Digital Breast Tomosynthesis — MCQs
Which of the following statements are true? 1. Due to increasing mammography there occurs over diagnosis of breast carcinoma 2. Colon cancer screening is done by digital rectal examination 3. Oral cancer screening is done by visual inspection 4. Cervix cancer screening is done by a pap smear
Digital radiography differs from conventional in
Precise FNAC can be obtained by using:
What is not an advantage of USG over mammography?
Which of the following is the most sensitive investigation for ductal carcinoma in situ (DCIS) of the breast?
Gold standard investigation for breast carcinoma screening in a patient with silicone breast implants
For normal mammography, what is the nominal focal size of the X-ray tube used?
What is the typical radiation dose delivered during mammography?
Which of the following is NOT an indicator of malignancy on mammography?
Which of the following is NOT an indication of malignancy on mammography?
Digital Breast Tomosynthesis Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following statements are true? 1. Due to increasing mammography there occurs over diagnosis of breast carcinoma 2. Colon cancer screening is done by digital rectal examination 3. Oral cancer screening is done by visual inspection 4. Cervix cancer screening is done by a pap smear
- A. 1,2,3,4
- B. 4 only
- C. 1,3,4 (Correct Answer)
- D. 2,3,4
Explanation: ***Correct: 1,3,4*** - **Statement 1 is TRUE**: Overdiagnosis is a well-documented consequence of increased mammography screening. It detects slow-growing tumors that might never have caused clinical symptoms or harm during a woman's lifetime, leading to unnecessary treatment and associated morbidities. - **Statement 3 is TRUE**: Oral cancer screening primarily involves thorough visual inspection by a healthcare professional to identify suspicious lesions, ulcers, or color changes in the oral cavity. - **Statement 4 is TRUE**: Cervical cancer screening is effectively done by Pap smear, which detects precancerous and cancerous cells. - **Statement 2 is FALSE**: Digital rectal examination is NOT the primary screening method for colon cancer. Standard screening methods include colonoscopy, fecal occult blood testing (FOBT), and fecal immunochemical test (FIT). *Incorrect: 1,2,3,4* - While statements 1, 3, and 4 are true, statement 2 is incorrect. Digital rectal examination is not a primary or definitive screening method for colon cancer—it only examines the rectum and misses most of the colon. *Incorrect: 4 only* - While cervical cancer screening by Pap smear is true, this option is incomplete as it misses other true statements (1 and 3) regarding mammography overdiagnosis and oral cancer screening. *Incorrect: 2,3,4* - This option incorrectly includes statement 2. Colon cancer screening is NOT done by digital rectal examination. Proper screening methods include colonoscopy, FOBT, FIT, and flexible sigmoidoscopy.
Question 2: Digital radiography differs from conventional in
- A. X-rays are not required for imaging
- B. Images cannot be printed
- C. Radiation receptors are different (Correct Answer)
- D. Uses radiation other than X-rays
Explanation: ***Radiation receptors are different*** - Digital radiography uses **digital sensors** (e.g., CCD, CMOS, flat panel detectors) or **photostimulable phosphor plates** (PSP) to capture the X-ray image directly, unlike conventional radiography which uses film. - This fundamental difference in **receptor technology** allows for immediate image display, digital storage, and post-processing capabilities. *X-rays are not required for imaging* - Digital radiography is still a form of **X-ray imaging**; it uses X-rays to penetrate the body and create an image. - The difference lies in how these X-rays are **detected and processed**, not in their absence. *Images cannot be printed* - Digital images can be easily **printed** if desired, although they are primarily viewed and stored digitally. - The ability to print allows for physical copies, but the main advantage is digital storage and sharing. *Uses radiation other than X-rays* - Digital radiography exclusively uses **X-radiation** to generate images. - Techniques like MRI use radiofrequency waves and magnetic fields, and ultrasound uses sound waves; these are distinct modalities, not digital radiography.
