Computed tomography and magnetic resonance imaging of pathologic conditions of the middle ear

Co-existing Paraganglioma, Cholesteatoma, and Otomastoiditis With Overlapping Imaging Features: A Diagnostic Challenge

Head and neck paragangliomas are rare neuroendocrine tumors arising from the autonomic nervous system. Imaging hallmarks of paragangliomas of the head and neck include an enhancing soft-tissue mass in the carotid space, jugular foramen, or tympanic cavity on computed tomography; a salt-and-pepper appearance on standard spin-echo magnetic resonance imaging; and an intense blush on angiography. Imaging studies depict the location and extent of tumor involvement, help determine the surgical approach, and predict operative morbidity and mortality. However, an atypical presentation of paragangliomas, especially when co-existing with other middle ear pathologies that have overlapping imaging findings, can often be misleading. Here, we report a case of simultaneous occurrence of paraganglioma, cholesteatoma, and otomastoiditis in a young adult female.

The diagnostic utility of diffusion-weighted magnetic resonance imaging and high-resolution computed tomography for cholesteatoma: A meta-analysis

Objective

The purpose of this meta-analysis was to compare the efficiency of high-resolution computed tomography (HRCT) and diffusion-weighted magnetic resonance imaging (DWI) in guiding the diagnosis of middle ear cholesteatoma in clinical practice.

Materials and methods

Cochrane Library, Medline, Embase, PubMed, and Web of Science were searched for studies that evaluated the sensitivity and specificity of HRCT or DWI in detecting middle ear cholesteatoma. A random-effects model was used to calculate and summarize the pooled estimates of sensitivity, specificity, and diagnostic odds ratios. Postoperative pathological results were considered as the diagnostic gold standard for middle ear cholesteatoma.

Results

Fourteen published articles (860 patients) met the inclusion criteria. The sensitivity and specificity of DWI when diagnosing cholesteatoma (regardless of type) were 0.88 (95% confidence interval [CI], 0.80-0.93) and 0.93 (95% CI, 0.86-0.97), respectively, while those of HRCT were 0.68 (95% CI, 0.57-0.77) and 0.78 (95% CI, 0.60-0.90), respectively. Notably, the sensitivity and specificity levels of DWI were similar to those of HRCT (p = .1178 for sensitivity, p = .2144 for specificity; pair-sampled t tests). The sensitivity and specificity of DWI or HRCT for the diagnosis of primary cholesteatoma were 0.78 (95% CI, 0.65-0.88) and 0.84 (95% CI, 0.69-0.93), respectively, while that for recurrent cholesteatoma were 0.93 (95% CI, 0.61-0.99) and 0.94 (95% CI, 0.82-0.98), respectively.

Conclusion

DWI and HRCT have similar levels of high sensitivity and specificity in detecting various cholesteatomas. Also, the diagnostic efficiency of HRCT or DWI for recurrent cholesteatoma is identical to that of primary cholesteatoma. Therefore, HRCT may be used in clinical settings to reduce the use of DWI and save clinical resources.

Lay summary

Data on the use of diffusion-weighted magnetic resonance imaging and high-resolution computed tomography in the diagnosis of cholesteatoma were obtained through a literature search. They were analyzed to guide the clinical diagnosis and treatment of cholesteatoma.

Level of evidence

NA.

Imaging analysis of dural exposure in cholesteatomas with a skull base defect

PURPOSE

Dural exposure during cholesteatoma surgery can pose a risk of cerebrospinal fluid leakage or residual disease. Therefore, delicate handling of the area surrounding the bone defect in the cranial fossa is required. However, in small-sized defects, preoperative prediction of dural exposure can be challenging. This study aimed to evaluate the diagnostic value of computed tomography (CT) for preoperative prediction of cholesteatoma-related dural exposure in bone discontinuities in the skull base.

METHODS

We evaluated serial high-resolution CT images showing bone density discontinuities in the middle cranial fossa (MCF) requiring mastoidectomy for cholesteatoma. The CT and intraoperative findings were analyzed retrospectively. We evaluated the length between the superior margins of the bone density discontinuities using coronal CT planes. Receiver operating characteristic (ROC) curves were constructed to determine the optimal cut-off values.

RESULTS

We extracted data from 107 bone density discontinuities, among which 54 (50.5%) showed dural exposure intraoperatively. Discontinuities with dural exposure (n = 54) had significantly greater lengths than did those without (n = 53) (p < 0.001, Wilcoxon rank-sum test). The area under the curve was 0.9780 according to the ROC analysis, and the optimal cut-off value was determined to be 2.99 mm (sensitivity 92.59%; specificity 94.34%).

CONCLUSION

A bone density discontinuity length of > 2.99 mm in the MCF on coronal CT plane is a reliable diagnostic marker for cholesteatoma-related dural exposure. Thus, preoperative high-resolution CT analysis can inform optimal surgical preparation and planning before manipulating the area surrounding the osteolytic lesion in the MCF.

The Value of Ultrashort Echo Time MR in Depiction of the Eustachian Tube at 3 Tesla

OBJECTIVES

To investigate the feasibility of ultrashort echo time (UTE) imaging in the visualization of Eustachian tubes (ETs).

