A

A2C-- apical two chamber

A4C-- apical four chamber

Achalasia-- A tightening (or failure to relax) the sphincter muscles of the esophagus at the junction with the stomach resulting in dilation of the esophagus, often with an air-fluid level visible in the mid-esophagus on an upright chest X-ray.

Acute marginal branch-- (of the right coronary artery [RCA]). The acute marginal is a major diagonal branch of the RCA, running toward the apex along the inferior margin of the right ventricular free wall.

Acute marginal-- branch of the right coronary artery which supplies the right ventricular free wall myocardium and follows a path located along the diaphragm anteriorly.

Adenopathy-- enlargement and disease of the lymph glands (e.g. tonsils, nodes, etc.).

Aesthenic-- a body configuration which has a light bony frame, thin soft tissues and slightly taller body height

Air bronchogram-- bronchi are normally not visible on chest radiographs because air-filled bronchi are no more dense than the air-filled normal lung parenchyma surrounding them. When diseased lung tissue is filled with fluid the contrast between consolidated (fluid-filled) lung tissue and air-filled bronchi makes the bronchi visible on radiographs. These segments of visible bronchi are called air bronchograms.

Air bronchograms-- bronchi are normally not visible on chest radiographs because air-filled bronchi are no more dense than the air-filled normal lung parenchyma surrounding them. When diseased lung tissue is filled with fluid the contrast between consolidated (fluid-filled) lung tissue and air-filled bronchi makes the bronchi visible on radiographs. These segments of visible bronchi are called air bronchograms.

ALA-- apical long-axis

Alimentary tract-- the organs related to digestion such as the esophagus, stomach, and bowel.

Alimentary-- having to do with the digestive tract, or gut

Alveolar sacs-- the most distal hemispherical airspace where gas exchange with the pulmonary arterial capillaries occurs

Alveoli-- (plural of alveolus) the small sac-like air spaces at the end of the airway where gas exchange takes place between alveolar air and the pulmonary capillary blood.

AM-- Acute marginal branch of the right coronary artery, [RCA]. The acute marginal is a major diagonal branch of the RCA, running toward the apex along the inferior margin of the right ventricular free wall.

AMVL-- anterior mitral valve leaflet

Aneurysm-- ballooning or sac-like bulging of a blood vessel, as in an aortic aneurysm.

Angina-- pain in the chest or referred to the jaw or arm caused by insufficient bloodflow to the myocardium by coronary vessels which lack adequate diameter for supplying needed oxygenated blood.

Angiogram-- a radiographic technique which uses a higher atomic weight iodinated fluid injected into the bloodstream to produce locally greater radiodensity (lighter regions on the x-ray image)

Angstrom-- 10 to the exponent minus10th meters

Anteroseptal myocardial infarction-- irreversible ischemic damage to the left ventricular myocardium in the septum and anterior wall which are usually supplied by the left anterior descending artery and diagonal arteries from the left coronary artery.

Ao-- aortic or aorta

ANT-- anterior; usually referring to a view angle in diagnostic imaging.

Aorta-- The major artery of the body, that receives freshly-oxygenated blood from the left ventricle.

Aortic aneurysms-- marked dilation of the aorta with a balloon-like or fusiform configuration.

Aortic arch-- the ascending and then descending loop of major vessel that acts as a conduit for the left ventricular pumping chamber distributing oxygenated blood to the body

Aortic knob-- top of the aortic arch where the three major head vessels originate; i.e.: innominate artery, left common carotid, and left subclavian artery.

Aortic leaflets-- three semilunar fibrous cups at the exit of the left ventricular pumping chamber which seal higher pressures within the aorta during diastole while the left ventricle fills at lower pressure from the left atrium

AR-- aortic regurgitation

AS-- Aortic stenosis

ASH-- asymmetrical septal hypertrophy

Aortic valve-- the valve consisting of three semilunar leaflets located between the left ventricular outflow tract and the base of the aorta where lie the origins of the left and right coronary arteries. The three leaflets are cup-shaped toward the aorta, the aorta root, and prevent blood from flowing back into the left ventricle during diastolic relaxation of the left ventricular myocardium. The valve is open during left ventricular systolic ejection and normally produces no significant resistance to left ventricular outflow.

AP-- Antero-posterior(view); as in AP chest films.

Apex-- the cone-shaped end of the ventricular cavity most distant from the valves

Ascending aorta-- the ascending major vessel that acts as a conduit for the left ventricular pumping chamber distributing oxygenated blood to the body which extends to the aortic knob where the arteries to the head take off

Asymptomatic-- lack of awareness of dysfunction or pain.

Atelectasis-- Any degree of collapse or consolidation of the lung parenchyma, bronchi, or alveoli. Where lung parenchyma, alveoli, bronchi, and other normally air-filled spaces within the lung are shrunken and/or filled with fluid. May be chronic or acute and life--threatening and may be complete or partial in extent.

Atherosclerotic-- adj. Atherosclerosis--Abnormal condition in which fatty substances collect on the inner surfaces of the arteries, forming artherosclerotic plaques.

Atria-- The two thin-walled chambers of the heart that collect blood from the veins.

Atrioventricular groove-- the fibrous tissues in a plane encircling the base of the heart containing the mitral and tricuspid valves and dividing the atria from the ventricles

Atrioventricular node-- the electrical conductive tissue through which the depolarization wave from the sino-atrial node is conveyed to the ventricular myocardium. The node contains the bundle of His and is located near the inferior surface of the heart in a location identified as the crus

Atrium-- The thin-walled upper chambers of the heart that receive blood from the vena cava (right atrium), or oxygenated blood from the pulmonary veins from the lungs (left atrium).

Auscultation-- listening for sounds within the body;usually with a stethoscope.

Axial-- a view section which is perpendicular to the long axis of the body.

B

Bicusp-- bicuspid aortic valve

Bjork-- Bjork-Shiley tilting disk mechanical valve

Bronchial tree--the branching system of airways leading from the trachea to the microscopic ends of the respiratory system (the alveoli).

Bronchiectasis-- an abnormal and permanent enlargement of the diameter of the bronchi. This dilation of the bronchi may affect just one lung segment, or it may involve the whole bronchial tree.

Bronchioles-- the most distal airways whose walls contain cartilage, elastic fibers and smooth muscle

Bronchi-- the major larger air tubes to the lungs having cartilage in their walls and covered with a mucous membrane of columnar ciliated epithelial cells. The walls also contain smooth muscle.

