Radiographic approach to cardiac enlargement by Dr. Neelam Maharjan

1. Radiographic approach to
cardiac enlargement
Dr. Neelam Maharjan
FCPS Resident,
Bir hospital,NAMS

2. Anatomy
• Heart is pyramidal in shape and lies obliquely in the anterior
mediastinum immediately posterior to the sternum and closely
related to the central portion of the diaphragm.
• The left atrium forms base or posterior part with four pulmonary
veins draining into it.
• The right atrium forms the right border with superior venacava
and inferior venacava draining into its upper and lower part.
• The apex and left border is formed by left ventricle. The right
ventricle forms the anterior part.
• The inferior or diaphragmatic part is formed by both ventricles
anteriorly and a small part of right atrium posteriorly.

4. Pericardium
• Closed sac consisting of parietal and visceral layers that
enclose a potential space which contains 20-25 ml of serous
fluid.
• Covers the heart and great vessels.
• Superior and inferior venacava and the pulmonary veins are
all enclosed within a single fold of pericardium,which
contain a recess known as oblique sinus.
• The outflow from the heart through the aorta and
pulmonary artery is enveloped separately and between the
major inflow and outflow vessels,there is a transverse
pericardial sinus.

5. Right atrium
-Triangular and broad based atrial
appendage with trabeculations.
-Superior and inferior venacava
drain into the smooth posterior
part.
-Coronary sinus drain into the
posterior wall between the
orifice of IVC and tricuspid valve.
-Crista terminalis separates atrial
appendage from smooth part.
-Interatrial septum bears an oval
depression in its lower part,
fossa ovalis, surrounded by
superior limbus.

6. Left atrium
• Smooth walled chamber which gives rise to a
narrow based and anteriorly pointing finger-
like left atrial appendages.
• Lies slightly higher than right atrium
• Receives opening of four pulmonary veins in
its posterior wall.

7. Right ventricle
• Roughly triangular and flattened from front to back.
• Its lower half normally touches the sternum on
lateral view.
• Wall measures 4-5 mm
• Interventricular septum curves towards the right
ventricle due to high pressure of LV
• Its inflow and outflow tract is separated by muscular
conus or infundibulum.
• The interior of right ventricle has irregular muscular
elevations called trabeculae carneae.

8. • The entrance to the RV is
tricuspid valve:has three
leaflets(anterior,inferior and
septal) each attached to
papillary muscles of
ventricles by chordae
tendinae.
• Pulmonary valves has three
semilunar cusps:right and
left anterior and a posterior
cusps.

9. Left ventricle
• Most muscular chamber, finely trabeculated ,
being circular in cross section
• Wall thickness of 1 cm in diastole
• Fills through mitral valve with two leaflets;
anterior and posterior attached to papillary
muscles of ventricle by chordae tendinae
• Outflow through aortic valve;three cusps:right
and left posterior and anterior.
• Above each cusp is a localised dilatation,k/a
sinuses of valsalva

10. • Coronary arteries and veins

11. Right coronary artery
-Arises from anterior sinus of valsalva, passes to
right in between pulmonary trunk and right
atrium to descend in the right AV groove as
the marginal artery.
-On inferior surface of the heart, it anastomoses
with the left coronary artery in the region of
the posterior interventricular groove.

12. Branches
• Conus artery to the pulmonary outflow tract
• Atrial and ventricular branches
• Branch to sinoatrial node
• Acute marginal artery,which run anteriorly to
supply the right ventricle
• Branch to atrioventricular node
• Posterior interventricular artery, supplies the
inferior surface of left ventricle and the posterior
two-thirds of the interventricular system.

13. Left coronary artery
• Arises from the left posterior sinus of valsalva,
passes behind and to the left of the
pulmonary trunk to reach to left AV groove.
• Bifurcates into left circumflex artery which
anastomose with the right coronary artery
and the anterior descending artery which
descends in the interventricular groove.

14. Branches
Anterior descending artery
• Septal branches
• Diagonal branches that run over anterolateral
wall of the left ventricle supplying it
Left circumflex artery
• Obtuse marginal branches, which supply the
lateral wall of the left ventricle
• Atrial branches

15. Coronary Veins

16. CHEST X-RAY
 commonest type of imaging examination of the
heart.
 cardiac size and contour can be clearly
demonstrated.
 evaluation of lung field: gives vital clues to cardiac
function.
 demonstrates additional features related to cardiac
disease which may include metallic or other
implants, calcifications or bony anomalies.

