Imaging study selection principles US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Imaging study selection principles. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Imaging study selection principles US Medical PG Question 1: A 36-year-old male is taken to the emergency room after jumping from a building. Bilateral fractures to the femur were stabilized at the scene by emergency medical technicians. The patient is lucid upon questioning and his vitals are stable. Pain only at his hips was elicited. Cervical exam was not performed. What is the best imaging study for this patient?
- A. AP and lateral radiographs of hips
- B. Lateral radiograph (x-ray) of hips
- C. Magnetic resonance imaging (MRI) of hips, knees, lumbar, and cervical area
- D. Anterior-posterior (AP) and lateral radiographs of hips, knees, lumbar, and cervical area
- E. Computed tomography (CT) scan of cervical spine, hips, and lumbar area (Correct Answer)
Imaging study selection principles Explanation: ***Computed tomography (CT) scan of cervical spine, hips, and lumbar area***
- In **high-energy trauma** (fall from height), a CT scan is the **gold standard** for evaluating the **spine and pelvis**, providing detailed cross-sectional images superior to plain radiographs.
- Since the **cervical exam was not performed**, cervical spine imaging is **mandatory** per ATLS (Advanced Trauma Life Support) protocols. High-energy falls carry significant risk of **cervical spine injury** even without obvious neurological symptoms.
- CT allows comprehensive assessment of **hip fractures, pelvic injuries, and the entire spine** (cervical, thoracic, lumbar), identifying both obvious and **subtle fractures** that may be missed on plain films.
- This approach provides the most **efficient and thorough evaluation** in the acute trauma setting, allowing for appropriate surgical planning and ruling out life-threatening spinal instability.
*AP and lateral radiographs of hips*
- Plain radiographs provide **limited detail** and may **miss subtle fractures**, particularly in complex areas like the pelvis and acetabulum.
- This option **fails to address cervical spine clearance**, which is essential in all high-energy trauma patients, especially when cervical exam has not been performed.
- Radiographs are insufficient for **comprehensive trauma evaluation** after a fall from height.
*Lateral radiograph (x-ray) of hips*
- A single lateral view is **grossly insufficient** for evaluating hip and pelvic fractures, providing only a **two-dimensional perspective** that can miss significant injuries.
- This option **completely neglects spinal evaluation**, which is dangerous in an uncleared trauma patient with a high-energy mechanism.
*Magnetic resonance imaging (MRI) of hips, knees, lumbar, and cervical area*
- While MRI excels at evaluating **soft tissues, ligaments, and bone marrow**, it is **not the initial imaging modality** for acute bony trauma due to longer scan times and lower sensitivity for acute fractures compared to CT.
- MRI is **time-consuming and impractical** in the emergency setting for initial fracture assessment, potentially delaying definitive treatment.
- CT is superior for evaluating **acute skeletal injuries** in the trauma bay.
*Anterior-posterior (AP) and lateral radiographs of hips, knees, lumbar, and cervical area*
- Multiple plain radiographs have **limited sensitivity** for complex or non-displaced fractures, particularly in the **spine and pelvis**, making them inadequate for high-energy trauma evaluation.
- Obtaining multiple radiographic views requires **numerous patient repositionings**, which risks further injury if **spinal instability** is present.
- Plain films provide significantly **less diagnostic information** than CT scanning for trauma assessment.
Imaging study selection principles US Medical PG Question 2: A 45-year-old woman, suspected of having colon cancer, is advised to undergo a contrast-CT scan of the abdomen. She has no comorbidities and no significant past medical history. There is also no history of drug allergy. However, she reports that she is allergic to certain kinds of seafood. After tests confirm normal renal function, she is taken to the CT scan room where radiocontrast dye is injected intravenously and a CT scan of her abdomen is conducted. While being transferred to her ward, she develops generalized itching and urticarial rashes, with facial angioedema. She becomes dyspneic. Her pulse is 110/min, the blood pressure is 80/50 mm Hg, and the respirations are 30/min. Her upper and lower extremities are pink and warm. What is the most appropriate management of this patient?
- A. Administer broad-spectrum IV antibiotics
- B. Administer vasopressors (norepinephrine and dopamine)
- C. Administer IM epinephrine 1:1,000, followed by steroids and antihistamines (Correct Answer)
- D. Perform IV resuscitation with colloids
- E. Obtain an arterial blood gas analysis
Imaging study selection principles Explanation: ***Administer IM epinephrine 1:1,000, followed by steroids and antihistamines***
- This patient is experiencing **anaphylaxis** due to **radiocontrast dye**, characterized by generalized itching, urticarial rashes, angioedema, dyspnea, hypotension, and tachycardia. **Intramuscular epinephrine (1:1,000 dilution, 0.3-0.5 mg)** is the first-line treatment for anaphylaxis to reverse bronchospasm and hypotension.
- Subsequent administration of **steroids and antihistamines** helps to prevent recurrent or protracted reactions and to reduce inflammatory responses initiated by histamine and other mediators.
*Administer broad-spectrum IV antibiotics*
- This patient's symptoms are consistent with an **allergic reaction (anaphylaxis)**, not an infection, making antibiotics inappropriate.
- There is no clinical evidence of bacterial infection, such as fever, localized inflammation, or signs of sepsis beyond anaphylactic shock.
*Administer vasopressors (norepinephrine and dopamine)*
- While vasopressors can raise blood pressure, they are **second-line agents** for anaphylaxis after epinephrine.
- Epinephrine addresses both the **vasodilation** and **bronchoconstriction** components of anaphylaxis, making it superior as the initial treatment.
*Perform IV resuscitation with colloids*
- **IV fluid resuscitation** is crucial for treating the hypovolemic component of anaphylactic shock, but **crystalloids** are generally preferred over colloids initially.
- **Colloids** do not offer a significant advantage over crystalloids in anaphylaxis, and administering fluids alone would not address the bronchospasm or diffuse mediator release.
*Obtain an arterial blood gas analysis*
- While an ABG can provide information on oxygenation and acid-base status, it is **not the priority** during an acute, life-threatening anaphylactic reaction.
- Immediate management of **airway, breathing, and circulation (ABC)** with epinephrine takes precedence to stabilize the patient.
Imaging study selection principles US Medical PG Question 3: A 37-year-old woman presents to the Emergency Department after 8 hours of left sided flank pain that radiates to her groin and pelvic pain while urinating. Her medical history is relevant for multiple episodes of urinary tract infections, some requiring hospitalization, and intravenous antibiotics. In the hospital, her blood pressure is 125/83 mm Hg, pulse of 88/min, a respiratory rate of 28/min, and a body temperature of 36.5°C (97.7°F). On physical examination, she has left costovertebral tenderness and lower abdominal pain. Laboratory studies include a negative pregnancy test, mild azotemia, and a urinary dipstick that is positive for blood. Which of the following initial tests would be most useful in the diagnosis of this case?
- A. Urine osmolality
- B. Fractional excretion of sodium (FeNa+)
- C. Renal ultrasonography (Correct Answer)
- D. Contrast abdominal computed tomography
- E. Blood urea nitrogen (BUN): serum creatinine (SCr) ratio
Imaging study selection principles Explanation: ***Renal ultrasonography***
- This is the most appropriate initial imaging test to evaluate for **kidney stones** (given the flank pain radiating to groin and hematuria) and **hydronephrosis** (which can indicate obstruction) and assess for signs of **pyelonephritis** (given the history of recurrent UTIs and CVA tenderness).
- It is **non-invasive**, readily available, and avoids radiation exposure, making it suitable as a first-line diagnostic tool in this setting.
*Urine osmolality*
- This test primarily assesses the kidney's ability to **concentrate urine**, which is more relevant for evaluating fluid balance, diabetes insipidus, or other renal tubular disorders.
- It would not directly diagnose the cause of acute flank pain or urinary tract obstruction.
*Fractional excretion of sodium (FeNa+)*
- FeNa+ is used to differentiate between **prerenal azotemia** and **acute tubular necrosis**, indicating the kidney's response to hypoperfusion.
- While the patient has mild azotemia, FeNa+ would not identify the underlying cause of the flank pain, hematuria, or potential obstruction.
*Contrast abdominal computed tomography*
- While highly sensitive for diagnosing kidney stones and other renal pathologies, **contrast CT** exposes the patient to **ionizing radiation** and risks associated with contrast agents (e.g., contrast-induced nephropathy), especially with pre-existing azotemia.
- It is often reserved for cases where ultrasound is inconclusive or more detailed anatomical information is needed.
*Blood urea nitrogen (BUN): serum creatinine (SCr) ratio*
- This ratio is primarily used to differentiate between **prerenal** causes of acute kidney injury (high ratio, e.g., >20:1) and **intrinsic renal** causes (lower ratio, e.g., <15:1).
- While it can provide insight into the etiology of azotemia, it does not directly identify the cause of the patient's acute flank pain or potential urinary tract obstruction.
Imaging study selection principles US Medical PG Question 4: During the course of investigation of a suspected abdominal aortic aneurysm in a 57-year-old woman, a solid 6 × 5 cm mass is detected in the right kidney. The abdominal aorta reveals no abnormalities. The patient is feeling well and has no history of any serious illness or medication usage. She is a 25-pack-year smoker. Her vital signs are within normal limits. Physical examination reveals no abnormalities. Biopsy of the mass shows renal cell carcinoma. Contrast-enhanced CT scan indicates no abnormalities involving contralateral kidney, lymph nodes, lungs, liver, bone, or brain. Which of the following treatment options is the most appropriate next step in the management of this patient?
- A. Sunitinib
- B. Radiation
- C. Nephrectomy (Correct Answer)
- D. Interferon-ɑ (IFN-ɑ)
- E. Interleukin 2 (IL-2)
Imaging study selection principles Explanation: ***Nephrectomy***
- The patient has a **localized renal cell carcinoma (RCC)** without evidence of metastasis, as indicated by the CT scan showing no abnormalities in the contralateral kidney, lymph nodes, lungs, liver, bone, or brain.
- **Surgical removal** of the affected kidney (**nephrectomy**) is the **gold standard** and curative treatment for localized RCC.
*Sunitinib*
- **Sunitinib** is a **tyrosine kinase inhibitor** used for advanced or metastatic RCC, not for localized disease.
- It would be considered if the disease had spread beyond the kidney or if surgical resection was not feasible.
*Radiation*
- **Renal cell carcinoma** is generally considered **radioresistant**, making external beam radiation therapy ineffective as a primary treatment.
- Radiation is sometimes used for **palliative care** in metastatic RCC, for example, to relieve bone pain or brain metastases.
*Interferon-ɑ (IFN-ɑ)*
- **Interferon-ɑ** is an **immunotherapy** agent. Its use in RCC has largely been replaced by newer, more effective agents.
- It was historically used for metastatic RCC but is not indicated for localized disease and has significant side effects.
*Interleukin 2 (IL-2)*
- **High-dose interleukin 2 (IL-2)** is another **immunotherapy** agent effective in a subset of patients with metastatic RCC.
- It is not used for localized RCC and carries a risk of serious toxicity, requiring administration in specialized centers.
Imaging study selection principles US Medical PG Question 5: A 69-year-old woman presents with pain in her hip and groin. She states that the pain is present in the morning, and by the end of the day it is nearly unbearable. Her past medical history is notable for a treated episode of acute renal failure, diabetes mellitus, obesity, and hypertension. Her current medications include losartan, metformin, insulin, and ibuprofen. The patient recently started taking high doses of vitamin D as she believes that it could help her symptoms. She also states that she recently fell off the treadmill while exercising at the gym. On physical exam you note an obese woman. There is pain, decreased range of motion, and crepitus on physical exam of her right hip. The patient points to the areas that cause her pain stating that it is mostly over the groin. The patient's skin turgor reveals tenting. Radiography is ordered.
Which of the following is most likely to be found on radiography?
- A. Loss of joint space and osteophytes (Correct Answer)
- B. Posterior displacement of the femoral head
- C. Hyperdense foci in the ureters
- D. Femoral neck fracture
- E. Normal radiography
Imaging study selection principles Explanation: ***Loss of joint space and osteophytes***
- The patient's presentation with **hip and groin pain worsened by activity**, improved with rest, and associated with **crepitus** and **decreased range of motion**, is highly suggestive of **osteoarthritis**.
- **Osteoarthritis** is characterized radiographically by **loss of joint space**, **osteophytes** (bone spurs), subchondral sclerosis, and subchondral cysts.
*Posterior displacement of the femoral head*
- This finding is characteristic of a **posterior hip dislocation**, which usually presents with severe pain and an inability to bear weight after a significant traumatic event.
- While the patient fell, her symptoms are chronic and progressive, and she has signs of arthritis rather than acute dislocation.
*Hyperdense foci in the ureters*
- These would indicate **kidney stones**, which typically present with acute, severe flank pain radiating to the groin, and hematuria.
- The patient's symptoms are chronic and localized to the hip joint, making kidney stones an unlikely cause of her primary complaint.
*Femoral neck fracture*
- A **femoral neck fracture** would cause acute, severe hip pain, inability to bear weight, and often external rotation and shortening of the leg, usually following a fall.
- Although she fell, her chronic, activity-related pain and crepitus are more indicative of a degenerative process.
*Normal radiography*
- Given the patient's age, chronic and worsening hip pain, physical exam findings of crepitus and decreased range of motion, and risk factors like obesity, it is highly improbable that her hip X-rays would be normal.
- These symptoms are classic for **osteoarthritis**, which shows distinct radiographic changes.
Imaging study selection principles US Medical PG Question 6: A 67-year-old man presents to his primary care provider with bloody urine. He first noticed the blood 1 week ago. He otherwise feels healthy. His past medical history is significant for type 2 diabetes mellitus for 18 years, for which he takes insulin injections. He has smoked 30–40 cigarettes per day for the past 29 years and drinks alcohol socially. Today his vital signs include: temperature 36.6°C (97.8°F), blood pressure 135/82 mm Hg, and heart rate 105/min. There are no findings on physical examination. Urinalysis shows 15–20 red cells/high power field. Which of the following is the next best test to evaluate this patient’s condition?
- A. Prostate-specific antigen
- B. Urine cytology
- C. Urinary markers
- D. Biopsy
- E. Contrast-enhanced CT (Correct Answer)
Imaging study selection principles Explanation: ***Contrast-enhanced CT***
- This patient presents with **painless gross hematuria** and significant risk factors, including a 29-year history of **heavy smoking** and age, which raise suspicion for **urothelial carcinoma** (e.g., bladder cancer, renal cell carcinoma).
- A **contrast-enhanced CT** of the abdomen and pelvis is the most appropriate initial imaging study to evaluate the entire urinary tract for masses, stones, or other structural abnormalities causing the hematuria.
*Prostate-specific antigen*
- This test is primarily used for **prostate cancer screening** and monitoring, and while prostate issues can cause hematuria, the absence of urinary obstruction symptoms and the patient's age and smoking history make other causes more likely.
- An elevated **PSA** would not explain gross, painless hematuria in this context and would not be the initial diagnostic step for evaluating the urinary tract in general.
*Urine cytology*
- While urine cytology can detect **malignant cells**, its sensitivity for urothelial carcinoma is variable and often low, especially for low-grade tumors.
- A negative cytology does not rule out cancer, and an imaging study is still necessary to **localize the source** of bleeding and assess for structural abnormalities.
*Urinary markers*
- Various **urinary markers** (e.g., BTA stat, NMP22) are available for bladder cancer detection, but they are generally less sensitive and specific than imaging or cystoscopy.
- These markers are often used in conjunction with other tests or for surveillance, but not as the initial definitive test for **gross hematuria** in a high-risk patient.
*Biopsy*
- A biopsy is a **definitive diagnostic step** for confirming cancer but requires an identified lesion to target.
- Before a biopsy can be performed, imaging (like CT) is needed to **locate any potential tumors** in the kidneys, ureters, or bladder that would then be amenable to biopsy (e.g., via cystoscopy with biopsy or renal biopsy).
Imaging study selection principles US Medical PG Question 7: A 6-month-old boy is brought to the emergency department by his mother, who informs the doctor that her alcoholic husband hit the boy hard on his back. The blow was followed by excessive crying for several minutes and the development of redness in the area. On physical examination, the boy is dehydrated, dirty, and irritable and when the vital signs are checked, they reveal tachycardia. He cries immediately upon the physician touching the area around his left scapula. The doctor strongly suspects a fracture of the 6th, 7th, or 8th retroscapular posterior ribs. Evaluation of his skeletal survey is normal. The clinician is concerned about child abuse in this case. Which of the following is the most preferred imaging technique as the next step in the diagnostic evaluation of the infant?
- A. Bedside ultrasonography
- B. Magnetic resonance imaging
- C. Babygram
- D. Chest computed tomography scan
- E. Skeletal survey in 2 weeks (Correct Answer)
Imaging study selection principles Explanation: ***Skeletal survey in 2 weeks***
- A repeat **skeletal survey in 2 weeks** is the most appropriate next step in suspected child abuse cases with an initial normal survey, as it allows for the detection of **healing fractures** that may not be apparent immediately after injury.
- New bone formation and callus development around a fracture site become radiographically visible after approximately 7 to 14 days, improving the detection rate of subtle or undisplaced fractures.
*Bedside ultrasonography*
- While **ultrasonography** can detect acute fractures, especially in cartilage and non-ossified bones, its utility in a comprehensive assessment for multiple non-displaced rib fractures as part of a child abuse workup is limited.
- It is highly **operator-dependent** and may not provide the full skeletal overview required in suspected child abuse.
*Magnetic resonance imaging*
- **MRI** is excellent for evaluating soft tissue injuries, bone marrow edema, and non-ossified cartilaginous structures. However, it is not the primary imaging modality for detecting acute or subacute fractures of ossified bone and requires **sedation** in infants, making it less practical for routine skeletal screening.
- The **high cost** and limited availability of MRI also make it less suitable as a first-line diagnostic tool for rib fractures in this context.
*Babygram*
- A **babygram** is a single large radiograph of an infant's entire body, often used to rapidly assess for gross developmental anomalies or immediate concerns.
- It provides **less detailed imaging** of individual bones compared to a standard skeletal survey and is insufficient for reliably detecting subtle or non-displaced rib fractures.
*Chest computed tomography scan*
- A **chest CT scan** is highly sensitive for detecting acute rib fractures, even subtle ones. However, it exposes the infant to **significant radiation** and is usually reserved for specific clinical indications, such as suspected internal organ injury, rather than as a primary screening tool for rib fractures in child abuse in an otherwise stable patient.
- It does not provide a comprehensive view of the entire skeleton, which is crucial for identifying other potential abuse-related injuries elsewhere.
Imaging study selection principles US Medical PG Question 8: A 42-year-old man presents to his physician with dark urine and intermittent flank pain. He has no significant past medical history and generally is healthy. His temperature is 97.5°F (36.4°C), blood pressure is 182/112 mmHg, pulse is 85/min, respirations are 15/min, and oxygen saturation is 98% on room air. Physical examination is significant for bilateral palpable flank masses and discomfort to percussion of the costovertebral angle. Urinalysis is positive for red blood cells without any bacteria or nitrites. Which of the following diagnostic modalities should be used to screen members of this patient's family to assess if they are affected by the same condition?
- A. Voiding cystourethrogram
- B. Abdominal CT
- C. Renal biopsy
- D. Renal ultrasound (Correct Answer)
- E. Genetic sequencing
Imaging study selection principles Explanation: ***Renal ultrasound***
- **Renal ultrasound** is the preferred initial screening method for family members suspected of having **autosomal dominant polycystic kidney disease (ADPKD)** due to its non-invasiveness, accessibility, and high sensitivity for detecting cysts.
- The combination of **bilateral palpable flank masses**, **hypertension**, **dark urine (hematuria)**, and the potential for a family history strongly points to ADPKD.
*Voiding cystourethrogram*
- This imaging study is primarily used to evaluate **vesicoureteral reflux (VUR)** and lower urinary tract anatomy, which is not indicated by the patient's symptoms.
- It involves radiation exposure and catheterization, making it unsuitable for routine screening of asymptomatic family members for ADPKD.
*Abdominal CT*
- While an abdominal CT can visualize renal cysts effectively, it involves **ionizing radiation**, making it less suitable for routine screening of asymptomatic family members compared to ultrasound.
- It would typically be reserved for cases where ultrasound findings are equivocal or for evaluating complications of ADPKD.
*Renal biopsy*
- **Renal biopsy** is an invasive procedure with risks, primarily used to diagnose kidney diseases based on histopathology, especially in cases of unexplained acute kidney injury or glomerular disease.
- It is not a screening tool and would not be performed on asymptomatic family members.
*Genetic sequencing*
- **Genetic testing** can identify specific mutations in *PKD1* or *PKD2* genes, confirming ADPKD, but it is typically reserved for cases where imaging is inconclusive, for family planning, or in atypical presentations.
- It is more expensive and complex than ultrasound, making it a second-line diagnostic tool rather than a primary screening method for a large population of family members.
Imaging study selection principles US Medical PG Question 9: A 37-year-old man is presented to the emergency department by paramedics after being involved in a serious 3-car collision on an interstate highway while he was driving his motorcycle. On physical examination, he is responsive only to painful stimuli and his pupils are not reactive to light. His upper extremities are involuntarily flexed with hands clenched into fists. The vital signs include temperature 36.1°C (97.0°F), blood pressure 80/60 mm Hg, and pulse 102/min. A non-contrast computed tomography (CT) scan of the head shows a massive intracerebral hemorrhage with a midline shift. Arterial blood gas (ABG) analysis shows partial pressure of carbon dioxide in arterial blood (PaCO2) of 68 mm Hg, and the patient is put on mechanical ventilation. His condition continues to decline while in the emergency department and it is suspected that this patient is brain dead. Which of the following results can be used to confirm brain death and legally remove this patient from the ventilator?
- A. Electrocardiogram
- B. Apnea test (Correct Answer)
- C. Lumbar puncture and CSF culture
- D. Electromyography with nerve conduction studies
- E. CT scan
Imaging study selection principles Explanation: ***Correct: Apnea test***
- The **apnea test** is a **mandatory component** of brain death determination according to American Academy of Neurology (AAN) guidelines
- It directly confirms the **irreversible absence of brainstem function** by demonstrating no respiratory drive despite adequate stimulus (PaCO2 ≥60 mm Hg or 20 mm Hg rise from baseline)
- This patient already has a PaCO2 of 68 mm Hg, making the apnea test particularly relevant for confirmation
- Brain death requires both **clinical examination** (absent brainstem reflexes, coma) and a **positive apnea test** to legally declare death and discontinue mechanical ventilation
- The apnea test is performed by disconnecting the ventilator, providing supplemental oxygen, and observing for any respiratory effort while PaCO2 rises to adequate levels
*Incorrect: CT scan*
- While a **CT scan showing massive intracerebral hemorrhage with midline shift** provides anatomical evidence of severe, irreversible structural brain damage, it is **NOT sufficient to confirm brain death**
- CT imaging is used to establish the **etiology** and rule out reversible causes, but does not directly test brainstem function
- Brain death is a **clinical and functional diagnosis**, not purely an anatomical one—imaging alone cannot confirm cessation of all brain function
- A patient can have devastating structural damage on CT but still retain some brainstem reflexes
*Incorrect: Electrocardiogram*
- An **electrocardiogram (ECG)** measures cardiac electrical activity and provides no information about brain or brainstem function
- Cardiac activity commonly persists after brain death due to the heart's intrinsic automaticity
- ECG findings are irrelevant to brain death determination
*Incorrect: Lumbar puncture and CSF culture*
- **Lumbar puncture and CSF culture** are used to diagnose CNS infections (meningitis, encephalitis) or inflammatory conditions
- These tests are **completely irrelevant** for brain death diagnosis, which is based on irreversible cessation of all brain function, not infection
- In this trauma case with known intracerebral hemorrhage, LP would be contraindicated due to increased intracranial pressure and risk of herniation
*Incorrect: Electromyography with nerve conduction studies*
- **EMG and nerve conduction studies** assess peripheral nerve and muscle function, used for diagnosing neuromuscular disorders
- These tests provide no information about brain or brainstem function
- They are not part of brain death determination protocols
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