Contrast-enhanced sonography of the lung for differential diagnosis of atelectasis.

OBJECTIVE: Because of the absence of air in atelectatic tissue, sonography allows visualization of lung atelectasis and may characterize pulmonary and bronchial arterial vascularity by contrast-enhanced sonography (CES). METHODS: Thirty consecutive patients with obstructive atelectasis (OA) (n = 17) and compression atelectasis (n = 13) were retrospectively studied by CES using a second-generation sulfur hexafluoride contrast agent (SonoVue [BR1]; Bracco SpA, Milan, Italy). The following CES parameters were evaluated: (1) time to enhancement (TE) of the contrast agent after intravenous application was determined and classified as short TE and delayed TE (short TE, < or =6 seconds; versus delayed TE, >7 seconds); and (2) extent of enhancement (EE) was evaluated during the arterial phase (2-30 seconds) and the parenchymal phase (1-5 minutes): the EE of pleural lesions was determined in comparison with splenic enhancement and classified in reduced EE versus marked EE. RESULTS: All 13 patients with compression atelectasis had a short TE and a marked EE during arterial and parenchymal phases. In the remaining 17 patients with OA, 10 patients had a short TE and 7 patients had a delayed TE. The EE during both phases was reduced in 5 patients and marked in 3. Nine of 17 patients with OA had different EE during arterial and parenchymal phases. CONCLUSIONS: Compression atelectasis is characterized by CES with a short TE and a marked EE, indicating patent pulmonary arterial vascularization. In patients with OA, a variable CES pattern is found. With regard to only the TE, a delayed TE implies OA. This indicates a shifting of pulmonary vascularization to bronchial arterial vascularization in these patients.     

超声背向散射积分在肝占位性病变诊断中的应用价值

目的 :应用超声背向散射积分 (IBS)这一新技术对不同肝占位性病变的二维图像进行定量分析比较 ,评价该技术在肝占位性病变鉴别诊断中的应用价值。方法 :将肝占位性病变按病理分型分为肝囊肿组、肝血管瘤组、肝癌组。按回声强度分为无回声、低回声和强回声组。应用背向散射积分对各种肝占位性病变的二维图像及 IBS参数进行测定。结果 :肝囊肿组与肝血管瘤和肝癌组之间 AII、 PPI和 SDI均有显著性差异 (P<0 .0 1) ;肝血管瘤组与肝癌组之间 PPI、 SDI有显著性差异 (P<0 .0 1) ,AII无显著性差异 (P>0 .0 5) ;AII在无回声、低回声和强回声各组间均分别有显著性差异。随着回声的增强 ,AII值增大。结论 :背向散射积分在肝占位性病变鉴别诊断中有一定的价值     

Imaging of diseases of the thyroid gland in Austria

Imaging techniques for first line investigation of diseases of the thyroid gland are sonography (US) and scintigraphy, followed in dedicated cases by magnetic resonance imaging (MRI). Malignant lesions are generally hypoechoic on US with calcifications visible in some cases. The appearance of lymph node metastases is similar to that of the primary tumour. The various forms of goiter are the most commonly occurring forms of thyroid diseases in Austria, they appear heterogenous with hyperechoic as well as hypoechoic or anechoic nodes, in some cases with calcification. US findings of thyreoiditis are in acute forms of the disease more hypoechoic with diffuse swelling and hyperechoic with scar formations in chronic forms. Ectopic thyroid tissue occurs often in the form of thyroglossal duct cysts which are anechoic or hypoechoic.     

Sonographic approach to diagnosing pulmonary consolidation.

Thirty-nine consecutive patients with consolidated lung confirmed radiologically underwent sonography, and their sonograms were compared with results for 100 healthy subjects. The hyperechoic line of normal aerated lung and its air artifacts showed respiratory motions ("gliding sign," n = 100). Patients with pneumonia demonstrated distinct sonographic patterns. Strong linear echoes with characteristic air artifacts (air bronchogram) and anechoic tubular structures (fluid bronchogram) were visualized in 36 of 39 patients (92.30%). The superficial lung showed a homogeneous hypoechoic band termed "superficial fluid alveolograms" (n = 39) with respiratory motions in 35 of 39 patients. We conclude that sonography can evaluate pulmonary consolidation and may provide additional roentgenographic information, especially when fluid bronchograms are visualized.     

Hypoechoic normal renal sinus and renal pelvis tumors: sonographic differentiation.

