Variations of sphenoid and related structures

The aim of this study was to delineate the precise relationship between the sphenoid sinus and internal carotid artery and the optic nerve, as well as to assess incidence of the anatomic variations of these structures. A review of 92 paranasal sinus tomographic scans was made for anatomic variations of the sphenoid sinus and related bony and neurovascular structures. Coronal and axial tomographic sections were obtained with 2.5-mm section thickness. We assessed the protrusion of the internal carotid artery (ICA) and the optic nerve (ON) into the sphenoid sinus, bone dehiscence of these structures, and pneumatization of the anterior clinoid process (ACP) and pterygoid recess (PR), as well as the variations of the sphenoid sinus septum. The protrusion of the ICA into the sphenoid sinus was found in 24 (26.1 %) patients. An ON protrusion was present in 29 (31.5 %) patients. Pneumatization of the PR was encountered in 27 (29.3 %) patients. There was not a statistically significant relationship between the pneumatization of the PR and ICA protrusion into the sphenoid sinus (χ ² = 0.258, p = 0.168). A significant relationship between the ACP pneumatization and protrusion of the ON into the sphenoid sinus was found (χ ² = 0.481, p = 0.007). Preoperative recognition of the anatomic variations by the radiologist is beneficial for identification of the limits of dissection. This is particularly important in the sphenoid sinus area where extensive pneumatization of the skull base bones may distort the anatomic configuration. Therefore, axial and coronal CT sections should always be obtained prior to any surgery in the sphenoid sinus area. Received: 27 January 1999; Revised: 12 August 1999; Accepted: 1 September 1999     

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.

The normal development of the sphenoid sinus is preceded by a phase of fatty transformation and fat involution in the bone marrow, followed by aeration of the marrow that then results in full pneumatization.^1,2 This process begins at 4 months of age and usually ends at 10–14 years of age.^3,4 This process may be interrupted, leaving atypical fatty marrow that persists into adulthood.Change in regional blood flow has been suggested as a potential stimulus for fatty marrow conversion.⁵ If this theory is correct, then diseases that produce aberrant regional blood flow might predispose a person to arrested sinus pneumatization. Sickle cell disease (SCD) is an example of a disorder that produces regional blood flow changes in childhood, but no study has investigated the correlation between arrested sphenoid pneumatization and SCD.We hypothesized that there is an increased prevalence of arrested pneumatization of the sphenoid sinus in patients with SCD compared with those without SCD.     

Remarkable anatomic variations in paranasal sinus region and their clinical importance

With the advent of functional endoscopic sinus surgery (FESS) and coronal computed tomography (CT) imaging, considerable attention has been directed toward paranasal region anatomy. Detailed knowledge of anatomic variations in paranasal sinus region is critical for surgeons performing endoscopic sinus surgery as well as for the radiologist involved in the preoperative work-up. To be in the known anatomical variants with some accompanying pathologies, directly influence the success of diagnostic and therapeutic management of paranasal sinus diseases. A review of 512 (1024 sides) paranasal sinus tomographic scans was carried out to expose remarkable anatomic variations of this region. We used only coronal sections, but for some cases to clear exact diagnosis, additional axial CT scan, magnetic resonance imaging (MRI) and nasal endoscopy were also performed. In this pictorial essay, rates of remarkable anatomic variations in paranasal region were displayed. The images of some interesting cases were illustrated, such as the Onodi cell in which isolated mucocele caused loss of visual acuity, agger nasi cell, Haller's cell, uncinate bulla, giant superior concha bullosa, inferior concha bullosa, bilateral carotid artery protrusion into sphenoid sinus, maxillary sinus agenesis, bilateral secondary middle turbinate (SMT) and sphenomaxillary plate. The clinical importance of all these variations were discussed under the light of the literature. It was suggested that remarkable anatomic variations of paranasal region and their possible pathologic consequences should be well defined in order to improve success of management strategies, and to avoid potential complications of endoscopic sinus surgery. The radiologist must pay close attention to anatomical variations in the preoperative evaluation.     

