High-resolution computed tomography of the osseous temporomandibular joint. Some normal and abnormal appearances

A standardized CT procedure for examination of the temporomandibular joint (TMJ) with axial and coronal scanning as well as reformatted coronal and sagittal sections, was performed on 32 adults. These included subjects with normal TMJ and patients suffering from muscular dysfunction/disc displacement, arthrosis or rheumatoid arthritis. Some normal CT appearances simulating disease were presented. Axial CT scanning appeared to be the most useful method for demonstrating osseous abnormalities of the TMJ. The diagnostic information was occasionally supplemented by the coronal scanning, which may be difficult to perform on patients with neck stiffness. Reformatted coronal or sagittal sections mostly confirmed TMJ abnormality and supplemented the findings at axial scans in about one third of the patients.     

The pneumatic spaces of the temporal bone: relationship to the temporomandibular joint.

OBJECTIVES: To assess the topographic relationship between the pneumatic spaces of the temporal bone and the temporomandibular joint (TMJ) using high-resolution CT. METHODS: Findings from 100 consecutive patients who had undergone high-resolution axial CT of the base of the skull were reviewed on a digital imaging workstation. Additional multiplanar reformatted images were created in the sagittal and coronal planes through the TMJ. The extension of the pneumatic spaces of the temporal bone and their relation to the TMJ were determined on both sides. RESULTS: The extent of pneumatisation of the temporal bone varied considerably. The roof of the TMJ fossa was pneumatised in 51 patients. The articular eminence contained air spaces in 12 patients, the root of the zygomatic process in five patients. Air cells in the peritubal area extended into the medial wall of the glenoid fossa 53 patients. In approximately 25% the extent of pneumatisation showed marked asymmetry. CONCLUSIONS: Pneumatisation of the temporal bone frequently extends close to the TMJ. Knowledge of these air spaces is helpful for the interpretation of imaging studies such as panoramic radiographs and to understand the spread of pathological processes into the joint.     

Osseous temporomandibular joint abnormalities in rheumatic disease. Computed tomography versus hypocycloidal tomography

Computed tomography (CT) of the temporomandibular joint (TMJ) was compared with hypocycloidal tomography in 30 joints of 15 adults with rheumatic disease. CT included 1.5 mm thick axial scans (at 1.0 mm intervals) with reformatted oblique sagittal and oblique coronal sections. Multisection (at 2.0 mm intervals) tomography included oblique sagittal and occasionally, oblique coronal sections. CT demonstrated bone abnormalities in 21 and tomography in 20 joints, indicating high agreement between the imaging modalities regarding number of abnormal TMJs. Bone structures were, however, better visualized by multiplanar CT due to superior contrast and spatial resolution particularly in the most lateral and medial parts of the joint, indicating superiority of CT for depicting subtle bony TMJ abnormalities in patients with rheumatic disease.     

牙颌专用CT的颞颌关节成像技术

目的：探讨牙颌专用CT的颞颌关节成像技术及临床应用价值。材料和方法：对162例疑有颞颌关节病的患者行牙颌专用CT的颞颌关节检查,对感兴趣区影像重建,获取临床常用的轴位、冠状位、矢状位外,增加平行于髁状突长轴的斜位、垂直于髁状突长轴的斜位及双侧髁状突曲面重建影像分析其表现并评估其应用价值。结果：162例受试者均获满意的重建影像。平行于髁状突长轴的斜位和垂直于髁状突长轴的斜位,显示了颞颌关节的真实形态。双侧髁状突曲面成像,将水平角不在一条直线上的双侧髁状突长轴或短轴层面,重建在一幅影像内,方便了双侧髁状突相同体位影像的对比观察。结论：牙颌专用CT成像软件系统可以对颞颌关节骨性结构行多种体位、角度的重建及径值的测量。     

Incomplete intertrochanteric fractures: imaging features and clinical management

PURPOSE: To present the imaging findings and treatment options for incomplete intertrochanteric fractures. MATERIALS AND METHODS: Among 31 patients with the magnetic resonance (MR) imaging diagnosis of incomplete intertrochanteric fracture, 30 also underwent radiography. MR and radiographic findings were compared. Note was made of fracture length and extent as depicted on the coronal and axial MR images, treatment (surgical vs conservative), and follow-up. RESULTS: Correlation between radiographic and MR findings was poor. Incomplete intertrochanteric fracture was the prospective radiographic diagnosis in only one case. Fracture in 18 patients was treated surgically and in 13 was managed conservatively. In both groups, the average age of the patients and length of the fractures and the percentage of separate fractures involving the greater trochanter and crossing the midline of the femur in the axial plane were the same. Fractures crossed the midline in the coronal plane in 50% of the surgical group but in only 23% of the nonsurgical group. Average time from injury to ambulation was 2 days less in the surgical group, but no difference in functional status was found subjectively between the two groups at clinical follow-up. CONCLUSION: Incomplete intertrochanteric fractures are a previously unrecognized subset of intertrochanteric fractures that are diagnosed unequivocally only with MR imaging.     

