Pediatric Radiology Practice Questions

Q: Radiological hallmark of primary tuberculosis in childhood is?

Lymphadenopathy. ***Lymphadenopathy*** - Primary tuberculosis in children distinctively presents with **enlarged hilar and mediastinal lymph nodes** as a hallmark radiological finding. - This is often a result of the immune response to the primary infection in the lungs, leading to inflammation and swelling of regional lymph nodes. *Ghon's focus* - A **Ghon's focus** refers to the initial lung parenchymal lesion formed during primary tuberculosis, but it is typically small and often not the most prominent or defining radiological feature in childhood. - While it is a part of the primary complex, **lymphadenopathy** is generally considered the more striking and consistent radiological hallmark. *Normal chest Xray* - A **normal chest X-ray** is unlikely in a child with active primary tuberculosis, as the infection almost always produces detectable changes. - While some cases might be very mild, the presence of disease usually leads to visible radiological abnormalities. *Pleural effusion* - **Pleural effusion** can occur in primary tuberculosis, but it is a complication or a manifestation that typically develops later, rather than being the defining initial hallmark. - It indicates the spread of infection to the pleural space, often seen in more advanced or symptomatic cases.

Q: True about hypertrophic pyloric stenosis on ultrasound

Muscle thickness greater than 4mm on ultrasound. ***Muscle thickness greater than 4mm on ultrasound*** - A **pyloric muscle thickness of 4 mm or more** is the **primary quantitative diagnostic criterion** for hypertrophic pyloric stenosis on ultrasound. - This measurement provides **objective, reproducible** assessment and is the most reliable parameter for diagnosis. - Increased muscle thickness leads to luminal narrowing and gastric outlet obstruction. *Target sign appearance on ultrasound* - The "target sign" or "donut sign" **is indeed seen** in hypertrophic pyloric stenosis and represents the **concentric layers** of thickened pyloric muscle and mucosa on transverse view. - However, it is a **qualitative, descriptive finding** rather than a specific diagnostic measurement. - While characteristic, it is **less specific** than quantitative measurements and can occasionally be seen in other conditions with pyloric wall thickening. - The target sign indicates presence of pyloric abnormality but requires **measurement confirmation** for definitive diagnosis. *Pyloric channel length greater than 15mm on ultrasound* - A **pyloric channel length of 16-17 mm or more** is the accepted diagnostic criterion for hypertrophic pyloric stenosis. - A measurement of **15mm is borderline** and falls just below the diagnostic threshold, making it insufficient for definitive diagnosis. - While length is increased in HPS, this specific cutoff is not diagnostic. *Muscle thickness less than 3mm on ultrasound* - A pyloric muscle thickness **less than 3mm** is considered within the **normal range** for infants and effectively rules out hypertrophic pyloric stenosis. - HPS is characterized by significant **muscle hypertrophy** (≥3-4mm), making this option clearly incorrect.

Q: The 'figure of eight' appearance on chest X-ray is commonly seen in which congenital heart defect?

Total anomalous pulmonary venous connection (TAPVC). ***Total anomalous pulmonary venous connection (TAPVC)*** - The "figure of eight" or "snowman" appearance on a chest X-ray is characteristic of **supracardiac TAPVC**. - This occurs due to the **dilated superior vena cava (SVC)** forming the "head" and the dilated right atrium and ventricle forming the "body" of the snowman. *Transposition of the great arteries* - The classic chest X-ray finding for this condition is a **"egg on a string"** appearance, where the narrow mediastinum gives the impression of an egg-shaped heart. - This is due to the **aorta** lying directly anterior to the **pulmonary artery**, obscuring their usual normal configuration. *Ebstein's anomaly* - Characterized by **apical displacement of the tricuspid valve leaflets**, leading to a large atrialized right ventricle. - Chest X-ray often shows a **markedly enlarged heart** (cardiomegaly) due to right atrial and right ventricular dilation, but not a "figure of eight" pattern. *Tetralogy of Fallot* - The classic chest X-ray finding for Tetralogy of Fallot is a **"boot-shaped" heart** (coeur en sabot). - This shape is due to **right ventricular hypertrophy** and an upturned apex, along with a concave pulmonary artery segment.

