Multiple MR Imaging Techniques in the Diagnosis and Assessment of Resectability in Pancreatic Carcinoma

Objective: To study the value of multiple MR imaging techniques in the diagnosis of pancreatic carcinoma and the assessment of resectbility of the lesion. Methods: MR imaging was performed in 18 pa-tients with surgically and/or pathologically proven pancreatic carcinoma. GRE T1WI, TSE T2WI, GRE T1WI with fat suppression, delayed enhancement GRE T1WI, MRCP and 3D DCE MRA were used in MR scanning. Tumor involvement of the celiac trunk and its main branches, superior mesenteric artery,the portal, splenic and superior mesenteric veins were prospectively graded on a 0-4 scale based on cir-cumferential contiguity of tumor to vessel. Results: On GRE T1WI and TSE T2WI all the lesions showed slightly hypointense and hyperintense, respectively; On GRE T1WI with fat suppression, all the tumors obviously appeared hypointense; On delayed enhancement GRE T1WI, the lesions displayed irregularly circular enhancement in 14 patients and well-distributed enhancement in 4 patients. MRCP showed exten-sive bile and main pancreatic duct dilatation with typical “double-duct“ sign in 8 patients. On 3D DCE MRA, we thought it was unresectable with more than half circumferential involvement of tumor to vessel,so that the portal, splenic and superior mesenteric veins were involved with 56% (10/18), 39% (7/18)and 67% (12/18), respectively. The celiac trunk and its main branches and superior mesenteric arteries were involved with 22% (4/18) and 17% (3/18), respectively. The pancreatic lesions in 2 cases could be completely resected in the evaluation of MR imaging, which was fitted to the findings of operation by pan-creatoduodenectomy. The pancreatic lesions in other 2 cases were partly, resected because there was tumor extension to superior mesenteric vein and/or artery. The tumors in the remaining 14 patients were too large and involved peripancreatic vessels or there were stomach or liver metastases, so these patients were only treated by choledochojejunostomy and gastrojejunstomy. Conclusion: The “all-in-one“ MR approach including fast scanning sequences, fat suppression, MRCP and 3D DCE MRA provides the surgeon with diagnosis and assessment of resectability of tlm lesion prior to surgery of pancreatic carcinoma.     

Value of contrast-enhanced ultrasound in diagnosis ot focal liver lesions

Objective： By observing the pattern of the focal liver lesions （FLL） in different phases by real time contrast-enhanced ultrasound （CEUS）, compared to enhanced CT, investigate the value of CEUS in diagnosing focal liver lesions. Meth. ods： 35 patients with unconfirmed focal liver lesions were studied by contrast agent SonoVue and Technos DU 8 produced by Esaote company. Results： Among the 14 cases of hepatocellular carcinoma （HCC）, 10 were typical, presented with early artery enhancement and immediate wash-out. The enhancement patterns of 6 livers metastasis were diverse, including peripheral or entire degree enhancement. The wash-out time in malignant tumors was eadier than other focal liver lesions （P 〈 0.05）, appeared as hypoechoic in the portal phase or parenchyma phase. The 6 cases of hemangioma were enhanced centripetally nodular in artery phase and washed out after several minutes. The patterns of different lesions were similar compared to contrast-enhanced CT, without significant statistic differences. Conclusion： The contrast enhanced ultrasound technique can significantly improved the value of diagnosing focal liver lesions.     

颞叶放射性脑病磁共振成像的特征分析

Objective： To observe the magnetic resonance imaging （MRI） morphological features of radiation encephalopathy （REP） in nasopharyngeal carcinoma （NPC） and investigate their diagnostic value. Methods： The MRI data of 160 lesions from 104 NPC patients with the diagnosis of temporal lobe REP were retrospectively analyzed. The MRI was performed after radiation therapy of NPC with an interval ranged from 8 months to 13 years. The imaging sequences included T1-weighted imaging and T2-weighted imaging. Additionally T1-weighted imaging with injection of the contrast agent of Gd-DTPA was performed in 111 lesions and fluid attenuated inversion recovery （FLAIR） was performed on 37 lesions, and among them, 2 cases were subjected to MR perfusion weighted imaging （PWI）. Results： Unilateral temporal lobe was involved in 48 cases of REP, bilateral temporal lobe in 56 cases of REP respectively, with a total of 160 lesions. The REP in the white matter displayed hyper-intensity signal on T2-weighted imaging which could be homogenous, whereas areas with heterogeneous hypo-intensity signal could be seen in 59 of them otherwise with hyper-intensity signal, and 91 lesions of white matter were associated with gray matter lesions with an appearance of hypo-intensity signal on T1-weighted imaging and hyper-intensity signal on T2-weighted imaging. In 111 lesions with the Gd-DTPA enhanced T1-weigthed imaging, 91 showed the enhancement of brain parenchyma. Hemorrhage and hemosiderosis occurred in 5 lesions of REP. Conclusion： REP in NPC has a multiplicity of the imaging features on MRI, in addition to the common involvement of white matter, including other relatively frequent findings, such as the involvement of gray matter, hemorrhage, hemosiderosis and blood-brain barrier destruction, those could be clearly revealed on MRI.     

