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Segmental approach to Congenital Heart Disease

Segmental approach to Congenital Heart Disease: From Developmental Anatomy to Pathology

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Segmental approach to Congenital Heart Disease

  1. 1. SEGMENTAL APPROACH TO CONGENITAL HEART DISEASE FROM DEVELOPMENTAL ANATOMY TO PATHOLOGY TANATTABTIEANG, MD ADVISOR:Assist. Prof. MONRAVEE TUMKOSIT, MD RADIOLOGIST Division of Diagnostic Radiology, Department of Radiology Faculty of Medicine, Chulalongkorn University King Chulalongkorn Memorial Hospital (KCMH)
  2. 2. CONTENTS  Van Praagh Classification System  Related Embryology  Step 1: Visceroatrial situs  Step 2: Ventricular Loop Orientation  Step 3: Position and Relation of the GreatVessels  Assessment of Connecting Segments  Example Cases from KCMH  Summary
  3. 3. VAN PRAAGH CLASSIFICATION SYSTEM  “Segmental” approach to the heart  Developed and implemented in 1960s in Boston, MA  Most widely used in the imaging workup of congenital heart disease in North America  Facilitating communication in diagnosis, characterization and management  Three part notation  Three-part series of letter  Corresponding to key segment of embryologic region of cardiac anatomy BostonChildren’sHospital
  4. 4. VAN PRAAGH CLASSIFICATION SYSTEM  “Sequential” segmental analysis  Developed by Anderson and colleague in 1970s  Emphasizing how the chamber are connected and related  Atrioventricular (A-V) junction  Ventriculoarterial (V-A) junction { _ , _ , _ } Visceroatrial situs Ventricular loop orientation Position and relation of the Great vessels
  5. 5. Step 1 Visceroatrial situs Step 2 Ventricular loop orientation Step 3 Position and relation of the Great vessels Segments: Connections: Atrioventricular junction Ventriculoarterial junction Put it all together
  6. 6. RELATED EMBRYOLOGY  Primodial (primitive) heart tube  Initially straight  Atrial portion receive venous blood from left & right sinus venosus  Sinus venosus receives the umbilical, vitelline, and common cardinal veins from the chorion, umbilical vesicle, and embryo, respectively Truncus arteriosus Bulbus cordis Single ventricle Primitive atrium Sinus venosus NeillC,2006
  7. 7. RELATED EMBRYOLOGY  Normal looping (D-loop)  Begins to loop inside pericardial sac at approximately 23 to 28 days of gestation (bulboventricular loop)  The primitive heart tube grows, loops anteriorly and to the right  Cephalic end of heart tube bends ventrally, caudally, and slightly rightward  Bulbus cordis located to the right of LV, result in RV on the right  Heart rotate in to left thorax, heart apex pointing to the left TA (future great vessels) BC (future RV) Ventricle (future LV) Primitive atrium MooreKL,2016 NeillC,2006
  8. 8. RELATED EMBRYOLOGY  Partitioning of truncus arteriosus  Aorticopulmonary septum formation during 5th week  When partitioning of the truncus arteriosus is nearly completed, the semilunar valves begin to develop around the orifices of the aorta and pulmonary trunk. MooreKL,2016
  9. 9. Posterior Anterior LeftRight Moore KL, 2016
  10. 10. RELATED EMBRYOLOGY  Development of cardiac valves  Muscle under aortic valve is resorbed  Atrioventricular (mitroaortic) fibrous continuity  Subpulmonary muscle (conus) grows  Pulmonary valve locates farther from AV valves without fibrous continuity  After resorption of muscle, aortic valve lies posterior and rightward of the pulmonary valve  Semilunar valves undergo 150° counterclockwise rotation  Aorta connect to LV and the main PA connect to RV Posterior Anterior ~150° Neill C, 2006
  11. 11. Netter FH, 2014
  12. 12. Atrioventricular (mitroaortic) fibrous continuity Netter FH, 2014
  13. 13. Anterior Posterior RightLeft Aortic valve lies posterior and rightward of the pulmonary valve Netter FH, 2014
  14. 14. RELATED EMBRYOLOGY  Development of venous structures  At 4th week, three pairs of venous system drain into the primordial heart  Posterior cardinal veins drain caudal parts of the embryo  Subcardinal and supracardinal veins gradually develop and replace and supplement the posterior cardinal veins MooreKL,2016
  15. 15. RELATED EMBRYOLOGY  Development of venous structures  Above the kidney, they are united and becomes azygos and hemiazygos veins  Below the kidneys, the left supracardinal vein degenerates, but right supracardinal vein becomes the inferior part of the IVC MooreKL,2016
