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🌬️ CHAPTER 5 — CARDIOVASCULAR SYSTEM
I. OVERVIEW OF THE CARDIOVASCULAR SYSTEM
The️ cardiovascular️ (CV)️ system️ delivers️ oxygen️ and️ nutrients️ to️ tissues️ and️ removes️ waste️ via️ a️ continuous,️ closed️ network️ of️ vessels. Two main subsystems:
- Pulmonary circulation: ️ right️ heart️ →️ lungs️ → ️left️ heart️ (gas️ exchange).
- Systemic circulation: ️ left️ heart️ →️ body️ →️ right️ heart️ (tissue️ perfusion).
II. ANATOMIC COMPONENTS
Heart Muscular,️ four-chambered️ organ️ in️ mediastinum. Right side: ️ low️ pressure,️ pumps️ deoxygenated️ blood️ →️ lungs. Left side: ️ high️ pressure,️ pumps️ oxygenated️ blood️ →️ body. Chamber Function Valves Right️ atrium Receives️ deoxygenated️ blood️ from️ SVC/IVC Tricuspid️ →️ right️ ventricle Right️ ventricle Pumps️ blood️ →️ lungs Pulmonic️ valve Left️ atrium Receives️ oxygenated️ blood️ from️ pulmonary️ veins Mitral️ valve Left️ ventricle Pumps️ blood️ →️ aorta/systemic Aortic️ valve Great Vessels Aorta: ️ main️ systemic️ artery️ (ascending,️ arch,️ descending). Pulmonary arteries: ️ to️ lungs. Vena cavae: ️ return️ blood️ to️ right️ atrium. Pulmonary veins: ️ carry️ oxygenated️ blood️ to️ left️ atrium.
III. CARDIAC CYCLE (PHYSIOLOGY)
The️ cardiac cycle ️ =️ one️ heartbeat️ (≈0.8️ s️ at️ 75 ️ bpm).
Phase Event Description Atrial systole. Atria️ contract. Push️ blood️ into️ ventricles. Ventricular systole. Ventricles️ contract. AV️ valves️ close️ (“lub”),️ semilunar️ valves️ open. Ventricular diastole. Ventricles️ relax. Semilunar️ valves️ close️ (“dub”),️ AV️ valves️ reopen,️ ventricles️ fill. Stroke Volume (SV): ️ amount️ ejected️ per️ beat️ (~70️ mL). Cardiac Output (CO): ️ SV️ ×️ HR️ (≈5️ L/min). IV. RADIOGRAPHIC ANATOMY OF THE HEART Normal chest X-ray appearance Taken️ PA️ erect️ at️ 72″️ SID. Heart size: ️ <️ 50%️ of️ thoracic️ width️ (Cardiothoracic️ ratio️ <️ 0.5). Right heart border: ️ right️ atrium. Left heart border: ️ left ️ventricle,️ aortic️ knob,️ and️ left️ atrial️ appendage. Common observations: Enlarged️ left️ atrium️ →️ double️ right️ heart️ border️ or️ splaying️ of️ carina. Left️ ventricle ️enlargement️ →️ downward,️ lateral️ cardiac️ apex. Right️ ventricle️ enlargement️ →️ filling️ of️ retrosternal️ space️ (on️ lateral️ view). V. IMAGING MODALITIES AND THEIR ROLES Modality Best for Examples Chest X-ray Size,️ shape,️ calcifications,️ congestion,️ cardiomegaly,️ pulmonary️ edema. Initial️ screening. Echocardiography (U/S) Valve️ function,️ chamber️ size,️ ejection️ fraction,️ congenital️ defects. Doppler️ echo️ shows️ flow️ direction. CT Angiography (CTA) Coronary️ arteries,️ aortic️ aneurysm/dissection,️ pulmonary️ embolism. Fast️ and️ detailed.
Condition Description & Pathophysiology Imaging Findings / Key Points pulmonary️ artery. Aortic Stenosis Narrow️ aortic️ valve/outflow. LV️ hypertrophy,️ post-stenotic️ dilation️ of️ ascending️ aorta.
VII. ACQUIRED CARDIOVASCULAR DISEASES
1. Atherosclerosis Most common vascular disease. Deposition️ of️ lipid plaques ️ (atheromas)️ in️ arterial️ walls️ →️ narrowing ️and️ reduced️ blood️ flow. Risk️ factors:️ age,️ hypertension,️ smoking,️ diabetes,️ hyperlipidemia. Complications: ️ ischemia,️ infarction,️ aneurysm,️ emboli. Imaging: ️ calcified️ plaques️ on️ CT;️ angiography️ shows️ stenosis.