Diagnosis value of diffusion-weighted MR imaging with dynamic enhanced scanning toward pancreatic endocrine tumors简

Objective： The aim of our study was to analysis the pictures of conventional magnetic resonance imaging （MR）, diffusion-weighted imaging （DWl） and dynamic enhanced magnetic resonance imaging （DEMRI） of pancreatic endocrine tumors （PETs）, and evaluate diagnostic value of MR, DWl and DEMRI for diagnosing PETs. Methods： DWl and DEMRI scanning toward 13 patients with PETs being confirmed by surgical pathology before surgery on the basis of conventional MR scanning were carried out, and MR findings was analyzed retrospectively. Results： Of 13 patients with PETs there was 11 cases with single lesion, 2 with multiple, and had 15 lesions altogether, of which there were 3 lesions in pancreatic head, 1 in its neck, 2 in its body, 4 in its body and tail, 5 in its tail. MR findings： （1） T1WI signal was low or slightly lower （9/15）, and equal ones （5/15）; （2） T2WI showed high or slightly higher signal （10/15）, and equal ones （5/15）; （3） T1WI with fat suppression： the signal was low （11/15）, mixed signal （2/15）, and equal ones （2/15）; （4） DWI： normal pancreatic tissue exhibited homogeneous intermediate signal, all 15 lesions were high or slightly higher signal, the measured ADC values of tissue of PETs was （1.124 ± 0.252） × 104 mm2/s, and the ADC value of normal pancreatic tissue （1.873 ± 0.157） × 10^3 mm2/s; （5） Enhanced （M3D/LAVA） scanning： among 13 patients with PETs there were 12 pancreatic lesions with significantly enhanced signals in the arterial phase in all 15, and significantly higher than normal pancreatic tissue, and two slight enhancement was slightly higher signal; and 1 no enhancement. Enhanced pattern： homogeneous enhancement were 6 lesions, and the heterogeneous 4, and the edge ring 5. Conclusion： MR and DWl combining with DEMRI help qualitative diagnosis of pancreatic endocrine tumors.     

Magnetic Resonance Evaluation of Transplanted Endometrial Carcinoma and Its Lymph Node Metastasis in Rabbits

Objective： To establish a rabbit model of transplanted endometrial carcinoma with lymph node metastasis and observe its magnetic resonance imaging （MRI） features. Methods： VX2 tumor grafts were orthotopically embedded in the endometrium of rabbits, and 3 weeks after the transplantation, thetumor and its metastasis to the retroperitoneal lymph nodes were examined by MRI, and the signal intensities and size of the lymph nodes were compared with those of normal rabbits. Results： The orthotopic transplantation of the tumor grafts resulted in tumor growth in all the 12 recipient rabbits. The tumors infiltrated the serosa of the uterus and metastasized to the retroperitoneal lymph nodes 3 w after transplantation. MRI demonstrated that the lymph nodes of the tumor-bearing rabbits were larger in size than those of normal control rabbits, but the signal intensity of the lymph nodes was not significantly different between them. Conclusion： This transplanted endometrial carcinoma model is characterized by high success rate and similar tumor metastasis behaviors with human endometrial carcinoma, therefore may serve as a good model for testing the efficacy of contrast agents for MR lymphography.     

