Trauma Imaging Protocols — MCQs

10 questions

Which of the following is best assessed by FAST USG?

A pregnant woman with head trauma requires a CT scan of the head. What is the most effective radiation protection measure for the fetus?

A patient involved in a Road Traffic Accident (RTA) presents with: - Absent air entry on the left side of the chest. - Tenderness in the left lower chest wall. What is the next step in the Emergency Medicine Room (EMR) management?

A man presents to the emergency department with a head injury following a vehicular accident. What is the investigation of choice?

What is the investigation of choice in a patient with traumatic paraplegia?

Gold standard investigation for hemodynamically stable blunt abdominal trauma is:

Haemodynamically unstable patient with blunt trauma to abdomen and suspected liver injury; which of the following is the first investigation performed in the emergency room?

24 yr old mother with 7 week POG presents to ANC OPD with accidental low-dose radiation exposure. What is the most appropriate immediate management?

Investigation of choice for diagnosis of splenic rupture –

Q10

What is the primary imaging modality used for diagnosing urethral trauma?

Trauma Imaging Protocols Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following is best assessed by FAST USG?

A. Liver
B. Pericardium (Correct Answer)
C. Spleen
D. Pleural cavity

Explanation: ***Pericardium*** - FAST USG is **most clinically significant** for detecting **pericardial effusions** and **cardiac tamponade** in trauma patients. - The **subxiphoid view** provides **excellent direct visualization** of the heart and pericardial space with minimal interference. - **Small volumes** of pericardial fluid (as little as 50-100 mL) are **clinically significant** and potentially life-threatening, requiring immediate intervention. - Cardiac tamponade is an **immediately reversible cause of shock** that demands urgent diagnosis and pericardiocentesis. - **Sensitivity >90%** for clinically significant pericardial effusions in the trauma setting. *Liver* - FAST assesses the **hepatorenal space (Morison's pouch)** for free fluid, not the liver parenchyma itself. - Requires **larger volumes of free fluid** (>200-500 mL) to be reliably detected in the peritoneal cavity. - Detailed assessment of actual liver injury requires **contrast-enhanced CT imaging**. *Spleen* - FAST evaluates the **splenorenal recess** for free fluid surrounding the spleen, not splenic parenchymal injury. - Detection depends on adequate volume of free fluid being present. - **CT scanning** is superior for defining splenic lacerations, hematomas, and grading injury severity. *Pleural cavity* - While Extended FAST (eFAST) can assess **pleural spaces** for effusion or pneumothorax, this is an **extension** of the standard 4-view FAST protocol. - Standard FAST focuses on the **four primary windows**: pericardial, perihepatic, perisplenic, and pelvic. - **Chest X-ray** and **CT** remain primary modalities for comprehensive thoracic assessment.

Question 2: A pregnant woman with head trauma requires a CT scan of the head. What is the most effective radiation protection measure for the fetus?

A. Using MRI instead
B. Lead apron over abdomen
C. Avoid CT, rely on clinical assessment
D. Reduced mA and kVp (Correct Answer)

Explanation: ***Reduced mA and kVp*** - **Optimizing scan parameters** (reducing mA and kVp) is the most effective way to minimize radiation dose during head CT in pregnancy. - Modern CT scanners with **iterative reconstruction** allow significant dose reduction without compromising diagnostic image quality. - The fetal dose from head CT is already negligible (< 0.01 mGy), but dose optimization further reduces any potential risk. - This directly addresses the radiation source rather than attempting to shield scatter radiation. *Lead apron over abdomen* - Lead shielding provides **minimal to no benefit** during head CT as the fetus is far from the primary beam. - Scatter radiation reaching the pelvis from head CT is negligible. - Lead aprons can interfere with **automatic exposure control (AEC)**, potentially increasing rather than decreasing dose. - Modern radiology guidelines (ACR, ICRP) no longer routinely recommend gonadal shielding for most CT examinations. *CT not recommended* - Withholding indicated imaging in trauma is **inappropriate and potentially dangerous**. - The diagnostic benefit of head CT in trauma far outweighs the negligible fetal risk. - **Maternal well-being** is the priority, and missing a critical head injury poses greater risk to both mother and fetus. *Using MRI instead* - While MRI has no ionizing radiation, it is **not appropriate for acute trauma** evaluation. - MRI takes longer to perform, requires patient cooperation, and is less readily available in emergency settings. - CT remains the **gold standard** for acute head trauma assessment.

