Apparent diffusion coefficient values of middle ear cholesteatoma differ from abscess and cholesteatoma admixed infection

Readout-Segmented Echoplanar (RESOLVE) Diffusion-Weighted Imaging on 3T MRI in Detection of Cholesteatoma-Our Experience

Background  Several research studies have demonstrated the utility of diffusion-weighted imaging (DWI) in detecting middle ear cholesteatomas, especially with the non-echoplanar imaging (non-EPI) DWI technique. REadout Segmentation Of Long Variable Echo trains (RESOLVE), a multishot-EPI DWI, has better spatial resolution at a thinner section acquisition with reduced image distortion compared to the single-shot-EPI DWI technique. Purpose  In this study, we evaluated the diagnostic ability of RESOLVE -DWI in middle ear cholesteatomas with surgical and histopathological support. Patients and Methods  Fifty patients with clinical suspicion of primary cholesteatoma or postoperative recurrence were subjected to routine sequences and RESOLVE-DWI on magnetic resonance imaging (MRI). Thirty-eight patients had unilateral disease, while 12 patients had bilateral disease. The bilateral temporal bones of 50 patients were evaluated on MRI. The results attained by RESOLVE-DWI were correlated with intraoperative and histopathological findings. Results  RESOLVE-DWI truly detected 55 of the 58 surgically proven cholesteatomas. RESOLVE-DWI could not detect three cholesteatoma lesions due to their small size and falsely diagnosed one case each of impacted wax and non-cholesteatomatous otitis media as cholesteatoma. With a 95% confidence interval, RESOLVE-DWI showed 94.8% sensitivity, 95.2% specificity, 96% positive predictive value, 93% negative predictive value, and 95% diagnostic accuracy in cholesteatoma detection. Conclusion  RESOLVE-DWI is a sensitive and specific DWI technique for detecting middle ear cholesteatoma. However, RESOLVE-DWI has limitations in the diagnosis of small (<3 mm) cholesteatomas.

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.

Radiological Follow-up After the Bony Obliteration Tympanoplasty in Detecting Residual Cholesteatoma: Towards an Optimal Postoperative MR Imaging Protocol

INTRODUCTION AND AIM

There is no consensus in literature on the most optimal follow-up imaging protocol for non-echoplanar diffusion-weighted magnetic resonance imaging (non-EP DW MRI) after the canal wall-up bony obliteration tympanoplasty. Clearly, no residual cholesteatoma should be missed but on the other hand, unnecessary MR controls should be avoided. The aim of this study is to evaluate the postoperative results of non-EP DW MRI after canal wall-up bony obliteration tympanoplasty surgery at our Institute and to propose an optimal postoperative MR imaging scheme based on our data.

MATERIAL AND METHODS

Retrospective cohort study; all 271 patients who underwent the bony obliteration tympanoplasty between January 2010 and January 2016 with follow-up at our Institute were included. A postoperative MR imaging was systematically performed at 1 year after surgery and repeated at either 5 or both 3 and 5 years after surgery, based on the preferences of the surgeon. Variables of interest were retrieved from electronic patient records.

RESULTS

The median follow-up time was 60 months (inter-quartile range 56-62 mo). Two hundred seventy-one patients (100%) received a 1-year MRI, 107 (39%) a 3-year MRI, and 216 (79.7%%) a 5-year MRI. Residual cholesteatoma was found in nine cases (3.3%), corresponding with an estimated residual rate at 5 years follow-up of 3.7% when using Kaplan-Meier analysis. Of these nine cases, six cases of residual cholesteatoma (66.7%) were detected at the 1-year MRI (12-14 mo postsurgery), two cases (22.2%) at the 3-year MRI (35-39 mo postsurgery), and one case (11.1%) at the 5-year MRI (51 mo postsurgery, in this patient no 3-year MRI was performed). An uncertain MRI result was found in 15 cases, presenting as relatively hyperintense lesions. However, subsequent follow-up scans did not show persistent evidence for residual disease in 14 of these 15 cases.

CONCLUSIONS

A postoperative MRI scan after 1 and 5 years is essential to detect early and late residual cholesteatoma. In our cohort, 22.2% of residual cases were detected at the 3-year MRI. However, this percentage could potentially have been higher when all patients would have received a 3-year MRI. Therefore, in order to detect residual disease as soon as possible, we propose to perform an MRI scan at 1, 3, and 5 years after the bony obliteration tympanoplasty. In cases with an unclear MR result, we suggest a repeat MRI after 12 months.

