Comparison of three-dimensional computed tomography with rapid prototype models in the management of coronoid hyperplasia

OBJECTIVES: To compare (1) the accuracy of 3DCT with rapid prototyping (RP) models and (2) their application in the management of coronoid hyperplasia. METHODS: An adult dry skull was used to compare 3DCT and a RP model for accuracy of reproduction; Polymerisation contraction and 17 distances between 27 anatomical points were measured. Two patients with coronoid process hyperplasia were assessed by means of 3DCT and plastic models. RESULTS: Differences in measurements with the RP model and the dried skull were smaller than those with 3DCT (P=0.04). Polymerisation contraction was greater than the errors in reproduction with the RP model and approximately equal to those with the 3DCT. The coronoid process was thick and prominent in the patients with coronoid process hyperplasia and the small space and early contact between zygomatic arch and the coronoid process demonstrated. The plastic model duplicated the exostosis of the inner surface of the malar bone facing the concavity of the elongated process. The coronoid process had an anterior tilt in one case. CONCLUSION: The plastic model duplicated the relationship between the maxillofacial deformity and the coronoid process with tolerable accuracy. Trismus may be due to the direction as well as the length of the enlarged coronoid process.     

Comparison of ultrasonography with submentovertex films and computed tomography scan in the diagnosis of zygomatic arch fractures

Objectives

The aim of this study was to compare ultrasonography with CT scan and submentovertex films in the visualization of zygomatic arch fractures.

Methods

17 patients, 10 men and 7 women, with suspected fracture of the zygomatic arch were studied. The data from CT and plain films were compared with the ultrasonographic findings (Aloka 3500 (Tokyo, Japan) ultrasound equipment with a 7.5 MHz transducer). The probe was situated over the fractured arch transversely to evaluate its whole length. All of the sonograms were taken and interpreted by the same sonologist, who was not aware of the results of the CT and the plain films.

Results

Ultrasound was accurate in assessing the fractured arches with sensitivity of 88.2% (15 of the 17 patients, with two false negatives) and specificity of 100% (no false positives).

Conclusion

Ultrasound is accurate in the visualization of zygomatic arch fractures and can be used as an adjunct to plain films to reduce the overall radiation exposure.     

Examination of incident angle for photography of axial projection of zygomatic arch

In axial zygomatic arch roentgenography, the radiographic angle is determined by taking account of the light field-projected image. However, this method is technically difficult and has poor reproducibility because the body target surface is uncertain at the time of positioning. Therefore, we obtained 3D-CT images from CT examinations of the facial or paranasal sinus, and we assessed the X-ray beam angle where the zygomatic arch is most clearly delineated in terms of sex and age by taking the acanthion-meatal line (France horizon) as the reference. The zygomatic arch was most clearly seen when the X-ray beam angle was perpendicular to the acanthion-meatal line. Excellent images were obtained, and reproducibility of the images was improved using the radiographic technique based on this result.     

Conventional radiology and computed tomography in facial fractures

The possibilities and limitations of conventional radiography and CT in detecting maxillo-facial fractures are shown both experimentally and in a clinical setting. In 36 patients examined by both methods after maxillo-facial trauma, CT and conventional radiography (including pluridirectional tomography) proved to be equal in detecting fractures of the orbital roof, the anterior wall of the frontal sinus, the nasal bone and the pterygoid process. CT is inferior to conventional radiography in fracture of the orbital floor, the frontal base of the skull, the hard plate and the zygomatic arch. CT is superior to conventional radiography in fractures of the medial and lateral wall of the orbit, the posterior wall of the frontal sinus, the posterior, medial and anterior wall of the maxillary sinus as well as the zygomatic bone.     

The radiological features of craniofacial neurofibromatosis.

Three cases of neurofibromatosis are reported showing a wide spectrum of roentgen abnormalities affecting the skull and facial bones. One case had macrocrania and multiple calvarial defects; enlargement of the sella turcica and middle cranial fossa was also present. All the three cases had orbital changes either in the form of enlargement, reduced anteroposterior width or loss of bony outlines with an appearance of emptiness. The other two cases showed predominantly facial involvement with hypoplasia of the mandibular body and ramus, abnormal coronoid process, zygomatic arch, hypoplastic maxilla, cystic mandible with abnormal dentition and absence of the osseous external auditory meatus. Intra-orbital calcification was present in one case. The radiological projections required to evaluate such cases are discussed. The 20 degrees occipito-mental view has been found extremely useful and is recommended.     

Roentgen diagnosis of midfacial fractures

The course and configuration of typical maxillofacial fractures (type Le Fort I-III) and lateral maxillary fractures including the zygomatic arch were reconstructed in detail by application of barium paste on a bony skull and radiographs in standard projections were performed and evaluated. It was obvious from the resulting radiographs that for most maxillofacial fractures a half axial or Water's view was most helpful. Lateral views only give additional information when there is a considerable degree of dislocation of fragments. Comparison with a pediatric skull of 8 years of age demonstrated that fractures of the zygomatic arch in this age group cannot be demonstrated by the typical submento-vertical view, but are shown on a Towne projection. The radiographic appearance of important maxillofacial fractures is demonstrated. The necessity of further studies in cases where reconstructive surgery appears necessary is discussed and CT rather then conventional tomography is advocated.     

