Katalin Hegedüs

Accuracy of In Vivo Carotid B-Mode Ultrasound Compared With Pathological Analysis Intima-Media Thickening, Lumen Diameter, and Cross-Sectional Area

Background and Purpose— This study aimed to determine the correlation of in vivo ultrasound measurements of intima-media thickening (IMT), lumen diameter, and cross-sectional area of the common carotid artery (CCA) with corresponding measurements obtained by gross pathology and histology. Methods— Sixty-six moribund neurological patients (mean age 71 years) underwent B-mode ultrasound of the CCA a few days before death. During autopsy, carotid specimens were removed in toto. Carotid arteries were ligated and cannulated for injection of a hydrophilic embedding material under standardized conditions. The carotid bifurcation was frozen and cut manually in 3-mm cross slices. Digital image analysis was carried out to determine the diameter and the cross-sectional area of the frozen slices of the CCA. IMT was assessed by light microscope. Ultrasonic and planimetric data were compared. Results— Mean measurements of lumen diameter and cross-sectional area were 7.13±1.27 mm and 0.496±0.167 cm2, respectively, by ultrasound, and 7.81±1.45 mm and 0.516±0.194 cm2, respectively, by planimetric analysis of the unfixed redistended carotid arteries (R2=0.389 and 0.497). The mean IMT was 1.005±0.267 mm by ultrasound and 0.67±0.141 mm histologically, resulting in a mean difference of −31%. Conclusions— Transcutaneous B-mode ultrasound provides a reliable approach for in vivo measurements of the cross-sectional area and, less exactly, of the lumen diameter of the CCA. Compared with histological results, in vivo ultrasound measurements of the IMT are systematically larger.

Akinetic mutism associated with bicingular lesions: Clinicopathological and functional anatomical correlates

SummaryThe clinical symptoms and neuropathological findings of three patients suffering from akinetic mutism were summarized. The patients showed almost absolute mutism and immobility and were unable to communicate in any way. The neurological signs varied from case to case. The pathological features common to all of the cases were bilateral lesions of the rostral part of the anterior cingulate gyri which overlapped onto the neighboring supplementary motor area, while differing as regards other damage. With the help of more recent neurobiochemical findings we tried to analyze the pathomechanism of akinetic mutism on the basis of the structures damaged. There seems to be an anatomic correspondence between the mesolimbocortical dopaminergic system and the circumscribed bilateral lesions of the medial prefrontal cortex. The study suggests that damage of the mesolimbocortical dopaminergic terminal fields in the anteromedial frontal cortex is essential for this specific type of akinetic mutism.

Ectasia of the basilar artery with special reference to possible pathogenesis

The pattern of reticular fibers and some other microscopic features of all the major intracranial arteries were examined in two patients with ectatic basilar artery. In order to make a comparison possible the major cerebral arteries of 105 individuals with advanced atherosclerosis were also investigated. This series includes 40 patients with berry aneurysms. Defects in the elastic lamina and reticular fiber deficiency in the muscular layer were common pathologic features in patients with ectatic basilar artery and in those with berry aneurysm. In the ectatic basilar arteries these alterations were much more conspicuous. In the other atherosclerotic arteries sampled from patients having no malformations, the density of reticular fibers in the media was preserved. It is concluded that atherosclerosis may not have a basic role in the pathogenesis of arterial ectasias, but the severe reticular fiber deficiency in the media associated with extensive defects in the elastic lamina forms the morphologic basis of ectasias. Furthermore, the arterial ectasias and berry aneurysms are most probably different manifestations of the same underlying disorder.

Some observations on reticular fibers in the media of the major cerebral arteries: A Comparative Study of Patients without Vascular Diseases and Those with Ruptured Berry Aneurysms

In spite of the large number of papers about the changes in the cerebral arterial wall occurring under various conditions, no systematic study can be found in the literature on the reticular fibers surrounding the smooth muscle cells of the media. The histologic examination of the major cerebral arteries of 70 individuals without vascular diseases revealed a dense network of fine reticular fibers in the media showing a rather uniform distribution. This pattern did not change significantly from birth up to the age of 50 years and was independent of intimal proliferation with aging. Contrary to this, all the major cerebral arteries of 35 patients who died from rupture of berry aneurysms under the age of 50 contained a considerably smaller amount of reticular fibers, predominantly in the outer part of the media. It is concluded that people having few reticular fibers in their arterial wall are susceptible to develop aneurysms, and the partial lack of these fibers may play an important role in the development of cerebral aneurysms.

A new model for inducing transient cerebral ischemia and subsequent reperfusion in rabbits without craniectomy.

An artificial ball removable by an attached fiber was injected into the middle cerebral artery (MCA) of 16 rabbits, allowing the study of transient (5, 10, 15, or 30 minutes) cerebral ischemia without craniectomy. Measurements of available oxygen (aO2) in the ischemic core (the ventral part of the temporal area) followed by histologic examination verified the embolization. Electroencephalographic power spectra and steady (direct current) potentials were recorded bilaterally on the convexity remote from the actual lesion but still supplied by the MCA. Local cerebral blood flow and aO2 in the border zone between the anterior cerebral artery and the occluded MCA were measured. Embolization caused typical ischemic changes ipsilaterally and alterations characteristic of diaschisis contralaterally. Extreme border zone hyperemia developed without significant aO2 changes in the same region. Restoration of circulation via the circle of Willis induced gradual normalization. Our model for controlled embolization and recirculation proved suitable for detailed studies of the complex changes in brain function caused by transient ischemia.

