CT and MR imaging findings of benign cardiac tumors

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rare, benign tumors outnumber their primary malignant counterparts three to one. Since mortality varies directly with invasion, identifying the neoplasm at an early stage helps focus treatment, especially in benign cases, which generally respond well to surgical resection. In adults and children, myxomas and rhabdomyomas, respectively, represent the most common benign tumors, which can be grouped into tissue-specific subtypes, such as rhabdomyomas, fibromas, lipomas, teratomas, etc. Besides their variable prevalence in particular age groups, these tumors also differ with regard to their gender predilection, location, and number. For example, myxomas appear predominantly in women and generally as a solitary mass in the left or right atrium, whereas rhabdomyomas present equally in boys and girls and chiefly as multiple masses in the ventricles. Despite their differences, however, both types share an association with heritable syndromes like the Carney complex for myxomas and tuberous sclerosis for rhabdomyomas. As with all cardiac tumors, echocardiographic findings usually suggest the initial diagnosis but cross-sectional imaging with CT and MRI can help resolve diagnostically challenging cases. For example, with its direct multiplanar capability, excellent contrast resolution, and large field of view, MRI permits a detailed examination of the entire mediastinum, helping to rule out an equivocal mass on echocardiography. Through dynamic techniques, MRI, in addition to morphologic characterization, can depict the pathophysiological effects of these tumors, for instance, with regard to myocardial contraction, valvular function, or blood flow.     

Pancreatic adenocarcinoma

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head of the pancreas in 60–70% of cases. By the time of diagnosis, at least 80% of tumors are unresectable. Helical computed tomography (CT) is very effective in detecting and staging adenocarcinoma, with a sensitivity of up to 90% for detection and an accuracy of 80–90% for staging, but it has limitations in detecting small cancers. Moreover, it is not very accurate for determining nonresectability because small liver metastases, peritoneal carcinomatosis, and subtle signs of vascular infiltration may be missed. Multidetector-row CT (MDCT) has brought substantial improvements with its inherent ability to visualize vascular involvement in three dimensions. MDCT has been found to be at least equivalent to contrast-enhanced magnetic resonance imaging (MRI) for detecting adenocarcinoma. MRI can be used as a problem-solving tool in equivocal CT: MRI may help rule out pitfalls, such as inflammatory pseudotumor, focal lipomatosis, abscess, or cystic tumors. Mangafodipir-enhanced MRI reveals a very high tumor-pancreas contrast, which helps in diagnosing small cancers. Endosonography is, if available, also a very accurate tool for detecting small cancers, with a sensitivity of up to 98%. It is the technique of choice for image-guided biopsy if a histologic diagnosis is required for further therapy.     

Hallazgos de imagen de las masas cardíacas (parte II): tumores malignos y lesiones pseudotumorales

Malignant heart tumors are less common than benign ones. They can be primary or secondary. Secondary or metastatic heart tumors are 20 to 40 times more common than primary malignant heart tumors, which have an estimated incidence of 0.05%. Non-neoplastic pseudotumors can present as cardiac masses, with imaging characteristics than can suggest the diagnosis of a tumor. The aim of this article is to describe and illustrate malignant heart tumors and pseudotumors, stressing the CT and MRI findings that make it possible to differentiate them from benign cardiac tumors.     

腮腺肿瘤的CT及MRI诊断及鉴别诊断

目的：探讨腮腺肿瘤的CT及MRI表现,旨在提高对腮腺肿瘤的诊断水平。方法：回顾性分析经病理证实的90例腮腺肿瘤的CT及MRI的表现。结果：90例腮腺肿瘤中,良性肿瘤74例（82.2%）,恶性肿瘤16例（17.8%）。在CT/MRI上,良性肿瘤大部分表现为位于腮腺浅叶的圆形、椭圆形软组织肿块,边缘光整,密度/信号均匀;而恶性肿瘤,大部分位于腮腺深叶或跨叶,表现为不规则形软组织肿块,边缘不清,密度/信号不均匀,侵犯周围组织并伴淋巴结转移。结论：CT和MRI检查均能对腮腺肿瘤进行有效定位,并对诊断及鉴别诊断具有一定价值。     

Osteosarcoma of the lumbosacral spine invading the central venous pathways,right-sided cardiac chambers,and pulmonary artery

