Ultrasound Machine Components and Controls — MCQs
What is an X-ray artifact?
Ultrasound is the investigation of choice for
Which of the following techniques uses piezoelectric crystals?
Which of the following investigations work on the same principle?
What is not an advantage of USG over mammography?
In current obstetrics practice, what is the best test for monitoring sensitized Rh negative mother?
If the central ray is perpendicular to the film but not to the object, then:
Focal and diffuse thickening of gallbladder wall with high amplitude reflections and 'comet tail' artifacts on USG suggest the diagnosis of –
A 26-year-old male presents to the outpatient department with a discrete thyroid swelling. On neck ultrasound, an isolated cystic swelling of the gland is seen. What is the risk of malignancy associated with this finding?
What is the gold standard diagnostic procedure for assessing placental location during the second trimester?
Ultrasound Machine Components and Controls Indian Medical PG Practice Questions and MCQs
Question 1: What is an X-ray artifact?
- A. A radiographic finding that indicates disease pathology
- B. A normal anatomical structure visible on X-ray
- C. An image distortion produced when the patient moves during the X-ray procedure
- D. An unwanted image distortion that doesn't represent actual anatomy (Correct Answer)
Explanation: ***An unwanted image distortion that doesn't represent actual anatomy*** - An **X-ray artifact** is any feature or distortion on a radiographic image that is not present in the actual object being imaged. - These can arise from various sources such as patient movement, equipment malfunction, or improper technique, leading to **misinterpretation** of the image. - Artifacts are unwanted findings that can obscure true pathology or mimic disease. *A normal anatomical structure visible on X-ray* - This describes a **true anatomical finding**, which is the intended purpose of an X-ray. - Normal anatomical structures are expected and assist in diagnosis, unlike artifacts which obscure or mimic pathology. *An image distortion produced when the patient moves during the X-ray procedure* - While **patient motion** is a common cause of X-ray artifacts, this describes just one specific type (motion artifact), not a comprehensive definition of what an artifact is. - Other sources like metallic objects, scatter radiation, or detector issues can also cause artifacts. *A radiographic finding that indicates disease pathology* - This describes **true pathology** or disease findings, which is what radiologists aim to identify. - Artifacts are the opposite - they are false findings that do not represent actual anatomy or pathology.
Question 2: 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 3: Which of the following techniques uses piezoelectric crystals?
- A. Ultrasonography (Correct Answer)
- B. NMR imaging
- C. X-ray diffraction
- D. Xeroradiography
Explanation: ***Ultrasonography*** - **Piezoelectric crystals** are the core component of **ultrasound transducers**, which generate and detect ultrasonic waves. - These crystals convert electrical energy into mechanical vibrations (sound waves) and vice-versa, allowing for the creation of images. *NMR imaging* - **NMR imaging** (Nuclear Magnetic Resonance, now commonly known as **MRI**) uses strong magnetic fields and **radiofrequency pulses** to generate images. - It relies on the magnetic properties of atomic nuclei, particularly hydrogen, rather than piezoelectric effects. *X-ray diffraction* - **X-ray diffraction** is a technique used to study the atomic and molecular structure of materials, and it involves the interaction of **X-rays** with the electron clouds of atoms. - It does not involve piezoelectric crystals; instead, it uses an X-ray source and a detector to measure diffracted X-rays. *Xeroradiography* - **Xeroradiography** is an older imaging technique that used **xerographic plates** coated with a photoconductive material (like selenium) to capture X-ray images. - It relies on electrostatic charges and dry development rather than piezoelectric crystals to produce images.
Question 4: Which of the following investigations work on the same principle?
- A. MRI and PET Scan
- B. CT and MRI
- C. CT and X-ray (Correct Answer)
- D. USG and HIDA Scan
Explanation: ***CT and X-ray*** - Both **Computed Tomography (CT)** and **X-ray** imaging utilize **ionizing radiation** to generate images of the body's internal structures. - They work by passing X-ray beams through the patient, with different tissues absorbing the radiation to varying degrees, which is then detected to create an image. *MRI and PET Scan* - **Magnetic Resonance Imaging (MRI)** uses **strong magnetic fields and radio waves** to create detailed images of soft tissues, based on water content. - **Positron Emission Tomography (PET) scans** use **radioactive tracers** to visualize metabolic activity and blood flow, detecting gamma rays emitted from the patient. *CT and MRI* - **CT scans** use **ionizing radiation** (X-rays) to produce cross-sectional images. - **MRI scans** use **magnetic fields and radio waves** and do not involve ionizing radiation. *USG and HIDA Scan* - **Ultrasound (USG)** uses **high-frequency sound waves** to create real-time images of organs and structures. - **Hepatobiliary Iminodiacetic Acid (HIDA) scans** are a type of nuclear medicine study that uses a **radioactive tracer** to evaluate liver and gallbladder function.
Question 5: 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 6: In current obstetrics practice, what is the best test for monitoring sensitized Rh negative mother?
- A. Biophysical profile
- B. Amniotic fluid spectrophotometry
- C. Middle cerebral artery Doppler wave forms (Correct Answer)
- D. Fetal blood sampling
Explanation: ***Middle cerebral artery Doppler wave forms*** - This is currently the most widely accepted and **non-invasive** method for monitoring **fetal anemia** in Rh-sensitized pregnancies. - An increase in the **peak systolic velocity (PSV)** in the middle cerebral artery indicates that the fetus is increasing cardiac output to compensate for a reduced oxygen-carrying capacity due to anemia. *Biophysical profile* - The biophysical profile assesses various fetal parameters like **movement**, **tone**, **breathing**, and **amniotic fluid volume**, which are often altered late in the course of severe fetal anemia. - It is a **less sensitive** indicator of early or moderate fetal anemia compared to MCA Doppler. *Amniotic fluid spectrophotometry* - This method measures the **bilirubin levels** in amniotic fluid, which correlates with the severity of hemolysis. - It is an **invasive procedure** (amniocentesis) and has largely been replaced by non-invasive MCA Doppler due to associated risks and better predictive value of Doppler. *Fetal blood sampling* - Fetal blood sampling (cordocentesis) provides a direct measurement of **fetal hemoglobin** and other blood parameters. - While definitive, it is a **highly invasive procedure** with significant risks, reserved primarily for confirmation of severe anemia or for direct transfusion, not for routine monitoring.
Question 7: If the central ray is perpendicular to the film but not to the object, then:
- A. Blurring of the image occurs
- B. Foreshortening of the image occurs (Correct Answer)
- C. Elongation of image occurs
- D. None of the options
Explanation: ***Foreshortening of the image occurs*** - When the **central ray** is perpendicular to the **film** but not to the **object**, the object appears shorter than its actual size because parts of the object closer to the film are projected at a relative angle that compresses the image. - This angular relationship causes the object's dimensions parallel to the central ray to be minimized on the film, leading to **foreshortening**. *Blurring of the image occurs* - **Blurring** typically results from patient movement, insufficient exposure time, or issues with the focal spot size, rather than the angulation between the central ray, object, and film. - While extreme angulation can degrade image quality, a specific blur due to perpendicularity to the film but not the object is less direct than geometric distortion. *Elongation of image occurs* - **Elongation** occurs when the **central ray** is perpendicular to the **object** but not to the **film**, causing parts of the object further from the central point of the beam to be stretched out. - In this scenario, the issue is the central ray being perpendicular to the film but not the object, which creates the opposite effect—foreshortening. *None of the options* - This option is incorrect because **foreshortening** is a distinct and predictable geometric distortion that occurs under the described conditions. - The specific angulation described directly leads to geometric distortion rather than an absence of effect.
Question 8: Focal and diffuse thickening of gallbladder wall with high amplitude reflections and 'comet tail' artifacts on USG suggest the diagnosis of –
- A. Carcinoma of gall bladder
- B. Adenomyomatosis (Correct Answer)
- C. Cholesterolosis
- D. Xanthogranulomatous cholecystitis
Explanation: ***Adenomyomatosis*** - This condition is characterized by **hyperplasia of the muscular layer** and **outpouchings of the mucosa** through the muscular wall (Rokitansky-Aschoff sinuses). - The thickened wall with **Rokitansky-Aschoff sinuses** containing bile or cholesterol crystals causes **high-amplitude reflections** and **comet tail artifacts** on ultrasound. *Carcinoma of gall bladder* - While carcinoma can also cause focal or diffuse thickening of the gallbladder wall, it typically appears as a **mass lesion** and **does not usually demonstrate comet-tail artifacts**. - **Comet-tail artifacts** are pathognomonic for **adenomyomatosis**, indicating gas, cholesterol crystals, or inspissated bile within Rokitansky-Aschoff sinuses. *Cholesterolosis* - This condition, also known as **strawberry gallbladder**, involves the deposition of **cholesterol esters in the lamina propria** of the gallbladder wall. - It usually presents as **multiple small polyps** on ultrasound, without the diffuse wall thickening or classic "comet tail" artifact seen with adenomyomatosis. *Xanthogranulomatous cholecystitis* - This is a rare, severe form of chronic cholecystitis characterized by **lipid-laden macrophages** and significant **fibrosis** in the gallbladder wall. - It causes **marked, diffuse mural thickening** or **nodular lesions** which can mimic carcinoma, but it typically **lacks the specific acoustic shadowing and comet tail artifacts** associated with adenomyomatosis.
