A systematic approach to interpretation of computed tomography scans prior to surgery of middle ear cholesteatoma

A 3D and Explainable Artificial Intelligence Model for Evaluation of Chronic Otitis Media Based on Temporal Bone Computed Tomography: Model Development, Validation, and Clinical Application

BACKGROUND

Temporal bone computed tomography (CT) helps diagnose chronic otitis media (COM). However, its interpretation requires training and expertise. Artificial intelligence (AI) can help clinicians evaluate COM through CT scans, but existing models lack transparency and may not fully leverage multidimensional diagnostic information.

OBJECTIVE

We aimed to develop an explainable AI system based on 3D convolutional neural networks (CNNs) for automatic CT-based evaluation of COM.

METHODS

Temporal bone CT scans were retrospectively obtained from patients operated for COM between December 2015 and July 2021 at 2 independent institutes. A region of interest encompassing the middle ear was automatically segmented, and 3D CNNs were subsequently trained to identify pathological ears and cholesteatoma. An ablation study was performed to refine model architecture. Benchmark tests were conducted against a baseline 2D model and 7 clinical experts. Model performance was measured through cross-validation and external validation. Heat maps, generated using Gradient-Weighted Class Activation Mapping, were used to highlight critical decision-making regions. Finally, the AI system was assessed with a prospective cohort to aid clinicians in preoperative COM assessment.

RESULTS

Internal and external data sets contained 1661 and 108 patients (3153 and 211 eligible ears), respectively. The 3D model exhibited decent performance with mean areas under the receiver operating characteristic curves of 0.96 (SD 0.01) and 0.93 (SD 0.01), and mean accuracies of 0.878 (SD 0.017) and 0.843 (SD 0.015), respectively, for detecting pathological ears on the 2 data sets. Similar outcomes were observed for cholesteatoma identification (mean area under the receiver operating characteristic curve 0.85, SD 0.03 and 0.83, SD 0.05; mean accuracies 0.783, SD 0.04 and 0.813, SD 0.033, respectively). The proposed 3D model achieved a commendable balance between performance and network size relative to alternative models. It significantly outperformed the 2D approach in detecting COM (P≤.05) and exhibited a substantial gain in identifying cholesteatoma (P<.001). The model also demonstrated superior diagnostic capabilities over resident fellows and the attending otologist (P<.05), rivaling all senior clinicians in both tasks. The generated heat maps properly highlighted the middle ear and mastoid regions, aligning with human knowledge in interpreting temporal bone CT. The resulting AI system achieved an accuracy of 81.8% in generating preoperative diagnoses for 121 patients and contributed to clinical decision-making in 90.1% cases.

CONCLUSIONS

We present a 3D CNN model trained to detect pathological changes and identify cholesteatoma via temporal bone CT scans. In both tasks, this model significantly outperforms the baseline 2D approach, achieving levels comparable with or surpassing those of human experts. The model also exhibits decent generalizability and enhanced comprehensibility. This AI system facilitates automatic COM assessment and shows promising viability in real-world clinical settings. These findings underscore AI's potential as a valuable aid for clinicians in COM evaluation.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000036300; https://www.chictr.org.cn/showprojEN.html?proj=58685.

Evaluation of the Sigmoid Sinus Morphology by Cone Beam Computed Tomography; Touchstone of the Posterior Cranial Fossa

OBJECTIVE

In this study, we aimed to analyze the relationship of the sigmoid sinus (SS) with the external auditory canal, facial nerve, and mastoid cells from an anatomic point of view, to define the position of the SS during transmastoid, translabyrinthine, retrosigmoid (lateral suboccipital) approaches, in tympanomastoidectomy and posterior cranial fossa surgery.

METHODS

In this study, the morphologic structures associated with the sigmoid sinus were evaluated in cone beam computed tomography images taken between 2015 and 2022. The images of 68 men and 106 women, aged 18-65 years, obtained from the archive of Ankara University Faculty of Dentistry, Department of Oral and Maxillofacial Radiology were analyzed.

RESULTS

The most common SS pattern was type II, with a rate of 60.8% (n = 209); the second was type III, with 20.6% (n = 71); and the least common was type I, with 18.6% (n = 64). Although the distance between the horizontal line passing through the external auditory canal and facial nerve and the anterior contour of the SS was highest in type I (right, 7.26 ± 1.62; left, 7.44 ± 0.97), it was lowest in type III (right, 4.40 ± 1.50; left, 4.84 ± 1.16) (P < 0.05).

