Quantitative Imaging Biomarkers Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Quantitative Imaging Biomarkers. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Quantitative Imaging Biomarkers Indian Medical PG Question 1: N3a TNM staging of head and neck tumors (AJCC 8th edition) shows:
- A. Metastasis in a lymph node >6 cm (Correct Answer)
- B. Metastasis in lymph nodes >2 cm
- C. Metastasis in lymph nodes >5 cm
- D. None of the options
Quantitative Imaging Biomarkers Explanation: ***Metastasis in a lymph node >6 cm***
- **N3a disease** in head and neck cancer staging (AJCC 8th edition) specifically refers to metastasis in a single lymph node larger than 6 cm in greatest dimension **without extranodal extension (ENE)**.
- This applies to oral cavity, oropharynx (HPV-negative), hypopharynx, and larynx cancers.
- **Note:** N3 staging also includes **N3b** (metastasis in any node with clinically overt ENE), but this question specifically asks about N3a criteria.
*Metastasis in lymph nodes >2 cm*
- Lymph nodes in the 2-3 cm range typically fall within **N1 or N2a categories**, depending on laterality and number of involved nodes.
- **N3a disease** requires a single lymph node to exceed 6 cm in greatest dimension without ENE.
*Metastasis in lymph nodes >5 cm*
- A lymph node between 3-6 cm is usually classified as **N2 disease** (N2a if single ipsilateral ≤6 cm, N2b if multiple ipsilateral ≤6 cm, N2c if bilateral or contralateral ≤6 cm).
- To be classified as **N3a**, the lymph node must be **>6 cm** without extranodal extension.
*None of the options*
- This option is incorrect because the first option accurately describes the size criterion for **N3a TNM staging** in head and neck tumors according to AJCC 8th edition guidelines.
- While N3 staging has two subcategories (N3a and N3b), the size criterion of >6 cm correctly defines N3a disease.
Quantitative Imaging Biomarkers Indian Medical PG Question 2: If a biochemical test gives the same reading for a sample on repeated testing, it is inferred that the measurement is -
- A. Specific
- B. Accurate
- C. Sensitive
- D. Precise (Correct Answer)
Quantitative Imaging Biomarkers Explanation: ***Precise***
- **Precision** refers to the consistency or **reproducibility** of measurements. If repeated tests yield similar results, the measurement is considered precise.
- A precise test may not necessarily be accurate, but it consistently gives the same value, highlighting its **reliability** in producing repeatable results.
*Specific*
- **Specificity** refers to a test's ability to correctly identify individuals who do **not** have a particular condition (i.e., true negatives).
- It measures how well a test avoids **false positives**, indicating that a positive result is truly associated with the target analyte.
*Accurate*
- **Accuracy** refers to how close a measured value is to the true or **actual value**.
- A test is accurate if it provides results that are close to the correct value, not simply if they are consistently the same.
*Sensitive*
- **Sensitivity** refers to a test's ability to correctly identify individuals who **do** have a particular condition (i.e., true positives).
- It measures how well a test avoids **false negatives**, indicating that a negative result truly means the condition is absent.
Quantitative Imaging Biomarkers Indian Medical PG Question 3: Which imaging modality is most sensitive for detecting early ischemic stroke?
- A. Ultrasound
- B. PET scan
- C. CT
- D. MRI with DWI (Correct Answer)
Quantitative Imaging Biomarkers Explanation: ***MRI with DWI***
- **Diffusion-weighted imaging (DWI)** within an MRI scan is highly sensitive in detecting **cytotoxic edema** within minutes of **ischemic stroke** onset. This makes it crucial for early diagnosis and treatment decisions.
- DWI can identify areas of restricted water diffusion, which is a hallmark of acute cellular injury due to **ischemia**, even before changes are visible on conventional T1 or T2-weighted MRI sequences.