Question 9: A 26-year-old male presents to the outpatient department with a discrete thyroid swelling. On neck ultrasound, an isolated cystic swelling of the gland is seen. What is the risk of malignancy associated with this finding?
- A. 48%
- B. 12%
- C. 24%
- D. 3% (Correct Answer)
Explanation: ***3%*** - **Purely cystic thyroid nodules** (as described in this case with "isolated cystic swelling") have a **very low risk of malignancy**, typically **2-3%** or less. - According to **ATA guidelines** and **TIRADS classification**, purely cystic nodules are considered **low suspicion** lesions. - The cystic nature suggests a **benign process** such as a degenerated adenoma, colloid cyst, or simple cyst. - **Fine needle aspiration (FNA)** may still be considered if the nodule is >2 cm or has any suspicious solid components, but is often not required for purely cystic lesions. *48%* - This percentage is **significantly higher** than the actual malignancy risk for a purely cystic thyroid swelling. - Such a **high risk** would typically be associated with **solid nodules** exhibiting highly suspicious ultrasound features such as: - Microcalcifications - Irregular or spiculated margins - Taller-than-wide shape - Marked hypoechogenicity - Extrathyroidal extension *24%* - This percentage represents a **moderate to high risk** of malignancy, which is **not characteristic** of an isolated purely cystic thyroid swelling. - A risk in this range might be seen with: - **Mixed solid-cystic nodules** with predominantly solid components - Solid nodules with **intermediate suspicious features** on ultrasound *12%* - While lower than 24% or 48%, 12% is still **considerably higher** than the generally accepted malignancy risk for purely cystic thyroid nodules. - This risk level could be plausible for: - **Predominantly cystic nodules** with some eccentric solid components - Solid nodules with **mildly suspicious** features on ultrasound
Question 10: What is the gold standard diagnostic procedure for assessing placental location during the second trimester?
- A. Transabdominal ultrasound imaging
- B. Transvaginal ultrasound imaging (Correct Answer)
- C. Computed Tomography (CT) scan
- D. Magnetic Resonance Imaging (MRI)
Explanation: ***Transvaginal ultrasound imaging*** - The **gold standard for accurate assessment** of placental location, particularly for determining the exact distance between the placental edge and the internal cervical os. - Provides **superior resolution and clarity** of the cervix and lower uterine segment compared to transabdominal approach, with sensitivity approaching **95-100%** for placenta previa diagnosis. - Particularly valuable when the placenta is **posterior**, in **obese patients**, or when transabdominal findings are equivocal. - **Safe procedure** with no increased risk of bleeding, contrary to historical concerns. *Transabdominal ultrasound imaging* - The standard **initial screening tool** for placental localization in routine second-trimester anatomy scans. - May provide **suboptimal visualization** of the lower uterine segment, especially with a posterior placenta, full bladder distortion, or maternal obesity. - Can **overestimate** the distance between placental edge and cervical os due to bladder compression effects, potentially leading to false-positive diagnoses of placenta previa that resolve on transvaginal imaging. *Computed Tomography (CT) scan* - Involves **ionizing radiation** exposure to the fetus, which is contraindicated in pregnancy except for emergent maternal indications. - Provides **poor soft tissue contrast** for placental assessment compared to ultrasound. - Not used for routine obstetric imaging. *Magnetic Resonance Imaging (MRI)* - Excellent soft tissue contrast but **more expensive**, time-consuming, and less readily available than ultrasound. - Reserved for **complex scenarios** such as suspected placenta accreta spectrum disorders, morbidly adherent placenta, or when ultrasound findings are inconclusive. - Not the primary modality for routine placental localization in the second trimester.
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