Differential diagnosis
Search an imaging pattern or finding and get a ranked list of differentials, each with the discriminating features that point toward it. Every gamut also carries the cross-cutting key discriminators that split it and a suggested next-step work-up.
Solitary pulmonary nodule
A single, rounded opacity ≤3 cm surrounded by aerated lung. Management is driven by malignancy probability from morphology, growth and smoking/age risk.
6 differentials
Multiple pulmonary nodules
Numerous discrete nodules. Distribution (random, perilymphatic, centrilobular) and clinical setting narrow the differential considerably.
6 differentials
Cavitary lung lesion
A gas-containing space within a nodule/mass or consolidation. Wall thickness and clinical acuity are the strongest predictors of aetiology.
6 differentials
Anterior mediastinal mass (the 4 T’s)
A prevascular (anterior) compartment mass. The classic "4 T’s" (thymic, teratoma/germ cell, thyroid, terrible lymphoma) plus age and tumour markers direct work-up.
6 differentials
Ring-enhancing brain lesion
A lesion with peripheral (rim) enhancement and a non-enhancing centre. Diffusion, wall morphology and number/location are decisive.
6 differentials
Multiple T2 white-matter lesions (MS vs mimics)
Multiple T2/FLAIR hyperintensities in cerebral white matter. Distribution and morphology separate demyelination from small-vessel and other mimics.
6 differentials
Cerebellopontine angle mass
A mass in the CPA cistern presenting with hearing loss, tinnitus or facial symptoms. Relationship to the internal auditory canal and signal characteristics are key.
6 differentials
Sellar / suprasellar mass
A mass centred on the sella or suprasellar cistern, often presenting with visual field defects or endocrinopathy. Epicentre and patient age drive the differential.
6 differentials
Liver lesion in cirrhosis
A nodule detected in a cirrhotic liver. Hepatocellular carcinoma is presumed until proven otherwise; LI-RADS classifies risk by enhancement dynamics.
6 differentials
Hypervascular liver lesions
Lesions showing arterial-phase hyperenhancement in a non-cirrhotic liver. Enhancement pattern on later phases and clinical history distinguish benign from malignant.
6 differentials
Adrenal mass
An incidental or symptomatic adrenal lesion. Unenhanced attenuation, chemical-shift signal loss and enhancement washout separate the common benign adenoma from other entities.
6 differentials
Solid enhancing renal mass
An enhancing (>20 HU) soft-tissue renal lesion. Presence of macroscopic fat and enhancement pattern separate benign entities from renal cell carcinoma subtypes.
6 differentials
Bladder wall thickening
Thickening of the bladder wall, focal or diffuse. Focality, enhancement and clinical context (outflow obstruction, infection) direct the differential.
6 differentials
Adnexal cystic mass
A cystic lesion of the ovary/adnexa. Internal content, wall/septal thickness and vascularity (O-RADS) stratify malignancy risk.
6 differentials
Lytic bone lesion
A radiolucent bone lesion. Patient age is the single most useful discriminator; zone of transition and periosteal reaction indicate aggressiveness.
6 differentials
Sclerotic (blastic) bone lesions
Areas of increased bone density, single or multiple. Multiplicity and clinical context distinguish metastatic disease from benign and marrow-based causes.
6 differentials
Aggressive vs non-aggressive bone lesion
A framework rather than a single diagnosis: assessing the margin, periosteal reaction and cortical status to judge how biologically aggressive a bone lesion is.
5 differentials
Soft-tissue mass
A mass in the soft tissues. Most are benign; specific signal characteristics (fat, fluid, flow voids) allow confident diagnosis, while non-specific solid masses need biopsy.
6 differentials
Small bowel obstruction
Dilated small bowel (>3 cm) with a transition point and collapsed distal loops. The task is to find the cause at the transition and exclude ischaemia.
6 differentials
Pneumoperitoneum (causes)
Free intraperitoneal gas. Most cases reflect a perforated viscus needing surgery; recent surgery and other non-surgical causes must be recognised to avoid unnecessary laparotomy.
6 differentials
Splenic lesion(s)
Focal splenic lesion(s), usually incidental. Most are benign; multiplicity, enhancement and systemic context guide characterisation.
6 differentials
Pancreatic cystic lesion
A cystic pancreatic lesion. Communication with the duct, cyst architecture and demographics separate benign from mucinous (premalignant) lesions.
6 differentials
Widened mediastinum
Mediastinal widening on a chest radiograph (>8 cm on supine AP). The urgent task is to exclude acute aortic injury while considering technical and mass causes.
6 differentials
Bilateral hilar lymphadenopathy
Symmetric enlargement of both hila. Symmetry, associated parenchymal pattern and clinical context distinguish sarcoidosis from infective and malignant causes.
6 differentials