A systematic review of diffusion-weighted magnetic resonance imaging in the assessment of postoperative cholesteatoma

Early non-EPI DW-MRI after cholesteatoma surgery

OBJECTIVE

Middle ear cholesteatoma may lead to the erosion of the bony structures of the temporal bone, possibly causing intra- and extracranial complications. Surgical treatment is mandatory, and due to possible residual/recurrent disease, the use of reliable diagnostic methods is essential. Our study aimed to evaluate the reliability of non-EPI DW-MRI for the follow-up of cholesteatoma after surgery.

METHODS

In a study group including 53 consecutive patients who underwent surgery for cholesteatoma at a tertiary university hospital, an imaging protocol was applied, including non-echo planar diffusion-weighted imaging magnetic resonance (MR) at 1 month after surgery and then at 6 and 12 months after surgery. Based on the combination of preoperative assessment and intraoperative findings, the study group was divided into 3 subgroups: petrous bone (PB) cholesteatoma, complicated cholesteatoma and uncomplicated cholesteatoma. PB cholesteatoma patients were treated by a subtotal petrosectomy, whereas complicated and uncomplicated cholesteatoma patients were treated either by a canal wall up procedure or a retrograde (inside-out) canal wall down technique with bone obliteration technique (BOT).

RESULTS

The results show that patients who had positive findings on non-EPI DW-MRI scans 1 month after surgery consequently underwent revision surgery during which residual cholesteatoma was noted. All the patients who displayed negative findings on non-EPI DWI-MRI scan at 1 month after surgery did not show the presence of a lesion at the 6- and 12-month evaluations. The 6 patients who displayed residual cholesteatoma at the 1-month follow-up presented dehiscence/exposure of the facial nerve canal at the primary surgery, mostly at the level of the labyrinthine segment.

CONCLUSION

Non-EPI DW-MRI is a useful and reliable tool for follow-up cholesteatoma surgery, and when applied early, as was done in the protocol proposed in the present study, this tool may be used to detect the presence of residual cholesteatoma in some patients, prompting the planning of early revision surgery.

Toward Improved Detection of Cholesteatoma Recidivism: Exploring the Role of Non-EPI-DWI MRI

Background: Cholesteatoma is a lesion capable of destroying surrounding tissues, which may result in significant complications. Surgical resection is the only effective treatment; however, the presence of cholesteatoma recidivism is common. This study evaluated the effectiveness of the Attic Exposure-Antrum Exclusion (AE-AE) surgical technique in treating cholesteatomas and identifying factors associated with recidivism. Additionally, the study aimed to assess the utility of non-echo-planar diffusion MRI (non-EPI-DWI MRI) in detecting cholesteatoma recidivism in patients undergoing AE-AE surgery. Methods: The study involved 63 patients who underwent AE-AE surgery for primary acquired cholesteatoma and were followed up clinically and radiologically for at least five years. The radiological follow-up included a non-EPI-DWI MRI. Results: Results showed that the AE-AE technique successfully treated cholesteatomas, with a recidivism rate of 5.2%. The study also found that non-EPI-DWI MRI was a useful diagnostic tool for detecting cholesteatoma recidivism, although false positives could occur due to the technique's high sensitivity. As Preoperative Pure-tone average (PTA) increases, there is a higher probability of cholesteatoma recidivism in imaging tests (p = 0.003). Conclusions: Overall, the study highlights the importance of the AE-AE surgical technique and non-EPI-DWI MRI in managing cholesteatoma recidivism in patients, providing valuable insights into associated risk factors and how to manage recidivism. Non-EPI-DWI MRI can assist in patient selection for revision surgery, reducing unnecessary interventions and associated risks while improving treatment outcomes and patient care.

Evaluation of magnetic resonance imaging to detect cholesteatoma in clinical healthcare

BACKGROUND

Non-Echo-Planar Diffusion Weighed Magnetic Resonance Imaging (non-EPI DW MRI) plays a role in the planning of cholesteatoma surgery.

OBJECTIVES

To outline the usage of Non-EPI DW MRI in cholesteatoma diagnostics and to determine its accuracy, using otosurgery diagnostics as reference standard.

MATERIAL AND METHODS

A retrospective descriptive study. All subjects operated, with suspicion of cholesteatoma as indication, that had a preceding examination with non-EPI DW MRI, between October 2010 and March 2019. Calculating sensitivity, specificity, predicative values, and likelihood ratios, using non-EPI DW MRI as index test and diagnosis from otosurgery as reference standard.

RESULTS

Fifty-two subject episodes were included. Non-EPI DW MRI had a sensitivity of 0.50, specificity of 0.75, positive and negative predictive values of 0.74 and 0.52 and, positive and negative likelihood ratios of 2.0 and 0.67 respectively.

CONCLUSIONS AND SIGNIFICANCE

There is a clear annual trend with increased numbers of executed examinations during the study period. The diagnostic accuracy of non-EPI DW MRI does not reach acceptable levels in the existing everyday routine practice conditions. The accuracy of the examination increases when interpreted by an experienced radiologist and when using the definition of cholesteatoma recommended by EAONO/JOS.

Cost-Effectiveness of Diffusion-Weighted Magnetic Resonance Imaging Versus Second-Look Surgery in Treating Cholesteatoma: A Modeling Study

OBJECTIVE

To evaluate whether canal wall-up (CWU) tympanomastoidectomy with diffusion-weighted magnetic resonance imaging (DW-MRI) is a cost-effective method of treating cholesteatoma compared with CWU with second-look surgery.

DESIGN AND SETTING

Cost-effectiveness analysis was conducted using a Markov state transition model. The simulation model adhered to the Panel Recommendations on Cost-Effectiveness in Health and Medicine established by the US Public Health Service. One-way and Monte Carlo probability sensitivity analyses were conducted for validation.

INTERVENTIONS

Tympanomastoidectomy with DW-MRI versus tympanomastoidectomy with second-look surgery.

MAIN OUTCOME MEASURES

Effectiveness and health utility were measured using quality-adjusted life years (QALYs). Costs were derived from Medicare reimbursement using the perspective of the payer. Probabilities for outcomes and complications were taken from existing literature. Cost-effectiveness was assessed using the incremental cost-effectiveness ratio.

RESULTS

With base case analysis, the total cost was $15,069 when treated with CWU and second-look surgery versus $13,126 when treated with CWU and DW-MRI. The second-look treatment pathway yielded 17.05 QALYs, whereas the DW-MRI pathway yielded 16.91 QALYs in terms of health benefit accrued across the lifetime of the patient. The cost-effectiveness incremental cost-effectiveness ratio was $21,800/QALY. Using the conventional $50,000 willingness-to-pay threshold, second-look surgery was the more cost-effective approach 63.7% of the time by simulation.

