Sonographic Pattern & Differential Diagnosis Guide
Start with what you see on the screen. For each common clinical scenario this guide lays out the pattern-based differential — the appearances that point one way or another — and gives you the single sonographic discriminator (and, where they exist, the validated scoring systems: ACR TI-RADS, O-RADS US v2022, BI-RADS, IOTA) that separates one diagnosis from the next. Pick a scenario on the left.
A teaching aid, not a report. This guide summarises pattern recognition and published risk-stratification systems for revision and bedside orientation. It is not a substitute for a formal ultrasound examination, structured report or specialist opinion, and does not by itself justify a management decision. Scoring systems (TI-RADS, O-RADS, BI-RADS, IOTA) must be applied to complete, correctly acquired images with the full clinical context; category thresholds, size cut-offs and follow-up rules are periodically revised — always confirm against the current ACR/AIUM/RCR guidance and your department’s protocol. Ultrasound is profoundly operator-dependent; nothing here replaces supervised training and radiologist correlation.
Focal liver lesion
First questions: is it cystic (anechoic, through-transmission) or solid? Single or multiple? Is the background liver normal, fatty or cirrhotic (cirrhosis changes the pre-test probability toward HCC)? Grey-scale morphology is suggestive but rarely diagnostic — a target/”bull’s-eye” sign or a peripheral hypoechoic halo raises concern for metastasis or HCC, while a uniformly hyperechoic well-defined lesion in a normal liver is most often a haemangioma. Contrast-enhanced ultrasound (CEUS) enhancement phase is the single most useful non-invasive discriminator; equivocal lesions go to multiphase CT/MRI.
Simple hepatic cyst Benign
Anechoic, thin/imperceptible wall, round or ovoid, no internal echoes.
Marked posterior acoustic enhancement (through-transmission); often thin edge shadows.
No internal flow. CEUS: no enhancement in any phase.
May be multiple (simple cysts, polycystic liver disease). Very common incidental finding.
- Anechoic + through-transmission + no wall/flow = simple cyst; nothing further needed.
- Internal echoes, septa, mural nodularity, thick wall or a solid component take it out of “simple” → complicated cyst, abscess, cystic neoplasm (biliary cystadenoma/carcinoma), or hydatid → characterise / cross-sectional imaging.
Haemangioma Benign
Classically small, well-defined, uniformly hyperechoic, often subcapsular. Larger ones can be heterogeneous with hypoechoic areas.
May show subtle posterior enhancement; no halo.
Little/no colour flow (slow flow). CEUS: peripheral nodular/globular discontinuous enhancement with progressive centripetal fill-in.
Most common benign hepatic tumour; stable over time.
- Uniformly hyperechoic, well-defined lesion in an otherwise normal liver → most likely haemangioma. But a hyperechoic lesion in a fatty liver loses this specificity, and metastases (esp. colorectal, neuroendocrine) can be hyperechoic.
- CEUS peripheral globular fill-in is characteristic and avoids biopsy; atypical/large lesions → MRI (T2 “light-bulb”, progressive fill-in).
Focal nodular hyperplasia (FNH) Benign
Often near-isoechoic (“stealth lesion”) — detected mainly by mass effect on vessels. May show a central scar.
None specific.
Central feeding artery with spoke-wheel vascularity. CEUS: bright arterial-phase enhancement from the centre outward, sustained/iso in portal & late phases (no washout).
Young/middle-aged women; benign, no malignant potential.
- Central spoke-wheel artery + no washout on late-phase CEUS favours FNH over adenoma and HCC.
- A central scar is suggestive but not specific (also fibrolamellar HCC, some haemangiomas) — MRI with hepatobiliary contrast confirms.
Hepatocellular adenoma Indeterminate
Variable — often heterogeneous; internal haemorrhage or fat gives mixed echogenicity.
None specific.
Peripheral/subcapsular vessels. CEUS: arterial hyper-enhancement, usually no or late mild washout (helps separate from HCC, which washes out early).
