The diagnostic accuracy of non-echo-planar diffusion-weighted imaging in the detection of residual and/or recurrent cholesteatoma of the temporal bone

Comprehensive Management of Cholesteatoma in Otitis Media: Diagnostic Challenges, Imaging Advances, and Surgical Outcome

Background: This study presents a comprehensive analysis of cholesteatoma of the middle ear, focusing on its clinical presentation, diagnostic imaging, and treatment outcomes. Cholesteatomas are defined by the keratinized squamous epithelium within the middle ear, leading to significant bone erosion, often affecting the ossicular chain and surrounding structures. Methods: The study explores various mechanisms involved in cholesteatoma progression, including enzymatic lysis, inflammatory responses, and neurotrophic disturbances. The study conducted a retrospective clinical and statistical review of 580 patients over a 20-year period (2003-2023), highlighting the role of advanced imaging, including computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DWI), in preoperative planning and postoperative follow-up. Results: Findings revealed that early detection and intervention are crucial in preventing severe complications such as intracranial infection and hearing loss. Surgical treatment primarily involved tympanoplasty and mastoidectomy, with a recurrence rate of 1.55% within two years. The study underscores the importance of integrating imaging advancements into clinical decision-making to enhance patient outcomes and suggests further investigation into molecular mechanisms underlying cholesteatoma progression and recurrence. Histopathological and microbiological analysis was performed to identify pathological patterns and microbial agents. Conclusions: The study highlights the importance of early diagnosis and intervention to prevent complications such as intracranial infections and permanent hearing loss, while also emphasizing the role of advanced imaging techniques in the management and long-term monitoring of cholesteatoma patients.

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.

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.

PROPELLER diffusion weighted imaging for diagnosis of cholesteatoma in comparison with surgical and histopathological results: emphasis on false positivity and false negativity

PURPOSE

To investigate the role of non-echo planar diffusion weighted imaging (DWI) using "periodically rotated overlapping parallel lines with enhanced reconstruction" (PROPELLER) sequence for the diagnosis of cholesteatoma compared to surgical and histopathological results in an attempt to determine the factors causing false negative and false positive diagnoses.

METHODS

Patients who had PROPELLER DWI before ear surgery were retrospectively reviewed. The presence of a lesion with diffusion restriction on PROPELLER DWI was accepted as positive for cholesteatoma, and the results were compared to the intraoperative and histopathological findings.

RESULTS

A total of 112 ears in 109 patients were reviewed. On PROPELLER DWI, a lesion with diffusion restriction was found in 101 (90.2%) ears, while in 11 (9.8%) of the patients, no diffusion restriction was found. Surgery and histopathological analysis revealed a cholesteatoma in 100 (89.3%) ears, while in 12 (10.7%) ears, no cholesteatoma was found surgically. There were 96 (85.7%) true positives, 7 (6.2%) true negatives, 5 (4.5%) false positives and 4 (3.6%) false negatives. The accuracy, sensitivity, specificity, positive predictive and negative predictive values of non-echo planar DWI were calculated to be 91.96%, 96%, 58.33%, 95.05%, and 63.64%, respectively.

CONCLUSION

Non-echo planar DWI using PROPELLER sequence has high accuracy, sensitivity and positive predictive value and can be used for the detection of cholesteatoma. The external auditory canal, postoperative ears and small lesions should be evaluated with caution to avoid false results.

Quality-of-Life Outcomes After Modified Subtotal Petrosectomy With Ear Canal Closure for Chronic Otitis Media

OBJECTIVE

To assess quality-of-life (QoL) outcomes after modified subtotal petrosectomy with ear canal closure (mSTP) for chronic otitis media.

STUDY DESIGN

Survey study.

SETTING

Tertiary referral center.

PATIENTS

Patients with chronic otitis media.

INTERVENTIONS

mSTP.

