A pictorial view of almost all features of achondroplasia in pre and post natal life. After seeing this presentation one will become able to comment on Achondroplasia

1. ROLE OF SONOGRAPHIC IMAGING
IN ACHONDROPLASIA
Dr. Muhammad Bin Zulfiqar
PGR IV FCPS Services Institute of Medical Sciences / Hospital
radiombz@gmail.com

2. AIMS
• To look for Antenatal US imaging in Achondroplasia.
• To differentiate between homozygous / heterozygous
achondroplasia
• Role of plain radiography , CT and MRI

4. ACHONDROPLASIA
• Rhizomelic micromelia associated with frontal bossing and low
nasal bridge.
• Types:
• Heterozygous—Compatible with life
• Homozygous—Incompatible with life

5. HETEROZYGOUS ACHONDROPLASIA
• Prototype of rhizomelic dwarfism
• Autosomal dominant I sporadic (80%) disease with quantitatively
defective endochondral bone formation
• Related to advanced paternal age
• Epiphyseal maturation +ossification unaffected

6. OB-US (DIAGNOSABLE >21-27TH
WEEK GA):
• Shortening of proximal long bones: femur length <99th percentile
between 21 and 27 weeks MA
• Increased BPD, HC, HC AC ratio
• Decreased FL BPD ratio
• Normal mineralization, no fractures
• Normal thorax + normal cardiothoracic ratio
• Three-pronged(= trident) hand= 2nd+ 3rd +4th finger of similarly
short length without completely approximating each other(=
PATHOGNOMONIC)

7. CASE—1
HETEROZYGOUS
ACHONDROPLASIA
Mrs. M., 34 years old, housewife, G7P5, with no consanguinity, was admitted at 33 weeks of
gestation to antenatal ward for evaluation of fetus in view of tense polyhydramnios.
Yuliya Burmagina, MD; Ekaterina Kaloyanova, MD. 20087-06-
16-21 Achondroplasia © Burmagina www.thefetus.net/

8. • Frontal Bossing
• Flattened Nasal Bridge

9. • Abnormal head shape: brachycephaly with starting
craniosynostosis.

10. • Characteristic profile and head shape
(prefrontal edema, frontal bossing,
typical appearance of nasal bridge
(midface hypoplasia) and short cranial
base).

11. • “Bell-shaped" trunk (narrow thorax and
distended abdomen), frontal bossing.
Note the polyhydramnios.

12. • Note the significant difference in circumferences of abdomen and
thorax (along with relative cardiomegaly)

13. • Normal kidney size and sonographic pattern (enabling better
differential diagnosis).

14. • Absence of polydactyly (helping to differentiate
the condition).

15. • Short femur length=58 mm, <5centile, fibula & tibia. Humerus
(=52 mm, < 2centile).

16. • Note shortened arm (ulna=51 mm, <5 centile).

17. • X-ray study few days after birth:
Narrow chest, shortened long
bones (no evidence of
platyspondyly).

18. CASE—2
HETEROZYGOUS
ACHONDROPLASIA
A 21-year-old G2P1 at 36 weeks of pregnancy of gestation. Her husband has some family
history of achondroplasia.

19. • 36 weeks of pregnancy; the image 1 shows a normal head
circumference corresponding to 36+3 weeks of pregnancy. The
image 2 shows a short fetal femur corresponding only to 26+3
weeks of pregnancy.

20. • 36 weeks of pregnancy; the images show short long bones of the
fetus corresponding to 27 weeks (humerus; image 3) and 30
weeks of pregnancy (tibia; image 4).

21. • 3D image of the fetal face with the low nasal bridge and midface hypoplasia.
• The images compare the prenatal 3D image and postnatal appearance of the baby.

22. •Radiography
•CT Scan
•MRI

23. HETEROZYGOUS ACHONDROPLASIA
SKULL
• Large calvarium with frontal bossing
• Depression of nasion
• Broad mandible
• Constricted basicranium + small foramen magnum:
• Communicating hydrocephalus caused by obstruction of basal
cisterns + aqueduct

24. • Image shows an enlarged
calvaria with a shortened
skull base and frontal
bossing. Note the midface
hypoplasia.