CT characterization of developmental variations of the paranasal sinuses in cystic fibrosis

Purpose: To describe variations of paranasal sinus development in patients with cystic fibrosis (CF) and in non-CF patients examined for inflammatory sinonasal disease. We focused on anatomic variants that predispose to orbital and cerebral penetration during functional endoscopic sinus surgery (FESS), e.g. hypoplasia of the maxillary sinus and low ethmoid roof.Material and Methods: One hundred and sixteen CF patients (3-54 years, median 18) and 136 control patients (7-51 years, median 31) were examined with coronal CT of the paranasal sinuses. CF patients were grouped according to number of confirmed mutations: CF-2 (n=70), CF-1 (n=32), CF-0 (n=14). CT images were evaluated with respect to paranasal sinus development, pneumatization variants and bony variants.Results: Frontal sinus aplasia and maxillary, ethmoid, and sphenoid sinus hypoplasia were markedly more frequent in CF-2 than in control patients. No CF-2 patient had pneumatization variants such as Haller cells or concha bullosa. Low ethmoid roof was seen in 30% of CF-2 children, but in no control children. CF-1 and CF-0 groups had prevalences of aplasia and hypoplasia intermediate to that of CF-2 and control patients.Conclusion: Genetically verified CF patients had less developed sinuses, lacked pneumatization variants, and more often had anatomic variants that predispose to complications during FESS. Normally developed sinuses and pneumatization variants in some genetically unverified CF patients (CF-1, CF-0) suggest that these patients may be erroneously diagnosed.     

Variability in sphenoid sinus pneumatization and its impact upon reduction of complications following sellar region surgeries

BackgroundThe rapid evolution of transsphenoidal endoscopic surgical intervention and surgeries of skull base and sellar regions is accompanied by multiple complications.ObjectiveTo determine different types of extension of sphenoid sinus pneumatization detected by CT and MRI and their impact upon different approaches and complications of sellar region surgeries.Subjects and methodsThe pre-operative CT and MRI images of 182 patients with surgical intervention for peri-sellar region pathologies were retrospectively evaluated for patterns of sphenoid pneumatization. Post surgical complications were recorded and analyzed.ResultsThe overall rate of complications was 88 affecting 62 patients (34%), and 120 patients (66%) were free of complications. Different types of pneumatization were detected on CT and MRI images, conchal in 3 cases (1.6%), presellar 23 cases (12.6%) and 156 cases (85.7%) showing sellar pneumatization. Sellar pattern was reclassified into 6 types. Single inter sphenoid septum was seen in 109 patients, accessory septum was found in 13 patients and 10 patients have multiple sphenoid septation. 24 patients (13.2%) show absent septum.ConclusionPre-intervention assessment of sphenoid sinus pneumatization is mandatory in approaching the sella and skull base structures either via the nose or open skull base surgery to avoid injury of the nearby structures and reduce the possibility of CSF leakage.     

X-ray computed tomographic study of the ethmoid and middle meatus. II. Radio-anatomy (axial incidence) and morphological variations

Chronic rhinosinusitis endoscopic surgery needs an accurate evaluation of diseases and paranasal sinus anatomic variations. High resolution CT by thin section (2 mm) allow this pre-operative assessment. An anatomical study of the ethmoid air cell system is always possible in axial plane. The bidimensional CT exploration (axial and coronal plane) displays the anatomic variations of ostiomeatal unit, that have been reported to predispose sinusitis. They are nasal septal deviation, pneumatization and paradoxical curvature of the middle turbinate, pneumatization of unciform process, Haller's cells, prominent agger nasi cell and ethmoid bulla. The endoscopic endonasal surgery landmarks, the individual morphologic variations, the topographic relations to the orbit and to the brain are also well shown by CT.     

