Pediatric Radiology Practice Questions

Q: What condition is indicated by the double bubble sign on an abdominal X-ray?

Duodenal atresia. ***Duodenal atresia*** - The **double bubble sign** on an abdominal X-ray is pathognomonic for **duodenal atresia**, characterized by two air-filled bubbles: one in the stomach and one in the proximal duodenum, separated by the pylorus. - This congenital anomaly results from a complete obstruction of the duodenum, preventing the passage of air and fluid past this point. *Duodenal stenosis* - While also an obstruction of the duodenum, **duodenal stenosis** is an incomplete obstruction, meaning some gas will pass beyond the duodenum. - This would result in gas being present in the distal bowel, which is not seen with a classic "double bubble" where the bowel distal to the duodenum is gasless. *Volvulus* - **Volvulus** involves the twisting of a loop of intestine, leading to obstruction and potentially ischemia. - While it can cause obstruction, it typically presents with a "corkscrew" appearance on an upper GI series or signs of diffuse bowel distension, not the isolated double bubble. *All of the options* - The double bubble sign is highly specific to **duodenal atresia** due to the complete obstruction it signifies. - Other conditions like duodenal stenosis and volvulus cause different radiological patterns, making this option incorrect.

Q: In which condition is the 'double bubble sign' typically observed?

Duodenal atresia. ***Duodenal atresia*** - The **'double-track sign'**, also known as the **'double bubble sign'**, is a classic radiographic finding in duodenal atresia. It represents the dilation of the **stomach** and the **proximal duodenum**, separated by the pylorus. - This sign indicates an obstruction at or distal to the level of the ampulla of Vater, preventing the passage of air and fluid into the more distal small bowel. *Gastric ulcer* - Gastric ulcers are mucosal erosions in the stomach lining and are typically diagnosed via **endoscopy** or barium studies. - They do not cause the specific anatomical configuration that leads to a 'double track sign'. *Achalasia* - Achalasia is a motility disorder of the esophagus characterized by the failure of the lower esophageal sphincter to relax and a loss of peristalsis in the esophageal body. - Radiographically, it's often associated with a **'bird's beak' appearance** of the distal esophagus, not a 'double track sign'. *Congenital hypertrophic pyloric stenosis (CHPS)* - CHPS involves thickening of the pyloric muscle, which obstructs gastric emptying. The classic radiographic finding is the **'string sign'** (contrast material thinly stringing through the narrowed pylorus) or the **'shoulder sign'** on ultrasound. - While it causes gastric outlet obstruction, it affects the pylorus itself rather than creating two separate dilated segments like in duodenal atresia.

Q: A postnatal X-ray of the abdomen of a neonate shows a "double bubble sign". It is seen with:

Duodenal atresia. **Duodenal atresia** - The **"double bubble sign"** on an abdominal X-ray is classic for **duodenal atresia**, representing a dilated stomach and a dilated proximal duodenum separated by the pylorus. - This finding indicates a complete obstruction at the level of the duodenum, preventing the passage of gas distally. *Ileal atresia (may show distension throughout the bowel)* - In **ileal atresia**, the obstruction is further down the small bowel, leading to multiple dilated loops of bowel proximal to the atresia. - The X-ray would typically show more widespread **abdominal distension** with multiple air-fluid levels rather than the distinct double bubble. *Pyloric stenosis (typically presents with a single bubble sign)* - **Pyloric stenosis** involves narrowing of the pylorus but not an complete obstruction in the same way as duodenal atresia, leading to gastric outlet obstruction. - While it might show a **distended stomach (single bubble)**, it typically does not obstruct distally enough to create a second prominent bubble in the duodenum. *Esophageal atresia (associated with airless abdomen on X-ray)* - **Esophageal atresia** is an interruption in the continuity of the esophagus, preventing swallowed air from reaching the stomach and intestines. - An abdominal X-ray in this condition would typically show an **airless abdomen** because air cannot pass into the gastrointestinal tract.

Q: What is the investigation of choice for acute appendicitis in children?

USG. ***USG*** - **Ultrasound** (USG) is the preferred initial imaging modality due to its **non-invasive nature** and **lack of radiation exposure**, which is particularly important in children. - It can effectively visualize the **appendix**, assess its compressibility, and identify signs of inflammation like wall thickening and pericecal fluid collection. *MRI* - **MRI** is a highly accurate imaging technique for appendicitis but is generally reserved for cases where USG is inconclusive, or when there is a need to avoid radiation, and USG is not sufficient. - It takes **longer to perform** and often requires **sedation** in younger children, making it less practical as a first-line investigation. *CT scan* - **CT scan** is very sensitive and specific for appendicitis but involves significant **ionizing radiation**, which is a concern in the pediatric population due to increased lifetime cancer risk. - While it provides detailed anatomical information, the **radiation exposure** makes it a second-line investigation for children, typically used when USG is inconclusive or appendicitis is strongly suspected despite negative USG. *X-ray* - A plain **abdominal X-ray** has **very limited utility** in diagnosing acute appendicitis as it cannot visualize the appendix directly. - It may show non-specific findings like a **fecalith** or **ileus**, but these are not diagnostic of appendicitis and can be found in other conditions.

