Magnetic resonance angiography with ultrashort echo times reduces the artefact of aneurysm clips.

We evaluated the ability of an ultrashort echo time (TE) three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequence to reduce the metal artefact of intracranial aneurysm clips and to display adjacent cerebral arteries. In five patients (aged 8-72 years) treated with Elgiloy or Phynox aneurysm clips we prospectively performed a conventional (TE 6.0 ms) and a new ultrashort TE (TE 2.4 ms) 3D TOF MRA. We compared the diameter of the clip-induced susceptibility artefact and the detectability of flow in adjacent vessels. The mean artefact diameter was 22.3+/-6.4 mm (range 14-38 mm) with the ultrashort TE and 27.7+/-6.4 mm (range 19-45 mm) with the conventional MRA ( P<0.0001). This corresponded to a diameter reduction of 19.5+/-9.2%. More parts of adjacent vessels were detected, but with less intense flow signal. The aneurysm dome and neck remained within the area of signal loss and were therefore not displayed. Ultrashort TE MRA is a noninvasive and fast method for improving detection of vessels adjacent to clipped intracranial aneurysms, by reducing clip-induced susceptibility artefact. The method cannot, however, be used to show remnants of the aneurysm neck or sac as a result of imperfect clipping.

Carotid dissection with and without ischemic events: local symptoms and cerebral artery findings.

OBJECTIVE: To study whether spontaneous dissections of the cervical internal carotid artery dissection (ICAD) with and without ischemia of the brain or retina differ in the prevalence of vascular risk factors, local neurologic signs and symptoms, and stenoses and occlusions of the cerebral arteries. METHODS: The authors prospectively studied 181 consecutive patients with 200 ICAD. Diagnosis was based on ultrasonography and MRI or catheter angiography. Vascular risk factors, presenting local (headache, neck pain, Horner syndrome, pulsatile tinnitus, cranial nerve palsy on the side of the ICAD) and ischemic signs and symptoms, and ultrasonographic findings in the carotid and basal cerebral arteries were evaluated. RESULTS: ICAD with ischemic events (n = 145) had a higher prevalence of hypercholesterolemia (p < 0.05), >80% stenoses and occlusions of the ICA (p < 0.0001), and intracranial obstructions (p < 0.001). ICAD without ischemic events (n = 55) had a higher prevalence of Horner syndrome (p < 0.001), cranial nerve palsy (p < 0.01), and normal ICA findings (p < 0.0001). CONCLUSIONS: These data suggest that ICAD causing high-grade stenosis and occlusion are more likely to lead to intracranial obstructions and cerebral or retinal ischemic events. Conversely, ICAD without luminal narrowing cause more local signs and symptoms.

Neuroleptic malignant syndrome during low dosed neuroleptic medication in first-episode psychosis: a case report.

Neuroleptic malignant syndrome (NMS) is a rare but potentially fatal side-effect of antipsychotic drug therapy, especially of dopamine receptor antagonists. As a dose relationship has been postulated, low dose neuroleptization would be expected to help to avoid this side-effect. In contrast, we report on a 21-year-old female following low dose fluphenazine treatment with 2.5 mg/day. The patient recovered from NMS after 3 days of dantrolene administration. Eventually, remission from psychotic symptoms was achieved with clozapine. At 8-month follow-up, psychopathology remained stable and there were no more signs of NMS.

Clinical single-shot diffusion-weighted MRI of the human brain on a short-bore medium-field imager.