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.

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.

Performance of TGSE BLADE DWI compared with RESOLVE DWI in the diagnosis of cholesteatoma

Background

Based on its high resolution in soft tissue, MRI, especially diffusion-weighted imaging (DWI), is increasingly important in the evaluation of cholesteatoma. The purpose of this study was to evaluate the role of the 2D turbo gradient- and spin-echo (TGSE) diffusion-weighted (DW) pulse sequence with the BLADE trajectory technique in the diagnosis of cholesteatoma at 3 T and to qualitatively and quantitatively compare image quality between the TGSE BLADE and RESOLVE methods.

Method

A total of 42 patients (23 males, 19 females; age range, 7–65 years; mean, 40.1 years) with surgically confirmed cholesteatoma in the middle ear were enrolled in this study. All patients underwent DWI (both a prototype TGSE BLADE DWI sequence and the RESOLVE DWI sequence) using a 3-T scanner with a 64-channel brain coil.

Qualitative imaging parameters (imaging sharpness, geometric distortion, ghosting artifacts, and overall imaging quality) and quantitative imaging parameters (apparent diffusion coefficient [ADC], signal-to-noise ratio [SNR], contrast, and contrast-to-noise ratio [CNR]) were assessed for the two diffusion acquisition techniques by two independent radiologists.

Result

A comparison of qualitative scores indicated that TGSE BLADE DWI produced less geometric distortion, fewer ghosting artifacts (P < 0.001) and higher image quality (P < 0.001) than were observed for RESOLVE DWI. A comparison of the evaluated quantitative image parameters between TGSE and RESOLVE showed that TGSE BLADE DWI produced a significantly lower SNR (P < 0.001) and higher parameter values (both contrast and CNR (P < 0.001)) than were found for RESOLVE DWI.

The ADC (P < 0.001) was significantly lower for TGSE BLADE DWI (0.763 × 10^− 3 mm²/s) than RESOLVE DWI (0.928 × 10^− 3 mm²/s).

Conclusion

Compared with RESOLVE DWI, TGSE BLADE DWI significantly improved the image quality of cholesteatoma by reducing magnetic sensitive artifacts, distortion, and blurring. TGSE BLADE DWI is more valuable than RESOLVE DWI for the diagnosis of small-sized (2 mm) cholesteatoma lesions. However, TGSE BLADE DWI also has some disadvantages: the whole image intensity is slightly low, so that the anatomical details of the air-bone interface are not shown well, and this shortcoming should be improved in the future.

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.

Improved Assessment of Middle Ear Recurrent Cholesteatomas Using a Fusion of Conventional CT and Non-EPI-DWI MRI

BACKGROUND AND PURPOSE

Recurrent middle ear cholesteatomas are commonly preoperatively assessed using MR imaging (non-EPI-DWI) and CT. Both modalities are used with the aim of distinguishing scar tissue from cholesteatoma and determining the extent of bone erosions. Inflammation and scar tissue associated with the lesions might hamper a proper delineation of the corresponding extensions on CT images. Using surgical findings as the criterion standard, we assessed the recurrent middle ear cholesteatoma extent using either uncoregistered or fused CT-MR imaging datasets and determined the corresponding accuracy and repeatability.

MATERIALS AND METHODS

Twenty consecutive patients with suspected recurrent middle ear cholesteatoma and preoperative CT-MR imaging datasets were prospectively included. A double-blind assessment and coregistration of the recurrent middle ear cholesteatoma extent and manual delineation of 18 presumed recurrent middle ear cholesteatomas were performed by 2 radiologists and compared with the criterion standard. "Reliability score" was defined to qualify radiologists' confidence. For each volume, segmentation repeatability was assessed on the basis of intraclass correlation coefficient and overlap indices.

RESULTS

For the whole set of patients, recurrent middle ear cholesteatoma was further supported by surgical results. Two lesions were excluded from the analysis, given that MR imaging did not show a restricted diffusion. Lesions were accurately localized using the fused datasets, whereas significantly fewer lesions (85%) were correctly localized using uncoregistered images. Reliability scores were larger for fused datasets. Segmentation repeatability showed an almost perfect intraclass correlation coefficient regarding volumes, while overlaps were significantly lower in uncoregistered (52%) compared with fused (60%, P < .001) datasets.

