Interstitial MR lymphangiography for the detection of sentinel lymph nodes.

BACKGROUND AND OBJECTIVES: The challenge for implementation of sentinel lymph node biopsy is to develop a reliable minimally invasive technique that identifies all possible sentinel nodes with high temporal and spatial resolution. This study evaluated the use of a magnetic resonance imaging (MRI) contrast agent (USPIO) for preoperative sentinel node detection. METHODS: Anesthetized pigs received interstitial or intradermal injections of ultra small superparamagnetic of iron oxide (USPIO) (0.2 or 5 mg Fe) in the L/R posterior tongue and stifles (knee) respectively. MRI was done before, during injection and at 0.25, 0.5, 1, 2, 4, 6, 24, and 48 hr after which isosulfan blue sentinel node mapping was done. RESULTS: In the tongue, both doses of USPIO identified the sentinel node in the early images. No additional nodes were detected by MR at 24 or 48 hr. In the hind limb, sentinel nodes identified on the early MR images were also identified by the isosulfan blue. In both locations, the higher dose also identified secondary nodes some of which were also identified by the isosulfan blue. All sentinel nodes that were identified by USPIO on MRI were noted to be stained brown at the time of dissection. CONCLUSIONS: Interstitial MR lymphangiography is a useful technique for the detection of sentinel lymph nodes. This method provides excellent simultaneous temporal and spatial resolution, is minimally invasive, and can be performed preoperatively.     

Role of magnetic resonance imaging in the early diagnosis of Takayasu arteritis

Takayasu arteritis is a non‐specific inflammatory process of unknown aetiology affecting the aorta and its major branches. It may lead to stenosis or occlusion. We have examined eight patients with clinically diagnosed Takayasu arteritis using contrast‐enhanced MRI and also 3‐D MR angiography. All patients were female and their ages varied between 22 and 48 years. We were able to show subtle arteritic changes and stenotic lesions in branch vessels in the early phase of the disease by using this imaging modality. Thus, we can state that contrast‐enhanced MRI with 3‐D MR angiography can be used for the initial diagnosis of Takayasu arteritis. It provides a means to evaluate the vascular tree non‐invasively and may replace conventinal angiography.     

乳腺磁共振在乳腺癌诊断治疗中的运用

乳腺MRI具有很好的软组织分辨率和无射线辐射等优点,对乳腺癌的早期诊断和局部分期明显优于乳腺X线摄影和超声检查。随着乳腺癌个体化、规范化综合治疗理念的推广,乳腺MRI在综合治疗中的作用日益受到重视,伴随对乳腺MRI临床应用的开展和研究的深入,其在乳腺癌分期中的评估、保乳手术病例术前的筛选、腋窝淋巴结转移原发不明者的诊断、新辅助化疗(neoadjuvant chemotherapy, NAC)的疗效评估、随访监测中的应用价值也得到了很好的评估。同时,乳腺MRI对肿瘤范围的客观准确的评估也是正确选择治疗方式的依据。     

Updates in hepatic oncology imaging

The utilization of advanced imaging modalities play an important role in the detection and differentiation of benign and malignant hepatic lesions. Imaging characteristics of hepatic tumors can sometimes be atypical, often leading to diagnostic challenges. Recent technical improvements in contrast enhanced ultrasound (CEUS), computed tomography (CT), and magnetic resonance imaging (MRI) have helped to better characterize hepatic lesions. For example, contrast agents used in US can now better delineate liver lesions, while the ability to reliably produce multiplanar and 3-D reconstructions through the use of MDCT provides an additional advantage in the context of therapeutic decision making for patients with hepatic lesions. In addition, modern MR that includes the use of biliary excreted contrast material, various post-processing techniques like multiplanar reformation (MPR), as well as volume rendering (VR) allow detailed evaluation of the biliary tract, hepatic vasculature, and better characterization of hepatic tumors. As the imaging technologies available continue to evolve and advance, understanding how to effectively utilize these modalities is key to clinical practice. We herein provide a review of the various hepatic oncologic imaging modalities with a focus on how advancements and novel techniques within the different fields may be utilized in the diagnosis, treatment and management of different benign and malignant hepatic lesions.     