Q: What is indicated by the 'double bubble sign' on prenatal ultrasound?

Duodenal atresia. ***Duodenal atresia*** - The **double bubble sign** on prenatal ultrasound is pathognomonic for **duodenal atresia**, representing a dilated stomach and a dilated first part of the duodenum. - This congenital anomaly results from a failure of the **duodenal lumen** to recanalize during fetal development, leading to a complete obstruction. *Hirschsprung disease* - Characterized by the absence of **ganglion cells** in the distal colon, leading to functional obstruction, but it does not typically present as a **double bubble sign** on prenatal ultrasound. - While it can cause bowel dilation, it usually affects more distal portions of the bowel and presents with symptoms like **delayed meconium passage** postnatally. *Pyloric stenosis* - Involves hypertrophy of the **pyloric muscle**, leading to gastric outlet obstruction, but it typically presents in infancy with **non-bilious projectile vomiting** and an **olive-shaped mass**, not a double bubble sign antenatally. - The 'double bubble' is specific to obstructions *after* the pylorus, in the duodenum. *Esophageal atresia* - This condition involves a blind-ending esophagus and is often associated with a **tracheoesophageal fistula**, leading to symptoms like **frothing and bubbling at the mouth** and choking during feeds. - While it impacts feeding, it does not cause the characteristic appearance of a **dilated stomach** and duodenum seen in the double bubble sign.

Q: What is the first-line imaging modality for the evaluation of pyloric stenosis in infants?

Ultrasound. ***Ultrasound*** - **Ultrasound** is the preferred first-line imaging modality due to its **non-invasive nature**, lack of radiation, and high accuracy in diagnosing pyloric stenosis. - It allows direct visualization and measurement of the **pyloric muscle thickness** and length, which are key diagnostic criteria. *X-ray* - While an initial **X-ray** might be performed to rule out other causes of vomiting, it is generally **not definitive** for diagnosing pyloric stenosis. - It may show a **dilated stomach** but cannot visualize the pyloric muscle directly. *CT scan* - A **CT scan** is not the first-line imaging choice due to the **radiation exposure**, which should be minimized in infants. - It offers more detailed anatomical information but is **not necessary** for the diagnosis of pyloric stenosis, given the effectiveness of ultrasound. *MRI* - **MRI** is not routinely used for diagnosing pyloric stenosis because it is **time-consuming**, expensive, and often requires sedation in infants. - It provides excellent soft tissue contrast, but its benefits **do not outweigh the drawbacks** for this specific condition compared to ultrasound.

Q: Which of the following is the most appropriate initial imaging study for a child with suspected pyloric stenosis?

Ultrasound. ***Correct: Ultrasound*** **Ultrasound** is the preferred initial imaging modality for suspected **pyloric stenosis** due to its high diagnostic accuracy, non-invasive nature, and lack of radiation exposure. It allows for direct visualization and measurement of the **pyloric muscle thickness** (>3 mm diagnostic) and **length** (>15 mm diagnostic), which are key diagnostic criteria. Real-time assessment can also demonstrate the "pyloric muscle doughnut sign" and failure of gastric contents to pass through the pylorus. *Incorrect: Barium swallow* While a **barium swallow** can show a "string sign" or "double-track sign" indicative of pyloric stenosis, it is less preferred than ultrasound due to **radiation exposure** and potential for aspiration in infants with frequent vomiting. It is typically considered only if ultrasound results are equivocal or unavailable. *Incorrect: CT scan* A **CT scan** is generally not indicated for the diagnosis of pyloric stenosis due to significant **radiation exposure** (particularly concerning in infants) and its inability to provide real-time dynamic imaging of the pylorus. It offers no diagnostic advantage over ultrasound for this condition and involves unnecessary risks. *Incorrect: MRI* **MRI** provides excellent soft tissue contrast but is not the initial imaging choice for pyloric stenosis because it is more time-consuming, expensive, and often requires **sedation** in infants. The logistical challenges and lack of additional diagnostic benefit compared to ultrasound make it impractical as a first-line investigation.