MAIN OUTCOME MEASURES

Survey results from enrolled patients on the validated disease-specific Chronic Ear Survey (CES) and Chronic Otitis Media Outcome Test-15 (COMOT-15) regarding their current state of health and, if surgery was performed within 3 years of enrollment, their state of health before mSTP.

RESULTS

A total of 23 patients were studied, including 19 who underwent surgery within 3 years of enrollment. Postoperatively, mean total CES scores were 80 and COMOT-15 scores were 41, with a higher CES and a lower COMOT-15 indicating better QoL. There were statistically significant improvements after mSTP in the CES activity restriction (25% difference; p = 0.008), symptom (17% difference; p = 0.007), and medical resource (13% difference; p = 0.03) domain and total (18% difference; p = 0.006) scores. In addition, there were statistically significant improvements in the COMOT-15 ear symptom (-22% difference; p < 0.001) domain and total (-16% difference; p = 0.01) scores; however, improvements in the hearing function and mental health domains did not achieve statistical significance. Postoperative COMOT-15 total scores were significantly better for patients who underwent aural rehabilitation compared to those who did not (-17% difference; p < 0.001).

CONCLUSION

Modified subtotal petrosectomy with ear canal closure is a useful intervention for patients with recalcitrant chronic otitis media, offering improved QoL in appropriately selected patients. Aural rehabilitation, when feasible, provides the potential for further QoL improvement.

Outcome of Canal Wall Down Mastoidectomy: A Retrospective Review

A canal wall down mastoidectomy (CWDM) is an effective technique for eradication of chronic suppurative otitis media (atticoantral disease) or cholesteatomas. A retrospective study was conducted at R.D. Gardi Medical college between 2015 and 2017 to evaluate the outcome of CWDM for patients with atticoantral type of CSOM. All new cases of MRM/RM which fulfilled the selection criteria were reviewed. The main outcome measures were the hearing outcome and status of dry ear postoperatively. 60 patients of CWDM (32 male, 28 female) were included for analysis. All patients in our study were between 7 and 52 years with mean age 28.38 years. The ossicular chain was eroded in all the cases. Improvement in Air-Bone-Gap was seen in 11 (18.33%), no change in 38 (63.33%) and 11 (18.33%) had deteriorated. In post operative outcome study of our 60 patients, 76.66% of the patients had dry healed cavity and non healed cavity was found to be in 23.33% of the patients. On analysis of data and comparison with other studies it was found that there are three important factors which influence hearing results and the outcome of surgery-status of ossicular chain, presence or absence of cholesteatoma, recurrence or residual disease.

New and Advanced Magnetic Resonance Imaging Diagnostic Imaging Techniques in the Evaluation of Cranial Nerves and the Skull Base

The skull base and cranial nerves are technically challenging to evaluate using magnetic resonance (MR) imaging, owing to a combination of anatomic complexity and artifacts. However, improvements in hardware, software and sequence development seek to address these challenges. This section will discuss cranial nerve imaging, with particular attention to the techniques, applications and limitations of MR neurography, diffusion tensor imaging and tractography. Advanced MR imaging techniques for skull base pathology will also be discussed, including diffusion-weighted imaging, perfusion and permeability imaging, with a particular focus on practical applications.

Comparison of Readout-Segmented Echo-Planar Imaging and Single-Shot TSE DWI for Cholesteatoma Diagnostics

BACKGROUND AND PURPOSE

The high diagnostic value of DWI for cholesteatoma diagnostics is undisputed. This study compares the diagnostic value of readout-segmented echo-planar DWI and single-shot TSE DWI for cholesteatoma diagnostics.

MATERIALS AND METHODS

Thirty patients with newly suspected cholesteatoma were examined with a dedicated protocol, including readout-segmented echo-planar DWI and single-shot TSE DWI at 1.5T. Acquisition parameters of both diffusion-weighted sequences were as follows: b=1000 s/mm,² axial and coronal section orientations, and section thickness of 3 mm. Image quality was evaluated by 2 readers on a 5-point Likert scale with respect to lesion conspicuity, the presence of susceptibility artifacts mimicking cholesteatomas, and overall subjective image quality. Sensitivity and specificity were calculated using histology results as the gold standard.