METHODS

The local institutional review board approved the study protocol. Twenty volunteers were involved in this study. The scanning scheme consisted of T2-sampling perfection with application-optimized contrasts by using different flip angle evolutions (T2-SPACE) MR imaging with water excitation, a UTE scan with a prototype sequence and a CT scan. The UTE images were compared with both the T2-SPACE and CT images. The quality of the images was rated by two radiologists blindly. Interobserver agreement was assessed using the kappa statistic. Statistical analysis was performed using SPSS software (version 17, SPSS Inc.). A value of p < 0.05 was considered statistically significant.

RESULTS

For all subjects, the T2-SPACE images successfully displayed the cartilaginous part of the ET (Fig. 1). The CT images fully showed the bony part of the ET for all the subjects (Fig. 2). The UTE images successfully displayed both the cartilaginous and bony parts of the ET (Fig. 3). However, the UTE images showed the cartilaginous and bony portions of the ET as a whole.

CONCLUSIONS

By analyzing the depiction of the ET from UTE images and comparing it with that from MR and CT images, we found that UTE images could display not only the cartilaginous structure of the ET that cannot be seen by conventional MR sequences, but also the bony structure that previously could only be seen on CT images. This imaging modality could help provide a convenient and new method to display the overall shape of the ET.

Construction of an MRI-based decision tree to differentiate autoimmune and autoinflammatory inner ear disease from chronic otitis media with sensorineural hearing loss

Autoimmune and autoinflammatory inner ear diseases (AIED/AID) are characterized by the symptom of sensorineural hearing loss (SNHL). To date, standardized diagnostic tools for AIED/AID are lacking, and clinically differentiating AIED/AID from chronic otitis media (COM) with SNHL is challenging. This retrospective study aimed to construct a magnetic resonance imaging (MRI)-based decision tree using classification and regression tree (CART) analysis to distinguish AIED/AID from COM. In total, 67 patients were enrolled between January 2004 and October 2019, comprising AIED/AID (n = 18), COM (n = 24), and control groups (n = 25). All patients underwent 3 T temporal bone MRI, including post-contrast T1-weighted images (postT1WI) and post-contrast FLAIR images (postFLAIR). Two radiologists evaluated the presence of otomastoid effusion and inner ear contrast-enhancement on MRI. A CART decision tree model was constructed using MRI features to differentiate AIED/AID from COM and control groups, and diagnostic performance was analyzed. High-intensity bilateral effusion (61.1%) and inner ear enhancement (postFLAIR, 93.8%; postT1WI, 61.1%) were the most common findings in the AIED/AID group. We constructed two CART decision tree models; the first used effusion amount as the first partitioning node and postT1WI-inner ear enhancement as the second node, whereas the second comprised two partitioning nodes with the degree of postFLAIR-enhancement of the inner ear. The first and second models enabled distinction of AIED/AID from COM with high specificity (100% and 94.3%, respectively). The amount of effusion and the degree of inner ear enhancement on MRI may facilitate the distinction between AIED/AID and COM with SNHL using decision tree models, thereby contributing to early diagnosis and intervention.

Rare Diseases of the Middle Ear and Lateral Skull Base

Otalgia, otorrhea and hearing loss are the most common ear-related symptoms that lead to the consultation of an otolaryngologist. Furthermore, balance disorders and affections of the cranial nerve function may play a role in the consultation. In large academic centres, but also in primary care, the identification of rare diseases of the middle ear and the lateral skull base is essential, as these diseases often require interdisciplinary approaches to establish the correct diagnosis and to initiate safe and adequate treatments. This review provides an overview of rare bone, neoplastic, haematological, autoimmunological and infectious disorders as well as malformations that may manifest in the middle ear and the lateral skull base. Knowledge of rare disorders is an essential factor ensuring the quality of patient care, in particular surgical procedures. Notably, in untypical, complicated, and prolonged disease courses, rare differential diagnoses need to be considered.

Osteolytic lesions on the os petrosum of a Bronze Age individual from La Llana cave (Northern Spain) compatible with a possible case of otitis media. A multifaceted methodological approach

OBJECTIVE

To encourage the use of different methodological approaches for the identification of paleopathological lesions and to evaluate osteolytic lesions found on a temporal bone from La Llana cave (Spain).

MATERIALS

Cranial remains recovered from from La Llana cave (Spain) dated to the Bronze Age, 3300 ± 25 BP (1631-1509 cal BC).

METHODS

The cranium underwent macroscopic, microscopic and computed tomography scan examinations.

RESULTS

The Tegmen tympani of the left temporal bone is present but is missing on the right. Both cochleae are intact. Both the right and left temporal bones display osteolytic lesions, with the left Tegmen tympani displaying deep and profuse pits on the endocranial surface, exposing the ear channel.

CONCLUSIONS

The lesions are compatible with otitis media (atticitis). By using different methods of analysis, the presence and effects of infection were identified.

SIGNIFICANCE

This systematically described case contributes to our understanding of disease in the past and describes otitis-related lesions in archeological contexts for comparative purposes.

LIMITATIONS

The fragmentary and damaged cranial remains rendered evaluation difficult and diagnosis tentative.

SUGGESTIONS FOR FURTHER RESEARCH

The use of different approaches to diagnose otitis media in archeological skeletal collections is recommended to improve the knowledge of health status and lifestyle of past populations.

