Functional Imaging in Cardiology — MCQs

10 questions

A 45-year-old man presents with intermittent pain in the chest, radiating to the left arm, aggravated by exertion, and relieved by rest. What is the most appropriate initial investigation?

99m Technetium labeled RBC scintigraphy is PRIMARILY used in the diagnosis of

The most sensitive and practical technique for detection of myocardial ischemia in the perioperative period is -

MUGA scan is not useful in:

Investigation of choice for DVT is -

Gold standard investigation for breast carcinoma screening in a patient with silicone breast implants

The most accurate investigation for assessing ventricular function is:

Which radioisotope is PRIMARILY used for detecting acute myocardial infarction rather than assessing myocardial perfusion?

Which finding on echocardiography suggests 'constrictive pericarditis'?

Q10

Investigation of choice for vascular ring around airway:

Functional Imaging in Cardiology Indian Medical PG Practice Questions and MCQs

Question 1: A 45-year-old man presents with intermittent pain in the chest, radiating to the left arm, aggravated by exertion, and relieved by rest. What is the most appropriate initial investigation?

A. Chest X-ray
B. Cardiac enzymes
C. ECG (Correct Answer)
D. Echocardiogram

Explanation: ***ECG*** - An **ECG** is the most appropriate initial investigation for suspected **angina pectoris** due to its rapid availability and ability to detect signs of **myocardial ischemia** or infarction [1]. - It can reveal changes such as **ST-segment depression** or elevation, **T-wave inversion**, or pathological Q waves [1]. *Chest X-ray* - A **chest X-ray** is useful for evaluating conditions like **pneumonia**, **pneumothorax**, or **heart failure** (cardiomegaly, pulmonary edema). - It is generally not the first-line diagnostic tool for **ischemic heart disease** as it cannot directly visualize coronary arteries or myocardial ischemia. *Cardiac enzymes* - **Cardiac enzymes** (e.g., troponin, CK-MB) are crucial for diagnosing **acute myocardial infarction** but are typically elevated hours after the onset of chest pain. - While important for confirming an MI, they are not the *initial* investigation for transient, exertion-related chest pain suggestive of **stable angina** [1]. *Echocardiogram* - An **echocardiogram** provides detailed information about **cardiac structure** and function, including **wall motion abnormalities**, valve function, and overall ejection fraction [1]. - While valuable, it is usually performed after an ECG to further evaluate the heart's pumping ability and identify **regional wall motion abnormalities** indicative of ischemia, rather than as the very first step [1].

Question 2: 99m Technetium labeled RBC scintigraphy is PRIMARILY used in the diagnosis of

A. Hepatoma
B. Left ventricular function wall motion
C. Hepatic hemangioma
D. GI Bleeding (Correct Answer)

Explanation: ***GI Bleeding*** - Technetium-99m labeled RBC scintigraphy (**99mTc-RBC scan**) is highly sensitive for detecting **active gastrointestinal bleeding**, especially slow or intermittent bleeding. - The labeled red blood cells extravasate at the site of bleeding, accumulating and outlining the bleeding focus over time. *Hepatoma* - **Hepatoma** (hepatocellular carcinoma) is primarily diagnosed using imaging modalities like **CT, MRI**, and **ultrasound**, often with contrast enhancement. - While nuclear medicine scans like **FDG-PET** can be used in some cases for staging or assessing viability, 99mTc-RBC scans are not a primary diagnostic tool for hepatoma. *Left ventricular function wall motion* - **Left ventricular function** and **wall motion abnormalities** are typically assessed using **echocardiography**, cardiac **MRI**, or **nuclear cardiology studies** like **SPECT** or **PET** using tracers that localize in the myocardium (e.g., 99mTc-Sestamibi or Thallium-201). - 99mTc-RBC scans are sometimes used for **gated blood pool scans** to assess global ejection fraction, but not directly for wall motion analysis in the same way as other dedicated cardiac modalities. *Hepatic hemangioma* - **Hepatic hemangiomas** can be characterized by **99mTc-RBC scintigraphy**, which shows **early photopenia** followed by **delayed fill-in and retention** of the tracer due to the characteristic slow blood flow within these benign vascular tumors. - While it can be used for confirmation, it's not the most commonly used primary diagnostic tool (which is often **ultrasound** or **MRI** with specific contrast patterns), and GI bleeding is a more direct application where the scan detects extravasation rather than vascular pooling.