25. • Enlarged calvaria. Note the
enlarged mandible.

26. • Typical findings of skull base achondroplasia; Large skull vault with
small skull base, narrow foramen magnum, prominent
forehead, depressed nasal bridge, dilated suprasellar cistern, vertical
straight sinus and dilated supratentorial ventricular system with
normal 4th ventricle.

27. • There is evidence of stenosis of the foramen magnum.

28. • Achondroplasia. Sagittal section
of the cervical spine on a T2-
weighted magnetic resonance
image in a 6-year-old patient who
presented with a neurologic
deficit. This image shows
narrowing of the foramen
magnum at the C1 canal,
effacement of the subarachnoid
spaces at the cervicomedullary
junction, and abnormal intrinsic
cord signal intensity.

29. HETEROZYGOUS ACHONDROPLASIA
CHEST
• Anteroposterior narrowing of chest
• Short anteriorly flared concave ribs
• Squaring of inferior scapular margin

30. • Shortened ribs.

31. HETEROZYGOUS ACHONDROPLASIA
SPINE
• .Hypoplastic bullet / wedge-shaped vertebra:
• Rounded anterior beaking of vertebra in upper lumbar spine (DDx:
Hurler disease)
• Decreased vertebral height
• Scalloped posteriorly concave vertebral margin
• Scoliosis:
• Thoracolumbar angular kyphosis (gibbus)
• Exaggerated sacral lordosis

32. HETEROZYGOUS ACHONDROPLASIA
SPINE
• Stenosis of lumbar spine:
• Narrowing of interpedicular space due to laminar thickening
• Ventrodorsal narrowing of spine due to short pedicles
• Bulging / herniation of intervertebral disks
• Wide intervertebral foramina

34. • Image shows progressive narrowing of
the lumbar spinal canal, bullet-nose
vertebrae, Note the shortened ribs

35. • Image shows progressive reduction in
vertebral interpediculate distance in the
caudal direction.

36. • The spine is often affected in
achondroplasia. Features include
interpediculate narrowing and
thickened pedicles.

37. • Disk herniation is common. Changes
in the spine can result in stenosis of
the spinal canal, particularly in the
lumbar region.

38. • Image shows a decreased lumbar
interpedicular distance. Note the scoliosis.

39. • short pedicles
• posterior vertebral scalloping
• thoracolumbar kyphosis
• tombstone iliac wings

40. HETEROZYGOUS ACHONDROPLASIA
PELVIS
• Square flattened iliac bones = Tombstone configuration
• Champagne glass"-shaped pelvic inlet
• Lack of flaring of iliac wings
• Horizontal acetabula(= flat acetabular angle)
• Small sacrosciatic notch

41. • short pedicles
• posterior vertebral scalloping
• thoracolumbar kyphosis
• tombstone iliac wings

42. • Champagne-glass pelvis with
squared iliac wings, a narrow
sacroiliac notch, and a reduced
acetabular angle.

43. • Image shows progressive narrowing of
the interpediculate distance with a
champagne-glass pelvis. Note that the
legs are straight in infancy.

44. HETEROZYGOUS ACHONDROPLASIA
EXTREMITIES
• Predominantly rhizomelic micromelia of long bones (femur,
humerus):
• “Trumpet" appearance of long bones = shortening with
disproportionate metaphyseal flaring (actually normal width of
metaphysis)
• Short femoral necks
• Limb bowing

45. HETEROZYGOUS ACHONDROPLASIA
EXTREMITIES
• Ball-in-socket" epiphysis = broad V-shaped distal femoral
metaphysis in which epiphysis is incorporated
• High position of fibular head(= disproportionately long fibula)
• Short ulna with thick proximal + slender distal end
• Brachydactyly (short tubular bones of hand+ feet), especially short
proximal + middle phalanges

46. • Image shows inverted femoral
physis (inverted V
configuration), which
contributes to a waddling gait.