Diffusion-weighted MRI (DWI) is becoming important for assessment of acute stroke. Until recently single-shot DWI required expensive technology such as echoplanar imaging (EPI) available only at some research sites. A new medium-field (1.0 T) short-bore MR imager has been developed with which DWI data sets can be acquired. We prospectively studied 169 patients on this 1.0 T commercial system. After conventional imaging, DWI was performed with a single-shot multi-slice sequence with b values 0 an 900 s/mm2, and with the gradients switched in three directions. The apparent diffusion coefficients were calculated with online calculation software. There were 50 patients with totally normal MRI, and 17 had strokes, these strokes were detected as areas of high signal on the images at a maximal b value. There was a drop in the ADC in ischaemic regions: in sub-acute infarcts, the values were between 0.41 and 0.531 x 10(-3) mm2/s. In old infarcts the ADC was 1.15 x 10(-3) mm2/s. Cerebrospinal fluid (CSF) gave low signal whereas areas in the brain had more intermediate intensities (CSF: 3.00; deep white matter: 0.75, cortical grey matter: 0.80, basal ganglia (thalamus): 0.70 and cerebellar white matter: 0.65 x 10(-3) mm2/s. Anisotropy was detected as areas of restricted diffusion along the tracts. These preliminary data show that DWI can be acquired successfully on a medium-field short-bore system. This should allow the technique to be implemented at more sites, therefore facilitating the diagnosis of acute stroke and rendering early intervention feasible.

Relapse and subarachnoid dissemination of a pineal germinoma 14 years after radiation therapy.

Intracranial germinomas are rare tumours which are highly curable with radiotherapy. In recent years treatment with chemotherapy has gained importance. Recurrence and dissemination is seen in about 10-20% of cases within the first 2 years after diagnosis; late recurrence and dissemination is very rare. We describe a patient with a recurrent germinoma 14 years after radiotherapy of a pineal tumour. We further report the management with chemotherapy, the late side effects of radiotherapy and the course of the disease with its fatal dissemination. We conclude that the use of radiotherapy, despite being highly effective, is clearly limited by its late side-effects. New regimens with chemotherapy seem promising but proved to be less effective in our case with tumour seeding throughout the subarachnoid space.

[Diffusion-weighted imaging in acute stroke]. / Diffusionsgewichtete Bildgebung beim akuten Hirnschlag.

Magnetic resonance imaging represents today the most important tool in neuroradiology for both clinical practice and research. MRI allows imaging of the human body in 2 or 3 dimensions with variable tissue contrast. The natural diffusion of tissue protons can now be used as a supplementary contrast mechanism. Different MRI techniques can be used to obtain clinically useful diffusion-weighted images. These techniques all require the use of strong gradient pulses in order to obtain the diffusion contrast. In the current article, the most important physical principles of diffusion measurement are presented. After a short introduction into the basic physical principles, we will present the prerequisites and limitations of clinically relevant applications today. Finally a few select examples of clinical use of these techniques in the acute diagnosis of stroke will be presented.

Local intra-arterial thrombolysis in acute ischemic stroke.

BACKGROUND AND PURPOSE: We performed a retrospective analysis of the prognostic factors in patients treated with local intra-arterial thrombolysis (LIT). The purpose of this study was to evaluate the safety and efficacy of LIT using urokinase in patients with acute ischemic stroke of the anterior or posterior circulation and to determine the influence of clinical and radiological parameters on outcome. METHODS: Forty-three patients were treated with LIT using urokinase (median dose, 0.75x10(6) IU). The median National Institutes of Health Stroke Scale (NIHSS) score at hospital admission was 18 (range, 9 to 36). Nine patients had occlusions of the internal carotid artery (ICA), 23 of the middle cerebral artery (MCA), 1 of the anterior cerebral artery, and 10 of the basilar artery (BA). Outcome was assessed after 3 months and classified as good for Rankin Scale (RS) scores of 0 to 3 and poor for RS scores of 4 or 5 and death. RESULTS: Nine patients (21%) recovered to RS scores 0 or 1, 17 (40%) to scores of 2 or 3, and 7 (16%) to scores of 4 or 5. Ten patients (23%) died. Outcome was good in 17 patients (80%) with MCA occlusions, in 3 patients (33%) with ICA, and in 5 patients (50%) with BA occlusions. Good outcome was associated with an initial NIHSS score of <20 (P<0.001), improvement by 4 or more points on NIHSS score within 24 hours (P=0.001), and vessel recanalization (P=0.02). Recanalization was more likely if LIT was started within 4 hours (P=0.01). Symptomatic cerebral hemorrhage occurred in 2 patients (4.7%). CONCLUSIONS: LIT was most efficacious in patients with MCA and BA occlusions when the initial NIHSS score was less than 20 and when treated within 4 hours. It is of limited value in patients with distal ICA occlusions.