DCE-MRI parameters have potential to predict response of locally advanced breast cancer patients to neoadjuvant chemotherapy and hyperthermia: A pilot study

Combined therapies represent a staple of modern medicine. For women treated with neoadjuvant chemotherapy (NA ChT) for locally advanced breast cancer (LABC), early determination of whether the patient will fail to respond can enable the use of alternative, more beneficial therapies. This is even more desirable when the combined therapy includes hyperthermia (HT), an efficient way to improve drug delivery, however, more costly and time consuming. There is data showing that this goal can be achieved using magnetic resonance imaging (MRI) with contrast agent (CA) enhancement. This work for the first time proposes combining the information extracted from pre-treatment MR imaging into a morpho-physiological tumour score (MPTS) with the hypothesis that this score will increase the prognostic efficacy, compared to each of its MR-derived components: morphological (derived from the shape of the tumour enhancement) and physiological (derived from the CA enhancement variance dynamics parameters). The MPTS was correlated with response as determined by both pathologic residual tumour and MRI imaging, and was shown to have potential to predict response. The MPTS was extracted from pre-treatment MRI parameters, so independent of the combined therapy used.

Purpose: To use a novel morpho-physiological tumour score (MPTS) generated from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to predict response to treatment.

Materials and methods: A protocol was designed to acquire DCE-MRI images of 20 locally advanced breast cancer (LABC) patients treated with neoadjuvant chemotherapy (NA ChT) and hyperthermia (HT). Imaging was done over 30 min following bolus injection of gadopentetate-based contrast agent. Parametric maps were generated by fitting the signal intensity to a double exponential curve and were used to derive a morphological characterisation of the lesions. Enhancement-variance dynamics parameters, wash-in and wash-out parameters (WiP, WoP), were extracted. The morphological characterisation and the WiP and WoP were combined into a MPTS with the intent of achieving better prognostic efficacy. The MPTS was correlated with response to NA therapy as determined by pathological residual tumour and MRI imaging.

Results: The contrast agent in all tumours typically peaked in the first 1–4 min. The tumours’ WiP and WoP varied considerably. The MPTS was highly correlated with whether the patients had a pathological response. This scoring system has a specificity of 78% and a sensitivity of 91% for predicting response to NA chemotherapy. The kappa was 0.69 with a 95% confidence interval of [0.38, 1] and a p-value of 0.002.

Conclusions: This pilot study shows that the MPTS derived using pre-treatment MRI images has the potential to predict response to NA ChT and HT in LABC patients. Further prospective studies are needed to confirm the validity of these results.     

Non‐invasive in vivo imaging of early metabolic tumor response to therapies targeting choline metabolism

The cholinic phenotype, characterized by elevated phosphocholine and a high production of total‐choline (tCho)‐containing metabolites, is a metabolic hallmark of cancer. It can be exploited for targeted therapy. Non‐invasive imaging biomarkers are required to evaluate an individual's response to targeted anticancer agents that usually do not rapidly cause tumor shrinkage. Because metabolic changes can manifest at earlier stages of therapy than changes in tumor size, the aim of the current study was to evaluate ¹H‐MRS and diffusion‐weighted MRI (DW‐MRI) as markers of tumor response to the modulation of the choline pathway in mammary tumor xenografts. Inhibition of choline kinase activity was achieved with the direct pharmacological inhibitor H‐89, indirect inhibitor sorafenib and down‐regulation of choline‐kinase α (ChKA) expression using specific short‐hairpin RNA (shRNA). While all three strategies significantly decreased tCho tumor content in vivo, only sorafenib and anti‐ChKA shRNA significantly repressed tumor growth. The increase of apparent‐diffusion‐coefficient of water (ADCw) measured by DW‐MRI, was predictive of the induced necrosis and inhibition of the tumor growth in sorafenib treated mice, while the absence of change in ADC values in H89 treated mice predicted the absence of effect in terms of tumor necrosis and tumor growth. In conclusion, ¹H‐choline spectroscopy can be useful as a pharmacodynamic biomarker for choline targeted agents, while DW‐MRI can be used as an early marker of effective tumor response to choline targeted therapies. DW‐MRI combined to choline spectroscopy may provide a useful non‐invasive marker for the early clinical assessment of tumor response to therapies targeting choline signaling.     