Reticular fiber deficiency in the intracranial arteries of patients with dissecting aneurysm and review of the possible pathogenesis of previously reported cases

SummaryThe pattern of reticular fibers in the tunica media of the major intracranial arteries was investigated in two patients with dissecting aneurysm. In numerous circumscribed areas, the reticular fibers were absent close to the internal elastic lamina in all major arteries of each patient. It is suggested that the subintimal deficiency in reticular fibers results in insufficient fixing of the tunica intima to the media contributing to their separation when the internal elastic lamina becomes defective. The presumed etiologies of the previously reported cases are reviewed and the possible origin of the deficiency in reticular fibers is discussed.

Dissecting intracranial aneurysm

SummaryA case of spontaneous dissecting aneurysm of the right internal carotid and middle cerebral arteries is presented in a 13-year-old boy. The pathogenetic factors incriminated in previously reported cases are reviewed and the pathological findings are discussed. The abnormalities of the internal elastic lamina as seen in this patient have been observed in numerous cases of intracranial dissecting aneurysms. It is concluded that these defects play an important role in the development of dissection.ZusammenfassungEs wird über einen Fall von einem 13jährigen Jungen mit Schlaganfall und spontanem dissezierendem Aneurysma berichtet. Die angenommenen pathogenetischen Faktoren und die pathologischen Befunde der in der Literatur bereits beschriebenen Fälle werden diskutiert. Die Veränderungen der Lamina elastica interna, die auch in dem vorliegenden Fall gefunden wurden, sind in vielen Fällen der intrakraniellen dissezierenden Aneurysmata beobachtet worden. Aufgrund dieser Beobachtung darf darauf geschlossen werden, daß Schädigung dieser Art eine wichtige Rolle in der Entstehung der Dissektion spielen kann.

Effect of i.v. dipyridamole on cerebral blood flow, blood pressure, plasma adenosine and cAMP levels in rabbits

In response to intravenous administration of dipyridamole, the quantitative and temporal changes in plasma adenosine and cyclic AMP (cAMP) levels in relation to the changes in cerebral blood flow (CBF) and mean arterial blood pressure (MABP) have not been studied. Therefore, we investigated simultaneously the changes in CBF (hydrogen and thermal clearance methods), MABP, plasma adenosine (HPLC) and cAMP (radioimmunoassay) levels for 1 h after intravenous injection of 0.7 and 1.4 mg/kg dipyridamole in rabbits. In separate experiments, only plasma adenosine concentrations were measured to determine how and for how long intravenous administration of 0.7 mg/kg dipyridamole is able to inhibit the removal of plasma adenosine. Dipyridamole decreased MABP, increased plasma adenosine and cAMP levels in a dose-dependent manner. The dose-dependency of increases in CBF could not be demonstrated owing to the marked hypotension. The increase in plasma adenosine concentrations was biphasic. The first peak could be detected at the end of the dipyridamole injection. The second peak occurred 20 min after drug administration, simultaneously with the maximal increases in plasma cAMP level and CBF, whereas the maximal fall in MABP developed earlier. Intravenous administration of 0.7 mg/kg dipyridamole inhibited adenosine uptake only by 25%, which lasted less than 10 min. We concluded that intravenously given dipyridamole is responsible only for the initial short-lasting elevation of plasma adenosine concentration, and is able to induce vasodilation without either dipyridamole itself or adenosine necessarily gaining access to the muscular layer.

Detection of Carotid Artery Stenosis by In Vivo Duplex Ultrasound: Correlation With Planimetric Measurements of the Corresponding Postmortem Specimens

Background and Purpose— The correct detection and quantification of carotid artery disease are of decisive impact on patient prognosis and adequate treatment. In this study, we evaluated the ability of ultrasonography to detect and to grade carotid artery stenosis through a comparison of the in vivo ultrasound findings with the planimetric analysis of the corresponding postmortem specimens. Methods— Shortly before their death, 59 critically ill neurological patients (mean age, 70 years) were prospectively examined by extracranial and intracranial Doppler sonography and color-coded duplex ultrasound. Carotid stenosis was classified by hemodynamic and morphological ultrasound criteria. Carotid specimens were removed in toto during autopsy. Under standardized conditions, specimens were redistended, sectioned, and histologically processed. Computerized planimetric measurements of the arteries were carried out and compared with the ultrasound findings. Correlation of the ultrasound and postmortem planimetric findings was available in 93 carotid bifurcations. Results— Through both techniques, 46 carotid arteries were found to be normal. Steno-occlusive carotid lesions ranged from 8.5% to 100% lumen reduction. Overall, r =0.96 and adjusted R2=0.90. For the steno-occlusive carotid lesions, r =0.91. Conclusions— Extracranial and intracranial Doppler and color-coded duplex ultrasound permits reliable detection and quantification of carotid artery stenoses and occlusions even under difficult examination conditions in critically ill patients.

Burkitt-type lymphoma and reticulum-cell sarcoma. An unusual mixed form of two intracranial primary malignant lymphomas

An unusual mixed type of two primary malignant lymphomas in a 50-year-old woman is reported. The patient had been in good health until 4 months before her death, when she developed epileptic seizures and neurological symptoms attributed to a lesion of the brainstem. Pathologic examination revealed a circumscribed tumor mass in the right parietal lobe, which was shown microscopically to contain two different forms of malignant lymphoma. The histologic features of the peripheral part of the tumor were typical of a Burkitt-type lymphoma, while the central part showed the features of a reticulum-cell sarcoma. The cells of the latter type diffusely infiltrated both temporal lobes, the cerebellum, and the brainstem. It is concluded that in the absence of systemic involvement, the Burkitt-type lymphoma also could be derived from the primitive reticulum cells of perivascular sheaths.