The role of the ostiomeatal unit anatomic variations in inflammatory disease of the maxillary sinuses

Objective: The purpose of the study was to determine the correlation between bony anatomic variations of the ostiomeatal unit (OMU) and chronic maxillary sinusitis. The study was based on the hypothesis that the mucosal contact caused by the variations represents the critical factor in increasing the risk of maxillary sinusitis. Materials and methods: Thin section high resolution computerised tomography (CT) examinations of the paranasal sinuses in 73 consecutive patients with 113 anatomic variations of the OMU were retrospectively reviewed. The following CT features were assessed: (1) Type of anatomic variations, (2) presence of a mucosal contact in the OMU and (3) presence of maxillary disease. Statistical evaluation was carried out using z²-test. Results: The following bony anatomic variations were found: Concha bullosa (67 cases), abnormalities of the uncinate process (18 cases), Haller's cells (24 cases) and large ethmoidal bulla (four cases). Only 52 of the 113 anatomic variations were associated with ipsilateral maxillary disease (mucosal thickening, mucous retention cysts, polyps, retained secretions). Of 113 variations, 44 caused a mucosal contact, 35 of these were associated with maxillary abnormalities, while in nine cases there were no pathologic changes. Of 69 variations, 17 did not cause mucosal contact (P < 0.05). Conclusion: Our data shows that, in the presence of anatomic bony variations, a contact between the mucosal surface of the OMU is valuable in predicting the likelihood of a maxillary inflammatory disease.     

Benign expansile lesions of the sphenoid sinus: differentiation from normal asymmetry of the lateral recesses

BACKGROUND AND PURPOSE: There is a wide range of normal variation is sphenoid sinus development, especially in the size of the lateral recesses. The purpose of this study was to determine imaging characteristics that may help differentiate between opacification of a developmentally asymmetric lateral recess and a true expansile lesion of the sphenoid sinus. METHODS: Coronal CT was performed in seven patients with expansile or erosive benign lesions of the sphenoid sinus, and results were compared to a control population of 72 subjects with unopacified sphenoid sinuses. The degree of asymmetry of lateral recess development was assessed with particular attention to the separation of vidian's canal and the foramen rotundum (vidian-rotundum distance). The images were also examined for evidence of: erosion, defined as loss of the normal thin bony margin on at least two contiguous sections; apparent thinning of the sinus wall, defined as a focal apparent decrease in thickness again on at least two contiguous sections; and for vidian's canal or foramen rotundum rim erosion or flattening. RESULTS: Of the seven patients with expansile lesions, vidian's canal margin erosion was present in seven, unequivocal sinus expansion in three, wall erosion in three, wall thinning in three, erosion of the foramen rotundum in two, and flattening in the foramen rotundum in four. Forty-one of the 72 controls had lateral recess formation, 28 of which were asymmetric. The distance between vidian's canal and the foramen rotundum (vidian-rotundum distance) relied on the presence or absence of pneumatization, with a significantly larger distance in the presence of greater wing pneumatization. Examination of 24 controls revealed apparent thinning of the sinus wall, typically at the carotid groove, but no flattening, thinning, or erosion of the vidian canal or of the foramen rotundum. CONCLUSION: Examination of controls and patients with expansile or erosive lesions of the sphenoid sinus revealed side-to-side asymmetry in the development of the sinus and lateral recess, making subtle expansion difficult to assess. Furthermore, variability in the vidian-rotundum distance correlated with degree of pneumatization, and did not necessarily reflect expansion. Thus, in the absence of gross sinus wall erosion, flattening or erosion of the rims of vidian's canal or the foramen rotundum provides the most specific evidence of an expansile or erosive process within the sinus.     

