Basic Imaging Techniques Research Articles

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.

An introduction to molecular imaging in radiation oncology: A report by the AAPM Working Group on Molecular Imaging in Radiation Oncology (WGMIR)

Molecular imaging is the direct or indirect noninvasive monitoring and recording of the spatial and temporal distribution of in vivo molecular, genetic, and/or cellular processes for biochemical, biological, diagnostic, or therapeutic applications. Molecular images that indicate the presence of malignancy can be acquired using optical, ultrasonic, radiologic, radionuclide, and magnetic resonance techniques. For the radiation oncology physicist in particular, these methods and their roles in molecular imaging of oncologic processes are reviewed with respect to their physical bases and imaging characteristics, including signal intensity, spatial scale, and spatial resolution. Relevant molecular terminology is defined as an educational assist. Current and future clinical applications in oncologic diagnosis and treatment are discussed. National initiatives for the development of basic science and clinical molecular imaging techniques and expertise are reviewed, illustrating research opportunities in as well as the importance of this growing field.

A Historical Overview of Magnetic Resonance Imaging, Focusing on Technological Innovations

Magnetic resonance imaging (MRI) has now been used clinically for more than 30 years. Today, MRI serves as the primary diagnostic modality for many clinical problems. In this article, historical developments in the field of MRI will be discussed with a focus on technological innovations. Topics include the initial discoveries in nuclear magnetic resonance that allowed for the advent of MRI as well as the development of whole-body, high field strength, and open MRI systems. Dedicated imaging coils, basic pulse sequences, contrast-enhanced, and functional imaging techniques will also be discussed in a historical context. This article describes important technological innovations in the field of MRI, together with their clinical applicability today, providing critical insights into future developments.

WE-C-218-01: Ultrasound Contrast Agents.

1. Understand the basic principles of ultrasound contrast agents a. What are microbubble contrast agents? b. Properties of microbubbles c. Safety concerns and biological effects 2. Understand basic contrast imaging techniques a. Harmonic and suharmonic imaging techniques b. Pulse inversion techniques 3. Understand the use of contrast agents in various vascular applications a. Traditional methods (Cardiovascular, Abdominal) b. Advanced perfusion imaging techniques 4. Understand the role of contrast agents in preclinical applications a. Ultrasound molecular imaging b. Gene therapy c. Drug delivery d. Acoustic angiography.

Imaging to optimize liver tumor ablation.

Surgical resection remains the ideal treatment for hepatocellular carcinoma and metastasis to the liver. Many alternatives are available for treatment of nonsurgical candidates. Regardless of treatment, optimizing imaging in the pretreatment, treatment and post-treatment settings is critical in order to lower the rates of local tumor progression and maximize the effectiveness of treatment that may result in prolonged survival. This article summarizes some basic imaging techniques of primary and metastatic liver tumors with a focus on how to optimize their treatment with ablation.

Kliniczna ocena tomografii komputerowej nosa i zatok przynosowych

Computed tomography is a basic imaging technique in nose and paranasal sinuses disease's nowadays. The aim of the study was to outline current methodology of CT scanning of nose and paranasal sinuses. This study is based on the experience of Department of Otorhinolaryngology of Medical University of Lódź in evaluation by CT scanning patients with nose/paranasal sinuses problems and on the literature concerning this problem. Pictures in three planes (axial, coronal, sagittal) are obtained from multi-row CT scanner. However in some cases 3D reconstructions are useful. The thickness of the single layer is 0.625 or 1 mm. In case of tumor suspicion contrast CT scanning is a routine procedure. The analysis of pictures is preceded by anamnesis and careful rhinologic examination. Coronal scans are evaluated as first and they are divided into four zones (frontal sinus, anterior ethmoid cells, posterior ethmoid cells and sphenoid sinus zones) for more systematic analysis. Then axial and sagittal scans are examined. Every single structure and its anatomical variations are named by using current terminology outlined during International Conference of Sinus Disease in Princeton in 1993 by The Anatomic Terminology Group. Quality and quantity of the information from CT of nose and paranasal sinuses depends on keeping some rules concerning the stage of performing the examination and the stage of its evaluation and applying current anatomic terminology.

Sister Mary Joseph’s nodule as the first sign of pregnancy-associated gastric cancer: A case report

Sister Mary Joseph's nodule is an inconspicuous and uncommon clinical sign of advanced malignant disease, especially gastric cancer. Pregnancy-associated gastric cancer is an extremely rare condition and can be difficult to diagnose, due to the absence or misinterpretation of symptoms as pregnancy-related. Diagnostic aids, such as a basic chemistry panel and imaging techniques, may not show any abnormalities. We present a case of a 37-year-old pregnant patient whose umbilical nodule was the first presenting physical sign of gastric cancer, which had metastasized throughout the abdominal and pelvic regions.

