Yu Q

Carotid artery and jugular vein invasion of oral-maxillofacial and neck malignant tumors: diagnostic value of computed tomography

OBJECTIVE This study aimed to disclose the diagnostic value of computed tomography (CT) images in detecting carotid artery and jugular vein invasion by oral-maxillofacial and neck malignant tumors. Study design Forty-three patients (44 tumors) who had had enhanced CT examination before surgical treatment of oral-maxillofacial and neck malignant tumors were evaluated. The CT manifestations of all tumors were retrospectively compared with the surgical findings. RESULTS Surgical findings recorded that the oral-maxillofacial and neck tumors adhered to 11 of 44 common carotid arteries (CCA) or internal carotid arteries (ICA) and 25 of 44 jugular veins (JV). The abnormal CT manifestations of the 44 oral-maxillofacial and neck malignant tumors with CCA, ICA, and JV involvement consisted of 6 types: type I, compression and deformation of CCA or ICA in 4 tumors and JV in 28 tumors; type II, obliteration of IJV on segmental axial CT views in 13 tumors; type III, displacement of CCA or ICA in 14 tumors and JV in 18 tumors; type IV, tumor encasement of greater than 180 degrees of the circumference of the carotid vessels in 5 tumors; type V, the segmental deletion of fat or fascial planes between tumor and CCA or ICA in 16 tumors and JV in 33 tumors; and type VI, ill-defined CCA or ICA wall in 7 tumors. The respective sensitivity, specificity, and accuracy were 36.4%, 100%, and 84.1% for compression and deformation of CCA or ICA; 84%, 63.2%, and 75% for compression and deformation of JV; 52%, 100%, and 72.7% for obliteration of JV in segmental axial CT views; 36.4% to 52%, 53.8% to 69.7%, and 61.4% for displacement of CCA or ICA and JV; 18.5%, 100%, and 50% for tumor encasement of greater than 180 degrees of the circumference of the carotid vessels; 90.9%, 81.8%, and 84.1% for partial fat or fascia deletion between tumor and CCA or ICA; 92%, 47.4%, and 72.7% for partial fat or fascia deletion between tumor and JV; and 36.4%, 90.9%, and 77.3% for ill-defined CCA or ICA wall. CONCLUSIONS Various CT findings are of value in the diagnosis of oral-maxillofacial and neck malignant tumors that affect the carotid arteries and jugular veins. Comparatively, the signs of compression and deformation of the CCA or ICA, segmental obliteration of the JV, undefined CCA or ICA wall, and fat or fascial plane deletion between a tumor and the CCA or ICA may be valuable in diagnosing ICA and JV invasion, although accurate diagnosis of CCA or ICA involvement by the oral-maxillofacial and neck malignant tumors remains difficult.

Myoepithelioma of the Parotid Gland : CT Imaging Findings

BACKGROUND AND PURPOSE: Myoepitheliomas (MEs) are rare tumors of the parotid gland. Only a few case reports describing CT imaging features of ME have been published. The aim of this study was to describe and characterize the CT findings of MEs of the parotid gland. MATERIALS AND METHODS: We retrospectively reviewed CT images of ME with pathologic correlation in 10 cases (4 men and 6 women; age range, 30–70 years) collected between August 2003 and October 2007 from our pathologic database. All of the CT images were retrospectively evaluated with respect to the location, size, marginal morphology, enhancement, and enhancement pattern by 2 experienced radiologists. RESULTS: Nine tumors were located in the superficial lobe of the parotid gland, and 1 was located in the tail of parotid gland. All of the tumors abut on the capsule of the gland. Nine tumors had well-defined margins with lobulations in 5 patients. Two cases showed homogenous enhancement. In the other 8 cases, the enhancement was inhomogeneous because of enhancing nodules and nonenhancing areas of linear bands, slitlike-shaped or of cystic configuration. CONCLUSION: CT imaging findings of MEs were well circumscribed, enhancing the mass lesion with smooth or lobulated margins, located chiefly in the superficial lobe and abutted on the capsule of the gland. They may contain enhancing nodules and nonenhancing areas of linear bands, slitlike-shaped or of cystic configuration. Although MEs are a rarity, they should be suspected when a tumor shows all of the characteristics noted here.