Protrusion of the Infraorbital Nerve into the Maxillary Sinus on CT: Prevalence,Proposed Grading Method,and Suggested Clinical Implications

BACKGROUND AND PURPOSE:The infraorbital nerve arises from the maxillary branch of the trigeminal nerve and normally traverses the orbital floor in the infraorbital canal. Sometimes, however, the infraorbital canal protrudes into the maxillary sinus separate from the orbital floor. We systematically studied the prevalence of this variant.MATERIALS AND METHODS:We performed a retrospective review of 500 consecutive sinus CTs performed at our outpatient centers. The infraorbital nerve protruded into the maxillary sinus if the entire wall of the infraorbital canal was separate from the walls of the sinus. We recorded the length of the bony septum that attached the infraorbital canal to the wall of the maxillary sinus and noted whether the protrusion was bilateral. We also measured the distance from the inferior orbital rim where the infraorbital canal begins to protrude into the sinus.RESULTS:There was a prevalence of 10.8% for infraorbital canal protrusion into the maxillary sinus and 5.6% for bilateral protrusion. The median length of the bony septum attaching the infraorbital canal to a maxillary sinus wall, which was invariably present, was 4 mm. The median distance at which the infraorbital nerve began to protrude into the sinus was 11 mm posterior to the inferior orbital rim.CONCLUSIONS:Although this condition has been reported in only 3 patients previously, infraorbital canal protrusion into the maxillary sinus was present in >10% of our cohort. Identification of this variant on CT could help a surgeon avoid patient injury.

CT of the paranasal sinuses is an important diagnostic technique in the work-up of patients with known or suspected disease of the nasal cavity and paranasal sinuses. CT gives the surgeon a roadmap for surgery and alerts the surgeon to the presence of potentially clinically relevant anatomic variants. Many sinonasal variants are important to identify since their presence may increase the risk of surgical error.¹ With the advent of endoscopic techniques, surgery of the paranasal sinuses has expanded to involve complex procedures that were once reserved for open approaches. Thus, it is extremely important to identify such variations from the normal sinus anatomy, especially in patients who are likely to require extended endoscopic sinus surgery for etiologies such as inverted papilloma, mucocele, trauma, or malignant tumor.The infraorbital nerve is the distal portion of the maxillary nerve (V2), which originates as the second division of the trigeminal nerve (fifth cranial nerve). After the maxillary nerve traverses the foramen rotundum, it enters the pterygopalatine fossa and gives off nasal and palatine branches before exiting through the inferior orbital fissure and terminating as the infraorbital nerve (ION). The ION then enters the infraorbital canal (IOC) through the infraorbital groove. The IOC is a bony canal typically within the orbital process of the maxilla, synonymous with the floor of the orbit. The ION exits the IOC through the infraorbital foramen of the anterior maxilla. Variably, the IOC can protrude into the maxillary sinus separate from the floor of the orbit. This may leave the ION susceptible to injury during endoscopic or open sinus surgery. To date, just 3 case reports exist in the literature describing this variant,^2,3 with no large studies describing the frequency with which it occurs. The aim of this study was to establish the prevalence of infraorbital nerve protrusion into the maxillary sinus and define its common characteristics. This variation is of clinical importance in sinus surgery, and we suggest an accompanying grading scale to relay the degree of protrusion to the surgeon.     

CTVE技术在神经内镜经鼻蝶窦垂体腺瘤手术中的应用价值

目的探讨CTVE技术在神经内镜经鼻蝶窦垂体腺瘤手术中的应用价值。方法在20例行鼻蝶窦垂体腺瘤手术患者中,对常规术前垂体CT检查数据进行CTVE重建,将其用于术前计划以及术中定位。对CTVE显示的鞍底三维图像与术中显微镜所见图像进行对比分析。结果 CTVE能以三维图像的形式对鞍底解剖结构进行显示,对解剖结构：蝶窦内隔、鞍底、颈内动脉隆起、视神经管隆起以及O-C隐窝的显示率分别为100.00%、100.00%、42.50%、40.00%及72.50%,均显著高于术中显微镜显示范围;通过对观察阈值的调高,CTVE可以清楚地显示鞍底深面的颈内动脉、垂体组织、部分视神经管,通过二维图像,可准确地标出肿瘤在CTVE图像上的具体部位。结论 CTVE可显示蝶窦以及鞍底的表面解剖标志同深面结构的三维解剖之间的关系,在经鼻蝶窦垂体腺瘤手术中,CTVE能够很好地指导术前计划以及术中定位。     

Hypoplasia of the sphenoid sinuses as a diagnostic tool in cystic fibrosis.

