Computed tomography and otosclerosis: a practical method to correlate the sites affected to hearing loss

Utility of machine learning for identifying stapes fixation on ultra-high-resolution CT

PURPOSE

Imaging diagnosis of stapes fixation (SF) is challenging owing to a lack of definite evidence. We developed a comprehensive machine learning (ML) model to identify SF on ultra-high-resolution CT.

MATERIALS AND METHODS

We retrospectively enrolled 109 participants (143 ears) and divided them into the training set (115 ears) and test set (28 ears). Stapes mobility (SF or non-SF) was determined by surgical inspection. In the ML analysis, rectangular regions of interest were placed on consecutive axial slices in the training set. Radiomic features were extracted and fed into the training session. The test set was analyzed using 7 ML models (support vector machine, k nearest neighbor, decision tree, random forest, extra trees, eXtreme Gradient Boosting, and Light Gradient Boosting Machine) and by 2 dedicated neuroradiologists. Diagnostic performance (sensitivity, specificity and accuracy, with surgical findings as the reference) was compared between the radiologists and the optimal ML model by using the McNemar test.

RESULTS

The mean age of the participants was 42.3 ± 17.5 years. The Light Gradient Boosting Machine (LightGBM) model showed the highest sensitivity (0.83), specificity (0.81), accuracy (0.82) and area under the curve (0.88) for detecting SF among the 7 ML models. The neuroradiologists achieved good sensitivities (0.75 and 0.67), moderate-to-good specificities (0.63 and 0.56) and good accuracies (0.68 and 0.61). This model showed no statistical differences with the neuroradiologists (P values 0.289-1.000).

CONCLUSIONS

Compared to the neuroradiologists, the LightGBM model achieved competitive diagnostic performance in identifying SF, and has the potential to be a supportive tool in clinical practice.

Do CT values change over time and correlate with hearing in the non-surgical ears of otosclerosis patients?

BACKGROUND

High-resolution computed tomography (HRCT) is often used to diagnose otosclerosis.

AIMS/OBJECTIVES

To investigate whether CT values change over time and correlate with hearing in the non-surgical ears of otosclerosis patients.

MATERIALS AND METHODS

32 patients with bilateral otosclerosis who had undergone unilateral stapedectomy were enrolled in the study. HRCT examination and pure tone audiometry were performed before and after the surgery. CT values of different regions of interest (ROIs) were measured manually and the data were collected for analysis.

RESULTS

The CT value of anterior to the inner auditory meatus (AIAM) decreased by 88.5 HU (p < .05), and the changes in CT values in other ROIs showed no statistical difference. Regarding hearing, the value of air bone gap (ABG) increased by 3.6 dB (p = .020), and the average hearing deterioration rate of ABG was 3.1 dB/year. The CT value of the mid-point of the stapes footplate (MPSF) showed a certain correlation with the change of ABG (p < .05).

CONCLUSIONS AND SIGNIFICANCE

The CT value of AIAM may change over time. The overall hearing of non-surgical ears in otosclerosis patients shows a deteriorating trend. Moreover, the changes in the CT value of MPSF may be related to the hearing, which needs further research.

Stability of computed tomography densitometry in patients with otosclerosis:a two-year follow-up

Objectives

To quantify the progression of otosclerosis in the unoperated ear between two stapedotomy procedures for patients with bilateral otosclerosis which can help to determine whether a HRCT scan should be re-performed before the second surgery for patients who already received HRCT imaging before the initial surgery.

Methods

35 patients who underwent bilateral stapedotomy were included. Two rounds of HRCT examination and audiometry were performed at the time of the first surgery and second surgery on the ear that was not operated on during the initial surgery. The relationship between the changes in HRCT densitometry and audiometry over time was analyzed.

Results

The second round of HRCT did not add significant information about the changes to the otosclerosis lesions in either the imaging diagnosis or the HRCT density values except for small changes in the HRCT densitometry readings at the area anterior to the inner auditory (P = 0.01). While the changes in HRCT manifestation are small, changes near the fissula ante fenestram (FAF) were still positively correlated with the air bone gap (ABG) of patients (p = 0.031, r = 0.388).

Conclusions

The progression of lesions in otosclerosis is slow resulting in small and insignificant changes to the HRCT features. Therefore, a repeat HRCT evaluations prior to surgery is not necessary for patients who have had a previous HRCT evaluation within 2 years of the operation. The small changes in HRCT manifestation near the FAF were still correlated with negative effects on the ABG which could cause worsened hearing thresholds over this timeframe.

