Imaging decisions (Berlin, Germany)最新文献

F-18 FDG positron emission tomography (PET) is able to diagnose viable lymphoma tissue due to its elevated glucose metabolism, independent of the size of the lesions. For staging purposes, the value of FDG PET in Hodgkin’s (HL) and high-grade non-Hodgkin lymphoma (NHL) lies predominantly in a change of tumour stage with the consequence of a modification of therapeutic regimen and a more exact definition of radiotherapy (RTX) planning volume. In indolent lymphoma, a pre-therapeutic scan is mandatory for further therapy monitoring due to variable FDG-uptake. In restaging HL and NHL, discrimination between viable residual lymphoma and necrosis in case of a residual bulk is possible with FDG PET, which is limited by conventional methods. PET/CT combines the advantages of PET and CT and performs better than each method alone by further improving the accuracy of staging and response assessment over that of CT alone. There are a lower proportion of equivocal or benign findings because PET-CT specifies the nature of uptake. Some studies have demonstrated the possibility of therapy monitoring, but further prospective studies have to be performed before therapy may be avoided or modified according to the results of the PET/CT examination.

F-18 fluorodeoxy-glucose (FDG) is the most widely used tracer in positron emission tomography (PET) imaging in Nuclear Medicine. This review deals with the clinical value of other F-18 labelled PET tracers targeting different biological substrates.

Positron emission tomography (PET) is the most advanced scintigraphic imaging technique used for in vivo assessment of cardiac pathophysiology. Very recently, 16- and 64-slice hybrid PET- computed tomography (CT) scanners have been introduced into clinical routine allowing the comprehensive work up of patients with coronary artery disease (CAD). The integration of radionuclide imaging of myocardial perfusion with multidetector CT scanners (i.e. PET-CT) provides the opportunity to detect cardiac and vascular anatomic abnormalities, and their potential clinical consequences, within a single session. Hybrid imaging offers a unique strategy to assess the cardiovascular risk of patients with known or suspected CAD. This includes the detection and quantification of the extent of calcified and non-calcified plaques via coronary artery calcium and coronary angiography, and extends to the quantification of vascular reactivity and endothelial health, the identification of haemodynamically relevant coronary stenoses with the extent of myocardial area at risk, and in the end the assessment of myocardial viability. Dedicated PET-CT protocols have been developed to answer many complex clinical questions. Taken together cardiac hybrid imaging can provide all information to increase the accuracy of noninvasive diagnosis of CAD, to assess cardiac risk, to monitor its course and to improve the clinical decision-making in the management of cardiac patients.

We assessed whether radiologists’ reading of the CT portion of the PET-CT identifies significant additional lesions and whether these findings result in major clinical management changes.

716 consecutive patients (pts) aged 13–87 underwent FDG PET-CT scans for known or suspected cancer between 07/05–03/06. Only those pts without a diagnostic CT within 1 month prior to the PET-CT were included. The CT portion of the PET-CT was read by a nuclear medicine or radiology resident or fellow with 1 of 3 designated radiologists and dictated separately from the PET report, which was read with 1 of 5 nuclear medicine faculty physicians. Typically the PET portion was read on the day of scan and CT portion next morning. The radiologists were aware of the PET results and had access to fused PET-CT images. The PET-CT system used was a 2-slice Siemens Biograph. Particular attention was paid to 5 major findings, which are not FDG avid: small pulmonary nodules, lymph nodes, pneumothorax, aortic aneurysm, and renal cell carcinoma. Other CT findings were listed as minor.

The major findings identified by radiologists, but not mentioned by nuclear medicine faculty, were FDG-negative lung nodules (typically sub-cm) in 91 pts (12.8%), 43 FDG-negative lymph node/soft tissue masses (6.0%), 1 pneumothorax, 1 pneumoperitoneum, 15 aortic aneurysms (1.9%) and no renal cell carcinoma. This resulted in 21% of all patients having findings. However, major clinical management changes as a result of these findings only occurred in 3 pts: one with a 7-cm AAA who underwent endograft repair and another patient with enlarged right iliac lymph nodes that were subsequently excised. The pt with pneumothorax did not require chest drain. The pt with pneumoperitoneum underwent laparotomy for perforation of duodenal ulcer. The remaining 7 aneurysms are being followed, as are the cases of small pulmonary nodules. Among the minor radiology findings were: calcified granulomas 122 (17%), atherosclerotic calcifications 77 (10.8%), kidney/liver cysts 35 (4.9%), emphysema 39 (5.4%), gallstones 21 (2.9%), and pericardial effusion 19 (2.7%). None of these led to major clinical management changes.

The reading of the CT portion of a PET-CT study often identifies FDG-negative lesions; however, it infrequently leads to major clinical management changes in oncology patients. Nevertheless, given the severity of some of these findings, it seems warranted that that the CT portion of the examination be carefully examined by a physician with appropriate CT experience.

Current computed tomography (CT) technology allows for isotropic, sub-millimetre resolution acquisition of the thorax in a few seconds. These thin-slice chest scans have become indispensable in thoracic radiology, but have also increased the time and effort required from radiologists for reporting. Industry has focused on the development of computer-aided diagnosis (CAD) tools to facilitate the interpretation of thoracic CT data. In this paper I discuss the three most ‘senior’ CAD applications for chest CT: nodule detection, nodule volumetry and quantification of emphysema. Are these applications ready for widespread application?

In breast cancer imaging many innovations continue to take place. This article discusses computer-aided detection (CAD) of breast cancer in mammograms, which is the first large-scale application of independent computerized interpretation of radiological images. Thousands of systems have already been installed worldwide and use of CAD is rapidly expanding with the introduction of digital mammography. Radiologists are generally pleased with the new technology, in particular for its ability to mark clustered microcalcifications with high sensitivity. However, most believe that the performance of CAD for mass detection should still be improved to make it more useful. Most clinical studies indicate that CAD is effective in practice, both for detection of masses and microcalcifications. Future developments show a trend towards using CAD not only for detection but also for characterization of lesions.

The aim of this study is to give an overview on the accuracy of the discrimination between benign and malignant breast lesions on MRI with and without the use of a computer-aided detection (CAD) system. One investigator selected relevant articles based on title and abstract. Ten articles were selected for this review. The CAD systems used in these articles were commercially available (CAD stream and 3T) or institution-specific computer analysis system. The articles showed that CAD has the potential to improve the discrimination of benign from malignant breast lesions at MRI imaging, but there is insufficient evidence to assess whether the use of CAD systems would maintain or increase the sensitivity and specificity.