Kaj Ericson

Discrepancies in Brain Tumor Extent as Shown by Computed Tomography and Positron Emission Tomography Using [68Ga]EDTA, [11C]Glucose, and [11C]Methionine

A patient with an anaplastic (malignant) astrocytoma was examined with computed tomography (CT) and with positron emission tomography (PET), in the latter case using [68Ga]EDTA, [11C]glucose, and [11C]methionine. The CT examination as well as the [68Ga]EDTA study showed a small tumor located in the region of the head of the left caudate nucleus. The [11C]glucose examination showed increased uptake on the same region, as did the [11C]methionine examination, but the latter also showed a considerable uptake in the entire left thalamic region. The patient died 15 days after the [11C]methionine study and a histologic evaluation of thin sections obtained at autopsy showed excellent agreement between tumor extent and activity distribution after [11C]methionine administration. The tumor tissue seen only with [11C]methionine was histologically different from that part of the tumor observed with the other tracers. Although cytologically similar, the latter showed large necrotic areas and an ability to induce marked endothelial proliferation, whereas in the former neither necroses nor notable endothelial proliferation was seen. In this case more than 50% of the tumor would have remained radiologically imperceptible without the [11C]methionine PET examination.

Capsulotomy for obsessive-compulsive disorder: long-term follow-up of 25 patients.

CONTEXT Capsulotomy is sometimes used as a treatment of last resort in severe and treatment-refractory cases of obsessive-compulsive disorder (OCD). OBJECTIVE To evaluate the long-term efficacy and safety of capsulotomy in OCD. DESIGN Noncontrolled, long-term follow-up trial (mean of 10.9 years after surgery). SETTING University hospital referral center. PATIENTS Twenty-five consecutive patients with OCD who underwent capsulotomy from 1988 to 2000. INTERVENTION Unilateral or bilateral capsulotomy. Lesions were created by means of radiofrequency heating (thermocapsulotomy) or gamma radiation (radiosurgery, gammacapsulotomy). MAIN OUTCOME MEASURE Yale-Brown Obsessive-Compulsive Rating Scale (Y-BOCS) score. RESULTS The mean Y-BOCS score was 34 preoperatively and 18 at long-term follow-up (P < .001). Response (defined as > or = 35% reduction at long-term follow-up compared with baseline) was seen in 12 patients at long-term follow-up. Nine patients were in remission (Y-BOCS score, < 16) at long-term follow-up. Only 3 patients were in remission without adverse effects at long-term follow-up. Response rates did not differ significantly between surgical methods. A mean weight gain of 6 kg was reported in the first postoperative year. Ten patients were considered to have significant problems with executive functioning, apathy, or disinhibition. Six of these 10 patients had received high doses of radiation or had undergone multiple surgical procedures. Results of our magnetic resonance imaging analysis in 11 patients suggest that the OCD symptom reduction may be increased by reducing the lateral extension of the lesions, and a reduction in the medial and posterior extension may limit the risk of adverse effects (ie, smaller lesions may produce better results). CONCLUSIONS Capsulotomy is effective in reducing OCD symptoms. There is a substantial risk of adverse effects, and the risk may vary between surgical methods. Our findings suggest that smaller lesions are safer and that high radiation doses and multiple procedures should be avoided.

A functional cerebral response to frightening visual stimulation

The defense reaction, a fundamental reflex in the human behavioral response to threat, is characterized by anxiety and increased activity of the sympathetic nervous system. To study changes in regional cerebral blood flow (rCBF) related to the defense reaction, volunteers with snake phobia were investigated with positron emission tomography. The relative rCBF during phobogenic visual stimulation was increased in the secondary visual cortex but reduced in the hippocampus, orbitofrontal, prefrontal, temporopolar, and posterior cingulate cortex compared with that observed during neutral visual stimulation. The relative rCBF under aversive stimulation was intermediate between phobic and neutral stimulation. The rCBF patterns observed are suggested to represent a functional cerebral correlate to the visually elicited defense reaction and its associated emotions.

Pet Study of Methionine Accumulation in Glioma and Normal Brain Tissue: Competition with Branched Chain Amino Acids

Five patients with glioma were examined with positron emission tomography using ([11C]methyl)-L-methionine. The study was repeated while the patient was being infused with branched chain amino acids (BCAA), 250 μmol/min. The accumulation rates of methionine in tumor tissue and in normal brain tissue were compared without and with the infusion of amino acids. Both tumor tissue and normal brain tissue showed a reduction in the methionine accumulation by 35% while the patient received the infusion. In one patient with a severe blood-tissue barrier disruption the tumor accumulation rate was unaffected. It is concluded that in gliomas without severe blood-tissue barrier disruption, the accumulation of methionine is governed by processes exhibiting similar properties regarding competition with BCAA as in normal brain tissue.

