Pediatric Radiology Practice Questions

Q: What is the most characteristic radiographic sign in a child with leukemia?

Metaphyseal translucencies. **Explanation:** In pediatric leukemia (most commonly Acute Lymphoblastic Leukemia - ALL), skeletal changes are present in approximately 50–70% of cases due to the rapid proliferation of leukemic cells within the bone marrow. **1. Why Metaphyseal Translucencies are correct:** The most characteristic and earliest radiographic sign is the **"Leukemic Line"**—a transverse radiolucent band located at the metaphysis, just proximal to the zone of provisional calcification. This occurs because the hypercellular leukemic marrow exerts pressure and interferes with normal endochondral ossification, leading to deficient bone formation in the most metabolically active area. **2. Analysis of Incorrect Options:** * **A. Osteosclerosis:** This is rare in leukemia. Sclerosis is more typical of bone metastases (like neuroblastoma) or certain metabolic disorders. * **C. Periosteal reaction:** While common in leukemia (due to subperiosteal infiltration), it is non-specific and can be seen in trauma, osteomyelitis, or Caffey’s disease. * **D. Osteolytic lesions:** These "punched-out" lesions occur in advanced stages due to focal destruction, but they are less characteristic and less frequent than metaphyseal bands. **High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis for Metaphyseal Bands:** Remember the mnemonic **"L-S-C"** (Leukemia, Scurvy, Congenital Syphilis). * **Scurvy vs. Leukemia:** In Scurvy, the radiolucent band is called the *Trummerfeld zone*, but it is accompanied by the *Wimberger ring* and *Pelkan spur*, which helps differentiate it from leukemia. * **Skeletal Pain:** Bone pain in a child that wakes them up at night should always prompt a workup for leukemia, even if the peripheral blood smear is initially normal.

Q: The 'double bubble sign' is typically seen in which of the following conditions?

Annular pancreas. ### Explanation The **'Double Bubble Sign'** is a classic radiological finding on an abdominal X-ray indicating **duodenal obstruction**. It represents air trapped in two distinct dilated compartments: the **stomach** (first bubble) and the **proximal duodenum** (second bubble), with no distal bowel gas. **1. Why Annular Pancreas is Correct:** Annular pancreas occurs due to the failure of the ventral pancreatic bud to rotate properly, resulting in a ring of pancreatic tissue encircling the second part of the duodenum. This causes extrinsic compression and high intestinal obstruction, leading to the characteristic double bubble appearance on imaging. **2. Analysis of Incorrect Options:** * **Ureterocele:** This is a cystic out-pouching of the distal ureter into the urinary bladder. On intravenous pyelogram (IVP), it presents with a **'Cobra-head'** or 'Adder-head' appearance, not a double bubble. * **Hypertrophic Pyloric Stenosis (HPS):** This causes obstruction at the gastric outlet. It typically shows a **'Single Bubble'** (distended stomach) and is associated with the 'String sign' or 'Target sign' on ultrasound. * **Wilm’s Tumour:** A pediatric renal malignancy. It presents as a large abdominal mass that displaces bowel loops but does not typically cause a double bubble sign. **Clinical Pearls for NEET-PG:** * **Differential Diagnosis of Double Bubble:** Duodenal atresia (most common cause), Annular pancreas, Malrotation with Ladd’s bands, and Duodenal web. * **Association:** Duodenal atresia and Annular pancreas are strongly associated with **Down Syndrome (Trisomy 21)**. * **Management:** The surgical treatment of choice for annular pancreas causing obstruction is **Duodenoduodenostomy** (bypassing the obstruction) rather than dividing the pancreatic ring, to avoid pancreatic fistulas.

Q: The "doughnut sign" is characteristically seen in which of the following conditions?

Congenital hypertrophic pyloric stenosis (CHPS). **Explanation:** The **"Doughnut Sign"** (also known as the Target sign) in the context of **Congenital Hypertrophic Pyloric Stenosis (CHPS)** is a classic ultrasonographic finding. It is visualized in the **transverse plane** and is formed by the thickened, hypoechoic ring of the pyloric muscle (the "doughnut") surrounding the echogenic central mucosa. For a diagnosis of CHPS, the pyloric muscle thickness typically exceeds **3 mm** and the pyloric channel length exceeds **14–17 mm**. **Analysis of Options:** * **Intussusception:** While this also presents with a "Target" or "Doughnut" sign on ultrasound, it is formed by layers of bowel-within-bowel. However, in standard radiology examinations, if CHPS is an option, it is the more classic association for the term "Doughnut sign" specifically regarding the pylorus. * **Carcinoma of the Colon:** This typically presents with the **"Apple Core" sign** on a barium enema due to circumferential narrowing of the lumen. * **Volvulus:** Sigmoid volvulus characteristically shows the **"Coffee Bean" sign** or "Omega" sign on an abdominal X-ray. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad of CHPS:** Non-bilious projectile vomiting, palpable "olive-shaped" mass in the epigastrium, and visible gastric peristalsis. * **Metabolic Profile:** Hypochloremic, hypokalemic metabolic alkalosis with paradoxical aciduria. * **Other Signs in CHPS:** "String sign" (narrowed pyloric canal) and "Beak sign" on Barium swallow. * **Treatment of Choice:** Ramstedt’s pyloromyotomy.

