Indices S/A: A measurement used to quantify Doppler waveforms in the ductus venosus. S represents maximum systolic velocity and A represents the atrial nadir
- 77. Doppler Indices
- 79. PW Doppler at AV valve Doppler waveform across the mitral valve shows aortic flow during the systolic component due to leaflet continuity between the mitral and aortic valve annuli The E/A ratio is an index of ventricular diastolic function in the fetus the velocity of the A wave is higher than that of the E wave As ventricular stiffness decreases with advancing gestation, E/A ratio increases from 0.53 ± 0.05 in the first trimester to about 0.70 ± 0.02 in the second half of pregnancy The rise in E/A ratio with advancing gestation suggests a shift of blood flow from late to early diastole
- 80. PW Doppler at semilunar valve
- 81. PW Doppler at IVC These waveforms are triphasic with the first phase corresponding to ventricular systole (S); the second phase corresponding to early diastole (D); and the third phase (reverse flow) corresponding to the atrial contraction (A) The percentage of reverse flow, which is a ratio of the time velocity integral during the atrial contraction divided by the time velocity integral during total forward flow, is used for Doppler waveform quantification in the inferior vena cava
- 82. PW Doppler at Ductus Venosus Approach to imaging of the ductus venosus (DV) on color Doppler. In A, a coronal plane of the chest shows the DV as it joins the inferior vena cava (IVC) toward the right atrium (RA). The hepatic vein (HV) is also seen in this plane. In B, a parasagittal plane shows the DV originating from the umbilical vein (UV), and in C, a transverse plane of the abdomen shows the DV as it originated from the UV. Note the presence of color aliasing in the DV in the three planes.
- 83. PW Doppler at Ductus Venosus Doppler waveforms are biphasic in morphology with a first peak concomitant with systole (S); a second peak concomitant with early diastole (D); and a nadir concomitant with the atrial contraction (A) forward flow is present throughout the entire cardiac cycle in the ductus venosus in the normal human fetus Two such indices were developed based on peak velocities during systole and during the atrial contraction (S/A, S-A/S)
- 84. PW Doppler at Pulmonary veins
- 85. 3D Ultrasound 3-D ultrasound provides a volume of a target anatomic region, which contains an infinite number of 2-D planes Optimization of 3D image needs optimization of reference image which is 2D image Infinite number of planes are acquired parallel to reference plane Images are reconstructed in orthogonal and oblique planes or volume / surface rendered Resolution is best in reference & its parallel planes reference plane should therefore be chosen based on the anatomic region of interest within the heart 4 chamber plane: cardiac chambers, origin of great vessels, and the three-vessel and three-vessel- trachea views Sagittal plane: aortic, ductal arches and venous connections
- 86. 3D Ultrasound: few terms ROI box: height and width, corresponding to the x and y axes. It should be smallest for fastest acquisition and better resolution Angle of acquisition: sweep angle of the elements within the probe and is adjusted by the operator. It refers to the depth of a volume, corresponding to the z axis For static 3D: 40 – 45˚ For STIC: 20 - 35˚ Smaller angle: fastest acquisition Quality of acquisition: number of planes acquired within a volume. For static 3D: low, medium or high For STIC: 7.5, 10, 12.5, or 15 seconds
- 87. Static Three-dimensional (Direct Volume Scan: Nongated) contains an infinite number of 2-D still ultrasound planes with no regard to temporal or spatial motion Rapid acquisition & easy volume manipulation and also large volumes Acquisition can be compiled with power doppler or B flow image inability to assess events related to the cardiac cycle, valve motion in the heart, and myocardial contractility
- 88. Spatio-temporal Image Correlation (STIC) (Indirect Volume Scan, Motion Gated: Offline Four- dimensional) It is an indirect, motion-gated, offline mode based on the concept of using tissue excursion concurrent with cardiac motion to extract the temporal information regarding the cardiac cycle The acquired volume is processed internally, where the systolic peaks are used to calculate the fetal heart rate and the volume images are then rearranged according to their temporal events within the heart cycle, thus creating a cine-like loop of a single cardiac cycle assess atrial and ventricular wall motion and valve excursion and combined with Doppler delayed acquisition time
- 89. Real-time Three-dimensional (Direct Volume Scan, Real Time, Online Four-dimensional) Done by mechanical transducer rotation or by matrix transducer gating of the heart rate is not required and volumes of the beating heart are displayed instantaneously without any transfer or postprocessing of the data Color Doppler can also be added acquired volume, often too small
- 90. Volume manipulation Volume Display in Two-dimensional Planes: Single Two-dimensional Planes or Multiplanar Orthogonal Display Both for static 3D or STIC Multiplanar Tomographic Ultrasound Imaging Volume Display in Rendering: display of external or internal surfaces of acquired volumes
- 91. Volume manipulation Manipulation of a spatio-temporal image correlation (STIC) volume. A: The original STIC data set is shown in an orthogonal plane display. The four-chamber plane as a ‘‘single plane’’ is demonstrated in systole (B) with closed atrioventricular valves and in diastole (C) with opened valves. Scrolling through the volume demonstrates the upper abdomen with the stomach (ST) (D), the slightly oblique five-chamber view (E), the three-vessel-trachea view in the upper thorax (F) a reconstructed longitudinal plane (G) of the aortic arch.