CONCLUSIONS

The use of coregistered CT-MR images significantly improved the assessment of recurrent middle ear cholesteatoma with a greater accuracy and better reliability and repeatability.

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.

Parotid gland cholesteatoma in a 23-year-old male: Case report

Cholesteatoma is a pathological tissue that may extend into all parts of temporal bone and rarely, as this study highlights, beyond its structures. Nevertheless, the spread outside the mastoid tip into the soft tissues of the neck or parotid space is very rare. The case of 23-year-old male with right parotid mass is presented. The patient had history (2006, 2009, and 2012) of three tympanoplastics for recurrent right ear cholesteatoma. The parotid tumor was revealed incidentally in magnetic resonance imaging in January 2016, but the imaging was inconclusive. After 6 months, the patient developed right-sided facial nerve palsy. The second look of the right ear was performed with simultaneous parotid surgery. The ear was healed and free of cholesteatoma, but the parotid mass resembled the cholesteatoma confirmed later on by histological examination. The tumor extended from stylomastoid foramen. This case was unusual as the disease had extended beyond the ear with the bony parts of the mastoid being preserved. To our knowledge, this is the first case report to describe a parotid gland cholesteatoma not being an extension of a cholesteatoma present in the tympanic cavity and entering the parotid gland via stylomastoid foramen.

The accuracy and sensitivity of diffusion-weighted magnetic resonance imaging with Apparent Diffusion Coefficients in diagnosis of recurrent cholesteatoma

OBJECTIVE

To evaluate the accuracy and sensitivity of diffusion-weighted magnetic resonance imaging with ADC value combined with MDCT in evaluating recurrent cholesteatoma.

PATIENTS

Thirty patients (20 females and 10 males), their age ranged from 10 to 40years, had undergone a tympanomastoid surgery for a cholesteatoma of the middle ear underwent MDCT and MR DWI examination before second- or third-look surgery from May 2015 to October 2016.

RESULTS

CT showed partial opacification of the tympanomastoid cavity in 10 ears and complete opacification in 21 ears. CT detects 10 cases out of 20 cases of recurrent cholesteatoma with sensitivity 47.6%, specificity 100%, and NPP 47.6%. DWI depicted 21 out of 20 cases proved cholesteatoma patients (sensitivity 100%, specificity 90%, PPV 95.2% and P value is 0.001). All MRI of patients without cholesteatoma were correctly interpreted as showing negative findings for cholesteatoma (specificity = 100%). The ADC of cholesteatoma group (21 ears) were ranged from 553 to 759 × 10-3 mm2/s and the ADCs of non cholesteatoma group (10 ears) was ranged from 1495.8 to 1766.8 × 10-3 mm2/s. Cut off value of cholesteatoma is ≤759 × 10-3 mm2/s.

CONCLUSION

MR DWI with ADC combined with MDCT has high sensitivity, specificity, accuracy in detecting recurrent cholesteatoma.

Diffusion-Weighted Imaging in Meningioma: Prediction of Tumor Grade and Association with Histopathological Parameters

OBJECTIVES

To analyze diffusion-weighted imaging (DWI) findings of meningiomas and to compare them with tumor grade, cell count, and proliferation index and to test a possibility of use of apparent diffusion coefficient (ADC) to differentiate benign from atypical/malignant tumors.

METHODS

Forty-nine meningiomas were analyzed. DWI was done using a multislice single-shot echo-planar imaging sequence. A polygonal region of interest was drawn on ADC maps around the margin of the lesion. In all lesions, minimal ADC values (ADCmin) and mean ADC values (ADCmean) were estimated. Normalized ADC (NADC) was calculated in every case as a ratio ADCmean meningioma/ADCmean white matter. All meningiomas were surgically resected and analyzed histopathologically. The tumor proliferation index was estimated on Ki-67 antigen-stained specimens. Cell density was calculated. Collected data were evaluated by means of descriptive statistics. Analyses of ADC/NADC values were performed by means of two-sided t tests.

