Masses of the hand and wrist: detection and characterization with MR imaging

To assess the value of MR imaging in the detection, delineation, and characterization of mass lesions of the hand and wrist, we reviewed the MR imaging findings of 38 patients referred for evaluation of such lesions. Twenty-five patients had a palpable mass. In an additional 13 patients an occult mass lesion was suspected as the cause of distal ulnar neuropathy. Twenty-two mass lesions (16 benign and six malignant) were detected by MR. All were correctly predicted to be benign or malignant. In nine (56%) of the 16 benign mass lesions, the specific diagnosis was suggested. In the remaining seven benign mass lesions and in the six malignant tumors, the MR findings were not specific enough to permit a diagnosis. Of the 14 patients referred for evaluation of a distal ulnar neuropathy, an occult ganglionic cyst compressing the ulnar nerve was revealed with MR imaging in three. MR imaging of the hand and wrist is accurate in the detection of mass lesions and can correctly distinguish benign from malignant tumors in the majority of cases. Specific diagnoses can be made in certain benign lesions. Occult mass lesions can be confirmed or excluded as the cause of distal ulnar neuropathy with MR imaging.     

The value of CT in rectal villous tumors

Computed tomography of 13 patients with villous rectal tumors was reviewed. Five tumors were benign, eight were malignant. All five benign lesions demonstrated homogeneous focal colonic wall thickening of less than 2 cm. Seven of the eight malignant lesions demonstrated focal colonic wall thickening greater than 2 cm. "Fronds," characterized by contrast within the interstices of the lesion, were seen in three malignant lesions. In the remaining five malignant lesions, three had a polypoid appearance, one had low attenuation regions, and one had focal rectal wall thickening. Computed tomography upstaged two carcinomas, downstaged two carcinomas, and accurately staged four carcinomas. Our experience shows (a) CT can demonstrate the classic fronds of villous tumors; (b) benign villous tumors tend to be less than 2 cm and are nonspecific in appearance; (c) biopsy is necessary to differentiate small malignant lesions from benign lesions; and (d) CT is inaccurate in staging local invasion of malignant villous tumors.     

Malignant parotid tumors: clinical use of MR imaging and histologic correlation.

Magnetic resonance (MR) imaging was performed in 116 patients in whom a parotid mass lesion was clinically suspected. Eighty-six patients had benign disease. The 30 patients in whom a malignant tumor was found were further evaluated. To determine which features are characteristic of malignant parotid tumors, spin-echo T1- and T2-weighted images of malignant lesions in the parotid gland were compared with those of benign disease. In our series, tumor margins, homogeneity, or signal intensity were not discriminative factors to correctly predict benign or malignant disease. Infiltration into deep structures (eg, the parapharyngeal space, muscles, and bone) was observed only in malignant tumors. Infiltration into subcutaneous fat was noticed in malignant as well as in inflammatory disease. No statistically significant correlation was found between tumor grade and MR imaging features in malignant disease. MR imaging is useful in delineating malignant tumors but is unreliable in correctly predicting the histologic nature of a mass lesion in the parotid gland.     