Bronchogram-- This radiographic technique was achieved by dripping iodinated contrast material through a tiny catheter in the upper trachea passed through the vocal chords. The oily iodinated fluid coats the main bronchi and gives them a dense white appearance. Note that the carina lies at the bottom of the aortic knob and that the left main bronchus slopes more horizontally than the main right bronchus which is oriented mostly vertically. This radiographic technique has been largely replaced by magnetic resonance imaging (MRI).

Bronchus-- the main air tube to a lung having cartilage in its walls and covered with a mucous membrane of columnar ciliated epithelial cells.

Bullae-- (in lung imaging); abnormal blister-like cystic airspaces seen in diseased lung tissue, as in bullous emphysema. Bullae often enlarge as the disease progresses.

Bullous disease-- As in bullous emphysema; abnormal blister-like airspaces seen in diseased lung tissue. Bullae often enlarge as the disease progresses, and may compress more normal tissues and require surgical excision.

Bullous emphysema-- large cystic air collections in the lung with breakdown of normal parenchyma resulting in localized inability to oxygenate.

C

Calcification-- Process where generally abnormal deposits of localized calcium accumulate due to degenerative or pathologic processes.

Calcifications-- generally abnormal depositions of localized calcium due to degenerative or pathologic processes.

Carcinomas-- neoplastic tissues usually capable of metastasizing ("cancers").

Carcinomatous-- adj. neoplastic tissues usually capable of metastasizing ("cancers").

Carcinoma-- neoplastic tissues usually capable of metastasizing ("cancers").

Cardiac situs-- a description of the congenitally developed position of the heart relative to the thorax.

Cardiomegaly-- enlargement of the heart. When the term describes the heart on x-ray, it may be non-specific since the configuration can arise from fluid in the pericardium or enlargement of the chambers non-specifically.

Cardiomyopathy-- contractile dysfunction of the myocardium of the heart often leading to enlargement of the chambers.

Carina-- the ridge-like structure in the lumen of the trachea forming the inverted Y-shape where the trachea bifurcates into left and right bronchi.

Cathode ray tube-- an electronic display screen much like a television but dedicated to specific electronic purposes

Caudad-- adj.; toward the legs or feet.

Cavitation-- abnormal air spaces.

CB-- Conus branch; first branch of the right coronary artery.

Cephalad-- toward the head.

Cephalization-- in a direction toward the head of the body

Cervical ribs-- small, often incompletely formed rib(s) at the apex of the thorax originating from the last cervical vertebra. Normally there are only 12 ribs which originate from the thoracic vertebra.

Codominant-- a description of the coronary circulation in which both the right and left coronary arteries supply the myocardium of the inferior myocardial wall. This configuration is found in about 10% of the population

Coarctation-- localized narrowing, often of the aorta.

Collagen-- a tough, stringy protein that makes up most connective tissue in the vertebrate body.

Collaterals-- small side branches of a blood vessel, or other blood vessels that supply the same area.

Collimated-- narrowly limited to a thin beam

Compliant-- capable of easily expanding to accomodate incoming bloodflow, mostly characteristic of the venous, low pressure segment of the circulation

Computed tomography-- an imaging technique using accumulated patterns of received signals from multiple views around the object. The received patterns are accumulated and mathematically combined to estimate the internal structure of the original object.

Congenital-- present from birth; genetically inherited.

Consolidation-- a condensed mass of inflamed or fluid-filled lung tissue. A shrunken mass within the lung. Refers to either the mass itself or the process of formation.

Conus branch-- (CB); first branch of the right coronary artery.

Cooper's ligaments-- fibrous supporting tissues of the breast.

COPD-- chronic obstructive pulmonary disease.

Coronal-- vertically oriented section of the body in a direction as if facing the body en face.

Coronary arteries-- normally there are two coronary artery orifices approximately 3-4 mm in diameter originating from the aortic root just above the aortic valve in the sinus of Valsalva. The left main coronary artery is a short structure which immediately bifurcates into the left anterior descending [LAD] artery and circumflex [LCx]. The right coronary artery [RCA] proceeds along the atrio-ventricular groove on the right and descends toward the base of the heart.

Coronary ostea-- the opennings of the two major (right and left) coronary arteries

Coronary sinus-- the main vein draining the left ventricular myocardium. It receives flow from the great cardiac vein and conducts it in a channel along the left atrioventricular groove to drain into the right atrium.

Costal-- adj., pertaining to the ribs or ribcage.

Costophrenic angle-- (also called the costophrenic sulcus); the angle formed between the inner surface of the ribs and the dome of the diaphragm. As seen in posterior-anterior [PA] chest radiographs the costophrenic angles normally are seen in the lower left and right corners of the film, where the ribcage and lateral dome of the diaphragm meet.

Costophrenic angles-- (also called the costophrenic sulcus); the angle formed between the inner surface of the ribs and the dome of the diaphragm. As seen in posterior-anterior [PA] chest radiographs the costophrenic angles normally are seen in the lower left and right corners of the film, where the ribcage and lateral dome of the diaphragm meet.

Cranial-- adj., pertaining to the skull or head; as a direction, toward the head.

Crux-- junction of the left and right ventricles at the atrio-ventricular groove. The location is typically found on coronary angiography where a small perpendicularly-oriented vessel along the atrio-ventricular groove supplies the bundle of His.

CS-- coronary sinus

CT-- computed tomography; a technique for estimating the internal composition of a slice of an object by mathematical assessment of radiation patterns received external to the object; "CAT scans."

CW-- continuous wave

Cx-- circumflex coronary artery

D

D-- diagonal branch

DA-- descending aorta

Decubitus films-- films taken when the patient is lying on one side.

Decubitus-- (films) taken when the patient is lying on one side.

Delta-F (Ÿ)-- frequency shift

Delta-P (P)-- pressure gradient

Deoxygenated-- dark-appearing blood whose hemoglobin has given up its oxygen to the tissues

Desaturated-- dark-appearing blood whose hemoglobin has given up its oxygen to the tissues

Descending aorta-- the descending loop of thick-walled arterial major vessel distal to the left subclavian artery that acts as a conduit for the left ventricular pumping chamber distributing oxygenated blood to the lower body

Dextrocardia-- location of the heart in the right chest. This is not always an indicator of transposition, but in some cases there can be normal internal cardiac anatomy.

Diagonal artery-- small arteries that branch from the left anterior descending coronary artery supplying the anterior myocardial wall.

Diaphoresis-- especially profuse perspiration.

Diaphragm-- the sheet of smooth muscle separating the thorax from the abdominal contents which is cpapble of expanding the lungs in a bellow-like way

Diastole-- that portion of the cardiac cycle, usually occupying two-thirds of it, during which the ventricular myocardium relaxes and fills with blood from the low-pressure atria reservoirs

Diastolic-- adj.: that portion of the cardiac cycle, usually occupying two-thirds of it, during which the ventricular myocardium relaxes and fills with blood from the low-pressure atria reservoirs

Dipole-- a two-poled magnetic configuration implying a north and south orientation of its field

Distal-- adj., the area or direction farther away from the midline of the body, e.g.; "Your fingers are distal to your shoulders." See also, "proximal".

