Magnetic resonance assessment of age-related development of the sphenoid sinus

Imaging findings of arrested pneumatisation and differentiation from other skull base lesions

OBJECTIVES

Arrested pneumatisation (AP) is an anatomic variant of the sphenoid sinus. Since AP remains underrecognised, otolaryngologists and radiologists may mistake AP for a lesion and perform follow-up imaging studies. We investigated the imaging findings of CT, MRI, and F-18 fludeoxyglucose (FDG)-positron emission tomography (PET) for AP, and discussed the differences between AP and other skull base lesions.

METHODS

We reviewed multidetector low CT imaging of 442 patients (285 men and 157 women; age range, 19-93 years; mean age, 67.8 years) who underwent FDG-PET/CT for head and neck tumours between January 2019 and December 2019. The imaging findings of AP were reviewed on CT, MRI, FDG-PET/CT, and compared with those of fibrous dysplasia, chordoma, chondrosarcoma, multiple myeloma, and bone invasion of nasopharyngeal carcinoma.

RESULTS

AP was identified in 22 patients (14 men and 8 women; age range, 24-93 years; mean age, 67.0 years) based on criteria from previous reports. AP manifested with well-circumscribed sclerotic margins on CT, without evidence of expansion. AP showed high-signal intensity on T1-/T2 weighted MRI. FDG-PET revealed non-significant uptake [maximum standardised uptake value (SUVmax): 0.85 (range, 0.4-1.27)] in AP. Contrastingly, skull base lesions showed expansion, poorly circumscribed boundaries without osteosclerotic margins, and moderate-to-severe FDG uptake (SUVmax: 1.8-8.4).

CONCLUSIONS

The characteristic imaging findings of AP, namely non-expansile on CT and non-uptake on FDG-PET, may aid in its differentiation from other skull base lesions.

Critical review of diagnosis in rhinology and its therapeutical implications

Diagnosis in rhinology is currently based on the concept of inflammation (chronic rhinosinusitis [CRS]) or the clinical concept of chronic nasal dysfunction (CND). The complementarity between these two approaches can be discussed by a critical review of the literature structured by the analysis of the fundamental and diagnostic bases and the therapeutic implications linked to each. The concept of CRS is based on the anatomical continuity of the nasal and sinus respiratory mucosa and molecular biology data, seeking to analyze the mechanisms of chronic inflammation and to identify proteins and biomarkers involved in the different supposed endotypes of chronic inflammation of this mucosa. The concept of CND seeks to analyze medical, instrumental or surgical diagnostic and therapeutic strategies, taking account of both inflammatory and non-inflammatory causes impacting the anatomy or physiology of each of the three noses (olfactory, respiratory and sinus) that make up the mid-face sinonasal organ of evolution-development (Evo-Devo) theory. Thus, the concept of CRS offers an endotypic approach, based on biological characterization of mucosal inflammation, while the concept of CND offers a compartmentalized phenotypic and pathophysiological approach to sinonasal diseases. The joint contribution of these two concepts in characterizing nasal functional pathology could in future improve the medical service provided to patients.

Development of the sphenoid sinus from newborn to age 18: A computed tomography imaging analysis

OBJECTIVES

The sphenoid sinus (SS) is an important anatomical formation in terms of its location and relationship with important neurovascular structures. It is essential to evaluate the pneumatization and dimensions of the SS with Computed Tomography (CT) in the preoperative period of transsphenoidal interventions to be performed on tumors located in this region. The aim of this study was to evaluate the correlation of the volume and dimensions of the SS measured with CT with age in the period from birth to 18 years of age.

METHODS

In this retrospective study, a total of 360 brain, paranasal sinus, temporal bone and maxillofacial CT scans of individuals from birth to 18 years of age were evaluated. The cohort was divided into 18 groups with 20 (10 female, 10 male) patients in each age group. The height, width, length and volume values of the SS were measured on CT and their correlations with age and the differences between genders were evaluated statistically.