Subtle pathology detection with multidetector row coronal and sagittal CT reformations in acute head trauma

We sought to analyze retrospectively the advantages of coronal and sagittal reformations obtained with multidetector row computed tomography (CT) in patients with acute head trauma. Multidetector 16-section CT was performed in 200 patients (110 male and 90 female; age range, 3–87 years; mean age, 45 years) with acute head trauma. Scans were performed sequentially, and axial 5-mm-thick slices were obtained from base of skull to vertex. The source data set was reformatted in coronal and sagittal planes, with 2-mm-thick sections at 2-mm intervals. Images were analyzed retrospectively by two independent, blinded readers. The final diagnosis was determined by clinical follow-up. CT imaging abnormalities were detected in 55 out of 200 patients who were scanned for head trauma. Acute traumatic intracranial abnormality was detected on axial scans in 45 patients. Subtle findings were confirmed on coronal and sagittal CT reformations in ten cases, and these were undetected initially on axial CT. Coronal and sagittal reformations confirmed subtle findings in 18.2% (10/55) of the cases (P = 0.001). Indeterminate neuroimaging findings confirmed by coronal and sagittal CT head reformations include tentorial and interhemispheric fissure subdural hemorrhage, subarachnoid hemorrhage, and inferior frontal and temporal lobe contusions. Coronal and sagittal CT head reformations improve the sensitivity and diagnostic confidence in the clinical setting of acute trauma. Overall, coronal and sagittal reformations improved diagnostic confidence and interobserver agreement over axial images alone for visualization of normal structures and in the diagnosis of acute abnormality.     

Preoperative staging accuracy of multidetector row computed tomography for extrahepatic bile duct carcinoma

PURPOSE: This study sought to evaluate the accuracy of multidetector computed tomography (MDCT) for preoperative staging of extrahepatic bile duct (EHD) carcinoma and to assess the value of coronal reformations from isotropic voxels. MATERIALS AND METHODS: Thirty patients with surgically proven EHD cancer underwent dynamic MDCT with coronal reformation. Two experienced radiologists independently evaluated contrast-enhanced dynamic transverse CT images (axial approach) and combined transverse and coronal images (combined approach). The radial extent (TNM staging) and the vertical extent of tumors were assessed and correlated with pathological findings of surgical specimen. RESULTS: All of primary tumors were detected by axial and combined CT imaging (100%). Overall accuracy of the T staging was 73% (22/30) with axial and 77% (23/30) with combined CT imaging (P>0.05). The accuracy of N staging was 57% (17/30) with axial and 63% (19/30) with combined CT imaging (P>0.05). The accuracy of M staging was 97% (29/30) with both axial and combined CT imaging.Upper margin accuracy was 97% (29/30) for axial and 100% for combined CT imaging (P>0.05), whereas that of the lower margin was 90% (27/30) for axial and 93% (28/30) for combined CT imaging (P>0.05). CONCLUSIONS: Multidetector computed tomography was sufficiently accurate for evaluating the vertical extents, but radial extents of EHD cancer. The addition of coronal reformatted images did not improve the accuracy for staging of EHD cancer.     

Normal and abnormal temporomandibular joint: MR imaging with surface coil

The normal temporomandibular joint (TMJ) was evaluated using magnetic resonance (MR) imaging with a surface coil in five subjects and compared with the abnormal joint in 37 patients (aged 14-59 years; total joints studied, 76). Multisection 3-mm-thick sagittal, coronal, and axial images were obtained with a 1.5-T MR system and 6.5-cm-diameter surface coil using both partial saturation and spin-echo sequences (TR = 1,000 msec, TE = 20 or 25 msec). A comparison with arthrography (n = 13 joints), computed tomography (CT) (n = 11), and surgical (n = 5) findings demonstrated that MR imaging with a surface coil provided an accurate depiction of both normal and abnormal TMJs. MR provided information about meniscal position, morphology, and histology that was not available with either arthrography or CT alone. The imaging potential of MR and its noninvasive characteristics warrant priority for further examination of MR as a useful modality in the diagnosis of TMJ pain and dysfunction.     

