Topics in magnetic resonance imaging: TMRI

Publications in this journal

• Article: Magnetic resonance-guided interventions of large and small joints.

  Marietta Garmer, Dietrich Grönemeyer
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  ABSTRACT: Magnetic resonance (MR)-guided interventions of large and small joints are feasible and safe procedures offering several advantages compared with standard guiding techniques. Nevertheless, MR-guided interventions are not routinely performed in daily practice apart from a few centers. Accurate injections are crucial for clinical outcome in diagnostic arthrography as well as therapeutic joint injections. In particular, palpatory joint puncture was shown to be inaccurate or uncertain in a substantial percentage of injections of the shoulder, the hip, and the knee. Magnetic resonance imaging offers respective merits of a cross-sectional technique with high soft-tissue contrast. Exact depiction of structures, which should be preserved, such as the labrum, should be aimed for. Areas with complex anatomy can be approached by adapting the right imaging plane(s) because of multiplanar capacity. Lack of ionizing radiation for patients is of growing interest particularly in young patients with repeated interventions. Magnetic resonance guidance alone allows an "all-in-one" MR arthrography combining precise targeting with high-field-strength imaging. Modern short-bore and open-bore high-field-strength systems offer a good comfort for patients as well as clinicians and enhance patient positioning options such as supine or prone position. Thus, a tailored approach such as a posterior technique for suspected anterior lesions in shoulder MR arthrography is possible.In this article, we describe the advantages and limitations of MR guidance in joint interventions with focus on shoulder and hip interventions. We review the requirements for needle material and MR sequences, discuss several different techniques developed to date, and present current results in clinical outcome.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):153-69.
• Article: Percutaneous magnetic resonance imaging-guided bone tumor management and magnetic resonance imaging-guided bone therapy.

  Roberto Blanco Sequeiros, Jan Fritz, Risto Ojala, John A Carrino
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  ABSTRACT: Magnetic resonance imaging (MRI) is promising tool for image-guided therapy. In musculoskeletal setting, image-guided therapy is used to direct diagnostic and therapeutic procedures and to steer patient management. Studies have demonstrated that MRI-guided interventions involving bone, soft tissue, joints, and intervertebral disks are safe and in selected indications can be the preferred action to manage clinical situation. Often, these procedures are technically similar to those performed in other modalities (computed tomography, fluoroscopy) for bone and soft tissue lesions. However, the procedural perception to the operator can be very different to other modalities because of the vastly increased data.Magnetic resonance imaging guidance is particularly advantageous should the lesion not be visible by other modalities, for selective lesion targeting, intra-articular locations, cyst aspiration, and locations adjacent to surgical hardware. Palliative tumor-related pain management such as ablation therapy forms a subset of procedures that are frequently performed under MRI. Another suitable entity for MRI guidance are the therapeutic percutaneous osseous or joint-related benign or reactive conditions such as osteoid osteoma, epiphyseal bone bridging, osteochondritis dissecans, bone cysts, localized bone necrosis, and posttraumatic lesions. In this article, we will describe in detail the technical aspects of performing MRI-guided therapeutic musculoskeletal procedures as well as the clinical indications.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):171-7.
• Article: Magnetic resonance imaging-guided spine injections.

  Jan Fritz, Roberto Blanco Sequeiros, John A Carrino
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  ABSTRACT: Magnetic resonance (MR)-guided spine injections describe techniques for selective spine injection procedures, in which MR imaging is used to visualize spinal targets and needle placement, monitor the injected drugs, and detect spread to potentially confounding nearby structures. The introduction of clinical high-field wide-bore MR imaging systems has increased the practicability and availability of MR-guided spine injections. The use of 1.5-T field strength, modern coils, and parallel imaging technology increases the MR signal, which can be utilized for faster temporal image acquisition, higher image resolution, better image contrast, or combinations thereof. Magnetic resonance imaging guidance provides excellent osseous and soft-tissue detail of spinal structures and is well suited to avoid radiation exposure. In this article, we discuss the technical background of interventional MR imaging, review the literature, and illustrate interventional MR imaging techniques of commonly performed spinal injection procedures, including sacroiliac joint injections, lumbar facet joint injections, selective spinal nerve root infiltration, and percutaneous drug delivery to the lumbar sympathetic nerves.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):143-51.
• Article: Magnetic resonance imaging-guided biopsy of musculoskeletal lesions using open low-field systems.