RESULTS

It has been determined that the increases in the size and volume of the SS accelerate especially between 1 and 2 years of age and begins to reach adult dimensions after 12 years of age. Height and length of the sphenoid sinus showed a high correlation coefficient (r = 0.717 and r = 0.731 respectively) with age, while its width and volume showed a moderate correlation coefficient (r = 0.662 and 0.543 respectively). There was no statistically significant difference between the genders in terms of SS height, width, length and volume.

CONCLUSIONS

SS dimensions and volume showed a logaritmic growth pattern from birth to 18 years. The results of this study may help to better understand the normal development of SS in children and may serve as a reference for more comprehensive CT studies. In addition, it can help surgeons to evaluate the developmental characteristics of SS in surgical interventions for SS in children.

Arrested Pneumatization of the Sphenoid Sinus

The sphenoid bone is a complex structure in terms of its embryological origin. At birth, the sphenoid sinus is nonpneumatized. Arrested pneumatization of the sphenoid sinus is considered a normal anatomic variant but may be mistaken for disease in imaging studies. We report 2 cases of arrested pneumatization of the sphenoid sinus, a normal variant commonly misdiagnosed as a serious disease of the skull base. A 29-year-old man with a complaint of dizziness visited a local clinic for assessment. Computed tomography (CT) of the paranasal sinuses (PNS) showed a noneroding, nonexpansile, and nonhomogenous lesion in the sphenoid bone. Magnetic resonance imaging (MRI) of the brain revealed a high-signal lesion on both T1-weighted and T2-weighted images. Given these typical findings in the CT of PNS and MRI of the brain, the lesion was diagnosed as arrested pneumatization of the sphenoid sinus. In the second case, a 60-year-old woman with a complaint of headache visited a local clinic for assessment. CT of PNS showed a fibro-osseous lesion (with features of sclerosis and osteolysis) in the skull base. Brain MRI revealed a low-signal lesion on a T1-weighted image containing a high-signal intensity around the sphenoid bone, thereby suggesting internal fat contents. A precise interpretation of CT of PNS and brain MRI is essential to distinguish arrested pneumatization of the sphenoid sinus and to help establish a differential diagnosis and avoid needless biopsy.

A practical overview of CT and MRI features of developmental, inflammatory, and neoplastic lesions of the sphenoid body and clivus

The sphenoid bone is an unpaired bone that contributes to the formation of the skull base. Despite the enormous progress in transnasal endoscopic visualisation, imaging techniques remain the cornerstones to characterise any pathological condition arising in this area. In the present review, we offer a bird’s-eye view of the developmental, inflammatory, and neoplastic alterations affecting the sphenoid body and clivus, with the aim to propose a practical diagnostic aid for radiologists based on clinico-epidemiological, computed tomography, and magnetic resonance imaging features.

Sphenoid Bone Pneumatisation on Lateral Cephalograms of Patients With Neurofibromatosis Type 1

BACKGROUND/AIM

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disease that causes tumors and many developmental disorders, e.g., cranial dysplasia. The purpose of this retrospective study was to analyse the pneumatisation of the sphenoid bone in NF1.

PATIENTS AND METHODS

The anonymised lateral cephalograms of 166 NF1 patients and 166 age- and sex-matched controls were examined for anterior-posterior sphenoid pneumatisation. The patient group analysis considered whether the patients had been affected by a facial plexiform neurofibroma (FPNF).

RESULTS

Sphenoid pneumatisation was significantly lower in NF1 patients than in controls [odds ratio (OR)=0.184; 95%CI=0.11-0.32; p<0.001]. A FPNF statistically significantly reduced sinus formation in patients (OR=0.38; p=0.002).

CONCLUSION

The condition 'NF1' has an effect on sphenoid pneumatisation. The findings are relevant for planning surgical procedures in this region and confirm current concepts to evaluate NF1 as a histogenesis control gene. The examination technique and basis of calculation presented here are easy-to-use and low-irradiation exposure instruments for screening for differences in sphenoid bone pneumatisation in defined populations.

