Advanced MRI applications and findings of malignant phyllodes tumour: review of two cases

Phyllodes tumour or cystosarcoma phyllodes is a rare stromal breast tumour that is usually benign but on rare occasions can turn malignant. Non-specificity of the imaging features on sonography and mammography makes it difficult to distinguish malignant from benign counterparts solely based on imaging. The final diagnosis is still highly dependent on histopathological assessment. Herein, we describe two cases of malignant phyllodes tumour with emphasis on magnetic resonance (MR) imaging features using advanced MR applications.     

Nondiffuse fatty change of the liver: discerning pseudotumor on MR images enhanced with ferumoxides-initial observations

PURPOSE: To clarify the findings of nondiffuse fatty change of the liver on ferumoxides-enhanced magnetic resonance (MR) images. MATERIALS AND METHODS: Of 202 patients who underwent ferumoxides-enhanced MR imaging, eight who had nondiffuse fatty change of the liver at computed tomography (CT) were examined as study subjects. MR imaging findings before and 1 hour after ferumoxides administration were compared with CT findings. RESULTS: Focal fatty areas of the liver showing low attenuation on CT images were depicted as areas of relatively high intensity on the ferumoxides-enhanced T1-weighted images in all patients. On enhanced T2-weighted images, focal fatty change showed relatively high intensity in three and isointensity in one of the four patients. Focal spared areas appearing as areas of relatively high attenuation on CT images were depicted as areas of relatively low intensity on the ferumoxides-enhanced T1- and T2-weighted images in all patients. CONCLUSION: Although prior reports of hepatic MR imaging with ferumoxides indicated that there is accumulation of ferumoxides within focal fatty areas that are no longer seen after the administration of contrast medium, this study revealed that focal fatty change and focal spared areas of fatty liver may be pseudotumors because of the relatively high intensity of fatty areas of the liver. Radiologists can distinguish these conditions from hepatic tumors by using the opposed-phase gradient-echo sequence or the fat-saturation technique.     

Cerebral aspergillosis: MR imaging and histopathologic correlation.

The authors report a case of intracranial aspergillosis secondary to immunosuppression. Signal intensity changes in the lesion on brain MR are compared with gross and histopathologic findings at autopsy. A peripheral ring of low signal intensity relates to a dense population of Aspergillus hyphal elements and small areas of hemorrhage. CT findings are included for comparison.     

MR appearance of cartilage defects of the knee: preliminary results of a spiral CT arthrography-guided analysis

The aim of this study was to determine signal intensity patterns of cartilage defects at MR imaging. The MR imaging (3-mm-thick fat-suppressed intermediate-weighted fast spin-echo images) was obtained in 31 knees (21 male and 10 female patients; mean age 45.5 years) blindly selected from a series of 252 consecutive knees investigated by dual-detector spiral CT arthrography. Two radiologists determined in consensus the MR signal intensity of the cartilage areas where cartilage defects had been demonstrated on the corresponding reformatted CT arthrographic images. There were 83 cartilage defects at spiral CT arthrography. In 52 (63%) lesion areas, the MR signal intensity was higher than that of adjacent normal cartilage with signal intensity equivalent to (n=31) or lower than (n=21) that of articular fluid. The MR signal intensity was equivalent to that of adjacent normal cartilage in 17 (20%) lesion areas and lower than that of adjacent cartilage in 8 (10%) lesion areas. In 6 (7%) lesion areas, mixed low and high signal intensity was observed. The MR signal intensity of cartilage defects demonstrated on spiral CT arthrographic images varies from low to high on fat-suppressed intermediate-weighted fast spin-echo MR images obtained with our equipment and MR parameters.     

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.     

