Erich Hofmann

Silent embolism in diagnostic cerebral angiography and neurointerventional procedures: a prospective study

BACKGROUND Cerebral angiography is associated with a small but definite risk of neurological complications with an unknown incidence of clinically silent embolism. We assessed the neurological complication rate compared with the frequency of silent embolism after angiography METHODS We used diffusion-weighted magnetic resonance imaging (MRI) before and after angiography to assess embolic events. 100 consecutive angiographies (66 diagnostic and 34 interventional procedures) were done on 91 patients. Patients underwent neurological assessment before, immediately after, and 1 day after angiography. FINDINGS Before angiography, no abnormalities were seen on diffusion-weighted MRI. Diffusion-weighted MRI showed 42 bright lesions in 23 patients after 23 procedures (17 diagnostic, six interventional) in a pattern consistent with embolic events. There was no new neurological deficit after any angiographic procedure. After diagnostic angiography in patients with a history of vasculopathy, the frequency of lesions was significantly higher than in patients without vascular risk factors (12 [44%] of 27 vs five [13%] of 39 patients, p=0.03). In diagnostic angiography, the appearance of lesions was significantly correlated with whether vessels were difficult to probe (p=0.01), amount of contrast medium needed (p<0.01), fluoroscopy time (p<0.01), and use of additional catheters (p=0.02). INTERPRETATION After diagnostic and interventional cerebral angiography, embolic events are more frequent than the apparent neurological complication rate. In diagnostic procedures, the incidence of embolism is closely related to a vascular risk profile.

Vulnerability of the nigrostriatal system as detected by transcranial ultrasound

Objective: To assess the incidence of a hyperechogenic substantia nigra (SN) by transcranial sonography (TCS) in healthy people and to evaluate whether an enlarged hyperechogenic SN area is associated with functional impairment of the nigrostriatal system. Background and Methods: Until now, preclinical impairment of the nigrostriatal system could be identified only by functional neuroimaging techniques such as PET in selected groups of patients. TCS is a new, noninvasive ultrasound technique that has demonstrated an increased echogenicity of the SN in patients with PD, whereas in most healthy individuals, the SN is either barely detectable or undetectable by TCS. Results: Of 330 healthy volunteers, 8.6% exhibited an increased echogenicity of the SN. From these, 10 clinically healthy individuals with distinct unilateral or bilateral hyperechogenic signals in the SN region (SN area above 0.25 cm2) underwent comprehensive motor testing, neuropsychological assessment, MRI, and [18F]-dopa PET examination. With regard to motor functions, these individuals did not differ from 10 age- and sex-matched controls with a low echogenic SN and an area of echogenic signals below 0.2 cm2. Enlargement of hyperechogenic areas in the 10 healthy individuals was associated with a marked decrease in the accumulation of [18F]-dopa in the caudate nucleus and putamen. Conclusions: Substantia nigra hyperechogenicity appears to indicate a functional impairment of the nigrostriatal system. Transcranial sonography may be a suitable method of identifying persons at risk of nigrostriatal alterations, making possible the introduction of early neuroprotective therapy.

Arachnoid cysts associated with subdural hematomas and hygromas: analysis of 16 cases, long-term follow-up, and review of the literature.

OBJECTIVE Subdural hematomas and hygromas are infrequently encountered complications of arachnoid cysts of the middle cranial fossa and are particularly rare with cysts of other regions. Reports in the literature focus on casuistic observations. Therapeutic recommendations often include fenestration or extirpation of the cyst wall, in addition to evacuation of the space-occupying lesion. This study evaluates the results of and rationale for a more conservative approach, usually without cyst removal. METHODS Sixteen cases of complicated arachnoid cysts, from a total of 658 patients with subdural hematomas or hygromas, were analyzed retrospectively together with 75 other cases reported in the literature. Additionally, 94 magnetic resonance imaging scans from 89 patients with untreated arachnoid cysts, from a total of 11,487 examinations, were reviewed for signs of hemorrhagic complications. RESULTS Arachnoid cysts of the middle cranial fossa were found in 2.43% of patients with chronic subdural hematomas or hygromas. This indicated a fivefold greater prevalence of arachnoid cysts, compared with our magnetic resonance imaging-examined patient group. Only two patients with untreated cysts showed signs of hemorrhage in magnetic resonance imaging scans. An excellent or good therapeutic result was achieved with evacuation of the subdural fluid by drainage or craniotomy in 13 cases and with conservative treatment in two cases. Only one patient underwent additional fenestration of the cyst wall. No additional symptoms from the arachnoid cysts occurred in a follow-up period of up to 14 years after therapy. CONCLUSIONS We do not generally consider it necessary to perform cyst diversion or fenestration at the time of drainage of a hematoma or hygroma in previously asymptomatic arachnoid cysts.

