Pediatric Radiology Practice Questions

Q: A child presents with multiple vertebral anomalies and a posterior mediastinal mass. What is the likely diagnosis?

Neuroenteric cyst. **Explanation:** The presence of a **posterior mediastinal mass** associated with **vertebral anomalies** (such as hemivertebrae, butterfly vertebrae, or scoliosis) is the classic imaging hallmark of a **Neuroenteric Cyst**. 1. **Why Neuroenteric Cyst is correct:** This congenital anomaly results from a failure of separation between the primitive endoderm (gut) and the ectoderm (notochord) during the 3rd week of gestation. This persistent connection leads to a cyst lined by gastrointestinal or respiratory epithelium, typically located in the posterior mediastinum. Because the notochord is involved, it is almost always associated with anterior vertebral body defects at or above the level of the cyst. 2. **Why the other options are incorrect:** * **Meningomyelocele:** While it involves vertebral defects, it is a neural tube defect characterized by the protrusion of meninges and spinal cord through a posterior vertebral arch defect, typically in the lumbosacral region, not as a mediastinal mass. * **Bronchogenic Cyst:** These are the most common foregut cysts but are usually located in the **middle mediastinum** (subcarinal) and are **not** typically associated with vertebral anomalies. * **Neuroblastoma:** This is the most common posterior mediastinal mass in children. While it can cause bone destruction or neural foraminal widening (dumb-bell tumor), it does not cause congenital vertebral malformations like hemivertebrae. **High-Yield NEET-PG Pearls:** * **Split Notochord Syndrome:** The spectrum of anomalies including neuroenteric cysts and vertebral defects. * **Location:** Most commonly found in the posterior mediastinum, slightly to the right. * **Imaging:** MRI is the modality of choice to visualize the cyst and its potential communication with the spinal canal. * **Key Association:** Always look for "Butterfly vertebrae" or "Hemivertebrae" in the clinical stem for Neuroenteric cysts.

Q: Antenatal detection of bone fractures on ultrasound suggests which of the following conditions?

Osteogenesis imperfecta. **Explanation:** **Osteogenesis Imperfecta (OI)**, specifically **Type II (Perinatal Lethal)**, is the most common cause of multiple fractures detected in utero. It is a genetic disorder characterized by a defect in Type I collagen synthesis. On antenatal ultrasound, the presence of multiple long bone fractures, "crumpled" or "accordion-like" femurs, and a soft, compressible skull (due to poor mineralization) are hallmark findings. The ribs may also show "beading" due to multiple healing fractures. **Analysis of Incorrect Options:** * **Achondroplasia:** This is the most common non-lethal skeletal dysplasia. It is characterized by rhizomelic (proximal) limb shortening and a large head with frontal bossing, but **not** by bone fragility or fractures. * **Marfan’s Syndrome:** This is a connective tissue disorder affecting fibrillin-1. While it involves skeletal abnormalities like arachnodactyly and pectus deformities, it does not cause prenatal bone fractures. * **Chondrodysplasia Punctata:** This group of disorders is characterized by "stippled epiphyses" (calcific spotting) on imaging. While it involves limb shortening, it is not typically associated with spontaneous intrauterine fractures. **High-Yield Clinical Pearls for NEET-PG:** * **OI Type II** is the most severe/lethal form; **OI Type I** is the mildest and most common. * **Blue sclera** and **dentinogenesis imperfecta** are classic clinical associations of OI. * **Hypophosphatasia** is another differential for prenatal fractures but is distinguished by near-total absence of ossification. * **Thanatophoric Dysplasia** is the most common *lethal* skeletal dysplasia (look for "cloverleaf skull" and "telephone receiver" femurs).

Q: What is the characteristic radiographic sign of acute laryngotracheobronchitis?