OBJECTIVE: To evaluate the sonographic findings of an unusually hypoechoic renal sinus that mimics a tumor in the renal pelvis or renal sinus. METHODS: Sonographic scans of 7 patients with an unusually hypoechoic portion in the renal sinus were reviewed retrospectively. Computed tomography, excretory urography, or both confirmed all sinuses as normal. Five consecutive cases of renal pelvis tumors, which were detected on sonography initially in same period, were also reviewed to determine the differences between the 2 conditions. All cases were transitional cell carcinomas of the renal calyces. The images were analyzed for location, shape, margin, presence of posterior sonic attenuation, and associated findings such as caliectasis. RESULTS: Sonographic findings noted in patients with hypoechoic normal renal sinuses were irregular and poorly defined margins (n = 7), a central and symmetric location in the renal sinus (n = 6), the presence of posterior sonic attenuation with nonvisualization of the posterior border of the lesion (n = 7), an unaffected peripheral hyperechoic renal sinus (n = 7), and traversing hilar vessels in the lesion on color Doppler sonography (n = 7). In contrast, renal pelvis tumors had a relatively well-defined margin (n = 4), an eccentric location in the renal sinus (n = 2), a partially or completely obliterated hyperechoic renal sinus (n = 2), a visible posterior margin (n = 5), no posterior shadowing (n = 5), vessel displacement by the mass on color Doppler sonography (n = 5), and associated caliectasis (n = 1). CONCLUSIONS: By being familiar with the sonographic characteristics of a hypoechoic renal sinus, it can be differentiated from renal pelvis tumors, and unnecessary diagnostic workups can be avoided.     

The small spleen: sonographic patterns of functional hyposplenia or asplenia

PURPOSE: Functional hyposplenia or asplenia (FAS) can be associated with potential fatal infections. The diagnosis of FAS is traditionally made on liver-spleen scintigraphy and finding Howell-Jolly bodies within erythrocytes. In this retrospective study, our goal was to identify any characteristic sonographic findings of the spleen in patients with FAS in an attempt to determine whether the diagnosis of FAS can be made sonographically. METHODS: In a review of all medical and sonographic records from the period of January 1, 1985, through December 31, 2001, we identified 24 patients (11 men, 13 women) in whom FAS had been diagnosed by liver-spleen scintigraphy (n = 13) or the finding of Howell-Jolly bodies (n = 11). The following sonographic parameters were determined: size of spleen (small, normal, or large), echotexture of the spleen (homogeneous versus inhomogeneous), echogenicity (isoechoic versus hyperechoic), presence of focal splenic lesions, and patterns of splenic vascularization as determined by color Doppler sonography (absent flow, hilar flow, or parenchymal flow). RESULTS: The spleen was small in 20 patients (83%) and normal in the other 4 (17%). Echotexture was homogeneous in 13 patients (54%) and inhomogeneous in 11 (46%). The spleen was isoechoic in 18 cases (75%) and hyperechoic in 6 (25%). Six patients (25%) had focal lesions. Color Doppler sonography showed absent flow in 4 patients (17%), hilar flow in 17 (71%), and hilar and parenchymal vascularization in 3 (12%). CONCLUSIONS: Sonographic findings in the spleen of patients with FAS are characterized predominantly by a small spleen with absence of parenchymal vascularization on color Doppler sonography in most cases. Future prospective studies will be necessary to confirm these findings and to determine whether FAS can be diagnosed reliably with sonography.     

肉芽肿性小叶性乳腺炎超声表现

目的探讨肉芽肿性小叶性乳腺炎(GLM)的高频超声图像特征。方法对23例以乳腺包块就诊,经术前超声及手术病理证实为GLM患者的病例资料进行回顾性分析。在灰阶声像图上观察肿块大小、形状、边界、内部回声及后方回声。应用彩色多普勒血流成像(CDFI)观察病灶内部及其周围血流分布和供应情况。结果23例GLM患者(均经手术后病理证实)均为经产妇,年龄20～43岁。灰阶声像图显示12例表现为连续或不连续的不规则管状结构样低回声区,低回声区周围为高回声;5例表现为单发或多发、边界相对清楚、不均质低回声结节或肿块,其内可伴无回声区;5例表现为病变区腺体结构紊乱,未见明确边界,内部回声强弱不一,病变内可见无回声区;1例表现为边界模糊、形态不规则的低回声实质肿块伴后方回声衰减。23例中患处皮肤层增厚8例,6例伴有皮肤破溃,窦道形成。CDFI示22例(22/23)病变内部及周边动静脉血流信号明显增加。结论GLM病变的超声表现具有一定的特点,但这些表现不具有特征性,确诊仍需病理学检查。     

Differential diagnosis of focal epididymal lesions with gray scale sonographic, color Doppler sonographic, and clinical features.