- 92. Volume manipulation Spatio-temporal image correlation (STIC) volume in a fetus with an atrioventricular septal defect. In plane A, the defect is not clearly demonstrated as the valve leaflets are closed. By scrolling through the cursor (open arrow), the interventricular septal defect is clearly demonstrated (asterisk) in plane B when the valve leaflets are open. Tomographic ultrasound imaging of spatio-temporal image correlation (STIC) volume of the fetal heart in gray scale. In the upper left image, the orientation plane A is seen (highlighted in yellow) with the parallel vertical lines referring to the planes shown in the display (-4 to +4). Interplane distance and total number of planes are chosen by the examiner
- 93. Volume Display in Rendering Surface Mode Display
- 94. Volume Display in Rendering Transparent Minimum Mode: anatomic details of structures are limited, but the projection of anechoic structures such as the cardiac chambers and great vessels allows for a useful display of cardiac anatomy.
- 95. Volume Display in Rendering Inversion Mode:
- 96. Volume Display in Rendering Three-dimensional Color Doppler and Glass Body Mode
- 97. Volume Display in Rendering Three-dimensional B-flow Rendering
- 98. M-mode Echocardiography The M-mode display is a linear representation of adjacent cardiac structures as a function of time accurate and reproducible measurements of various cardiac chambers and great vessel diameters The M-mode cursor is often placed to intersect an atrium and a ventricle so that the relationship of atrial to ventricular contractions is recorded
- 99. Color Doppler M Mode Colors are added to accurate the systole and diastolic component.
- 100. Tissue Doppler Imaging By sampling atrial and ventricular wall motion, however, tissue Doppler can provide accurate measurements of cardiac intervals and cardiac wall velocities
- 101. Calculation of MPI (myocardial performance index)
- 102. Reporting
Editor's Notes
- Color persistence allows information from prior images to be overlapped on the current image, superimposing color signals from different phases of the cardiac cycle and thus reducing the impression of pulsation
- Image orientation and determining the laterality of fetal body is important.
- This continuity is disrupted in the presence of aortic override absent in conotruncal anomalies (more parallel orientation with the ventricular septum)
- This view is useful in assessment of conotruncal abnormalities. Abnormalities may involve vessel size, vessel alignment, vessel arrangement, vessel number, and location of descending aorta
- Both arches are located to the left of the spine and trachea, an important anatomic landmark because no vessel is seen to the right of the trachea in normal cardiovascular anatomy
- ductal arch is seen to arise from the anterior aspect of the chest, with a wide, angular curvature, almost perpendicular to the descending aorta
- secondary to an increase in ventricular compliance, a rise in ventricular relaxation rate, or a reduction in afterload with decreased placental resistance Abnormal findings: decrease mitral flow in HLHS, aortic stenosis, reversed flow in endocardial fibroplasia. Decrease tricuspid flow in HRHS or tricuspid atresia, reversed flow in TR
- Peak systolic velocity and time-to-peak velocity are the most commonly used indices for Doppler waveform quantification Peak systolic velocity is a function of myocardial contractility, valve annulus size, preload, and afterload time-to-peak velocity is a function of mean arterial pressure peak systolic velocity and time-to-peak velocity increase with advancing gestation Peak systolic velocity is greater in the aorta than in the pulmonary artery due to larger annulus in the pulmonary artery or a decreased afterload in the aorta secondary to the cerebral circulation Time-to-peak velocity is shorter in the pulmonary artery than in the aorta, which suggests a higher mean arterial pressure in the pulmonary artery in the fetus Abnormal finding in AS, Coarctation, PS, PR
- This index of flow is a reflection of the pressure gradient between the right atrium and the right ventricle at end diastole, which is dependent on ventricular compliance and end diastolic pressure within the right ventricle The percentage of reverse flow in the inferior vena cava decreases linearly with advancing gestation In IUGR reverse % flow is increased
- reduced, absent, or reversed flow in the atrial contraction portion of the waveform (A) (Fig. 8-24). Abnormal DV waveforms may also be seen in obstructive lesions of the right heart.
- Abnormal pulmonary vein Doppler waveforms are seen in fetuses with hypoplastic left heart syndrome with narrow interatrial communication showing flow reversal during late diastole (see Fig. 11-25). In fetuses with anomalous venous connections, Doppler of the pulmonary veins shows absence of the typical triphasic shape.
- records ultrasound beam reflections in relation to depth from the transducer and time.