Diffusion-weighted MR imaging in gynecologic cancers

Diffusion-weighted imaging (DWI) reflects changes in proton mobility caused by pathological alterations of tissue cellularity, cellular membrane integrity, extracellular space perfusion, and fluid viscosity. Functional imaging is becoming increasingly important in the evaluation of cancer patients because of the limitations of morphologic imaging. DWI is being applied to the detection and characterization of tumors and the evaluation of treatment response in patients with cancer. The advantages of DWI include its cost-effectiveness and brevity of execution, its complete noninvasiveness, its lack of ionizing radiation, and the fact that it does not require injection of contrast material, thus enabling its use in patients with renal dysfunction. In this article, we describe the clinical application of DWI to gynecological disorders and its diagnostic efficacy therein.     

Correlation of diffusion-weighted MR imaging with cellularity of renal tumours

BACKGROUND: Diffusion is a physical process based on the random movement of water molecules known as Brownian movement. Diffusion-weighted imaging (DWI) is a magnetic resonance (MR) technique that provides information about the biophysical properties of tissues such cell organization and density, microstructure and microcirculation. MATERIALS AND METHODS: Twenty healthy volunteers and 18 patients with renal tumor were enrolled in our study. The DWI was obtained before contrast media injection with a single-shot SE EPI Inversion Recovery (IR) sequence. The tumor cellularity of each resected lesion was evaluated. RESULTS: The mean apparent diffusion coefficient (ADC) value of renal tumors was significantly lower than the mean ADC value of normal renal parenchyma. In our series, the mean ADC value of renal tumors did not significantly correlate with tumor cellularity, but correlated with histological architecture. CONCLUSION: These preliminary results indicate the utility of DWI in the acquisition of tissue characterization data of renal masses using a minimal acquisition time (17 sec).     

Diffusion-weighted magnetic resonance imaging of intracranial epidermoid tumours

Intracranial epidermoids can closely mimic cerebrospinal fluid (CSF) on MRI and CT. Therefore epidermoids can be difficult to detect, or distinguish from CSF. Three cases of intracranial epidermoid are presented, one of which closely mimicked an arachnoid cyst on CT and routine MRI sequences. Diffusion-weighted magnetic resonance imaging (DWI) was performed. All three epidermoids demonstrated marked restriction of diffusion relative to CSF, clearly defining the extent of each lesion, and allowing differentiation from an arachnoid cyst or an enlarged CSF space.     

Diffusion-weighted MR imaging abnormalities in pediatric patients with surgically-treated intracranial mass lesions

SummaryIntroduction Diffusion-weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique that measures the degree of water diffusion in vivo. DWI abnormalities are frequently observed on immediate postoperative imaging following surgical resection of gliomas in adults. These abnormalities subsequently demonstrate contrast enhancement, which may be confused with lesion recurrence. The purpose of this study was to investigate the occurrence of these postoperative abnormalities in pediatric patients with intracranial mass lesions.Methods Thirty-three consecutive patients ≤18 years old with a newly diagnosed intracranial mass lesion underwent MRI, including DWI, before and immediately after surgical treatment.Results The median patient age was 9.9 years (range 0.2–18 years). Supratentorial and infratentorial lesions were identified in 22 and 11 patients, respectively. Infiltrative and noninfiltrative, as well as benign and malignant lesions, were included. Postoperative imaging demonstrated areas of reduced diffusion adjacent to the resection cavity in 20 (61%) cases. The median volume of these areas was 1.7 cm³ (range 0.3 cm³–12.0 cm³). Subsequent imaging studies in 9 of the 18 cases showed contrast enhancement in the area corresponding to the DWI abnormality. There were no clinical deficits attributable to any of the diffusion abnormalities. There was no association between the occurrence of these abnormalities and whether the lesion was infiltrative, non-infiltrative, benign, or malignant.Conclusions DWI abnormality on immediate postoperative MRI is common following surgery for newly diagnosed intracranial mass lesions in pediatric patients. Focal contrast enhancement in the postoperative period may be confused with recurrence for some lesions. Our study suggests that immediate postoperative DWI is useful in interpreting new areas of focal contrast enhancement on subsequent imaging in children who have had surgery for brain tumors.     

The role of imaging in renal and extra-renal rhabdoid tumours

Rhabdoid tumour of the kidney is an uncommon malignancy with a poor prognosis that usually occurs in childhood. Certain imaging features may help distinguish this lesion from the much more common Wilmstumour ‘. Extra-renal rhabdoid tumours appear to have no specific imaging characteristics.     