Question 3: A patient involved in a Road Traffic Accident (RTA) presents with: - Absent air entry on the left side of the chest. - Tenderness in the left lower chest wall. What is the next step in the Emergency Medicine Room (EMR) management?

A. X-ray (Correct Answer)
B. FAST
C. DPL
D. CT

Explanation: ***X-ray*** - In a **hemodynamically stable** patient with absent air entry and chest wall tenderness post-RTA, a **chest X-ray** is the most appropriate initial imaging in the EMR. - It quickly diagnoses conditions like **pneumothorax**, **hemothorax**, or **rib fractures** and guides management decisions. - **Important**: Clinical assessment for **tension pneumothorax** (hypotension, tracheal deviation, distended neck veins) must be done first. If tension pneumothorax is suspected, **immediate needle decompression** is required without waiting for imaging. - X-ray is **rapidly available** and provides crucial information for trauma management in stable patients. *FAST* - **Focused Assessment with Sonography for Trauma (FAST)** is primarily used to detect **intra-abdominal free fluid** (hemoperitoneum) or pericardial effusion in trauma. - While valuable in RTA evaluation, it is not the primary diagnostic tool for absent air entry in the chest. - FAST has limited sensitivity for **pneumothorax** and does not visualize **rib fractures** in detail. *DPL* - **Diagnostic Peritoneal Lavage (DPL)** is an invasive procedure used to detect **intra-abdominal injury** and hemorrhage. - It has largely been replaced by FAST and CT scans due to its invasive nature and lower specificity. - DPL provides **no information about chest injuries** and is irrelevant for evaluating absent air entry. *CT* - A **CT scan** (chest CT) provides highly detailed imaging and is excellent for diagnosing specific chest injuries. - However, it is **time-consuming**, requires patient transport, and is typically reserved for **stable patients** after initial X-ray assessment. - In the immediate EMR setting, X-ray is preferred for rapid decision-making, with CT used for further evaluation if needed.

Question 4: A man presents to the emergency department with a head injury following a vehicular accident. What is the investigation of choice?

A. MRI
B. CECT
C. NCCT (Correct Answer)
D. X-ray

Explanation: ***NCCT*** - **Non-contrast Computed Tomography (NCCT)** of the head is the **investigation of choice** for acute head trauma due to its rapid acquisition, wide availability, and excellent sensitivity for detecting acute hemorrhage, fractures, and mass effects. - It rapidly identifies life-threatening conditions such as **epidural, subdural, and intracerebral hemorrhages**, which require immediate intervention. *MRI* - **MRI** is superior for detecting subtle brain tissue injuries, diffuse axonal injury, and non-hemorrhagic lesions but is generally **not the first-line investigation** in acute trauma due to longer scan times, limited availability in the emergency setting, and inability to detect acute hemorrhage as clearly as CT. - Its use is typically reserved for follow-up studies or when CT findings are inconclusive or specific soft tissue detail is required. *CECT* - **Contrast-enhanced CT (CECT)** of the head is reserved for specific indications like evaluating vascular lesions (e.g., aneurysms, arteriovenous malformations) or tumors, which are generally **not the primary concern** in the initial assessment of acute head trauma. - Administering contrast agents can delay imaging, may pose risks to patients with renal impairment or allergies, and does not significantly improve the detection of acute traumatic hemorrhage compared to NCCT. *X-ray* - **X-rays** of the skull are useful for detecting **skull fractures**, but they provide **limited information** regarding intracranial injuries or soft tissue damage, which are critical in head trauma. - They have largely been superseded by CT scans, which offer a more comprehensive view of both bony structures and intracranial contents.

Question 5: What is the investigation of choice in a patient with traumatic paraplegia?