CONCLUSIONS

Both treatment pathways were found to be cost-effective, with second-look surgery incrementally cost-effective 63.7% of the time. Assumptions were validated by one-way and Monte Carlo probability sensitivity analysis.

PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED

There is ample variation in treatment pathways regarding usage of DW-MRI and second-look surgery for cholesteatoma.

LEARNING OBJECTIVE

To evaluate the cost-effectiveness of DW-MRI and second-look surgery approaches, accounting for health-related quality-of-life outcomes and costs for the duration of the patient lifetimes.

DESIRED RESULT

To inform the discussion on the treatment for cholesteatoma given emergent noninvasive technologies.Level of Evidence: Level III.Indicate IRB or IACUC: Exempt.

Early Magnetic Resonance Imaging to Diagnose Residual Cholesteatoma in Children and Benefit of Radiological Rereview

OBJECTIVE

Non-echo-planar diffusion-weighted (DW) magnetic resonance imaging (non-EPI MRI) is the appropriate sequence to detect residual cholesteatoma. In the child, MRI may be clinically useful to determine the timing of the second-look procedure. The aim of this paper was to retrospectively evaluate the performance of early MRI (before the 18th postoperative month) in detecting residual cholesteatoma in children after review by experienced specialized neuroradiologists.

STUDY DESIGN

Retrospective study.

SETTING

One university center comparative cohort.

METHODS

All patients who had a 2-staged procedure for cholesteatoma with an MRI before the second stage from 2010 to 2020 were included and analyzed. Three pediatric neuroradiologists reviewed all the images blinded to the surgical result.

RESULTS

N = 141 cholesteatoma events (140 children) were included with a mean age at MRI of 10 (±4) years old. Non-EPI MRIs were performed 10.7 (±3.8) months after the first-stage surgery and 2.2 (±2.6) months before the second-stage procedure. Non-EPI MRI had a 0.57 sensitivity (SE) and 0.83 specificity (SP). MRI was reviewed in 112 cases. The diagnosis was corrected in 17 cases (15.1%) (3 true positives, 7 false negatives, and 7 false positives). SE = 0.63 (p = 0.1) and SP = 0.92 (p = 0.08) after rereading.

CONCLUSION

Early MRI's SE is poor but SP is excellent after rereading. Evidence does not support the use of early non-EPI MRI to modify the surgical strategy or to postpone the second look. If performed, early non-EPI MRI should be read by specialized experienced radiologists with all 3 sequences (T1, T2, and non-EPI DW) and apparent diffusion coefficient calculation, especially in cases of otitis media with effusion.

Cartilage grafts mimicking cholesteatoma recurrence on diffusion-weighted magnetic resonance imaging: a case series

BACKGROUND

Cholesteatomas present a high risk for residual and recurrent disease, and the surveillance of post-operative patients can be challenging. Diffusion-weighted magnetic resonance imaging is becoming the preferred method for investigating recidivism; however, false positive imaging findings increase the risk of patients undergoing unnecessary second look surgery.

CASE REPORTS

This study reports two patients with false positive diffusion restriction associated with cartilage grafts that mimicked cholesteatoma and resulted in second look surgery with no disease found at operation. This study also discusses the related medical literature, including potential causes of abnormal diffusion restriction and methods to negate this.

CONCLUSION

Caution should be exercised when considering second look surgery in the presence of a cartilage graft and a high confidence of disease clearance. A multi-disciplinary approach is recommended for the operating surgeon to review the images with a radiologist.

Quality of Life After Modified Rambo Ear Canal Closure in Pediatric and Adult Patients

OBJECTIVE

To present the surgical and quality of life (QOL) outcomes of patients who underwent blind sac closure of the external auditory canal (EAC) via a modified Rambo approach.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary academic referral center.

METHODS

All patients who underwent EAC closure with a modified Rambo approach between 2015 and 2021 were evaluated. Complication rates, QOL estimations from a validated survey, and subjective cosmetic reports were analyzed.

RESULTS

Thirty-five ears were closed in 31 patients. The most common indication for surgery was related to cochlear implantation and cochlear malformation or cholesteatoma (31.4%). No case involved an immediate complication requiring revision surgery, and 4 ears (11.4%) were suspected of having cholesteatoma within the surgical cavity at a mean 28.6-month follow-up. Adults (≥18 years) had significantly higher QOL scores than children in the medical resource subscale of the Chronic Ear Survey (P < .01), and patients undergoing concurrent EAC closure and skull base tumor removal scored higher than others (P = .04). Females reported higher cosmetic scores than males (P = .04). QOL and cosmetic scores compared favorably to previously published data involving the management of otologic disease.

CONCLUSIONS

Ear canal closure can be a useful technique for select adult and pediatric patients. Patient and surgeon concerns regarding QOL and cosmesis in ear canal closure should be explored prior to employing this surgical technique, though the present data suggest that the modified Rambo approach to closure is generally associated with reasonable outcomes in both areas.

Updates in paediatric cholesteatoma

PURPOSE OF REVIEW

The management of paediatric patients with cholesteatoma is complex, as the disease process is more aggressive in children than adults. New technologies and practice adaptations currently help optimize the surgical management and monitoring of these challenging patients.

RECENT FINDINGS

Several options of surgical management are available and are associated with equal if not improved outcomes. Technologic advancements in endoscopic ear surgery, the discovery of chemical-assisted dissection of cholesteatoma and advanced imaging protocols have enabled surgeons to better care for patients with this complex disease process.

SUMMARY

The advances in endoscopic ear surgery, the discovery of Mesna as a chemically assisted dissection agent to improve recidivism rates and the use of specific diffusion-weighted MRI protocols enable the otologic surgeon to better care for these paediatric patients.

The Clinical Role of Diffusion-Weighted MRI for Detecting Residual Cholesteatoma in Canal Wall up Mastoidectomy

OBJECTIVES

The purpose of this study was to assess the value of the diffusion MRI with the non-echoplanar imaging (Non-EPI) technique for follow-up the post-operative patients to detect residual cholesteatomas.

STUDY DESIGN

This prospective study was performed on 40 patients. All patients were at least one year after Canal Wall Up mastoidectomy surgery for cholesteatoma and scheduled for a second-look surgery.

PATIENTS AND METHODS

This prospective study was performed on 40 patients. All patients were subjected to Canal Wall Up surgery and planned for the second-look operation. After one year as removal of choleasteatoma is uncertain in first surgery. The study done at Tertiary referral centers (Ain shams, Mansoura, and Minia university hospitals), non-echoplanar diffusion MRI (NEP-DWI) technique for follow-up the post-operative patients to detect residual cholesteatomas, then second look surgery done 2 weeks after MRI.