Isolated Incudostapedial Cholesteatomas: Unique Radiologic and Surgical Features

OBJECTIVES

Congenital cholesteatomas originate from epithelial tissue present within the middle ear in patients with an intact tympanic membrane, no history of otologic surgery, otorrhea, or tympanic membrane perforation. They are diagnosed by a pearl-like lesion on otoscopy and computed tomography (CT) scan showing an expansile soft-tissue mass. We describe a series of patients with no prior otologic history presenting with progressive unilateral conductive hearing loss and normal otoscopy. The CT scans showed ossicular erosion without obvious soft-tissue mass. Surgery confirmed incudostapedial erosion found to be cholesteatoma. In this study, we characterize the clinical course of patients diagnosed with isolated incudostapedial cholesteatoma (IIC) and review possible pathologic mechanisms.

METHODS

Retrospective review of IIC cases treated by the Department of Pediatric Otolaryngology, Rady Children's Hospital, San Diego, 2014 to 2020. Data included patient demographics, clinical features, imaging, surgical findings, and audiologic data.

RESULTS

Five patients were diagnosed with IIC (3 [60%] female; mean age at presentation 10.7 years [range 5.5-16.0]). All patients presented with postlingual unilateral conductive hearing loss and normal otoscopy without any past otologic history; delay in diagnosis ranged from 4 months to several years. The CT scans showed ossicular chain erosion with an absent long process of the incus and/or stapes superstructure. All patients underwent middle ear exploration, revealing a thin layer of cholesteatoma in the incudostapedial region, confirmed by histopathology. Mean preoperative speech reception threshold was 55 dB and improved to a mean of 31 dB in the 4 patients who underwent ossicular chain reconstruction.

CONCLUSION

Isolated incudostapedial cholesteatoma should be included as a possible etiology in pediatric patients with insidious onset of unilateral conductive hearing loss with normal otoscopy, unremarkable otologic history, and a CT scan showing ossicular abnormality/disruption without notable middle ear mass. These patients should be counseled preoperatively regarding the possibility of cholesteatoma and should undergo middle ear exploration with possible ossiculoplasty.

Occult otitis media in dogs with chronic otitis externa - magnetic resonance imaging and association with otoscopic and cytological findings

BACKGROUND

Identification of perpetuating factors, such as otitis media (OM), is important for the successful management of canine chronic otitis externa (OE).

HYPOTHESIS/OBJECTIVES

Occult OM can occur in cases of chronic OE; a focused magnetic resonance imaging (MRI) examination is a useful tool in their management.

ANIMALS

One hundred twenty one client-owned dogs presented for investigation and treatment of chronic OE between 2009 and 2018.

METHODS AND MATERIALS

Mixed retrospective (74 dogs) and prospective (47 dogs) study of chronic OE cases without neurological signs, describing the MRI, otoscopic and cytological findings; comparing cases with and without MRI evidence of OM.

RESULTS

A total of 123 MRI studies were analysed (two dogs scanned twice). A short, focused MRI scan allowed detection of inflammation of the mucosal bulla lining as well as excellent discrimination between avascular material and vascularised soft tissue in the tympanic cavity. OM was found in 41 of 197 (21%) ears with chronic otitis externa. On otoscopy, the tympanic membrane was intact in six of 41 ears (15%), ruptured in 16 of 41 (39%) and not visible in 14 of 41 (34%) [no data in five of 41 (12%)]. Analysis of cytological findings showed that the presence of rods was only associated with an increased likelihood of OM when found together with inflammatory cells.

CONCLUSIONS AND CLINICAL IMPORTANCE

Occult OM is a not uncommon finding on MRI of dogs with chronic OE. A targeted MRI study ("bulla mini-scan") may be useful as part of the clinical investigations.

Acute mastoiditis: 20 years of experience with a uniform management protocol

OBJECTIVES

To characterize the clinical presentation of pediatric patients who, upon AM diagnosis, also had imaging-diagnosed ICCs (ID-ICCs); to define the group of AM patients at risk of developing ID-ICCs; and to update knowledge about organisms causing AM.

STUDY DESIGN

Analysis of all AM patients admitted between 1997 and 2018 and treated according to an obligatory protocol including both brain imaging and sampling for bacterial culture upon clinical diagnosis of AM.

RESULTS

Of 166 admitted patients (0.5-19 years old) 22 (13%) already had ID-ICCs. In patients who, on admission, had already received antibiotics for acute otitis media (AOM) and also had CRP (C-reactive protein) levels above 93.5 mg/L, the risk of ID-CC was increased by 22.5-fold (P < 0.0001). Bacterial culture results were available for all patients and were positive in 115 (69%). Organisms most commonly found in patients without prior antibiotic treatment were group A Streptococcus pyogenes (53%), Streptococcus pneumoniae (23%), and Haemophylus influenzae (11%), while with prior antibiotic treatment they were Fusobacterium necrophorum (21%), Streptococcus pyogenes (18%) and Pseudomonas aeruginosa (18%).

CONCLUSIONS

Since the risk of ID-ICC in patients with the abovementioned CRP and prior antibiotic treatment was significantly higher than in the others, these high-risk patients should undergo diagnostic imaging on admission. Antibiotic treatment prior to AM development may promote growth of non-AOM pathogen.

