Comparing diffusion weighted MRI in the detection of post-operative middle ear cholesteatoma in children and adults

MRI-DWI detection of residual cholesteatoma: moving toward an optimum follow-up scheme

PURPOSE

To analyse diagnostic accuracy of MRI-DWI in detecting residual disease after cholesteatoma surgery and propose an optimum follow-up (FU) scheme.

METHOD

A retrospective chart review of patients who had cholesteatoma surgery in a tertiary referral centre. 3.0 T non-echo planar diffusion weighted imaging was performed as part of routine FU or indicated on the basis of clinical suspicion of disease. Imaging outcome was verified per-operatively during a second-look procedure or ossicular chain reconstruction. Diagnostic parameters were calculated and stratified by FU length.

RESULTS

For the FU of 664 cholesteatoma surgeries, 1208 MRI-DWI were obtained and 235 second-look procedures were performed. Most MRI-DWI were obtained within 1.5 yrs of surgery. In this period, significantly less true positive MRI-DWI and significantly more false negative MRI-DWI for residual disease were found compared to other FU periods. Scanning after approximately 3 yrs yielded a significantly higher rate of true positive MRI-DWI, while sensitivity surpassed 80%. Younger patients had a higher risk of developing residual disease. Patients undergoing canal wall up surgery, as well as patients < 12 yrs, were at risk for false negative MRI-DWI. Obliteration reduces the risk of residual disease, while leading to less false negative MRI-DWI.

CONCLUSION

A novel radiologic FU scheme for detecting residual disease is suggested for stable ears after cholesteatoma surgery: standard MRI-DWI approximately 3 and 5 yrs after primary surgery, as well as MRI-DWI after approximately 9 yrs for patients with specific risk factors (i.e., patients < 12 yrs or patients undergoing canal wall up surgery without obliteration).

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.

Performance of Non-EPI DW MRI for Pediatric Cholesteatoma Follow-Up

OBJECTIVE

To evaluate the accuracy, sensitivity, and specificity of nonecho planar (non-EPI) diffusion-weighted (DW) magnetic resonance imaging (MRI) to detect residual cholesteatoma in children.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary comprehensive hospital.

METHODS

Children operated on for a first-stage cholesteatoma procedure from 2010 to 2019 were included. MRIs were performed with non-EPI DW sequences. Initial reports were collected, indicating the presence or absence of hyperintensity suggestive of cholesteatoma. Three hundred twenty-three MRIs were correlated with the subsequent surgery (66%) or year-later MRI (21%), or were considered accurate if performed 5 years or more after the last surgery (13%). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging procedure for the detection of cholesteatoma were calculated.

RESULTS

Two hundred twenty-four children with mean age of 9 ± 4 years old presented with cholesteatoma. MRIs were performed 27 ± 24 months after surgery. Residual cholesteatoma was diagnosed in 35%. The sensitivity, specificity, PPV, and NPV of MRI were 62%, 86%, 74%, and 78%, respectively. Accuracy, sensitivity, and specificity increased significantly over time (multivariate analysis). The mean delay after last surgery was of 30 ± 2.0 months for accurate MRI (true positive or negative) versus 17 ± 2.0 months for nonaccurate (false positive or negative) MRIs (p < .001).

CONCLUSION

However, long the delay after the last surgery, the sensitivity of non-EPI diffusion sequence MRI in children has limitations for the detection of residual cholesteatoma. Surveillance for residual cholesteatoma should incorporate findings at primary surgery, surgeon experience, a low threshold for second-look procedures, and routine imaging.

Cholesteatoma surgery in the pediatric population: remaining challenges in the era of mastoid obliteration

PURPOSE

To present the first pediatric study on the safety and efficacy of mastoid obliteration using S53P4 bioactive glass (BAG) for cholesteatoma surgery.

METHODS

A single-center retrospective cohort study was conducted. Inclusion criteria were pediatric cases (≤ 18 years) and at least at least one year of follow-up including non-echo planar diffusion-weighted MRI to assess cholesteatoma recidivism. Both canal wall up (CWU) and canal wall down (CWD) procedures were evaluated.

