Venous thromboembolism (VTE) encompasses pulmonary embolism (PE) and deep vein thrombosis (DVT). DVT most commonly occurs in the deep veins of the lower extremity but can also occur in the veins of... Show moreVenous thromboembolism (VTE) encompasses pulmonary embolism (PE) and deep vein thrombosis (DVT). DVT most commonly occurs in the deep veins of the lower extremity but can also occur in the veins of upper extremity, abdomen and cerebrum. As symptoms of VTE are nonspecific, the diagnosis of VTE is based on diagnostic tests, including clinical decision rules (CDR), D-dimer tests and imaging. Although the diagnostic management of VTE has greatly advanced in recent years with the introduction of novel CDRs and high-sensitive D-dimer tests, the diagnosis may still be challenging in certain settings. The latter is mainly caused by the indirect way of thrombus visualisation by current imaging tests, such as by showing incompressibility with compression ultrasonography (CUS) or a filling defect on contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI).This thesis focuses on challenging settings for diagnosing VTE, including suspected recurrent ipsilateral DVT, upper extremity DVT, cerebral vein thrombosis and portal vein thrombosis. We studied a novel imaging technique called Magnetic Resonance Non-Contrast Thrombus Imaging (MR-NCTI) and its application in these different VTE settings. Show less
The presence of a decreased left ventricular (LV) function after myocardial infarction has demonstrated to be of considerable clinical importance. In this thesis, the role of 2D echocardiography to... Show moreThe presence of a decreased left ventricular (LV) function after myocardial infarction has demonstrated to be of considerable clinical importance. In this thesis, the role of 2D echocardiography to evaluate LV function in ischemic heart disease was investigated. In the first part of the thesis, recently introduced echocardiographic parameters to describe LV function were studied and their importance for prognosis after myocardial infarction was evaluated. In addition, in the second part of the thesis, the role for echocardiography in the decision making around advanced treatment options in heart failure such as cardiac resynchronization therapy (CRT) and cardiac surgery was explored. Show less
Cochlear implants (CIs) are a well accepted treatment for hearing impaired people. In pre- and postoperative assessment of CI-candidates imaging plays an important role to analyze anatomy, rule out... Show moreCochlear implants (CIs) are a well accepted treatment for hearing impaired people. In pre- and postoperative assessment of CI-candidates imaging plays an important role to analyze anatomy, rule out pathology and determine intracochlear positioning and integrity of the implant. Developments in CI-design, differences in surgical approach and broadening of treatment indications have raised new questions to radiologists, which were the subject of several studies described in this thesis. For optimal, a-traumatic positioning of a CI precise information about the inner ear anatomy is mandatory. We describe the development, validation and application of a method for 3-dimensional medical image exploration of the inner ear. This renders a tool to obtain cochlear dimensions on clinical computer tomography (CT) images. This will be useful for patientspecific implantplanning. It also shows an anatomical substrate for cochlear trauma during insertion. For postoperative imaging we studied the value of multislice-CT for optimal visualization of the implant within the cochlea. Its role to evaluate operation technique and electrode design, to study frequency mapping and to assess cochlear trauma is discussed. Moreover an international consensus for an objective cochlear framework is presented, forming a common ground for clear and easy exchange of findings in scientific and clinical studies. Show less
Current non-invasive detection of coronary artery disease (CAD) is based on demonstration of ischemia using stress-rest imaging: this is an indirect way of identifying CAD by demonstration of the... Show moreCurrent non-invasive detection of coronary artery disease (CAD) is based on demonstration of ischemia using stress-rest imaging: this is an indirect way of identifying CAD by demonstration of the hemodynamic consequences rather than direct visualization of the obstructive lesions in the coronary arteries. Multi-slice computed tomography (MSCT) has recently emerged as an extremely rapidly developing non-invasive imaging modality, which allows anatomical imaging of the coronary arteries, or non-invasive coronary angiography. In addition, total plaque burden, plaque morphology and (to some extent) plaque constitution can be assessed by MSCT. The technique also provides information on resting left ventricular systolic function, and possibly resting perfusion. Ideally, stress function and perfusion should also be evaluated, since this would allow detection of ischemia and would complete the picture on CAD. However, this is not routinely performed, since sequential acquisitions are associated with high radiation doses and thus pose a limitation for cardiovascular applications of MSCT. It is anticipated that, with reduction in radiation, MSCT may become an important player in the diagnostic and prognostic workup of patients with known or suspected CAD. Show less
Various modalities are available in the diagnostic and prognostic evaluation of patients presenting with known or suspected coronary artery disease (CAD). A rapidly expanding technique is... Show moreVarious modalities are available in the diagnostic and prognostic evaluation of patients presenting with known or suspected coronary artery disease (CAD). A rapidly expanding technique is noninvasive coronary angiography with Multi-Slice Computed Tomography (MSCT), which allows accurate detection of significant stenoses. The main value of the technique lies in the noninvasive exclusion of CAD in patients with intermediate pre-test likelihood. Although imaging in populations such as patients with previous stent placement appears to be more challenging, promising results have been obtained in these populations as well. However, it remains important to realize that the presence of coronary atherosclerosis with luminal obstruction does not invariably imply the presence of ischemia. Accordingly, a noninvasive angiographic imaging technique as MSCT cannot be used to predict the hemodynamical importance of lesions. In patients with borderline stenosis, therefore, functional testing (which can be performed by nuclear imaging, stress echocardiography or MRI) will remain necessary to determine management. Nonetheless, detection of CAD at a far earlier stage than functional imaging is an important advantage of MSCT. Initial investigations suggest that MSCT may distinguish different plaque characteristics between various presentations. Potentially, this information could be useful for risk stratification. Finally, additional non-coronary information can be derived as well. LV function can be evaluated with high accuracy while also information on the cardiac venous system can be obtained. Show less
