ROLE OF HIGH-RESOLUTION CT (HRCT) IN THE DIAGNOSIS OF CHRONIC OTITIS MEDIA AND CHOLESTEATOMA

Chronic Otitis Media (COM) is a major issue in world health, especially in developing countries, where it is among the major causes of avoidable hearing loss. The disease falls broadly into mucosal and squamous forms; the latter is defined as having a cholesteatoma, a non-neoplastic, keratinising squamous epithelial lesion, which has distinctive bone-eroding ability [1]. The clinical impact of cholesteatoma is the capability to cause an enzymatic and pressure-based destruction of the surrounding temporal bone, which causes life-altering complications, including permanent hearing loss, facial nerve paralysis, labyrinthine fistula and even intracranial infections such as meningitis or brain abscess [2]. Historically, treatment of COM was mainly by touch, using the otoscopy and tuning fork tests. But the complicated structure of the temporal bone, the labyrinth of air cells, the narrow bony plates and other vital neurovascular processes tend to conceal the real size of the disease with the naked eye [3]. This is where the High-Resolution Computed Tomography (HRCT) has transformed otology [4]. HRCT offers a higher spatial resolution, which has images on thin sections (0.5mm to 1mm) to enable visualisation of the ossicular chain, the scutum, the tegmen tympani, and the fallopian canal with accuracy [5]. The main dilemma facing the present-day otologist is not only the diagnosis, but the surgical preparation. HRCT serves as an anatomic road mapping approach, warning the surgeon of anatomic differences such as a low-lying dura or anteverted sigmoid sinus, which may cause iatrogenic harm when unrecognized [6]. Although HRCT is very sensitive to bone erosion, it suffers from the inability to differentiate cholesteatoma, granulation tissue, and inflammatory fluid, since all of them are presented as soft tissue densities [7]. Nevertheless, its value in diagnosing the cases of subclinical complications before their emergence in the form of an emergency renders it an invaluable part of the diagnostic workup. Radiologically comparing the findings with the reality on the ground during surgery, clinicians can provide resourceful counseling to the patients towards the anticipation of the results and selection of canal-wall-up or canal-wall-down surgery [8,9].

Study Objectives

H0 No notable differences exist in the accuracy of HRCT in diagnosing cholesteatoma and ossicular erosion. To compare the preoperative HRCT results to intraoperative results in 100 cases of COM

Study Design & Setting

It was a prospective study conducted at Department of ENT, Khyber Medical College / Khyber Teaching Hospital, Peshawar, from January 2024 to January  2025.12 months at a tertiary care otorhinolaryngology department. It involved 100 patients who were to be operated on based on clinical symptoms using the mastoid procedure.

Participants

The sample consisted of 100 individuals aged 10-65 years who came with persistent ear discharge, hearing loss or vertigo. The subjects were chosen irrespective of sex, as long as they had clinical evidence of COM (squamosal or active mucosal type) and fit to be subjected to general anaesthesia.

Sample Size Calculation

The power analysis was calculated on an expected sensitivity of HRCT of 90 per cent in the detection of cholesteatoma according to the literature on the topic, as applicable to the sample size of 100 patients. A 95% confidence and a 10 percent margin of error were used to make sure that there is statistical significance.

Inclusion Criteria

 Clinically, patients who have had a retraction pocket of the attic, or cholesteatoma, are exposed on otoscopy.

Exclusion Criteria

 Individuals who have undergone ear surgery (recurrent cases), acute otitis media or patients who have contraindications to CT scanning (e.g. pregnancy).

Diagnostic Strategy and Management Strategy.

All the patients received HRCT of the temporal bone axially and coronally. A senior radiologist registered findings. Then, the patients had a tympanomastoidectomy, during which a surgeon (blinded to certain CT measures) registered the actual findings of the anatomy.

Statistical Analysis

The analysis of data was done using SPSS version 25.0. Demographic information was summarised using descriptive statistics. The Chi-square test and Cohen's kappa were employed to establish the relationship and agreement between HRCT and surgical results. P < 0.05 was regarded as statistically significant.

Ethical Approval

The study cohort consisted of 100 patients with a mean age of 34.5 years ( SD \pm 12.2 ). The most common presenting symptom was otorrhea ( 92\% ), followed by hearing loss ( 85\% ). Statistical analysis revealed a highly significant correlation between HRCT findings and intraoperative observations ( P < 0.001 ).HRCT correctly identified cholesteatoma in 92 out of 100 cases, yielding a sensitivity of  92\% . For ossicular integrity, HRCT was most accurate in detecting incus erosion ( 88\%  accuracy). However, it was less reliable for identifying stapes superstructure erosion due to its minute size. Regarding bony complications, HRCT showed high specificity ( 95\% ) for tegmen erosion and sigmoid plate dehiscence. Notably, in 15% of cases, the soft tissue mass seen on CT was found to be granulation tissue rather than cholesteatoma during surgery, indicating that while CT is excellent for seeing "where" the disease is, it occasionally overestimates "what" the disease is.

