Breast lesions: evaluation with dynamic contrast-enhanced T1-weighted MR imaging and with T2*-weighted first-pass perfusion MR imaging

PURPOSE: To evaluate the diagnostic value of an imaging protocol that combines dynamic contrast-enhanced T1-weighted magnetic resonance (MR) imaging and T2*-weighted first-pass perfusion imaging in patients with breast tumors and to determine if T2*-weighted imaging can provide additional diagnostic information to that obtained with T1-weighted imaging. MATERIALS AND METHODS: One hundred thirty patients with breast tumors underwent MR imaging with dynamic contrast-enhanced T1-weighted imaging of the entire breast, which was followed immediately with single-section, T2*-weighted imaging of the tumor. RESULTS: With T2*-weighted perfusion imaging, 57 of 72 carcinomas but only four of 58 benign lesions had a signal intensity loss of 20% or more during the first pass, for a sensitivity of 79% and a specificity of 93%. With dynamic contrast-enhanced T1-weighted imaging, 64 carcinomas and 19 benign lesions showed a signal intensity increase of 90% or more in the first image obtained after the administration of contrast material, for a sensitivity of 89% and a specificity of 67%. CONCLUSION: T2*-weighted first-pass perfusion imaging can help differentiate between benign and malignant breast lesions with a high level of specificity. The combination of T1-weighted and T2*-weighted imaging is feasible in a single patient examination and may improve breast MR imaging.     

MR重T2W首次通过灌注成像鉴别乳腺良恶性肿瘤的价值初探

目的　评价在同 1次检查中T1W动态增强成像之后进行重T2 W (T 2 W )首次通过灌注成像的可行性 ,以及后者在鉴别乳腺良恶性肿瘤方面的诊断价值。方法　 2 9例乳腺病患者在T1W动态增强后进一步行病灶局部的T 2 W首次通过灌注成像 ,分别根据病灶T1W动态增强的早期强化程度和T 2 W首次通过灌注成像的早期信号丢失程度判定病灶的良恶性 ,计算其敏感度、特异度 ,以进行两方法间的比较。结果　应用T1W动态增强成像序列 ,良、恶性病变的信号强度增加率之间差异有显著性意义 (t=2 5 6 3,P =0 0 16 ) ,但两者的早期增强程度范围有很大的重叠 ;早期增强率诊断的敏感度为 94 % ,特异度仅为 2 5 %。应用T 2 W首次通过灌注成像序列 ,良、恶性病变之间的T2 信号强度丢失程度差异有非常显著性意义 (t=4 777,P <0 0 0 1) ,良、恶性病变的早期信号丢失率之间重叠很少 ;早期信号丢失率诊断的敏感度为 88% ,特异度为 75 %。结论　T 2 W首次通过灌注成像在鉴别良恶性乳腺肿瘤方面具有较高特异度 ;在同一患者中 ,T 2 W首次通过灌注成像结合T1W动态增强成像检查是可行的 ,可以提高乳腺MR成像的诊断准确性。     

Magnetic resonance characterization of tumor microvessels in experimental breast tumors using a slow clearance blood pool contrast agent (carboxymethyldextran-A2-Gd-DOTA) with histopathological correlation

Carboxymethyldextran (CMD)-A2-Gd-DOTA, a slow clearance blood pool contrast agent with a molecular weight of 52.1 kDa, designed to have intravascular residence for more than 1 h, was evaluated for its potential to characterize and differentiate the microvessels of malignant and benign breast tumors. Precontrast single-slice inversion-recovery snapshot FLASH and dynamic contrast-enhanced MRI using an axial T1-weighted three-dimensional spoiled gradient recalled sequence was performed in 30 Sprague-Dawley rats with chemically induced breast tumors. Endothelial transfer coefficient and fractional plasma volume of the breast tumors were estimated from MRI data acquired with CMD-A2-Gd-DOTA enhancement injected at a dose of 0.1 mmol Gd/kg body weight using a two-compartment bidirectional model of the tumor tissue. The correlation between MRI microvessel characteristics and histopathological tumor grade was determined using the Scarff-Bloom-Richardson method. Using CMD-A2-Gd-DOTA, no significant correlations were found between the MR-estimated endothelial transfer coefficient or plasma volumes with histological tumor grade. Analysis of CMD-A2-Gd-DOTA-enhanced MR kinetic data failed to demonstrate feasibility for the differentiation of benign from malignant tumors or for image-based tumor grading.     