Magnetic resonance imaging of cartilage glycosaminoglycan: Basic principles, imaging technique, and clinical applications

Many new therapeutic strategies have been and are being developed to prevent, correct, or slow the progression of osteoarthritis. Our ability to evaluate the efficacy of these techniques, or to determine the situations for which they might provide the most benefit, critically depends on diagnostic measures that can serve as proxies for the present or predicted state of the cartilage. We focus here on a body of work surrounding the development of magnetic resonance imaging (MRI) techniques to noninvasively image the glycosaminoglycan (GAG) concentration of articular cartilage. These techniques are based on the concept of fixed charge in cartilage resulting from the glycosaminoglycans. Starting with sodium MRI, and the subsequent development of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) based on proton MRI, these techniques permit "visualization" of the charged GAG distribution in cartilage in vitro or in vivo. The dGEMRIC technique has been used in preliminary clinical studies to understand treatment strategies and to monitor disease, and as such is allowing studies that a decade ago would have been impossible. This new technical capability offers the promises of speeding development of effective therapies and focusing their use in areas where they can be most successful.

A Graphical Simulator for Teaching Basic and Advanced MR Imaging Techniques

Teaching of magnetic resonance (MR) imaging techniques typically involves considerable handwaving, literally, to explain concepts such as resonance, rotating frames, dephasing, refocusing, sequences, and imaging. A proper understanding of MR contrast and imaging techniques is crucial for radiologists, radiographers, and technical staff alike, but it is notoriously challenging to explain spin dynamics by using traditional teaching tools. The author developed a freely available graphical simulator based on the Bloch equations to aid in the teaching of topics ranging from precession and relaxation to advanced concepts such as stimulated echoes, spin tagging, and k-space-methods. A graphical user interface provides the user with a three-dimensional view of spin isochromates that can be manipulated by selecting radiofrequency pulses and gradient events. Even complicated sequences can be visualized in an intuitive way. The cross-platform software is primarily designed for use in lectures, but is also useful for self studies and student assignments. Movies available at http://radiographics.rsnajnls.org/cgi/content/full/e27/DC1.

An Introduction to Na18F Bone Scintigraphy: Basic Principles, Advanced Imaging Concepts, and Case Examples

Na(18)F, an early bone scintigraphy agent, is poised to reenter mainstream clinical imaging with the present generations of stand-alone PET and PET/CT hybrid scanners. (18)F PET scans promise improved imaging quality for both benign and malignant bone disease, with significantly improved sensitivity and specificity over conventional planar and SPECT bone scans. In this article, basic acquisition information will be presented along with examples of studies related to oncology, sports medicine, and general orthopedics. The use of image fusion of PET bone scans with CT and MRI will be demonstrated. The objectives of this article are to provide the reader with an understanding of the history of early bone scintigraphy in relation to Na(18)F scanning, a familiarity with basic imaging techniques for PET bone scanning, an appreciation of the extent of disease processes that can be imaged with PET bone scanning, an appreciation for the added value of multimodality image fusion with bone disease, and a recognition of the potential role PET bone scanning may play in clinical imaging.

Imaging of the neonatal genito-urinary tract

Objective To describe imaging of typical conditions and diseases in the neonatal genito-urinary (GU) tract. Method The use, the applications, and typical findings using standard imaging techniques (e.g., ultrasound, US, voiding cystourethrography, VCUG) are described, with emphasis on technical aspects, indications, and restrictions in neonatal queries. Only basic applications as used in routine clinical work are included, other more sophisticated and advanced imaging techniques such as scintigraphy, MR-urography, genitography or image guided inventional procedures will only briefly be mentioned. Summary and conclusion Conventional imaging methods are valuable and – particularly in the neonatal GU tract – sometimes irreplaceable. Skilfully used basic imaging techniques, particularly of US (including modern methods such as Doppler sonography, Harmonic imaging or contrast enhanced US), supplemented by fluoroscopy for VCUG can answer most acutely treatment relevant queries. Rarely early scintigraphic studies, genitography, or MRI may become indicated, usually not for establishing the diagnosis, but to collect additional (functional or anatomical) information necessary for deciding on further treatment, or even image guided interventional procedures may become necessary.