Steeple sign. **Explanation:** **Acute Laryngotracheobronchitis (Croup)** is a viral infection (most commonly caused by **Parainfluenza virus**) that leads to inflammation and subglottic edema. **Why "Steeple Sign" is correct:** In Croup, the inflammatory edema occurs in the subglottic region (just below the vocal cords). On an Anteroposterior (AP) neck X-ray, this narrowing of the subglottic airway creates a tapered, inverted "V" appearance, resembling a church steeple. This is the classic radiographic hallmark of the disease. **Analysis of Incorrect Options:** * **Thumb sign:** This is the characteristic finding of **Acute Epiglottitis**. On a lateral neck X-ray, the enlarged, edematous epiglottis appears rounded and thick, resembling a thumb. * **Vallecula sign:** This refers to the obliteration of the vallecular space on a lateral X-ray, also seen in **Acute Epiglottitis**. In a normal scan, the vallecula is a clear pocket of air; its disappearance indicates significant epiglottic swelling. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Barking cough, inspiratory stridor, and hoarseness. * **Age Group:** Typically affects children aged 6 months to 3 years. * **Radiology Tip:** The Steeple sign is seen on the **AP view**, whereas the Thumb sign is seen on the **Lateral view**. * **Management:** Nebulized adrenaline (for immediate relief of edema) and Dexamethasone (to reduce inflammation) are the mainstays of treatment.

Q: Antenatal ultrasound demonstrating a double bubble appearance is typically indicative of which of the following conditions?

Duodenal atresia. ### Explanation **Correct Answer: B. Duodenal atresia** The **"Double Bubble" sign** is a classic radiological hallmark of duodenal obstruction. In duodenal atresia, there is a failure of recanalization of the duodenum during the 8th–10th week of gestation. * **Mechanism:** The "bubbles" represent the gaseous (or fluid-filled, on antenatal USG) distension of the **stomach** and the **proximal duodenum**, separated by the pyloric sphincter. * **Antenatal USG:** It appears as two echo-free cystic structures in the upper abdomen. It is frequently associated with **polyhydramnios** because the fetus cannot effectively swallow and absorb amniotic fluid. **Why other options are incorrect:** * **A. Diaphragmatic hernia:** Typically presents with a "scaphoid abdomen" postnatally. On USG, one would see abdominal contents (bowel loops, stomach) in the thoracic cavity and a mediastinal shift. * **C. Gastric volvulus:** This is an acute surgical emergency involving rotation of the stomach. While it causes gastric outlet obstruction, it does not typically produce the specific "double bubble" configuration. * **D. Intussusception:** This is primarily a disease of infants (6–18 months), not usually seen antenatally. The classic USG sign is the **"Target" or "Donut" sign**. **High-Yield Clinical Pearls for NEET-PG:** * **Association:** Approximately 30% of infants with duodenal atresia have **Down Syndrome (Trisomy 21)**. * **X-ray finding:** Postnatally, an abdominal X-ray shows two air-filled bubbles with a complete absence of distal bowel gas. * **Differential for Double Bubble:** While duodenal atresia is the most common cause, other causes include **annular pancreas**, peritoneal (Ladd's) bands, and malrotation. * **VACTERL association:** Always screen for other congenital anomalies (Vertebral, Anal, Cardiac, Tracheo-Esophageal, Renal, and Limb).

Q: What is the characteristic radiological sign observed in Croup?

Steeple sign. **Explanation:** **Croup (Laryngotracheobronchitis)** is a common pediatric viral infection, most frequently caused by the **Parainfluenza virus**. The characteristic radiological finding is the **Steeple sign**, seen on an anteroposterior (AP) neck X-ray. This sign is produced by the subglottic narrowing of the airway due to inflammatory edema, which gives the trachea a tapered, pointed appearance resembling a church steeple. **Analysis of Options:** * **A. Steeple sign (Correct):** Represents subglottic narrowing. It is the classic radiographic hallmark of Croup. * **B. Epiglottic swelling:** This is the hallmark of **Acute Epiglottitis**. On a lateral neck X-ray, this appears as the **"Thumb sign"** due to an enlarged, rounded epiglottis. * **C. Abnormal laryngeal cartilage:** This is associated with **Laryngomalacia**, the most common cause of congenital stridor, characterized by inward collapse of supraglottic structures during inspiration. * **D. Peritonsillar abscess:** This is a clinical diagnosis (Quinsy) characterized by uvular deviation and trismus; radiologically, it may show soft tissue swelling but not the steeple sign. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Barking cough, inspiratory stridor, and hoarseness. * **Age Group:** Typically affects children aged 6 months to 3 years. * **Management:** Mild cases are treated with oral Dexamethasone; severe cases require nebulized L-epinephrine (Adrenaline). * **Radiology Tip:** While the Steeple sign is classic, it is only present in about 50% of cases; diagnosis is primarily clinical. Always look for the "Thumb sign" to rule out the more life-threatening Epiglottitis.