PURPOSE: To measure and compare the size of the sphenoid sinuses in patients with cystic fibrosis (CF) to patients with inflammatory sinonasal disease, and to correlate the size with number of CF mutations in each patient. MATERIAL AND METHODS: Ninety-six CF patients aged 5-47 years (median 19 years) and 130 control patients aged 7-51 years (median 32 years) were examined using coronal CT of the paranasal sinuses. In each patient, the CT image with the largest coronal area of the sphenoid sinuses was scanned into a Macintosh computer with image processing and analysis software. Largest coronal area and largest circumference of the right and left sphenoid sinuses were automatically measured. Additionally, antero-posterior extension of the sphenoid sinuses was calculated from the lateral scanograms. CF patients were grouped according to number of confirmed mutations (CF-0, CF-1, or CF-2). RESULTS: CF patients generally had small sphenoid sinuses. The largest differences for all parameters were observed between the CF-2 and the control groups (p<0.0001). No CF-2 patient had pneumatization beyond the presphenoid. The CF-0 and CF-1 groups consisted of two populations, one overlapping the CF-2 group and another overlapping the control group. CONCLUSION: Hypoplasia of the sphenoid sinuses is a characteristic finding in CF patients. When pneumatization of the basisphenoid is present, the existing CF diagnosis should be questioned.     

螺旋CT三维重建评价筛窦解剖变异及临床意义

目的：探讨应用螺旋CT对筛窦进行三维图像重建，认证筛窦解剖变异及临床意义。材料和方法：应用GE Lightspeed Plus多排螺旋机扫描仪，对75例病例进行筛窦横断面扫描，通过GE W4．0工作站，在三维重建软件支持下作冠状位图像重建。结果：筛窦常见的解剖变异有5种：筛大泡占52％，Onodi气房21％，眶五气房5％，筛凹低位4％，纸样板过度内移7％。结论：经横断面CT扫描，通过三维重建，能够很好地显示筛窦冠状面图像及其解剖变异，为手术提供详细的影像学资料，对鼻内镜外科有重要临床指导意义。     

鼻窦真菌病的CT诊断

探讨鼻窦真菌病的ＣＴ表现特征。材料和方法：回顾分析１０３例手术和病理证实的鼻窦真菌病的ＣＴ表现，其中累及上颌窦及蝶窦分别为９３和１０例。结果：病变未充满窦腔５６例（５４．４％），充满窦腔４７例（４５．６．％）。密度不均匀８７例（８４．４％），均匀１６例（１５．６％）。全窦腔受累者，基病变中心密度高于外周密度；病变涉及部分窦腔者显示为中央不规则的高密度软组织团块影伴窦壁黏膜增厚。９３例上颌窦真菌中，     

Significance of CT and MR findings in sphenoid sinus disease

Disorders of the paranasal sinuses, particularly the sphenoid sinus, can be associated with significant disorders of the optic and other cranial nerves. We examined 100 consecutive routine CT scans, 100 posterior fossa CT scans, and 100 MR scans to look for evidence of sinus disease, especially of the sphenoid sinus. The sphenoid sinus was abnormal in 7% of scans by all methods. Other sinuses were more frequently abnormal, including maxillary (23%), ethmoid (34%), and frontal (16%). Although MR was more sensitive in detecting sinus inflammation in the ethmoid and maxillary sinuses, the frequency of visible sphenoid sinus abnormalities detected by MR was not significantly greater when compared with CT. Of those patients with abnormal sphenoid sinuses, 24% had visual problems associated with the abnormality.     

