New advances in brain tumor imaging

During the period of this review, there has been continued use and development of neuroimaging techniques in brain tumor diagnosis and management. Although no monumental developments or improvements in neuroimaging techniques or technology have occurred, important studies continue to be published showing the clinical impact and utility of various neuroimaging techniques to improve the care of patients with brain tumors. Several studies have shown the power of functional neuroimaging techniques with both magnetic resonance imaging (MRI) and positron-emission tomography (PET) to map eloquent cortex and assist in the planning of surgical and radiation therapy. New nuclear imaging radiopharmaceuticals, including various PET ligands and single photon emission computed tomography (SPECT) agents, have also been developed and show their potential power in the evaluation of brain tumor patients. New MRI pulse sequences to improve image quality and shorten imaging time have also been developed. Several excellent reviews of the use of fluorodeoxyglucose (FDG)-PET and MRI techniques were also published. This article reviews the relevant and important neuroimaging literature related to brain tumor that was published during the defined time period of November 1, 1999 to October 31, 2000. Discussion is organized by modality, including nuclear imaging techniques (SPECT and PET) and MRI (pulse sequence development, contrast agent development, functional MRI developments, and general MRI-related information).     

Advances in neurosurgical technique in the current management of brain tumors

Despite significant advances in anatomical and functional neuroimaging modalities (eg, magnetic resonance [MR] imaging [MRI], MR spectroscopy [MRS], diffusion and perfusion MR, functional MRI [fMRI], magnetic-source imaging [MSI], diffusion tensor imaging [DTI]) and neuronavigation techniques, intraoperatively obtained functional information remains of crucial importance to the neurosurgeon, especially when operating on tumors that are located in or adjacent to functional cortical sites and subcortical pathways. This article focuses on recent advances in the surgical management of of intracerebral tumors with special emphasis on intraoperative cortical and subcortical stimulation mapping methods, and the prognostic significance of surgery on patient outcome.     

31例以突发听力下降为首发症状的小听神经瘤的临床分析

目的:探讨以突发听力下降为首发症状的小听神经瘤的临床特点，以期提高临床诊治水平。方法:回顾性分析2015年12月至2017年12月31例以突发听力下降为首发症状的小听神经瘤患者，观察其在听力学检查和影像学检查方面情况。结果:听力检查上，纯音测听主要表现为轻中度，占全部的74.19%， 声导抗检查，镫骨肌声反射阳性发生率为35.48%，高刺激ABR阳性发生率为83.87%，前庭功能检查正常的占多数，为全部的67.74%。MRI影像学诊断率为100%，其中17例患者表现为双侧听神经形态不对称，5例骨质破坏，6例周围粘连，3例表现为囊变、肿瘤包膜形成。31例患者中无听力水平恢复至正常或病前水平者，9例患者耳鸣和平衡失调症状缓解，5例患者听力有所改善，眩晕等不适未出现，远期疗效为逐渐进展性。结论:对以突发听力下降为首发症状的可疑的小听神经瘤患者要进行听力检查，必要时进行颞骨CT和MRI检查。     

Head and neck cancer as a model for advances in imaging prognosis, early assessment, and posttherapy evaluation

Novel noninvasive functional imaging methods are necessary to predict therapeutic outcome and thereby improve the ability to properly select patients for treatment with both conventional and targeted therapies, to better evaluate therapeutic effectiveness during the early phases of treatment, and to enhance a priori risk assessment for treatment induced toxicity. Functional metabolic imaging typically involves pretreatment baseline magnetic resonance imaging (MRI) and/or positron emission tomographic (PET) scans and performance of subsequent scans during and/or after treatment. Imaging parameter changes are routinely attributed to the intervening therapy and clinical outcomes subsequently correlated with these changes. The physiologic parameter(s) that best correlate with clinical outcome and the relative utility of MRI versus PET are unknown, however. Furthermore, tumor vascular physiology and metabolic parameters are heterogeneous and dynamic processes. Large daily fluctuations often occur in the absence of treatment. The magnitude of this temporal variability is not established for MRI or for PET. Routine and meaningful clinical application of functional imaging requires understanding and quantification of the intrinsic variability of the underlying biologic processes and a demonstration that treatment-induced changes exceed intrinsic temporal variation.     