Delineation of gliomas with magnetic resonance imaging using Gd-DTPA in comparison with computed tomography and positron emission tomography

Fourteen patients with cerebral gliomas were investigated by MR imaging using Gd-DTPA (Magnevist), CT with the contrast agent iohexol (Omnipaque) and, as a reference, positron emission tomography (PET) using 11C-L-methionine. Tumour areas with disruption of the blood-brain-barrier (BBB) as seen on MR and CT were compared with areas increased accumulation of methionine in PET. There were 6 patients with high-grade astrocytoma (grade III-IV), 5 with low-grade astrocytoma (grade I-II) and 3 with oligodendroglioma. In 4 high-grade tumours, PET showed a larger tumour or tumour tissue in additional areas, compared with enhancement on MR and CT, while in 2 cases the tumour extension was similar in the three modalities. In the low grade tumour group, the findings on PET differed from those on post-contrast MR or CT in 7 cases. In 3 of these cases, no disruption of the BBB was seen either on MR or on CT. In 2 of our 14 patients CT showed larger enhancement extension than MR and in 2 cases MR was superior to CT in this respect. The enhancement intensity was higher on MR in 4 patients and on CT in 2 patients. No definite difference in the delineation of tumour tissue between the T1 weighted SE sequences was found. The gradient echo sequences FLASH and FISP gave limited information that was less than that provided by the T1 weighted SE sequences. A greater increase in signal intensity in T1 weighted images was usually seen 5 min post-contrast in the high-grade tumours than in the low-grade ones.     

Segmental intensity differences in the liver on MR images: a sign of intrahepatic portal flow stoppage

Segmental intensity differences (SIDs) in hepatic parenchyma free of tumor were noted in six patients with hepatic masses (hepatocellular carcinoma in five and metastatic liver cancer in one). Areas of SID were homogeneous in intensity. The intensity of the affected region was high in all six patients on T2-weighted magnetic resonance (MR) images and low in two on T1-weighted images. Three of five patients examined with plain computed tomography (CT) had corresponding segmental areas of low attenuation. Angiograms obtained in five patients showed occlusion of the intrahepatic portal vein, segmental staining corresponding to the region of the SID, or both. Twelve of 82 patients examined with MR imaging and angiography had similar findings on angiograms, and ten of them had abnormal intensity of anatomic distribution around or beside the liver tumors on MR images. MR imaging may be more sensitive than plain CT in the detection of secondary changes caused by intrahepatic portal flow stoppage.     

乳腺叶状肿瘤MRI表现特征分析

目的分析乳腺叶状肿瘤(phyllodes tumors,PTs)MRI平扫、动态增强、扩散加权成像(DWI)和磁共振波谱(MRS)表现特征,提高对本病MRI诊断水平。资料与方法搜集2005年1月至2008年12月期间于我院行乳腺MRI检查并经手术病理证实的5例乳腺PTs,按照美国放射学会提出的乳腺影像报告和数据系统磁共振成像(BI-RADS-MRI)标准,回顾性分析病变的MRI表现,包括形态学、平扫T1WI及T2WI信号、动态增强表现及强化曲线类型、DWI信号及表观扩散系数(ADC)值和MRS表现特征。结果5例乳腺PTs病理诊断良性1例,交界性2例,恶性2例。MRI上4例表现为分叶状,1例为卵圆形;5例PTsMRI平扫T1WI均呈较低信号,T2WI呈高信号,其中1例内有低信号分隔;4例行动态增强检查的PTs于动态增强早中期(增强后第一至第三时相)呈快速渐进性强化,动态增强中后期时间-信号强度曲线3例呈平台型,1例呈轻度流出型;5例PTs于DWI上均呈高信号,ADC值低于正常乳腺组织,且低于鉴别乳腺良恶性病变的ADC界值;3例行MRS检查,均可见胆碱(Cho)峰。结论MRI检查有助于乳腺PTs的诊断,但确诊仍需...     

Retroperitoneal neurilemoma: CT and MR findings.

OBJECTIVE. Our objective was to characterize the CT and MR imaging findings of retroperitoneal neurilemomas. MATERIALS AND METHODS. We reviewed the CT and MR imaging findings in six women with retroperitoneal neurilemomas. RESULTS. Retroperitoneal neurilemomas were round, 5-13 cm in diameter, and located in the presacral pelvic retroperitoneum in four patients and adjacent to the kidney in two patients. CT findings of the tumors were well-demarcated round masses showing prominent cystic changes and oriented in a somewhat radial fashion. Medium and heavily T2-weighted MR images showed high-intensity necrotic areas and nonnecrotic areas of various signal intensity. CONCLUSION. CT findings of a round mass with prominent cystic degeneration, along with certain MR imaging characteristics, may be helpful in the preoperative diagnosis of retroperitoneal neurilemomas.     