The value of three-dimensional computed tomography in diagnosis and management of Jacob's disease

This study reports a case of Jacob's disease characterized with limited mouth opening due to bilateral coronoid hyperplasia forming pseudojoints with zygomatic arches. Magnetic resonance (MR) examination of temporomandibular joint (TMJ) is usually the imaging method chosen in patients with such symptoms. However, the coronoid processes can not be displayed because they are not included in field of view in MR imaging of TMJ. For that reason, these patients may be treated for a misdiagnosis of TMJ disorders. In this study, the aetiology and diagnostic methods of Jacob's disease, the pre-operative/post-operative role of three-dimensional computed tomography and some measurements used in diagnosis were evaluated.     

不同分型系统评估恐怖三联征中尺骨冠突骨折的特点及信度分析

目的 使用3种尺骨冠突骨折分型系统评估恐怖三联征(TTI)中尺骨冠突骨折类型,探讨TTI中尺骨冠突骨折的特点及各尺骨冠突骨折分型系统的可信度.方法 采用回顾性病例系列研究分析2013年1月至2020年10月福建医科大学附属第一医院收治的43例典型TTI患者的CT资料,其中男26例,女17例;年龄18 ～ 88岁[(41...     

Examination of axial zygomatic arch radiographs using the bisector method

An axial radiograph of the zygomatic arch is taken in cases of patients with facial traumatic injury. Maintaining the patient's head in the retroflex position to take such axial radiographs is sometimes difficult because of medical conditions. In addition, since different positioning techniques for retroflexion are used by radiological technologists, the visibility of the zygomatic arch was poorly in reproduced. We contrived a novel technique for use in taking a zygomatic arch radiograph. We call it the "bisector method," and it does not require the retroflex position. We can take a zygomatic arch radiograph equal in quality to conventional axial radiographs (retroflex position) by exposing X-rays perpendicularly to the bisector of the angle between the casette and the zygomatic arch. This bisector method is relatively easy in that it does not require either the retroflex position or the expertise of a radiological technologist.     

Nodular fasciitis: a case at the level of the zygomatic arch

The case of a man who developed a nodular fasciitis at the zygomatic arch after a minor facial trauma is presented. Nodular fasciitis is a benign fibroblastic proliferation with unknown etiology; in a number of cases, a recent trauma is mentioned as the triggering cause. The CT characteristics are discussed and the recent literature is reviewed.     

Anatomic, clinical, surgical, and radiographic correlation of the zygomatic complex fracture.

Understanding the mechanisms by which clinical signs and symptoms are produced is a prerequisite to the correct appreciation of radiographic features. Radiographs of facial trauma are no different in this respect. This paper describes the specific clinical findings associated with each displaced bony fragment of the zygomatic complex fracture. Limitation of jaw movement and flattening of the cheek are produced by depressed fractures of the temporal process or zygomatic arch; unilateral epistaxis is a result of fractures of the zygomatic process of the maxilla or the floor of the orbit; paresthesia or anesthesia of the cheek results from fractures of the infraorbital process or orbital floor; unequal pupil heights is associated with fracture of the frontal process; and decreased extraocular muscle function with diplopia is caused by fractures of the orbital process, frontal process, or orbital floor. The clinical and radiographic findings are correlated with surgical management.     

Aneurysmal bone cyst of the coronoid process of the mandible.

A rare case of an aneurysmal bone cyst (ABC) involving the right coronoid process of the mandible in a 12-year-old girl is presented. The characteristic features with fluid-fluid levels within the lesion observed on Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) was helpful in the preoperative diagnosis.     

Bilateral coronoid hyperplasia in two brothers

Coronoid hyperplasia is a rare condition of unknown aetiology that can occur in both unilateral and bilateral forms. Without radiographic investigation the diagnosis is often missed. Researchers have postulated a familial form of inheritance. This study reports the occurrence of coronoid hyperplasia in two brothers. The parents were unaffected and there are no other siblings. The diagnosis was confirmed with the aid of panoramic radiographs and axial computed tomographic scans with para-sagittal reconstructions which demonstrated enlargement of the coronoid processes and in one case impingement against the zygomatic bone. One brother was successfully treated with a unilateral intra-oral coronoidectomy whilst the other was unsuccessfully treated with a bilateral intra-oral coronoidectomy.     

Zygomatic air cell defect (ZACD). Prevalence and characteristics in a dental clinic outpatient population.

