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.     

Pneumatization of the sphenoid sinus in children evaluated by magnetic resonance imaging

Previous studies concerned with the normal development of the sphenoid sinus have reported that the onset of initial pneumatization varies from 6 months to 4 years of life, and that the pneumatization is completed by 12 to 14 years of age. This study was designed to evaluate the age-related development of the sphenoid sinus pneumatization in children using magnetic resonance (MR) imaging technique. MR images of the sphenoid sinus in 152 children, ages 2 months to 163 months, were retrospectively reviewed. The degree of pneumatization was classified into four grades as 0, 1, 2, and 3 in axial images, and into five grades as 0, 1, 2, 3, and 4 in sagittal images. The numbers of grades were age-matched in the studied children. The pneumatized sphenoid sinus was identifiable as early as 2 months of age on axial image, and 4 months on sagittal image. Pneumatized sphenoid sinuses were identified in 100% of the subjects studied at the age of 3 years on axial image, and 6 years on sagittal image. All the children over 9 years old showed pneumatization of grade 2 or more both on axial and sagittal images. The results of this study may indicate that the sphenoid sinus begins and completes pneumatization earlier than previously described.     

Incidental petrous apex findings on magnetic resonance imaging

We performed a retrospective chart review to categorize a group of petrous apex findings that were noted incidentally on magnetic resonance imaging (MRI) in 88 patients. These patients were among those who had been seen at a tertiary care center between July 1988 and July 1998. These incidental findings, which were unrelated to the presenting clinical manifestations, included asymmetric fatty bone marrow (n = 41), inflammation (19), cholesterol granulomas (14), cholesteatomas (9), and neoplasms (5). Followup imaging and clinical surveillance of these patients has not demonstrated any significant change in the incidentally detected lesions. In all cases, the incidental MRI findings represented benign pathology.     

Incidental findings on magnetic resonance imaging screening for cerebellopontine angle tumours

The otolaryngologist who requests magnetic resonance imaging (MRI) scans to exclude cerebellopontine angle (CPA) tumours may discover incidental pathologies. We retrospectively reviewed the results of 644 consecutive MRI screening scans with the aim of identifying findings other than CPA tumours. Two hundred and eighty-nine (45 per cent) scans featured one or more anomalies or abnormalities, including CPA tumour (23, four per cent), vascular loop (30, five per cent), basilar artery ectasia (13, two per cent), multiple high signal areas (135,21 per cent), brain atrophy (52, eight per cent), sinus findings (56, nine per cent), middle ear/mastoid disease (34, five per cent), and a variety of other findings (39, six per cent) including clinically serious lesions (11, two per cent). The significance and management of these incidental findings is discussed. The majority were not clinically significant but the occasional presence of a serious incidental pathology should be borne in mind. Basilar artery ectasia and multiple high signal areas may be responsible for the symptoms investigated by MRI, and screening for cerebrovascular disease risk factors in such patients may be appropriate.     

High-field magnetic resonance imaging of paranasal sinus inflammatory disease

Magnetic resonance imaging using a 1.5 tesla magnet and a spin echo technique has revealed a remarkably intense signal from abnormal tissue in the human paranasal sinuses. Inflammatory disease in the maxillary, sphenoid, ethmoid, and frontal sinuses has been detected and demonstrated with greater clarity than any other available technique. The pathophysiologic basis for the intense signal has not been defined. These observations do, however, provide an opportunity to discover, clarify, and study paranasal sinus disease. Acute upper respiratory disease, allergic episodes, and the effect of drug treatment based on the MR signal and pathology can now be investigated with this technique. In addition, this may form a basis for assessing the epidemiology of paranasal sinus pathology.     