Q: Which imaging modality is most commonly used to diagnose ectopic kidneys in children?

Ultrasound. ***Ultrasound*** - **Ultrasound** is the initial and most commonly used imaging modality due to its non-invasive nature, accessibility, and ability to visualize renal anatomy and location without radiation exposure. - It can effectively identify the **presence and location of ectopic kidneys**, as well as associated anomalies like hydronephrosis. *DTPA scan* - A **DTPA (diethylenetriamine pentaacetic acid) scan** primarily evaluates **renal function and blood flow** and is less detailed for anatomical localization. - While it can show renal perfusion, it is not the primary diagnostic tool for initial anatomical diagnosis of an ectopic kidney. *DMSA scan* - A **DMSA (dimercaptosuccinic acid) scan** is used to assess **renal cortical scarring and function**, particularly in cases of pyelonephritis. - It provides functional information about the kidney but is not typically the first-line imaging for identifying the anatomical location of an ectopic kidney. *MAG3 scan* - A **MAG3 (mercaptoacetyltriglycine) scan** assesses **renal plasma flow and excretory function**, similar to DTPA but often preferred in cases of impaired renal function. - It is more functional than anatomical in nature and less suitable as a primary tool for diagnosing ectopic kidney location compared to ultrasound.

Q: In the following X-ray of the wrist (image provided), what is the exact age of the child?

6 yrs. ***6 yrs*** - In a standard **wrist X-ray for bone age assessment**, around age 6, the **distal epiphysis of the ulna** typically becomes well-ossified. - The appearance of the **pisiform bone**, which ossifies consistently around 6 to 7 years old, is also a key indicator. The image shows the pisiform bone as a distinct ossification center. *2 yrs* - At 2 years, only the **capitate** and **hamate** carpal bones would be ossified, and the **distal ulna epiphysis** would not yet be clearly visible or well-ossified. - The other carpal bones like the triquetrum, lunate, and scaphoid would either be absent or just beginning to appear as faint ossification centers. *8 yrs* - By 8 years, nearly all carpal bones, including the **trapezium** and **trapezoid**, would be well ossified. - The **epiphyses of the distal radius and ulna** would be much more mature and closer to fusing, showing a more advanced stage of skeletal development. *9 yrs* - At 9 years, the bone age would be even more advanced, with the **epiphyseal growth plates** becoming narrower and indicating closer proximity to skeletal maturity. - All carpal bones would be clearly visible and well-defined, and the **trapezium** and **trapezoid** would typically be similar in size and maturity to the scaphoid.

Q: Steeple sign is seen in which of the following conditions?

Acute laryngotracheobronchitis. ***Acute laryngotracheobronchitis*** - The **steeple sign** on an anteroposterior (AP) neck radiograph is a classic finding in acute laryngotracheobronchitis, also known as **croup**. - This sign refers to the **subglottic narrowing** of the trachea, resembling a church steeple, due to edema caused by viral infection. *Acute epiglottitis* - Acute epiglottitis is characterized by the **thumb sign** on a lateral neck radiograph, where the swollen epiglottis appears enlarged. - This condition involves inflammation primarily of the epiglottis, not the subglottic region. *Laryngeal papillomatosis* - Laryngeal papillomatosis is characterized by **wart-like growths** (papillomas) on the vocal cords and larynx, often leading to hoarseness. - Radiographically, it typically appears as irregular soft tissue masses, not the diffuse subglottic narrowing seen in croup. *Bilateral abductor paralysis* - Bilateral abductor paralysis involves the inability of both vocal cords to abduct, leading to a **fixed, narrowed glottic opening**. - This condition presents as a smooth, constant narrowing at the level of the vocal cords rather than the subglottic, conical narrowing of the steeple sign.

