Musculoskeletal Ultrasound — MCQs
Ultrasound is the investigation of choice for
Which of the following is the best in-vivo screening choice for carotid artery stenosis?
Which of the following is false with regards to ultrasonography?
Ultrasonic scalers vibrate at approximately what frequency?
Biphasic stridor is characteristically seen in:
Finkelstein's test is done for diagnosis of:
In which condition is the cleavage plane sign typically observed?
Which is not echogenic while doing ultrasonography:
Which of the following liver metastases appear hypoechoic on ultrasound?
Fallen fragment sign is a feature of what?
Musculoskeletal Ultrasound Indian Medical PG Practice Questions and MCQs
Question 1: Ultrasound is the investigation of choice for
- A. Somatostatinoma
- B. Intraductal Pancreatic calculi
- C. Urethral stricture
- D. Blunt abdominal trauma (Correct Answer)
Explanation: ***Blunt abdominal trauma*** - **Focused Assessment with Sonography for Trauma (FAST) exam** is the initial imaging modality of choice for rapidly detecting **intra-abdominal free fluid** (hemoperitoneum) in hemodynamically unstable patients with blunt abdominal trauma due to its speed, portability, and non-invasiveness. - It helps guide the need for further imaging or surgical intervention, making it critical in the acute setting. *Somatostatinoma* - Diagnosed primarily through biochemical tests (elevated **somatostatin levels**) and imaging like **CT, MRI, or somatostatin receptor scintigraphy (SRS)**, which are superior for localizing these rare neuroendocrine tumors. - Although ultrasound can sometimes detect pancreatic masses, it is not the **investigation of choice** for definitive diagnosis or staging of somatostatinomas. *Intraductal Pancreatic calculi* - Often best visualized with **Endoscopic Retrograde Cholangiopancreatography (ERCP)** or **Magnetic Resonance Cholangiopancreatography (MRCP)**, which provide detailed imaging of the pancreatic and bile ducts. - While transabdominal ultrasound can sometimes detect dilated ducts or large calculi, **Endoscopic Ultrasound (EUS)** is more sensitive and specific for intraductal pathologies, making routine transabdominal ultrasound not the primary choice. *Urethral stricture* - The gold standard for diagnosing urethral strictures is **urethrography** (retrograde urethrogram), which directly visualizes the stricture and its extent. - While ultrasound can sometimes be used to assess the urethra, it is less effective than urethrography for defining the length and severity of a stricture.
Question 2: Which of the following is the best in-vivo screening choice for carotid artery stenosis?
- A. Digital Subtraction Angiography (DSA)
- B. CT
- C. MRI
- D. USG (Correct Answer)
Explanation: ***USG*** - **Ultrasound** (USG), specifically **carotid duplex ultrasonography**, is the **safest**, most cost-effective, and readily available initial screening tool for carotid artery stenosis due to its non-invasive nature and ability to visualize blood flow and vessel morphology. - It combines **B-mode imaging** with **Doppler flow analysis** to provide real-time images and flow velocity measurements, allowing for assessment of the degree of **stenosis** and plaque characteristics without radiation or contrast agents. - Sensitivity and specificity exceed 85-90% for detecting significant stenosis, making it the preferred first-line screening modality. *Digital Subtraction Angiography (DSA)* - **DSA** is the **gold standard** for anatomical detail and remains the most accurate method for quantifying carotid stenosis, but it is **invasive** and requires arterial catheterization. - It involves **ionizing radiation** and **iodinated contrast agents**, carrying risks of stroke (0.5-1%), arterial dissection, nephrotoxicity, and contrast allergic reactions. - Due to its invasive nature and associated risks, DSA is reserved for **pre-surgical planning** or when non-invasive imaging is inconclusive, not for initial screening. *CT* - **Computed tomography angiography (CTA)** involves **ionizing radiation** and typically requires an **iodinated contrast agent**, which carries risks of allergy and nephrotoxicity. - Though CTA provides excellent anatomical detail and can visualize vessel wall calcification, it is generally reserved for confirmation or surgical planning rather than initial screening due to its higher cost, radiation exposure, and contrast-related risks. *MRI* - **Magnetic resonance angiography (MRA)** can visualize carotid arteries well but is more expensive, less accessible than ultrasound, and may require a **gadolinium-based contrast agent**, which can have adverse effects (nephrogenic systemic fibrosis in renal impairment). - It is often used when ultrasound findings are equivocal or in cases where CTA is contraindicated, but it's not the preferred initial screening method due to its complexity, cost, longer examination time, and contraindications (pacemakers, metallic implants).