CONCLUSIONS

This study highlights the importance of the SS position in surgery, with special reference to otologic, neurotologic, and posterior cranial fossa surgery. To avoid intraoperative complications, each patient should be evaluated preoperatively by appropriate radiologic methods.

Role of High Resolution Computed Tomography of Temporal Bone in Patients with Cholesteatoma, in a Tertiary Care Health Center

The aim of this study is to evaluate the necessity of high resolution computed tomography (HRCT) temporal bone in patients with active squamosal chronic otitis media, by comparing the preoperative HRCT temporal bone findings with intra operative findings in a tertiary care health center where patient load is tremendous.This study was conducted in the department of otorhinolaryngology, over a period of two years from November 2017 to November 2019 in which 100 patients with active squamosal chronic otitis media diagnosed clinically were taken. All patients underwent preoperative HRCT temporal bone and subsequent tympanomastoidectomy.The results of HRCT temporal bone of all the patients were evaluated and correlated with intraoperative findings which revealed that HRCT is highly sensitive for detecting,soft tissue extension, tympanic membrane perforation, ossicular erosion, tegmen erosion, sigmoid sinus erosion, facial canal dehiscence and lateral semicircular canal fistula, which helps in guiding the surgical approach and treatment plan preoperatively.

Computed-Tomography-Structured Reporting in Middle Ear Opacification: Surgical Results and Clinical Considerations From a Large Retrospective Analysis

Purpose: The aim of the study is to compare the accuracy of unstructured preoperative Computed Tomography (CT) reports from non-tertiary diagnostic centers with intraoperative findings in a large cohort of patients with Chronic Otitis Media (COM) undergone surgery.

Methods: From 2012 to 2019, a total number of 301 patients were considered for our purposes. All patients with clinical evidence of COM had preoperative non-contrast high resolution CT scan of the temporal bone in non-tertiary diagnostic centers, performed within 3 months before surgery.

Results: The accuracy of CT reports was analyzed in terms of nature, anatomical site, disease extension, bony erosion, vascular structures abnormalities relevant to surgical planning, and Eustachian tube patency. Compared to post-surgical findings, CT reporting critical analysis revealed a tendency to overestimation of bony erosion, coupled to underestimated description of facial canal/lateral semi-circular canal, vascular structures, and Eustachian tube.

Conclusion: Discrepancies between CT reports and surgical findings in middle ear opacification can be at least in part due to limited expertise of general radiologists in ENT neuroimaging. To limit this lack of information and the limited accuracy of middle ear structures depiction, here we propose a structured checklist to adopt in the case of a temporal bone CT scan for COM, in order to optimize the communication with surgeons and provide all the crucial information for an accurate surgical planning.

Distribution of different morphological types of anterior epitympanic plate “cog” and Köerner’s septum in CT images of cholesteatomatous and non-cholesteatomatous CSOM: is it really significant?

Background

The anterior epitympanic plate (cog) and Köerner’s septum are gaining more importance since the introduction of transcanal mastoidectomy as these anatomical structures are serving landmarks for the attic. Moreover, different morphological types of cog and Köerner’s septum revealed embryological relation to the development of the isthmic membrane; the latter is linked to aeration of the attic and thus affects the pathological development of the cholesteatoma.

Results

A retrospective review of CT images of 86 patients proved by surgical biopsies revealed: 49 cholesteatomas and 37 non-cholesteatomatous CSOM. The type-I “cog” had a higher incidence (n = 40) and was statistically more prevalent in non-cholesteatomatous CSOM (n = 30, 81.1%). Type-II was the second commonest and was statistically more prevalent in cholesteatomatous CSOM (n = 22, 44.9%). Type-III was the third commonest, seen in (n = 18, 20.9%) and was statistically more prevalent in cholesteatomatous CSOM (n = 17, 34.7%). Köerner’s septum was more prevalent in non-cholesteatomatous CSOM (70.3%) with statistical significance (p value = 0.002).

Conclusions

The difference in the distribution of different morphological types of anterior epitympanic plate “cog,” as well as the difference in Köerner’s septum existence amongst cholesteatomatous and non-cholesteatomatous CSOM are suggested as risk factors for the development of cholesteatoma and may predict a cholesteatoma on CT images.