RESULTS

A total of 61 cases (56 patients) were included. Most cases had an otologic history before the development of the cholesteatoma. CWU procedure was performed in 18 cases (30%) and CWD procedure in 43 cases (70%). The cholesteatoma recidivism rate was 33% after a mean follow-up period of 58 months. Kaplan-Meier curve estimated a 5-year recidivism rate of 40%. Few complications were seen that were all minor and resolved spontaneously or after local or systemic treatment. Control of the infection (merchant grade 0-1) was achieved in 98% of the cases. Closure of the air-bone gap within 20 dB was achieved in 22% of the cases with complete audiometric evaluation.

CONCLUSION

In this MRI-controlled study, we show the safety and efficacy of S53P4 BAG for mastoid obliteration in a pediatric cholesteatoma cohort. Postoperative complications were both rare and minor, and a dry ear was achieved in almost all patients. Nevertheless, persistent hearing loss and the apparent high recidivism rate reflect the challenging nature of pediatric cholesteatoma.

Non-echo Planar Diffusion-Weighted Imaging in the Detection of Recurrent or Residual Cholesteatoma: A Systematic Review and Meta-Analysis of Diagnostic Studies

We performed a systematic review and meta-analysis of patients with suspected recurrent cholesteatoma who underwent non-echo planar imaging (non-EPI) using diffusion-weighted magnetic resonance imaging (MRI), with surgery as the reference standard. We searched Medline, Google Scholar, and the Cochrane database for diagnostic test accuracy studies. The following prespecified subgroup analyses were performed: patient age, number of radiologists interpreting MRI, study design, and risk of bias. We used a bivariate model using a generalized linear mixed model to pool accuracies. Of the 460 records identified, 32 studies were included, of which 50% (16/32) were low risk of bias. The overall pooled sensitivity was 92.2% (95% CI 87.3-95.3%), and specificity was 91.7% (85.2-95.5%). The positive likelihood ratio was 11.1 (4.5-17.8), and the negative likelihood ratio was 0.09 (0.04-0.13). The pooled diagnostic odds ratio was 130.3 (20.5-240). Heterogeneity was moderate on visual inspection of the hierarchical summary receiver operating characteristic curve. Subgroup analyses showed prospective studies reporting higher accuracies (p=0.027), which were driven by higher specificity (prospective 93.1% (88.4-96.0%) versus retrospective 81.2% (81.0-81.4%)). There was no difference in subgroups comparing patient age (p=0.693), number of radiologists interpreting MRI (p=0.503), or risk of bias (p=0.074). No publication bias was detected (p=0.98). In conclusion, non-EPI is a highly sensitive and specific diagnostic test able to identify recurrent cholesteatomas of moderate to large sizes. This test can be considered a non-invasive alternative to second-look surgery.

Diffusion-weighted magnetic resonance imaging for diagnosis of post-operative paediatric cholesteatoma

OBJECTIVES

High rates of recidivism are reported after paediatric cholesteatoma surgery. Our practice has adapted to include non-echoplanar diffusion-weighted magnetic resonance imaging for the diagnosis of residual or recurrent cholesteatoma. This audit aimed to evaluate the performance of non-echoplanar diffusion-weighted magnetic resonance imaging in our paediatric population.

METHODS

A retrospective review was conducted of non-echoplanar diffusion-weighted magnetic resonance imaging scans performed to detect residual disease or recurrence after surgery for cholesteatoma in children from 1 January 2012 to 30 November 2017 in our centre. Follow-up diffusion-weighted magnetic resonance imaging scans were reviewed to 16 August 2019.

RESULTS

Thirty-four diffusion-weighted magnetic resonance imaging scans were included. The sensitivity and specificity values of diffusion-weighted magnetic resonance imaging for detecting post-operative cholesteatoma were 81 per cent and 72 per cent, respectively. Positive predictive and negative predictive values were 72 per cent and 81 per cent, respectively.

CONCLUSION

Use of diffusion-weighted magnetic resonance imaging is recommended as a replacement for routine second-look surgical procedures in the paediatric population. However, we would caution that patients require close follow up after negative diffusion-weighted magnetic resonance imaging findings.

Guidelines for magnetic resonance imaging in pediatric head and neck pathologies: a multicentre international consensus paper

The use of standardized imaging protocols is paramount in order to facilitate comparable, reproducible images and, consequently, to optimize patient care. Standardized MR protocols are lacking when studying head and neck pathologies in the pediatric population. We propose an international, multicenter consensus paper focused on providing the best combination of acquisition time/technical requirements and image quality. Distinct protocols for different regions of the head and neck and, in some cases, for specific pathologies or clinical indications are recommended. This white paper is endorsed by several international scientific societies and it is the result of discussion, in consensus, among experts in pediatric head and neck imaging.