Question 3: Which of the following is false with regards to ultrasonography?
- A. Interpretation only possible during the examination
- B. Inexpensive
- C. No radiation
- D. Not good for soft tissue (Correct Answer)
Explanation: ***Not good for soft tissue*** - This statement is **false** because ultrasonography is exceptionally good for imaging **soft tissues**, such as muscles, tendons, ligaments, and organs, providing detailed real-time visualization. - It excels in differentiating between solid and cystic structures and assessing blood flow within soft tissues. *Interpretation only possible during the examination* - This statement is **true** for many basic ultrasound examinations, where the dynamic nature of the scan often requires the sonographer or radiologist to interpret findings in **real-time**. - While images can be saved, the ability to manipulate the probe and observe structures in motion during the scan is crucial for a comprehensive diagnosis. *Inexpensive* - This statement is generally **true** when compared to other advanced imaging modalities like MRI or CT scans, making it a more **cost-effective** option for many diagnostic purposes. - The equipment and operational costs of ultrasound are lower, contributing to its affordability. *No radiation* - This statement is **true** as ultrasonography uses **sound waves** (high-frequency mechanical waves) rather than ionizing radiation, making it a safe imaging modality, especially for pregnant women and children. - The absence of radiation exposure is a significant advantage, allowing for repeated examinations without cumulative risk.
Question 4: Ultrasonic scalers vibrate at approximately what frequency?
- A. 25000 cycles per second (Correct Answer)
- B. 15000 cycles per second
- C. 10000 cycles per second
- D. 50000 cycles per second
Explanation: ***25000 cycles per second*** - This frequency, often expressed as 25-30 kHz (kilohertz), is the typical operating range for **ultrasonic scalers** like magnetostrictive and piezoelectric devices. - This high-frequency vibration creates **cavitation** and acoustic microstreaming effects, which are crucial for effective scaling and debridement. *15000 cycles per second* - While within the ultrasonic range (above audible sound), 15 kHz is generally considered a **lower frequency** for modern ultrasonic scalers, though some older models might operate at this frequency. - Scalers operating at this frequency might have slightly **reduced efficiency** compared to those in the 25-30 kHz range for calculus removal. *10000 cycles per second* - This frequency is generally **too low** for effective ultrasonic scaling. - Devices operating at this frequency would likely be less efficient in removing calculus and biofilm due to **insufficient vibratory energy**. *50000 cycles per second* - While technically ultrasonic, 50 kHz is a significantly **higher frequency** than typically used for dental scaling. - Operating at such high frequencies could potentially lead to **excessive heat generation** or be less effective for calculus removal, depending on the amplitude and power settings.