Q: Double bubble sign is seen in -

All of the options. ***All of the options*** - The **"double bubble sign"** on an X-ray indicates **duodenal obstruction**, which can be caused by intrinsic factors like **duodenal atresia** or extrinsic compressions such as an **annular pancreas** or **Ladd's bands** associated with malrotation. - While differing in etiology, all these conditions lead to fluid and air accumulation in the stomach and proximal duodenum, creating the characteristic two dilated loops. *Duodenal atresia* - This is an **intrinsic congenital obstruction** of the duodenum, preventing the passage of gastric and duodenal contents. - On imaging, it shows **two distinct air-filled bubbles** (one for the stomach, one for the proximal duodenum) separated by the pylorus. *Ladd's band* - **Ladd's bands** are peritoneal fibrous bands that can compress the duodenum in cases of **intestinal malrotation**, leading to extrinsic obstruction. - The resulting proximal duodenal dilation, along with gastric distension, presents as the **double bubble sign**. *Annular pancreas* - An **annular pancreas** is a congenital anomaly where pancreatic tissue completely encircles and obstructs the second part of the duodenum. - This extrinsic compression causes significant dilation of the stomach and proximal duodenum, mimicking the appearance of the **double bubble sign**.

Q: What is the most likely diagnosis of a child with the following chest X-ray finding (image required)?

Tetralogy of Fallot (TOF). ***TOF*** - The classic chest X-ray finding in **Tetralogy of Fallot** is a **boot-shaped heart** ("coeur en sabot") due to right ventricular hypertrophy and a concave pulmonary artery segment. The image provided would show this characteristic configuration. - This morphology is a result of the four defects: **ventricular septal defect (VSD)**, **pulmonary stenosis**, **overriding aorta**, and **right ventricular hypertrophy**. *Transposition of Great Arteries (TGA)* - TGA typically presents with a **"egg-on-a-string"** or **"egg-on-side" appearance** on chest X-ray, characterized by a narrow upper mediastinum (due to parallel great arteries) and cardiomegaly. - This is due to the **aorta arising from the right ventricle** and the **pulmonary artery from the left ventricle**, leading to two separate circulations. *Total Anomalous Pulmonary Venous Connection (TAPVC)* - TAPVC, particularly the supracardiac type, often presents with a **"snowman" or "figure-of-8" heart** on chest X-ray, caused by the dilated vertical vein and superior vena cava draining into the right atrium. - This anomaly involves all **four pulmonary veins draining abnormally**, typically into the systemic circulation. *Ebstein's Anomaly* - Ebstein's anomaly is characterized by a **massively enlarged right atrium** and **cardiomegaly** on chest X-ray, often described as a **"box-shaped" heart**, due to the apical displacement of the tricuspid valve. - This condition involves the **tricuspid valve being displaced into the right ventricle**, leading to atrialization of a portion of the right ventricle.

Q: Investigation of choice for the diagnosis of congenital hypertrophic pyloric stenosis is:

USG. ***USG*** - **Ultrasound** is the preferred initial imaging modality due to its non-invasiveness, lack of radiation, and high accuracy in visualizing the thickened pyloric muscle. - The classic ultrasound findings include a **pyloric muscle thickness** of ≥ 4 mm and a **pyloric channel length** of ≥ 14 mm. *Barium meal* - While a barium meal can show findings like the "string sign" or "shoulder sign," it involves **radiation exposure** and is generally considered a second-line investigation. - Its diagnostic accuracy is good, but it is less convenient and riskier than ultrasound for this condition. *Barium meal follow through* - This procedure tracks barium through the entire gastrointestinal tract, which is **excessive and unnecessary** for diagnosing pyloric stenosis, which is a localized obstruction. - It also involves significant **radiation exposure** and a prolonged examination time. *CT scan with contrast* - A **CT scan** involves significant **radiation exposure** and is not typically used for diagnosing congenital hypertrophic pyloric stenosis. - It is also less sensitive than ultrasound for visualizing the specific soft tissue changes in the pyloric muscle.

Q: Investigation of choice for hypertrophic pyloric stenosis is

USG. ***USG*** - **Ultrasound** is the preferred imaging modality for diagnosing **hypertrophic pyloric stenosis** due to its non-invasive nature, lack of radiation, and ability to directly visualize the thickened pyloric muscle. - Diagnostic criteria on ultrasound include a **pyloric muscle thickness** greater than 3-4 mm and a **pyloric channel length** greater than 14-17 mm. *X-ray* - An **X-ray** may show a dilated stomach with a **small amount of gas** in the distal bowel, but it is not specific for hypertrophic pyloric stenosis and cannot directly visualize the pylorus. - Barium studies (upper GI series) were historically used but have largely been replaced by ultrasound due to **radiation exposure** and diagnostic inferiority. *CT* - **CT scans** involve significant **radiation exposure** and are generally not recommended for infants due to risks, especially when a definitive diagnosis can be made effectively with ultrasound. - While CT can visualize the pylorus, it offers no significant advantage over ultrasound for this specific condition and carries **higher risks**. *MRI* - **MRI** is a sophisticated imaging technique that offers excellent soft tissue contrast, but it is **time-consuming**, expensive, and often requires sedation in infants. - It is not the investigation of choice for hypertrophic pyloric stenosis where **ultrasound is readily available** and provides sufficient diagnostic information without sedation or radiation.

