NEET PG Rapid Revision
Radiology One-Liners for NEET PG: Rapid Revision
High-yield radiology one-liners for NEET PG covering imaging modalities, classic radiological signs, contrast studies and radiation physics.
MedNext Academy | 6 min read
Radiology One-Liners for NEET PG: Rapid Revision
High-yield radiology one-liners for NEET PG covering imaging modalities, classic radiological signs, contrast studies and radiation physics.
Radiology: rapid revision one-liners for NEET PG
Radiology in NEET PG tests your knowledge of imaging modalities, classic radiological signs, contrast studies and basic radiation physics. Questions are often image-based, asking you to identify a finding or choose the appropriate imaging modality for a clinical scenario.
These one-liners cover the most commonly tested radiological signs, imaging modality indications and radiation safety concepts. Radiology overlaps with almost every clinical subject, so these facts reinforce learning across the entire curriculum.
Must-know one-liners
- CT scan is the investigation of choice for acute head trauma and suspected intracranial haemorrhage
- MRI is the investigation of choice for posterior fossa lesions, spinal cord pathology, soft tissue tumours and white matter diseases (MS, encephalitis)
- MRI uses radiofrequency waves in a magnetic field; no ionising radiation; T1-weighted images show anatomy (fat is bright), T2-weighted images show pathology (fluid is bright)
- Gadolinium is the MRI contrast agent; contraindicated in severe renal failure (risk of nephrogenic systemic fibrosis)
- CT contrast agents are iodine-based; risk of contrast-induced nephropathy (hydration is preventive) and anaphylactoid reactions
- Ultrasound is the first-line imaging for pregnancy, paediatric abdomen, thyroid, breast (in young women) and musculoskeletal soft tissues; no radiation
- Doppler ultrasound is used for assessing blood flow velocity and direction; duplex Doppler is the investigation of choice for DVT
- X-ray: first-line imaging for chest, bones and acute abdomen; posteroanterior (PA) view is standard for chest X-ray
- Air-fluid levels on erect abdominal X-ray indicate intestinal obstruction; free air under the diaphragm indicates perforation (pneumoperitoneum)
- Ground-glass opacity on chest X-ray/CT: Pneumocystis jirovecii pneumonia, pulmonary alveolar proteinosis, ARDS, neonatal respiratory distress syndrome
- Honeycomb pattern on CT chest indicates end-stage interstitial lung disease (usual interstitial pneumonia/IPF)
- Silicosis: bilateral upper zone fibrosis with eggshell calcification of hilar lymph nodes on chest X-ray
- Miliary pattern on chest X-ray: miliary tuberculosis, miliary metastases (thyroid, renal, melanoma), sarcoidosis, histoplasmosis
- Bat-wing/butterfly pattern of perihilar opacification on chest X-ray: pulmonary oedema
- Kerley B lines on chest X-ray: short horizontal lines at the lung bases indicating interstitial oedema or lymphangitis carcinomatosa
- Hampton hump (wedge-shaped opacity) and Westermark sign (oligaemia) on chest X-ray suggest pulmonary embolism; CTPA is the definitive investigation
- Boot-shaped heart on chest X-ray: tetralogy of Fallot (coeur en sabot); egg-on-string: transposition of great arteries
- Figure-of-eight/snowman sign on chest X-ray: total anomalous pulmonary venous connection (TAPVC) supracardiac type
- Rib notching on chest X-ray: coarctation of the aorta (inferior surface of ribs 3-8, caused by collateral intercostal arteries)
- Double-bubble sign on abdominal X-ray in a neonate: duodenal atresia (associated with Down syndrome)
- Apple-core/napkin-ring lesion on barium enema: annular carcinoma of the colon
- Bird-beak sign on barium swallow: achalasia cardia; rat-tail narrowing: carcinoma lower oesophagus
- Corkscrew/rosary-bead oesophagus on barium swallow: diffuse oesophageal spasm
- String sign of Kantor on barium meal follow-through: Crohn disease (terminal ileum narrowing)
- Lead-pipe colon on barium enema: ulcerative colitis (loss of haustrations)
- Thumb-printing on barium enema or CT: mucosal oedema in ischaemic colitis, inflammatory bowel disease
- Codman triangle on bone X-ray: periosteal elevation by tumour; seen in osteosarcoma
- Sunburst/sunray pattern: osteosarcoma; onion-skin/onion-peel periosteal reaction: Ewing sarcoma
- Soap-bubble appearance on bone X-ray: giant cell tumour (GCT) of bone
- Punched-out lytic lesions in the skull: multiple myeloma; also seen in metastases and eosinophilic granuloma
- Rugger jersey spine: hyperparathyroidism (alternating sclerotic and lucent bands in vertebral bodies); pepper-pot skull: primary hyperparathyroidism
