Computed tomographic features of the proximal petrous facial nerve canal in recurrent Bell's palsy.

OBJECTIVES: The primary objective was to determine whether the narrowest dimensions of the labyrinthine facial nerve (LFN) canal on the symptomatic side in patients with unilateral recurrent Bell's palsy (BP) differ from those on the contralateral side or in asymptomatic, age- and gender-matched controls on computed tomography (CT). The secondary objectives were to assess the extent of bony covering at the geniculate ganglion and to record inter-observer reliability of the CT measurements. METHODS: The dimensions of the LFN canal at its narrowest point perpendicular to the long axis and the extent of bony covering at the geniculate ganglion were assessed by two radiologists. Statistical analysis was performed using the Wilcoxon signed-rank and Mann-Whitney U tests (LFN canal dimensions) and the Chi-squared test (bony covering at the geniculate ganglion). Inter-observer reliability was evaluated using Intra-Class Correlation (ICC) and Cohen's kappa. RESULTS: The study included 21 patients with unilateral recurrent BP and 21 asymptomatic controls. There was no significant difference in the narrowest dimensions of the ipsilateral LFN canal when compared to the contralateral side or controls (P = .43-.94). Similarly, there was no significant difference in the extent of bony covering at the geniculate ganglion when compared to either group (P = .19-.8). Good inter-observer reliability was observed for LFN measurements (ICC = 0.75-0.88) but not for the bony covering at the geniculate ganglion (Cohen's kappa = 0.53). CONCLUSION: The narrowest dimensions of the LFN canal and the extent of bony covering at the geniculate ganglion do not differ in unilateral recurrent BP, casting doubt over their etiological significance. LEVEL OF EVIDENCE: Level IV.

Morphological comparison of internal auditory canal diverticula in the presence and absence of otospongiosis on computed tomography and their impact on patterns of hearing loss.

PURPOSE: The association of internal auditory canal (IAC) fundal diverticula with otospongiosis (OS) and their clinical significance remain unclear. We explored whether isolated IAC diverticula were morphologically different from those with additional CT features of OS, and whether IAC diverticula morphology influenced patterns of hearing loss. METHODS: Consecutive temporal bone CT studies with (n = 978) and without (n = 306) features of OS were retrospectively assessed. Two independent observers evaluated the presence of IAC diverticula morphological features (depth, neck:depth ratio, definition of contour and angulation of shape), and these were correlated with the presence of fenestral and pericochlear OS. Audiometric profiles were analysed for the isolated IAC diverticula and those with fenestral OS alone. Continuous data was compared using Wilcoxon rank sum tests and categorical data with chi-squared and Fisher's exact tests. RESULTS: Ninety-five isolated IAC diverticula were demonstrated in 54/978 patients (5.5%) without CT evidence of OS (31M, 23F, mean age 46), and 119 IAC diverticula were demonstrated in 71/306 patients (23%) with CT evidence of OS (23M, 48F, mean age 55). Reduced neck:depth ratio, ill definition and angulation were all significantly associated with the presence of pericochlear OS (p < 0.001), whilst only ill definition was associated with the presence of fenestral OS alone (p < 0.05). No morphological feature was associated with conductive hearing loss in isolated diverticula or with sensorineural hearing loss in diverticula with fenestral OS alone. CONCLUSION: IAC diverticula associated with pericochlear OS demonstrate different morphological features from isolated IAC diverticula. There are no clear audiometric implications of these morphological features.

Growth and Late Detection of Post-Operative Cholesteatoma on Long Term Follow-Up With Diffusion Weighted Magnetic Resonance Imaging (DWI MRI): A Retrospective Analysis From a Single UK Centre.

OBJECTIVE: To evaluate the growth rate and late detection of residual cholesteatoma on long-term follow-up with diffusion weighted magnetic resonance imaging (DWI MRI) in clinically stable ears following definitive surgery, in order to define surveillance imaging protocols. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Patients who underwent DWI MRI at our institution between February 2007 and May 2013 for postoperative cholesteatoma follow-up. INTERVENTION: Non-echo planar imaging (non-EPI) Half-Fourier Acquisition Single-shot Turbo spin Echo (HASTE) DWI MRI. MAIN OUTCOME MEASURES: Intervals between the definitive surgery and the first and subsequent DWI MRI, the maximum coronal dimension of the lesion on DWI and length of follow-up. RESULTS: The study evaluated 152 postoperative DWI studies performed for 88 patients. In 12 cases, DWI was initially negative but became positive on repeat imaging after a mean interval of 3.8 years from the initial cholesteatoma surgery (median 3.7 years, range 1.6-7.9). Of these, 3/12 had more than one negative/indeterminate DWI before disease was eventually detected on imaging; in this subgroup, the mean interval between surgery and positive DWI was 3.2 years (median 2.6 years, range 2.3-4.2). 39 DWI positive foci with serial imaging demonstrated a mean growth rate of 4 mm/year (median 2 mm, range 0-18). CONCLUSIONS: After negative initial DWI, it is proposed that interval imaging should be considered for a minimum of 5 years in stable ears following definitive cholesteatoma surgery. In view of the marked variability in growth rate, an additional interval scan between 2 and 3 years postoperatively is indicated.

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.

Diagnostic efficacy and therapeutic impact of computed tomography in the evaluation of clinically suspected otosclerosis.

OBJECTIVE: To assess the diagnostic efficacy and therapeutic impact of CT in evaluating patients with clinically suspected otosclerosis. METHODS: CT scans performed over a 5-year period for clinically suspected otosclerosis were retrospectively reviewed. CT diagnoses were correlated with subsequent surgical management. For otosclerosis positive cases, clinically significant extensions of otosclerosis were correlated with audiometry and the diagnosis was correlated with surgical findings. RESULTS: Of 259 CT studies, 46 % of patients were positive, 49 % negative and 5 % equivocal for otosclerosis. A relevant alternative CT diagnosis was evident in 33 % of the negative studies. One targeted surgery was performed for every four CT studies. CT outcome influenced the decision to perform stapedectomy in 41 % CT-positive versus 4 % CT-negative patients. CT-positive ears for otosclerosis could not be predicted from baseline clinical or audiometric criteria. Those with endosteal extension demonstrated lower bone conduction thresholds presurgically. The positive predictive value of CT diagnosis of otosclerosis was 100 %. CONCLUSIONS: CT demonstrated a high rate of clinically relevant diagnoses in both CT-positive and -negative for otosclerosis patients, and this frequently influenced surgical management. CT also added value by demonstrating relevant extensions of the otosclerotic foci, some of which were predictive of audiometric parameters. KEY POINTS: • CT demonstrates a high rate of alternative diagnoses in suspected otosclerosis, 1:3. • CT results in a high rate of targeted surgery in suspected otosclerosis, 1:4. • CT prevents exploratory surgery in suspected otosclerosis. • Endosteal extension of otosclerosis is predictive of lower bone conduction tresholds presurgically. • The PPV of CT diagnosis of otosclerosis was 100 %.

Cross-sectional study of unexplained white matter lesions in HIV positive individuals undergoing brain magnetic resonance imaging.

White matter (WM) abnormalities are frequently seen on brain MRI of HIV positive (HIV+) patients. We aimed to determine the prevalence of unexplained WM abnormalities and their associations with HIV disease and cardiovascular risk factors. We conducted a retrospective, cross-sectional study of brain MRI of HIV+ patients conducted between 2004 and 2009 at our center. Clinical and laboratory data were compiled, and images were independently reviewed for WM lesions. Images were obtained from 254 patients: 70% male, 53% white, 40% black, mean age 42 years, median current CD4 count 240 cells/mm(3), and 41% not taking antiretroviral therapy (ART). Hyperintense WM lesions were present in 161 patients (63.4%): 89 scans (35.0%) showed diffuse WM signal abnormality (DWMSA), 61 (24.0%) were consistent with small vessel disease (SVD, graded by Fazekas' scale), and 37 (14.6%) showed large asymmetrical focal WM lesions. SVD changes were associated with age and cardiovascular risk factors, and while cerebral SVD may be related to HIV infection, the MRI findings were not associated with HIV-related factors. The only risk factor for DWMSA was black race, and no correlation with cardiovascular risk factors, CD4 count, or clinical presentation was identified. DWMSA are therefore of uncertain neurological significance in HIV+ patients and could represent more than one clinicopathological entity.

Can contrast-enhanced ultrasound distinguish malignant from reactive lymph nodes in patients with head and neck cancers?

The purpose of this study was to investigate the utility of contrast-enhanced ultrasound in differentiating benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck. A consecutive series of 17 patients with known head and neck malignancy scheduled for neck surgery and lymph node clearance were recruited for contrast-enhanced ultrasound evaluation. Sonographic signal intensity as a function of time, comparing features of time to peak, time to arrival and time to wash-out, was quantified. The selected node was removed surgically and submitted for histology. Contrast-enhanced ultrasound examination had 100% sensitivity and 85.7% specificity for lymph node involvement. Functional analysis revealed contrast peaks significantly earlier in the malignant nodes (mean ± standard deviation) of 24.14 ± 2.7 s compared with 29.33 ± 3.4 s (p = 0.0128). Contrast-enhanced ultrasound holds promise in the detection and characterization of metastatic nodes that would not be diagnosed as abnormal on the basis of conventional ultrasound criteria.