Phyllodes tumor of the breast: correlation between MR findings and histologic grade

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of phyllodes tumor of the breast and to compare these findings with the histologic grade. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The authors reviewed the MR findings in 30 female patients aged 16-73 years (mean, 40.2 years) with surgically confirmed phyllodes tumors. Analyzed MR findings included tumor shape, margin, internal enhancement, and size; signal intensity (SI) of tumor higher than that of normal breast tissue on T1-weighted images; SI of tumor lower than or equal to that of normal tissue on T2-weighted images; cyst wall appearance; kinetic curve assessment; and apparent diffusion coefficient (ADC). The MR findings and histologic grade were statistically analyzed to determine whether any correlations existed. Significant MR findings were compared with histopathologic findings. RESULTS: Nineteen benign, six intermediate (characterized by five to nine cell reproductions at 10 high-power fields, pushing or infiltrative margins, moderate stromal cellularity, and atypia and overgrowth), and five malignant phyllodes tumors were assessed. Irregular cyst wall (P = .003), tumor SI lower than or equal to normal tissue SI on T2-weighted images (P = .005), and low ADC (P = .001) correlated significantly with histologic grade. Tumor SI higher than normal tissue SI on T1-weighted images was more frequent in the malignant (in three of five tumors) and intermediate (in three of six tumors) groups than in the benign group (in two of 19 tumors); however, it was not a significant finding (P = .024). Tumor SI higher than normal tissue SI on T1-weighted images and irregular cyst wall corresponded histopathologically to hemorrhagic infarction and necrosis, respectively. Tumor SI lower than or equal to normal tissue SI on T2-weighted images and low ADC corresponded histopathologically to stromal hypercellularity. Other findings were not significant. CONCLUSION: Several MR findings can be used to help determine the histologic grade of phyllodes breast tumors.     

CT and MRI characteristics of tumours of the temporal bone and the cerebello-pontine angle

Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare. This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristics of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fat suppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spin echo sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spin echo sequences in high resolution technique with fat suppression after the intravenous application of contrast material will be performed in the coronal plane. HRCT and MRI are both used to depict the most exact tumorous borders. HRCT excellently depicts the osseous changes for example exostosis of the external auditory canal, while also with HRCT osseous changes maybe characterized into more benign or malignant types. MRI has a very high soft tissue contrast and may therefore either characterize vascular space-occupying lesions for example glomus jugulare tumours or may differentiate between more benign or malignant lesions. In conclusion HRCT and MRI of the temporal bone are excellent methods to depict and mostly characterize tumour lesions and can help to differentiate between benign and malignant lesion. These imaging methods shall be used complementary and may have a great impact for the therapeutic planning.     

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.     

Gadolinium-enhanced echo-planar T2-weighted MRI of tumors in the extracranial head and neck: feasibility study and preliminary results using a distributed-parameter tracer kinetic analysis