"Third Window" and "Single Window" Effects Impede Surgical Success: Analysis of Retrofenestral Otosclerosis Involving the Internal Auditory Canal or Round Window

Background and Objectives: We aimed to identify prognostic computed tomography (CT) findings in retrofenestral otosclerosis, with particular attention paid to the role of otosclerotic lesion area in predicting post-stapedotomy outcome. Materials and Methods: We included 17 subjects (23 ears) with retrofenestral otosclerosis who underwent stapedotomy. On preoperative CT, the presence of cavitating lesion and involvement of various subsites (cochlea, round window [RW], vestibule, and semicircular canal) were assessed. Pre- and post-stapedotomy audiometric results were compared according to the CT findings. The surgical outcomes were analyzed using logistic regression with Firth correction. Results: Cavitating lesions were present in 15 of 23 ears (65.2%). Involvement of the RW was the strongest predictor of unsuccessful surgical outcome, followed by involvement of the internal auditory canal (IAC) and the cochlea. Conclusions: RW and IAC involvement in retrofenestral otosclerosis were shown to predict unsuccessful outcomes. While a “third window” effect caused by extension of a cavitating lesion into the IAC may dissipate sound energy and thus serve as a barrier to desirable postoperative audiological outcome, a “single window” effect due to an extension of retrofenestral otosclerosis into the RW may preclude a good surgical outcome, even after successful stapedotomy, due to less compressible cochlear fluid and thus decreased linear movement of the piston.

Otosclerosis: anatomical distribution of otosclerotic loci analyzed by high-resolution computed tomography

PURPOSE

To clarify the anatomical distribution of otosclerotic loci in otosclerosis.

METHODS

Ninety-five patients with surgically confirmed uni- or bilateral otosclerosis were enrolled into the study. Hypodense areas observed in the otic capsule by high-resolution computed tomography (HRCT) were defined as otosclerotic loci. The location and number of lesions were examined, and the probability of lesion overlap and correlation with age/hearing parameters (air and bone conduction threshold, air-bone gaps) were tested.

RESULTS

Otosclerotic loci were confirmed by HRCT in 77 out of 115 operated ears. The three commonly affected sites were the anterior part of the oval window (ant-OW), anterior part of the internal auditory canal (ant-IAC), and pericochlear area (PCochA), with lesions detected in 96.1%, 46.8%, and 26.0% of ears, respectively. Only the ant-OW area was affected in 48.1% of the ears; the ant-IAC in 3.9%; and PCochA in none with significant differences (p < 0.01). The ant-OW lesions preferentially overlapped with ant-IAC (44.6%) than PCochA lesions (27.0%) (p < 0.05). Among double sites diseases, triple sites diseases occurred more commonly in the ant-OW + PCochA group (80%) than ant-OW + ant-IAC group (48.5%) (p < 0.05). There was no correlation between a number of lesions and age/hearing parameters.

CONCLUSIONS

Based on the probability of lesion overlap, otosclerotic lesions may initiate at ant-OW followed by ant-IAC and later PCochA. Although the number of lesions showed no immediate correlation with hearing level or age, anatomical stage of the disease estimated by the location and the number of otosclerotic loci could be useful in predicting the future hearing status.

Impact of Imaging in Management of Otosclerosis

The use of imaging in otosclerosis for diagnosis, preoperative assessment, and follow-up has the potential to give the clinician an additional tier of patient evaluation and validation of diagnosis. Before stapes surgery, imaging may help avoid unnecessary middle ear explorations in nonotosclerotic cases, prevent potential complications, and assist in appropriate patient counseling regarding management expectations. Postoperatively, following unsuccessful air-bone gap closure in stapes surgery or conductive hearing deterioration following initial successful closure of the air bone gap, imaging can be used to determine the prosthesis position in the middle ear.

Cavitary Plaques in Otospongiosis: CT Findings and Clinical Implications

BACKGROUND AND PURPOSE

Cavitary plaques have been reported as a manifestation of otospongiosis. They have been related to third window manifestations, complications during cochlear implantation, and sensorineural hearing loss. However, their etiology and clinical implications are not entirely understood. Our purpose was to determine the prevalence, imaging findings, and clinical implications of cavitary plaques in otospongiosis.

MATERIALS AND METHODS

We identified patients with otospongiosis at a tertiary care academic medical center from January 2012 to April 2017. Cross-sectional CT images and clinical records of 47 patients (89 temporal bones) were evaluated for the presence, location, and imaging features of cavitary and noncavitary otospongiotic plaques, as well as clinical symptoms and complications in those who underwent cochlear implantation.

