Cardiac MRI Techniques — MCQs
Investigation of choice for valvular heart disease-
Time of Flight technique is employed in —
Gadolinium is a contrast agent used for:
What is the investigation of choice for whole body imaging in metastatic breast cancer?
The most sensitive and practical technique for detection of myocardial ischemia in the perioperative period is -
MUGA scan is not useful in:
For pericardial calcifications, which is the best investigation?
Gold standard investigation for breast carcinoma screening in a patient with silicone breast implants
In aortic dissection, the most accurate investigation is:
In the condition shown below, rib notching is present in which of the following ribs? (AIIMS Nov 2015)
Cardiac MRI Techniques Indian Medical PG Practice Questions and MCQs
Question 1: Investigation of choice for valvular heart disease-
- A. Nuclear Cardiac imaging
- B. Precordial Doppler
- C. 2 D- Echocardiography (Correct Answer)
- D. MRI
Explanation: ***2 D- Echocardiography*** - **Transthoracic echocardiography (TTE)** is the initial and most common investigation for valvular heart disease due to its non-invasiveness, accessibility, and ability to visualize valve morphology and function in real-time [1]. - It provides critical information on valve structure, leaflet motion, chamber dimensions, ventricular function, and pressure gradients, allowing diagnosis and assessment of severity [2]. *Nuclear Cardiac imaging* - Primarily used for assessing **myocardial perfusion** and viability, rather than direct visualization of valve structure and function. - While it can indirectly assess the impact of valvular disease on ventricular function, it does not provide detailed information about the valves themselves. *Precordial Doppler* - **Doppler echocardiography** is a component of a full echocardiogram, used to quantify blood flow velocities and pressure gradients across valves [1]. - However, "precordial Doppler" is not a standalone comprehensive investigation for valvular disease; it must be combined with 2D imaging for a complete assessment. *MRI* - **Cardiac MRI (CMR)** offers excellent anatomical detail and precise quantification of ventricular volumes and function, and can assess valvular regurgitation. - It is often used as a complementary study in specific cases, particularly for complex congenital heart disease or when echocardiography is inconclusive, but it is not the primary or initial investigation due to cost and accessibility.
Question 2: Time of Flight technique is employed in —
- A. Spiral CT
- B. MR imaging (Correct Answer)
- C. Digital radiography
- D. CT angiography
Explanation: ***MR imaging*** - The **Time of Flight (TOF)** technique is a type of **magnetic resonance angiography (MRA)** that exploits the phenomenon of **flow-related enhancement** of fresh, unsaturated blood entering an imaging slice. - It is used to visualize blood flow without the need for an external contrast agent, making it particularly useful for assessing vessels in the brain and neck. *Spiral CT* - **Spiral CT** (helical CT) involves continuous data acquisition as the patient moves through the gantry, creating a spiral path of X-ray projection data. - While it has revolutionised CT angiography, it does not employ the Time of Flight principle, which is specific to MR imaging. *Digital radiography* - **Digital radiography** uses X-rays to create images, which are captured by digital sensors rather than photographic film. - This technique primarily focuses on structural imaging and does not involve the physical principles (like spin physics of protons in a magnetic field) necessary for Time of Flight applications. *CT angiography* - **CT angiography** uses **iodinated contrast material** injected intravenously to visualize blood vessels with high resolution using X-rays. - Unlike Time of Flight MRA, it relies on the contrast enhancement of flowing blood with an exogenous agent, not on the intrinsic properties of blood flow within a magnetic field.
Question 3: Gadolinium is a contrast agent used for:
- A. CT - angiography
- B. Bronchography
- C. MRI - Imaging (Correct Answer)
- D. Contrast Sonography
Explanation: ***MRI - Imaging*** - **Gadolinium** is a paramagnetic substance commonly used as a contrast agent in **Magnetic Resonance Imaging (MRI)**. - It works by altering the **T1 relaxation times** of protons in tissues, enhancing the signal and improving the visibility of certain structures or pathologies like **tumors** or **inflammation**. *CT - angiography* - **CT angiography** typically uses **iodine-based contrast agents**, not gadolinium, to visualize blood vessels. - Iodine contrast agents work by absorbing X-rays, making blood vessels appear bright on CT images. *Bronchography* - **Bronchography** is an older imaging technique that involved introducing an **iodinated contrast medium** directly into the bronchial tree. - It has largely been replaced by **high-resolution CT scans** for evaluating airways. *Contrast Sonography* - **Contrast-enhanced ultrasound (CEUS)**, or contrast sonography, primarily uses **microbubble contrast agents** made of inert gas. - These microbubbles enhance the reflectivity of blood, improving visualization of blood flow and organ perfusion.
Question 4: What is the investigation of choice for whole body imaging in metastatic breast cancer?
- A. Angiography
- B. Venography
- C. Magnetic Resonance Imaging
- D. CT Scan (Correct Answer)
Explanation: ***CT Scan (Correct answer for NEET 2013)*** - **Contrast-enhanced CT scan** was the standard imaging modality for **whole-body staging** in metastatic breast cancer at the time of this exam (2013). - CT offers **excellent spatial resolution** for detecting metastases in **bone, lung, liver, and lymph nodes**. - It is widely available, relatively quick, and provides comprehensive anatomical information. - **Modern Update:** While CT was the standard in 2013, **PET-CT (FDG-PET/CT) is now considered the gold standard** for whole-body staging in metastatic breast cancer due to its combined metabolic and anatomical imaging capabilities. However, PET-CT was not among the options in this historical question. *Magnetic Resonance Imaging* - **MRI** is highly sensitive for specific sites, particularly for **brain metastases** and **bone metastases (especially spine and bone marrow)**. - **Whole-body MRI** protocols are emerging but require longer acquisition times and specialized equipment. - Not ideal as a single first-line modality for comprehensive whole-body staging compared to CT (or modern PET-CT). *Angiography* - **Angiography** is an invasive vascular imaging procedure used to visualize **arterial blood flow**. - It has **no role in routine metastatic screening or staging** of breast cancer. - Reserved for specific indications like preoperative vascular mapping or interventional procedures. *Venography* - **Venography** specifically visualizes **venous structures** and is used to detect venous thrombosis or venous obstructions. - It is **not applicable** for detecting solid organ metastases, bone lesions, or lymph node involvement in cancer staging.
