Interpreting Emergency Imaging

Interpreting Emergency Imaging

Structures systematic, modality-specific review of emergency CT, X-ray, and point-of-care ultrasound findings with critical result identification, structured reporting, and closed-loop communication documentation.

Why This Skill Exists

Emergency imaging interpretation errors contribute to approximately 4% of ED diagnostic errors, with missed findings on CT and plain radiographs among the top sources of malpractice claims in emergency medicine. Critical findings like pneumothorax, aortic dissection, free air, and intracranial hemorrhage require not only accurate identification but also documented closed-loop communication to the treating team. Joint Commission National Patient Safety Goals mandate a structured process for reporting critical imaging results.

Point-of-care ultrasound (POCUS) has become a core EM competency, but without systematic documentation of findings, image archival, and quality assurance, POCUS studies create liability rather than reducing it. This skill ensures every emergency imaging interpretation follows a systematic search pattern, documents both positive and pertinent negative findings, and maintains a defensible communication chain.

Checkpoint A: Pre-Draft Intake (Mandatory)

1. What is the clinical indication and specific question the imaging is intended to answer?
2. What modality was used (CT with/without contrast, plain radiograph, POCUS, MRI)?
3. For CT: was IV contrast given? Was oral contrast used? Were there any contrast reactions?
4. For POCUS: who performed the study, what probe was used, what protocol was followed (FAST, RUSH, cardiac, lung)?
5. Is there any relevant prior imaging available for comparison?
6. What is the patient's clinical status (stable vs. unstable, pre-operative, trauma activation level)?
7. Are there known allergies to contrast, renal function concerns (GFR), or pregnancy status?
8. Has a preliminary wet read been communicated, or is the attending radiologist read pending?

Documents to Request

• Imaging order with clinical indication
• Prior imaging studies for comparison (dates and findings)
• Radiology preliminary and final reports
• POCUS image archive with interpretation note
• Contrast administration record (type, volume, route, any reactions)
• Lab results relevant to imaging (creatinine/GFR for contrast, coagulation for intervention)
• Clinical notes providing context for imaging indication
• Communication log for critical results

Step 1: Plain Radiograph Systematic Review

Chest X-Ray (CXR) — ABCDEFGHI Approach

Extremity/Trauma X-Ray — Rule of 2s

• 2 views minimum (AP and lateral)
• 2 joints (above and below the fracture)
• 2 times (compare with prior if available)
• 2 sides (comparison view for pediatric patients)

Step 2: CT Interpretation by Clinical Scenario

CT Head Without Contrast (Trauma/Stroke)

Systematic search: scalp soft tissue → calvarium → epidural space → subdural space → subarachnoid space → parenchyma → ventricles → midline shift → posterior fossa → skull base → orbits

CT Abdomen/Pelvis (Trauma — FAST negative but mechanism)

Search pattern: solid organs → hollow viscera → mesentery → retroperitoneum → pelvis → spine → soft tissues

Critical findings requiring immediate communication:

1. Active contrast extravasation (blush) — indicates ongoing hemorrhage
2. Free intraperitoneal fluid without solid organ injury — consider mesenteric/bowel injury
3. Pneumoperitoneum — hollow viscus perforation
4. Grade IV-V solid organ injury (AAST grading)
5. Aortic injury (intimal flap, pseudoaneurysm, rupture)

CT Angiography Chest (PE Protocol)

• Assess pulmonary arteries from main PA through segmental branches
• Document clot location (saddle, lobar, segmental, subsegmental)
• Right heart strain signs: RV/LV ratio >0.9, interventricular septal bowing, PA diameter >main aorta
• Incidental findings: aortic dissection, pericardial effusion, lung nodules

Step 3: Point-of-Care Ultrasound (POCUS) Documentation

FAST Exam (Focused Assessment with Sonography in Trauma)

POCUS documentation requirements:

1. Clinical indication
2. Views obtained (and any views not obtained with reason)
3. Machine/probe type used
4. Findings (positive and pertinent negative)
5. Clinical interpretation and action taken
6. Images archived to PACS or medical record
7. QA review submission if required by facility

Step 4: Critical Result Communication (Closed-Loop)

For critical findings, document the communication chain:

1. Finding identified: Exact finding, time identified, identified by whom
2. Communicated to: Name, role, and contact method (direct verbal, phone, secure message)
3. Read-back confirmed: Receiving provider verbalized understanding of the finding
4. Action taken: What clinical intervention resulted from the communication
5. Time of communication: Must be within facility-defined critical result timeframe (typically 15-60 minutes)

Critical findings requiring immediate communication:

• Intracranial hemorrhage or mass effect with herniation
• Aortic dissection or rupture
• Tension pneumothorax
• Pulmonary embolism with RV strain
• Free intraperitoneal air
• Active hemorrhage with contrast extravasation
• Cervical spine fracture with canal compromise
• Ectopic pregnancy with free fluid

Step 5: Structured Reporting and Discrepancy Management

When preliminary ED interpretation differs from final radiology read:

1. Document time the discrepancy was identified
2. Assess clinical significance (would the discrepancy change management?)
3. Attempt to reach the patient if discharged and finding is clinically significant
4. Document callback attempt, patient notification, and revised plan
5. Enter the discrepancy into the facility's radiology-ED discrepancy tracking system

Checkpoint B: Post-Draft Alignment (Mandatory)

1. Was a systematic search pattern followed for each imaging modality (not just looking for expected findings)?
2. Are both positive findings and pertinent negatives documented?
3. Is critical result communication documented with closed-loop confirmation?
4. For POCUS: are images archived and QA-compliant?
5. Has any preliminary-to-final read discrepancy been addressed with patient callback if needed?

Quality Audit

Guidelines

1. Never rely solely on targeted review—systematic search patterns catch incidental findings that targeted reading misses; missed incidental aortic aneurysm on abdominal CT is a common malpractice finding
2. POCUS is an extension of the physical exam but must be documented with the same rigor as radiology-ordered studies—undocumented POCUS creates liability without benefit
3. CT in pregnancy: risk-benefit discussion must be documented; estimated fetal dose from a standard CT abdomen/pelvis is ~25 mGy, well below the 50 mGy threshold for deterministic effects
4. Pediatric imaging: apply ALARA principles and use Image Gently protocols; always consider ultrasound before CT for appendicitis and intussusception
5. Oral contrast in trauma CT: most trauma centers have moved to IV-only protocols; oral contrast delays scanning and rarely changes management in acute trauma
6. The wet read is not the final read—document that a preliminary interpretation was made and that the final radiology interpretation will be reviewed when available
7. Incidental findings (lung nodules on trauma CT, adrenal masses, renal cysts) require documented follow-up recommendations per Fleischner Society or ACR Incidental Findings Committee guidelines