The vascular patient--diagnosis and minimally invasive therapy. Which technique for what illness?

The non-invasive imaging modalities, color coded duplex sonography (CCDS), magnetic resonance tomography (MRT), and computed tomography (CT), have pushed conventional angiography out of most diagnostic fields. The experienced user will achieve fast, reliable answers with CCDS in dedicated clinical settings. MRT as well as CT are concurring imaging modalities for the most appropriate diagnostic answer. Not only pure image quality, but also patient management, and availability play a major role. Catheter based angiography will in the future still play a role in mesenteric ischemia (non occlusive disease) and for imaging of very small vessel pathology, e.g. on panarteritis nodosa. At the moment, peripheral leg run-offs are still best performed with conventional angiography, nevertheless, MR as well as CT seem to have the ability to perform diagnostic procedures. Ongoing studies will allow a solid judgement in the near future. The true value of catheter angiography is in the direct assessment, planning, and performance of interventional procedures, e.g. catheter based obliteration or revascularization. Implantation of stent devices and a whole range of different mechanical and pharmacological revascularization procedures have improved the interventional management of vascular stenoses and occlusions. The interventional radiologist is treating physician in the classical sense in this setting. Acute bleeding episodes, e.g. in the brain, thorax, abdomen, or pelvis, are best imaged with computed tomography. Conventional angiography still plays a major diagnostic and therapeutic role in bleeding into preformed cavities, such as the bile ducts or the intestine. In this setting, all available information including CT scans should be valued. For complex therapeutic regimens in oncology or in pure palliative situations, angiographic diagnosis followed by embolization and/or ablation therapy is established.     

Nuclear medicine at a crossroads

The growth of molecular imaging heightens the promise of clinical nuclear medicine as a tool for individualization of patient care and for improvement of health-care outcomes. Together with greater use of integrated structure-function imaging, clinical nuclear medicine reaches beyond traditional specialty borders into diagnostic radiology and oncology. Yet, there are concerns about the future of nuclear medicine, including progressively declining reimbursement, the competitive advantages of diagnostic radiology, limited translation of research accomplishments to clinical diagnostic imaging and patient care, and an insufficient pool of incoming highly qualified nuclear medicine clinicians. Thus, nuclear medicine views itself as being at a critical crossroads. What will be important is for nuclear medicine to be positioned as the quintessential molecular imaging modality more centrally within medical imaging and for the integration of nuclear medicine with primary care specialties to be driven more by patient needs than by specialty needs. In this way, the full potential of nuclear medicine as an effective and efficient tool for improving patient outcomes can be realized.     

Non-traumatic vascular emergencies: imaging and intervention in acute arterial conditions

Methods of imaging and intervention in acute non-traumatic vascular arterial conditions has changed substantially during recent years. Computed tomography, MRI angiography and, more recently, intravascular ultrasonography (IVUS) have replaced to a large extent conventional diagnostic angiography. An increasing number of patients are treated by endovascular interventions and numerous new treatment methods have been evaluated. Technical development of new equipment and instruments, increasing skill of interventional radiologists and better understanding of events following interventions improve continuously results of the treatment. Radiologic diagnosis and intervention have important roles in the treatment of acute non-traumatic vascular arterial conditions. Electronic Publication     

加强介入治疗围手术期处理能力

介入放射学是一门新兴学科,从事这一学科的医师应该具有扎实的影像学基础、娴熟的操作技能和丰富的临床经验.这三方面足每一位从事介入放射诊疗的医师都必须为此而努力的.许多从影像诊断转做介入治疗的医师,他们有扎实的影像学知识,也努力学习介入诊疗操作,但是往往缺乏临床知识,对介入围手术期的处理缺乏相应的临床经验.而介入围手术期是介入治疗的重要组成部分,规范的介入治疗的术前准备能有效减少术后并发症,科学的术后处理能使患者获得最佳的手术效果.     