Diverticulae-- small balloon-like air collections, often from the gut.

Doppler-- shift in frequency of sound occurring when objects approach or travel away from the direction of the sound pulse travel. Precise measurement of the frequency shift permits estimation of the speed of the object motion.

Dx-- An abbreviation for the "diagonal coronary arteries" that branch from the left anterior descending coronary artery supplying the anterior myocardial wall.

Dyspnea-- shortness of breath; labored breathing.

Dysrythmias-- irregular electrical depolarization of the myocardium

E

ECG-- Electrocardiogram (sometimes, EKG). A recording of the electrical activity of the heart as it beats.

Echocardiographic-- ultrasound imaging of the heart

Echocardiography-- ultrasound method for imaging the heart, commonly combined with Doppler signal analysis to permit estimation and visualization of blood flow velocities within the vessels and chambers.

Ectatic-- dilated

ED-- end-diastolic

EDD-- end-diastolic dimension

Edematous-- adj. abnormal swelling of an organ due to the presence of fluid in the interstitial spaces of the tissue.

Edema-- abnormal swelling of an organ due to the presence of fluid in the interstitial spaces of the tissue.

EDV-- end-diastolic volume

EF-- ejection fraction

Effusion-- the abnormal escape of fluid from an organ into the surrounding body cavities.

EKG-- Electrocardiogram (usually, ECG). A recording of the electrical activity of the heart as it beats.

Electrocardiogram-- pattern of electrical depolarization that accompanies cardiac contractility.

Electromagnetic spectrum-- the range of wavelengths which describe transmissable electrical waves

Electromagnetic waves-- electric radiation emitted from an antenna by varying an electrical current

Emboli-- abnormal obstructions in the pulmonary blood vessels by clots, foreign matter, or air bubbles (gas embolism) in the bloodstream.

Embolus-- singular. abnormal obstructions in the pulmonary blood vessels by clots, foreign matter, or air bubbles (gas embolism) in the bloodstream.

Emphysema-- abnormal penetration of air into tissues.

End arterioles-- final branched segments of arterial vasculature with smooth muscle in its wall. In the heart because of its non-overlapping coronary branching structure, barring collaterals, most myocardial segments are fully dependent on single coronary vessels making ischemia a possibility

Endo-- endocardium, abbreviation

Endocarditis-- inflamation of the endocardium.

Endocardium-- the epithelium and connective tissue layer lining the inner chambers of the ventricles and atria of the heart.

Epi-- epicardium

Epicardium-- the outermost layer of the heart itself. Also called the visceral pericardium. The visceral pericardium is made up of thin connective tissues that bind and support capillaries and larger blood vessels of the coronary circulation, nerves, and a considerable amount of epicardial fat, particularly along the course of the larger coronary vessels.

Eponym-- a term which carries the name of its original describer

EPSS-- E-point septal separation (on M-mode)

ES-- end systole

ESD-- end systolic dimension

ERNA-- "Equilibrium Radionuclide Nuclear Angiogram"; a nuclear imaging technique in which radioactively labeled red blood cells emit radiation from the blood pool of the large vessels and chambers of the heart. By ECG time-gating, a dynamic change in the systolic-diastolic volume difference in the left ventricle can be measured which represents the left ventricle ejection fraction. Normally functioning left ventricles have an ejection fraction greater than 55%. Ejection fractions below 30% indicate severely depressed myocardial function from ischemia or cardiomyopathy.

Esophagus-- the smooth muscle tube connecting the mouth with the stomach

ESV-- end systolic volume

F

f-- frequency

Fibroadenoma-- benign neoplasm characterized by distinct and sharp boundaries. Although the tumor may grow locally, it is not known to metastasize or behave aggressively.

Fibrous dysplasias-- abnormal, non-calcified tissue in otherwise an anatomically bony structure.

Fissure-- narrow clefts separating the lobes of the lung; such as the horizontal and oblique fissures of the lung.

Fissures-- narrow clefts separating the lobes of the lung; such as the horizontal and oblique fissures of the lung.

Friedriech's Ataxia-- congentital disorder affecting the neural system resulting in a gait (walking) disorder and a global cardiomyopathy.

G

Gamma camera-- The generic term for nuclear medicine scintillation cameras that form two-dimenisonal images of radioactivly-labelled body organs by counting nuclear decay events.

Gamma rays-- high energy electromagnetic waves which arise from the nucleus of radioactive atoms when they decay

Gamma ray-- high energy (kilo to megavolts) penetrating radiation arising from the atomic nucleus when it undergoes a radioactive decay.

Gastroscope-- a small diameter flexible plastic-covered probe that can be inserted through the esophagus into the stomach

Gohn complex-- an eponym which describes an inflammatory nodule in the pulmonary apex with an accompanying hilar adenopathy in line with lymphatic drainage from that pulmonary segment. The complex is often characteristic of tuberculosis

Goiter-- abnormal swelling of the thyroid glandas a result of various causes.

Granulomas-- Tumors composed of granulation tissue.

Great vessels-- usually a description of the aorta and pulmonary artery. In the normal individual, the pulmonary artery is located anteriorly and slightly to the left of the aortic origin with the pulmonary valve located slightly superior to the aortic valve.

H

Habitus-- the shape or configuration of the body

Hemidiaphragm-- half (right or left) of the diaphragm; as seen in lateral chest films.

Hiatal hernia-- an invagination by part of the stomach up through the esophageal hiatus of the diaphragm and into the thoracic cavity.

Hilar nodes-- lymph nodes at the vascular root of the lung in the region of the major central pulmonary arteries and veins.

Hilar-- adj. pertaining to the hilum. The region on the medial surface of each lung where blood vessels and the primary bronchi enter the tissue of the lung. Also the area where the visceral pleura lining the surface of the lungs folds back and becomes the parietal pleura lining the mediastinum and inner walls of the thoracic cavity.

vHila-- singular: hilum. The regions on the medial surface of each lung where blood vessels and the primary bronchi enter the tissue of the lung. Also the area where the visceral pleura lining the surface of the lungs folds back and becomes the parietal pleura lining the mediastinum and inner walls of the thoracic cavity.

Hilum-- pl.: hila. The region on the medial surface of each lung where blood vessels and the primary bronchi enter the tissue of the lung. Also the area where the visceral pleura lining the surface of the lungs folds back and becomes the parietal pleura lining the mediastinum and inner walls of the thoracic cavity.

