Abdominal Trauma Imaging — MCQs
What is the investigation of choice for blunt abdominal trauma in an unstable patient?
Investigation of choice for diagnosis of splenic rupture –
What is the investigation of choice in a patient with blunt abdominal trauma with hematuria?
A man comes to the emergency department with stab injury to left flank. He has stable vitals. What would be the next step in management?
Most sensitive investigation for abdominal trauma in a hemodynamically stable patient is-
How do you differentiate between mechanical obstruction and paralytic ileus?
Which of the following statements about CT imaging is the MOST accurate?
What is the investigation of choice in a patient with blunt abdominal trauma with hematuria?
Which of the following is best assessed by FAST USG?
The most appropriate investigation to diagnose and determine the extent of renal injury in a 15-year-old boy who presents with hematuria and left-sided abdominal pain 48 hours after sustaining a blunt abdominal injury, with a pulse rate of 96/minute, blood pressure of 110/70 mmHg, hemoglobin of 10.8 gm%, and packed cell volume of 31%, would be-
Abdominal Trauma Imaging Indian Medical PG Practice Questions and MCQs
Question 1: What is the investigation of choice for blunt abdominal trauma in an unstable patient?
- A. X-ray abdomen
- B. MRI
- C. USG (Correct Answer)
- D. Diagnostic Peritoneal Lavage (DPL)
Explanation: ***USG (FAST Exam)*** - In an **unstable patient** with blunt abdominal trauma, **Focused Assessment with Sonography for Trauma (FAST) exam** is the investigation of choice. - It is **rapid, non-invasive, and bedside**, allowing immediate detection of **free fluid** (blood) in the peritoneal cavity, pericardium, and pleural spaces without transporting the patient. - Guides immediate decision for **laparotomy** in hemodynamically unstable patients. - **Note:** In **stable patients**, **CT abdomen** is the gold standard as it provides detailed anatomical information, but it requires patient transport and time. *X-ray abdomen* - Provides limited information in blunt trauma, primarily showing **free air** (bowel perforation) or **bony fractures**. - **Not sensitive** for detecting intraperitoneal bleeding, which is the primary concern in unstable patients. *MRI* - Offers excellent soft tissue detail but is **time-consuming** and requires the patient to be **hemodynamically stable**. - **Impractical** for unstable trauma patients requiring rapid assessment and intervention. *Diagnostic Peritoneal Lavage (DPL)* - An **invasive procedure** that is sensitive for detecting intra-abdominal hemorrhage. - Has largely been **replaced by FAST exam** in most trauma centers due to FAST being non-invasive, rapid, and repeatable. - DPL has a **higher false-positive rate** and cannot identify the source of bleeding.
Question 2: 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 3: What is the investigation of choice in a patient with blunt abdominal trauma with hematuria?
- A. USG of the abdomen
- B. Retrograde urogram
- C. IVP
- D. CECT (Correct Answer)
Explanation: ***Correct Answer: CECT*** - **Contrast-enhanced computed tomography (CECT)** is the investigation of choice for evaluating blunt abdominal trauma with hematuria as it accurately assesses the extent of injury to the **kidneys, ureters, bladder**, and surrounding structures. - It provides detailed images for detecting **renal lacerations, hematomas, urine extravasation**, and other abdominal organ injuries. - **Gold standard** in trauma protocols for comprehensive evaluation of renal and abdominal injuries. *Incorrect: USG of the abdomen* - **Ultrasound** can identify gross abnormalities like large hematomas or free fluid but is less sensitive than CECT for subtle renal injuries or collecting system disruptions. - It is often used as an initial screening tool (FAST exam) but not the definitive investigation of choice in this context. *Incorrect: Retrograde urogram* - A **retrograde urogram** primarily evaluates the **lower urinary tract** (ureters and bladder) by injecting contrast directly into the urethra. - It is not suitable for assessing the extent of renal parenchymal injury or other abdominal organ damage in blunt trauma. *Incorrect: IVP* - **Intravenous pyelogram (IVP)** uses intravenous contrast to visualize the kidneys, ureters, and bladder, but it has largely been replaced by CECT due to its lower sensitivity and specificity for traumatic injuries. - It provides less detailed anatomical information about surrounding soft tissues and can miss subtle parenchymal or vascular injuries.
Question 4: A man comes to the emergency department with stab injury to left flank. He has stable vitals. What would be the next step in management?