Diuretic renography and angiotensin converting enzyme inhibitor renography

Renovascular hypertension and renal outlet obstruction are two clinical conditions well evaluated by nuclear medicine techniques. They both require a specific intervention to challenge a specific aspect of renal functional reserve. Diuretic renography is the oldest common example in nuclear medicine where functional change in the kidney is provoked for diagnostic purposes. The kidney's tubular functional reserve, in this instance, is challenged to induce diuresis and increase urine flow. This intervention permits diuretic renography to retain an essential role in the evaluation of hydroureteronephrosis. Captopril renography is a more recent example of a similar principle and depends on a reactive renin-angiotensin system to identify a kidney responsible for RVH. In both renal outlet obstruction and RVH, an anatomic abnormality is also identified (hydronephrosis and RAS, respectively) at some point in the diagnostic workup. The final diagnosis in each instance, however, depends on evidence for a functional disorder, provoked and measured during the radionuclide interventional examination. These serve as excellent examples of the power of functional imaging to identify specific medical disorders.     

Molecular imaging: an overview and clinical applications

Molecular imaging is a new medical discipline that integrates cell biology, molecular biology and diagnostic imaging. Clinical applications of molecular imaging include the use of nuclear medicine, magnetic resonance imaging (MRI) and ultrasound (US). The nuclear medicine applications utilize devices such as single photon emission computerized tomography (SPECT) and positron emission tomography (PET). Molecular imaging has two basic applications. The first is diagnostic imaging, which is used to determine the location and extent of targeted molecules specific to the disease being assessed. The second is therapy, which is used to treat specific disease-targeted molecules. The basic principle of the diagnostic imaging application is derived from the ability of cell and molecular biologists to identify specific receptor sites associated with target molecules that characterize the disease process to be studied. The biology teams then develop molecular imaging agents, which will bind specifically to the target molecules of interest. The principle for using molecular targeting therapy is based on an extension of the diagnostic imaging principle. Basically, it is assumed that if the molecular probe does target the specific disease molecules of interest, the same molecular agent can be loaded with an agent that will deliver therapy to the targeted cells. Patients and physicians have the clinical expectation that molecular imaging, when used for diagnostic purposes, will significantly improve the time-liness as well as the accuracy of detecting the presence and extent of disease. When applied to therapy, the expectation is that FDA-approved agents will have been shown in clinical trials to provide a significant improvement in clinical outcomes over traditional therapy methods. The eventual clinical owners of molecular imaging may be a specialty group that is a hybrid by conventional measures. For example, the clinical owner should have fundamental knowledge in basic cellular and molecular biology but must also be certified as well as competent in the specific diagnostic imaging specialty applied (i.e. nuclear, MR or ultrasound). If the owner is also to be involved with therapy, experience and appropriate certification will also be required. Another issue relates specifically to the therapy applications in oncology. It is conceivable that traditional chemotherapy and radiotherapy may be replaced in part with molecular imaging therapy that utilizes target-specific agents to treat cancer on a non-toxic, outpatient basis. The issue to be addressed by the radiology administrator is whether this new discipline will be performed in the radiology department or oncology and radiotherapy departments. Clearly, radiology and its associated diagnostic imaging subspecialties are the most logical owner of molecular imaging. However, to make this ownership a reality will require major shifts in training requirements, as well as exertion of political influence from the radiology administrators against other specialties that have much to lose in terms of patient populations and revenue to their practice.     

Economic challenges in breast imaging. A survivor's guide to success

Most breast imaging centers today operate under financial strain. Among strategies designed to improve their bottom line, more efficient use of the radiologist's time is the most fundamental strategy and the one most likely to succeed in all breast imaging centers. Tasks performed by the radiologist that are not directly related to interpretation and consultation should be shifted to other personnel. Other strategies that may help some breast imaging centers include accepting only self-paying patients, renegotiating the hospital contract, performing more interventional procedures, and extending the hours of operation. Measures that can improve the economic efficiency of screening mammography include batch interpretation of mammograms; paperwork reduction; brief automated reports; limiting requests for previous films from other facilities to only potentially necessary cases; dedicated screening mammography examination rooms; reduction in recall rates; and, in certain circumstances, extension of breast center hours. Measures that can improve the economic efficiency of diagnostic mammography performance and interpretation include dedicated diagnostic mammography examination rooms, automated film rotators, improved scheduling, and efficient work-flow patterns for examination performance. Measures that can improve the economic efficiency of both screening and diagnostic mammography include improved triage of screening and diagnostic patients, reminder telephone calls to confirm mammography appointments, greater use of medical assistants to help the radiologists and technologists, and streamlined film library procedures and operations. Measures that can improve the economic efficiency of breast interventional procedures include preprocedure work-up, establishment of scheduling protocols, and greater involvement of technologists and medical assistants in assisting the radiologist who performs the interventional procedures. All of these methods are intended to create a breast imaging center that is cost efficient while maintaining a patient-friendly atmosphere and diagnostic accuracy.     

