Pediatric Radiology

M. Reither

10 Pediatric Radiology

Special Consideration of the Growing Skeleton and Normal Variants

Epiphyseal Ossification of the Proximal Humerus

Ossification Pattern

Newborns: Ossification center rarely present, occasionally a faint calcific rim

Fourth to eighth month: Medial ossification center along the fossa

First to second year: Lateral ossification center in the major tuberosity

Third to fourth year: Ossification center in the minor tuberosity

Fifth to eighth year: Fusion of the tubercular ossification centers

Thirteen to fourteenth year: Fusion of the tubercular ossification centers with the proximal humeral epiphysis

Twentieth year: Osseous connection of the humeral epiphysis with the humeral diaphysis (Fig. 10.1).

Specific Findings

Epiphyseal plate resembles a pitched roof; differential diagnosis (DD): epiphyseal fracture (rare)

Crescentic vacuum phenomenon with the arms elevated and pulled: “True” joint space between glenoid and cartilage of the humeral epiphysis

Fig. 10.1 Diagram of the epiphyseal ossifications at the proximal humerus

a Fourth to eighth month

b First to second year

c Fifth to eighth year

Apophyseal Ossification of the Shoulder

Ossification Pattern

First year: Apophyseal ossification center in the coracoid process:

– Isolated until the 15th-16th year

– Occasional ossification center at the tip of the coracoid (Fig. 10.2)

Fifteenth to eighteenth year: Two to three or even more ossification centers in the lateral end of the acromion

Around the twentieth year: Fusion of the apophyseal ossification centers with the scapular spine

Sixteenth to eighteenth year: Apophyseal ossification centers at the superior and inferior angle of the scapula

Specific Findings

Double contour of the intertubercular groove; DD: Neonatal periosteal reaction, nonossifying osseous fibroma (NOF; Fig. 10.3).

Fig. 10.2 Apophyseal ossification center in the coracoid process (arrow)

Fig. 10.3 Neonatal humerus

Double contour of the intertubercular groove at the proximal humerus in the newborn (arrows).

Configuration of the Medial Clavicular End

First decade of life: Mushroom-like, smooth, or torn contours

Second decade of life: Cup-like, possibly irregularly outlined

Thirteenth to fourteenth year: Appearance of the medial epiphysis

At the end of the second decade of life: Fusion of the ossification center with the clavicle

“Ligament grooves” at the medial end of the clavicle caused by impression of the costoclavicular ligament (Fig. 10.4)

Fig. 10.4 “Ligamentous groove” (BG) at the medial end of both clavicles

Impression of the costoclavicular ligament as a linear radiolucency extending craniolaterally to caudalmedially. Incidental finding of a joint (arrows) forming between clavicle and coracoid process (clinically irrelevant anomaly).

Diagnostic Guidelines for Variations of the Growing Skeleton

1 CR (method of choice)

AP projection (comparison with contralateral side)

2 US (supplementary method)

Occasionally the only suitable method, for example, for evaluation of the humeral epiphysis

Therapeutic Principles

Conservative

For minor findings, physical therapy

Surgical

Distal displacement of the scapula (Green, Woodward) in the third to seventh year

Malformations

Congenital High Position of the Shoulder (Sprengel Deformity)

Pathology

Fifth week: Primordial scapula in the lower cervical region

Tenth week: Descent of the scapula to posterior chest wall

If interrupted, “congenital undescended scapula”

Usually unilateral

Scapula wide and shortened

Omovertebral bone: Fibrous, cartilaginous, or osseous connection between cervical spine and scapula

Hook-shaped curvature of the mediosuperior angle

Combination with muscle anomaly

In about 70% of cases, associated anomaly of the vertebrae and ribs (Klippel-Feil syndrome); spinal canal pathologies: diastematomyelia, syringomyelia

Clinical Findings

Asymmetry of the shoulder contour

Restricted mobility (abduction)

Diagnostic Evaluation

(→ Method of choice)

Recommended views

Standard projections:

– Anteroposterior (AP) projection of the shoulder joint

Special projection:

– Oblique projection: omovertebral bone

(→ Supplementary method)