RESULTS

Twenty-five cases of histologically confirmed cholesteatomas were included in the study group. Lesion conspicuity was higher and fewer artifacts were found when using TSE DWI (both P < .001). The overall subjective image quality, however, was better with readout-segmented DWI. For TSE DWI, the sensitivity for readers 1 and 2 was 92% (95% CI, 74%-99%) and 88% (95% CI, 69%-97%), respectively, while the specificity for both readers was 80% (95% CI, 28%-99%). For readout-segmented DWI, the sensitivity for readers 1 and 2 was 76% (95% CI, 55%-91%) and 68% (95% CI, 46%-85%), while the specificity for both readers was 60% (95% CI, 15%-95%).

CONCLUSIONS

The use of TSE DWI is advisable for cholesteatoma diagnostics and preferable over readout-segmented DWI.

T-staging of rectal cancer: Utility of single-shot turbo spin-echo diffusion-weighted imaging with T2-weighted images and fusion images

PURPOSE

The purpose of this study was to evaluate the usefulness of turbo spin-echo (TSE) DWI with fusion images in the T-staging compared with T2-weighted imaging (T2WI) alone and conventional echo-planner imaging (EPI) DWI.

METHODS

In this prospective study, 4-mm-thick axial EPI-DWI, TSE-DWI, and T2WI were performed with the same slice locations for 20 patients with rectal cancer. Fusion images of DWI and T2WI were created for both EPI-DWI and TSE-DWI. Ten readers independently diagnosed the T-stages and scored the degree of confidence referring to T2WI alone and then to DWI, T2WI, and fusion images (DWI+T2WI) for each EPI-DWI and TSE-DWI. Visual score assessments of image quality were performed for each DWI.

RESULTS

Inter-observer agreement of T-staging for 10 readers was slight on T2WI alone but fair on EPI-DWI+T2WI and excellent on TSE-DWI+T2WI images. No readers gave higher confidence scores for T2WI compared to EPI/TSE-DWI+T2WI and for EPI-DWI+T2WI compared to TSE-DWI+T2WI. In seven pathologically-proven cases, poor, poor to slight, and fair to perfect agreements with the pathological T-stage were observed with T2WI alone, EPI-DWI+T2WI, and TSE-DWI+T2WI, respectively. All readers gave higher scores regarding image distortion and lower scores regarding image noise for TSE-DWI compared to EPI-DWI. For DWI utility, higher scores were assigned for TSE-DWI compared to EPI-DWI in 7 readers and there were no significant differences in the other 3 readers.

CONCLUSION

TSE-DWI images might be more appropriate for image fusion with T2WI and rectal cancer T-staging compared with EPI-DWI and T2WI alone.

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.

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.

Technical Improvements in Head and Neck MR Imaging: At the Cutting Edge

Head and neck MR imaging is technically challenging because of magnetic field inhomogeneity, respiratory and swallowing motion, and necessity of high-resolution imaging to trace key anatomic structures. These challenges have been answered by advances in MR imaging technology, including isovolumetric three-dimensional imaging, robust fat-water separation techniques, and novel deep learning-based reconstruction algorithms. New applications of MR imaging have been advanced and functional imaging has been improved. Improvements in acquisition and reconstruction technique facilitate novel applications of morphologic and functional imaging. This results in opportunities to improve diagnosis, staging, and treatment selection through application of advanced MR imaging techniques.