Sensitivity and Specificity of High-Resolution Computed Tomography (HRCT) of Temporal Bone in Diagnosing Cholesteatoma and Its Correlation with Intraoperative Findings

High resolution computed tomography (HRCT) of temporal bone helps in understanding the complex anatomy of temporal bone and in identifying disease in temporal bone. However, its role in diagnosing cholesteatoma and analyzing its extent and complications is not established unequivocally. Present study was undertaken to check sensitivity and specificity of HRCT in diagnosing cholesteatoma and assessing its extent and in identifying ossicular destruction and other complications. In this prospective study in 50 patients with clinical diagnosis of cholesteatoma, preoperative high-resolution temporal bone CT scans axial and coronal view were carried out and compared with intra-operative findings. Kappa statistics was used for radio-surgical correlation. Comparison of CT scan findings with intraoperative findings revealed perfect correlation for sigmoid plate erosion, mastoid cortex dehiscence and scutum erosion, strong correlation for erosion of malleus, posterior superior wall and peri labyrinthine cells, good for erosion of incus and stapes, labyrinthine fistula, tegmen erosion and extent of disease and moderate correlation for facial canal dehiscence. HRCT scan of the temporal bone is useful preoperative investigation for cholesteatoma surgery for identification and documentation of ossicular status, location and extent of disease, erosion of tegmen or sinus or labyrinthine dehiscence, with the exception of facial canal dehiscence. Although it serves as road map for surgery, it still has some false positives and false negatives and the importance of a skilful, aware and alert surgeon cannot be overemphasized.

The Correlation Between Preoperative Findings of High-Resolution Computed Tomography (HRCT) and Intraoperative Findings of Chronic Otitis Media (COM)

Objectives:

The aim of this study was to investigate the correlation between the preoperative findings of high-resolution computed tomography (HRCT) of temporal bone in chronic otitis media (COM) and the intraoperative findings.

Methods:

This retrospective study was conducted in the ORL-HNS Unit at Ohud Hospital, Medina, Saudi Arabia, during the period from January to September 2018. We included all patients with COM, and an informed consent was obtained from all participants. The HRCT images were studied in comparison with the intraoperative findings. The parameters of comparison were tympanic membrane, middle ear structures, and the status of cholesteatoma.

Results:

A total of 39 patients were included in the analysis: 14 male and 25 female patients. The age range was 9 to 50 years. As a result of the comparison between HRCT findings and intraoperative observations, we found that incus erosion through computed tomography (CT) was the same as during surgical observation in 12 cases (30.8%). Malleus appeared eroded on CT in 1 case (2.6%); however, 5 cases were seen with that observation during operation (12.8%). Cholesteatoma was similarly seen in the CT scan and during surgery with a significant relation between intraoperative cholesteatoma extending and HRCT findings of the disease (95% confidence level, P-value = 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value were 100% for detecting sigmoid plate erosion, dura exposure, incus erosion, stapes erosion, and malleus-incus joint discontinuity through preoperative CT.

Conclusions:

Intraoperative findings and HRCT have shown better results with good correlation of diagnostic value regarding the comparisons between recorded observations, especially in detecting sigmoidal plate erosion, dural exposure, incus and stapes erosion, and malleus-incus joint discontinuity. Preoperative CT scan is beneficial and contributory in the decision of indicating surgery to patients.

Is Routine Use of High Resolution Computerized Tomography of Temporal Bone in Patients of Atticoantral Chronic Suppurative Otitis Media without Intracranial Complications Justified?

Role of high resolution computerized tomography (HRCT) of temporal bone is established in cases of atticoantral chronic suppurative otitis media (CSOM) with intracranial complications. Routine use of HRCT in management of patients of atticoantral CSOM without intracranial complications has been an issue of debate. The aim of this study was to evaluate the routine use of HRCT of temporal bone in such cases. This study was a prospective study done at LG hospital, AMC MET Medical College, Ahmedabad to evaluate and compare the temporal bone findings in HRCT and intraoperative findings in 100 patients with atticoantral CSOM. All patients underwent HRCT screening followed by surgical exploration of middle ear cleft. In extent of disease HRCT showed very high sensitivity and specificity for epitympanum (100, 94%) and mesotympanum (98, 98%) areas. It gave valuable information of disease extent in hidden areas like sinus tympani and facial recess of mesotympanum. HRCT satisfactorily delineated malleus and incus erosion but had 75% sensitivity for detecting erosion of stapes suprastructure, though specificity was of 97%. For bony anatomical landmarks HRCT showed very high sensitivity and specificity for detecting erosion of lateral semicircular canal, tegmen tympani and sinus plate. Detection of facial canal erosion on HRCT had moderate sensitivity of 75%. We concluded that routine use of HRCT is justified as a reliable preoperative tool in patients with atticoantral CSOM without intracranial complications and it helps to plan type of surgical intervention. HRCT has limited role to distinguish between granulations and cholesteatoma and also to delineate stapes supra structure and facial nerve canal.