Indications

Associated malformations of the spine and bony thorax

Therapeutic Principles

Surgical

Indications:

Pain

Functional impairment

Cosmetic disfiguration

Congenital Clavicular Pseudarthrosis

Pathology

Failed fusion of the clavicular ossification centers

Intrauterine fracture

Erosion: Pressure by the subclavian artery

Clinical Findings

Congenital

Often only discovered in the fourth to sixth year

Usually unilateral

Predominantly on the right

Medial fragment elevated

Lateral fragment pulled down by the weight of the arm

Cosmetic disfiguration

Shoulder function usually not impaired

Rarely painful

Diagnostic Evaluation

Recommended views

AP projection of the shoulder

Findings

Interrupted contour of the clavicular shaft

Clubbing of the ends of the fragments

Fibrous connection (Fig. 10.5)

Fig. 10.5 Congenital clavicular pseudarthrosis

Break in the lateral third of the clavicular shaft with terminal clubbing of the clavicle (arrows), with interposed fibrous bridging (B).

Shoulder Deformities in Osteochondrodysplasias

Cleidocranial Dysplasia

Pathology

Generalized skeletal disease

Defect formation

Impaired ossification

Autosomal dominant inheritance

Numerous phenotypic variations

Clinical Findings

Skull, thorax, and pelvis primarily involved

Bell-shaped thorax

Drooping shoulders

No palpable or visible normal clavicle

Hypermotility of the shoulder girdle

Shoulders can touch each other anteriorly

Associated pectus excavatum

Diastatic sagittal suture

Major and minor fontanelle wide open

Short terminal phalanges

Brachymesophalangy

Impaired dentition

Foot deformities

Abnormal gait

Lower limit of body height

Normal life expectancy

Habitual dislocation of shoulder, hip, and radial head

Vertebral deformities

Possibly maternal dystocia

Diagnostic Evaluation

Recommended views

AP shoulder girdle

AP pelvis

Skull in two projections

AP hand and foot

Lateral spine

Findings

AP shoulder girdle:

– Complete or partial absence of the clavicle

– Thin, short, inferiorly deviated ribs

– Small hypoplastic scapulae

– Narrow tubular bones

AP pelvis:

– Delayed ossification

– Hypoplastic iliac wings and pubic bones

– Wide cartilaginous pubic symphysis

– Wide sacroiliac (SI) joint spaces

– Wide acetabular Y-cartilage

– Valgus deformity of the femoral neck

– Narrow tubular bones

Skull in two projections:

– Delayed ossification of the calvarial ossification centers

– Numerous intercalary bones (“wormian bones”)

AP hand and foot:

– Pseudoepiphysis

Lateral spine:

– Extended persistence of biconvex vertebral bodies (Figs. 10.6, 10.7)

Goals of Imaging

“Minimal bone program”:

Lateral skull

Lateral spine

AP pelvis

AP hand

AP knee

Possible supplementary views:

Long tubular bone

Foot

Chest

Therapeutic Principles

Symptomatic orthopedic and dental therapy

Fig. 10.6 Cleidocranial dysplasia

Medial and lateral clavicular fragments (F), short, inferiorly deviated anterior ribs, short hypoplastic scapulae.

Fig. 10.7 Cleidocranial dysplasia

F	Early ossification of the ossification centers of the femoral head
I	Narrow hypoplastic ilium (I), wide sacroiliac joint space (IF), and Y-cartilage (Y)
OP	Pubic bone that is not yet ossified
SH	Varus position of the femoral neck

Therapeutic Principles

No causative therapy available

Symptomatic therapy of joint contracture and spinal deformity

Mucopolysaccharidoses (MPS) and Mucolipidoses (ML)

Pathology

Mucopolysaccharidosis (MPS):

– Autosomal recessive

– Exception: Hurler II diseases (X-chromosomal recessive)

– Inherited lysosomal enzyme defect

– Disturbed breakdown of mucopoly-saccharides

Mucolipidosis (ML):

– Lysosomal storage disease

– Clinically and biochemically similar to MPS and sphingolipidosis

– Storage of mucopolysaccharides and lipids in bones, central nervous system (CNS), liver, and heart

