OBJECTIVETo investigate the methods of preoperative diagnosis and differentiation of different pathological tissue in middle ear and mastoid.

METHODSThe temporal bone lamellar CT findings in 106 patients with chronic suppurative otitis media (including cholesteatoma) were retrospectively analyzed. The CT value of pathological tissue were measured for 183 times and were compared with the surgical findings and postoperative pathological findings to definitude the CT value range of different pathological tissue. Sixty patients taken from 106 patients at random were analyzed and made the diagnosis again by the same doctor team according to the CT value of the different pathological tissue and surrounding histoclasia resulted by pathological tissue. The diagnose accordance rate was compared with the routine diagnose report from radiology department. The predetective diagnosis was made in 10 patients with chronic suppurative otitis media according to clinical manifestation (pathological changes of tympanic membrane, nature of otorrhea, character of hearing), temporal bone lamellar CT finding (CT value of pathological tissue, surrounding histoclasia) to validate the value of this study for preoperative diagnosis and differentiation of different pathological tissue in middle ear and mastoid.

RESULTSThe CT value of cholesteatoma, granulation tissue, cholesteatoma combined with granulation tissue, effusion, calcified tissue, thickened and polypoid membrane was respectively (46.6 +/- 10.3) Hu, (26.6 +/-7.4) Hu, (42.1 +/- 11.4) Hu, (- 24.6 +/- 9.2) Hu, (223.6 +/- 63.7) Hu, (23.8 +/- 8.5) Hu. The diagnose accordance rate in 60 patients who were analyzed and made diagnosis again according to the CT value of the different pathological tissue and surrounding histoclasia resulted by pathological tissue raised from 68. 3% to 81.7% ( P < 0.05) . The predetective diagnose accordance rate reached at 90% according to clinical manifestation, temporal bone lamellar CT.

CONCLUSIONSIt was not reliable to diagnose and differentially diagnose different pathological tissue in middle ear and mastoid only by the CT value, however, the CT value could still be considered to be a very significant information. The accurate rates of diagnosis and differentiation of different pathological tissue in middle ear and mastoid obviously raised by synthetically analyzing various kinds of pathological tissues in middle ear and mastoid according to clinical manifestation, temporal bone lamellar CT finding.