False-positive magnetic resonance image in the diagnosis of small acoustic neuroma

A patient presented with sudden hearing loss on her first visit to our department. Gadolinium-DTPA-enhanced magnetic resonance imaging (MRI) of the posterior cranial fossa portrayed an intracanalicular tumour image (2-3 mm), and the pure tone average (PTA) and speech discrimination score (SDS) values were 65 dB and 60 per cent, respectively. Surgical intervention to remove the suspected tumour was scheduled by the translabyrinthine approach. Intracanalicular observations by the retrolabyrinthine approach revealed limited oedema on the inferior vestibular nerve with vascular dilation. The tumour image disappeared two years after the operation. Surgical findings and the post-operative course advocate that gadolinium-DTPA-enriched MRI image of an intracanalicular lesion such as arachnoiditis might produce a false-positive result.     

Functional magnetic resonance imaging of auditory cortex in children

Objective: To obtain images of auditory cortex activation in children by using functional magnetic resonance imaging (FMRI). Methods: Seven healthy children (three girls and four boys), ages 6 to 10 years, were studied. Hearing evaluation was performed by puretone audiometry on the day of FMRI study. Brain imaging was performed on a commercial 1.5 T imager using a three-axis local gradient coil. During scanning the children were instructed to lie still and avoid any lip, eye, jaw, or other facial movements. Subjects were asked to listen to a standard text presented in on-off sequences. Functional images of the auditory cortex were acquired with FMRI technique. Functional imaging processing was done using cross-correlation techniques with a coefficient of 0.5 (P < .0001). Results: Functional correlation images of the auditory cortex activation were obtained in six of seven children after image processing. All children showed activation in the superior temporal gyrus, Heschl's gyrus, planum temporale, frontal lobe, and parietal regions. There was no significant difference in the number and percentage of activated pixels on right and left auditory cortices. Conclusions: Functional images of auditory cortex activation were obtained in healthy children following binaural text presentation. Consistent activation was observed in primary and secondary auditory cortices with no hemispheric dominance. FMRI characteristics of the auditory cortex activation in healthy children should be established in order to study those with hearing impairment.     

Nuclear magnetic resonance tomography after fatty tissue obliteration of the frontal sinus]

BACKGROUND: The osteoplastic flap procedure with fat obliteration has been hailed as the gold standard of definitive frontal sinus procedures for chronic inflammatory disease. The value of magnetic resonance imaging (MRI) in postoperative follow-up has not yet been sufficiently examined. METHODS: All postoperative MRI scans performed in patients undergoing surgery between January 1, 1986, and December 31, 1996 were evaluated. The outcome parameters were time-dependent changes in the distribution of fatty or connective tissue and development of necroses or oil cysts, as well as recurrences, inflammatory complications, or mucoceles. RESULTS: Sixty-eight operations were performed in the specified period and a total of 73 postoperative MRI scans from 45 operations were available for evaluation. In 16 cases, between two and five MRI scans were available. The individual time between surgery and the last MRI scan ranged from two weeks to 130 months with an average of 30.1 months. We found four mucoceles 34, 49, 106, and 130 months, respectively. Three of the mucoceles were diagnosed on the first postoperative MRI scan. In the fourth case the mucocele had not been seen on the previous scan. The amount of adipose tissue depictable on the last scan was less than 20% in the majority of cases (58%) and more than 60% in only 18% of cases, although in the latter group the time between surgery and MRI was less than 7 months in half the cases. CONCLUSIONS: MRI is the most valuable diagnostic tool after frontal sinus obliteration using adipose tissue. Despite the good soft tissue differentiation, the method has some limitations with regard to detection of small recurrent mucoceles and differentiation between vital adipose tissue and fat necrosis in the form of oil cysts. In these difficult cases, long-term MRI follow-up is necessary for definitive evaluation. We therefore recommend MRI 1, 2, and 5 years after osteoplastic frontal sinus surgery with obliteration.     