MRI of growth hormone-secreting pituitary adenomas: factors determining pretreatment hormone levels

Preoperative serum growth hormone (GH) level is one of the most important determinants of outcome. Our aim was to assess MRI findings which may correlate with pretreatment GH levels in GH-secreting adenomas. We retrospectively studied 29 patients with acromegaly caused by a pituitary adenoma. Tumor size (height, width, thickness and volume), suprasellar extension, sphenoid or cavernous sinus invasion, signal intensity and contrast enhancement were studied. Linear regression analysis or Fisher's exact probability test was used for statistical analysis. Factors related to high GH levels were the maximum dimension of the tumour (r = 0.496, P < 0.01), its volume (r = 0.439, P < 0.05), spenoid sinus invasion (P < 0.01) and intracavernous carotid artery (encasement (P < 0.01). The other items were not related to serum GH levels. Since we believe surgery is the first choice of treatment and the cavernous sinus is difficult of access with a conventional surgical approach, preoperative assessment of invasion into the cavernous sinus is critical for predicting the surgical outcome. Low GH levels (5–50 ng/ml) were found with tumours medial to the intercarotid line and high levels (more than 101 ng/ml) with invasive tumours with carotid artery encasement. Variable GH levels were noted with tumours extending beyond the intercarotid line. Because functioning adenomas invading the cavernous sinus tend to have markedly high hormone levels, and only patients with carotid artery encasement showed markedly elevated GH levels, we believe carotid artery encasement a reliable MRI indicator of cavernous sinus invasion. Received: 1 January 1998 Accepted: 18 March 1999     

MR imaging of nonmalignant polyps and masses of the nasopharynx and sphenoid sinus after radiotherapy for nasopharyngeal carcinoma

BACKGROUND AND PURPOSE: The development of a new polyp or mass in the radiation field of a previously treated carcinoma is usually an ominous sign of a recurrent cancer, but rarely may it be caused instead by a nonmalignant process. The purpose of this study was to document the MR appearance of unusual nonmalignant polyps or masses (NMPMs) in the nasopharynx and sphenoid sinus arising after radiation treatment of nasopharyngeal carcinoma.MATERIALS AND METHODS: The MR imaging reports of patients undergoing imaging after radiation therapy for nasopharyngeal carcinoma were reviewed retrospectively to identify patients with unusual polyps and masses in the nasopharynx. The MR images of those patients with no evidence of malignancy on biopsy or follow-up were reviewed.RESULTS: The MR imaging reports of 1282 patients were reviewed, and 11 patients (1%) with NMPMs in the nasopharynx or sphenoid sinus were identified. Two patterns were identified: contrast enhancing nasopharyngeal polyps ranging in size from 1 to 5 cm (n = 5) and sphenoid sinus masses consisting of a nonenhancing mass filling a nonexpanded sinus (n = 4) and a heterogeneous enhancing mass expanding the sinus (n = 2). Osteoradionecrosis produced a large defect in the roof of the nasopharynx causing direct communication with the sphenoid sinus (n = 6). Histology revealed granulation tissue in all of the patients with variable amounts of fibrin and inflammatory cells. A direct infective etiology was not proved in any patient.CONCLUSION: NMPMs in the nasopharynx and sphenoid sinus are rare complications after radiation therapy to the skull base, but the radiologist needs to be aware of their appearance so that they can be considered in the differential diagnosis of suspected tumor recurrence.

The rapidly dividing cells in the mucosal membranes of the pharynx and paranasal sinuses are very sensitive to the effects of radiation. The severity of radiation damage after treatment of head and neck cancers is related to radiation dose and potentially is increased by the use of chemotherapy and altered fractionation schedules of radiation therapy.¹ The naso-pharynx and sphenoid sinus are especially vulnerable to the effects of radiation treatment of nasopharyngeal carcinoma, because they receive the full radiation dose. Acute mucositis is a consistent clinically visible adverse effect during the standard course of radiation therapy for head and neck cancers. It starts around the second to third week of treatment and usually subsides several weeks after the end of treatment.² Likewise, acute radiation change can be seen on MR imaging. In the pharynx, these MR abnormalities often resolve, whereas in the paranasal sinuses there is a high incidence of persistent minor abnormalities, including mucosal thickening and fluid levels, months or years after treatment for nasopharyngeal carcinoma.^3–5 Rarely a mucocele may form in the sphenoid sinus.⁶ However, there are some patients who go on to develop severe delayed radiation effects resulting in the formation of unusual nonmalignant polyps and masses (NMPMs) in the nasopharynx and sphenoid sinus. These radiation-induced injuries cause both clinical and radiologic problems with distinction from recurrent cancer, as well as being a cause of serious morbidity and even mortality. The aim of this study was to describe these abnormalities in patients undergoing MR imaging after radiation therapy for nasopharyngeal carcinoma.     

