膝关节腘窝肿物的MRI表现

目的探讨发生于膝关节腘窝肿物的MRI影像特征。方法对50例经手术病理证实的膝关节腘窝肿物的MRI表现,进行回顾性分析并与病理结果对照。结果囊性肿物32例(包括Baker囊肿21例、腱鞘囊肿7例、半月板囊肿4例)均表现为液体的信号特点,实性肿物18例(包括腱鞘巨细胞瘤6例,滑膜骨软骨瘤病4例、血管瘤及滑膜肉瘤各2例、脂肪瘤及神经鞘瘤各1例、血肿2例)MRI信号特征各异,且与各肿物组织病理成分相关。结论 MRI能清晰显示腘窝肿物的形态、大小及与周围组织的关系,多数腘窝肿物MRI信号具有一定的特征性。     

Synovial sarcoma: dynamic contrast-enhanced MR imaging features

Objective. To determine whether previously described so-called malignant dynamic contrast-enhanced magnetic resonance (MR) imaging features – early start, peripheral enhancement and early plateau or washout phase – occur consistently in synovial sarcoma. Design and patients. Dynamic contrast-enhanced MR images of 10 patients with histologically proven synovial sarcoma were reviewed. The start, pattern and progression of tumor enhancement were assessed and correlated with histopathology. Results. In all patients, the time interval between arterial and early tumor enhancement was less than 7 s (mean 4.40 s, SD 2.09 s). Six synovial sarcomas showed enhancement with a subsequent rapidly progressive linear increase in signal intensity followed by a plateau in one lesion and washout in five. Four lesions showed a late sustained increase in enhancement after the initial rapid increase in enhancement. The pattern of initial enhancement was peripheral in only two lesions, diffuse in four and heterogeneous in four lesions. Conclusions. Enhancement of tumor within 7 s after arterial enhancement is, of the three parameters described previously, the only sign that occurs consistently in synovial sarcoma. Received: 2 May 2000 Revision requested: 26 July 2000 Revision received: 19 September 2000 Accepted: 21 September 2000     

Computed tomography and magnetic resonance imaging findings in cerebral hydatid disease

Purpose: The purpose of this study was to describe the discriminative computed tomography (CT) and magnetic resonance imaging (MRI) features of cerebral hydatid disease.Methods: The CT and MRI findings of four cases of surgically proven cerebral hydatid cysts were retrospectively reviewed. Results: CT demonstrated well-defined cystic lesions with no perilesional oedema and no contrast enhancement in all cases except one recurrent disease that showed both peripheral oedema and rim enhancement. MR images revealed well-defined cystic lesions with a quite clear rim that showed relative hypointensity limited to some aspects of the cyst walls on T2-weighted images. The cysts were spherical and obvious mass effect was observed on both CT and MR examinations. Conclusions: Although the cystic nature of intracranial hydatid disease could be equally well demonstrated on CT and MR examinations, CT is superior in detecting calcification of the cyst wall or septa, when present, and MR is better in demonstrating cyst capsule, detecting multiplicity and defining the anatomic relationship of the lesion with the adjacent structures and helps in surgical planning.     

Synovial sarcoma of the soft tissues: prognostic significance of imaging features

OBJECTIVE: This study assessed the prognostic value of computed tomography (CT) and magnetic resonance (MR) imaging features in synovial sarcoma of the soft tissues. METHODS: CT and MR imaging studies were performed in 30 patients with pathologically confirmed synovial sarcoma of the soft tissues. CT and MR imaging findings obtained by 2 radiologists with agreement by consensus were compared for histopathologic features including tumor grade. Univariate analyses were conducted to clarify the impact of imaging findings on overall survival with a medium duration of 32 months. Multivariate analysis was estimated using a Cox proportional hazards model with the relative risk of each variable. RESULTS: Statistically significant imaging findings favoring a diagnosis of high-grade tumor included proximal distribution (P < 0.01), large tumor size (>10 cm, P < 0.05), the absence of calcification (P < 0.05), tumor possessing cyst (P < 0.01), the presence of hemorrhage (P < 0.05), and the presence of triple signal pattern (P < 0.05). Univariate analysis showed that proximal distribution (P < 0.05), tumor size larger than 5 cm (P < 0.01), the absence of calcification (P < 0.01), the presence of hemorrhage (P < 0.05), and the presence of triple signal pattern (P < 0.05) had a significant association with the disease-free survival (DFS). Multiple logistic regression models revealed that tumor size larger than 10 cm had a significant impact on the DFS with relative risk of 18.8 (P < 0.05). CONCLUSION: CT and MR imaging studies allow prognosis prediction in patients with synovial sarcoma of the soft tissues.     

MR imaging of synovial sarcoma.