Technical Aspects of Pediatric CMR

Cardiac magnetic resonance (CMR) of the pediatric patient involves a unique set of technical challenges above and beyond those encountered in adult imaging. Anatomical structures are smaller, demanding greater spatial resolution; heart rates are high, demanding greater temporal resolution; and patients maybe sedated or uncooperative, rendering breath-hold imaging strategies useless. Despite these difficulties, CMR offers several advantages over other imaging modalities, including soft tissue contrast, lack of ionizing radiation, a capacity for true three-dimensional imaging, accurate flow quantification, and freely selectable imaging planes. These advantages and continued advances in MR hardware, software, and imaging techniques are bringing CMR into more widespread use in pediatric cardiology. This review is a summary of the primary techniques used in pediatric CMR for both congenital and acquired cardiovascular disease. The fundamentals of CMR pulse sequences and physiological synchronization of data acquisition are described, and imaging applications are reviewed. While the basic imaging sequences and techniques are common to both pediatric and adult CMR, some significant differences in imaging priorities and strategies are discussed.

Virtual endoscopy using MRI

Driven by major improvements in high resolution MR imaging 3D reconstructions and virtual endoscopy based on MRI have become possible. This article describes basic MR imaging techniques for 3D reconstructions. Principles of MRI-based virtual endoscopy are explained. Different 3D rendering methods are mentioned and discussed. Finally, clinical applications for MRI-based virtual endoscopy are described.

Magnetic Resonance Imaging of the Fetal and Neonatal Central Nervous System

After completing this article, readers should be able to: 1. Compare and contrast magnetic resonance technology with computed tomography and ultrasonography. 2. Delineate the primary clinical uses of magnetic resonance spectroscopy, perfusion magnetic resonance, functional magnetic resonance imaging, and diffusion imaging. 3. Describe the primary uses of magnetic resonance imaging in congenital and developmental abnormalities, neurovascular disease, trauma, infections, inflammatory processes, and metabolic and neurodegenerative disorders. Magnetic resonance (MR) is one of several neuroimaging technologies used to diagnose fetal and neonatal central nervous system (CNS) abnormalities. It can aid in differentiating static from progressive encephalopathies and in diagnosing such conditions as congenital and developmental abnormalities, trauma, neurovascular disease, infections and inflammatory processes, and metabolic and neurodegenerative disorders. Although it also is helpful in diagnosing neoplastic processes, which are rare but important causes of progressive encephalopathy, these presentations are not considered in this article. MR, which employs magnetic fields and radiowaves, is a less invasive imaging technology than ultrasonography (US), computed tomography (CT), and nuclear medicine (NM), but it is more expensive. In contrast to the other modalities, which derive their signals from single parameters, the MR signal is derived exponentially from multiple parameters (eg, T1, T2, proton density, T2*, proton flow, proton relaxation enhancement, chemical shift, and molecular diffusion). MR also employs many more basic imaging techniques than other modalities, including spin echo, inversion recovery, gradient echo, and chemical shift imaging methods. Advancing MR capabilities have improved its sensitivity, specificity, and efficiency, particularly compared with US, CT, and NM. Among these advanced capabilities are the flow-attenuated inversion recovery technique (FLAIR), fat suppression short inversion time-inversion recovery imaging, and magnetization transfer imaging for increased structural resolution. Fast and ultrafast MR imaging techniques (fast spin echo, fast gradient echo, echo planar imaging) have reduced imaging times, improved structural resolution, and provided functional imaging. Specific applications …

Bone and soft tissue tumors: the role of contrast agents for MR imaging

Magnetic resonance imaging is an important modality for the imaging evaluation of musculoskeletal tumors. Although there is general agreement on the value of unenhanced MR in detection, diagnosis and staging, intravenous use of gadolinium-contrast media (gd-CM) is indicated in selected cases. The purpose of this article is to review the basic pharmacokinetic principles and imaging techniques for static and dynamic contrast-enhanced MR imaging and to highlight the most important indications for administration of gd-CM in patients with musculsokeletal tumors and tumor-like lesions: adding specificity in tissue characterization, staging of local extent and biopsy planning, monitoring preoperative chemotherapy and detection of recurrence.

Optimal target localization for ventroposterolateral pallidotomy: the role of imaging, impedance measurement, macrostimulation and microelectrode recording.

From October 1992 through December 1996, we performed 109 ventroposterolateral pallidotomies on 104 patients with Parkinson's disease. Throughout the series, we have used the basic imaging technique described by Laitinen, utilizing impedance measurement and macrostimulation to determine the optimal target position within with the pallidum and avoid the optic tract and the internal capsule. To take advantage of the high resolution of MR imaging while compensating for potential MR distortion, we have refined our stereotactic software to accomplish effective cross-registration and reformatting of CT and MR images. By 1995, several centers were suggesting that optimal target localization required microelectrode identification of pallidal neuronal firing patterns. During 1996, we performed microelectrode recording in 13 of the 25 patients undergoing pallidotomy. We have concluded that the basic technique of Laitinen, coupled with high-resolution imaging remains the foundation for achieving effective pallidotomy. Microelectrode recording is a useful adjunct to identify hyperactive firing patterns in the internal pallidum and, coupled with impedance measurements and macrostimulation, can define the lower border of the pallidum.

