RESUMEN
RATIONALE AND OBJECTIVES: The authors investigate the cerebral effects of selective carotid angiography with carbon dioxide (CO2). METHODS: In 6 pigs, CO2 was injected into the carotid artery with consecutively increasing doses. Cerebral function was monitored with two-channel electroencephalography and somatosensory evoked potentials (SEPs). After the experiment the brains were investigated histopathologically. RESULTS: Initial doses led to reversible decreases in electroencephalograph power by 40% to 80%. Further doses result in partly nonreversible electroencephalographic changes. Somatosensory evoked potential latencies (n = 5) were not changed. Amplitudes were not affected in low dose ranges up to 40 mL CO2. Higher CO2 doses led to different changes. There were no SEP amplitude reductions (n = 1), as well as reversible (n = 2) and nonreversible (n = 2) SEP amplitude reductions. Histopathologically, edema (n = 6), edema necrosis (n = 2), and destroyed cells as a sign of ischemia (n = 2) were found. CONCLUSIONS: Administering CO2 in brain supplying arteries impairs the cerebral function. Consecutive, increasing doses lead to partly nonreversible electroencephalographic and SEP changes and brain tissue damages.
Asunto(s)
Angiografía/métodos , Encéfalo/efectos de los fármacos , Dióxido de Carbono , Arterias Carótidas/diagnóstico por imagen , Electroencefalografía/métodos , Potenciales Evocados Somatosensoriales/efectos de los fármacos , Angiografía/efectos adversos , Animales , Encéfalo/patología , Encéfalo/fisiopatología , Isquemia Encefálica/inducido químicamente , Isquemia Encefálica/patología , Dióxido de Carbono/administración & dosificación , Dióxido de Carbono/efectos adversos , Relación Dosis-Respuesta a Droga , Edema/inducido químicamente , Edema/patología , Electroencefalografía/efectos de los fármacos , Infusiones Intraarteriales , Necrosis , Proyectos Piloto , Porcinos , Porcinos EnanosRESUMEN
Within the last 18 months we examined 130 patients with known complications or contraindications using iodinated contrast media for angiography by using carbon dioxide as contrast agent in digital subtraction angiography technique. These were diagnostic pelvis-leg angiographies (n = 106) with simultaneous consecutive interventional radiologic therapy in 68 cases. In 19 dialysis access fistulas 11 angioplasties were performed in the same session. In 5 cases of renal allografts no interventional radiologic therapy was necessary. For CO2 application an electronic controlled special injector was used. Carbon dioxide has a number of advantages: no adverse reactions, nonallergenic and can be used several times without increasing risks and is cost-saving. CO2 angiography is a sensitive method, for detection vessel wall processes below the diaphragm. It can replace conventional angiography.
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Angiografía de Substracción Digital/instrumentación , Dióxido de Carbono , Medios de Contraste , Radiografía Intervencional/instrumentación , Angioplastia de Balón/instrumentación , Arteriopatías Oclusivas/diagnóstico por imagen , Arteriopatías Oclusivas/terapia , Derivación Arteriovenosa Quirúrgica/instrumentación , Contraindicaciones , Medios de Contraste/efectos adversos , Humanos , Pierna/irrigación sanguínea , Pelvis/irrigación sanguínea , Diálisis Renal , Sensibilidad y Especificidad , StentsRESUMEN
A closed gas pressure pistol was used in 50 patient CO2 angiography as a supplementary method to conventional injection with liquid contrast medium. These were diagnostic pelvis-leg angiographies (n = 36), therapeutic angiographies (n = 8), haemodialysis fistulas (n = 3), suspected stenosis of a renal transplant artery (n = 1) and suspected renal artery stenosis (n = 1). 246 renal angiography series were performed with CO2. Dosages varied in accordance with the imaged vascular area between 10 ccm;(shunt imaging) and up to 100 cm3 (pelvis-leg angiography), at pressures between 400 mbar in case of haemodialysis fistulas up to 2000 mbar in the pelvis-leg area. Short-term feeling of fullness and even nausea were accompanying symptoms in 4 patients. The image quality was slightly inferior to that of conventional contrast medium images due to an elevated signal-to-noise ratio. Injector-monitored CO2 angiographies enabled imaging of the distal aorta or of peripheral vascular sections, imaging of the upper extremity and presentation of kidney transplants in patients with a relative or absolute contraindication to iodised contrast media.
Asunto(s)
Angiografía/métodos , Dióxido de Carbono , Medios de Contraste , Angiografía de Substracción Digital/métodos , Derivación Arteriovenosa Quirúrgica , Dióxido de Carbono/administración & dosificación , Medios de Contraste/administración & dosificación , Estudios de Evaluación como Asunto , Humanos , Trasplante de Riñón , Arteria Renal/diagnóstico por imagen , Obstrucción de la Arteria Renal/diagnóstico por imagen , Diálisis RenalRESUMEN
PURPOSE: In a vascular model the mechanisms of a pulsed dye laser working in a liquid and a gaseous environment was tested and documented by means of a high-speed camera. METHODS: The pulse application (630 nm wavelength) on a target of calcified arterial plaque material was detected at intervals of 20 microseconds up to 800 microseconds total time. RESULTS: In water the laser beam created a cavitation bubble which expanded from 0 to 450 microseconds from a radius 0 to 3 mm and collapsed afterwards. The average expansion velocity of the bubble was 80 m/s in the first 20 microseconds and the resulting velocity of the tube model wall was 10 m/s. Compared with gaseous atmosphere there was no bubble and consecutively no wall stress. CONCLUSION: It is obvious that laser angioplasty causes wall stress and destruction of different vascular layers. This might be the initial stimulation for restenosis. In gaseous atmosphere laser angioplasty should be more protective.
Asunto(s)
Angioplastia por Láser/métodos , Arterias/cirugía , Calcinosis/cirugía , Dióxido de Carbono , Modelos Anatómicos , AguaRESUMEN
A stereotactic device was developed to facilitate CT- or MR-guided punctures of the body. The correct needle angulation is checked by the reflection of fan-shaped red and green laser beams upon the needle. Due to its principle of function and design the device has considerable advantages: The puncture angle can be controlled in three dimensions. The freedom of movement within the operation area will not be affected. The device does not have to be permanently installed and can be employed in MRI at any field strength. Furthermore, all kinds of puncture instruments can be used.
Asunto(s)
Rayos Láser , Imagen por Resonancia Magnética/instrumentación , Punciones/instrumentación , Tomografía Computarizada por Rayos X/instrumentación , Biopsia con Aguja/instrumentación , Drenaje/instrumentación , Diseño de Equipo , Humanos , Modelos Estructurales , Técnicas Estereotáxicas/instrumentaciónRESUMEN
Doppler ultrasound examination as diagnostic device in angiology yields only discontinuous information on flow velocities in vessels during insonation with hand-held probes. Continuous insonation and therefore determination of flow velocities in arteries are necessary to evaluate flow disturbances and changes of flow velocities during radiologic invasive interventions, i.e. implantation of stents, during percutaneous transluminal angioplasty therapy or local lysis. This modification of Doppler ultrasound examination is already used in neurosurgery for permanent monitoring of flow velocities in large brain vessels in one or both hemispheres during therapy. In our institute we developed a probe holder device to fix a miniature Doppler ultrasound probe (8-MHZ pulsed-wave probe) on the skin surface. Therefore continuous insonation during the manipulations is easy to realize. Information about complications such as occlusions, thrombi, emboli and changes in flow velocity is immediately present on the screen. We have monitored 40 patients during radiologic interventional therapy in arteries of the lower limb. Complications during the interventions were detected immediately and could be corrected.