Question 3: Precise FNAC can be obtained by using:
- A. CT
- B. MRI
- C. Endoscopic USG
- D. USG (Correct Answer)
Explanation: ***USG*** - **Ultrasound (USG)** guidance is the **most commonly used** modality for **fine needle aspiration cytology (FNAC)** due to its real-time imaging capabilities, allowing the operator to visualize the needle tip entering the lesion. - It is particularly useful for superficial lesions or those with a clear acoustic window, offering good **spatial resolution**, wide availability, no radiation exposure, and accessibility for most body regions. - USG provides excellent precision for routine FNAC procedures across various clinical settings. *CT* - **Computed tomography (CT)** provides excellent anatomical detail and is useful for guiding FNAC in deeper or more complex lesions within the body cavity (e.g., lungs, retroperitoneum). - However, it involves **ionizing radiation** and, unlike USG, does not offer real-time visualization of the needle path, requiring intermittent scanning. *MRI* - **Magnetic resonance imaging (MRI)** offers superior soft tissue contrast and is excellent for visualizing certain lesions, but it is less commonly used for routine FNAC guidance. - The high cost, long scan times, and challenges with MRI-compatible needles make it less practical for real-time guidance compared to USG or CT. *Endoscopic USG* - **Endoscopic ultrasound (EUS)** is highly effective for precise FNAC of lesions adjacent to the gastrointestinal tract (e.g., pancreas, mediastinum, submucosal lymph nodes) as it provides high-resolution imaging from within. - While very precise for its specific indications, it is an invasive procedure requiring endoscopy and is not suitable for all body regions like routine superficial or transthoracic biopsies where the question is generally referring to.
Question 4: What is not an advantage of USG over mammography?
- A. Can be used for guided biopsy
- B. Superior detection of microcalcifications (Correct Answer)
- C. In young females with dense breasts
- D. Can be used to differentiate solid VS cystic
Explanation: ***Superior detection of microcalcifications*** - **Mammography** is the gold standard for detecting **microcalcifications**, which can be a key indicator of **ductal carcinoma in situ (DCIS)** or early invasive breast cancer. - **Ultrasound (USG)** has limited sensitivity for detecting and characterizing microcalcifications. *Can be used for guided biopsy* - **USG-guided biopsy** is a common and advantageous technique for obtaining tissue samples from suspicious lesions in the breast or other organs. - This allows for **real-time visualization** of the needle, improving accuracy and reducing complications. *Can be used to differentiate solid VS cystic* - **USG** excels at distinguishing between **solid masses and fluid-filled cysts** due to differences in sound wave reflection. - This capability is crucial in characterizing breast lesions and often eliminates the need for further invasive procedures for benign cysts. *In young females with dense breasts* - **Dense breast tissue** in young females can obscure lesions on mammography, making interpretation difficult. - **USG** is particularly valuable in this population because it is not hindered by breast density and can provide a clearer view of underlying pathology.
Question 5: Which of the following is the most sensitive investigation for ductal carcinoma in situ (DCIS) of the breast?
- A. PET Scan
- B. Ultrasound
- C. Mammography (Correct Answer)
- D. MRI
Explanation: ***Mammography*** - **Mammography** is the **gold standard** and **primary imaging modality** for detecting **ductal carcinoma in situ (DCIS)**, primarily because it excels at visualizing **microcalcifications**, which are the hallmark of DCIS. - Approximately **80-90% of DCIS cases** present as **microcalcifications** on mammograms, making it the most important screening and diagnostic tool. - Mammography has **high sensitivity (85-95%)** for detecting DCIS, especially calcified forms, and is widely available and cost-effective. *MRI* - While **MRI** has high sensitivity for invasive breast cancer and can detect non-calcified DCIS, it is **not the primary screening tool** for DCIS detection. - MRI is typically used for **staging known DCIS**, evaluating **extent of disease**, detecting **additional foci**, and screening **high-risk patients**. - However, MRI has lower specificity and higher false-positive rates compared to mammography, limiting its use as a primary diagnostic tool. *PET Scan* - **PET scans** are generally **not sensitive** for detecting **DCIS** because DCIS lesions typically have a **low metabolic rate** and do not avidly take up the **FDG tracer**. - PET scans are primarily used for detecting **invasive cancers** and assessing **metastatic disease**, not for non-invasive lesions like DCIS. *Ultrasound* - **Ultrasound** has **limited sensitivity** for detecting **DCIS** because DCIS often does not present as a palpable mass or a distinct sonographic abnormality. - While ultrasound can be useful for evaluating palpable masses or guiding biopsies, it frequently **misses microcalcifications** that are characteristic of DCIS. - Ultrasound is mainly used as a **complementary tool** to mammography, not as a primary diagnostic modality for DCIS.