Magnetic Resonance Imaging Detects Chronic Rhinosinusitis in Infants and Preschool Children with Cystic Fibrosis

Rationale: Chronic rhinosinusitis (CRS) contributes to disease burden of patients with cystic fibrosis (CF). However, its onset and progression in infants and preschool children with CF remain poorly understood.Objectives: To determine the prevalence and extent of CRS in young children with CF using magnetic resonance imaging (MRI).Methods: MRI was performed in sedation in 67 infants and preschool children with CF (mean age 2.3 ± 2.1 yr; range 0-6 yr) and 30 non-CF control subjects (3.5 ± 2.0 yr; range 0-6 yr). Paranasal sinus dimensions and structural abnormalities, including mucosal swelling; mucopyoceles; and nasal polyps of the maxillary, frontal, sphenoid, and ethmoid sinuses; and, in addition, medial maxillary sinus wall deformation, were assessed using a dedicated CRS MRI scoring system.Results: Pneumatization and dimensions of paranasal sinuses did not differ between the two groups. MRI detected an increased prevalence of mucosal swelling (83% vs. 17%; P < 0.001), mucopyoceles (75% vs. 2%; P < 0.001), polyps (26% vs. 7%; P < 0.001), and maxillary sinus wall deformation (68% vs. 2%; P < 0.001) in infants and preschool children with CF compared with age-matched control subjects. Furthermore, the extent of these abnormalities was also increased with a MRI sum score of 22.9 ± 10.9 in CF compared with 4.5 ± 7.6 in non-CF control subjects (P < 0.001).Conclusions: MRI detected normal dimensions of paranasal sinuses, and a high prevalence and severity of paranasal sinus abnormalities due to CRS in infants and preschool children with CF without radiation exposure. Our results support the development of MRI for sensitive noninvasive diagnosis and monitoring of CRS in young children with CF, and as outcome measures for clinical trials.Clinical trial registered with www.clinicaltrials.gov (NCT00760071).

Imaging of Paranasal Sinus Infections in Children: A Review

Paranasal sinuses (PNS) infections are common in children. They may cause common and well-known complications, but also, unusual and potentially devastating complications. Diagnosing PNS infections and complications in children requires knowledge of the unique anatomy of the nasal cavity and the PNS. In fetal life, nasal mucosa evaginations into the lateral nasal walls initiate the development of the PNS. The PNS continue to develop after birth and complete their maturation and pneumatization at different ages during childhood which makes the pattern of PNS infections determined by patient age. Complications are caused by direct spread of the infection to the orbit, face, intracranial or osseous structures or hematogenous spread of the infection to the intracranial structures. Emergent imaging studies are often necessary in the evaluation of the complications in pediatric patients when the symptoms persist for 10 days and/or if there is evidence of intracranial or orbital complications. In addition, immunocompromised children are especially vulnerable to developing unusual complications. Computed tomography (CT) is excellent for determining whether there is intraorbital extension of PNS disease. However, when the infection approaches the orbital apex, a magnetic resonance imaging (MRI) study with contrast is necessary to assess spread into the cavernous sinus and the intracranial compartment. The goal of this manuscript is to review and characterize imaging findings of PNS infections using CT and MRI allowing determination of the extent of PNS infections and their common and unusual complications in children. In addition, a summary of the development of the normal PNS is provided.

A rare case of odontogenic keratocyst extending into the sphenoid bone from the maxilla

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Odontogenic keratocyst (OKC) is the third most common odontogenic cyst which arises from cell rests of dental lamina.

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Because of high rate of recurrence, there are various treatment strategies.

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OKC is usually observed in the jaws.

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We report on a rare case of OKC which involved the maxillary sinus extending into the sphenoid bone nearly to the skull base.