Cerebral activation patterns in patients with writer's cramp: a functional magnetic resonance imaging study.

Abstract Functional MRI (fMRI), visualizing changes in cerebral blood oxygenation, has to date not been performed either in patients with writers cramp or in healthy subjects during writing. We compared the cerebral and cerebellar activation pattern of 12 patients with writers cramp during writing with a group of 10 healthy subjects performing the same tasks over 30-s periods of rest or writing. Sixty echo planar imaging multi-slice datasets were analysed using SPM96 software. Data were analysed for each subject individually and groupwise for patients vs. controls. Healthy subjects showed a significant activation of the ipsilateral dentate nucleus, contralateral cerebellar hemisphere, contralateral primary sensorimotor cortex, and contralateral precentral gyrus during writing. Patients with writers cramp showed significantly greater activation of the ipsilateral cerebellar hemisphere than controls. Also the activation in the primary sensorimotor cortex extended further caudally and anteriorly towards the premotor association area. Activation was observed in the thalamus during writing only among the patients. Our results indicate an increased basal ganglia output via the thalamus to the motor and premotor cortical areas in dystonia patients and support the notion of disinhibition of the motor cortex leading to coconcentrations and dystonic postures.

Parkinson’s disease and depression: evidence for an alteration of the basal limbic system detected by transcranial sonography

OBJECTIVES Depression is a frequent symptom in Parkinson’s disease. Compelling evidence suggests a role of the brainstem in the control of mood and cognition. In patients with unipolar depression transcranial sonography (TS) studies have shown structural alteration of the mesencephalic brainstem raphe which could suggest an involvement of the basal limbic system in the pathogenesis of primary mood disorders. The objective of the present study was to evaluate whether a similar alteration could be found in depressed patients with Parkinson’s disease using TS. METHODS Thirty patients with Parkinson’s disease and 30 age and sex adjusted controls were examined by TS. Raphe echogenicity was rated semiquantitatively. The severity of motor symptoms and depression was rated using standard research instruments. RESULTS Raphe echogenicity was significantly reduced in depressed patients with Parkinson’s disease compared with non-depressed patients with Parkinson’s disease and control subjects. Raphe echogenicity correlated negatively with degree of motor impairment, and differences in raphe echo between depressed and non-depressed patients with Parkinson’s disease were upheld when motor impairment was controlled for. CONCLUSION These preliminary findings suggest that, as in unipolar depression, a morphological alteration of the brainstem raphe might be involved in the pathogenesis of depression in Parkinson’s disease. This raphe alteration may reflect involvement in the basal limbic system in the pathogenesis of secondary depression. This concept is in line with current knowledge on the pathogenesis of both depression in Parkinson’s disease and primary depressive disorders.

Depression in Parkinson’s disease: brainstem midline alteration on transcranial sonography and magnetic resonance imaging

Abstract Recent studies using transcranial sonography (TCS) have provided evidence of alterations in the mesencephalic midline structures in patients with unipolar depression and depression in Parkinson’s disease (PD), suggesting an involvement of the basal limbic system in primary and secondary mood disorders. This study tested the hypothesis of brainstem midline abnormality in depression and investigated 31 PD patients by magnetic resonance imaging (MRI) and TCS. Signal intensity of the pontine and mesencephalic brainstem midline was rated on T2-weighted images and measured by relaxometry. In addition, two blinded investigators assessed the echogenicity of the brainstem midline by TCS. The severity of motor symptoms and depression were graded independently using standard research scales. Rating of signal intensity and T2 relaxometry of the pontomesencephalic midline structures revealed significant difference between depressed and nondepressed PD patients (P < 0.05). This corresponded to a significant reduction in mesencephalic midline echogenicity of depressed PD patients on TCS images. No correlation was found between raphe signal intensity, T2 relaxation times, or TCS echogenicity and the severity of motor symptoms or depression. This study is the first to show changes in signal intensity and T2 relaxation time of the pontomesencephalic midline structures on MRI in depressed PD patients confirming previous TCS findings. As these midline structures comprise fiber tracts and nuclei of the basal limbic system, the findings may support the hypothesis of an alteration in the basal limbic system in mood disorders.