Impacts of neuroimaging on psycho-oncology

Non-invasive neuroimaging has become important in the field of psycho-oncology. Positron emission tomography (PET) is a highly advanced form of scintigraphy and used for observation of regional tissue activities such as metabolism and perfusion. Nowadays, PET measurement of glucose consumption has been widely used not only for cancer diagnosis but also for evaluation of brain activity in various psychiatric and neurological disorders. Recently, it has been used for evaluation of relatively mild depression among cancer patients. In addition, magnetic resonance imaging (MRI) has been used for detection of brain metastasis in cancer patients, but also useful for evaluation of stressful events by measuring the sizes of tiny neural structures such as hippocampus and amygdala.In this report, recent findings of non-invasive neuroimaging in cancer patients are overviewed, putting emphasis on the possible impacts of neuroimaging on psycho-oncology.     

Quel bilan d’imagerie avant une radiothérapie de rattrapage après prostatectomie radicale pour adénocarcinome prostatique ?

Prostatectomy is one of the most widely used methods for treatment of adenocarcinoma of the prostate. According to anatomopathological criteria, between 10 and 40% of patients will display biochemical relapse in the absence of adjuvant radiotherapy. Anatomopathological and biochemical criteria are powerful tools for selecting patients for salvage radiotherapy. The aim of this article is to review literature on the latest progress in radiological and nuclear medicine techniques and their performance levels, in order to determine local, regional and metastatic relapses associated with the techniques and specify the radiotherapy target volume. Magnetic resonance imaging (MRI) displays the best sensitivity and specificity for examination of the prostate bed and enables simultaneous assessment of the pelvic region – thus diminishing the utility of computed tomography. The performance levels of MRI will probably continue to improve, with the use of dynamic MRI and MR spectroscopy. Despite the development of new markers like ¹¹C and ¹⁸F choline and acetate, the sensitivity of positron emission tomography is still low. Prospective studies with an appropriate methodology are necessary for specifying the technique's value in this context.     

Auditory pattern in deafness following meningococcal meningitis

Thirty cases complaining of hearing loss following the attack of meningococcal meningitis during its epidemic in Delhi, between March ’85 and July ’85, were taken up for audiological study. Different audiological tests including pure tone audiometry and auditory brainstem response (ABR) were done at regular intervals for 2 J years in such sixty ears of thirty cases. The influence of different factors on the auditory outcome like, the age of patient, the duration of disease prior to hearing loss and the severity of initial hearing loss, have been discussed.     

Imaging features of Benign Perianal lesions

Magnetic resonance imaging provides detailed visualisation, identification and extent assessment of many anal disorders. While many studies are performed in the evaluation of malignant processes such as anorectal carcinoma, the primary focus of this pictorial review is benign lesions, which involve the anal canal and perianal spaces. This pictorial review will illustrate the MRI appearances of a variety of benign conditions, which predominantly affect the anal canal, including abscess, fistulae, lipomas, developmental cysts and inflammatory conditions. MRI aids in the identification and characterisation of these abnormalities, of coexisting complications and differentiation from other perineal abnormalities. This pictorial review highlights the spectrum of non‐malignant processes involving the perianal region.     

Magnetic resonance tomography: potentials of molecular imaging

Molecular imaging is "the in-vivo characterization and measurement of biological processes at the cellular and molecular level" and allows the imaging of molecular abnormalities associated with diseases long before morphological changes can be detected. At present, the use of magnetic resonance imaging (MRI) for molecular and cellular imaging is rapidly increasing. MRI is a very attractive candidate, since current MRI protocols already provide anatomic, functional, and biochemical information of excellent image quality and with high spatial resolution. Combining this high spatial resolution/high contrast imaging modality with specific MRI contrast imaging agents for molecular imaging is currently the focus of research in many laboratories worldwide. This paper summarizes the rationale for molecular MRI imaging and describes the basic features of modern molecular imaging strategies with MRI. Finally, a special focus is given to the growing field of applications, e.g., stem cell imaging, imaging of apoptosis, plaques, and other biological targets of interest.     

Speech Evoked Auditory Brainstem Responses: A New Tool to Study Brainstem Encoding of Speech Sounds

The neural encoding of speech sound begins in the auditory nerve and travels to the auditory brainstem. Non speech stimuli such as click or tone bursts stimulus are used to check the auditory neural integrity routinely. Recently Speech evoked Auditory Brainstem measures (ABR) are being used as a tool to study the brainstem processing of Speech sounds. The aim of the study was to study the Speech evoked ABR to a consonant vowel (CV) stimulus. 30 subjects with normal hearing participated for the study. Speech evoked ABR were measured to a CV stimulus in all the participants. The speech stimulus used was a 40 ms synthesized/da/sound. The consonant and vowel portion was analysed separately. Speech evoked ABR was present in all the normal hearing subjects. The consonant portion of the stimulus elicited peak V in response waveform. Response to the vowel portion elicited a frequency following response (FFR). The FFR further showed a coding of the fundamental frequency (F0) and the first formant frequency (F1). The results of the present study throw light on the processing of speech in brainstem. The understanding of speech evoked ABR has other applications both in research as well as in clinical purposes. Such understanding is specially important if one is interested in studying the central auditory system function.     