Q: What is the imaging modality of choice for neonatal hypertrophic pyloric stenosis?

Ultrasound. **Explanation:** **Ultrasound (USG)** is the gold standard and imaging modality of choice for Neonatal Hypertrophic Pyloric Stenosis (HPS). It is preferred because it is non-invasive, avoids ionizing radiation in neonates, and allows for real-time dynamic visualization of the pylorus. The diagnosis is confirmed by measuring the pyloric muscle thickness and length. **Why the other options are incorrect:** * **X-ray (A):** While it may show a "gasless abdomen" or a dilated stomach with a "single bubble" appearance, it is non-specific and cannot visualize the hypertrophied muscle directly. * **CT Scan (B) & MRI (C):** These are unnecessary, expensive, and time-consuming. CT involves high doses of radiation, while MRI often requires sedation in neonates. Neither offers the real-time benefits of USG for this condition. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** A 3–6 week-old male infant with **non-bilious, projectile vomiting** and a palpable "olive-shaped" mass in the epigastrium. * **Ultrographic Criteria (The "Rule of 3 and 14"):** * Pyloric muscle thickness **>3 mm** (most sensitive). * Pyloric channel length **>14 mm**. * Pyloric diameter **>11 mm**. * **Key Signs:** * **USG:** "Target sign" (transverse) or "Cervix sign" (longitudinal). * **Barium Swallow (if USG is inconclusive):** "String sign," "Beak sign," or "Shoulder sign." * **Metabolic Profile:** Hypochloremic, hypokalemic metabolic alkalosis (Paradoxical aciduria). * **Treatment:** Ramstedt’s Pyloromyotomy (after correcting electrolyte imbalances).

Q: Pneumatosis Intestinalis is associated with which of the following conditions?

Necrotising Enterocolitis. **Explanation:** **Pneumatosis Intestinalis** refers to the presence of gas within the wall of the small or large intestine. It is the pathognomonic radiographic finding for **Necrotizing Enterocolitis (NEC)**, the most common gastrointestinal emergency in neonates (especially premature infants). In NEC, mucosal injury and bacterial invasion lead to gas production (hydrogen and methane) by gas-forming organisms within the bowel wall. * **Option A (Correct):** NEC presents with the triad of abdominal distension, bloody stools, and pneumatosis intestinalis. On X-ray, it appears as linear or curvilinear lucencies outlining the bowel wall. * **Option B:** Gallstone Ileus is characterized by **Rigler’s Triad** (small bowel obstruction, ectopic gallstone, and **pneumobilia**—gas in the biliary tree), not gas in the bowel wall. * **Option C:** Diverticulosis involves outpouchings of the mucosa through the muscularis; while it can lead to pneumoperitoneum if perforated, it is not typically associated with intramural gas. * **Option D:** Hirschsprung Disease presents with distal bowel obstruction and a "transition zone" on contrast enema. While it can lead to enterocolitis (HAEC), the primary radiographic feature is dilated proximal loops and a lack of air in the rectum. **High-Yield Clinical Pearls for NEET-PG:** * **Bell’s Staging:** Used to classify the severity of NEC. * **Portal Venous Gas:** A sign of advanced NEC, indicating gas has migrated from the bowel wall into the mesenteric veins. * **Football Sign:** Indicates massive pneumoperitoneum (perforation), seen as a large oval radiolucency on a supine abdominal X-ray. * **Most common site for NEC:** Terminal ileum and proximal colon.

Q: Which of the following is NOT a cause of respiratory distress in a newborn with ipsilateral shift of the mediastinum?

Hyaline membrane disease. In neonatal radiology, the position of the mediastinum is a critical diagnostic clue. An **ipsilateral shift** (shift toward the side of the pathology) indicates a loss of lung volume or a failure of lung development on that side. ### Why Hyaline Membrane Disease (HMD) is the Correct Answer: **Hyaline Membrane Disease (RDS)** is a diffuse, bilateral condition caused by surfactant deficiency. Radiologically, it presents with bilateral "ground-glass" opacities, air bronchograms, and low lung volumes. Because the pathology is **symmetrical and generalized**, there is no pressure differential between the hemithoraces; therefore, the mediastinum remains **central**. ### Why the Other Options are Incorrect: * **Atelectasis & B. Lung Collapse:** Both involve the loss of air in a portion of or the entire lung. This creates negative pressure on the affected side, "pulling" the mediastinum toward the lesion (**ipsilateral shift**). * **Pulmonary Hypoplasia:** This is the incomplete development of the lung. The resulting empty space in the thoracic cavity causes the mediastinum to shift toward the underdeveloped side (**ipsilateral shift**) to compensate for the volume deficit. ### NEET-PG High-Yield Pearls: * **Ipsilateral Shift (Pull):** Think volume loss (Atelectasis, Agenesis, Hypoplasia, Post-pneumonectomy). * **Contralateral Shift (Push):** Think volume addition (Tension Pneumothorax, Massive Pleural Effusion, Congenital Diaphragmatic Hernia, CPAM). * **HMD Key Sign:** "Ground-glass" appearance + Air bronchograms + Central mediastinum. * **Congenital Diaphragmatic Hernia (CDH):** Most common cause of a **contralateral** shift in a distressed neonate with a scaphoid abdomen.