Q: A contrast enema is performed on a one-day-old infant presenting with bilious emesis and abdominal distension. Based on the findings, which of the following is the MOST likely diagnosis?

Meconium ileus. ***Meconium ileus*** - Contrast enema shows **microcolon** (small, unused colon) with **pellet-like filling defects** in the terminal ileum due to inspissated meconium. - Associated with **cystic fibrosis** in 85-90% of cases, presenting with **bilious vomiting** and **abdominal distension** in neonates. *Hirschsprung Disease* - Contrast enema demonstrates a **transition zone** between the normal proximal bowel and the aganglionic distal segment. - Shows **delayed evacuation** of contrast on 24-hour films, but no microcolon or ileal filling defects. *Meconium Plug Syndrome* - Contrast enema reveals a **colonic plug** that can be evacuated with the enema, with **normal caliber colon**. - No microcolon present, and the obstruction is limited to the **left colon** without ileal involvement. *Small Left Colon Syndrome* - Shows **narrowed left colon** with a **transition point at the splenic flexure**, creating a caliber change. - The **right colon** appears normal or dilated, contrasting with the uniformly small colon seen in meconium ileus.

Q: Reflux of urine into the pelvis and calyces with mild dilatation and minimal blunting of fornices indicates which grade of Vesicoureteral Reflux (VUR)?

Grade III. The grading of **Vesicoureteral Reflux (VUR)** is based on the International Reflux Study in Children, primarily assessed via Voiding Cystourethrogram (VCUG). ### **Why Grade III is Correct** In **Grade III**, reflux reaches the renal pelvis and calyces. The key diagnostic features are **mild dilatation** of the ureter and renal pelvis, with **minimal blunting (effacement) of the calyceal fornices**. The papillary impressions are still visible, but the sharp "cupping" of the calyces begins to round off. ### **Analysis of Incorrect Options** * **Grade I (Option D):** Reflux is limited to the **ureter only**; it does not reach the renal pelvis. * **Grade II (Option A):** Reflux reaches the pelvis and calyces, but there is **no dilatation**. The calyceal fornices remain sharp and normal in configuration. * **Grade IV (Option C):** Characterized by **moderate dilatation** and tortuosity of the ureter and pelvis. The sharp angle of the fornices is completely lost, though papillary impressions may still be faintly visible. * **Grade V:** Severe dilatation and gross tortuosity of the ureter and pelvis. There is a complete loss of papillary impressions (intrarenal reflux). ### **High-Yield Clinical Pearls for NEET-PG** * **Investigation of Choice:** Voiding Cystourethrogram (**VCUG**) is the gold standard for grading VUR. * **Radionuclide Cystogram (RNC):** More sensitive for follow-up and screening siblings due to lower radiation dose, but provides poor anatomical detail. * **Management:** Grades I-II often resolve spontaneously with medical management (prophylactic antibiotics). Grades IV-V or breakthrough infections often require surgical intervention (e.g., Ureteral Reimplantation). * **Associated Pathology:** VUR is a major risk factor for **Pyelonephritis** and subsequent **Renal Scarring** (Reflux Nephropathy).

Q: The 'steeple sign' on a radiograph is characteristic of which condition?