Question 3: The most sensitive and practical technique for detection of myocardial ischemia in the perioperative period is -

A. Direct measurement of end diastolic pressure
B. Radio labeled lactate determination
C. Magnetic Resonance Spectroscopy
D. Regional wall motion abnormality detected with the help of 2D transoesophageal echocardiography (Correct Answer)

Explanation: ***Regional wall motion abnormality detected with the help of 2D transesophageal echocardiography*** - **Transesophageal echocardiography (TEE)** provides high-resolution images of the heart, allowing for the sensitive detection of **regional wall motion abnormalities (RWMA)**, an early and practical indicator of myocardial ischemia in the perioperative setting. - The development of new or worsening RWMA is often the **first sign of ischemia**, preceding ECG changes or hemodynamic alterations, making it a highly sensitive and clinically useful tool. *Direct measurement of end-diastolic pressure* - While an elevated **end-diastolic pressure** can indicate ventricular dysfunction, it is an **indirect sign** and not specific enough for early myocardial ischemia detection. - This measurement often requires invasive monitoring, which is less practical for routine detection compared to TEE. *Radio-labeled lactate determination* - **Lactate production** can increase in ischemic tissue, but its detection is a **biochemical marker** that typically lags behind the onset of ischemia. - This technique is generally **research-oriented** and not a practical, bedside method for rapid perioperative ischemia detection. *Magnetic Resonance Spectroscopy* - **Magnetic Resonance Spectroscopy (MRS)** can provide detailed metabolic information about tissue, including changes related to ischemia. - However, it is a **complex, time-consuming, and expensive imaging modality** that is not practical for routine, real-time perioperative monitoring of myocardial ischemia.

Question 4: MUGA scan is not useful in:

A. Stroke volume
B. Regional wall perfusion (Correct Answer)
C. Left ventricular ejection fraction
D. Regional wall motion

Explanation: ***Regional wall perfusion*** - A MUGA scan assesses **ventricular function** through blood pool imaging, evaluating wall motion and ejection fraction. - It does not directly visualize or quantify myocardial perfusion, which is the flow of blood through the coronary arteries to the heart muscle. *Stroke volume* - A MUGA scan accurately measures **end-diastolic volume** and **end-systolic volume**, from which stroke volume (EDV – ESV) can be calculated. - This parameter directly reflects the amount of blood pumped out by the ventricle with each beat. *Left ventricular ejection fraction* - The MUGA scan is considered a gold standard for calculating **left ventricular ejection fraction** (LVEF), a key indicator of cardiac pump function. - It uses a count-based method from gated blood pool images to determine the percentage of blood ejected from the left ventricle. *Regional wall motion* - MUGA scans are highly effective in assessing **regional wall motion abnormalities**, identifying areas of **hypokinesis**, **akinesis**, or **dyskinesis**. - This is crucial for diagnosing and monitoring conditions like myocardial ischemia or infarction, and is a primary utility of the scan.

Question 5: Investigation of choice for DVT is -

A. Doppler USG (Correct Answer)
B. MRI
C. CT scan
D. Angiography

Explanation: ***Doppler USG*** - **Doppler ultrasonography** is the **first-line investigation** for diagnosing deep vein thrombosis (DVT) due to its high sensitivity, specificity, and non-invasive nature. [1] - It visualizes venous flow, detects thrombus formation, and identifies **non-compressibility of veins**, which is a key diagnostic sign. *MRI* - While **magnetic resonance venography (MRV)** can detect DVT, it is generally reserved for cases where ultrasound is inconclusive or for imaging complex anatomical areas like the pelvic veins. - It is more expensive and less readily available as a primary diagnostic tool compared to Doppler USG. *CT scan* - **Computed tomography venography (CTV)** can visualize DVT, particularly in the pelvis and abdomen, but it involves **ionizing radiation** and requires intravenous contrast. [1] - It is not typically the first choice for DVT diagnosis in the extremities due to radiation exposure and the effectiveness of ultrasound. *Angiography* - **Conventional venography** (angiography) was once considered the gold standard for DVT diagnosis but is now rarely used due to its invasive nature, potential complications (e.g., contrast nephropathy, allergic reactions), and radiation exposure. [1] - It has largely been replaced by non-invasive imaging techniques like Doppler USG.

