[A combined protocol using CT, CT perfusion and CT angiography for the evaluation of cerebral ischemia]

Computed tomography (CT) is a widely available, rapid and readily accessible technique for imaging of the brain by means of which other disorders, such as haemorrhage, can be excluded in patients with the signs of an acute cerebral infarction. Recently, CT perfusion and CT angiography have become available for this clinical application. These investigations can be performed in the same session as conventional CT, without significant delay. A combined CT protocol provides information on both cerebral perfusion and the patency of the extra- and intracranial arteries and can therefore yield valuable additional information in the diagnostic work-up and treatment of patients with acute cerebral ischaemia. Current and future research will have to determine the definitive value of these techniques in clinical practice.

Early posttraumatic subarachnoid hemorrhage due to dissecting aneurysms in three children

Subarachnoid hemorrhage (SAH) due to a ruptured saccular aneurysm is uncommon in children. Pediatric traumatic aneurysms have been reported relatively frequently, tending to bleed after an interval of weeks after head injury. The authors describe three children with acute SAH after head injury caused by intracranial dissecting aneurysms. When head trauma in children is complicated by SAH in basal cisterns, dissecting aneurysms should be considered and treated, because rebleeding may occur.

Proton MRS imaging in the follow-up of patients with suspected low-grade gliomas

We compared the value of changes in proton magnetic resonance spectroscopic imaging ((1)H-MRSI) with changes in clinical status and/or contrast-enhanced magnetic resonance imaging (MRI) in the monitoring of patients with suspected low-grade glioma (LGG). From June 1, 1999 till May 31, 2002, we included consecutive, neurologically intact adult patients suspected of having an LGG, demonstrating non-enhancing supratentorial lesions without edema or mass effect on MRI, and in whom all treatment (including a diagnostic biopsy) was deferred. Till January 1, 2003, patients were surveyed clinically and radiologically (contrast-enhanced MRI and (1)H-MRSI). Patients who showed progression on clinical examination and/or MRI were denoted as progressive disease. Other patients were denoted as stable disease. A decrease in NAA/CHO ratio of > or =20% compared to the baseline value was considered as indicative for progression on (1)H-MRSI. We included 14 patients with suspected LGG. Seven patients demonstrated progressive disease during the follow-up period, preceded or accompanied by concomitant (1)H-MRSI changes in five patients. Four of these five patients were operated on within the follow-up interval. The histological diagnosis demonstrated high-grade glioma in three and LGG in one patient. In the other two patients with progressive disease, no progression was found on (1)H-MRSI. The other seven patients demonstrated stable disease, but four of them showed progression on (1)H-MRSI. Our data do not show convincing evidence that (1)H-MRSI contributes to adequate monitoring and follow-up of patients with suspected LGG. Future research should preferably include pathological data at the time of (1)H-MRSI changes.

Clinical evaluation of stereotactic brain biopsies with an MKM-mounted instrument holder

OBJECT

The aim of this study was to assess the clinical usefulness and accuracy of robot-assisted frameless stereotactic brain biopsies with a recently introduced MKM-mounted instrument holder.

METHODS

Twenty-three patients with intracranial lesions participated in this study. Depending on the size of the intracranial lesion, fiducials for image-to-patient co-ordinate transformation consisted either of bone screws or adhesive markers. Shortly after surgery, postoperative MRI-imaging was performed to demonstrate the location of the biopsy site. These images were compared with the preoperative images to assess the biopsy localisation error.

RESULTS

Postoperative biopsy sites could be demonstrated in six patients with bone screws and in 14 with adhesive markers. These two subgroups yielded average biopsy localisation errors of 3.3 mm (SD 1.7 mm) and 4.5 mm (SD 2.0 mm) respectively. This difference was not statistically significant. One biopsy was located in a liquefied haematoma. All others yielded pathological tissue. There were two postoperative haemorrhages, of which only one was temporarily symptomatic. There was no mortality in the first 30 days after surgery.

CONCLUSIONS

Robot-assisted frameless point-stereotactic techniques represent an alternative to frame-based techniques for the performance of stereotactic biopsies.

Acute headache as a presenting symptom of tacrolimus encephalopathy

A 24 year old woman presented with a sudden excruciating headache mimicking an acute vascular event. She had undergone a lung transplantation because of cystic fibrosis and was receiving maintenance treatment with tacrolimus and prednisone. Ancillary investigation excluded vascular causes. Magnetic resonance imaging demonstrated hyperintense lesions in the infratentorial and parieto-occipital regions consistent with posterior leucencephalopathy syndrome. Both her clinical condition improved and the lesions disappeared completely after withdrawal of tacrolimus, suggesting that her condition could be explained by a tacrolimus encephalopathy.

Classification of thoracic and lumbar spine fractures: problems of reproducibility. A study of 53 patients using CT and MRI

Reproducibility of fracture classification systems in general has been a matter of controversy. The reproducibility of spinal fracture classifications has not been sufficiently studied. We studied the inter-observer and intra-observer reproducibility of the Magerl (AO) classification using radiograms, CTs and MRIs of 53 patients. We compared this classification with the older and simpler Denis classification. Five observers classified the fractures, first using the radiograms and CTs and, 6 weeks later, with radiograms and MRIs. Three of the observers repeated the readings after 3 months. Three observers also classified the fractures according to Denis. Agreement was measured using Cohen's kappa test. The type (A, B, C) classification of the AO system was fairly reproducible with CTs. With MRI this was only moderate. Group subclassification of the types yielded higher kappa values, corresponding to substantial agreement. The agreement was, in general, better with the Denis classification, but the variance was higher due to the difficulty of finding proper categories for some injury patterns. Although the AO classification allows proper registration of all kinds of injury, the reproducibility, especially at the type level, is problematic. Use of MRI and better definition of the distinctive properties of the three different types may enhance the reproducibility of the scheme.

Prenatal exposure to famine and brain morphology in schizophrenia

OBJECTIVE

The authors assessed the effects of nutritional deficiency during the first trimester of pregnancy on brain morphology in patients with schizophrenia.

METHOD

Nine schizophrenic patients and nine healthy comparison subjects exposed during the first trimester of gestation to the Dutch Hunger Winter were evaluated with magnetic resonance brain imaging, as were nine schizophrenic patients and nine healthy subjects who were not prenatally exposed to the famine.

RESULTS

Prenatal famine exposure in patients with schizophrenia was associated with decreased intracranial volume. Prenatal Hunger Winter exposure alone was related to an increase in brain abnormalities, predominantly white matter hyperintensities.

CONCLUSIONS

Nutritional deficiency during the first trimester of gestation resulted in an increase in clinical brain abnormalities and was associated with aberrant early brain development in patients with schizophrenia. Stunted brain development secondary to factors that affect brain growth during the first trimester of gestation may thus be a potential risk factor for developing schizophrenia.