Background

Odontogenic keratocyst (OKC) is the third most common odontogenic cyst which arises from cell rests of dental lamina, and usually observed in the jaws. Because OKC is noted for its high rate of recurrence, there are various treatment strategies. Here, we present a rare case of OKC which occupied the entire maxillary sinus and pterygoid process of the sphenoid bone extending nearly to the skull base.

Case presentation

The patient was a 21-year-old male and underwent surgical removal of the cyst using the Caldwell-Luc procedure which in this case extended the surgical approach to the pterygoid process of the sphenoid bone via the pterygomaxillary junction. However, we found a recurrent lesion in the posterior wall of the maxillary sinus 20 months after the surgery and subsequently performed a secondary cystectomy. Surgical specimens showed positive bcl-2 staining of OKC and negative cytokeratin-10 on immunohistochemistry for both primary and recurrent lesions.

Conclusion

OKC rarely occurs in the maxillary sinus and extends to the deep maxillary structure and the skull base. In order to prevent recurrence, it is necessary to recognize the exact location of the entire lesion. Careful examination of preoperative CT images is needed to make a complete surgical planning and to perform a reliable surgical procedure.

Pediatric pituitary adenomas

BACKGROUND

Pediatric pituitary adenomas are a rare medical entity that makes up a small portion of intracranial tumors in children and adolescents. Although benign, the majority of these lesions are secreting functional tumors with the potential for physiological sequela that can profoundly affect a child's development.

FOCUS OF REVIEW

In this review, we discuss the medical and surgical management of these tumors with a focus on clinical presentation, diagnostic identification, surgical approach, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to treat these tumors. The management of pituitary tumors requires a multidisciplinary team of surgeons, endocrinologists, and neuroanesthesiologists as well as neurocritical care specialists to deliver comprehensive care.

Anatomical variation of the sphenoid sinus in paediatric patients and its association with age and chronic rhinosinusitis

OBJECTIVE

To report the prevalence of different anatomical variations of the sphenoid sinus and its related structures among paediatric patients with or without chronic rhinosinusitis.

METHODS

Computed tomography scans of 50 paediatric patients with chronic rhinosinusitis were reviewed and compared to 50 scans of paediatric patients without chronic rhinosinusitis. The type of sphenoid sinus pneumatisation and the surrounding structures were thoroughly analysed. The patients were divided into three groups according to age.

RESULTS

Mean age was 10.9 years (range, 4-16 years). The sellar configuration was the commonest in all groups, while the conchal type was the least common. There were significant differences between paediatric patients with or without sinusitis in: sphenoid sinus pneumatisation type, vidian canal type and Onodi cell presence. In addition, there were significant differences between age groups in: sphenoid sinus pneumatisation type, single sinus septum and multiple septa presence, and internal carotid artery bulging.

CONCLUSION

Age and sinusitis have a significant impact on sphenoid pneumatisation type and surrounding structure variation. Recognition of these variations can be useful for mapping this region, and enables a safer and more efficient endoscopic surgical procedure.