The importance of MRI for rectal cancer evaluation

Magnetic resonance imaging (MRI) has gained increasing importance in the management of rectal cancer over the last two decades. The role of MRI in patients with rectal cancer has expanded beyond the tumor-node-metastasis (TNM) system in both staging and restaging scenarios and has contributed to identifying “high” and “low” risk features that can be used to tailor and personalize patient treatment; for instance, selecting the patients for neoadjuvant chemoradiation (NCRT) before the total mesorectal excision (TME) surgery based on risk of recurrence. Among those features, the status of the circumferential resection margin (CRM), extramural vascular invasion (EMVI), and tumor deposits (TD) have stood out. Moreover, MRI also has played a role in surgical planning, especially when the tumor is located in the low rectum, when the relationship between tumor and the anal canal is important to choose the best surgical approach, and in cases of locally advanced or recurrent tumors invading adjacent pelvic organs that may require more complex surgeries such as pelvic exenteration. As approaches using organ preservation emerge, including transanal local excision and “watch-and-wait”, MRI may help in the patient selection for those treatments, follow up, and detection of tumor regrowth. Additionally, potential MRI-based prognostic and predictive biomarkers, such as quantitative and semi-quantitative metrics derived from functional sequences like diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE), and radiomics, are under investigation. This review provides an overview of the current role of MRI in rectal cancer in staging and restaging and highlights the main areas under investigation and future perspectives.     

Bildgebende Diagnostik des Nierenzellkarzinoms

There is an increasing tendency of incidental detection of renal cell carcinoma (RCC) in imaging studies performed for other purposes. In most instances multi-detector computerized tomography (MDCT) is the current investigation of choice for confirmation of diagnosis and staging of the primary RCC. Exceptional circumstances where alternative imaging modalities, such as magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), would be preferred include contrast medium allergy, functional renal impairment and pregnancy. MRI provides excellent soft tissue contrast facilitating evaluation of tumor composition and characterization of masses. Besides identifying these incidental lesions, diagnostic imaging plays an increasingly more prominent clinical role and supports the need for accurate imaging characterization, particularly in the context of newer therapeutic approaches, such as laparoscopic and nephron-sparing approaches. Staging systems are designed to reflect the modes of spread and are used to stratify treatment options and to assess prognosis and survival characteristics.     

Diffusion and perfusion MR imaging

Diffusion (DWI) and perfusion weighted (PWI) MR imaging, have come to have an increasingly important clinical role, especially in neurovascular imaging. Diffusion MR imaging does not evaluate hemodynamic parameters, but can be considered a functional technique because it provides information about the tissue functional structure at a microscopic level. In this technique, image contrast to a large extent depends on the diffusion coefficient, a parameter indicative of the characteristics of the stochastic thermic translational motion of water molecules (Brownian motion). Clinical perfusion measurement has been performed in almost all organs with different techniques. Over the last ten years, with the use of contrast media, considerable experience has been gained in the measurement of hemodynamics with MRI. At present, perfusion-MR imaging is one of the clinically most relevant procedures of functional MRI, whose application is gaining ground, owing to the increasing availability of necessary hardware and software. Physical and hemodynamic principles of the two techniques, pulse sequences necessary for their implementation and main applications in the imaging of CNS disorders are illustrated. While DWI and PWI alone can address numerous questions, their information is for the most part complementary to that provided by conventional MRI and their combination seems extremely promising.     

Imagerie fonctionnelle du sein

In recent years, breast imaging has benefited from a number of new advances. The resulting new imaging methods mainly focus on the functional examination of tumours and aim to improve tumour detection and characterization, provide new prognosis criteria, and guide the therapeutic management of breast cancer. One of the most promising functional assessments — whether performed through the use of ultrasound, X-rays or MRI — is the analysis of tumour angiogenesis, which plays a major role in tumour development and metastatic potential. In this article, we discuss the major developments in functional imaging of the breast, including imaging methods such as X-rays, ultrasound, MRI and nuclear medicine. After a brief technology overview, we present the early clinical results and prospects of each of the techniques.     