阔韧带平滑肌瘤的影像诊断(附九例报告)

目的 研究阔韧带平没肌瘤的影像诊断。方法 回顾性总结９例经手术和病理证实为阔韧带平滑肌瘤的Ｂ超、ＣＴ及ＭＲＩ表现。结果 ９例Ｂ超检查表现为盆腔内、子宫外实性肿块,呈低回声灶,４例内有斑点状液性暗区或不均匀光点,５例显示包膜,７例边界清晰。８例ＣＴ检查７例表现为实性肿块,边界较清晰,平扫密度较均匀,与子宫肌密度相当或稍低;１例为混合密度灶,可见液化、坏死与囊变;８例增强扫描实性部分均见明显强化,４例     

Giant cavernous hemangioma of the liver: CT and MR imaging in 10 cases

Ten giant cavernous hemangiomas of the liver in eight patients were examined with both MR imaging and dynamic bolus CT. The maximal diameters of the tumors were 6.5-19 cm (mean, 10.8 cm). MR imaging was done with a 2.0-T superconducting magnet and spin-echo imaging. CT was done with single-bolus dynamic scans. On MR images, all 10 hemangiomas had a heterogeneous appearance. The main part of the tumor comprised uniform, well-defined, high-intensity areas on T2-weighted images, with increasing intensity ratios with prolongation of TR and TE. Other parts of the tumor were cleftlike and were of lower intensity than the remainder of the tumor on T1-weighted images and of higher intensity on heavily T2-weighted images. These parts corresponded to the areas of the tumor that were of lower density on dynamic bolus CT scans. Internal septa in the tumor of low intensity were also noted on all MR pulse sequences. These parts corresponded to low-density areas on delayed contrast-enhanced CT. Familiarity with the characteristics of the internal architecture of giant cavernous hemangiomas on MR imaging or dynamic bolus CT might be useful in making the correct diagnosis of this tumor.     

Adult neuroblastoma: radiologic and clinicopathologic features

PURPOSE: The purpose of the current study was to define the imaging findings of adult neuroblastoma (ANB) and correlate them with clinicopathologic features. MATERIALS AND METHODS: The CT scans and MR images of six patients with histologically confirmed ANB (mean age, 49 years) were retrospectively analyzed. RESULTS: The arising sites of tumors included the retroperitoneum (n = 2), pelvis (n = 2), anterior mediastinum (n = 1), and adrenal gland (n = 1). The common CT finding was poorly marginated and heterogeneous mass without calcification. Cystic components were often found. On contrast-enhanced CT or MR images, tumors showed heterogeneous enhancement. On T2-weighted images, all masses demonstrated predominantly hyper signal intensity relative to skeletal muscle and the images showed heterogeneous appearance with focal areas of high intensity interspersed with septations of low signal intensity. Soft tissue masses with bone involvement were identified in one case on MR images. The CT findings in one tumor originating from mediastinum were similar to those of tumors arising from other sites. CONCLUSION: ANB is an uncommon malignancy that often pursues an aggressive clinical course, involves multiple sites, and has a poor prognosis. Tumors usually manifest on CT or MR images as a poorly demarcated mass mainly in the retroperitoneum and pelvis. Imaging studies can depict aggressive characteristics and disease extent of ANB.     

CT and MR imaging of malignant germ cell tumor of the undescended testis

Preoperative localization of the impalpable undescended testis is necessary to facilitate proper surgical planning. There is an increased incidence of malignant change in the undescended testis; demonstration of malignancy before surgery will significantly alter the treatment. We describe the computed tomographic (CT) and magnetic resonance (MR) findings in 2 patients with malignant change in an intraabdominal testis. The CT scan revealed lesions with areas of low density, 1 of which had focal calcifications; MR revealed lesions of predominantly low or intermediate signal intensity on both long and short TR/TE images, with some areas of very high signal on both sequences. After initial management with chemotherapy, the residual tumor was surgically resected. In neither instance was residual normal testis demonstrated. Both CT and MR are ideal methods of examining malignant transformation of the undescended testis, because of their ability to characterize the internal structure of the organ and, in the case of MR, its capacity for multiplanar imaging. They are almost of equal value except for the ability of CT to identify calcification and of MR to diagnose hemorrhage.     