Oral-contraceptive / anabolic-steroid use, glycogen storage disease. Risk of haemorrhage and (β-catenin subtype) malignant transformation.
- Cannot be reliably distinguished from FNH/HCC on ultrasound alone — the clinical context (OCP use) plus MRI subtyping is decisive.
- Early/marked washout should raise concern for HCC rather than adenoma.
Hepatocellular carcinoma (HCC) Malignant
Variable; small HCC often hypoechoic, larger lesions heterogeneous (“mosaic”). A thin peripheral halo (capsule) may be seen.
None specific.
Internal arterial flow (basket pattern). CEUS: arterial-phase hyper-enhancement then washout (typically mild/late washout — distinct from the early marked washout of most metastases).
Background cirrhosis/chronic hepatitis; look for portal-vein tumour thrombus (expansile, arterialised flow within the thrombus).
- New/enlarging solid nodule in a cirrhotic liver is HCC until proven otherwise — go to CEUS LI-RADS or multiphase CT/MRI, don’t just watch.
- Arterial enhancement + washout in a cirrhotic liver is the hallmark; tumour thrombus in the portal vein is essentially diagnostic of malignancy.
Red flag: arterialised, expansile portal-vein thrombus, or a rising AFP with a new nodule — escalate urgently.
Metastases Malignant
Usually multiple; variable echogenicity. The “target”/”bull’s-eye” sign (hypoechoic rim around an echogenic centre) is characteristic.
None specific; may be calcified (mucinous GI primaries).
Variable flow. CEUS: rim/heterogeneous arterial enhancement with early, marked washout (dark lesions in the portal/late phase — the most useful sign of a malignant deposit).
Known/suspected primary; multiplicity; often normal background liver.
- Multiple lesions with a halo/target and early washout on CEUS = metastatic disease; a single hyperechoic lesion is more often benign (haemangioma) but a solitary echogenic met is possible.
- The halo/target sign in a patient with a known malignancy is high-concern — stage with CT/MRI.
Pyogenic / amoebic abscess Don’t-miss
Complex, often hypoechoic/heterogeneous collection with irregular walls; internal debris, septa and sometimes gas (dirty shadowing, ring-down).
Variable posterior enhancement (fluid content).
No flow within the cavity; hyperaemic rim. CEUS: rim enhancement with a non-enhancing necrotic centre.
Fever, rigors, raised inflammatory markers; recent GI infection/travel (amoebic).
- The clinical picture (sepsis) plus a complex cavity with a hyperaemic rim and no central flow is the giveaway; overlaps with necrotic tumour — correlate with bloods, and aspirate/drain as indicated.
- Gas within a hepatic collection strongly suggests abscess.
Adnexal mass
Characterise on transvaginal (± transabdominal) ultrasound: unilocular vs multilocular vs solid, wall/septal thickness, presence and size of solid components/papillary projections, acoustic shadowing, ascites and colour-Doppler flow within solid areas. Two complementary frameworks are widely used: the IOTA Simple Rules (a quick benign-vs-malignant triage) and ACR O-RADS US v2022 (a full 0–5 risk-stratification lexicon). Classic benign lesions (functional cyst, haemorrhagic cyst, endometrioma, dermoid) have specific appearances that place them in low O-RADS categories.
| B-features (benign) | M-features (malignant) |
|---|---|
| B1 — Unilocular cyst | M1 — Irregular solid tumour |
| B2 — Solid components <7 mm (largest) | M2 — Ascites |
| B3 — Acoustic shadows | M3 — At least 4 papillary structures |
| B4 — Smooth multilocular tumour <10 cm | M4 — Irregular multilocular-solid tumour ≥10 cm |
| B5 — No blood flow (colour score 1) | M5 — Very strong blood flow (colour score 4) |
Apply: only M-features → malignant; only B-features → benign; both or neither present → inconclusive (~20% of masses) → assess by an expert or with ADNEX/O-RADS. Conclusive results give ~92% sensitivity, ~96% specificity.
