PubMed · 12924691
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Fredric B Meyer. 2003. Small aneurysms.. https://doi.org/10.3171/jns.2003.99.2.0220
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Although ultrasonography is an important cost-effective imaging modality, technical improvements are needed before its full potential is realized for accurate and reproducible monitoring of disease progression or regression. Two-dimensional viewing of three-dimensional anatomy, using conventional ultrasonography, limits our ability to quantify and visualize pathology and is partly responsible for the reported variability in diagnosis and monitoring of disease progression. Efforts of investigators have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that are capable of acquiring B-mode images using existing conventional ultrasound systems, reconstructing the information into 3D images, and then allowing interactive viewing of the 3D images on inexpensive desktop computers. In addition, the availability of 3D ultrasound images has allowed the development of manual and semi-automated techniques to quantify normal and abnormal anatomical volumes. In this paper we review our semi-automated 3D segmentation approaches for segmenting the surface of the carotid arteries and plaques, and segmenting the prostate. These techniques demonstrate that efficient segmentation techniques can be used with 3D ultrasound images to quantify anatomical organ volumes and morphology.
OBJECTIVE: Large-vessel arterial disease is increasingly recognized as a major cause of morbidity in autoimmune rheumatic disorders. Recent evidence suggests that scleroderma (systemic sclerosis, SSc) may be linked to altered fibrillin-1 metabolism associated with a defect in chromosome 15q. If this is the case, we may expect to see changes in the arterial wall mechanics of large vessels not clinically involved in the disease process. We undertook a study to determine whether the biomechanical properties and intima-media thickness (IMT) of the elastic carotid artery and the muscular femoral artery are altered in subjects with limited (lcSSc) and diffuse (dcSSc) cutaneous SSc. METHODS: Measurements of carotid and femoral wall mechanics were made in 33 patients with lcSSc, 19 patients with dcSSc and 21 control subjects, using a duplex scanner coupled to a Wall Track system. Their age, gender, body mass index, heart rate, systolic and diastolic blood pressures, presumed cardiovascular load, and plasma creatinine, fasting cholesterol, triglyceride and glucose concentrations were also measured. RESULTS: There was a progressive and significant reduction (P < 0.001) in the elastic properties of the carotid artery from the control group (compliance, 16.24 +/- 4.39 %mmHg(-1) x 10(-2)) to the lcSSc group (10.89 +/- 2.43 %mmHg(-1) x 10(-2)) to the dcSSc group (7.65 +/- 2.08 %mmHg(-1) x 10(-2)), even after adjustment for the systemic physiological and biochemical variables studied, which are known to influence the mechanics of arterial walls. There was no apparent difference between the groups in the mean elastic indices of the femoral artery and the IMT of the carotid and femoral arteries. CONCLUSION: The elastic properties of the carotid artery are significantly altered in SSc, and the two major subsets of SSc may be distinguished by their carotid artery biomechanics. This suggests that connective tissue abnormality occurs at sites not previously assessed.
BACKGROUND: One of the features of high-risk atherosclerotic plaques is a preponderance of macrophages. Experimental studies with hyperlipidemic rabbits have shown that ultrasmall superparamagnetic particles of iron oxide (USPIOs) accumulate in plaques with a high macrophage content and that this induces magnetic resonance (MR) signal changes. The purpose of our study was to investigate whether USPIO-enhanced MRI can also be used for in vivo detection of macrophages in human plaques. METHODS AND RESULTS: MRI was performed on 11 symptomatic patients scheduled for carotid endarterectomy before and 24 (n=11) and 72 (n=5) hours after administration of USPIOs (Sinerem) at a dose of 2.6 mg Fe/kg. Histological and electron microscopical analyses of the plaques showed USPIOs primarily in macrophages within the plaques in 10 of 11 patients. Histological analysis showed USPIOs in 27 of 36 (75%) of the ruptured and rupture-prone lesions and 1 of 14 (7%) of the stable lesions. Of the patients with USPIO uptake, signal changes in the post-USPIO MRI were observed by 2 observers in the vessel wall in 67 of 123 (54%) and 19 of 55 (35%) quadrants of the T2*-weighted MR images acquired after 24 and 72 hours, respectively. For those quadrants with changes, there was a significant signal decrease of 24% (95% CI, 33% to 15%) in regions of interest in the images acquired after 24 hours, whereas no significant signal change was found after 72 hours. CONCLUSIONS: Accumulation of USPIOs in macrophages in predominantly ruptured and rupture-prone human atherosclerotic lesions caused signal decreases in the in vivo MR images.