Diffusion MR Imaging in the Head and Neck: Principles and Applications

Diffusion imaging is a functional MR imaging tool that creates tissue contrast representative of the random, microscopic translational motion of water molecules within human body tissues. Long considered a cornerstone MR imaging sequence for brain imaging, diffusion-weighted imaging (DWI) increasingly is used for head and neck imaging. This review reports the current state of diffusion techniques for head and neck imaging, including conventional DWI, DWI trace with apparent diffusion coefficient map, diffusion tensor imaging, intravoxel incoherent motion, and diffusion kurtosis imaging. This article describes background physics, reports supportive evidence and potential pitfalls, highlights technical advances, and details practical clinical applications.

Negative Predictive Value of Non-Echo-Planar Diffusion Weighted MR Imaging for the Detection of Residual Cholesteatoma Done at 9 Months After Primary Surgery Is not High Enough to Omit Second Look Surgery

OBJECTIVES

To evaluate non echo-planar diffusion weighted magnetic resonance imaging (non-EP DW MRI) at 9 months after primary surgery to rule out residual cholesteatoma in patients scheduled before second-look-surgical exploration.

STUDY DESIGN

Prospective observational study.

SETTING

Secondary teaching hospital.

PATIENTS/INTERVENTIONS

Patients who were scheduled for second-look-surgery after primary canal wall up repair of cholesteatoma underwent 1.5 T MRI including non-EP DWI and high-resolution coronal T1 and T2-FS SE sequences.

MAIN OUTCOME MEASURES

Imaging studies were evaluated for the presence of cholesteatoma by three independent observers. Intraoperative observations were regarded the standard of reference. Ear, nose, throat (ENT) surgeons were blinded for imaging findings. The primary outcome was the negative predictive value (NPV) of MR imaging, secondary outcomes were sensitivity, specificity, and positive predictive value.

RESULTS

Thirty-three patients underwent both MRI and surgery, among whom 22 had a cholesteatoma. Mean time between primary surgery and MRI was 259 days (standard deviation [SD] 108). NPV of non-EP DW MRI in detecting recurrent cholesteatoma was 53% (95% CI: 32-73%). Sensitivity and specificity were 59% (39-77%) and 91% (62-98%), respectively. The positive predictive value was 93% (69-99%). In five out of nine false-negative cases, recurrent cholesteatoma measured 3 mm or less. Using a 3 mm detection threshold, NPV increased to 79%.

CONCLUSION

Non-EP DW MRI cannot replace second look surgery in ruling-out residual cholesteatoma at 9 months after primary surgery. It could be used in a follow-up strategy in low risk patients. Further research is needed which types of residual cholesteatoma are not revealed by MRI.

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.

Apparent diffusion coefficients for predicting primary cholesteatoma risk of recurrence after surgical clearance

PURPOSE

Beside the well-known accuracy of non-EPI DWI techniques and relative ADC maps in detecting cholesteatomatous tissue, ADC can also represent a useful tool for stratifying cholesteatoma risk of recurrence. Aim of this study is to test the role of ADC in determining risk of recurrence for primary middle ear cholesteatoma, proposing stratification based on pre-operative mean (mADC) and normalized (nADC) ADC values.

METHODS

In this prospective study, 60 patients with primary unilateral middle ear cholesteatoma underwent a three-years-long follow-up to assess the presence of recurrent disease after macroscopically complete excisional surgery. Baseline MRI examination mADC and nADC values in the group with early evidence of recurrent cholesteatoma were compared to the group with no evidence of recurrence by using T statistics.

RESULTS

ADC values on pre-operative MRI examination were lower in cholesteatomas with early evidence of recurrence, and statistical significance was slightly higher for nADC compared to mADC measurements. We also determined a cut-off between the two groups, proposing stratification in high-risk of recurrence cholesteatomas (mADC≤ 1000 or nADC< 1.3) and low-risk cholesteatomas (mADC>1000 or nADC≥1.3).

CONCLUSIONS

ADC values resulted discriminating in identifying cholesteatomas with higher risk of early recurrence, both for mean and normalized ADC, with optimized tissue characterization and outcome prediction.

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.

