Costs of magnetic resonance imaging services in public hospitals.

Audited cost data from two public hospital installations participating in a trial of the utilisation and efficacy of magnetic resonance imaging are presented. The data cover the period July 1987 to June 1988 when both installations had attained stable patterns of operation. One hospital operated a superconductive system and the other a resistive magnetic resonance imaging unit. Depreciation and salaries represented the major components of cost.

Examination of the nephrographic potential of iotrol by computed tomography.

The x-ray attenuation of the renal cortex of dogs, as determined by computed tomographic (CT) scanning, was measured over a three-day period after an intravenous bolus of 600 mg I/kg of iotrol or iopamidol. A slightly higher density observed 24 hours after injection of iotrol was not considered significant, and was not considered sufficient to warrant clinical application of iotrol for specific, prolonged renal enhancement.

Comparison of blood-brain barrier disruption by intracarotid iopamidol and methylglucamine iothalamate.

Using a canine model, the effect of intracarotid injections of the ionic contrast medium methylglucamine iothalamate was compared with that of the nonionic contrast medium iopamidol of similar iodine concentration (280 mg 1/ml). The degree and distribution of blood-brain barrier disruption was assessed using Evans blue stain as a visual marker and by contrast enhancement measured by a computed tomographic (CT) scanner. In all studies with methylglucamine iothalamate, Evans blue staining was demonstrated, and CT enhancement demonstrated a significant mean difference (p less than 0.01) between the control and injected hemispheres. The absence of blood-brain barrier disruption with iopamidol is probably related to its lower osmolality (570 mosmol/kg) compared with methylglucamine iothalamate (1,424 mosmol/kg) and the absence of any cation.

Brain parenchyma penetration by intrathecal ionic and nonionic contrast media.

Metrizamide, a nonionic water-soluble contrast medium, has been shown to penetrate normal brain when injected intrathecally. Recently it was suggested that the complications following intrathecal metrizamide are directly related to the cerebral concentration reached. Metrizamide, both in experimental animals and clinically, is regarded as less neurotoxic than equivalent iodine concentrations of ionic contrast media. In this study the degree and depth of brain penetration of intrathecal metrizamide and methylglucamine iothalamate (Conray 280), using a similar iodine concentration (280 mg l/ml), was compared at 1 hr in adult greyhound dogs. The depth of penetration and concentration reached in the cortical gray matter was determined by coronal computed tomographic scanning of the brain after removal. No significant difference was found between the two contrast media, suggesting that the rate of diffusion across the cerebrospinal fluid-brain interface is similar and that the difference in neurotoxicity is not explained by a reduced concentration of contrast medium in the case of nonionic metrizamide, when compared with ionic methylglucamine iothalamate. Using Evans blue as a qualitative marker, no evidence of gross blood-brain disruption was demonstrated in the area of maximum penetration with either contrast medium.

Comparison and evaluation of osmotic blood-brain barrier disruption following intracarotid mannitol and methylglucamine iothalamate.

The effect of intracarotid injections of methylglucamine iothalamate has been compared with that of mannitol solution of similar osmotic strength. The degree and distribution of blood-brain barrier disruption was assessed using Evans' Blue dye as a visual marker and by contrast enhancement measured by computer tomography (CT) scanner. Evans' Blue staining was found to match CT enhancement closely. It was also found that methylglucamine iothalamate injections resulted in significantly greater blood-brain barrier permeability. The relevance of these findings to chemotherapy of brain tumours is discussed briefly.

Lumbar myelography today. Experience with metrizamide, a water-soluble, non-ionic contrast medium.

A clinical assessment of metrizamide (Amipaque) lumbar myelography in 150 patients is reported, and the adverse reactions encountered are presented and discussed. Minor adverse reactions--headache (48%), nausea (10%) and vomiting (7%)--were common, and the incidence reflected overseas experience. Severe headache occurred in a significant proportion of patients (20%), despite adequate hydration and the use of a small-gauge needle. There were no major adverse reactions such as epilepsy or severe muscle spasm. The study suggests that metrizamide is well tolerated, gives good anatomical demonstration and should replace iophendylate (Myodil) in this region. Recent reports of occasional, but sometimes severe, neurological complications indicate that further cautious assessment is required.

Diagnostic and therapeutic impact of computerized tomography in patients with malignant brain tumours: South Australian experience.

The incidence of malignant brain tumours in the South Australian population has been determined for two six-months periods before and after the introduction of computerized tomography (CT). The impact of CT on diagnosis and short-term patient status has been analysed in patients with astrocytoma or glioblastoma multiforme. CT has significantly altered neuroradiological practice in these patients, but appears to have had little impact on prognosis or outcome.

Comparison of iopamidol, ioxaglate, and diatrizoate during coronary arteriography in dogs.

Iopamidol and ioxaglate are two new contrast media which have an osmolality approximately half that of diatrizoate for the same iodine concentration. These three contrast media were compared with each other and with Hartmann's solution during coronary arteriography in dogs using hemodynamic and electrocardiographic parameters in addition to coronary venous sinus sampling to measure changes in osmolality, electrolyte, and contrast media concentration. Iopamidol and ioxaglate had similar, but less toxic, effects in comparison with diatrizoate. These new contrast media may offer a reduction in the morbidity and mortality of coronary arteriography.