心血管病介入操作时患者受照剂量估算

放射诊疗新技术给人类带来了巨大的利益,放射性介入操作是其中最具代表性的一类新技术.然而在放射性介入操作的过程中,患者受照剂量在医用X射线诊断和治疗中是最高的,其剂量可能大到能引起皮肤和眼晶体辐射损伤,而且其防护也是目前职业辐射防护中最困难的.目前有60%左右的介入术是在心血管病的治疗中开展,心血管病介入操作时患者的辐射防护问题已引起了国内外广泛的重视,并开展了较为广泛的研究.大量的研究结果表明,心血管病放射性介入操作可能给患者造成值得重视的高剂量辐射.但是许多研究都是集中在表面剂量,这个量对评估患者的风险是远远不够的.在外照射情况下,当人体受穿透力强的辐射(X射线、γ射线、中子)照射一定剂量时,可造成深部组织和器官损伤,因此在研究表面剂量的同时,研究深部组织和器官的剂量也是至关重要的.由于放射性介入操作可能引起肿瘤和遗传这类随机性效应损伤,因此需要估算其有效剂量.     

Inferior epigastric artery injury after percutaneous imaging-guided peritoneal dialysis catheter placement

Inferior epigastric artery (IEA) injury is a rare clinical entity that is usually associated with abdominal wall procedures and injuries though can also be spontaneous, particularly in individuals with coagulopathy. Of all described mechanisms of injury, percutaneous peritoneal dialysis (PD) catheter insertion is a rarely encountered, particularly in instances where insertion is performed under imaging guidance. While this injury is self-limited, it can be associated with hemodynamic instability and acute blood loss anemia, which can be fatal if left untreated. Computed tomographic (CT) angiography is the diagnostic method of choice. Transcatheter arterial embolization is an effective treatment modality with a high success rate. Here, we describe a 41-year-old female who underwent percutaneous PD catheter insertion that, despite intraprocedural imaging guidance, was complicated by large hemoperitoneum and clinical instability. Prompt identification of IEA injury followed by immediate intervention with coil embolization led to a successful outcome for this patient in the setting of a life-threatening uncommon complication of such procedure. The details of the diagnostic evaluation and management are outlined.     

Technical cost of radiologic examinations: analysis across imaging modalities

PURPOSE: To determine the individual technical costs of general diagnostic radiographic, ultrasonographic (US), computed tomographic (CT), magnetic resonance (MR) imaging, and scintigraphic examinations and interventional radiology. MATERIALS AND METHODS: The Radiology Cost and Productivity Benchmarking Study method of the University HealthSystem Consortium, a cooperative group of academic medical centers, was modified and extended to the six imaging modalities in a tertiary care academic setting. Hospital billing and cost records were analyzed for fiscal year 1996. Costs were divided into labor and nonlabor categories and were allocated to individual imaging modalities on the basis of resources consumed. Physician cost and hospital overhead were not included. Unit costs were analyzed per technical relative value unit (RVU) and per examination. RESULTS: The costs per technical RVU for diagnostic radiography, US, CT, MR imaging, scintigraphy, and interventional radiology were $65. 06, $28.74, $20.95, $17.69, $42.19, and $89.03, respectively. The technical costs per examination for diagnostic radiography, US, CT, MR imaging, scintigraphy, and interventional radiology were $41.92, $50.28, $112.32, $266.96, $196.88, and $692.60, respectively. CONCLUSION: The method of unit cost analysis for individual imaging modalities was successfully tested in a tertiary care setting. The method should be adopted to allow cost comparison across many institutions, which will permit the promotion of best practices.     