不同病理亚型肾细胞癌的磁共振成像表现

目的 探讨不同病理亚型肾细胞癌(RCC)的磁共振成像(MRI)表现.方法 回顾性分析术前行MRI检查、术后经病理证实的79例患者的81个RCC病灶的影像学表现,比较不同病理亚型RCC在MRI平扫和增强扫描不同时期肿瘤的强化程度与方式、肿瘤侵犯程度以及与手术和病理结果 的对照.绘制MRI增强扫描不同时期区分透明细胞癌与非透明细胞癌的操作者特征性曲线,确定用于两者区分的肿瘤实质标准信号噪声比(SNR)值的最佳临界点,进行诊断效价检验.评价不同病理亚型RCC的肾外侵犯程度.结果 81个RCC病灶中,透明细胞癌58个,嫌色细胞癌10个,乳头状细胞癌8个,未分类癌5个.T1WI和T2WI序列平扫时,嫌色细胞癌的均质度较高,信号均匀;透明细胞癌的信号不均匀,多为混杂信号.增强扫描时,透明细胞癌主要表现为不均匀强化,嫌色细胞癌主要表现为均匀强化.在增强扫描的皮髓交界期、肾实质期和排泄期,区分透明细胞癌与非透明细胞癌的最佳临界标准SNR值为616、579.和278.综合比较,增强扫描肾实质期更利于区分透明细胞癌与非透明细胞癌,其敏感度、特异度、阳性预测值、阴性预测值和准确度分别为62.1%、91.3%、94.7%、48.8%和70.3%.RCC的病理分型与肾外侵犯情况无关.结论 不同病理亚型RCC的MRI表现存在差异;MRI检查可以为临床选择个体化的治疗方案及预测疗效提供一定的帮助.     

CT and MR imaging in the evaluation and staging of lung cancer

Cancer of the lung is one of the most frustrating yet important challenges facing medicine today. Despite screening programs and education of the public concerning the established link of lung cancer and cigarette smoking, the overall incidence of lung cancer continues to rise. Improved imaging has led to more accurate staging. Expanded treatment has yielded improving survivals of certain specific tumors. Accurate diagnosis and staging of lung cancer is important in detecting therapy and prognosis. Computed tomography (CT) has been established as an important component of the staging process. More recently, applications of magnetic resonance imaging (MRI) are ideally suited to evaluate tumor extent and nodal disease. We reviewed the uses and limitation of CT and MRI. Compared with CT, the relatively low signal in the lung limits the detection of pulmonary nodules and other lung parenchymal diseases, and noise due to motion has been a frequent and significant problem in thoracic MRI. Because of its superior spatial resolution and ability to detect calcification, CT is better than MRI for the detection and evaluation of lung nodules and mediastinal adenopathy when assessing lung cancer. For the detection of mediastinal invasion or lymph node metastases, CT and MRI generally provide similar information. However, volume averaging problems, which may occur on trasaxial CT, can be avoided or clarified using MRI, and nodes can sometimes be more clearly distinguished from vessels using this technique. In the diagnosis of hilar masses or lymphadenopathy, CT and MR provide similar information in the majority of cases, but occasionally MR may more clearly indicate the presence or absence of a mass. Because of superb vascular imaging capability (without the need for exogenous contrast agents), exquisite soft tissue contrast, the ability to image the chest directly in multiple planes, and the potential to characterize certain tissues, MRI appears to be superior to CT in defining the extent of chest-wall invasion. In general, CT is superior to MRI as an all-around tool for imaging the wide range of thoracic abnormalities that can be present in patients with lung cancer. Limited availability, and longer examination time of MRI compared with CT has restricted the use of thoracic MRI. If MRI is used selectively as a secondary imaging study to answer specific questions raised or unanswered by CT, its value can be optimized.     

磁共振弥散加权成像在胶质瘤分级中的价值

目的 探讨磁共振弥散加权成像(DWI)及表观弥散系数(ADC)在鉴别胶质瘤瘤体区、瘤周区和正常组织中的应用及鉴别胶质瘤良、恶性的价值.方法 采用Philips 1.5T Achieva超导型磁共振成像仪,对46例胶质瘤患者行常规MRI及DWI,弥散系数b值分别取0和1 000 s/mm2,测量瘤体区、瘤周区及对侧正常组...     

动态增强MR成像在孤立型肺结节中的应用

Objective:The aim of our study was to investigate the value of dynamic contrast-enhanced MRI for evaluating differential diagnosis of pulmonary isolated lesions.Methods:Twenty-nine consecutive patients enrolled in this study,all of whom underwent DCE-MRI examinations and received a histologic and clinical diagnosis.Among these,lung tuberculoma 7 cases,harmatoma 3 cases,peripheral lung cancer 19 cases.DCE-MRI was acquired with 3D LAVA technique,total 18 phases were acquired,scanner time of per phase was 5-7".After contrasting agent,twice successive scanning was acquired at 10" and 50".Then 1'30",2',2'30",3',3'30",4',5',6',7',8',9',10',11',12' performed scanning.Region of interest was placed on the Maximum level in the tumors.According to Schaefer's standard,four types of time signal intensity curve(TIC)were classified,which were A,B,C and D.Compared the dynamic parameters between benign and malignant nodules.Results:Lung tuberculoma may display three curves:A type 1 case,ring-shaped enhancement 4 cases(periphery ring A type,central region D type),D type 2 cases.Harmatoma may display three curves:A type 1 case,C type 2 case.Peripheral lung cancer may display A type.Except 2 cases D type lung tuberculoma,we compared curve data of 8 cases benign nodules(including tuberculoma A type and periphery ring A type,harmatoma A type and C type)and lung cancer.SIEP%:benign nodules 0.7885+0.5543,lung cancer 1.2623+0.3059,P＜0.05;MER:benign nodules 1.0007+0.4251,lung cancer 1.3694+0.2740,P＜0.05;washout:P>0.05.Conclusion:Lung MR imaging is helpful to diagnosis and differential diagnosis of isolated benign and malignant nodules.SIEP% and MER could offer valuable information.The evolution of global tuberculosis may be from A type to ring-shaped ennoblement to D type.It was easy to do right diagnosis to lung tuberculoma with ring-shaped ennoblement and D type.Peripheral lung cancer commonly displayed A type and needed identification with acute inflammation.So,it is important to anti-inflammatory follow-up for a few A type nodules.     

A simple, reproducible method for monitoring the treatment of tumours using dynamic contrast-enhanced MR imaging

Dynamic contrast-enhanced MR imaging (DCE-MRI) may act as a biomarker for successful cancer therapy. Simple, reproducible techniques may widen this application. This paper demonstrates a single slice imaging technique. The image acquisition is performed in less than 500 ms making it relatively insensitive to respiratory motion. Data from phantom studies and a reproducibility study in solid human tumours are presented. The reproducibility study showed a coefficient of variation (CoV) of 19.1% for K(trans) and 15.8% for the initial area under the contrast enhancement curve (IAUC). This was improved to 16 and 13.9% if tumours of diameter less than 3 cm were excluded. The individual repeatability (the range within which individual measurements are expected to fall) was 30.6% for K(trans) and 26.5% for IAUC for tumours greater than 3 cm diameter. This approach to DCE-MRI image acquisition can be performed with standard clinical scanners, and data analysis is straightforward. For treatment trials with 10 patients in a cohort, the CoV implies that the method would be sensitive to a treatment effect of greater than 18%. The individual repeatability is well inside the 40% change shown to be important in clinical studies using this DCE-MRI technique.     

Genetics of renal tumours

The two main renal tumours, Wilms' tumour and renal cell carcinoma, are associated with distinct molecular genetic abnormalities. The genes involved behave as Knudson oncosuppressor genes. Further dissection of the molecular biology pathways involving WT1 and VHL genes is providing fascinating insight into the biology of these genes, the development and cell biology of the kidney and its tumours.     

肝外胆管癌常规磁共振和磁共振胆胰管造影的诊断价值

目的 探讨肝外胆管癌的常规磁共振(MRI)和磁共振胆胰管造影(MRCP)影像表现和临床应用价值。方法 54例经手术病理证实的肝外胆管癌经常规MRI检查,其中MRCP44例,Gd-DTPA增强扫描29例。综合分析MR1和MRCP的影像学表现和诊断,并与手术病理结果进行对照。结果 MRI显示肿块39例,29例增强扫描中22例病灶强化,胆管壁不规则增厚13例。MRCP显示病变部位胆管中断,梗阻近端形态截断状或圆锥状16例,鸟嘴状或鼠尾状26例,杯口状2例。29例显示梗阻远端的胆管。结合常规MRI和MRCP原始与重建图像,定位诊断准确率为96．3％,定性诊断准确率为92．6％。结论 常规MRI和MRCP源像是MRCP诊断肝外胆管癌的重要补充。MRCP结合常规MRI对肝外胆管癌定位诊断准确,定性诊断有较高特异性。     

Current status of body MR imaging: fast MR imaging and diffusion-weighted imaging

The recent technical advances in fast MR imaging have greatly enhanced the clinical value of MR imaging of the body. Advances in T₁-weighted images have enabled the acquisition of dynamic contrast-enhanced MR imaging, which is currently central to hepatic MR imaging for detection and characterization of liver tumors and is also useful for the evaluation of myometrial invasion in uterine cor-pus cancer. Advances in rapid T₂-weighted MR imaging with single-shot fast spin-echo images have enabled MR cholangiopancreatography and MR urography. Application of respiratory triggering can also provide T₂-weighted images of high quality. Cine MR imaging utilizing ultrafast MR sequences enables the assessment of the respiratory motion of the lung for evaluating thoracic wall invasion by tumors. Diffusion-weighted images can provide excellent tissue contrast based on molecular diffusion and have the potential to demonstrate malignant tumors. Quantitative measurement of apparent diffusion coefficient values may also be valuable in distinguishing malignancies from benign lesions.     

Prospective evaluation of pectoralis muscle invasion of breast cancer by MR imaging

BACKGROUND: Assessment of pectoralis muscle invasion is important for treatment planning for breast cancer. We evaluated the usefulness of breast magnetic resonance (MR) imaging for the detection of tumor invasion of the pectoralis muscle in breast cancer patients. MATERIALS AND METHODS: A total of 306 breast MR examinations were performed preoperatively. Three-dimensional gradient echo sequences, at a section thickness of 1.5 or 2 mm were obtained with administration of gadolinium-DTPA. All patients underwent surgery. RESULTS: In 33 breasts, disruption of the fat plane between tumor and muscle was noted. Seven of 33 cases showed muscle enhancement contiguous to enhanced tumors. Pathology reports indicated that 5 of 7 of the tumors involved muscle invasion. Of the 2 false positive cases, one showed muscle enhancement because of a previous biopsy, and the other was incorrectly interpreted as showing muscle enhancement. Of the 26 breasts which did not demonstrate muscle enhancement, none were found at surgery to have tumor involvement. CONCLUSION: Enhancement of the pectoralis muscle correlates well with muscle invasion, but there are a few potential pitfalls. Disruption of the fat plane between tumor and muscle, without muscle enhancement, might not indicate tumor involvement of the pectoralis muscle.     

磁共振扩散加权成像在肾细胞癌脑转移诊断中的应用

目的:探讨磁共振扩散加权成像（MRI DWI）在肾细胞癌（RCC）脑转移诊断中的应用价值。方法:采用回顾性研究方法分析2014年2月至2016年5月在我院诊治的140例RCC患者,所有患者都给予常规MRI T1WI与T2WI序列诊断,同时给予DWI序列的ADC值测定与诊断价值判定。结果:所有患者的MRI图像均显示清晰,病理确诊为RCC脑转移40例,RCC 100例。39例RCC脑转移患者的T2WI序列表现为高信号,36例T1WI序列表现为高信号;78例RCC患者的T2WI序列表现为高信号,72例T1WI序列表现为高信号,对比差异都有统计学意义（P＜0.05）。140例患者肾实质ADC值是（2.21±0.32）×10-3 mm2/s,同时,患者肾脏实性肿瘤ADC值是（1.54±0.37）×10-3 mm2/s,对比差异有统计学意义（t=4.298,P＜0.05）;RCC患者的ADC 值为（1.26±0.21）×10-3 mm2/s,RCC脑转移患者的ADC 值为（1.59±0.30）×10-3mm2/s,RCC脑转移的ADC 值明显高于RCC患者（P＜0.05）。将阈值设定为1.355×10-3 mm2/s,通过DWI对RCC患者的脑转移进行诊断,得出其特异性为92.1%,敏感性为85.0%。结论:在诊断RCC患者的脑转移时,ADC值和DWI可以提供重要依据,两者有很好的应用价值。     

Streptozotocin-induced renal tumours in rats.

Forty-six separate renal tumours developed in 36/80 Wistar male rats given a single i.v. dose of streptozotocin (25 mg/kg body wt) to induce diabetes mellitus. Fourteen of the tumours were epithelial in type, 8 were wholly mesenchymal and 24 were largely mesenchymal but also contained epithelial elements. The purely epithelial tumours correspond to the renal adenomas and adenocarcinomas seen in man. The mesenchymal tumours were composed either of undifferentiated spindle cells or of a mixutre of poorly differentiated mesenchyme and epithelial glands. Microscopically, the mixed tumours resembled the nephroblastomas seen in man; both elements appeared to be malignant, but in the absence of metastases this remains unproven. The management of the diabetic state did not influence the incidence of tumours, but insulin appeared to enhance tumour growth.     

Bone metastases in childhood renal tumours

Analysis of data from 1434 children with primary renal tumours revealed 57 who developed bone metastases. Of these, 54 were initially recorded as nephroblastoma. Fifty-two of the 57 cases were reviewed histologically, and only 18 were found to be Wilms' tumours. Twenty-three were classified as "Bone-Metastasizing Renal Tumour of Childhood" (BMRTC), and a high male incidence was found for these tumours (M:F=6.7:1). Differences in the pattern of metastasis and the one-year survival between BMRTC and nephroblastoma are discussed. The rarity of bone metastases from true Wilms' tumours is emphasized.