The MR imaging findings in 12 cases of synovial sarcoma are illustrated. The MR appearance most indicative of the tumor is an inhomogeneous septated mass with infiltrative margins located close to a joint, a tendon, or bursae, especially if soft-tissue calcification can be seen on CT scans or plain radiographs.     

Imaging of benign and malignant soft tissue masses of the foot

The foot is a relatively uncommon site of neoplastic and non-neoplastic soft tissue tumors. Although it contains a relatively small amount of somatic soft tissue elements, the foot is considerably rich in tendons, fasciae, retinaculae, and synovium. Corresponding to this distribution of soft tissue elements, some soft tissue lesions, such as giant cell tumor of tendon sheath, fibromatosis, and synovial sarcoma, are commonly seen in this location. Vascular tumors represent common soft tissue masses of the foot as well. Magnetic resonance imaging is the modality of choice in the assessment of soft tissue tumors. The presence of a suspected lesion can be confirmed and tumor margins can be defined accurately. In general, MRI does not provide histologic specificity, but considering some MR features may often help in correctly distinguishing benign from malignant lesions. In addition, characteristic features of the most common benign tumors (i.e., fibromatosis, cavernous hemangioma) and reactive processes of the foot (ganglion cyst, Morton's neuroma) often suggest a specific diagnosis. Electronic Publication     

Giant cell tumors of the tendon sheath may present radiologically as intrinsic osseous lesions

The purpose of this study was to explain radiographic features of giant cell tumors of the tendon sheath (GCTTS), in particular, osseous extension, by correlating imaging findings with histology in order to increase the accuracy of radiological diagnosis. In a series of 200 consecutive osseous (pseudo) tumors of the hand, on radiography, six patients presented with an intrinsic osseous lesion caused by a histologically confirmed neighboring GCTTS. Available radiographs, computed tomography (CT), and contrast-enhanced magnetic resonance (MR) images were correlated with histology. Radiography showed osseous lesions consisting of well-defined cortical defects in four (one of whom also demonstrated cortical scalloping) and a slightly expansile, well-defined osteolytic lesion in two patients. MR obtained in four patients showed the extraosseous tumor invading/eroding bone and causing cortical scalloping (three and one patients, respectively). Extension depicted on MR was confirmed on the two available resection specimens. All lesions were polylobular (cauliflower or mushroom like) and neighbored tendon sheaths. Dense collagen and hemosiderin-loaded macrophages explained the high CT attenuation and the low MR signal intensity on T2-weighted images that was observed in all four MR and in all two CT scans. The high density of proliferative capillaries explained the marked enhancement observed in all four patients with gadolinium (Gd)-chelate-enhanced MR imaging. GCTTS is a soft tissue (pseudo) tumor that may invade bone and as a consequence mimick an intrinsic osseous lesion on radiographs. In such cases, specific MR and CT features that can be explained by histological findings can be used to suggest the correct diagnosis.     

Synovial cysts of the lumbosacral spine: diagnosis by MR imaging

Intraspinal synovial or ganglion cysts are uncommon lesions associated with degenerative lumbosacral spine disease. CT usually reveals cystic lesions adjacent to a facet joint, and they may show calcification. MR imaging of four surgically confirmed cases of intraspinal synovial cysts revealed subtle signal changes compared with CSF. Short TR/TE images showed the lesions to be slightly hyperintense in three cases and isointense in one case. Long TR/TE sequences revealed a hyperintense appearance in two cases and a hypointense appearance in the others. A peripheral rim of decreased signal on long TR/TE images probably reflects fine calcification or hemorrhage in the margins of the cysts. The multiplanar and contrast characteristics of MR make this technique well suited to the diagnosis of herniated disk, degenerative facet disease, and synovial cyst.     

Synovial cysts of the lumbosacral spine: diagnosis by MR imaging

Intraspinal synovial or ganglion cysts are uncommon lesions associated with degenerative lumbosacral spine disease. CT usually reveals cystic lesions adjacent to a facet joint, and they may show calcification. MR imaging of four surgically confirmed cases of intraspinal synovial cysts revealed subtle signal changes compared with CSF. Short TR/TE images showed the lesions to be slightly hyperintense in three cases and isointense in one case. Long TR/TE sequences revealed a hyperintense appearance in two cases and a hypointense appearance in the others. A peripheral rim of decreased signal on long TR/TE images probably reflects fine calcification or hemorrhage in the margins of the cysts. The multiplanar and contrast characteristics of MR make this technique well suited to the diagnosis of herniated disk, degenerative facet disease, and synovial cyst.     