A Case of Epithelioid Hemangioendothelioma in the Liver

A 15-year-old girl was admitted to our hospital with a 9-month history of upper abdominal pain and loss of appetite. Her history showed no indication of hepatitis. Her abdomen appeared to be even and soft, and the liver and spleen could not be felt below the costal margin. Percussion pain in hepatic region was negative. Gastroscopy showed no abnormalities. An abdominal ultrasound examination revealed the presence of hepatic hypoechoic areas and an abdominal CT scan showed multiple roundlike low-density masses in both hepatic lobes. The edges of the focal lesions were smooth and continuous, with a heterogeneous center, the round-like edges were enhanced, but the enhancement in the focal lesions was not obvious.[第一段]     

Pilomyxoid astrocytoma in cerebellum

Pilomyxoid astrocytoma is a new identified variant type of pilocytic astrocytoma,and typically locates in the hypothalamic and chiasmatic region.Herein,we reported a nine-year-old boy with pilomyxoid astrocytoma in the cerebellum.MRI scanning showed a tumor involved the cerebellar vermis,tonsil,the forth ventricle and brainstem.It was homogeneous isointensity on T1WI,relative hyper-intensity on T2WI,hyper-intensity on fluid attenuated inversion recovery (FLAIR) images,and uniform enhancement on contrast T1WI.The tumor was sub-totally removed and was proved histologically to be pilomyxoid astrocytoma.Follow-up at the 5th month,MRI showed the residual tumor enlarged at the brainstem.The patient survived 10 months after the operation,and finally died of respiration failure resulting from brainstem dysfunction.     

Imaging analysis of primary malignant intracranial lymphoma

OBJECTIVE To investigate the images characteristics of primary malignant intracranial lymphoma. METHODS Retrospective study was conducted on CT/MRI imaging characteristics of 9 cases with primary malignant intracranial lymphoma. RESULTS The patients had lesions mostly in the supratentorial region, including the parts of deep white matter, para-ependymal regions, and corpus callosum. The shapes of the lesions were round or irregular. CT scan showed equal or slightly high density of the tumor images, compared with the normal tissue in the brain. The TIWI of MRI scan on the tumor showed low signal and the T2WI showed equal or slightly high signal. The MRI signals were homogenous. Cystic lesion, calcification, and hemorrhage were rarely seen in MRI. Edema around tumor and its occupational effect was lessened. Edema around tumor shown in MRI was not in accordance with the true volume of the tumor mass. Enhanced scan on the lesions showed homogenous enhancement, and the pia mater invaded and/or the spread along ependyma. CONCLUSION Images of primary malignant intracranial lymphoma have specific characteristics that are useful in its diagnosis and differential diagnosis.     

Establishment of orthotopic transplantation model of human bladder cancer and detection by MRI

Objective： To establish an orthotopic bladder cancer model bearing human bladder cancer for experimental research, and monitor tumor progression by magnetic resonance imaging （MRI）. Methods： The mucosa was mechanically damaged transurethrally under direct vision, and then human bladder cancer cell line T24 was inoculated into the bladders of BALB/c nude mice to establish orthotopic bladder cancer model. To find a suitable concentration of Gd-DTPA for this research. MRI was performed weekly to assess tumor growth, using Gd-DTPA as contrast agent. The pathologic morphology of the bladders and other specimens were observed with HE stain. Results： All the 25 mice developed bladder cancer after inoculation. The best concentration of Gd-DTPA was 1.408 mg/mL. On MRI, no change in the bladders was observed on day 7 after inoculation, filling defect in the bladders, accordant to actual tumor size, was detected on days 14, 21 and 28. Pathologic examination showed that tumor grew in the mucosa or superficial muscle of bladder on day 7, confined in muscle layer on days 14-28, and invaded serosa on day 35. Conclusion： Transurethrally damaged bladder mucosa under direct vision and instilled bladder cancer cell T24, we successfully established an orthotopic bladder cancer model. Tumor growth simulated the progression of human bladder cancer approximately. MRI was a reliable way for dynamic detection of murine orthotopic bladder tumor.     

Role of contrast enhanced ultrasound in radiofrequency ablation of metastatic liver carcinoma