| Category | Meaning | Est. risk of malignancy |
|---|---|---|
| O-RADS 0 | Incomplete evaluation | — |
| O-RADS 1 | Normal (physiological — e.g. follicle ≤3 cm, corpus luteum ≤3 cm) | n/a |
| O-RADS 2 | Almost certainly benign | <1% |
| O-RADS 3 | Low risk | 1% to <10% |
| O-RADS 4 | Intermediate risk | 10% to <50% |
| O-RADS 5 | High risk | ≥50% |
v2022 refinements: added bilocular descriptor for cystic lesions and shadowing for smooth solid lesions, and expanded the classic-benign lexicon (dermoid, endometrioma, haemorrhagic cyst, paraovarian cyst, peritoneal inclusion cyst, hydrosalpinx) to reduce false positives. Higher categories generally prompt specialist/gynae-oncology MDT referral and often MRI or CA-125; management follows the ACR O-RADS management system.
Simple / functional cyst O-RADS 1–2
Unilocular, anechoic, thin smooth wall, no solid component, no flow.
≤3 cm in a premenopausal woman = physiological follicle (O-RADS 1). Simple cyst >3 cm is O-RADS 2.
- Purely anechoic + thin wall + no flow. Any solid/vascular component takes it out of “simple”.
Haemorrhagic cyst O-RADS 2
Fine reticular/lacy (“fishnet/cobweb”) internal strands, or a retracting clot with concave straight margins and no internal flow.
Reticular strands and an avascular clot; the “clot” can mimic a nodule — but it has no Doppler flow and often concave/angular margins.
- Lacy strands + avascular clot with straight/concave edges = haemorrhagic cyst; a true papillary projection has convex margins and may show flow. Reimage 6–12 weeks (early cycle) if uncertain — most resolve.
Endometrioma O-RADS 2
Homogeneous low-level internal echoes (“ground-glass”), often unilocular; may have echogenic wall foci.
Uniform ground-glass echoes with no internal flow; often bilateral; may be multilocular.
- Ground-glass avascular content. Watch for a solid vascular mural nodule → concern for malignant transformation (clear-cell/endometrioid) — that raises the O-RADS category.
Mature cystic teratoma (dermoid) O-RADS 2
Echogenic focus with acoustic shadowing (Rokitansky nodule), “dermoid mesh” (echogenic lines & dots = hair), fat–fluid level.
Acoustic shadowing from fat/calcification + avascular echogenic components.
- Shadowing echogenic Rokitansky nodule / hair lines with no internal flow = dermoid (an IOTA B-feature: acoustic shadows). Correlate: fat–fluid levels are characteristic.
Cystadenoma (serous / mucinous) O-RADS 2–3
Serous: unilocular/thin-septate anechoic. Mucinous: multilocular with low-level echoes of varying density between locules (“stained-glass”).
Smooth thin walls/septa, no solid vascular component; smooth multilocular <10 cm is an IOTA B-feature.
- Thin smooth septa and no vascular solid nodule keep it benign; any irregular thick septa, papillary projections or vascular solid tissue escalate toward borderline/malignant.
Suspicious / malignant mass O-RADS 4–5
Solid or multilocular-solid; irregular thick walls/septa; ≥4 papillary projections; vascular solid components; ascites; peritoneal deposits.
Vascular solid tissue (colour score 3–4), papillary projections, ascites — the IOTA M-features.
- A vascular solid component / papillary projection is the pivotal malignant feature; combined with ascites and irregular architecture it drives O-RADS 4–5 and gynae-oncology MDT referral.
Red flag: solid vascular mass + ascites + omental thickening → urgent gynae-oncology referral; add CA-125 and staging imaging.
