ABSTRACT
Relatives of people with aneurysmal subarachnoid haemorrhage (SAH) may be at increased risk of SAH, but precise data on the level of risk and which relatives are most likely to be affected are lacking. We studied two samples: 5478 relatives of patients from the whole of Scotland who had a SAH in one year and 3213 relatives of patients with a SAH admitted to the West of Scotland regional neurosurgical unit 10 years previously. Overall, 2% of all relatives in each sample had a SAH. In the Scotland-wide sample, the absolute lifetime risk of SAH (from birth to 70 years) was higher for first-degree relatives [4.7%; 95% confidence interval (CI): 3.1-6.3%] than for second-degree (1.9%; 95% CI: 1.0-2.9%). In the West of Scotland sample, the lifetime risks were very similar to the Scotland-wide sample. The 10-year prospective risk for first-degree relatives alive at the time of the index patient's SAH was 1.2% (95% CI: 0.4-2%) and for second-degree was 0.5% (95% CI: 0.1-0.8%). There was a trend for risk to be highest in families with two first-degree relatives affected and lowest with only one second-degree affected. Most living relatives of patients who suffer a SAH are at low absolute risk of a future haemorrhage; screening is inappropriate except for the few families in whom two or more first-degree relatives, i.e. index case plus one extra have been affected.
Subject(s)
Intracranial Aneurysm/genetics , Subarachnoid Hemorrhage/genetics , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Genetic Predisposition to Disease , Heterozygote , Humans , Incidence , Infant , Intracranial Aneurysm/epidemiology , Male , Middle Aged , Prognosis , Risk Assessment , Scotland/epidemiology , Sex Factors , Subarachnoid Hemorrhage/epidemiology , Survival AnalysisABSTRACT
BACKGROUND AND PURPOSE: Reported CT angiographic (CTA) subtraction methods are not simple, robust, or real time. We investigated a novel technique for semiautomated digital subtraction CTA of the intracranial and extracranial arteries. METHODS: Thirty patients underwent precontrast (low milliampere-seconds) and postcontrast (pitch, 1.5; collimation, 1-2.5 mm) helical imaging with a vacuum-type head holder to facilitate image registration and minimize movement. A reconstructed three-dimensional model of the precontrast bone dataset was subtracted from the postcontrast dataset to produce subtracted maximum-intensity-projection angiograms. Experienced (operator 1) and less-experienced (operator 2) staff performed the standard and subtraction reconstructions, and image generation time and quality (graded 1-5) were compared. A third operator blinded to the method assessed the hard-copy image quality. RESULTS: Image quality with subtraction postprocessing was significantly better with both operators (operator 1, mean improvement of 0.87 grade, median improvement of 1 grade, P <.001; operator 2, mean improvement of 0.63 grade, median improvement of 1 grade, P <.001). Hard-copy image quality was better with the subtraction method (operator 1, P >.001; operator 2, P <.001). Blood vessels at the base of the brain were better demonstrated on subtraction images in 13 of 14 examinations. For the less experienced operator, the reconstruction time was significantly less with the subtraction method than with the conventional method (mean, 7.5 vs 10.1 minutes; P =.001). CONCLUSION: When separation of the vasculature from bone is important and technically difficult, digital subtraction CTA offers a potential advantage. This semiautomated technique is fast and easy to learn, and variably experienced staff can use it.
Subject(s)
Carotid Stenosis/diagnosis , Cerebral Angiography , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Intracranial Aneurysm/diagnosis , Subtraction Technique , Tomography, Spiral Computed , Adult , Aged , Carotid Artery, Internal/pathology , Cerebral Arteries/pathology , Female , Humans , Male , Middle Aged , Observer Variation , Reproducibility of ResultsABSTRACT
Can non-neuroradiologists detect intracranial aneurysms as well as neuroradiologists, using CT and MR angiography? Sixty patients undergoing intra-arterial digital subtraction angiography (IADSA) to detect aneurysms also underwent computed tomographic angiography (CTA) and time-of-flight magnetic resonance angiography (MRA). Consensus review of IADSA by two neuroradiologists was the reference standard. Two neuroradiologists, a neurosurgeon, a neuroradiographer and a general radiologist blinded to IADSA, plain CT and clinical data, independently reviewed hard-copy base and reconstructed maximum intensity projection images of the CTA and MRA studies. Thirty patients had a total of 63 aneurysms, 71.4% were