RESULTS

Forty patients underwent MRI with Non-echoplanar diffusion-weighted imaging (NEP-DWI). Twenty-six patients had positive MRI results with the remaining 14 patients had negative results. These results were compared to operative findings. All positive MRI cases showed positive intra-operative findings. Ten of negative MRI cases showed negative intra-operative findings. Four of DWI-negative cases showed small cholesteatomas.

CONCLUSION

The use of NEP-DWI is a valuable tool in detecting residual cholesteatoma that could replace the second look surgery in many cases.

Utility of Non-EPI DWI MRI Imaging in Cholesteatoma: The Indian Perspective

The purpose of this prospective observational study was to evaluate the diagnostic performance of non-EPI-based techniques, in detecting both primary and residual/recurrent cholesteatoma in a tertiary care center. 56 patients (25 female and 31 male) aged between 6 and 59 years were prospectively evaluated for the presence or absence of cholesteatoma. This included both primary and postoperative recurrent cholesteatoma (16). All the patients underwent sequential CT scans of temporal bones and non-EPI DWI (Non-Echo Planar Diffusion-Weighted Imaging) MRI techniques. The findings were correlated with surgical findings regarding the presence or absence of cholesteatoma. The size of cholesteatoma that was diagnosed on non-EPI DWI MRI was measured. The smallest size was 6 mm and the largest one was 21 mm. The accuracy of non-EPI DWI MRI in diagnosing cholesteatoma (primary and recurrent) was 97.5%. Whereas in diagnosing recurrent cholesteatoma accuracy was 100%. Accuracy of non-EPI DWI MRI is very high in diagnosing cholesteatoma especially in recurrent cholesteatoma and can potentially replace second look surgery when intact canal wall techniques are used. The technique is best used with a CT Scan of the temporal bone to depict bony changes, anatomical variants, or complications. The combination of HRCT and non-EPI DWI needs to be employed in diagnosing primary and recurrent cholesteatoma to maximize the diagnostic benefit as they are complimentary.

Diagnosis and Treatment Modalities of Cholesteatomas: A Review

A cholesteatoma is an abnormal, noncancerous skin growth that can appear beneath the eardrum in the center of your ear. Although it might be a congenital condition, frequent middle ear infections are the main culprit. A cholesteatoma frequently appears as a cyst or sac that exfoliates the skin's outer layers. As these dead skin cells build up, the growth can enlarge and penetrate intratemporal tissues, leading to various intracranial and extracranial difficulties that can compromise facial muscles, hearing, and balance. Cholesteatomas were recognized more than three centuries ago. A cholesteatoma can develop into a serious condition if it is not treated right away. Because of its fast development and invasive nature, it can cause several consequences, some of which can be fatal for people without access to advanced medical treatment. There are no effective nonsurgical treatments available right now. It will be necessary to have a thorough awareness of both previous developments and more current ones to develop an appropriate management approach for this condition. The background information on acquired middle ear cholesteatomas is briefly reviewed in this paper. We also take into account categorization-, epidemiology-, histology-, and pathogenesis-related difficulties, and we carefully review current management and diagnosis approaches.

The Efficacy of DW and T1-W MRI Combined with CT in the Preoperative Evaluation of Cholesteatoma

Objective: This study aims to assess the efficacy of diffusion-weighted (DW) and T1-weighted (T1W) magnetic resonance imaging (MRI) combined with high-resolution computed tomography (HRCT) (together as DW-T1W-CT) in the preoperative evaluation of the presence and extent of cholesteatoma, which helps determine whether a patient is suitable for transcanal endoscopic ear surgery (TEES). Methods: This retrospective study included 35 patients (18 male and 17 female) aged from 2 to 81 years diagnosed with chronic otitis media with or without cholesteatoma, who had received surgical treatment and a preoperative MRI and HRCT during the period of December 2015 to December 2020 at Cathay General Hospital. We compared the preoperative DW-T1W-CT findings with the intraoperative findings and final pathologic diagnosis. The accurate predictive value was evaluated using the presence of cholesteatoma and its extent. Results: Regarding the efficacy of detecting cholesteatoma, we found a sensitivity of 92% (23/25 cases with cholesteatoma), a specificity of 90% (9/10 cases without cholesteatoma), and an overall accurate predictive value of 91.4% (32/35) by using combined DW-T1W-CT imaging. With regard to evaluating the extent of cholesteatoma, the combined DW-T1W-CT images obtained an accurate predictive value of 84% (21/25 cases of cholesteatoma). Conclusion: Combined DW-T1W-CT has been proven to be a reliable tool in detecting the presence of cholesteatoma. It is also useful in preoperatively depicting the extent of cholesteatoma, which is crucial for determining whether a patient is suitable for TEES, aiding in surgical planning and patient consultation.

Cost-effectiveness of Canal Wall-Up vs Canal Wall-Down Mastoidectomy: A Modeling Study

OBJECTIVE

To assess the relative lifetime costs, benefits, and cost-effectiveness between the 2 approaches, canal wall-up (CWU) and canal wall-down (CWD) tympanomastoidectomy, used in the treatment of cholesteatomas.

STUDY DESIGN

Markov state transition model.

SETTING

Tertiary academic health system.

METHODS

A Markov state transition model was used to simulate outcomes across the patient lifetime. Outcome and complication probabilities were obtained from the existing literature. Costs were calculated from the payer perspective, with procedure, hospital, clinic, and physician cost derived from Medicare reimbursement. Quality-adjusted life years (QALYs) were used to represent effectiveness and utility. One-way and probability sensitivity analyses (PSAs) were conducted.

RESULTS

The base case analysis, assuming a 40-year-old patient, yielded a lifetime cost of $14,214 for a patient treated with the CWU approach assuming second-look surgery and $22,290 with a CWD approach. CWU and CWD generated a benefit of 17.11 and 17.30 QALYs, respectively. The incremental cost-effectiveness ratio for CWU was $43,237 per QALY. The Monte Carlo PSA validated the base case scenario. Using a standard $50,000 willingness-to-pay threshold, CWD was the more cost-effective approach and was selected 54.8% of the time by the simulation.

CONCLUSION

Both CWU and CWD were found to be cost-effective, with CWD being cost-effective 54.8% of the time at a WTP threshold of $50,000. The assumptions used in the analysis were validated by the results of 1-way and PSA.

[Combination of CT and MRT in the diagnostic of middle ear cholesteatoma. Fusion technology is precise localization tool]

Computed tomography (CT) and magnetic resonance imaging (MRI) methods of the middle ear cholesteatoma diagnostic have its advantages and disadvantages. Fusion technology is a post-processing process of CT and MRI images. Its main advantage is the localization of MR-hyperintensive cholesteatoma within the bony anatomical structures obtained on CT, which provides the surgeon with important information both before planning the primary surgical intervention and during a second revision for recurrent cholesteatoma.