MR angiography with ultrashort echo time in cerebral aneurysms treated with Guglielmi detachable coils.

We evaluated a time-of-flight three-dimensional MR angiographic sequence with an ultrashort echo time for its ability to characterize the perfusional state of cerebral aneurysms that had been treated with Guglielmi detachable coils and to depict adjacent cerebral arteries. The results were compared with findings at conventional MR angiography and digital subtraction angiography. Adjacent vessels were seen better in 36% of patients imaged with the new technique. Both MR angiographic methods detected residual cerebral aneurysmal perfusion with a tendency to overestimate the patent portion of the aneurysm.

Contrast-enhanced transcranial color-coded duplex sonography in ischemic cerebrovascular disease.

BACKGROUND AND PURPOSE: Echo contrast agents have been shown to provide conclusive examinations in most patients with insufficient ultrasound penetration through the temporal bone. We investigated the diagnostic value of contrast-enhanced (CE) transcranial color-coded duplex sonography (TCCD) in patients with ischemic cerebrovascular disease and insufficient temporal windows and evaluated TCCD criteria that predict whether CE-TCCD studies may become conclusive. METHODS: Thirty-three patients presenting with ischemic strokes (n = 21) and transient ischemic attacks (n = 12) were investigated. Extracranial color duplex imaging showed normal findings in 24 patients, eight > or = 70% stenoses and one occlusion of the carotid arteries in 8 patients, and severe occlusive disease of both vertebral arteries in 1 patient. Seven carotid stenoses and vertebral artery obstructions were confirmed by angiography. The galactose/palmitic acid-based echo contrast agent was injected intravenously as bolus of 200, 300, or 400 mg/mL in a dosage of 10, 5, and 5 mL, respectively. RESULTS: Thirty-two of the 33 patients were completely examined because 1 patient who felt pain at the injection site declined further investigations. Twenty-one (66%) of 32 CE studies were conclusive and showed cross-flow through three anterior and two posterior communicating arteries, but no stenoses and occlusions. Precontrast identification of any cerebral artery provided an overall accuracy of 97% in predicting a conclusive CE investigation. Precontrast TCCD identified no arterial Doppler signals in patients with inconclusive CE studies. CONCLUSIONS: CE-TCCD provided conclusive examinations in two thirds of patients with ischemic cerebrovascular disease and ultrasound-refractory temporal windows. Precontrast detection of any cerebral artery reliably predicted a conclusive CE investigation.

Transtemporal power- and frequency-based color-coded duplex sonography of cerebral veins and sinuses.

PURPOSE: To determine the ability of transtemporal power- and frequency-based transcranial color-coded duplex sonography to aid in the assessment of cerebral veins and sinuses, as well as to provide reference data for flow direction and velocity. METHODS: Using a color duplex device equipped with a 2.0/2.5-MHz sector scan, we insonated 120 healthy volunteers and three patients with cerebral venous thrombosis. RESULTS: In subjects 20 to 59 years old, deep middle cerebral veins were identified in 88%, basal veins in 97%, straight sinuses in 60%, and transverse sinuses in 42%. The corresponding values for subjects 60 to 79 years old were 53%, 86%, 23%, and 20%, respectively. Velocities were highest in transverse and straight sinuses, slower in basal veins, and slowest in deep middle cerebral veins. Flow was directed lateromedially in the deep middle cerebral vein, rostrocaudally in the basal vein and straight sinus, and mediolaterally in the transverse sinus. Two patients with straight sinus thromboses showed reversed flow direction in the basal veins, and one patient with superior sagittal sinus thrombosis showed elevated velocities in a deep middle cerebral vein. CONCLUSION: Transtemporal power- and frequency-based color-coded duplex sonography enabled imaging and velocity measurements in deep cerebral veins in subjects 20 to 59 years old, but detection of the straight and transverse sinuses was low. In older subjects, only the basal vein was regularly assessed.