Pediatric Craniopharyngiomas: A Primer for the Skull Base Surgeon

Pediatric craniopharyngioma is a rare sellar-region epithelial tumor that, in spite of its typically benign pathology, has the potential to be clinically devastating, and presents a host of formidable management challenges for the skull base surgeon. Strategies in craniopharyngioma care have been the cause of considerable controversy, with respect to both philosophical and technical issues. Key questions remain unresolved, and include optimizing extent-of-resection goals; the ideal radiation modality and its role as an alternative, adjuvant, or salvage treatment; appropriate indications for expanded endoscopic endonasal surgery as an alternative to transcranial microsurgery; risks and benefits of skull base techniques in a pediatric population; benefits of and indications for intracavitary therapies; and the preferred management of common treatment complications. Correspondingly, we sought to review the preceding basic science and clinical outcomes literature on pediatric craniopharyngioma, so as to synthesize overarching recommendations, highlight major points of evidence and their conflicts, and assemble a general algorithm for skull base surgeons to use in tailoring treatment plans to the individual patient, tumor, and clinical course. In general terms, we concluded that safe, maximal, hypothalamic-sparing resection provides very good tumor control while minimizing severe deficits. Endoscopic endonasal, intraventricular, and transcranial skull base technique all have clear roles in the armamentarium, alongside standard craniotomies; these roles frequently overlap, and may be further optimized by using the approaches in adaptive combinations. Where aggressive subtotal resection is achieved, patients should be closely followed, with radiation initiated at the time of progression or recurrence-ideally via proton beam therapy, although three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and stereotactic radiosurgery are very appropriate in a range of circumstances, governed by access, patient age, disease architecture, and character of the recurrence. Perhaps most importantly, outcomes appear to be optimized by consolidated, multidisciplinary care. As such, we recommend treatment in highly experienced centers wherever possible, and emphasize the importance of longitudinal follow-up-particularly given the high incidence of recurrences and complications in a benign disease that effects a young patient population at risk of severe morbidity from hypothalamic or pituitary injury in childhood.

Pediatric Pituitary Adenoma: Case Series, Review of the Literature, and a Skull Base Treatment Paradigm

Background  Pediatric pituitary adenoma is a rare skull base neoplasm, accounting for 3% of all intracranial neoplasms in children and 5% of pituitary adenomas. Compared with pituitary tumors in adults, secreting tumors predominate and longer disease trajectories are expected due to the patient age resulting in a natural history and treatment paradigm that is complex and controversial. Objectives  The aims of this study were to describe a large, single-institution series of pediatric pituitary adenomas with extensive long-term follow-up and to conduct a systematic review examining outcomes after pituitary adenoma surgery in the pediatric population. Methods  The study cohort was compiled by searching institutional pathology and operative reports using diagnosis and site codes for pituitary and sellar pathology, from 1956 to 2016. Systematic review of the English language literature since 1970 was conducted using PubMed, MEDLINE, Embase, and Google Scholar. Results  Thirty-nine surgically managed pediatric pituitary adenomas were identified, including 15 prolactinomas, 14 corticotrophs, 7 somatotrophs, and 4 non-secreting adenomas. All patients underwent transsphenoidal resection (TSR) as the initial surgical treatment. Surgical cure was achieved in 18 (46%); 21 experienced recurrent/persistent disease, with secondary treatments including repeat surgery in 10, radiation in 14, adjuvant pharmacotherapy in 11, and bilateral adrenalectomy in 3. At the last follow-up (median 87 months, range 3-581), nine remained with recurrent/persistent disease (23%). Thirty-seven publications reporting surgical series of pediatric pituitary adenomas were included, containing 1,284 patients. Adrenocorticotropic hormone (ACTH)-secreting tumors were most prevalent (43%), followed by prolactin (PRL)-secreting (37%), growth hormone (GH)-secreting (12%), and nonsecreting (7%). Surgical cure was reported in 65%. Complications included pituitary insufficiency (23%), permanent visual dysfunction (6%), chronic diabetes insipidus (DI) (3%), and postoperative cerebrospinal fluid (CSF) leak (4%). Mean follow-up was 63 months (range 0-240), with recurrent/persistent disease reported in 18% at the time of last follow-up. Conclusion  Pediatric pituitary adenomas are diverse and challenging tumors with complexities far beyond those encountered in the management of routine adult pituitary disease, including nuanced decision-making, a technically demanding operative environment, high propensity for recurrence, and the potentially serious consequences of hypopituitarism with respect to fertility and growth potential in a pediatric population. Optimal treatment requires a high degree of individualization, and patients are most likely to benefit from consolidated, multidisciplinary care in highly experienced centers.

