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Biomedical subjects

T Greitz

Publications and source records attributed to T Greitz.

At least 55 records · Page 3Linked to original sources
PubMed1983

Haemodynamics and oxygen consumption in the dog during high epidural block with special reference to the splanchnic region.

High epidural block (Th I-IV) with bupivacaine was carried out in 16 dogs. Mean arterial blood pressure decreased to 52% of control value owing to nearly equal decreases in systemic vascular resistance and cardiac output. Portal venous blood flow decreased from 25.8 +/- 8.6 to 16.7 +/- 7.2 ml/kg b.w. X min-1 following epidural block, while hepatic arterial blood flow remained unchanged at 9.1 +/- 3.1 ml/kg b.w. X min-1 owing to a reduction in hepatic arterial resistance of 51%. Hepatic oxygen uptake was maintained during the epidural block through increased oxygen extraction. However, total oxygen uptake decreased by 18% and, in spite of this, arteriovenous oxygen content difference increased by 25%, indicating circulatory depression.

Anesthesia, Epidural↗
PubMed1983

Effects of dihydroergotamine on haemodynamics and oxygen consumption in the dog during high epidural block with special reference to the splanchnic region.

Dihydroergotamine (DHE) 0.02 mg X kg-1 was administered i.v. in 9 dogs with high epidural block. Mean arterial blood pressure was restored from 11.0 +/- 2.4 kPa to 18.8 +/- 2.5 kPa by DHE due to a near twofold increase in systemic vascular resistance while cardiac output was unchanged. Hepatic arterial blood flow was reduced by 50% by a marked increase in hepatic arterial resistance above the pre-epidural value, while portal venous blood flow remained unchanged. Hepatic oxygen consumption decreased following DHE in spite of an increase in total oxygen consumption, probably partly due to a reduction in hepatic arterial oxygen availability. The mechanism by which the arterial blood pressure is restored by DHE in dogs during high epidural block must be regarded as unfavourable, especially with respect to the liver.

Anesthesia, Epidural↗
PubMed1983

C-11-labeled glucose and its utilization in positron-emission tomography.

Carbon-11-labeled glucose was prepared photosynthetically using the green alga Scenedesmus obtusiusculus Chod. The carbohydrates were extracted from the cells with dilute HCI and the glucose was isolated and purified using high-performance liquid chromatography. The manipulations in the hot cell are described. Analysis of the material (gas liquid chromatography and HPLC) showed that the glucose obtained was radiochemically pure. The total incorporation of the 11CO2 added to the algae was 60-80%. The radiochemical yield of pure carrier-added glucose was approximately 25%, at 40 min after E.O.B. including the HPLC purification and sterile filtration. The C-11 glucose uptake in rat brain was compared with that of commercial D[U-14C]glucose, and preliminary PET studies with D-[11C]glucose in a patient with a brain infarct are presented.

Animals↗
PubMed1982

Effect of dexamethasone treatment on peritumoral brain edema: evaluation by computed tomography.

In a prospective study, the effect of dexamethasone treatment on brain edema was evaluated by computed tomography (CT) in 14 patients with intracranial neoplasm. A CT study was made immediately prior to the beginning of the treatment and at various intervals for 8 to 19 days thereafter. The volume and attenuation of the edema were measured and related to the time after the start of treatment. In five cases of meningioma, only minor changes were shown; the edema volume either decreased or increased slightly or did not change at all. In four gliomas, a substantial decrease was noted in the edema volume in two cases and a smaller decrease was observed in two cases. In three metastases, a linear decrease in edema volume was noted during the entire follow-up, reducing it to one-fourth of the initial volume after 2 weeks of treatment. In one case of acoustic neuroma and in one undiagnosed lesion, a marked decrease in edema volume was also noted. The attenuation of the remaining edema was constant during the entire treatment time.

Adult↗
PubMed1981

Head fixation device for reproducible position alignment in transmission CT and positron emission tomography.

A head-positioning device allowing accurate position transference between computed tomography and positron emission tomography is described. A base plate is fixed to the patient's head through either an individual mold or screws into the calvarium. This base plate fits onto the headholders of the two devices, thus ensuring that scans are taken at the same level. Using the regular software, the coordinates of an anatomic structure may be determined and transferred between the two images.

Humans↗
PubMed1981

Positron emission tomography with 68Ga-EDTA compared with transmission computed tomography in the evaluation of brain infarcts.