Laryngotracheobronchitis. **Explanation:** **Laryngotracheobronchitis (Croup)** is the correct answer. The 'steeple sign' (also known as the wine bottle sign) is a classic radiologic finding seen on an **anteroposterior (AP) view** of the neck. It represents subglottic narrowing caused by inflammatory edema in the subglottic region. The narrowing of the tracheal lumen creates a tapered appearance resembling a church steeple. Croup is most commonly caused by the **Parainfluenza virus (Type 1)** and typically presents with a barking cough, inspiratory stridor, and hoarseness in children aged 6 months to 3 years. **Why other options are incorrect:** * **Acute Epiglottitis:** This condition is characterized by the **'Thumb sign'** on a **lateral neck X-ray**, representing a swollen, enlarged epiglottis. Unlike Croup, the subglottic space remains normal. It is a medical emergency usually caused by *Haemophilus influenzae* type b (Hib). * **Option C & D:** These are incorrect because the steeple sign is pathognomonic for subglottic narrowing (Croup) and is distinctly different from the supraglottic swelling seen in epiglottitis. **NEET-PG High-Yield Pearls:** * **Croup:** Steeple sign (AP view), Subglottic narrowing, Barking cough, Parainfluenza virus. * **Epiglottitis:** Thumb sign (Lateral view), Supraglottic swelling, Drooling, Tripod position, *H. influenzae*. * **Management Tip:** Nebulized adrenaline and corticosteroids (Dexamethasone) are the mainstays of treatment for moderate-to-severe Croup. Avoid examining the throat in suspected epiglottitis as it may trigger laryngospasm.

Question 1

A child presents with multiple vertebral anomalies and a posterior mediastinal mass. What is the likely diagnosis?

Accepted Answer

Neuroenteric cyst

Answer

Meningomyelocele

Answer

Bronchogenic cyst

Answer

Neuroblastoma

Question 2

Antenatal detection of bone fractures on ultrasound suggests which of the following conditions?

Accepted Answer

Osteogenesis imperfecta

Answer

Achondroplasia

Answer

Marfan's syndrome

Answer

Chondrodysplasia punctata

Question 3

What is the characteristic radiographic sign of acute laryngotracheobronchitis?

Accepted Answer

Steeple sign

Answer

Thumb sign

Answer

Vellecula sign

Answer

None of the above

Question 4

Antenatal ultrasound demonstrating a double bubble appearance is typically indicative of which of the following conditions?

Accepted Answer

Duodenal atresia

Answer

Diaphragmatic hernia

Answer

Gastric volvulus

Answer

Intussusception

Question 5

Time sector scanning of neonates is preferred because of which most practical reason?

Accepted Answer

Open fontanelles

Answer

Inexpensive equipment

Answer

Children are more co-operative

Answer

Better resolution

Question 6

What is the characteristic radiological sign observed in Croup?

Accepted Answer

Steeple sign

Answer

Epiglottic swelling

Answer

Abnormal laryngeal cartilage

Answer

Peritonsillar abscess

Question 7

A contrast enema is performed on a one-day-old infant presenting with bilious emesis and abdominal distension. Based on the findings, which of the following is the MOST likely diagnosis?

Accepted Answer

Meconium ileus

Answer

Hirschsprung Disease

Answer

Meconium Plug Syndrome

Answer

Small Left Colon Syndrome

Question 8

What is the most common cause of a mass in the posterior mediastinum in children?

Accepted Answer

Neuroblastoma

Answer

Rhabdomyosarcoma

Answer

Duplication cyst of the esophagus

Answer

Lymphoma

Question 9

Reflux of urine into the pelvis and calyces with mild dilatation and minimal blunting of fornices indicates which grade of Vesicoureteral Reflux (VUR)?

Accepted Answer

Grade III

Answer

Grade II

Answer

Grade IV

Answer

Grade I

Question 10

The 'steeple sign' on a radiograph is characteristic of which condition?

Accepted Answer

Laryngotracheobronchitis

Answer

Acute epiglottitis

Answer

Both acute epiglottitis and laryngotracheobronchitis

Answer

None of the above

Pediatric Radiology — MCQs

Pediatric Radiology — MCQs

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