Enhancing Mass Lesion of the Sphenoid: Atypical Presentation of Ongoing Pneumatization

Sinus pneumatization is a complex variable process that begins in early life and continues for many years. We present a case of a 6-year-old boy with progressive headaches and neurologic symptoms suggestive of intracranial pathology. The presence of enhancing tissue within the sphenoid sinus created a diagnostic dilemma which leads to a transsphenoidal biopsy. Knowledge of imaging characteristics associated with incomplete pneumatization can help differentiate it from more ominous skull base pathology and prevent unnecessary testing. We describe four-year imaging follow-up in a patient with incomplete pneumatization of the sphenoid sinus presenting as an enhancing mass lesion with subsequent follow-up imaging demonstrating gradual regression and increased aeration of the sphenoid sinus.

The CT Prevalence of Arrested Pneumatization of the Sphenoid Sinus in Patients with Sickle Cell Disease

BACKGROUND AND PURPOSE

Arrested sphenoid pneumatization is an incidental radiologic finding on CT and MR imaging that may be confused with more aggressive pathologic conditions. No definite etiology for arrested sphenoid pneumatization has been established, though changes in regional blood flow during childhood, as is seen with sickle cell disease, have been proposed. The purpose of our study was to compare the prevalence of arrested pneumatization of the sphenoid sinus in patients with and without sickle cell disease.

MATERIALS AND METHODS

We retrospectively identified 146 patients with sickle cell disease who had undergone CT scans of the skull base between January 1990 and May 2015. We identified 292 control patients without sickle cell disease matched for age and sex in a 1:2 ratio. We tabulated the prevalence of arrested pneumatization as well as the location and size of the lesions. We used the Fisher exact test to correlate sickle cell disease with arrested pneumatization of the sphenoid sinus and the t test to correlate sickle cell disease with lesion size.

RESULTS

Of the 146 patients with sickle cell disease, 14 (9.6%) had arrested pneumatization of the sphenoid sinus. In the 292 control patients, 6 (2.1%) had arrested pneumatization. Patients with sickle cell disease had a statistically significant higher rate of arrested pneumatization compared with patients without sickle cell disease (P < .001). There was no statistically significant correlation between lesion size and diagnosis of sickle cell disease.

CONCLUSIONS

Patients with sickle cell disease have a greater prevalence of arrested pneumatization of the sphenoid sinus than patients without sickle cell disease. This supports the theory that either regional blood flow anomalies or increased serum erythropoietin causes arrested sinus pneumatization.

Arrested pneumatization of the sphenoid sinus mimicking intraosseous lesions of the skull base

Arrested pneumatization of the sphenoid sinus is a developmental variant that is not always well recognized and is often confused with other pathologies associated with the skull base. This report describes the case of a patient referred for cone-beam computed tomography (CBCT) imaging for dental implant therapy. CBCT demonstrated a well-defined incidental lesion in the left sphenoid sinus with soft tissue-like density and sclerotic borders with internal curvilinear opacifications. The differential diagnoses included intraosseous lipoma, arrested pneumatization of the sphenoid sinus, chondrosarcoma, chondroid chordoma, and ossifying fibroma. The radiographic diagnosis of arrested pneumatization was based on the location of the lesion, its well-defined nature, the presence of internal opacifications, and lack of expansion. Gray-scale CBCT imaging of the area demonstrated values similar to fatty tissue. This case highlighted the fact that benign developmental variants associated with the skull base share similar radiographic features with more serious pathological entities.

Arrested pneumatization: witness of paranasal sinuses development?

OBJECTIVES

Recent radiological studies have demonstrated that formation of the sphenoid sinus is preceded by a phase of fatty transformation of the bone marrow, and then by a phase of fat involution prior to the appearance of an aerated cavity and that this process can sometimes be interrupted, resulting in the persistence of images of arrested pneumatisation. The objective of the study was to confirm the existence of arrested pneumatisation in the sphenoid bone, and to investigate the presence of similar images in the maxilla, frontal and ethmoid bones.

