Table 2 Checklist of brain CT reading in patients with suspected acute ischemic stroke

1. Check patient’s ID

2. Reading bone windows [13, 29]

 Identify skull fracture

 Identify skull destruction

 Identify skull mass lesion or osteoblastic lesion

3. Sequential reading from extra-axial to intra-axial [16]

4. Identify the image symmetry of the bilateral hemispheres

 Extra-axial lesions

  Epidural and subdural space [29]

  Interhemispheric fissure

  Sylvian fissure

  Ventricles

   Lateral ventricles

   Anterior and posterior horns of lateral ventricles

   Temporal horns of lateral ventricles

   Fourth ventricle

  Specific regions

   Cerebellopontine angle

   Sella lesion

  Vessels

   Hyperdense MCA sign [15]

   Hyperdense BA sign [14]

   Veins: Dense sinus signs of CVT [22]

  Orbital cavity (Ophthalmic vein enlargement, orbital mass) [17]

 Intra-axial lesion

  ACA territory

  PCA territory

  MCA territory, basal ganglia and thalamus [24]

  Borderzone areas [26]

   MCA-ACA border zone

   MCA-PCA border zone

  Temporal lobes

  Mass effect, mid-line shift, or herniation [25]

  Brain stem

   Mid-brain

   Pons

   Medulla

  Cerebellum: symmetry, hyperdensity, hypodensity of the cerebellar hemispheres.

5. Identify abnormal densities on brain CT [27, 28]

 Identify hyper-density lesions

  Hematoma density

  Physiological calcification density

 Identify low density lesions

  Very low density (CSF and old lesions)

  Low density (edematous lesion and recent infarcts)

 Identify heterogeneous density lesions

  Hematoma with blended sign [18], whirl sign [19], spot sign [21], or black hole sign [20]

  Low density mixed with hyper-density (hemorrhagic infarct)

 Identify mass-like lesions

 ABBBC (Air-Blood-Bone-Brain-CSF) mnemonic [30]