Objective:To investigate the application of contrast enhanced ultrasound(CEUS) in planning and guiding for radiofrequency ablation(RFA) for metastatic liver carcinoma(MLC).Methods:One hundred and thirty-five patients with clinically and pathologically diagnosed MLC(from gastrointestinal tumors) were included in the present study,and 104 of them had received CEUS prior to RFA to assess the number,size,shape,infiltration,location and enhancing features of the lesions.Among the 104 patients,21(20.1%) were excluded from RFA treatment due to too many lesions or large infiltrative range based on CEUS.The remaining 83 patients with 147 lesions underwent RFA(group A).During the same period,other 31 patients with 102 lesions serving as control group were treated based on findings of conventional ultrasound without contrast(group B).The patients underwent follow-up enhanced CT at the 1st month,and then every 3-6 months after RFA.The tumor was considered as early necrosis if no contrast enhancement was detected in the treated area on the CT scan at the 1st month.Results:In group A,72 of 147 MLC lesions(48.9%) showed increased sizes on CEUS.Among them,48 lesions(66.6%) appeared enlarged in arterial phase,and 24(33.3%) showed enlarged hypoechoic area in parenchymal phase.CEUS showed total 61 additional lesions in 35 patients(42.1%)(ranged from 8 to 15 mm) compared with conventional ultrasound(US),and 42(68.8%) of them were visualized in parenchymal phase only.There were total 208 lesions in group A underwent RFA with CEUS planning,and the tumor necrosis rate was 94.2%(196/208).In this group,local recurrence was found in 16 lesions(7.7%) during 3-42 months’ following up,and new metastases were seen in 30 cases(36.1%).For group B,the tumor necrosis rate was 86.3%(88/102),local recurrence in 17 lesions(16.7%),and new metastases in 13 cases(41.9%).Tumor early necrosis and recurrence rates were significantly different between the two groups(P=0.018,P=0.016,respectively).Conclusion: CEUS played an important role in RFA for liver metastases by candidate selecting and therapy planning, which helped to improve the outcome of the treatment.     

The efficacy of MRI with ultrasmall superparamagnetic iron oxide particles (USPIO) in head and neck cancers

BACKGROUND: The objective was to evaluate the diagnostic accuracy of ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) compared to plain MRI in patients with a clinical N+ neck using histology as a gold standard. MATERIALS AND METHODS: Twenty-eight patients underwent unenhanced and USPIO-enhanced MRI using T1-weighted spin echo (SE) sequences and high resolution Turbo-Spin-Echo (TSE) T2-weighted sequences, as well as T2-weighted Gradient Echo (GE) sequences in axial and sagittal slice orientation. The signal intensity (SI) decrease was measured by a region of interest evaluation and visual analysis was performed. RESULTS: Histopathological evaluation of 363 lymph nodes revealed 34 as metastatic. USPIO MRI detected 28 metastases (sensitivity 82.3%) and 329 non-metastatic lymph nodes (specificity 100%). Regarding lymph node size, USPIO MRI was correct in all patients who underwent surgery. One lymph node with microinfiltration of tumor cells was detected by USPIO MRI. CONCLUSION: There were no side-effects during or after application of the contrast agent. This study confirms the efficacy of MRI with USPIO in patients with head and neck cancer. USPIO-enhanced MRI could have an important effect on surgery planning. Because of its high specificity, USPIO-enhanced MRI seems to be a diagnostic modality able to differentiate borderline-sized lymph nodes.     

超小超顺磁性氧化铁颗粒增强磁共振成像与钆喷替酸葡甲胺增强磁共振成像诊断兔颈转移性淋巴结的对比研究

目的 比较超小超顺磁性氧化铁颗粒(USPIO)增强磁共振成像(MRI)与钆喷替酸葡甲胺(Gd-DPTA)增强MRI两种方法诊断兔颈部反应性增生、肿瘤转移性淋巴结的能力.方法 健康成年新西兰大白兔36只,随机平均分为两组,18只制成颈部淋巴结反应性增生模型,18只制成颈部淋巴结肿瘤转移模型.两组模型各取9只行Gd-DTPA增强MRI,9只行USPIO增强MRI.Gd-DTPA增强前行T1WI、T2WI序列扫描,注射Gd-DPTA后80 s行T1WI扫描.USPIO增强前和注射USPIO后24 h,分别行T1WI、T2WI、T2*WI序列扫描.分析增强前后淋巴结信号及形态特点,与大体标本及病理结果进行对照分析.结果 肿瘤组内,Gd-DTPA增强MRI诊断转移性淋巴结的敏感度、特异度、阳性预测值、阴性预测值及准确性分别为62.5%、91.3%、88.2%、70.0%及76.6%,而USPIO增强MRI为95.0%、90.9%、90.5%、95.2%及92.9%,两种方法间敏感度和准确性差异有统计学意义(均P＜0.05).增生组内,Gd-DTPA增强MRI和USPIO增强MRI诊断良性淋巴结的准确性分别为74.2%和87.1%.结论 USPIO增强MRI诊断肿瘤转移性淋巴结的准确性高于Gd-DTPA增强MRI.     