Transoccipital power-based color-coded duplex sonography of cerebral sinuses and veins.

BACKGROUND AND PURPOSE: Power-based transcranial color-coded duplex sonography is a new development for cerebrovascular imaging that is suited for detection of slow velocities. The purpose of this study was to evaluate the ability of this technique to detect cerebral sinuses and veins by means of the occipital window and to provide reference data. METHODS: The straight and inferior sagittal sinuses, great and internal cerebral veins, and basal veins were insonated in 120 normal subjects. The number of identified vessels, peak systolic (PSV) and end-diastolic (PDV) velocities, and resistance indices were determined. RESULTS: In subjects aged 20 to 59 years, straight sinuses were identified in 81% and great and internal cerebral veins in 34%. In subjects aged 60 to 79 years, straight sinuses were detected in 50%, great cerebral veins in 20%, and internal cerebral veins in 13%. All insonated inferior sagittal sinuses and basal veins were missed. Velocities were highest in straight sinuses (PSV, 35 [7 to 64] cm/s; PDV, 23 [2 to 43] cm/s), slower in great cerebral veins (PSV, 23 [12 to 34] cm/s; PDV, 16 [7 to 26] cm/s), and slowest in internal cerebral veins (PSV, 14 [10 to 18] cm/s; PDV, 10 [5 to 15] cm/s) (mean with 95% confidence intervals [CIs]). Straight sinus velocities decreased with age for PSV (20 to 39 years, 40 [7 to 73] cm/s; 60 to 79 years, 28 [9 to 46] cm/s; P < .01) and PDV values (20 to 39 years, 28 [4 to 52] cm/s; 60 to 79 years, 16 [5 to 26] cm/s; P < .001) (mean with 95% CIs) and were higher in women than men in the group aged 20 to 39 years. (P < .05). Resistance indices increased with age in the straight sinus (20 to 39 years, 0.30 [0.18 to 0.42]; 60 to 79 years, 0.42 [0.31 to 0.53]; P < .001) (mean with 95% CIs). CONCLUSIONS: Transoccipital power-based color-coded duplex sonography enabled imaging and velocity measurements in the straight sinus of subjects aged 20 to 59 years. In elder subjects detection rate of the straight sinus decreased, and it was low for deep cerebral veins in all age groups.

Cerebral hemodynamics in subarachnoid hemorrhage evaluated by transcranial Doppler sonography. Part 1. Reliability of flow velocities in clinical management.

During recent years, the management of subarachnoid hemorrhage (SAH) has changed, resulting in an increase in early operations and routine administration of nimodipine. Both influenced the indication for transcranial Doppler sonography (TCD). Furthermore, investigations detected discrepancies between Doppler findings and neurological status. In a prospective study, the reliability of TCD was investigated in patients with SAH treated with intravenously administered nimodipine. Patients with large hematomas were excluded. Neurological deficits immediately after surgery or within the first 48 hours were classified as not delayed, and therefore not necessarily due to vasospasm. The most remarkable points of this study are that there is no significant difference between the flow velocities for Hunt and Hess Grades I and II when compared with those for Grade III, and that Grades IV and V seem to be affiliated with the lowest velocities. When the flow velocities of 11 patients who developed delayed ischemic deficits (DIDs) were compared with those of patients with no deficit, no significant difference was seen. A significant increase in velocity in the days before the onset of DID was found only in 3 of 11 cases. Eight patients showed either constant high or constant low velocities or even, in some cases, decreasing time courses. High flow velocities did not necessarily mean impending neurological deficits: 8 of 66 patients tolerated flow velocities over 200 cm/s. Therefore, it no longer seems to be justified to proclaim that TCD is able to predict neurological deficits, although it is doubtless able to detect vasospasm.(ABSTRACT TRUNCATED AT 250 WORDS)