Predictability of a three-dimensional planning system for oral implant surgery.

OBJECTIVES: To compare 2D CT alone with 2D + 3D reconstruction for pre-operative planning of implant placement. METHODS: Spiral CT scans of 33 consecutive patients were used for both reformatted 2D and 3D computer-assisted planning. The number, site and size of implants and the occurrence of anatomical complications during planning and implant placement were statistically compared using the percentage agreement and the Kendall's correlation coefficients (tau). Although planning was performed in 33 patients, implants were only placed in 21 patients. In 11 patients surgery was based on 2D + 3D imaging and in ten patients on 2D planning. RESULTS: Agreement between planning and placement of implants was highly significant for the implant sites selected. For 2D based planning and placement, agreement reached 68% (tau = 0.94). For 2D + 3D based planning and placement, agreement attained 73% (tau = 0.89). For planning and placement of implant size based on 2D images, agreement was 31% and not significant (tau = 0.23). When based on 2D + 3D images, agreement for implant size was 44% (tau = 0.5). Agreement was not significant for anatomical complications: 69% for 2D planning and 71% for 2D + 3D planning (tau = 0.24 for 2D and tau = 0.21 for 2D + 3D). CONCLUSIONS: The 3D planning system is a reliable tool for pre-operative assessment of implant placement. Both 2D and 2D + 3D planning have a good predictability for the number and site of the implants but less so for anatomical complications. However, the 2D + 3D planning provides a better pre-operative assessment of implant size.     

Coronal reformations of volumetric expiratory high-resolution CT of the lung

OBJECTIVE: The purposes of this study were to evaluate the quality of coronal reformatted images obtained from volumetric expiratory high-resolution CT imaging and to compare coronal and axial images with regard to their usefulness in detecting and characterizing air trapping. SUBJECTS AND METHODS. We studied 40 consecutive patients with known or suspected diffuse lung diseases with airway abnormalities who underwent volumetric expiratory high-resolution CT between May and July 2003. Respiratory motion artifacts were evaluated at upper, middle, and lower lung areas. Cardiac motion, beam-hardening, and other artifacts were evaluated throughout the lung fields. Detectability, clarity of borders, size, distribution, and extent of air trapping were compared on axial versus coronal end-expiratory high-resolution CT images. RESULTS: Respiratory motion artifacts were either imperceptible or not diagnostically limiting in all patients except three (7%) with diagnostically limiting image degradation at lower lung areas. Other diagnostically limiting image degradation was caused by beam-hardening artifacts in two patients (5%) and by quantum noise in two other patients (5%). The borders of air trapping were more clearly identified on coronal images than on axial images (grade 1 [vague], nine vs three; grade 2 [partially clear], 23 vs 21; grade 3 [completely clear], eight vs 16; median, two vs two; p = 0.001). The coronal reformatted images were as informative as axial images for detecting and assessing the classification and extent of air trapping. CONCLUSION: Coronal reformations of volumetric expiratory high-resolution CT scans were acceptable in image quality and provided additional value by affording clearer visualization of the borders of air trapping than was found in contiguous axial images.     

Using CT to localize side and level of vocal cord paralysis

OBJECTIVE: The purpose of our study was to assess the relative accuracy of imaging findings related to peripheral recurrent nerve paralysis on axial CT studies of the neck. Also assessed were imaging findings of a central vagal neuropathy. MATERIALS AND METHODS: We retrospectively identified 40 patients who had clinically diagnosed vocal cord paralysis and had undergone CT. Eight imaging signs of vocal cord paralysis were assessed, and an imaging distinction between a central or peripheral vagal neuropathy was made by evaluating asymmetric dilatation of the oropharynx with thinning of the constrictor muscles. In two patients, we studied the use of reformatted coronal images from a multidetector CT scanner. RESULTS: For unilateral vocal cord paralysis, the most sensitive imaging findings were ipsilateral pyriform sinus dilatation, medial positioning and thickening of the ipsilateral aryepiglottic fold, and ipsilateral laryngeal ventricle dilatation. In two patients, coronal reformatted images aided the diagnosis by better showing flattening of the subglottic arch. Imaging findings allowed localization of a central vagal neuropathy in four patients. CONCLUSION: Three reliable imaging findings associated with vocal cord paralysis were identified on routine axial CT studies: ipsilateral pyriform sinus dilatation, medial positioning and thickening of the ipsilateral aryepiglottic fold, and ipsilateral laryngeal ventricle dilatation. Coronal reformatted images of the larynx may be helpful, but they are not necessary in 95% of patients. Ipsilateral pharyngeal constrictor muscle atrophy is a helpful imaging finding to localize a more central vagal neuropathy. Our findings can aid radiologists in identifying peripheral and central vagal neuropathy in patients who present for CT of the neck who have a normal voice and are without a history suggestive of a vagal problem.     