Identification of risk factors for residual cholesteatoma in children and adults: a retrospective study on 110 cases of revision surgery

Introduction

Residual disease after cholesteatoma removal is still a challenge for the otorhinolaryngologist. Scheduled “second-look” surgery and, more recently, radiological screenings are used to identify residual cholesteatoma as early as possible. However, these procedures are cost-intensive and are accompanied by discomfort and risks for the patient.

Objective

To identify anamnestic, clinical, and surgery-related risk factors for residual cholesteatoma.

Methods

The charts of 108 patients, including children as well as adults, having undergone a second-look or revision surgery after initial cholesteatoma removal at a tertiary referral hospital, were analyzed retrospectively.

Results

Gender, age, mastoid pneumatization, prior ventilation tube insertion, congenital cholesteatoma, erosion of ossicles, atticotomy, resection of chorda tympani, different reconstruction materials, and postoperative otorrhea did not emerge as statistically significant risk factors for residual disease. However, prior adenoid removal, cholesteatoma growth to the sinus tympani and to the antrum and mastoid, canal-wall-up 2 ways approach, and postoperative retraction and perforation were associated with a statistically higher rate of residual disease. A type A tympanogram as well as canal-wall-down plus reconstruction 2 ways approach for extended epitympanic and for extended epitympanic and mesotympanic cholesteatomas were associated with statistically lower rates of residual disease. A score including the postoperative retraction or perforation of the tympanic membrane, the quality of the postoperative tympanogram and the intraoperative extension of the cholesteatoma to the sinus tympani and/or the antrum was elaborated and proved to be suitable for predicting residual cholesteatoma with acceptable sensitivity and high specificity.

Conclusion

Cholesteatoma extension to the sinus tympani, antrum and mastoid makes a residual disease more likely. The canal-wall-down plus reconstruction 2 ways approach seems safe with similar rates of residual cholesteatoma and without the known disadvantages of canal-wall-down surgery. The described score can be useful for identifying patients who need a postoperative radiological control and a second-look surgery.

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.

Cholesteatoma: multishot echo-planar vs non echo-planar diffusion-weighted MRI for the prediction of middle ear and mastoid cholesteatoma

Objective

We aimed to compare a newer readout-segmented echoplanar imaging (RS-EPI) technique with the established single shot turbo spin echo (SS-TSE) non-EPI diffusion-weighted imaging (DWI) in detecting surgically validated cholesteatoma.

Methods

We retrospectively reviewed 358 consecutive MRI studies in 285 patients in which both RS-EPI and non-EPI DWI sequences were performed. Each diffusion sequence was reviewed independently and scored negative, indeterminate or positive for cholesteatoma in isolation and after reviewing the T ₁W sequence. Average artefacts scores were evaluated and the lesion size measured as a distortion indicator. The imaging scores were correlated with surgical validation, clinical and imaging follow-up.

Results

There were 239 middle ear and central mastoid tract and 34 peripheral mastoid lesions. 102 tympanomastoid operations were performed. The positive predictive value ( PPV), post-operative PPV, primary PPV, negative predictive value were 93%, 95%, 87.5%, 70% for RS-EPI and 92.5%, 93.6%, 90%, 79% for non-EPI DWI. There was good agreement between the two techniques (k = 0.75). Non-EPI DWI is less susceptible to skull base artefacts although the mean cholesteatoma measurement difference was only 0.53 mm.

Conclusion

RS-EPI has comparable PPV with non-EPI DWI in both primary and post-operative cholesteatoma but slightly lower negative predictive value. When there is a mismatch, non-EPI DWI better predicts the presence of cholesteatoma. There is good agreement between the sequences for cholesteatoma diagnosis. The T ₁W sequence is very important in downgrading indeterminate DWI signal lesions to a negative score.

Advances in knowledge

This is, to our knowledge, the first study to compare a multishot EPI DWI technique with the established non- EPI DWI in cholesteatoma diagnosis.