RESULTS

The mean ADCmean value was higher in grade I meningiomas in comparison to grade II/III tumors (0.96 vs 0.80 × 10(-3) mm(2)s(-1), P = .006). Grade II/III meningiomas showed lower NADC values in comparison to grade I tumors (1.05 vs 1.26, P = .015). There was no significant difference in ADCmin values between grade I and II/III tumors (0.69 vs 0.63 × 10(-3) mm(2)s(-1), P = .539). The estimated cell count varied from 486 to 2091 (mean value, 1158.20 ± 333.74; median value, 1108). There were no significant differences in cell count between grade I and grade II/III tumors (1163.93 vs 1123.86 cells, P = .77). The mean level of the proliferation index was 4.78 ± 5.08%, the range was 1% to 18%, and the median value was 2%. The proliferation index was statistically significant higher in grade II/III meningiomas in comparison to grade I tumors (15.43% vs 3.00%, P = .001). Ki-67 was negatively associated with ADCmean (r = -0.61, P < .001) and NADC (r = -0.60, P < .001). No significant correlations between cell count and ADCmean (r = -0.20, P = .164) or NADC (r = -0.25, P = .079) were found. ADCmin correlated statistically significant with cell count (r = -0.44, P = .002) but not with Ki-67 (r = -0.22, P = .129). Furthermore, the association between ADCmin and cell count was stronger in grade II/III tumors (r = -0.79, P = .036) versus grade I meningiomas (r = -0.41, P = .008). An ADCmean value of less than 0.85 × 10(-3) mm(2)s(-1) was determined as the threshold in differentiating between grade I and grade II/III meningiomas (sensitivity 72.9%, specificity 73.1%, accuracy 73.0%). The positive and negative predictive values were 33.3% and 96.8%, respectively. The same threshold ADCmean value was used in differentiating between tumors with Ki-67 level ≥5% and meningiomas with low proliferation index (Ki-67 <5%). This threshold yielded a sensitivity of 70.6%, a specificity of 81.2%, and an accuracy of 77.6%. The positive and negative predictive values were 66.6% and 83.9%, respectively.

CONCLUSIONS

Grade II/III tumors had lower ADCmean values than grade I meningiomas. ADCmean correlated negatively with tumor proliferation index and ADCmin with tumor cell count. These associations were different in several meningiomas. ADCmean can be used for distinguishing between benign and atypical/malignant tumors.

Evaluation of cholesteatoma: our experience with DW Propeller imaging

BACKGROUND

Cholesteatoma management includes early detection and surgical exploration. Due to its tendency to recur, it can be potentially locally aggressive. Magnetic resonance imaging (MRI), and in particular diffusion weighted imaging (DWI), plays an important role in management of these lesions.

PURPOSE

To assess the accuracy of Propeller (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) DW sequence in detecting middle ear and mastoid cholesteatomas in non-operated ears by surgical correlation.

MATERIAL AND METHODS

A retrospective review of 15 patients was done who underwent Propeller DWI with either clinically confirmed or suspected cholesteatomas. Surgical correlation was done in all cases.

RESULTS

All patients had hyperintense foci on Propeller DWI. Surgical correlation performed revealed that 13 patients had cholesteatomas while two patients had mastoid abscesses. The location, extent, and size of cholesteatomas on Propeller DWI matched with the operative findings. Of the 13 patients with cholesteatomas, three patients had multiple foci of hyperintensity on Propeller DWI, which corroborated with the surgical finding of multiple cholesteatomas. The average apparent diffusion coefficient value of cholesteatoma was 0.868 × 10(-3) mm(2)/s, found to be higher than that of abscess, which was 0.425 × 10(-3) mm(2)/s.

CONCLUSION

Propeller DWI was accurate in assessing the location, extent, and size of cholesteatomas as corroborated with surgical findings. Propeller DWI is useful in detecting number of cholesteatoma foci, a vital finding as it may impact the choice of surgery.

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 imaging of nasopharyngeal adenoid hypertrophy

BACKGROUND

Diffusion-weighted imaging (DWI) could be helpful for the differentiation of malignant and benign entities. Nasopharyngeal adenoid hypertrophy (NAH) is a typical benign lesion. DWI appearances of this lesion have not been reported previously.

PURPOSE

To identify and to analyse DWI findings of NAH.

MATERIAL AND METHODS

We analyzed 688 MR investigations of the head performed at our institution. Magnetic resonance imaging (MRI) was obtained at a 1.5 T MRI device. Beside normal standard sequences DWI was obtained using a multislice single-shot echo-planar sequence. DWI was performed with b values of 0, 500, and 1000 s/mm(2).

RESULTS

The mean whole lesion ADC value was 0.83 ± 0.12 × 10(-3) mm(2) s(-1) (median, 0.82 × 10(-3) mm(2) s(-1); range, 0.58-1.45 × 10(-3) mm(2) s(-1)). The mean ADC value of solid areas of NAH was 0.59 ± 0.11 × 10(-3) mm(2) s(-1) (range, 0.36-0.84 × 10(-3) mm(2) s(-1)).

