Solitary hot spots in the ribs on bone scan: value of thin-section reformatted computed tomography to exclude radiography-negative fractures

PURPOSE: The purpose of this study was to classify solitary, scintigraphy-positive and radiography-negative rib lesions and to clarify the features of rib fractures by using thin-section reformatted helical computed tomography (CT). METHODS: Forty-seven patients whose whole-body bone scans showed a solitary hot spot in a rib as their first abnormal scintigraphic finding and whose plain radiograph showed negative or indeterminate results were examined by thin-section reformatted CT. Final diagnosis was based on follow-up over a 20-month period. RESULTS: The final diagnosis included 17 cases of fractures where CT findings were fracture line, focal sclerosis, and callus formation. Fourteen ribs demonstrated intramedullary, focal osteosclerosis, and 8 ribs did not demonstrate any abnormalities. Four metastatic lesions appeared as intramedullary mixture of osteolysis and osteosclerosis, or bone destruction. Four intramedullary lesions with cystic appearance remained unchanged. CONCLUSIONS: Thin-section reformatted helical CT delineated minute, radiographically occult fractures of the rib. Excluding fractures, helical CT can avoid further unnecessary examinations.     

0.6 T MR imaging of the cervical spine: multislice and multiecho techniques

During a 6 month period, 50 patients with signs and symptoms referable to the cervical spine were studied with a 0.6 T superconducting magnetic resonance (MR) imaging unit. The last 23 of these 50 patients were studied with combined multislice and multiecho techniques. In 38 of the 50 patients, abnormalities were demonstrated on MR images. Intramedullary lesions included syringomyelia (three cases), primary tumors (two), metastatic neoplasm (one), cord atrophy secondary to trauma (one), and multiple sclerosis (one). Intradural, extramedullary lesions included two neurofibromas and two Chiari malformations. The rest of the lesions were extradural: degenerative changes (10), spinal stenosis with cord compression (five), disk degeneration and/or herniation (five), postoperative changes (four), metastases to bone/epidural disease (three), and neurofibromatosis (one). Two patients had more than one abnormality. The MR findings were compared with available routine radiographs, computed tomographic (CT) scans with and without metrizamide, and myelograms. MR imaging was consistently better than routine CT scanning in the detection of lesions of the spinal cord and in directly imaging the effects on the spinal cord of extrinsic abnormalities such as spinal stenosis. Metrizamide-enhanced CT scanning detected all cases of syringomyelia, but it involved an invasive procedure. Myelography alone was slightly less sensitive and considerably less specific than MR in detecting intramedullary lesions and in distinguishing cord neoplasms from syringomyelia. Multislice, multiecho techniques with up to 240 msec echo times (TEs) were particularly helpful in the detection and characterization of extradural processes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Factors influencing visualization of vertebral metastases on MR imaging versus bone scintigraphy

OBJECTIVE: The purpose of this study was to investigate whether the location and size of vertebral body metastases influence the difference in detection rates between MR imaging and bone scintigraphy. MATERIALS AND METHODS: We retrospectively evaluated the vertebral body lesions detected on MR imaging in 74 patients with known widely disseminated metastatic disease. Three radiologists independently reviewed the MR images and bone scintigraphs. MR imaging findings included lesion size and its spatial relationship to the bony cortex (intramedullary, subcortical, and transcortical) and results were correlated with those of planar technetium 99m bone scintigraphy. RESULTS: Findings on bone scans were negative for all intramedullary lesions without cortical involvement shown on MR imaging, regardless of their size. Findings on bone scans (71.3% for transcortical and 33.8% for subcortical) were frequently positive for lesions with cortical involvement (trans- or subcortical), and the probability of positive findings on bone scans was also influenced by the lesion size. Statistical analysis showed a positive correlation among cortical involvement, lesion size, and positive findings on bone scintigraphy (p < 0.0001). CONCLUSION: Location (the presence of cortical bone involvement on MR imaging) and size of the vertebral body metastases appear to be important contributing factors to the difference in detection rates between MR imaging and bone scintigraphy. Cortical involvement is likely the cause of positive findings on bone scans. Early vertebral metastases tend to be small and located in the medullary cavity without cortical involvement, and therefore, findings may be positive on MR images but negative on bone scans.     