New Compartmental Reading Method for MRI Enables Accurate Localization of Cholesteatomas With High Sensitivity and Specificity

OBJECTIVES

Cholesteatoma is an inflammatory disease, frequently observed in childrens and young adults, with a risk of relapse or recurrence. The few studies which analyzed cholesteatoma localization on magnetic resonance imaging (MRI) usually merged CT-MR images or relied on their authors' anatomical knowledge. We propose a compartmental reading method of the compartments of the middle ear cavity for an accurate localization of cholesteatomas on MR images alone.

MATERIAL AND METHODS

Our method uses easily recognizable anatomical landmarks, seen on both computed tomography (CT) and MRI, to delimit the middle ear compartments (epitympanum, mesotympanum, hypotympanum, retrotympanum, protympanum, antrum-mastoid cavity). We first tested it on 50 patients on non-enhanced temporal bone CT. Then, we evaluated its performances for the localization of cholesteatomas on MRI, compared with surgery on 31 patients (validation cohort).

RESULTS

The selected anatomical landmarks that delimited the middle ear compartments were applicable in 98 to 100% of the cases. In the validation cohort, we were able to accurately localize the cholesteatoma on MRI in 83% of the cases (n = 26) with high sensitivity (95.7%) and specificity (98.6%).

CONCLUSION

With our compartmental reading method, based on the recognition of well-known anatomical landmarks to differentiate the compartments of the middle ear cavity on MRI, we were able to accurately localize the cholesteatoma with high (>90%) sensitivity and specificity. Such landmarks are widely applicable and only require limited learning time based on key images. Accurate localization of the cholesteatoma is useful for the choice of surgical approach.

Application of a novel transcanal keyhole technique in endoscopic cholesteatoma surgery

BACKGROUND

It is difficult to deal with epitympanic cholesteatoma in otologic surgery. The keyhole technique can realize minimally invasive surgery and reconstruct the middle ear canal.

OBJECTIVE

To explore the clinical application of keyhole technique in primary and second-look surgery in middle ear cholesteatoma.

MATERIALS AND METHODS

34 cases were analyzed retrospectively in terms of residual and recurrence rate, safety (adverse events) and hearing performance at long-term follow-up. The application of the technique in primary or second stage operation was evaluated and the operation was performed by transanal endoscopy or combined approach.

RESULTS

The cholesteatoma revealed by CT before operation was limited to the attic in 23 patients, of which 16 had the same imaging range as that of the keyhole technique. The preoperative imaging findings of 11 showed that the attic cholesteatoma may have extended into the mastoid, of which only 6 cases were confirmed by keyhole technique. An endoscopic second-look surgery using the keyhole technique was performed for these patients, 2 were confirmed to have residual lesions in the attic.

CONCLUSIONS

The keyhole technique under otoendoscopy can be used flexibly and conveniently in the second-look surgery to make up for the shortage of diffusion-weighted magnetic resonance imaging.

Non-EPI versus Multishot EPI DWI in Cholesteatoma Detection: Correlation with Operative Findings

BACKGROUND AND PURPOSE

Although multishot EPI (readout-segmented EPI) has been touted as a robust DWI sequence for cholesteatoma evaluation, its efficacy in disease detection compared with a non-EPI (eg, HASTE) technique is unknown. This study sought to compare the accuracy of readout-segmented EPI with that of HASTE DWI in cholesteatoma detection.

MATERIALS AND METHODS

A retrospective review was completed of consecutive patients who underwent MR imaging for the evaluation of suspected primary or recurrent/residual cholesteatomas. Included patients had MR imaging examinations that included both HASTE and readout-segmented EPI sequences and confirmed cholesteatomas on a subsequent operation. Two neuroradiologist reviewers assessed all images, with discrepancies resolved by consensus. The ratio of signal intensity between the cerebellum and any observed lesion was noted.

RESULTS

Of 23 included patients, 12 (52.2%) were women (average age, 47.8 [SD, 25.2] years). All patients had surgically confirmed cholesteatomas: Six (26.1%) were primary and 17 (73.9%) were recidivistic. HASTE images correctly identified cholesteatomas in 100.0% of patients. On readout-segmented EPI sequences, 16 (69.6%) were positive, 5 (21.7%) were equivocal, and 2 (8.7%) were falsely negative. Excellent interobserver agreement was noted between reviews on both HASTE (κ = 1.0) and readout-segmented EPI (κ = 0.9) sequences. The average signal intensity ratio was significantly higher on HASTE than in readout-segmented EPI, facilitating enhanced detection (mean difference 0.5; 95% CI, 0.3-0.8; P = .003).

CONCLUSIONS

HASTE outperforms readout-segmented EPI in the detection of primary cholesteatoma and disease recidivism.

Cholesteatoma Localization Using Fused Diffusion-Weighted Images and Thin-Slice T2 Weighted Images

BACKGROUND

Fusion of diffusion-weighted imaging (DWI) to computed tomography (CT) has been touted as a possible technique to improve cholesteatomas localization. This study set out to assess the ability of DWI images fused with thin-slice heavily T2-weighted images to similarly localize surgically-confirmed cholesteatomas.

MATERIALS AND METHODS

A retrospective review was completed of consecutive patients that underwent MR temporal bone imaging (9/2011-3/2020) with both DWI and thin-slice T2-weighted imaging. Included patients underwent surgical resection of primary or recidivistic cholesteatoma after preoperative MR imaging. A neuroradiologist, who was blinded to operative and clinical notes, localized each lesion on both DWI and fused DWI-T2 images in 11 anatomic subdivisions of the temporal bone. Surgical confirmation of cholesteatoma location was used as the gold standard for comparison.

RESULTS

Of 24 included examinations, the average age at time of MR was 48.2 ± 24.7 years; 12/24 (50.0%) were female. Five of 24 had primary cholesteatoma, while the remainder had recidivistic disease. Sensitivity, specificity, and accuracy of unfused DWI images were 52.1%, 88.9%, and 75.8%, respectively. Sensitivity, specificity, and accuracy of fused DWI-T2 images were 57.1%, 94.8%, and 81.8%, respectively.

CONCLUSION

Fused DWI-T2 images outperformed unfused DWI images in the anatomic localization of temporal bone cholesteatomas. This method represents a potential alternative to MR-CT fusion for pre-operative cholesteatoma evaluation, and warrants future investigations. Opposed to MR-CT fusion, this method only necessitates MR sequences and removes the need for additional CT acquisition.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E1662-E1667, 2021.