  Chengli Li, Yubo Lü, Ming Liu, Jan Fritz
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  ABSTRACT: With the development of open-configuration magnetic resonance imaging (MRI) systems, magnetic resonance-compatible navigational tools, and fast pulse sequences, MRI-guided biopsy of musculoskeletal lesions has evolved into an effective and safe, minimally invasive technique. Magnetic resonance-guided percutaneous biopsy of musculoskeletal lesions is especially suited for lesions that are detectable only with MRI, lesions that require double-angulated needle paths, and for patients in which radiation exposure needs to be avoided. In this article, we review pertinent principles, techniques, and clinical applications of low-field MRI for biopsy procedures in the musculoskeletal system.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):135-41.
• Article: MRI-Guided Musculoskeletal Soft Tissue Interventions.

  Sherif G Nour, David K Monson
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  ABSTRACT: This article highlights some of current state-of-the-art applications of interventional magnetic resonance imaging (MRI) technology pertaining to the musculoskeletal soft tissues. The rationale for the use of these techniques is to provide modes of minimally invasive diagnosis and/or therapy for a subset of patients whose lesions are not approachable by the traditional modes of interventional radiology and to introduce methods to mark subtle and infiltrative lesions to improve the outcomes of subsequent surgery or radiation therapy. These techniques build on the inherent attributes of MRI, particularly the high soft tissue contrast that made MRI the current mainstay diagnostic modality to identify and characterize musculoskeletal soft tissue lesions. The application of MRI technology to the musculoskeletal system, particularly for lesions related to the appendicular skeleton, does not typically suffer from the complexity related to involuntary organ motion. In addition, MRI-compatible versions of most of the needed instruments and devices for these interventions are currently available on commercial basis. Although musculoskeletal applications were not adopted early during the development of interventional MRI technology, we are likely to observe an increasing use of this technology for musculoskeletal soft tissue applications in the future.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):197-205.
• Article: Magnetic resonance imaging in interventional musculoskeletal disease.

  John A Carrino, Jan Fritz
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):133.
• Article: Navigation concepts for magnetic resonance imaging-guided musculoskeletal interventions.

  Harald Busse, Thomas Kahn, Michael Moche
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  ABSTRACT: Image-guided musculoskeletal (MSK) interventions are a widely used alternative to open surgical procedures for various pathological findings in different body regions. They traditionally involve one of the established x-ray imaging techniques (radiography, fluoroscopy, computed tomography) or ultrasound scanning. Over the last decades, magnetic resonance imaging (MRI) has evolved into one of the most powerful diagnostic tools for nearly the whole body and has therefore been increasingly considered for interventional guidance as well.The strength of MRI for MSK applications is a combination of well-known general advantages, such as multiplanar and functional imaging capabilities, wide choice of tissue contrasts, and absence of ionizing radiation, as well as a number of MSK-specific factors, for example, the excellent depiction of soft-tissue tumors, nonosteolytic bone changes, and bone marrow lesions. On the downside, the magnetic resonance-compatible equipment needed, restricted space in the magnet, longer imaging times, and the more complex workflow have so far limited the number of MSK procedures under MRI guidance.Navigation solutions are generally a natural extension of any interventional imaging system, in particular, because powerful hardware and software for image processing have become routinely available. They help to identify proper access paths, provide accurate feedback on the instrument positions, facilitate the workflow in an MRI environment, and ultimately contribute to procedural safety and success.The purposes of this work were to describe some basic concepts and devices for MRI guidance of MSK procedures and to discuss technical and clinical achievements and challenges for some selected implementations.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):179-88.
• Article: Magnetic resonance imaging-guided biopsy in the musculoskeletal system using a cylindrical 1.5-T magnetic resonance imaging unit.