Question 5: 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 6: 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 7: For pericardial calcifications, which is the best investigation?
- A. Ultrasound
- B. CT scan (Correct Answer)
- C. MRI
- D. Transesophageal echocardiography
Explanation: ***Correct: CT scan*** - **CT scans** are highly sensitive and specific for detecting **pericardial calcifications** due to their excellent spatial resolution and ability to measure calcium density (Hounsfield units). - They provide detailed anatomical information about the **pericardium** and can accurately map the extent, location, and thickness of calcified areas. - **CT is the gold standard** for detecting and quantifying pericardial calcification, particularly in constrictive pericarditis. *Incorrect: Ultrasound* - While ultrasound (echocardiography) can visualize the pericardium and may detect calcifications, its ability to definitively identify and characterize **calcifications** is limited compared to CT. - **Acoustic shadowing** from calcifications can obscure underlying structures, making a precise assessment challenging. - Useful for detecting pericardial effusion and thickening, but not optimal for calcification assessment. *Incorrect: MRI* - **MRI excels** in visualizing soft tissues, pericardial inflammation, and fluid collections, but it is **poor at detecting calcium**. - Calcifications typically appear as signal voids (black) on MRI, making it difficult to differentiate them from other structures, air, or motion artifacts. - MRI is valuable for assessing pericardial inflammation and constriction but not the preferred method for calcification. *Incorrect: Transesophageal echocardiography* - TEE offers high-resolution images of cardiac structures and is primarily used for assessing valve function, intracardiac masses, endocarditis, and aortic pathology. - Its utility in detecting and characterizing **pericardial calcifications** is limited compared to CT, especially for diffuse or subtle calcifications. - The pericardium is not optimally visualized with TEE compared to transthoracic echocardiography.
Question 8: 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 9: In aortic dissection, the most accurate investigation is:
- A. MRI scan
- B. ECG
- C. Aortography
- D. CT scan (Correct Answer)
Explanation: ***CT scan*** - **CT angiography** of the chest is the **gold standard** and most accurate readily available imaging modality for diagnosing acute aortic dissection, with sensitivity and specificity both >95%. - It offers **rapid acquisition** (3-5 minutes), high spatial resolution, and is widely available in emergency settings. - It clearly visualizes the **true and false lumens**, intimal flap, entry/re-entry tears, extent of the dissection (Stanford/DeBakey classification), involvement of branch vessels, and any associated complications like pericardial effusion or mediastinal hematoma. *MRI scan* - **MRI/MRA** offers comparable diagnostic accuracy (sensitivity ~98%, specificity ~95%) without radiation exposure and is excellent for chronic dissections or surveillance. - However, its use in acute settings is limited by **longer acquisition times** (20-30 minutes), limited availability in emergency departments, and contraindications (pacemakers, metallic implants, claustrophobia). - It is **not feasible** in hemodynamically unstable patients requiring rapid diagnosis and intervention. *ECG* - An **ECG** is routinely performed to evaluate chest pain and rule out acute coronary syndrome, but it does **not visualize** the aorta or diagnose dissection. - It may show non-specific ST-T changes or signs of **myocardial ischemia** if coronary ostia are involved in the dissection, but these findings are neither sensitive nor specific for aortic dissection. *Aortography* - **Conventional aortography** (invasive catheter-based angiography) was historically the gold standard but has been **replaced by CT and MRI** as first-line imaging. - It has lower sensitivity (~85-90%) than modern cross-sectional imaging and carries procedural risks including **arterial access complications**, contrast-induced nephropathy, and stroke. - Currently reserved for cases where intervention is planned or when non-invasive imaging is inconclusive.
Question 10: In the condition shown below, rib notching is present in which of the following ribs? (AIIMS Nov 2015)
- A. 3rd to 9th ribs (Correct Answer)
- B. 1st to 9th ribs
- C. 11th and 12th ribs
- D. All ribs
Explanation: **3rd to 9th ribs** - The image provided depicts **coarctation of the aorta**, characterized by a narrowing of the aorta, typically distal to the origin of the left subclavian artery. - In coarctation of the aorta, collateral circulation develops through the **intercostal arteries** to bypass the constriction, leading to their enlargement and subsequent erosion of the inferior margins of the **3rd to 9th ribs**, a finding known as "rib notching." *1st to 9th ribs* - While rib notching affects upper ribs, it typically **spares the 1st and 2nd ribs** because the superior intercostal arteries (which supply these ribs) originate directly from the subclavian artery, often proximal to the coarctation, so they do not participate in collateral circulation as significantly. - The pattern of notching is usually more concentrated in the mid-thoracic region. *11th and 12th ribs* - Rib notching from coarctation of the aorta is rarely observed in the **floating ribs** (11th and 12th ribs). - These ribs have a different anatomical relationship with the pleura and typically do not bear the brunt of increased collateral flow from the intercostal arteries in the same way as the higher ribs. *All ribs* - Rib notching is a localized phenomenon reflecting increased blood flow through specific intercostal arteries involved in collateral circulation due to aortic coarctation. - Therefore, it does **not affect all ribs**, and its absence in certain ribs (like the 1st, 2nd, 11th, and 12th) helps differentiate this condition radiologically.
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