Thyroid nodule — ACR TI-RADS
The ACR TI-RADS (2017) scores a nodule across five feature categories. Assign the single highest-point finding from each of composition, echogenicity, shape and margin, and add points for every echogenic-foci feature present. Sum the points → TR level → then apply the size-based FNA / follow-up rule. Measure the nodule’s maximum diameter. Points are summed as below.
| Category | Finding | Points |
|---|---|---|
| Composition | Cystic or almost completely cystic | 0 |
| Spongiform | 0 | |
| Mixed cystic and solid | 1 | |
| Solid or almost completely solid | 2 | |
| Echogenicity | Anechoic | 0 |
| Hyperechoic or isoechoic | 1 | |
| Hypoechoic | 2 | |
| Very hypoechoic | 3 | |
| Shape | Wider-than-tall | 0 |
| Taller-than-wide | 3 | |
| Margin | Smooth | 0 |
| Ill-defined | 0 | |
| Lobulated or irregular | 2 | |
| Extra-thyroidal extension | 3 | |
| Echogenic foci (add all that apply) | None or large comet-tail artefacts | 0 |
| Macrocalcifications | 1 | |
| Peripheral (rim) calcifications | 2 | |
| Punctate echogenic foci | 3 |
Take the highest single point value from each of the first four categories; sum the points from all echogenic-foci features present.
| Level | Total points | Risk descriptor | Management |
|---|---|---|---|
| TR1 | 0 | Benign | No FNA |
| TR2 | 2 | Not suspicious | No FNA |
| TR3 | 3 | Mildly suspicious | FNA if ≥2.5 cm; follow up if ≥1.5 cm |
| TR4 | 4–6 | Moderately suspicious | FNA if ≥1.5 cm; follow up if ≥1.0 cm |
| TR5 | ≥7 | Highly suspicious | FNA if ≥1.0 cm; follow up if ≥0.5 cm |
Note: a total of 1 point (which would fall between TR1 and TR2) is classified as TR2. Follow-up of nodules not meeting FNA thresholds is by serial ultrasound at ACR-recommended intervals. Cut-offs may differ under other systems (ATA, EU-TIRADS, K-TIRADS) — state which you are using.
Worked example — the “why does TR matter” pattern Illustrative
= 13 points → TR5. FNA if ≥1 cm. This is the classic papillary-carcinoma pattern.
= 1 point → TR2, no FNA. Spongiform and purely cystic nodules are almost always benign.
- Taller-than-wide shape, punctate echogenic foci (microcalcifications), very hypoechoic solid tissue and irregular/ETE margins each add 3 (or 2) points and are the malignant hallmarks.
- Spongiform composition and pure cyst are the reassuring extremes (0 points).
- Punctate foci in a mixed cystic-solid nodule may represent colloid — some evidence supports scoring them lower; apply local practice.
Breast lesion — BI-RADS ultrasound
Describe every solid or complex lesion using the BI-RADS 5th-edition ultrasound lexicon (shape, orientation, margin, echo pattern, posterior features) — the descriptors, taken together, drive the final assessment category and its management. The lexicon is harmonised across mammography, ultrasound and MRI. Below: the descriptor set, then the category → management table.
| Feature | Favours benign | Favours malignancy |
|---|---|---|
| Shape | Oval (or round) | Irregular |
| Orientation | Parallel (wider-than-tall) | Not parallel (taller-than-wide) |
| Margin | Circumscribed | Not circumscribed: indistinct, angular, microlobulated, spiculated |
| Echo pattern | Anechoic; hyperechoic; some complex cystic-and-solid | Hypoechoic; heterogeneous |
| Posterior features | Enhancement (or none) | Shadowing; combined pattern |
Also assess associated features (architectural distortion, duct changes, skin thickening/retraction, oedema, vascularity, elasticity) and calcifications. A simple cyst (anechoic, circumscribed, posterior enhancement, no flow) is BI-RADS 2.
| Category | Meaning | Likelihood of cancer | Management |
|---|---|---|---|
| 0 | Incomplete | n/a | Additional imaging (± prior films) |
| 1 | Negative | essentially 0% | Routine screening |
| 2 | Benign | essentially 0% | Routine screening |
| 3 | Probably benign | >0% to ≤2% | Short-interval follow-up (usually 6 months) |
| 4 | Suspicious (4A low · 4B moderate · 4C high) | >2% to <95% | Tissue diagnosis (biopsy) |
| 5 | Highly suggestive of malignancy | ≥95% | Biopsy & treatment |
| 6 | Known biopsy-proven malignancy | — | Treatment as appropriate |
Category 4 sub-divisions: 4A ~2–10%, 4B ~10–50%, 4C ~50–<95% (approximate). The category must reflect the whole examination (US + mammography where available), not a single descriptor.
Simple cyst BI-RADS 2
Anechoic, circumscribed, oval, thin wall, posterior enhancement, no internal flow.
Purely anechoic + no solid component/flow = benign cyst. Internal echoes/septa → complicated or complex cyst (may warrant aspiration/biopsy).
Fibroadenoma Typically BI-RADS 3 (or 2)
Oval, parallel orientation, circumscribed margin, homogeneous hyp/isoechoic, ± posterior enhancement, ≤3 gentle macrolobulations.
All-benign descriptors (oval + parallel + circumscribed) → probably benign. Any suspicious descriptor upgrades to 4 → biopsy.
Invasive carcinoma BI-RADS 4–5
Irregular shape, not-parallel orientation, spiculated / non-circumscribed margin, markedly hypoechoic, posterior shadowing, ± architectural distortion, skin/duct changes.
Taller-than-wide + spiculated margin + posterior shadowing is the classic malignant triad → BI-RADS 4C/5 → biopsy irrespective of size.
Red flag: spiculated, taller-than-wide, shadowing mass with skin/nipple retraction or a suspicious axillary node → expedite triple assessment.
Scrotal — acute & mass
The pivotal question in the acute scrotum is colour-Doppler flow: absent/reduced intratesticular flow in a painful testis is torsion until proven otherwise and a surgical emergency, whereas increased flow points to inflammation. Always compare with the asymptomatic side using identical Doppler settings (low PRF, high colour gain, low wall filter) and use spectral Doppler to confirm arterial flow. For a palpable mass, the key split is intratesticular (malignant until proven otherwise) vs extratesticular (usually benign).
Testicular torsion Surgical emergency
Early: may be normal or an enlarged, heterogeneous, hypoechoic testis; twisted “whirlpool” of the cord above the testis; reactive hydrocele/skin thickening.
Absent or markedly reduced intratesticular flow vs the normal side. Whirlpool sign of the spermatic cord. Partial/intermittent torsion may show reduced or paradoxically preserved flow — do not be reassured by any flow if the history fits.
- Reduced/absent intratesticular Doppler flow in a painful, high-riding testis = torsion. This is time-critical — do not delay surgical exploration for equivocal imaging.
- Optimise Doppler (low PRF/scale, high gain, low filter) and always compare sides; use power Doppler / spectral trace to confirm true absence of flow.
Red flag: acute severe pain + absent intratesticular flow → immediate urology; the testis salvage window is roughly <6 hours.
Epididymo-orchitis Inflammatory
Enlarged, hypoechoic, heterogeneous epididymis ± testis; reactive hydrocele; scrotal wall thickening.
Increased flow (hyperaemia) in the epididymis/testis — the opposite of torsion.
- Hyperaemia on colour Doppler with a swollen tender epididymis and gradual-onset pain/pyrexia/dysuria favours infection. Beware: a missed/late torsion can also become hyperaemic after detorsion or with infarct rim — correlate with onset and history.
- Watch for complications: abscess (avascular collection), or a focal avascular area = infarct.
Testicular tumour Malignant until proven otherwise
Intratesticular solid mass — seminoma often homogeneous hypoechoic; non-seminomatous germ-cell tumours heterogeneous with cysts/calcification.
Internal vascularity (though small lesions may appear avascular).
- Any solid intratesticular lesion is malignant until proven otherwise → tumour markers (AFP, β-hCG, LDH) and urology referral. Location is decisive: intratesticular = concern; extratesticular = usually benign.