We report an unusual case of lumbosacral osteogenic sarcoma with cauda equina syndrome and invasion into the central venous and cardiac system. A 41-year-old Hispanic man presented to the emergency department complaining of severe low back pain, cauda equina syndrome, bilateral lower extremity edema, and an extra heart sound on physical examination. CT of the lumbosacral spine done in the emergency department demonstrated a sclerotic lesion in the sacrum with cortical destruction, extension into the spinal canal and a bulky soft tissue mass containing calcifications. Supplemental MRI demonstrated marrow replacement of L4, L5, and the sacrum, soft tissue extension of the tumor, and invasion iliac veins extending into the IVC; however, the full extent of the intravascular tumor was not seen on this examination. Surgical laminectomy and biopsy of the spinal tumor provided the diagnosis of osteogenic sarcoma. A transthoracic echocardiogram was performed while the patient was recovering due to nonsustained ventricular tachycardia, which showed an echogenic mass within the right atrium and ventricle. CT pulmonary angiogram confirmed the echocardiogram showing a tumor extending through the pulmonary valve into the main pulmonary artery. The patient underwent en bloc resection of the tumor from the venous and cardiac systems. Histologic examination of the tumor confirmed osteogenic sarcoma. While vertebral osteogenic sarcoma is uncommon, invasion of the spinal canal is common in these tumors. However, tumor extending into the central venous and cardiac system is rare. The previously reported cases of central venous and cardiac involvement have been related to distant metastases or primary cardiac osteosarcomas. There is only one other reported case of direct extension into the venous system by an iliac bone osteosarcoma in an adolescent; however, the tumor did not extend into the pulmonary circulation.     

腹膜后良性神经鞘瘤的影像学特征

目的分析腹膜后良性神经鞘瘤的 CT 和 MRI 表现,总结其影像学特征.资料与方法经手术病理证实的27例腹膜后良性神经鞘瘤患者中,21例行多层螺旋 CT 检查,9例行 MRI 检查.观察 CT、MRI 平扫和增强时肿瘤的特征性改变.结果27例腹膜后良性神经鞘瘤边缘规则光整,直径多在5~10cm之间,CT 平扫肿瘤呈实性或囊实性.CT 增强后动脉期轻至中度强化10例,主要呈云絮状、索条状强化;动脉期9例可见纤细血管显影.门脉期及延迟扫描轻度渐进性强化13例.MRI 平扫呈不均匀长 T1长 T2影,DWI 呈高信号,4例可见靶征改变,增强后门脉期及延迟呈渐进性强化.无一例发生淋巴结转移.结论腹膜后良性神经鞘瘤影像学表现具有一定特异性,CT 结合 MRI 检查及多期增强扫描对其诊断有一定价值.     

原发性肾上腺恶性肿瘤的CT、MRI评价

目的探讨CT和MRI对原发性肾上腺恶性肿瘤的诊断及鉴别诊断价值. 资料与方法对26例经手术和病理证实的原发性肾上腺恶性肿瘤的CT、MRI表现进行回顾性分析,包括肾上腺皮质癌17例,恶性嗜铬细胞瘤7例,原发性恶性淋巴瘤、恶性间皮瘤各1例. 结果 CT和MRI定位准确性分别是86%和95%,定性的准确性为90%和95%.原发性肾上腺恶性肿瘤CT、MRI扫描的典型表现为肿瘤体积较大（直径〉5.0 cm）,形态不规则,边界不清或侵犯周围结构,内部结构不均匀,内有不规则坏死区或出血灶,增强后肿瘤呈不均一明显强化;77%（20例）肿瘤侵犯周围结构和/或远处转移. 结论 CT、MRI能诊断大部分原发性肾上腺恶性肿瘤,并确定其侵犯范围,两者对原发性肾上腺恶性肿瘤的诊断价值相似,后者有利于肿瘤的定位.     

