Jan T. Diehl

Monitoring of methotrexate delivery in patients with malignant brain tumors after osmotic blood-brain barrier disruption.

Reversible transient osmotic blood-brain barrier disruption was used to increase drug delivery to the brain. Methotrexate was administered 33 times to six patients with brain tumors after barrier disruption. No permanent complications were seen. Serial enhanced computed tomographic (CT) scans and quantification by CT tomographic number indicated that disruption increased drug delivery to the tumor and immediate surrounding brain. Neuroradiologic evaluation showed that drug in the tumor persisted longer after barrier disruption than when delivered without disruption. The concentration of methotrexate in spinal fluid did not correlate with the degree of barrier disruption measured by CT and radionuclide scans. In one patient an anatomic variation in the circle of Willis resulted in barrier disruption extending into the posterior fossa without ill effect. Osmotic blood-brain barrier disruption appears to be a safe procedure in man, able to increase drug delivery to both malignant brain tumors and surrounding brain parenchyma.

Subtemporal decompressions for shunt-dependent ventricles: Mechanism of action

The literature suggests that subtemporal decompression is an effective treatment for the syndrome of shunt-dependent ventricles because it allows the ventricle to enlarge around the shunt catheter tip. Pre- and post craniectomy ventricular areas were measured from computed tomography scans with a computer digitizing technique in three patients with this syndrome who had undergone four surgical procedures. All patients improved symptomatically following craniectomy. A significant decrease in total ventricular area was noted in all instances. The results suggest that subtemporal craniectomy causes the ventricles to become smaller, not larger. Other possible explanations for the effectiveness of the procedure are discussed.

Computed tomography in the evaluation of sella and parasella lesions: The value of sagittal and coronal reconstructions

A method is described whereby contiguous, thin-section (3 mm) axial CT scans are obtained followed by computer manipulation of the data to reconstruct good quality images in sagittal and coronal planes. The application of this technique in the evaluation of sella and parasella abnormalities is discussed. In our experience, this has resulted in an increased sensitivity of CT scanning for the detection of abnormalities around the sella. In addition, it has been possible to more accurately define the true extrasella extension of pituitary tumors.

CT scanning in traumatic and emergency patients

In emergency cases and traumatic head cases, CT scanning has completely changed the diagnostic method and angiography can in most cases be avoided. Not only can a proper diagnosis be set concerning intracranial bleedings or hematomas of different kinds but also additional information which earlier with help of angiography were not available can now be diagnosed. The article discusses the principles for using CT scanning as a diagnostic method in traumatic and emergency patients and discusses also the limitations and benefits with this method compared with angiography.

Midline angio-tomography of the posterior fossa

Interpretation of the angiographic findings in posterior fossa angiography can be improved by a simple angiotomographic device which gives a midline tomography of the posterior fossa. Especially the vessels around the brain stem and close to the midline can be well seen and this is especially helpful with lesions in the brain stem and the anterior part of the posterior fossa. A few examples are given of midline angiotomography which demonstrates the advantages of this technique.