Radiologic and surgical findings in chronic suppurative otitis media

Our aim in this study was to evaluate the efficiency of preoperative temporal bone computed tomography (CT) in detecting pathologic conditions in patients with chronic suppurative otitis media (CSOM). The intraoperative findings and temporal bone CT results of 350 patients who were diagnosed with CSOM between September 1, 2010, and June 1, 2013, were compared. Comparison parameters were as follows: the presence of cholesteatoma, erosion of the outer ear bone canal, erosion of the middle ear chain, erosion of the dural plate, erosion of the lateral semicircular canal, erosion of the sigmoid sinus wall, and dehiscence of the facial canal. The contribution of CT was limited in showing the outer ear canal destruction, dural plate destruction, facial canal destruction, lateral semicircular canal destruction, and destruction of the sigmoid sinus wall. However, CT was more sensitive in detecting cholesteatoma and erosion of the ossicular chain. These results indicate that preoperative CT of patients with CSOM serves as an important guide for otolaryngologists, although there are limitations in the evaluation of the CT results.

Role of High Resolution Computed Tomography in Evaluation of Pathologies of Temporal Bone

BACKGROUND

High Resolution Computed Tomography (HRCT), a modification of routine CT, provides a direct visual window in the temporal bone providing minute structural details. Purpose of the present study was to evaluate the normal variations, pathological processes (infections and congenital anomalies) and their extent involving the temporal bone along with their complications on HRCT and to correlate these imaging findings surgically, wherever available.

MATERIALS AND METHODS

The prospective study included 50 patients who were referred to the radiology department with clinically suspected temporal bone or ear pathologies. After detailed clinical examination, the patients were subjected to high resolution computed tomography (HRCT) examination. The imaging findings were correlated with the surgical findings wherever available. The surgical findings were considered as final.

RESULTS

From a total of 50 cases, 83.33% had cholesteatoma. The surgical and radiological findings showed a high level of sensitivity (89.29%) in the identification of cholesteatoma. HRCT provides a good sensitivity of 80.65% in the identification of changes to the ossicular chain despite the presence of surrounding soft tissue. HRCT was highly informative in identification of erosion of lateral semicircular canal. In diagnosis of facial canal dehiscence HRCT had a low sensitivity of 33.33%. In the evaluation of any congenital abnormality of the ear HRCT proved to be beneficial in depicting the anatomical details.

CONCLUSION

The clinical and radiological findings showed a high level sensitivity with intraoperative findings as regards to the presence of cholesteatoma, changes of the ossicular chain and erosion of the lateral semicircular canal. HRCT findings, in the treatment of any congenital abnormality of the ear were a good guide to the surgeon for planning and management.

Computed tomography in chronic suppurative otitis media: value in surgical planning

The present study was conducted prospectively to evaluate how accurately high resolution computed tomography scanning could define the extent and severity of the underlying disease in patients with chronic suppurative ear disease, thus, helping convert a surgical exploration into a planned procedure. Sixty adult consecutive cases of chronic suppurative otitis media underwent a detailed high resolution computed tomography by a single radiologist. The recorded radiological findings in various heads were then compared to the surgical findings during mastoid exploration of these patients by a single otologist and the two statistically compared. The presence and distribution of soft tissue in the middle ear cleft and mastoid could confidently be predicted using this modality. The malleus, body and short process of incus were well visualized, but not the long process of incus and the stapes suprastructure. Lateral semicircular canal fistulae could be demonstrated with an acceptable degree of accuracy. It was possible to detect facial nerve dehiscence and defects in tegmen tympani in significant number of cases although, statistical values were low for these structures. High resolution scanning is a modality which can accurately image the pathological anatomy in unsafe chronic suppurative otitis media. Otologists should use it more often, especially in complicated cases as an adjunct to better preoperative assessment, and thus, the surgical outcome. Its accuracy is likely to improve with larger studies and better experience, wherein its routine use may become justifiable.

