April 21, 2013

Criteria and Consensus Method for Blunt Cervical Vascular Injury (BCVI) Screening with Imaging

According to the updated Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries (published on March 2013, Neurosurgery 2013;72), 
  • Computed tomography is the imaging study of choice for obtunded or un-evaluable patients with potential cervical spine injuries. (Level I)
  • Computed tomographic angiography is recommended to assess for vertebral artery injury in selected patients who meet the modified Denver Screening Criteria after blunt cervical trauma. (Level I)
Currently accepted standard used for BCVI screening is that of Modified Denver Criteria applying to acute trauma patients suffering blunt cervical vascular injury with details listed below. In this post, they have been rearranged from the original description.

Injury Mechanisms/Patterns

  • High-energy mechanism causing 1) displaced Le Fort II or III, or 2) complex mandible fracture
  • Cervical hyperextension/rotation/flexion injury with 1) midface fracture, 2) complex mandible fracture or 3) closed-head injury and diffuse axonal injury


  • Massive epistaxis
  • Central or lateralizing neurologic deficit that is unexplained or incongruent with CT
  • Transient ischemic attack or stroke after blunt neck trauma


  • Expanding neck hematoma
  • Honor syndrome
  • Cervical vascular bruit in a patient less than 50 years old with blunt neck trauma
  • Seat belt abrasion, hanging bruise, or unexplained contusion or hematoma of neck, resulting in significant cervical swelling or altered mental status

Findings on C-spine NCCT

  • Upper cervical vertebral fracture (C1-C3)
  • Cervical vertebral fracture extending through the transverse foramen
  • Cervical vertebral subluxation
  • Cervical spine fracture with cervical hyperextension/rotation/flexion injury

Findings on head NCCT

  • Acute or subacute cerebral infarction
  • Skull base fracture involving foramen lacerum, sphenoid, mastoid, or petrous bones

  1. Biffl WL, Moore EE, Offner PJ, et al. Optimizing screening for blunt cerebrovascular injuries. Am J Surg 1999;178:517–22; 
  2. Cothren CC, Moore EE, Biffl WL, et al. Cervical spine fracture patterns predictive of blunt vertebral artery injury. J Trauma 2003;55:811–3.
  3. Neurosurgery 2013;72 Supplement 2. Full-text access is FREE

April 11, 2013

Solitary Pulmonary Nodule: Definition, DDx, and Evaluation with CT

Axial scan of the lung nodule in mediastinal window reveals a solid component of the nodule without calcification
Axial scan of the lung nodule in lung window shows a lobulated, smooth margin of the nodule

Definition of SPN

  • Radiographic opacity of equal to or less than 3 cm
  • At least two thirds of margins are surrounded by lung parenchyma
  • Exclusion of lymph nodes (not always possible), atelectasis and postobstructive pneumonia
Differential Diagnosis
  • Infectious: TB, pneumonia, abscess, fungus, etc
  • Neoplastic: benign and malignant
  • Vascular: AVM, infarct, aneurysm venous varix, hematoma
  • Congenital: bronchogenic cyst, sequestration, bronchial atresia
  • Inflammatory: rheumatoid arthritis, Wegener, sarcoidosis, microscopic angiitis
  • Lymphatic: lymph node, lymphoma
  • Outside the lungs: skin nodule, nipple shadows, rib fracture, pleural lesion
  • Miscellaneous: rounded atelectasis, lipoid pneumonia, amyloidosis, etc
CT Evaluation
  • Thin-section (1 mm) contiguous images through nodule are suggested
  • Both lung and mediastinal windows obtained (lung window for margins/edges, mediastinal window for solid component)
  • Low dose (less than 80 mAs) can be used for purpose of nodule characterization
CT Characteristics
  • Growth rate: malignancy likely if doubling time = 20-400 days
  • Size: malignancy likely if size > 3 cm
  • Margin/border/edge: malignancy likely if lobulated, speculated, ragged, halo, notches
  • Calcification: attenuation > 200 HU indicates presence of calcium in the nodule. No pattern of calcification specific for malignancy
  • Cavitation: malignancy likely if irregular and thick (> 15 mm) wall

Our case: Solitary pulmonary nodule from a metastatic colon cancer

Patel VK, Naik SK, Naidich DP, et al. A practical algorithm approach to the diagnosis and management of solitary pulmonary nodules. Part 1: radiologic characteristics and imaging modalities

April 1, 2013

Focal Hepatic Hot Spot Sign

An axial CT image shows a geographic area of hypervascularity (arrow) in segment IV of the liver. Note enlarged subcutaneous collateral vessels (arrowheads)

Facts: Focal Hepatic Hot Spot

  • Focal area of enhancement in segment IV of liver due to presence of SVC obstruction
  • Occurs due to portosystemic shunting between SVC and portal vein
  • With SVC obstruction, blood may flow through internal mammary vein --> paraumbilical vein --> portal vein 
  • Other causes of focal hot spots: Budd-Chiari syndrome (caudate lobe), liver abscess, hemangioma, FNH and HCC
Three Routes of Bypass of Venous Blood in Central Thoracic Venous Obstruction
  1. Superior route: from subclavian vein to anterior jugular venous system (occuring in subclavian or brachiocephalic venous obstruction)
  2. Posterior route: azygos-hemiazygos and paravertebral systems
  3. Anterolateral route: like in our case, this is via anterior intercostal, internal mammary and long thoracic veins to IVC

Maldjian PD, Obolevich AT, Cho KC. Focal enhancement of the liver on CT: a sign of SVC obstruction. J Comput Assist Tomogr 1995;19:316-8