Clinical Findings

Strikingly coarse facial features

Short stature

Mental retardation

Facultative: opacified cornea, deafness

Diagnostic Evaluation

Recommended views

Lateral skull

Lateral spine

AP pelvis

AP hand

AP knee

Findings

Thickened, stubby scapulae

Shallow glenoid fossae

Short and thickened clavicles and ribs

Constriction of the proximal humeri (Fig. 10.8)

(→ Supplementary method)

Indications

Storage processes in parenchymal organs

Findings

Heart: thickened myocardium

Liver: diffuse increase in echogenicity

CNS (in newborns): white-matter lesions

(→ Supplementary method)

Indications

Storage processes in parenchymal organs

Technical parameters

T2-weighted spin-echo (SE)/fluid-attenuated inversion recovery (FLAIR) sequences:

Axial and coronal sections

Findings

Heart: thickened myocardium; diffuse signal alteration

Liver: diffuse signal alteration

CNS: white-matter lesions

Fig. 10.8 Mucolipidosis II (type “l-cell disease”)

S	Stubby scapula
G	Shallow, hypoplastic glenoid fossa
Black arrow	Thickened clavicle
White and black arrows	Wide ribs with posterior tapering

Fig. 10.9 Fibrous dysplasia

Monomelic unilateral manifestation of the humerus. Cystic osteolytic lesions, thinning and bulging of the cortex (C), remaining in part only as osseous bridge.

O	Osteolyses

Fibrous Dysplasia

Pathology

Bone replaced with fibrous connective tissue

“Tumor-like lesion”

Associated with precocious puberty and cutaneous pigmentation: McCune-Albright disease

Clinical Findings

Preferred age: 5–15 years

Solitary lesions:

– Maxilla, femur, tibia

– Can remain subclinical

Multiple lesions:

– Monomelic, unilateral, generalized

– Initially painful

– Later, spontaneous fractures

Diagnostic Evaluation

Findings

Bone expansion with loss of normal modelling

Cystic osteolytic patches

Cortical erosions

Scanty spongiosa: hourglass phenomenon

Later, shepherd crook deformity of the proximal femur

After cessation of growth, decreasing activity and increasing stability (Fig. 10.9)

(→ Supplementary method)

Indications

To address the question of possible malignant transformation

For the differential diagnosis

Findings

Hypointensity on T1- and T2 -weighted SE sequences: Fibrous tissue

Exception: Proliferative, expansile tissue:

– Hypercellular components

– Increased water content

Therapeutic Principles

Surgical correction if stability at risk

In adults, filling with spongiosa

In children, frequent resorption of the filling material

Osteogenesis Imperfecta

Pathology

Impaired periosteal new bone formation

Impaired collagenous production

Decreased bone density

Increased bone fragility

Clinical Findings

Frequent fractures (following inadequate trauma)

Deformities

Dwarfism

Type I:

– Blue sclerae

– Autosomal dominant (former type Lobstein)

Type II:

– Congenital form

– New mutation (former type Vrolik)

Type III:

– Progressive deformity: long tubular bones, skull, spine

Type IV:

– Like type I but without blue sclerae

Diagnostic Evaluation

Findings

Severe demineralization

Thin cortex

Deficient trabeculation of the spongiosa

Slender tubular shafts

Coexistent old and recent fractures

Deformity caused by healing of malaligned fractures (Fig. 10.10)

Indications

Prenatal diagnosis of type II

Therapeutic Principles

General goal: Upright position of the patient

Orthosis after age two years

Stabilization with intramedullary fixation

Fig. 10.10 Osteogenesis imperfecta

Manifestation of osteogenesis imperfecta with extensive osteopenia. Multiple fractures (F) of humeri, ribs, and clavicles, partially healed in malalignment.

Diagnostic Guidelines for Malformations

1 CR (method of choice)

In general AP projection (contralateral comparison)

Specific projections depending on clinical question

“Minimal bone program” in osteochondrodysplasias

2 MRI (supplementary method)

Surrounding soft tissues

Associated malformations: Spine, spinal canal, CNS storage processes

3 US (supplementary method)

Storage processes: Heart, liver, CNS (newborns!)