RESULTS

Noncavitary otospongiotic plaques were present in 86 (97%) temporal bones and cavitary plaques in 30 (35%). Cavitary plaques predominated with increasing age (mean age, 59 years; P = .058), mostly involving the anteroinferior wall of the internal auditory canal (P = .003), and their presence was not associated with a higher grade of otospongiosis by imaging (P = .664) or with a specific type of hearing loss (P = .365). No patients with cavitary plaques had third window manifestations, and those with a history of cochlear implantation (n = 6) did not have complications during the procedure.

CONCLUSIONS

Cavitary plaques occurred in one-third of patients with otospongiosis. Typically, they occurred in the anteroinferior wall of the internal auditory canal. There was no correlation with the degree of otospongiosis, type of hearing loss, or surgical complications. Cavitary plaques tended to present in older patients.

[The application of stapedoplasty for the treatment of hearing loss in the patients suffering from obliterative otosclerosis]

This article presents the results of analysis of the data obtained during the examination and the surgical treatment of the patients presenting with the obliterative form of otosclerosis and suffering from hearing impairment with special reference to the intraoperative findings, technical aspects of stapedoplasty, and its effectiveness. A total of 14 patients (17 ears) were recruited for the participation in the present study including 10 women at the mean age of 38.8±6.2 years and 4 men (mean age 44.8±3.9 years). The duration of the hearing loss in the period preceding the surgical treatment in 7 (50%) patients was more than 8 years. According to the results of tonal threshold audiometry (TTA), the mean bone conduction (BC) threshold for conductive hearing loss in the frequency range from 0.5 to 4.0 kHz was 24.9±8.1 dB with the mean bone air gap (BAG) equaling 38±5.1 dB. Computed tomography (CT) of the temporal bones revealed grade 1 obliterative otosclerosis in 4 patients, grade II of the same condition in 6 patients, and grade III in 7 ones. These findings were confirmed intraoperatively. In 15 cases, stapedostomy was carried out with the use of the non-contact CO2 laser-based system, in the remaining cases a microdrill was employed. Five patients underwent laser-assisted piston stapedoplasty while in 11 others the stapes prosthesis was placed on the autovein. One patient was treated by the same method with the use of the autocartilaginous prosthesis. The functionally acceptable results within 1 year after the surgical intervention were obtained in all the treated patients with the mean bone air gap equaling 13.2±3.4 dB. The best outcome (the reduction of the BC threshold and BAG by 7 dB and 25.9 db on the average respectively within 1 year after surgery was achieved in the patients with grade III obliterative otosclerosis.

A Systematic Review of the Diagnostic Value of CT Imaging in Diagnosing Otosclerosis

OBJECTIVE

To evaluate the diagnostic value of computed tomography (CT) in detecting otosclerosis in patients with conductive hearing loss and a clinical suspicion of otosclerosis.

DATA SOURCES

PubMed, Embase, and the Cochrane Library.

STUDY SELECTION

A systematic search was conducted. Studies reporting original study data were included.

DATA EXTRACTION

Relevance and risk of bias of the selected articles were assessed. Studies with low relevance, high risk of bias, or both were excluded. Prevalences, sensitivities, specificities, and post-test probabilities were extracted from the included articles.

DATA SYNTHESIS

Seven studies characterized by a moderate to high relevance and moderate to low risk of bias were included for data extraction. The prevalence of otosclerosis was high (up to 100%) in the majority of the included studies. In those studies with a high prevalence of disease, both positive and negative post-test probabilities were (relatively) high: 99% and between 51% and 67% respectively. In one study with a low prevalence of disease (9%), both positive and negative post-test probabilities were low (23% and 3% respectively). Overall, reported sensitivities ranged between 60% and 95%.

CONCLUSION

Preoperative CT has little to add in establishing otosclerosis and may not be necessary to confirm the diagnosis. We would recommend reserving CT for those patients with suspected additional abnormalities, for specific preoperative planning, or out of legal necessity.

Diagnostic efficacy and therapeutic impact of computed tomography in the evaluation of clinically suspected otosclerosis

OBJECTIVE

To assess the diagnostic efficacy and therapeutic impact of CT in evaluating patients with clinically suspected otosclerosis.

METHODS

CT scans performed over a 5-year period for clinically suspected otosclerosis were retrospectively reviewed. CT diagnoses were correlated with subsequent surgical management. For otosclerosis positive cases, clinically significant extensions of otosclerosis were correlated with audiometry and the diagnosis was correlated with surgical findings.