原发性心脏心包肿瘤的MRI诊断

目的；评价MRI在原发性心脏心包肿瘤诊断中的价值。资料与方法：回顾分析14例经手术病理或临床证实的原发性心脏心包肿瘤的MRI表现，并与ICG检查结果比较。结果：除1例右心房粘液瘤漏诊，1例定位错误外，其余定位和良恶性定性均正确，10例术前组织学定性正确，与MRI比较，UCG另有3例定位定性错误，结论：MRI对心腔内肿瘤不仅定位准确，还多可定性；对肌壁肿瘤的良，恶性区别也有重要价值。对心包肿瘤多因其好发部位与特殊信号诊断不难，MRI是诊断和评价原发性心脏心包肿瘤重要的影像检查方法。     

脑室内肿瘤的CT和MR诊断及鉴别诊断

目的 :评价和探讨脑室内肿瘤的CT和MR诊断价值。方法 :经手术病理证实的脑室肿瘤 32例 ,回顾性分析其CT和MR表现。结果 :脑室肿瘤与发病年龄和发病部位关系密切并且具有一定影像特征。CT显示肿瘤钙化较佳 ,对肿瘤的鉴别诊断帮助很大。MR可以三维成像 ,可以准确显示肿瘤的位置及邻近情况。结论 :脑室肿瘤的诊断主要依靠其CT和MR表现 ,结合年龄特征和发病部位 ,可进一步提高诊断准确率。     

胸膜以外部位孤立性纤维瘤的CT和MRI影像分析

目的:探讨胸膜以外部位孤立性纤维瘤(ESFT)的CT和MRI表现及病理学特征,提高对本病的认识及诊断水平.方法:回顾性分析7例ESFT的CT和MRI表现度病理学表现.结果:本组ESFT的主要CT表现为略低密度软组织肿块.主要MRI表现为T1WI上肿瘤呈低信号～稍高信号,T2 WI上呈等信号或稍高信号.增强扫描示早期肿瘤...     

儿童后颅凹肿瘤的CT, MRI诊断

目的：分析儿童后颅凹常见肿瘤的ＣＴ和ＭＲＩ影像学表现,提高诊断该病的准确性。材料和方法：收集儿童后颅凹常见肿瘤４０例,其中髓母细胞瘤１８例,星形细胞瘤１３例,室管膜瘤９例。行ＣＴ和ＭＲＩ检查。ＣＴ平扫４０例,增强扫描３２例;ＭＲＩ平扫２８例,增强扫描１６例。将其结果与手术病理对照。结果：４０例儿童后颅凹常见肿瘤ＣＴ显示率为９７５％,ＭＲＩ显示率为１００％。术前ＣＴ定性误诊１１例,准确率为７２５％。术前ＭＲＩ定性误诊４例,准确率为８５７％。ＣＴ和ＭＲＩ联合检查,能对后颅凹多数常见肿瘤作出定位及定性诊断。ＭＲＩ能多方位成像,去除后颅凹颅骨伪影的干扰,对该病的定位定性诊断明显优于ＣＴ。结论：ＣＴ和ＭＲＩ检查相结合,能提高诊断儿童后颅凹常见肿瘤的准确率,为临床提供更准确的诊疗信息。     

侧脑室肿瘤的CT、MR诊断

目的 分析侧脑室肿瘤的CT与MRI影像学特征,提高对侧脑室各种肿瘤的诊断准确性。资料与方法 回顾性分析25例经手术与病理证实的侧脑室肿瘤的CT与MRI表现,其中CT检查5例,MRI检查7例,13例同时行CT和MRI检查。结果 25例中,脑膜瘤6例,室管膜瘤5例,星形细胞瘤4例,转移瘤3例,脉络丛乳头状瘤、中央性神经细胞瘤、室管膜囊肿各2例,室管膜下巨细胞瘤1例。CT显示肿瘤钙化较佳,MR定位准确性高,可以准确显示肿瘤的位置及邻近情况。结论 不同种类的侧脑室肿瘤与发病部位、患者年龄有一定的关系,结合发生部位和年龄特征,可提高诊断率。     

