What are the guidelines for a CT (Computed Tomography) scan of the chest and pelvis?

Guidelines for CT Chest and Pelvis

CT of the chest and pelvis with IV contrast is the recommended imaging modality for suspected distant recurrence of cancer or evaluation of major blunt trauma, while non-contrast CT should be avoided due to lower sensitivity for detecting vascular and visceral injuries. 1

Indications for CT Chest and Pelvis

Cancer Evaluation and Surveillance

• Suspected Distant Recurrence:

  • For breast cancer patients with suspected distant recurrence based on symptoms, physical examination, or laboratory values, CT chest, abdomen, and pelvis with IV contrast is recommended by NCCN 1
  • For cervical cancer (stage II-IV), CT of abdomen and pelvis with IV contrast may be used within 3-6 months after completion of therapy, though PET/CT is preferred 1
  • For vulvar cancer recurrence, contrast-enhanced CT of chest, abdomen, and pelvis is usually appropriate 1

• Active Surveillance:

  • For renal cell carcinoma, CT abdomen with IV contrast is preferred over CT abdomen and pelvis for T1a masses 1
  • For testicular cancer follow-up after chemotherapy, abdominal/pelvic CT is recommended as clinically indicated 1

• Important Caveat: Routine imaging surveillance in asymptomatic cancer patients is generally NOT recommended:

  • ASCO, NCCN, ESMO, and ESO all recommend against routine use of imaging to screen for distant disease recurrence in breast cancer 1
  • For stage I cervical cancer patients, imaging should be based on symptoms and clinical concerns 1

Trauma Evaluation

• Major Blunt Trauma:
  • CT of chest, abdomen, and pelvis with IV contrast has greater sensitivity for detecting visceral organ and vascular injuries compared to non-contrast CT 1
  • Indications for whole-body CT include high-velocity (>35 mph) motor vehicle collisions, rollover accidents, motorcycle trauma, bicycle injuries, pedestrian collisions, and falls from >15 feet 1
  • Noncontrast CT should be avoided due to lower sensitivity for detecting vascular injuries 1

Technical Considerations

Contrast Administration

• IV contrast significantly improves detection of:

  • Vascular injuries in trauma 1
  • Active arterial bleeding to abdominopelvic viscera 1
  • Tumor recurrence and metastases 1

• Oral contrast:

  • Not recommended in trauma as it can delay diagnosis without altering sensitivity or specificity 1

Protocol Selection

• Single-phase study is appropriate for most clinical questions 1
• For suspected vascular injuries, CTA (CT angiography) in arterial phase is warranted 1
• Dual-phase studies (without and with contrast) are generally unnecessary 1

Radiation Considerations

• CT scanning accounts for a significant portion of radiation exposure in diagnostic imaging 2
• In large hospitals, CT scanning can account for about 15% of procedures but 75% of the diagnostic radiation dose 2
• Consider radiation exposure particularly in patients requiring multiple scans or frequent admissions 3

Common Pitfalls to Avoid

1. Overuse of CT imaging:

   • Avoid routine surveillance imaging in asymptomatic cancer patients 1
   • Consider that the vast majority (96%) of head CT scans in frequently admitted patients lack clinically significant findings 3

2. Inappropriate protocol selection:

   • Non-contrast CT has lower sensitivity for detecting vascular and visceral injuries 1
   • Unnecessary multiphase studies increase radiation exposure without adding diagnostic value 1

3. Inconsistent measurements:

   • Using different imaging modalities can result in inconsistent measurements that affect patient care 1
   • Consider standardizing measurement techniques (2D vs. 3D) for tumor assessment 1

By following these evidence-based guidelines, clinicians can optimize the use of CT chest and pelvis imaging to improve patient outcomes while minimizing unnecessary radiation exposure and healthcare costs.