- Benign mimics: intratesticular cyst, tunica albuginea cyst, epidermoid (“onion-ring”), segmental infarct — but treat solid vascular lesions as tumour.
Hydrocele / varicocele / other extratesticular Usually benign
Hydrocele: anechoic fluid around the testis. Varicocele: serpiginous tubular veins >2–3 mm in the pampiniform plexus. Epididymal cyst/spermatocele: extratesticular anechoic cyst.
Varicocele: venous flow that augments/reverses with Valsalva (or standing). Hydrocele/cysts: no flow.
- Varicocele confirmed by Valsalva augmentation of dilated pampiniform veins (left-sided predominance; a new right-sided or non-decompressing varicocele warrants abdominal imaging for a mass).
- Complex/septated or debris-filled hydrocele (pyocele/haematocele) needs clinical correlation.
Right-upper-quadrant / biliary
The fasted RUQ ultrasound answers a chain of questions: are there gallstones? Is there acute cholecystitis (wall thickening, pericholecystic fluid, sonographic Murphy sign)? Is the CBD dilated or is there a stone within it? And is a gallbladder wall lesion a benign polyp or a carcinoma? A contracted, non-fasted gallbladder mimics wall thickening and hides stones — always confirm fasting.
Cholelithiasis (gallstones) Common
Echogenic focus/foci in the gallbladder lumen with clean posterior acoustic shadowing, mobile and gravity-dependent.
Mobility + posterior shadowing. A GB packed with stones = “WES/double-arc-shadow” sign (wall–echo–shadow).
- Mobile echogenic focus + clean shadow = stone; differentiate from a polyp (fixed, no shadow) and sludge (mobile, no shadow, low-level echoes).
- Roll the patient to demonstrate mobility; focus at the posterior wall to sharpen the shadow.
Acute cholecystitis Acute
Gallstone(s) (usually impacted in neck) + GB wall >3 mm ± wall striation/oedema + pericholecystic fluid + GB distension.
Positive sonographic Murphy sign — maximal tenderness when the probe is pressed over the sonographically localised gallbladder.
- The combination of stones + wall >3 mm + pericholecystic fluid + positive sonographic Murphy is highly specific for acute cholecystitis. Wall thickening alone is non-specific (also hepatitis, heart failure, ascites, hypoalbuminaemia, non-fasted GB).
- Beware gangrenous cholecystitis (irregular/asymmetric wall, intraluminal membranes, absent Murphy if the wall is denervated) and gas in the wall/lumen (emphysematous — surgical emergency).
Red flag: gas in the GB wall (emphysematous), sloughed membranes/perforation, or an acalculous distended GB in a critically ill patient → urgent surgical referral.
Choledocholithiasis / CBD obstruction Obstructive
Dilated CBD (>6–7 mm; allow +1 mm/decade >60 y and up to ~10 mm post-cholecystectomy) ± an echogenic shadowing stone in the duct; dilated intrahepatic ducts (“too many tubes”/parallel-channel sign).
Duct dilatation proximal to an obstructing stone; colour Doppler confirms the tubular structure is duct (no flow) not artery.
- A dilated CBD ± visualised stone, especially with deranged LFTs, points to choledocholithiasis → MRCP/EUS/ERCP. The distal duct is often obscured by duodenal gas — a normal-calibre duct does not exclude a stone.
- Painless progressive dilatation with a mass at the head of pancreas / “double-duct sign” raises concern for malignant obstruction.
Gallbladder polyp vs carcinoma Wall lesion
Polyp: fixed, non-mobile, non-shadowing wall projection (cholesterol polyps often <10 mm, echogenic, may show comet-tail in adenomyomatosis). Carcinoma: irregular focal wall thickening or a fungating mass, often >10 mm, ± invasion of liver, ± stones.
Size & growth: a polyp ≥10 mm, rapid growth, broad base, vascularity or age/PSC risk factors raises concern for malignancy.