PURPOSE: To examine the feasibility of first-pass dynamic contrast-enhanced (DCE) T2-weighted MRI of tumors in the extracranial head and neck by applying a distributed-parameter (DP) tracer kinetic model to quantify the perfusion parameters. MATERIALS AND METHODS: A total of 16 patients with primary malignant and benign tumors in the head and neck underwent DCE-MR studies. A spin-echo (SE) echo-planar-imaging (EPI) MR-sequence was applied for first-pass DCE-T2-weighted imaging. The data were postprocessed applying a DP tracer kinetic model that accounts for capillary-tissue exchange. Region-of-interest (ROI) analysis was performed in the tumor sites and the adjacent normal tissue. Blood flow (F), intravascular blood volume (v(1)), extravascular extracellular volume (v(2)), difference in bolus arrival time between arterial input and tissue (t(0)), intravascular mean transit time (t(1)), permeability (PS), and extraction ratio (E) maps were generated for each patient. RESULTS: All perfusion values in the tumor sites were significantly different (0.000 < or = P < or = 0.01) than those in the normal muscle tissue. The median perfusion values in the tumor tissue were: F = 150.5 mL/minute/100 g, v(1) = 11.0 mL/100 g, v(2) = 31.5 mL/100 g, t(0) = 4.5 seconds, t(1) = 8.0 seconds, PS = 96.0 mL/minute/100 g, and E = 32.5. CONCLUSION: EPI-T2-weighted DCE-MR in head and neck tumors as well as quantification of the perfusion values using DP model physiologic imaging was feasible and the promising initial results have encourages further validation studies in the future.     

Quantification of breast tumor microvascular permeability with feruglose-enhanced MR imaging: initial phase II multicenter trial

PURPOSE: To investigate use of the macromolecular contrast agent feruglose for differentiating and grading of human benign and malignant breast tumors on the basis of their microvascular characteristics. MATERIALS AND METHODS: Sixty-three women with 63 primary breast lesions were examined with dynamic T1-weighted gradient-echo magnetic resonance (MR) imaging after intravenous injection of feruglose. A two-compartment unidirectional kinetic model applied to the dynamic data yielded estimates of the endothelial transfer coefficient, KPS, and the fractional plasma volume of the tumors. These MR imaging-derived parameters were correlated with the histologic tumor grade and quantified according to the Scarff-Bloom-Richardson (SBR) score by means of Pearson product moment correlation analyses. Differences between malignant and nonmalignant breast lesions with respect to KPS for feruglose were evaluated by means of the chi2 test and by calculating the sensitivity, specificity, and positive and negative predictive values. RESULTS: Histologic analysis revealed 26 benign and 37 malignant tumors. A moderate yet statistically significant correlation between KPS and SBR score was found (R = 0.496, P <.001). No significant correlation was observed between fractional plasma volume and SBR score (R = 0.085, P =.507). The KPS values were zero for 19 (73%) of the 26 benign tumors and were greater than zero for 27 (73%) of the 37 carcinomas. This distribution was significantly different (chi2 = 13.035, P =.001). With the criterion KPS > 0 in carcinomas, sensitivity was 0.73, specificity was 0.73, and the positive predictive value was 0.79. CONCLUSION: Quantitative measures of tumor microvascular permeability can be used for breast tumor characterization. The probability of breast tumor microvascular hyperpermeability to be associated with malignancy is 79%.     

Magnetic resonance imaging of soft-tissue tumors of the extremities: A practical approach

Diagnosis of extremity soft-tissue tumors can be challenging. Characteristics of tumor margins can help precisely identify locally aggressive or non-aggressive behavior for surgical planning, but cannot differentiate benign from malignant lesions. Most malignant tumors can have inhomogeneous signals on T2-weighted images. Although a uniform signal on T2-weighted images can be a reliable indication of a benign lesion, a well-defined mass with homogeneous internal signal intensity does not definitively identify a benign lesion. Some common and distinctive soft-tissue lesions can have specific clinical and imaging features allowing a diagnosis without biopsy. These are known as determinate lesions. This illustrative report presents a diagnostic guide for extremity soft-tissue tumors based on tissue signal and morphological characteristics on magnetic resonance images. It is important for clinicians to be familiar with the imaging characteristics of common determinate lesions.     