子宫内膜良、恶性息肉样病变的MR表现与临床病理对照分析

目的 探讨常规MR及动态增强扫描在子宫内膜息肉样病变中的诊断价值及病理基础.方法 回顾性分析经病理证实的子宫内膜息肉样病变48例,其中恶性肿瘤26例(23例I期子宫内膜癌和3例子宫内膜肉瘤),良性息肉样病变22例(子宫内膜息肉12例和子宫黏膜下肌瘤10例),分析其MR平扫及增强图像病灶特征,并与病理结果 进行对照.采用Fisher精确概率法对纤维核、囊变区及完整结合带在不同子宫内膜息肉样病变中的出现概率进行分析比较.结果 26例子宫内膜恶性息肉病变,其中23例子宫内膜癌在MR T2WI上均表现为子官内膜均匀等或稍高信号肿块(23/23),增强后相对于肌层均呈低信号(23/23),并伴结合带中断或模糊(20/23);子宫内膜含间质成分恶性肿瘤3例,2例为腺肉瘤,1例为癌肉瘤,MR T2WI均为混杂信号,早期局部明显强化,至后期仍明显持续强化;26例子宫内膜恶性息肉病变在MRI上子宫结合带中断或模糊征象出现的概率(23/26)均较子宫内膜息肉(1/11)及子宫黏膜下肌瘤(1/9)高,差异具有统计学意义(P值均<0.05).肿块内小囊变影及不定形纤维核影见于子宫内膜息肉(分别为8/12及5/12),2种征象在子宫内膜息肉中的出现概率均较子宫内膜恶性息肉样病变(3/26及2/26)及子宫黏膜下肌瘤(0及2/10)高,差异具有统计学意义(P值均<0.05);10例子宫黏膜下平滑肌瘤MRI均表现为境界清晰,T2WI呈等或稍低信号肿块,且出现子宫黏膜推移征象(10/10).MR平扫及增强扫描对所有48例子宫内膜息肉样病变的定性诊断敏感度为92.3%(24/26),特异度为83.3%(20/24),准确度为95.8%(46/48).结论 MRI平扫及增强扫描能反映子宫内膜良、恶性息肉样病变的特征,具有很高的诊断价值.     

Imaging features of benign mass lesions in the nasal cavity and paranasal sinuses according to the 2017 WHO classification

The World Health Organization (WHO) 2017 classification of head and neck tumors has been just published and has reorganized tumors of the nasal cavity and paranasal sinuses. In this classification, three new entities (seromucinous hamartoma, NUT carcinoma, and biphenotypic sinonasal sarcoma) were included, while the total number of tumors has been reduced by excluding tumors if they did not occur exclusively or predominantly in this region. Among these entities, benign tumors were classified as sinonasal papillomas, respiratory epithelial lesions, salivary gland tumors, benign soft tissue tumors, or other tumors. In contrast, inflammatory diseases often show tumor-like appearances. The imaging features of these benign tumors and tumor-like inflammatory diseases often resemble malignant tumors, and some benign lesions should be given attention in the follow-up period and before surgery to avoid recurrence, malignant transformation, or massive bleeding. Understanding the CT and MR imaging features of various benign mass lesions is clinically important for appropriate therapy. The purpose of this article is to describe the clinical characteristics and imaging features of each of clinically important nasal and paranasal benign mass lesions, as classified according to the WHO 2017 classification of head and neck tumors, along with some inflammatory diseases.     

Trigeminal neuropathy: Gd-DTPA enhanced MR imaging

A review of 17 patients with Gd-DTPA enhancing lesions of the trigeminal nerve (6 patients with benign tumors, 4 with inflammatory disease, 7 with malignant tumors) was conducted to determine if contrast enhanced MR imaging is superior to nonenhanced imaging and to identify imaging characteristics that aid in separating benign and malignant disease. Contrast enhanced imaging appears to be superior to nonenhanced imaging in patients with intrinsic fifth nerve lesions. Malignant lesions are suggested by enlarged, enhancing fifth nerves with irregular margins and benign lesions by minimal or no enlargement with smooth margins. Overlap of imaging findings between benign and malignant disease strongly suggests that follow-up imaging and clinical findings are of utmost importance. Gadolinium-enhanced MR imaging of the fifth nerve is recommended in patients with trigeminal sensory or motor deficits as well as those with atypical trigeminal neuralgia.     

软组织肿块的MRI诊断价值

目的：探讨软组织肿块的MRI诊断价值。方法：回顾性分析43例经手术或穿刺活检病理证实的软组织肿块患者的MRI资料。结果：MRI能清晰显示出肿块的形态学改变及其范围，尤其对邻近结构受侵情况以及与神经血管柬的关系的显示较为敏感。部分有特异性形态及信号强度征象的肿块如脂肪瘤、血管瘤等依据其MRI可以明确诊断。良恶性两组肿块在大小、信号均匀性、边界及对周围结构的侵犯等方面差异无显著性意义（P〉0．05），其MRI特征有很大重叠性。MRI对软组织肿块潜在恶性评估的敏感性、特异性分别是66．67％、60％。结论：MRI对于发现肿块及显示病变所侵及的范围是最敏感、最准确的，对软组织肿块的诊断有很大的帮助，但在鉴别肿块良恶性方面的价值存在一定局限性。     