Interventional and intraoperative MR: review and update of techniques and clinical experience

The concept of interventional magnetic resonance imaging (MRI) is based on the integration of diagnostic and therapeutic procedures, favored by the combination of the excellent morphological and functional imaging characteristics of MRI. The spectrum of MRI-assisted interventions ranges from biopsies and intraoperative guidance to thermal ablation modalities and vascular interventions. The most relevant recently published experimental and clinical results are discussed. In the future, interventional MRI is expected to play an important role in interventional radiology, minimal invasive therapy and guidance of surgical procedures. However, the associated high costs require a careful evaluation of its potentials in order to ensure cost-effective medical care.     

Accuracy of semi-automated versus manual localisation of liver tumours in CT-guided ablation procedures

Objectives

To compare the accuracy of liver tumour localisation in intraprocedural computed tomography (CT) images of computer-based rigid registration or non-rigid registration versus mental registration performed by interventional radiologists.

Methods

Retrospectively (2009-2017), 35 contrast-enhanced CT (CECT) images incorporating 56 tumours, acquired during CT-guided ablation procedures and their corresponding pre-procedural diagnostic CECTs were retrieved from the picture archiving and communication system (PACS). The original intraprocedural CECTs were de-enhanced to create a virtually unenhanced CT image (VUCT). Alignment of diagnostic CECTs to their corresponding intraprocedural VUCTs was performed with non-rigid or rigid registration. Mental registration was performed by four interventional radiologists. The original intraprocedural CECT served as the reference standard. Accuracy of tumour localisation was assessed with the target registration error (TRE). Statistical differences were analysed with the Wilcoxon signed-rank test.

Results

Non-rigid registration failed to register two CT datasets, incorporating four tumours. In the remaining 33 datasets, non-rigid, rigid and mental registration showed a median TRE of 3.9 mm, 9.0 mm and 10.9 mm, respectively. Non-rigid registration was significantly more accurate in tumour centre localisation in comparison to rigid (p < 0.001) or mental registration (p < 0.001). Rigid registration was not statistically different from mental registration (p = 0.169). Non-rigid registration was most accurate in localising tumour centres in 42 out of 52 tumours (80.8%), while rigid and mental registration were most accurate in only seven (13.5%) and three (5.8%) tumours, respectively.

Conclusions

Computer-based non-rigid registration is statistically significantly more accurate in localising liver tumours in intraprocedural unenhanced CT images in comparison to rigid registration or interventional radiologists’ mental mapping abilities.

Key Points

? Computer-based non-rigid registration is better (p < 0.001) in localising target tumours prior to ablation in intraprocedural CT images in comparison to rigid registration or interventional radiologists’ mental mapping abilities. ? Human experts perform sub-optimal localisation of target tumours when relying solely on mental mapping during challenging CT-guided procedures. ? This non-rigid registration method shows promising results as a safe alternative to intravenous contrast media in liver tumour localisation prior to ablation during CT-guided procedures.

     

MR systems for MRI-guided interventions

The field of MR imaging has grown from diagnosis via morphologic imaging to more sophisticated diagnosis via both physiologic and morphologic imaging and finally to the guidance and control of interventions. A wide variety of interventional procedures from open brain surgeries to noninvasive focused ultrasound ablations have been guided with MR and the differences between diagnostic and interventional MR imaging systems have motivated the creation of a new field within MR. This review discusses the various systems that research groups and vendors have designed to meet the requirements of interventional MR and suggest possible solutions to those requirements that have not yet been met. The common requirements created by MR imaging guidance of interventional procedures are reviewed and different imaging system designs will be independently considered. The motivation and history of the different designs are discussed and the ability of the designs to satisfy the requirements is analyzed.     

