Value of secondary coronal reconstructions in computed tomography of the paranasal sinuses

INTRODUCTION: Before sinus surgery, computed tomography (CT) of the paranasal sinuses and anterior skull base is a standard procedure in the diagnostic evaluation. However, coronal sections necessary for the analysis of the complex anatomy of this region are often not applicable in multiple injured or elderly patients due to the impossibility to maintain the required position for the coronal scans. Secondary coronal reconstruction of primary axially acquired scans could help to overcome this problem. This technique was, however, hampered so far by an insufficient resolution in case of conventional CT. We therefore compared the quality of primary coronally acquired conventional CT images with the resolution of multiplanar reformatted coronal images of primary axially acquired scans by means of a new CT generation, the Multidetector Computed Tomography (MDCT). MATERIAL AND METHODS: 10 patients were each examined with conventional CT or MDCT respectively. The quality of primary coronally acquired conventional scans (CT) versus secondary coronal reconstructions (MDCT) was compared by evaluating typical anatomic landmarks. RESULTS: As compared to conventional CT, the coronal reconstruction of primary axially acquired scans by means of MDCT revealed an equal resolution and additionally no essential impairment by amalgam artefacts. CONCLUSION: Our results demonstrate the excellent quality of secondary coronal reconstructions by means of MDCT in the CT evaluation of the paranasal sinuses and the anterior skull base as compared to primary coronally acquired images via conventional CT.     

多层螺旋CT冠状面重建对窦口鼻道复合体解剖变异及鼻窦炎的诊断价值

目的探讨多层螺旋CT多平面重建技术对窦口鼻道复合体（OMC）解剖变异及鼻窦炎症的诊断价值。方法34例经临床证实的鼻窦炎患者,均作了64层CT容积扫描,经CT32作站行冠状面重建,观察鼻窦炎的病变范围及OMC的显示情况。结果34例患者冠状位重建均显示了中鼻甲、钩突、筛漏斗、半月裂及筛泡等OMC结构,其中21例存在OMC结构变异,包括中鼻甲气化（38．1％,8／21）,反向弯曲（4．8％,1／21）;钩突肥大（14．3％,3／21）、偏移（4．8％,1／21）,气化（4．8％,1／21）;筛泡过度气化（14．3％,3／21）,Hailer气房（14．3％,3／21）,鼻丘过度气化（4．8％,1／21）等。结论多层螺旋CT冠状面重建能清楚地显示OMC区域的解剖结构及变异情况,为鼻窦炎及其原因的临床诊断提供可靠的影像资料。     

High-resolution petrous bone imaging using multi-slice computerized tomography

Multi-slice computerized tomography (MSCT) is considered to provide superior image quality. We defined a data acquisition protocol for high-resolution (HR) temporal bone imaging using MSCT and assessed its impact on data acquisition and post-processing (PP). The data acquisition protocol was defined in cadaveric phantom studies performed by MSCT and subsequently applied to 38 patients referred for temporal bone assessment. The parameters image quality and diagnostic value of MSCT data were assessed for the cross-sectional source images as well as for 2-dimensional (2D) reformations and 3-dimensional (3D) reconstructions by 3 radiologists by comparison with incremental HR scans of 17 patients with suspected middle ear disorders. The data acquisition protocol yielded HR images with an excellent detail resolution and a comparable image quality of cross-sectional scans and related orthogonal reformations. MSCT achieved higher scores for image quality and diagnostic value (p < 0.001, t-test) than incremental HR CT with regard to both 2D and 3D reconstructions. MSCT improves the image quality of HR cross-sectional scans as well as that of 2D and 3D PP techniques in petrous bone imaging. The radiation exposure of the eye lenses is increased by MSCT as gantry angulation is not yet possible in the helical scan mode.     