CONCLUSION

Although NAH is a benign lesion, it shows low ADC values both in childhood and in adults. This finding should be kept in mind to avoid possible misinterpretations as a malignant lesion.

Facial extention of ear pathology: infected cholesteatoma causing a parotid abscess

A man in his early 30s presented with right-sided preauricular swelling and facial oedema. He had a history of acid injury to his right ear as a child resulting in pinna deformity and subsequent blind sac closure of the external auditory canal. Imaging showed abnormal ear anatomy and abnormal density of the right parotid gland. Antibiotic therapy prevented progression but did not resolve the symptoms. Therefore, the infected area was surgically drained. This showed an underlying cholesteatoma, a benign but locally destructive condition where keratinising squamous epithelium grows in the middle ear and mastoid. The infected region was drained and the cholesteatoma was excised. This led to full resolution of the infection. The patient is awaiting a follow-up diffusion-weighted MRI. This case was unusual as the disease had extended beyond the ear and we therefore wish to alert clinicians to cholesteatoma as a possible cause of facial swelling.

MR imaging features of acute mastoiditis and their clinical relevance

BACKGROUND AND PURPOSE

MR imaging is often used for detecting intracranial complications of acute mastoiditis, whereas the intratemporal appearance of mastoiditis has been overlooked. The aim of this study was to assess the imaging features caused by acute mastoiditis in MR imaging and their clinical relevance.

MATERIALS AND METHODS

Medical records and MR imaging findings of 31 patients with acute mastoiditis (21 adults, 10 children) were analyzed retrospectively. The degree of opacification in the temporal bone, signal and enhancement characteristics, bone destruction, and the presence of complications were correlated with clinical history and outcome data, with pediatric and adult patients compared.

RESULTS

Most patients had ≥50% of the tympanic cavity and 100% of the mastoid antrum and air cells opacified. Compared with CSF, they also showed intramastoid signal changes in T1 spin-echo, T2 TSE, CISS, and DWI sequences; and intramastoid, outer periosteal, and perimastoid dural enhancement. The most common complications in MR imaging were intratemporal abscess (23%), subperiosteal abscess (19%), and labyrinth involvement (16%). Children had a significantly higher prevalence of total opacification of the tympanic cavity (80% versus 19%) and mastoid air cells (90% versus 21%), intense intramastoid enhancement (90% versus 33%), outer cortical bone destruction (70% versus 10%), subperiosteal abscess (50% versus 5%), and perimastoid meningeal enhancement (80% versus 33%).

CONCLUSIONS

Acute mastoiditis causes several intra- and extratemporal changes on MR imaging. Total opacification of the tympanic cavity and the mastoid, intense intramastoid enhancement, perimastoid dural enhancement, bone erosion, and extracranial complications are more frequent in children.

Apparent diffusion coefficients for detection of postoperative middle ear cholesteatoma on non-echo-planar diffusion-weighted images

PURPOSE

To determine whether there is a difference between the apparent diffusion coefficients (ADCs) of postoperative middle ear cleft cholesteatoma and noncholesteatomatous tissue on half-Fourier acquisition single-shot turbo spin-echo diffusion-weighted (DW) images and to determine, with interobserver agreement, a predictive accuracy for diagnosis of postoperative middle ear cleft cholesteatoma.

MATERIALS AND METHODS

Patients who underwent DW magnetic resonance (MR) examination before repeat explorative surgery for postoperative cholesteatoma were included in this study. There were 72 patient episodes and 56 patients. DW MR images were acquired with b values 0 and 1000 sec/mm(2) and 2-mm section thicknesses. Two observers assessed images qualitatively for presence of cholesteatoma and recorded ADCs. Surgery with histologic confirmation established final diagnosis of abnormal middle ear cleft soft tissue. ADCs between cholesteatoma and noncholesteatomatous tissue were compared with Mann-Whitney test. Effects of ADCs and confidence intervals to indicate presence of cholesteatoma were examined by using receiver operating characteristic (ROC) curve analysis, logistic regression analysis, and interobserver agreement.