The Role of Fusion Technique of Computed Tomography and Non-echo-planar Diffusion-weighted Imaging in the Evaluation of Surgical Localization of Cholesteatoma

Objective:

In recent years, the fusion of computed tomography (CT) and non-echo-planar diffusion-weighted magnetic resonance imaging (non- EPI DWI) has been preferred in cholesteatoma localizations. This study aimed to investigate the role of CT and non-EPI DWI fusion imaging in cholesteatoma localizations.

Methods:

This retrospective study included 39 patients who underwent chronic otitis media operation [mean age of 35.10±15.33 years (18-67 years), 64.1% female, and 35.9% male] and had preoperative high-resolution temporal bone CT and non-EPI DWI examinations. Images were sent to the Advantage Workstation VolumeShare 7 for fusion. These selected images were fused on the workstation and were manually corrected by the radiologist. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracies of fused images of CT and non-EPI DWI were evaluated according to anatomic cholesteatoma localizations based on surgical data.

Results:

The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracies of non-EPI DWI for detecting cholesteatomas were 97.14%, 75.00%, 97.14%, 75.00%, and 94.87%, respectively. Three true-negative, one false-positive, and one false-negative case were observed according to surgical results in detecting the presence of a cholesteatoma with non-EPI DWI. Moderate agreement was determined between the surgical and radiological results in detecting the presence of a cholesteatoma (k=0.721). Detecting the lesion of localization on the fused images compared to surgical found an almost perfect agreement in the mastoid antrum (k=0.948), strong agreement in the hypotympanum and mastoid cells (k=0.894), moderate agreement in the epitympanum (k=0.653), and weak agreement in those in the mesotympanum (k=0.540).

Conclusions:

The surgeons’ determinations are supported by the guidance of temporal CT and non-EPI DWI fused images. Therefore, preferring the fusion imaging technique could increase the quality of life by reducing unnecessary operations.

[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.

Survey of the Use of Diffusion-Weighted Imaging for Cholesteatoma in the United Kingdom

BACKGROUND

Non-echoplanar diffusion-weighted MRI (DWMRI) has a role in the surgical planning for cholesteatoma.

AIMS/OBJECTIVES

The aim of the study was to assess the use of DWMRI in the management of cholesteatoma across the UK, and measure clinicians' confidence in the use of DWMRI.

MATERIALS AND METHODS

Telephone survey in 139 Otolaryngology Departments in the United Kingdom between March 2017 and July 2017, and asking radiology delegates at the British Society of Head and Neck Imaging 2017 meeting.

RESULTS

The response rate was 101 out of 139 Trusts (73%). Of those respondents who did have DWMRI available, 68/88 respondents (77%) use it for cholesteatoma. The mean confidence (±standard deviation) of the respondents with DWMRI in identifying cholesteatoma presence was 7.3 ± 2.1, in identifying volume of cholesteatoma was 6.8 ± 1.8, and in identifying subsites of cholesteatoma was 4.6 ± 2.1.

CONCLUSIONS AND SIGNIFICANCE

DWMRI has a well-defined role in the follow-up of patients after cholesteatoma surgery, and those primary cases of cholesteatoma where the diagnosis is in question. The use of DWMRI for cholesteatoma is variable across the UK, but there are certain clinical scenarios where there is not enough awareness regarding the benefits of imaging (such as petrous apex cases of cholesteatoma).

Silastic sheeting in staged ear surgery: Is there still a role for this procedure?

OBJECTIVE

To review long-term outcomes for chronic otitis media with and without cholesteatoma in staged canal-wall-up tympanoplasty with temporary silastic sheeting and to compare hearing and recurrence results with the literature.

METHODS

Retrospective data analysis of all patients suffering from chronic otitis media with or without cholesteatoma (COMC/COM) and treated by staged canal-wall-up (CWU) technique with silastic insertion between 1992 and 2012. Literature analysis in PubMed 1990-2017.

RESULTS

74 cases were included in the analysis. In COMC (n = 47) a total of 2 (4%) recurrent and 14 (30%) residual cholesteatoma were documented. The postoperative hearing test showed a pure-tone-average (PTA) of 36 dB hearing level (HL) and an air-bone-gap (ABG) of 21 dB HL. A significant improvement was only observed for stage I disease (PTA 8 dB HL and ABG 9 dB HL). In COM (n = 27) postoperative PTA and ABG were significantly improved by 33 dB HL and 23 dB HL, respectively. Mean postoperative follow-up was 47 months (12-173) for COMC and 22 months (2-120) for COM.