Q: A patient presented to the OPD with a sudden onset of shortness of breath. Identify the condition with the radiological image given below.

Laryngotracheobronchitis. ***Laryngotracheobronchitis*** - The AP neck radiograph displays the classic **"steeple sign,"** which is a tapered narrowing of the subglottic trachea (indicated by the arrow) due to inflammation. - This condition, also known as **croup**, is typically caused by a viral infection (most commonly **parainfluenza virus**) and presents with a characteristic **barking cough** and inspiratory stridor. *Epiglottitis* - This condition is characterized by the **"thumb sign"** on a *lateral* neck X-ray, which shows a swollen epiglottis, not the subglottic narrowing seen here. - Patients typically present more severely with high fever, **drooling**, dysphagia, and assume a **"tripod" posture**, which differs from the presentation of croup. *Bronchitis* - Bronchitis is an inflammation of the larger airways (bronchi) and would not produce findings in the subglottic region of a neck X-ray. - The primary symptom is a productive cough, and a **chest X-ray**, not a neck X-ray, would be the relevant imaging, which is often normal. *Laryngomalacia* - This is a congenital condition causing inspiratory stridor due to the collapse of soft laryngeal structures; it is not an acute infectious process. - The diagnosis is typically confirmed with **flexible laryngoscopy**, and plain radiographs are usually normal and do not show a steeple sign.

Q: A school-aged child undergoes chest radiography for recurrent respiratory infections. The radiograph shows multiple variably sized, thin-walled, air-filled cystic spaces confined predominantly to the left lung. The left hemidiaphragm is intact, and there are no bowel loops within the thorax. What is the most likely diagnosis?

Congenital pulmonary airway malformation (CPAM). The clustered, variably sized air-filled cysts within the left lung are most consistent with congenital pulmonary airway malformation, particularly a macrocystic lesion. CPAM is a developmental abnormality of the lower respiratory tract that may present after infancy with recurrent respiratory infections. Congenital diaphragmatic hernia is unlikely because the diaphragm is intact and no intrathoracic bowel loops are seen. Congenital lobar emphysema typically causes homogeneous lobar hyperinflation rather than multiple discrete cysts, while postinfectious pneumatoceles require an appropriate acute infectious history and are usually transient.

Question 1

What is the most characteristic radiographic sign in a child with leukemia?

Accepted Answer

Metaphyseal translucencies

Answer

Osteosclerosis of the metaphysis

Answer

Periosteal reaction

Answer

Osteolytic lesion

Question 2

Time sector scanning of neonates is preferred because of which of the following reasons?

Accepted Answer

Open fontanelles

Answer

Inexpensive

Answer

Children are more cooperative

Answer

Better resolution

Question 3

What is the best diagnostic investigation for acute appendicitis in children?

Accepted Answer

USG

Answer

MRI

Answer

CECT

Answer

X-ray

Question 4

The 'double bubble sign' is typically seen in which of the following conditions?

Accepted Answer

Annular pancreas

Answer

Ureterocele

Answer

Hypertrophic pyloric stenosis

Answer

Wilm's tumour

Question 5

The "doughnut sign" is characteristically seen in which of the following conditions?

Accepted Answer

Congenital hypertrophic pyloric stenosis (CHPS)

Answer

Intussusception

Answer

Carcinoma of the colon

Answer

Volvulus

Question 6

What is the imaging modality of choice for neonatal hypertrophic pyloric stenosis?

Accepted Answer

Ultrasound

Answer

X-ray

Answer

CT scan

Answer

MRI

Question 7

Pneumatosis Intestinalis is associated with which of the following conditions?

Accepted Answer

Necrotising Enterocolitis

Answer

Gall Stone Ileus

Answer

Diverticulosis

Answer

Hirschsprung Disease

Question 8

Which of the following is NOT a cause of respiratory distress in a newborn with ipsilateral shift of the mediastinum?

Accepted Answer

Hyaline membrane disease

Answer

Atelectasis

Answer

Lung collapse

Answer

Pulmonary hypoplasia

Question 9

A patient presented to the OPD with a sudden onset of shortness of breath. Identify the condition with the radiological image given below.

Accepted Answer

Laryngotracheobronchitis

Answer

Epiglottitis

Answer

Bronchitis

Answer

Laryngomalacia

Question 10

A school-aged child undergoes chest radiography for recurrent respiratory infections. The radiograph shows multiple variably sized, thin-walled, air-filled cystic spaces confined predominantly to the left lung. The left hemidiaphragm is intact, and there are no bowel loops within the thorax. What is the most likely diagnosis?

Accepted Answer

Congenital pulmonary airway malformation (CPAM)

Answer

Congenital lobar emphysema

Answer

Congenital diaphragmatic hernia

Answer

Pneumatocele formation from pneumonia

Pediatric Radiology — MCQs

Pediatric Radiology — MCQs

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