Evaluation of brain tumor vessels specific contrast agents for glioblastoma imaging

A mouse model of glioblastoma multiforme was used to determine the accumulation of a targeted contrast agent in tumor vessels. The contrast agent, consisting of superparamagnetic iron oxide coated with dextran, was functionalized with an anti-insulin-like-growth-factor binding protein 7 (anti-IGFBP7) single domain antibody. The near infrared marker, Cy5.5, was also attached for an in vivo fluorescence study. A 9.4T magnetic resonance imaging (MRI) system was used for in vivo studies on days 10 and 11 following tumor inoculation. T(2) relaxation time was used to measure the accumulation of the contrast agent in the tumor. Changes in tumor to brain contrast because of active targeting were compared with a nontargeted contrast agent. Effective targeting was confirmed with near infrared measurements and fluorescent microscopic analysis. The results showed that there was a statistically significant (P < .01) difference in normalized T(2) between healthy brain and tumor tissue 10 min, 1 h, and 2 h point postinjection of the anti-IGFBP7 single domain antibody targeted and nontargeted iron oxide nanoparticles. A statistical difference remained in animals treated with targeted nanoparticles 24 h postinjection only. The MRI, near infrared imaging, and fluorescent microscopy studies showed corresponding spatial and temporal changes. We concluded that the developed anti-IGFBP7-iron oxide single domain antibody-targeted MRI contrast agent selectively binds to abnormal vessels within a glioblastoma. T(2)-weighted MRI and near infrared imaging are able to detect the targeting effects in brain tumors.     

Value of MR imaging in the staging of rectal carcinoma]

Correlative studies of MRI and pathologic specimens were done in 35 patients with rectal cancer. The MR manifestations of the primary tumor and its invasion into the surrounding structures were investigated with reference to the staging of rectal cancer. Prone positioning and the procedure of hypotonic air-distension of rectum was the method of choice to depict the primary tumor and tumor invasion. The spin-echo (SE)pulse sequence with TR/TE: 500/32 ms (T1-weighted image) was selected to show the anatomical structures in the pelvis and tumor spread in the surrounding fatty space and lymph node metastasis. Owing to the reduced contrast between tumor invasion and fatty tissue and decreasing signal intensity on multi-echo T2-weighted images the long repetiting time (TR) pulse sequence could not provide significant contribution in tumor staging. The MR appearance of rectal carcinoma was categorized as polypoidnodular, cauliflowermassive and protuberant-ring types. Ulceration was often seen in the latter two types. Peripheral invasion often manifested as spotty-nodular, sawtoothed-wavy and tumefied shape with medium signal intensity on T1-weighted images. The presence of a lump of small nodes, round or oval nodules within 2 cm from the rectal wall or nodular mass in the perirectal fatty space could be considered as possible lymph node metastasis. Following the modified Dukes Staging System of rectal cancer proposed by Astler-Coller all patients were staged preoperatively and correlated with surgical specimens. The accuracy of staging was 74.3%, compatible with the results of studies published.     

Magnetic resonance imaging of musculoskeletal lesions: Comparison of three fat-saturation pulse sequences

Fat-saturation (FS) pulse sequences can improve the detection of musculoskeletal lesions. We prospectively compared contrast-enhanced T1-weighted FS spin-echo (SE) images, T2-weighted FS fast spin-echo (FSE) images and inversion recovery (IR) FSE images to determine if any of these three pulse sequences is superior for depicting bone marrow and soft tissue lesions. T1-weighted FS-SE images (400-680/10-20 [TR/TE]) after intravenous injection of gadoliniumdiethylenetriaminepentaacetic acid (DTPA), T2-weighted FS-FSE (2400-4200/96-112) and IR-FSE (3700-6000/12-14/170 [TR/TE/TI]) images were obtained with a 1.5-T magnet system in 35 patients. The visibility, margination and extent of 37 bone marrow and 67 soft tissue lesions, image uniformity, susceptibility and motion artefacts were qualitatively analysed by four radiologists. The number and size of lesions detected, the mean lesion signal-to-noise ratio (S/N) and contrast-to-noise ratio (C/N) were also statistically compared. More bone and soft-tissue lesions were detected on the IR-FSE and T2-weighted FS-FSE than the T1-weighted FS-SE images. The IR-FSE images were significantly better than the T2-weighted FS-FSE and T1-weighted FS-SE images for bone marrow lesion conspicuity (P<0.01). The soft-tissue lesions were also more conspicuous on the IR-FSE and T2-weighted FS-FSE images than on the T1-weighted FS-SE images (P<0.005). The lesion extent and image quality were similar on all three sequences while motion artefacts were most severe on the IR-FSE and least severe on the T1-weighted FS-SE images (P<0.001). Fat saturation was maximal on the IR-FSE images, resulting in a significantly higher mean ON of bone marrow lesions. The mean C/N of soft-tissue lesions was higher on the T2-weighted FS-FSE images although the differences were not significant. The T2-weighted FS-FSE and IR-FSE sequences are superior to the contrast-enhanced T1-weighted FS-SE sequence for depicting musculoskeletal lesions. Bone marrow lesion conspicuity is greater on the IR-FSE images, with comparable scan time and image quality but more motion artifacts.     