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.     

MRI: Imaging of stomach

The study is to determine the optimal MRI bowel preparation regime for visualization of the stomach anatomy. Eight healthy volunteers were asked to take water, 75% barium and blueberry juice. The image quality and tolerance of different stomach distension regime were evaluated. Blueberry juice gave the best distension, but the signal intensity was not very homogeneous. Taking into account the image quality, tolerability and adverse effects, it is concluded that water is the most desirable oral contrast for MR stomach imaging.     

The evaluation of human breast lesions with magnetic resonance imaging and proton magnetic resonance spectroscopy

Purpose. MR spectroscopy (MRS) assists in lesion characterization and diagnosis when combined with magnetic resonance imaging (MRI). Cancerous lesions demonstrate elevated composite choline levels arising from increased cellular proliferation. Our study investigated if MR spectroscopy of the breast would be useful for characterizing benign and malignant lesions. Materials and methods. Single voxel proton MR spectroscopy (MRS) was acquired as part of an MR imaging protocol in 38 patients referred upon surgical consultation. The MR spectra were read independently in a blinded fashion without the MR images by three spectroscopists. The MRI exam was interpreted in two settings: (a) as a clinical exam with detailed histories and results from previous imaging studies such as mammography or ultrasound included and (b) as a blinded study without prior histories or imaging results. Results. Elevated choline levels were demonstrated by MRS in 19 of the 23 confirmed cancer patients. The sensitivity and specificity for determining malignancy from benign breast disease with MRS alone were 83 and 87%, respectively, while a blinded MRI review reported 95 and 86%, respectively. Conclusions. Proton MR spectroscopy provides a noninvasive, biochemical measure of metabolism. The technique can be performed in less than 10min as part of an MRI examination. MRI in combination with MRS may improve the specificity of breast MR and thereby, influence patient treatment options. This may be particularly true with less experienced breast MRI readers. In exams where MRI and MRS agree, the additional confidence measure provided by MRS may influence the course of treatment.     

乳腺癌的MRI诊断

MRI是乳腺癌的一种新的、重要的检查方法。增强MRI对侵袭性乳腺癌具有很高的敏感性。MRI对乳腺癌手术方案的制订、鉴别复发起到重要作用。就MRI和其他检查方法在乳腺癌诊断方面的应用比较予以综述。     

Magnetic resonance imaging in breast cancer: A literature review and future perspectives

Early detection and diagnosis of breast cancer are essential for successful treatment. Currently mammography and ultrasound are the basic imaging techniques for the detection and localization of breast tumors. The low sensitivity and specificity of these imaging tools resulted in a demand for new imaging modalities and breast magnetic resonance imaging (MRI) has become increasingly important in the detection and delineation of breast cancer in daily practice. However, the clinical benefits of the use of pre-operative MRI in women with newly diagnosed breast cancer is still a matter of debate. The main additional diagnostic value of MRI relies on specific situations such as detecting multifocal, multicentric or contralateral disease unrecognized on conventional assessment (particularly in patients diagnosed with invasive lobular carcinoma), assessing the response to neoadjuvant chemotherapy, detection of cancer in dense breast tissue, recognition of an occult primary breast cancer in patients presenting with cancer metastasis in axillary lymph nodes, among others. Nevertheless, the development of new MRI technologies such as diffusion-weighted imaging, proton spectroscopy and higher field strength 7.0 T imaging offer a new perspective in providing additional information in breast abnormalities. We conducted an expert literature review on the value of breast MRI in diagnosing and staging breast cancer, as well as the future potentials of new MRI technologies.     

Preoperative breast magnetic resonance imaging in early breast cancer

BACKGROUND:

Accelerated partial breast irradiation (APBI) of patients with early breast cancer is being investigated on a multi‐institutional protocol National Surgical Adjuvant Breast and Bowel Project (NSABP) B‐39/RTOG 0413. Breast magnetic resonance imaging (MRI) is more sensitive than mammography (MG) and may aid in selection of patients appropriate for PBI.