Reduced Field-of-View Diffusion Tensor Imaging of the Optic Nerve in Retinitis Pigmentosa at 3T

BACKGROUND AND PURPOSE:Diffusion tensor imaging may reflect pathology of the optic nerve; however, the ability of DTI to evaluate alterations of the optic nerve in retinitis pigmentosa has not yet been assessed, to our knowledge. The aim of this study was to investigate the diagnostic potential of reduced FOV–DTI in optic neuropathy of retinitis pigmentosa at 3T.MATERIALS AND METHODS:Thirty-eight patients and thirty-five healthy controls were enrolled in this study. Measures of visual field and visual acuity of both eyes in all subjects were performed. A reduced FOV–DTI sequence was used to derive fractional anisotropy, apparent diffusion coefficient, principal eigenvalue, and orthogonal eigenvalue of the individual optic nerves. Mean fractional anisotropy, ADC, and eigenvalue maps were obtained for quantitative analysis. Further analyses were performed to determine the correlation of fractional anisotropy, ADC, principal eigenvalue, and orthogonal eigenvalue with optic nerves in patients with mean deviation of the visual field and visual acuity, respectively.RESULTS:The optic nerves of patients with retinitis pigmentosa compared with control subjects showed significantly higher ADC, principal eigenvalue, and orthogonal eigenvalue and significantly lower fractional anisotropy (P < .01). For patients with retinitis pigmentosa, the mean deviation of the visual field of the optic nerve was significantly correlated with mean fractional anisotropy (r = 0.364, P = .001) and orthogonal eigenvalue (r = −0.254, P = .029), but it was not correlated with mean ADC (P = .154) and principal eigenvalue (P = .337). Moreover, no correlation between any DTI parameter and visual acuity in patients with retinitis pigmentosa was observed (P > .05).CONCLUSIONS:Reduced FOV–DTI measurement of the optic nerve may serve as a biomarker of axonal and myelin damage in optic neuropathy for patients with retinitis pigmentosa.

Retinitis pigmentosa (RP) is a common refractory visual disease and accounts for a large proportion of hereditary visual impairment. It is characterized by the progressive death of rod and cone photoreceptors, which leads to corresponding visual field (VF) defects.¹ As a heterogeneous group of inherited retinal degenerative diseases,² RP displays extreme genetic heterogeneity. More than 80 disease genes have been identified so far, 58 of which correspond to nonsyndromic RP.³ Clinical features of RP include night blindness, progressive loss of peripheral VFs, reduced or nondetectable electroretinogram amplitudes, and characteristic pigmentary degenerative changes of the retina.Several studies observed that the retinal nerve fiber layer, formed by expansion of optic nerve (ON) fibers, is significantly thinner in patients with RP by using optical coherence tomography,^4,5 which reflects the changes of the ON in RP. Furthermore, the occurrence of optic neuropathy in RP was confirmed by a postmortem study that showed that total axon counts of the ON were significantly decreased in patients with end-stage RP compared with healthy controls.⁶ However, in vivo diagnosis of optic neuropathy in patients with RP remains challenging because conventional MR imaging and ophthalmologic examinations often fail to detect ON disease.Recently, DTI has emerged as a noninvasive imaging method with great potential to investigate the morphology and function of the ON in vivo.^7,8 However, there has been no study of DTI in optic neuropathy of RP to date, especially reduced FOV–DTI (rFOV-DTI) at 3T, which has the potential advantages of improved signal-to-noise ratio and reduced susceptibility-related artifacts over conventional DTI.^9,10 This study set out to investigate the potential clinical utility of rFOV-DTI in diagnosing optic neuropathy in RP at 3T. Specifically, we hypothesized that quantitative rFOV-DTI might reveal the injury to the ON of RP, which may be related to visual functions, including both VF and visual acuity (VA).     