High-resolution Petrous Bone Imaging Using Multi-slice Computerized Tomography

Multi-slice computerized tomography (MSCT) is considered to provide superior image quality. We defined a data acquisition protocol for high-resolution (HR) temporal bone imaging using MSCT and assessed its impact on data acquisition and post-processing (PP). The data acquisition protocol was defined in cadaveric phantom studies performed by MSCT and subsequently applied to 38 patients referred for temporal bone assessment. The parameters image quality and diagnostic value of MSCT data were assessed for the cross-sectional source images as well as for 2-dimensional (2D) reformations and 3-dimensional (3D) reconstructions by 3 radiologists by comparison with incremental HR scans of 17 patients with suspected middle ear disorders. The data acquisition protocol yielded HR images with an excellent detail resolution and a comparable image quality of cross-sectional scans and related orthogonal reformations. MSCT achieved higher scores for image quality and diagnostic value (p &lt; 0.001, t-test) than incremental HR CT with regard to both 2D and 3D reconstructions. MSCT improves the image quality of HR cross-sectional scans as well as that of 2D and 3D PP techniques in petrous bone imaging. The radiation exposure of the eye lenses is increased by MSCT as gantry angulation is not yet possible in the helical scan mode.     

Limited CT scanning techniques of the paranasal sinuses

Computerized tomographic (CT) imaging provides detailed information on the paranasal sinuses and is now well established as an alternative to standard radiographs. The planning and safety of surgery to the paranasal sinuses is greatly improved by CT imaging. We describe a new CT protocol comprising a limited coronal and axial scan series, based on our experience with the previously described 'CT-Mini-series'.     

Survey anatomy of the paranasal sinuses in the normal mouse

OBJECTIVE: To provide researchers with a survey atlas of normal paranasal sinus anatomy in the mouse as well as to standardize the reporting of data within the murine nose and sinuses. STUDY DESIGN: Histologic and radiographic study in mice. METHODS: C57BL/6 mice were killed and their heads sectioned in the axial and coronal planes as well as imaged using a small animal micro-computed tomography (CT) scanner. Distinctive regions within the nose and paranasal sinuses were delineated and labeled A to G for identification. RESULTS: Definable regions within the normal murine nose and paranasal sinuses include A) the nasal airway, B) the superior nasal vault, C) the osteomeatal complex, D) the anterior ethmoid sinuses, E) the posterior ethmoid sinuses, F) the true maxillary sinus, and G) the secondary maxillary sinus. Mice also possess discernible sphenoid sinuses. CT scans confirmed the histologic plane of section. CONCLUSIONS: A survey atlas of normal murine sinonasal anatomy shall provide laboratories seeking to use mice in sinus research a reference for beginning their work. As new transgenic and gene knockout mice become available, phenotypic changes in sinonasal architecture can be more easily discerned using such a reference. Defining specific regions (A-G) within the sinuses will standardize the nomenclature used for reporting data.     

鼻窦炎患者鼻窦骨结构变异和鼻窦粘膜异常的CT扫描分析

对109例临床疑为鼻窦炎患者的CT冠状扫描结果进行了分析,鼻窦粘膜异常改变者93例(85.3％),16例粘膜呈正常影像(14.7％),93例鼻窦粘膜异常改变者中,发现鼻窦骨结构变异60例(64.5％)。通过对鼻窦骨结构变异和鼻窦炎情况的观察分析,认为鼻窦骨结构变异可能是鼻窦炎致病因素之一。鼻窦粘膜异常以前组筛窦和上颌窦发生率最高,同时伴有窦口鼻道复合体粘膜异常,支持了鼻窦口引流障碍可以继发鼻窦炎的观点。作者认为采用鼻窦CT冠状扫描对判断鼻窦炎的病因和临床诊断具有重要意义。     

Radiologic diagnosis of inflammatory and tumorous disorders of the paranasal sinuses

In a retrospective study, 158 patients with therapy resistant symptoms of paranasal sinus affections were investigated with conventional tomography, 39 patients in addition underwent computed tomography (CT) examination. From conventional tomography films, inflammatory affections limited to the paranasal sinuses were clearly diagnosed in 99%, and benign tumours in 76%. The dignity of malignant neoplasms was correctly recognized in 100%. CT provided additional information in 10% with regard to bone destruction, in 28% with regard to brain involvement, and in 17% with regard to tumour extension into the orbita. Considering the precise diagnosis and economical factors, conventional tomography is indicated as the primary investigation procedure in the evaluation of inflammatory and benign disease of the paranasal sinuses. CT gives definite additional information in cases of suspected bone destruction and in affections extending beyond the paranasal sinuses because of its more detailed depiction of the paranasal sinus structures.     

Study of ethmoid sinus involvement in multibacillary leprosy

The nasal mucosal involvement in lepromatous leprosy is well recognized. Currently interest has centred around the involvement of paranasal sinuses in leprosy. They act as a reservoir and constant source of reinfection to the nasal mucosa. In the present prospective study 25 untreated patients with multi-bacillary leprosy were included. Clinical examination, computed tomography (CT) scan of paranasal sinuses, ethmoid sinus endoscopy and biopsy were carried out in all patients, to investigate the involvement of the paranasal sinuses in leprosy. Ethmoid sinus involvement was noted in 20 patients on CT scan. Bilateral involvement was more common (65 per cent). Anterior ethmoids were more commonly affected (65 per cent). On ethmoid sinus endoscopy abnormal mucosa was noted in 17 patients (68 per cent). Ethmoid sinus biopsy was confirmative in 16 patients (64 per cent). Statistically significant correlation was found between CT findings, sinus endoscopy and sinus biopsy findings.     

Nasal obstruction in the adult: is CT scan of the sinuses necessary?

OBJECTIVE: To determine whether CT (computerized tomography) scan of the paranasal sinuses is essential in the diagnosis and medical/surgical management of nasal obstruction. DESIGN: One hundred thirteen adult patients with nasal obstruction but without signs of sinusitis who underwent CT examination prior to surgery, were included in the study. RESULTS: Fifty seven percent of the CT scans revealed a variety of abnormal findings. Of the patients with an abnormal CT scan, surgical planning had to be altered in 16 patients due to significant abnormalities found on the CT scans. CONCLUSIONS: We conclude that CT scan of the nose and paranasal sinuses is an effective presurgical planning tool in patients with nasal obstruction.     

Superior turbinate pneumatization in patients with chronic rhinosinusitis: prevalence on paranasal sinus CT

With the availability of high-resolution computed tomography (CT), a great deal of attention has been paid to the anatomy of the paranasal sinuses. But while investigators have focused on the osteomeatal complex and its relation to chronic rhinosinusitis, there has been little discussion of the superior turbinate. Although a few anatomic studies have tried to quantify pneumatization of the superior turbinate, the prevalence of this finding on radiography is not well addressed in the literature. We prospectively studied 100 consecutively presenting patients who underwent coronal CT of the paranasal sinuses (200 sides) for the evaluation of symptoms of chronic rhinosinusitis at an academic tertiary referral center to determine the prevalence of pneumatization of the superior turbinate. We found evidence of pneumatization in 44 of the 200 sides, for a prevalence of 22%. In all, pneumatized superior turbinates were found in 27 patients (27%)-bilaterally in 17 (17%) and unilaterally in 10 (10%).     

Nasal chondromesynchymal hamartoma presenting in an adolescent

Nasal chondromesenchymal hamartoma (NCMH) is extremely uncommon primary benign cartilaginous growth of the nasal and paranasal sinuses. To date, it has been reported almost exclusively in infancy. We report a NCMH in a 16-year-old patient who presented with an asymptomatic, fixed swelling on the left side of the nose approximately 2x2 cm in size. Computed tomography (CT) and magnetic resonance imaging (MRI) of the nose, paranasal sinuses and neck confirmed a heterogeneous, calcified polypoidal mass protruding caudally into the left nasal cavity. After an initial inconclusive incisional biopsy, the patient underwent a complete radical resection, with staged reconstruction of the full nasal defect using septal mucosal flap, conchal cartilage graft and forehead skin flap. Histological examination of the resected specimen confirmed NCMH, which, we believe, had probably been present and undetected for many years. This report greatly extends the age at which NCMH may be entertained as part of the differential diagnosis of cartilaginous lesions of the nose and paranasal sinuses.     

