Imaging decisions (Berlin, Germany)最新文献

Myocardial perfusion imaging (MPI) using single photon emission computed tomography (SPECT) or positron emission tomography (PET) techniques is a well-established diagnostic tool in clinical medicine providing non-invasively information about cardiac perfusion, function and prognosis in patients with coronary artery disease. Gated SPECT MPI has been used in clinical routine for years allowing the characterization of localization, extent and severity of perfusion abnormalities both in women and men. Recently, clinical studies employing nuclear techniques (e.g. BASKET or COURAGE) have underlined its diagnostic accuracy, prognostic validity and its importance for the clinical decision making. The extent of stress-induced ischaemia is of clinical relevance to guide decision making in the management of the cardiac patient. Improvements in nuclear imaging equipment, software for image analysis and stress techniques will accelerate the procedure and increase its diagnostic accuracy while reducing radiation exposure.

Time-adaptive sensitivity encoding (TSENSE) and generalized autocalibrating partially parallel acquisition (GRAPPA) were applied to a gradient-echo sequence used for first-pass myocardial perfusion imaging of 12 patients with coronary artery disease. The two parallel imaging methods were compared in terms of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and image artefacts. Image acquisition was started during the administration of a Gd-contrast bolus (0.1 mmoL/kg) followed by a 20-mL saline flush (3 mL/s), and the next perfusion was started at least 15 min thereafter using an identical bolus. The order of perfusion sequences was inverted in every other patient. Both acquisitions had an acceleration rate of 2, and were performed during breath-holding. The SNR, CNR and image quality of the GRAPPA images were significantly better than were those of the TSENSE images. An exception was the lower CNR of GRAPPA when applied after the second bolus. Differences between subjects were larger with GRAPPA perfusion imaging than with TSENSE. The SNR and CNR also varied relatively much between the GRAPPA images, indicating that the diagnostic value of TSENSE may be superior after all.

Traditionally, myocardial perfusion imaging by CT has been hampered by limited detector size and stability of Hounsfield Units in moving cardiac acquisition modes. In the present article, we describe the technical principles of a novel, dynamic heart shuttle scan acquisition using a second generation dual source CT system (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). With simultaneous injection of iodinated contrast agent, this protocol allows for sequential assessment of myocardial enhancement with reasonable radiation exposure of less than 10 mSv. We also present the case of a 69-year-old male patient who underwent dynamic CT-based myocardial perfusion imaging to determine the hemodynamic relevance of a stenosis in the left anterior descending coronary artery.

First-pass perfusion imaging with MRI under pharmacologically induced stress for the detection of myocardial ischemia has gained a lot of interest over the past years. With adenosine as the main pharmacological ‘stressor’. Issues regarding the best contrast dose and injection speed have become clear. Several perfusion sequences have been studied over the past. Even some large multi-centre trail results have been published. Some issues are still extensively research, like interpretation strategies and patient population in regard to protocols. This review highlights the technique of adenosine perfusion MRI and other perfusion techniques. The short history and current important literature are reviewed. Furthermore building blocks for different stress perfusion examinations are discussed.

Magnetic Resonance Imaging (MRI) of the chest and especially the lung is more and more accepted as a valuable additional imaging modality for several pulmonary diseases. Magnetic Resonance Imaging allows for combined morphological and functional imaging and therefore elucidates perfectly the effect of parenchymal changes and destruction onto pulmonary perfusion and ventilation. This overview presents the current status for the application of pulmonary MRI in chronic obstructive pulmonary disease as well as infectious and neoplastic diseases.

During the past decade, imaging has become of paramount importance in the diagnosis of patients with interstitial lung disorders. In addition, the quantification of radiographic features at the time of diagnosis gives important prognostic information and changes in these features over time may prove to be useful outcome variables in the study of new treatments and monitoring of patients’ response to therapy. In this chapter, we review the classification of interstitial lung diseases focusing on the role of high-resolution computed tomography (HRCT), particularly as it pertains to the need for obtaining a surgical lung biopsy. We also discuss the role of baseline and longitudinal semi-quantitative and quantitative measurement of HRCT features in assessment of patients with idiopathic pulmonary fibrosis (IPF).

A unique multi-center consortium of research centers, the severe asthma research program (SARP), is working to define asthma phenotypes, with a particular focus on severe asthma due to the higher prevalence of exacerbations and hospital visits in these patients. The consortium includes comprehensive studies of physiology, genotype, and inflammatory biomakers in addition to a lung imaging substudy in nearly 400 subjects. The imaging substudy is comparing quantitative computed tomography (CT) measures of airway morphology and parenchymal density to asthma severity and other makers of asthma. Results show increased wall thickness and increased regional air trapping in severe versus non-severe asthma. Image-guided bronchoscopic assessment using either CT or hyperpolarized gas magnetic resonance imaging (MRI) shows that highly diseased airways have increased wall thickness on histology and greater inflammatory cell numbers. Large scale imaging studies such as SARP may provide a means to better understand and guide effective treatment of severe asthma.

Management of CF patients currently relies on clinical status, lung function tests, sputum cultures and scoring systems based on chest X-ray (CXR). None of these tests give adequate information about regional lung function or are sensitive enough to demonstrate subtle changes that may aid in assessing early lung disease status, planning therapy or evaluating response to treatment. There is increasing evidence from recent studies with CT and MRI that current routine measures of lung physiology, (spirometry) and structure (CXR), may not accurately reflect disease progression nor identify early stages of lung disease, often remaining within a normal range even when significant and irreversible pulmonary damage has already occurred. Thus accurate, non-invasive, regional methods of diagnosis and follow up of CF patients based upon imaging endpoints are highly desirable. In this paper, state of the art methods of imaging signs of lung disease in the CF lung are reviewed with discussions on the technical advances in CT, proton and hyperpolarised gas MRI with example images from groups active in the area of CF lung imaging.