  Judy U Ahrar, R Jason Stafford, Sadeer Alzubaidi, Kamran Ahrar
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  ABSTRACT: The objective of this study was to report a single-center experience with magnetic resonance imaging (MRI)-guided biopsy in the musculoskeletal system using a closed-bore, cylindrical, high-magnetic-field (1.5-T) MRI unit. From May 2010 to July 2011, 100 consecutive MRI-guided biopsy sessions were undertaken for musculoskeletal lesions in 97 patients. Patient demographics, tumor characteristics, and biopsy techniques were recorded. Biopsy results, treatment outcomes, and follow-up imaging studies were reviewed. Biopsy procedures were technically successful in 99 cases (99%). Despite a mean body mass index of 30 kg/m, all patients fit within the bore of the magnet. There were 69 soft-tissue and 31 bone tumors. Most patients had both tissue core (n = 93) and fine-needle aspiration (n = 84) biopsies. All lesions were adequately imaged, localized, and targeted using rapid balanced steady-state free precession imaging (89%), fast T1 (4%), or combination of the 2 techniques (7%). A prototype real-time imaging sequence was used in 29 cases (29%) to guide biopsy needle insertion. There were no major complications. Sensitivity, specificity, and overall accuracy were 97%, 100%, and 97.6%, respectively. Magnetic resonance imaging-guided biopsy in a closed-bore, high-field-strength magnet is a safe, easy, and effective technique for evaluation of musculoskeletal lesions. Ideally, the MRI suite should be equipped with an in-room radiofrequency-shielded monitor and a communication system. However, surface coils with adequate opening to grant access to the biopsy site, MRI-compatible needles, and MRI-compatible patient monitoring devices are absolutely necessary to perform MRI-guided biopsies.
  Topics in magnetic resonance imaging: TMRI 08/2011; 22(4):189-96.
• Article: Fetal MRI: The Sonographer's View.

  Denise Pugash
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  ABSTRACT: Fetal magnetic resonance imaging (MRI) is used with increasing frequency as a complementary imaging modality to ultrasound (US) in prenatal diagnosis. Fetal MRI displays the fetal, uterine, and extrauterine anatomy in ways that allow confirmation of normal anatomy and the diagnosis of pathological entities that were formerly very difficult to detect prenatally. Comparison of US views with standard orthogonal plane MR images reinforces the understanding of fetal anatomy as visualized with US. Technological advances in US equipment have allowed the recent description of subtle fetal anatomical structures. Similarly, knowledge of the MRI appearances of pathological conditions has opened opportunities for the sonographic diagnosis of entities such as brainstem malformations and alterations in the normal transient laminar pattern that occur during development of the fetal cerebrum. Fetal MRI can confirm suspicious US findings and thus add confidence in a particular prenatal diagnosis before performing invasive and interventional procedures. Specific MRI sequences can be used to add information about the chemical composition of fetal structures, such as fat, blood, and meconium. Dynamic MRI sequences have increased understanding of gestational age-dependent behavior, and assist the sonographer in assessment of fetal structural anomalies that cause abnormal movement and behavior. The technological ability of US to demonstrate very small structures complements the lower resolution of fetal MR images, whereas the ability of MR to visualize the whole fetus improves the limited views necessitated by US. Therefore, both US and fetal MRI have complementary strengths and weaknesses that can be used to full advantage in prenatal diagnosis.
  Topics in magnetic resonance imaging: TMRI 06/2011; 22(3):91-9.
• Article: Fetal magnetic resonance imaging at 3.0 T.

  Robert C Welsh, Ursula Nemec, Moriah E Thomason
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  ABSTRACT: Magnetic resonance imaging (MRI) has been used to image the in utero fetus for the past 3 decades. Although not as commonplace as other patient-oriented MRI, it is a growing field and demonstrating a role in the clinical care of the fetus. Indeed, the body of literature involving fetal MRI exceeds 3000 published articles. Indeed, there is interest in accessing even the healthy fetus with MRI to further understand the development of humans during the fetal stage. On the horizon is fetal imaging using 3.0-T clinical systems. Although a clear path is not necessarily determined, experiments, theoretical calculations, advances in pulse sequence design, new hardware, and experience from imaging at 1.5 T help define the path.
  Topics in magnetic resonance imaging: TMRI 06/2011; 22(3):119-31.
• Article: Atlas learning in fetal brain development.