Correlation between the disc status in MRI and the different types of traumatic temporomandibular joint ankylosis

Objectives:

We aimed to investigate the correlation between the disc status in MRI and the different types of traumatic temporomandibular joint (TMJ) ankylosis.

Methods:

51 consecutive patients (69 joints), diagnosed with traumatic TMJ ankylosis with a residual condyle (Types A2 and A3), were included in this study. All patients had pre-operative MRI, which was reviewed to determine the disc shape, length and position. The results were compared using the Mann–Whitney test.

Results:

There were 37 joints of Type A2 ankylosis and 32 joints of Type A3. All joints of Type A2 and 27 joints of Type A3 (84.4%) definitely had a discernible disc, while 5 joints of Type A3 had no discernible discs. Among the discernible discs, the lateral disc of Type A2 and the whole disc of Type A3 had severe deformity, while the medial disc of Type A2 had mild deformity. The mean (standard deviation) disc length was 10.88 (1.19) mm in Type A2, but 7.50 (0.82) mm in Type A3. There was a significant difference between Types A2 and A3 (p < 0.05). As for the disc position, the intermediate position was found in all joints.

Conclusions:

There is a correlation between the disc status and the different types of traumatic TMJ ankylosis. Therefore, MRI examination is needed to help treatment planning and predict post-operative TMJ function.     

Radiographic examination of the temporomandibular joint using cone beam computed tomography

Cone beam CT (CBCT) is a new technique for maxillofacial imaging. We describe a reconstruction technique for radiographic examination of the temporomandibular joint (TMJ) using CBCT, and we further present four cases where the technique was employed. The technique provides a complete radiographic investigation of the bony components of the TMJ. The reconstructed images are of high diagnostic quality. The examination time is shorter and the patient dose is lower than that with conventional CT. It may therefore be considered as the imaging technique of choice when investigation of bony changes of the TMJ is the task at hand.     

颞下颌关节区滑膜软骨瘤病的CT诊断

目的探讨颞下颌关节区滑膜软骨瘤病在CT上的表现特点.资料与方法搜集9例主诉为单侧颞下颌关节区肿胀患者的CT轴位和冠状位扫描,并对其CT表现进行评价.所有病例均经关节镜或手术病理证实为滑膜软骨瘤病.结果颞下颌关节滑膜软骨瘤病的CT表现为:(1)关节区软组织肿大(n=8);(2)病变内有散在钙化小体(n=8);(3)关节间隙增宽(n=4);(4)下颌髁突骨质异常改变(n=3);(5)颞骨关节面骨质异常改变(n=6),其中CT表现为颞骨关节面骨质硬化者4例,颞骨关节面骨质吸收者3例,颞骨关节面骨质变薄者1例.1例CT检查显示滑膜软骨瘤病向上经颞骨关节面侵犯颅内(大脑颞叶脑膜).结论颞下颌关节滑膜软骨瘤病的CT表现以该区软组织肿胀伴散在的钙化小体和周围骨质受侵犯为特征.后者可以引起中颅窝底的破坏和颅内侵犯,进而影响病变的预后.     

螺旋CT后处理技术在胫骨平台骨折中的应用

目的:探讨螺旋CT多平面重组(MPVR)和表面遮盖显示(SSD)在胫骨平台骨折中的应用价值。方法: 32例胫骨平台骨折经X线平片、CT扫描后MPVR和SSD后处理,对骨折进行分型,评估骨折程度,选择合适的治 疗方案。结果:32例经MPVR重建后均能清晰地显示各种骨折,可以直接测量骨折劈裂和塌陷的大小。SSD能准 确评估骨折劈裂的方向和塌陷的面积。27例行手术治疗,手术入路根据SSD来确定,手术结果证实了SSD和 MPVR显示的骨折情况。结论:螺旋CT的MPVR和SSD重建有助于胫骨平台骨折碎片的立体定位和正确分型, 对手术方案的制定有重要意义。     

