E. B. Ringelstein

OBJECTIVES: Ultrasound of the brain supplying arteries is a standard diagnostic procedure in patients with suspected and definite acute and chronic cerebrovascular occlusive disease. Anatomical and pathological limitations led to the development of echocontrast agents which are able to survive pulmonary and capillary transit and improve the echogenicity of the flowing blood. MATERIAL AND METHODS: This article reviews present and future applications of echocontrast agents in conjunction with personal experiences. RESULTS: Currently, echocontrast is used for the differentiation of internal carotid artery occlusion and pseudoocclusion, better delineation of the maximal narrowing in high-grade stenoses, and better visualization of the extracranial vertebral artery and its collaterals. Transcranial applications include the insufficient foraminal or temporal window, assessment of arteriovenous malformations, thrombosis of cerebral veins and sinuses, and intracranial aneurysms. The use of echocontrast can have direct diagnostic and therapeutic consequences. Harmonic imaging, perfusion imaging, stimulated acoustic emission, and drug delivery are possible future domains of the technique. DISCUSSION: Besides the support of conventional neurovascular ultrasound in poor examination conditions due to the patients' anatomy or pathology, echocontrast agents may allow for novel applications in the diagnosis and treatment of cerebrovascular patients.

<b>Background:</b> Juvenile myoclonic epilepsy (JME) is a syndrome of idiopathic generalized epilepsy (IGE) without structural brain abnormalities detectable by MRI or CT. <b>Objective:</b> In the present study, we addressed the question of whether diffusion tensor MRI (DTI) can detect disease-specific white matter (WM) abnormalities in patients with JME. <b>Methods:</b> We performed whole head DTI at 3 T in 10 patients with JME, 8 age-matched patients with cryptogenic partial epilepsy (CPE), and 67 age-matched healthy volunteers. Nerve fiber integrity was compared between the groups on the basis of optimized voxel-by-voxel statistics of fractional anisotropy (FA) maps obtained by DTI (analysis of covariance, categorical factor “group,” covariate “age”). <b>Results:</b> FA was reduced in a WM region associated with the anterior thalamus and prefrontal cortex in patients with JME compared to both control subjects and patients with CPE (<i>p</i> &lt; 0.001). The patients with CPE showed normal values in this particular WM region. The FA reductions in the patients with JME correlated with the frequency of generalized tonic-clonic seizures (Spearman R = 0.54, <i>p</i> = 0.05). No significant correlations were found in the JME sample between FA reduction and the duration of antiepileptic medication. <b>Conclusions:</b> The results support the hypothesis that juvenile myoclonic epilepsy is associated with abnormalities of the thalamocortical network that can be detected by diffusion tensor MRI. <b>CPE</b> = cryptogenic partial epilepsy; <b>DTI</b> = diffusion tensor imaging; <b>EPI</b> = echoplanar imaging; <b>FA</b> = fractional anisotropy; <b>GMC</b> = gray matter concentration; <b>GTCS</b> = generalized tonic-clonic seizures; <b>IGE</b> = idiopathic generalized epilepsy; <b>JME</b> = juvenile myoclonic epilepsy; <b>MNI</b> = Montreal Neurological Institute; <b>ROI</b> = region of interest; <b>VBM</b> = voxel based morphometry; <b>WM</b> = white matter.

OBJECTIVE: To assess the interaction of cerebral amyloid angiopathy (CAA) and arterial hypertension as cofactors for intracerebral hemorrhage (ICH). METHODS: The authors investigated 129 postmortem brains of hypertensive patients with and without ICH. Sixty-four patients had had deep (n = 40) or lobar (n = 24) ICH. Sixty-five patients without ICH served as controls. Established risk factors for ICH (age, gender, severity of hypertension, bleeding disorders, intake of anticoagulants, and chronic alcoholism) were identified from medical records. Four specimens per brain were stained with hematoxylin-eosin and Congo red. The entire ICH cohort and subgroups were compared with controls using single-factor and multiple logistic regression analyses. RESULTS: CAA was found in 15 of 64 subjects (23%) with ICH and in five of 65 controls (8%; p = 0.026). In single-factor analysis, CAA was more prevalent in lobar ICH compared with controls (p = 0.007) but not in deep ICH. Poor control of hypertension was more prevalent in the entire ICH group (p = 0.01) and in deep ICH (p = 0.016) but not in lobar ICH. ICH was predictive of the presence of CAA (odds ratio: 5.6, 95% CI: 1.8 to 19.5, p = 0.003), and CAA was more likely to be found in lobar ICH in multivariable-adjusted analysis. After adjustment for conventional risk factors, there was a weak association between CAA and deep ICH. CONCLUSION: Cerebral amyloid angiopathy plays a major role in the pathogenesis of intracerebral hemorrhage even in patients with more evident risk factors.