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

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

[The algorithm of the treatment and diagnostic strategy for the treatment the children presenting with acute mastoiditis]

This article was designed to report the results of the analysis of the cases of chronic otitis media complicated by mastoiditis in the children admitted to the Morozovskaya City Children's Clinical Hospital for the examination and treatment during the period from 2009 till 2017. The objective of the present study was to evaluate the clinical significance and the optimal time schedule of computed tomography (CT) of the temporal bones in the patients with suspicion of mastoiditis for the determination of the indications for their surgical treatment. All the patients were divided into three groups differing in the severity of clinical manifestations of the disease. A special algorithm of the treatment and diagnostic strategy was developed for the management of the patients included in each group that made possible the structured approach to the choice and performance of the treatment and diagnostic procedures.

Temporal bone computed tomography findings associated with feasibility of endoscopic ear surgery

PURPOSE

There are no formal radiologic criteria to stratify patients for transcanal (TEES) or transmastoid endoscopic ear surgery for resection of cholesteatoma. We aim to determine 1) whether standard preoperative computed tomography (CT) findings are associated with the need for conversion to a transmastoid approach and 2) the amount of time added for conversion from TEES to transmastoid techniques.

MATERIALS AND METHODS

Retrospective chart review of consecutive pediatric and adult cases of TEES for primary cholesteatoma from 2013 through 2015 (n=52). TEES cases were defined as endoscope-only procedures that did not require a transmastoid approach (n=33). Conversion cases were defined as procedures that began as TEES however, required conversion to a transmastoid approach due to the inability to complete cholesteatoma removal (n=19). Preoperative CT findings and total operating room (OR) times of TEES and conversion cases were compared.

RESULTS

Preoperative CT scan characteristics that were associated with conversion included tegmen erosion (p=0.026), malleus erosion (p<0.001), incus erosion (p=0.009), mastoid opacification (p=0.009), soft tissue opacification extending into the aditus ad antrum (p=0.009) and into antrum (p=0.006). Total OR time for TEES cases was significantly shorter than conversion cases (median 143min versus 217min, p<0.001).

CONCLUSIONS

Preoperative CT findings, notably extension of soft tissue in the aditus ad antrum, antrum and mastoid, are associated with need for conversion to transmastoid technique to achieve removal of cholesteatoma. Endoscope-only cases were significantly faster than cases that required conversion to a transmastoid approach.

Does incidental mastoid opacification on computerized tomography necessitate referral to ENT?

OBJECTIVE

The prevalence of incidental temporal bone disease on magnetic resonance imaging has been widely reported in the medical literature. Despite this, there currently is little evidence regarding incidental otological disease on computerized tomography (CT). Thus, the study aimed to review the CT prevalence of asymptomatic adult ear disease and evaluate the appropriateness of ear, nose, and throat (ENT) referral following its discovery.

STUDY DESIGN

Retrospective observational study of 468 CT scans.

METHODS

All CT head scans performed between January 2015 and January 2016 containing the keyword mastoid in the radiological report initially were recruited for the study. Scans performed in the pediatric population following head trauma or for otological indications were excluded, leaving 468 eligible radiological images. The presence of prior otological disease or referral subsequently was established using electronic patient records.

RESULTS

Mastoid and/or middle ear opacification was noted to be present in 62 patients (13%). Of these patients, 10 subsequently were found to have prior otological intervention or review. Following exclusion of these patients, the rate of incidental temporal bone disease was recorded as 11%.

CONCLUSION

Data from this study suggests that incidental findings in an asymptomatic individual do not necessitate referral or further intervention. Furthermore, it is the author's recommendation that radiological findings be closely correlated with clinical examination to reduce false diagnosis and inappropriate referral to ENT.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2860-2865, 2017.

Indications and radiological findings of acute otitis media and its complications

Most cases of acute otitis media resolve with antibiotics and imaging is not required. When treatment fails or a complication is suspected, imaging plays a crucial role. Since the introduction of antibiotic treatment, the complication rate has decreased dramatically. Nevertheless, given the critical clinical relevance of complications, the importance of early diagnosis is vital. Our objective was to review the clinical and radiological features of acute otitis media and its complications. They were classified based on their location, as intratemporal or intracranial. Imaging makes it possible to diagnose the complications of acute otitis media and to institute appropriate treatment. Computed tomography is the initial technique of choice and, in most cases, the ultimate. Magnetic resonance is useful for evaluating the inner ear and when accurate evaluation of disease extent or better characterization of intracranial complications is required.

[Inflammatory diseases of the petrous portion of the temporal bone]

CLINICAL/METHODICAL ISSUE

Inflammatory lesions of the petrous portion of the temporal bone are very common and can be followed by cerebral complications.

PRACTICAL RECOMMENDATIONS

Thin layer computed tomography (CT) is useful for detecting bony changes of the temporal bone and contrast-enhanced magnetic resonance imaging (CE MRI) is a sensitive method for detecting cerebral complications.

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.