The lesions of the pterygopalatine and infratemporal spaces: Computed tomography evaluation

OBJECTIVE The purpose of this study was to categorize the computed tomography features of lesions affecting the pterygopalatine fossa and infratemporal fossa and thus aid in the diagnosis of these lesions. DESIGN Eighty-six patients with lesions of the pterygopalatine fossa and infratemporal fossa were examined with computed tomography; the lesions were confirmed by both surgery and biopsy. The patients were divided into three groups: group I consisted of patients in whom the lesions had originated in one or both fossae; group II, of patients in whom the lesions originated in other oral and maxillofacial regions but showed extension into the pterygopalatine and infratemporal fossae; and group III, of patients in whom the lesions had multicentric origins. RESULTS Of the 11 cases in group I, demarcation was confined to both fossae in 4 patients, and involvement of the adjacent structures was shown on computed tomography images in 7 patients. Involved structures included the maxillary sinus (4 sides), nasal cavity (3 sides), mandibular ramus (6 sides), buccal space (2 sides), base of the skull (5 sides), palate (3 sides), and parapharyngeal space (5 sides). In the 70 cases in group II, computed tomography images showed that lesions had invaded both fossae via following routes: (1) 40 lesions in the maxillary sinus had infiltrated posterolaterally into 26 pterygopalatine and 39 infratemporal fossae; (2) two nasal cavity and three nasopharynx tumors had infiltrated laterally or lateroanteriorly into five pterygopalatine and one infratemporal fossae; (3) lesions originating in mandibular rami (9 lesions), buccal regions (4 lesions), parapharyngeal spaces (1 lesion) and parotid glands (1 lesion) had intruded medially into 15 infratemporal fossae; (4) two temporal bone tumors had encroached inferiorly on two infratemporal fossae; (5) four palate tumors had led to involvement of three pterygopalatine and four infratemporal fossae; and (6) four inflammatory diseases of the facial spaces involved two pterygopalatine and four infratemporal fossae. Group III lesions (5 cases) affecting one pterygopalatine and five infratemporal fossae were hemangiomas; one was a malignant lymphoma. CONCLUSION Group I lesions may involve the adjacent anatomic structures of both pterygopalatine and infratemporal fossae in every direction. Group II lesions that correspond to the various origins of the maxillofacial region have different pathways of infiltration into the pterygopalatine or infratemporal fossae. Computed tomography examination is very important in the evaluation of lesions involving the pterygopalatine and infratemporal fossae.

Osteosarcoma of the jaws: demographic and CT imaging features

OBJECTIVE The aim of this study was to evaluate the patient demographic and CT imaging findings of primary osteosarcoma of the jaws. METHODS 88 primary osteosarcomas of the jaws histopathologically diagnosed during 1997-2007 were reviewed. 21 cases of CT images were reviewed. RESULTS Of 88 patients, 51 (58%) had tumours in the mandible and 37 (42%) in the maxilla. The mean age was 37.8 years (range 9-80 years). The male-to-female ratio was 1.32:1. The mean age of patients with mandibular lesions was 41.04 years and in those with maxillary lesions it was 33.3 years. CT imaging findings were available in 21 patients. In the maxilla (n = 9), all tumours (100%) arose from the alveolar ridge. In the mandible (n = 12), most tumours (9 cases, 75%), arose from the ramus and/or condyle. All except two lesions had the epicentrum within the medullary cavity of the involved bone. The presence of periosteal reaction was demonstrated in 13 cases (62%). Soft-tissue extension was present in 18 lesions (86%), with calcification identified in 13 (72%). CONCLUSIONS This study provides age, sex distribution, location and CT imaging features of primary osteosarcoma of the jaws.