- A. Diagnostic peritoneal lavage
- B. Laparotomy
- C. CECT (Correct Answer)
- D. Laparoscopy
Explanation: ***CECT*** - A **Contrast-Enhanced Computed Tomography (CECT)** scan is the preferred initial diagnostic step for a hemodynamically stable patient with a stab wound to the flank. - It effectively assesses the **depth of penetration** and identifies potential internal organ injuries in the abdomen or retroperitoneum, guiding further management. *Diagnostic peritoneal lavage* - **Diagnostic peritoneal lavage (DPL)** is less commonly used for stab wounds in hemodynamically stable patients due to its **invasiveness** and lower specificity compared to CT scans. - While it can detect peritoneal penetration or significant hemorrhage, it often leads to **unnecessary laparotomies** and is not as precise in identifying specific organ injuries. *Laparotomy* - **Laparotomy** (surgical exploration) is indicated for **hemodynamically unstable** patients or those with definitive signs of peritonitis or evisceration. - Since the patient has **stable vitals**, immediate laparotomy is not the next step, as diagnostic imaging is needed first. *Laparoscopy* - **Laparoscopy** is a minimally invasive surgical procedure that can be used diagnostically or therapeutically in stable patients. - However, in the initial assessment of a flank stab wound, a **CECT scan** is typically performed first to get a comprehensive view of potential organ damage before considering a more invasive procedure like laparoscopy.
Question 5: Most sensitive investigation for abdominal trauma in a hemodynamically stable patient is-
- A. Ultrasonography (FAST)
- B. Diagnostic peritoneal lavage (DPL)
- C. MRI (Magnetic Resonance Imaging)
- D. CT Scan (Computed Tomography) (Correct Answer)
Explanation: ***CT Scan (Computed Tomography)*** - **CT scans** offer superior anatomical detail and can accurately detect organ damage, hemorrhage, and other injuries in **hemodynamically stable** patients with abdominal trauma. - It is considered the **most sensitive** and specific imaging modality for evaluating blunt and penetrating abdominal trauma when the patient can tolerate the study. *Ultrasonography (FAST)* - While effective for detecting **free fluid** (blood) in specific abdominal areas, **Focused Assessment with Sonography for Trauma (FAST)** has lower sensitivity for solid organ injuries or bowel perforations. - Its primary role is rapid assessment for **hemoperitoneum** to guide immediate management in unstable patients, not detailed injury characterization. *Diagnostic peritoneal lavage (DPL)* - **DPL** is an invasive procedure with high sensitivity for detecting **intraperitoneal bleeding**, but it does not identify specific organ injuries or retroperitoneal hemorrhage. - It is rarely used in hemodynamically stable patients due to its invasiveness and the availability of more detailed imaging techniques. *MRI (Magnetic Resonance Imaging)* - **MRI** provides excellent soft tissue contrast but is typically too **time-consuming** and less accessible in urgent trauma settings compared to CT. - It's generally not the first-line investigation for acute abdominal trauma due to motion artifacts and limited utility in detecting air or bone injuries.
Question 6: How do you differentiate between mechanical obstruction and paralytic ileus?
- A. Presence of multiple air-fluid levels in the bowel (Correct Answer)
- B. Presence of abdominal distension
- C. Absence of rectal gas shadow in imaging studies
- D. Elevation of hemidiaphragm on imaging
Explanation: ***Presence of multiple air-fluid levels in the bowel*** - The presence of multiple **air-fluid levels** on upright abdominal X-rays or CT scans is a hallmark of **mechanical bowel obstruction**, indicating a blockage preventing the normal progression of gas and fluid. - In a paralytic ileus, bowel loops are generally **gas-filled but without distinct air-fluid levels**, as there is no physical blockage impeding fluid movement. *Absence of rectal gas shadow in imaging studies* - An **absent rectal gas shadow** can be seen in both severe **mechanical obstruction** and **paralytic ileus**, particularly if the obstruction or ileus is significant and prolonged, making it a less specific differentiating feature. - While it suggests an empty distal bowel, it does not reliably distinguish between the two conditions without additional findings. *Presence of abdominal distension* - **Abdominal distension** is a common finding in both **mechanical obstruction** (due to trapped gas and fluid proximal to the blockage) and **paralytic ileus** (due to generalized bowel dilation). - Therefore, its presence alone does not help differentiate between these two conditions. *Elevation of hemidiaphragm on imaging* - An **elevated hemidiaphragm** can occur in various abdominal conditions, including large collections of fluid or gas pushing up the diaphragm, or conditions affecting diaphragmatic motion itself (e.g., phrenic nerve palsy). - It is not a specific finding to differentiate between **mechanical obstruction** and **paralytic ileus**.
Question 7: Which of the following statements about CT imaging is the MOST accurate?
- A. Water has a Hounsfield unit (HU) of zero. (Correct Answer)
- B. CT head dose remains constant regardless of the protocol used.
- C. CT cannot detect gallstones under any circumstances.
- D. CT uses unfiltered x-ray beams.