Kartagener综合征的影像诊断（附6例分析及文献复习）

目的探讨Kartagener综合征的影像特征及诊断价值。方法报道Kartagener综合征6例,全部病例均摄有胸部及副鼻窦X线平片,均行胸部CT平扫及副鼻窦横断、冠状CT扫描,1例行HRCT扫描并对影像表现进行了回顾性分析。结果所有患者的胸腔及腹腔内脏完全转位,胸片见“右位心”并伴有支气管扩张症（6例X线平片均可诊断为支扩,其中1例HRCT显示“印戒”征及“轨道”征）。全部病例均可见上颌窦炎,其中1例伴有筛窦炎。结论影像学表现是诊断kartagener的主要依据。     

CT and MRI of spine and sacroiliac involvement in spondyloarthropathy

OBJECTIVE: Spondyloarthropathies are rheumatoid diseases that predominantly affect the axial skeleton, causing pain, stiffness, and ankylosis. The aims of this article are to illustrate the different stages of the diseases from early inflammatory involvement to ankylosis using CT and MRI and to discuss the role of imaging in the management of affected patients. CONCLUSION: CT and MRI are the most sensitive techniques in the detection of axial involvement, permitting earlier diagnosis and optimized treatment.     

Computerized tomography in the study of the diabetic kidney

PURPOSE: We investigated whether any morphometric or densitometric changes are detectable in the kidneys of type 2 diabetic patients. MATERIAL AND METHODS: We retrospectively reviewed the CT findings of 40 diabetic patients and of 20 non-diabetics (the control group) submitted to triphasic helical CT for different abdominal conditions. The type 2 diabetic patients were 23 men and 17 women, mean age 62 years, while the nondiabetic controls were 12 men and 8 women, mean age 58 years. All the CT images were analyzed using the Multiplanar Reconstruction (MPR) software. We classified the diabetic patients as either nephropathic or non-nephropathic based on laboratory signs of renal disease, and divided them into three groups based on the duration of their diabetes (0-5 years, 5-10 years, > 10 years). We evaluated morphometric features, such as the presence of parenchymal or vascular calcifications, axial and coronal renal diameters, coronal renal area, and corticomedullary ratio, and densitometric and functional features, such as unenhanced renal density, cortical and medullary density in the arterial phase, parenchymal density in the nephrographic phase, and contrast elimination. We also compared the results in our subgroups of patients with those in the controls. RESULTS: Both renal diameters on axial sections and cortical density in the arterial phase were significantly lower in the nephropathic group (p < 0.05) than in nonnephropathic patients and controls. The patients with shorter duration of their diabetes had significantly greater axial diameters (p < 0.05); a longer-standing disease correlated significantly (p < 0.05) with smaller axial diameters of kidneys and lower cortical density in the arterial phase. No significant correlation was found for any other parameter. CONCLUSIONS: Renal diameters on axial and coronal sections and cortical density in the arterial phase can be useful indices of early nephropathy in diabetic patients. Further studies are warranted to make these findings suitable for use in clinical practice.     

MR imaging of the nasopharynx and floor of the middle cranial fossa. Part II. Malignant tumors

The intracranial extension of tumors of the nasopharynx and related spaces presents a difficult imaging problem. Unlike computed tomography (CT) scans, magnetic resonance (MR) images are not limited by beam-hardening artifacts from bone or dental amalgam. Forty-six patients with malignant tumors of the nasopharynx and related spaces affecting the skull base underwent MR imaging. MR images were obtained with a 0.3-T permanent-magnet imaging system in axial, sagittal, and coronal planes. MR findings were compared with clinical records, plain radiographs, CT scans, and pathologic correlates when available. MR imaging could demonstrate neoplastic invasion of the bone of the floor of the middle cranial fossa and the vital soft-tissue structures related to it as well as or better than CT. Tumor extension was viewed directly as a continuous mass or indirectly by marrow replacement or displacement of normal structures. Specific anatomic routes through which tumors extend from the nasopharynx to the middle cranial fossa were inferred from MR findings.     

胸肋锁骨肥厚综合征临床影像学诊断

目的探讨胸肋锁骨肥厚综合征的影像学诊断与鉴别诊断。资料与方法回顾性分析6例患者的X线平片和CT平扫资料。6例中,3例行工作站图像后处理,3例行单光子计算机体层(SPECT)扫描。结果6例均为双侧性胸-肋-锁骨区受累骨增粗,骨、骨髓腔及肋软骨密度增高。相邻关节间隙消失,呈骨性融合。CT见右侧第1肋软骨处假骨折线。SPECT扫描示胸锁关节区双侧较对称的放射性核素浓聚。结论胸肋锁骨肥厚综合征具有较典型的影像学特征,结合临床可做出正确诊断。CT成像在显示受累骨骨皮质、髓腔、韧带骨化、关节骨性强直等方面的改变优于X线平片和SPECT。