OBJECTIVES: To determine the prevalence and characteristics of zygomatic air cell defect (ZACD) among a general dental clinic population. METHODS: The panoramic radiographs of 2734 dental clinic outpatients were examined for the presence of ZACD. ZACD was defined as a nonexpansile, nondestructive cyst-like radiolucency in the zygomatic process of the temporal bone which appears similar to the mastoid air cells and which does not extend further anteriorly than the zygomaticotemporal suture. RESULTS: ZACD was found in 40 patients (1.5%) with a mean age of 49.6 (s.d. 18.0) years. Twenty cases (50%) each occurred in males and females. Meta-analysis of three large case series comprising 4579 patients revealed a total of 76 cases of ZACD (1.7% prevalence) occurring over an age range of 15-83 years. Thirty-four (44.7%) occurred in males while 42 (55.3%) occurred in females. Bilateral ZACD were found in 17 patients (22.4%). CONCLUSIONS: ZACD is not a rare anatomical variant, and clinicians planning eminectomy or other surgical procedures involving the zygomatic arch are advised to obtain appropriate presurgical imaging studies to avoid the need for creative intra-operative reconstruction.     

CAD-CAM construction of an auricular template for craniofacial implant positioning: a novel approach to diagnosis

A novel approach to the diagnosis of bone available for craniofacial implant positioning is discussed in a case that required ear ablation for tumor removal. A mirrored volume of the healthy ear was rapidly prototyped for a clinical trial in an appropriate position relative to the patient's face. Three ideal positions for the implant were chosen in the inner of the volume of the mirrored ear. The same positions were transferred to a diagnostic template that was rapidly prototyped with a positioning arm extending to the zygomatic arch. Computed tomography (CT) revealed errors in the planning of the implant position and, as a clinical consequence, an implant site was excluded from surgical planning. A virtual elaboration for maxillofacial implant positioning was used to define the correct implant site in relation to the available bone, and two craniofacial implants were correctly positioned in the temporal bone.     

Melnick-Needles syndrome: radiographic alterations in the mandible

After the adventitious finding of bilateral loculations in the mandibular rami and erosion of the coronoid processes of the mandible of a patient with Melnick-Needles syndrome (osteodysplasty), the jaws of four other individuals with the same disorder were examined for similar changes. The coronoid process of the mandible was grossly hypoplastic in all patients, and the rami were markedly abbreviated. In four of the five patients the angle was rounded. In three of five patients, loculations of unknown nature were found in the mandibular rami. Several patients exhibited impacted molar teeth.     

16层螺旋CT在茎突测量中的应用

目的探讨16层螺旋CT在茎突测量中的应用价值。方法对120例受检者进行16层螺旋CT扫描,在工作站上用VR,MIP及MPR法测量茎突长度、内倾角,并直接测量前倾角及通过测量茎突与颧弓夹角间接测量前倾角。结果VR图像上可以准确测量茎突前倾角（22．56±2．32°）,并间接测得前倾角23．11±2．56°,内倾角为21．89±4．82°。VR,MIP2D工具及3D工具均可测量茎突长度,2D工具与3D工具测量结果有显著差异。MPR图像测得茎突长度为22．98±2．83cm。VR及MIP3D工具与MPR测得茎突长度无显著性差异。结论16层螺旋CT扫描可以准确测量茎突长度及倾斜角度,测量茎突长度以VR3D工具最为实用,而间接法测量茎突前倾角更为简便。     

The value of magnetic resonance imaging in the diagnosis of orbital floor fractures

The value of MRI in the diagnosis of acute orbital floor fractures has not been clearly defined. We therefore compared MR findings with CT findings in patients with orbital trauma. In 30 patients with isolated orbital trauma both coronal CT and coronal MRI were used to examine the orbits and the adjacent paranasal sinuses. Visualization of anatomical landmarks, the kind and extent of traumatic lesions, as well as artifacts were scored. The scores were compared using the Wilcoxon matched-pairs signed-rank test. Interexamination agreement between the two methods was calculated using a kappa analysis. All examinations had diagnostic quality: 30 fractures of the orbital floor (9 right and 21 left orbital floor fractures) were identified. In addition, CT showed fractures of the medial orbital wall in 19 patients (63.3%), of the lateral wall in 10 patients (33.3%), of the zygomatic arch in 2 patients (6.7%), and of the maxillary sinus in 4 patients (13.3%). Soft tissue herniation was shown in 13 patients (inferior rectus muscle twice, orbital fat in 11 cases). Magnetic resonance imaging demonstrated soft tissue herniation in 21 patients: muscle in 4, orbital fat in 17 cases. Magnetic resonance imaging is able to demonstrate orbital floor fractures as sensitively as CT, but CT is superior to MRI in showing small and associated fractures; therefore, CT remains in orbital fractures the imaging modality of choice. Magnetic resonance imaging is superior to CT in showing soft tissue herniations; therefore, MRI may have a role as an adjunct to CT if soft tissue entrapment remains unclear.     

Aneurysmal bone cyst of the zygomatic arch: a case report

We describe a case of an aneurysmal bone cyst originating from the zygomatic arch, which, according to the literature, is an extremely rare location. In the preoperative diagnosis the characteristic radiological signs of the high-quality computed tomography and magnetic resonance examinations were the cornerstones. Treatment was successful total excision. Careful diagnostic workup and multidisciplinary approach (head and neck surgeon, radiologist, and pathologist) should be utilized to successfully diagnose and to treat this rare pathology.