Intervention Outcome

Preoperative HRCT usage was important to the surgical approach in  22\%  of cases; the presence of a low-lying dura or an aberrant facial nerve. Successful surgery was carried out on all 100 patients without any serious iatrogenic complications, which proves that HRCT is effective in improving the safety and accuracy of surgery.

Table 1: Demographic Profile of the Study Population ( N=100 )

This table describes the age and gender distribution of the participants, showing a mean age of 34.5 years and a slight male predominance.

Table 2: Comparison of HRCT and Intraoperative Findings for Cholesteatoma

Comparison of soft tissue density on HRCT versus the actual presence of cholesteatoma during surgery. The high p-value correlation indicates HRCT's strong diagnostic reliability.

Table 3: Diagnostic Accuracy of HRCT in Detecting Ossicular Erosion

This table evaluates how well HRCT identifies damage to the three middle ear bones compared to what was found during the mastoidectomy.

Table 4: Correlation of HRCT for Bony Complications and Dehiscence

This table shows the effectiveness of HRCT in identifying erosion of critical bony barriers, which is vital for preventing surgical complications.

The outcome of the study highlights the critical significance of High-Resolution Computed Tomography (HRCT) as a preoperative map of the surgery on Chronic Otitis Media (COM) and cholesteatoma. Through the ability to offer thin-section images, the HRCT can be used to perform a careful examination of the middle ear anatomy, which is not easily viewed during a clinical examination [10,11]. The results of our study, which reveal the existence of the cholesteatoma at 92 per cent sensitivity, are in agreement with the current studies. In a study by Saeed et al. (2025) on 147 patients, the sensitivity was reported as  90.2\%  and specificity as  90.9\% , which confirms the reliability of HRCT in high-prevalence areas [11,12]. On the same note, Gupta et al. (2025) showed a sensitivity of  91.9 percent, though they had lower specificity (40 per cent) because of the nature of the HRCT, as it is more difficult to distinguish between cholesteatoma and granulation tissue, whereas it was lower in our cases (18 per cent) [13,14]. The incus was the most eroded ossicle (84 per cent of incus intraoperative, 91 per cent on HRCT), as observed in this study. Stefanescu et al. (2025) found the incus to have the highest correlation, which explains their systematic review and the choice of the incus as the most reliable ossicle that preoperative imaging predictively indicated (k = 0.77). Nevertheless, this sensitivity was lower in our study with stapes superstructure (68.4 per cent) as compared to Gajjar et al. who showed that it is due to the minute size of stapes and the stapes masking effect of surrounding inflammatory debris or soft tissue attenuation content (STAC) [15,16]. We have a perfect or near-perfect correlation of the sigmoid plate erosion (with  P < 0.001), which is in agreement with Zaman et al, seeing as they did the same parameter with 100 per cent accuracy. On the other hand, we were also less sensitive to the facial canal dehiscence (65 per cent) [17,18]. This is a common phenomenon in the recent literature; as reported by Rajashekhar et al. (2025), the facial canal showed moderate agreement only (k = 0.54), and the suggestion is that a negative CT scan cannot be used to induce complacency about surgery around the nerve [19,20]. Although HRCT is better in the imaging of bony detail, its main drawback is that it is not a soft-tissue-specific method. According to the findings of study by Gupta et al. and Rajashekhar et al, although HRCT is a vital component of mapping, Diffusion-Weighted MRI (DWI) is to be regarded as the second gold standard in the process of differentiating between recurrent cholesteatoma and postoperative scarring or granulation [21,22].

Limitations

The major drawback of HRCT is that it can not clearly distinguish between cholesteatoma, granulation tissue and inflammatory fluid because they all look like soft-tissue densities. Also, HRCT is less sensitive to finding small cases of facial nerve dehiscence and stapes superstructure erosion, as the size of those structures is small and the volume is average.

 HRCT of the temporal bone is a mandatory preoperative roadmap to the treatment of Chronic Otitis Media. Although it may not be able to accurately identify particular tissues, it has a high level of accuracy at determining ossicular destruction and bony dehiscence, which is statistically significant (P = 0.05). It is still necessary to improve the safety of surgery and to avoid iatrogenic complications.

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