MATERIAL AND METHODS

In this single-centre, retrospective study, 207 CT scans with no signs of mucosal opacity or sinus retention performed for assessment of septorhinoplasty or chronic nasal dysfunction were reviewed according to Welker's criteria to detect images of arrested pneumatisation.

RESULTS

Twenty-two patients presented 30 images suggestive of arrested pneumatisation of the maxilla (13/30), sphenoid (10/30) and frontal (7/30) bones. No images of arrested pneumatisation were observed in the ethmoid bone.

CONCLUSIONS

The results of this study question the classical mechanisms of formation of the paranasal sinuses. According to the hypothesis of postnatal bone cavitation resulting from bone marrow involution and centripetal gas production, paranasal sinuses would constitute distinct organs that develop independently of the ethmoidal olfactory organ, which is formed from the embryonic cartilaginous olfactory capsule.

Impact of skull base development on endonasal endoscopic surgical corridors

OBJECT

Scarce morphometric data exist on the developing skull base as a corridor for endonasal endoscopic approaches (EEAs). Furthermore, the impact of skull base lesions on its development has not been assessed. The authors describe a novel set of anatomical parameters characterizing the developmental process as well as the utility of these parameters in preoperative planning and a feasibility assessment of EEAs for neurosurgical treatment of skull base lesions in children.

METHODS

Based on specific MRI sequences in 107 pediatric patients (2-16 years of age) without skull base lesions (referred to here as the normal population), 3 sets of anatomical parameters were analyzed according to age group and sex: drilling distance, restriction sites, and working distance parameters. A separate set of patients undergoing EEAs was analyzed in similar fashion to address the impact of skull base lesions on the developmental process.

RESULTS

The volume of the sphenoid sinus significantly increases with age, reaching 6866.4 mm(3) in the 14-16 years age group, and directly correlates with the pneumatization type (r = 0.533, p = 0.0001). The pneumatization process progresses slowly in a temporal-posterior direction, as demonstrated by the growth trend of the sellar width (r = 0.428, p = 0.0001). Nasal restriction sites do not change significantly with age, with little impact on EEAs. The intercarotid distance is significantly different only in the extreme age groups (3.9 mm, p = 0.038), and has an important impact on the transsphenoidal angle and the intracranial dissection limits (r = 0.443, p < 0.0001). The 14.9° transsphenoidal angle at 2-4 years has a 37.6% significant increase in the 11-13 years age group (p = 0.001) and is highly dependent on pneumatization type. Age-dependent differences between working parameters are mostly noted for the extreme age groups, such as the 8.6-mm increase in nare-vomer distance (p = 0.025). The nare-sellar distance is the only parameter with significant differences based on sex. Skull base lesions induce a high degree of variance in skull base measurements, delaying development and decreasing parameter values. Skull base parameters are interdependent. Nare-sellar distance can be used to assess global skull base development because it highly correlates with the intercarotid distance in both the normal population and in patients harboring skull base lesions.

CONCLUSIONS

Skull base development is a slow, gradual, age-dependent, sex-independent process significantly altering endonasal endoscopic corridors. Preoperative MRI measurements of the pediatric skull base are thus a useful adjunct in choosing the appropriate corridor and in assessing working angles and limits during dissection or reparative surgery. Skull base lesions can significantly impact normal skull base development and age-dependent growth patterns.

Paranasal sinus development in children: A magnetic resonance imaging analysis

BACKGROUND

The anatomy of the paranasal sinus is significantly different between adults and children, and surgeons must be aware of these differences to safely perform pediatric functional endoscopic sinus surgery. The purpose of this study was to determine the normal dimensions of the paranasal sinuses during development using magnetic resonance imaging (MRI) data compiled from the largest cohort to date.

METHODS

The records of 2025 children, aged 0-18 years, who underwent cranial MRI, were examined retrospectively and 1452 patients with no history of sinus disease were included in the study. Coronal, axial, and sagittal images were used to measure the dimensions of the frontal, maxillary, ethmoid, and sphenoid sinuses, and the sinus volume index was measured. Patients were divided into 10 cohorts based on their age at the time of the scan.

