ABR (NAR) flashcards

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

BI-RADS category 3 management

Probably benign finding with <2% malignancy risk; short-interval follow-up mammography is recommended, typically at 6 months, then every 6-12 months until stability is documented.

BI-RADS category 4 subdivision

Suspicious findings requiring biopsy; 4A low suspicion (2-10% malignancy), 4B moderate (10-50%), and 4C high (50-95%) guide management and communication but all warrant tissue sampling.

Coronary calcium score zero

An Agatston score of 0 indicates no detectable coronary calcification and confers very low near-term cardiovascular event risk, though noncalcified plaque may still be present.

Late gadolinium enhancement patterns

Subendocardial or transmural enhancement follows coronary territories and indicates infarction; mid-wall enhancement suggests nonischemic cardiomyopathy; epicardial enhancement suggests myocarditis.

CT pitch definition

Pitch equals table feed per gantry rotation divided by detector collimation; pitch greater than 1 reduces dose and may increase noise; pitch less than 1 increases dose.

Dual-energy CT applications

Dual-energy CT exploits different attenuation at low and high kilovoltage to create virtual noncontrast images, iodine maps, and material-specific images such as uric acid stone characterization.

LI-RADS LR-5 criteria

In a high-risk patient, LR-5 requires arterial phase hyperenhancement plus at least one of washout, enhancing capsule, or threshold growth, with size-adjusted criteria for smaller observations.

Acute cholecystitis ultrasound signs

Gallstones, gallbladder wall thickening greater than 3 mm, pericholecystic fluid, and a sonographic Murphy sign support acute cholecystitis; a HIDA scan showing nonvisualization is highly sensitive.

Bosniak classification category IIF

Minimally complex cystic renal mass with low malignant potential, such as a cyst with thin septa or minimal calcification; follow-up imaging is recommended to assess for progression.

Adrenal adenoma washout criteria

An adrenal mass with unenhanced attenuation below 10 Hounsfield units is likely a lipid-rich adenoma; absolute washout greater than 60% or relative washout greater than 40% supports adenoma.

Modified Seldinger technique

Vascular access using needle puncture, guidewire insertion, and catheter exchange over the wire; femoral access at the mid-femoral head reduces pseudoaneurysm and retroperitoneal hemorrhage risk.

Postembolization syndrome

Fever, pain, and nausea occurring after embolization, usually self-limited and managed supportively; it must be distinguished from abscess or infarction by clinical course and imaging.

Diffusion restriction on MRI

High signal on diffusion-weighted imaging with low signal on the apparent diffusion coefficient map, reflecting high cellularity or cytotoxic edema, as in tumors, abscesses, and acute infarction.

Nephrogenic systemic fibrosis risk

Associated with gadolinium-based contrast agents, particularly linear agents, in patients with severe renal impairment; macrocyclic agents are preferred when contrast is necessary in at-risk patients.

Osteosarcoma imaging features

Aggressive metaphyseal bone lesion in adolescents with medullary sclerosis, Codman triangle, and sunburst periosteal reaction; MRI defines extent and guides limb-salvage surgery.

ACL tear secondary signs

Bone contusions at the lateral femoral condyle and posterior tibial plateau, anterior tibial translation, and a pivot-shift injury pattern support the diagnosis of anterior cruciate ligament tear.

ASPECTS score

A 10-point CT score for early ischemic change in the middle cerebral artery territory; each affected region subtracts one point, and lower scores predict worse outcome and influence thrombectomy decisions.

McDonald criteria

Diagnostic criteria for multiple sclerosis requiring dissemination of lesions in space and time, demonstrated clinically or by MRI, with exclusion of alternative diagnoses.

RADPEER

A peer-review tool for radiology practices that scores interpretive discrepancies by clinical significance, aiming to improve system performance rather than punish individual radiologists.

Effective dose reference values

Natural background radiation is about 3 mSv per year; a chest radiograph is about 0.1 mSv; a chest CT is about 7 mSv; these values support risk communication with patients.

High-probability V/Q scan

In the PIOPED criteria, high probability requires two or more large mismatched segmental perfusion defects; a normal perfusion scan effectively excludes pulmonary embolism.

FDG PET limitations

FDG uptake is not tumor-specific and occurs in infection and inflammation; SUVmax is semiquantitative and influenced by blood glucose, lesion size, and scanner characteristics.

Pyloric stenosis ultrasound criteria

Pyloric muscle thickness greater than 3 mm and canal length greater than 15 mm in an infant with nonbilious projectile vomiting, typically presenting at 3 to 6 weeks of age.

Intussusception enema

Air or contrast enema is both diagnostic and therapeutic for ileocolic intussusception; ultrasound shows a target sign; perforation and peritonitis are contraindications to enema reduction.

Breast MRI screening indication

Annual screening MRI is recommended for BRCA mutation carriers, prior chest radiation before age 30, and lifetime risk of 20 to 25 percent or greater by validated models.

CAD-RADS category 4

Coronary CTA stenosis of 70 to 99 percent, subdivided 4A and 4B; it warrants consideration of invasive angiography or functional testing depending on symptoms and ischemia assessment.

CT urography split-bolus technique

A single acquisition after divided contrast administration combines nephrographic and excretory phases, reducing radiation dose while opacifying the collecting system for hematuria evaluation.

Crohn disease imaging features

Transmural inflammation with skip lesions, strictures, fistulae, and perianal involvement; MRI enterography assesses small bowel disease activity and complications without ionizing radiation.

PI-RADS v2.1 peripheral zone

Diffusion-weighted imaging is the dominant sequence for peripheral zone prostate cancer; a score of 4 or 5 indicates high or very high likelihood of clinically significant cancer.

TACE indication

Transarterial chemoembolization is indicated for intermediate-stage hepatocellular carcinoma (BCLC B) with preserved liver function and no extrahepatic spread or vascular invasion.

MR spectroscopy brain tumor

Elevated choline and decreased N-acetylaspartate indicate high-grade tumor; a lactate doublet suggests anaerobic metabolism; these metabolite ratios help characterize and grade lesions.

Salter-Harris fracture types

Types I through V describe physeal fractures: I through the physis, II through physis and metaphysis, III through physis and epiphysis, IV through both, and V crush injury.