Magnetic resonance signal alterations in the acute onset of heterotopic ossification in patients with spinal cord injury

The purpose of our study was to evaluate magnetic resonance (MR) signal characteristics of acutely forming heterotopic ossification (HO) in paralyzed patients. Fourteen patients with spinal cord injury (female n=2, male n=12, mean age 38.3 years) and acute onset of radiographically proven HO had contrast-enhanced 1.5-T MRI within 13.4±18.3 days of clinical onset of symptoms. MR signal alterations of affected muscles, fascia, subcutaneous tissue, skin and adjacent bone were evaluated. A diffuse T2-hyperintense signal of multiple muscle groups was seen in all patients (bilateral in 12) involving quadriceps (n=13, 93%), adductors (n=13, 93%) and iliopsoas (n=12, 86%) with contrast enhancement in n=11 (79%), n=8 (57%) and n=8 (57%) patients. All patients had nonenhancing areas (mean size 2×3.5×5.8 cm) within diffusely enhancing muscles. HO formation occurred around these nonenhancing areas in four patients with computed tomography follow-up. Other MR findings included fascial edema (n=14, 100%), fascial enhancement (n=13, 93%), subcutaneous edema (n=13, 93%), subcutaneous enhancement (n=12, 86%), bone marrow edema (n=5, 36%), and joint effusion (n=12, 86%). MRI reveals mostly bilateral edema and enhancement of muscles, fascia and subcutaneous tissue during acute onset of HO. HO develops in the periphery of well-defined areas of no enhancement.     

Musculoskeletal ultrasound in childhood

Ultrasonography is one of the first line imaging modalities for the evaluation of musculoskeletal disorders in children. This article provides an overview of the most important pathologic entities in which ultrasonography significantly contributes to the diagnostic workup.     

Paediatric ultrasound. Part 2: Other applications

This article focuses on small-parts US in children. The differential diagnosis of cystic neck masses primarily includes lymphangiomas, thyroglossal duct cysts and branchial cleft cysts. Solid masses may be represented from lymphadenopathies, cervical extensions of mediastinal thymus, fibromatosis colli, rhabdomyosarcomas and neuroblastomas. Salivary gland lesions are uncommon in children. Thyroid is best evaluated by US and nuclear scintigraphy. If US shows abnormal thyroid gland, the isotopic scan may be a good complementary method to confirm the diagnosis. Normal parathyroid glands are not visualised routinely by US because of their small size. Parathyroid adenomas are unusual in paediatrics. Ultrasound can be successfully used in the differential diagnosis of the painful scrotum especially with colour flow Doppler. The hallmark of ischaemia is a completely avascular testis. In the paediatric age group, the most common application of US to the musculoskeletal system is the evaluation of the infant hip in the first 6 months of life; however, the refinement of new transducers has further improved the ability of US equipment to evaluate a variety of other musculoskeletal disorders in children, involving tendons, muscles, nerves as well as soft tissue masses. Ultrasound can be a useful screening tool in newborns suspected of having closed spinal dysraphism.     

Benign osteochondromas and exostotic chondrosarcomas: evaluation of cartilage cap thickness by ultrasound

Ultrasonography (US) enables accurate assessment of the cartilage cap of exostoses. The cartilage cap appears as a hypoechoic layer covering the hyperechoic surface of the calcified part. Measurements of cap thickness with US were compared with measurements performed on pathological specimens in 22 resected exostoses and 2 exostotic chondrosarcomas. The US measurements proved to be very accurate, with a mean measurement error of less than 2 mm for cartilage caps less than 2 cm thick. The detection rate and measurement accuracy of US were higher than with computed tomography (CT) and comparable to magnetic resonance imaging (MRI), which were available in 14 and 10 cases, respectively. US appears to be a good procedure for evaluating the cartilage cap, which is usually thin for a benign exostosis and thick for a malignancy. In addition, other complications — such as bursa formation — are easily recognizable. The sole limitation is that US cannot visualize the cartilage cap when it is inwardly orientated or deeply located in soft tissues, which are both, however, relatively uncommon situations.     