2D和3D MRI结合技术在胰腺癌诊断中的应用

目的探讨多种MRI成像技术和改良增强扫描方案在胰腺癌诊断中的价值。方法对49例胰腺癌患者进行MRI检查,平扫序列分别为T1WI 2D快速小角度单次激发(FLASH)、T1WI 3D屏气容积内插法(VIBE)脂肪抑制、快速自旋回波(TSE)T2WI和T2WI半傅立叶转换单次激发快速自旋回波(HASTE)脂肪抑制MR胰胆管成像(MRCP);增强扫描方法为3D FLASH冠状位与T1WI 3D VIBE横断位交替扫描方式,即动脉期和门静脉期采用冠状位扫描,胰腺期和延迟期采用横断位扫描;最后采用T1WI 2D FLASH完成整个上腹部扫描。冠状位原始图像经最大信号强度投影(MIP)分别获得胰腺周围主要动脉和门静脉影像,用多平面重建技术获得胰腺及周围组织动脉期和门静脉期图像。结果(1)在3D VIBE平扫中,45例肿瘤为低信号,4例为等信号;在2D FLASH序列中,46例肿瘤为低信号,3例为等信号;脂肪抑制TSE T2WI 3例肿瘤为等信号,其余46例均为等和略高信号,并与周围胰腺实质均无明显分界。(2)胰腺期增强扫描,除1例肿瘤为等信号外,其余均呈相对低信号,39例肿瘤周围呈环形强化,其中24例肿瘤门静脉期及延迟期可见边缘结节样和内部分隔样强化。6例延迟强化呈等和略高信号。动脉期肿瘤均未见明显强化。(3)37例手术探查的患者,MRI 磁共振血管成像(MRA)误诊7条血管,包括3例肠系膜上动脉和4例肠系膜上静脉,其余血管均判断正确。结论应用2D和3D MRI结合技术1次检查即可同时了解胰腺肿瘤、胰胆管和血管等多系统的情况,对胰腺癌的术前诊断和手术切除性判断有重要价值。     

菲立磁增强MRI对肝脏局灶性病变的诊断价值

目的:探讨菲立磁增强MRI检查在肝脏局灶性病变诊断中的应用价值.方法:对34例临床怀疑有肝脏占位性病变,行常规MR或CT检查诊断困难的患者行菲立磁增强MR检查.用定量的方法研究增强前后T1WI及T2WI图像上病灶信号强度的变化,采用配对t检验分析其变化的显著性.结果:增强后肝脏实质T2WI信号明显降低,良、恶性病变的信号变化不同.病变的检出量增加,显示更清楚.结论:菲立磁增强MR检查可明显提高肝脏局灶性病变的检出率及鉴别诊断的准确性.     