Imaging findings in myomatous angiomyolipoma of the liver

Angiomyolipoma of the liver is a rare benign mesenchymal tumor, comprising three tissue components: blood vessels, smooth muscles, and adipose cells. Depending on the predominance of these components, tumors are categorized into various types, out of which the myomatous variant is the most rare. Most of these tumors are detected incidentally and are solitary when discovered. Definitive preoperative diagnosis is often difficult because the radiological appearance of hepatic angiomyolipoma can be non-specific and varied. This is because the distribution and relative proportion of the three tissue components vary widely from tumor to tumor. Here, we present ultrasonography (US), multidetector computed tomography (CT), and magnetic resonance imaging (MRI) findings with pathological correlations of myomatous angiomyolipoma of the liver in a 21-year-old asymptomatic man who had no history of liver disease, hepatitis, or tuberous sclerosis. The tumor was hypoechoic on US and showed wash-in in the arterial phase and wash-out in the portal-venous phase on both dynamic contrast-enhanced CT and MRI. Additionally, the lesion was hypointense in the hepato-biliary phase on MRI obtained two hours after gadobenate dimeglumine administration and was not clearly identified from fat tissue in the in-phase/opposed-phase T1-weighted sequences.     

MRI of islet cell tumors of the pancreas

OBJECTIVE: CT is the most widely used imaging technique for the diagnosis of islet cell tumors, but MRI may be better for detecting small lesions and metastases because of its optimal contrast resolution and ability to easily perform dynamic imaging. The purpose of this pictorial essay is to highlight the MRI features of these tumors and underscore potential pitfalls. CONCLUSION: Although classically considered well-defined, arterially enhancing lesions that are bright on T2-weighted sequences, pancreatic islet cell tumors have quite a broad spectrum of appearances. MRI is well suited for detecting and characterizing pancreatic islet cell tumors as well as their local effects and metastases.     

输尿管恶性肿瘤的影像学诊断

目的：探讨输尿管恶性肿瘤的影像学表现，提高对该病的诊断水平。方法：选择过去5年经手术和病理证实的12例输尿管恶性肿瘤患者，回顾性分析其静脉尿路造影、US、CT和MRI表现，并与手术及病理结果进行对照。结果：CT与MRI准确地检出了所有12例肿瘤，对其向周围组织的浸润范围和腹腔淋巴结肿大也作了正确的判断。静脉尿路造影仅显示3例输尿管狭窄或梗阻，6例患侧尿路未见显影或显影不佳。尽管US检出了所有12例肿瘤所致的尿路积水，但仅2例诊断为输尿管肿瘤，4例提示输尿管狭窄。结论：CT和MRI对诊断输尿管恶性肿瘤有很高的敏感性，并能对其准确分期。尿路造影和US对肿瘤所致的输尿管狭窄和梗阻有一定的诊断价值，但通常不能直接显示肿瘤及其向周围组织的浸润。     

Pancreas. Part II: Tumors

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head in 60-70% of cases. By the time of diagnosis, approximately 80% of tumors are unresectable. Helical CT is very effective in detection and staging of adenocarcinoma, with a sensitivity of 76-92% for detection and an accuracy of 80-90% for staging, but it has limitations in the detection of small cancers (< or =2 cm). Multidetector CT (MDCT) has brought substantial improvements with its inherent 3D imaging capability. Mangafodipir-enhanced MRI is a problem-solving tool in the depiction of small cancers following an equivocal CT imaging result. Gadolinium-enhanced 3D gradient-echo MRI is helpful in the assessment of vascular invasion of cancer and in determining the etiology of cystic lesions. Serous cystadenoma is benign, has a lobulated contour and contains innumerable small cysts of 0.1-2 cm in diameter. Mucinous cystic neoplasms are unilocular or multilocular (fewer than six cysts), and the cyst diameter exceeds 2 cm. The presence of solid nodular components should alert the radiologist to suspect cystadenocarcinoma. Neuroendocrine tumors are mostly hypervascular. Diagnosis of insulinoma is a challenge: they are <2 cm in 90% of cases and mostly hypervascular at CT or MRI. A combination of contrast-enhanced MDCT, MRI, endosonography, and/or somatostatin receptor scintigraphy is used to detect these small tumors. This review summarizes the imaging features of the most common pancreatic tumors and discusses the limitations of CT, MRI and endosonography.     