RESULTS

Forty-six patients had cholesteatoma and 25 patients did not; sensitivity and specificity were 0.91 and 0.88, respectively, for the qualitative diagnosis of postoperative cholesteatoma by using a five-point confidence scale. ADC of cholesteatoma (median, 707 × 10(-6) mm(2)/sec; interquartile range, 539-858 × 10(-6) mm(2)/sec; P < .001) was significantly lower than that of noncholesteatomatous tissue (median, 1849 × 10(-6) mm(2)/sec; interquartile range, 1574-1982 × 10(-6) mm(2)/sec; P < .001). There was good accuracy (area under the ROC curve, 0.97) and interobserver agreement for detecting postoperative cholesteatoma with ADC threshold less than 1300 × 10(-6) mm(2)/sec.

CONCLUSION

The ADC value of postoperative middle ear cleft cholesteatoma is significantly lower than that of noncholesteatomatous tissue and has good accuracy for detecting cholesteatoma.

High-resolution three-dimensional diffusion-weighted imaging of middle ear cholesteatoma at 3.0 T MRI: usefulness of 3D turbo field-echo with diffusion-sensitized driven-equilibrium preparation (TFE-DSDE) compared to single-shot echo-planar imaging

OBJECTIVE

To prospectively evaluate the usefulness of a newly developed high-resolution three-dimensional diffusion-weighted imaging method, turbo field-echo with diffusion-sensitized driven-equilibrium (TFE-DSDE) in diagnosing middle-ear cholesteatoma by comparing it to conventional single-shot echo-planar diffusion-weighted imaging (SS-EP DWI).

MATERIALS AND METHODS

Institutional review board approval and informed consent from all participants were obtained. We studied 30 patients with preoperatively suspected acquired cholesteatoma. Each patient underwent an MR examination including both SS-EP DWI and DSDE-TFE using a 3.0 T MR scanner. Images of the 30 patients (60 temporal bones including 30 with and 30 without cholesteatoma) were reviewed by two independent neuroradiologists. The confidence level for the presence of cholesteatoma was graded on a scale of 0-2 (0=definite absence, 1=equivocal, 2=definite presence). Interobserver agreement as well as sensitivity, specificity, and accuracy for detection were assessed for the two reviewers.

RESULTS

Excellent interobserver agreement was shown for TFE-DSDE (κ=0.821) whereas fair agreement was obtained for SS-EP DWI (κ=0.416). TFE-DSDE was associated with significantly higher sensitivity (83.3%) and accuracy (90.0%) compared to SS-EP DWI (sensitivity=35.0%, accuracy=66.7%; p<0.05). No significant difference was found in specificity (96.7% for TFE-DSDE, 98.3% for SS-EP DWI) CONCLUSION: With increased spatial resolution and reduced susceptibility artifacts, TFE-DSDE improves the accuracy in diagnosing acquired middle ear cholesteatomas compared to SS-EP DWI.

MRI for the diagnosis of recurrent middle ear cholesteatoma in children--can we optimize the technique? Preliminary study

BACKGROUND

Recurrent cholesteatoma after surgical excision occurs frequently in children. Until recently, a surgical second look was mandatory and considered as standard reference. MRI including a delayed T1 sequence after gadolinium injection and diffusion-weighted imaging (DWI) has proved its efficiency but has been evaluated mainly in adults.

OBJECTIVE

Our purpose was to evaluate the accuracy of DWI to diagnose recurrence of cholesteatoma in children.

MATERIALS AND METHODS

We evaluated prospectively with MRI 20 ears in 18 children who had had surgery for cholesteatoma. We compared DWI and delayed T1-weighted images following gadolinium administration with intraoperative or follow-up findings. We calculated the sensitivity and specificity of each sequence for the diagnosis of recurrent cholesteatoma.

RESULTS

Sensitivity to diagnose recurrent cholesteatoma was 87% for both DWI and delayed post-gadolinium sequences, specificity was 71% and 83%, respectively. Adding both sequences, the sensitivity was 87%, the specificity 100%. There was one false negative probably due to small size recurrence.

CONCLUSION

In our series, DWI was reliable to diagnose recurrent cholesteatoma in children and allows avoiding surgery when negative. However, because small recurrences less than 5 mm may be missed, follow-up must be prolonged (5 years).