The diagnostic value of positron emission tomography (PET) was evaluated in 41 examinations of 40 patients. 68Ga-EDTA was used as a positron source. The findings were correlated with those of conventional of CT scanning. A clearly pathologic accumulation of 68Ga-EDTA was detected in 29 of 41 PET scans. The precontrast CT scans were negative in 11 and non-conclusive in one patient. CT after administration of contrast medium was performed in 29 patients. Of these, 21 had a clearly pathologic PET scan and 14 had visible contrast enhancement on CT examination. The injury of the blood-brain barrier thus was better demonstrated with PET than with CT. The topologic diagnosis was, however, better demonstrated at CT. It seems that CT and PET are supplementary examinations and that PET is superior to CT in the detection of injury of or absence of the blood-brain barrier.

Adult↗
PubMed1981

CT findings and glucocorticoid receptors in intracranial lesions with edema.

Glucocorticoid receptors were measured in the surgical specimens of 19 intracranial tumors and one brain confusion. None of the patients had received any steroid treatment prior to the operation. Preoperative computed tomography (CT) scans of these patients were evaluated with respect to attenuation values, contrast enhancement, volume of the tumor and edema, and the other characteristics. These various findings were plotted against the amount of glucocorticoid receptors. There was some correlation between the amount of receptor and attenuation as well as contrast enhancement of the tumor. No definite correlation between the volume of edema and/or size of the tumor and the amount of receptor was found in the material taken in its entirety. However, in two tumor groups, namely meningiomas with marked edema and circumscribed, discrete gliomas, a tendency toward a high amount of glucocorticoid receptors was observed. The positive correlation with contrast enhancement, reinforced by reports in the literature that contrast enhancement is affected by steroids, corroborates the theory that the steroid-receptor interaction plays an important role in the vascular permeability of tumors.

Adolescent↗
PubMed1980

Head fixation system for integration of radiodiagnostic and therapeutic procedures.

A head fixation system is described enabling exact transfer of positions between neuroradiological and therapeutic procedures. The key item of the system is a base plate that is rigidly attached to the patient's head, either by a plastic mould or screws onto the calvarium. The base plate may easily and accurately be attached to diagnostic or therapeutic units. Coordinates of target points in the various units are directly related through the exact application of the base plate. Procedures for the exact comparison of spatial information have been worked out. The system has been used for diagnostic procedures such as plain skull radiography, cerebral angiography, CT scanning, position emission tomography, and gamma camera examinations, as well as for therapeutic procedures such as stereotaxic biopsy and radiation treatment.

Head↗
PubMed1980

An approach to stereotaxic radiography.

A simple approach to stereotaxic radiography, including a new method for determination of target coordinates, is described. The proposed technique may be used in combination with conventional equipment for roentgen examinations available in X-ray departments and operating rooms; the only additional outfit needed is a coordinate frame that can be attached to the patient's head. Determination of the coordinates is easily made graphically, or from a simple equation using a pocket calculator or a mini-computer.

Brain↗
PubMed1980

CT localization of stereotactic surgery.

A stereotactic system is described. It is built around a baseplate which is fastened to the head of the patient and to various diagnostic and therapeutic modalities. In principle this system can function as an interface between most diagnostic (CT scanners, PET scanners, conventional X-ray instrumentation for angiograms and pneumoencephalograms) and therapeutic (stereotactic instruments, linear accelerators) instruments. It has been in practical use since 1976 and used in a number of 'diagnostic-therapeutic' combinations.

Biopsy↗
PubMed1980

Stereotaxic computerized tomography with a GE 8800 scanner.

A stereotaxic system is described that uses computerized tomography scanning for target localization. This system is unique in that the sterotaxic localization may be carried out using the scanner computer without the addition of any extra software. The hardware of the system is built up around a base plate which is fastened to the scanner's patient table. The head is positioned and fixed to the base plate with aluminum bars, which are fixed to the calvaria with screws. Various stereotaxic devices may be fastened to the base plate. The system has been in clinical use for 4 months at the time of writing. Its main application has been in tumor biopsies, but it has also been used for functional operations.

Humans↗
PubMed1979

Diagnosis of sellar and parasellar lesions by computed tomography.

Suspected lesions in and around the sella were examined by CT in 129 cases. The diagnostic accuracy and various technical aspects of the method are described. The mean attenuation and enhancement after administration of contrast material are evaluated in craniopharyngiomas, chromophobe adenomas, meningiomas, aneurysms, dermoid cysts, an arachnoid cyst and a glioma. the choice of collimator and its use in relation to sellar dimensions, particularly the sellar depths, are emphasized.

Diagnosis, Differential↗
PubMed1978

Attenuation changes of the ventricular CSF after intravenous injection of contrast material.

The CT attenuation change of the intraventricular CSF after i. v. administration of contrast material has been studied in 20 patients. A very small increase of attenuation was observed in the entire material. The method does not seem to be appropriate at present for the study of small attenuation changes in the CSF reflecting the passage of contrast material.

Adolescent↗