A. Myelography
B. CT scan
C. MRI scan (Correct Answer)
D. Plain X-ray

Explanation: ***MRI scan*** - An **MRI scan** provides superior imaging of **soft tissues**, including the spinal cord, nerves, and ligaments, which are crucial for assessing damage in **traumatic paraplegia**. - It is essential for detecting **spinal cord compression**, hemorrhage, edema, and ligamentous injuries that may not be visible on other imaging modalities. *Plain X-ray* - A **plain X-ray** primarily visualizes bony structures and can detect major **fractures or dislocations** but offers limited information about the spinal cord or soft tissue damage. - It may miss subtle bony injuries and provides no information on **spinal cord integrity**, which is critical in paraplegia. *Myelography* - **Myelography** involves injecting contrast dye into the spinal canal and then performing X-rays or CT scans, which is an **invasive procedure** with potential risks. - While it can demonstrate **spinal cord compression** indirectly, it has largely been replaced by MRI due to its invasiveness and MRI's direct visualization capabilities. *CT scan* - A **CT scan** is excellent for evaluating **bony injuries**, such as vertebral fractures and alignment, with good detail. - However, it is less effective than MRI for directly visualizing the **spinal cord itself** and assessing soft tissue damage, which is paramount in paraplegia.

Question 6: Gold standard investigation for hemodynamically stable blunt abdominal trauma is:

A. DPL
B. FAST scan
C. Plain X-ray
D. CT with contrast (Correct Answer)

Explanation: ***CT with contrast*** - **Computed tomography (CT) with intravenous contrast** is considered the **gold standard** for evaluating hemodynamically stable patients with blunt abdominal trauma due to its high sensitivity and specificity in detecting solid organ injuries, free fluid, and active extravasation. - It provides detailed anatomical information, helping to grade injuries and guide management decisions. *DPL* - **Diagnostic peritoneal lavage (DPL)** is an invasive procedure primarily used in hemodynamically unstable patients to rapidly detect intra-abdominal hemorrhage. - It has a high false-positive rate and is less specific for identifying the exact source or extent of injury compared to CT. *FAST scan* - The **Focused Assessment with Sonography for Trauma (FAST) scan** is a rapid, non-invasive imaging modality used to detect free fluid (usually blood) in the peritoneum, pericardium, and pleural spaces. - While useful for initial screening and in hemodynamically unstable patients, it is operator-dependent and cannot reliably detect retroperitoneal injuries or solid organ damage not associated with significant free fluid. *Plain X-ray* - **Plain X-rays** (e.g., abdominal X-rays) have very limited utility in assessing blunt abdominal trauma as they poorly visualize soft tissues and cannot detect hemorrhage or solid organ injury. - They are primarily used to evaluate for skeletal injuries or free air suggesting a ruptured viscus, which are not the primary concerns in comprehensive abdominal trauma assessment.

Question 7: Haemodynamically unstable patient with blunt trauma to abdomen and suspected liver injury; which of the following is the first investigation performed in the emergency room?

A. CT Scan
B. Diagnostic peritoneal lavage
C. FAST (Correct Answer)
D. Standing X ray Abdomen

Explanation: ***FAST*** - For a **hemodynamically unstable** patient with blunt abdominal trauma, **Focused Assessment with Sonography for Trauma (FAST)** is the quickest and most appropriate initial investigation to detect **free fluid** (indicating hemorrhage) in the abdomen or pericardium. - Its **rapidity and non-invasiveness** make it ideal for immediate decision-making regarding surgical intervention. *CT Scan* - **CT scans** provide detailed anatomical information but require the patient to be **hemodynamically stable** and are time-consuming for an emergency assessment. - Moving an unstable patient to radiology for a CT scan can significantly **delay definitive treatment**. *Diagnostic peritoneal lavage* - While historically used, **diagnostic peritoneal lavage (DPL)** is an **invasive procedure** that is less commonly performed now due to the availability of FAST. - It has a high rate of **false positives** and potential complications, making it less favorable as a first-line investigation. *Standing X ray Abdomen* - A **standing X-ray of the abdomen** is primarily useful for detecting **free air under the diaphragm** (indicating bowel perforation) or major bony injuries. - It is **poor at detecting free fluid** or organ injury, which is the primary concern in suspected liver trauma in an unstable patient.

Question 8: 24 yr old mother with 7 week POG presents to ANC OPD with accidental low-dose radiation exposure. What is the most appropriate immediate management?