Relationship between neurological asymptomatic vertigo and the vertebrobasilar system as revealed by magnetic resonance angiography

Many patients suffering from vertigo have no neurological symptoms except for a positional nystagmus. Vertigo without any neurological findings has not been thought to be a vertebrobasilar (VB) attack. The purpose of this study is to clarify the relationship between vertigo without any neurological symptoms and the VB system using magnetic resonance angiography (MRA). MRAs of the VB system were examined in 31 patients with positional nystagmus of unknown origin (PNU) and in 14 patients with benign paroxysmal positional vertigo (BPPV) as control. MRA was performed with a 1.5-tesla system using the two-dimensional time-of-flight technique. Abnormalities such as elongation, bending, narrowing or obstruction of the artery were detected in 27 patients of the PNU group and 8 patients of the BPPV group. A significant difference in the abnormalities was noticed between the two groups (p < 0.05; chi(2) test). This result is almost similar to those of previous studies using conventional vertebral angiography and digital subtraction angiography. Thus, MRA is useful in examination of the VB system. Moreover, our study suggested that the positional nystagmus might result from VB ischemia, even if there were no other neurological signs.     

Preoperative magnetic resonance imaging for localization of the origin of maxillary sinus inverted papillomas

Purpose

It is essential to precisely localize the origin of an inverted papilloma within the maxillary sinus by preoperative imaging so that the lesion can be excised as thoroughly as possible. In the present study, we evaluated the use of preoperative magnetic resonance imaging (MRI) for pinpoint localization of the origin of inverted papillomas.

Materials and Methods

The subjects were patients with an inverted papilloma of the maxillary sinus. Given the known histopathological features and pattern of growth of this tumor, we obtained preoperative MRIs in an attempt to localize its origin.

Results

When different interpretation methods were applied to the preoperative MRIs, there was up to an 85.7% correlation with the surgical results for localization of the tumor origin.

Conclusions

We were able to demonstrate a high rate of agreement between diagnostic imaging and the actual surgical findings in identification of the origin of inverted papillomas.     

The magnetic resonance imaging profile of occult intracranial violations as a result of sinus surgery

INTRODUCTION: Intracranial injury is a well-described complication of sinus surgery. Although such complications are typically associated with catastrophic morbidity, the neurological sequelae may be subtle and even unrecognized during the postoperative period. Magnetic resonance imaging (MRI), which can distinguish intracranial hemorrhage and injury, may provide a means for the accurate assessment of atypical presentations of occult intracranial complications. OBJECTIVE: To describe the MRI profile of occult intracranial complications that result from unrecognized skull base violation during sinus surgery. METHOD: Retrospective chart review. RESULTS: Two patients, who had endoscopic sinus surgery performed elsewhere, underwent postoperative MR for further evaluation of headache. The available medical records, as well as the patient's personal reports, suggested that no intraoperative cranial base compromise had occurred. Both MRIs showed abnormal signal intensity in the brain parenchyma adjacent to the floor of the anterior cranial fossa; these findings are consistent with traumatic injury presumably from the surgical procedure. Neither patient developed postoperative cerebrospinal fluid rhinorrhea, and neither patient experienced focal neurological deficits. CONCLUSION: New-onset and/or atypical headache after sinus surgery may be associated with occult intracranial injury. MRI may serve as the diagnostic means for this occult intracranial violation. Significant incongruity may exist between patient symptoms and the objective MR evidence that can suggest serious intracranial injury. MRI signal patterns can provide both temporal and anatomical cues about the specific injury.     

Preliminary outcomes of cholesteatoma screening in children using non-echo-planar diffusion-weighted magnetic resonance imaging

Objective

Diffusion-weighted (DW) MRI imaging is evolving into an alternative to second look surgery in detection of cholesteatoma recurrence. Insights into the DW MRI appearances of postoperative or inflammatory mucosal changes have recently described using non-echo-planar, turbo spin-echo (TSE) DW MRI which reliably distinguishes between postoperative changes and cholesteatoma. We investigated the use of TSE DW MRI in our pediatric population in order to validate a rapid and cost-effective MRI sequence that can be used to screen for cholesteatoma.

Methods

Prospective comparative study with adult and pediatric patients at a tertiary referral centre. Patients in the study underwent TSE DW MRI prior to second look or revision surgery for cholesteatoma. A Siemens 1.5 T scanner was employed, using the HASTE sequence (EPI DW MRI) as well as standard echo-planar DWI, T1 and T2 sequences. The MRI findings were then correlated with the intraoperative findings at surgery 9-15 months after primary surgery, or of revision surgery in the cases that were referred from other centres. Detection and localisation of cholesteatoma on TSE DW MRI were compared with the findings at second surgery, long considered the gold standard for detection of residual or recurrent disease. Scanning time between the TSE sequence and the standard planar DW MR were also compared.

