Paediatric radiology demands a separate mental framework — neonatal brain and spine, congenital heart disease, and childhood tumours. These free samples from the RadioQBank published set come with full explanations, exam pearls, and references.
Question 1 · Neonatal Spine · easy
Which of the following is the MOST accurate statement regarding spinal cord ultrasound technique in neonates?
- a. A high-frequency linear transducer (7.5–15 MHz) is used with the infant in prone position for optimal imaging
- b. The posterior fontanelle is used as the acoustic window for spinal cord evaluation
- c. Spinal ultrasound is only valid until 3 months of age, after which posterior spinal elements ossify
- d. Doppler assessment of the conus medullaris is required in all spinal US examinations
Answer: A. Spinal cord ultrasound in neonates uses a high-frequency (7.5–15 MHz) linear transducer in the prone position. The posterior elements of the neonatal spine are incompletely ossified, providing an acoustic window through the laminae and spinous processes. Sagittal and axial views evaluate cord level, conus position, filum diameter, and detect cysts, lipomas, or tethering lesions.
Exam pearl: Neonatal spinal US: high-frequency linear probe + prone position; best window before 12 weeks; assesses conus level and filum.
Grainger & Allison 7th ed; AIIMS-MAMC-PGI Guide
Question 2 · Congenital Heart Disease · easy
A 2-day-old neonate presents with sudden cardiovascular collapse, metabolic acidosis, and absent femoral pulses. Echocardiography reveals severe narrowing of the aortic arch with a gradient of 50 mmHg across the narrowing. Prostaglandin E1 partially restores lower limb perfusion. What is the most likely diagnosis?
- a. Critical coarctation of the aorta
- b. Hypoplastic left heart syndrome
- c. Interrupted aortic arch
- d. Aortic stenosis
Answer: A. Critical coarctation of the aorta presents in the first days of life when the ductus arteriosus closes, removing the bypass pathway that maintained lower body perfusion. The lower limb circulation becomes dependent on ductal right-to-left shunting (RA → PA → ductus → descending aorta). Restoration of ductal patency with PGE1 rapidly improves lower limb perfusion. The gradient demonstrates the obstruction. Definitive treatment: surgical repair (resection and end-to-end anastomosis) or catheter-based balloon dilation in selected cases.
Exam pearl: Critical neonatal CoA = absent femoral pulses + collapse as PDA closes; PGE1 reopens PDA; surgical repair is definitive.
Grainger & Allison 7th ed; AIIMS-MAMC-PGI Radiology Guide
Question 3 · DDH · moderate
A 3-year-old child with known DDH treated with Pavlik harness has a follow-up MRI. The MRI shows high T1 signal in the femoral head epiphysis with irregular contour and collapse. What complication has occurred?
- a. Transient synovitis
- b. Avascular necrosis (AVN) of the femoral head
- c. Developmental coxa vara
- d. Septic arthritis
Answer: B. Avascular necrosis (AVN) of the femoral head is the most feared complication of DDH treatment — particularly Pavlik harness and closed/open reduction. The excessive abduction in Pavlik harness can compress the medial circumflex femoral artery, causing AVN. MRI is the most sensitive modality, showing subchondral T1 hypointensity (marrow necrosis), irregular contour, and eventual collapse. Plain X-ray may show fragmentation.
Exam pearl: AVN = most feared DDH treatment complication; MRI most sensitive; T1 hypointense epiphysis = femoral head ischaemia.
Grainger & Allison 7th ed; AIIMS-MAMC-PGI Guide
Question 4 · Paediatric Abdomen · moderate
All of the following correctly describe the SIOP protocol for Wilms tumour EXCEPT:
- a. Neoadjuvant chemotherapy is given before surgery in most cases
- b. Pre-operative biopsy is mandatory to confirm diagnosis before chemotherapy
- c. Chemotherapy is given for 4–6 weeks before nephrectomy in localised disease
- d. Tumour rupture risk is reduced by pre-operative chemotherapy
Answer: B. In the SIOP (Société Internationale d'Oncologie Pédiatrique) protocol for Wilms tumour, pre-operative biopsy is NOT mandatory. SIOP relies on clinical and imaging criteria (age 6 months–16 years with a unilateral intrarenal mass) to diagnose Wilms tumour presumptively and commences neoadjuvant chemotherapy WITHOUT histological confirmation. The rationale is that the diagnostic accuracy of imaging + clinical criteria is >95%, and avoiding biopsy reduces tumour seeding risk. Biopsy is reserved for atypical cases. This contrasts with the COG (North American) protocol, which typically performs upfront nephrectomy without neoadjuvant therapy.
Exam pearl: SIOP vs COG for Wilms: SIOP = chemo FIRST, no mandatory biopsy; COG = surgery FIRST — image-based diagnosis vs histological confirmation.
Pediatric Radiology 2017;47:1095; AIIMS-MAMC-PGI Comprehensive Guide
Question 5 · Neonatal Brain · hard
A neonatal MRI brain at 40 weeks corrected age in a preterm infant shows: bilateral periventricular T2 hyperintensity, reduced posterior white matter volume, dilated posterior horns of the lateral ventricles (colpocephaly), and absent posterior body of the corpus callosum. What pattern of injury does this represent?
- a. Bilateral MCA territory infarction
- b. Periventricular white matter injury of prematurity (PWMI) with secondary corpus callosum thinning
- c. Primary agenesis of the corpus callosum
- d. Congenital CMV with periventricular leukomalacia
Answer: B. Periventricular white matter injury of prematurity (PWMI) — the modern successor to PVL — causes diffuse non-cystic white matter injury. At term-equivalent MRI, it manifests as: periventricular T2 hyperintensity, reduced posterior white matter volume, colpocephaly (dilatation of posterior horns from white matter loss), thinned posterior body and splenium of corpus callosum (secondary to reduced axonal projections), and delayed myelination. This is secondary corpus callosum thinning, not primary agenesis.
Exam pearl: PWMI at term MRI: periventricular T2 + colpocephaly + secondary CC thinning; posterior horn dilatation = white matter volume loss.
Osborn's Brain 3rd ed; Radiographics 2014 — Preterm brain injury