MRI of the Internal Auditory Canal, Labyrinth, and Middle Ear: How We Do It

MRI is firmly established as an essential modality in the imaging of the temporal bone and lateral skull base. It is used to evaluate normal anatomic structures, evaluate for vestibular schwannomas, assess for inflammatory and/or infectious processes, and detect residual and/or recurrent cholesteatoma. It is also extensively used in pre- and postoperative evaluations, particularly in patients with vestibular schwannomas and candidates for cochlear implantation. Nevertheless, despite the widespread use of MRI for these purposes, many radiologists remain unfamiliar with the complex anatomy and expected imaging findings with such examinations. The purpose of this review is to provide an overview of the most useful MRI sequences for internal auditory canal and labyrinthine imaging, review the relevant anatomy, and discuss the expected appearances of the most commonly encountered pathologic entities. In addition, the features at pre- and postprocedural MRI will be discussed to help ensure that diagnostic radiologists may be of greatest use to the ordering physicians. © RSNA, 2020.

Surgical mapping of middle ear cholesteatoma with fusion of computed tomography and diffusion-weighted magnetic resonance images: Diagnostic performance and interobserver agreement

OBJECTIVE

To assess the diagnostic performance in detecting primary cholesteatoma at various anatomical subsites using Computed Tomography (CT), Diffusion-weighted Magnetic Resonance Imaging (DWMRI) and Fusion of CT and DWMRI (Fusion CT-MRI) images.

STUDY DESIGN

A retrospective study of 22 children identified from a prospective database of surgically treated cholesteatoma cases over a five year period. All cases underwent pre-operative CT, non-echo planar DWMRI and Fusion CT-DWMRI, and with clearly documented surgical findings. For each imaging modality, two radiologists scored for the presence or absence of cholesteatoma with confidence levels at different anatomical subsites. The radiologists were blinded to the surgical findings to which their findings were compared.

SETTING

Large Teaching Hospital in London.

PATIENTS

22 children with cholesteatoma confirmed surgically.

INTERVENTION

CT, DWMRI imaging and fusion CT-MRI.

MAIN OUTCOME MEASURE

Diagnostic performance of subsite localisation of cholesteatoma by CT, DWMRI and fusion CT-MRI imaging with intra-operative findings.

RESULTS

Twenty-two patients were included (12 women and 10 men). The median age of patients was 11 years. When considering all subsites combined, the result for all imaging methods suggested 'good' agreement between both observers. When all subsites were examined together, all methods had relatively high sensitivity values (87% for CT vs 84% for DWMRI vs 85% for fusion CT-DWMRI). Specificity was highest with fusion CT-DWMRI (46% for CT vs 76% for DWMRI vs 97% for fusion CT-DWMRI), as was accuracy (66% for CT vs 80% for DWMRI vs 91% for fusion).

CONCLUSIONS

Our study has demonstrated that fusion CT-DWMRI is superior to DWMRI or CT separately in localizing cholesteatoma at various middle ear cleft subsites and bony relations, making it a valuable tool for surgical planning.

Recent advances in MRI of the head and neck, skull base and cranial nerves: new and evolving sequences, analyses and clinical applications

MRI is an invaluable diagnostic tool in the investigation and management of patients with pathology of the head and neck. However, numerous technical challenges exist, owing to a combination of fine anatomical detail, complex geometry (that is subject to frequent motion) and susceptibility effects from both endogenous structures and exogenous implants. Over recent years, there have been rapid developments in several aspects of head and neck imaging including higher resolution, isotropic 3D sequences, diffusion-weighted and diffusion-tensor imaging as well as permeability and perfusion imaging. These have led to improvements in anatomic, dynamic and functional imaging. Further developments using contrast-enhanced 3D FLAIR for the delineation of endolymphatic structures and black bone imaging for osseous structures are opening new diagnostic avenues. Furthermore, technical advances in compressed sensing and metal artefact reduction have the capacity to improve imaging speed and quality, respectively. This review explores novel and evolving MRI sequences that can be employed to evaluate diseases of the head and neck, including the skull base.

Cost-comparison analysis of diffusion weighted magnetic resonance imaging (DWMRI) versus second look surgery for the detection of residual and recurrent cholesteatoma

Background

Cholesteatoma is a destructive, erosive growth of keratinizing squamous epithelium in the middle ear cleft. Following treatment with a canal wall-up (CWU) tympanomastoidectomy, surveillance of residual and recurrent disease has traditionally been achieved through a second look tympanotomy following the initial procedure. Historically, MRI sequences have been inadequate at differentiating between granulation tissue, inflammation, and cholesteatoma. Recent literature has shown diffusion-weighted magnetic resonance imaging (DWMRI) to be a viable alternative to second look surgery for the detection of residual or recurrent disease. The goal of the present study was to perform a cost analysis of DWIMRI versus second look surgery in the detection of residual or recurrent cholesteatoma following combined approach tympanomastoidectomy.

Methods

A probabilistic decision tree model was generated from a literature review to compare traditional second look surgery with DWMRI. Cost inputs were obtained from the Ontario Case Costing Initiative, the Ontario Health Insurance Plan (OHIP) schedule of benefits. Costs were reported in Canadian dollars and a payer perspective was adopted. A probabilistic sensitivity analysis was performed.

Results

According to the probabilistic sensitivity analysis, mean cost difference of traditional second look tympanotomy versus echo planar imaging (EPI) DWMRI was $180.27CAD, 95%CI [$177.32, $188,32] in favour of second-look tympanotomy. However, mean cost difference of traditional second look tympanotomy versus non-EPI DWMRI was $390.66CAD, 95%CI [$381.52, $399.80] in favour of non-EPI DWMRI.

Conclusions

Diffusion-weighted MRI, specifically non-EPI sequences, are a viable cost-saving alternative to second-look tympanotomy in the setting of detecting residual or recurrent cholesteatoma.

Petrous bone cholesteatoma: our experience of 51 patients with emphasis on cochlea preservation and use of endoscope

Background: Petrous bone cholesteatoma (PBC) is a rare but local aggressive lesion which can lead to severe complications. Surgery is the mainstay for its treatment. Objectives: To analyse the clinical characteristics and surgical outcomes in a series of patients with PBC, paying special attention to cochlea preservation and use of endoscope. Materials and methods: Retrospective study of 51 patients with PBC who underwent surgery at our centre. Results: Hearing loss (72.5%) and facial paralysis (58.8%) were the two most common symptoms. According to Sanna's classification, supralabyrinthine subtype (51.0%) was the most common subtype, followed by the massive subtype (33.3%). In most patients, PBC was radically removed using subtotal petrosectomy (80.4%). Endoscope was used for assistance in six cases. Various managements of facial nerve were used in different cases. Hearing rehabilitation was not emphasized (44 postoperative dead ear); however, cochlea was preserved as far as possible (45.3%). Recurrence was identified in five patients by MRI with diffusion weighted imaging (DWI) sequence. No recurrence was detected in patients underwent surgery with endoscope assistance. Conclusions and significance: radical excision and functional reconstruction constitute the framework of PBC surgery. Cochlea preservation is critical for possible cochlear implantation in the future. Use of endoscope has the potential to enhance surgical precision and reduce recurrence.