17. Technical Factors
• Conventional PA film:
– Positioning
– High KVp technique
– FFD- 6 feets( minimize cardiac
enlargement)
– Centering – at T7
– Short exposure time to reduce
motion artifact of heart
– End inspiration

18. Cardiac Silhouette
• The image of the heart and great vessels on
the chest radiograph is a two-dimensional
display of dynamic three dimensional
structures .
• The cardiovascular silhouette varies not only
with the abnormality but also with body
habitus, age, respiratory depth, cardiac cycle,
and position of the patient

19. • With good centring
two thirds of the
cardiac shadow lies to
the left of midline and
one-third to the right,
although this is quite
variable in normal
subjects.

20. Cardiac shape
Hyposthenics: long and narrow
Hypersthenics: transverse
Moderately built: oblique or globular in shape
Infants: Transverse or globular

21. Cardiac Silhouette
Cardiac contour
PA view
Right Heart Border
• Superior venacava
• Ascending aorta ( when
tortous)
• Right atrium
• inferior venacava
Left heart Borders
• Aortic Knuckle
• Pulmonary Bay
• Left Atrial appendage
• Left ventricle

22. PA view demonstrating cardiac silhouette

23. Lateral Projection
• Anteriorly
– Right atrial
appendage
– Right ventricle
• Posteriorly
– Left atrium
– Left ventricle

24. Heart Size on Chest Radiographs
• Assessment of
1. Transverse cardiac diameter
Females: 14.5 cm
Males: 15.5 cm
2. Transverse cardiothoracic ratio
Normal: 50% on a PA
55% in Asians and Africo-Carribeans
60% on AP and in children

25. • An increase in excess of 1.5 cm in the transverse
diameter on comparable serial films is significant.
• However, heart shadow is enlarged with:
1. Short FFD
2. On expiration
3. In supine
4. AP projection when the diaphragms are elevated

26. • The heart enlarges in two different
haemodynamic situations
– diastolic volume overload
• excessive volume of blood during its filling phase
– pump failure.

27. Generalized Cardiac Enlargement
• Global heart enlargement, with maintenance
of an otherwise normal cardiac contour,
usually is due to diffuse myocardial disease,
abnormal volume or pressure overload as a
consequence of valvular heart disease,
hyperthyroidism, hypothyroidism, and
anemia.
• Pericardial effusions also produce generalized
enlargement of the cardiac silhouette

28. Gross cardiomegaly
• Pericardial effusion
• Cardiomyopathy
• Multivalve disease
• Congenital heart disease notably Ebstein’s
anomaly
• Ischemic heart disease

29. Left atrial enlargement
• Posterior chamber without any part
forming silhouette of heart on PA view
• Forms the posterior superior silhouette of
heart on lateral projection
• The chamber is the most posterior
structure and abutts the left main
bronchus and oseophagus posteriorly

30. Left atrium
sits in middle of
heart posteriorly
Left atrium
forms no border of
normal heart in PA
view
LA
RA
LV
This inset from a CT scan of the chest shows how
RA and LV obscure LA from forming a heart
border on the frontal film.

31. Left atrial enlargement
Causes
• Volume loading – Mitral regurgitation, VSD,
PDA
• Pressure loading –Left ventricular failure,
Mitral stenosis, Mitral valve obstruction due
to tumor

32. • Causes of isolated left atrial enlargement:
1) Mitral valve stenosis caused by rheumatic
heart disease.
2)Left atrial myxoma
3) Cor triatriatum
Heart is normal sized with abnormal incorporation of Pulmonary venous
structure in to the left atrium with unnecessary fibromuscular
membranous sub-division through the atrial chamber => classic or cor
triatriatum sinister (x ray changes similar to mitral stenosis)
similar in RA k/a cor triatriatum dexter

34. Radiographic features
• Elevation of left pulmonary artery
• Elevation and narrowing of left main bronchus
• Double right heart border: by projection of distended right
ward margin of left atrium lying close to right atrial margin.
{3 grades I to III: double border, flushes with RA border and
overshoot RA and forms right heart border}
• The distance from the middle of the left atrial border on the
double heart shadow to middle of left main bronchus more
than 7cm

36. • Convex left atrial
appendage(third mogul
sign):normally the left
heart border just below
the pulmonary outflow
track should be flat or
slightly concave.