Contemporary non-echo-planar diffusion-weighted imaging of middle ear cholesteatomas

Middle ear cholesteatoma is a common inflammatory disease that requires surgery due to potentially serious intracranial complications. Diagnosis of cholesteatoma is mainly clinical, with computed tomography (CT) used to evaluate disease extension before surgery. Certain patterns of bone erosion are specific, but CT attenuation does not allow differentiation from other inflammatory middle ear diseases. With its high tissue discrimination and contrast resolution, magnetic resonance imaging is valuable in diagnosis of cholesteatomas. Absent enhancement at delayed postcontrast imaging has been used for diagnosis. Diffusion-weighted imaging (DWI) is highly specific due to the high keratin content of cholesteatomas. New non-echo-planar DWI sequences, such as periodically rotated overlapping parallel lines with enhanced reconstruction, are superior to conventional echo-planar DWI, since they minimize susceptibility artifacts at the skull base and increase sensitivity for detection of lesions as small as 2 mm. This technique is indicated when clinical diagnosis is difficult and high tissue specificity is necessary, as in congenital, temporal bone, or atypical acquired middle ear cholesteatomas and residual or recurrent disease after surgery. Non-echo-planar DWI has been proposed for screening of postsurgical (residual or recurrent) cholesteatomas, thus obviating many second-look revision surgeries, especially after more conservative canal wall up surgery.

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

BACKGROUND AND PURPOSE

Non-EPI DWI is a promising alternative to second-look surgery for the detection of residual and/or recurrent cholesteatoma. We evaluated the diagnostic accuracy, expressed as a positive predictive value, of MR imaging for the detection of residual and/or recurrent cholesteatoma in our hospital.

MATERIALS AND METHODS

Fifty-six MR imaging studies were performed from 2005 to 2010 in patients having previously undergone surgery for cholesteatoma. Pre- and postgadolinium T1-weighted, T2-weighted, and non-EPI DWI sequences were performed and correlated with clinical and intraoperative findings. Twenty-seven patients underwent second-look surgery; 7 were under close clinical follow-up. Twenty-two patients without evidence of cholesteatoma were under regular follow-up (range, 14-44 months).

RESULTS

Non-EPI DWI sequences showed increased DW signal intensity in 36 patients. Of those, 27 had second-look surgery, confirming cholesteatoma in 25 patients; in 1 patient, an empyema was diagnosed, and in the other patient, no cholesteatoma was found at surgery. In 2 patients who had not undergone surgery, increased DW signal intensity was accompanied by hyperintense signal intensity on T1-weighted images, consistent with transplanted fat in the postoperative cavity. The positive predictive value for detection of cholesteatoma was 93% (25/27).

CONCLUSIONS

Residual and/or recurrent cholesteatomas after primary cholesteatoma surgery can be accurately detected by increased DW signal intensity on non-EPI DWI. However, DWI without conventional sequences increased the risk of misdiagnosis in our patient setting because transplanted fat within the postoperative cavity may show increased DW signal intensity.

Predictive validity of MRI in detecting and following cholesteatoma

High recurrence rate of the middle ear cholesteatoma requires regular postoperative follow-up. This study evaluated data from the patients investigated with DW MRI to ascertain (1) the strength of the technique in detecting primary, and residual recurrent cholesteatoma, and (2) its accuracy in differentiating cholesteatoma from postoperative tissue changes. The diagnostic accuracy of two different DW imaging (EPI and non-EPI) techniques was evaluated. The data have been collected prospectively from 33 consecutive patients with either primary cholesteatoma, or with suspicious symptoms for potential cholesteatoma recurrence. The findings from non-EPI (HASTE) DW MR and EPI DW MR images were blindly compared with those obtained during a primary or secondary surgery. Preoperative non-EPI (HASTE) DWI pointed to a cholesteatoma in 25 out of 33 patients. In this subgroup, cholesteatoma were confirmed also by the surgery. In five cases, the non-EPI (HASTE) DWI did not show a cholesteatoma in the temporal bone, which agreed with the surgical findings. Three misclassifications were made by non-EPI (HASTE) DWI, all in the subgroup of patients indicated for primary surgery. The resulting pooled sensitivity of non-EPI (HASTE) DW imaging for diagnosing cholesteatoma in our study amounted to 96.15% (95% confidence interval (CI) 80.36-99.9), specificity was 71.43% (95% CI 29.04-96.33). Positive predictive value was 92.59% (95% CI 75.71-99.09) and negative predictive value 83.33% (95% CI 35.88-99.58). In conclusion, we recommend the non-EPI (HASTE) DW MRI as a valid method for diagnosing cholesteatoma and follow-up after cholesteatoma surgery.

