Eccentric stenosis of the carotid artery associated with ipsilateral cerebrovascular events.

BACKGROUND AND PURPOSE: Eccentric stenosis of the coronary artery is associated with plaque disruption and acute coronary syndrome. The purpose of the present study was to determine whether eccentric stenosis of the carotid artery contributes to cerebrovascular events. MATERIALS AND METHODS: Of 6859 patients with vascular diseases who underwent duplex carotid ultrasonography, we studied 512 internal carotid arteries in 441 patients who had a maximum area stenosis at or more than 70%, which corresponds with approximately 50% or more by the NASCET method. The maximal (A) and minimal wall thicknesses (B) were measured on cross-sectional sonography images, and an eccentricity index was calculated using the following formula: (A - B)/A. Arteries in the lowest quartile of the eccentricity index (<0.69) were defined as having a concentric stenosis, whereas the others were defined as having eccentric stenosis. The underlying clinical characteristics and plaque morphologies, as well as the occurrence of ipsilateral ischemic stroke or transient ischemic attack in the preceding year, were compared between patients with eccentric and concentric stenosis. RESULTS: Patient characteristics and plaque morphology were similar between the 2 groups. Cerebrovascular events occurred more frequently ipsilaterally to the artery with eccentric stenosis (13.5%) than to the artery with concentric stenosis (5.5%; P = .013); the difference was more evident when cerebrovascular events of presumed carotid arterial origin were assessed (P = .005). After adjusting for risk factors and plaque morphology, eccentric stenosis was independently related to the presence of recent cerebrovascular events (odds ratio = 2.76; 95% confidence interval = 1.19-6.40). CONCLUSIONS: In patients with an area carotid stenosis of 70% or more, eccentric plaque was associated with a significantly increased incidence of ipsilateral cerebrovascular events compared with patients with concentric stenosis.

Association between signal hyperintensity on T1-weighted MR imaging of carotid plaques and ipsilateral ischemic events.

BACKGROUND AND PURPOSE: To investigate associations between cerebral ischemic events and signal hyperintensity in T1-weighted MR imaging (T1WI) of carotid plaque according to stenosis severity and to estimate persistence of T1WI signal hyperintensity. METHODS: A total of 222 patients (392 atherosclerotic carotid arteries) underwent plaque imaging using 3D inversion-recovery-based T1WI (magnetization-prepared rapid acquisition with gradient-echo [MPRAGE]). Carotid plaque with intensity on MPRAGE of >200% that of adjacent muscle was categorized as "high signal intensity" and correlated with ipsilateral ischemic events within the previous 6 months. A total of 58 arteries (35 patients) underwent repeat MR imaging a total of 70 times at a median interval of 279 days (range, 10-1037 days). RESULTS: Ipsilateral ischemic events were more frequent in patients with MPRAGE high signals than in patients with low signals in the 0%-29%, 30%-69%, and 70%-99% stenosis groups: Relative risk (95% confidence interval) was 2.50 (0.96-6.51), 7.55 (1.84-31.04), and 1.98 (1.01-3.90), respectively. In the 70 cases of repeat MR imaging, 29 of 30 cases with high signals on the preceding MR imaging maintained high signals. Of the 58 arteries that underwent repeat MR imaging, 4 of 22 carotid arteries with high signals developed ipsilateral subsequent ischemic events within 1 year, whereas none with low signals developed subsequent events. CONCLUSIONS: Carotid plaque signal hyperintensity on T1WI is strongly associated with previous ipsilateral ischemic events, persisting over a period of months, and may indicate risk of subsequent events. Larger clinical trials are warranted to clarify associations between signal hyperintensity and risk of subsequent cerebral ischemic events.

Glucose utilization in the inferior cerebellar vermis and ocular myoclonus.

In a patient with symptomatic ocular myoclonus, the authors observed the regional cerebral metabolic rate of glucose use (rCMRGlu) before and after successful treatment with clonazepam. Even after the symptoms resolved, the rCMRGlu in the hypertrophic olive increased persistently, whereas that in the inferior cerebellar vermis contralateral to the hypertrophic olive decreased. The inferior cerebellar vermis, belonging to the vestibulocerebellar system, may be associated with the generation of symptomatic ocular myoclonus.

Coiling is Not Essential to Anhydrobiosis by Aphelenchus avenae on Agar Amended with Sucrose.

The roles of preconditioning and coiling upon entrance into anhydrobiosis by Aphelenchus avenae were tested via video-assisted analysis at 25(2) degrees C. Fourth-stage juveniles or young adults of A. avenae were individually placed on 5% agar containing 0.8 M sucrose. Nematodes became quiescent within 3 hr, then gradually resumed a low level of activity and assumed a coiled posture. High desiccation survival rate was recorded when nematodes were incubated on agar for more than 6 hr; the survival rates were 0%, 3%, 73%, and 92% for 0, 2, 6, and 12 hr on agar, respectively. All nematodes placed on agar for 24 hr or more revived after rehydration following desiccation. Once nematodes were on agar for a sufficient time, no difference in desiccation survival was observed between nematodes taking a coiled posture and those uncoiled artificially. Based on these results, exposure to osmotic stress for 6 hr can prepare A. aveae physiologically for anhydrobiosis, but coiling does not appear to be a physiological requirement for desiccation in survival.

Successful application of three-dimensional transcranial power Doppler imaging in two stroke patients.

We applied a new technique of three-dimensional (3-D) transcranial power Doppler imaging to demonstrate the middle cerebral artery (MCA) in the 2 stroke patients. In the first patient, the 3-D power Doppler study clearly showed the horizontal portion, bifurcation, proximal portion of the upper and lower trunks, and the major branches of the lower trunk of the MCA. In the second patient, the 3-D power Doppler clearly revealed the proximal bifurcation of the left MCA. The 3-D transcranial power Doppler seems to be useful in making clear 3-D images of the MCA.