Zystische Tumoren des Pankreas

Cystic lesions of the pancreas encompass a broad spectrum of benign, premalignant, and malignant tumors which are primarily cystic or result from cystic necroses of solid neoplasms. Because of the wide use of cross-sectional imaging techniques they are increasingly being identified in asymptomatic patients as well as in patients presenting with abdominal pain, jaundice or pancreatitis. Among these lesions, intraductal papillary mucinous neoplasms, serous cystic neoplasms and mucinous cystic neoplasms represent the majority of cases. With increasing experience with these tumors, a refinement of our understanding of their morphology and of their natural course has emerged. It is important to be familiar with the CT and MR imaging features of these lesions to differentiate these tumors and to orient the diagnosis towards benign or malignant forms. Because characterization of cystic tumors of the pancreas can sometimes be difficult due to overlapping imaging features, additional criteria such as clinical symptoms, localization, age and gender have to be taken into account. If appropriately treated, these tumors can usually be cured by resection and the decreasing risk of pancreatic surgery has led to an increasing number of resections of pancreatic tumors. The management of cystic tumors of the pancreas has not yet been standardized and the correct evaluation and subsequent management of the disease in asymptomatic patients have not been fully defined.     

Characterization of bone and soft-tissue tumors with in vivo 1H MR spectroscopy: initial results

PURPOSE: To determine if in vivo detection of choline by using hydrogen 1 (1H) magnetic resonance (MR) spectroscopy with dynamic contrast material-enhanced MR imaging can help differentiate between benign and malignant musculoskeletal tumors. MATERIALS AND METHODS: MR imaging was performed in 36 consecutive patients with bone and soft-tissue tumors larger than 1.5 cm in diameter. Examinations were performed at 1.5 T with a surface coil appropriate for the location of the lesions. Single-voxel 1H MR spectroscopy was performed by using a point-resolved spectroscopic sequence with echo times of 40, 135, and 270 msec. The volume of interest within lesions was positioned on the areas of early enhancement (<8 seconds after arterial enhancement) according to the findings of dynamic contrast-enhanced MR imaging with subtraction. The criterion for determining whether choline was present in a lesion was a clearly identifiable peak at 3.2 ppm in at least two of the three spectra acquired at echo times. MR spectroscopic results and histopathologic findings were determined in blinded fashion and compared with kappa statistics. P <.001 was considered to indicate a significant difference. RESULTS: Choline was detected in 18 of 19 patients with malignant tumors and in three of 17 patients with benign lesions. The three benign lesions included one perineurioma, one giant cell tumor, and one abscess. Choline was not detected in 14 patients with benign lesions nor in one patient with a densely ossifying low-grade parosteal osteosarcoma. In vivo 1H MR spectroscopy characterized bone and soft-tissue tumors, resulting in a sensitivity of 95%, specificity of 82%, and accuracy of 89% (P <.001). CONCLUSION: Choline can be reliably detected in large malignant bone and soft-tissue tumors by using a multiecho point-resolved spectroscopic protocol. 1H MR spectroscopy can help differentiate malignant from benign musculoskeletal tumors by revealing the presence or absence of water-soluble choline metabolites.     