软骨母细胞瘤的影像学表现及对比研究

目的分析对比软骨母细胞瘤的X线、CT及MR影像学特征。方法分析经病理证实且于2周内行X线、CT和MR检查的22例软骨母细胞瘤病人的影像学表现。2例同时行CT平扫和增强扫描,7例同时行MR平扫和增强扫描。结果病灶位于胫骨上端11例,股骨下端4例,髌骨2例,肱骨上端、股骨上端、颞骨和下颌骨各1例。1例恶性者发生于髂骨并同时累及骶骨。X线表现为骨质破坏(21),病灶内斑片状、斑点状和(或)条状致密影(5),病灶周围边界不清的斑片状硬化(10)。CT上,病灶呈类圆形分叶状(14),内为软组织密度(7),伴有斑片状、斑点状和(或)结节状钙化(15),病灶周围出现边界不清的斑片状硬化(15),病变周围软组织肿胀(18)。病灶在T2WI和脂肪预饱和T2WI均呈混杂信号(22),病灶周围髓腔内有边界不清的斑片状长T1长T2信号(20)。结论良性软骨母细胞瘤的影像学表现多具有特征性,X线平片、CT和MRI多数征象相互对应。     

Periosteal chondroid tumors: radiologic evaluation with pathologic correlation

OBJECTIVE: The purpose of this study was to determine whether the imaging features of periosteal chondroid tumors correlate with histopathology. MATERIALS AND METHODS: Twenty-two patients (nine women and 13 men; mean age, 33 years) with pathologically proven periosteal chondroid lesions were retrospectively reviewed. The imaging modalities included conventional radiography (n = 17), CT (n = 10), and MR imaging (n = 14). The images were reviewed by two osteoradiologists, with agreement by consensus. Evaluation criteria included lesion location, mineralization, and size; periosteal reaction; and cortical response. Intramedullary extension, adjacent intramedullary edema, soft-tissue edema, and intrinsic characteristics were also evaluated on MR imaging. After the evaluation, a radiologic diagnosis of chondroma or chondrosarcoma was obtained. An experienced osteopathologist who was unaware of the patient's medical history and radiologic findings reviewed all histopathology. Agreement between the radiologic and the histopathologic diagnosis was tested using the kappa analysis. Imaging features were correlated with the pathologic findings, and a statistical analysis was performed. RESULTS: Using strict pathologic criteria, we diagnosed 11 chondromas and 11 chondrosarcomas (nine, grade I; two, grade II). Moderate agreement was reached between the radiologic and the pathologic diagnosis (kappa = 0.55). The size of periosteal chondrosarcomas (range, 3-14 cm; median, 4 cm) was considerably larger than the size of the chondromas (range, 1-6.5 cm; median, 2.5 cm; p < 0.05). Other imaging features did not significantly correlate with benign versus malignant disease at pathology (all p > 0.05). CONCLUSION: A variable overlap existed in the imaging appearances of benign and malignant periosteal chondroid lesions, with size being the most reliable indicator in distinguishing the two lesions. This and the fact that histologic differentiation of the entities can be difficult, suggests that surgical wide excision may be the most appropriate procedure in treating patients with lesions greater than 3 cm.     

18F-NaF PET/CT骨显像在甲状旁腺功能亢进性骨病中的应用

目的 探讨甲状旁腺功能亢进性骨病18F-NaF PET/CT骨显像的影像学特点及其应用价值。 方法 收集30例经临床及术后病理证实为甲状旁腺功能亢进症患者[男性11例、女性19例,年龄18～71（52.3±13.5）岁]的18F-NaF PET/CT骨显像及99Tcm -亚甲基二膦酸盐（99Tcm-MDP）全身骨显像资料,回顾性分析其18F-NaF PET/CT骨显像特点,对比两种骨显像方法对该病局部骨骼病灶的检出情况,并根据Mirels评分标准对棕色瘤进行评分。 结果 两种骨显像方法定性结果一致,即骨显像阴性15例,阳性15例。甲状旁腺功能亢进性骨病在18F-NaF PET图像上大部分表现为以全身多骨弥漫性骨代谢增高为主的多种代谢性骨病征象,并发棕色瘤、骨硬化及病理性骨折等时表现为单发或多发局灶性显像剂异常分布,其中棕色瘤表现为局灶性显像剂浓聚、显像剂稀疏或病灶中心显像剂分布缺损伴边缘显像剂不均匀浓聚;同机CT图像上均表现为全身多骨多种形式的骨质吸收,其中,表现为广泛骨质疏松13例、伴棕色瘤7例、骨质硬化6例、骨质软化3例、病理性骨折3例。15例甲状旁腺功能亢进性骨病患者共检出局部骨骼病灶（棕色瘤、骨硬化、病理性骨折、假骨折）53个,其中,18F-NaF PET/CT骨显像全部检出,99Tcm-MDP全身骨显像检出32个。7例甲状旁腺功能亢进性骨病患者伴棕色瘤,位于长骨的棕色瘤病灶数共24个,其中9个Mirels评分大于9分。 结论 甲状旁腺功能亢进性骨病在18F-NaF PET/CT骨显像上的全身骨代谢及解剖学表现有一定的特征性表现,18F-NaF PET/CT骨显像结合同机CT上全身骨骼病灶的详细信息,在甲状旁腺功能亢进性骨病的诊断、鉴别诊断及病情严重程度评估中有更好的应用价值。     

Spinal cord schistosomiasis: MR imaging appearance with surgical and pathologic correlation

BACKGROUND AND PURPOSE: Spinal cord involvement is a rare manifestation of schistosomiasis. We describe the MR imaging findings of spinal cord schistosomiasis in correlation with surgery and pathology. METHODS: We report eight cases of spinal cord schistosomiasis. All patients were men (mean age, 16.7 years) with neurologic manifestations who had been referred for spinal MR imaging. In all cases, spinal masses were surgically removed. MR imaging findings were correlated with surgery and pathology. RESULTS: MR imaging showed moderate expansion of the distal spinal cord in all cases. Abnormalities were isointense to cord in T1 and patchy hyperintense in T2-weighted spin-echo images (n = 8). Three forms of contrast enhancement were recognized: (1) intramedullary nodular (n = 8); (2) peripheral (n = 8); and (3) linear radicular (n = 4). Total gross surgical removal of masses by using the Cavitron ultrasonic surgical aspirator was possible in six cases. Diagnosis was established by identification of ova in histopathologic studies: Schistosoma mansoni (n = 3), S. hematobium (n = 1), and uncertain species (n = 4). Intramedullary nodular enhancement was correlated to multiple schistosomiasis microtubercles. Peripheral enhancing lesions correlated to thickened leptomeninges infested by chronic granulomatous inflammatory cells and schistosoma eggs. Linear radicular enhancement correlated with thickened resected nervous roots infested by granulomatous cells and schistosoma eggs. CONCLUSION: Multinodular intramedullary contrast enhancement of the distal cord enabled correct presumptive preoperative MR imaging diagnosis of spinal schistosomiasis in three cases. Accurate diagnosis, through recognition of its MR imaging appearance, allows early treatment and better prognosis of spinal cord schistosomiasis.     

原发性骨骼恶性纤维组织细胞瘤影像表现与病理对照研究

目的 分析原发性骨骼恶性纤维组织细胞瘤(MFH)影像表现与病理的关系,以提高诊断准确性.方法 回顾性分析经手术病理证实的原发性骨骼MFH 13例,术前分别经X线平片、CT平扫、MR SE T1 WI、T2 WI和增强T1 WI检查,复习影像表现并与手术病理作对照.结果 13例原发骨骼MFH中,11例位于骨端,2例位于骨干,位于骨端者与骨性关节面的距离为1～5 cm.肿瘤呈溶骨性骨质破坏,直径5.3～12.7 cm.其中,破坏区偏心10例,破坏区内见少许分隔7例,周边不连续硬化11例,伪足样突起7例,骨膜增生2例,软组织肿块9例,所有患者软组织肿块体积较小.CT扫描显示肿瘤密度与肌肉密度相仿.在MR T1 WI肿瘤为等低信号,在T2 WI为混杂信号,T2 WI常见片状等低信号,病灶周围常见不完整的低信号环,环外见伪足样突起.动态增强呈进行性延迟强化,强化显著,且较均匀.大体病理显示病灶偏心,膨胀不明显,肿瘤多突破皮质形成范围较小的软组织肿块,呈结节状或假性包裹样,肿瘤内见纺锤形成纤维细胞和胞体较小的组织细胞样细胞,伴有数量不等的胶原纤维,细胞密集呈席纹状或放射状排列.肿瘤微血管丰富.结论 原发骨骼MFH好发于中年患者长骨骨端,T2 WI常见等低信号成分,增强扫描强化显著;MRI表现与病理关系密切.     

MR and other imaging methods in the investigation of mycetomas

Purpose: To report features of mycetomas (actino- and eumycetoma infection), which belong to the so-called rare bone infections, as evaluated by MR and other imaging methods and to assess chemotherapy treatment.Material and Methods: Twenty patients (average age 57 years) were diagnosed by different modalities. Analyses of 57 plain films, 31 three-phase bone scans, 28 CT and 35 MR examinations were performed. The MR protocol included T1-weighting without and with contrast, T2-weighted, proton density and fat suppressing sequences.Results: Signs of chronic osteomyelitis were seen in plain films of 10 patients (50%), but the healing process was difficult to assess. Bone scintigraphy was positive in 12 patients (60%). In 14 patients (70%), CT could demonstrate bone lesions, but the healing process was difficult to estimate in 4 patients. MR imaging provided accurate diagnostic information in 15 cases (75%). In 16 patients (80%), small lesions could be identified due to grains, which seemed to differentiate mycetoma from other infections and tumorous lesions. MR examination gave definitive answer about the healing process in 18 cases (90%).Conclusion: MR investigation was superior to the other imaging techniques in the evaluation of mycetoma and the assessment of therapy.     

Clear cell chondrosarcoma: radiographic, computed tomographic, and magnetic resonance findings in 34 patients with pathologic correlation

Objective To describe the radiographic features of clear cell chondrosarcoma (CCCS), including the computed tomographic (CT) and magnetic resonance (MR) findings, and to correlate them with the histopathologic findings.Design and patients A retrospective review was carried out of 72 patients with histopathologically confirmed CCCS. Imaging studies were available for 34 patients: conventional radiographs (n=28), CT scans (n=14), and MR images (n=15). Radiographic studies were reviewed by three radiologists who rendered a consensus opinion; the studies were correlated with the histopathologic findings.Results Of the 34 patients with imaging studies, 30 were male and 4 were female (mean age 38.6 years; range 11–74 years). Twenty-two lesions were in long bones (15, proximal femur; 1, distal femur; 1, proximal tibia; 5, proximal humerus) and 11 were in flat bones (5, vertebra; 4, rib; 1, scapula; 1, innominate). One lesion occurred in the tarsal navicular bone. Typically, long bone lesions were located in the epimetaphysis (19/22) and were lucent with a well-defined sclerotic margin and no cortical destruction or periosteal new bone formation. More than one-third of the long bone lesions contained matrix mineralization with a characteristic chondroid appearance. Pathologic fractures were present in six long bone lesions (4, humerus; 2, femur). Lesions in the proximal humerus were more likely to have indistinct margins (4/5) and extend into the diaphysis. Flat bone lesions were typically lytic and expansile and occasionally demonstrated areas of cortical disruption. Typically, matrix mineralization, when present, was amorphous. MR imaging, when available, was superior to conventional radiographs for demonstrating the intramedullary extent of a lesion as well as soft tissue extension. CT images better delineated the presence of cortical destruction and the character of matrix mineralization patterns. CCCS lesions were typically low signal intensity on T1-weighted images and moderately or significantly bright on T2-weighted images. Areas of lesion heterogeneity on T1- and T2-weighted images and on post-gadolinium T1-weighted images corresponded pathologically to areas of mineralization, intralesional hemorrhage, and cystic changes. Adjacent bone marrow edema was typically absent (12/15) or only minimally observed in a few cases (3/15). No cases examined with MR imaging demonstrated periosteal new bone formation.Conclusions CCCS typically presents radiographically as a geographic lytic lesion located in the epimetaphyseal region of long bones. Most commonly lesions are found in the proximal femur, followed by the proximal humerus. Lesions within the proximal humerus may exhibit more aggressive features. Lesions in the axial skeleton are typically expansile and destructive, often with soft tissue extension and lack of mineralization. MR imaging may show the presence or absence of bone marrow edema.     

CT and MR imaging findings in athletes with early tibial stress injuries: comparison with bone scintigraphy findings and emphasis on cortical abnormalities

PURPOSE: To prospectively compare computed tomography (CT), magnetic resonance (MR) imaging, and bone scintigraphy in athletes with clinically suspected early stress injury of tibia. MATERIALS AND METHODS: Medical ethics committee approval and informed consent were obtained. A total of 42 patients experiencing tibial pain due to early stress injuries were evaluated. Eight patients had bilateral involvement; thus, 50 tibiae were evaluated. All patients underwent initial radiography that was negative for injury. MR imaging, CT, and bone scintigraphy were performed in all patients within 1 month of onset of symptoms. Ten asymptomatic volunteers served as the control group. Location of stress injuries, types of bone alterations, and presence of periosteal and bone marrow edema were evaluated. Sensitivity, specificity, accuracy, and positive and negative predictive values of MR imaging and CT were assessed, as was sensitivity of bone scintigraphy. McNemar test was used to detect statistically significant differences. RESULTS: Sensitivity of MR imaging, CT, and bone scintigraphy was 88%, 42%, and 74%, respectively. Specificity, accuracy, and positive and negative predictive values were 100%, 90%, 100%, and 62%, respectively, for MR imaging and 100%, 52%, 100%, and 26%, respectively, for CT. Significant difference in detection of early tibial stress injuries was found between MR imaging and both CT and bone scintigraphy (McNemar test; P < .001 and P = .008, respectively). CONCLUSION: MR imaging is the single best technique in assessment of patients with suspected tibial stress injuries; in some patients with negative MR imaging findings, CT can depict osteopenia, which is the earliest finding of fatigue cortical bone injury.     

Whole-body bone marrow MRI in patients with metastatic disease to the skeletal system

PURPOSE: The purpose of this study was to evaluate the diagnostic potential of a whole-body bone marrow MR protocol in the detection of bone metastases. METHOD: Whole-body bone marrow MRI was performed in 18 patients with known malignant tumors and suspected bone metastases. The imaging protocol consisted of fast T1-weighted and STIR sequences applied in different anatomical positions covering the whole skeleton. MRI findings indicating bone metastases were compared with findings from bone scintigraphy. Metastatic lesions were confirmed by follow-up MR examinations, bone scintigraphy, radiography, or CT. RESULTS: A total number of 216 lesions were detected with MRI in comparison with 159 lesions detected with bone scintigraphy. Follow-up examinations confirmed 105 lesions. MRI detected 96 (91.4%) of the confirmed lesions, whereas bone scintigraphy detected 89 (84.8%). The entire examination, including patient positioning and changing of imaging coils, required 45 min of room time. CONCLUSION: Whole-body bone marrow MRI as used in this study is an effective method for evaluating the entire skeletal system in patients with suspected metastatic disease.     

Osteochondritis dissecans: analysis of mechanical stability with radiography, scintigraphy, and MR imaging

Twenty-one joints with stable (n = 9) or loose (n = 12) osteochondritis dissecans (OCD) lesions were examined in 15 subjects with plain radiography, three-phase bone scintigraphy, and magnetic resonance (MR) imaging. The lesion size and the thickness of the sclerotic margin as measured on plain radiographs were good parameters for predicting loosening. However, bone scintigraphy was more sensitive and specific in determining the mechanical stability of OCD lesions. MR imaging permitted direct visualization of loosening and fragment displacement; the latter permits differentiation of in situ loosening from a grossly unstable lesion. The noninvasive nature of bone scintigraphy and MR imaging makes them potentially preferable diagnostic modalities to arthrography for evaluating the mechanical status of OCD lesions.     

Imaging findings in symptomatic patients with femoral diaphyseal stress injuries

Purpose: To assess the imaging findings seen in symptomatic patients with stress injuries of the femoral diaphysis.

Material and Methods: Seven patients (5 F, 2 M, age range 16 to 56 years, mean 38 years) underwent imaging evaluation of the symptomatic lower extremity due to an insidious onset of thigh or groin pain unrelated to trauma. Imaging studies included radiography and magnetic resonance imaging (MRI) in seven patients, bone scintigraphy in five, and computed tomography (CT) in three.

Results: Radiographs depicted three frank fractures in two patients, and revealed findings of stress injury in six patients. Available scintigraphic and CT findings were abnormal. On MR images, a solitary fracture was seen in two patients; two patients presented with bilateral stress fractures of the femoral diaphysis; and all seven patients had the imaging features of stress injury. Femoral diaphyseal stress fractures (n = 6) appeared as linear regions of T1- and T2-weighted low signal intensity, surrounded by diffuse bone marrow edema. Three of the six frank fractures, with an evident fracture line, were longitudinal and parallel to the cortical surface.

Conclusion: Femoral diaphyseal stress fractures are often inconspicuous with conventional radiography. MRI depicts the changes of stress injury in the femoral diaphysis, and is particularly useful in documenting the presence, morphology, and extent of fracture(s), information valuable for definitive diagnosis and appropriate management.     

Solid variant of aneurysmal bone cysts in long tubular bones: giant cell reparative granuloma

OBJECTIVE: The purpose of this study was to determine the age distribution, location, and imaging features of histologically proven solid variants of aneurysmal bone cysts in long tubular bones. MATERIALS AND METHODS: We performed a retrospective review of imaging studies of histologically proven solid aneurysmal bone cysts in long bones between 1961 and 2001. There were 30 cases comprising 29 radiographic, six CT, and eight MR imaging examinations. The lesions were evaluated for bone involved, location within a long bone, matrix, size, soft-tissue mass, and MR imaging characteristics. The imaging findings were correlated with the histologic findings. RESULTS: The patients were 17 females and 13 males ranging in age from 2 to 58 years (mean, 18 years). The bones involved were the femur (n = 10), the ulna (n = 7), the tibia (n = 7), the humerus (n = 2), the radius (n = 2), and the fibula (n = 2). The lesions were five juxtaarticular, 13 metaphyseal, one diametaphyseal, and 11 diaphyseal. The location was eccentric in 20 cases, of which two were intracortical and two periosteal, and central in 10. Lesion size varied between 1 and 7 cm. Thirty-three percent of lesions were nonaneurysmal. Four lesions were mineralized. A soft-tissue mass was present in four cases. Four lesions showed a permeative-lytic pattern simulating a malignant process. Unusual findings included periosteal reaction and development of a solid aneurysmal bone cyst in a preexisting fracture. MR imaging showed solid elements in all cases and pronounced edema in 50% of cases. CONCLUSION: Solid aneurysmal bone cyst is a reactive nonneoplastic bone lesion with varied imaging characteristics; one third of lesions are nonaneurysmal.     

Cervicofacial actinomycosis: CT and MR imaging findings in seven patients

BACKGROUND AND PURPOSE: Cervicofacial actinomycosis is uncommon, but without proper treatment it causes extensive tissue destruction. Early diagnosis is critical but usually difficult with cultures or imaging. Our aim was to identify characteristic imaging features that facilitated diagnosis in seven patients with cervicofacial actinomycosis. METHODS: We retrospectively reviewed the CT and MR findings in seven patients with pathologically proved actinomycosis. Histologic diagnosis was made by means of surgical excision or biopsy in seven patients. Culturing was performed in two patients. Enhanced CT scans (n=7) and MR images (n=2) were evaluated for the location, margin, infiltrative nature, enhancement pattern, and presence of lymphadenopathy. RESULTS: CT and MR images showed either a well-defined (n=2) or ill-defined (n=5) mass. Involved areas included the nasal cavity (n=2), buccal space (n=1), pyriform sinus (n=1), aryepiglottic fold (n=1), oro- and hypopharynx (n=1) and tongue (n=1). Imaging confirmed the infiltrative nature, showing the tendency of the lesion to invade across tissue planes and boundaries (n=6). Moderate homogeneous contrast enhancement was seen on CT scans in six patients with several small low-attenuating foci (n=2). T1- and T2-weighted MR images showed intermediate signal intensity with moderate contrast enhancement (n=2). Reactive lymphadenopathy was associated in three patients. CONCLUSION: Although cervicofacial actinomycosis occurs infrequently, it should be included in the differential diagnosis when images show a soft-tissue mass with inflammatory changes and an infiltrative nature in the cervicofacial area.     

Telangiectatic osteosarcoma: radiologic-pathologic comparison

PURPOSE: To describe the imaging characteristics of a large series of telangiectatic osteosarcomas with pathologic findings for comparison. MATERIALS AND METHODS: The authors retrospectively reviewed 40 pathologically confirmed telangiectatic osteosarcomas. Patient demographics and images from radiography (n = 36), bone scintigraphy (n = 17), angiography (n = 4), computed tomography (CT) (n = 25), and magnetic resonance (MR) imaging (n = 27) were evaluated by three authors in consensus for lesion location, size, and intrinsic characteristics. There were 27 men (68%) and 13 women (32%) in the study, with an age range of 4-83 years (mean age, 24 years). RESULTS: Lesions frequently affected the femur, tibia, and humerus. Radiographs showed geographic bone lysis, a wide zone of transition, and matrix mineralization. CT demonstrated low attenuation, MR demonstrated high signal intensity on T2-weighted images, and both demonstrated hemorrhage, which simulated the appearance of aneurysmal bone cyst. Viable sarcomatous tissue surrounding hemorrhagic and/or necrotic regions was best seen at contrast material-enhanced CT and MR imaging, with thick peripheral, septal, and nodular enhancement in all cases. Subtle matrix mineralization in this viable tissue was best seen at CT. An associated soft-tissue mass was also seen in 19 of 25 cases (76%) at CT and in 24 of 27 cases (89%) at MR imaging. CONCLUSION: CT and MR imaging findings of telangiectatic osteosarcoma often include thick nodular tissue (and matrix mineralization at CT) in a largely hemorrhagic and/or necrotic osseous lesion with an associated soft-tissue mass, which allows distinction from aneurysmal bone cyst.     

Imaging features of subperiosteal aneurysmal bone cyst

PURPOSE: To analyze the imaging features of subperiosteal aneurysmal bone cyst. MATERIAL AND METHODS: The imaging material of 6 patients with biopsy-proved subperiosteal aneurysmal bone cyst was reviewed. Evaluation included patient demographics, lesion location and size, radiographic features, and intrinsic characteristics on CT and MR images. Review of histologic specimens was carried out by an experienced musculoskeletal pathologist. RESULTS: All lesions were located at the surface of long tubular bones (femur 3, tibia 2, humerus 1): 3 involved the diaphysis, 2 the dia/metaphysis, and 1 exclusively the metaphysis. Lesion size ranged from 2.5 to 6 cm in maximum diameter. Radiographs and CT images always showed a superficial bone defect, which on radiographs demonstrated irregular margins in 4 cases. All lesions caused an interrupted periosteal reaction (shell 3, trabeculated shell 1, Codman angle 2). MR images always showed a multicystic appearance with a hypointense rim, contrast-enhancing cyst walls, and fluid levels. Edema of adjacent soft tissues was present in all cases. CONCLUSION: Aneurysmal bone cyst in a subperiosteal location can demonstrate an aggressive radiographic appearance. MR imaging appears to be most valuable in the differential diagnosis, since it can demonstrate typical morphological features of the underlying process.     

脊髓室管膜下瘤的MR影像诊断

目的 研究脊髓内室管膜下瘤的MRI特征。方法 4例脊髓室管膜下瘤均行MR检查并经手术病理证实，均为男性，年龄15—47岁，平均36．3岁。回顾性分析脊髓内室管膜下瘤的MRI表现，结合术中所见总结MRI诊断与鉴别诊断要点。结果 4例脊髓内室管膜下瘤分别位于C3～T3、C2～6、T6～12、C1—T2段脊髓，肿瘤均位于脊髓腹侧，呈偏中心性生长。1例有轻度脊髓空洞。MR T1WI为等或低信号，信号不均，内有更低信号；T2WI为高信号。2例伴有小出血灶。增强扫描，3例肿瘤无强化或强化轻微，1例强化明显。结论 MRI可以很好评价脊髓内室管膜下瘤，当患者具备上述特点时高度提示脊髓内室管膜下瘤的可能。