The diagnostic accuracy of 1.5 T versus 3 T non-echo-planar diffusion-weighted imaging in the detection of residual or recurrent cholesteatoma in the middle ear and mastoid

PURPOSE AND BACKGROUND

This study retrospectively compares diagnostic performance of 1.5 T versus 3 T non-echo planar diffusion weighted imaging with or without additional T1 and T2 sequences in the detection of residual and/or recurrent cholesteatoma.

METHODS

Patients with clinically suspected recurrent cholesteatoma or postoperative routine survey MR who subsequently underwent surgical procedure were retrospectively included (135 patients, 164 operated ears) from a large database. Patients underwent 1.5 T (128 ears) or 3 T MRI (36 ears), with non-echo planar DWI, T1 and T2 acquisitions. Two radiologists independently reassessed the images. Definitive surgical diagnosis was used as gold standard. Sensitivity, specificity and diagnostic odds ratio were evaluated.

RESULTS

According to surgical diagnosis a cholesteatoma was present in 124 of 164 ears, corresponding with a prevalence of 75%. Sensitivity and specificity were lower for 3 T compared to 1.5 T, irrespective of whether additional T1 and T2-weighted sequences were used or not. Diagnostic odds ratios were higher for 1.5 T (34 and 12 for reader 1 and 2, respectively) compared to 3 T (3 and 4 for reader 1 and 2, respectively). Adding T1 and T2 sequences lowers sensitivity but increases specificity.

CONCLUSION

Non-epi DWI for the detection of residual/recurrent cholesteatoma is preferably performed on 1.5 T scanners over 3 T. The use of additional sequences regarding detection of cholesteatoma is debatable as it lowers sensitivity but increases specificity. However, these sequences may also be of use in diagnosing complications and planning surgical procedures in some hospitals.

Using Non-Echoplanar Diffusion Weighted MRI in Detecting Cholesteatoma Following Canal Wall Down Mastoidectomy - Our Experience with 20 Patient Episodes

OBJECTIVE

To our knowledge, there is no study exploring specifically the diagnostic performance of diffusion-weighted imaging (DWI) in patients with previous canal wall down (CWD) surgery when combined with appropriate clinical evaluation. The aim of the present study was to evaluate the performance of DWI in the detection of residual or recurrent disease in patients who have had a previous CWD mastoidectomy.

MATERIALS AND METHODS

We identified 13 patients with a CWD mastoidectomy subsequently having at least one further DWI prior to further mastoid exploration that generated a total of 20 patient episodes. Magnetic resonance imaging was performed on a 1.5 T superconductive unit using a standard head matrix coil. Coronal 2 mm thick TSE T2-weighted images (TR: 4640 ms; TE: 103 ms; matrix: 245,384; field of view: 150×200 mm) were performed. Operative findings were reviewed for all 20 patient episodes to compare DWI findings with intraoperative findings. Based on this, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated.

RESULTS

DWI had a sensitivity of 93%, specificity of 60%, PPV of 87%, NPV of 75%, and accuracy of 80%.

CONCLUSION

Given the high sensitivity of DWI in the detection of residual or recurrent disease, the present study supports DWI as a useful tool in the detection of residual or recurrent cholesteatoma in cases following CWD surgery, where clinical acumen suggests an ongoing disease process despite no overt cholesteatoma being visible.

Cholesteatoma vs granulation tissue: a differential diagnosis by DWI-MRI apparent diffusion coefficient

PURPOSE

To diagnose cholesteatoma when it is not visible through tympanic perforation, imaging techniques are necessary. Recently, the combination of computed tomography and magnetic resonance imaging has proven effective to diagnose middle ear cholesteatoma. In particular, diffusion weighted images have integrated the conventional imaging for the qualitative assessment of cholesteatoma. Accordingly, the aim of this study was to obtain a quantitative analysis of cholesteatoma calculating the apparent diffusion coefficient value. So, we investigated whether it could differentiate cholesteatoma from other inflammatory tissues both in a preoperative and in a postoperative study.

METHODS

This study included 109 patients with clinical suspicion of primary or residual/recurrent cholesteatoma. All patients underwent preoperative computed tomography and magnetic resonance imaging with diffusion sequences before primary or second-look surgery to calculate the apparent diffusion coefficient value.

RESULTS

We found that the apparent diffusion coefficient values of cholesteatoma were significantly lower than those of non cholesteatoma. In particular, the apparent diffusion coefficient median value of the cholesteatoma group (0.84 × 10^- 3 mm²/s) differed from the inflammatory granulation tissue (2.21 × 10^- 3 mm²/s) group (p < 2.2 × 10^- 16). Furthermore, we modeled the probability of cholesteatoma by means of a logistic regression and we determined an optimal cut-off probability value of ~ 0.86 (specificity = 1.0, sensitivity = 0.97), corresponding to an apparent diffusion coefficient cut-off value of 1.37 × 10^- 3 mm²/s.

CONCLUSIONS

Our study has demonstrated that apparent diffusion coefficient values constitute a valuable quantitative parameter for preoperative differentiation of cholesteatomas from other middle ear inflammatory diseases and for postoperative diagnosis of recurrent/residual cholesteatomas.

ADC Benchmark Range for Correct Diagnosis of Primary and Recurrent Middle Ear Cholesteatoma

OBJECTIVES

Magnetic resonance imaging (MRI) and in particular diffusion-weighted imaging (DWI) have been broadly proven to be the reference imaging method to discriminate between cholesteatoma and noncholesteatomatous middle ear lesions, especially when high tissue specificity is required. The aim of this study is to define a range of apparent diffusion coefficient (ADC) values within which the diagnosis of cholesteatoma is almost certain.

METHODS

The study was retrospectively conducted on a cohort of 124 patients. All patients underwent first- or second-look surgery because primary or secondary acquired cholesteatoma was clinically suspected; they all had preoperative MRI examination 15 days before surgery, including DWI from which the ADC maps were calculated.

RESULTS

Average ADC value for cholesteatomas was 859,4 × 10-6 mm2/s (range 1545 × 10-6 mm2/s; IQR = 362 × 10-6 mm2/s; σ = 276,3 × 10-6 mm2/s), while for noncholesteatomatous inflammatory lesions, it was 2216,3 × 10-6 mm2/s (range 1015 × 10-6 mm2/s; IQR = 372,75 × 10-6 mm2/s; σ = 225,6 × 10-6 mm2/s). Interobserver agreement with Fleiss' Kappa statistics was 0,96. No overlap between two groups' range of values was found and the difference was statistically significant for p < 0.0001.