OBJECTIVE: To determine whether focal epididymal lesions can be differentiated on gray scale sonographic, color Doppler sonographic, and clinical features. METHODS: This was a retrospectiveanalysis of 60 focal epididymal lesions in 57 patients. Focal epididymal lesions were classified into 3 groups: nonspecific epididymitis (n = 43), tuberculous epididymitis (n = 10), and benign epididymal masses (n = 7). The following gray scale sonographic, color Doppler sonographic, and clinical features were analyzed: size, location, echogenicity, and heterogeneity of the lesion; hypoechoic or hyperechoic rim presence; hydrocele presence; degree of blood flow in the lesion; patient's age; duration of symptoms; and scrotal tenderness. RESULTS: Lesions were larger in patients with tuberculous epididymitis than in those with either nonspecific epididymitis (P = .007) or benign epididymal masses (P = .0017). The hypoechoic or hyperechoic rim of the lesion was more common in patients with benign epididymal masses than in those with nonspecific epididymitis (P = .002). The degree of blood flow in the lesion was greater in patients with nonspecific epididymitis than in those with either tuberculous epididymitis (P = .0019) or benign epididymal masses (P < .001). The duration of symptoms was shorter in patients with nonspecific epididymitis than in those with either tuberculous epididymitis (P < .001) or benign epididymal masses (P = .0092). The frequency of scrotal tenderness was higher in patients with nonspecific epididymitis than in those with either tuberculous epididymitis (P < .001) or benign epididymal masses (P < .001). CONCLUSIONS: Gray scale sonographic, color Doppler sonographic, and some clinical features may be helpful for differential diagnosis of focal epididymal lesions.     

Unusual benign focal liver lesions: findings on real-time contrast-enhanced sonography.

OBJECTIVE: This presentation aims to provide an overview of the manifestations of some unusual benign focal liver lesions (FLLs) on low-acoustic power contrast-enhanced sonography (CES) with a sulfur hexafluoride contrast agent. METHODS: The patients were selected retrospectively from 2209 cases with FLLs who had undergone CES examinations for characterization during the past 3 years. The pathologic examinations proved that they were intrahepatic biliary cystadenoma (n = 1), angiomyolipoma (AML; n = 4), lipoma (n = 1), biliary epithelial dysplasia (n = 1), a fungal inflammatory mass (n = 1), tuberculoma (n = 2), an inflammatory pseudotumor (n = 7), sarcoidosis (n = 1), solitary necrotic nodules (n = 2), peliosis hepatis (n = 2), and focal fibrosis after surgery (n = 4). RESULTS: Contrast-enhanced sonography was beneficial in leading to a diagnosis of benignity for some lesions showing hyperenhancement during the arterial phase and sustained enhancement during the portal or late phase, such as liver AML and lipoma. The benign nature of other lesions showing no enhancement during all phases, such as solitary necrotic nodules and focal fibrosis, was also suggestible. On the other hand, for those lesions showing hyperenhancement, isoenhancement, or hypoenhancement during the arterial phase and hypoenhancement during the late phase, including intrahepatic biliary cystadenoma, biliary epithelial dysplasia, infected liver diseases, the inflammatory pseudotumor, sarcoidosis, and peliosis hepatis, the differential diagnosis between benignity and malignancy was difficult, and pathologic tests were mandatory. CONCLUSIONS: The CES features of unusual benign FLLs may enrich knowledge when performing CES examinations for characterization and may provide clues for a specific diagnosis of an individual lesion such as liver AML.     