Soft-tissue tumors of the foot: value of MR imaging for specific diagnosis

We reviewed MR imaging findings in 14 patients with primary soft-tissue tumors of the foot and compared them with surgical and pathologic findings to determine the value of MR imaging in anatomic localization, delineation, and characterization of such lesions. Nine tumors (64%) were benign, and five (36%) were malignant. The anatomic location (compartment, space, relation to specific tendon) and extent of all tumors were accurately shown by MR imaging. Twelve tumors (86%) were correctly characterized as benign or malignant. Eight (89%) of nine benign lesions showed distinctive MR imaging features that correctly suggested a specific diagnosis. These included hemangioma (high T2-weighted intensity and internal septa), ganglion cyst (homogeneous, high T2-weighted weighted intensity and peritendinous location), plantar fibromatosis (nodularity of plantar aponeurosis with low intensity on all sequences), and pigmented villonodular synovitis (low T2-weighted intensity and lower intensity rim). Aggressive fibromatosis (one case) could not be characterized. Four (80%) of five malignant neoplasms had MR imaging findings suggesting soft-tissue sarcoma. Two synovial sarcomas were inhomogeneous and showed extensive peritendinous growth. Two clear cell sarcomas arose at the origin of the plantar aponeurosis and infiltrated adjacent muscle. A small clear cell sarcoma could not be characterized as benign or malignant. MR imaging of the foot is accurate in showing the extent of soft-tissue tumors, which is helpful for surgical planning. Determination of their specific anatomic location may help characterize some tumors. Although our series is small, it appears that MR imaging often suggests a specific diagnosis in certain benign soft-tissue tumors of the foot and may often correctly distinguish benign from malignant tumors.     

Magnetic resonance elastography of the breast: correlation of signal intensity data with viscoelastic properties

OBJECTIVES: We sought to investigate the potential value of magnetic resonance (MR) elastography to improve the differentiation between benign and malignant tumors. MATERIAL AND METHODS: Measurements of 5 patients with 6 malignant lesions, 11 patients with benign lesions, and 4 patients with no lesions at all were performed at 1.5 Tesla. After breast MR imaging, MR elastography was performed as a targeted measurement. Low-frequency mechanical waves (65 Hz) were transmitted into the breast tissue using an oscillator and were displayed by means of a MR sequence within the phase of the MR image. After reconstruction, the viscoelastic information was correlated with the signal intensity and morphology data. RESULTS: All examinations were technically successful realized in approximately 25 minutes. Malignant tumors documented higher values of elasticity than benign corresponding with signal intensity and morphologic data. CONCLUSION: A good separation exists between benign and malignant lesions in elasticity, corresponding with specific signal intensity and morphologic data. Further clinical studies with a larger number of patients are needed for extended validation.     

Dynamic spin-echo imaging with Gd-DTPA: value in the differentiation of hepatic tumors

Thirty patients with hemangiomas (n = 6), benign liver cell tumors (n = 7), and primary or metastatic malignant tumors of the liver (n = 17) underwent dynamic MR imaging with Gd-DTPA to determine the value of the procedure in the differentiation of hepatic tumors. The diagnoses were proved by histology or follow-up. Hemangiomas had a significantly greater mean T2 value (192.1 +/- 34.8 msec) than did both benign liver cell tumors (71.9 +/- 16.9 msec; p less than .01) and primary or metastatic malignant tumors (79.7 +/- 21.2 msec; p less than .01), but the T2 values of benign liver cell tumors and malignant tumors were not significantly different. Both hemangiomas and benign liver cell tumors had a significantly greater mean signal-intensity ratio (1.86 +/- 0.60 and 1.77 +/- 0.26, respectively) than did malignant tumors (1.04 +/- 0.34; p less than .01) in the early phase after Gd-DTPA administration, and hemangiomas had a significantly greater signal-intensity ratio (1.59 +/- 0.21) than did both benign liver cell tumors (1.21 +/- 0.08; p less than .01) and malignant tumors (1.06 +/- 0.26; p less than .01) in the delayed phase. These results suggest that dynamic MR images obtained after administration of Gd-DTPA are useful in differentiating hepatic hemangiomas, benign liver cell tumors, and malignant liver lesions.     