METHODS:

Patients with newly diagnosed breast cancer or ductal carcinoma in situ (DCIS) routinely undergo contrast‐enhanced, bilateral breast MRI at the Cleveland Clinic. We retrospectively reviewed the medical records of all early‐stage breast cancer patients who had a breast MRI, MG, and surgical pathology data at our institution between June of 2005 and December of 2006. Any suspicious lesions identified on MRI were further evaluated by targeted ultrasound ± biopsy.

RESULTS:

A total of 260 patients met eligibility criteria for NSABP B‐39/RTOG 0413 by MG, physical exam, and surgical pathology. The median age was 57 years. DCIS was present in 63 patients, and invasive breast cancer was found in 197 patients. MRI identified suspicious lesions in 35 ipsilateral breasts (13%) and in 16 contralateral breasts (6%). Mammographically occult, synchronous ipsilateral foci were found by MRI in 11 patients (4.2%), and in the contralateral breast in 4 patients (1.5%). By univariate analysis, lobular histology (infiltrating lobular carcinoma [ILC]), pathologic T2, and American Joint Committee on Cancer stage II were significantly associated with additional ipsilateral disease. Of patients with ILC histology, 18% had ipsilateral secondary cancers or DCIS, compared with 3% in the remainder of histologic subtypes (P = .004). No patient older than 70 years had synchronous cancers or DCIS detected by MRI.

CONCLUSIONS:

Breast MRI identified synchronous mammographically occult foci in 5.8% of early breast cancer patients who would otherwise be candidates for APBI. Cancer 2009. © 2009 American Cancer Society.     

肿瘤靶向磁共振成像研究进展

以恶性肿瘤细胞或肿瘤组织表达的特定分子为靶点,采用相应的分子探针载体连接铁类或钆类磁共振对比剂,即磁共振肿瘤靶向对比剂.用于孵育体外培养的肿瘤细胞,以及经静脉注射到载瘤裸鼠体内.近年来许多研究者证实磁共振成像(MRI)能观察该类肿瘤靶向对比剂的靶向效果,有望实现恶性肿瘤的磁共振定性诊断,检测肿瘤靶向治疗效果,并指导临床选择合适的靶向化疗药.     

Functional imaging: what evidence is there for its utility in clinical trials of targeted therapies?

Key issues in early clinical trials of targeted agents include the determination of target inhibition, rational patient selection based on pre-treatment tumour characteristics, and assessment of tumour response in the absence of actual shrinkage. There is accumulating evidence that functional imaging using advanced techniques such as dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI), DCE-computerised tomography (CT) and DCE-ultrasound, diffusion weighted-MRI, magnetic resonance spectroscopy and positron emission tomography-CT using various labelled radioactive tracers has the potential to address all three. This article reviews this evidence with examples from trials using targeted agents with established clinical efficacy and summarises the clinical utility of the various techniques. We therefore recommend that input from specialist radiologists is sought at the early stages of trial design, in order to ensure that functional imaging is incorporated appropriately for the agent under study. There is an urgent need to strengthen the evidence base for these techniques as they evolve, and to ensure standardisation of the methodology.     

Intramammary extension of breast cancer: Diagnosis with MR mammography

Purpose  Intramammary extension of breast cancer was investigated using contrast-enhanced magnetic resonance (MR) imaging by comparing MR findings with the histopathology of specimens used for pretreatment planning. Materials and Methods  Thirty-nine breast cancers were examined. The dynamic protocol was performed with a 2- or 3-dimensional fast spin echo sequence (1.5 T), once before and 2-5 times immediately after Gd-DTPA administration with an original fat suppression technique. The findings were correlated with the histopathology. Results  All main tumors showed early enhancement. All with direct invasion histopathologically showed spicular enhancement. The four patients who had separate nodular enhancement showed satellite lesions histopathologically. Three-typed MR findings were found to be indicative of an intraductal component. Conclusion  Various forms of breast cancer were reliably demonstrated using MR imaging. MR imaging could be useful for the pretreatment planning for patients with breast cancer.     