Rationelle CT-Diagnostik vor Operationen an den Nasennebenhöhlen

Movement or metal artefacts as well as the relatively high radiation exposure of both the axial and the coronal scan are disadvantages of computed tomography. A single spiral CT scan with a secondary reformation replacing the second CT scan might solve these problems. The goal of this project was to compare the diagnostic value of primary spiral CT scans of paranasal sinuses with secondary reformations. These were evaluated by ENT surgeons as well as radiologists. We performed axial and coronal spiral-CT's of paranasal sinuses in 80 patients. The secondary coronal and axial reformations were calculated with 2 mm image sections. Although a reduced resolution was observed in the secondary reformations, this did not compromise the detection of important anatomical features. Image deterioration due to artifacts was significantly reduced.     

Correlation between computed tomography and bone single photon emission-computed tomography scintigraphy in patients with chronic rhinosinusitis

BACKGROUND: Computed tomography (CT) has been the imaging study of choicefor evaluating chronic rhinosinusitis (CRS). 99mTc-MDP bone single photon emission-computed tomography (SPECT) has proven useful at identifying inflammation of bone and its use in CRS has been discussed recently. No studies, however, have documented the correlation between these two imaging modalities in CRS. METHODS: A retrospective analysis was performed of 30 patients with CRS who underwent CT and SPECT scan of the paranasal sinuses. Increased radiotracer uptake during SPECT scan was compared with CT findings graded on the Lund-Mackay score (LMS). The findings of the two imaging modalities were compared and evaluated for standard correlative statistics for diagnostic tests. RESULTS: SPECT imaging was abnormal in 25/30 patients, and CT was abnormal in 27/30 patients. Correlation between the two was highest for the ethmoid sinuses at 73.3%. SPECT had a high positive predictive value for mucosal inflammation on CT of 84.1%. Approximately 25% of individual sinuses with a positive SPECT in patients without prior surgery were not positive in corresponding sinuses onl CT. There was a positive correlation between the LMS and the number of SPECT positive sinuses within the same patient (r = 0.486; p = 0.006). CONCLUSION: 99mTc-MDP SPECT scan in patients with CRS is shown to be a useful indicator of bone involvement. The relatively high rate of bone involvement in the absence of mucosal inflammation as seen in this study warrants additional research and the potential need for different therapies than are currently available.     

Sphenoid sinus development in patients with acquired middle ear cholesteatoma

ObjectiveIn this study, we examine the relationship between developmental insufficiency of mastoid air cells and abnormal morphology of the paranasal sinuses in patients with chronic otitis media (COM) and acquired middle ear cholesteatoma (AMEC) using precise image assessment, in order to evaluate whether the anatomical features of paranasal sinuses has any impact on the pathogenesis in COM and AMEC.MethodsA total of 127 patients, including 45 COM patients and 82 AMEC patients, were enrolled for this study. The existence of nasal septal deviation, the existence of paranasal sinus opacification, the modified Lund–Mackay score, the diameters of the paranasal sinuses, the Vidic classification, mastoid development, and cranial size were assessed by CT examination. A further 76 adult patients who underwent high-resolution CT imaging of their skull bone for other diseases were enrolled as the control.ResultsThe AMEC group showed a significantly shorter sphenoid length (P < 0.01) and lower Vidic classification score (P < 0.01) compared to the control group in this study. In addition, we observed that patients with AMEC had less pneumatization of the mastoid air cells compared to the control individuals, and that the sphenoid length of the poor MC score group was significantly shorter than that of the good MC score group.ConclusionOur results suggested that the developmental deficiency in sphenoid length caused by long-standing pediatric rhinosinusitis might indicate the potential of chronic middle ear inflammation in childhood and impact the pneumatization of mastoid air cells. Therefore, chronic rhinosinusitis during the childhood and adolescence might play a role in the pathophysiology of AMEC.     