Usefulness of diffusion-weighted MRI in differentiating benign from malignant musculoskeletal tumors

PURPOSE: To evaluate the usefulness of diffusion-weighted MRI in distinguishing different components and in differentiating benign from malignant musculoskeletal tumors. MATERIALS AND METHODS: Fifty-seven patients with musculoskeletal tumors underwent MR at our institution from October 1999 to April 2002. We evaluated 57 tumors (9 bone tumors and 48 soft tissue tumors). All tumors were classified into 8 groups (myxomatous, fibrous, cystic, cartilaginous, fatty components, hematomas, other benign tumors, and other malignant tumors). MR examinations were performed with a 1.5-Tesla system. Diffusion-weighted single-shot EPI images were obtained in all patients. Apparent diffusion coefficients (ADCs) were calculated by using b factors of 0 and 1,000 sec/mm2. RESULTS: ADC values of myxomatous, cystic, and cartilaginous components were significantly higher than those of other tumors. In cartilaginous tumors, malignant tumor ADC values (2.33 +/- 0.44) were higher than those of benign tumors (2.13 +/- 0.13). However, there was no significant difference between benign and malignant tumors. Except for high-intensity components on T1-weighted imaging and low or homogeneously very high intensity components on T2-weighted imaging, there was a significant difference in ADC between malignant (1.35 +/- 0.40) and benign (1.97 +/- 0.50) tumors. CONCLUSION: Within the limited number of cases, there was a significant difference in ADC between malignant and benign tumors.     

乳腺肿瘤MRI序列联合运用与微血管密度的对照研究

目的：探讨同一次检查中T2WI首次通过灌注成像及T1WI动态增强成像的联合应用在鉴别乳腺良恶性肿瘤方面的价值,并对所有病灶进行免疫组化CD34染色计数微血管密度进行评分,评价其相关性。方法：37例乳腺患者经手术或穿刺病理证实分为良恶性两组,经过MRIT2WI首次通过灌注成像后进一步行T1WI动态增强成像,对灌注及动态增强各参数进行分析,并与手术后病理图像及免疫组化结果对照。结果：乳腺肿块37例,乳腺癌21例,乳腺良性病灶16例,应用T2WI首过灌注成像,良恶性组早期信号强度丢失率之间重叠很少,敏感性为90%,特异性为75%;较T1WI动态增强组（敏感性47.6%,特异性为68.7%）提高;恶性组最大信号强度下降率与微血管密度MVD有明显正相关性（r=0.502,P〈0.05）,最大信号强度下降时间与微血管密度无明显相关性。良性组最大信号强度下降率、最大信号强度下降时间与微血管密度均无明显相关性。结论：乳腺癌T2WI灌注成像表现与病理特征相符,在乳腺癌血管生成的评价方面有重要价值。联合T2WI首次通过灌注成像及T1WI动态增强成像能够提高乳腺肿瘤的诊断特异性。     

Magnetic resonance imaging of the prostate

The prostate was examined by magnetic resonance imaging (MRI) in 33 subjects, including five normal volunteers, 18 with prostatic carcinomas, seven with benign nodular hyperplasias, two cases of acute prostatitis, and one case of chronic prostatitis. Of 18 prostatic carcinomas, 16 produced an inhomogeneous signal intensity, with areas of diminished signal on T1-weighted scans and usually increased signal on T2-weighted images relative to the rest of the prostate. However, a similar appearance was also seen in five cases of benign nodular hyperplasia. It is doubtful at present whether MRI is able to reliably differentiate benign from malignant prostatic disease. Extraprostatic tumor extension and pelvic adenopathy was well shown, and MRI is very promising as a method for the preoperative staging of known prostatic carcinomas.     