在体和离体胰头癌的磁共振成像表现与病理对照

目的 分析在体和离体胰头癌磁共振成像(MRI)的信号特征,研究其与大体标本及组织病理特征的相关性.方法 16例胰头癌患者行MRI检查(包括2D FLASH T1WI平扫、动态增强和抑脂TSE T2WI序列扫描),行Whipple手术切除肿瘤.新鲜手术标本再行MRI检查,扫描结束后,即将肿瘤标本按MRI检查方向完整切开,制成连续切片,分析MRI表现与大体切片和组织病理的对应关系.结果 肿瘤大小1.5 cm×2.0 cm～4.8 cm×4.2 cm,平均3.6 cm×3.1 cm.在体MRI检查:T1WI序列上,14例肿瘤呈低信号,2例呈等信号;抑脂TSE T2WI序列上,3例肿瘤呈等信号,13例肿瘤呈混杂信号;胰腺实质期增强扫描,15例强化不明显呈低信号,其中11例肿瘤周围呈环形强化;肝脏期增强扫描,9例呈不规则中等强化;增强延迟期,4例延迟强化呈等或略高信号.离体MRI检查: T1WI序列上,16例肿瘤均为低信号;在抑脂TSE T2WI序列中,均为混杂信号.MRI表现和病理的相关性:各类肿瘤成分在T1WI序列上均可为低信号,等信号区以肿瘤组织及炎性细胞为主;T2WI序列上,等低信号以纤维成分为主,略高信号以肿瘤组织和慢性炎症为主,高信号为黏液变性和受压扩张的胰腺导管.增强胰腺期环形强化是多种病理成分共同作用的结果,无明显强化区为肿瘤组织及纤维组织.肝脏期和延迟期强化以纤维成分为主.结论 胰头癌肿瘤内由多种病理成分按不同比例混合而成,MRI可揭示胰头癌的病理特征.在可切除的胰头癌肿瘤内,未见明显出血坏死的病理改变.     

Magnetic resonance imaging of tumor angiogenesis using dual-targeting RGD10–NGR9 ultrasmall superparamagnetic iron oxide nanoparticles

Objective

Using RGD10–NGR9 dual-targeting superparamagnetic iron oxide nanoparticles to evaluate their potential value in tumor angiogenesis magnetic resonance imaging (MRI) and the biodistribution in vitro and in vivo.

Materials and methods

Dual-targeting RGD10–NGR9 ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles were designed and synthesized in our previous study. In vitro, prussian blue staining and phenanthroline colorimetry were conducted to evaluate binding affinity and adsorption of dual-targeting USPIO nanoparticles to αvβ3-integrin/APN positive cells. In vivo, a xenograft mouse tumor model was used to evaluate the potential of the dual-targeting nanoparticles as an MRI contrast agent. After intravenous injection, the contrast-to-noise ratio (CNR) values of MR images obtained were calculated at predetermined time-points. The iron level was detected to access the biodistribution and plasma half-time.

Results

In vitro, dual-targeting USPIO nanoparticles bound to proliferating human umbilical vein endothelia cells with high specificity. In vivo, contrast MRI of xenograft mice using dual-targeting nanoparticles demonstrated a significant decrease in signal intensity and a greater increase in CNR than standard MRI and facilitated the imaging of tumor angiogenesis in T2*WI. In terms of biodistribution, dual-targeting USPIO nanoparticles increased to 1.83 times in tumor lesions as compared to the control. And the plasma half-time was about 6.2 h.

Conclusion

A novel RGD10–NGR9 dual-targeting USPIO has a great potential value as a contrast agent for the identification of tumor angiogenesis on MRI, according to the high specific affinity in vitro and in vivo.

     

鼻咽癌放疗后放射性脑干和脊髓损伤的磁共振表现

背景与目的:鼻咽癌(nasopharyngealcarcinoma,NPC)放射治疗后脑干和颈髓放射性损伤的诊断相当重要。磁共振(magneticresonanceimaging,MRI)用于诊断鼻咽癌放疗后放射性脑损伤已有较多报道,但脑干和颈髓放射性损伤的MRI表现文献报道较少。本研究旨在分析鼻咽癌放疗后脑干和颈髓放射性损伤的MRI特征。方法:对60例鼻咽癌患者在放射治疗后6个月至5年内进行了MRI检查,MRI检查序列包括T1-weightedimage(T1WI)、T2-weightedimage(T2WI)、fluidattenuatedinversionrecovery(FLAIR);所有患者均做了MRI增强扫描。结果:6例为颈髓放射性损伤;54例为脑干放射性损伤,其中脑桥20例,桥脑基底部与延髓上段26例,中脑受累3例,延髓5例。病灶在MRI上T1WI表现为等信号和低信号,T2WI上为高信号,增强后病灶无强化者11例(18.3%),强化者49例(81.7%)。强化者有2种强化形式:均匀斑片状强化(21例,42.9%)和不均匀的既有环形又有斑片状的强化(28例,57.1%)。结论:MRI可以清晰地显示脑干和脊髓放射性损伤的病灶,结合病史可以确诊。