Search results for "tomography"
showing 10 items of 2332 documents
CT exposure in adult and paediatric patients: a review of the mechanisms of damage, relative dose and consequent possible risks.
2014
An increase has been observed not only in the absolute number of CT examinations but also in the length of coverage and number of scanning phases, with the result that exposure to ionising radiation from CT is becoming an increasingly serious problem. The extent of the problem is not entirely known and cannot be adequately addressed without proper knowledge of all the phases that leads to the effective dose calculation. In light of the growing awareness of the issue of ionising radiation dose and the possible risk for the individual and the population, there is a need for radiologists, medical physicists and radiographers to play an active role in dose management. In this review, the author…
Imaging of sarcopenia.
2016
Sarcopenia is currently considered a geriatric syndrome increasing in older people. The consequences of sarcopenia – in terms of impaired mobility, limited self-sufficiency and disability – have been amply demonstrated, increasing the need to develop methods to identify muscle mass loss as early as possible. Although sarcopenia involves a reduction in both muscle mass and function, loss of muscle mass remains the essential criterion for diagnosing this condition in daily practice. Computed tomography and magnetic resonance imaging represent the gold standard for studying body composition, and can identify quantitative and qualitative changes in muscle mass. These techniques are costly, time…
Sympathetic activity at rest and motor brain areas: FDG-PET study.
2008
Although recent studies identified brain areas which are involved in short term activation of the sympathetic nervous system, little is known about brain mechanisms which generate the individual variability of basal autonomic activity. In this fluorodeoxyglucose positron emission tomography study (FDG-PET), we aimed to identify brain regions, which covary with function parameters of the autonomic nervous system at rest. Therefore, FDG-PET (Siemens, Germany) was performed twice in 14 healthy resting subjects (7 m, 7 f; mean age 29.5 years) while different parameters of autonomic function were assessed simultaneously: Blood pressure, heart rate, power spectra of heart rate variability (HF/LF …
Chimney and periscope grafts to facilitate endovascular treatment of aortic transection in a patient with aberrant right subclavian artery
2014
Purpose: To report the use of parallel grafts to extend the proximal landing zone for stentgraft repair of aortic transection involving an aberrant right subclavian artery (ARSA). Case Report: A 28-year-old patient was referred for treatment of traumatic aortic transection with contained rupture at the level of an ARSA. Immediate thoracic endovascular aortic repair (TEVAR) was planned because of hemodynamic instability. To achieve rapid sealing and maintain perfusion to both subclavian arteries, a chimney stent to the left subclavian artery (LSA) and a periscope stent-graft to the ARSA were deployed successfully. After surgical repair of all fractures, the patient was discharged 1 month aft…
Endovascular Embolization of a Large High-Flow Splenic Arteriovenous Fistula and Aneurysm Using the Amplatzer Vascular Plug II.
2015
We describe the use of an Amplatzer Vascular Plug (AVP) II for embolizing a large high-flow splenic arteriovenous fistula and an aneurysm in a young patient. This patient presented to our center with persistent mild abdominal discomfort, 5 years after open splenectomy. Contrast-enhanced computed tomography angiography showed the presence of a fistula between the splenic arterial and splenic venous remnants and a resultant fusiform aneurysmal dilatation of the residual splenic vein. We decide to embolize the splenic artery with a 12-mm diameter AVP II with an oversizing by 70% of the vessel diameter. Celiac angiography performed 5 min postembolization revealed complete obliteration of the sp…
Involvement of Jugular Valve Insufficiency in Cerebral Venous Air Embolism
2007
Background. Cerebral venous air entrapment is a rare finding on cranial computed tomography (CT) scan. Peripheral air embolism is discussed as a potential cause. However, the mechanism of retrograde passage through internal jugular valves and veins is unclear. Case Report. The case of a patient is reported, who had air entrapment in the left cavernous sinus. Prior to CT scanning, a peripheral intravenous line had been placed. Ultrasound revealed excessive insufficiency of the left internal jugular valve. To further study the mechanism of embolism, an echo contrast agent was injected into the cubital vein. A Valsalva maneuver resulted in retrograde transition of microbubbles across the insuf…
Basilar Artery Occlusion and the Dense Artery Sign in the Newborn
1998
A child with basilar artery occlusion in the neonatal period is reported. The occlusion was documented by unenhanced computed tomography performed in the neonatal period demonstrating a “dense” artery at the tip of the basilar artery. The pattern of cerebral damage on MRI scan at 10 years of age confirmed the site of the vascular occlusion. The evidence suggests that embolization was the operating pathogenic mechanism of cerebral vascular occlusion. Neonatal arterial thrombosis involving the carotid circulation has been well documented and may be due to many pathological factors including direct trauma to the carotid artery and embolization from remote sites. Thrombosis of the vertebral art…
Chromatic and achromatic visual fields in relation to choroidal thickness in patients with high myopia: A pilot study
2018
Purpose. - To analyse the relationship between the choroidal thickness and the visual perception of patients with high myopia but without retinal damage. Methods. - All patients underwent ophthalmic evaluation including a slit lamp examination and dilated ophthalmoscopy, subjective refraction, best corrected visual acuity, axial length, optical coherence tomography, contrast sensitivity function and sensitivity of the visual pathways. Results. - We included eleven eyes of subjects with high myopia. There are statistical correlations between choroidal thickness and almost all the contrast sensitivity values. The sensitivity of magnocellular and koniocellular pathways is the most affected, an…