*CT*
- While frequently used in acute stroke settings, **non-contrast CT** is primarily used to **rule out hemorrhagic stroke** and may only show subtle or no signs of acute ischemia in the first few hours.
- Early ischemic changes on CT, often referred to as the **"ischemic penumbra"**, may appear hours after stroke onset, making it less sensitive for very early detection compared to DWI.
*Ultrasound*
- **Transcranial Doppler (TCD) ultrasound** can evaluate blood flow velocities in intracranial arteries and detect stenoses or occlusions but is not a primary imaging modality for directly visualizing brain parenchymal ischemia.
- Cervical ultrasound (e.g., **carotid duplex**) assesses extracranial vessels but cannot directly detect **ischemic changes** within the brain tissue itself.
*PET scan*
- **PET (Positron Emission Tomography)** can assess brain metabolism and blood flow but is typically not the preferred or most sensitive modality for **early detection of acute ischemic stroke** due to its complexity, cost, and limited availability in emergency settings.
- PET is more commonly used in research or for assessing chronic conditions and **metabolic abnormalities**, rather than acute stroke diagnosis.
Quantitative Imaging Biomarkers Indian Medical PG Question 4: Substance used for PET scan is
- A. Gadolinium
- B. Gastrografin
- C. Iodine
- D. 18F-FDG (Correct Answer)
Quantitative Imaging Biomarkers Explanation: ***18F-FDG***
- **18F-FDG (Fluorodeoxyglucose)** is a glucose analog labeled with a **positron-emitting radioisotope**, fluorine-18 (18F).
- It is the most commonly used radiotracer in PET scans, as it accumulates in cells with high metabolic activity, particularly **cancer cells** and activated brain cells.
*Gadolinium*
- **Gadolinium** is a paramagnetic contrast agent primarily used in **MRI scans** to enhance the visualization of blood vessels and abnormal tissues.
- It does not emit positrons and is therefore not suitable for PET imaging.
*Gastrografin*
- **Gastrografin** is an oral, water-soluble contrast agent containing **iodine**, typically used in **X-rays** and **CT scans** of the gastrointestinal tract.
- It is not a radioactive tracer and has no application in PET imaging.
*Iodine*
- **Iodine** in various forms can be used as a contrast agent in **X-rays** and **CT scans**, or as a radioactive isotope (e.g., **I-131**) for **thyroid imaging** and treatment.
- While some isotopes of iodine are radioactive, they are not typically used for PET imaging, which relies on positron emission.
Quantitative Imaging Biomarkers Indian Medical PG Question 5: MUGA scan is not useful in:
- A. Stroke volume
- B. Regional wall perfusion (Correct Answer)
- C. Left ventricular ejection fraction
- D. Regional wall motion
Quantitative Imaging Biomarkers 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.
Quantitative Imaging Biomarkers Indian Medical PG Question 6: A middle aged male patient presents with painless slow growing neck swelling. On examination, lymph nodes are positive. Surgery is done and biopsy is shown in the image below. Which of the following is false regarding the HPE findings?
- A. Spread is through lymphatics
- B. Nuclear features are the characteristic of this tumor
- C. FNAC is not diagnostic (Correct Answer)
- D. It has excellent prognosis
Quantitative Imaging Biomarkers Explanation: ***Fine needle aspiration cytology (FNAC) is not diagnostic***
- FNAC can often provide significant insights, but in cases of **specific malignancies** or certain lesions, it may not yield definitive diagnoses [1].
- Diagnostic challenges arise as **cellular architecture** or certain **nuclear features** may not be appreciated in FNAC samples [1].
*It spreads quickly via lymphatics*
- This condition can indeed spread via lymphatics, making it **aggressive** in nature [1].
- **Lymphatic spread** is a common pathway for many head and neck conditions, particularly malignancies [1].
*Excellent prognosis is associated with this condition*
- While some conditions may have favorable prognoses, many midline neck lesions can have **serious implications** depending on their nature [1].
