Table 3: Image severity index score [3].


Number (single, multilocular, or attached to each other like a bunch of grapes = 1; score increased for every additional abscess)

Location (superficial: cerebral, cerebellar hemispheres; deep: basal ganglia, thalamus, corpus callosum, brain stem, vermis, and within ventricles; extensive or combined: both superficial and deep)

Diameter (large diameter of abscess in transverse plane on CT and MRI; largest diameter of multilocular abscess is the largest diameter of the abscess taken as a whole)
 <2 cm1
 2–4 cm2
 >4 cm3

Perilesional edema (surrounding edema observed as high signal intensity on T2 weighted MRI image or hypodensity on CT image. For multiple abscesses, highest for edema was used)
 Minimal (maximum thickness < radius of abscess)1
 Moderate (maximum thickness between the radius and diameter of abscess)2
 Large (maximum thickness > diameter of abscess)3

Midline shift (in mm)
 Mild (<5 mm)1
 Moderate (5–10 mm)2
 Severe (>10 mm)3