Clinical and sonographic findings in carcinoma of the penis

PURPOSE: This study was performed to assess the accuracy of high-resolution sonography in measuring penile carcinoma. METHODS: Sonography was performed using a 7.5-MHz linear-array transducer in 59 patients with penile carcinoma. The sonographic measurement of tumor extent was compared with clinical and pathologic measurements. The tumor extent measured by gross pathologic evaluation on cut sections of the fresh penectomy specimen was used as the definitive standard. The echogenicity of the tumor was compared with that of the surrounding normal penile tissue to classify the tumor as hyperechoic, hypoechoic, or of mixed echogenicity (containing both hyperechoic and hypoechoic elements). We evaluated the relationship between the echogenicity of the tumor and both tumor morphology (exophytic or infiltrative) and tumor grade as determined on pathologic examination. RESULTS: The overall mean difference +/- standard deviation in the tumor extent between clinical and gross pathologic evaluation was 3.9 +/- 5.3 mm (range, 1-9 mm), whereas the overall mean difference between sonographic and gross pathologic evaluation was 1.2 +/- 1.7 mm (range, 1-7 mm). As determined with reference to the gross pathologic extent, the error in measuring the extent on clinical examination was significantly greater than the error on sonography (p < 0.001). Lesions involving the glans alone were more often underestimated by clinical examination than were lesions involving the shaft (with or without glanular involvement). The error in measuring the extent of tumor by sonography was not related to the site of the tumor. The tumor was hyperechoic in 21 cases (36%), hypoechoic in 28 cases (47%), and of mixed echogenicity in 10 cases (17%). There was no significant association between echogenicity and tumor morphology or grade. CONCLUSIONS: Sonography gives a more accurate estimate of penile tumor extent than does physical examination. Routine use of sonography for such measurements should enable preservation of more of the penis.     

Tuberculosis of the parotid gland: sonographic manifestations and sonographically guided aspiration.

OBJECTIVE: Involvement of the parotid gland by tuberculosis (TB) is rare. If treated properly, the prognosis of TB of the parotid gland is good. In this retrospective study, we report our experience with sonography and sonographically guided aspiration in the diagnosis of parotid TB. METHODS: Over 12 years, 9 adults (mean age, 48 years) with parotid gland TB had been examined with high-resolution sonography and color Doppler sonography for their clinical problems of swelling on the mandibular angle. Sonographically guided fine-needle aspiration was done for cytologic study, stains for acid-fast bacilli, and cultures for mycobacterium. RESULTS: The sonographic patterns were classified as chiefly the parenchymal type (4 patients) and chiefly the periparotid type (5 patients). The parenchymal type appeared as a diffusely enlarged, comparatively hypoechoic gland (compared with the contralateral asymptomatic gland), with or without focal intraparotid nearly anechoic zones, which might have a cavity or cavities within it. The periparotid type appeared as hypoechoic nodules located in the peripheral zone of the hyperechoic parotid gland, consistent with enlarged periglandular lymph nodes. The diagnosis of parotid TB was made in 8 of 9 patients on the basis of sonographically guided aspiration for acid-fast bacilli stains, cytologic study, and cultures for mycobacterium. CONCLUSIONS: Sonographic examination contributes substantially in the diagnosis of parotid TB infection. In the presence of diffuse parotid echo pattern changes with periparotid lymphadenopathy, and with or without focal hypoechoic zones, TB infection should be differentiated. Sonographically guided fine-needle aspiration may provide further diagnostic information by means of stains, cultures, and cytologic study.     

Hurthle cell neoplasms of the thyroid: sonographic appearance and histologic characteristics

OBJECTIVE: The purpose of this study was to determine the sonographic features of Hürthle cell neoplasms (HCNs) of the thyroid. METHODS: We retrospectively analyzed the sonographic appearance of 15 histologically proven HCNs in 15 patients aged 16 to 70 years (mean age, 44 years). Sonographic features that were reviewed included the size and echogenicity of the tumors, the presence of cystic areas or calcifications, and detectable blood flow on color Doppler imaging. Correlation of sonographic findings with pathologic results was performed. RESULTS: The tumors ranged from 0.4 to 7 cm in diameter, but most were less than 3 cm in diameter. Four (27%) of the 15 tumors were homogeneously hypoechoic. Two tumors (13%) were predominantly hypoechoic with isoechoic areas to thyroid parenchyma. Two (13%) neoplasms were isoechoic to thyroid parenchyma. Four (27%) tumors were predominantly isoechoic, containing hypoechoic areas, and 3 (20%) tumors were hyperechoic. Three neoplasms contained cystic components. None of the tumors contained calcifications. One tumor was avascular on Doppler examination. One neoplasm showed only peripheral blood flow. Thirteen tumors showed internal vascularity, 7 of them with peripheral blood flow. Twelve HCNs were benign, and 3 were malignant on pathologic examination. CONCLUSIONS: Hürthle cell neoplasms show a spectrum of sonographic appearances from predominantly hypoechoic to hyperechoic lesions and from peripheral blood flow with no internal flow to extensively vascularized lesions. Pathologic criteria differentiating benign and malignant HCNs (absence or presence of a capsular breach, vascular or extrathyroidal tissue invasion, nodal involvement, and distant metastasis) are beyond the resolution of sonography and fine-needle aspiration biopsy and require removal of the entire lesion. This precludes diagnosis and characterization of HCNs by sonography.     

