Ultrasonography

Use of USG for the Infant Brain

Congenital Anomalies:

Chiari malformation

• Chiari I: Downward displacement of the cerebellar tonsil without displacement of the 4th ventricle/medulla.

• Chiari II: Commonest anomaly and is almost always associated with spina bifida and meningomyelocele. Here, there is a downward displacement of the cerebellar tonsils along with pons and medulla through an enlarged foramen magnum into the upper spinal canal. 4th ventricle is also elongated into the upper spinal canal and posterior fossa in small.

• Chiari III: High cervical or occipital encephalocele.

• Chiari IV: Severe cerebellar hypoplasia

Dandy-Walker malformation

Presents with large posterior fossa cyst, which communicates with the 4th ventricle, hypoplastic cerebellar hemispheres, and absent/rudimentary inferior vermis. This must be differentiated from other posterior fossa cystic abnormalities like cisterna magna, trapped 4th ventricle, and arachnoid cyst.

Agenesis of the corpus callosum

It may be partial/complete and usually associated with other anomalies.

Holoprosencephaly

Maybe alobar, semi lobar, lobar, and usually associated with facial & calvarial anomalies.

Hydranencephaly

Could be confused with alobar holoprosencephaly but the presence of 'falx' helps to differentiate this lesion. It is difficult to differentiate it from severe hydrocephalus but a thin rim of cortex should be seen in hydrocephalus.

Hydrocephalus

For diagnosis, grading severity, and post-shunt follow up.

Hemorrhage

Germinal matrix hemorrhage may occur in the subependymal, intraventricular, or intraparenchymal region and is more commonly seen in premature and low birth weight infants. Subdural, epidural and subarachnoid hemorrhages are other less common sites of intracranial hemorrhage.

Hypoxic ischemic encephalopathy (HIE)

Periventricular leukomalacia and periventricular hemorrhagic infarction are the primary manifestations of HIE in the premature infant. Perinatal asphyxia in the term infant can cause diffuse cerebral edema which may progress to brain atrophy/multicystic encephalomalacia. Doppler studies would reveal a lack of Doppler signal/flow

Infections

Inflammation, edema, and vasculitis are common to all cerebral infections. Ultrasound plays an important role in identifying and following both antenatal and neonatal complications (echogenic sulci, intra-axial fluid collection, hydrocephalus, ventriculitis, abnormal parenchymal echogenicity, abscess, encephalomalacia, and calcifications) from congenital (TORCH) infections.

Intracranial masses

Most tumors presenting before 2 years of age are congenital (PNET, low-grade astrocytoma, craniopharyngioma, teratoma). Ultrasound has a role in screening infants and helps to differentiate solid, cystic, or vascular components of the masses.

Cystic lesions in the brain include arachnoid cysts, Dandy-Walker cysts, porencephalic cysts, choroid plexus cysts, subependymal and colloid cysts.

Vascular malformations

Duplex/color Doppler ultrasound helps to differentiate arteriovenous malformation such as Vein of Galen aneurysm from other cystic lesions.

USG and Pediatric Abdomen

Abdominal mass

The spectrum of pathology encountered in the neonate is different from that in older children and is much more likely to be a congenital abnormality rather than a malignancy.

Renal masses

They are the commonest course of abdominal mass in both infants and children, accounting for more than 50%.

Solid renal masses

Bilateral renal masses

• Autosomal recessive polycystic renal disease - usually associated with congenital hepatic fibrosis with/without portal hypertension.

• Nephroblastomatosis

• Renal vein thrombosis

Cystic renal masses

• Hydronephrosis accounts for 50% of the renal masses. Etiological factors could be PUJ obstruction, VUR, megaloureter, VUJ obstruction, duplex system, posterior urethral valves, bladder outlet obstruction.

• Multicystic dysplastic kidney disease

• Autosomal dominant polycystic renal disease

• Autosomal recessive polycystic renal disease

• Tuberous sclerosis

Adrenal masses

• Neuroblastoma: second commonest abdominal mass found in children after Wilm's tumor

• Adrenal hemorrhage

• Other adrenal masses are pheochromocytomas (extremely rare) and adrenal carcinoma

Hepatic masses

Focal hepatic masses

• Hepatoblastoma: Third commonest malignancy seen in childhood after Wilm's tumor and neuroblastoma.