胸膜局灶性病变动态增强MRI的研究

目的评价MR T2W I和增强检查对胸膜局灶性病变的诊断价值。方法本组31例胸膜局灶性病变均经手术或穿刺活检细胞病检或临床追踪证实。其中恶性肿瘤16例,良性病变15例。MR动态增强扫描后在工作站上比较信号强度和增强形态,并将感兴趣区(RO I)的信号强度绘制成时间-信号强度曲线(TIC),分别计算其0.5 m in斜率值。结果31例胸膜局灶性病变在T2W I平扫的表现上良恶性比较差异有统计学意义(P均<0.05)。本组TIC可分为3型,Ⅰ型17例(恶性肿瘤14例,良性病变3例);Ⅱ型4例(恶性肿瘤2例,良性病变2例);Ⅲ型10例(均为良性病变)。16例恶性肿瘤中14例病变的0.5 m in斜率值>0.00227;15例良性病变中8例病变的0.5 m in斜率值<0.00227;良恶性病变的TIC斜率值之间存在显著性差异。以0.5 m in斜率值0.00227作为鉴别胸膜局灶性良恶性的阈值,31例病变中22例诊断准确,敏感度为87.5%,特异度为53.3%。结论以病灶信号特点、形态、曲线类型或斜率值等判别胸膜病灶的良恶性,有一定的参考价值。     

Diagnostic challenges and pitfalls in MR imaging with hepatocyte-specific contrast agents

The use of gadolinium-based hepatocyte-specific contrast agents (HSCAs) has increased markedly since their introduction, and hepatocellular phase imaging performed with an HSCA is now a key part of the standard magnetic resonance (MR) imaging work-up for focal liver lesions. An understanding of the mechanisms of action of HSCAs helps ensure their effective use. The optimal delay for hepatocellular phase image acquisition differs between the two currently available HSCAs, gadoxetic acid and gadobenate dimeglumine, and MR imaging protocols must be adjusted accordingly. In addition, familiarity with typical and atypical appearances of benign and malignant focal liver lesions at HSCA-enhanced hepatocellular phase MR imaging, along with knowledge of the processes that are most likely to produce atypical appearances, is required to achieve optimal diagnostic accuracy.     

In-vivo Proton Magnetic Resonance Spectroscopy in Adnexal Lesions

Objective

To explore the in-vivo ¹H- MR spectral features of adnexal lesions and to characterize the spectral patterns of various pathologic entities.

Materials and Methods

Thirty-one patients with surgically and histopathologically confirmed adnexal lesions underwent short echo-time STEAM (stimulated echo acquisition method) ¹H- MR spectroscopy, and the results obtained were analysed.

Results

The methylene present in fatty acid chains gave rise to a lipid peak of 1.3 ppm in the ¹H- MR spectra of most malignant tumors and benign teratomas. This same peak was not observed, however, in the spectra of benign ovarian epithelial tumors: in a number of these, a peak of 5.2 ppm, due to the presence of the olefine group (-CH=CH-) was noted. The ratios of lipid peak at 1.3 ppm to water peak (lipid/water ratios) varied between disease groups, and in some benign teratomas was characteristically high.

Conclusion

An intense lipid peak at 1.3 ppm is observed in malignant ovarian tumors but not in benign epithelial tumors. ¹H- MRS may therefore be helpful in the differential diagnosis of adnexal lesions.     

MRI在涎腺肿物诊断中的作用

为了探讨不同涎腺肿物的ＭＲＩ特征，本文回顾性观察了２４例病理证实涎腺肿物的ＭＲＩ表现。结果发现良、恶性肿瘤在形态特征方面存在差异性，良性肿物多呈圆形、类圆形，可有清晰可见的包膜，肿瘤膨胀性生长，界线清楚；恶性肿瘤多浸润性生长，侵犯邻近肌肉，形态不规则，界线不清。对良性肿物的进一步组织学定性ＭＲＩ可提供一定价值的信息资料，增强扫描有助于涎腺肿瘤的定性诊断。     