- Prognosis often varies widely and may not always be classified as **excellent** based solely on initial presentation [1].
*Nuclear characteristics are used for the identification*
- Nuclear morphology is critical for identifying various **neoplastic conditions**, aiding in differentiation from benign lesions [1][2].
- Many pathologies, especially those involving **malignancy**, rely heavily on **nuclear features** for accurate diagnosis [1][2].
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1101-1102.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1100-1101.
Quantitative Imaging Biomarkers Indian Medical PG Question 7: A 48-year-old woman presents with suspected myocardial ischemia. Pharmacologic stress myocardial perfusion SPECT with Tc-99m sestamibi shows reversible perfusion defect in the inferior wall. Evaluate the optimal management approach based on this functional imaging finding.
- A. Reassure patient as findings represent artifact
- B. Start medical management without further investigation
- C. Recommend coronary angiography for further evaluation and potential revascularization (Correct Answer)
- D. Proceed directly to coronary artery bypass grafting
Quantitative Imaging Biomarkers Explanation: ***Recommend coronary angiography for further evaluation and potential revascularization***
- A **reversible perfusion defect** on SPECT denotes **stress-induced ischemia** with viable myocardium, characterized by reduced tracer uptake during stress that normalizes at rest.
- This finding indicates significant **coronary artery stenosis** (often >70%) and requires **coronary angiography** to define the anatomy and plan possible **percutaneous coronary intervention (PCI)**.
*Reassure patient as findings represent artifact*
- While **diaphragmatic attenuation** can cause inferior wall artifacts, a truly **reversible defect** (normal rest scan) is diagnostic of ischemia rather than a permanent artifact.
- Attenuation artifacts typically present as **fixed defects** or are clarified using **ECG-gated SPECT** to check for normal wall motion.
*Start medical management without further investigation*
- Although medical therapy is a pillar of CAD treatment, a documented **reversible defect** in a symptomatic patient warrants anatomical assessment to evaluate the risk of **major adverse cardiovascular events (MACE)**.
- Management solely with drugs is insufficient for patients with high-risk ischemia patterns on **functional imaging** who may benefit from revascularization.
*Proceed directly to coronary artery bypass grafting*
- **Coronary artery bypass grafting (CABG)** is a surgical intervention that requires prior visualization of coronary anatomy via angiography to determine the extent of disease (e.g., **triple-vessel** or **left main disease**).
- It is premature to provide surgical referral before confirming the **syntax score** or the suitability of the lesions for less invasive procedures like **angioplasty**.
Quantitative Imaging Biomarkers Indian Medical PG Question 8: A 70-year-old male with recurrent prostate cancer post-prostatectomy has rising PSA (4.2 ng/mL) but negative conventional imaging. Which functional imaging modality would provide the highest detection rate for disease localization in this clinical scenario?
- A. 68Ga-PSMA PET-CT (Correct Answer)
- B. In-111 Capromab pendetide scan
- C. 18F-FDG PET-CT
- D. Tc-99m MDP bone scan
Quantitative Imaging Biomarkers Explanation: ***68Ga-PSMA PET-CT***
- **68Ga-PSMA PET-CT** is currently the gold standard for detecting **biochemical recurrence** of prostate cancer, showing a detection rate of over 90% when PSA levels are >2 ng/mL.
- It targets the **Prostate-Specific Membrane Antigen**, which is significantly overexpressed in prostate cancer cells, allowing for precise localization of both local recurrence and **distant metastases**.
*In-111 Capromab pendetide scan*
- This older imaging modality (ProstaScint) targets an **intracellular epitope** of PSMA, which is less accessible in viable, non-necrotic cells compared to the extracellular targets of modern tracers.
- It has a much lower **sensitivity and specificity** compared to 68Ga-PSMA PET-CT and is rarely used in contemporary clinical practice.
*18F-FDG PET-CT*
- **18F-FDG** is generally not useful for prostate cancer because these tumors are typically slow-growing and have **low glucose metabolism** (low glycolytic rate).