Results

In a cohort of 92 patients, 21 pediatric patients were identified. 15 patients have had their 15 second look or revision procedures and DW MRI prior to their surgery. TSE DW MRI detected cholesteatoma and reliably identified the location of the cholesteatoma in 2 patients whom all had disease confirmed at surgery. The 13 cases with negative preoperative DW MRI for cholesteatoma were all confirmed to be disease free at surgery. Scanning time of the TSE sequence takes 100 s as opposed to 20 min using standard echo-planar DW MRI techniques without the requirement of a contrast agent and without the need for a general anaesthetic for any of the children.

Conclusion

TSE (HASTE) DW MRI is emerging as a cost effective, noninvasive alternative to second look surgery for detection and screening for cholesteatoma in pediatric patients.     

Piriform sinus tracts in children

OBJECTIVES: To describe the various presentations and management of piriform sinus tracts in children and to provide a treatment algorithm. DESIGN: Case series. SETTING: Pediatric otolaryngology service in a tertiary care setting. PATIENTS: Eight pediatric patients diagnosed as having a piriform sinus tract between 1999 and 2005. INTERVENTIONS: Patients were treated with surgical excision, endoscopic cauterization, or observation. MAIN OUTCOME MEASURE: Recurrence of neck infection. RESULTS: Three different modes of presentation were identified. Four patients presented primarily with an intrathyroidal abscess; 2 presented with recurrent deep neck infections requiring repeated drainage; and 2 presented with symptoms unrelated to the tract. Barium swallows identified the tracts in 5 of 8 patients, and telescopic hypopharyngoscopy identified the tracts in all 8 patients. Five patients were treated with complete excision of their tracts; 1 was treated with cauterization of the internal opening; and 2 were observed for symptoms related to the tracts. All 8 patients are currently asymptomatic. CONCLUSIONS: Piriform sinus tracts are rare. Most patients with tracts present with recurrent deep neck infections. Telescopic hypopharyngoscopy is the diagnostic modality of choice. Endoscopic cauterization is recommended as the initial therapy in symptomatic patients, with complete excision reserved for recurrences. Observation is appropriate for asymptomatic patients.     

Frontal sinus fractures in children

OBJECTIVE: To review the epidemiologic characteristics, clinical course, and management of pediatric patients with frontal sinus fractures. METHODS: Retrospective review of 120 patients with maxillofacial fractures who presented to a tertiary children's hospital from 1998 to 2003 revealed 11 patients with frontal sinus fractures. RESULTS: The study group included 9 males and 2 females with a mean age of 9.7 (range 4-14) years. The most common mechanisms of injury were unrestrained motor vehicle accident and all-terrain vehicle accident. All patients suffered concomitant orbital fractures. Other maxillofacial fractures included sphenoid (4), naso-orbitoethmoid (3), midface (2), and mandible (1). Seven (63.6%) patients sustained significant intracranial injuries including intraparenchymal hemorrhage, expanding pneumocephalus, and subdural hematoma. The average age of patients with intracranial injury was younger than those without intracranial injury (8.1 vs. 12.8 years, P = .025). Four patients had a total of six sites of cerebrospinal fluid (CSF) leak. The most common sites of dural injury were the cribriform area (4) and frontal region (2). All patients with CSF leaks had significant intracranial injuries and required bifrontal craniotomy. CONCLUSIONS: Pediatric frontal sinus fractures are likely to involve other maxillofacial injuries, particularly involving the orbit. Frontal sinus fractures in children are associated with increased risk of serious intracranial injury and CSF leak when compared with adults. The most common site of dural injury was the cribriform area. A multidisciplinary approach is necessary to manage concomitant injuries, obtain separation of the sinonasal tract from intracranial contents, and to restore cosmesis to the brow.