MR imaging of soft-tissue masses: Role of gadopentetate dimeglumine

To assess the effectiveness of gadopentetate dimeglumine in the magnetic resonance (MR) imaging evaluation of soft-tissue masses without osseous involvement, 30 patients underwent MR imaging before and after administration of contrast material (0.1 mmol/ kg) of the 30 lesions, 22 were benign and eight were malignant; histologic confirmation was available in all lesions except one benign lesion. Overall, enhancement was detected in 26 (87%) of 30 lesions: 18 (82%) of the 22 benign lesions and eight (100%) of eight malignant lesions. Enhancement was characterized as homogeneous (two [11%] benign lesions, two [25%] malignant lesions), inhomogeneous (11 [61%] benign lesions, six [75%] malignant lesions), or peripheral (five [28%] benign lesions, no malignant lesions) of the 19 lesions assessed for a change in enhancement over time, seven (37%) showed an increase and two (11%) showed a decrease in signal intensity. The authors conclude that benign and malignant soft-tissue lesions could not be differentiated solely on the basis of enhancement (pattern, degree, or time course).     

Bamboo splinter: ultrasound localization

Ultrasound was used to identify and localize a 2-cm hyperechoic bamboo splinter in the wrist of a patient with persistent symptoms, 1 month after the initial injury, following an initial negative workup by clinical examinations and X–ray. Electronic Publication     

Hydatid disease of the soft tissues of the lower limb: findings in three cases

Three cases of hydatid disease are reported, all presenting as soft tissue lesions in the lower extremities. All three cases were studied with ultrasound (US), two with computed tomography (CT), and two with magnetic resonance (MR) imaging techniques. Two patients presented with multivesicular lesions which were considered diagnostic of hydatid disease. The third patient showed a lesion with a predominantly solid pattern, closely mimicking a soft-tissue neoplasm. US was not diagnostic, but MR outlined vesicular structures and a fibrous pericyst. Hydatid disease presenting in the soft tissues can therefore be diagnosed with confidence when it shows multi-vesicular lesions but MR may be the most useful imaging technique when a complex or solid pattern is present.     

Musculoskeletal ultrasound intervention: principles and advances

Ultrasound scan is an invaluable tool in the diagnosis and treatment of disorders of the musculoskeletal system. Core concepts that are common to most ultrasound-guided procedures are reviewed, including an in-depth discussion regarding the use of injectable corticosteroids. Various aspects of intra-articular, intratendinous, bursal, and ganglion cyst intervention are discussed and promising advances in the treatment of chronic tendon disorders are presented.     

Ultrasound during dissection of cadaveric specimens: a new method for obtaining ultrasound–anatomic correlations in musculoskeletal radiology

We report a new technique for ultrasound–anatomic correlations consisting of dissection of embalmed specimens during ultrasound examination. Our method consists of performing ultrasound during the different stages of dissection. The technique was developed by making observations of selected structures in two embalmed and two non-embalmed cadaver hands. The image quality was subjectively graded by consensus of two investigators, before and after denudation of the selected structures of the hand. As an example, the technique is demonstrated for the flexors at the metacarpophalangeal joint level, the extensor complex at the level of the proximal phalanx, and the dorsal hood of the second to fourth fingers. Before dissection the image quality in fresh specimens was graded moderate, and in embalmed specimens good. After dissection the image quality was good in fresh specimens and excellent in embalmed specimens. Our method is simple and does not require sophisticated material. Our results indicate that embalmed specimens could be better than non-embalmed specimens, because of the presence of artefacts in the non-embalmed specimens (gas deposits). The described methodology can yield excellent results regarding precise identification of different interfaces and structures, as observed at ultrasound.     

Spinal Ewing sarcoma: Misleading appearances

The plain radiographic and computed tomographic (CT) findings in two unusual cases of spinal Ewing sarcoma are reported. Radiographic features resembling neuroblastoma in one case and aneurysmal bone cyst in the other were present. These findings may be misleading and distinguishing characteristics in each case are discussed.     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Diagnostic value of gadopentetate dimeglumine for 1.5-T MR imaging of musculoskeletal masses: comparison with unenhanced T1- and T2-weighted imaging.