腱鞘巨细胞瘤MRI表现及信号特点

目的:总结腱鞘巨细胞瘤的MRI表现及信号特点。方法:回顾性分析14例经手术和病理证实的腱鞘巨细胞瘤患者的病例资料,其中2例为术后复发。所有病例均行MRI平扫,其中1例行增强扫描,分析所有病例的MRI信号特征及发病部位。结果:14例中局限性12例,弥漫性2例,肿瘤信号与正常骨骼肌对比,11例T1WI上以等信号为主,3例以稍低信号为主;T2WI信号呈多样性,8例以稍高信号为主,2例呈稍低信号,2例呈等信号,2例呈混杂信号。14例可见T1WI及T2WI上均呈低信号病灶。结论:腱鞘巨细胞瘤多发生于手、足等肢体远端,且以局限型多见。MRI信号呈多样性,但T1WI及T2WI双向低信号为其特征性表现,且其对诊断、指导临床治疗和随访具有重要价值。     

Macroscopic vascular invasion in synovial sarcoma evident on MRI

We present a case of recurrent synovial sarcoma in the soft tissues of the calf, where MR imaging not only confirmed the diagnosis of tumour recurrence, but also demonstrated direct venous invasion and tumour thrombus within the popliteal vein and its tributaries. Venous invasion has particular relevance to synovial sarcoma prognostication and should be actively sought on MR imaging. To our knowledge this is the first reported case in the English literature of histologically proven macroscopic popliteal vein invasion from a synovial sarcoma demonstrated on MR imaging.     

Magnetic resonance imaging of knee trauma

This article reviews the magnetic resonance (MR) appearance of normal knee anatomy and the role of MRI in the evaluation of knee trauma. Images acquired in the sagittal plane are the most useful. A combination of T₁- and T₂-weighted spin echo pulse sequences is most commonly employed. A meniscal tear is identified by an intrameniscal signal which extends to the joint surface. MR and arthroscopic findings agree in more than 90% of patients. It is important to be familiar with the MRI appearance of normal anatomic variants that may be confused with meniscal tears: the transverse geniculate ligament, the hiatus of the popliteal tendon sheath, and the meniscofemoral ligaments. Tears in the anterior cruciate, posterior cruciate, and collateral ligaments are also depicted.The following article is one in a series of review articles which represent expansions of papers presented at the annual meeting of the International Skeletal Society and were solicited by the editors     

Fibroma of the tendon sheath of the long head of the biceps tendon

Fibroma of the tendon sheath is a benign tumor that is less common than giant cell tumor of the tendon sheath. Both tumors may present as a painless, slowly enlarging mass. Radiological findings may be similar for both tumors. Histologically, fibroma of the tendon sheath lacks the hemosiderin-laden macrophages that are typical for giant cell tumor of the tendon sheath. We report on a 49-year-old woman with fibroma of the tendon sheath of the long head of the biceps tendon. In our case, on MR images, we observed band-like hypointense areas centrally in the tumor, mild patchy contrast enhancement, and most importantly, no decrease of signal intensity on gradient echo images. These characteristics reflected histological findings.     

Synovial sarcomas of the head and neck: CT and MR imaging findings of eight patients

BACKGROUND AND PURPOSE: Synovial sarcomas are soft-tissue tumors that rarely occur in the head and neck. The purpose of this study was to evaluate their CT and MR imaging appearance and to show that they may have a surprisingly benign imaging appearance. METHODS: Eight patients with histologically proved synovial sarcoma underwent CT; additionally, MR imaging examinations were performed in five of the eight cases. Attenuation and signal intensity on CT scans and MR images, respectively, were studied by two radiologists. They analyzed the location, size, margins, homogeneity, presence of adenopathies and infiltrative signs, and enhancement after injection of contrast medium. RESULTS: Four tumors were located in the hypopharynx, two arose from the infratemporal fossa, one arose from the maxillary sinus, and one arose from the faucial tonsil. Tumor sizes ranged from 27 to 70 mm. On CT scans and MR images, six lesions were homogeneous and well defined, with smooth margins. The remaining tumors were heterogeneous. In two cases, adjacent tissues were invaded. Calcifications were observed in one case and adenopathy in two cases. In three cases, the lesions were isointense on T1-weighted MR images and hypointense on T2-weighted MR images, and in the other two cases in which MR imaging was performed, the lesions were both isointense and hypointense on both T1- and T2-weighted images. Only the two local recurrent lesions were multilocular. CONCLUSION: Synovial sarcomas are aggressive sarcomas that may appear "benign" in some cases. In a young man, a synovial sarcoma may be suspected when a well-demarcated, homogeneous lesion is found in the head and neck.     