Intraoperative Cone-Beam Computed Tomography and Multi-Slice Computed Tomography in Temporal Bone Imaging for Surgical Treatment

Objective

Conventional computed tomography (CT) imaging is the standard imaging technique for temporal bone diseases, whereas cone-beam CT (CBCT) imaging is a very fast imaging tool with a significant less radiation dose compared with conventional CT. We hypothesize that a system for intraoperative cone-beam CT provides comparable image quality to diagnostic CT for identifying temporal bone anatomical landmarks in cadaveric specimens.

Study Design

Cross-sectional study.

Setting

University tertiary care facility.

Subjects and Methods

Twenty cadaveric temporal bones were affixed into a head phantom and scanned with both a prototype cone-beam CT C-arm and multislice helical CT. Imaging performance was evaluated by 3 otologic surgeons and 1 head and neck radiologist. Participants were presented images in a randomized order and completed landmark identification questionnaires covering 21 structures.

Results

CBCT and multislice CT have comparable performance in identifying temporal structures. Three otologic surgeons indicated that CBCT provided statistically equivalent performance for 19 of 21 landmarks, with CBCT superior to CT for the chorda tympani and inferior for the crura of the stapes. Subgroup analysis showed that CBCT performed superiorly for temporal bone structures compared with CT. The radiologist rated CBCT and CT as statistically equivalent for 18 of 21 landmarks, with CT superior to CBCT for the crura of stapes, chorda tympani, and sigmoid sinus.

Conclusion

CBCT provides comparable image quality to conventional CT for temporal bone anatomical sites in cadaveric specimens. Clinical applications of low-dose CBCT imaging in surgical planning, intraoperative guidance, and postoperative assessment are promising but require further investigation.

Soft tissue attenuation in middle ear on HRCT: Pictorial review

Middle ear disease is a common clinical entity; imaging, especially High resolution Computed Tomography (HRCT), plays a crucial role in diagnosis and assessing the disease extent, helping to decide appropriate management. Temporal bone imaging is challenging and involves thorough understanding of the anatomy, especially in relation to HRCT imaging. Most of the middle ear pathologies appear as “soft tissue” on imaging. Careful analysis of the soft tissue on the HRCT is crucial in achieving the right diagnosis; clinical information is essential and the imaging findings need correlation with clinical presentation and otoscopic findings. The purpose of this pictorial essay is to enlist the pathologies that present as soft tissue in middle ear and to provide a structured and practical imaging approach that will serve as a guide for confident reporting in daily practice.

Acute mastoiditis--the role of radiology

Acute mastoiditis is a commonly occurring condition in children and adults, and one that most radiologists will come across at some point during their on-call duties. Acute mastoiditis is usually clinically apparent. However, the complications, especially the intracranial ones, can be more insidious and may have fatal consequences. Therefore, it is imperative that the radiologist is well versed in identifying these. Local spread of infection from the mastoids and middle ear cleft may occur via four routes: bone erosion, thrombophlebitis, periphlebitis, and via the anatomical pathways. The role of radiology is largely to demonstrate the complications of mastoiditis, which can be clinically occult and are often serious; this article will highlight these complications.

Diagnosis of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a rather common disease in children, but its symptoms are often subtle and non-specific and this may result in overlooking a correct diagnosis. In turn, a missed diagnosis of CRS prevents a correct management to be performed and is associated with uneffective investigations and improper treatments. Actually, when CRS symptoms, which are mainly nasal congestion and obstruction, nasal discharge, facial pain, cough, and halitosis, are correctly assessed, the clinical diagnosis of CRS may be achieved, and confirmation may be obtained by imaging criteria or nasal fibroendoscopy. In imaging, computed tomography (CT) is the first choice technique for the evaluation of CRS and is able to provide an anatomic road map when surgery is required. Magnetic resonance imaging (MRI) of the sinuses, orbits, and brain should be performed whenever extensive or multiple complications of sinusitis are suspected. Also for middle ear disorders, CT is the first choice because it detects opacification of the middle ear cavity and mastoid cells, presence of fluids or debris, and allows the ossicular chain and the cortical bone of the mastoid to be evaluated. Another important diagnostic issue is the need to look for disorders that are frequently associated with CRS, such as obstructive sleep apnea syndrome (OSAS), that has some recognized risk factors in adenotonsillar hypertrophy, craniofacial anomalies, obesity, and neuromuscular disorders. Other associated disorders requiring investigation are recurrent or persistent otitis media and difficult asthma.

Effects of middle ear lesions on pre and postoperative hearing outcomes in patients with chronic otitis media

Background and Objectives

The purpose of this study was to evaluate the effects of middle ear lesions on pre and postoperative hearing in patients with chronic otitis media (COM) and to assess the relationship between various prognostic factors and pre and postoperative hearing using more than 2000 COM surgery records retrieved from a computerized database released by the Korean Otologic Society in 2005.

Subjects and Methods

Data of 2312 COM surgeries, which had been conducted by a single surgeon from 1989 to 2009, were reviewed retrospectively. Mean preoperative and postoperative air-bone gap (ABG) was analyzed using a four-frequency (500, 1000, 2000, and 3000 Hz) pure tone average (PTA). Pre and postoperative ABGs were compared with regard to several prognostic factors, including disease duration, age, Eustachian tube function, existence of otorrhea, size of tympanic membrane perforation, degree of ossicular destruction, presence of cholesteatoma, and its type.