CT检查在FESS术前计划制定中的价值

目的:探讨蝶窦与视神经、颈内动脉等邻近结构的CT影像解剖关系,为经蝶窦手术及诊断提供准确的影像解剖学依据。方法:CT扫描病例128例,年龄20～72岁,平均46.2岁;其中男79例,女49例。使用日本TOSHIBA公司生产的Aquilion 4螺旋CT。后台处理采用Vitrea 1处理系统。测量数据采用x±SD,百分数,t检验。结果:视神经管与蝶窦的关系:隆起型视神经管38例(29.69%),压迹型视神经管73例(57.03%),远离型视神经管17例(13.28%)。视神经走行与蝶窦外侧的关系:全程与蝶窦外侧壁毗邻者71侧(27.73%),全程与后组筛窦毗邻者66侧(25.78%),全程同时与蝶筛外侧壁毗邻者95侧(37.11%),全程穿过骨质者22侧(8.59%)。颈内动脉与蝶窦的关系:隆起型48侧(18.75%),压迹型101侧(39.45%),远离型107侧(41.80%)。结论:CT扫描结合MPR重组,能够清楚显示颈内动脉、视神经等与蝶筛外侧壁的解剖毗邻关系。CT检查有利于FESS手术进路的选择及手术方案的确定,为手术安全提供了保证。     

Investigation of the accessory maxillary ostium: a congenital variation or acquired defect?

Objective:We sought to determine whether an accessory maxillary ostium (AMO) is a congenital or acquired condition and we investigated concomitant sinus pathologies associated with this structure.Methods:Paranasal sinus CT examinations of individuals aged ≥13 years and <13 years were compared retrospectively. In total, 552 sinuses of 276 patients aged ≥13 years (Group 1) and 284 maxillary sinuses of 142 children aged <13 years (Group 2) were evaluated. Patients were classified as AMO-positive or -negative. The following features were evaluated in Group 1: AMO presence, mucus retention cysts, mucosal thickening, sinusitis of the maxillary sinus, nasal septum deviation, concha hypertrophy, concha bullosa, primary ostium obstruction, uncinate process atelectasis, paradox concha, Agger nasi and Haller cells, and sinus hypoplasia. The sizes and locations of AMOs were also evaluated. The presence of an AMO and sinusitis were evaluated in Group 2.Results:AMOs were detected in 122 sinuses in Group 1. In the AMO-positive group, sinusitis, mucosal thickening, and primary ostium obstruction were significantly more common than in the AMO-negative group (p < 0.00001). Statistically significant associations were not observed between AMO presence and other parameters. AMOs were present in two sinuses in Group 2.Conclusion:Our results suggest that AMOs are acquired defects caused by sinus diseases. The rare occurrence of these structures in patients aged <13 years suggests that they may be a perforation or secondary drainage pathway in patients with sinusitis or primary ostium obstruction.     

Sphenoid sinus barotrauma in diving: case series and review of the literature

About 50% of scuba divers have suffered from barotrauma of the ears and about one-third from barotrauma of paranasal sinuses. The sphenoid sinuses are rarely involved. Vital structures, as internal carotid artery and optic nerve, adjoin the sphenoid sinus. Thus, barotrauma could lead to serious neurologic disorders, including blindness. After searching the literature (Medline) and other sources (Internet), we present some cases of sphenoid sinus barotrauma, because these injuries may be underreported and misdiagnosed due to the lack of awareness and knowledge. Therefore, information is provided, e.g. on anatomical and pathophysiological features. Divers and physicians should have in mind that occasional headache during or after diving sometimes signals serious neurological disorders like vision loss. We show that injuries can develop from both negative and positive pressures in the sinuses. Because visual recovery depends on prompt diagnosis and proper therapy, physicians like otolaryngologists, ophthalmologists and neurologists need to closely collaborate.