In order to provide a pathogenetically oriented differentiation of brain infarctions on the basis of CT-morphological criteria, the CTs of 422 patients with visible brain infarctions were analysed. All of the supratentorial lesions were classified according to topographical features and were associated with the underlying cardio-vascular and other general diseases. This concept lead to a typology of brain infarctions which allowed for a differentiation of ischaemic lesions due to cerebral microangiopathy on the one hand (i.e. lacunar infarctions, subcortical arteriosclerotic encephalopathy), and lesions due to cerebral macroangiopathy on the other. The latter were hemodynamically induced terminal supply area infarctions and watershed infarctions or territorial infarctions due to thromboembolism. A third group of symmetrical subcortical lesions were associated with hypoxia. The frequencies of cerebral lesions within the whole cohort were as follows: 34% cerebral microangiopathy, 45% macroangiopathy, 1% generalised hypoxia, 10% miscellaneous lesions and 10% non-classifiable infarctions. Stenosing lesions of the extracranial brain supplying arteries were found in 22% of the microangiopathy group but in 71% of the macroangiopathy group. Patients with territorial infarctions presented with embolising extracranial vascular lesions in 42% and with embolising heart disease in 21% of the cases. Local thrombosis of the intracranial large arteries was a rare event. Hypoxia occurred due to haemorrhagic shock, carbon monoxide poisoning, air embolism and strangulation. The following conclusions were drawn: In patients with cerebral microangiopathy any procedures aimed at the diagnosis and therapy of major vessel disease are not useful. Therapy should follow the principles of internal medicine. If haemodynamically induced infarctions are present, the clinician's primary task is to look for high grade extracranial vessel lesions. Recanalizing techniques (endarterectomy and ECIC-bypass) are the main therapeutical strategies. In territorial infarctions the embolising extracranial vessel lesions may be haemodynamically non-significant. An intra-arterial source of emboli should be removed by the vascular surgeon. In younger patients, however, and in patients with normal Doppler findings and/or multiple territorial infarctions, a cardiac source of emboli is highly probable and its diagnosis should be pursued consistently. Bilateral symmetrical ganglionic infarctions are indicative of hypoxia and help to exlude other causes of the severe neurological disturbances associated with this condition.(ABSTRACT TRUNCATED AT 400 WORDS)

Susac syndrome is a rare disease, characterized by the triad of hearing loss, branch retinal artery occlusions, and encephalopathy with predominantly cognitive and psychiatric symptoms.1,2 Focal ischemic lesions in the corpus callosum detectable by conventional MRI are a typical feature of Susac syndrome.3,4 The lesions detectable by conventional MRI do not, however, explain the type and severity of the neuropsychological deficits.5,6 In this study, we tested the hypothesis of whether widespread tissue damage of the otherwise normal-appearing white matter (NAWM) could be detected in patients with Susac syndrome using diffusion tensor imaging (DTI).7 DTI is a noninvasive technique for detection of macro- and microstructural impairment of fiber integrity on the basis of normal values for the fractional anisotropy (FA).8 We hypothesized that the neuropsychological symptoms in patients with Susac syndrome correlated well with the FA aberrations detected with DTI. ### Methods. We investigated four patients with clinically diagnosed Susac syndrome. Their encephalopathic symptoms varied from mild cognitive impairment to severe acute psychosis. The symptoms were dyscalculia, impaired memory, hallucinations, paranoia, disorientation, emotional indifference, and strongly reduced alertness, motivation, concentration and cognitive flexibility. Diagnosis of Susac syndrome was established by the documentation of branch retinal artery occlusions, sensorineural hearing loss, encephalopathy, and the characteristic multifocal snowball-like hyperintense lesions on T2-weighted images (figure 1). In all patients, the diagnosis was based on the typical clinical triad, supported by the detection of the typical white matter (WM) lesions on T2-weighted MRI. Figure 1 T2-weighted images illustrating “snowball” lesions in the corpus callosum of Patients 1 through 4 (A) Patient 1 showed a lesion in the genu of the corpus callosum. (B) “Snowball” lesion in the splenium of the corpus callosum of Patient 2. (C) Patient 3 showed multiple lesions along the corpus callosum. (D) Lesion in the splenium of Patient …