RESULTS

Of 259 CT studies, 46 % of patients were positive, 49 % negative and 5 % equivocal for otosclerosis. A relevant alternative CT diagnosis was evident in 33 % of the negative studies. One targeted surgery was performed for every four CT studies. CT outcome influenced the decision to perform stapedectomy in 41 % CT-positive versus 4 % CT-negative patients. CT-positive ears for otosclerosis could not be predicted from baseline clinical or audiometric criteria. Those with endosteal extension demonstrated lower bone conduction thresholds presurgically. The positive predictive value of CT diagnosis of otosclerosis was 100 %.

CONCLUSIONS

CT demonstrated a high rate of clinically relevant diagnoses in both CT-positive and -negative for otosclerosis patients, and this frequently influenced surgical management. CT also added value by demonstrating relevant extensions of the otosclerotic foci, some of which were predictive of audiometric parameters.

KEY POINTS

• CT demonstrates a high rate of alternative diagnoses in suspected otosclerosis, 1:3. • CT results in a high rate of targeted surgery in suspected otosclerosis, 1:4. • CT prevents exploratory surgery in suspected otosclerosis. • Endosteal extension of otosclerosis is predictive of lower bone conduction tresholds presurgically. • The PPV of CT diagnosis of otosclerosis was 100 %.

Audiometric Results after Stapedotomy Operations in Patients with Otosclerosis and Preoperative Small Air-Bone Gaps

Objectives: The efficacy of stapedotomies performed on patients with small air-bone gaps (<25 dB) was compared with the efficacy of the operation in patients who had otosclerosis with high air-bone gaps (≥25 dB). Methods: This retrospective study evaluates the short-term postoperative air and bone conduction thresholds and air-bone gaps after 182 CO2 laser stapedotomies. Results: A significantly smaller air-bone gap and lower air conduction thresholds after surgery were observed in the group of patients who underwent surgery with preoperative air-bone gaps of less than 25 dB. Bone conduction thresholds improve in the group with small air-bone gaps after surgery. Conclusions: The results after stapedotomies are good even if the preoperative air-bone gap is small and the overall risk of hearing deterioration due to stapes surgery remains low.

The role of imaging in the diagnosis and management of otosclerosis

OBJECTIVE

To examine the evidence for the role of radiologic imaging in the diagnosis and management of otosclerosis.

DATA SOURCES

A review of contemporary (1990 to present) English medical literature via MedLine using the terms imaging, otosclerosis, otospongiosis, stapes surgery, computed tomography, magnetic resonance, CT, and MRI was performed.

STUDY SELECTION

Abstracts were reviewed independently by 2 authors and relevant articles were then evaluated. Exclusion criteria included editorials, non-English language, comments, and letters.

DATA EXTRACTION

Level of evidence was assigned in accordance with the Oxford Centre for Evidence-based Medicine guidance (Levels I-V).

RESULTS

Thirty-seven articles met the inclusion criteria, of which, 11 were of Level III, 22 of Level IV, and 4 of level V evidence. High-resolution computed tomography (CT) of the temporal bones is the imaging technique of choice in the diagnosis of otosclerosis with newer multidetector scanners demonstrating a sensitivity and specificity in excess of 90%. There is Level III evidence that CT densitometry and extent of disease on CT correlates with hearing thresholds. Extensive and multifocal disease on CT has a poorer prognosis (Level III/IV). The potential use of CT in staging classifications, surgical planning, predicting surgical outcomes and risk of complications has also been described and evaluated.

CONCLUSION

This systematic review indicates that imaging has a useful role in both the diagnosis and management of otosclerosis, supported principally by Level III/IV evidence.

The radiological diagnosis of fenestral otosclerosis: the utility of histogram analysis using multidetector row CT

