Radiology flashcards for NEET PG
75 cards. Read the question, answer in your head, then check. For spaced repetition, study the deck in the app.
What this deck is for
These 75 cards pick out single facts in Radiology that the exam keeps returning to: CT physics, MRI, Neuroimaging, Cardiac imaging, Radiobiology, Chest imaging and more. Learn signs with the image, and the disease they point to. Cards are a starting set, not full coverage of the subject; the study guide lists the full map.
Where students slip in Radiology: Choosing the most advanced modality instead of the most appropriate. Read the Radiology study guide.
1 · CT physics
Hounsfield units of air, water and dense bone?
Show the answer
Air −1000, water 0, dense bone about +1000.
Memory hook: Water is the zero.
2 · MRI
What appears bright on T1 and on T2?
Show the answer
T1: fat is bright, CSF dark. T2: fluid is bright.
Memory hook: T2 = water.
3 · Neuroimaging
First test in suspected subarachnoid haemorrhage?
Show the answer
Non-contrast CT head; if negative and suspicion remains, lumbar puncture for xanthochromia.
Memory hook: Blood is white on CT.
4 · Cardiac imaging
Chest radiograph shapes: boot, egg on a string, snowman?
Show the answer
Boot: Tetralogy of Fallot. Egg on a string: transposition. Snowman: supracardiac TAPVC.
Memory hook: Shapes cue the diagnosis.
5 · Radiobiology
Most radiosensitive cells, and the rule behind it?
Show the answer
Lymphocytes; law of Bergonié and Tribondeau (dividing, undifferentiated cells are sensitive).
Memory hook: Neurons and muscle are resistant.
6 · Chest imaging
What is the investigation of choice for suspected pulmonary embolism?
Show the answer
CT pulmonary angiography.
Memory hook: V/Q scan if CT is unsuitable.
7 · Chest imaging
What does ground-glass opacity on CT represent?
Show the answer
Partial filling of airspaces or interstitial thickening, seen in viral pneumonia, pneumocystis, and pulmonary oedema.
Memory hook: Vessels remain visible.
8 · Chest imaging
What do Kerley B lines indicate?
Show the answer
Thickened interlobular septa from interstitial pulmonary oedema.
Memory hook: Short horizontal lines at the bases.
9 · Urological imaging
What is the best test for suspected ureteric colic?
Show the answer
Non-contrast CT of kidneys, ureters and bladder.
Memory hook: Ultrasound in pregnancy.
10 · Radiation protection
What does ALARA mean?
Show the answer
As low as reasonably achievable: keep radiation dose as low as possible while obtaining the needed information.
Memory hook: Time, distance and shielding.
11 · Imaging modalities and physics
Which imaging modality uses no ionising radiation and is preferred for pelvic and obstetric imaging first-line?
Show the answer
Ultrasound.
Memory hook: Sound, not rays.
12 · Imaging modalities and physics
Which ultrasound mode is used to assess blood flow direction and velocity?
Show the answer
Doppler ultrasound.
Memory hook: Doppler = flow.
13 · Imaging modalities and physics
Which ultrasound transducer frequency is used for superficial structures such as thyroid and breast?
Show the answer
High frequency (7-15 MHz); it gives better resolution but less penetration.
Memory hook: High frequency, shallow depth.
14 · Imaging modalities and physics
What is the basis of MRI signal?
Show the answer
Hydrogen protons in a strong magnetic field are excited by radiofrequency pulses and emit signal as they relax.
Memory hook: Protons, not X-rays.
15 · Imaging modalities and physics
Which MRI sequence best shows acute infarct within minutes of onset?
Show the answer
Diffusion-weighted imaging (DWI) with low ADC.
Memory hook: Restricted diffusion.
16 · Imaging modalities and physics
Which contrast agent is used in MRI?
Show the answer
Gadolinium-based contrast.
Memory hook: Gado for MRI, iodine for CT.
17 · Imaging modalities and physics
Which complication follows gadolinium in severe renal failure?
Show the answer
Nephrogenic systemic fibrosis.
Memory hook: Skin thickening with renal failure.
18 · Imaging modalities and physics
Which investigation is best for detecting small calcifications and bone cortex detail?
Show the answer
CT, which shows calcium and cortical bone better than MRI.
Memory hook: CT for calcium and bone.