Pigmented villonodular synovitis and giant cell tumor of the tendon sheath: scintigraphic findings in 10 cases

The purpose of this report was to determine the pattern of thallium (T1-201) uptake in pigmented villonodular synovitis (PVNS) and giant cell tumor of the tendon sheath (GCTTS) and to evaluate for features that might help to distinguish these lesions from malignant disease. Scintigraphic images from patients subsequently found to have pigmented villonodular synovitis confirmed by histopathologic analysis were assessed. The patients had been evaluated with T1-201 scintigraphy for a suspicious musculoskeletal lesion. All 6 patients with PVNS had significant T1-201 uptake on the early images with retention on the delayed images. The T1-201 activity was in a juxta-articular location and generally conformed to the synovial cavity with scattered irregular nodular components. Of 4 cases of giant cell tumor of the tendon sheath, all had T1-201 uptake on the early images, and 3 cases (75%) also had uptake on the delayed images. T1-201 uptake is observed almost invariably in pigmented villonodular synovitis on both early and delayed images and can simulate the findings of malignant disease. Features that should raise suspicion of PVNS include close proximity to a joint, especially with distribution corresponding to that of the synovial cavity. When T1-201 activity is detected in a lesion in the hand or foot, giant cell tumor of the tendon sheath should be considered. Magnetic resonance imaging will often aid in the differentiation by demonstrating features of hemosiderin degradation products.     

Magnetic resonance appearance of peripheral nerve sheath tumors

Magnetic resonance imaging (MRI) was used to evaluate 22 histologically proven peripheral nerve sheath tumors, approximately two-thirds of which arose in the lower extremity. The histologic distribution was as follows: 12 schwannomas, 7 neurofibromas, and 3 malignant peripheral nerve sheath tumors (2 of which occurred in patients with neurofibromatosis). Most lesions demonstrated an intermediate to moderately bright signal on T₁-weighted images and were minimally inhomogeneous. All lesions were moderately bright on proton-density-weighted images and bright on T₂-weighted images, again with variable inhomogeneity. The extent of the tumor was best assessed on proton-density- and T₂-weighted images. Smooth margins were noted in 19 lesions. Of the 3 remaining lesions, 2 were malignant (but had been subjected to biopsy prior to MRI), and the other lesion was a plexiform neurofibroma. MRI accurately determined the relationship between the lesion and the adjacent neurovascular structures and muscles, thereby assisting surgical management. On MRI, 5 lesions demonstrated coexistent subtle muscle atrophy along the longitudinal axis of surrounding or distally innervated musculature. This latter finding, together with the presence of a tumor in the vicinity of a large nerve trunk, suggests a peripheral nerve sheath neoplasm.The opinions and assertions contained herein are the private views of the authors and do not reflect the views of the Uniformed Services University of the Health Sciences, the Department of the Army, or of the Department of Defense     

Synovial sarcomas of the head and neck: CT and MR findings.

The authors present three cases of histologically proved synovial sarcoma. CT is useful in assessing erosive or destructive changes in bone, and in demonstrating calcifications. MR characteristics are nonspecific; calcifications within these tumors can be missed on MR. MR can help to assess tumor extension, vascular invasion, and hemorrhage within the tumor.     

Primary cerebral neuroblastoma: CT and MR findings in 12 cases

A retrospective CT, MR, and clinical study was performed in 12 patients, five children and seven adults, with histologically proved primary CNS neuroblastoma. The CT and MR appearances of this neoplasia were more variable than generally recognized. Although seven tumors were predominantly intraparenchymal masses with calcification and cyst formation, five were intra- or juxtaventricular. CT was preferable to noncontrast MR both at initial diagnosis and follow-up for identification of calcification, recurrent tumor at surgical sites, and leptomeningeal disease. Noncontrast MR was useful primarily for localization of peri- and intraventricular lesions. We conclude that primary CNS neuroblastoma has a more variable radiographic appearance than is generally recognized, and that an intra- or periventricular epicenter is common.     

Primary cerebral neuroblastoma: CT and MR findings in 12 cases

A retrospective CT, MR, and clinical study was performed in 12 patients, five children and seven adults, with histologically proved primary CNS neuroblastoma. The CT and MR appearances of these neoplasia were more variable than generally recognized. Although seven tumors were predominantly intraparenchymal masses with calcification and cyst formation, five were intra- or juxtaventricular. CT was preferable to noncontrast MR both at initial diagnosis and follow-up for identification of calcification, recurrent tumor at surgical sites, and leptomeningeal disease. Noncontrast MR was useful primarily for localization of peri- and intraventricular lesions. We conclude that primary CNS neuroblastoma has a more variable radiographic appearance than is generally recognized, and that an intra- or periventricular epicenter is common.     

Synovial sarcoma arising in association with a popliteal cyst

Synovial sarcoma is a relatively common soft tissue sarcoma particularly in the adolescent and young adult. We report an unusual case of a synovial sarcoma arising within a popliteal cyst in a 13-year-old female presenting with bilateral popliteal cysts. MR imaging demonstrated the cyst with evidence of subacute haemorrhage and a discrete nodule of tumour. Received: 20 July 2000 Revision requested: 10 August 2000 Revision received: 24 August 2000 Accepted: 28 August 2000