MR Imaging of the primary breast lymphoma: A case report

Recently magnetic resonance (MR) imaging has been investigated for the detection and differentiation of benign and malignant breast lesions. Dynamic scan using the contrast material has been shown to increase the specificity of breast MR imaging. Primary breast lymphoma (PBL) is a rare disease and its MR imaging finding has not been described before. We recently experienced a case of PBL that was demonstrated on MR imaging as an early enhancing mass similar to common carcinomas. Other imaging findings including sonography, mammography were also non-specific. Furthermore, lymphoma cells had spread beyond the early enhanced area. Thus the precise delineation of the tumor extent was impossible. However, features such as a quite unclear border on pre-contrast T2-weighted image, and increased uptake of gallium-67-citrate may allow diagnosis of such lesions as malignant lymphoma.     

Current applications and future direction of MR mammography

Compared with triple assessment for symptomatic and occult breast disease, magnetic resonance mammography (MRM) offers higher sensitivity for the detection of multifocal cancer, which is important in selecting patients appropriately for breast-conserving surgery. It is an ideal tool for the screening of patients with a high risk of breast cancer or where there is axillary disease or nipple discharge and conventional imaging has not revealed the primary focus. Techniques are now available to biopsy lesions only apparent on MRM. MRM can differentiate scar tissue from tumour; therefore, it is useful in patients in which there is possible recurrent disease. Clinical and X-ray mammographic assessment of response to neoadjuvant chemotherapy may be unreliable because of replacement of the tumour with scar tissue. MRM can identify responders and nonresponders with more accuracy. It is the modality of choice for the assessment of breast implants for rupture with accuracy higher than X-ray mammography and ultrasound. Advances in both spatial and temporal resolutions, the imaging sequences employed, pharmacokinetic modelling of contrast uptake, the use of dedicated and now phased-array breast coils, and gadolinium-based contrast agents have all played their part in the advancement of this imaging technique. Despite the limitations of patient compliance, scan-time and cost, this review describes how MRM has become a valuable tool in breast disease, especially in cases of diagnostic uncertainty. However, MRM must make the transition from research institutions into routine clinical practice.     

Assessment of abdominal aortic aneurysm with magnetic resonance imaging

Pre-operative imaging of abdominal aortic aneurysms (AAA) is important in determining suitability for operation and operative approach. Ultrasound imaging is an excellent screening modality but is relatively poor at identifying renal arteries and the extent of iliac involvement. Computed tomography scanning with intravenous contrast and arteriography are invasive modalities that are associated with a small risk. Magnetic resonance imaging (MRI) offers the potential of accurate anatomical definition without use of contrast agents and passage of an intra-arterial catheter. Eight patients who had their AAA evaluated with MRI are reported. All had renal arteries accurately defined, intraaneurysmal thrombosis was well delineated, and iliac extension was correctly identified in four cases. The initial experience has been most encouraging and the authors consider that MRI may become the investigation of choice for pre-operative AAA assessment.     

Magnetic resonance imaging in patients with newly diagnosed breast cancer: A review of the literature

The use of magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer remains controversial. Here we review the current use of breast MRI and the impact of MRI on short‐term surgical outcomes and rates of local recurrence. In addition, we address the use of MRI in specific patient populations, such as those with ductal carcinoma in situ, invasive lobular carcinoma, and occult primary breast cancer, and discuss the potential role of MRI for assessing response to neoadjuvant chemotherapy. Although MRI has improved sensitivity compared with conventional imaging, this has not translated into improved short‐term surgical outcomes or long‐term patient benefit, such as improved local control or survival, in any patient population. MRI is an important diagnostic test in the evaluation of patients presenting with occult primary breast cancer and has shown promise in monitoring response to neoadjuvant chemotherapy; however, the data do not support the routine use of perioperative MRI in patients with newly diagnosed breast cancer. Cancer 2014;120:120:2080–2089. © 2014 American Cancer Society.     

MRI in ankle tuberculosis: Review of 14 cases

We reviewed the MR imaging features of ankle tuberculosis and determined the role of MR in its diagnosis. A retrospective analysis of 14 cases of ankle tuberculosis imaged with MRI was performed. Plain radiographs were also reviewed where available, and the imaging characteristics were noted. We also reviewed the medical records in order to assess the impact of the imaging findings on management of these patients. Magnetic resonance imaging is extremely helpful for detection, mapping the extent and resolution of the disease. It can identify cases, enables early institution of antituberculous chemotherapy and might obviate the need for surgery.