Detection of middle ear cholesteatoma by diffusion-weighted MR imaging: multishot echo-planar imaging compared with single-shot echo-planar imaging

BACKGROUND AND PURPOSE

Previous reports have shown that DWI is useful in detecting cholesteatoma. SS-EPI is the most widely used DWI technique. However, SS-EPI may have susceptibility artifacts due to field inhomogeneity in the imaging of the temporal bone region. Our purpose was to prospectively evaluate the advantage of MS-EPI for the diagnosis of middle ear cholesteatoma by comparing it with SS-EPI.

MATERIALS AND METHODS

We studied 29 patients with preoperatively suspected acquired cholesteatoma. Each patient underwent an MR imaging examination including both SS-EPI and MS-EPI by using a 1.5T MR imaging scanner. Images of the 29 patients (58 temporal bones including 30 with and 28 without cholesteatoma) were reviewed by 2 independent neuroradiologists. The confidence level for the presence of cholesteatoma was graded on a scale of 0-2 (0 = none, 1 = equivocal, 2 = definite). Interobserver agreement as well as sensitivity, specificity, and accuracy were assessed for the 2 readers.

RESULTS

Excellent interobserver agreement was shown for both MS-EPI (κ = 0.856) and SS-EPI (κ = 0.820). MS-EPI was associated with higher sensitivity (76.7%) and accuracy (87.9%) than SS-EPI (sensitivity = 50.0%, accuracy = 74.1%) (P < .05), while both methods showed 100% specificity.

CONCLUSIONS

Compared with SS-EPI, MS-EPI improves the accuracy of the diagnosis of acquired middle ear cholesteatomas.

Diffusion-weighted MRI for evaluating perianal fistula activity: feasibility study

PURPOSE

To assess the feasibility of using diffusion-weighted magnetic resonance (MR) imaging (DWI) for evaluating perianal fistula activity.

MATERIALS AND METHODS

This study retrospectively assessed 24 patients with clinically suspected perianal fistula who underwent a total of 28 MR examinations after conservative treatment with antibiotics. DWI was performed at 1.5 T, using b-values of 0 and 1000 s/mm(2). Apparent diffusion coefficient (ADC) maps were created and ADCs of the lesions were measured. Lesions were classified into two groups based on the need for surgery and surgical findings: positive inflammation activity (PIA) and negative inflammation activity (NIA). ADCs of both groups were compared using an unpaired t-test, and Receiver Operating Characteristic (ROC) analysis was performed.

RESULTS

The ADC (in 10(-3) mm(2)/s) of the PIA group (0.908±0.171) was significantly lower (P=0.0019) than that of the NIA group (1.124±0.244). The area under the ROC curve was 0.749. An optimal cut-off ADC of 1.109 yielded a sensitivity of 95.7%, a specificity of 50%, a positive predictive value of 71%, and a negative predictive value of 90%.

CONCLUSION

DWI is a feasible method for evaluating perianal fistula activity. The diagnostic performance of this technique should be established in future, larger prospective studies.

Non echo planar, diffusion-weighted magnetic resonance imaging (periodically rotated overlapping parallel lines with enhanced reconstruction sequence) compared with echo planar imaging for the detection of middle-ear cholesteatoma

Objectives:

We evaluated use of the periodically rotated overlapping parallel lines with enhanced reconstruction diffusion-weighted imaging sequence, compared with conventional echo planar magnetic resonance imaging, in the detection of middle-ear cholesteatoma.

Material and methods:

Sixteen patients awaiting second-stage combined approach tympanoplasty and three patients awaiting first-stage combined approach tympanoplasty underwent magnetic resonance imaging with both (1) the periodically rotated overlapping parallel lines with enhanced reconstruction sequence (i.e. non echo planar imaging) and (2) the array spatial sensitivity encoding technique sequence (i.e. echo planar imaging). Two neuroradiologists independently evaluated the images produced by both sequences. Radiology findings were correlated with surgical findings.

Results and analysis:

Seven cholesteatomas were found at surgery. Neither of the assessed imaging sequences were able to detect cholesteatoma of less than 4 mm. Rates for sensitivity, specificity, and positive and negative predictive values are presented.

Conclusion:

Decisions on whether or not to operate for cholesteatoma cannot be made based on the two imaging sequences assessed, as evaluated in this study. Other contributing factors are discussed, such as the radiological learning curve and technical limitations of the magnetic resonance imaging equipment.