Question 5: Biphasic stridor is characteristically seen in:
- A. Bronchial foreign body
- B. None of the options
- C. Tracheal foreign body
- D. Laryngeal foreign body (Correct Answer)
Explanation: ***Laryngeal foreign body*** - **Biphasic stridor** is the hallmark finding in laryngeal/subglottic foreign bodies as they obstruct airflow during **both inspiration and expiration**. - The obstruction at the **glottic or subglottic level** causes turbulent airflow in both phases of respiration, producing the characteristic biphasic quality. - Often accompanied by **hoarseness**, **croupy cough**, **dysphagia**, and **respiratory distress**. *Tracheal foreign body* - Tracheal foreign bodies typically produce **expiratory stridor** or **monophonic wheeze** rather than biphasic stridor. - May present with **Holzknecht's sign** (slapping sound with respiration), **palpable thud**, and **audible slap**. - **Cough** and **dyspnea** are more prominent than stridor. *Bronchial foreign body* - Bronchial foreign bodies cause **wheezing**, **diminished breath sounds** on the affected side, and **obstructive emphysema**. - Located beyond the carina, they rarely cause stridor as stridor originates from **laryngotracheal** obstruction. - May present with **persistent cough**, **recurrent pneumonia**, or **atelectasis**. *None of the options* - This is incorrect as **laryngeal foreign body** is the classic cause of biphasic stridor in medical literature. - **Glottic and subglottic obstructions** characteristically produce biphasic stridor affecting both respiratory phases.
Question 6: Finkelstein's test is done for diagnosis of:
- A. Trigger finger (stenosing tenosynovitis)
- B. Acute compartment syndrome
- C. De quervain's tenosynovitis (Correct Answer)
- D. Carpal tunnel syndrome
Explanation: ***De Quervain's tenosynovitis*** - **Finkelstein's test** is the classic physical examination maneuver used to diagnose **De Quervain's tenosynovitis**. - The test involves pain elicited when the patient makes a **fist with the thumb tucked inside** the other fingers, and then ulnar deviates the wrist. *Trigger finger (stenosing tenosynovitis)* - While it is also a tenosynovitis, **trigger finger** affects the flexor tendons of the digits and is characterized by painful clicking or locking. - Diagnosis is clinical, based on observing the **finger catching or locking** during attempted extension. *Acute compartment syndrome* - This is a limb-threatening condition involving increased pressure within a muscle compartment, often due to trauma. - Diagnosis is based on **clinical signs** (pain out of proportion, pallor, paresthesia, pulselessness, paralysis) and **intracompartmental pressure measurements**. *Carpal tunnel syndrome* - This condition results from compression of the **median nerve** within the carpal tunnel, causing numbness, tingling, and weakness in the hand. - Diagnostic tests include **Tinel's sign** (tapping over the median nerve) and **Phalen's maneuver** (wrist flexion), not Finkelstein's test.
Question 7: In which condition is the cleavage plane sign typically observed?
- A. Parosteal osteosarcoma (Correct Answer)
- B. Ewing's sarcoma
- C. Chondrosarcoma
- D. Metastasis
Explanation: ***Parosteal osteosarcoma*** - The **cleavage plane sign** refers to the presence of a fat-filled or fibrous plane separating the tumor from the underlying cortex, which is characteristic of **parosteal osteosarcoma**. - This sign indicates the **juxtacortical (parosteal) growth pattern** of the tumor, which begins on the bone surface and typically grows outwards. *Ewing's sarcoma* - **Ewing's sarcoma** is a highly aggressive malignant bone tumor that originates in the bone marrow, often presenting with an **"onion-skin" periosteal reaction** due to its intramedullary growth. - It does not typically exhibit a clear cleavage plane between the tumor and the cortex as it grows from within the bone. *Chondrosarcoma* - **Chondrosarcoma** is a malignant tumor of cartilage, often showing **popcorn-like calcifications** and endosteal scalloping, indicating its cartilaginous matrix and intramedullary growth. - While it can be juxtacortical, it does not typically present with a distinct fat or fibrous cleavage plane from the underlying bone like parosteal osteosarcoma. *Metastasis* - **Bone metastases** are secondary cancers that have spread to the bone, often presenting as **lytic or blastic lesions** depending on the primary tumor type. - These lesions typically originate within the bone marrow and invade the bone structure, rather than growing from the surface with a distinct cleavage plane.