Results

Mean pre and postoperative ABGs of PTA in the 2079 cases studied were 27.88±13.33 dB and 17.38±15.64 dB, respectively, with a hearing success rate of 69%. The results suggested that preoperative ABGs were affected by Eustachian tube function, Griffin grade, presence of cholesteatoma and its type, and the degree of ossicular destruction. Hearing gains differed significantly among the groups when compared with factors of Griffin grade, presence or type of cholesteatoma, and the degree of ossicular destruction.

Conclusions

Many factors affected pre and postoperative ABGs and postoperative hearing outcomes. These results will be useful for designing future clinical studies on COM surgery, as well as for surgical planning and patient counseling in clinical practice.

New insights into mechanism of Eustachian tube ventilation based on cine computed tomography images

There is debate concerning the mechanism of Eustachian tube (ET) ventilation. While a mechanism of complete opening has been advocated previously, sequential contraction of the levator veli palatini and medial pterygoid muscles followed by the tensor veli palatini and lateral pterygoid muscles may produce a transient sequential opening mechanism, allowing an air bolus to traverse the ET. This may explain confusion surrounding sonotubometry reports that not every swallow leads to sound passage in normal subjects. We hypothesize that the ET may not need to open completely when ventilating the middle ear; rather, a discrete air bolus can pass through it. Five normal and five disordered subjects underwent low-radiation dose cine computed tomography (CT) scans of the ET. Sixteen contiguous 2.5 mm slice locations were chosen through a 4 cm area in the nasopharynx that were parallel to and encompassed the entire ET. Twelve images were acquired at each slice over 4.8 s during swallowing and other tasks. Serial images were analyzed. An air bolus was observed passing through the ET in the normal subjects, but not the subject with ET dysfunction. Medial and lateral pterygoid contractions were also observed. A new hypothetical mechanism of transient sequential ET ventilation is presented. This is not a definitive conclusion, as the number of scans taken and maneuvers used was limited. Improved understanding of ET ventilation may facilitate management of middle ear disease as treatment evolves from ventilatory tube placement to ET manipulation.

Congenital incudostapedial anomalies in adult stapes surgery: a case-series review

OBJECTIVES

The management of developmental anomalies of the ossicular chain and otic capsule in stapes surgery tests the otologist's diagnostic skills and flexibility in technique and prosthesis choice. We review our experience in managing various incudostapedial developmental anomalies discovered during middle ear exploration for suspected otosclerosis in adult patients.

DESIGN

A retrospective case-series review was used.

SETTING

The study was set at a military tertiary referral center.

PATIENTS AND OTHER PARTICIPANTS

A review of 185 stapes procedures yielded 8 cases of identified congenital anomalies of the stapes or incudostapedial complex including congenital absence of the oval window with malformed incus and stapes, columellar-type stapes with promontory fixation, stapes superstructure fixation to the fallopian canal, and malformed incus with stapes superstructure fixation to the promontory.

INTERVENTIONS

The developmental anatomy and surgical technique in each case were reviewed. The surgical technique used in each case varied depending on the specific ossicular abnormality found and whether both the stapes and incus were affected.

MAIN OUTCOME MEASURES

Comparison of preoperative and postoperative audiometric testing results was performed.

RESULTS

All 8 ears (7 patients) that underwent a stapes procedure for either an isolated congenital stapes anomaly or a combined incudostapedial anomaly had a favorable hearing outcome, with 7 ears improving to within 10-dB and 1 ear to within 13-dB air-bone gap on postoperative audiometry.

CONCLUSIONS

Despite unanticipated findings of congenital anomalies of the stapes and incus during middle ear exploration for conductive hearing loss, a flexible management approach can lead to successful hearing outcomes.

A histological examination in the cases of initial diagnosis as chronic otitis media with a polypoid mass in the external ear canal

OBJECTIVE

to analyse a large series of patients with initial diagnosis of chronic otitis media (COM) with a polypoid mass in the external ear canal (EAC).

MATERIAL AND METHODS

185 consecutive patients with COM were evaluated; 75 showed a polypoid mass in the EAC.

RESULTS

In 65 out of the 75 (86.7%) patients, histological examination after mastoidectomy revealed cholesteatoma. In the remaining 10 (13.3%) cases, the histological diagnosis was: glomus tumor, melanoma, mucosal adenoma, fibrous dysplasia, squamous cell carcinoma, adenoma of the endolymphatic sac, encephalocele, and tuberculosis. One patient (glomus tumor) had undergone biopsy of the polypoid mass twice preoperatively and the initial histological diagnosis was "inflammatory polyp". Therefore, we examined the temporal bones with a glomus tumor diagnosis from the temporal bone collection of the House Ear Institute. In 1560 temporal bones, a glomus tympanicum was found in 6. In four cases, the tumor extended to the EAC mimicking a polyp covered by squamous epithelium.

CONCLUSION

A significant percentage of polyps in COM may be the tip of an 'iceberg'. CT-scan and MRI techniques may be helpful but not always accurate, and biopsies have certain risks. Increased clinical suspicion may limit misdiagnosis and inappropriate management.