Q: Which of the following is NOT a typical ultrasonographic finding in autosomal recessive polycystic kidney disease (ARPKD)?

Cysts larger than 2 cm. **Cysts larger than 2 cm** - **ARPKD** is characterized by numerous tiny cysts (typically 1-2 mm, rarely up to 1 cm) that are microscopically dilated collecting ducts, leading to diffuse renal enlargement. - Cysts larger than 2 cm are much more typical of **autosomal dominant polycystic kidney disease (ADPKD)**, which involves macroscopic cysts of various sizes. *Enlarged kidneys* - The proliferation of dilated collecting ducts and associated interstitial fibrosis in **ARPKD** leads to significantly enlarged kidneys, which is a hallmark ultrasound finding. - This enlargement is often bilateral and can be detected prenatally or in neonates. *Increased echogenicity* - The presence of numerous tiny cysts and dense fibrous tissue throughout the renal parenchyma in **ARPKD** causes increased diffuse echogenicity on ultrasound. - This is a common and important diagnostic feature, often described as "bright" or "hyperechoic" kidneys. *Corticomedullary differentiation is lost* - In **ARPKD**, the normal distinct differentiation between the renal cortex and medulla is obliterated due to the widespread involvement of the collecting ducts and the diffuse nature of the disease. - This loss of corticomedullary differentiation is a typical finding on ultrasound for severe renal parenchymal disease, including ARPKD.

Question 1

Radiological hallmark of primary tuberculosis in childhood is?

Accepted Answer

Lymphadenopathy

Answer

Ghon's focus

Answer

Normal chest Xray

Answer

Pleural effusion

Question 2

True about hypertrophic pyloric stenosis on ultrasound

Accepted Answer

Muscle thickness greater than 4mm on ultrasound

Answer

Target sign appearance on ultrasound

Answer

Pyloric channel length greater than 15mm on ultrasound

Answer

Muscle thickness less than 3mm on ultrasound

Question 3

The 'figure of eight' appearance on chest X-ray is commonly seen in which congenital heart defect?

Accepted Answer

Total anomalous pulmonary venous connection (TAPVC)

Answer

Transposition of the great arteries

Answer

Ebstein's anomaly

Answer

Tetralogy of Fallot

Question 4

What is indicated by the 'double bubble sign' on prenatal ultrasound?

Accepted Answer

Duodenal atresia

Answer

Hirschsprung disease

Answer

Pyloric stenosis

Answer

Esophageal atresia

Question 5

What is the first-line imaging modality for the evaluation of pyloric stenosis in infants?

Accepted Answer

Ultrasound

Answer

X-ray

Answer

CT scan

Answer

MRI

Question 6

Which of the following is the most appropriate initial imaging study for a child with suspected pyloric stenosis?

Accepted Answer

Ultrasound

Answer

Barium swallow

Answer

CT scan

Answer

MRI

Question 7

Which imaging modality is most commonly used to diagnose ectopic kidneys in children?

Accepted Answer

Ultrasound

Answer

DTPA scan

Answer

MAG3 scan

Answer

DMSA scan

Question 8

In the following X-ray of the wrist (image provided), what is the exact age of the child?

Accepted Answer

6 yrs

Answer

2 yrs

Answer

8 yrs

Answer

9 yrs

Question 9

Steeple sign is seen in which of the following conditions?

Accepted Answer

Acute laryngotracheobronchitis

Answer

Acute epiglottitis

Answer

Laryngeal papillomatosis

Answer

Bilateral abductor paralysis

Question 10

Which of the following is NOT a typical ultrasonographic finding in autosomal recessive polycystic kidney disease (ARPKD)?

Accepted Answer

Cysts larger than 2 cm

Answer

Increased echogenicity

Answer

Enlarged kidneys

Answer

Corticomedullary differentiation is lost

Pediatric Radiology — MCQs

Pediatric Radiology — MCQs

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