High-resolution CT: pre-operative assessment of chronic and recurrent rhinosinusitis

The better understanding of chronic and recurrent rhinosinusitis and the advance in endoscopic endonasal surgery have modified the radiological pre-operative investigation of this condition. The ethmoid labyrinth, not accessible to the endoscope, may be explored by axial and coronal high-resolution thin section (2 mm) CT. We have reviewed 100 CT scans with endoscopic correlation in order to assess the accuracy of this pre-operative method.This anatomical study reveals the presence and extent of parasinus diseases which are usually concentrated in the area of the ostiomeatal unit. The anatomic variations of the lateral nasal wall that have been reporded as predisposing to sinusitis and the morphologic variations altering the relationships of the ethmoid with the orbits and the brain were also studied. This pre-operative radiological assessment is currently necessary for functional and safe surgery.Correspondence to: J. C. FerriePaper presented at ECR 1991     

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.     

筛骨解剖变异的CT评价及其临床意义

目的 评价冠状位CT对功能性内镜鼻窦外科有关的筛骨解剖变异的显示能力，讨论筛骨解剖变异的CT评价对临床手术的指导意义。资料与方法 冠状位CT薄层扫描整个筛骨45例，以筛骨的断层为依据，以内镜鼻窦手术为对照，认证筛骨的解剖变异，并计算各种变异的出现率。结果 筛顶的解剖学特征中，倾斜式占73．3％，高台式占26．7％；蝶上筛房占13．3％；眶下筛房占8．9％；中鼻甲的气化和反向偏曲各占17．8％和2．2％；鼻中隔的气化占6．7％，偏曲占22．2％，形态呈S型、弧型、侧置V型等。结论 冠状位CT能很好显示有关内镜鼻窦手术的筛骨解剖变异，为手术提供详细的影像学资料，对该手术有很大的指导意义。     

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。     

Evaluation of variations in sinonasal region with computed tomography

AIM: To investigate the frequency of anatomical variations in sinonasal region and association of these variations with mucosal diseases.METHODS: The study included 400 cases (191 female and 209 male) who were considered to have preliminary diagnoses of sinonasal pathology and who had paranasal sinus computed tomography (CT) examination in axial plane. Reformatted CT images were studied in all planes.RESULTS: Age range of the patients was 20-83 (mean 40.26 ± 14.85). Most commonly detected anatomical variation was Agger nasi cell (74.8%). There was a significant association between clinoid process pneumatization and protrusion of internal carotid arteries and optic nerves into sphenoid sinus (P < 0.001). Besides, the relationships between pterygoid process pneumatization and protrusion of vidian nerve into sphenoid sinus, and between pneumatization of large sphenoid wing and protrusion of maxillary nerves into sphenoid sinus were also significant (P < 0.001). Uncinate bulla and giant ethmoid bulla were found to be significantly associated with sinonasal mucosal diseases (P = 0.004 and P = 0.002, respectively).CONCLUSION: Sinonasal region has a great number of variations, and some of them have been determined to be associated with sinonasal mucosal disease. It is necessary to know that some of these variations are associated with protrusion of significant structures such as carotid artery or optic nerve into the sinus and care should be observed in surgeries on patients carrying these variations.     

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.     

X-ray computed tomographic study of the ethmoid and middle meatus. I. radioanatomy (coronal plane)

The advance of endoscopic endonasal surgery allows limited surgical resection in chronic rhinosinusitis. An accurate topographic evaluation of diseases and individual morphologic variation are necessary for this functional surgery. The preoperative radiological investigations require a precise knowledge of ethmoid and osteo-meatal unit anatomy. Thin sections by high resolution CT were performed in coronal plane. The anatomical land marks and the ethmoidal bony roots, which allow a study of the osteo-meatal unit and ethmoid air cells system, are showed. Like endoscopic view, coronal slices better display the different grooves for paranasal sinus draining and their relations with the ethmoid.     

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     

Topographic anatomy of the ethmoid labyrinth in x-ray computed tomography

These last years the surgical treatment of inflammatory ethmoid disease has been completely modified, with new endoscopic conservative procedures. In a preoperative phase it is mandatory to provide optimal CT imaging of the ethmoid labyrinth, and for this purpose sections perpendicular and parallel to the nasofrontal duct axis are better than axial and coronal slices. The anatomy of the ethmoid is fairly complex; however certain constant anatomic landmarks allow a systematic analysis of the ethmoid labyrinth: the unciform process, the bulla, the middle turbinate, the superior turbinate and their respective basal lamellae.     

蝶筛区域解剖结构的CT评价及对功能性内窥镜鼻窦外科的指导意义

目的探讨CT对蝶筛区域解剖结构的评价能力,以期为功能性内窥镜鼻窦外科手术提供帮助。材料和方法冠状和横轴位薄层CT扫描54例无病变的蝶筛区域,并重建矢状位图像。结果CT图像中蝶上筛房出现率13.0％。蝶窦气化CT分型中,甲介型占8.3％,半鞍型占51.9％,全鞍型占39.8％。蝶窦中隔居正中位置占24.1％。蝶窦的其他变异有翼突气化、前床突气化、蝶骨大翼气化和蝶骨小翼气化。视神经管纵轴与蝶筛窦的毗邻关系在CT图像上分为三型,视神经管横轴对蝶筛窦的压迫关系分为四型,并统计出各型的分布情况。结论CT扫描能显示蝶筛区域与功能性内窥镜鼻窦外科手术有关的绝大部分解剖结构及其变异,对手术有很大的指导作用。     

X-ray computed tomographic evaluation of the anterior ethmoid by parallel and perpendicular sections to the axis of nasofrontal duct. Preliminary study

The anterior ethmoid is revisited with CT sections parallel and perpendicular to the axis of the naso-frontal duct. The sections obtained in these 2 planes allow a more precise topographic study of the anterior ethmoid than the routinely used axial and coronal CT slices. For the surgeon these sections provide an optimal preoperative study of the anterior ethmoid allowing the most conservative endoscopic surgical treatment.     

CT evaluation of pterygoid process pneumatization and the anatomic variations of related neural structures

Objective

This topic is concerned with the clarification of the radiological findings that should be reported as regard the anatomic variations of the neural structures related to the pterygoid process in patients listed for endoscopic sinus surgery.

Concha bullosa and the nasal middle meatus obstructive syndrome

BACKGROUND: Concha bullosa (CB) is pneumatization of the middle turbinate and one of the most common anatomic variation of the sinonasal region. It is found in about 25% of the population. Middle meatus obstructive syndrome (MMOS) is, usually connected with CB. The main symptoms of this syndrome are headaches, impaired nasal breathing and hyposmia. Headache is the most common symptom and it may occur due to contact between a CB and other structures of the nasal cavity. CASE REPORT: We presented a case of 32 year-old-woman with headaches, located in the orbital and the left frontal region. The headaches were intermittent and corresponding to the nasal cycle. After neurologic and allergic examination, endoscopic nasal examination demonstrated a septal deviation to the right side and a large middle turbinate in the left side of the nasal cavity. Coronal computerized tomography (CT) of the paranasal sinuses demonstrated the septal deformation and pneumatization of the left middle turbinate. Diagnosis was confirmed by lidocaine test. In the functional endoscopic surgery (FESS), the lateral lamela of the anterior CB was removed. At the same time, the septoplasty was done. At the control examination, the patient was without symptoms. CONCLUSION: Although CB is the common anatomic variation of the nasal cavity, MMOS is rare. Headache (rhinogenic origin) is the most important symptom. Surgical treatment is the lateral resection of the CB in the FESS technique and the septoplasty.     

The frontal intersinus septal air cell: a new hypothesis of its origin

BACKGROUND AND PURPOSE: Air cells are often seen within the frontal intersinus septum. These cells have traditionally been thought to arise from displaced ethmoid cells from the frontal recess. This study explores the possibility that such cells may actually be diverticula from the frontal sinuses themselves and not of a direct ethmoid origin.MATERIALS AND METHODS: A prospective study of 200 consecutive CT scans in the coronal and axial planes was performed on patients without a history of recent trauma. The images were interpreted independently by a radiologist and an otolaryngologist. The CT studies were evaluated for the presence of a central intersinus septal air cell. If such a cell was identified, it was further classified as either being completely isolated from both frontal sinuses by a bony rim or as a communicating diverticulum from one of the frontal sinuses. If a central cell was present, it was also assessed for how much of the height of the intersinus septum it involved (lower one-half or full height).RESULTS: There was a complete concordance of the results between the 2 observers. An intersinus septal air cell was seen in 61 (30.5%) of the 200 cases, and 85.3% of these cells were clearly seen to communicate anteromedially with either one of the frontal sinuses or both frontal sinuses (3 cases). In 9 (4.5%) of the 200 cases, the central cell had no demonstrable connection to either frontal sinus. Of the 61 cases with a central cell, 55 (90.16%) of the cells occupied the full height of the septum, and 6 (9.84%) only involved the lower half of the septum.CONCLUSION: Contrary to the present convention that frontal intersinus septal cells originate as displaced ethmoid cells from the frontal recess, we found that most such cells are actually diverticula from the frontal sinuses themselves.

The development of the frontal sinus from the anterior ethmoid labyrinth allows for the presence of extramural ethmoid cells both around and within the frontal sinus proper. These cells, which communicate with the frontal recess, include supraorbital, infrafrontal, and intersinus septal cells. Such cells were identified by anatomic dissection studies in the first part of the 20th century and were subsequently detailed by radiographic imaging in living patients.^1–3The belief that there was a common embryogenesis of the frontal sinus and associated cells by evagination and pneumatization from the frontal recess have resulted in a generally accepted unifying hypothesis of their formation. However, our study challenges the concept that the intersinus septal cell is uniformly of an ethmoid derivation. Rather, we suggest that such a cell may most often represent a diverticulum from the frontal sinus itself.     

Ethmomaxillary sinus: a particular anatomic variation of the paranasal sinuses

We assessed the morphological and radiological characteristics of ethmomaxillary sinus (EMS), which is an enlarged posterior ethmoidal air cell occupying the superior portion of the maxillary sinus while draining into superior meatus. This study is based on 1450 patients submitted to CT examination of the paranasal sinuses between 1998 and 2002. Sequential CT scans were obtained in the coronal plane in all the patients with 2.5- to 5-mm section thickness and were evaluated for EMS. The diagnosis of EMS was made when there was a posterior ethmoidal cell occupying the superior part of the maxillary sinus while draining to the superior meatus. When EMS was diagnosed, the morphology of the septum between the and maxillary sinus, and width of the superior meatus, were noted. The EMS was found in 10 of 1450 (0.7%) patients. The coexisting anatomic variations were concha bullosa (50%), upper concha pneumatization (20%), maxillary sinus hypoplasia (20%), uncinate bulla (10%), hypertrophied inferior concha (10%), paradoxic middle concha (10%), and septate maxillary sinus (10%). There was no relation between EMS and sinus disease. The EMS is a rare anatomic variation and does not appear to be associated with sinusitis. The EMS is not a well-studied anatomic variation, and the literature is lacking adequate information about this anatomic variation. This study performed in a large series of patients will possibly contribute to better understanding of this particular anomaly.     

多层CT对窦口鼻道复合体解剖变异与慢性副鼻窦炎的关系的分析

目的:探讨窦口鼻道复合体(OMC)解剖变异与慢性副鼻窦炎的相关性。方法:收集经多层螺旋CT扫描的慢性副鼻窦炎100例。通过多平面重组重点观察钩突、中鼻甲、筛泡、鼻中隔的解剖变异,并和正常组进行对比,行统计处理并分析解剖变异与慢性鼻窦炎的关系。结果:慢性副鼻窦炎组窦口鼻道复合体解剖变异为89%,其中钩突改变25%,筛漏斗狭窄14%,中鼻甲改变22%,鼻中隔改变20%,多种解剖变异8%;正常组中窦口鼻道复合体解剖变异为19%,其中钩突改变1%,中鼻甲改变6%,鼻中隔改变12%。窦口鼻道复合体解剖变异与慢性副鼻窦炎呈正相关(P<0.05)。结论:慢性副鼻窦炎与窦口鼻道复合体的解剖变异有明显的相关性,CT检查发现泛发性副鼻窦炎时,应重点观察窦口鼻道复合体,为临床治疗提供详细的依据。     

慢性额窦炎额窦引流系统CT解剖特征及临床价值

目的 探讨慢性额窦炎额窦引流系统CT解剖特征及临床价值。方法 对50例慢性鼻窦炎患者应用螺旋CT作横断面扫描，然后经工作站作冠状和矢状面三维重建。结果 螺旋CT三维成像技术能清楚地显示钩突附着部位和类型，在：100侧钩突中，附着纸样板41侧(41％)、鼻丘后壁11侧(11％)、中鼻甲19侧(19％)、前颅底16侧(16％)、钩突分叉13侧(13％)。在额隐窝气房98侧中，终未气房28侧(28．6％)、鼻丘气房18侧(18．4％)、前筛气房18侧(18．4％)。额窦内气房98侧中，其中额气房22侧(22．4％)、眶上气房38侧(38．8％)、额窦中隔气房(M气房)16侧(32％)。发现不同类型的解剖变异与慢性炎症的关系。结论 慢性额窦炎额窦引流系统CT解剖特征的显示可为术前提供有价值的信息，对开展鼻内镜外科有重要的临床指导意义。     

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.     

Colonoscopy with computed tomography with volume reconstruction. The results and a comparison with endoscopy and surgery

PURPOSE: Virtual CT colonoscopy is a novel technique whose diagnostic accuracy and clinical yield are currently investigated. Several studies have shown its capabilities in detecting colon and rectal cancers. We report the results of a preliminary experience with the volume rendering technique and compare CT colonoscopy with endoscopy and surgery. MATERIAL AND METHODS: Our series consisted of 25 patients with colon cancer confirmed at endoscopy and/or surgery. All examinations were carried out with a spiral CT scanner Philips Tomoscan AVE1. Intestinal preparation was adequate in all patients, consisting in gas insufflated immediately before acquisition, after the injection of 100 mL iodinated contrast agent. All examination were performed in prone position using axial 5 mm slices with 5 mm table feed (pitch 1) and 2 mm reconstruction index; 120 kV and 200-250 mA were used. Images were transferred to a workstation (Easy Vision, Philips, release 4.2.1.1) for processing. We acquired multiplanar (MPR) and virtual endoscopic images with volume rendering; the selected threshold was -250 to -600 Hounsfield Units. Virtual endoscopic images could be obtained in 23 of 25 cases. The results of the radiological study were compared with endoscopic and surgical findings in 25 and 17 cases, respectively. RESULTS: Endoscopy and surgery detected 46 lesions: 29 were malignant and 17 benign. Axial CT and MPR alone detected 35 lesions (76%), 29 of them malignant and 6 benign. The 11 benign lesions missed by axial CT ranged 6-8 mm in diameter. There were no false positives. CT colonoscopy alone detected 66 lesions, but 22 of them were false positive due to residual stool in the colon (21 cases) and to residual barium in the colon (1 case). Combining CT colonoscopy and axial and MPR images enabled to correct the false positive diagnoses made by CT colonoscopy alone and to decrease the false negative ratio of axial and MPR images. Forty-one of 44 lesions (93%) were detected. Thirty-seven lesions were found in the 17 surgical patients; 34 of them were correctly identified combining CT colonoscopy and axial and MPR findings, while endoscopy detected only 31 lesions. Thus, CT had 92% sensitivity, versus 83% of fiberoptic endoscopy. CONCLUSION: In this preliminary experience volume rendering CT colonoscopy exhibited high sensitivity in detecting colon cancers, but their correct evaluation and characterization can be obtained if axial and MPR studies are combined. Further investigation and technological developments are necessary to define the yield of this new technique.     

Identification of the anterior ethmoid arteries on thin-section axial images and coronal reformatted orbit images by means of multidetector row CT

AIM: The aim of this study was to identify anterior ethmoid arteries on thin-section axial images and coronal reformatted images of the orbits using multidetector row computed tomography (CT). MATERIALS AND METHODS: One hundred and thirty-two patients underwent paranasal CT using a 16-row detector CT (n=59) or a 6-row detector CT machine (n=73) at 1 or 1.25 mm section width, respectively. Coronal images were reformatted at section widths of 3 and 1 mm. The anterior ethmoid arteries were identified for each patient. Differences were assessed using the chi-square test. RESULTS: All CT images were of approximately average diagnostic quality. Anterior ethmoid arteries were identified in 97.5 and 96.6% at section thicknesses of 1 and 1.25 mm on the axial images, respectively. There was no statistically significant difference in the detection rate (p=0.89). On the coronal images, anterior ethmoid arteries were presented tangentially in 75.4 and 90.2% at section widths of 3 and 1 mm, respectively. The visibility of the anterior ethmoid arteries was rated significantly better on coronal images at a section width of 1 mm than on those at section widths of 3 mm (p<0.001). CONCLUSION: Thin-section axial images and coronal reformatted images using multi-detector row CT mostly depict anterior ethmoid arteries, and are useful to identify anterior ethmoid arteries for preoperative evaluation of paranasal sinuses.