Valve Affected Cause Imaging/Effect Aortic insufficiency Rheumatic,️ endocarditis LV️ dilation️ and️ cardiomegaly Echocardiography ️ is️ key️ diagnostic️ tool.
6. Pericardial Effusion Accumulation️ of️ fluid️ in️ pericardial️ sac. Causes: ️ infection,️ malignancy,️ trauma,️ post-MI,️ uremia. Radiograph: ️ “water-bottle”️ heart️ silhouette. Ultrasound: ️ confirms️ presence️ and️ volume️ of️ fluid. Large️ effusions️ →️ cardiac️ tamponade️ (emergency). 7. Aneurysm Localized dilation of an artery ️ due️ to️ wall️ weakening. Common ️sites: ️aorta️ (especially️ abdominal). Causes: ️ atherosclerosis,️ trauma,️ infection,️ connective️ tissue️ disorders. Imaging: o X-ray:️ curvilinear️ calcification. o CT/CTA:️ exact️ size,️ location,️ rupture️ risk. Treatment:️ surgical️ graft️ or️ stent. 8. Aortic Dissection Tear in the intima → blood enters wall, forming false lumen. Associated️ with️ hypertension,️ trauma,️ or️ Marfan️ syndrome. Symptoms: ️ sudden️ tearing️ chest️ pain️ radiating️ to️ back. Imaging: o CXR:️ widened️ mediastinum. o CTA/MRI:️ true️ vs.️ false️ lumen. Medical️ emergency️ —️ risk️ of️ rupture. 9. Pulmonary Embolism (PE) Embolus (clot) ️ from️ leg️ veins️ lodges️ in️ pulmonary️ arteries.
Symptoms: ️ dyspnea,️ chest️ pain,️ tachycardia,️ hemoptysis. Imaging: o CXR:️ often️ normal ️or️ wedge-shaped️ opacity️ (Hampton’s️ hump). o CT Pulmonary Angiography: ️ gold️ standard️ (filling️ defect). o NM V/Q scan: ️ mismatch️ between️ ventilation️ and️ perfusion. Treatment: ️ anticoagulants,️ thrombolytics.
10. Deep Vein Thrombosis (DVT) Formation️ of️ thrombus️ in️ deep️ veins️ (usually️ legs). Risk️ factors:️ immobilization,️ surgery,️ trauma,️ oral️ contraceptives. May️ cause️ PE ️ if️ dislodged. Diagnosis: ️ Doppler️ ultrasound,️ venography. VIII. RADIOGRAPHIC SIGNS OF COMMON CARDIOVASCULAR DISORDERS Sign / Term Description / Seen In Cardiomegaly Enlarged️ heart️ (>50%️ thoracic️ width)️ →️ CHF, ️pericardial️ effusion. Water-bottle heart Globular️ silhouette️ →️ pericardial️ effusion. Boot-shaped heart Upturned️ apex️ →️ Tetralogy️ of️ Fallot. Figure 3 sign Coarctation️ of️ aorta. Rib notching Collateral️ circulation️ (post-coarctation). Kerley B lines Pulmonary️ venous️ hypertension️ (CHF). Bat-wing pattern (^) Pulmonary️ edema. Egg-on-a-string Transposition️ of️ great️ arteries. Cephalization of vessels Pulmonary️ venous️ congestion️ (CHF). IX. KEY TECHNICAL CONSIDERATIONS Exposure adjustments: o Additive️ diseases️ (CHF,️ effusion,️ aortic️ aneurysm):️ ↑️ kVp. o Subtractive️ (emphysema):️ ↓️ kVp. Optimal projections:
REVIEW QUESTIONS
1. The heart chamber located most anteriorly and forming the anterior border of
the cardiacon a lateral chest radiograph is the:
a. Left atrium b. Left ventricle c. Right atrium d. Right ventricle.
Answer: d. Right ventricle Explanation:️ On️ the️ lateral chest radiograph ️ the️ right ventricle ️ forms️ the️ most️ anterior️ chamber️ and️ therefore️ the️ anterior️ border️ of️ the️ cardiac️ silhouette. The️ right atrium ️ lies️ posterior to the sternum - right heart border on PA ;️ the️ left️ chambers️ are️ more️ posterior/left. Radiographic ️relevance: ️ enlargement of the right ventricle ️ is ️seen ️as️ increased️ anterior cardiac bulge on lateral view ️ and️ increased retrosternal density ️ on️ the️ lateral️ projection. Causes️ include️ pulmonary️ hypertension,️ RV️ infarction,️ and️ chronic️ lung️ disease.