  Eva Dittrich, Gregor Kasprian, Daniela Prayer, Georg Langs
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  ABSTRACT: Magnetic resonance imaging has become an important noninvasive technique to gain insight into fetal brain development. Its capabilities go beyond ultrasound when diagnosing high-risk pregnancies. To summarize observations across a population in magnetic resonance imaging studies, reference systems such as atlases that establish correspondences across a cohort are key. In this article, we review the evolution of atlas-building methods in light of their relevance, limitations, and benefits for the modeling of human brain development. Starting with single anatomical templates to which brain scans where mapped to such as Talairach and Montreal Neurological Institute space, we explore the uses of atlases as a means to establish correspondences across a cohort and as a model that captures the population characteristics of the cases the atlas is built from. We discuss methods that capture features of increasingly heterogeneous populations and approaches that are able to generalize with only minimal annotation. The main focus of this review are methods that explicitly model the variability in the population with regard to time, such as in the modeling of disease progression and brain development. We highlight the applicability and limitations of state-of-the art approaches, how insights from the study of disease progression are helpful in developmental studies, and point to the directions of future research that is still necessary.
  Topics in magnetic resonance imaging: TMRI 06/2011; 22(3):107-11.
• Article: Skeletal development on fetal magnetic resonance imaging.

  Stefan Franz Nemec, Ursula Nemec, Peter C Brugger, Isha Wadhawan, Daniela Prayer
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  ABSTRACT: Prenatal magnetic resonance imaging (MRI) is being increasingly used, in addition to standard ultrasound, for the diagnosis of congenital diseases beyond the central nervous system. Previous studies have demonstrated that MRI may be useful for the in utero visualization of spinal dysraphism and for differentiating between isolated and complex skeletal disorders with associated abnormalities. More recently, attention has focused on the visualization of the human fetal skeleton for the delineation of normal and pathological development of skeletal structures. On 1.5 T, in particular, echoplanar imaging enables the delineation of various epimetaphyseal structures and morphometric measurements of the fetal long bones from 18 gestational weeks until term. This information gathered from prenatal MRI might be helpful in the diagnosis of focal bone abnormalities and generalized skeletal disorders, such as bone dysplasias. Further clinical research, along with the refinement of the newest techniques, will enable expansion of the preliminary findings and help in determining the impact of fetal magnetic resonance bone imaging in the routine clinical setting. This review summarizes the current data in the literature and the authors' clinical experience with the magnetic resonance visualization of the developing fetal skeleton and also comments on the potential future applications of this technique.
  Topics in magnetic resonance imaging: TMRI 06/2011; 22(3):101-6.
• Article: Fetal MRI.

  Daniela Prayer
  Topics in magnetic resonance imaging: TMRI 06/2011; 22(3):89.
• Article: Molecular characterization of rheumatoid arthritis with magnetic resonance imaging.

  Jeffrey T Gu, Linda Nguyen, Abhijit J Chaudhari, John D MacKenzie
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  ABSTRACT: Several recent advances in the field of magnetic resonance imaging (MRI) may transform the detection and monitoring of rheumatoid arthritis (RA). These advances depict both anatomic and molecular alterations from RA. Previous techniques could detect specific end products of metabolism in vitro or were limited to providing anatomic information. This review focuses on the novel molecular imaging techniques of hyperpolarized carbon-13 MRI, MRI with iron-labeled probes, and fusion of MRI with positron emission tomography. These new imaging approaches go beyond the anatomic description of RA and lend new information into the status of this disease by giving molecular information.
  Topics in magnetic resonance imaging: TMRI 04/2011; 22(2):61-9.
• Article: Magnetic resonance imaging of inflammatory arthropathies of peripheral joints.