[Right-to-left shunt and atrial septal aneurysm in stroke patients: a contrast transesophageal echocardiographic study].

BACKGROUND: Transesophageal echocardiography (TEE) has been used to detect cardiac abnormalities including right-to-left shunt (RLS) and atrial septal aneurysm (ASA). The aim of this study was to elucidate frequency of RLS and ASA detected by contrast-TEE, and to evaluate the role of these abnormalities in stroke patients. METHODS AND RESULTS: We investigated prevalence of RLS and ASA in 504 patients suspected of stroke by using TEE. (mean age 62 +/- 12 y.o., stroke 491, non-stroke 13). The RLS was detected in 64 patients (12.7%), in whom 49 patients (9.7%) had the patent foramen ovale (PFO). The ASA was demonstrated in 10 patients (2.0%), and accompanied well with the RLS (six of the 10, 60%). The prevalent ratios of the RLS (33.8%), the PFO (26.8%), and the ASA (11.3%) in 71 patients with embolic stroke (brain embolism or TIA) of unknown cause were significantly higher than those in the other 433 patients (9.2%, 6.9%, 0.5%, respectively, p < 0.0001). Multiple logistic regression analysis showed that both the PFO and the ASA were independent risk factors (odds ratio: 3.8: p = 0.0002 and 16.6: p = 0.0008, respectively) for embolic stroke of unknown cause. CONCLUSION: It seems that the RLS, PFO and the ASA play a roll in developing embolic stroke of unknown cause.

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors. II.

A series of phenoxyacetanilide derivatives was synthesized and their antagonist activities for human gastrin/cholecystokinin (CCK)-B and CCK-A receptors were evaluated. Among the compounds synthesized, 2-[3-[3-[N-[2-(N-methyl-N-phenylcarbamoylmethoxy)phenyl]-N-(N-meth yl-N- phenylcarbamoylmethyl)carbamoylmethyl]-ureido]phenyl]acetic acid (20i, DA-3934) exhibited high affinity for gastrin/CCK-B receptors and high selectivity over CCK-A receptors. DA-3934 and its methyl ester derivative inhibited pentagastrin-induced gastric acid secretion in rats in a dose-dependent manner.

Transoral carotid ultrasonography.

BACKGROUND AND PURPOSE: We attempted ultrasonographic evaluation of the distal extracranial internal carotid artery (ICA) using the transoral method (transoral carotid ultrasonography [TOCU]). METHODS: The subjects consisted of five healthy volunteers and seven stroke patients. Examinations were performed with a color Doppler flow imaging system equipped with convex array transducers (7 or 9.5 MHz), originally designed for transrectal use. After local anesthesia of the pharynx, we inserted a probe covered with thin gum transorally, touching the tip to the pharyngeal posterolateral wall. We then attempted to detect the ICA and measure flow velocity of the distal extracranial ICA using principal images obtained by TOCU. RESULTS: TOCU was successfully performed in all subjects without any difficulty. In the healthy volunteers, the ICA was identified at a depth of 2.2+/-0.6 cm and visualized as a vertical linear vessel 2.9+/-0.3 cm in length and bent slightly backward. The diameter and mean flow velocity of the distal extracranial ICA were 4.7+/-0.2 mm and 50+/-7 cm/s, respectively. In the stroke patients, some remarkable findings were obtained, including a narrow ICA with low flow velocity in a patient with possible ICA dissection, a lucent echo without flow signal in a patient with acute cardioembolic ICA occlusion, and decreased ICA flow velocity in a patient with ipsilateral MCA stenosis. CONCLUSIONS: These preliminary data demonstrate the potential applicability of TOCU to the evaluation of flow in the far distal extracranial ICA. TOCU definitely warrants further investigation in patients with carotid artery disease.

Diagnosis of middle cerebral artery stenosis by transcranial color-coded real-time sonography.

BACKGROUND & PURPOSE: This study was performed to determine the usefulness of transcranial color-coded real-time sonography (TCCS) in detecting stenosis in the horizontal portion of the middle cerebral artery (MCA). METHODS: Using TCCS and the incident angle correction technique, we measured the peak-systolic flow velocity in bilateral MCAs in 45 consecutive patients in whom cerebral angiography was carried out within 1 week before or after TCCS. Three patients had a stenosis of 75% or greater and four had a unilateral occlusion of the extracranial internal carotid artery (ICA) (the ICS and ICO groups, respectively). Eight patients had a stenosis of 50% or greater (one bilateral and seven unilateral) (the M1S group). Four patients had unilateral distal occlusion of the horizontal portion of the MCA (the M1O group). Twenty-six patients had no significant extra- or intracranial stenosis on the ipsilateral or contralateral side (the control group). RESULTS: Mean peak-systolic flow velocity on the affected side was 83.0 +/- 20.8 cm/s in the ICS group, 59.8 +/- 23.2 cm/s in the ICO group, and 62.3 +/- 33.7 cm/s in the M1O group. In the control group, the mean peak-systolic flow velocity was 116.0 +/- 31.5 cm/s. In the M1S group, however, the mean peak-systolic flow velocity (334.2 +/- 35.7 cm/s) on the affected side always exceeded 180 cm/s (mean value +/- 2 SD in the control group), and was significantly higher than that in the other groups. The mean peak-systolic flow velocity in the M1S group increased with the grade of stenosis. CONCLUSION: The M1S group members could easily be distinguished from the other group members by their peak-systolic flow velocity in excess of 180 cm/s. Measurement of the peak-systolic flow velocity of the MCA by TCCS may help to identify a significant stenosis in the horizontal portion of the MCA.