19 · Radiation safety and radiobiology
What is the SI unit of absorbed dose?
Show the answer
Gray (Gy); 1 Gy = 1 joule per kg.
Memory hook: Gray absorbs.
20 · Radiation safety and radiobiology
What is the SI unit of effective (equivalent) dose?
Show the answer
Sievert (Sv).
Memory hook: Sievert = biological effect.
21 · Radiation safety and radiobiology
What is the SI unit of radioactivity?
Show the answer
Becquerel (Bq), one disintegration per second.
Memory hook: Becquerel = decays.
22 · Radiation safety and radiobiology
What is the radiation weighting factor for X-rays and gamma rays?
Show the answer
1.
Memory hook: Photons are the reference.
23 · Radiation safety and radiobiology
Which radiation has the highest radiation weighting factor?
Show the answer
Alpha particles (20).
Memory hook: Heavy and densely ionising.
24 · Radiation safety and radiobiology
Which type of radiation effect has no threshold dose?
Show the answer
Stochastic effects such as cancer and hereditary effects.
Memory hook: Chance, no threshold.
25 · Radiation safety and radiobiology
What type of effect is cataract or skin erythema after radiation?
Show the answer
Deterministic (tissue reaction), with a threshold dose; severity rises with dose.
Memory hook: Threshold, then severity.
26 · Radiation safety and radiobiology
Which is the most radiosensitive phase of the cell cycle?
Show the answer
G2-M phase.
Memory hook: Mitosis is vulnerable.
27 · Radiation safety and radiobiology
Which material is used for shielding X-rays in a radiology room?
Show the answer
Lead.
Memory hook: Lead aprons.
28 · Chest and cardiac imaging
Which sign on chest X-ray indicates pneumoperitoneum under erect film?
Show the answer
Free air under the diaphragm.
Memory hook: Gas rises.
29 · Chest and cardiac imaging
What does the silhouette sign mean on chest X-ray?
Show the answer
Loss of a normal border because adjacent structure has the same density, localising the lesion.
Memory hook: Loss of border.
30 · Chest and cardiac imaging
Which sign indicates a pneumothorax on supine film?
Show the answer
Deep sulcus sign.
Memory hook: Deep costophrenic angle.
31 · Chest and cardiac imaging
What does air bronchogram indicate?
Show the answer
Air-filled bronchi seen within consolidated alveoli, so the lesion is alveolar, as in lobar pneumonia.
Memory hook: Airspace disease.
32 · Chest and cardiac imaging
What does a meniscus sign at the costophrenic angle indicate?
Show the answer
Pleural effusion, seen as a curved upward fluid margin at the costophrenic angle.
Memory hook: Fluid curves up.
33 · Chest and cardiac imaging
Which imaging finding is typical of pulmonary arterial hypertension on chest X-ray?
Show the answer
Enlarged central pulmonary arteries with peripheral pruning.
Memory hook: Big centre, thin edge.
34 · Chest and cardiac imaging
Which chest X-ray sign is seen in coarctation of the aorta?
Show the answer
Rib notching of the inferior rib borders and the figure of 3 sign.
Memory hook: Collaterals erode ribs.
35 · Chest and cardiac imaging
Which finding on chest X-ray suggests aortic dissection?
Show the answer
Widened mediastinum; CT angiography is the confirming investigation.
Memory hook: Wide mediastinum.
36 · Chest and cardiac imaging
What is a normal cardiothoracic ratio on an adult PA chest film?
Show the answer
Less than 0.5 (50%).
Memory hook: Half or less.
37 · Abdominal and GI imaging
Which sign on plain X-ray indicates sigmoid volvulus?
Show the answer
Coffee-bean sign (omega loop).
Memory hook: Bean in the abdomen.
38 · Abdominal and GI imaging
Which barium study sign is seen in achalasia cardia?
Show the answer
Bird's beak (rat-tail) narrowing of the lower oesophagus with a dilated proximal oesophagus.
Memory hook: Beak at the bottom.
39 · Abdominal and GI imaging
Which barium finding is seen in carcinoma of the oesophagus?
Show the answer
Irregular shouldered stricture.
Memory hook: Apple core.
40 · Abdominal and GI imaging
Which sign on barium enema is typical of colon carcinoma?
Show the answer
Apple-core lesion.
Memory hook: Napkin ring.