Q: What is the investigation of choice for an 8-year-old child presenting with an acute abdomen?

USG. ***USG*** - An **ultrasound (USG)** is the preferred initial imaging modality in pediatric acute abdomen due to its **lack of ionizing radiation**, ease of use, and ability to visualize common causes like appendicitis and intussusception. - It is particularly useful for assessing **fluid collections**, inflammation, and obstruction in a non-invasive manner suitable for children. *CT Scan* - While it offers detailed anatomical views, **CT scans** involve significant **ionizing radiation**, which is a concern in children due to increased lifetime cancer risk. - It is typically reserved for cases where **USG is inconclusive** or if there is a high suspicion of conditions not well visualized by ultrasound. *X-ray* - **X-rays** provide limited information for soft tissue pathologies and are primarily useful for detecting **bowel obstruction (air-fluid levels)** or **free air** (perforation). - They lack the resolution to diagnose many common causes of acute abdomen in children, such as appendicitis or intussusception. *MRI* - **MRI** provides excellent soft tissue contrast without ionizing radiation but often requires **sedation** in young children due to the long scan times and need for stillness. - It is less readily available and more expensive than USG, making it a less practical first-line investigation for an acute presentation.

Q: What is the cardiothoracic ratio in children?

50-55%. ***50-55%*** - The normal **cardiothoracic ratio** in children is generally considered to be **50-55%** on a **posterior-anterior (PA) chest X-ray**. - In **infants and young children (under 2 years)**, the ratio can be **up to 55-60%** due to relatively larger cardiac size and more horizontal positioning of the heart. - In **older children (over 2 years)**, the normal ratio approaches adult values of **less than 50%**. - A ratio consistently greater than 55% could indicate **cardiomegaly**, which warrants further investigation. *30-35%* - This range is typically too low and would suggest an **unusually small heart** for the chest cavity, which is not a normal finding in children. - A very low ratio like this is not characteristic of the pediatric population and may indicate technical issues with the radiograph. *40-45%* - While this range approaches normal values for **older children and adults**, it is generally on the lower side for the average **pediatric cardiothoracic ratio**. - This percentage alone is not the best answer when considering the entire pediatric age spectrum, including infants and younger children. *60-65%* - A cardiothoracic ratio in this range would typically be considered **abnormal** and indicative of **cardiomegaly** in children beyond infancy. - Such an elevated ratio would suggest an enlarged heart, prompting further cardiac evaluation including **echocardiography** to assess for structural heart disease.

Question 1

What condition is indicated by the double bubble sign on an abdominal X-ray?

Accepted Answer

Duodenal atresia

Answer

Duodenal stenosis

Answer

Volvulus

Answer

All of the options

Question 2

In which condition is the 'double bubble sign' typically observed?

Accepted Answer

Duodenal atresia

Answer

Gastric ulcer

Answer

Achalasia

Answer

Congenital hypertrophic pyloric stenosis (CHPS)

Question 3

A postnatal X-ray of the abdomen of a neonate shows a "double bubble sign". It is seen with:

Accepted Answer

Duodenal atresia

Answer

Ileal atresia

Answer

Pyloric stenosis

Answer

Esophageal atresia

Question 4

What is the investigation of choice for acute appendicitis in children?

Accepted Answer

USG

Answer

MRI

Answer

CT scan

Answer

X-ray

Question 5

Double bubble sign is seen in -

Accepted Answer

All of the options

Answer

Duodenal atresia

Answer

Annular pancreas

Answer

Ladd's band

Question 6

What is the most likely diagnosis of a child with the following chest X-ray finding (image required)?

Accepted Answer

Tetralogy of Fallot (TOF)

Answer

Transposition of Great Arteries (TGA)

Answer

Total Anomalous Pulmonary Venous Connection (TAPVC)

Answer

Ebstein's Anomaly

Question 7

Investigation of choice for the diagnosis of congenital hypertrophic pyloric stenosis is:

Accepted Answer

USG

Answer

Barium meal

Answer

Barium meal follow through

Answer

CT scan with contrast

Question 8

Investigation of choice for hypertrophic pyloric stenosis is

Accepted Answer

USG

Answer

X-ray

Answer

CT

Answer

MRI

Question 9

What is the investigation of choice for an 8-year-old child presenting with an acute abdomen?

Accepted Answer

USG

Answer

CT Scan

Answer

X-ray

Answer

MRI

Question 10

What is the cardiothoracic ratio in children?

Accepted Answer

50-55%

Answer

30-35%

Answer

40-45%

Answer

60-65%

Pediatric Radiology — MCQs

Pediatric Radiology — MCQs

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