Periodic phenomena in Proteus mirabilis swarm colony development.

Proteus mirabilis colonies exhibit striking geometric regularity. Basic microbiological methods and imaging techniques were used to measure periodic macroscopic events in swarm colony morphogenesis. We distinguished three initial phases (lag phase, first swarming phase, and first consolidation phase) followed by repeating cycles of subsequent swarming plus consolidation phases. Each Proteus swarm colony terrace corresponds to one swarming-plus-consolidation cycle. The duration of the lag phase was dependent upon inoculation density in a way that indicated the operation of both cooperative and inhibitory multicellular effects. On our standard medium, the second and subsequent swarm phases displayed structure in the form of internal waves visible with reflected and dark-field illumination. These internal waves resulted from organization of the migrating bacteria into successively thicker cohorts of swarmer cells. Bacterial growth and motility were independently modified by altering the composition of the growth medium. By varying the glucose concentration in the substrate, it was possible to alter biomass production without greatly affecting the kinetics of colony surface area expansion. By varying the agar concentration in the substrate, initial bacterial biomass production was unaffected but colony expansion dynamics were significantly altered. Higher agar concentrations led to slower, shorter swarm phases and longer consolidation phases. Thus, colony growth was restricted by higher agar concentrations but the overall timing of the swarming-plus-consolidation cycles remained constant. None of a variety of factors which had significant effects on colony expansion altered terracing frequencies at 32 degrees C, but the length of the swarming-plus-consolidation cycle was affected by temperature and medium enrichment. Some clinical isolates displayed significant differences in terracing frequencies at 32 degrees C. Our results defined a number of readily quantifiable parameters in swarm colony development. The data showed no connection between nutrient (glucose) depletion and the onset of different phases in swarm colony morphogenesis. Several observations point to the operation of density-dependent thresholds in controlling the transitions between distinct phases.

Basic Principles of MR Contrast

The use of intravenous contrast media is well established in magnetic resonance (MR) for improved diagnosis. MR differs from other imaging modalities in the complexity of signal and contrast dependence, with the method of measurement having great impact on tissue contrast. Unlike computed tomography, in which contrast depends solely on x-ray density, the signal intensity on MR is determined by differences in spin density, T1 and T2 relaxation times, diffusion, perfusion, and magnetic susceptibility. The only contrast agents in widespread clinical use at this time are paramagnetic metal ion chelates. These compounds influence tissue contrast by enhancing T1 and T2 relaxation. The effectiveness of any one agent is dependent on a number of basic parameters, including concentration, number of coordination sites, magnetic moment, distance between the ion and water protons, and correlation times. An understanding of general contrast mechanisms, principles of contrast agent design, and basic MR imaging techniques is important for proper clinical implementation and medical diagnosis.

Reliability and Validity of Imaging Diagnosis of Temporomandibular Joint Disorder

The purpose of this article is to review reliability and validity of imaging diagnosis of temporomandibular joint disorders. Plain-film and tomography are basic imaging techniques for assessment of the temporomandibular joint. These can be used for evaluation of osseous disease and as a baseline for follow-up. In patients with symptoms from the joint, plain-film and tomography are rarely definitive, and evaluation of the soft tissues is frequently necessary. Arthrography, computed tomography, and magnetic resonance imaging have all been used for evaluation of the soft-tissue components of the joints. Accuracy studies of these techniques have demonstrated the highest diagnostic accuracy for magnetic resonance imaging. Arthrography is relatively insensitive for detection of medial and lateral displacements. Magnetic resonance imaging accurately depicts both hard and soft tissues, and this technique is emerging as the prime diagnostic imaging technique in patients presenting with clinical signs and symptoms of a disorder of the temporomandibular joint. The most frequent findings when patients with clinical symptoms of temporomandibular joint disorders are "imaged" are different forms of disc displacement and degenerative joint disease. Studies have demonstrated a high prevalence of different forms of disc displacement in patients, although these abnormalities are also seen in some asymptomatic volunteers. Future research should further refine imaging techniques to come closer to an understanding of the association between morphologic alterations and patient symptoms.

Basic cardiovascular magnetic resonance imaging techniques

Basic cardiovascular magnetic resonance imaging techniques