A three-dimensional ultrasonographic quantitative analysis of non-ulcerated carotid plaque morphology in symptomatic and asymptomatic carotid stenosis.

BACKGROUND AND PURPOSE: Studies evaluating the association between carotid plaque composition and occurrence of ischemic cerebrovascular disease reveal inconsistent results. This study correlates the carotid echomorphology with the degree of stenosis in symptomatic and asymptomatic patients. METHODS: We included consecutive patients with hemispheric stroke or asymptomatic carotid artery stenosis assessed with 2D ultrasound. The echomorphology was assessed with mean gray value (MGV) of the three-dimensional (3D) volume. We used the free-hand approach for 3D image and volume acquisition. Analyses of the stored carotid plaque volumes were carried out offline using the Virtual Organ Computer-aided Analysis (VOCAL) program. RESULTS: We studied 110 symptomatic and 104 asymptomatic atherosclerotic carotid plaques. MGV was lower in symptomatic carotid plaques causing <70% stenosis compared to plaques causing > or =70% stenosis (25.95+/-7.40 vs. 32.16+/-11.35, p=0.002). There was no difference in MGV between plaques producing <60% and those with > or =60% in asymptomatic patients (32.08+/-8.36 vs. 31.46+/-9.25, p=0.724). There were significant differences in MGV between symptomatic and asymptomatic plaques causing <60 or <70% stenosis; MGV was lower in symptomatic patients. CONCLUSIONS: Lower plaque echogenicity is observed in symptomatic than in asymptomatic patients with moderate degree of carotid stenosis, indicating that it is a significant factor for the production of cerebral ischemia. Our method could be useful in assessing the risk of cerebral ischemia and the response of carotid artery atherosclerosis to medical therapies.

Maximal voluntary ventilation in myasthenia gravis.

Assessment of respiratory muscle weakness is important at all stages of myasthenia gravis. The maximal voluntary ventilation (MVV) is an objective dynamic method for measuring the working capacity of respiratory muscles. The clinical value of this method was studied in 24 newly diagnosed patients with myasthenia gravis, classified according to Osserman criteria (grades I, IIa, and IIb). The MVV values were normal in group I, whereas a characteristic "myasthenic pattern" of decremental respiratory volumes was demonstrated during MVV in group IIa and IIb patients, with or without dyspnea. Despite some limitations and lack of specificity, MVV may be a valuable tool in the assessment of respiratory dysfunction in patients with myasthenia gravis. Muscle Nerve, 27: 715-719, 2003