An evaluation of preoperative computed tomography on patients with chronic otitis media

This study aimed to compare the veracity of computed tomography findings on patients undergoing surgery for chronic otitis media (COM) with the surgical findings, and to determine to what extent the preoperative computerized tomography (CT) findings are useful to the surgeon. A series of 56 patients with COM undergoing preoperative CT scanning followed by surgical exploration of the middle ear and mastoid. Operative notes were recorded and data collected on the nature of soft tissue masses, the status of the ossicles, presence or absence of facial canal dehiscence and semicircular canal (SCC) dehiscence and the presence or absence of dural plate erosion, and sigmoid sinus thrombosis. Fifty-six patients were recruited in the study, 30 males and 26 females. The age range was from 16 to 67 years with a mean of 26.51 ± 1.4 years. The preoperative CT scan imaging in cases of cholesteatoma, ossicular chain erosion and SCC dehiscence have good correlation with the intraoperative findings. The specificity of preoperative CT scan in detecting facial canal dehiscence, dural plate erosion and sigmoid sinus thrombosis in patient of COM were weak. Preoperative computed tomography evaluation is fairly useful especially in cases of cholesteatoma. According to the results of this study, CT is of value particularly in the definition of cholesteatoma, and in determining ossicular chain erosion and semicircular canal fistula.

Diffusion-weighted MR imaging for evaluation of pediatric recurrent cholesteatomas

OBJECTIVE

To compare the efficiency of diffusion-weighted MR imaging (MRI) vs. high resolution CT in predicting recurrent or residual cholesteatoma in children who underwent prior middle ear surgery.

DESIGN

Prospective study.

SETTING

Tertiary care university hospital.

PATIENTS

Seventeen patients (4 with 2 recurrences) aged 5-17 years (mean 11.4) previously surgically treated for a cholesteatoma of the middle ear, were included for follow-up with systematic CT scan and MRI, between 2005 and 2007.

METHODOLOGY

CT scan was performed on a Siemens Somaton 64 (0.5/0.2 mm slices reformatted in 0.5/0.3 mm images), parallel and perpendicular to the lateral semi-circular canal for each ear (100 mmx100 mm FOV). MRI was undertaken on a Siemens Avanto 1.5 T unit, with an adapted protocol for young children. Diagnosis of recurrent cholesteatoma was based on the evidence of a hyperintense image at B1000 on diffusion-weighted images. Results of CT scan and MRI were compared with operative diagnosis.

RESULTS

Nine patients had a positive MRI, among which 8 had cholesteatoma confirmed during revision surgery. In the 12 negative MRI cases, 5 were positive on revision surgery. None of these lesions was over 3mm. Two of them were diagnosed on the CT scan. CT scan alone had a positive predictive value of 75%, and a negative predictive value of 58%.

CONCLUSION

Diffusion-weighted MRI is associated with a high positive predictive value for the detection of recurrent cholesteatoma. CT scan remains the first choice imaging technique. In case of doubtful CT scan, diffusion-weighted MRI could confirm a recurrence or, when negative, avoid second-look surgery.

Radiologic evaluation of the ear anatomy in pediatric cholesteatoma

The aim of the study was to describe computed tomography (CT) findings in middle ear cholesteatoma in pediatric patients. A cohort of 32 children with cholesteatoma (3-14 years old) entered the study. From them, 30 presented acquired cholesteatoma (AC), and 2 presented congenital cholesteatoma. All of the children were investigated using CT before surgery of the middle ear and mastoid. Computed tomography was performed with 1- or 2-mm axial and coronal sections of both temporal bones. Nineteen children with AC (63.3%) revealed a diffuse soft-tissue density isodense with muscle, whereas in 6 of them, the mass mimicked inflammation. The remaining revealed localized soft-tissue mass with partially lobulated contour. In AC, ossicular erosion was detected in 23 cases (76.7%), abnormal pneumatization in 19 cases (63.3%), and erosion-blunting of spur and enlargement of middle ear or mastoid in 8 cases (26.7%). The 2 congenital cholesteatomas revealed soft-tissue mass with polypoid densities, while a semicircular canal fistula was detected in one of them. High-resolution CT facilitates early diagnosis and appropriate treatment of pediatric cholesteatoma by assessing the anatomic abnormalities and the extent of disease, which are crucial in middle ear and mastoid surgery.

The role of preoperative CT scan in patients with chronic otitis media

Chronic otitis media may be due to chronic mucosal disease or cholesteatoma. Differentiating the two is usually achieved by clinical examination. The computed tomography (CT) scan is the standard imaging technique for the temporal bone, but its exact role in the preoperative assessment of patients with chronic otitis media is controversial. In this retrospective study we compared preoperative CT results with operative findings in 50 patients who had scan between January 2003 and December 2007. We analyzed the clinical presentation and checked if CT scan confirmed or excluded the presence of cholesteatoma and if this was affected by previous surgery. We concluded that CT scan could not be relied on to differentiate cholesteatoma from chronic mucosal disease. It should be used selectively in the preoperative preparation only if complications of the disease suspected.

