Pediatric Radiology Practice Questions

Q: The "triangular cord sign" on ultrasonography is indicative of which condition in a neonate?

Biliary atresia. **Explanation:** The **triangular cord sign** is a highly specific ultrasonographic finding for **Biliary Atresia (BA)**. It represents a cone-shaped or triangular fibrotic mass of the cranial part of the extrahepatic biliary tree. On ultrasound, it appears as an echogenic (hyperechoic) area located anterior to the bifurcation of the portal vein. A thickness of **>4 mm** is generally considered diagnostic. **Why Biliary Atresia is correct:** In BA, there is progressive fibro-obliterative destruction of the extrahepatic biliary system. The "triangular cord" is the sonographic visualization of this fibrous remnant at the porta hepatis. When combined with an absent or small, irregular gallbladder (ghost gallbladder sign), it is a pathognomonic finding. **Why other options are incorrect:** * **Galactosemia:** This is a metabolic disorder. While it can cause neonatal jaundice and hepatomegaly, it does not involve anatomical obliteration of the bile ducts; diagnosis is via enzyme assays and urine reducing sugars. * **Hepatitis (Neonatal):** This is the primary differential for BA. On ultrasound, neonatal hepatitis typically shows a patent biliary tree and a normal-sized gallbladder. It lacks the specific fibrous cord seen in BA. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Intraoperative Cholangiogram (IOCG). * **Best Initial Screening:** Ultrasound (looking for the triangular cord sign). * **Functional Imaging:** HIDA scan (shows uptake by the liver but **no excretion** into the bowel even after 24 hours). * **Surgical Management:** Kasai Procedure (Hepatoportoenterostomy), ideally performed before 60 days of life. * **Liver Biopsy:** Shows bile duct proliferation and portal fibrosis.

Q: An X-ray of a neonate's abdomen reveals which of the following findings?

Pneumatosis intestinalis. ***Pneumatosis intestinalis*** - Appears as **linear or cystic gas collections** within the bowel wall on X-ray, indicating **necrotizing enterocolitis (NEC)**. - Often accompanied by **portal venous gas** and **pneumoperitoneum** in severe cases, representing bowel wall necrosis. *Duodenal atresia* - Characterized by the classic **"double bubble" sign** with **gastric and duodenal distension** only. - Shows **absence of distal bowel gas** due to complete obstruction at the duodenum. *Jejunal atresia* - Presents with **"triple bubble" sign** or **multiple dilated bowel loops** proximal to the obstruction. - Shows **minimal to absent distal bowel gas** with dilated proximal small bowel loops. *Hirschsprung's disease* - Demonstrates **dilated proximal colon** with **narrow distal rectosigmoid segment** creating a **transition zone**. - Shows **retained stool** in dilated bowel with **absence of normal rectal gas shadow**.

Q: What could be the cause of the condition highlighted by the arrow in the occlusal radiograph of an 8-year-old child?

Mesiodens. ***Mesiodens*** - **Mesiodens** is the most common **supernumerary tooth** found in the **maxillary midline**, typically visible on occlusal radiographs in children. - It appears as an **extra tooth structure** between the central incisors and can cause **delayed eruption** or **displacement** of permanent teeth. *Non-vital tooth* - A **non-vital tooth** would show signs of **pulpal necrosis** or **periapical pathology** but would not appear as an additional tooth structure. - This condition involves **existing teeth** losing vitality, not the presence of **supernumerary teeth**. *Impacted tooth* - An **impacted tooth** is part of the **normal dentition** that fails to erupt properly due to **lack of space** or **obstruction**. - It would not appear as an **extra tooth** but rather as a **displaced normal tooth** in an abnormal position. *Ghost tooth* - **Ghost tooth** refers to **regional odontodysplasia**, characterized by **hypocalcified** and **hypoplastic** tooth structure with a **ghostly appearance**. - This condition affects **existing teeth** making them appear **radiolucent** and malformed, not creating **additional tooth structures**.