Bone density measurements using high-resolution CT have been reported to be useful to diagnose fenestral otosclerosis. However, small region of interest (ROI) chosen by less-experienced radiologists may result in false-negative findings. Semi-automatic analysis such as CT histogram analysis may offer improved assessment. The aim of this study was to evaluate the utility of CT histogram analysis in diagnosing fenestral otosclerosis. Temporal bone CT of consecutive patients with otosclerosis and normal controls was retrospectively analyzed. The control group consisted of the normal-hearing contralateral ears of patients with otitis media, cholesteatoma, trauma, facial nerve palsy, or tinnitus. All CT images were obtained using a 64-detector-row CT scanner with 0.5-mm collimation. AROI encompassing 10 × 10 pixels was placed in the bony labyrinth located anterior to the oval window. The mean CT value, variance and entropy were compared between otosclerosis patients and normal controls using Student's t test. The number of pixels below mean minus SD in the control (%Lowcont) and total subjects (%Lowtotal) were also compared. In addition, the area under the receiver operating characteristic curves (AUC) value for the discrimination between otosclerosis patients and normal controls was calculated. 51 temporal bones of 38 patients with otosclerosis and 30 temporal bones of 30 control subjects were included. The mean CT value was significantly lower in otosclerosis cases than in normal controls (p < 0.01). In addition, variance, entropy, %Lowcont and %Lowtotal were significantly higher in otosclerosis cases than in normal controls (p < 0.01, respectively). The AUC values for the mean CT value, %Lowcont and %Lowtotal were 0.751, 0.760 and 0.765, respectively. In conclusion, our results demonstrated that histogram analysis of CT image may be of clinical value in diagnosing otosclerosis.

Computed tomography features of luetic osteitis (otosyphilis) of the temporal bone

Objective:

We report a missed case of otosyphilis presenting as otic capsule lucencies on temporal bone computed tomography.

Methods:

A 58-year-old woman presented with a 15-year history of bilateral, mixed hearing loss together with otic capsule lucencies, subsequently confirmed as otosyphilis. A literature review of otosyphilis was undertaken based on a PubMed search of studies published between 1988 and 2012, using the key words ‘otosyphilis’, ‘otodystrophy’, ‘otic capsule lucencies’ and ‘luetic osteitis’.

Results and conclusion:

Although rare, otosyphilis is important to recognise as it is one of the few treatable causes of deafness when diagnosed early. The differentiating computed tomography features of luetic osteitis (otosyphilis) of the temporal bone have only rarely been described. We emphasise how these imaging features can be used to distinguish the rare but treatable condition of luetic osteitis from other, more common conditions with similar imaging findings.

Tomographic diagnosis and relevant aspects of otosclerosis

A literature review and pictorial essay were developed to discuss the importance of knowing the main findings and locations of otosclerosis at multidetector computed tomography (MDCT). The authors performed a retrospective review of cases of otosclerosis diagnosed in their institution by means of high resolution multidetector computed tomography. Otosclerosis corresponds to otic capsule dysplasia characterized by metabolic derangement of its endochondral layer. Such condition constitutes a relevant cause of sensorineural hearing loss, affecting about 7% to 10% of the general population. The diagnosis is usually clinical, but imaging methods play a significant role in the anatomical detailing, differential diagnosis, surgical planning and evaluation of postoperative complications. Among such methods, the relevance of MDCT is highlighted. Radiologists should be familiar with the MDCT findings of otosclerosis, as well as with the temporal bone anatomy to assist in the appropriate clinical management of this disease.

Cochlear implantation outcomes in patients with far advanced otosclerosis

OBJECTIVES

To compare hearing outcomes in patients with far advanced otosclerosis (FAO) undergoing cochlear implantation to an age-matched group of controls, to describe the effects of cochlear ossification on hearing, and to review the adverse effects of implantation in patients with FAO.

HYPOTHESIS

Hearing performance in patients with FAO after cochlear implantation is comparable to similarly treated postlingually deafened adults without FAO. Ossification or retrofenestral otosclerosis does not predict poor hearing outcomes. Modiolar-hugging technology reduces postoperative facial nerve stimulation.

STUDY DESIGN

Retrospective chart review.

SETTING

Academic neurotologic tertiary referral center.

PATIENTS

Thirty patients with FAO, who metaudiological criteria for cochlear implantation, were compared to 30 age-matched controls, postlingually deafened by non-otosclerotic causes.

MAIN OUTCOME MEASURES

Audiometric pre- and postoperative speech reception threshold, word, and sentence scores were analyzed. The presence of retrofenestral findings on computed tomography or intraoperative cochlear ossification were noted.

RESULTS

In the FAO group, radiographic abnormalities were noted in 26.4% of patients. Intraoperative ossification requiring drillout was seen in 29.4% of patients. None developed postoperative facial nerve stimulation. There was no difference between the FAO and control groups in the mean short-term and long-term postoperative speech reception threshold, word, and sentence scores (P = .77). The presence of radiographic abnormalities did not predict hearing outcome. Intraoperative cochlear ossification was not associated with worse short-term word and sentence scores (P = .58 and 0.79, respectively), and for the long-term hearing outcome (P = .24).

CONCLUSIONS

In patients with FAO, effective and safe hearing rehabilitation can be accomplished with cochlear implantation.