Three-Dimensional Image Analysis of the Temporal Bone in Patients with Unilateral Attic Cholesteatoma

We determined temporal bone anatomy in patients with unilateral attic cholesteatoma. We compared the affected and normal ears of ten patients with unilateral attic cholesteatoma using three-dimensionally reconstructed high-resolution computed tomography images of the temporal bone. We determined the eustachian tube angle, eustachian tube length, sizes of the tympanic orifice of the eustachian tube, the pars flaccida, and the mastoid cavity, and distances of the pars flaccida and the tympanic orifice of the eustachian tube from the epitympanic roof. No significant differences were found between the normal and affected ears with regard to the size of the eustachian tube orifice, eustachian tube length or distances of the pars flaccida and the tympanic orifice of the eustachian tube from the epitympanic roof. By contrast, the mastoid cavity and the eustachian tube angle were significantly larger in the normal ears than in the affected ears [mean, 6.99 cm3 (S.D., 4.9 cm3) vs. 1.28 cm3 (0.81 cm3) and 16.7° (4.12°) vs. 13.89° (5.30°), respectively]. The pars flaccida was significantly smaller in the normal ears [1.07 cm (0.31 cm)] than in the affected ears [2.19 cm (0.77 cm)]. The inherent anatomy of the eustachian tube may be particularly important in the formation of attic cholesteatomas.

The value of scutum erosion in the diagnosis of temporal bone cholesteatoma

CONCLUSIONS

Scutum erosion has an important role in the diagnosis of attic cholesteatoma, but it does not appear in other types of cholesteatoma in temporal bone. Without scutum erosion, the existence of cholesteatoma cannot be excluded.

OBJECTIVE

To evaluate the value of scutum erosion in the diagnosis of cholesteatoma in temporal bone and its limitations.

SUBJECTS AND METHODS

CT scanning and otoscopy were used in all patients who were suspected of developing, or were probably diagnosed with, cholesteatoma in temporal bone. The condition of the scutum was recorded by otoscopy, CT scanning and surgical findings in all patients with cholesteatomas.

RESULTS

Scutum erosion can be shown in attic retraction with cholesteatoma at an early stage, but not in marginal perforation or with posterior retraction with cholesteatoma, or in central perforation or intact tympanic membrane with cholesteatoma, even in relatively late stages.

Diffusion-weighted MR imaging for evaluation of pediatric recurrent cholesteatomas

OBJECTIVE

To compare the efficiency of diffusion-weighted MR imaging (MRI) vs. high resolution CT in predicting recurrent or residual cholesteatoma in children who underwent prior middle ear surgery.

DESIGN

Prospective study.

SETTING

Tertiary care university hospital.

PATIENTS

Seventeen patients (4 with 2 recurrences) aged 5-17 years (mean 11.4) previously surgically treated for a cholesteatoma of the middle ear, were included for follow-up with systematic CT scan and MRI, between 2005 and 2007.

METHODOLOGY

CT scan was performed on a Siemens Somaton 64 (0.5/0.2 mm slices reformatted in 0.5/0.3 mm images), parallel and perpendicular to the lateral semi-circular canal for each ear (100 mmx100 mm FOV). MRI was undertaken on a Siemens Avanto 1.5 T unit, with an adapted protocol for young children. Diagnosis of recurrent cholesteatoma was based on the evidence of a hyperintense image at B1000 on diffusion-weighted images. Results of CT scan and MRI were compared with operative diagnosis.

RESULTS

Nine patients had a positive MRI, among which 8 had cholesteatoma confirmed during revision surgery. In the 12 negative MRI cases, 5 were positive on revision surgery. None of these lesions was over 3mm. Two of them were diagnosed on the CT scan. CT scan alone had a positive predictive value of 75%, and a negative predictive value of 58%.

CONCLUSION

Diffusion-weighted MRI is associated with a high positive predictive value for the detection of recurrent cholesteatoma. CT scan remains the first choice imaging technique. In case of doubtful CT scan, diffusion-weighted MRI could confirm a recurrence or, when negative, avoid second-look surgery.

Radiologic evaluation of the ear anatomy in pediatric cholesteatoma

The aim of the study was to describe computed tomography (CT) findings in middle ear cholesteatoma in pediatric patients. A cohort of 32 children with cholesteatoma (3-14 years old) entered the study. From them, 30 presented acquired cholesteatoma (AC), and 2 presented congenital cholesteatoma. All of the children were investigated using CT before surgery of the middle ear and mastoid. Computed tomography was performed with 1- or 2-mm axial and coronal sections of both temporal bones. Nineteen children with AC (63.3%) revealed a diffuse soft-tissue density isodense with muscle, whereas in 6 of them, the mass mimicked inflammation. The remaining revealed localized soft-tissue mass with partially lobulated contour. In AC, ossicular erosion was detected in 23 cases (76.7%), abnormal pneumatization in 19 cases (63.3%), and erosion-blunting of spur and enlargement of middle ear or mastoid in 8 cases (26.7%). The 2 congenital cholesteatomas revealed soft-tissue mass with polypoid densities, while a semicircular canal fistula was detected in one of them. High-resolution CT facilitates early diagnosis and appropriate treatment of pediatric cholesteatoma by assessing the anatomic abnormalities and the extent of disease, which are crucial in middle ear and mastoid surgery.

