Hinchey classification of acute diverticulitis

The original Hinchey classification was based on perioperative surgical finding. It has been later modified by Sher et al.:

Modified Hinchey classification (Sher et al., 1997):

Stage Description
I Pericolic abscess
IIa Distant abscess amendable to percutaneous drainage
IIb Complex abscess associated with fistula
III Generalized purulent peritonitis
IV Fecal peritonitis

Several modifications have been proposed to adapt Hinchey classification for CT findings, Sartelli et al. discriminated between uncomplicated disease and complicated disease stage Ia to 4
Sartelli et al.

Sartelli classification (Sartelli et al., 2015):

Stage Description
Uncomplicated disease
  Diverticula, thickening of the wall, increased density of the pericolic fat
Complicated disease
Ia Pericolic air bubbles or little pericolic fluid without abscess
Ib Abscess ≤4cm
IIa Abscess >4cm
IIb Distant air (>5cm from inflamed bowel segment)
III Diffuse fluid without distant free air (no hole in colon)
IV Diffuse fluid with distant free air (persistent hole in colon)

References
Hinchey EJ, Schaal PG, Richards GK. Treatment of perforated diverticular disease of the colon. Adv Surg. 1978;12:85-109.
Sher ME, Agachan F, Bortul M. Laparoscopic surgery for diverticulitis. Surg Endosc. 1997;11:264–267.
Sartelli M, et al: A proposal for a CT driven classification of left colon acute diverticulitis. World J Emerg Surg 2015; 10: 3.