MRI of Aortic Atherosclerosis

Mri Atherosclerosis

Imaging the aorta with MRI may have clinical usefulness (Fig. 2). Assessing and monitoring plaque burden in the aorta will allow for monitoring response to anti-atherosclerosis therapy. Aortic atherosclerosis has been previously show to be associated with a higher risk of ischemic stroke or cerebrovascular infarction (71-73). Additionally, plaque burden in the aorta may serve as a surrogate marker of systemic plaque burden. Furthermore, by imaging the aorta we may also gain screening...

References

Molecular imaging. Radiology 2001 219 316-333. 2. Luker GD, Piwnica-Worms D. Beyond the genome molecular imaging in vivo with PET and SPECT. Acad Radiol 2001 8 4-14. 3. Wagenaar DJ, Weissleder R, Hengerer A. Glossary of molecular imaging terminology. Acad Radiol 2001 8 409-420. 4. Sharma V, Luker G, Piwnica-Worms D. Molecular imaging of gene expression and protein function in vivo with PET and SPECT. J Mag Reson Imaging 2002 16 336-351. 5. Massoud T, Gambhir S....

Atherogenesis And Atherosclerosis

Atherogenesis can begin early in life with EC activation (2). The pathological process is initiated by lipid deposition seen early in the subendothelial space with resultant inflammatory cell infiltration. In the presence of high circulating levels, LDL cholesterol is taken up by the endothelium. Passing through caveoli, LDL becomes trapped in the subendothelial extracellular space (3). This impairs the secretion of vasodilatory and anti-inflammatory factors, such as NO (4). The altered...

Plaque Erosion

While thin-capped fibroatheroma are the pathological hallmark lesion for vulnerable plaque in older men and women a different lesion in found in younger women and some younger men who die suddenly from coronary thrombosis. In this lesion, the endothe-lium erodes exposing intima containing predominantly SMCs and proteoglycans and minimal inflammatory cells (12). Erosions are found at approximately 40 of autopsy specimens of coronary arteries from sudden death victims (14). This lesion is more...

Uncorrectedsusceptibility corrected T2imsi

Figure 6 T2* maps of water tubes fill with SPIO contrast agents (A). Without susceptibility correction, no significant differences can be observed between the different tubes. After correction, SPIO concentrations as low as 5 standard deviation above the noise level could be detected. In-vivo T2* maps of the liver before and after susceptibility correction (16). Figure 6 T2* maps of water tubes fill with SPIO contrast agents (A). Without susceptibility correction, no significant differences can...

Quantification Of Myocardial Blood Flow And Metabolism In Rodents

Once the technical aspects for quantifying blood and myocardial activity have been optimized it is then possible to apply well validated kinetic models to measure biologically relevant parameters such as MBF and myocardial metabolism. Discussed below are two such examples. MBF Alterations in MBF are central to normal cardiac performance and play key role in a variety of cardiac disorders such as myocardial ischemia, left ventricular hypertrophy and heart failure. Using well-validated...

Clinical Studies

Histopathologic validation of qualitative and quantitative image criteria ex vivo provided a foundation for interpreting data obtained from living human patients. Between January 2000 and September 2003, a total of 83 patients undergoing routine percutaneous transluminal coronary intervention PTCI were enrolled in a study at the Massachusetts General Hospital Boston, Massachusetts, U.S.A. to investigate the feasibility of intracoronary OCT. Imaging was performed in culprit lesions and remote...

Mri Of Atherosclerosis Multi Contrast MRI of Atherosclerosis

Multi-contrast MRI entails delineating different components of atherosclerotic lesions by generating T1-weighted, T2-weighted and proton-density weighted images of plaque 18,37,38 . This has largely become possible because of faster imaging methods, the ability to perform high-resolution scans and better detection coils RF coils . The multi-contrast MRI approach involves characterization of plaque based upon signal intensities as well as morphologic appearance of various plaque components on...

Targeted Microbubble Design And Detection

Microbubble Resonance

Acosutically active agents for molecular imaging have been developed using two different targeting strategies Fig. 3 . The first and more simple strategy involves the manipulation of the chemical or charge properties of the microbubble or microparticle shell. The shells of microbubbles, nanoparticles, or liposomes may also be modified by the surface conjugation of ligand molecules, such as monoclonal antibodies, peptides, glycoproteins, etc. Most formulations involve surface conjugation of...