MR Imaging Assessment of Temporomandibular Joint Soft Tissue Injuries in Dislocated and Nondislocated Mandibular Condylar Fractures

BACKGROUND AND PURPOSE: Evaluation of temporomandibular joint (TMJ) soft tissue injuries after condylar fractures remains a challenge with use of conventional radiography and CT. The aim of this study was to explore MR imaging in the assessment of TMJ soft tissue injuries after condylar fractures. MATERIALS AND METHODS: Eighty subjects (118 TMJs) with condylar fractures were examined with sagittal and coronal MR imaging. Proton attenuation and T2-weighted sequences were the key sequences in our imaging protocol. All of the condylar fractures were classified into condylar fractures with dislocation (group 1, 108 TMJs) and without dislocation (group 2, 10 TMJs). RESULTS: MR imaging demonstrated the following TMJ soft tissue injuries: 1) disk displacements (91.5%, 105 [97.2%] in group 1 and 3 [30%] in group 2; P < .01). Almost all disk displacements in group 1 were in the anteroinferior direction; 2) abnormal signal intensities of retrodiskal tissues (87.3%, 98 [88.3%] in group 1 and 5 [50%] in group 2; P < .05); 3) joint effusion (85.6%, 95 [88%] in group 1 and 6 [60%] in group 2; P > .05); 4) abnormal inferoposterior attachments of disks (87.3%, 96 [88.9%] in group 1 and 7 [70%] in group 2; P > .05) and joint capsules (85.6%, 94 [87%] in group 1 and 7 [70%] in group 2; P > .05). CONCLUSIONS: There were significant differences of disk displacement and signal intensities of retrodiskal tissues between both fractures. Most dislocated condylar fractures were characterized with anteroinferior disk displacements along with the fractured fragments. MR imaging could provide additional information of TMJ soft tissue injuries after condylar fractures.

Synovial chondromatosis of the temporomandibular joint: MRI findings with pathological comparison.

OBJECTIVES The aim of this retrospective study was to characterize MRI findings of synovial chondromatosis in the temporomandibular joint (TMJ) by correlation with their pathological findings. METHODS 22 patients with synovial chondromatosis in unilateral TMJ were referred for plain MRI prior to surgical management and pathological examinations. Parasagittal and coronal proton density-weighted imaging and T₂ weighted imaging were performed for each case. RESULTS MRI demonstrated multiple chondroid nodules and joint effusion in all patients (100%) and amorphous iso-intensity signal tissues within expanded joint space and capsule in 19 patients (86.4%). On T₂ weighted imaging, signs of low signal nodules within amorphous iso-intensity signal tissues were used to determine the presence of attached cartilaginous nodules in pathology, resulting in 100% sensitivity, 60% specificity and 90.9% accuracy. Signs of low and intermediate signal nodules within joint fluids were used to detect loose cartilaginous nodules and resulted in 80% sensitivity, 42.9% specificity and 68.2% accuracy. CONCLUSIONS MRI of synovial chondromatosis in TMJ was characterized by multiple chondroid nodules, joint effusion and amorphous iso-intensity signal tissues within the expanded space and capsule. The attached cartilaginous nodules in pathology were better recognized than the loose ones on MRI. Plain MRI was useful for clinical diagnosis of the disorder.

Malignant tumors and chronic infections in the masticator space: preliminary assessment with in vivo single-voxel 1H-MR spectroscopy.