Middle ear cholesteatoma: characteristic CT findings in 64 patients

BACKGROUND

High resolution computerized tomography (HRCT) is valuable for detection of early erosive changes suggestive of cholesteatoma. The aim of our study was to determine characteristic CT findings in patients with middle ear cholesteatoma.

METHODS

We conducted a retrospective review of CT scans and surgical and histopathological reports in 64 patients with middle ear cholesteatoma (35 male, 29 female; age range, 7-80 years, median age, 22 years). CT scans were evaluated for the presence of intra-tympanic non-dependent soft tissue density, the extent of middle ear involvement, bone expansion and thinning, and bone erosions involving the ossicles and adjacent structures.

RESULTS

Middle ear cholesteatoma was more common in male patients and in patients aged 20-35 years. All patients had soft tissue density in the middle ear. Fifty-nine (92%) had expansion of the aditus and mastoid antrum, 59 (92%) had erosions of the ossicles, with involvement of the long process of the incus in 48 (75%), 55 (86%) had an eroded scutum, 55 (86%) an eroded facial nerve canal, 57 (89%) an eroded Koerner's septum, which was totally destroyed in 19 (27%), 48 (75%) had tegmen erosion, and 63 (98%) had erosions of the antral walls. The correlation of pre-operative CT with surgical and histopathological findings was 97%.

CONCLUSION

Middle ear cholesteatoma is a distinct clinical entity with characteristic findings that may be suggested by CT imaging. These findings should alert the clinician to the possibility of cholesteatoma, which will guide in the surgical approach and treatment plan.

CT scanning of middle ear cholesteatoma: what does the surgeon want to know?

The history of surgery for middle ear cholesteatoma is of an evolution of techniques to meet the challenges of inaccessible disease and of post-operative cavity management. The concept has traditionally been of exploration guided by awareness and anticipation of all, possibly asymptomatic, complications. Modern imaging reliably demonstrates surgical anatomy, dictating the ideal approach, forewarns of complications and may reveal the extent of disease. An apparent resistance amongst otologists to universal CT scanning prior to mastoidectomy contrasts with the enthusiasm of skull base surgeons or rhinologists for appropriate imaging.

Computed tomography and magnetic resonance imaging of pathologic conditions of the middle ear

Computed tomography (CT) is an excellent technique for demonstrating even small abnormalities of the thin and complex bony structures of the middle ear. For this reason, it is the modality of choice in the study of conductive hearing loss (CHL). However, not every patient complaining of CHL requires a CT study. In fact, established indications encompass complex conditions, such as the complications of acute and chronic otomastoiditis, the postoperative ear in chronic otomastoiditis or in the localization of prosthetic devices, and the assessment of congenital or vascular anomalies. Particularly, the precise extent of bone erosion associated with cholesteatoma is correctly demonstrated by high resolution CT. Conversely, although fistulization through the tegmen tympani or the posterior wall of temporal bone is usually detectable by CT, the actual involvement of meninges and veins are better assessed by magnetic resonance (MR). MR is also indicated when complicated inflammatory lesions are suspected to extend into the inner ear or towards the sigmoid sinus or jugular vein. Neoplasms arising from or extending into the middle ear require the use of both techniques as their combined data provide essential information. Most important data for surgical planning concern the destruction of thin bony structures and the relationships of the lesion with the dura and surrounding vessels. DSA and interventional vascular techniques maintain an essential role in the presurgical work-up and embolization of paragangliomas extended into the middle ear.

Segmental anatomy of the temporal bone

More of us suffer from hearing loss than from visual impairment, coronary artery disease, and cancer combined. Auditory dysfunction is detected in less than one third of newborns afflicted and is underdiagnosed in the elderly. Despite biomedical and technological advances, our understanding of vestibular dysfunction has grown little. Forming part of the lateral and inferior surfaces of the skull, the temporal bone contains the organs of hearing and balance. Diagnosis of diseases in these important regions requires adequate clinical information and a thorough knowledge of normal temporal bone anatomy to recognize abnormal findings when present. This article dissects the temporal bone into segments, describes the relevant radiologic anatomy of each, and discusses the imaging appropriate to specific concerns.