Three magnetic resonance (MR) imaging techniques (T1-weighted, T2-weighted, and T1-weighted gadopentetate dimeglumine--enhanced) were compared in 32 consecutive MR imaging studies of 26 patients with suspected musculoskeletal masses. T2-weighted images were superior to T1-weighted enhanced images with respect to detection and definition of lesions in 12% of cases (n = 4) and were equal in 88% of cases (n = 28). T2-weighted images were also superior to T1-weighted images in 38% of cases (n = 12). In no cases were T1-weighted enhanced images superior to T2-weighted images. In two cases, T1-weighted images were superior to both T1-weighted enhanced and T2-weighted images. The authors conclude that gadopentetate dimeglumine did not provide much value in lesion detection above that obtained with T2-weighted images. They also conclude that T1-weighted images were occasionally superior to T1-weighted enhanced images and T2-weighted images because of loss of definition between fat and lesion on the latter.     

Dynamic contrast-enhanced MR imaging of musculoskeletal tumors: Basic principles and clinical applications

The purpose of this article is to review the basic principles and clinical applications of dynamic contrast-enhanced MRI in the musculoskeletal system. This method of physiologic imaging provides clinically useful information by depicting tissue vascularization and perfusion, capillary permeability, and composition of the interstitial space. Different imaging, evaluation, and postprocessing techniques are described. The most important applications in the musculoskeletal system are identification of areas of viable tumor for biopsy, tissue characterization, and monitoring of preoperative chemotherapy. Practical guidelines for performing a dynamic contrast-enhanced MR examination are proposed.     

超声弹性成像在浅表软组织局灶性病变诊断中的应用

目的 探讨超声弹性成像技术在浅表软组织局灶性病变诊断中的临床应用价值.方法 收集在我院就诊并手术的浅表软组织局灶性病变65例,并对其行实时超声弹性成像检查,根据病灶软硬度不同进行评分,并与术后病理进行分析.结果 良性病灶超声弹性图中良性囊肿病变以红绿蓝相间为多,良性实质性病变以1～3分多见,而恶性病变以4～5分多见.两组病变的弹性评分情况比较差异具有统计学意义（P＜0.01）.以≥4分作为判断恶性病变的标准,其敏感度为84％,特异度为90％,准确率为88％.结论 超声弹性成像对浅表软组织局灶性病变良恶性病变的鉴别诊断提供有价值的信息.     

Low-grade fibromyxoid sarcoma: ultrasound and magnetic resonance findings in two cases

Low-grade fibromyxoid sarcoma is a rare, slow-growing, yet metastasizing neoplasm characterized by histopathological fibrous/myxoid zonal alternations, which occasionally display an intralesional multinodular appearance. We report on the radiological features of two cases of low-grade fibromyxoid sarcoma. Case 1 was a large ovoid mass with a well-defined margin in the thigh, showing the characteristic multiple, intralesional variable-sized nodules on high-frequency ultrasound (US) and magnetic resonance imaging (MRI), some of the nodules showing a target-like appearance. Case 2 was a dumbbell-shaped chest wall mass showing invasive features without the intralesional multinodular appearance on MRI. The gross radiological appearances of our two cases were somewhat dissimilar, but they shared a pattern of low/high signal zonal distinction without hemorrhage or necrosis within the masses on MRI.     

Magnetic resonance imaging of intramuscular myxoma with histological comparison and a review of the literature

Objective To evaluate the magnetic resonance (MR) features of intramuscular myxoma (IM) compared with its pathological findings.Design Two radiologists retrospectively reviewed records and imaging studies of patients with histologically proven IM. Two radiologists also analyzed by consensus all the MR studies (pre- and post-contrast T1-weighted and T2-weighted sequences) and a pathologist reviewed the available histological material.Patients Seventeen patients with 18 histologically proven IM were reviewed. Histological samples of 11 of these 18 tumors were available for pathological analysis.Results There were 14 women and three men, with a mean age of 58.9 years. IM involved predominantly the thigh (n=10). MR imaging showed well-circumscribed intramuscular masses, hypointense on T1-weighted and hyperintense on T2-weighted images. Eleven masses were homogeneous and seven slightly heterogeneous due to fibrous septa. Enhanced MR imaging demonstrated three different patterns: peripheral enhancement (n=1), peripheral and patchy internal enhancement (n=7) or peripheral and linear internal enhancement (n=4). Intratumoral cysts were detected in four masses. MR imaging showed the presence of a pseudocapsule (n=12), fat around the lesion (n=16) and peritumoral edema (n=16). Histologically, all the tumors were hypocellular, hypovascular and myxoid. Peripheral areas of collagenous fibers formed a partial capsule and IM often merged into surrounding muscular fibers. More cellular tumors and those with scanty myxoid stroma tended to show a more prominent internal enhancement.Conclusion IM shows several recognizable MR features which suggest its diagnosis.     