CONCLUSIONS

The cholesteatoma recurrence rate in this study reflects contemporary published rates. Assessment of hearing outcome is difficult due to the low number of cases and very high heterogeneity of published data. Still, the staged CWU procedure with temporary silastic sheeting seems to bear some advantages in regard to hearing. The role of additional factors such as Eustachian Tube function to assess outcome should be considered. An internationally agreed upon reporting system should be followed, if various surgical approaches are to be compared.

LEVEL OF EVIDENCE

3.

Positive predictive value for diffusion-weighted magnetic resonance imaging in pediatric cholesteatoma: A retrospective study

OBJECTIVES

The aims of this study were first to calculate the Positive Predictive Value (PPV) of DW-MRI to detect cholesteatoma and then to analyze false positives.

METHODS

All temporal bone MRI with DWI sequences performed in our pediatric university hospital between 2005 and 2015 were included retrospectively. 46 patients with a cholesteatoma diagnosis on the MRI report and who underwent surgery were studied.

RESULTS

The number of DW-MRI for identification of cholesteatoma has grown in ten years. We calculated an 89% Positive Predictive Value. DW-MRI sensitivities were 100.0% and 70.7% for respectively keratin and squamous epithelium.

CONCLUSION

DW-MRI hypersignal is not synonymous of cholesteatoma diagnosis. Indeed, this diagnosis relies on the importance of a proper otoscopic examination, a suggestive medical history, CT scan data and analysis of other MRI sequences, including T1-weighted sequence, to rule out other etiologies of middle ear DW-MRI hypersignal.

Novel Radiologic Approaches for Cholesteatoma Detection: Implications for Endoscopic Ear Surgery

Technological advancement in computed tomography (CT) and MRI has improved cholesteatoma detection rates considerably in the past decade. Accurately predicting disease location and extension is essential for staging, planning, and preoperative counseling, in particular in the newer approach of endoscopic ear surgery. Improved sensitivity and specificity of these radiological methods may allow the surgeon to confidently monitor patients, therefore avoiding unnecessary surgery. This article outlines recent advances in CT and MRI technology and advantages and disadvantages of the newer techniques. Emphasis on improving the feedback loop between the radiologist and surgeon will increase the accuracy of these new technologies.

Rapid diffusion-weighted MRI for the investigation of recurrent temporal bone cholesteatoma

BACKGROUND

Suspected cholesteatoma recurrence is commonly investigated with magnetic resonance imaging (MRI) of the temporal bone. Non-echo planar diffusion-weighted imaging (non-EP DWI) has become the sequence of choice.

PURPOSE

To assess the agreement between an MRI protocol incorporating both non-EP DWI and contrast-enhanced sequences, and a shortened protocol without contrast-enhanced sequences in the assessment of suspected cholesteatoma recurrence.

MATERIALS AND METHODS

One hundred consecutive MRIs, consisting of T2-weighted, non-EP DWI and pre- and post-contrast T1-weighted sequences, were reviewed by two radiologists at a tertiary referral centre. Agreement between the two protocols was assessment by means of a weighted Cohen kappa coefficient.

RESULTS

We found a near perfect agreement between the two protocols (kappa coefficient with linear weighting 0.98; 95% confidence interval 0.95-1.00). There were two cases in which the two protocols were discordant. In both cases, the lesion measured <3 mm and images were degraded by artefact at the bone-air interface. The shortened protocol without post-contrast sequences yielded a 32% reduction in acquisition time.

CONCLUSION

When non-EP DWI is available, contrast-enhanced sequences can be omitted in the vast majority of cases without compromising diagnostic accuracy. Contrast-enhanced sequences may provide additional value in equivocal cases with small (<3 mm) lesions or in cases where images are degraded by artefact.

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.

Value of DW-MRI in the preoperative evaluation of congenital cholesteatoma

OBJECTIVE

This study evaluated the clinical value of diffusion-weighted magnetic resonance imaging (DW-MRI) in the diagnosis and staging of congenital cholesteatoma (CC).