Peripheral cholangiocarcinoma: sonographic evaluation.

One hundred and seven patients who had intrahepatic tumor that demonstrated by sonography, and proved histologically, to be cholangiocarcinoma (CC), were reviewed retrospectively. Two main tumor patterns were found, namely the nodular form (N = 101) and the infiltrative form (N = 6); 33 of 101 patients with nodular lesions had solitary masses and 18 had multiple masses. The echogenicity of primary tumors were hyperechoic (N = 56), hypoechoic (N = 15), isoechoic (N = 10), and mixed-echoic (N = 20). A peripheral hypoechoic rim was present in 35 primary tumors (34.7%). Peripheral bile duct dilatation was seen in 33 patients (30.8%). Extrahepatic extension was found at operation in 46 of 52 patients (88.5%), while it was demonstrable by ultrasonography in only 16 (30.8%). Five of 6 small lesions (3 cm and less) already had an extrahepatic extension.     

Bronchioloalveolar carcinoma: sonographic pattern of 'pneumonia'.

BACKGROUND: the sonographic pattern of bacterial pneumonia is predominantly well known and characterized by an air bronchogram, a marked vascularity on color Doppler sonography, and a high-impedance arterial flow pattern on Doppler spectral analysis. METHODS: in a retrospective study the sonographic findings in seven patients with peripheral BAC on X-ray examination were evaluated in relation to number, size, margins, echomorphology and sonographic arterial flow patterns of the lesions. RESULTS: the following sonomorphologic characteristics were found: multiple foci (n=4), single foci (n=3), smooth margins (n=5), irregular margins (n=2) and maximal diameter of size (range 5-15 cm). The echomorphology of the lesions was homogenously hypoechoic (n=1) or showed airbronchograms (n=6). Color Doppler sonography revealed a vascular tree pattern (n=5) or a marked presence of blood vessels (n=2). Doppler flow spectral analysis of arteries in investigated patients (n=5) demonstrates a high impedance (triphasic) flow pattern in four patients and a low impedance (monophasic) flow pattern in one patient. CONCLUSIONS: these findings indicate that BAC frequently shows a sonographic pattern of 'pneumonia'.     

Focal hepatic fatty infiltration as a cause of pseudotumors: ultrasonographic patterns and clinical differentiation

Focal hepatic fatty infiltration may be mistaken for hepatic neoplasm on ultrasonography. A sonographic feature mimicking "space occupying lesions" was identified in 41 cases with focal fatty liver, which led to the recognition of four sonographic patterns: (1) Ten patients in whom the livers were characterized by irregular configurations of hyperechoic and hypoechoic areas. Although confusing to inexperienced sonographers, all of them were properly interpreted by experienced sonographers. (2) One patient in whom the hepatic sonography revealed a hyperechoic nodule, but which was correctly diagnosed by computed tomography (CT) scan. (3) Six patients in whom the livers were characterized by multiple confluent hyperechoic lesions, which were all misinterpreted by sonographers and misinterpreted following CT scans in 4 cases and angiography in 3 cases. (4) Twenty-four patients in whom the livers revealed focal spared areas, which was misdiagnosed by sonographers in 14 cases, but correctly diagnosed by CT scan in all 24 cases.     

Ruptured abdominal aortic aneurysm: categorization of sonographic findings and report of 3 new signs.

OBJECTIVE: The purpose of this study was to categorize the sonographic findings seen in patients with a ruptured abdominal aortic aneurysm (AAA) and to describe 3 previously undescribed sonographic findings. METHODS: From January 1997 to December 2003, we evaluated 388 consecutive patients with an AAA (transverse aortic diameter >30 mm). Among these patients, 29 had surgical or computed tomographic demonstration of aneurysm rupture. The remaining 359 were asymptomatic and had no evidence of AAA rupture at follow-up. RESULTS: Findings recognized among 29 positive cases included AAA deformation (n = 12), luminal thrombus inhomogeneity (n = 20), clear interruption of a luminal thrombus (n = 5), retroperitoneal hematoma (n = 22), and hemoperitoneum (n = 11). In addition, 3 previously unreported findings were noted: an intraluminal floating thrombus layer (n = 8), a parietal hypoechoic focus due to aneurysm wall interruption (n = 3), and a para-aortic hypoechoic area adjacent to the bleeding side (n = 4). Aside from AAA deformation and thrombus heterogeneity, no other signs were recognized among subjects with a nonruptured aneurysm. CONCLUSIONS: In the past, sonography has been used mainly to rapidly confirm aneurysm presence in the clinical setting of a patient with a suspected rupture. Instead, this retrospective series shows how this imaging technique can frequently identify several direct and indirect signs of aneurysm rupture itself. Moreover, 3 new indicators of AAA rupture have been observed.     