- Fixed + non-shadowing separates a polyp from a stone. Size ≥10 mm, sessile morphology, internal vascularity and interval growth shift toward carcinoma → surgical opinion / cross-sectional imaging.
- Adenomyomatosis: focal/diffuse wall thickening with intramural cystic spaces and “comet-tail” (twinkling) artefact — benign.
Renal & other
The renal ultrasound sorts obstruction (hydronephrosis, graded by the degree of pelvicalyceal dilatation and cortical loss) from parenchymal disease and from focal masses. For a cystic renal lesion, the Bosniak classification is defined on CT/MRI — ultrasound cannot reliably assign a Bosniak category (it under-detects thin septa and enhancement), so a complex cystic lesion on US should be characterised with contrast-enhanced CT/MRI or CEUS.
| Grade | Sonographic appearance |
|---|---|
| Mild (I) | Splitting of the central echo complex / slight pelvic dilatation; calyces not dilated; normal cortex. |
| Moderate (II–III) | Dilated renal pelvis with dilated calyces (rounded/ballooned fornices); cortex preserved. |
| Severe (IV) | Gross pelvicalyceal dilatation with ballooned calyces and cortical thinning. |
Correlate with a full bladder and post-void status (a full bladder can cause mild bilateral pelvicalyceal fullness). Look for the obstructing cause — ureteric/PUJ calculus (twinkle artefact on colour Doppler), and check ureteric jets. Grading nomenclature varies (SFU vs UTD); state the system used.
Simple renal cyst Benign
Anechoic, thin imperceptible wall, round, posterior enhancement, no septa/solid component/flow.
Meets all simple-cyst criteria = benign (Bosniak I equivalent, but the category is formally a CT/MRI call). Any wall thickening, septa, calcification or solid nodule → complex → cross-sectional imaging.
Angiomyolipoma (AML) Usually benign
Well-defined, markedly hyperechoic (as bright as renal sinus fat) cortical lesion, ± posterior shadowing.
Uniform bright echogenicity suggests fat (AML) — but a small renal cell carcinoma can also be hyperechoic, so a hyperechoic lesion is not definitively benign on US. Confirm macroscopic fat on CT/MRI (except fat-poor AML).
Solid renal mass / RCC Concern for malignancy
Solid, variable echogenicity, may have cystic/necrotic areas; internal vascularity on colour/CEUS; may bulge the contour.
Any solid, vascular, non-fat-containing renal mass is a renal cell carcinoma until proven otherwise → contrast-enhanced CT/MRI for characterisation and staging (renal vein/IVC thrombus).
Red flag: solid enhancing renal mass with tumour extension into the renal vein/IVC → urgent urology referral and staging.
Complex cystic renal lesion — the Bosniak-on-US caveat Indeterminate
Septa, wall thickening, calcification, or solid/enhancing components within a cystic lesion.
Ultrasound detects septa and calcification but cannot assess enhancement — the pillar of Bosniak grading. A complex cystic lesion on US must be characterised on contrast CT/MRI (or CEUS in expert hands); do not assign a definitive Bosniak category from grey-scale US alone.
Structured reporting templates, full scoring calculators & image banks — Pro
Pro members get interactive point/category calculators for every system on this page (ACR TI-RADS, O-RADS US v2022 with management, BI-RADS 5th ed., IOTA Simple Rules & ADNEX, hydronephrosis grading), copy-paste structured report macros, side-by-side “benign vs malignant” image comparison banks for each scenario, CEUS phase atlases, and printable bedside decision cards. Also included: paediatric and POCUS adaptation packs, and the accreditation-aligned worksheet library.
Explore High Yield Ultrasound Pro →References & further reading
- Tessler FN, Middleton WD, Grant EG, et al. ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee. J Am Coll Radiol 2017;14(5):587–595. jacr.org.
- American College of Radiology. ACR TI-RADS — Reporting and Data Systems (current calculator & committee resources). acr.org/TI-RADS.