Differentiation between postoperative scar and recurrent disk herniation: prospective comparison of MR, CT, and contrast-enhanced CT

Twenty-five symptomatic postlumbar surgery patients had findings on lumbar spinal noncontrast CT that were equivocal for distinguishing recurrent disk herniation from postoperative epidural fibrosis (scar). Contrast-enhanced CT and lumbar MR imaging were performed to differentiate these two conditions. Of the 14 levels, surgically explored, the diagnosis of scar or recurrent disk herniation was correct with contrast-enhanced CT at 10 levels and with MR imaging at 11 levels. At the levels operated on less than 2 years prior to MR imaging, scar more frequently demonstrated intermediate than low signal intensity. Scar older than 2 years most often showed low signal intensity. These preliminary findings suggest that MR may be useful in differentiating postoperative fibrosis from recurrent disk herniation in a significant proportion of patients whose unenhanced CT scans are equivocal.     

MR imaging of thymoma--comparison with CT, operative, and pathological findings]

Twenty-six patients with thymoma, who had magnetic resonance (MR) imaging and computed tomography (CT) before surgery, were studied. Twenty-six thymomas were classified into 11 non-invasive thymomas (Masaoka's clinical stage I) and 15 invasive thymomas (stage II, III, and IV). On MR imaging compared with histological findings, low signal intensity rim of the tumor was corresponded to fibrous capsule of the tumor, and linear and/or reticular low signal intensity lines in the tumor were corresponded to the fibrous septae dividing thymoma into lobules. The detectability of these findings by MR imaging was superior to that by CT. Margin of the tumor was smooth in non-invasive thymoma rather than invasive thymoma. The diagnostic accuracy of invasion to vessel, and pleura or lung on MR imaging and CT was compared with operative and histological findings. MR imaging was same as CT in its ability to detect tumoral invasion to vessel, and slightly superior to pleura or lung. In conclusion MR images clearly show the findings corresponding to pathologic specimens, and MR imaging combining with CT is useful to differentiate non-invasive thymoma to invasive thymoma.     

CT and MR imaging of malignant germ cell tumor of the undescended testis

Preoperative localization of the impalpable undescended testis is necessary to facilitate proper surgical planning. There is an increased incidence of malignant change in the undescended testis; demonstration of malignancy before surgery will significantly alter the treatment. We describe the computed tomographic (CT) and magnetic resonance (MR) findings in 2 patients with malignant change in an intraabdominal testis. The CT scan revealed lesions with areas of low density, 1 of which had focal calcifications; MR revealed lesions of predominantly low or intermediate signal intensity on both long and short TR/TE images, with some areas of very high signal on both sequences. After initial management with chemotherapy, the residual tumor was surgically resected. In neither instance was residual normal testis demonstrated. Both CT and MR are ideal methods of examining malignant transformation of the undescended testis, because of their ability to characterize the internal structure of the organ and, in the case of MR, its capacity for multiplanar imaging. They are almost of equal value except for the ability of CT to identify calcification and of MR to diagnose hemorrhage.     