Question 6: Gold standard investigation for breast carcinoma screening in a patient with silicone breast implants

A. Mammography
B. CT scan
C. USG
D. MRI (Correct Answer)

Explanation: ***MRI*** - **MRI** is considered the **gold standard** for breast cancer screening in patients with silicone breast implants due to its superior ability to visualize breast tissue through the implant and detect subtle lesions. - It offers **high sensitivity** in detecting both implant rupture and early malignancies, often providing better clarity than mammography in augmented breasts where implants can obscure tissue. *Mammography* - While a standard screening tool, **mammography** can be limited in patients with silicone implants because the implants can **obscure adjacent breast tissue**, making detection of small masses challenging. - Special views (e.g., **Eklund views**) can be used, but sensitivity is still reduced compared to MRI in augmented breasts. *CT scan* - **CT scans** are not routinely used for primary breast cancer screening due to their use of **ionizing radiation** and lower sensitivity for detecting early breast lesions compared to MRI. - CT is more commonly used for **staging** advanced cancers or evaluating complex masses detected by other modalities. *USG* - **Ultrasound (USG)** is a valuable complementary tool, especially for evaluating palpable lumps or clarifying findings from mammography, but it is **operator-dependent** and has a lower overall sensitivity for general screening compared to MRI. - It is particularly useful for differentiating between **cystic and solid masses** and detecting implant ruptures but is not the gold standard for comprehensive screening in augmented breasts.

Question 7: The most accurate investigation for assessing ventricular function is:

A. Multislice CT
B. Echocardiography
C. MRI (Correct Answer)
D. Nuclear scan

Explanation: ***MRI*** - Cardiac MRI is considered the **gold standard** for assessing ventricular function, providing highly accurate and reproducible measurements of **ventricular volumes**, **ejection fraction**, and **myocardial mass**. - It offers excellent tissue characterization, allowing for direct visualization of **fibrosis**, **inflammation**, and other myocardial pathologies that can affect function. *Multislice CT* - While useful for assessing cardiac anatomy, particularly **coronary arteries**, Multislice CT involves **ionizing radiation** and has limitations in accurately assessing subtle changes in myocardial function compared to MRI. - Its strength lies more in **anatomical evaluation** (e.g., calcium scoring, coronary angiography) rather than detailed functional assessment. *Echocardiography* - Echocardiography is a widely available and useful first-line imaging modality for ventricular function, but it can be limited by **acoustic windows**, **operator dependency**, and **spatial resolution** compared to MRI. - While it provides good estimates of ejection fraction, particularly in simple cases, its 3D capabilities and tissue characterization are generally inferior to MRI. *Nuclear scan* - Nuclear scans (e.g., MUGA scans, SPECT) can assess ventricular function and myocardial perfusion, but they involve **ionizing radiation** and primarily provide **functional information** based on tracer uptake, not detailed structural or tissue characterization. - They are often used for evaluating **perfusion defects** and overall ejection fraction, but are less precise for detailed chamber quantification and tissue characterization than MRI.

Question 8: Which radioisotope is PRIMARILY used for detecting acute myocardial infarction rather than assessing myocardial perfusion?

A. Thallium 201
B. Tc-99m Sestamibi
C. Tc-99m Pyrophosphate (Correct Answer)
D. 18-FDG PET

Explanation: ***Tc-99m Pyrophosphate*** - This radioisotope binds to **calcium deposits** in infarcted myocardial tissue, which accumulate 12-24 hours after injury. - It is particularly useful for detecting **acute myocardial infarction** (hot spot imaging) when cardiac biomarkers may be unreliable or in cases of delayed presentation. - Shows positive uptake in necrotic tissue, making it a "positive" or "hot spot" agent for acute MI. *Thallium 201* - **Thallium 201** is a potassium analog that is actively transported into viable myocardial cells. - It is primarily used for assessing **myocardial perfusion** and viability, showing areas of reduced blood flow or scar tissue. - Acts as a "cold spot" agent - infarcted areas show reduced uptake. *Tc-99m Sestamibi* - **Tc-99m Sestamibi** is a commonly used tracer for **myocardial perfusion imaging (SPECT)**, indicating blood flow to the heart muscle. - It accumulates in viable myocardial cells in proportion to blood flow and is not specific for acute myocardial necrosis. - Used primarily for stress testing and perfusion assessment, not acute infarct detection. *18-FDG PET* - **18-FDG PET** (Fluorodeoxyglucose Positron Emission Tomography) primarily measures **glucose metabolism** in the myocardium. - It is predominantly used to assess **myocardial viability** in areas of hibernating myocardium rather than acute infarction. - Helps distinguish viable but ischemic tissue from scar tissue.

Question 9: Which finding on echocardiography suggests 'constrictive pericarditis'?

A. Pericardial thickening and septal bounce (Correct Answer)
B. Increased wall thickness
C. Global hypokinesis
D. Pericardial effusion

Explanation: ***Pericardial thickening and septal bounce*** - **Pericardial thickening** is a direct anatomical feature of constrictive pericarditis, indicating the fibrotic and inflamed state of the pericardium. - **Septal bounce**, or interventricular septal motion variation with respiration, is a highly specific sign of constriction, due to exaggerated ventricular interdependence. *Increased wall thickness* - This finding is more characteristic of **hypertrophic cardiomyopathy** or **hypertensive heart disease**, where the myocardial muscle itself thickens. - While it can impair diastolic function, it doesn't indicate a primary pericardial issue. *Global hypokinesis* - **Global hypokinesis** refers to reduced overall contractility of the heart muscle, typically seen in conditions like **dilated cardiomyopathy** or significant **ischemic heart disease**. - This indicates systolic dysfunction, whereas constrictive pericarditis primarily affects diastolic filling. *Pericardial effusion* - A **pericardial effusion** is an accumulation of fluid around the heart, which can cause **cardiac tamponade** if severe. - While effusions can sometimes precede or coexist with constrictive pericarditis, the fluid itself is not the hallmark of constriction, which is defined by a thickened, rigid pericardium.

Question 10: Investigation of choice for vascular ring around airway:

A. PET
B. Catheter directed angiography
C. MRI
D. CT (Correct Answer)

Explanation: ***CT*** - **CT angiography (CTA)** is the **investigation of choice** for diagnosing vascular rings due to its ability to provide detailed anatomical visualization of the great vessels and their relationship to the trachea and esophagus. - It offers high spatial resolution, allowing precise identification of the type of vascular anomaly, the degree of **airway and esophageal compression**, and guiding surgical planning. *PET* - **PET scans** are primarily used for assessing **metabolic activity**, particularly in oncology or to evaluate organ function, and do not provide sufficient anatomical detail for vascular rings. - While it can detect metabolically active lesions, it is **not suitable** for visualizing the structural abnormalities of blood vessels and their compressive effects on the airway. *Catheter directed angiography* - **Catheter-directed angiography** is an **invasive procedure** involving radiation and contrast, primarily used for assessing blood flow dynamics, identifying stenosis, or guiding interventions. - While it can visualize vessels, CTA is **less invasive**, provides comparable or superior anatomical detail for vascular rings, and is generally preferred for initial diagnosis. *MRI* - **MRI** can provide good soft tissue contrast and visualize vascular structures without radiation, but it is often **less readily available** and can be more challenging for pediatric patients due to the need for sedation and longer scan times. - For comprehensive anatomical detail including bone and calcifications, and in patients who might struggle with breath-holding, **CT angiography** often offers clearer and more consistent images of complex vascular anatomy.

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