- It is primarily reserved for **aggressive, high-grade**, or neuroendocrine-differentiated prostate cancers that have lost the ability to express PSMA.
*Tc-99m MDP bone scan*
- This is a conventional imaging modality that detects **osteoblastic activity** rather than the cancer cells themselves, often resulting in low sensitivity at low PSA levels.
- It is specifically limited to detecting **bone metastases** and cannot identify soft tissue recurrence or lymph node involvement in the pelvis.
Quantitative Imaging Biomarkers Indian Medical PG Question 9: A 58-year-old presents with progressive cognitive decline. MRI brain is unremarkable. FDG-PET shows bilateral temporoparietal and posterior cingulate hypometabolism with relative sparing of sensorimotor cortex. Analyze these findings to determine the most likely diagnosis.
- A. Normal pressure hydrocephalus
- B. Frontotemporal dementia
- C. Alzheimer's disease (Correct Answer)
- D. Vascular dementia
Quantitative Imaging Biomarkers Explanation: ***Alzheimer's disease***
- The classic FDG-PET findings for this condition involve bilateral **temporoparietal** and **posterior cingulate** hypometabolism while typically sparing the **sensorimotor cortex**.
- This metabolic signature often appears during the **prodromal phase**, frequently preceding the structural **atrophy** seen on traditional MRI scans.
*Normal pressure hydrocephalus*
- On imaging, this condition is characterized by **ventriculomegaly** disproportionate to the degree of cortical atrophy, which is not described here.
- Clinically, it presents with the classic triad of **gait disturbance**, **urinary incontinence**, and **dementia**, rather than isolated metabolic patterns on PET.
*Frontotemporal dementia*
- FDG-PET would typically demonstrate hypometabolism localized to the **frontal** and **anterior temporal lobes**, which differs from the posterior pattern seen in this case.
- Early symptoms usually include significant **personality changes** or **behavioral disturbances** rather than generalized progressive cognitive decline alone.
*Vascular dementia*
- PET scanning usually shows a **focal or multifocal** "patchy" pattern of hypometabolism corresponding to areas of prior **infarction** or chronic ischemia.
- Diagnosis is generally supported by MRI evidence of **lacunar infarcts**, **extensive white matter disease**, or territorial strokes.
Quantitative Imaging Biomarkers Indian Medical PG Question 10: A 62-year-old male with lung cancer undergoes baseline PET-CT showing a 4 cm right upper lobe mass with SUVmax of 8.5. After 2 cycles of chemotherapy, repeat PET-CT shows the mass measures 3.5 cm with SUVmax of 3.2. Analyze the metabolic response according to PERCIST criteria.
- A. Progressive metabolic disease
- B. Stable metabolic disease
- C. Partial metabolic response (Correct Answer)
- D. Complete metabolic response
Quantitative Imaging Biomarkers Explanation: ***Partial metabolic response***
- According to **PERCIST** criteria, a reduction in **SULpeak** or **SUVmax** of **≥30%** is classified as a partial metabolic response.
- In this case, the SUVmax decreased from **8.5 to 3.2**, which is a **62% reduction**, far exceeding the 30% threshold for response.
*Progressive metabolic disease*
- Defined by a **>30% increase** in SUVmax or the appearance of **new metabolic lesions**.
- This patient showed a significant decrease in metabolic activity, contradicting a diagnosis of progression.
*Stable metabolic disease*
- This category applies when the change in SUVmax falls between a **30% decrease and a 30% increase**.
- Since the metabolic activity dropped by 62%, the response is too significant to be labeled as stable.
*Complete metabolic response*
- Requires a total **disappearance of metabolic uptake** in all lesions, ideally dropping below the level of **background liver activity**.
- While the uptake decreased significantly, a residual **SUVmax of 3.2** indicates persistent metabolic activity, preventing a classification of complete response.
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