  16. 16. RELATED EMBRYOLOGY  The IVC is composed of four main segments  A hepatic segment derived from the hepatic vein (proximal part of the right vitelline vein) and hepatic sinusoids  A prerenal segment derived from the right subcardinal vein  A renal segment derived from the subcardinal– supracardinal anastomosis  A postrenal segment derived from the right supracardinal vein MooreKL,2016
  17. 17. TERMINOLOGY  In congenital heart approach  A structure named as “right” or “left” because it normally be found on the right or left side, e.g., right ventricle or left ventricle  Regardless of whether it is actually on which side of the patient  E.g., if the patient left atrium is on the right side, it would still be called the left atrium because of its characteristic structure  The word morphologic is used to indicate that the internal characteristic structure is meant, without implication about the actual location of the structure
  18. 18. TERMINOLOGY  Position of the heart in thorax and orientation of cardiac apex are contributive to but not determinative of the situs  Help predict the incidence of congenital heart disease  Cardiac position  The position of the greater mass of the heart with respect to the sternum  Levoposition : mainly in the left chest  Mesoposition : midline positon of the heart  Dextroposition : mainly in the right chest  Cardiac base-apex axis may be oriented normally  May caused by extrinsic factor, e.g., hypoplasia or agenesis of lung
  19. 19. TERMINOLOGY  Cardiac orientation  When the cardiac axis has the same directional orientation as greater mass of the heart  Levocardia  Mesocardia  Dextrocardia MazurW,2013
  20. 20. Dextrocardia: an abnormal cardiac position at the right of the sternum, combined with an abnormal rightward orientation of the cardiac axis. Dextroposition: an abnormal cardiac position at the right of the sternum, combined with a normal leftward orientation of the cardiac axis, secondary to right lung hypoplasia due to right pulmonary vein atresia. RadioGraphics 2013; 33:E33–E46
  21. 21. STEP 1 VISCEROATRIAL SITUS { X , _ , _ }
  22. 22. VISCEROATRIAL SITUS  Relationship between the atria and the adjacent organs  Three type of situs  Situs solitus { S , _ , _ }  Situs inversus { I , _ , _ }  Situs ambiguus { A , _ , _ } { X , _ , _ }Visceroatrial Situs
  23. 23. 1. Visceral situs  Determining whether liver, stomach and spleen located on patient’s right or left side 2. Thoracoabdominal situs  Determining structure of bronchopulmonary anatomy 3. Morphologic RA  Identify the morphologic RA Visceral Situs Thoraco- abdominal Situs Atrial Situs VISCEROATRIAL DESIGNATION { X , _ , _ }Visceroatrial Situs
  24. 24. Determining whether liver, stomach and spleen located on patient’s right or left side  S  Largest lobe of the liver on the RIGHT  Spleen and stomach on the LEFT  I  Largest lobe of the liver on the LEFT  Spleen and stomach on the RIGHT  A  Not fit either category Visceral Situs Thoraco- abdominal Situs Atrial Situs VISCERAL SITUS { X , _ , _ }Visceroatrial Situs
  25. 25. Largest hepatic lobe on right side, spleen and stomach on the left side, normal configuration Left-sided liver, right-sided stomach and multiple right-sided splenic tissue RadioGraphics 2013; 33:E33–E46
  26. 26. Useful for identifying the morphologic RA Pulmonary sideness usually reflects atrial sideness  S  Morphologic (trilobed) right lung and largest lobe of liver on the RIGHT  I  Morphologic (bilobed) right lung and largest lobe of liver on the LEFT  A  Duplicate sideness or not fit either category Visceral Situs Thoraco- abdominal Situs Atrial Situs THORACOABDOMINAL SITUS { X , _ , _ }Visceroatrial Situs
  27. 27. Morphologic right lung  Trilobe  Presence of minor fissure  Main bronchus is above behind the PA (eparterial)  Upper lobe bronchus more proximal originate Morphologic left lung  Bilobe  Absent of minor fissure  Main bronchus is below the PA (hyparterial)  Upper lobe bronchus more distal take off THORACOABDOMINAL SITUS { X , _ , _ }Visceroatrial Situs
  28. 28. Netter FH, 2014
  29. 29. The characteristic early takeoff of the right upper lobe bronchus. The morphologic right atrium is usually found on the same side as the morphologic right bronchial tree. Normal central bronchial anatomy which can be used to help differentiate the morphologic right lung from the morphologic left lung.The right main stem bronchus (asterisk) is more vertically oriented with an early branch point (white arrow) RadioGraphics 2013; 33:E33–E46 Mazur W, 2013
  30. 30. Duplication of the morphologic left bronchial tree pattern, with no early takeoff of the upper lobe bronchus on the right side, and a hyparterial position of both main bronchi below the course of the main pulmonary arteries These findings are indicative of left isomerism, a setting in which the bronchial anatomy is unhelpful for determining right- or left-sideness of the morphologic right atrium. RadioGraphics 2013; 33:E33–E46
  31. 31. Identify the morphologic RA  S  Morphologic RA on the RIGHT  I  Morphologic RA on the LEFT  A  Cannot be determined  Atrial situs and thoracoabdominal situs usually concordant Visceral Situs Thoraco- abdominal Situs Atrial Situs ATRIAL SITUS { X , _ , _ }Visceroatrial Situs
  32. 32. ATRIAL SITUS Morphologic RA  Right atrial appendage is broad and blunt, trapezoidal shape  Pectinate muscles extend around the vestibule and reach toward AV valve  Crista terminalis and tenia sagittalis  Septal surface consists of superior and inferior limbic bands  Receive blood from supradiaphragmatic IVC (rule of venoatrial concordance)  Coronary sinus drains into RA via Thebesian valve { X , _ , _ }Visceroatrial Situs Neill C, 2006
  33. 33. ATRIAL SITUS Morphologic LA  Right atrial appendage is narrower, tubular, finger-like shape  Pectinate muscles not beyond the appendage  Receive blood from pulmonary veins { X , _ , _ }Visceroatrial Situs Neill C, 2006
  34. 34. ATRIAL SITUS { X , _ , _ }Visceroatrial Situs RadioGraphics 2013; 33:E33–E46
  35. 35. Normal anatomy of the left atrium and right atrium. The right atrial appendage (RAA) typically has a triangular shape, with a wider opening and larger pectinate muscles (arrows) than those of the left atrial appendage (LAA), which has a fingerlike shape. RadioGraphics 2007; 27:829–846 The right atrial appendage (RAA) is triangular with a wide opening, whereas the left atrial appendage (LAA) is narrow and fingerlike. RadioGraphics 2003; 23:S147–S165
  36. 36. Trapezoidal shape of the right atrial appendage with its blunt end and broad connection to the rest of the atrium Tubular left atrial appendage with its pointed end and narrow connection. RadioGraphics 2013; 33:E33–E46
  37. 37.  If any letter recorded as A situs ambiguus { A , _ , _ }  If ALL the letters recorded as S situs solitus { S , _ , _ }  If ALL the letters recorded as I situs inversus { I , _ , _ } Visceral Situs Thoraco- abdominal Situs Atrial Situs VISCEROATRIAL DESIGNATION { X , _ , _ }Visceroatrial Situs
  38. 38. SITUS SOLITUS { S , _ , _ }  Morphologic RA and liver on the RIGHT side  Morphologic LA, stomach and spleen on the LEFT side  Morphologic (trilobed) right lung with eparterial bronchus on the RIGHT side  Morphologic (bilobed) left lung with hyparterial bronchus on the LEFT side { X , _ , _ }Visceroatrial Situs RadioGraphics 2010; 30:397–411
  39. 39. SITUS INVERSUS { I , _ , _ }  Morphologic RA and liver on the LEFT side  Morphologic LA, stomach and spleen on the RIGHT side  Morphologic (trilobed) right lung with eparterial bronchus on the LEFT side  Morphologic (bilobed) left lung with hyparterial bronchus on the RIGHT side { X , _ , _ }Visceroatrial Situs RadioGraphics 2010; 30:397–411
  40. 40. SITUS AMBIGUUS (HETEROTAXY SYNDROME) { A , _ , _ }  Heterotaxy syndrome  With asplenia / Right isomerism / Bilateral right-sideness  With polysplenia / Left isomerism / Bilateral left-sideness { X , _ , _ }Visceroatrial Situs RadioGraphics 2010; 30:397–411 Right isomerism Left isomerism
  41. 41. With Polysplenia  Left isomerism  Bilateral bilobed lung, hyparterial bronchus with absent minor fissure  Bilateral morphologic LA  Interruption of IVC with azygos or hemiazygos continuation  Multiple spleens  Pulmonary veins drains into both RA and LA With Asplenia  Right isomerism  Bilateral trilobed lung, eparterial bronchus and bilateral minor fissures  Bilateral morphologic RA  Large symmetric, centrally located liver  Absent spleens  Frequent total anomaly of pulmonary venous return (TAPVR) SITUS AMBIGUUS (HETEROTAXY SYNDROME) { X , _ , _ }Visceroatrial Situs RadioGraphics 2010; 30:397–411
  42. 42. With Polysplenia With Asplenia SITUS AMBIGUUS (HETEROTAXY SYNDROME) { X , _ , _ }Visceroatrial Situs An interrupted suprarenal IVC with azygous or hemiazygous continuation. The abdominal aorta and IVC are classically located on opposite sides of the midline The ipsilateral position of the abdominal aorta and IVC RadioGraphics1999;19:837–852
  43. 43. RELATION OF CARDIAC POSITION TO CHD  Situs solitus with levocardia (normal)  CHD occurs 0.6-0.8%  Situs inversus with dextrocardia  CHD occurs 3-5%  Situs inversus with levocardia  Extremely rare variant  CHD occurs 100%  Situs ambiguous or heterotaxy  Highly incidence associated CHD  Discordant position of one or more of cardiac apex, stomach, and aortic arch position  Associated with extra-cardiac anomalies e.g, splenic abnormalities, biliary atresia, and intestinal malrotation { X , _ , _ }Visceroatrial Situs
  44. 44. RadioGraphics 2010; 30:397–411
  45. 45. STEP 2 VENTRICULAR LOOP ORIENTATION { _ , X , _ }
  46. 46. VENTRICULAR LOOP DESIGNATION  Relation of morphologic RV as compared with the morphologic LV  Morphologic RV on RIGHT of morphologic LV: Dextro-loop { _ , D , _ }  Morphologic RV on LEFT of morphologic LV: Levo-loop { _ , L , _ }  If cannot be determined: { _ , X , _ } { _ , X , _ } Ventricular Loop Orientation D-loop { _ , D , _ } Normal L-loop { _ , L , _ } Neill C, 2006
  47. 47. VENTRICULAR INTRINSIC CHARACTERISTICS Morphologic RV  Coarse trabeculae  Presence of apical moderator band  Papillary muscles attached to both the interventricular septum and the free wall  Tricuspid AV valve  Separation of inlet (tricuspid) and outlet (pulmonary) valves by muscular ridge (crista supraventricularis)  Saddle-shaped { _ , X , _ } Ventricular Loop Orientation Neill C, 2006
  48. 48. Morphologic right ventricle (RV), which is characterized by coarse trabeculae and a muscular crest, the crista supraventricularis (arrowhead), between the tricuspid valve (TV) and the pulmonary valve (PV). RadioGraphics 2007; 27:829–846 A muscular structure (arrowheads) between the tricuspid valve (TV) and the pulmonary valve (PV).The right ventricle shows coarse trabeculae. RadioGraphics 2003; 23:S147–S165
  49. 49. Moderator band (arrow) traversing the apex of a cardiac chamber and extending from the base of the papillary muscle to the septal wall, helps identify the morphologic right ventricle. RadioGraphics 2013; 33:E33–E46
  50. 50. VENTRICULAR INTRINSIC CHARACTERISTICS Morphologic LV  Thin and delicate trabeculae  Smooth septal surface  Papillary muscles attached only to the free wall  Bicuspid AV valve  Complete continuity of fibrous tissue between inlet (mitral) and outlet (aortic) valves (mitroaortic fibrous continuity) { _ , X , _ } Ventricular Loop Orientation Neill C, 2006
  51. 51. Left ventricular inflow and outflow tract shows normal anatomy of the morphologic left ventricle with fine trabeculae, the anterolateral and posteromedial papillary muscles, and fibrous continuity (arrowhead) between the aortic valve (AV) and the mitral valve (MV). RadioGraphics 2007; 27:829–846 RadioGraphics 2003; 23:S147–S165 Fibrous continuity (arrowhead) between the mitral valve (MV) and the aortic valve (AV).The left ventricle shows fine trabeculae.
  52. 52. A moderator band (arrowhead) and a papillary muscle (arrow) attached to the interventricular septum, findings characteristic of the morphologic RV. Because this chamber is positioned leftward of the left ventricle, a position indicative of an L-loop, the letter L is assigned, thus “{_, L, _}.” LV RV RadioGraphics 2013; 33:E33–E46
  53. 53. A papillary muscle (arrow) attached to the septal wall, a feature that helps identify this chamber as the RV. Because the chamber is positioned rightward of the left ventricle, a position indicative of d-loop, the letter D is assigned, thus {_, D, _}” LV RV RadioGraphics 2013; 33:E33–E46
  54. 54. RV RV RV RV LV LV LV LV RadioGraphics 2010; 30:397–411
  55. 55. RadioGraphics 2013; 33:E33–E46
  56. 56. HAND RULE AND LOOP RULE  In complicated case that orientation may be difficult to discern because spiral configuration does not fit right-left plane easily  E.g. superoinferior ventricles, crisscross AV alignments, single ventricle  Hand rule  Loop rule { _ , X , _ } Ventricular Loop Orientation
  57. 57. HAND RULE  Identify the RV  Imagine approach the heart from anterior direction  Placing your hand inside the RV with palm against interventricular septum, the thumb in RVIT (AV valve) and fingers in RVOT  Accomplish with Right hand >> Rightward orientation, D-loop { _ , D , _ }  Accomplish with Left hand >> Leftward orientation, L-loop { _ , L , _ } { _ , X , _ } Ventricular Loop Orientation D-loop { _ , D , _ } Normal L-loop { _ , L , _ }
  58. 58. While viewing the heart from the anterior to the posterior direction, the viewer imagines placing a hand into the morphologic right ventricle with the palm against the interventricular septum, the thumb in the RVIT, and the fingers in the RVOT. If this exercise can be performed with the right hand, a d-loop is present; if it can be performed only with the left hand, an l-loop is present. RVIT RVOT Septum RadioGraphics 2013; 33:E33–E46
  59. 59. LOOP RULE  Position and relation of great vessles are predictive of the loop orientation  Right-sided aortic valve  RV located rightward of LV >> D-loop { _ , D , _ }  Left-sided aortic valve  RV located leftward of LV >> L-loop { _ , L , _ } { _ , X , _ } Ventricular Loop Orientation CT scan shows the aortic valve with right (R), left (L), and noncoronary (N) cusps and the pulmonary valve with right (R), left (L), and anterior (A) cusps. Pulmonary Aortic RadioGraphics 2003; 23:S147–S165
  60. 60. STEP 3 POSITION AND RELATION OF THE GREATVESSELS { _ , _ , X }
  61. 61. RELATION OF THE GREATVESSELS  Aorta and main PA are classified according to their position at the level of aortic and pulmonary valves  Aorta supplies at least one coronary artery  Main PA usually yields right and left PA  Normal configuration:Aortic lies posterior and rightward of the PA  Conus anatomy may be helpful { _ , _ , X } Position and Relation of the GreatVessels Posterior Anterior ~150° Neill C, 2006
  62. 62. Normal configuration of the great vessels.The aorta (A) has a normal posterior relation and normal rightward position relative to the MPA (P), a configuration designated as {_, _, S} CT scan shows the aortic valve with right (R), left (L), and noncoronary (N) cusps and the pulmonary valve with right (R), left (L), and anterior (A) cusps. Pulmonary Aortic RadioGraphics 2013; 33:E33–E46 RadioGraphics 2003; 23:S147–S165
  63. 63. DESIGNATION  Aorta is posterior to and rightward of main PA (normal) >> situs solitus { _ , _ , S }  Aorta is posterior to but inverted leftward of main PA >> situs inversus { _ , _ , I }  Transposition: usually applies when aorta arises from the RV and main PA arises from LV  Aorta is anterior to and rightward of main PA >> D-transposition { _ , _ , D-TGV }  Aorta is anterior to and leftward of main PA >> L-transposition { _ , _ , L-TGV } { _ , _ , X } Position and Relation of the GreatVessels RadioGraphics 2013; 33:E33–E46
  64. 64. Inversion of the great vessels. Situs inversus of the great vessels at the level of the valves.The aorta has a normal posterior relation to the MPA but is positioned at its left, a mirror image of the normal configuration, designated as {_, _, I}. RadioGraphics 2013; 33:E33–E46
  65. 65. DESIGNATION  Malposition: both arteries originate from same ventricles or are overriding e.g. in double-outlet left or right ventricle (DORV or DOLV)  Aorta is rightward of main PA >> D-malposition { _ , _ , D-MGV }  Aorta is leftward of main PA >> D-malposition { _ , _ , L-MGV } { _ , _ , X } Position and Relation of the GreatVessels RadioGraphics 2013; 33:E33–E46
  66. 66. RadioGraphics 2010; 30:397–411
  67. 67. CONOTRUNCAL ANOMALIES  During development, muscle under aortic valve resorbed, whereas subpulmonary muscle (conus) grows  Conal anatomy  Subpulmonary conus (normal)  Subaortic conus  Bilateral conus  Bilaterally absent conus  Presence of conus under semilunar valve usually indicates that vessel originate from RV (exception may occurred) { _ , _ , X } Position and Relation of the GreatVessels
  68. 68. CONOTRUNCAL ANOMALIES  Double outlet cardiomyopathies: the great vessels are side-by-side (MGV)  Bilateral conus is seen in double-outlet RV (DORV) without atrioventricular fibrous continuity  Bilaterally absent conus is seen in double-outlet LV (DOLV) with atrioventricular fibrous continuity { _ , _ , X } Position and Relation of the GreatVessels
  69. 69. CONOTRUNCAL ANOMALIES  Subaortic conus without subpulmonary conus is found in case of D- or L-TGV  Aorta which lack atrioventricular (mitroaortic) fibrous continuity is anterior to the pulmonary valve with atrioventricular valve continuity  Transposition usually applies when aorta arises from RV and main pulmonary artery arises from LV { _ , _ , X } Position and Relation of the GreatVessels
