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RD7.5 | Imaging in Paediatrics — Practice Quiz
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A 3-year-old child presents with 2 days of fever, cough and tachypnoea. On examination she is alert, feeding normally, well-perfused and has an SpO2 of 97% on room air; auscultation reveals crepitations in the right lower zone consistent with uncomplicated community-acquired pneumonia. What is the most appropriate imaging decision?
Correct. For a well child with uncomplicated clinical community-acquired pneumonia, WHO and most guidelines advise treating clinically without routine imaging — a radiograph adds ionising radiation without changing management. Imaging is reserved for deterioration, diagnostic doubt or suspected complications.
Uncomplicated clinical pneumonia in a well child needs NO routine chest radiograph. Withholding the film is itself a clinical skill that honours ALARA / 'image gently'.
In an uncomplicated, well, non-hypoxic child the diagnosis of pneumonia is clinical. Routine radiographs (and certainly CT or repeated films) only add radiation without altering management; imaging is reserved for complications or clinical doubt.
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A 4-year-old with pneumonia fails to improve after 48 hours of appropriate antibiotics and now has reduced breath sounds and dullness at the right base, raising suspicion of a parapneumonic effusion/empyema. Which imaging modality is the most appropriate next step to assess the pleural fluid?
Correct. Ultrasound is the preferred modality to detect and characterise a parapneumonic effusion/empyema — it identifies fluid, distinguishes simple from septated/loculated collections, estimates volume and can guide drainage, all without ionising radiation.
USG is the modality of choice for paediatric pleural effusion/empyema — no radiation, characterises septations, and guides drainage. CT only for complications USG cannot resolve.
For pleural fluid in a child, ultrasound is the test of choice: it confirms and characterises the effusion (simple vs loculated) and guides drainage without radiation. CT is reserved for complications not resolved by USG; MRI/PET-CT have no first-line role here.
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A 16-month-old toddler had a sudden choking episode while eating peanuts, followed by intermittent cough and wheeze. A frontal chest radiograph taken at presentation appears normal. Which statement best guides further management?
Correct. Most paediatric aspirated objects are organic and radiolucent and cast no shadow, so a normal film is common and does NOT exclude a foreign body. With a convincing choking history, rigid bronchoscopy — both diagnostic and therapeutic — is indicated.
A normal X-ray never clears a choking history — most aspirated objects are radiolucent. Bronchoscopy is diagnostic AND therapeutic; clinical suspicion, not the film, drives the decision.
The cardinal rule is that a NORMAL chest radiograph never clears a choking history. Most inhaled objects are organic and radiolucent. A convincing history mandates bronchoscopy, which is both diagnostic and therapeutic.
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A 2-year-old with a witnessed aspiration episode has a chest radiograph showing unilateral hyperinflation (air-trapping) of the right lung, with the mediastinum shifted to the LEFT. An expiratory film accentuates the asymmetry. Which mechanism best explains these findings?
Correct. A ball-valve foreign body lets air in but not out, causing distal air-trapping/hyperinflation that worsens on expiration and shifts the mediastinum AWAY from the affected side. Complete obstruction would instead cause collapse with the mediastinum pulled TOWARDS the side.
Indirect signs of FB aspiration: air-trapping/hyperinflation (worse on expiratory or decubitus films) shifts mediastinum AWAY; collapse/atelectasis shifts it TOWARDS the lesion.
Air-trapping from a partially obstructing (ball-valve) foreign body causes hyperinflation that worsens on expiration and shifts the mediastinum AWAY from the affected side. Collapse from complete obstruction pulls the mediastinum TOWARDS the side — the opposite shift.
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A 6-month-old infant has a first confirmed febrile (upper-tract) urinary tract infection. According to age- and risk-based protocols (NICE/ISPN), which imaging investigation is the most appropriate FIRST-line study?
Correct. Ultrasound (KUB) is the first-line, non-ionising study in paediatric UTI — it answers 'is the anatomy normal?' (hydronephrosis, duplex, dilatation, bladder abnormality). MCUG (for reflux) and DMSA (for scarring) are added selectively by age, atypia or recurrence.
One tool, one question: USG = 'is the anatomy normal?' (first-line), MCUG = 'is there reflux and how bad?', DMSA = 'is the cortex scarred?'. Lead with the non-ionising test (ALARA).
USG (KUB) is the non-ionising first-line study and answers the anatomical question. MCUG is reserved for assessing reflux and DMSA for cortical scarring, used selectively by age/risk. CT and IVU are not first-line in paediatric UTI.
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A 1-year-old with recurrent febrile UTIs has an ultrasound showing bilateral hydronephrosis. A micturating cystourethrogram is performed to investigate vesicoureteric reflux. What does the MCUG specifically grade, and over what range?
Correct. The MCUG/VCUG demonstrates and grades vesicoureteric reflux from I to V (I = into a non-dilated ureter; V = gross dilatation with tortuosity and loss of papillary impressions). Cortical scarring and differential function are assessed by DMSA, not MCUG.
MCUG/VCUG grades VUR I–V. DMSA (not MCUG) shows cortical scarring and split function. Match each tool to the single question it answers.
MCUG grades vesicoureteric reflux on a I–V scale (I = ureter only; V = gross dilatation/tortuosity). Cortical scarring and split renal function are the domain of DMSA scintigraphy, not the MCUG.
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