Multiparametric Sonography of Testicular Hematomas

We investigated the appearances of intratesticular hematomas on multiparametric sonography combining grayscale, color Doppler, and contrast‐enhanced sonography and strain elastography. Over a 3‐year period, 17 hematomas in 8 patients were analyzed. Blunt trauma (n = 7) and surgery (n = 1) were preceding events. Grayscale sonography showed well‐defined oval or round predominantly hypoechoic and heterogeneous, peripherally (n = 13) or centrally (n = 4) located lesions. Three showed contrast enhancement of septations, and 4 showed peripheral lesion rim enhancement. On strain elastography, the mean strain ratio was 1.19 (range, 0.41–2.36), and elasticity score were 3 or lower (n = 13) and 5 (n = 4). Multiparametric sonography shows nonenhancement with contrast and predominantly “soft” elastographic properties and aids in the interpretation of the benign nature of intratesticular hematomas.     

Sonographic patterns in splenic infarct

The sonographic findings in eight cases of splenic infarct at their onset and at different phases of their development have been retrospectively analyzed. A wide range of appearances was seen (single or multiple, rounded or wedge-shaped, echo-free, hypoechoic, and hyperechoic lesions). In our opinion, such variable appearances are related to the age of the infarct (hypoechoic or echo-free in the earlier stages, hyperechoic in healed infarcts). A presumptive diagnosis is possible in the earlier stages since the detection of changes (in echogenicity and/or in size) over a period of time strongly suggests an infarct. On the other hand, a hyperechoic wedge-shaped lesion is fairly typical of healed infarcts.     

桥本氏甲状腺炎的超声诊断与鉴别诊断

目的探讨桥本氏甲状腺炎(HT)的二维及彩色多普勒超声表现及鉴别要点。方法60例HT患者及82例甲状腺其他疾病患者应用常规超声检查,分析其声像图表现及超声鉴别要点。结果按回声分类,HT可分为四型:局灶性回声减低型、弥漫性回声减低型、单发结节型及多发结节型。与甲状腺其他疾病比较,各型HT特征性的变化有峡部增厚,双侧叶对称性肿,不规则强回声带,结节呈实性、斑点状钙化,结节外血流信号丰富及双侧甲状腺上动脉PSV值对称性升高。结论二维及彩色多普勒超声对HT的诊断及鉴别诊断有重要价值。     

Mature mediastinal teratoma: sonographic imaging patterns and pathologic correlation.

OBJECTIVE: To characterize the sonographic patterns of teratomas located within the mediastinum and to correlate them with pathologic findings, because there have been few reports concerning the application of sonography in the diagnosis of mediastinal teratoma. METHODS: Over a 9-year period, we carried out an image analysis of the sonographic findings of 28 mediastinal teratomas whose diagnoses were proved surgically. RESULTS: Sonography showed that 18 patients had a complex mass of heterogeneous echogenicity, including regional bright echoes (n = 12), acoustic shadows (n = 8), hyperechoic lines and dots (n = 7), soft tissue septa (n = 9), dermoid plugs (n = 6), and hypoechoic areas (n = 11). This type of mediastinal teratoma revealed, in pathologic findings, varying combinations of fat, sebaceous and mucinous materials, hair, mineralized elements, and multiple compartments. Eight patients had a homogeneous hyperechoic mass, and the 2 remaining patients had floating spherules within a cystic mass. Pathologically, the homogeneous mass mainly contained hair and sebaceous material. The floating spherules were also composed of sebaceous tissue and were above the fluid of the cyst. CONCLUSIONS: On the basis of the evaluation of the sonographic and pathologic findings, we described 3 major patterns of mediastinal teratoma: a complex mass of heterogeneous echogenicity, homogeneous high echogenicity within a solid mass, and floating spherules within a cystic mass. Thus, sonography can improve the diagnosis of mediastinal teratoma. However, additional prospective studies are needed to test the sensitivity and specificity of these sonographic patterns in the diagnosis of mediastinal teratoma.