  70. 70. CONOTRUNCAL ANOMALIES  D-transposition { S , D , D-TGV }  Complete (uncorrected) TGA  Normal position of atrium and ventricle, A-V concordance, anomaly only at the conus level  Right-sided aorta anteriorly positioned arises from RV with subaortic conus  Left-sided PA posteriorly positioned arises from LV with mitropulmonary fibrous continuity { _ , _ , X } Position and Relation of the GreatVessels Ao RV LV PA MazurW,2013 Right Atrium Right Ventricle Aorta Left Atrium Left Ventricle Pulmonary artery
  71. 71. CONOTRUNCAL ANOMALIES  L-transposition { S , L , L-TGV }  Congenitally (physiologically) corrected transposition  Abnormal positioning of great vessels and inverted ventricular position (L-loop)  Associated with A-V discordance { _ , _ , X } Position and Relation of the GreatVessels Ao LV RV PA MazurW,2013
  72. 72.  L-transposition { S , L , L-TGV }  Left-sided RV connected to LA and anteriorly left-sided aorta (with subaortic conus)  Right-sided LV connected to RA and right-sided PA (with mitropulmonary fibrous continuity) Ao LV RV PA MazurW,2013 Right Atrium Left Ventricle Pulmonary artery Left Atrium Right Ventricle Aorta Atrioventricular discordance Ventriculoarterial discordance CONOTRUNCAL ANOMALIES { _ , _ , X } Position and Relation of the GreatVessels
  73. 73. ASSESSMENT OF CONNECTING SEGMENTS
  74. 74. Step 1 Visceroatrial situs Step 2 Ventricular loop orientation Step 3 Position and relation of the Great vessels Segments: Connections: Atrioventricular junction Ventriculoarterial junction Put it all together
  75. 75. ATRIOVENTRICULAR (A-V) CONNECTIONS 5 types of atrioventricular connection 1. Concordant  Ventricle appropriate relative to visceroatrial situs  Morphologic RA drains into morphologic RV, morphologic LA drains into morphologic LV 2. Discordant  Ventricle inappropriate relative to visceroatrial situs  Morphologic RA drains into morphologic LV, morphologic LA drains into morphologic RV  E.g., transposition of great vessels Connecting Segments Concordant Discordant MazurW,2013
  76. 76. ATRIOVENTRICULAR (A-V) CONNECTIONS 3. Ambiguous  Visceroatrial situs ambiguus  Heterotaxy Connecting Segments MazurW,2013
  77. 77. ATRIOVENTRICULAR (A-V) CONNECTIONS 4. Double inlet  Single ventricle 5. Absent right or left connection  Dominant left or right ventricle Connecting Segments Right- sided atrium Left- sided atrium Right- sided atrium Left- sided atrium Right- sided atrium Left- sided atrium Double inletAbsent right connection Absent left connection MazurW,2013
  78. 78. VENTRICULOARTERIAL (V-A) CONNECTION Connecting Segments 4 types of atrioventricular connection 1. Concordant  Main PA arises from morphologic RV, aorta arises from morphologic LV 2. Discordant  Main PA arises from morphologic LV, aorta arises from morphologic RV  Synonymous with transposition of the great vessels Ao RV LV PA Ao RV LV PA Ao LV RV PA MazurW,2013
  79. 79. VENTRICULOARTERIAL (V-A) CONNECTION Connecting Segments 3. Double-outlet right ventricle (DORV)  The great vessels arise from RV 4. Double-outlet left ventricle (DOLV)  The great vessels arise from LV MazurW,2013
  80. 80. ASSOCIATED MALFORMATIONS  Importance for surgical approach and profound physiologic significance  Heart  Atrial and ventricular septal defects  Size of ventricles  Ventricular outflow tract stenosis  Great vessels  Hypoplastic or stenotic lesion  PDA  Coronary anomalies  SVC
  81. 81. EXAMPLE CASES FROM KCMH
  82. 82. CASE I  Step 1: Determine visceroatrial situs  Largest lobe of the liver on the RIGHT  Spleen and stomach on the LEFT Visceral Situs Thoraco- abdominal Situs Atrial Situs Record letter S KCMH
  83. 83. CASE I  Step 1: Determine visceroatrial situs Visceral Situs Thoraco- abdominal Situs Atrial Situs KCMH Eparterial bronchus Right Left Hyparterial bronchus PA PA
  84. 84. CASE I  Step 1: Determine visceroatrial situs  Morphologic (trilobed) right lung and largest lobe of liver on the RIGHT Record letter S Visceral Situs Thoraco- abdominal Situs Atrial Situs KCMH
  85. 85. CASE I  Step 1: Determine visceroatrial situs Record letter S Visceral Situs Thoraco- abdominal Situs Atrial Situs Trapezoid-shape, broad and blunt with a wider opening Fingerlike and narrowRAA LAA KCMH
  86. 86. CASE I  If ALL the letters recorded as S situs solitus { S , _ , _ } Visceral Situs Thoraco- abdominal Situs Atrial Situs S S S { S , _ , _ }
  87. 87. CASE I  Step 2: Determine ventricular loop orientation Papillary muscle Coarse trabeculation Thin trabeculation LV RV LV RV  Morphologic RV on LEFT of morphologic LV: Levo-loop { _ , L , _ } { S , L , _ } KCMH