MR imaging characterization of microvessels in experimental breast tumors by using a particulate contrast agent with histopathologic correlation

PURPOSE: To define the diagnostic potential of magnetic resonance (MR) imaging enhanced with ultrasmall superparamagnetic iron oxide (USPIO) particles for the quantitative characterization of tumor microvasculature. MATERIALS AND METHODS: NC100150 injection, a USPIO in clinical trials, and albumin-(Gd-DTPA)(30) were compared at MR imaging on sequential days in the same 19 rats with mammary tumors. Kinetic analysis of dynamic T1-weighted three-dimensional spoiled gradient-recalled imaging data with a two-compartment bidirectional model yielded MR imaging estimates of microvascular permeability (K(PS)) and fractional plasma volume (fPV) for each contrast medium. RESULTS: Strongly positive and significant correlations were observed between MR imaging-derived K(PS )estimates and histologic tumor grade with either the soluble albumin-(Gd-DTPA)(30) (r = 0.88; P <.001) or larger particulate USPIO (r = 0.82; P <.001). A significant correlation (P <.05) was observed with each contrast medium between K(PS) and the histologic microvascular density (MVD), an angiogenesis indicator. Despite the considerable difference in molecule and particle sizes, no significant difference was observed in the MR imaging-derived mean permeability values generated with the two contrast media. CONCLUSION: USPIO, a macromolecular particulate MR imaging contrast agent, can be applied successfully to characterize tumor microvessels in animals. USPIO-derived K(PS) correlated strongly with histopathologic tumor grade, MVD, and K(PS) values derived by using albumin-(Gd-DTPA)(30) in the same tumors.     

Epithelial tumors of the ovary: comparison of MR and CT findings

Forty patients with 50 ovarian epithelial tumors of the ovary were retrospectively studied. They underwent computed tomography and magnetic resonance (MR) imaging within 1 week of surgery. MR examinations were performed with a superconducting magnet (0.5 T) and predominantly T1- and T2-weighted MR imaging. T1-weighted MR images were obtained in eight patients after contrast material was administered. Signal intensity of tumors was compared with that of urine, muscle, and fat. Morphologic features that were evaluated included size, vegetations, septations, wall thickness, fluid or solid components, and vascularity. On the basis of signal intensity and morphologic characteristics, MR imaging helped in the correct diagnosis of benign serous cystadenoma in 10 of 13 tumors, benign mucinous cystadenoma in seven of 10 tumors, and tumors of low malignant potential and malignant tumors in 23 of 27 tumors. Accuracy for overall characterization of benign versus malignant tumors was 86% with MR imaging and 92% with computed tomography. There was no difference in sensitivity (P = 1) or specificity (P = .5).     

Nerve sheath tumors: evaluation with CT and MR imaging.

Tumors of nerves are classified into benign (schwannoma and neurofibroma) and malignant nerve sheath tumors. Schwannomas almost always occur as solitary lesions, whereas neurofibromas may occur alone or in a greater number, especially in patients with the peripheral form of von Recklinghausen's disease. Benign nerve sheath tumors often present as asymptomatic, slowly growing soft tissue masses. Although malignant nerve sheath tumors are relatively rare, a sudden increase in the size of a lesion, in particular in a patient with neurofibromatosis, should raise the suspicion of malignant change. On computed tomography (CT) and magnetic resonance imaging (MR) a benign nerve sheath tumor usually appears as a well-defined, oval, spherical or fusiform mass with smooth borders and distinct outlines, located in the subcutaneous tissue or centered at the expected anatomic location of a nerve, with displacement of adjacent soft tissues. Generally nerve sheath tumors have a low density on unenhanced CT scans. On MR they are isointense to muscle on T1-weighted images, whereas on T2-weighted images the signal intensity is high. Both on CT and MR the degree of contrast enhancement is moderate to marked and may be homogeneous or inhomogeneous. MR has become the method of choice for evaluating the anatomic location, contour, and relation of a nerve sheath tumor to adjacent neural, vascular, and muscular structures. The imaging criteria for malignant nerve sheath tumors are not specific enough to distinguish them from other malignant soft tissue tumors, so that neither CT nor MR can establish a definite diagnosis.     