Hodgkin's-- a neoplasm of the lymph tissues.

HOCM-- hypertrophic obstructive cardiomyopathy

HPRF-- high pulse repetition frequency

Hypercholesterolemia-- elevated lipids in the bloodstream which are believed to predispose to progressive narrowing of arterial vessels, particularly the coronaries.

Hypertension-- arterial blood pressures which consistently exceed 150/90 mm Hg. during systole/diastole.

Hypertensive-- arterial blood pressures which consistently exceed 150/90 mm Hg. during systole/diastole.

Hypodense-- abnormally lacking in visual density as seen in diagnostic imaging; as in hypodense lung tissue.

I

IAS-- interatrial septum

Idiopathic-- of unknown cause; self-originated.

IHSS-- hypertrophic cardiomyopathy

INF-- inferior

Infarction-- (as in myocardial infarction). the deterioration or death of heart muscle as a result of poor blood supply. Usually due to blockage of the coronary arteries.

Inspiration-- precise term for inhaling air.

Interstitial edematous-- greater than normal extravascular fluid.

Interstitial-- adj. refers to the spaces within a tissue; such as the interstitial spaces within the lung parenchyma.

Interventricular groove-- (or interventricular sulcus). The groove that marks the divide between the muscular pumping chambers of the heart (the ventricles) from the thin-walled atria at the base of the heart. The groove encircles the heart, but is most prominent along the lateral walls and inferior surface of the heart. In that groove lie the tricuspid and mitral valves.

Interventricular septum-- the myocardium separating the left and right pumping ventricles. The interventricular septum is a muscular structure and may be up to 1.1 cm in thickness in normals. It tends to contract toward the left ventricle since that is the higher pressure chamber.

Ionizing radiation-- high energy radiation usually in the form of X-rays or gamma rays which interact with tissue by potentially ejecting electrons from atoms. The resulting ionization creates reactions which have the potential for adverse effect when physiologic repair mechanism fail.

Ischemia-- intermittent deprivation of oxygen carrying blood supply to contractile myocardium usually resulting in pain. Ischemia may be reversible, but when irreversible may result in infarction which leads to potential scar formation and lack of contractile function of segments of the heart.

Ischemic-- adj. intermittent deprivation of oxygen carrying blood supply to contractile myocardium usually resulting in pain. Ischemia may be reversible, but when irreversible may result in infarction which leads to potential scar formation and lack of contractile function of segments of the heart.

IVC-- inferior vena cava

IVCT-- isovolumic contraction time

IVRT-- isovolumic relaxation time

K

Kerley B lines-- horizontal straight lines visible on chest films, showing where the interlobar septa of the lungs have become abnormally swollen (edematous) or thickened in some pathologic process such as congestive heart failure, mitral stenosis, or other causes of lung edema.

Kilohertz-- a frequency of one-thousand cycles per second

L

LA-- left atrium; the heart chamber that receives oxygenated blood from the lungs via the pulmonary veins. The left atrium lies just posterior to the left ventricle, and is separated from the left ventricle by the mitral valve.

LAA-- left atrial appendage

LAD-- Left anterior descending artery; one of two major branches of the left coronary artery, [LCA]. The LAD branches from the LCA immediately after the origin of the LCA at the left base of the ascending aorta, and courses over the surface of the anterior heart directly over the muscular septum between the left and right ventricles. The LAD supplies oxygenated blood to the basal, anterior, septal, lateral, and apical portions of the left ventricular myocardium. The LAD generally wraps around the heart just to the right of the apex, and terminates just inferior to the apex of the left ventricle.

LAO-- left anterior oblique.

LAT-- lateral

LCA-- Left coronary artery.

LCC-- left coronary cusp

LCX-- left circumflex artery; one of the two major branches of the left main coronary artery, or LCA. The vessel courses along the atrio--ventricular (AV) groove and gives rise to one or several obtuse marginal (OM) vessels that supply the lateral wall of the left ventricle. In a minority of individuals the circumflex continues in the AV groove to supply the crux and give rise to a posterior descending artery (PDA)

Left anterior descending artery-- [LAD]; the major vessel arising from the left main coronary artery which lies anteriorly in the interventricular groove and provides perforator vessels into the anterior septum. The left anterior descending artery generally continues to the apex, commonly bifurcating into two short branches just before it ends (like a mermaidıs tail).

Left atrial appendage-- an extension of the left atrial cavity in a blind-ended triangular shaped-pouch slightly superior and anterior to the insertion of the pulmonary veins.

Left atrium-- the systemic atrium which collects oxygenated blood from the pulmonary veins and lies proximal to the mitral valve. The left atrium also includes a left atrial appendage which is triangular-shaped. The pericardium usually does not extend behind the left atrium and its lateral boundaries are delimited by the orifices of the several left and right major pulmonary veins.

Left circumflex coronary artery-- arises from the left main coronary artery at the bifurcation with the left anterior descending artery. The circumflex lies within the atrio-ventricular groove and supplies vessels to the lateral myocardium known as obtuse marginals. In patients with so-called "left dominate circulation", the circumflex supplies the inferior left ventricular wall by the posterior descending artery and the crux of the heart which is at the inferior junction of the mitral and tricuspid valves.

Left ventricle-- posteriorly located myocardial pumping chamber which receives oxygenated blood from the left atrium and pumps blood into the aorta at systemic pressures (generally, 120/80 mm. Hg.).

Left ventricular myocardium-- myocardium of approximately 10 mm thickness which contracts during systole to provide a left ventricular systolic pressure of approximately 120 mm of Hg.

Lingular-- adj. a portion of the medial anterior margin of the left lung, just below the cardiac notch of the left lung. Usually overlies the apex of the heart.

Lingula-- a portion of the medial anterior margin of the left lung, just below the cardiac notch of the left lung. Usually overlies the apex of the heart.

LMCA-- left main coronary artery

LPA-- left pulmonary artery

LSPV-- left superior pulmonary vein

Lucent foci-- areas of greater radiographic transparency (darker).

Lung parenchyma-- the dominant respiratory tissues of the lungs (as opposed to connective tissues, pleura, and other support structures within the lungs.)

LV-- Left ventricle; the myocardial boundary of the left ventricle is delimited by the vascular grooves occupied anteriorly by the left anterior descending (LAD) and inferiorly by the posterior descending arteries (PDA). Though most of the interventricular septum is committed to contraction of the left ventricular cavity, a millimeter or so of the right side of the septum supports right ventricular contraction.

LVH-- left ventricular hypertrophy

LVID-- left ventricular internal dimension

LVOT-- left ventricular outflow tract; the outflow tract is bounded inferiorly by the length of the anterior mitral leaflet and antero--superiorly by the interventricular and membranous septum.