MicroPET Technology

Micropet Focus 220

The prototype microPET scanner was developed by Cherry et al. 42 at UCLA in 1996. Its technology was made commercially available by Concorde Microsystems Inc., Knoxville, Tennessee, U.S.A. now part of Siemens Molecular Imaging in 2000. The second prototype system, microPET II, was completed in 2002 at UC Davis by the same group 49 , and the third generation microPET developed at Concorde was revealed in 2003 Focus 220 51 and 2004 Focus 120 52 . Figure 10 shows photographs of the micro PET...

Intravascular Ultrasound Imaging

Ivus Imaging Dissection

To help diagnose and treat cardiovascular disease, intravascular ultrasound imaging was developed to visualize arterial pathologies from the vessel lumen. IVUS Image of Diseased Coronary Artery with Intimai Flap IVUS Image of Diseased Coronary Artery with Intimai Flap IVUS Image of Dissection post Balloon Angioplasty Figure 1 Two typical B-Mode clinical images obtained with a 3.5F imaging catheter. Left A diseased artery with an intimal flap. Right Arterial dissection post angioplasty on the...

Development In Animal Handling Techniques

Isoflurane Nose Cone

The first hurdle in obtaining quantitative data, in particular in mice, is the development of animal handling methods that result in minimal trauma to the animals. Furthermore, in PET studies of the heart, multiple tracer administrations to a single animal are frequently necessary to perform measurements of both myocar-dial perfusion and the metabolism of various substrates such as oxygen, glucose, and fatty acids. Due to the inherent rapid kinetics of flow and metabolic PET...

Cardiac Reporter Gene Imaging Studies

Drug Metabolism Phase1 Phase2 Reaction

While most molecular imaging studies have focused on cancer biology 33,34 , only recently has reporter gene imaging of cardiac transgene expression been investigated. In the following section, a summary of some of the most relevant studies published over the past years will be discussed. In the first proof-of-principle study involving cardiac optical bioluminescence imaging, adenovirus with a constitutive cytomegalovirus CMV promoter driving firefly luciferase reporter gene Ad-CMV-Fluc 1x109...

Radiopague Indicators Of Physiological Spaces And Processes

Diagram Pulmonary Artery Wedge

Essentially all current X-ray micro-CT scanners, like clinical CT scanners, use the attenuation of the X-ray by tissues as the signal for generating the X-ray images. In micro-CT scanners, this means that for a given X-ray photon energy the contrast signal is most closely related to the atomic number Z and the concentration of that element 45 . At the X-ray exposures tolerated by living tissues, this means that the signal-to-noise in the CT image is adequate primarily for differentiating air,...

Imaging Capability of microPET

Microderenzo

High-resolution imaging capability of microPET is demonstrated in Figure 13. A micro-Derenzo phantom with hot rods of different sizes was imaged by P4, Focus 220 and microPET II. The diameter of rods is 0.8, 1.0, 1.25, 1.5, 2.0, and 2.5 mm respectively. The center-to-center distance between adjacent rods is 2 times the rod diameter. It is evident that Focus 220 has a higher resolution than P4, while the microPET II has the highest resolution. With the maximum a posteriori MAP 65,66...

Random and Scatter Corrections

Scatter Coincidence

The coincidence events detected by a PET scanner can be divided into three categories Fig. 7 . If the annihilation photons escape the object without any interaction and subsequently become detected by the scanner, this is defined as a true coincidence, illustrated as event A. If at least one of the two 511 keV photons is scattered by the object, such as event B in Figure 7, this is a scattered coincidence. If two uncorrelated 511 keV photons are detected within the predefined timing window,...

Implementation of Correction Techniques in microPET

Random coincidences were initially measured by all microPET systems using the delay-window technique. Figure 11 Photographs of various microPET detectors. A Detectors of the prototype microPET top and microPET II bottom . The MC-PMT in the prototype detector was much larger and required long optical fibers. microPET II detector uses fused optical fiber bundle, compact MC-PMT and 14 x 14 elements LSO array with sub-millimeter crystal width as shown in C next to a penny . B Detector in the first...