Prenatal diagnosis

Therapeutic Principles

Conservative

Immobilization

Positioning

Surgical

Internal fixation

Possibly rerotation osteotomy

Traumatology

Epiphyseal Separation Due to Birth Trauma

Pathology

Mechanical separation and/or displacement of the cartilage epiphysis

Accompanying plexus palsy (Erb-Duchenne) possible

Clinical Findings

Painfully restricted mobility

Spontaneous rest position

Diagnostic Evaluation

(→ Method of choice in the acute phase)

Recommended planes

Coronal sections parallel to the humerus (contralateral comparison!)

Indications

Evaluation of epiphyseal displacement

Assessment of perfusion with Doppler sonography

Documentation of ossification centers (Figs. 10.11–10.15)

Indications

Selectively during follow-up

Indications

Suitable for follow-up

Fig. 10.11 Epiphyseolysis due to birth trauma (Aitken I)

Left image: Longitudinal sonographic section parallel to the proximal humerus, showing a normal finding. The preformed cartilaginous epiphysis is seen along the reflected sound waves, surrounded by the periosteal tube. Interposed growth plate.

Right image: Same section as on the left. Hematoma-induced periosteal thickening of shell-like configuration, small osseous metaphyseal avulsions (arrow), minimally residual epiphyseal displacement after reduction, and internal fixation of the epiphyses. The parallel echogenic structures in the center of the epiphysis correspond to the pin.

E	Epiphysis
H	Humerus
W	Growth plate
E	Epiphysis
PV	Periosteal thickening
S	Pin

Fig. 10.12 Epiphyseolysis due to birth trauma

Longitudinal sonographic section along the proximal humerus. Displaced epiphysis, partially immersed in the acoustic shadow (SS) of the osseous humeral shaft.

W	Growth plate
SS	Acoustic shadow

Fig. 10.13 Epiphyseolysis due to birth trauma

Radiographic follow-up after reduction and internal fixation: Radiographically invisible epiphysis (!), early, barely discernible callus formation along the lateral border of the metaphysis. In contrast to sonography, the radiograph provides no relevant information for the follow-up at this stage.

E	Epiphysis
K	Callus

Fig. 10.14 Epiphyseolysis due to birth trauma

Doppler sonography to visualize the cartilaginous epiphysis (E) and its perfusion, indicative of viability of the ossification center after reduction and internal fixation.

Fig. 10.15 Epiphyseolysis due to birth trauma

Radiographic follow-up after one year. Confirmation of the Doppler sonographic finding of Fig. 10.14. Age-dependent development of both ossification centers (OK) in the proximal humeral epiphysis.

Therapeutic Principles

Conservative

Dressing for pain relief

Desault bandage

For markedly overlapping fractures, knapsack dressing

Surgical

For severely dislocated proximal fractures in older children, open reduction and internal fixation

Clavicular Fractures

Pathology

Fracture usually occurs in the midshaft

Greenstick fractures comprise 50%

Medial fractures (3%):

– Usually with epiphyseolysis

– Growth disturbance due to premature closure of the growth plate

– No functional deficits!

Lateral fractures (5%):

– Usually pseudodislocations

– Central fragment dislocated outside the periosteal tube

– Intact ligamentous connection between acromion, coracoid, and clavicle (Figs. 10.16–10.19)

Diagnostic Evaluation

(→ Method of choice)

Recommended views

AP projection as baseline documentation

Generally no follow-up necessary

(→ Supplementary method)

Indications

Substitute for conventional radiography (CR) in classical fractures

No recollection of trauma

Painful swelling (Fig. 10.20)

Fig. 10.16 Diagram of clavicular fractures

Fig. 10.17 Greenstick fracture of the clavicle

Typical manifestation of a greenstick fracture (F) of the clavicle.

Fig. 10.18 Lateral fracture of the clavicle

Lateral fracture (F) of the clavicle, also referred to as pseudodislocation. Incidentally visualized is an ossification center in the coracoid (arrow).