Mastoiditis on MRI: Fact or Artifact?

Fluid signal in the mastoid can be an incidental finding on T2-weighted magnetic resonance imaging and often is interpreted as mastoiditis by radiologists. This study examines 28 consecutive cases of such erroneously diagnosed “mastoiditis” and documents the presence or absence of otologic symptoms and clinical signs. We found a very low prevalence of otologic symptoms or pathology and no cases of mastoiditis in these patients, and we determined that magnetic resonance imaging is not an effective screening modality for mastoiditis. We also reviewed the literature on current diagnostic criteria for mastoiditis and propose alternative terminology to replace the use of excessively alarming terms such as “mastoiditis” unless they apply to that specific clinical diagnosis.

Progressive massive osteolysis secondary to benign squamous epithelial colonisation in chronic osteomyelitis

Although the rare complication of squamous cell carcinoma in chronic osteomyelitis is well known, benign squamous epithelial proliferation can also occur, causing osteolysis and fracture. The radiological and correlated pathological features of osteolysis from this benign complication of chronic osteomyelitis are presented.

[Benign and malignant lesions in the region of the inner ear and cerebellopontine angle]

Tumorous lesions in the region of the inner ear and cerebellopontine angle are very rare and can be classified into benign and malignant disease forms. This contribution presents and explains the CT and MRI characteristics of these tumors.High-resolution computed tomography (HRCT) in the axial projection is applied for evaluation in the high-resolution bone window. The coronary slices can be reconstructed from the axial datasets or in individual cases examined in the coronary plane.HRCT excellently demonstrates osseous lesions and in individual cases - e.g., exostoses - it can simply suffice to perform HRCT of the temporal bone, while HRCT is also excellent for detecting osseous lesions to determine whether the tumor is benign or malignant.MRI, on the other hand, excellently shows the extent of tumor spread because of its superb soft tissue contrast. Consequently, HRCT and MRI images of the inner ear and cerebellopontine angle provide meaningful information for visualization and classification of tumorous lesions. The two methods should not be considered as competing but rather as complementary and among other aspects exert considerable influence on the therapeutic approach.

Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs

The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.

INFLAMMATORY POLYP IN THE MIDDLE EAR WITH SECONDARY SUPPURATIVE MENINGOENCEPHALITIS IN A CAT

A 15-month-old male Maine Coon Cat presented with persistent auricular discharge and progressive head tilt, ataxia, and loss of blink on the right side. Using computed tomography a hyperattenuating, contrast-enhancing material within a thickened right tympanic bulla and contrast enhancement of the adjacent cerebellum were identified. Marked suppurative inflammation was identified on cerebrospinal fluid analysis with no growth on bacterial culture. Ventral bulla osteotomy was performed to remove a soft tissue mass, and an inflammatory polyp with chronic severe suppurative inflammation was confirmed using histology. Staphylococcus auricularis was grown on aerobic culture and Fusobacterium necrophorum and Peptostreptococcus anaerobius were grown on anaerobic culture. The cat was treated for 10 weeks with amoxicillin/clavulinic acid and metronidazole. Dramatic improvement in body weight, appetite, energy level, balance, and resolution of right-sided facial paralysis were noted, but the cat retained a head tilt.

Clinical significance of incidental magnetic resonance image abnormalities in mastoid cavity and middle ear in children

OBJECTIVE

Magnetic resonance imaging of the head may reveal incidental findings in paranasal sinuses. The purpose of this study was to discover whether similar changes could be identified in the mastoid cavity and middle ear as well.

METHODS

A group of 50 children undergoing magnetic resonance imaging of the head for suspected intracranial pathology were prospectively gathered. Their parents completed a questionnaire concerning each child's medical history connected with acute otitis media. Otoradiologists evaluated the pictures for mastoid cavity and middle ear and paranasal sinus abnormalities.

RESULTS

In six (12%) children, magnetic resonance imaging detected abnormalities resembling acute inflammatory changes, although none had had acute otitis media during the preceding last 3 months. Abnormalities detected in the paranasal sinuses were not correlated with abnormalities in the mastoid cavity and middle ear.

CONCLUSIONS

High signal intensity in magnetic resonance images from the mastoid cavity and middle ear may be incidental and without any clinical significance. These findings must be interpreted together with knowledge of the child's medical condition and clinical examination of the ears.

Imaging of complications of acute mastoiditis in children

Acute mastoiditis is a serious complication of acute otitis media in children. Suppurative disease in the mastoid region occasionally spreads to the adjacent dura mater of the posterior and middle cranial fossae and the sigmoid sinus by means of thrombophlebitis, osseous erosion, or anatomic pathways, producing intracranial complications. Computed tomography (CT) should be performed early in the course of the disease to classify the mastoiditis as incipient or coalescent and to detect intracranial complications. On the basis of the clinical features and imaging findings, the disease is managed conservatively with intravenously administered antibiotics or treated with mastoidectomy and drainage plus antibiotic therapy. CT is therefore a decisive diagnostic tool in determining the type of therapy. In addition, magnetic resonance imaging is performed in patients with clinical symptoms or CT findings suggestive of intracranial complications because of its higher sensitivity for detection of extraaxial fluid collections and associated vascular problems.