41 · Abdominal and GI imaging
Which sign is seen on barium enema in Hirschsprung disease?
Show the answer
Narrow aganglionic distal segment with a transition zone and proximal dilatation.
Memory hook: Transition zone.
42 · Abdominal and GI imaging
Which radiological sign suggests intussusception on ultrasound?
Show the answer
Target (doughnut) sign.
Memory hook: Target in a child.
43 · Abdominal and GI imaging
Which imaging investigation is first-line for suspected acute cholecystitis?
Show the answer
Ultrasound abdomen (stones, wall thickening, sonographic Murphy sign).
Memory hook: Ultrasound first.
44 · Abdominal and GI imaging
Which sign on plain abdominal film suggests small bowel obstruction?
Show the answer
Dilated small bowel loops with multiple air-fluid levels in a step-ladder pattern.
Memory hook: Step ladder.
45 · Abdominal and GI imaging
Which finding on plain film is called Rigler sign?
Show the answer
Air on both sides of the bowel wall, indicating pneumoperitoneum.
Memory hook: Both sides visible.
46 · Neuroimaging
Which test is first-line in acute head trauma?
Show the answer
Non-contrast CT head.
Memory hook: Fast and sees bone and blood.
47 · Neuroimaging
What is the CT shape of an extradural haematoma?
Show the answer
Biconvex (lentiform), not crossing sutures.
Memory hook: Lens, stops at sutures.
48 · Neuroimaging
What is the CT shape of a subdural haematoma?
Show the answer
Crescentic, crossing sutures but not the midline dural folds.
Memory hook: Crescent.
49 · Neuroimaging
Which is the best investigation for early cerebral infarct within hours?
Show the answer
MRI diffusion-weighted imaging; CT excludes haemorrhage first.
Memory hook: DWI lights up.
50 · Neuroimaging
Which MRI feature suggests multiple sclerosis?
Show the answer
Periventricular white matter plaques, Dawson fingers, perpendicular to the ventricles.
Memory hook: Dawson fingers.
51 · Neuroimaging
Which investigation is best for posterior fossa lesions?
Show the answer
MRI, as CT suffers beam-hardening artefacts from bone.
Memory hook: MRI for the posterior fossa.
52 · Neuroimaging
Which imaging sign is seen in tuberculous meningitis?
Show the answer
Basal meningeal enhancement with hydrocephalus.
Memory hook: Basal exudates.
53 · Neuroimaging
What is the typical imaging finding of neurocysticercosis in the vesicular stage?
Show the answer
Non-enhancing cyst with an eccentric scolex (hole-with-dot sign).
Memory hook: Dot inside a cyst.
54 · Neuroimaging
Which imaging finding is typical of herpes simplex encephalitis?
Show the answer
Temporal lobe and insular involvement, often bilateral and asymmetric.
Memory hook: Temporal lobes.
55 · Neuroimaging
Which finding on MRI suggests Chiari I malformation?
Show the answer
Cerebellar tonsils descending more than 5 mm below the foramen magnum.
Memory hook: Tonsils below the foramen.
56 · Musculoskeletal imaging
Which radiological sign is typical of Ewing sarcoma?
Show the answer
Onion-peel periosteal reaction in the diaphysis.
Memory hook: Onion layers.
57 · Musculoskeletal imaging
Which radiological sign is typical of osteosarcoma?
Show the answer
Sunburst periosteal reaction with Codman triangle in the metaphysis.
Memory hook: Sunburst.
58 · Musculoskeletal imaging
Which tumour shows soap-bubble appearance on X-ray?
Show the answer
Giant cell tumour, an eccentric epiphyseal lytic lesion.
Memory hook: Soap bubble at the epiphysis.
59 · Musculoskeletal imaging
Which radiological finding is typical of osteoid osteoma?
Show the answer
Small radiolucent nidus with surrounding sclerosis; pain relieved by NSAIDs.
Memory hook: Nidus.
60 · Musculoskeletal imaging
Which sign on X-ray is seen in Paget disease of bone?
Show the answer
Cotton-wool skull and thickened coarse trabeculae.
Memory hook: Cotton wool.
61 · Musculoskeletal imaging
Which finding on X-ray suggests rickets?
Show the answer
Cupping, fraying and widening of the metaphyses with a widened growth plate.