Lymphadenopathy-- any disease of the lymphatic tissues, or lymph nodes.

Lymphomas-- a general term covering a number of malignant diseases of the lymphatic system and tissues.

Lymphoma-- A general term covering a number of malignant diseases of the lymphatic system and tissues.

M

Macroaggregated albumin-- serum albumin which has been aggregrated to particles in the range of a few hundred microns in diameter intended to allow them to disperse in the bloodstream when venously injected yet be completely trapped in their first pass into the distal pulmonary arterioles.

M-Mode-- motion display (depth vs time)

MAC-- mitral annular calcification

Main bronchi-- the thick-walled airways just distal to the bifurcation of the trachea at the carina.

Main bronchus-- the thick-walled airways just distal to the bifurcation of the trachea at the carina.

Malignancy-- having properties of invasion or metastasis; said of tumors; "cancers."

Malignant-- having properties of invasion or metastasis; said of tumors; "cancers."

Mammogram-- A radiograph (x-ray) of the breat (mammary galnd). Usually performed to detect potential breast tumors.

Marfan's disease-- a genetic disorder of the connective tissues which are characterized by hyperextensibility of the joints, a high arched palate, subluxation of the lens of the eye, redundant tissues of the mitral valve of the heart, aortic aneurysms, and a tall, lanky body.

Mastectomy-- surgical removal of the breast.

Mediastinal-- adj.; of the mediastinum. The organs and vessels lying between the sternum in the front and the spine posteriorly, and mid-way between the two lungs. The mediastinum contains the heart and major vessels as well as the trachea, esophagus, thymus, lymph nodes, and other structures.

Mediastinum-- the organs and vessels lying between the sternum in the front and the spine posteriorly, and mid-way between the two lungs. The mediastinum contains the heart and major vessels as well as the trachea, esophagus, thymus, lymph nodes, and other structures.

Megahertz-- a frequency of one-million cycles per second (implying very short wavelengths since frequency and wavelength are inversely related

Melanoma-- cancer of the melanotic cells of the skin

Membranous septum-- is a thin, relatively fibrous portion of the upper septum located just inferior to the aortic valve and is a common site of ventricular septal defects.

Membranous ventricular septum-- is a thin, relatively fibrous portion of the upper septum located just inferior to the aortic valve and is a common site of ventricular septal defects.

Metastases-- plural; spread of disease by lymphatic or blood-bourne cells from one organ or tissue to other organs within the body.

Metastasis-- singular; spread of disease by lymphatic or blood-bourne cells from one organ or tissue to other organs within the body.

Metastatic-- cancer cells which have spread by lymphatic or blood channels to distant tissues

Microcalcifications-- pinpoint calcifications commonly found in malignant tissues of the breast.

Mitral-- adj; of mitral valve. A large (4 square centimeter) surface valve lying in the left atrio-ventricular groove which opens during diastole to allow left ventricular filling by blood from the left atrium. Tips of the valve leaflets are attached by chordal structures to the two papillary muscles near the apex of the left ventricle which permit the valve to be competent during the high pressures achieved with left ventricular systole.

Mitral anulus-- the fibrous tissue at the base of the mitral valve leaflets. In the lateral posterior anulus region there lies the path of the left circumflex coronary artery and coronary sinus.

Mitral stenosis-- Narrowing and (usually) calcification of the opening of the mitral valve, that both restricts normal blood flow between the left atrium and left ventricle, and may also be associated with regurgitation leakage of blood back through the mitral valve into the left atrium. The classic X-ray finding for mitral stenosis is an enlarged left atrium, but mitral stenosis is usually best investigated by echocardiography which will show doming of the valve during diastole rather than full opening.

Mitral valve-- a large (4 square centimeter) surface valve lying in the left atrio-ventricular groove which opens during diastole to allow left ventricular filling by blood from the left atrium. Tips of the valve leaflets are attached by chordal structures to the two papillary muscles near the apex of the left ventricle which permit the valve to be competent during the high pressures achieved with left ventricular systole.

Mitral valve-- The two-leaved atrioventricular valve between the left atrium and left ventricle. Consists of a superior and inferior leaflet. Connected via the chordae tendineae to the anterior and posterior papillary muscles of the left ventricle.

MR-- mitral regurgitation

MRI-- magnetic resonance imaging; a method of imaging primarily the hydrogen content of tissues by immersing the body in a strong magnetic field and then altering the alignment of protons by a sequence of radiofrequency electromagnetic pulses.

MS-- mitral stenosis

MV-- mitral valve

MVA-- mitral valve area

Myocardial infarction-- ischemic injury to the myocardium due to obstruction of the coronary artery depriving that portion of the myocardium of oxygen needed for metabolism. Prolonged ischemia (3-6 hours) can result in permanent necrosis with subsequent scar formation or lysis.

Myocardial perfusion-- arterial blood supply to the contractile cardiac muscle

Myocardial-- adj.: cardiac muscle

Myocardium-- The muscular tissue of the right and left ventricles of the heart richly supplied with coronary blood vessels and nerve fibers.

N

NCC-- noncoronary cusp

O

Obtuse marginal-- branches (of the left circumflex artery). The obtuse marginal branches originate along the course left circumflex artery on the left lateral surface of the left ventricle.

Obtuse marginals-- branches (of the left circumflex artery). The obtuse marginal branches originate along the course left circumflex artery on the left lateral surface of the left ventricle.

Oligemic-- adj.: without blood supply

OM-- abbreviation for Obtuse Marginal coronary arteries. The obtuse marginal branches originate along the course of the left circumflex artery on the left lateral surface of the left ventricle.

Orthogonal-- at 90° angle to a given direction.

Orthopnea-- shortness of breath when lying flat.

Osmotic pressure-- the water-attracting force arising from the density of proteins and other blood-components in vessels

Osteomas-- dense calcific bony tissue, often within otherwise normal bone.

Osteosarcoma-- cancerous tissue with some bony components.

P

P-- pressure

PA-- Pulmonary artery; anteriorly the pulmonary artery and its outflow tract lie anterior and superior to the left ventricular outflow tract (LVOT) and aortic root. The "T--shaped" bifurcation of the main pulmonary artery results in the right branch lying within the arch of the ascending aorta. In the context of radiography, PA could mean "postero-anterior" as the direction of the X-ray beam through the patient (as opposed to LAT, meaning "lateral").

Papillary muscles-- the major papillary muscles in the left ventricle are two cones of myocardial tissue located anteriorly and posteriorly near the apex to which chordal structures attach to both leaflets of the mitral valve are anchored.

Parasternal-- adjacent to the bony sternum

Parenchymal-- the functional tissue of an organ.

Parenchyma-- The predominant tissue type within an organ (not including support and connective tissues); as in lung parenchyma.

Parietal pericardium-- The visceral pericardium (or epicardium) forms a thin membrane covering the surface of the heart. A the base of the heart the visceral pericardium folds outward to enclose the heart in a second, loose covering called the parietal pericardium. The thin space between the layers of the pericardium is called the pericardial cavity. It is normally filled with a thin fluid that lubricated the layers as the heart beats within the pericardium.

Parietal pleura-- portion of the pleura lining the walls of the thoracic cavity.

Parietal pleura-- The visceral pleura lies on the surface of the lungs. At the base of the lungs where blood vessels and bronchi enter (the hilar area) the visceral pleural folds back to form the parietal pleura that lines the inner walls of the thoracic cavity. The thin space between the two pleura layers is (pleural cavity) normally filled with a thin lubricating liquid that allows the lungs to slide freely within the chest during respiration.

PD-- Synonymous with PDA. Posterior descending coronary artery (not "patent ductus" in this context); this vessel supplies the diaphragmatic inferior border of the heart, and in most individuals arises from the distal right coronary artery ("right dominant coronary circulation"). In fewer individuals (40%) the PDA arises as a branch of the distal left circumflex ("left dominant circulation").

PDA-- Posterior descending artery (not "patent ductus arteriosus" in this context); this vessel supplies the diaphragmatic inferior border of the heart and in most individuals arises from the distal right coronary artery (when the patient has what is called "right dominant coronary circulation"). In fewer individuals (40% of the population) it arises as a branch of the distal left circumflex ("left dominant circulation").

PE-- pericardial effusion

Perfused-- the flow of fluid through vessels of specific organs.

Perfusion imaging-- medical imaging based on radioactive tracers that are distributed by arterial supply to tissue

Perfusion-- flow of nutrient fluids to tissues particularly by the blood supply.

Pericardial effusion-- fluid accumulating in the virtual lubricated space between the cardiac epicardium (the surface of the myocardium) and pericardium

Pericardium-- A double-layered membrane surrounding the heart and great vessels of the mediastinum. A visceral pericardium (or epicardium) forms a thin membrane covering the surface of the heart. At the base of the heart the visceral pericardium folds outward to enclose the heart in a second, loose covering called the parietal pericardium. The thin space between the layers of the pericardium is called the pericardial cavity. It is normally filled (~ 25 cc.) with a serous fluid that lubricates the layers as the heart beats within the pericardium.

Photomultiplier tubes-- electronic amplifiers of faint light pulses

PHT-- pressure half-time

PLAX-- parasternal long axis

Pleural cavity--The very thin space between the visceral pleura on the surface of the lung and the parietal pleura that lines the mediastinum and inner walls of the thoracic cavity. Filled with a thin serous liquid that lubricates the space.

Pleural effusion-- abnormal fluid collections in the pleural space between the lung parenchyma and the thoracic wall.

Pleural effusions-- abnormal fluid collections in the pleural space between the lung parenchyma and the thoracic wall.

Pleura-- A thin, double membrane overlying the lungs and lining the thoracic cavity. The visceral pleura lies on the surface of the lungs. At the base of the lungs where blood vessels and bronchi enter (the hilar area) the visceral pleural folds back to form the parietal pleura that lines the inner walls of the thoracic cavity. The thin space between the two pleura layers is normally filled with a thin lubricating liquid that allows the lungs to slide freely within the chest during respiration.

PM-- papillary muscle

PMVL-- posterior mitral valve leaflet

Pneumococcal pneumonia-- An acute inflamation of the lungs caused by pneumococcal bacteria (typically diplococcus pneumoniae).

Pneumonia-- Inflamation of the lungs, caused by infections (pneumococcal, bacterial, or viral pneumonias) various chronic cardiopulmonary conditions (secondary penumonias), or reaction to inhaled chemicals, food particles, foreign matter, or other physical matter (aspiration penumonias).

Pneumonic infiltrates-- inflammatory fluids filling pulmonary airspaces

Pneumothorax-- air in the pleural space adjacent to the lung which may cause compression or collapse of the lung parenchyma with resulting failure to adequately ventilate.

Pores of Kohn-- small passages at alveolar level that allow some lateral drift of aeration

POST-- posterior

Posterior descending artery-- [PDA]; the vessel lying in the myocardial interventricular groove inferiorly which supplies perforating septal vessels to the inferior septum. In "right dominant" individuals, the vessel is supplied by the right coronary artery, and in the less common "left dominant" individual, the vessel arises from the left circumflex.

PR-- pulmonic regurgitation

PRF-- pulse repetition frequency

Projection-- search-light, forward directed radiation

Proximal-- adj., Located near, or in the direction of the midline of the body, e.g., "Your shoulders are proximal to your fingertips." the opposite of "distal".

PS-- pulmonic stenosis

PTCA-- percutaneous translumenal coronary angioplasty; a method of expanding a coronary obstruction by passing an inflatable thin arteriographically-guided inflatable balloon into the site of the obstruction.

Pulmonary arteries-- the main pulmonary artery is relatively short and immediately branches into the left and right main pulmonary arteries. The right main pulmonary artery crosses beneath the arch of the aorta and further bifurcates into superior and inferior segments carrying unoxygenated blood to the pulmonary alveoli.

Pulmonary artery-- the main vessel connected to the right ventricular outflow tract which delivers de-oxygenated blood to the pulmonary alveoli

Pulmonary edema-- abnormal collection of fluid in the lung in both parenchymal tissue and air spaces.

Pulmonary emboli-- clots thrown to the pulmonary arteries which obstruct flow to portions of the lung parenchyma often causing chest pain and incomplete blood oxygenation.

Pulmonary embolus-- a clot in the venous system, particularly in the pelvic veins or legs, can form when there is nenous stasis. Clots thrown to the pulmonary arteries which obstruct flow to portions of the lung parenchyma often causing chest pain and incomplete blood oxygenation.

Pulmonary hypertension-- increased vascular resistance of the pulmonary arteries increase the internal pressure above the normal pulmonary artery pressure value of 30/10 mm. Hg.

Pulmonary lobes-- the lungs are generally divided into five lobes with three on the right and two on the left. They are named on the right: the upper, middle, and lower; and on the left: the upper and lower. The lingula consists of the most inferior portion of the upper left lobe.

Pulmonary trunk-- the single large artery exiting the right ventricle. It bifurcates into right and left pulmonary arteries. The broad base of the pulmonary trunk below the pulmonary valve is termed the conus arteriosus. The interior lumen of the conus arteriosus and upper right ventricle is called the right ventricular outflow tract (RVOT).

Pulmonary valve-- The valve between the right ventricle and the pulmonary trunk, consisting of three semilunar leaflets.

Pulmonary vasculature-- pulmonary vessels composing both the pulmonary arteries which convey unoxygenated blood to the pulmonary alveoli and the pulmonary veins which contain the oxygen saturated blood to the left atrium for pumping by the left ventricle to the systemic circulation. The pulmonary vasculature is most visible at the left and right pulmonary hila which represent their main and largest vessels.

PV-- pulmonary vein

PW-- pulsed-wave Doppler

R

RA-- right atrium; the collecting chamber filled by the vena cavae which contracts to assist filling of the right ventricle through the tricuspid valve.

Radioactive tracers-- radioactively tagged materials that lodge or are specifically attracted to individual tissues

Radiodensity-- the relative reduction in radiation intensity as a beam of radiation passes through tissue; this results in local differing exposure on the X ray film creating the pattern of dark and light that is called the radiographic image.

Radiograph-- A process image produced through x-ray (roentgenography) or gamma ray radiography.

Radiographic density-- the relative reduction in radiation intensity as a beam of radiation passes through tissue -- a portion of it due to Compton scattering of the beam, but other mechanisms include ionization reactions; this reduction in the beam intensity leaving the body results in local differing exposure on the X ray film creating the pattern of dark and light that is called the radiographic image.

RCA-- right coronary artery.

RCA-- right coronary artery; arising from the sinus of Valsalva anteriorly, the vessel courses along the right sided atrio--ventricular groove, often giving off small conus branches to the right ventricular outflow tract. In its mid--portion it supplies blood via the acute marginal branch to the right ventricular free wall. In most individuals the vessel continues in the atrio--ventricular groove to supply the crux (with a branch to the AV node) and a posterior descending artery to the left ventricular inferior wall myocardium.

RCC-- right coronary cusp

Real time-- image renewal rates greater that about 25 images per second that create an appearance of smooth motion of a moving object

Respiratory membrane-- the layers of squamous epithelium and microscopic capillaries lining of the inner walls of the lung alveoli. The surface where actual exchange of gasses occurs in the lungs.

Reticulonodular-- a description of a pulmonary parenchymal pattern that is a combination of lacelike tracery and small round nodules

Rheumatic disease-- a cardiac disorder creating Valvular disease, particularly mitral stenosis due to an immunologic response to a prior beta-streptococcal (often pharyngeal) infection

Right atrial appendage-- triangular pouch of the right atrium located anteriorly.

Right atrium-- the thin-walled muscular chamber which acts as a receiving vessel for collecting unoxygenated blood from the body via the inferior and superior vena cavas.

Right bundle branch block-- [RBBB] an ECG pattern characteristic of an abnormal conduction depolarization pattern of the ventricular myocardium.

Right coronary artery-- (RCA); arising from the sinus of Valsalva anteriorly, the vessel courses along the right sided atrio--ventricular groove, often giving off small conus branches to the right ventricular outflow tract. In its mid--portion it supplies blood via the acute marginal branch to the right ventricular free wall. In most individuals the vessel continues in the atrio--ventricular groove to supply the crux (with a branch to the AV node) and a posterior descending artery to the left ventricular inferior wall myocardium.

Right ventricle-- myocardial pumping chamber located anteriorly which receives unoxygenated blood from the right atrium and pumps it into the pulmonary artery for perfusion and oxygenation by the lungs.

Right ventricular myocardium-- the muscular wall along the anterior right ventricular free wall generally measuring 2-3 mm in thickness. During systolic contraction, the right ventricular pressure generally rises to 25 mm of Hg.

RLL-- right lower lobe

RML-- right middle lobe (of lung)

RPA-- right pulmonary artery

RSPV-- right superior pulmonary vein

RSV-- regurgitant stroke volume

RUL-- Right upper lobe (of lung).

vRV-- right ventricle; the main pumping chamber that supplies venous blood to the lungs. Its walls (2--3 mm thick) are thinner than the left ventricular myocardium because of the relatively lower vascular resistance of the pulmonary vessels and the lower pressures (25/10 mm Hg) needed to pump that circulatory bed.

RVH-- right ventricular hypertrophy

RVOT-- right ventricular outflow tract; the portion of the right ventricular myocardium consisting of portions of the right ventricular free wall and conal tissues below the pulmonary valve.

S

SAM-- systolic anterior motion

Sarcoidosis-- chronic inflammatory process of the lungs and lymphatic tissues characterized by non-caseating granulomas.

Sarcoid-- (sarcoidosis); in lungs, multiple benign non-caseating nodules within the lungs.

Saturated-- hemoglobin whose oxygen-carrying capacity is fully occupied

SC-- subcostal

Schmorl's nodules-- Protrusions of the soft central portion of the vertebral disk into the cancellous bone of the adjacent vertebral body.

Scintigraphy-- two dimensional image formed by a camera sensitive to radioactive emmisions from a radioisotope administered to the patient prior to imaging. The radioisotope is selectively taken up by particular organs or tissues, as in myocardial perfusion imaging, where uptake of of the radioisotope is proportional to blood flow.

Scintillation camera-- a device using a scintillation crystal attached to photo detectors which convert and count gamma ray emissions from a given structure.

Scintillation crystal-- a crystal (usually sodium iodide) which, when it absorbs a gamma ray emits a faint light pulse

Scintillation crystal-- crystalline material capable of emitting a pulse of light when it is struck by ionizing radiation such as gamma rays or x-rays.

Seminomatous-- adj.; alignant neoplasm of the testes; seminoma.

Septum-- the dividing structure between two chambers

Sestamibi-- Technetium-99m sestamibi-- Technetium-based imaging agent widely used in nuclear perfusion imaging of the myocardium.

Sound spectrum-- the range of wavelengths (or inversely the frequency) of a physical wave which is transmitted through matter as regions of compression and rarefaction

SPECT-- Single Proton Emission Computed Tomography. A nuclear imaging technique which produces tomographic views of the body by reconstructing the cross-section from multiple views.

SSN-- suprasternal notch

ST segment-- that portion of the ECG between the QRS depolarization and the lower amplitude T wave.

Stenosis-- abnormal constriction or partial blockage of a blood vessel or heart valve.

Sternum-- the longitudinal bone in the mid-anterior thoracic wall to which are connected the clavicles and cartilages of the upper ribs.

Stress images-- technique for examining the heartıs coronary flow reserve by imaging the patient during exercise activity or pharmacologic maneuvers intended to reveal areas of marginal coronary flow reserve caused by partially obstructed regions of the coronaries.

Strictures-- abnormal partial blockage or constriction of the lumen of a bronchi or blood vessel.

Subpulmonic-- below the pulmonary parenchyma but generally within the pleural space.

Subxiphoid-- the lowest portion of the sternum appearing as a triangular-shaped process at the lower junction of the anterior cartilages of the ribs in the epigastric region.

Superior vena cava-- the venous confluence of the upper body draining into the right atrium

Suprasternal notch-- the top concave surface of the vertical bone which articulates with the cartilages of the first seven ribs. Within the suprasternal notch, the anterior portion of the trachea can be palpated.

SV-- stroke volume or sample volume

SVC-- superior vena cava

Syncytium-- a multi-nucleate organization of protoplasm produced by merging cells.

Systole-- the actively contractile phase of the cardiac cycle, usually accounting for one-third of the time of the cycle

Systolic-- adj.: the actively contractile phase of the cardiac cycle

T

Tc 99m sestamibi-- radioactive compound distributed by arterial blood flow to the myocardium for cardiac imaging to assess potential ischemia.

Technetium 99m sestamibi-- Technetium-based imaging agent widely used in nuclear perfusion imaging of the myocardium.

Technetium-- a high atomic material which is specifically generated to provide rapid radioactive decay creating 140 keV gamma rays. The 99m (metastable) compound has a half life time decay rate of 8 hours.

TEE-- transesophageal echocardiography

Tesla-- a unit of magnetism defined as 10,000 Gauss (the earthıs field is about one-half a Gauss)

Thallium 201-- radioactive compound which is a potassium analog. When injected into the vascular circulation is selectively taken up by myocardium revealing the perfused segments of the heart.

Thallium-- a radioactive element of atomic weight 201 which is a potassium analog and therefore rapidly enters contractile viable myocardium

Thorax-- the portion of the body contained within the bony rib cage and its external muscles.

Thrombolysis-- dissolving of a clot.

Thrombolytic-- dissolving of a clot.

Thymomas-- tumors of the anterior mediastinum, originating in the thymus gland.

Tidal volume--The volume of air inspired and exhaled during normal, quiet respiration is about 500cc, and is termed the tidal volume. During forced inspiration a much greater amount of air may be inhaled, up to about 3000cc in an adult. This greater volume is termed the inspiratory reserve volume. During forced exhalation an adult can exhale about 1200cc more greater than normal tidal volume, and this is termed the expiratory reserve volume. Some air remains in the lung even after forced exhalation, and that is called the residual volume. During the deepest breath you can take the inspiratory reserve volume is combined with your normal tidal volume and the expiratory reserve volume to form a maximum or vital capacity for the lungs. The vital capacity is the most air a person can possibly inhale during forced inhalation.

Tomogram-- See tomographic, below.

Tomographic-- a slice or planar section. Tomographic imaging is advantageous since examination of thin slices do not contain confusing overlapping structures.

Topical-- applied to the epidermis, mucous membranes or skin

Tortuous-- serpentine

TR-- tricuspid regurgitation

Trabecular-- adj.; referring to trabeculae, fibers of connective tissue that support or divide other tissues.

Trachea-- the major airway in the midline between the larynx and the carina where it bifurcates into the left and right mainstem bronchi just below the aortic knob

Transducer-- a material or device employed to convert one form of energy to another. For example, piezo-electric crystals convert electrical energy to acoustic vibration and vice versa.

Transesophageal-- an ultrasound technique by which the acoustic transducer is mounted on a gastroscope and passed into the lower esophagus, placing it in very close contact to the posterior heart so as to provide very high resolution echocardiographic images.

Tricuspid-- adj. (tricuspid valve); large valve with three leaflets lying in the atrio-ventricular groove on the right side of the heart. The edges of the leaflets are attached by chordal structures to papillary muscles and open during diastole to fill the right ventricle with desaturated blood originating in the right atrium. The chordal attachments permit the large surface area of the valve to withstand the right ventricular pressures during systole without becoming incompetent.

Tricuspid valve-- large valve with three leaflets lying in the atrio-ventricular groove on the right side of the heart. The edges of the leaflets are attached by chordal structures to papillary muscles and open during diastole to fill the right ventricle with desaturated blood originating in the right atrium. The chordal attachments permit the large surface area of the valve to withstand the right ventricular pressures during systole without becoming incompetent.

TS-- tricuspid stenosis

TTE-- transthoracic echocardiography

Tuberculosis-- bacterial infection which is often indolent and may produce a caseating granuloma as the body attempts to control the infection.

TV-- tricuspid valve

U

Ultrasound-- acoustic vibration energy emitted by electrically polarizing a crystal (piezo-electric) which vibrates at a frequency of 1-7 MHz. The acoustic pulse travels through tissue, bouncing back small echoes at tissue interfaces which can be detected and timed to map tissue-structural distances using the same crystal (transducer) as a receiver.

V

V-- velocity

Valve leaflets-- the thin fibrous sails which act to confine and create differential pressures between two chambers or vessels. Valves guarantee a one-way flow of the circulation

Vascular-- the blood-containing channels

Vasculature-- vessels.

Veg-- vegetation

Ventricles-- The muscular pumping chambers of the heart, that by contraction force blood from the heart into the pulmonary artery (right ventricle) or aortic artery (left ventricle).

Ventricular apex-- the cone-shaped end of the ventricular cavity most distant from the valves

Ventricular ejection fraction-- the percentage of blood ejected by the cardiac ventricle during systole, normally a value greater than 55%.

Visceral pericardium-- The visceral pericardium (or epicardium) forms a thin membrane covering the surface of the heart. At the base of the heart the visceral pericardium folds outward to enclose the heart in a second, loose covering called the parietal pericardium. The thin space between the layers of the pericardium is called the pericardial cavity. It is normally filled with a serous fluid that lubricates the layers as the heart beats within the pericardium.

Visceral pleura-- The visceral pleura lies on the surface of the lungs. At the base of the lungs where blood vessels and bronchi enter (the hilar area) the visceral pleural folds back to form the parietal pleura that lines the inner walls of the thoracic cavity. The thin space between the two pleura layers is normally filled with a thin lubricating liquid that allows the lungs to slide freely within the chest during respiration.

Vmax-- maximum velocity

VSD-- ventricular septal defect

W

Westermark sign-- a blunt-ended major pulmonary vessel on x-ray with a paucity of distal vessels implying a large blocking clot within the artery

X

X ray-- high energy radiation (20-160 keV) generated by electron bombardment of a tungsten target. The directed energy, when used to illuminate the body will partially be transmitted and partially absorbed by dense body structures (especially bone) resulting in a relative "shadow-gram" when the exiting radiation is used to expose film.