Incidentally found and unexpected tumors discovered by MRI examination for temporomandibular joint arthrosis

We examined the frequency of incidentally found or unexpected tumors discovered at the time of magnetic resonance imaging (MRI) examinations in the temporomandibular joint (TMJ) region for patients with suspicion of TMJ arthrosis. Five MR images (T1-weighted transverse scout image and proton density and T2-weighted oblique sagittal images at the open and closed mouth) were acquired. In 2776 MRI examinations of TMJ arthrosis, two tumors were discovered. They consisted of an adenoid cystic carcinoma in the deep portion of the parotid gland, and a malignant tumor extending from the infratemporal fossa to the parapharyngeal space. The rate of incidentally founded or unexpected tumors in TMJ examinations was low (0.072%), but the two tumors found were malignant tumors, and therefore, scout image should be carefully examined, not only used for positing the slice.     

Improved detection and delineation of head and neck lesions with fat suppression spin-echo MR imaging.

To compare conventional and fat suppression MR imaging in their ability to detect head and neck lesions, we prospectively studied 17 patients with head and neck tumors and one normal volunteer. Five patients had benign tumors (one mixed cell tumor, one hemangioma, one lipoma, and two plexiform neurofibromas), 10 had malignant tumors (six squamous cell carcinomas, two minor salivary gland carcinomas, one lymphoma, and one malignant fibrous histiocytoma), and two had nonspecific lymphadenopathy. All subjects were studied with standard spin-echo T1- and T2-weighted images (T2-weighted imaging was done with and without fat suppression technique). In addition, T1-weighted images with contrast enhancement and fat suppression were obtained in nine patients. A four-point grading system was used for comparison of the conventional and fat suppression images. Grades ranged from 0 (unsatisfactory, the lesion cannot be seen) to 3 (excellent, the lesion and its margins can be seen clearly with sharp contrast from surrounding normal tissue). We found that postcontrast fat suppression T1-weighted images and fat suppression T2-weighted images were most useful; these sequences obtained an average score close to grade 3 (2.77 and 2.85, respectively). On the other hand, the conventional T2-weighted images had an average score of about 2 (1.82) and the conventional T1-weighted image had a score of about 1 (1.33). Fat suppression T2-weighted sequences generally were superior in cases of lymphadenopathies. Postcontrast T1-weighted images were most useful in a case of plexiform neurofibroma, owing to their fibrous component and lower proton density.(ABSTRACT TRUNCATED AT 250 WORDS)     

MR imaging of gastrointestinal leiomyosarcoma

Two cases of leiomyosarcoma, one in the esophagus and the other in the small intestine, underwent magnetic resonance imaging (MRI). Spin echo T1-weighted images of both leiomyosarcomas showed almost the same intensity as muscle. Spin echo T2-weighted images showed the tumors to be hyperintense compared with fat; however, the esophageal tumor was more hyperintense than the small intestinal one. The jejunal leiomyosarcoma had a central cavity on MRI and CT, suggesting that it was malignant.     

MRI and pathological findings in two cases of askin tumors

Summary Askin tumors are primitive peripheral neuroectodermal tumors (PPNET) located in the thoracopulmonary region. This entity was first proposed in 1979 by Askin et al. These highly malignant tumors occur primarily in children and young adults. Pre- und postoperative MRI findings are presented for two pathologically proven cases. MRI is the most appropriate imaging modality for the diagnosis and eventual follow-up for these tumors. They appear homogenous, and iso- or discretely hypointense in comparison to the spinal cord on T1-weighted images and hyperintense on proton density and T2-weighted images. They show a very stark contrast enhancement after i. v. injection of paramagnetic contrast agents. Sharp tissue borders, and exact tumor extension were shown in both cases. The high signal intensity on T2-weighted images was not altered by chemotherapy.