Pankreas

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head in 60–70% of cases. By the time of diagnosis, approximately 80% of tumors are unresectable. Helical CT is very effective in detection and staging of adenocarcinoma, with a sensitivity of 76–92% for detection and an accuracy of 80–90% for staging, but it has limitations in the detection of small cancers (≤2 cm). Multidetector CT (MDCT) has brought substantial improvements with its inherent 3D imaging capability. Mangafodipir-enhanced MRI is a problem-solving tool in the depiction of small cancers following an equivocal CT imaging result. Gadolinium-enhanced 3D gradient-echo MRI is helpful in the assessment of vascular invasion of cancer and in determining the etiology of cystic lesions. Serous cystadenoma is benign, has a lobulated contour and contains innumerable small cysts of 0.1–2 cm in diameter. Mucinous cystic neoplasms are unilocular or multilocular (fewer than six cysts), and the cyst diameter exceeds 2 cm. The presence of solid nodular components should alert the radiologist to suspect cystadenocarcinoma. Neuroendocrine tumors are mostly hypervascular. Diagnosis of insulinoma is a challenge: they are <2 cm in 90% of cases and mostly hypervascular at CT or MRI. A combination of contrast-enhanced MDCT, MRI, endosonography, and/or somatostatin receptor scintigraphy is used to detect these small tumors. This review summarizes the imaging features of the most common pancreatic tumors and discusses the limitations of CT, MRI and endosonography.     

Articular and periarticular tumors: differential diagnosis using magnetic resonance imaging

Most patients with articular or periarticular tumors present with chronic monoarthritis and nonspecific alterations on laboratory tests; thus, it is important to know the changes on magnetic resonance imaging (MRI) that can suggest their diagnosis and the differential diagnosis of these tumors. MRI defines the anatomic origin and the tissue characteristics of articular and periarticular tumors, making it possible to reach a specific diagnosis in most cases. It is important to evaluate the MRI findings together with the plain-film findings because this helps in the characterization of mineralized tumors.     

颈部外周神经源性肿瘤的影像学诊断

目的：探讨颈部外周神经源性肿瘤的影像学表现及其诊断价值。资料与方法：33例颈部外周神经源性肿,包括神经鞘瘤28例，恶性神经鞘瘤2例，神经纤维瘤3例。26例行CT扫描，4例行MRI扫描，3例同时行MRI和CT扫描。结果：颈部外周神经源性肿瘤因发生在特定的解剖部位，易于辨认，依据肿瘤引起的骨质缺损或附近间隙，肌内，血管等移位方向，还可推测出它来自于哪一组神经。神经鞘瘤病理上有不同成分组成，故在影像学上多呈不均匀低密度（低信号）肿块，增强后不均匀现象更明显。根据这一现象可作出定性诊断。结论：CT和MRI扫描是诊断该肿瘤的有效方法。     

Atypical squamous cell carcinoma of the larynx and hypopharynx: radiologic features and pathologic correlation

The objective of this study was to analyze the radiologic features of atypical forms of squamous cell cancer and correlate them with clinical, endoscopic, and histopathologic findings. The CT and MRI images of 31 patients with atypical forms of squamous cell carcinoma were reviewed retrospectively and the radiologic findings were correlated with clinical, endoscopic, and histopathologic findings. Histopathologic diagnoses included undifferentiated carcinoma of nasopharyngeal type (n = 8), verrucous carcinoma (n = 18), spindle cell carcinoma (n = 3), and basaloid cell carcinoma (n = 2). Undifferentiated carcinoma of nasopharyngeal type was located in the supraglottis or piriform sinus beneath an intact mucosa and initial endoscopic biopsy was most often negative. The discrepancy between an intact mucosa at endoscopy and a solid mass with homogenous enhancement at CT or MRI was characteristic for these tumors and warranted further investigations to obtain the definitive histologic diagnosis. Verrucous carcinoma displayed characteristic clinical, radiologic, and pathologic features, namely, an exophytic tumor arising from the glottic level displaying a rugged surface with finger-like projections but with only minor submucosal infiltration. Spindle cell carcinoma appeared as a polypoid mass with a thin stalk arising from the supraglottis. Basaloid cell carcinoma displayed a distinct lobulated enhancement pattern which was observed on contrast-enhanced T1-weighted SE images. Although the MR and CT features of atypical forms of squamous cell carcinoma cannot be considered pathognomonic they should raise the differential diagnosis even if endoscopic biopsy has been negative. The radiologist's awareness of the appearance of these unusual tumors on CT and MR images may greatly facilitate the diagnostic work-up and helps to guide the endoscopist to the adequate biopsy site in order to establish the correct diagnosis. Received 30 April 1998; Revision received 3 June 1998; Accepted 5 June 1998