PLAB 2: Mastering Essential Radiology Guidelines for OSCE Success

PLAB 2: Mastering Essential Radiology Guidelines for OSCE Success

As an International Medical Graduate (IMG) preparing for the PLAB 2 exam, you're acutely aware that practical skills are paramount. While clinical stations often focus on history taking, examination, and communication, the ability to interpret basic radiological investigations is a frequently tested and crucial skill. Mastering essential radiology guidelines is not just about identifying pathologies; it's about applying a systematic approach and understanding when and how to interpret images in a real-world clinical context, as expected by the GMC.

Why Radiology Guidelines are Crucial for PLAB 2

PLAB 2 assesses your competence as a foundation year (FY2) doctor. At this level, you're expected to recognize common life-threatening conditions, identify key findings on basic imaging, and know when to escalate or refer. The exam often presents scenarios where you might be shown an X-ray or asked to discuss imaging findings. Your ability to interpret these effectively, following established guidelines, can significantly impact your score.

Systematic Approach to Common Radiological Investigations

For PLAB 2, focus on Chest X-rays (CXR), Abdominal X-rays (AXR), and basic limb X-rays. Here's a guideline-based approach:

1. Chest X-rays (CXR)

Adopt a systematic ABCDE approach:

• A - Airway: Check the trachea for deviation. Is it central? If deviated, what could be causing it (e.g., tension pneumothorax, large pleural effusion)?

• B - Bones: Look for fractures (ribs, clavicles, humerus), lytic or sclerotic lesions. Assess bone density.

• C - Cardiac Silhouette: Evaluate heart size (cardiothoracic ratio < 0.5 in AP view), borders, and the presence of any valvular prostheses or pacing wires.

• D - Diaphragm: Are the hemidiaphragms well-defined? Is there air under the diaphragm (perforation)? Check costophrenic angles for blunting (effusion).

• E - Effusion/Fields: Assess lung fields symmetrically for opacities, consolidation, infiltrates, hyperinflation, vascular markings, and interstitial patterns. Look for pneumothorax (absence of lung markings, visceral pleural line) or pleural effusions.

Common Pathologies and Key Findings:

• Pneumonia: Lobar or segmental consolidation, air bronchograms.

• Pulmonary Oedema: Bilateral perihilar shadowing (batwing appearance), upper lobe diversion, Kerley B lines, pleural effusions.

• Pneumothorax: Absent lung markings peripheral to the visceral pleural line. If tension, mediastinal shift.

• Pleural Effusion: Blunting of costophrenic angles, meniscus sign.

• COPD: Hyperinflation, flattened diaphragms, increased retrosternal space.

2. Abdominal X-rays (AXR)

AXRs are primarily useful for bowel obstruction, perforation, and identifying foreign bodies. A systematic approach involves looking at:

• Bowel Gas Pattern: Normal gas distribution, dilated loops, fluid levels.

• Solid Organs: Liver, spleen, kidneys outlines.

• Psoas Shadows: Should be visible bilaterally.

• Bones: Vertebrae, pelvic bones for fractures or lesions.

• Calcifications: Renal calculi, gallstones, vascular calcifications.

Common Pathologies and Key Findings:

• Small Bowel Obstruction: Dilated small bowel loops (>3cm diameter) with valvulae conniventes, multiple air-fluid levels (ladder pattern).

• Large Bowel Obstruction: Dilated large bowel loops (>6cm, caecum >9cm) with haustra, absence of distal gas.

• Perforation: Free air under the diaphragm (best seen on erect CXR), or outlining the falciform ligament on supine AXR.

• Constipation/Faecal Impaction: Loaded colon with faeces.

3. Limb X-rays

When interpreting limb X-rays, consider two orthogonal views (AP and lateral) and use the '2 of everything' rule (2 views, 2 joints, 2 sides if comparing).

• General Assessment: Bone alignment, fractures (location, type, displacement, angulation), soft tissue swelling, foreign bodies, joint spaces.

• Salter-Harris Classification: For paediatric epiphyseal plate injuries.

When to Order Further Imaging

PLAB 2 also tests your clinical judgment. Know when a basic X-ray is insufficient and further imaging (e.g., CT, MRI, ultrasound) is warranted. For instance:

• Suspected stroke or head injury: Urgent CT head.

• Acute abdomen with equivocal AXR: CT abdomen and pelvis.

• Deep Vein Thrombosis (DVT): Ultrasound Doppler.

Communication & Clinical Correlation

Remember to integrate your radiological findings with the patient's clinical presentation. In the OSCE, you'll be expected to:

• Describe findings clearly: Use appropriate terminology.

• Correlate with history/examination: Explain how the imaging supports or refutes your differential diagnoses.

• Formulate a management plan: Based on the findings, including appropriate referral or escalation to senior colleagues.

• Communicate findings to the patient (if applicable): Use clear, empathetic language.

Practice Makes Perfect

The best way to master radiology for PLAB 2 is through consistent practice. Review common X-ray images, follow a systematic approach every time, and understand the clinical context. Resources like Radiology Assistant, Radiopaedia, and question banks with image-based questions are invaluable. By integrating essential radiology guidelines into your study, you'll not only ace the exam but also lay a strong foundation for safe and effective clinical practice in the UK.

Good luck with your preparation – your ability to interpret these images confidently will truly set you apart!