Biomedical subjects
Publications and source records attributed to Gunnar Moen.
We report a patient with acute encephalitis of unknown causation who underwent hemicraniectomy because of threatening herniation. The patient recovered uneventfully and three weeks later, findings on neurological examination were normal. Hemicraniectomy should be considered in all patients with encephalitis and threatening herniation.
PURPOSE: To propose an automatic method for estimating voxel-specific arterial input functions (AIFs) in dynamic contrast brain perfusion imaging. MATERIALS AND METHODS: Voxel-specific AIFs were estimated blindly using the theory of homomorphic transformations and complex cepstrum analysis. Wiener filtering was used in the subsequent deconvolution. The method was verified using simulated data and evaluated in 10 healthy adults. RESULTS: Computer simulations accurately estimated differently shaped, normalized AIFs. Simple Wiener filtering resulted in underestimation of flow values. Preliminary in vivo results showed comparable cerebral flow value ratios between gray matter (GM) and white matter (WM) when using blindly estimated voxel-specific AIFs or a single manually selected AIF. Significant differences (P < or = 0.0125) in mean transit time (MTT) and time-to-peak (TTP) in GM compared to WM was seen with the new method. CONCLUSION: Initial results suggest that the proposed method can replace the tedious and difficult task of manually selecting an AIF, while simultaneously providing better differentiation between time-dependent hemodynamic parameters.
BACKGROUND: In recent years, new radiographic diagnostics have increased our knowledge about dissection of the carotid and vertebral arteries as a cause of stroke, probably an underdiagnosed condition. Carotid dissection is now considered one of the most frequent aetiologies of ischaemic stroke in patients less than 50 years of age and it accounts for 20% of all cases under the age of 30. MATERIAL AND METHODS: In this paper we describe clinical course and investigations in four patients who had dissection of the precerebral arteries. RESULTS: Three patients had carotid artery dissection, one vertebral artery dissection. Three patients had ischaemic symptoms. One patient had symptoms following physiotherapy to the neck. INTERPRETATION: Patients with craniocervical arterial dissection should be investigated with ultrasound techniques and MRI or CT; antiplatelet agents or anticoagulation therapy should be considered.
BACKGROUND: The aim of this study was to assess the feasibility, safety, and clinical results in patients treated with intravenous thrombolysis in an acute stroke unit. Results from the first three years with thrombolysis as standard treatment procedure are presented. MATERIAL AND METHODS: All patients admitted to our department within 3 hours after an acute ischaemic stroke were considered for thrombolysis. 33 patients with median age 71 years were treated. RESULTS: 16 patients demonstrated early clinical improvement. Six patients demonstrated a substantial but slow clinical improvement. 11 patients did not improve. One patient developed an intracerebral haematoma and two developed a haemorrhagic infarction without clinical deterioration. At follow-up after six months, 16 patients (49%) had achieved independence [modified Rankin Scale (mRS) 0-2], 12 (36%) had an unfavourable outcome (mRS 3-5). Five patients (15%) died, all within the first 3 months. None died due to a treatment complication. INTERPRETATION: This study suggests that thrombolysis can be administered relatively safely in an acute stroke unit without intensive care facilities. The clinical results and safety were similar to those in large randomized studies and clinical series.
BACKGROUND: Acoustic neuroma is the most common tumour in the cerebello-pontine angle. MATERIAL AND METHODS: We present the results after surgery in 99 cases, and the natural course of the disease in 82 patients followed for up to 20 years (mean 3 years). RESULTS: During the observation period, 43% of the tumours increased in size. 36% of patients suffered increasing hearing loss. Total removal was accomplished in 92 cases. In 12 cases hearing preservation was attempted; successfully in five cases. 72 patients had normal or near normal postoperative facial nerve function, whereas 19 patients got a facial nerve paralysis. Two patients died, one because of haemorrhagic infarction and cerebellar swelling, and one because of ventricular fibrillation. Five patients had to be reoperated for CSF leakage. INTERPRETATION: Acoustic neuroma treatment is still a challenge. We favour a team approach to treat this condition.