  88. 88. CASE I  Step 3: Position and Relation of the GreatVessels Aorta is anterior to and leftward of main PA L-transposition { _ , _ , L-TGV } { S , L , L-TGV } Pulmonary Aortic KCMH
  89. 89. CASE I  Determine connecting segments { S , L , L-TGV } Right Atrium Left Ventricle Pulmonary artery Left Atrium Right Ventricle Aorta Atrioventricular discordance Ventriculoarterial discordance Ao LV RV PA MazurW,2013
  90. 90. CASE I  Associated anomalies  Membranous ventricular septal aneurysm  Patent foramen ovale  Pulmonary hypertension { S , L , L-TGV } Ventricular septal aneurysm Patent foramen ovale KCMH
  91. 91. CASE I  Findings:  Situs solitus with levocardia  Levo-transposition of the great vessels  Atrio-ventricular and ventriculo-arterial discordance  Diagnosis: Congenitally corrected L-TGA { S , L , L-TGV } Ao LV RV PA MazurW,2013
  92. 92. CASE 2  Step 1: Determine visceroatrial situs  Largest lobe of the liver on the LEFT  Spleen and stomach on the RIGHT Visceral Situs Thoraco- abdominal Situs Atrial Situs Record letter L KCMH
  93. 93. CASE 2  Step 1: Determine visceroatrial situs  Bilateral morphologic bilobed lungs Bilateral hyparterial bronchus  Situs ambiguus with LEFT isomerism (polysplenia) Record letter A Visceral Situs Thoraco- abdominal Situs Atrial Situs KCMH PA PA
  94. 94. CASE 2  Step 1: Determine visceroatrial situs Record letter A Visceral Situs Thoraco- abdominal Situs Atrial Situs  One large dilated single common atrium  Broad based atrial appendage on right side Broad and blunt, trapezoidal shape KCMH
  95. 95. CASE 2  If any letter recorded as A situs ambiguus { A , _ , _ } Visceral Situs Thoraco- abdominal Situs Atrial Situs S A A { A , _ , _ }
  96. 96. CASE 2  Step 2: Determine ventricular loop orientation Coarse trabeculation  Single ventricle with coarse trabeculation and moderator band >> morphologic RV  Right-sided aortic valve (Loop Rule) >> Dextro-loop { _ , D , _ } { A , D , _ } Subpulmonic conus KCMH Pulmonary Aortic
  97. 97. PulmonaryAortic CASE 2  Step 3: Position and Relation of the GreatVessels  The great vessels are along the same coronal plane, but aorta is rightward of main PA >> Dextro-malposition { _ , _ , D-MGV }  Aorta and pulmonary trunk arises from single ventricle  Malposition: both arteries originate from same ventricles { A , L , D-MGV } KCMH
  98. 98. CASE 2  Determine connecting segments { A , L , D-MGV } Common Right Atrium Single Right Ventricle Pulmonary artery Aorta The great vessels arise from RV DORV Absent Left connection Common A-V valve
  99. 99. CASE 2  Associated anomalies  Left-sided SVC  Interrupted IVC with azygos continuation  Dilated hemiazygos and azygos drains into left- sided SVC { A , L , D-MGV } Absent intrahepatic IVC Dilated hemiazygos v Left-sided SVC Dilated hemiazygos v KCMH
  100. 100. CASE 2  Associated anomalies  Left-sided SVC and pulmonary veins draining into common atrium  Hepatic veins draining into common atrium { A , L , D-MGV } KCMH
  101. 101. CASE 2  Diagnosis:  Situs ambiguus with left isomerism  Dilated common atrium, hypertrophic single RV  Common atrioventricular canal  Double outlet RV (DORV)  Left-sided SVC, and interrupted IVC with azygos continuation { A , L , D-MGV }
  102. 102. SUMMARY OF SEGMENTAL APPROACH
  103. 103. Determining whether liver, stomach and spleen located on patient’s right or left side  S  Largest lobe of the liver on the RIGHT  Spleen and stomach on the LEFT  I  Largest lobe of the liver on the LEFT  Spleen and stomach on the RIGHT  A  Not fit either category Visceral Situs Thoraco- abdominal Situs Atrial Situs VISCERAL SITUS { X , _ , _ }Step 1:Visceroatrial Situs Record letter
  104. 104. Useful for identifying the morphologic RA Pulmonary sideness usually reflects atrial sideness  S  Morphologic (trilobed) right lung and largest lobe of liver on the RIGHT  I  Morphologic (bilobed) right lung and largest lobe of liver on the LEFT  A  Duplicate sideness or not fit either category Visceral Situs Thoraco- abdominal Situs Atrial Situs THORACOABDOMINAL SITUS { X , _ , _ }Step 1:Visceroatrial Situs Record letter
  105. 105. Morphologic right lung  Trilobe  Presence of minor fissure  Main bronchus is above behind the PA (eparterial)  Upper lobe bronchus more proximal originate Morphologic left lung  Bilobe  Absent of minor fissure  Main bronchus is below the PA (hyparterial)  Upper lobe bronchus more distal take off THORACOABDOMINAL SITUS { X , _ , _ }Step 1:Visceroatrial Situs