- Bamboo spine: ankylosing spondylitis (syndesmophytes bridging adjacent vertebrae); sacroiliitis is the earliest radiological finding
- Widened mediastinum on chest X-ray: aortic dissection/rupture, lymphoma, thymoma; CT angiography is the investigation of choice for aortic dissection
- Target sign on ultrasound: intussusception (concentric rings of bowel); pneumatic/hydrostatic reduction under fluoroscopy or US
- Staghorn calculus on KUB X-ray: struvite stone (magnesium ammonium phosphate); associated with Proteus urease-producing infection
- Horseshoe kidney: fused lower poles; most common renal fusion anomaly; trapped under the inferior mesenteric artery
- IVU (intravenous urography) is used for evaluating the urinary tract; flower-vase/drooping-lily sign: duplex kidney with upper pole obstruction
- Nutcracker phenomenon: compression of the left renal vein between the aorta and SMA; causes haematuria
- Nuclear medicine: technetium-99m is the most commonly used radionuclide; half-life 6 hours
- PET scan uses 18F-FDG (fluorodeoxyglucose); detects metabolically active tissues; most useful for staging malignancies and detecting recurrence
- DEXA scan: gold standard for measuring bone mineral density; T-score <= -2.5 = osteoporosis; -1 to -2.5 = osteopenia
- HSG (hysterosalpingography): used to evaluate tubal patency in infertility workup; uses iodine-based contrast through the cervix under fluoroscopy
- Mammography: screening investigation for breast cancer; BIRADS classification (0-6) standardises reporting
- Radiation units: Gray (Gy) = absorbed dose; Sievert (Sv) = equivalent dose (accounts for biological effectiveness); Becquerel (Bq) = activity
- Maximum permissible radiation dose for occupational workers: 20 mSv per year averaged over 5 years (ICRP recommendation)
- ALARA principle: As Low As Reasonably Achievable -- the guiding principle of radiation protection
- Inverse square law: radiation intensity is inversely proportional to the square of the distance from the source; doubling the distance reduces exposure to one-quarter
- Lead aprons (0.5 mm lead equivalent) attenuate approximately 95% of scattered radiation in the diagnostic energy range
- Mammography uses molybdenum or rhodium target to produce low-energy X-rays for better soft tissue contrast
- Hounsfield units on CT: water = 0, air = -1000, bone = +1000, fat = -50 to -100, acute blood = +50 to +70
How to use these one-liners
Radiology one-liners are best revised alongside images. For each radiological sign, try to recall or look up the corresponding image. This visual association is what makes the fact stick.
Group the signs by imaging modality (X-ray signs, barium study signs, CT signs, MRI indications) and by system (chest, abdomen, bone, neuro). Pay special attention to the investigation of choice for common clinical scenarios -- this is the most commonly tested question format.
Key mnemonics
T1 = anatomy (fat is bright); T2 = pathology (fluid/water is bright). Think: T-ONE = anatomy, T-TWO = water (both have 'w' in a sense -- T2 shows Water).
Boot-shaped heart = TOF (Tetralogy Of Fallot); Egg-on-string = TGA (Transposition of Great Arteries).
Codman triangle = periosteal elevation = osteosarcoma; Onion-skin = Ewing; Soap-bubble = GCT.
Revision schedule
Radiology one-liners should be revised every 4-5 days. Cover imaging signs and modality indications in one session, and radiation physics/safety in another. In the final week, one complete run-through every 2 days is sufficient. This subject has a very high marks-to-effort ratio because the same classic signs are tested repeatedly.
Frequently Asked Questions
How many radiology questions appear in NEET PG?
Typically 5-10 questions. Classic radiological signs, investigation of choice for clinical scenarios, contrast study findings and basic radiation physics are the most commonly tested areas.
Are image-based questions common?
Yes, radiology is one of the most image-heavy subjects. Be able to identify pneumoperitoneum, pneumothorax, intestinal obstruction, bone tumour patterns and common CT/MRI findings from images.
How much radiation physics do I need to know?
Know the basic concepts: radiation units (Gray, Sievert, Becquerel), ALARA principle, inverse square law, permissible dose limits and the properties of commonly used radionuclides (Tc-99m, I-131). Detailed physics is rarely tested.
Should I learn Hounsfield units?
Know the key values: water = 0, air = -1000, bone = +1000, fat = negative values, acute blood = +50-70. This helps in interpreting CT findings and is occasionally asked directly.
Inside MedNext for this topic
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