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: For normal mammography, what is the nominal focal size of the X-ray tube used?
- A. 0.2-0.25 mm
- B. 0.3-0.35 mm (Correct Answer)
- C. 0.4-0.45 mm
- D. 0.45-0.50 mm
Explanation: In mammography, high spatial resolution is critical for detecting tiny structures like microcalcifications. The focal spot size directly influences **geometric blurring** (penumbra); a smaller focal spot results in a sharper image. ### 1. Why Option B is Correct For **routine (normal) mammography**, a nominal focal spot size of **0.3 mm** (typically ranging from 0.3 to 0.35 mm) is the standard. This size provides an optimal balance: it is small enough to ensure high detail for screening while being large enough to withstand the heat generated by the X-ray tube during standard exposures without damaging the anode. ### 2. Why Other Options are Incorrect * **Option A (0.2-0.25 mm):** This is too large for magnification but smaller than the standard for routine screening. * **Options C & D (0.4-0.5 mm):** These sizes are used in general radiography (e.g., Chest X-rays, where focal spots are often 0.6–1.2 mm). In mammography, such large spots would cause excessive geometric blurring, making it impossible to see fine architectural distortions. ### 3. High-Yield Clinical Pearls for NEET-PG * **Magnification Mammography:** When a specific area needs to be magnified, a much smaller focal spot of **0.1 mm** (range 0.1–0.15 mm) is used to compensate for the increased blurring caused by the air gap. * **Anode Material:** Usually **Molybdenum (Mo)** or Rhodium (Rh) is used to produce low-energy (soft) X-rays (25–30 kVp) for better soft-tissue contrast. * **Orientation:** The cathode is placed over the **base of the breast** (chest wall) and the anode over the **apex** (nipple) to utilize the "Heel Effect" for uniform density.
Question 8: What is the typical radiation dose delivered during mammography?
- A. 0.1 Gray/study
- B. 0.01 centiGray/study
- C. 0.1 centiGray/study (Correct Answer)
- D. 0.01 Gray/study
Explanation: ### Explanation **1. Why Option C is Correct:** The radiation dose in mammography is measured as the **Mean Glandular Dose (MGD)**, which represents the average dose to the radiosensitive glandular tissue of the breast. For a standard two-view screening mammogram (per breast), the typical dose is approximately **1 to 2 mGy (0.1 to 0.2 rad)**. Since **1 rad = 1 centiGray (cGy)**, a dose of 0.1 rad is equivalent to **0.1 cGy**. This level of radiation is considered very low and is roughly equivalent to the amount of natural background radiation a person receives over seven weeks. **2. Why Other Options are Incorrect:** * **Option A (0.1 Gray):** This is equivalent to 100 mGy. This dose is far too high for diagnostic imaging and would be closer to levels used in therapeutic radiation or causing deterministic effects. * **Option B (0.01 cGy):** This is 0.1 mGy, which is too low to produce a diagnostic quality image of dense breast tissue. * **Option D (0.01 Gray):** This is equivalent to 10 mGy (1 rad). While some complex interventional procedures might reach this level, it is significantly higher than the standard dose for a screening mammogram. **3. High-Yield Clinical Pearls for NEET-PG:** * **Target/Filter Material:** Mammography uses low-energy X-rays (typically **25–35 kVp**) to maximize soft tissue contrast. Common target/filter combinations are **Molybdenum/Molybdenum** or **Rhodium**. * **MQSA Requirement:** The Mammography Quality Standards Act (MQSA) mandates that the dose should not exceed **3 mGy (0.3 cGy)** per view with a grid. * **Screening Guidelines:** In India, the general recommendation is annual or biennial screening starting at age 40–50 years. * **Risk vs. Benefit:** The risk of radiation-induced breast cancer is negligible compared to the benefit of early detection of spontaneous breast cancer.