Cross Sectional Imaging of the Ear and Temporal Bone

CT and MR imaging are essential cross-sectional imaging modalities for assessment of temporal bone anatomy and pathology. The choice of CT versus MR depends on the structures and the disease processes that require assessment, delineation, and characterization. A thorough knowledge of the two imaging modalities' capabilities and of temporal bone anatomy greatly facilitates imaging interpretation of pathologic conditions.

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.

Role of diffusion-weighted imaging in skull base lesions: A pictorial review

Skull base lesions can be related to wide number of pathologies including infections, benign and malignant tumors. Accurate diagnosis and differentiation between these entities is important for prompt and appropriate treatment. However, computed tomography and routine magnetic resonance imaging techniques only provide information on the extent of the lesions, with limited ability to differentiate between benign and malignant lesions. Diffusion-weighted imaging can help in many such situations by providing additional information, including help in differentiating benign from malignant lesions, so that appropriate treatment can be initiated. In this review article, we illustrate the imaging findings of the spectrum of skull base lesions, emphasizing the role of diffusion-weighted imaging in this domain.

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.

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.

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.

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.

Diagnostic accuracy of diffusion-weighted MR imaging versus delayed gadolinium enhanced T1-weighted imaging in middle ear recurrent cholesteatoma: A retrospective study of 39 patients

OBJECTIVE

MR imaging using diffusion-weighted (DW) images and delayed gadolinium-enhanced T1-weighted images is evolving into an alternative to second look surgery in detection of recurrent cholesteatomas. The aim of this study was to retrospectively compare the DW images, the post-gadolinium T1-weighted images and the combination of both methods in this indication.

PATIENTS AND METHODS

We retrospectively evaluated the MR examination of 39 patients clinically suspected for a recurrent cholesteatoma. Patients in the study underwent DW sequences, delayed gadolinium enhanced T1-weighted sequences as well as standard uninjected protocol using T1 and T2 sequences. Three blinded radiologists evaluated three data sets: a set of post-gadolinium T1-weighted images, a set of DW images and a set of the combination of both methods. The interobserver agreement was evaluated and the diagnostic accuracy of each method was described by sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The performances of the three techniques were also evaluated using ROC curves, from which the AUC were compared. Results were compared with surgical results or a two-year follow-up.

RESULTS

The overall sensitivity and specificity were respectively 63% and 71% for the post-gadolinium T1-weighted images, 88% and 75% for the DW images and 84% and 75% for the combined images. The PPV and NPV were respectively 89% and 33% for the post-gadolinium T1-weighted images, 93% and 62% for the DW images and 93% and 55% for the combined images. The sensitivity and the NPV were significantly different between the three methods (P<0.0001 and P=0.027). There was no statistically significant difference in specificity or PPV between the three methods (P=0.931 and P=0.650). The diagnostic accuracy evaluated with the AUC showed no statistically significant difference between the DW images and the combined images (P=0.433).

CONCLUSION

MR imaging reliably identifies those patients suspected for recurrent cholesteatoma who require a surgical second look by using DW MR imaging. The combination with delayed gadolinium enhanced T1-weighted sequences does not significantly increase the diagnostic accuracy of the examination.

Imaging Review of the Temporal Bone: Part II. Traumatic, Postoperative, and Noninflammatory Nonneoplastic Conditions

The first part of this review of the temporal bone discussed anatomy of the temporal bone as well as inflammatory and neoplastic processes in the temporal bone region (1). This second part will first discuss trauma to the temporal bone and posttraumatic complications. The indications for common surgical procedures performed in the temporal bone and their postoperative imaging appearance are then presented. Finally, a few noninflammatory nonneoplastic entities involving the temporal bone are reviewed. They are relatively uncommon diagnoses compared with infectious or inflammatory diseases. However, because patients present with symptoms that are either common (hearing loss) or distinctive (sensorineural hearing loss in a child), they are important for the radiologist to be aware of and recognize.