RESULTS

No difference between left and right one-dimensional measurements and volume indexes for the maxillary, sphenoid, ethmoid, and frontal sinuses was observed in any age group. Initial signs of pneumatization were observed at birth for the maxillary and ethmoid sinuses, at 9 months for sphenoid sinus, and after the age of 5 years for the frontal sinus.

CONCLUSION

These results will help physicians correlate the clinical and radiographic findings of pediatric patients who are being evaluated for sinus disease and potential surgical intervention. Knowledge of the variations in the size of the paranasal sinuses is essential for determining the significance of incidental findings.

Arrested pneumatization of the skull base: imaging characteristics

OBJECTIVE

Arrested skull base pneumatization is a benign developmental variant that can be confused with significant skull base disease processes. This study reviews the imaging findings in 30 suspected cases of arrested skull base pneumatization.

CONCLUSION

When encountering a nonexpansile lesion with osteosclerotic borders, internal fat, and curvilinear calcifications in the basisphenoid bone or adjacent skull base, radiologists should strongly consider the diagnosis of arrested pneumatization.

Radiological imaging of inflammatory lesions in the nasal cavity and paranasal sinuses

Paranasal sinus development and pneumatisation variants are described, and rhinosinusitis and different patterns of inflammatory sinonasal diseases are reviewed. Other inflammatory sinonasal diseases, e.g., fungal sinusitis, mucocele, pyocele and sinonasal manifestations in systemic diseases, are briefly described. Computed tomography (CT) is the primary modality in diagnosing and mapping suspected inflammatory sinonasal disease. Magnetic resonance (MR) imaging is complementary to CT if fungal sinusitis, pyocele or malignancy are suspected.

Pneumatization of turbinates

OBJECTIVES

To present unusual computed tomography (CT) findings concerning huge pneumatization of turbinates and paranasal sinuses in one patient. In current world literature the authors only found nine reports of pneumatization of inferior turbinates, which, therefore, must be considered an extremely rare anatomical finding.

STUDY DESIGN

Case report and literature review.

METHODS

Computed tomography findings in a 35-year-old white woman with nasal obstruction are presented; and the authors describe this additional case of pneumatization of an inferior turbinate, as well as other variants. The literature and nomenclature are reviewed.

RESULTS

Besides the rare anatomical finding of a pneumatized inferior turbinate, in addition, both patient middle and superior turbinates were pneumatized bilaterally. Frontal and sphenoid sinuses were huge, with pneumatization of the crista galli and the posterior parts of the septum. The floor of the orbit presented with an orbitoethmoid (Haller) cell on one side. Thus, five of the six turbinates present were pneumatized. To the authors' knowledge, no other case of such extreme pneumatization has been published in world literature to date.

CONCLUSIONS

Whereas pneumatization of the ethmoturbinals is a frequent finding on sinus computed tomography scans, pneumatization of the maxilloturbinal remains an extremely rare anatomical variant. Pneumatization of ethmoid cells and secondary sinuses is considered an active achievement of nasal and sinus mucosa during fetal development and adolescence. The underlying mechanisms of this process are not yet understood. The inferior turbinate is the least likely to present with pneumatization. In clinical practice, the pneumatization status should well be studied on the scans before any sinus and turbinate surgery is undertaken.

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.

Hyperaeration of the sphenoid sinus: cause for concern?

A case of exuberant pneumatization of the left sphenoid sinus into the pterygoid process and floor of the middle cranial fossa is presented. The fact that pneumatization of the sphenoid sinus is frequently atypical is of clinical import because there is an intimate relationship between the contents of a hyperaerated sinus and adjacent vital facial and cranial structures. It is imperative that clinicians determine the location and extent of the walls of the sphenoid sinus and its relationship to adjacent vital structures whenever endoscopic sinus surgery is contemplated to avoid morbid consequences during surgery.