BACKGROUND AND PURPOSE: Differential diagnosis between malignant tumors and chronic infections in the masticator space remains challenging. The purpose of the study was to categorize various changes of both lesions by using single-voxel 1H-MR spectroscopy. MATERIALS AND METHODS: Twenty-four masticator space lesions, 7 chronic infections, and 17 malignant tumors were assessed with 1H-MR spectroscopy before treatment procedures. The MR spectroscopic findings were compared with surgical and histopathologic results. Localization technique for 1H-MR spectroscopy was made by a point-resolved spectroscopy sequence at an echo time of 144 ms. Choline (Cho) signals (identified at 3.2 ppm) and Cho signal intensity-to-noise ratio (Cho/noise) were considered as evaluating criteria. RESULTS: All the lesions were found with 3 1H-MR spectroscopic types: type 1, lesions without Cho signals (3 chronic infections); type 2, lesions with Cho signals and Cho/noise ratio <3 (4 chronic infections and 4 malignant tumors); and type 3, lesions with Cho signals and Cho/noise ratio >3 (13 malignant tumors). The mean ± SD of the Cho/noise ratio between chronic infections and malignant tumors was 2.31 ± 0.19 and 5.76 ± 3.29 (P < .01), respectively. CONCLUSION: In vivo single-voxel 1H-MR spectroscopy may be helpful in the assessment of masticator space lesions. Differences of Cho signals and Cho/noise ratios between malignant tumors and chronic infections provide valuable information in the differentiation of these 2 lesions.

Haemophilic pseudotumour of the mandible

Haemophilic pseudotumour (HP) of bone is a rare condition that occurs in patients with haemophilia. To date, only approximately 17 cases have been reported in the mandible. Herein, we present imaging findings of a histopathologically proven HP involving the left mandibular region in a 9-year-old Chinese boy.

Non-Hodgkin lymphoma involving the parotid gland: CT and MR imaging findings

OBJECTIVES As an uncommon neoplasm, parotid non-Hodgkin lymphoma (NHL) comprises mucosa-associated lymphoid tissue (MALT) and non-MALT lymphomas. Both types of lymphoma vary in prognosis and treatment. The aim of this study was to explore CT and MRI characteristics of these two types of lymphoma. METHODS 61 cases of parotid NHL, 34 MALT and 27 non-MALT lymphomas with histopathological confirmation were examined with routine CT and MR scans prior to treatment, and retrospectively reviewed. RESULTS On CT and MRI, 34 MALT lymphomas presented with 11 solid and 23 solid-cystic forms, whereas 27 non-MALT lymphomas presented with 25 solid and 2 solid-cystic forms (p < 0.01). CONCLUSIONS Parotid MALT lymphoma is characterized mainly by the solid-cystic form, whereas non-MALT lymphoma is characterized mainly by the solid form. The differences on CT and MRI can offer helpful information for differentiation of both types of parotid NHL.

Evaluation of solid lesions affecting masticator space with diffusion-weighted MR imaging

OBJECTIVE The aim of this study was to evaluate the value of diffusion-weighted magnetic resonance (MR) imaging in differentiating various masticator-space solid lesions. STUDY DESIGN Before surgery and/or pathologic verification, diffusion-weighted echo-planar MR imaging was performed on 78 subjects who had lesions in their masticator spaces. Based on their pathologic outcomes, lesions were classified into 3 groups: group 1: benign tumors and tumor-like lesions (23 cases); group 2: inflammatory diseases (14 cases); and group 3: malignant tumors (41 cases). Mean apparent diffusion coefficients (ADCs) were calculated from diffusion-weighted MR images that were obtained with a b factor of 0 and 1,000 s/mm(2). Differences between groups and lesion types were statistically compared with the Kruskal-Wallis and Mann-Whitney U tests. RESULTS The ADCs were significantly different (P = .0001) among the 3 groups, between group 1 (1.52 +/- 0.29 [SD] x 10(-3) mm(2)/s) and group 2 (1.01 +/- 0.31 x 10(-3) mm(2)/s), and between group 1 and group 3 (1.11 +/- 0.29 x 10(-3) mm(2)/s). There was no statistically significant difference (P = .31) in ADCs between group 2 and group 3. In addition, there were significant differences between osteosarcomas (1.40 +/- 0.28 x 10(-3) mm(2)/s) and inflammatory diseases (P = .038) and between osteosarcomas and carcinomas (1.11 +/- 0.26 x 10(-3) mm(2)/s; P = .035). CONCLUSIONS Diffusion-weighted MR imaging may be valuable in differentiating between benign solid lesions and malignant tumors in the masticator space. Inflammatory lesions cannot, however, be separated from most malignant tumors, except for osteosarcomas.