PATIENTS AND METHODS

We retrospectively reviewed 24 patients with CC. All the patients underwent computed tomography (CT) and DW-MRI preoperatively; thereafter, surgery was performed. DW-MRI examination was performed with a 3 T MRI system using three-dimensional reversed fast imaging with steady-state precession and diffusion-weighted magnetic resonance sequence. The preoperative and operative CT and DW-MRI findings were compared.

RESULTS

Using DW-MRI, cholesteatoma was successfully detected in 17 (71%) of the 24 patients with CC. Among the seven patients with false-negative results, the cholesteatoma mass diameter was <5 mm in six patients and ≥5 mm in one patient. One of these patients had open type congenital cholesteatoma (OTCC). The detection rates for closed type cholesteatoma and OTCC were 85% (17/20) and 0% (0/4), respectively, using DW-MRI. Using CT and DW-MRI, the correct stage was identified in 88% (15/17) and 59% (10/17) of the patients with aeration around the CC and in 0% (0/7) and 100% (7/7) of those without aeration around the CC, respectively.

CONCLUSION

CT is the primary imaging tool for evaluating suspected CC in patients with aeration around the CC. However, CT is unreliable for the detection of the extension and staging of CC when the middle ear is filled with nonspecific imaging. DW-MRI is useful for the preoperative diagnosis and staging of CC > 5 mm in diameter with or without surrounding granulation tissue. Thus, we recommend using DW- MRI at least when CT fails to localize CC as a soft tissue mass because of non-specific tissue filling the middle ear and the mastoid.

Diffusion-weighted magnetic resonance imaging in the detection of residual and recurrent cholesteatoma in children: A systematic review and meta-analysis

OBJECTIVE

To examine the performance of diffusion-weighted magnetic resonance imaging (DW-MRI) in the detection of residual and recurrent cholesteatoma in children.

METHODS

A systematic review and meta-analysis was conducted as per PRISMA guidelines using the following databases from their date of inception: MEDLINE, PubMed, Embase, Cochrane Library, Web of Science. Bivariate meta-analysis using a random effects model was used to calculate summarized pooled estimates of sensitivity, specificity, and diagnostic odds ratios, using second-look surgery as the gold standard comparison.

RESULTS

A total of ten articles (141 cases) were included for qualitative and quantitative analysis. Pooled sensitivity and specificity of non-echo planar imaging (non-EPI) DW-MRI were 89.4% (95%CI 51.9%-98.5%) and 92.9% (95%CI 81.4%-97.5%) respectively. DW-MRI appears limited in its ability to detect lesions less than 3 mm in size.

CONCLUSION

Non-EPI DW-MRI is highly specific but carries uncertain sensitivity in the detection of residual and recurrent cholesteatoma in children. Further research is warranted to determine the specific role of DW-MRI in this patient group, namely when and how often children should be referred for imaging and in which cases the method can be used to completely replace second-look surgery.

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.

Monitoring Progression of 12 Cases of Non-Operated Middle Ear Cholesteatoma With Non-Echoplanar Diffusion Weighted Magnetic Resonance Imaging: Our Experience

AIM

The aim of this study is to gain insight into the disease progression and behavior of primary cholesteatoma in a cohort of patients who did not have surgery using non-echoplanar diffusion-weighted magnetic resonance imaging (DW MRI) serial monitoring.

METHODS

Retrospective longitudinal observational study of 12 cases of middle ear cleft cholesteatoma diagnosed between 2009 and 2014 where surgery was not performed for various reasons. All cases were monitored radiologically with non-echoplanar half-Fourier acquisition single-shot turbo spin-echo diffusion weighted imaging annually for a median period of 23 months (between 11 and 45 mo) to evaluate for changes in disease volume and direction of growth.

RESULTS

Of the 12 cases, there was one outlier where the cholesteatoma growth was disproportionately high compared with the rest of the cases outside the standard deviation range. A third of the cases had radiological evidence of cholesteatoma growth. The mean growth was about 11.9% of the initial disease volume per year. Seven out of the 12 cases had radiological evidence of cholesteatoma regression in terms of size, with three cases having negative follow-up DW-MRI scans as early as 17 months. The mean regression rate was much higher than the mean growth rate at 54.3% of the initial disease volume per year. The direction of greatest growth is craniocaudally.

CONCLUSION

Within the limits of our longitudinal study, we have shown that by monitoring with non-echoplanar diffusion weighted imaging, cholesteatoma can progress or regress when left untreated by surgery. The greatest progression was recorded in the craniocaudal direction.

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.