- Hoang JK, Middleton WD, Tessler FN. Thyroid Imaging Reporting and Data System (TI-RADS): A User’s Guide. Radiology 2018;287(1):29–36. doi:10.1148/radiol.2017171240.
- The Radiology Assistant. TI-RADS — Thyroid Imaging Reporting and Data System. radiologyassistant.nl.
- Andreotti RF, Timmerman D, Strachowski LM, et al. O-RADS US Risk Stratification and Management System: A Consensus Guideline from the ACR Ovarian-Adnexal Reporting and Data System Committee. Radiology 2020;294(1):168–185.
- Strachowski LM, Jha P, Phillips CH, et al. O-RADS US v2022: An Update from the ACR Ovarian-Adnexal Reporting and Data System US Committee. Radiology 2023;308(3):e230685. doi:10.1148/radiol.230685.
- American College of Radiology. O-RADS Ultrasound — Reporting and Data Systems. acr.org/O-RADS.
- Timmerman D, Testa AC, Bourne T, et al. Simple ultrasound-based rules for the diagnosis of ovarian cancer. Ultrasound Obstet Gynecol 2008;31(6):681–690.
- Timmerman D, Ameye L, Fischerova D, et al. Simple ultrasound rules to distinguish between benign and malignant adnexal masses before surgery: prospective validation by IOTA group. BMJ 2010;341:c6839. PMID 21156740.
- Meys EMJ, Kaijser J, Kruitwagen RFPM, et al. IOTA Simple Rules: Review of 10 Points for Evaluation of Adnexal Masses. RadioGraphics 2021. rsna RadioGraphics.
- American College of Radiology. BI-RADS Atlas, 5th edition — Breast Ultrasound (lexicon, assessment categories & management). acr.org/BI-RADS.
- Spak DA, Plaxco JS, Santiago L, et al. BI-RADS fifth edition: A summary of changes. Diagn Interv Imaging 2017;98(3):179–190. sciencedirect.
- Mendelson EB, Böhm-Vélez M, Berg WA, et al. ACR BI-RADS Ultrasound. In: ACR BI-RADS Atlas, 5th ed. ACR, 2013.
- Rumack CM, Levine D (eds). Diagnostic Ultrasound, 5th edn. Elsevier, 2018 (liver, biliary, renal, scrotal and gynaecologic chapters).
- Dietrich CF, Nolsøe CP, Barr RG, et al. WFUMB/EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in the Liver — Update 2020. Ultraschall Med 2020;41(5):562–585.
- American Institute of Ultrasound in Medicine (AIUM). Practice Parameters — abdomen/retroperitoneum, female pelvis, scrotum, thyroid/parathyroid. aium.org — official statements.
- Royal College of Radiologists (RCR) / British Medical Ultrasound Society (BMUS). Guidance on the imaging of gallbladder polyps and common bile duct and professional ultrasound practice. bmus.org.
- Wiles R, Thoeni RF, Barbu ST, et al. Management and follow-up of gallbladder polyps: joint guidelines (ESGAR/EAES/EFISDS/ESGE). Eur Radiol 2017;27:3856–3866.
- Silverman SG, Pedrosa I, Ellis JH, et al. Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment. Radiology 2019;292(2):475–488 (Bosniak is a CT/MRI classification).
- Onur MR, Poyraz AK, Ucak EE, et al. Semiquantitative and qualitative assessment of hydronephrosis; and Society for Fetal Urology (SFU) / Urinary Tract Dilation (UTD) grading references.
- Radiopaedia.org — reference articles: focal liver lesions, hepatic haemangioma, focal nodular hyperplasia, hepatocellular carcinoma, liver metastases, adnexal mass, O-RADS, ACR TI-RADS, BI-RADS, testicular torsion, epididymo-orchitis, testicular tumour, acute cholecystitis, choledocholithiasis, gallbladder polyp, hydronephrosis, angiomyolipoma, renal cell carcinoma. radiopaedia.org.
- Society of Radiologists in Ultrasound (SRU). Consensus statements — thyroid nodule and gallbladder polyp management. sru.org.