CONCLUSIONS

We propose an interval of ADC values that should represent an appropriate benchmark range for a correct differentiation between cholesteatoma and granulation tissue or fibrosis of noncholesteatomatous inflammatory lesions.

Accuracy of turbo spin-echo diffusion-weighted imaging signal intensity measurements for the diagnosis of cholesteatoma

PURPOSE

We aimed to evaluate the diagnostic accuracy of turbo spin-echo diffusion-weighted imaging (TSE-DWI) at 3 T, for cholesteatoma (CS) diagnosis, using qualitative and quantitative methods with numerical assessment of signal intensity (SI), signal intensity ratios (SIR), and apparent diffusion coefficient (ADC) values.

METHODS

In this retrospective study, two blinded observers independently evaluated the preoperative TSE-DWI images of 57 patients who were imaged with a presumed diagnosis of CS. Qualitative assessment with respect to the SI of the adjacent cortex and quantitative measurements of SI, SIR, and ADC values were performed.

RESULTS

Surgery with histopathologic examination revealed 30 CS patients and 27 patients with non-cholesteatoma (NCS) lesions including chronic inflammation and cholesterol granuloma. On TSE-DWI, 96.7% of the CS lesions and none of the NCS lesions appeared hyperintense compared with the cortex. The mean SI and SIR indices of the CS group were significantly higher and the mean ADC values significantly lower compared with those of the NCS group (P < 0.001). Using specific cutoff values for SI (92.5) and SIR (0.9), CS could be diagnosed with 100% sensitivity and specificity. The use of quantitative imaging further increased the sensitivity of the TSE-DWI technique.

CONCLUSION

The quantitative indices of SI, SIR, and ADC of TSE-DWI appear to be highly accurate parameters that can be used to confirm the diagnosis of CS.

Does non-echo-planar diffusion-weighted magnetic resonance imaging have a role in assisting the clinical diagnosis of cholesteatoma in selected cases?

OBJECTIVE

To determine the diagnostic performance of diffusion-weighted magnetic resonance imaging in the assessment of patients with suspected, but not clinically evident, cholesteatoma.

METHODS

A retrospective analysis of a prospectively collected database of non-echo-planar diffusion-weighted magnetic resonance imaging studies (using a half-Fourier single-shot turbo-spin echo sequence) was conducted. Clinical records were retrospectively reviewed to determine indications for imaging and operative findings. Seventy-eight investigations in 74 patients with suspected cholesteatoma aged 5.7-79.2 years (mean, 41.7 years) were identified. Operative confirmation was available in 44 ears. Diagnostic accuracy of the imaging technique was calculated using operative findings as a 'gold standard'. Sensitivity of the investigation was examined via comparison with clinically evident cholesteatoma.

RESULTS

The accuracy of diffusion-weighted magnetic resonance imaging in assessment of suspected cholesteatoma was 63.6 per cent. The imaging technique was significantly less accurate in assessment of suspected cholesteatoma than clinically evident disease (p < 0.001).

CONCLUSION

Computed tomography and diffusion-weighted magnetic resonance imaging may be complementary in assessment of suspected cholesteatoma, but should be used with caution, and clinical judgement is paramount.

Diffusion weighted imaging for the detection and evaluation of cholesteatoma

Cholesteatoma is a collection of keratinous debris and stratified squamous epithelium. It is trapped in the middle ear and can lead to bony erosion. The disease is treated surgically often followed by a second-look procedure to check for residual tissue or recurrence. Cholesteatoma has specific signal-intensity characteristics on magnetic resonance imaging with very high signal intensity on diffusion weighted imaging (DWI). Various DWI techniques exist: Echo-planar imaging (EPI)-based and non-EPI-based techniques as well as new approaches like multi-shot EPI DWI. This article summarizes all techniques, discusses the significance in detecting cholesteatoma and mentions actual studies. Further recommendations for daily clinical practise are provided.

Update From the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumours of the Ear

The 2017 fourth edition of the World Health Organization Classification of Tumours, specifically as it relates to the ear (Chap. 9), has several changes. Importantly, the number of entities has been significantly reduced by omitting tumors or lesions if they do not occur exclusively or predominantly at this site or if they are discussed in detail elsewhere in the book. These entities include: embryonal rhabdomyosarcoma, osteoma, exostosis, angiolymphoid hyperplasia with eosinophilia, Schneiderian papilloma, inverted papilloma, lipoma of the internal auditory canal, hemangioma, hematolymphoid tumors, and secondary tumors. Paraganglioma was included in the neck chapter. New entries include otosclerosis and cholesteatoma, while refinements to nomenclature, classification and criteria were incorporated into the ceruminous gland tumors and epithelial tumors of the middle and inner ear. Specifically, the middle and inner ear were combined, as practical limitations of origin and imaging make a definitive separation artificial. The classification reflects the state of current understanding for these uncommon entities, with this update only highlighting selected entities that were the most significantly changed.

Repeated Postoperative Follow-up Diffusion-weighted Magnetic Resonance Imaging to Detect Residual or Recurrent Cholesteatoma

OBJECTIVE

In our institution, follow-up diffusion-weighted imaging (DWI) after cholesteatoma surgery is performed at least twice. The aim of this study was to determine the yield of the second follow-up DWI (D-W MRI-2) in patients in whom the first postoperative DWI (D-W MRI-1) was negative for residual or recurrent cholesteatoma.

STUDY DESIGN

A retrospective analysis.

SETTING

Tertiary referral center.

PATIENTS

Patients were included if 1) they had at least two postoperative DWI examinations after a canal wall up procedure with apparently complete cholesteatoma resection; 2) D-W MRI-1 was performed between 6 and 24 months after surgery and D-W MRI-2 performed at least 6 months after D-W MRI-1; 3) both DWI examinations were of good quality and covering the whole mastoid-middle ear region; 4) D-W MRI-1 was unequivocally negative for cholesteatoma; and 5) there was no clinical suspicion on otoscopy of recurrent cholesteatoma nor a surgical intervention between these two postoperative DWI examinations. In total, 45 separate ears in 44 patients were included.

RESULTS

In 14 ears (31%) D-W MRI-2 was positive (n = 8) or equivocal (n = 6) for cholesteatoma. In six of eight patients with positive D-W MRI-2, follow-up surgery was performed. Cholesteatoma was found in five of them. None of the patients with equivocal findings on D-W MRI-2 was operated on. Patients with positive D-W MRI-2 were of young age. There were no observable differences for sex, side, time between surgery and D-W MRI-1, time between surgery and D-W MRI-2, or time between D-W MRI-1 and D-W MRI-2, or for the location of cholesteatoma at surgery. In the study period there was a trend to perform D-W MRI-1 and D-W MRI-2 earlier after initial surgery. In the same period, there was an evident decrease in average age of the patient population.