A Systematic Review of Non-Echo Planar Diffusion-Weighted Magnetic Resonance Imaging for Detection of Primary and Postoperative Cholesteatoma

Objective

To investigate the diagnostic value of non–echo planar diffusion-weighted magnetic resonance imaging (DW-MRI) for primary and recurrent/residual (postoperative) cholesteatoma in adults (≥18 years) after canal wall up surgery.

Data Sources

We conducted a systematic search in PubMed, Embase, and Cochrane up to October 22, 2014.

Review methods

All studies investigating non–echo planar DW-MRI for primary and postoperative cholesteatoma were selected and critically appraised for relevance and validity.

Results

In total, 779 unique articles were identified, of which 23 articles were included for critical appraisal. Seven articles met our criteria for relevance and validity for postoperative cholesteatoma. Four studies were additionally included for subgroup analysis of primary cases only. Ranges of sensitivity, specificity, positive predictive value, and negative predictive value yielded 43%-92%, 58%-100%, 50%-100% and 64%-100%, respectively. Results for primary subgroup analysis were 83%-100%, 50%-100%, 85%-100%, and 50%-100%, respectively. Results for subgroup analysis for only postoperative cases yielded 80%-82%, 90%-100%, 96%-100%, 64%-85%, respectively. Despite a higher prevalence of cholesteatoma in the primary cases, there was no clinical difference in added value of DW-MRI between primary and postoperative cases.

Conclusion

We found a high predictive value of non–echo planar DW-MRI for the detection of primary and postoperative cholesteatoma. Given the moderate quality of evidence, we strongly recommend both the use of non-echo planar DW-MRI scans for the follow-up after cholesteatoma surgery, and when the correct diagnosis is questioned in primary preoperative cases.

Non-echoplanar diffusion-weighted MRI in children and adolescents with cholesteatoma: reliability and pitfalls in comparison to middle ear surgery

BACKGROUND

Currently, there is only limited and contradictory evidence of the role of diffusion-weighted MRI (DW-MRI) in the management of children with cholesteatoma.

OBJECTIVE

To provide surgically controlled data that may allow to replace second-look surgery by non-echoplanar DW-MRI in children.

MATERIALS AND METHODS

Fifty-five children and adolescents with a median age of 8.6 years (2.2-17.7 years) underwent 61 preoperative half-Fourier acquisition single-shot turbo spin-echo (HASTE) DW-MRI of their petrous bone. Surgical interventions followed within 24 h (79%), within 5 months (20%) or at 18 months (1 case).

RESULTS

Surgery detected a cholesteatoma or retraction pocket in 41 of 61 cases (67%). In 49 cases (80%), the MR result was confirmed by surgical findings. Two MR findings were false-positive and 10 false-negative (including cholesteatomas <4 mm). HASTE DW-MRI alone had a sensitivity of 76% and a specificity of 90%. The positive predictive value was 94%, the negative predictive value 64%. In combination with preoperative otoscopy, sensitivity was 90% and negative predictive value 82%.

CONCLUSION

DW-MRI correctly detected the majority of lesions but could not reliably exclude small cholesteatomas and empty retraction pockets. We would therefore not generally recommend MR as a substitute for second-look surgery.

Diffusion weighted MR imaging of primary and recurrent middle ear cholesteatoma: an assessment by readers with different expertise

Introduction and Purpose. Diffusion weighted imaging (DWI) has been proven to be valuable in the diagnosis of middle ear cholesteatoma. The aims of our study were to evaluate the advantage of multi-shot turbo spin echo (MSh TSE) DWI compared to single-shot echo-planar (SSh EPI) DWI for the diagnosis of cholesteatoma. Material and Methods. Thirty-two patients with clinical suspicion of unilateral cholesteatoma underwent preoperative MRI (1.5T) with SSh EPI and MSh TSE. Images were separately analyzed by 4 readers with different expertise to confirm the presence of cholesteatoma. Sensitivity, specificity, diagnostic accuracy, and positive (PPV) and negative predictive values (NPV) were assessed for each observer and interrater agreement was assessed using kappa statistics. Diagnosis was obtained at surgery. Results. Overall MSh TSE showed higher diagnostic accuracy and lower negative predictive value (NPV) compared to conventional SSh EPI. Interreader agreement between the observers revealed the superiority of MSh TSE compared to SSh EPI. Interrater agreement among all the four observers was higher by using MSh TSE compared to SSh EPI. Conclusion. Our findings suggest that MSh TSE DWI has higher sensitivity for detection of cholesteatoma and lower probability of misdiagnosis. MSh TSE DWI is useful in guiding less experienced observers to the diagnosis.

Temporal bone imaging

Temporal bone imaging is performed for a variety of clinical conditions addressed in the outpatient and acute care setting ranging from hearing loss to trauma. Recent advances in magnetic resonance technology have enhanced the assessment of fine anatomic temporal bone detail and improved the diagnostic sensitivity for important pathology. For example, non-echo planar diffusion weighted imaging increases detection rate and diagnostic confidence of recurrent cholesteatoma. This chapter will focus on relevant temporal bone clinical entities and new MR developments that have come into clinical practice.

Role of apparent diffusion coefficients with diffusion-weighted magnetic resonance imaging in differentiating between benign and malignant bone tumors

Background

Benign and malignant bone tumors can present similar imaging features. This study aims to evaluate the significance of apparent diffusion coefficients (ADC) in differentiating between benign and malignant bone tumors.

Methods

A total of 187 patients with 198 bone masses underwent diffusion-weighted (DW) magnetic resonance (MR) imaging. The ADC values in the solid components of the bone masses were assessed. Statistical differences between the mean ADC values in the different tumor types were determined by Student’s t-test.

Results

Histological analysis showed that 84/198 (42.4%) of the bone masses were benign and 114/198 (57.6%) were malignant. There was a significant difference between the mean ADC values in the benign and malignant bone lesions (P <0.05). However, no significant difference was found in the mean ADC value between non-ossifying fibromas, osteofibrous dysplasia, and malignant bone tumors. When an ADC cutoff value ≥1.10 × 10⁻³ mm²/s was applied, malignant bone lesions were excluded with a sensitivity of 89.7%, a specificity of 84.5%, a positive predictive value of 82.6%, and a negative predictive value of 95.3%.

Conclusions

The combination of DW imaging with ADC quantification and T2-weighted signal characteristics of the solid components in lesions can facilitate differentiation between benign and malignant bone tumors.

Advances in magnetic resonance imaging of the skull base

Introduction Over the past 20 years, magnetic resonance imaging (MRI) has advanced due to new techniques involving increased magnetic field strength and developments in coils and pulse sequences. These advances allow increased opportunity to delineate the complex skull base anatomy and may guide the diagnosis and treatment of the myriad of pathologies that can affect the skull base. Objectives The objective of this article is to provide a brief background of the development of MRI and illustrate advances in skull base imaging, including techniques that allow improved conspicuity, characterization, and correlative physiologic assessment of skull base pathologies. Data Synthesis Specific radiographic illustrations of increased skull base conspicuity including the lower cranial nerves, vessels, foramina, cerebrospinal fluid (CSF) leaks, and effacement of endolymph are provided. In addition, MRIs demonstrating characterization of skull base lesions, such as recurrent cholesteatoma versus granulation tissue or abscess versus tumor, are also provided as well as correlative clinical findings in CSF flow studies in a patient pre- and post-suboccipital decompression for a Chiari I malformation. Conclusions This article illustrates MRI radiographic advances over the past 20 years, which have improved clinicians' ability to diagnose, define, and hopefully improve the treatment and outcomes of patients with underlying skull base pathologies.