Explanation: ***Water has a Hounsfield unit (HU) of zero.*** - The **Hounsfield unit (HU)** scale is a quantitative scale used to describe radiodensity in CT scans, where **water is defined as 0 HU**. - This establishes a crucial reference point for measuring the attenuation of other tissues, which can range from approximately **-1000 HU for air** to **+1000 HU or more for dense bone**. *CT head dose remains constant regardless of the protocol used.* - The **radiation dose** in CT scans is highly variable and depends significantly on the **protocol used**, including factors like mA, kVp, pitch, and scan length. - **Dose optimization techniques** and protocol adjustments are routinely employed to minimize patient exposure while maintaining diagnostic image quality. *CT cannot detect gallstones under any circumstances.* - While **ultrasound (US)** is the primary modality for detecting gallstones, CT can visualize them, especially if they are **calcified** or of mixed composition. - **Non-calcified gallstones** may be more challenging to detect on CT, but they are not impossible to see, particularly with current generation scanners and appropriate windowing. *CT uses unfiltered x-ray beams.* - CT scanners use **filtered x-ray beams** to provide higher quality images and reduce patient dose. - **Filtration (e.g., aluminum or copper)** removes low-energy x-rays, which would otherwise be absorbed by the patient without contributing to image formation.
Question 8: What is the investigation of choice in a patient with blunt abdominal trauma with hematuria?
- A. Contrast enhanced computed tomography (Correct Answer)
- B. Retrograde urogram
- C. Intravenous urogram
- D. Ultrasonography of abdomen
Explanation: ***Contrast enhanced computed tomography (CECT)*** - **CECT** is the **investigation of choice** for evaluating solid organ injuries, including renal trauma, in hemodynamically stable patients with blunt abdominal trauma and hematuria. - It provides detailed imaging of the kidneys, urinary tract, and surrounding structures, allowing for the classification of injury severity and identification of associated injuries. *Retrograde urogram* - A retrograde urogram is primarily used to evaluate the **lower urinary tract** (urethra and bladder) for strictures or injuries, specifically when there is a suspicion of urethral injury. - It is not the primary imaging modality for assessing renal parenchymal or collecting system injuries from blunt trauma. *Intravenous urogram (IVU)* - While an IVU can assess the upper urinary tract, it has largely been replaced by **CECT** in the acute trauma setting due to CECT's superior resolution and ability to evaluate renal parenchyma and other abdominal organs. - IVU exposes the patient to radiation and requires contrast administration, and it may not adequately visualize subtle renal injuries or hematomas as effectively as CECT. *Ultrasonography of abdomen* - **Ultrasound** is useful for rapidly detecting free fluid (suggesting hemorrhage) or gross hydronephrosis in trauma, but it has limited sensitivity for diagnosing specific renal parenchymal injuries or urinary extravasation. - Its role in blunt abdominal trauma with hematuria is often as an initial screening tool, but it is not sufficient for definitive diagnosis or grading of renal injuries.
Question 9: 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 10: The most appropriate investigation to diagnose and determine the extent of renal injury in a 15-year-old boy who presents with hematuria and left-sided abdominal pain 48 hours after sustaining a blunt abdominal injury, with a pulse rate of 96/minute, blood pressure of 110/70 mmHg, hemoglobin of 10.8 gm%, and packed cell volume of 31%, would be-
- A. Sonographic evaluation of abdomen
- B. Intravenous pyelography
- C. Contrast enhanced computed tomography (Correct Answer)
- D. MR urography
Explanation: ***Contrast enhanced computed tomography*** - **CT with intravenous contrast** is the gold standard for evaluating **renal trauma**, providing detailed anatomical information on the extent of injury, including lacerations, hematomas, and urinary extravasation, which might be missed by other modalities. - It rapidly assesses the **parenchyma**, **collecting system**, and surrounding structures, allowing for proper staging of the injury and guiding management decisions. *Sonographic evaluation of abdomen* - **Ultrasound** is useful for rapidly detecting **free fluid** (e.g., blood) in the abdomen and assessing major organ integrity, but its ability to characterize renal parenchymal injuries or urinary extravasation is limited. - It is **operator-dependent** and often insufficient for detailed staging of renal trauma compared to CT. *Intravenous pyelography* - **IVP** primarily evaluates the **collecting system** and ureteral patency but has limited sensitivity for assessing renal parenchymal injuries or perinephric hematomas. - It involves radiation exposure and a contrast load, and generally provides **less anatomical detail** than modern CT scans. *MR urography* - **MR urography** provides excellent soft tissue contrast without ionizing radiation, but it is typically **less readily available** in an emergency setting and takes longer to perform than CT. - Its role in acute trauma is usually reserved for cases where **iodinated contrast is contraindicated** (e.g., severe allergy, renal insufficiency) or when specific soft-tissue detail is crucial for follow-up.
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