Sustained attention and awareness of disability in chronic neglect

The possible causative role of defective sustained attention and awareness of disability on the persistence of neglect was explored. The study included stroke patients who had had moderate or severe neglect 1-5 years before the start of the present examination. Questionnaire responses showed that the patients were aware of their disability. Impaired sustained attention was associated with poor performance in two out of three tests most sensitive in detecting neglect. This, together with indications of compensation on neglect tests, is interpreted as providing support for the hypothesis that chronic neglect is related to an impaired sustained attention.

Orbital phlebography in patients with cluster headache

Thirteen patients with cluster headache in an active stage were investigated with orbital phlebography. About 60% of the patients showed pathologic changes on the phlebograms, such as changes in the appearance of the superior ophthalmic vein. Five patients had pathologic changes on both sides and three patients on one side only. All patients with unilateral pathologic findings on orbital phlebography had the attacks on the same side. The phlebographic findings in these patients with cluster headache were very similar to those of patients with the Tolosa-Hunt syndrome. There is also some similarity in the symptoms in the two disorders. It has previously been suggested that the Tolosa-Hunt syndrome is caused by venous vasculitis, and the present findings to some extent support the idea that cluster headache may have the same etiology.

Combined embolization and gamma knife radiosurgery for cerebral arteriovenous malformations

In a study of 46 patients with cerebral arteriovenous malformations (AVMs) the value of combining embolization and gamma knife radiosurgery was assessed. In 35 patients with large grade III to V AVMs (Spetzler-Martin system) staged combined treatment was planned. In 11 patients, radiosurgery complemented embolization for a residual AVM. The number of embolization sessions ranged from 1 to 7 (median 2). Twenty-six patients needed multiple embolization sessions. In 28 patients the grade of AVMs decreased as a result of embolization. In 16 patients collateral feeding vessels developed after embolization which made delineation of the residual nidus difficult. The time lag between the last embolization and radiosurgery ranged from 1 to 24 months (median 4). Nineteen of 35 large grade III to V AVMs were possible to treat by radiosurgery following embolization. In the 46 patients complications occurred in 9 from embolization and in 2 from radiosurgery. Two patients had transient and 9 had permanent neurologic deficits. It is concluded that embolization facilitates radiosurgery for some large AVMs and therefore this combined treatment has a role in the management of AVMs.

CORTICAL BENZODIAZEPINE RECEPTOR BINDING IN PATIENTS WITH GENERALIZED AND PARTIAL EPILEPSY

Summary: Impaired cortical inhibition may be involved in epileptogenic mechanisms. In a positron‐emission tomography (PET) study, we demonstrated a reduction of the cortical benzodiazepine (BZD) receptor density in the epileptic foci of patients with partial epileptic seizures. In the present study, we used the same method in 10 patients with primary generalized epilepsy to determine whether an altered BZD receptor binding could also be demonstrated in this patient group. The [11C]‐labeled BZD receptor antagonist Ro 15–1788 was used as ligand. Receptor affinities and densities were calculated in various cortical regions and then compared with the values from corresponding “nonepileptic” regions in the previously examined partial epilepsy patients. Focal alterations of the BZD receptor density or affinity were not demonstrated in patients with generalized epilepsy. This patient group had a slight tendency toward lower mean cortical BZD receptor density, however, as compared with corresponding values from 10 patients with partial epilepsy. Our results strongly suggest that a focal alteration of cortical inhibition is not a prominent feature of human generalized epilepsy. The observed tendency toward lower mean cortical BZD receptor density may be a consequence of diffusely impaired cortical inhibition. Further investigations of this issue are therefore indicated.

Even the smallest remnant of an avm constitutes a risk of further bleeding

SummaryA case with an ill-defined arteriovenous malformation in the parieto-occipital region is presented. Open surgery was unsuccessful in removing the AVM totally, and treatment with gamma knife radiosurgery was then attempted. At 14 months after this treatment the AVM was believed to be obliterated. The patient had a new intracranial haemorrhage 59 months after radiosurgery. Renewed angiography showed an obvious AVM outside the previously irradiated area. Retrospective analysis of the angiogram at 14 months after radiosurgery revealed early filling of a draining vein as a sign of residual AVM at this time. Renewed radiosurgical treatment was performed. It is believed that an ill-defined margin, laminar flow, and effects of previous surgery might add to difficulties in a proper visualisation and delineation of an AVM. Further, a small remaining shunt may be overlooked if the angiogram is not carefully analysed or if the angiogram is of inferior quality. It should be stressed that partial or almost total obliteration of an AVM is no protection against rebleeding.

The Relationship Between Idiopathic Intracranial Hypertension and Obesity

Objective.— Idiopathic intracranial hypertension (IIH) is usually considered to result from deficient intracranial absorption of cerebrospinal fluid, but has also been suggested to be caused by decreased cranial venous flow because of increased intrathoracic pressure resulting from intra‐abdominal obesity. To test this hypothesis, cerebrospinal fluid pressure (Pcsf), extracranial venous pressure (Pvf), intracranial venous pressure, and body mass index (BMI) were studied in patients with IIH with papilledema compared with patients with chronic tension‐type headache (CTTH).