37. Left atrial enlargement
• elevate the left main bronchus
• splaying of the carina
• straightening of the left heart border below the left
main bronchus, then as a discrete bulge on the left
• Oesophageal indentation /displacement
Left atrial shadow does not touch the right whereas
vertical descent of right atrial touches the dome

39. Left ventricular enlargement
• Volume loading-AR,MR,PDA
• Pressure loading-HTN,AS
• Wall abnormalities-left ventricular aneurysm,
cardiomyopathy

40. Signs on Xray
• Rounding of the apex of the heart
• Elongation of the long axis of the left
ventricle - left and downwards
• In the lateral view, dilatation of the body of
the left ventricular cavity is recognized when
the shadow of the heart bulges behind the
IVC

41. • Obstruction to left ventricular emptying or
increased afterload, as caused by systemic
hypertension, aortic coarctation, or aortic valve
stenosis, leads to hypertrophy initially, with
rounding of the cardiac apex .
• Left ventricular dilatation with cardiac failure may
follow. Dilated cardiomyopathy, especially
ischemic cardiomyopathy, primarily enlarges the
left ventricle.

42. Left Ventricle
Left ventricle

44. LV enlargement
• Rigler’s measurement
A: >17 mm
• Rigler’s measurement
B: <7.5 mm or obscured
• Eyeler’s ratio: >0.42
RV enlargement
• Rigler’s measurement
A: 17 mm or less
• Rigler’s measurement
B: 7.5 mm or more
• Eyeler’s ratio: 0.42 or
less
• {Normal values} = in RV
enlargement

45. • Aortic valve regurgitation and mitral valve
regurgitation enlarge the left ventricle and are
associated with dilatation of the aorta and left atrium,
respectively.
• Left ventricular aneurysms, usually the result of a
previous myocardial infarction, occasionally result in a
localized bulge that projects beyond the normal
ventricular contour or an angulation of the left
ventricular contour
• In the absence of heart failure, left ventricular
hypertrophy must be massive before the heart shadow
enlarges.

46. Right atrial enlargement
• Secondary to right ventricular failure
• Volume loading-Tricuspid regurgitation, ASD,
VSD, Anomalous pulmonary venous return
• Pressure loading-Tricuspid stenosis, tricuspid
valve obstruction from tumor or thrombus

47. • Isolated right atrial enlargement is uncommon
and usually is due to tricuspid stenosis or right
atrial tumor.
• Right atrial dilatation associated with other
chamber enlargement, primarily right ventricular
enlargement, can be seen in several conditions,
such as tricuspid regurgitation, pulmonary
arterial hypertension, shunts to the right atrium,
and cardiomyopathies .

48. Selective Right Atrial Enlargement
• Enlarged and globular heart
• right heart border becomes
more convex
• protrudes to the right away
from the midline (>5-5.5cm ),
>3cm from right lat vertebra.

49. • There may be associated with dilatation of
SVC and IVC that causes widening of right
superior mediastinum and an additional
border in right cardiophrenic angle
• Fill in of the space between the sternum and
the front of the upper part of the cardiac
silhouette in the lateral radiograph

50. • Marked isolated right atrial enlargement
resulting in a “box-shaped” heart is seen in
Ebstein’s malformation of the tricuspid valve .
• This configuration of the heart is the result of
marked angulation at the superior vena caval-
right atrial junction as the right atrium
enlarges.

52. Right ventricular enlargement
• Volume loading-Tricuspid regurgitation,
pulmonary regurgitation, ASD, VSD,
Anomalous pulmonary venous drainage
• Pressure overload-Pulmonary HTN, Pulmonary
stenosis, Acute PE

53. Signs
• Area of contact between the front surface of the
heart and the sternum increases .
• The characteristic elevation of the apex of the heart .
• Dilatation of the right ventricle may cause tilting-up
and posterior displacement of the left ventricle if this
is normal in size.
• Selective right ventricular enlargement include a
large main pulmonary artery and abnormal
peripheral pulmonary arteries, which may be
increased, pruned, or decreased.