Models for Assessment of Angiogenesis in Gliomas

In the last two decades, much attention has been focussed on mechanisms of glioma vascularization including the investigation of growth factors and receptors involved. Recently, these efforts resulted in various approaches for antiangiogenic treatment of experimental brain tumors. These basic science and preclinical trials need an assortment of models, which should allow investigating a variety of questions. Several objectives concerning basic endothelial cell (EC) characteristics can adequately be studied in vitro using EC monolayer assays. Three-dimensional spheroid techniques respect the more complex cell–cell and cell–environment interplay within a three-dimensional culture. To optimize the imitation of the crucial interaction of human gliomas with host endothelial cells, immunological cells and extracellular matrix, animal models are mandatory. An essential rule is to utilize an orthotopic model, since tumor–host interaction is organ specific. To avoid alloimmunogenic responses, it is desirable to use weakly or not immunogenic glioma grafts, what is best accomplished in a syngeneic model. However, since rat gliomas poorly resemble human glioma growth patterns, human glioma xenografting into immunocompromized animals should be considered. In vivo monitoring techniques like videoscopy via a cranial window or magnetic resonance imaging (MRI) allow for functional studies and improve the validity of the model employed. Finally, it is essentially to recognize the limitations of each model considered and to select that model, which seems to be most appropriate for the objectives to be investigated.     

Investigation of the usability of conebeam CT data sets for dose calculation

Radiation medicine has previously utilized planning methods based primarily on anatomic and volumetric imaging technologies such as CT (Computerized Tomography), ultrasound, and MRI (Magnetic Resonance Imaging). In recent years, it has become apparent that a new dimension of non-invasive imaging studies may hold great promise for expanding the utility and effectiveness of the treatment planning process. Functional imaging such as PET (Positron Emission Tomography) studies and other nuclear medicine based assays are beginning to occupy a larger place in the oncology imaging world. Unlike the previously mentioned anatomic imaging methodologies, functional imaging allows differentiation between metabolically dead and dying cells and those which are actively metabolizing. The ability of functional imaging to reproducibly select viable and active cell populations in a non-invasive manner is now undergoing validation for many types of tumor cells. Many histologic subtypes appear amenable to this approach, with impressive sensitivity and selectivity reported. For clinical radiation medicine, the ability to differentiate between different levels and types of metabolic activity allows the possibility of risk based focal treatments in which the radiation doses and fields are more tightly connected to the perceived risk of recurrence or progression at each location. This review will summarize many of the basic principles involved in the field of functional PET imaging for radiation oncology planning and describe some of the major relevant published data behind this expanding trend.     

Hybrid Imaging in Oncology

In oncology various imaging modalities play a crucial role in diagnosis, staging, restaging, treatment monitoringand follow up of various cancers. Stand-alone morphological imaging like computerized tomography (CT) andmagnetic resonance imaging (MRI) provide a high magnitude of anatomical details about the tumor but arerelatively dumb about tumor physiology. Stand-alone functional imaging like positron emission tomography(PET) and single photon emission tomography (SPECT) are rich in functional information but provide littleinsight into tumor morphology. Introduction of first hybrid modality PET/CT is the one of the most successfulstories of current century which has revolutionized patient care in oncology due to its high diagnostic accuracy.Spurred on by this success, more hybrid imaging modalities like SPECT/CT and PET/MR were introduced. Itis the time to explore the potential applications of the existing hybrid modalities, developing and implementingstandardized imaging protocols and train users in nuclear medicine and radiology. In this review we discussthree existing hybrid modalities with emphasis on their technical aspects and clinical applications in oncology.     

Application of magnetic resonance imaging to angiogenesis in breast cancer

Magnetic resonance imaging (MRI) techniques enable vascular function to be mapped with high spatial resolution. Current methods for imaging in breast cancer are described, and a review of recent studies that compared dynamic contrast-enhanced MRI with histopathological indicators of tumour vascular status is provided. These studies show correlation between in vivo dynamic contrast measurements and in vitro histopathology. Dynamic contrast-enhanced MRI is also being applied to assessment of the response of breast tumours to treatment.     

Microstructure of the lung: diffusion measurement of hyperpolarized 3Helium

Imaging methods to study the lung are traditionally based on x-ray or on radioactive contrast agents. Conventional magnetic resonance imaging (MRI) has only limited applications for lung imaging because of the low tissue density of protons concentration of hydrogen atoms, which are usually the basis for the imaging. The introduction of hyperpolarized noble gases as a contrast agent in MRI has opened new possibilities for lung diagnosis. The present paper describes this new technique. Diffusion-weighted MRI for assessment of the lung microstructure is presented here as an example of the new possibilities of functional imaging. Studies to determine the sensitivity of the diffusion measurement and regarding the correlation with traditionally established methods are also presented, along with results of the measurement of the reproducibility determined in a clinical pilot study on healthy volunteers and patients. Furthermore, a pilot measurement of the 3He diffusion tensor in the lung is presented.