腮腺基底细胞腺瘤的CT和MRI特点

目的 探讨腮腺基底细胞腺瘤的CT和MRI表现特点.方法 回顾性分析经手术病理证实的9例腮腺基底细胞腺瘤的CT和MRI的影像特点(6例CT检查,3例MR检查).9例中男4例,女5例,中位年龄58岁(40～79岁).对肿瘤的部位、大小、形态、边缘、CT密度或MRI信号及强化形式进行分析.结果 9例患者均为单发肿瘤,8例位于腮腺浅叶,1例位于腮腺深叶.9个肿瘤中7个为类圆形,无分叶;2个为长椭圆形,有浅分叶.9个肿瘤边缘均光滑清楚;MR检查3例,2个肿瘤周边见T2wI低信号的包膜,1个肿瘤周边见一较薄的T2WI高信号环.3个肿瘤MRI均表现为长T1、短T2信号,增强后呈不均匀轻、中度强化,内见裂隙样、小片状低信号,并出现延迟强化,1例见壁结节;CT检查6例,平扫肿瘤均表现为低密度,其中4个肿瘤CT强化共同特点均为薄壁环形强化,且有大小不等的壁结节,肇结节呈中～重度强化(平均CT值增加为65.5 HU),另外2个呈均匀中度强化.结论 老年女性患者腮腺浅叶内单发边界清楚病灶,CT增强表现为薄壁环形强化且有壁结节,MRI表现为长T1、短T2信号,强化内见裂隙样、小片状低信号且出现延迟强化,要考虑基底细胞腺瘤的可能.     

CT, MR, and Angiography Findings of a Solitary Fibrous Tumor of the Larynx: a Case Report

This report details the CT, MR, and angiography findings of a solitary fibrous tumor involving the larynx of a 34-year-old man. A precontrast CT scan revealed a well-defined isodense mass in the submucosal region of the supraglottic larynx. The tumor appeared as a mixed intensity lesion on the T1- and T2-weighted MR images. A T2-weighted MR image showed a central, round, and low signal intensity area within the mass. For both the CT and MR images, the mass demonstrated heterogeneous enhancement following the administration of contrast material. The angiography showed a hypervascular tumor with heterogeneous persistent staining.     

Osseous metastasis from renal cell carcinoma: "flow-void" sign at MR imaging

PURPOSE: To characterize the appearance and determine the importance of the "flow-void" sign on magnetic resonance (MR) images of patients with osseous metastasis from renal cell carcinoma. MATERIALS AND METHODS: Three musculoskeletal radiologists retrospectively and independently reviewed the medical records of 16 patients who had undergone MR imaging and in whom 20 osseous metastatic lesions from renal cell carcinoma had been diagnosed on the basis of clinical and radiologic findings. They assessed the MR images for the presence and frequency of the flow-void sign--multiple dot-like or tubular structures with low signal intensity. They then compared these findings on MR images with the corresponding areas on available images obtained with radiography (n = 16), computed tomography (CT) (n = 6), and digital subtraction angiography (n = 3) and with the results of histopathologic analysis for the same patient group. They noted the location, diameter, and appearance of the lesion and the flow-void sign, as well as variations in signal intensity within the lesion and among lesions. Statistical analysis was performed to determine the level of interobserver agreement. RESULTS: Radiographic findings and the level of signal intensity on MR images were nonspecific for diagnosis of osseous metastasis from renal cell carcinoma. The flow-void sign was identified at the lesion core or margin with a mean frequency of 76.7% by the three observers (in 15, 16, and 15 of 20 lesions, by observers 1, 2, and 3, respectively). Most of these areas of low signal intensity were tubular structures of less than 3 mm in diameter; in three lesions, they measured 5-8 mm in diameter. In 14 lesions, these structures corresponded to dilated blood vessels or veins identifiable on CT images (six lesions) or digital subtraction angiographic images (four lesions) or at histopathologic analysis (four lesions). The flow-void sign on MR images corresponded to vessels depicted on the CT scans available for six lesions and on the angiographic images available for four lesions. CONCLUSION: Observation of the flow-void sign in lesions depicted on musculoskeletal MR images may prove helpful for diagnosing osseous metastasis from renal cell carcinoma and for treatment planning, especially in patients with occult or forgotten primary renal tumor.     

MR imaging of malignant pleural mesothelioma

The magnetic resonance (MR) findings in three patients with malignant pleural mesothelioma are described. All patients had a circumferential pleural mass surrounding the lung on the affected side. These tumors had a signal of intermediate intensity on T1-weighted images. The T2-weighted images showed a slight increase in signal intensity of the mass, with focal areas of very high signal intensity due to pleural fluid. Adenopathy was demonstrated by CT and MR in two patients. The extent of the tumor and its effects on adjacent structures were well appreciated on the coronal MR images.