ABR IR/DR key terms

Method of gaining vascular access by puncturing a vessel with a needle, passing a guidewire through the needle, removing the needle, and then advancing a catheter over the wire.

Variant of vascular access using a thin 21-gauge needle and a short fine guidewire, then serial dilation, chosen when a vessel is small or difficult to palpate.

Flexible wire placed through a needle or catheter to maintain access and direct passage of devices; described by diameter, length, tip shape, and stiffness.

Guidewire coated to become very slippery when wet, useful for navigating tortuous or stenotic vessels but prone to dislodging if not kept wet and controlled.

Delivery of a clot-dissolving drug directly into a thrombus through a catheter positioned within the vessel, used for deep vein thrombosis or arterial occlusion.

Combined approach to clot removal that pairs catheter-delivered lytic agent with a mechanical device that macerates or aspirates thrombus in the same session.

Chronic leg pain, swelling, and skin changes that develop after deep vein thrombosis because of persistent venous obstruction or valve damage.

Compression of the left common iliac vein between the right common iliac artery and the spine, predisposing to left leg deep vein thrombosis.

Self-expanding metallic stent placed in a compressed or stenosed iliac vein to restore outflow; large diameter and high radial force are typical requirements.

Stent tract created between a hepatic vein and a portal vein branch to decompress portal hypertension, most often for refractory variceal bleeding or ascites.

Neuropsychiatric dysfunction caused by shunting of gut-derived toxins past the liver; a major complication after portosystemic shunt creation.

Elevated pressure in the portal venous system, usually from cirrhosis, producing varices, ascites, and splenomegaly.

Liver-directed therapy in which resin or glass microspheres carrying beta-emitting yttrium-90 are infused into hepatic arteries to treat tumor while sparing normal parenchyma.

Delivery of chemotherapy mixed with embolic material into tumor-feeding arteries, combining local drug effect with ischemia; used mainly for hepatocellular carcinoma.

Arterial embolization without a chemotherapeutic agent, used to devascularize tumors or control bleeding.

Passage of infused particles from the hepatic circulation into pulmonary capillaries; assessed before radioembolization because excessive lung dose can cause radiation pneumonitis.

Catheter occlusion of both uterine arteries with particles to shrink symptomatic fibroids and relieve bleeding or bulk symptoms.

Benign smooth-muscle tumor of the uterus that can cause heavy bleeding, pain, or mass effect and is a common indication for uterine artery embolization.

Percutaneous occlusion of an incompetent gonadal vein, usually on the left, to treat scrotal swelling or male infertility related to varicocele.

Vein draining the ovary or testis; the left gonadal vein joins the left renal vein while the right drains directly into the inferior vena cava.

Catheter placed through the flank into the renal collecting system to drain obstructed urine or provide access for stone procedures.

Tube placed within the ureter, often with a pigtail at each end, to maintain urine flow past an obstruction or stricture.

Injection of contrast through a nephrostomy tube or needle into the collecting system to outline the renal pelvis and ureter.

Tube placed percutaneously into the bile ducts to relieve jaundice or cholangitis when endoscopic access fails.

Opacification of the bile ducts by needle puncture of a peripheral intrahepatic duct under imaging guidance, used to diagnose and plan biliary intervention.

Thermal tumor destruction using alternating current delivered through an electrode, producing coagulative necrosis in a small targeted volume.

Thermal ablation using electromagnetic energy that heats tissue faster than radiofrequency and is less affected by char or nearby vessels.

Ring of normal tissue around a treated tumor that should also be destroyed; an adequate margin lowers the risk of local recurrence.

Metallic device placed in the inferior vena cava to trap emboli from leg veins when anticoagulation is contraindicated or has failed.

Occlusion of pulmonary arteries by thrombus, usually arising from leg veins; presents with dyspnea and is a target of prevention by caval filtration.

Quantitative scale of CT attenuation in which water is zero and air is about minus 1000, used to characterize tissue and confirm contrast enhancement.

Contrast-enhanced CT timed to opacify pulmonary arteries, the first-line test for suspected pulmonary embolism.

Display settings that set the range and center of CT attenuation values mapped to visible gray shades, controlling contrast and brightness on the image.

Time constant describing recovery of longitudinal magnetization after an radiofrequency pulse; tissues with short T1 appear bright on T1-weighted images.

Time constant describing decay of transverse magnetization from spin-spin interactions; long T2 tissues such as fluid appear bright on T2-weighted images.

Paramagnetic contrast agent that shortens T1 relaxation and brightens tissues on T1-weighted MRI; free gadolinium is toxic and must be tightly bound.

Scleroderma-like fibrosing disorder of skin and organs linked to gadolinium exposure in patients with severe renal impairment.

MRI sequence sensitive to microscopic water motion; restricted diffusion appears bright and helps detect acute infarction, abscess, and dense cellular tumor.

Calculated image derived from diffusion-weighted data that removes T2 shine-through and shows restricted diffusion as low signal.

Energy deposited per unit mass of tissue, expressed in gray, used to estimate deterministic and stochastic risk from fluoroscopic procedures.

Product of air kerma and beam area at a point, a fluoroscopy dose index that reflects total radiation delivered independent of field size.

Tissue injury such as skin erythema that appears only above a threshold dose and whose severity rises with dose.