Is There a Benefit of Preoperative Meningioma Embolization

OBJECTIVETo evaluate the effect of preoperative embolization of meningiomas on surgery and outcomes. METHODSIn a prospective study, 60 consecutive patients with intracranial meningiomas who were treated in two neurosurgical centers were included. In Center A, embolization was performed for none of the patients (n = 30). In Center B, 30 consecutive patients with embolized meningiomas were treated. Preoperatively, tumor size and location, neurological status, and Barthel scale score were recorded. In Center B, the extent of tumor devascularization was evaluated using angiography and postembolization magnetic resonance imaging. Intraoperatively, blood loss, the numbers of blood units transfused, and the observations of the neurosurgeon concerning hemostasis, tumor consistency, and intratumoral necrosis were recorded. Postoperatively, the neurological status and duration of hospitalization were recorded. Six months after surgery, the outcomes were assessed using the Barthel scale and neurological examinations. RESULTSThe mean tumor sizes were 22.9 cc in Center A and 29.6 cc in Center B (P > 0.1). The mean blood losses did not differ significantly (646 ml in Center A versus 636 ml in Center B;P > 0.5). However, for a subgroup of patients with subtotal devascularization (>90% of the tumor) on postembolization magnetic resonance imaging scans in Center B, blood loss was less, compared with the entire group in Center A (P < 0.05). The observations of the neurosurgeon regarding hemostasis, tumor consistency, and intratumoral necrosis did not differ significantly. There were no surgery-related deaths in either center. The rates of surgical morbidity, with permanent neurological worsening, were 20% (n = 6) in Center A and 16% (n = 5) in Center B. There was one permanent neurological deficit (3%) caused by embolization. CONCLUSIONIn this preliminary study, only complete embolization had an effect on blood loss. The value of preoperative embolization for all meningiomas must be reconsidered, especially in view of the high costs and risks of embolization.

The basal ganglia in haemochromatosis.

Abstract Haemochromatosis is characterised by deposition of iron-containing pigment in various organs, but little is known about possible deposition in the brain and its clinical impact. We therefore investigated 14 patients with hereditary haemochromatosis with MRI, CT and transcranial ultrasound (TCS) and examined them neurologically. In six of the patients dense lesions were found within the lentiform nucleus on CT, all of whom displayed hyperechogenic lesions in the same area on TCS, as did one other patient. In these patients the relative signal intensities of the lentiform nucleus measured by MRI relaxometry were higher. No patient had clinical signs of basal ganglia disorders.

Transcranial color-coded real-time sonography in the evaluation of intracranial neoplasms and arteriovenous malformations

Transcranial color-coded real-time sonography (TCCS) was performed in 57 patients with primary intracranial brain tumors (n = 49) or arteriovenous malformations (n = 8) to evaluate its diagnostic potential. In 46 patients (81%), lesions could be identified employing this technique. In 7 patients, transcranial ultrasound examination was not feasible because of bone thickness; in the remaining 4 patients, the tumor was indistinguishable from adjacent brain tissue despite sufficient insonation, suggesting that these neoplasms are isoechogenic. The sonographic features of brain tumors were very similar: a hyperechogenic matrix of the lesion was interspersed by hypoechogenic pixels. Larger hypoechogenic areas (0.5-1 cm) gave evidence of tumor necrosis. Differences between the findings of TCCS and computed tomography concerning tumor size were found in 7 patients, in whom TCCS revealed an area of smaller extension within the corresponding hypodense area on the computed tomographic scan. Perifocal brain edema could not be detected by ultrasound examination. In 13 patients, a thin, hypoechogenic peritumoral halo was disclosed that did not correlate with perifocal brain edema identified by computed tomography and that may have been due to compression of adjacent parenchyma. In patients with arteriovenous malformations, TCCS permitted the identification of the main feeders, the nidus, and the draining venous system by color-coded depiction of intravascular blood flow. In conclusion, TCCS is an additional method for initial diagnosis and highly suitable for follow-up in tumor patients and provides valuable information about tissue characteristics and blood flow.

Do arachnoid cysts grow

SummaryThe volumes of intracranial arachnoit cysts were measured in 136 CT scans of 86 patients. Absolute and relative cyst size was calculated. Left hemisphere and middle cranial fossa location prevailed. A slight negative correlation of relative cyst size with age (r=−0.21, NS) disappeared when analysis was restricted to the adult age group (≥20 years). After the sample was divided into two groups according to relative cyst size (cysts less than mean volume vs cysts greater than mean volume), small AC showed no correlation with age, while large AC correlated positively with age (r=0.79,P<0.05). A subgroup of large AC appears to expand with time, while the majority of small AC remain unchanged.