Kodai Okada

Diagnosis of epidermoid cysts by metrizamide CT cisternography.

SummaryThe authors describe three cases of intracranial epidermoid cysts specifically diagnosed by metrizamide CT cisternography. In CT cisternography of epidermoid cysts, metrizamide enters deep in the tumor clefts and depicts the lobulated margin of the tumor. We consider these findings are specific for this tumor and similar to the findings reported previously in pneumoencephalography or positive contrast cisternography.

Diagnostic Value of CT Cisternography with Intrathecal Metrizamide Enhancement, Comparison with Isotope Cisternography

SummaryMetrizamide CT cisternography (CTC) was performed for the evaluation of CSF dynamics and the diagnosis of skull-base tumors. Results of CTC in 52 cases examined for the study of CSF dynamics correlated well with those of isotope cisternography. However, the degree and duration of ventricular stasis of metrizamide and its transition into a periventricular low-density area in hydrocephalus were recognized more accurately in CTC. Twenty out of 23 cases with suspected skull-base tumor were diagnosed as positive and confirmed by operation. CTC was especially useful in parasellar, CP angle, and other posterior fossa tumors.

Parietal foramina complicated by meningocele.

Parietal foramina are symmetrical bone defects adjacent to the sagittal suture and are not usually associated with other malformations. A case is described in which scalp tumors protruded through the foramina and proved to be meningoceles. No such cases appear to have been previously reported. The possible developmental mechanisms are discussed.

CT Enhancement After Three Hours of Continuous Contrast — Infusion in Acute Stage of Cerebral Infarction

There is general agreement that in stroke victims, enhancement of the infarcted tissue on the computed tomography (CT) image occurs 2–4 weeks after the stroke episode1,8,11,13,15,16. On the other hand, a hypodense mass effect due to brain edema develops within a week of the episode7,10,11, 13,16. Therefore, the question arises whether in human cerebral infarction the blood-brain barrier (BBB) change is an earlier event than is usually accepted3. To obtain a high blood concentration of the contrast medium for a prolonged period of time, we employed long-term continuous infusion of contrast medium rather than the conventional bolus injection, to study CT enhancement during the acute phase of cerebral infarction.

Brain Edema and Eeg During Ischemia and After Restoration of Blood Flow

The present study is aimed towards the following; 1) to elucidate the mechanisms underlying brain edema which develops during ischemia and following the restoration of cerebral blood flow, 2) to analyze the relationship between the degree of brain edema and the duration of temporary ischemia prior to cerebral blood flow restoration, and 3) to correlate the functional recovery of the brain assessed by computer analyzed EEG to the duration of ischemia and to the degree of brain edema.

CT Diagnosis of Brain Tumors

This report is mainly based on experiences of CT in 195 cases of brain tumor, 39 cases of which were examined by sequential delayed enhanced CT. The CT findings of these were compared with those of delayed radioisotope scan, operative and histological findings. The results are as follows. Malignant glioma has usually lower density than normal brain tissue on plain CT, and has a ring or irregular shaped circular high density zone on contrast enhanced CT. The density of cystic or necrotic portion increases gradually and reaches its peak in 3 hours after intravenous contrast media injection (ivcmi). In radioisotope scanning, these tumors show higher uptake in delayed scan than early scan. The density of astrocytoma with large or multiple small cysts is very low on CT, and does not increase on enhanced CT. However, in the case of solid astrocytoma with cyst, the density of cystic area reaches its peak in 3 hours after ivcmi. Meningioma is more sharply delineated than other tumors on CT, and its density becomes homogeneously highest immediately after ivcmi for a short time (30 min.), and then begins to decrease rapidly; in radioisotope scan, early scan reveals higher uptake than delayed scan. Acoustic neurinoma is usually characteristic of its major low density area on plain CT, which takes high density after ivcmi in some cases. In metastatic tumor, a large amount of low density area is detected around the metastatic nodules, and the finding of multiplicity offers considerable evidence of its diagnosis. The increase in density of brain tumor on CT after ivcmi is probably due to its high vascularity and/or increased permeability of vessels in tumor and/or adjacent tissue, and contrast enhancement of cyst in brain tumor is presumably caused by the exudation and/or transudation of contrast media through the cyst wall. In general, the sequential increase and decrease of density of brain tumor on CT after intravenous administration of contrast media is approximate to the sequential change of uptake of radioisotope in tumor on R I scan. We have classified the brain tumor into 4 groups by its sequential pattern of contrast enhancement on CT; immediate, delayed, continuous, and no enhancement.