47. • Genu varum. Image shows
rhizomelic shortening of the
bilateral femurs with
metaphyseal flaring. The
bones are wide because of
unaffected appositional
growth.

48. • Image shows rhizomelic shortening of the
humerus with posterior bowing and an
incomplete glenoid fossa.

49. • Image shows posterior bowing of the
humerus, the principal cause of the loss of
elbow extension. Posterior dislocation of the
radial head may also contribute.

50. • Trident hands. Image shows widely opposed fingers of equal
length.

51. • Trident hands.

52. COMPLICATIONS OF
ACHONDROPLASIA
(1) Hydrocephalus + syringomyelia (small foramen magnum)
(2) Recurrent ear infection (poorly developed facial bones)
(3) Neurologic complications (compression of spinal cord, lower
brainstem, cauda equina, nerve roots): apnea and sudden death
(4) Crowded dentition+ malocclusion

53. HOMOZYGOUS
ACHONDROPLASIA
• Hereditary autosomal dominant disease with severe features of
achondroplasia (disproportionate limb shortening, more marked
proximally than distally)
• Risk: marriage of two achondroplasts to each other

54. HOMOZYGOUS
ACHONDROPLASIA
• Skull:
• Large cranium with short base + small face
• Flattened nose bridge
• Short ribs with flared ends
• Vertebra:
• Hypoplastic vertebral bodies
• Decreased interpedicular distance

55. HOMOZYGOUS
ACHONDROPLASIA
• Pelvis:
• Short squared innominate bones
• Flattened acetabular roof
• Small sciatic notch
• Limb Bones:
• Short limb bones with flared metaphyses
• Short, broad, widely spaced tubular bones of hand

56. INDICES DEPICTING FATAL
OUTCOME
• FL / AC ratio <0.16---Lethal outcome
• FL / AC ratio >0.16---Non lethal outcome
• Normal thoracic / abdominal circumference ratio is 0.89-1.0
• TC /AC ratio of < 0.8 is associated with Pulmonary hypoplasia and lethality.
Antenatal Detection of Skeletal Dysplasias Barbara V. Parilla, MD, Elizabeth A. Leeth, MS, Michelle P. Kambich, MS, Patricia Chilis, RDMS and Scott N.
MacGregor, DO . Division of Maternal-Fetal Medicine, , Northwestern University Medical School, Evanston, Illinois USA. J Ultrasound Med 22:255-258 • 0278-4297.
Johnson A, Callan NA, Bhutani VK, Colmorgen GH, Weiner S, Bolognese RJ. Ultrasonic ratio of fetal thoracic to abdominal circumference: an association with fetal
pulmonary hypoplasia. Am J Obstet Gynecol 1987; 157:764–769.

57. THORACIC CIRCUMFERENCE
• Preparation: Full bladder for TA imaging in first and second
trimester
• Method: excluding the skin and subcutaneous tissues at the level
of four chamber view of the heart.
• Normal thoracic / abdominal circumference ratio is
•0.89-1.0
• TC /AC ratio of < 0.8 is associated with Pulmonary hypoplasia
and lethality.
Johnson A, Callan NA, Bhutani VK, Colmorgen GH, Weiner S, Bolognese RJ. Ultrasonic ratio of fetal thoracic to abdominal circumference: an
association with fetal pulmonary hypoplasia. Am J Obstet Gynecol 1987; 157:764–769.

58. DD BETWEEN ACHONDROPLASIA
• At 26 weeks BPD age:
• Homozygous fetuses never had a femoral length that exceeded 34 mm.
(progressive decrease in relative femoral length in the second trimester)
• Heterozygous fetuses always had a femoral length that exceeded 34
mm.
• Fetal femoral growth curves therefore allows the distinction
between homozygous, heterozygous and unaffected fetus in the
second trimester.

