Thoracic CT

General

  • Chest Without vs Interstitial Lung Disease vs High Resolution
    • The only difference in the “Chest Without” and “Interstitial Lung Disease” protocols is the acquisition of expiratory images
    • Expiratory images do not add anything to the billing side of things. Therefore, technically these studies are billed with the same code as a chest without
    • The term “High Resolution” is an older term and has been removed from EPIC orders. However, scheduling sometimes still schedules the “CT Chest Interstitial Lung Disease” order as “CT Chest High Resolution” which is why both these entities show up on the protocol worklist. Both of these should be protocolled the same as “Interstitial Lung Disease”.
  • Low dose does NOT equal “Lung Cancer Screening”. Low dose scans can be done on normal “Chest without” protocols but that doesn’t mean they are in the screening program.
  • Basic reformations for all chest protocols
    • Axial soft tissue kernel thin (1-1.5 mm)
    • Coronal soft tissue 2 mm
    • Sagittal soft tissue 2 mm
    • Axial soft tissue (5 mm) and axial lung kernal (B60f) can also be obtained if necessary

 Chest Without

  • Indications
    • Cancer follow-ups
    • Infection
    • Pulmonary nodule
    • Initial evaluation of lymphadenopathy
    • Follow-up of aortic size
  • Acquisition Phase: Noncontrast
  • Notes
    • Most common protocol and should be the default unless there is a discrete reason for a different protocol

Chest With

  • Indications
    • Abdominopelvic findings which warrant contrast and evaluation of the chest (most common)
    • Further evaluation of lymphadenopathy following “Chest without”
    • Known mediastinal or other soft tissue mass
    • Esophageal Cancer
    • Suspected infected fluid collection (empyema, abscess)
    • Differentiation of atelectasis from other lung pathology
    • Suspected vascular pathology NOT warranting a dedicated vascular examination
  • Acquisition Phase: 50 second delay or determined by concomitant examination

Esophagram

  • Indication: Suspected esophageal leak
  • Acquisition Phase: Varies
  • Notes
    • “Post-POEM”: If the patient is post Peroral Endoscopic Myotomy (POEM), perform without and with oral contrast as to not mistake the myotomy clips for a leak
    • All other leak studies are only post oral contrast (no pre)
    • Intravenous contrast can be administered if there’s a pressing clinical need

Interstitial Lung Disease (ILD)

  • Indications
    • Suspected or known interstitial lung disease (especially initial characterization)
    • Graft vs Host
    • History of lung transplant
    • Small airways disease
    • Chronic Obstructive Pulmonary Disease (COPD)
    • Connective Tissue Disease
  • Acquisition Phase & Reconstructions
    • Standard inspiratory phase followed by expiratory phase with same parameters
    • Reconstructions use the same acquisition parameters as the inspiratory phase soft tissue kernel but are spaced 10 mm apart
  • Notes
    • Prone images are optional: If prone is on the indication request, then add it to the protocol

Lung Cancer Screening

  • Indication: Screen for lung cancer
  • Acquisition Phase: Low dose (kV usually 100 and mAs around 60)
  • Notes
    • Ensure that the pack-years are listed in the indication
    • If the patient doesn’t meet criteria (<30 pack years, outside the 55-80 years old age range), further investigation is required
    • Low dose does NOT equal “Lung Cancer Screening”. Low dose scans can be done on normal “Chest without” protocols but that doesn’t mean they are in the screening program.

Pulmonary Embolism

  • Indications
    • Suspected acute pulmonary embolism
    • Workup for chronic thromboembolic disease
  • Acquisition Phase: Dual energy with variable contrast delivery timing typically based on test bolus technique
  • Notes
    • Dual energy allows for acquisition of iodine maps and virtual low-kV monoenergetic series

Superior Vena Cava (SVC)

  • Indication: Suspected/known superior vena cava obstruction
  • Acquisition Phase: Single phase 90 second delay
  • Note: Bolus tracked at 100 HU

Tracheomalacia

  • Indications
    • Suspected/known tracheomalacia
    • Abnormality in the central airways
  • Acquisition Phase: Standard inspiratory phase followed by expiratory phase with same parameters
  • Notes
    • Similar to ILD protocol except the the cephalad field of view is higher on both inspiratory and expiratory phases (to get the upper trachea) and the caudad field of view is higher on the expiratory images to limit dose
    • Reconstructions are volumetric (i.e. not spaced every 10 mm) and include coronal and sagittal planes