Evidence-based Practice in Radiology: steps 3 and 4--appraise and apply interventional radiology literature

When introducing new interventional radiology techniques or devices, it is important to learn from previous experiences and to remember that there are numerous examples of new techniques that were initially enthusiastically promoted and then subsequently abandoned when early promise was not realized. Appropriateness of new or established interventional radiology techniques to specific clinical conditions must be determined from clinical experience, from communication with experts in the field and/or careful review of available medical literature, and on an individual patient basis by means of review of clinical notes and diagnostic imaging studies. Several paradigms for evidence-based practice (EBP) exist. One model proposes that a central specialized process involving academic centers should primarily construct valid guidelines to direct practice at all levels of medical practice ("top-down" model). An alternative model integrates "the best research evidence with clinical expertise and patient values" ("bottom-up" model). This article will focus on the bottom-up model and describe the use of EBP by individual practitioners or groups of practitioners in optimizing literature review and critical appraisal. EBP is applied to two scenarios as a means of deciding the appropriateness of introducing interventional radiology techniques in a community hospital setting. The authors will also briefly discuss other applications for EBP techniques in interventional radiology, including development of practice guidelines or policy to ensure appropriate and safe practices.     

Vascular Complications of Pancreatitis: Imaging and Intervention

The objective of this study was to highlight technical challenges and potential pitfalls of diagnostic imaging, intervention, and postintervention follow-up of vascular complications of pancreatitis. Diagnostic and interventional radiology imaging from patients with pancreatitis from 2002 to 2006 was reviewed. We conclude that biphasic CT is the diagnostic modality of choice. Catheter angiography may (still) be required to diagnose small pseudoaneurysms. Endovascular coiling is the treatment of choice for pseudoaneurysms. Close clinical follow-up is required, as patients may rebleed/develop aneurysms elsewhere.     

Intravascular ultrasound imaging of peripheral arteries as an adjunct to balloon angioplasty and atherectomy

This article reviews many of the applications of intravascular ultrasound (US) imaging for peripheral arterial diseases. In vitro studies demonstrate an excellent correlation between ultrasound measurements of lumen and plaque crossectional area compared with histologic sections. In vivo clinical studies reveal the enhanced diagnostic capabilities of this technology compared with angiography. Intravascular US imaging can provide valuable information on the degree, eccentricity, and histologic type of stenosis before intervention, and on the morphological changes in the arterial wall and the extent of excision after intervention. Intravascular US may also serve as a superior index for gauging the diameter of balloon, stent, laser probe, and/or atherectomy catheter appropriate for a proposed intervention. Significant new insights into the mechanisms of balloon angioplasty and atherectomy have been established by intravascular US findings. Intravascular US imaging has been shown to be a more accurate method than angiography for determining the cross-sectional area of the arterial lumen, and for assessing severity of stenosis. Quantitative assessment of the luminal cross-sectional area after the balloon dilatation should be more accurate than angiography as intimal tears or dissections produced by the dilatation may not be accurately evaluated with angiography. At the present time, intravascular US is still a controversial imaging technique. Outcome studies are currently being organized to assess the clinical value and cost effectiveness of intravascular ultrasound in the context of these interventional procedures.     

Interventional radiology in oncology: inventory

A recent survey has compiled an inventory as complete as possible of the activities of interventional radiology in oncology in France. This overview has focused on identifying all invasive medical procedures whose aim was diagnosis and/or treatment of a tumor, which was carried out under guidance and under the control of an imaging means (RX, ultrasound, CT, MRI). If the biopsies represent more than half of the actions carried out under controlled imaging, recent years have seen the development of increasingly powerful therapeutic techniques.     

Cancer Concepts and Principles: Primer for the Interventional Oncologist—Part II

This is the second of a two-part overview of the fundamentals of oncology for interventional radiologists. The first part focused on clinical trials, basic statistics, assessment of response, and overall concepts in oncology. This second part aims to review the methods of tumor characterization; principles of the oncology specialties, including medical, surgical, radiation, and interventional oncology; and current treatment paradigms for the most common cancers encountered in interventional oncology, along with the levels of evidence that guide these treatments.     

Aortic emergencies

This article discusses the anatomy and pathobiology of the aorta, common aortic emergencies and their diagnosis, and the roles and limitations of diagnostic imaging in assessment, medical intervention and monitoring.     

Moderne CT- und PET/CT-Bildgebung der Leber

Computed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI.