A 60-year-old man comes to the physician for an examination prior to a scheduled cholecystectomy. He has hypertension treated with hydrochlorothiazide. His mother had chronic granulomatous disease of the lung. He works in a glass manufacturing plant. He has smoked two packs of cigarettes daily for 38 years. His vital signs are within normal limits. Examination shows no abnormalities. Laboratory studies are within the reference range. An x-ray of the chest is shown. Which of the following is the most appropriate next step in management?

Perform diffusion capacity of the lung for carbon monoxide

Perform arterial blood gas analysis

Measure angiotensin-converting enzyme

A 41-year-old man is admitted to the emergency room after being struck in the abdomen by a large cement plate while transporting it. On initial assessment by paramedics at the scene, his blood pressure was 110/80 mm Hg, heart rate 85/min, with no signs of respiratory distress. On admission, the patient is alert but in distress. He complains of severe, diffuse, abdominal pain and severe weakness. Vital signs are now: blood pressure 90/50 mm Hg, heart rate 96/min, respiratory rate 19/min, temperature 37.4℃ (99.3℉), and oxygen saturation of 95% on room air. His lungs are clear on auscultation. The cardiac exam is significant for a narrow pulse pressure. Abdominal examination reveals a large bruise over the epigastric and periumbilical regions. The abdomen is distended and there is diffuse tenderness to palpation with rebound and guarding, worst in the epigastric region. There is hyperresonance to percussion in the epigastric region and absence of hepatic dullness in the right upper quadrant. Aspiration of the nasogastric tube reveals bloody contents. Focused assessment with sonography for trauma (FAST) shows free fluid in the pelvic region. Evaluation of the perisplenic and perihepatic regions is impossible due to the presence of free air. Aggressive intravenous fluid resuscitation is administered but fails to improve upon the patient’s hemodynamics. Which of the following is the next best step in management?

Diagnostic peritoneal lavage (DPL)

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?

Fractional excretion of sodium (FeNa+)

Contrast abdominal computed tomography

Blood urea nitrogen (BUN): serum creatinine (SCr) ratio

A 45-year-old man presents for a follow-up visit as part of his immigration requirements into the United States. Earlier this week, he was administered the Mantoux tuberculin skin test (TST). Today’s reading, 3 days after being administered the test, he shows an induration of 10 mm. Given his recent immigration from a country with a high prevalence of tuberculosis, he is requested to obtain a radiograph of the chest, which is shown in the image. Which of the following is true regarding this patient’s chest radiograph (CXR)?

If the spinous process is not in-between the two clavicular heads, the image is repeated.

Posterior ribs 9 and 10 are visible only in an expiratory film.

The right lower boundary of the mediastinal silhouette belongs to the right ventricle.

The film is taken in a supine position.

The view is anteroposterior (AP).

A 32-year-old man is brought to the emergency department after a skiing accident. The patient had been skiing down the mountain when he collided with another skier who had stopped suddenly in front of him. He is alert but complaining of pain in his chest and abdomen. He has a past medical history of intravenous drug use and peptic ulcer disease. He is a current smoker. His temperature is 97.4°F (36.3°C), blood pressure is 77/53 mmHg, pulse is 127/min, and respirations are 13/min. He has a GCS of 15 and bilateral shallow breath sounds. His abdomen is soft and distended with bruising over the epigastrium. He is moving all four extremities and has scattered lacerations on his face. His skin is cool and delayed capillary refill is present. Two large-bore IVs are placed in his antecubital fossa, and he is given 2L of normal saline. His FAST exam reveals fluid in Morison's pouch. Following the 2L normal saline, his temperature is 97.5°F (36.4°C), blood pressure is 97/62 mmHg, pulse is 115/min, and respirations are 12/min. Which of the following is the best next step in management?

Upper gastrointestinal endoscopy

A 43-year-old man presents with acute-onset left flank pain for the past 6 hours. He describes the pain as severe, intermittent, colicky, and “coming in waves”, and he points to the area of the left costovertebral angle (CVA). He says he recently has been restricting oral liquid intake to only 2 glasses of water per day based on the advice of his healer. He also reports nausea and vomiting. The patient has a history of hypertension, gout, and type 2 diabetes mellitus. He is afebrile, and his vital signs are within normal limits. On physical examination, he is writhing in pain and moaning. There is exquisite left CVA tenderness. A urinalysis shows gross hematuria. Which of the following is the next best step in the management of this patient?

Non-contrast CT of the abdomen and pelvis

Contrast CT of the abdomen and pelvis

A 69-year-old man is scheduled to undergo radical retropubic prostatectomy for prostate cancer in 2 weeks. He had a myocardial infarction at the age of 54 years. He has a history of GERD, unstable angina, hyperlipidemia, and severe osteoarthritis in the left hip. He is unable to climb up stairs or walk fast because of pain in his left hip. He had smoked one pack of cigarettes daily for 30 years but quit 25 years ago. He drinks one glass of wine daily. Current medications include aspirin, metoprolol, lisinopril, rosuvastatin, omeprazole, and ibuprofen as needed. His temperature is 36.4°C (97.5°F), pulse is 90/min, and blood pressure is 136/88 mm Hg. Physical examination shows no abnormalities. A 12-lead ECG shows Q waves and inverted T waves in leads II, III, and aVF. His B-type natriuretic protein is 84 pg/mL (N < 125). Which of the following is the most appropriate next step in management to assess this patient's perioperative cardiac risk?