Question 9: Which of the following is NOT an indicator of malignancy on mammography?
- A. Nodular calcification (Correct Answer)
- B. Speckled margin
- C. Attenuated architecture
- D. Irregular mass
Explanation: **Explanation:** In mammography, distinguishing between benign and malignant lesions depends on analyzing mass morphology, margins, and calcification patterns. **1. Why "Nodular Calcification" is the correct answer:** Nodular (or "popcorn-like") calcifications are typically large, coarse, and well-defined. These are classic features of **benign** lesions, most commonly seen in involuting **fibroadenomas**. Malignant calcifications, by contrast, are usually pleomorphic (variable shapes), fine-linear, or branching (casting), representing necrosis within ducts (e.g., DCIS). **2. Analysis of Incorrect Options (Indicators of Malignancy):** * **Speckled (Spiculated) Margin:** This is the most specific mammographic sign of malignancy. It represents the desmoplastic reaction of the surrounding tissue as the tumor invades. * **Attenuated (Distorted) Architecture:** Architectural distortion occurs when the normal radial septa of the breast are pulled or straightened. In the absence of a history of trauma or surgery, this is highly suspicious for invasive breast cancer. * **Irregular Mass:** Malignant tumors grow haphazardly, leading to an irregular shape rather than a smooth, round, or oval appearance (which favors benignity). **Clinical Pearls for NEET-PG:** * **BI-RADS Classification:** Used for standardized reporting. BI-RADS 5 indicates >95% risk of malignancy. * **Most common benign calcification:** Popcorn-like (Fibroadenoma). * **Most common malignant calcification:** Fine pleomorphic or fine-linear branching. * **Skin Changes:** Skin thickening (>2mm) and nipple retraction are secondary signs of malignancy. * **Screening:** Mammography is the gold standard for screening, but Ultrasound is the investigation of choice for women <35 years due to dense breast tissue.
Question 10: Which of the following is NOT an indication of malignancy on mammography?
- A. Nodular calcification (Correct Answer)
- B. Speckled margin
- C. Attenuated architecture
- D. Irregular mass
Explanation: ### Explanation In mammography, the primary goal is to differentiate between benign and malignant features based on mass morphology, margins, and calcification patterns. **1. Why "Nodular Calcification" is the correct answer:** Nodular (or "popcorn-like") calcifications are typically large, coarse, and well-defined. These are classic features of **benign** lesions, most commonly seen in **involuting fibroadenomas**. Malignant calcifications, by contrast, are usually pleomorphic, fine-linear, or branching (casting type), representing necrotic debris within ducts (as seen in DCIS). **2. Analysis of Incorrect Options (Malignant Features):** * **Speckled (Spiculated) Margin:** This is the most specific mammographic sign of malignancy. It represents the infiltration of cancer cells into surrounding tissue and the subsequent desmoplastic reaction. * **Attenuated (Distorted) Architecture:** Architectural distortion refers to the pulling or tethering of normal breast parenchyma without a visible central mass. While it can occur in post-surgical scars, in a screening context, it is highly suspicious for invasive lobular or ductal carcinoma. * **Irregular Mass:** Malignant tumors grow haphazardly, leading to an irregular shape. Benign lesions are more likely to be round, oval, or circumscribed. **3. High-Yield Clinical Pearls for NEET-PG:** * **BI-RADS Classification:** Used for standardized reporting. BI-RADS 4 and 5 indicate high suspicion of malignancy. * **Most specific sign of malignancy:** Spiculated margins. * **Benign Calcifications:** Popcorn (Fibroadenoma), Eggshell/Rim (Oil cysts), and Teardrop (Milk of calcium). * **Malignant Calcifications:** Fine pleomorphic or fine-linear branching (BI-RADS 5). * **Initial Investigation:** Mammography is the gold standard for screening women >40 years; Ultrasound is preferred for women <30 years or during pregnancy/lactation.
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