Question 8: Which is not echogenic while doing ultrasonography:
- A. Bile (Correct Answer)
- B. Bone
- C. Gas
- D. Gall stones
Explanation: ***Bile*** - Bile is largely composed of **water**, which allows ultrasound waves to pass through it with minimal reflection, appearing **anechoic** (black) on ultrasound. - This property makes the gallbladder lumen, when filled with bile, appear anechoic, which is crucial for identifying structures like gallstones. *Bone* - **Bone** is highly dense and reflects a significant portion of ultrasound waves, making it appear very **echogenic** (bright) on ultrasonography. - Due to its high reflectivity, bone often produces a strong **acoustic shadow** behind it, obscuring deeper structures. *Gas* - **Gas** (air) is a strong reflector of ultrasound waves and appears brightly echogenic, often with a characteristic **dirty shadowing** or **reverberation artifact**. - The presence of gas can significantly hinder visualization of underlying tissues due to its strong reflection and scatter of the ultrasound beam. *Gall stones* - **Gallstones** are solid concretions that are highly reflective of ultrasound waves, appearing as bright, **echogenic foci** within the gallbladder lumen. - A classic ultrasound sign of gallstones is an echogenic structure with strong **posterior acoustic shadowing**.
Question 9: Which of the following liver metastases appear hypoechoic on ultrasound?
- A. RCC
- B. Colon cancer
- C. Breast cancer (Correct Answer)
- D. Mucinous adenocarcinoma
Explanation: **Breast cancer** - Liver metastases from **breast cancer** frequently present as **hypoechoic lesions** on ultrasound, due to the tumor's cellular composition and vascularity. - This appearance helps differentiate them from other more commonly echogenic or mixed metastatic patterns. *RCC* - **Renal cell carcinoma (RCC)** metastases to the liver often appear **hyperechoic** or **mixed echogenicity** on ultrasound due to their rich vascularity. - This is a distinct characteristic, different from the predominantly hypoechoic nature seen with breast cancer metastases. *Colon cancer* - Liver metastases from **colon cancer** are typically **echogenic** or **mixed echogenicity** on ultrasound, sometimes with a hypoechoic rim ("target sign"). - Their presentation is generally not purely hypoechoic, making them distinguishable from breast cancer metastases. *Mucinous adenocarcinoma* - Liver metastases from **mucinous adenocarcinoma** can be quite variable, but they often appear **complex**, possibly with **cystic components** or mixed echogenicity, rather than uniformly hypoechoic. - The mucin content can create a distinct internal architecture on ultrasound that differs from solid hypoechoic lesions.
Question 10: Fallen fragment sign is a feature of what?
- A. Simple bone cyst (Correct Answer)
- B. Aneurysmal bone cyst
- C. Giant cell tumor
- D. Fibrous dysplasia
Explanation: ***Simple bone cyst*** - The **fallen fragment sign** is pathognomonic for a **simple bone cyst (SBC)**, occurring when a fragment of cortical bone breaks off and falls to the dependent portion of the cyst cavity. - This sign is visible on **radiographs** and indicates a **fluid-filled cavity**, as bone fragments would not fall in a solid tumor. *Aneurysmal bone cyst* - While also a **benign osteolytic lesion**, an aneurysmal bone cyst (ABC) is characterized by **blood-filled spaces** and does not typically exhibit the fallen fragment sign. - ABCs are often **expansile** and may show **fluid-fluid levels** on MRI, but not free-floating bone fragments. *Giant cell tumor* - This is an **aggressive, often benign** bone tumor characterized by **multinucleated giant cells** and typically affects the **epiphysis** of long bones in young adults. - Giant cell tumors are **solid lesions** and do not contain fluid-filled cavities where bone fragments could fall. *Fibrous dysplasia* - Fibrous dysplasia is a **developmental anomaly** where normal bone is replaced by **fibrous tissue and immature bone**. - Radiographically, it often presents with a **"ground-glass" appearance** and cortical thinning, but it is a solid lesion and does not feature the fallen fragment sign.
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