Radionuclide myocardial perfusion imaging

24-hour ambulatory ECG monitoring

A 56-year-old man is brought to the emergency department 25 minutes after he was involved in a high-speed motor vehicle collision where he was the unrestrained passenger. He has severe lower abdominal and pelvic pain. On arrival, he is alert and oriented. His pulse is 95/min, respirations are 22/min, and blood pressure is 106/62 mm Hg. Examination shows severe tenderness to palpation over the lower abdomen and over the left anterior superior iliac spine. There is no limb length discrepancy. Application of downward pressure over the pelvis shows no springy resistance or instability. Rectal examination is unremarkable. A focused assessment with sonography shows no free fluid in the abdomen. There is no blood at the urethral meatus. Placement of a Foley catheter shows gross hematuria. An x-ray of the pelvis shows a fracture of the left pelvic edge. Which of the following is the most appropriate next step in management?

External fixation of the pelvis

Preoperative imaging selection for USMLE Step 3: High-Yield Surgery Lessons

Imaging Principles - To Scan or Not

Core Principle: Avoid routine, non-specific preoperative testing. Aligns with the "Choosing Wisely" campaign to reduce unnecessary procedures and costs.
When to Defer Imaging:
- Routine pre-op chest X-rays (CXRs) are not indicated for asymptomatic patients with an unremarkable history and physical exam.
- Imaging should only be ordered if results are likely to influence management.
Decision Support:
- Consult the American College of Radiology (ACR) Appropriateness Criteria® to guide evidence-based imaging selection.

⭐ In asymptomatic patients, routine preoperative chest X-rays do not decrease postoperative pulmonary complications.

ACR Criteria for Routine Chest Radiography Variants

Imaging Modalities - The Right Tool Kit

Selecting the appropriate imaging is crucial for accurate diagnosis and surgical planning. Key considerations include tissue type, urgency, and patient-specific risks like radiation exposure or contrast allergies.

Modality	Best For	Key Pre-op Use Cases	Major Risks/Cons
X-ray	Bone, air, metal	Fracture detection, line placement confirmation, bowel obstruction/ileus	Ionizing radiation
Ultrasound	Soft tissue, fluid	Gallbladder disease, DVT, abscess localization, vascular access	Operator dependent
CT Scan	Bone, soft tissue, vessels	Trauma evaluation, abscess, malignancy staging, pulmonary embolism	High radiation, contrast nephropathy/allergy
MRI	Soft tissue detail	Spinal cord/brain injury, soft tissue tumors, ligament/tendon tears, MRCP	Slow, expensive, strong magnetic fields

Contrast Considerations:
- Iodinated contrast (CT): Risk of contrast-induced nephropathy (CIN). Screen with creatinine if GFR < 60 or other risk factors exist.
- Gadolinium (MRI): Risk of nephrogenic systemic fibrosis (NSF) in severe renal disease (GFR < 30).

⭐ In suspected appendicitis, ultrasound is the preferred initial imaging in children and pregnant women to avoid radiation; CT is often used in other adults for its high accuracy.

📌 Mnemonic for MRI Contraindications (P.A.C.E.M.A.K.E.R.):

Pacemakers / ICDs
Aneurysm clips (ferromagnetic)
Cochlear implants
Electronic or Metallic implants
Artificial heart valves (older types)
Kidney disease (severe)
Eye (metal foreign body)
Rapid tissue expanders

Clinical Algorithms - Surgical Snapshots

Acute Abdomen Imaging Strategy

Trauma Imaging: The FAST & Beyond
- FAST: Focused Assessment with Sonography for Trauma. Screens for pericardial effusion, intra-abdominal free fluid.
- eFAST: Extended FAST; adds lung views for pneumothorax/hemothorax.
- Pan-Scan CT: For hemodynamically stable patients with significant mechanism of injury.

FAST exam: Splenorenal recess with and without free fluid

Suspected Vascular Obstruction
- Deep Vein Thrombosis (DVT): Doppler US is the first-line diagnostic test.
- Pulmonary Embolism (PE): CT Pulmonary Angiography (CTPA) is the gold standard.

⭐ In a hypotensive trauma patient, a positive FAST exam (free fluid) is a direct indication for an exploratory laparotomy, bypassing further imaging.

Routine preoperative imaging is not recommended for asymptomatic patients in low-risk surgery.

A baseline ECG is for patients >50 or with cardiac risk factors (HTN, DM, CAD).

Chest X-rays are for new or unstable cardiopulmonary signs/symptoms, not routine screening.

Always get a urine pregnancy test (hCG) in all females of childbearing potential.

Cardiac stress testing is for high-risk surgery in patients with poor functional capacity (<4 METs).

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