59. Cases

60. • Right. US scan of a homozygous achondroplastic fetus at 17.0 weeks
gestational age shows a morphologically normal femur (cursors).
• Left. US scan of a different homozygous achondroplastic fetus at 34.0
weeks gestational age shows an obviously short and thick femur with
metaphyseal flaring (cursors).

61. • Short ribs with flared ends, hypoplastic vertebral bodies (platyspondyly),
flat acetabular roof and small sciatic notches favor Homozygous
Achondroplasia

62. CASE
ACHONDROPLASIA
19 years male

63. • short pedicles
• posterior vertebral scalloping
• thoracolumbar kyphosis
• tombstone iliac wings

64. • short pedicles
• posterior vertebral scalloping
• thoracolumbar kyphosis
• tombstone iliac wings

65. CASE
ACHONDROPLASIA
Three month old child

66. •
Foramen magnum stenosis with significant compression of the
cervico-medullary junction.

68. CASE
ACHONDROPLASIA
Two Years Female Child

70. CASE
ACHONDROPLASIA
Three month old child

72. CASE
ACHONDROPLASIA
50 years female

73. • Bilateral knee x-rays show metaphyseal flaring
typical of achondroplasia.

74. CASE
ACHONDROPLASIA
14 Years Male

75. • Rhizomelic dwarfism, with relatively
short femora
• Bilateral genu vara.
• Metaphyseal flaring, most evident at the
lower femora, giving trumpet bone type
appearance
• Relatively long fibulae.
• V shaped growth plates, most evident at
the upper tibiae

76. CASE
ACHONDROPLASIA
1 Years Male

77. • Shortened long
bones of the upper
and lower limbs
with metaphyseal
flaring.
• Anterior Flaring of
the ribs.
• Small pelvis (trident
pelvis).

78. • Shortened long bones of the upper and lower limbs with metaphyseal flaring.
• Anterior Flaring of the ribs.
• Small pelvis (trident pelvis).

79. • Typical findings of skull base achondroplasia; Large skull vault with
small skull base, narrow foramen magnum, prominent
forehead, depressed nasal bridge, dilated suprasellar cistern, vertical
straight sinus and dilated supratentorial ventricular system with
normal 4th ventricle.

80. CASE
ACHONDROPLASIA
3 Years Male

81. • stenosis of the foramen magnum with a large skull

82. • trident hands

83. • metaphyseal flaring giving a trumpet bone type
appearance
• the femora and humeri are particularly shortened
(rhizomelic shortening)
• the acetabular roof is horizontal, the iliac wings have a
tombstone appearance
• horizontal sacrum

84. • progressive decrease in interpedicular
distance in lumbar spine

85. Role of CT

86. • CI axial section images of the foramen magnum of four patients with
achondropbasia. (a) Four-month-old patient; (b) 8-monthold
• patient; (c) il-month-old patient; (d) 2-year-old patient. The contour of the
posterior two-thirds of the foramen magnum varies, whereas
• the anterior third maintains a constant and symmetric shape.

87. • The posterior margin of the foramen
magnum extends anteriorly (arrow) beyond
the posterior arch of C1 and impinges on
the posterior surface of the bower medulla
oblongata and the upper cervical cord.
• The posterior margin of the foramen
magnum protrudes inferiorly (arrow) and
extends ventral to the posterior arch of C-1,
further decreasing the AP diameter of the
spinal canal.

88. • Coronal reformatted CT image shows the thickened, deformed left lateral margin of
the foramen magnum (arrow) compressing the neural tissue. The subarachnoid space
was opacified with intrathecal metrizamide (arrowhead) (metrizamide was black on
the negative image display).
• The mid-sagittal view shows kinking and narrowing of an “hourglass deformity” of the
cord at the cervicomedullary junction (arrow) with a thin layer of CSF interposed
between the cervical cord and the posterior margin of the foramen magnum.