Ethmomaxillary sinus

Ethmomaxillary sinus is a variation of the posterior ethmoid cells. It is formed by the extension of the posterior ethmoid cells into the maxillary sinus and drains into superior nasal meatus. It is incidentally seen on paranasal sinus computerized tomography (CT) scans. Its prevalence has been reported as 0.7 and 2% in two studies. In this study, paranasal CT scans of 466 patients were investigated for the presence of ethmomaxillary sinus. The patients had paranasal CT with the preliminary diagnoses of septal deviation, chronic inflammatory paranasal sinus disease and nasal turbinate disorders. The ethmomaxillary sinus was present in nine of those patients (1.93%). It was septated in one of them. The CTs were further investigated for other anatomical variations and co-existent mucosal disease of the paranasal sinuses.     

Complementary use of computed tomography and magnetic resonance imaging in assessing skull base lesions.

Twenty-six patients underwent computed tomography (CT) and magnetic resonance imaging (MRI) of skull base lesions at the Cleveland Clinic Foundation. CT provided improved bone detail, documenting invasion of the lamina papyracea, orbital floor, fovea ethmoidalis, cribriform plate, pterygoid plates, hard palate, and skull base. MRI defined invasion of the orbit, dura, brain, and cavernous sinus. Improved soft-tissue-tumor interface was evident on MRI. MRI was superior to CT in determining carotid artery involvement. MRI distinguished between tumor and retained secretions in the paranasal sinuses. Combining radiographic tumor staging reliably predicted surgical findings; however, MRI consistently yielded sufficient diagnostic information and the additional expense of performing two imaging procedures may not be justified.     

鼻腔鼻窦非霍奇金淋巴瘤的CT表现

目的：探讨鼻腔鼻窦非霍奇金淋巴瘤（ＣＨＬ）的ＣＴ影像学特征,方法：对９例经病检确诊为鼻腔鼻窦ＮＨＬ患者的ＣＴ片进行回顾性分析。结果;原发于鼻腔鼻窦的ＮＨＬ在临床上有着典型的恶性特征,但在ＣＴ影像上所表现的骨质破坏,类似于良性病变的骨改建、骨膨胀性改变,而非其他恶性肿瘤那样表现为侵入性骨质破坏;其在鼻腔内形成均匀软组织密度影,常累及下鼻道、下鼻甲;并伴有鼻中隔前份粘膜对称性增厚;结论：原发于鼻腔鼻窦     

Diagnostic imaging of the nose and paranasal sinuses

There are four principal modalities now used by the Radiologist to investigate the nose and paranasal sinuses. These are: plain X-ray, conventional tomography, computerised tomography (CT), and magnetic resonance (MR). Plain X-ray is the initial examination, and is used as a screening procedure before employing one of the tomographic techniques. Conventional pluridirectional tomography has now been superseded by CT scanning, which has the advantage of providing both good bone detail and soft tissue imaging. Since the introduction of magnetic resonance (MR), this technique has replaced CT as the optimum method of showing the extent of soft tissue tumour in the sinuses. The introduction of the paramagnetic contrast agent Gadolinium (Gd DTPA) has improved its accuracy. In the anterior fossa discrimination between cerebral oedema and tumour invasion is better shown, and in the sinuses tumour is more easily identified from retained secretion and inflamed mucosa. The best method currently available to show pathology in the nose and sinuses is a combination of GdMR and CT: the former to identify the soft tissues and the latter to show bone changes.     

腭裂患儿鼻腔和鼻窦的形态学观察

应用组织病理学、ＣＴ扫描、计算机图像处理和三维ＣＴ重建方法观察了８例先天性腭裂患儿鼻腔和鼻窦的形态学改变，发现①８例腭裂患儿中，３例有双侧上颌窦炎，１例双上颌窦和前组筛窦有分泌物潴留，提示咽帆关闭不全可能是腭裂患儿鼻窦炎高发的主要原因；②连续ＣＴ扫描的计算机图像处理，结合三维ＣＴ重建可以准确计算鼻窦的体积，显示鼻窦的形状，为今后深入研究儿童鼻窦的发育和解剖特点提供了一条新路。计算机三维ＣＴ重建可以在冠状、矢状和水平位显示鼻腔和鼻窦占位病变的大小和侵犯范围，对正确诊断鼻部疾病，辅助教学，合理设计手术方法有一定的参考价值。