False-negative MR imaging of malignant breast tumors

In this study we analyze MR-negative malignant lesions of the breast. A total of 204 patients with palpable and/or mammographic lesions were studied. The MR technique consisted of the turbo FLASH and MP-RAGE subtraction techniques. All patients underwent surgical biopsy and/or mastectomy and all specimens were examined by the correlative radiologic-histologic mapping technique. A total of 208 lesions were evaluated; 145 turned out to be malignant and 63 proved to be benign. Six malignant lesions were misinterpreted as benign on MR imaging; thus, suspicious contrast enhancement was present in 96 % of the lesions detected by mammography, US, or clinical examination. Especially 4 of the 17 ductal carcinoma in situ (DCIS) lesions were misinterpreted (23.5 %). Despite optimal technique, 6 malignant lesions were not identified by MR imaging. The highest prevalence of these MR occult lesions was in the group of DCIS. Although MR imaging has an important role in the evaluation of breast lesions and, primarily, in ruling out malignancy, one should be aware of the fact that false-negative MR findings do occur. Received 8 July 1996; Revision received 7 October 1996; Accepted 6 February 1997     

Malignant nerve-sheath neoplasms in neurofibromatosis: distinction from benign tumors by using imaging techniques

Malignant peripheral nerve-sheath neoplasms frequently complicate neurofibromatosis causing pain, enlarging masses, or neurologic deficits. However, similar findings sometimes also occur with benign nerve neoplasms. Our study was done retrospectively to determine if imaging techniques can differentiate malignant from benign nerve tumors in neurofibromatosis. Eight patients with symptomatic neoplasms (three benign, five malignant) were studied by CT in eight, MR in six, and 67Ga-citrate scintigraphy in seven. Uptake of 67Ga occurred in all five malignant lesions but not in two benign neoplasms studied. On CT or MR, all eight lesions, including three benign neoplasms, showed inhomogeneities. Of five lesions with irregular, infiltrative margins on CT or MR, four were malignant and one was benign. Of three lesions with smooth margins, one was malignant and two were benign. One malignant neoplasm caused irregular bone destruction. Accordingly, CT and MR could not generally distinguish malignant from benign lesions with certainty. However, both CT and MR provided structural delineation to help surgical planning for both types of lesion. 67Ga scintigraphy appears promising as a screening technique to identify lesions with malignant degeneration in patients with neurofibromatosis. Any area of abnormal radiogallium uptake suggests malignancy warranting further evaluation by CT or MR. Biopsy of any questionable lesion is essential.     

Intramedullary Disease of the Spine: Diagnosis Using Gadolinium-DTPA-Enhanced MR Imaging

Twenty-six patients with suspected lesions of the spinal cord were studied before and after administration of gadolinium-DTPA to assess whether contrast enhancement was useful in the MR evaluation of intramedullary disease. Nine patients had primary tumors, six had benign syringes, three had multiple sclerosis with cord involvement, three had thrombosed vascular malformations, three had probable intramedullary metastasis, and two were normal. Although all lesions were detected on noncontrast MR scans, gadolinium-DTPA was of great help in their delineation and characterization. Specifically, contrast material may be able (1) to localize tumor nidus and separate it from edema, in cases of hemangioblastomas and metastases; (2) to suggest regions of more active tumors, in cases of glioma, for surgical biopsy or removal; (3) to differentiate benign or reactive processes from neoplastic lesions, such as reactive cyst from tumor cyst or hematoma due to thrombosed malformation from tumor hemorrhage; and (4) possibly to differentiate active from inactive lesions, for example, in multiple sclerosis.Because of these advantages, gadolinium-DTPA probably will often be used routinely when intramedullary lesions are detected on noncontrast MR scans.     

Benign and malignant tumor of the uterine body with broccoli sign: MR imaging features for differential diagnosis

The characteristic morphology called broccoli sign combines a stalk and prolapsed tumor and is a useful diagnostic indicator of prolapsed tumor of the uterine body. Magnetic resonance (MR) imaging findings of broccoli sign are common for uterine submucosal leiomyomata but not well described for other tumors of the endometrial cavity, such as endometrial polyp, atypical polypoid adenomyoma, endometrial carcinoma, carcinosarcoma, and adenosarcoma. Both benign and malignant masses of the uterine body can show broccoli sign. The MR imaging features of prolapsed uterine tumor with broccoli sign resemble those of usual uterine body tumors, but the location is different. We describe the MR imaging features of prolapsed uterine tumors with broccoli sign.