ABR Neuroradiology flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

ADC pseudonormalization

At roughly 7-10 days after infarction, ADC values rise back toward normal, so a subacute infarct can appear bright on both DWI and ADC maps.

Hyperdense MCA sign

Noncontrast CT finding of a bright proximal MCA due to acute thrombus; it indicates large-vessel occlusion and correlates with severe ischemia.

ASPECTS score

A 10-point CT score subtracting one point for each involved MCA territory region; lower scores indicate larger infarct burden and poorer outcome.

Intracellular methemoglobin

Early subacute hemorrhage stage with T1 hyperintensity and T2 hypointensity, reflecting intact red blood cells containing oxidized hemoglobin.

Abscess versus tumor

Restricted diffusion in the enhancing rim favors abscess; elevated perfusion and spectroscopy showing high choline with low NAA favor high-grade neoplasm.

PRES imaging pattern

Bilateral parieto-occipital white matter T2/FLAIR hyperintensity reflecting vasogenic edema, usually without restricted diffusion, often related to hypertension or medications.

Cerebral amyloid angiopathy

Lobar microbleeds, cortical superficial siderosis, and lobar hemorrhage in older adults, with sparing of deep gray nuclei and brainstem.

HSV encephalitis pattern

Asymmetric T2 hyperintensity of medial temporal lobes, insula, and inferior frontal lobes with basal ganglia sparing; restricted diffusion and enhancement are common.

Transependymal edema

Periventricular T2/FLAIR hyperintensity from CSF transependymal flow, supporting active hydrocephalus rather than ex vacuo ventricular enlargement.

Colloid cyst location

A well-circumscribed round cyst at the anterior third ventricle near the foramen of Monro; it can obstruct CSF flow and cause acute hydrocephalus.

Modic type 1

Vertebral endplate signal that is T1 dark and T2 bright, representing marrow edema and often associated with painful degenerative disc disease.

Spondylodiscitis MRI signs

Disc space narrowing with T2 hyperintensity of the disc and adjacent endplates, endplate irregularity, and enhancement suggesting infection.

Cauda equina red flags

Saddle anesthesia, bowel or bladder dysfunction, or bilateral leg weakness warrant urgent MRI to exclude compressive disc extrusion or epidural collection.

Myelomeningocele

A posterior neural tube defect in which the neural placode and meninges protrude through the bony defect, unlike a meningocele that contains only meninges.

Syrinx signal

A central cavity within the spinal cord that follows CSF signal on T1 and T2 and does not enhance, often accompanying Chiari malformation.

Benign compression fracture

Preserved posterior vertebral cortex with band-like marrow edema and a low-signal fracture line; pedicle involvement or epidural mass suggests malignancy.

Transverse myelitis

Central cord T2 hyperintensity spanning multiple segments with swelling, often with enhancement during active inflammation; consider demyelination and neuromyelitis optica.

Cord compression assessment

Axial T2 images best show cord flattening, deformation, and loss of surrounding CSF, which define the severity of degenerative canal stenosis.

Prestyloid versus poststyloid

The parapharyngeal fat plane displaces to reveal origin; prestyloid masses are usually salivary or fat, while poststyloid masses are neurogenic or vascular.

Juvenile angiofibroma

Adolescent male with epistaxis and a sphenopalatine foramen mass that enhances avidly, shows flow voids, and widens the pterygopalatine fossa.

Nodal size staging

In head and neck squamous cell carcinoma, nodes larger than 3 cm are N2 and nodes larger than 6 cm are N3; extranodal extension upstages.

Cholesteatoma MRI

Middle ear soft tissue with bony erosion that restricts diffusion on non-EPI DWI and does not enhance centrally, distinguishing it from postoperative granulation.

Orbital cellulitis

Postseptal infection with proptosis and restricted extraocular movement; it risks cavernous sinus thrombosis and subperiosteal or orbital abscess.

Warthin tumor

A benign parotid tumor that is often bilateral, cystic, and located in the parotid tail, typically occurring in older men.

Pleomorphic adenoma

The most common benign parotid tumor; it is well circumscribed and markedly T2 bright, with slow enhancement and possible lobulated margins.

Perineural spread

Tumor tracking along cranial nerves V or VII, seen as nerve thickening and enhancement with widening of the foramen ovale or stylomastoid foramen.

Thyroid suspicious nodule

Irregular margins, microcalcifications, taller-than-wide shape, and marked hypoechogenicity raise malignancy risk and guide fine-needle aspiration by size.

Retropharyngeal space

A space between the buccopharyngeal and alar fasciae; fluid or mass here can spread infection to the mediastinum and requires urgent evaluation.

Laryngeal cartilage invasion

Tumor breaching the outer thyroid cartilage cortex or invading through cartilage upstages laryngeal cancer; cartilage sclerosis alone is not reliable.

Parapharyngeal fat displacement

Medial displacement of parapharyngeal fat suggests a mass arising from the deep parotid lobe or masticator space rather than from the mucosa.

Sinonasal inverted papilloma

A benign but locally aggressive sinonasal mass with a cerebriform or laminated pattern on MRI, often centered at the middle meatus and capable of malignant transformation.

Spinal epidural abscess

A enhancing epidural collection compressing the cord or cauda equina, often with adjacent spondylodiscitis; it is a surgical emergency when neurologic deficits are present.