A. Reassure and continue pregnancy (Correct Answer)
B. Perform detailed fetal anomaly scan
C. Advise medical termination of pregnancy
D. Advise genetic counseling and testing

Explanation: ***Reassure and continue pregnancy*** - **Low-dose radiation exposure** (typically defined as <50 mGy) during pregnancy is generally associated with a very low risk of fetal anomalies or adverse outcomes. The patient should be reassured that the risk to the fetus is minimal. - The threshold for concern for teratogenic effects from radiation is significantly higher than a low dose, and **medical termination of pregnancy** is not indicated in such cases. - This is the most appropriate **immediate management** for accidental low-dose radiation exposure at 7 weeks gestation. *Perform detailed fetal anomaly scan* - While anomaly scans are part of routine prenatal care, performing an immediate, detailed scan solely due to **low-dose radiation exposure** at 7 weeks is not the most appropriate *immediate* management. The risk of anomalies from such exposure is extremely low and unlikely to be detectable at 7 weeks. - A more detailed scan may be considered at later gestational ages (e.g., 18-20 weeks) as part of standard care, but not as an emergency response to low-dose exposure. *Advise medical termination of pregnancy* - Medical termination is **not indicated** for accidental **low-dose radiation exposure**. Termination is only considered in cases of *extremely high* and confirmed doses (e.g., >100 mGy), which carry a significant risk of severe fetal anomalies or mortality. - Such high doses are rare in accidental exposures and would necessitate a thorough dose assessment by a radiation physicist before considering any drastic measures. - Since the scenario specifies low-dose exposure, termination would be inappropriate and potentially harmful counseling. *Advise genetic counseling and testing* - **Genetic counseling** and testing would be indicated for known genetic risks, advanced maternal age, or suspicion of chromosomal abnormalities, none of which are suggested by accidental **low-dose radiation exposure**. - Radiation-induced effects are typically teratogenic rather than directly causing inheritable genetic mutations that would be detected by standard genetic testing.

Question 9: Investigation of choice for diagnosis of splenic rupture –

A. MRI
B. Peritoneal lavage
C. Ultrasound
D. CT scan (Correct Answer)

Explanation: **CT scan** - A **CT scan** with intravenous contrast is the investigation of choice for splenic rupture due to its high sensitivity and specificity in detecting **splenic injury**, **hematomas**, and **free intraperitoneal fluid**. - It provides detailed anatomical information, crucial for grading the injury and guiding management decisions, especially in hemodynamically stable patients. *MRI* - **MRI** offers excellent soft tissue contrast, but it is **time-consuming** and often **not readily available** in emergency settings for acute trauma. - It is typically reserved for more chronic or complex cases where detailed soft tissue characterization is not immediately needed in acute trauma. *Peritoneal lavage* - **Diagnostic peritoneal lavage (DPL)** is an **invasive procedure** that is less specific than imaging for diagnosing splenic rupture. - It detects the presence of **intraperitoneal bleeding** but does not localize the injury or provide information about the extent of organ damage. *Ultrasound* - **Ultrasound (FAST exam)** is a rapid, non-invasive tool for detecting **free fluid** in the abdomen but has limited sensitivity for directly visualizing the spleen or accurately grading splenic injuries. - While useful for rapid assessment of **hemodynamically unstable** patients, a **negative FAST exam does not rule out splenic injury**, especially in stable patients.

Question 10: What is the primary imaging modality used for diagnosing urethral trauma?

A. Ascending urethrogram (Correct Answer)
B. Descending urethrogram
C. USG
D. CT scan

Explanation: ***Ascending urethrogram*** - An **ascending urethrogram** (also known as a retrograde urethrogram) is the **gold standard** for diagnosing urethral trauma. - It involves injecting contrast material directly into the urethra to visualize its integrity and identify any extravasation, strictures, or ruptures. *Descending urethrogram* - A descending urethrogram (or voiding cystourethrogram) is primarily used to evaluate the **bladder and urethra during urination**, often for vesicoureteral reflux or bladder neck dysfunction. - It is not the primary diagnostic tool for acute urethral trauma, as it requires the patient to void, which might be painful or difficult with an injured urethra. *USG* - **Ultrasound** (USG) can be used to assess the presence of peri-urethral hematomas or fluid collections but is generally **not sufficient to definitively diagnose urethral integrity** or the exact location and extent of a tear. - Its utility in urethral trauma is limited compared to direct contrast imaging of the urethra. *CT scan* - A **CT scan** of the pelvis can identify associated injuries, such as **pelvic fractures** or hematomas, that often accompany urethral trauma. - However, it is **less sensitive for direct visualization of the urethral lumen** and diagnosing the extent of a urethral injury compared to an ascending urethrogram.

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