ABR (NAR) key terms

Splits suspicious breast findings into 4A (low suspicion, 2-10% malignant), 4B (moderate, 10-50%), and 4C (high, 50-95%), guiding whether biopsy or short-interval follow-up is appropriate.

A probably benign breast finding with under 2% likelihood of malignancy, managed by short-interval follow-up rather than immediate biopsy; assigned only when the lesion has a classic, well-described appearance.

Percutaneous breast tissue sampling using mammographic triangulation of a lesion seen in two projections, typically chosen for microcalcifications or masses visible only on mammography and not by ultrasound.

A needle sampling technique that uses suction to draw tissue into a sampling aperture and can retrieve larger, contiguous specimens than automated core needles, often used for calcifications and complete removal of small lesions.

A computational technique that estimates lesion-specific coronary pressure ratios from a resting CT angiogram using modeled coronary flow, helping identify stenoses likely to cause ischemia without additional invasive testing.

A noncontrast CT measurement of calcified coronary plaque expressed as an Agatston score; a score of zero confers very low near-term cardiovascular risk, while higher scores stratify risk independently of conventional factors.

An MRI sequence acquired minutes after gadolinium administration that highlights areas of myocardial scar or fibrosis as bright signal, used to distinguish ischemic from nonischemic cardiomyopathy patterns.

The general MRI technique of imaging myocardium after gadolinium washout from normal tissue, producing high contrast between nulled normal myocardium and regions of expanded extracellular space such as scar.

Acquisition of CT data at two photon energy spectra, allowing material decomposition into maps such as iodine, water, or calcium and improving characterization of stones, gout crystals, and enhancing lesions.

Reconstructed CT images simulating acquisition at a single photon energy; low keV images boost iodine contrast while high keV images reduce metal artifact, both derived from dual-energy acquisition data.

A single-acquisition CT protocol that gives a divided contrast dose so that opacified collecting systems and enhanced renal parenchyma appear on one scan, reducing radiation compared with multiphase urography.

Dark streaks or cupping on CT caused by preferential absorption of low-energy photons as the beam traverses dense material, producing a spectrum that is harder and less attenuating than expected.

A standardized system for reporting liver observations in patients at risk for hepatocellular carcinoma, using major features such as arterial phase hyperenhancement, washout, and capsule to assign categories from LR-1 to LR-5.

The combination of arterial phase hyperenhancement with portal venous or delayed phase washout, sometimes with capsule or threshold growth, that permits noninvasive diagnosis of HCC in a cirrhotic liver.

A CT or MRI acquisition timed roughly 60-80 seconds after contrast injection, when hepatic parenchyma enhances maximally via portal inflow and hepatic veins are opacified, useful for detecting hypovascular liver lesions.

A layered appearance of the bowel wall on contrast-enhanced imaging reflecting mucosal hyperenhancement, submucosal edema, and muscularis enhancement, a hallmark of active inflammatory bowel disease.

A CT technique using large volumes of neutral oral contrast and intravenous contrast to distend small bowel loops, improving detection of strictures, fistulas, and active inflammation in Crohn disease.

A cystic renal mass categorization based on wall thickness, septation, calcification, and solid or enhancing components, ranging from simple benign cysts to clearly malignant cystic neoplasms requiring surgery.

A measured increase in CT attenuation after contrast, commonly about 15-20 HU, used to distinguish truly enhancing solid renal lesions from nonenhancing cysts, though pseudoenhancement can confound small cysts.

A structured reporting system for prostate MRI that scores lesions on multiparametric sequences, with diffusion-weighted imaging dominant in the peripheral zone and dynamic contrast and T2 weighting contributing by zone.

High signal on high b-value diffusion-weighted images with corresponding low apparent diffusion coefficient, a marker of dense cellularity that drives PI-RADS scoring in the peripheral zone.

Catheter delivery of yttrium-90 microspheres into hepatic arteries supplying tumor, producing localized beta irradiation; pretreatment mapping with macroaggregated albumin assesses lung shunt fraction and extrahepatic flow.

Image-guided infusion of chemotherapy emulsion into tumor-feeding arteries followed by embolic material, producing combined cytotoxic and ischemic effect for intermediate-stage hepatocellular carcinoma.

Temporary vessel occlusion using gelatin sponge particles mixed into a slurry, often for trauma, gastrointestinal bleeding, or preoperative devascularization, with recanalization expected over weeks.

Signal loss and geometric distortion on MRI near materials that alter local magnetic field homogeneity, such as metal implants, air, or hemosiderin, worsened by gradient echo sequences and long echo times.

MRI technique exploiting small resonance differences between fat and water protons; in-phase and opposed-phase imaging shows signal drop in voxels containing both, identifying microscopic fat in lesions such as adrenal adenomas.

A calculated MRI image derived from multiple diffusion-weighted acquisitions that removes T2 shine-through and quantifies water diffusivity, with low values suggesting restricted diffusion in cellular tumors or infarcts.

A three-tier MRI classification of intrameniscal signal: grade 1 is punctate, grade 2 is linear but does not reach an articular surface, and grade 3 reaches a surface and represents a true tear.

Secondary MRI findings supporting ACL rupture include bone contusions at the lateral femoral condyle and posterior tibial plateau, a deepened lateral femoral notch, and anterior tibial translation.

The space between the supraspinatus and subscapularis tendons containing the long head of biceps tendon and coracohumeral ligament; abnormalities here help explain anterior shoulder pain and biceps instability.

A 10-point scale subtracting one point for each of ten brain regions showing early ischemic change on noncontrast CT, used to estimate infarct extent before reperfusion therapy.

Focal high attenuation along the proximal middle cerebral artery on noncontrast CT, reflecting acute thrombus, and an early indicator of large vessel occlusion before infarction becomes visible.

Posterior reversible encephalopathy syndrome, characterized by vasogenic edema typically in parieto-occipital white matter on MRI, associated with hypertension, eclampsia, and immunosuppressive drugs.

A tissue-weighted sum of absorbed doses across organs, expressed in sieverts, used to compare stochastic risk across imaging studies; a chest CT is roughly 5-10 mSv.

The two core principles of radiation protection: justification ensures a study's benefit outweighs its risk, and optimization keeps dose as low as reasonably achievable while preserving diagnostic quality.

A nuclear medicine study using technetium-99m sestamibi, often with delayed or SPECT/CT imaging, to localize a hyperfunctioning parathyroid adenoma before minimally invasive surgery.

Lymphoscintigraphy using radiolabeled colloid injected near a tumor to identify the first draining node, guiding limited lymph node sampling in breast cancer and melanoma.

A pediatric fracture pattern described as a Salter-Harris equivalent involving the metaphysis; the mnemonic covers types I through V and predicts growth disturbance risk, with higher grades carrying greater risk.

A common elbow fracture in children classified by displacement, with risk of brachial artery and median nerve injury; the posterior fat pad sign and anterior humeral line help confirm occult fractures.