Q: The lung-head ratio is useful in the diagnosis of which of the following conditions?

Congenital diaphragmatic hernia. **Explanation:** The **Lung-to-Head Ratio (LHR)** is a critical prenatal ultrasonographic parameter used primarily to assess the severity of pulmonary hypoplasia in fetuses with **Congenital Diaphragmatic Hernia (CDH)**. In CDH, abdominal viscera herniate into the thoracic cavity, compressing the developing lungs. The LHR is calculated by measuring the area of the contralateral (healthy) lung at the level of the four-chamber view of the heart and dividing it by the fetal head circumference. A lower LHR indicates more severe pulmonary hypoplasia and correlates with a poorer prognosis and higher need for postnatal ECMO (Extracorporeal Membrane Oxygenation). **Analysis of Incorrect Options:** * **Sequestration:** While this is a bronchopulmonary malformation, it is characterized by non-functional lung tissue with an anomalous systemic blood supply. Diagnosis is usually based on identifying the feeding systemic artery via Doppler, not LHR. * **Ileal Atresia:** This is a distal bowel obstruction. Antenatal ultrasound typically shows dilated bowel loops and polyhydramnios, but it does not involve lung measurement. * **Esophageal Atresia:** This is suggested prenatally by a "small or absent stomach bubble" and polyhydramnios. It does not directly impact lung volume in a way that requires LHR measurement. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type of CDH:** Bochdalek hernia (Posterolateral, more common on the **Left** side). * **Morgagni Hernia:** Anterior/Retrosternal, usually occurs on the right side. * **Observed/Expected LHR (o/e LHR):** A more modern refinement of LHR that accounts for gestational age to better predict survival. * **Scaphoid abdomen:** A classic physical exam finding in newborns with CDH.

Q: Given the provided X-ray of a neonate, what is the diagnosis?

Congenital diaphragmatic hernia. ***Congenital diaphragmatic hernia*** - Classic neonatal chest X-ray shows **bowel loops in the thoracic cavity** with **mediastinal shift** away from the affected side, typically left-sided. - Associated with **pulmonary hypoplasia** and immediate respiratory distress in newborns due to lung compression. *Malrotation* - Primarily an **abdominal condition** affecting bowel positioning around the **superior mesenteric artery**. - Chest X-ray would be normal; diagnosis requires **upper GI series** showing abnormal duodenal positioning. *Pulmonary sequestration* - Shows a **well-defined lung mass** with abnormal **systemic arterial supply** from the aorta. - Does not cause **bowel loops in chest** or immediate severe respiratory distress in neonates. *Pneumatoceles* - Appear as **thin-walled air-filled cysts** within the lung parenchyma, typically following pneumonia. - Do not show **bowel gas patterns** in the chest or cause mediastinal shift.

Question 1

The "triangular cord sign" on ultrasonography is indicative of which condition in a neonate?

Accepted Answer

Biliary atresia

Answer

Galactosemia

Answer

Hepatitis

Answer

None of the above

Question 2

An X-ray of a neonate's abdomen reveals which of the following findings?

Accepted Answer

Pneumatosis intestinalis

Answer

Duodenal atresia

Answer

Jejunal atresia

Answer

Hirschsprung's disease

Question 3

What could be the cause of the condition highlighted by the arrow in the occlusal radiograph of an 8-year-old child?

Accepted Answer

Mesiodens

Answer

Non-vital tooth

Answer

Impacted tooth

Answer

Ghost tooth

Question 4

The lung-head ratio is useful in the diagnosis of which of the following conditions?

Accepted Answer

Congenital diaphragmatic hernia

Answer

Sequestration

Answer

Ileal atresia

Answer

Esophageal atresia

Question 5

Given the provided X-ray of a neonate, what is the diagnosis?

Accepted Answer

Congenital diaphragmatic hernia

Answer

Malrotation

Answer

Pulmonary sequestration

Answer

Pneumatoceles

Pediatric Radiology — MCQs

Pediatric Radiology — MCQs

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