  Michael C Forney, Carl S Winalski, Jean P Schils
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  ABSTRACT: As the treatment of inflammatory arthropathies has advanced with new therapies that can slow or even halt the development of disabling disease, early and accurate diagnosis has become imperative. Magnetic resonance (MR) imaging has proved to be very sensitive in the detection of erosions, but more importantly, it can demonstrate pre-erosive changes. Detection of synovitis and edema-like bone marrow lesions for initial diagnosis and as an indicator of disease progression can provide crucial information leading to therapeutic interventions before permanent joint damage occurs. Understanding the characteristic intra-articular and extra-articular MR imaging findings of the inflammatory arthritides allows the radiologist to provide appropriate consultations in the care of these patients. The MR appearances of both intra-articular and extra-articular findings of inflammatory arthritis are presented. Despite the advances in imaging, however, many of the MR findings remain nonspecific, and radiologists must avoid overdiagnosis by synthesizing all of the clinical information available into their interpretations.
  Topics in magnetic resonance imaging: TMRI 04/2011; 22(2):45-59.
• Article: Magnetic resonance imaging of spondyloarthritis: spine and SI joints.

  Filippo Del Grande, John A Carrino, Marco Zanetti
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  ABSTRACT: Magnetic resonance imaging (MRI) has been recently introduced as a classification criterion for spondyloarthropathies in the Assessment of Spondylarthritis International Society criteria. Therefore, it plays an increasingly important role in the diagnostic workup of spondyloarthropathies. In this article, we will review the MRI imaging features of axial spondyloarthritis from sacroiliitis to spine abnormalities; we will explain the rationale for MRI imaging, the evidence for whole body MRI, and we will approach the use of MRI for monitoring treatment response.
  Topics in magnetic resonance imaging: TMRI 04/2011; 22(2):83-8.
• Article: Magnetic resonance imaging of inflammatory myopathies.

  Filippo Del Grande, John A Carrino, Maria Del Grande, Andrew L Mammen, Lisa Christopher Stine
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  ABSTRACT: The following article reviews the role of magnetic resonance imaging (MRI) in patients with idiopathic inflammatory myopathies (IIMs), focusing on the 3 major types of IIM: polymyositis, dermatomyositis, and inclusion-body myositis. After a brief introduction with general information about IIM, we will discuss the reasons why MRI plays an important role in the diagnosis and management of patients with polymyositis, dermatomyositis, and inclusion-body myositis. Magnetic resonance imaging can confirm the diagnosis and can help to phenotype the disease. Moreover, the support of MRI is important in addressing the muscle biopsy site and in reducing the high false-negative rate of biopsy when performed in a blind fashion. In monitoring therapy, MRI can add important information about the activity of the muscle disease and can identify cases where continued immunosuppressive therapy is no longer warranted owing to complete fatty replacement of the muscles. Lastly, we provide an overview about some advanced MRI techniques that focus more on function than on morphology of muscle.
  Topics in magnetic resonance imaging: TMRI 04/2011; 22(2):39-43.
• Article: Cartilage magnetic resonance imaging techniques at 3 T: current status and future directions.

  Rashmi S Thakkar, Ty Subhawong, John A Carrino, Avneesh Chhabra
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  ABSTRACT: Magnetic resonance imaging (MRI) remains the imaging modality of choice for morphological and compositional evaluation of the articular cartilage. Accurate detection and characterization of cartilage lesions are necessary to guide the medical and surgical therapy and are also critical for longitudinal studies of the cartilage. Recent work using 3.0-T MRI systems shows promise in improving detection and characterization of the cartilage lesions, particularly with increasing use of high-resolution and high-contrast 3-dimensional sequences, which allow detailed morphological assessment of cartilage in arbitrary imaging planes. In addition, implementation of biochemical sequences in clinically feasible scan times has a potential in the early detection of cartilage lesions before they become morphologically apparent. This article discusses relative advantages and disadvantages of various commonly used as well as experimental MRI techniques to directly assess the morphology and indirectly evaluate the biochemical composition of the articular cartilage.
  Topics in magnetic resonance imaging: TMRI 04/2011; 22(2):71-81.
• Article: Contributions of diffusion-weighted imaging to fetal and neonatal imaging.

  Orit Glenn
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  ABSTRACT: Diffusion-weighted imaging has contributed to our understanding of fetal and neonatal brain development. This article will review the role of diffusion-weighted imaging and diffusion tensor imaging in fetuses and neonates, focusing primarily on normal brain developmental processes and then on pathologic processes that can be characterized using diffusion tensor imaging.
  Topics in magnetic resonance imaging: TMRI 02/2011; 22(1):3-9.