  106. 106. Identify the morphologic RA  S  Morphologic RA on the RIGHT  I  Morphologic RA on the LEFT  A  Cannot be determined  Atrial situs and thoracoabdominal situs usually concordant Visceral Situs Thoraco- abdominal Situs Atrial Situs ATRIAL SITUS { X , _ , _ }Step 1:Visceroatrial Situs Record letter
  107. 107. ATRIAL SITUS { X , _ , _ }Step 1:Visceroatrial Situs RadioGraphics 2013; 33:E33–E46
  108. 108.  If any letter recorded as A situs ambiguus { A , _ , _ }  If ALL the letters recorded as S situs solitus { S , _ , _ }  If ALL the letters recorded as I situs inversus { I , _ , _ } Visceral Situs Thoraco- abdominal Situs Atrial Situs VISCEROATRIAL DESIGNATION { X , _ , _ }Step 1:Visceroatrial Situs
  109. 109. VENTRICULAR LOOP DESIGNATION Determine which ventricle is the morphologic RV and which is the morphologic LV  Morphologic RV on RIGHT of morphologic LV: { _ , D , _ } Dextro-loop  Morphologic RV on LEFT of morphologic LV: { _ , L , _ } Levo-loop  If cannot be determined: { _ , X , _ }  Hand rules  Loop rules { _ , X , _ } Step 2:Ventricular Loop Orientation
  110. 110. RadioGraphics 2013; 33:E33–E46
  111. 111. DESIGNATION Determine the position and relation of the aorta and the main PA at the level of the aortic and pulmonary valves  Aorta is posterior to and rightward of main PA situs solitus { _ , _ , S }  Aorta is posterior to and leftward of main PA situs inversus { _ , _ , I }  Aorta is anterior to and rightward of main PA D-transposition { _ , _ , D-TGV }  Aorta is anterior to and leftward of main PA L-transposition { _ , _ , L-TGV } { _ , _ , X } Step 3: Position and Relation of the GreatVessels RadioGraphics 2013; 33:E33–E46
  112. 112. DESIGNATION  The great vessels are along the same coronal plane, but  Aorta is rightward of main PA Dextro-malposition { _ , _ , D-MGV }  Aorta is leftward of main PA Levo-malposition { _ , _ , L-MGV } { _ , _ , X } Step 3: Position and Relation of the GreatVessels RadioGraphics 2013; 33:E33–E46
  113. 113. RadioGraphics 2013; 33:E33–E46
  114. 114. ATRIOVENTRICULAR CONNECTIONS 5 types of atrioventricular connection 1. Concordant  Ventricle appropriate relative to visceroatrial situs  Morphologic RA drains into morphologic RV, morphologic LA drains into morphologic LV 2. Discordant  Ventricle inappropriate relative to visceroatrial situs  Morphologic RA drains into morphologic LV, morphologic LA drains into morphologic RV  E.g., transposition of great vessels 3. Ambiguous  Visceroatrial situs ambiguus  Heterotaxy 4. Double inlet  Single ventricle 5. Absent right or left connection  Dominant left or right ventricle Connecting Segments
  115. 115. VENTRICULOARTERIAL CONNECTION Connecting Segments 4 types of atrioventricular connection 1. Concordant  Main PA arises from morphologic RV, aorta arises from morphologic LV 2. Discordant  Main PA arises from morphologic LV, aorta arises from morphologic RV  Synonymous with transposition of the great vessels 3. Double-outlet right ventricle (DORV)  The great vessels arise from RV 4. Double-outlet left ventricle (DOLV)  The great vessels arise from LV
  116. 116. MazurW,2013
  117. 117. REFERENCES  Applegate KE, et al. Situs Revisited: Imaging of the Heterotaxy Syndrome. RadioGraphics. 1999; 19:837– 852. doi:10.1148/radiographics.19.4.g99jl31837  Fulcher AS,Turner MA.Abdominal Manifestations of Situs Anomalies in Adults. RadioGraphics. 2002; 22:1439–1456.doi:10.1148/rg.226025016  Goo HW, et al. CT of Congenital Heart Disease: Normal Anatomy andTypical Pathologic Conditions. RadioGraphics.2003; 23:S147–S165.doi:10.1148/rg.23si035501  Leschka S, et al. Pre- and Postoperative Evaluation of Congenital Heart Disease in Children and Adults with 64-Section CT. RadioGraphics 2007; 27:829–846. doi:10.1148/rg.273065713  Lapierre C, et al. Segmental Approach to Imaging of Congenital Heart Disease. RadioGraphics. 2010; 30:397–411. doi:10.1148/rg.302095112  Schallert EK, et al. Describing Congenital Heart Disease by UsingThree-Part Segmental Notation. RadioGraphics.2013; 33:E33–E46. doi:10.1148/rg.332125086  Neill C, et al.The Segmental Approach to Congenital Heart Disease. In: Nichols DG, editors. Critical Heart Disease in Infants and Children. 2nd ed. Philadelphia: Mosby Elsevier; 2006.  MazurW, et al. CT Atlas of Adult Congenital Heart Disease. London: Springer-Verlag, 2013.  Moore KL, et al. Cardiovascular System. In: Moore KL, PersaudTVN,Torchia MG.The Developing Human. 10th ed. Philadelphia: Elsevier; 2016.

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