55. Pericardial effusion

56. • Narrow vascularpedicle
• Cardiomegalydirectly proportional to severityof
pericardial effusion
• Thisshadowhasarounded, globular appearancewith
NON particular chamberenlargement
• Cardiophrenicanglebecomemore andmore acute
• Oligaemicpulmonary vascularmarkings
• Markedchangein cardiacsilhouette in decubitus
posture

57. Pulmonary vasculature
• Pulmonary arteries and veins provide
information about the cardiovascular system
• Visualisation of their abnormalities can only be
achieved reliably with a technically good erect
PA chest film.
• Visualisations depend on the silhouette sign
• Underexposed film may make vessels appear
more prominent.

58. Main
Pulmonary
Artery

59. Normal Pulmonary vascular pattern
• Begins with main pulmonary artery which
forms convexity on the left mediastinal border
between the arch of aorta and the straight left
heart border.
• Divides into left and right pulmonary arteries,
which divide in an orderly manner and
gradually taper towards periphery.

60. • Left Pulmonary Artery continues as a branch
of main pulmonary artery before branching.
• Right pulmonary artery arises sharply from
the main pulmonary artery, passing rightwards
into the mediastinum. Descending branch of
RPA is identified on the lower border of right
hilum whose maximum diameter is 16 mm for
males and 15 mm for females.
• LPA and left hilum are 1 cm above the RPA

61. • Veins are wider, less well defined and branch
less often than the companion arteries.
• Located medial to companion arteries in the
upper zones, overlap each other in mid zone
and lateral to the artery in the lower zone.
• Pulmonary veins converge in to the left atrium
2-3 cm below the hilum.

62. • The lower lobe vessels are 2-3 times larger
than the upper lobe vessels.
• In erect chest radiography, vessels in 1st ICS
are <3mm in diameter and those just above
the diaphragm are upto 6 mm.

67. Abnormal pulmonary vascular patterns
Pulmonary arterial hypertension
Pulmonary venous hypertension
Pulmonary plethora
Pulmonary oligemia

68. Pulmonary arterial hypertension
Systolic pressure more than 30 mm Hg in the
presence of normal systemic pressure.
Causes:
Long standing L-R shunts
Intrinsic lung disease
Pulmonary thromboembolic disease.
Secondary to increase in pulmonary venous
pressure.

69. Features
 Increased convexity of the pulmonary artery on the
left heart border
 Increased diameter of descending RPA
 Discrepancy between central and peripheral vessels
 Cardiomegaly
 Calcification of MPA and proximal branches

70. Increased pressure
Increased flow
Main pulmonary
artery projects
beyond tangent

71. 16

73. Venous hypertension
• PVH is said to be present when the pulmonary
capillary wedge pressure exceeds the normal
range:8-12 mm of Hg.
• Causes:
• impairment to the forward flow of blood through
the left side of heart (mitral stenosis, impaired left
ventricular function)
• Stage 1: cephalisation of the blood flow (13-19 mm
of Hg)

74. RDPA >16

75. Stage 2: interstitial edema ,pleural effusion (19-
25mm Hg)
–Kerly lines, peribronchial cuffing
–Background haze
–Septal and interstitial oedema

76. Stage 3 : Alveolar oedema (>25)
Bat wing appearance

77. Signs of plethora
1 Presence of shunt vessels, end on vessels more than 2 times the diameter
of accompanying bronchus
2. Prominent upper and lower zone vessels .
3. En-face vessels below 10th posterior rib
4. Prominent vessels below the crest of diaphragm
5. RDPA diameter more than that of trachea
6. RDPA >16mm in diameter
7. >6 vessels in peripheral one third of lung
8. Prominent hilar vessels on lateral view
9. In infants and children, generalized mottling may be seen

79. Pulmonary Oligemia
Decreasedflow proximal to origin of main
pulmonary artery
Small pulmonary artery
Empty pulmonary bay
Pulmonary vesselssmall
Lunghypertranslucent
Lateral view shows diminution of hilar vessels

81. THANK YOU

82. References
1)Text book of Radiology and Imaging-David Sutton
2)Diagnostic radiology chest and cardiovascular
imaging-Berry
3) Anatomy for diagnostic imaging-Stephanie Ryan
3) Radiopedia and internet sources