CONCLUSION

Despite cholesteatoma surgery without macroscopic residue, clinical follow-up and routine first follow-up DWI without any signs of residual or recurrent disease, repeat follow-up DWI showed evidence of cholesteatoma in 31% of patients. On the basis of the findings in this study, repeated follow-up DWI is recommended.

Postoperative diffusion weighted MRI and preoperative CT scan fusion for residual cholesteatoma localization

OBJECTIVE

To evaluate the ability of preoperative mastoid high resolution Computerized tomography (CT Scan) fusion with the postoperative diffusion weighted magnetic resonance imaging (Non-EPI DWI) to accurately localize the residual cholesteatoma thus sparing an unnecessary postoperative CT scan radiation.

PATIENTS AND METHODS

this is a prospective study performed in our tertiary care center. We followed up prospectively a consecutive group of patients presenting with middle ear cholesteatoma using preoperative mastoid CT scans, postoperative mastoid CT scan and mastoid diffusion weighted MRI (DWI) between 2012 and 2013. Postoperative DWI were fused to both: the preoperative and postoperative mastoid CT scans. Fused images were evaluated for their ability to detect accurately the location of residual cholesteatoma if any. Results were correlated to the surgical findings.

RESULTS

Twenty-eight patients were included in this study. Ten patients showed middle ear opacity on the postoperative CT scans; the remaining negatively patients were excluded. DWI detected residual cholesteatoma in 3 out of the ten patients. Both CT scans; the pre and postoperative were able to precisely localize the residual cholesteatoma when fused to the postoperative DWI. Intra-operatively, three patients had a residual cholesteatoma that corresponded to the fused radiological images while a fourth patient presenting low signal intensity on the Non-EPI DWI had no cholesteatoma.

CONCLUSION

Diffusion weighted MRI/CT scan fusion combines the advantages of residual cholesteatoma detection and precise localization. Preoperative CT scans performed before the first surgery can be used for the fusion with the Non-EPI DWI in order to spare the patient an unnecessary another CT scan and thus decreasing radiation exposure.

Diffusion-Weighted Magnetic Resonance Imaging of Cholesteatoma Using PROPELLER at 1.5T: A Single-Centre Retrospective Study

PURPOSE

The purpose of this study was to evaluate the sensitivity, specificity, and positive and negative predictive values of the diffusion-weighted periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique in the detection of cholesteatoma at our institution with surgical confirmation in all cases.

METHODS

A retrospective review of 21 consecutive patients who underwent diffusion-weighted PROPELLER magnetic resonance imaging (MRI) on a 1.5T MRI scanner prior to primary or revision/second-look surgery for suspected cholesteatoma from 2009-2012 was performed.

RESULTS

Diffusion-weighted PROPELLER had a sensitivity of 75%, specificity of 60%, positive predictive value of 86%, and negative predictive value of 43%. In the 15 patients for whom the presence or absence of cholesteatoma was correctly predicted, there were 2 cases where the reported locations of diffusion restriction did not correspond to the location of the cholesteatoma observed at surgery.

CONCLUSION

On the basis of our retrospective study, we conclude that diffusion-weighted PROPELLER MRI is not sufficiently accurate to replace second look surgery at our institution.

Non-echoplanar diffusion weighted imaging in the detection of post-operative middle ear cholesteatoma: navigating beyond the pitfalls to find the pearl

Abstract

Non-echoplanar diffusion weighted magnetic resonance imaging (DWI) has established itself as the modality of choice in detecting and localising post-operative middle ear cleft cholesteatoma. Despite its good diagnostic performance, there are recognised pitfalls in its radiological interpretation which both the radiologist and otologist should be aware of. Our article highlights the various pitfalls and provides guidance for improving radiological interpretation and navigating beyond many of the pitfalls. It is recommended radiological practice to interpret the diffusion weighted images together with the ADC map and supplement with the corresponding T1 weighted and T2 weighted images, all of which can contribute to and enhance lesion localisation and characterisation. ADC values are also helpful in improving specificity and confidence levels. Given the limitation in sensitivity in detecting small cholesteatoma less than 3 mm, serial monitoring with DWI over time is recommended to allow any small residual cholesteatoma pearls to grow and become large enough to be detected on DWI. Optimising image acquisition and discussing at a joint clinico-radiological meeting both foster good radiological interpretation to navigate beyond the pitfalls and ultimately good patient care.

Teaching Points

• Non-echoplanar DWI is the imaging of choice in detecting post-operative cholesteatoma.

• There are recognised pitfalls which may hinder accurate radiological interpretation.

• Interpret with the ADC map /values and T1W and T2W images.

• Serial DWI monitoring is of value in detection and characterisation.

• Optimising image acquisition and discussing at clinico-radiological meetings enhance radiological interpretation.

The Efficacy of Color-Mapped Diffusion-Weighted Images Combined With CT in the Diagnosis and Treatment of Cholesteatoma Using Transcanal Endoscopic Ear Surgery

OBJECTIVE

To assess the efficacy of a color-mapped diffusion-weighted image combined with a computed tomography scan (CMDWI-CT) in preoperatively evaluating the anatomical location of cholesteatomas and determining whether a patient is indicated for transcanal endoscopic ear surgery (TEES) to reduce intraoperative switching to microscopic ear surgery (MES).

STUDY DESIGN

Prospective case study.

SETTING

A single university hospital.

PATIENTS

Fifty-five patients scheduled for middle ear cholesteatoma surgery.

INTERVENTION

The CMDWI-CT is produced in a multistep process. A color-mapped fusion image (CMFI) is created by performing MR cisternography on a 1-mm thin-slice nonecho planar diffusion-weighted imaging (non-EPI DWI) and then by performing color mapping on the resulting image to enhance cholesteatoma visualization. False positives are reduced by taking a T1-weighted image (T1WI), whereas false negatives are further reduced by preoperative endoscopic examination. As cholesteatomas are difficult to locate on a CMFI in the temporal bone region, we stripped out the MR cisternography data from the CMFI and then fused the CMFI to the initial computer tomography (CT) scan to create a CMDWI-CT. This CMDWI-CT better clarifies the cholesteatoma position within temporal bone.

MAIN OUTCOME MEASURE(S)

CMDWI-CT preoperative findings were compared with intraoperative findings. The positive predictive value and negative predictive value were also evaluated depending on the cholesteatoma location.

RESULTS

CMDWI-CT facilitated accurate detection of the cholesteatoma anatomical location in the temporal bone region which was reflected in positive predictive and negative predictive values of over 90% for all areas of the middle ear.

CONCLUSION

CMDWI-CT is a reliable diagnostic modality for evaluating the anatomical location of cholesteatomas that seem as high-signal regions on a CMFI and for determining whether TEES is indicated for treatment in such patients.