Memory hook: Cupped metaphysis.
62 · Musculoskeletal imaging
Which finding on spine imaging suggests ankylosing spondylitis?
Show the answer
Bamboo spine with sacroiliitis.
Memory hook: Bamboo.
63 · Musculoskeletal imaging
Which radiological findings are seen in osteoarthritis?
Show the answer
Joint space narrowing, osteophytes, subchondral sclerosis and cysts.
Memory hook: LOSS: loss of space, osteophytes, sclerosis, subchondral cysts.
64 · Musculoskeletal imaging
Which radiological finding is typical of rheumatoid arthritis?
Show the answer
Periarticular osteopenia with marginal erosions and symmetric joint space loss.
Memory hook: Marginal erosions.
65 · Musculoskeletal imaging
Which imaging is the best for detecting early osteomyelitis?
Show the answer
MRI; plain films are normal for the first 10-14 days.
Memory hook: MRI is early.
66 · Radiotherapy and nuclear medicine basics
Which radioisotope is most commonly used in diagnostic nuclear imaging?
Show the answer
Technetium-99m, a pure gamma emitter with a 6-hour half-life.
Memory hook: Tc-99m.
67 · Radiotherapy and nuclear medicine basics
Which scan is used for staging many cancers using fluorine-18 labelled glucose analogue?
Show the answer
FDG-PET.
Memory hook: Sugar-hungry tumours.
68 · Radiotherapy and nuclear medicine basics
Which radioisotope is used for thyroid cancer ablation?
Show the answer
Iodine-131.
Memory hook: I-131 destroys.
69 · Radiotherapy and nuclear medicine basics
Which scan is best for detecting bone metastases?
Show the answer
Tc-99m MDP bone scan.
Memory hook: Hot spots.
70 · Radiotherapy and nuclear medicine basics
Which isotope is used in the treatment of bone metastasis pain?
Show the answer
Strontium-89 or samarium-153.
Memory hook: Bone seekers.
71 · Radiotherapy and nuclear medicine basics
Which radiotherapy source is used in teletherapy units in India?
Show the answer
Cobalt-60 (gamma rays, half-life about 5.26 years) and linear accelerators.
Memory hook: Cobalt unit.
72 · Radiotherapy and nuclear medicine basics
What is brachytherapy?
Show the answer
Radiotherapy delivered with a sealed source placed within or next to the tumour.
Memory hook: Brachy = short distance.
73 · Radiotherapy and nuclear medicine basics
Which tumour is highly radiosensitive and treated mainly by radiotherapy and chemotherapy?
Show the answer
Seminoma.
Memory hook: Sensitive germ cell tumour.
74 · Radiotherapy and nuclear medicine basics
Which scan is used to evaluate suspected pulmonary embolism when CT is contraindicated?
Show the answer
Ventilation-perfusion (V/Q) scan.
Memory hook: Mismatch.
75 · Radiotherapy and nuclear medicine basics
Which scan assesses myocardial perfusion in nuclear cardiology?
Show the answer
Thallium-201 or Tc-99m sestamibi SPECT.
Memory hook: Stress and rest.
Common questions
How many Radiology flashcards are there?
75 cards across 14 topics. The deck grows as we add material.
Which topics are in the Radiology deck?
CT physics, MRI, Neuroimaging, Cardiac imaging, Radiobiology, Chest imaging, Urological imaging, Radiation protection, Imaging modalities and physics, Radiation safety and radiobiology, Chest and cardiac imaging, Abdominal and GI imaging, and more.
Is the Radiology deck free?
Radiology opens with a paid term. The free plan includes the Anatomy, Physiology and Biochemistry decks.
How do spaced-repetition cards work?
You rate each card Again, Hard, Good or Easy. Cards you find hard return soon and cards you know return later, so your time goes where you forget.
What is the memory hook on a card?
75 of these cards carry a one-line hook: a short cue that helps the answer stick. It is optional and appears after you reveal the answer.
How many Radiology cards should I do a day?
Ten to twenty minutes a day is plenty. A few due cards every day beat a long session once a week.
Can I flip through the cards on this page?
You can read each question and reveal its answer here. For scheduling, ratings and progress, study the deck in the app.
Are the Radiology cards reviewed by faculty?
Not yet. They are original and still awaiting independent review, so confirm anything important in a standard textbook.