• Hepatocellular carcinoma

• Hemangioma and hemangioendothelioma

• Metastasis - Wilm's, neuroblastoma, lymphoma, leukemia, rhabdomyosarcoma

• Mesenchymal hamartomas

• Adenomas, teratomas

• Infection- amoebic/pyogenic abscess, hydatid cyst

Diffuse hepatic lesion

• Hepatomegaly: Glycogen storage disease, fatty liver, infections (malaria, typhoid)

Other abdominal masses

Cystic masses

• Mesenchymal & omental cyst

• Cystic teratoma

• Duplication cyst

• Ovarian cyst

• Hydrometrocolpos

• Pancreatic pseudocyst

Solid masses

• Lymphoma

• Rhabdomyosarcoma

• Lymphadenopathy

Infections - Tuberculosis, HIV

Neoplastic - Lymphoma, Leukemia

• Appendicular abscess

• Undescended testis

• Splenic lesions: lymphoma, Gaucher's disease, abscess, cyst, hydatid, infection (malaria, typhoid).

Urinary tract infection:

It is the 1st line of investigation in any child with a proven urinary tract infection. Vesicoureteral reflux may be demonstrated by non-invasive means with the aid of color Doppler examination. Acute pyelonephritis, acute lobar nephronia, renal abscess, pyonephrosis, chronic pyelonephritis, and neonatal candidiasis can also be detected.

The acute abdomen:

Appendicitis: commonest cause

Intussusception: diagnosis & treatment (hydrostatic reduction)

Pyelonephritis

Cystitis

Pancreatitis

Cholecystitis

Gastroenteritis

Mesenteric adenitis very limited role

Meckel's diverticulum

Renal calculi

Intestinal obstruction

The vomiting infant:

Hypertrophic pyloric stenosis

Duodenal obstruction - Malrotation & volvulus - Colour Doppler studies to aid in the diagnosis by demonstrating SMV anterior or to the left of SMA

Gastroesophageal reflux

Duodenal atresia

Trauma:

Ultrasound forms the first line of investigation to look for free fluid in the abdomen and injury (contusions/lacerations/hematoma) to the liver, kidney, spleen, pancreas & bladder.

Jaundice in the neonate:

Ultrasound helps to differentiate between neonatal hepatitis, biliary atresia, and choledochal cyst- the three common causes of neonatal jaundice.

Medical renal disease:

• Acute and chronic glomerulonephritis

• Grading severity of the parenchymal disease

• Nephrocalcinosis: cortical/medullary
• Medullary (common causes): Medullary sponge kidney, renal tubular acidosis, hyperparathyroidism, hypervitaminosis D, hypercalcemia, hypercalciuria, milk-alkali syndrome, hyperoxaluria
• Cortical - Glomerular nephritis

USG and Pediatric Chest

• Identification of pleural effusion and to guide tapping

• Evaluation of diaphragmatic motion to assess diaphragmatic paralysis

• Differentiate between cystic/solid intrathoracic mass.

• Evaluation of diaphragmatic hernia

• Diagnosis of pericardial effusion

• Differentiate chest wall mass from pleural effusion

• Guidance of needle aspiration biopsy of masses or fluid collection

• Characterization of mediastinal masses

• Detection of extension of neck masses into the chest

USG and Pediatric Head and Neck Masses

Information of the salivary glands: Acute/chronic parotitis

Lymphadenopathy: inflammatory, infective, sarcoidosis, lymphoma

Neoplasms:

• Hemangioendothelioma

• Hemangiomas

• Lymphangiomas/cystic hygromas

• Salivary gland tumours - pleomorphic adenomas of parotid gland

• Mucoepidermoid carcinomas

• Undifferentiated sarcoma

• Neurofibromas

• Neuroblastomas

• Rhabdomyosarcoma

• Lymphoma

• Teratoma

  Brachial cleft cysts/sinuses

  Encephalocele/cervical meningocele

  Doppler imaging useful in identifying erratic carotid artery, pseudoaneurysm

  Retropharyngeal/parapharyngeal abscess

  Pathologies of the thyroid gland

• Inflammatory: Acute suppurative thyroiditis, Hashimoto's thyroiditis, Turner's, Noonan's syndrome, Down's syndrome, treated Hodgkin's lymphoma, dilantin therapy

• Neoplasms: Adenoma, Papillary carcinoma, Follicular carcinoma - rare, Medullary carcinoma - rare

  Multinodular goitre, Multiple thyroid cyst - McCune Albright syndrome

• Congenital lesions: Thyroglossal cyst, Congenital goitre, Congenital cyst - very rare, Thymic cyst

USG and Pediatric Spinal Canal

The sonographic study of the intact spinal canal is unique to the pediatric age group because of the incomplete ossification of the posterior elements.