89. • MR sagittal image (0.5 1) of the craniocervical junction with SE
538/38 (repetition time m sec/echo time m sec): the margin of
the foramen magnum is not clearly defined.
• However, the brain stem cord outline is well delineated; note the
abnormal focal cord narrowing from C-i to C-2 bevel

90. CARDIAOTHORACIC AND
HC / AC RATIO
• HC / AC 1.207 at 14 week's but decreased slowly until 30 week's when the
ratio was 1.110 thereafter there was a rather sharp fall in the mean ratio 1.010
at 36 weeks and 0.967 at 40 weeks and then the variability decreases.

91. DD ELLIS VAN CREVALD SYNDROME

92. • Ellis-van Creveld (EVC) syndrome is a differential
diagnosis of short-limb dwarfisms. It is also known
as chondroectodermal dysplasia. This autosomal
recessive disease involves chromosome 4p16. The
hands demonstrate polydactyly in almost all
patients, whereas the feet demonstrate
polydactyly in only 10%. Note the broad hands
with short middle phalanges and hypoplastic
distal phalanges. The carpal bones are malformed,
with fusion of the capitate and hamate.
Extracarpal bones might also be present. The ends
of the ulna and radius are enlarged.

93. • Ellis-van Crevald (EVC) syndrome.
(See the previous image.)

94. • The knees of patients with Ellis-van
Creveld (EVC) syndrome develop a
genu valgus deformity, and the long
bones are short. Hypoplasia of the
proximal tibia is also present. (See
the previous 2 images.)

95. • The knees of patients with Ellis-van
Creveld (EVC) syndrome develop a
genu valgus deformity, and the long
bones are short. Hypoplasia of the
proximal tibia is also present. (See
the previous 3 images.)

96. • The thoracic cavity of this patient
with Ellis-van Creveld (EVC)
syndrome is small and narrow,
with short ribs. About 60% of
patients have cardiac anomalies,
and most patients ultimately die
from respiratory illness.

97. • In Ellis-van Creveld (EVC) syndrome, the
teeth are hypoplastic, as are the nails.
The teeth are small and cone shaped,
with irregular spacing. Other facial
anomalies include a partial harelip.

98. • Metaphyseal chondroplasia (Schmid type) is a
differential diagnosis of achondroplasia, with
metaphyseal flaring of the ulna and radius as well as
bowing of the shaft. Note no hand involvement with
metaphyseal chondroplasia, unlike achondroplasia.

99. • Metatrophic dwarfism II, or Kniest
syndrome, is a differential diagnosis.
Skeletal dysplasia results in short
limbs and a proportionally long trunk;
however, the head and face appear
normal. With time, severe
kyphoscoliosis produces marked
shortening of the trunk, which can
make body proportions deceiving.

100. CASE
ACHONDROPLASIA
TWO YEARS MALE

101. • The skull vault is enlarged,
with small skull base.
• There is exacerbation of the
lumbar-sacral angle and the
interpedicular distance
gradually diminishes in the
lumbar spine. The iliac wings
are vertical.
• The limbs demonstrate normal
density with marked
shortening of the long bones.

102. • The skull vault is enlarged, with small skull base.
• There is exacerbation of the lumbar-sacral angle and the interpedicular distance
gradually diminishes in the lumbar spine. The iliac wings are vertical.
• The limbs demonstrate normal density with marked shortening of the long bones.

103. • There is evidence of stenosis of the foramen magnum.

104. CASE
ACHONDROPLASIA

105. • There is a relatively large cranial
vault with small skull base. There
is a prominent forehead with
depressed nasal bridge. The
foramen magnum is narrowed,
and there is a cervicomedullary
kink. Relative elevation of the
brainstem gives rise to a large
suprasellar cistern and a
vertically-oriented straight sinus.

106. TAKE HOME MESSAGE
• Antenatal Diagnosis is possible with confident.
• Antenatal Differentiation between lethal and non lethal
dysplasia is possible.
• Radiography, CT and MRI are helpful in
• Postnatal workup
• to look for complications.

107. THANK YOU