Small nodules (1-2 cm) in liver cirrhosis: characterization with contrast-enhanced ultrasound

Objective

To determine the diagnostic efficacy of arterial phase contrast-enhanced ultrasound (CEUS) for characterizing small hepatic nodules (1-2 cm) in patients with high-risk for hepatocellular carcinoma (HCC).

Materials and methods

Over 12 months, CEUS was performed in 59 patients at high-risk for HCC with small hepatic nodules (1-2 cm; mean, 1.5 cm). Based only on arterial phase (<45 s) vascular intensity and pattern, lesions were prospectively diagnosed as HCC if there was hypervascularity without known features of hemangioma. The diagnosis of HCC was made regardless of the presence or absence of washout. Verification of diagnosis was made by liver transplantation (n = 13), biopsy (n = 12), resection (n = 3) or clinical and imaging follow-up for at least 12 months (n = 31).

Results

At of the time of CEUS, the 59 nodules were diagnosed as HCC in 26 and benign lesions in 33, including 20 regenerative/dysplastic nodules (RN/DN), 11 hemangiomas, and 2 focal fat sparing. All 26 nodules with arterial phase hypervascularity without hemangioma-like features were HCC. However, CEUS misdiagnosed HCC as RN/DN in 4 cases with arterial iso- (n = 3) or hypovascularity (n = 1). CEUS correctly diagnosed all 11 hemangiomas. The sensitivity, specificity, and accuracy of CEUS for diagnosing HCC were 86.7, 100, and 93.2%.

Conclusions

Arterial phase vascular intensity and pattern of CEUS are highly accurate for the diagnosis of small (1-2 cm) HCC and hemangioma in liver cirrhosis. On CEUS, arterial phase hypervascularity without a hemangioma-pattern alone may be sufficient for diagnosis of small HCC. Infrequent iso/hypovascular HCC may erroneously suggest RN/DN necessitating biopsy or close follow-up.     

Cerebral ultrasound images in prenatal cytomegalovirus infection

Summary A male newborn with prenatal cytomegalovirus infection was referred for cranial ultrasound. The cranial ultrasound demonstrated areas of increased echogenicity in the thalamic and gray nuclei resembling a branched candlestick. Doppler technique located the branched candlestick along the thalamostriate arteries. This image is particularly interesting because to our knowledge it has never before been described in congenital cytomegalovirus infection, but only in congenital rubella.     

Ultrasound appearance of myositis ossificans

Ultrasonic evaluation of a soft tissue mass of the thigh was performed and suggested the diagnosis of myositis ossificans. Correlation with routine radiographic studies is made, as well as with the follow-up radiographic examination.     

肝移植术后肺部感染的多层螺旋CT表现

目的 探讨肝移植术后肺部感染多层螺旋CT(MSCT)表现及其临床诊断价值.方法 搜集529例肝移植患者的临床及CT检杳资料,对术后肺部感染的类型、发生时间及CT表现进行回顾性分析,组间比较采用x2检验.结果 529例肝移植术后肺部感染的发病率为32.9/(174/529),感染次数181次,病死率为9.8/(17/174);细菌感染、真菌或合并真菌感染、病毒或合并病毒感染发生率分别为17.2/(91例)、14.7/(78例)、2.3/(12例);肺部感染在术后30 d内、31～90、90 d以后3个时间段的构成比分别为64.6/(117例)、28.7/(52例)、6.6/(12例);45例行胸部CT检查,发现实变影32例、磨玻璃影22例,结节影10例,网格样影或线样影4例,各种征象在细菌感染及真菌感染间的发生率比较差异均无统计学意义(P＞0.05).结论 肝移植术后肺部细菌感染、真菌感染均常见,日常以混合感染形式发生,术后30 d内为高危时期,胸部 CT扫描能准确显示病灶的范围及特征,对于肺部感染的综合诊断有重要意义.