• To determine the level of conus medullaris - look for tethered cord

• Myelomeningocele, meningocele, lipomyelomeningocele, hydromyelia, syringomyelia, syringohydromyelia, diastematomyelia

• Lipoma

USG and Pediatric Pelvis

Congenital anomalies of the uterus & vagina:

• Bicornuate, unicornuate and T shaped uterus

• Obstruction of the vagina resulting in hydrocolpos or hydrometrocolpos (vaginal atresia, imperforated hymen, vaginal septum)

• Uterine hypoplasia

• Streak ovaries: Turner's syndrome

Neoplasms of uterus:

• Rhabdomyosarcoma

• Endodermal sinus tumor

• Adenocarcinoma of cervix

• Carcinoma of the vagina (h/o in utero exposure to diethylstilbestrol)

• Gartner's duct cyst

• Paramesonephric (Mullerian) duct cyst

Neoplasms of ovary:

• Ovarian cysts

• Primary ovarian tumours:
  Germ cell tumours: Benign teratoma, dysgerminoma (common),embryonal cell carcinoma (rare), endodermal sinus tumour (rare)

  Epithelial tumours: Serous & mucinous adenocarcinoma are rare before puberty

  Stromal tumour: Granulosa theca cell tumour

  Acute leukaemia

Endocrine abnormalities:

The newborn infant with ambiguous genitalia to look for the presence/absence of uterus and vagina.

Investigation for primary amenorrhoea - to assess uterine - size, shape & maturity, ovarian development

Gonadal dysgenesis

• Turner's syndrome (ovarian absent or streak)

• Swyer's syndrome (pure gonadal dysgenesis)

• Noonan's syndrome (pseudo-Turner's syndrome)(normal ovarian function & normal ovaries on ultrasound)

• Testicular feminization: Absent uterus & ovaries, blind-ending vagina. The testis is ectopic (pelvic).

Precocious puberty: Uterus enlarged and ovarian volume >1 cc before the age of 8 yrs.

• Pseudoprecocious puberty: Usually secondary to ovarian tumors -> granulosa theca cell tumor, dysgerminoma, functional ovarian cyst, teratoma, choriocarcinoma, feminizing adrenal tumors.

USG and Pediatric Scrotum

• Undescended testis: Commonest ectopic location being the inguinal canal

• Hydrocele: Due to patent processus vaginalis, infection, inflammation, trauma - hematocele, tumour

• Testicular torsion: Colour Doppler imaging is used to differentiate torsion from acute epididymo-orchitis.

• Scrotal hernia

• Neoplasms

Primary testicular neoplasms

Germ cell tumours: endodermal sinus tumours, embryonal carcinoma. Rarely: Seminoma, teratocarcinoma and choriocarcinoma.

Non germ cell tumours:
Leydig cell tumours - precocious puberty

Sertoli cell tumour - feminization

Leukemia

Lymphoma

Metastasis from neuroblastoma

Rhabdomyosarcoma paratesticular

• Epididymitis

• Trauma: contusion, hematoma or rupture of testis, hydrocele

• Varicoceles Post-pubertal males

• Spermatoceles Post-pubertal males

Doppler Examination of the Abdomen

• Evaluation of the splanchnic venous system in the child with portal hypertension

• Assessment of the renal circulation in trauma and disease affecting the main renal arteries, veins, or small intrarenal vessels.

• Determination of patency of vessels (aorta and inferior vena cava), especially following surgery or in the presence of tumors

  (e.g. Wilm's)

• Evaluation of acute scrotal disease (torsion v/s epididymal-orchitis)

• Assessment of vascularity and rejection of transplant organs (kidney, liver)

• Identification of unknown structure (tortuous portal vein versus dilated bile duct, dilated vein versus dilated ureter or lymphatic channel)

• Identifying refluxing or obstructed ureter by the abnormal urine jet it emits into the bladder.

• Distinguishing obstructive hydronephrosis from other causes of urinary tract dilatation by assessing intra-renal arterial resistance

• Defining the malignant nature of a mass by its abnormal vascularisation

Orbital Ultrasound

• To study the posterior segment in case of congenital cataract, corneal opacity

• Evaluation of Vitreo-retinal disorders

• Identification & localization of intraocular foreign body

• Diagnosis & follow up of ocular tumors - retinoblastoma, metastasis (neuroblastoma, Ewing's sarcoma, lymphoma), optic nerve glioma, rhabdomyosarcoma, dermoid cyst

• Infections: cellulitis, orbital abscess, cysticercosis, hydatid cyst

Colour Doppler flow imaging

• Evaluation of ocular tumors

• Study of vascular disorders of the orbit-central retinal artery or vein occlusion, carotid-cavernous fistulae

• Orbital trauma

Ultrasonography - Introduction

With the advent of high-resolution real-time ultrasonography, this non-invasive, non-ionizing, low cost, and quick imaging modality has become the modality of choice for the rapid evaluation of the child. Ultrasound is ideally suited to pediatrics and examinations can often and safely be repeated, with no requirement of sedation.

The many applications of this portable, reliable, and comparatively cost-effective imaging modality are briefly discussed below.