Current opinion in radiology最新文献

The acquisition of medical images and their display, manipulation, and applications have advanced significantly in the recent past. MR imaging using ultrafast echo planar and fast gradient-echo techniques have expanded application in cardiovascular studies, as well as in the brain and spinal cord. Spiral CT has the potential to revolutionize a well-established modality, subject to several important limitations. The postprocessing of medical sectional images from MR imaging, CT, ultrasound, positron emission tomography, and single-photon emission CT has rapidly grown in importance. We have seen the emergence of renewed and expanded applications of these images, suitably processed, in directing planning and performance of therapeutic procedures on patients through stereotactic techniques, intravascular ultrasound, robot surgery, and integrated displays. This more central role of three-dimensional imaging to medical care is new and will continue to grow. Research applications have recently appeared in neuromorphometry, multimodality registration, functional neuroimaging, quantitative coronary angiography, and saturation MR techniques for myocardial tissue tagging.

Interest in fine-needle aspiration cytology (FNA) and core biopsy of nonpalpable breast lesions as an alternative to surgical biopsy has increased during the past year. The most accurate results have been reported with large-core needle biopsy using a dedicated prone stereotactic unit and stereotactic FNA biopsy obtained with an onsite cytopathologist determining sample adequacy. Ultrasound-guided needle biopsy using either FNA or core is another important technique. Questions remain concerning 1) the accuracy of FNA and core compared to surgical biopsy; 2) the efficacy of needle guidance by a mammographic add-on upright unit, dedicated prone table, or ultrasound; and 3) the lesions best suited for various biopsy techniques. Currently these nonsurgical biopsy methods are most appropriately used in conjunction with mammographic-histologic or cytologic correlation and a careful clinical management plan.

Trauma is the leading cause of death in people less than 40 years of age. Blunt and penetrating chest trauma mechanisms and the resultant injuries and complications are reviewed in respect to the chest wall, pleura, lungs, mediastinum, and diaphragm. Recent literature reviewed includes a useful sign of flail chest, the costal "hook sign." New evidence suggests that traumatic aortic rupture may be more common in the pediatric population than was previously reported. The diagnostic evaluation of traumatic aortic rupture continues to be controversial, with imaging modalities ranging from chest radiographs and angiography to CT, MR imaging, and transesophageal echocardiography. Recent integration of these methods has brought to the literature a newly proposed algorithm for the work-up of suspected aortic rupture. Survival and modifying factors in adult respiratory distress syndrome and a comprehensive review of esophageal disease, including trauma, are also presented.

This review covers the papers that we believe represent the most interesting and innovative developments in hilar and mediastinal imaging over the past year. One of the most exciting of these is the expanded role for sonography in imaging extracardiac mediastinal pathology. A number of reports highlight its use in directing mediastinal biopsy, for tissue characterization, and for staging lymphoma. The comparative merits of CT and MR imaging in staging bronchogenic carcinoma have been further clarified. The past year has also seen further attempts to characterize tumor versus postobstructive pneumonitis or collapse using MR imaging and CT. Other useful clinical work includes the documentation of signs distinguishing paramediastinal lung masses from primary mediastinal pathology. References are also made to clinically relevant aspects of MR scanning and advances in imaging of the airway, particularly cine and high-resolution CT of the trachea.

Picture archiving and communication systems (PACS) are expected to replace film in the years to come. PACS acquire, store, transmit, and display medical images. Although there are several clinical PACS in operation today, there are significant problems slowing their introduction. PACS are limited in spatial and contrast resolution and the workstation's displays present difficulties due to low light levels, slow image presentation, and poorly designed software. Standard interfaces are still lacking for most of the imaging equipment currently in use, making connections to these devices nearly impossible. Cost is a major issue as well. Yet limited implementations, often called mini-PACS, offer advantages such as faster image presentation to radiologists and referring physicians, reduced portable retake rates, the capability for viewing images at home off-hours, and transmission from remote sites. More development is needed for interfaces with the radiology information system and for sophisticated network and image management.

Breast biopsy recommendations are commonly made on the basis of mammographic findings. Benign breast biopsies secondary to false positive mammographic interpretation remain a major source of discussion. A review of recent series of biopsy results is presented and the factors influencing positive predictive value are discussed. Methods to improve mammographic specificity, including validity of certain mammographic signs such as mass density are summarized. Issues relating to lesions followed on mammography--including number of views, compliance, and patient anxiety--are also addressed.

The literature of the past year regarding interventional procedures in the thorax covers aspects of transthoracic needle biopsy, drainage of pleural fluid collections, percutaneous management of lung abscess, and thoracic vascular interventions. Topics in transthoracic needle biopsy include a large retrospective series on fluoroscopically guided biopsy of thoracic masses; several reports reviewing experience with diagnosis of anterior mediastinal masses, including four studies describing the use of real-time ultrasound guidance for this procedure; the description of a new automated cutting needle for consistent tissue sampling; and two studies addressing factors affecting pneumothorax and chest tube insertion rates following transthoracic needle biopsy. Reports on percutaneous management of pleural fluid collections are highlighted by a paper reporting the results of ultrasound-guided drainage and sclerosis of malignant pleural effusions. Ultrasound-guided percutaneous aspiration of lung abscess for isolation of causative bacteria is the basis of two recent papers, and successful CT-guided drainage of lung abscesses is described by a group of researchers that has written extensively on a variety of the interventional thoracic procedures that are currently performed. Finally, the failures and complications associated with bronchial and pulmonary arterial embolization procedures have been reviewed.

The superiority of CT over chest radiography in the evaluation of diffuse lung disease is now acknowledged, and the role of high-resolution CT is becoming increasingly clearly defined. In many cases of suspected diffuse lung disease, open lung biopsy may be obviated as a result of the findings of high-resolution CT. Now that the high-resolution CT appearances of most diffuse lung diseases have been described, studies are being directed at characterizing the natural history of these conditions using serial high-resolution CT examinations. This work is of particular relevance to industrial and fibrosing lung disease. Faster image acquisition by the latest CT scanners has allowed dynamic studies that have provided unique functional information in a number of diffuse lung diseases.

Mammographic technique has gone through a continuous change during the past decade with the advent of new dedicated mammographic units, new screen-film systems, molybdenum anode material, small focal spots, specially designed grids to reduce scattered radiation, very accurate automatic exposure control units, and so forth. The user side has also gone through many changes with the development of better ergonomics of the units, better and quicker compression, easy-to-load cassettes, advanced automatic exposure controls, and other advancements. Many of these new features have come to reality due to the screening projects going on in many countries. These projects often demand that approximately 100 patients are examined on one unit per day, and from this heavy demand, many new features have been developed. Screening has also brought patient-absorbed dose to the foreground. This concern is natural because large populations of healthy women are irradiated. In turn, this concern has made extended-cycle film development more desirable. Many new test phantoms that can be used to optimize and to maintain image quality have been developed. The large demand for throughput during screening requires very constant image quality during a single day, and week after week, making quality control a vital and critical necessity.