2. The bicuspid valve is also known as the:
a. Left atrioventricular valve b. Right atrioventricular valve c. Aortic valve d.
Pulmonary valve
Answer: a. Left atrioventricular valve
Explanation: The bicuspid valve is the same as the mitral valve, also called the left atrioventricular (AV) valve, because it sits between the left atrium and left ventricle. Function: prevents backflow from LV to LA during systole. Clinical/radiographic note: mitral stenosis → LA enlargement (double density on PA, posterior bulge on lateral); mitral regurgitation → LA and LV enlargement.
3. Contraction of the myocardium is termed:
a. Diastole b. Systole c. Peristole d. Myostole
Answer: b. Systole Explanation: Systole is the phase of the cardiac cycle when the myocardium (ventricles) contracts, ejecting blood into the pulmonary artery and aorta. Diastole is relaxation/filling. Clinical importance: many imaging measures (e.g., ejection fraction) use systolic function; echocardiography assesses systolic contraction.
4. How many posterior ribs should be visible on a good inspiration PA chest
radiograph?
a. 12 b. 10 c. 8 d. 6
Answer: b. 10 Explanation: On a properly performed PA chest radiograph with full inspiration, you should normally visualize about 10 posterior ribs above the diaphragm. This demonstrates adequate inspiratory effort (often used as a quality check). Fewer ribs suggests under-inspiration (may mimic consolidation), too many could be hyperinflation (COPD).
5. In a fetus, the ductus arteriosus connects the:
a. Aorta and the superior vena cava b. Aorta and pulmonary trunk c. Right and left
atria d. Right and left ventricles
Answer: b. Aorta and pulmonary trunk
Radiographic ️ features: ️ cardiomegaly, ️ pulmonary ️ vascular ️ congestion,️ interstitial/alveolar️ pulmonary️ edema️ (Kerley️ B️ lines,️ perihilar️ “bat-wing”️ pattern),️ possible️ pleural️ effusions. Common ️causes:️ ischemic️ heart️ disease,️ hypertension,️ valvular️ disease.
8.️ Risk️ factors️ associated️ with️ atherosclerosis️ include:️
A.️ Low️ blood️ sugar️ levels️ B.️ Hypertension️ C.️ Cigarette️ smoking️ a.️ A️ and️ B️ b.️ A️ and️
C️ c.️ B️ and️ C️ d.️ A,️ B,️ and️ C
Answer: c. B and C (Hypertension and Cigarette smoking) Explanation: ️ Major️ risk️ factors ️for ️ atherosclerosis ️ include ️ hypertension ️ and️ cigarette smoking ️ (also️ diabetes,️ hyperlipidemia,️ age,️ family️ history).️ Low️ blood️ sugar️ is️ not️ a️ risk️ factor. Pathophysiology:️ endothelial️ injury️ →️ fatty️ streaks️ →️ plaque️ →️ luminal️ narrowing️ and️ calcification. Imaging:️ calcified️ plaque️ may️ be️ visible️ on️ x-ray️ or️ CT;️ angiography️ demonstrates️ stenoses.
9.️ A️ decrease️ in️ tissue️ blood️ supply️ is️ termed:️
️️️️️️️️️️️️️️️️️️️️️️️️ a.️ Atheroma️ b.️ Infarction️ c.️ Ischemia️ d.️ Necrosis️
Answer: c. Ischemia Explanation: ️ Ischemia ️ =️ decreased️ blood️ supply ️to️ tissue,️ usually️ due️ to️ obstruction️ or️ narrowing️ of️ arteries️ (e.g.,️ coronary️ artery️ atherosclerosis). Infarction ️ is️ tissue️ death️ resulting️ from️ prolonged️ ischemia. Necrosis ️ is️ cell️ death️ (term️ to️ describe️ the️ result). Imaging: ️ischemia ️may ️not ️be ️visible ️on ️plain ️x-ray; ️functional ️imaging ️(stress ️test,️ nuclear ️perfusion, ️MRI) ️detects ️perfusion ️defects. ️Infarction ️can ️lead ️to ️wall ️motion️ abnormalities️ on️ echo,️ and️ later️ segmental️ thinning/scar️ on️ MRI.
10. The single most frequent cause of deaths in the United States is:
a. Congestive heart failure b. Coronary artery disease c. Transposition of the great
vessels d. Valvular disease
Answer: b. Coronary artery disease Explanation: ️ Coronary artery disease (CAD) ️ — ️ ischemic ️ heart ️ disease ️due ️ to️ atherosclerosis ️of️ coronary️ arteries️ —️ is️ the️ single️ most️ frequent️ cause️ of️ death️ in ️many️ countries️ (including️ the️ U.S.). Results️ in️ angina,️ myocardial️ infarction,️ heart️ failure,️ arrhythmias. Imaging:️ ECG/troponins️ diagnose️ acute️ MI;️ echocardiography️ shows️ wall ️motion️ abnormalities; ️ CT ️angiography ️and ️ invasive ️angiography ️ visualize ️ coronary️ stenoses.
11. Clinical signs of a myocardial infarction include:
A. Shortness of breath B. Crushing chest pain C. Neck pain a. A and B b. A and C c. B
and C d. A, B, and C
Answer: d. A, B, and C (Shortness of breath; Crushing chest pain; Neck pain) Explanation: ️ Myocardial infarction (MI) ️ commonly️ presents️ with️ crushing substernal chest pain ️ (often ️radiating ️to ️neck, ️jaw, ️left ️arm), ️ shortness of breath , ️diaphoresis,️ nausea,️ and️ sometimes️ neck️ or️ epigastric️ discomfort.️ All️ listed️ symptoms️ may️ be️ present. Clinical/radiographic: ️chest ️x-ray ️may ️be️ normal️ or ️show️ pulmonary️ edema ️if ️CHF️ develops; ️definitive ️diagnosis ️uses ️ECG ️changes ️and ️cardiac ️biomarkers. ️Prompt️ reperfusion️ therapy️ is️ crucial.
12. Which type of vessel is used as the graft material for coronary artery bypass
grafts?
a. Arteries b. Capillaries c. Veins
Answer: c. Veins Explanation: ️ Veins ,️ particularly️ the️ greater saphenous vein ,️ are️ commonly️ harvested️ for️ coronary artery bypass grafting (CABG) .️ The️ internal️ mammary ️ artery ️is️ also️ widely️ used ️(especially ️the ️left ️internal️ mammary ️artery ️to ️LAD) ️because ️arterial ️grafts ️have️ superior️ long-term️ patency,️ but️ historically️ and️ commonly️ vein grafts ️ are️ used.
Explanation: ️ Venous thrombosis ️ (DVT)️ most ️commonly️ affects️ the️ deep veins of the lower extremities ️ (popliteal,️ femoral, ️iliac ️veins). ️Risk️ factors️ include️ immobilization,️ surgery,️ malignancy,️ oral️ contraceptives,️ and️ hypercoagulable️ states. Clinical️ risk:️ DVT️ can️ embolize️ to️ the️ lungs️ causing️ pulmonary️ embolism. Imaging:️ Duplex Doppler ultrasound ️ is️ the️ primary️ diagnostic️ tool;️ venography️ is️ gold️ standard ️but️ invasive.
16.️ What️ common️ imaging️ procedures️ provide️ functional️ information️ regarding️ the️
heart?️
Key procedures that provide functional cardiac information:
- Echocardiography (transthoracic TTE and transesophageal TEE) o Provides️ real-time️ assessment️ of️ chamber sizes, wall motion, valve function ,️ ejection️ fraction,️ and️ pericardial️ effusion.️ Doppler️ assesses️ flow️ velocities️ and️ pressure️ gradients.️ First-line️ for️ most️ functional️ evaluations.
- Nuclear cardiac studies (SPECT, PET, MUGA) o Myocardial perfusion SPECT ️(stress/rest)️ assesses️ ischemia️ vs️ infarct️ (regional️ perfusion). o PET ️ assesses️ metabolic️ activity️ and️ viability. o MUGA (multigated acquisition) ️ evaluates️ left ventricular ejection fraction ️ and️ wall️ motion️ quantitatively.
- Cardiac MRI o Excellent️ for️ ventricular volumes, ejection fraction, myocardial viability/scar (late gadolinium enhancement) ,️ and️ tissue️ characterization️ (myocarditis️ vs️ infarct).️ Provides️ highly️ accurate️ functional️ measures.
- Nuclear ventriculography / radionuclide ventriculogram (MUGA) o Quantitative️ EF️ and️ wall️ motion.
- Stress testing with imaging ️ (exercise️ or ️pharmacologic️ stress️ +️ echo️ or️ nuclear) o Assesses️ inducible️ ischemia️ by️ comparing️ rest️ vs️ stress ️wall️ motion️ (stress️ echo)️ or️ perfusion️ (SPECT).
- Cardiac catheterization with ventriculography o Invasive️ but️ provides️ direct️ pressure️ measurements️ and️ can️ image️ LV️ function️ fluoroscopically.
Clinical note: ️ These️ modalities️ evaluate️ not️ just️ structure ️but️ dynamic️ function️ —️
critical️ in️ CAD,️ cardiomyopathy,️ valvular️ disease,️ and️ preoperative️ assessments.
17. Which type of aneurysm results when the intima tears and allows blood to flow within the vessel wall? Answer: Dissecting aneurysm (aortic dissection) Explanation: ️ A ️ dissecting aneurysm ️ (commonly️ called ️ aortic dissection )️ occurs ️when️ an️ intimal tear ️ permits️ blood️ to️ penetrate️ into️ the️ media️ and️ create️ a️ false lumen ️ between️ layers️ of️ the️ vessel️ wall.️ The️ dissection️ can️ propagate️ proximally️ or️ distally. Clinical ️presentation: ️sudden️ severe️ “tearing” ️chest/back ️pain,️ differences️ in ️limb️ blood️ pressure. Imaging:️ chest ️x-ray ️may️ show️ a️ widened mediastinum ;️ CT angiography ️ is ️the️ diagnostic️ study️ of️ choice️ to️ demonstrate️ true️ and️ false️ lumens️ and️ the️ intimal️ flap.️ Immediate️ medical/surgical️ management️ is ️needed.
18. An older adult has shortness of breath on exertion and overall respiratory
distress. The chest radiograph reveals an enlarged heart and a congested hilar
region, with some pul monary edema. What is the likely cause?
Answer: Left-sided congestive heart failure (likely due to ischemic heart disease or hypertensive heart disease) Explanation: The️ radiographic️ triad️ —️ cardiomegaly ,️ pulmonary vascular congestion (hilar congestion/cephalization) ,️ and ️ pulmonary edema ️ —️ is️ classic️ for️ left-sided heart failure .️ Common️ underlying️ causes️ include️ coronary artery disease (ischemic heart disease) ,️ long-standing️ hypertension ,️ or️ valvular️ disease. Pathophysiology:️ LV️ dysfunction️ →️ increased️ left️ atrial️ pressure️ →️ pulmonary️ venous️ hypertension️ →️ interstitial️ and️ alveolar️ edema. Clinical️ correlation:️ dyspnea️ on️ exertion,️ orthopnea,️ paroxysmal️ nocturnal️ dyspnea. Management:️ treat️ underlying️ cause,️ diuretics,️ afterload️ reduction,️ manage️ ischemia️ if ️present.
Q1.
Which️ radiographic️ sign️ is️ most️ characteristic️ of️ left ventricular hypertrophy (LVH)? A.️ Boot-shaped️ heart B.️ Globular️ heart C.️ Elongated️ left️ cardiac️ border D.️ Narrow️ mediastinum
🌬️ Answer: C. Elongated left cardiac border Deep Explanation: ️ LVH ️causes ️ prominence and elongation of the left ventricle ,️ leading️ to️ a️ downward and lateral displacement of the apex .️ This️ creates️ a️ bulging left cardiac contour ️ on️ PA️ chest️ radiograph. Boot-shaped️ heart️ →️ Tetralogy ️of️ Fallot. Globular️ heart️ →️ pericardial️ effusion. Q2. A ️ water-bottle shaped heart ️ on️ chest️ X-ray ️is️ most️ suggestive️ of: A.️ Dilated️ cardiomyopathy B.️ Pericardial️ effusion C.️ Aortic️ stenosis D.️ Pulmonary️ embolism 🌬️ Answer: B. Pericardial effusion Deep Explanation: ️ Large️ pericardial️ effusion️ produces️ a️ globular, symmetric enlargement ️ of ️the️ cardiac️ silhouette️ without️ pulmonary️ congestion. Important️ clue:️ rapid enlargement with clear lungs. Q3. Which️ condition️ produces️ a️ boot-shaped heart (coeur en sabot)? A.️ Mitral️ stenosis B.️ Tetralogy️ of️ Fallot C.️ Atrial️ septal️ defect D.️ Patent️ ductus️ arteriosus 🌬️ Answer: B. Tetralogy of Fallot Deep Explanation: ️ Due️ to️ right ventricular hypertrophy ,️ the️ apex️ is️ uplifted️ →️ boot shape .️ Also️ associated️ with️ decreased pulmonary vascularity. Q4. Double️ density️ sign️ on️ chest️ radiograph️ indicates:
