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Purpose: To evaluate the impact of patient centering and radiation dose during intracranial computed tomography (ICT) on quantitative and qualitative image quality., Materials and Methods: A total of 500 consecutive patients who underwent ICT were retrospectively reviewed using a 128-slice CT scanner (Definition AS+, Siemens, Germany). Patients were subjected in equal numbers to one of two positioning protocols: group A, poorly centered; and group B involved accurate centering before imaging. Gray-white matter (GWM) conspicuity, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) in each group were calculated. Qualitative image quality in terms of GWM differentiation, distinctness of posterior fossa contents, and overall diagnostic acceptability were evaluated by 2 neuroradiologists. The dose length product, CNR, SNR, and noise were measured between each group and data generated were compared using Mann-Whitney U nonparametric statistics. Visual grading characteristic and Kappa analyses were performed., Results: The mean noise index was significantly lower in group B (2.61 ± 0.29) compared with A (2.66 ± 0.21; P < .02). The mean attenuation of GWM, SNR, and CNR in the frontal lobe (A, 1:0.77, 0.84, 8.70 ± 1.36; and B, 1:0.65, 0.85, 15.32 ± 1.21; P < .02), occipital lobe (A, 1:1.10, 1.18, 10.79±2.11; and B, 1:0.94, 0.64, 14.41 ± 3.09; P < .04), and cerebellum (A, 1:0.79, 0.90, 12.56 ± 4.08; and B, 1:0.82, 0.87, 14.07 ± 2.28; P < .04) were significantly higher in group B compared with A, while the globus pallidus, caudate nucleus, and optic track in the basal ganglia demonstrated no difference in each group (P > .05). Mean dose length product demonstrated no significance between each group (A, 1312.03 ± 133.92; B, 1298.11 ± 130.61). The qualitative analyses demonstrated significant increases in visual grading characteristic for each reader (P < .02) and interobserver agreement was significantly increased in protocol B (k = 0.81) compared with A (k = 0.62)., Conclusions: Correct patient centering increases the CNR and SNR in both GWM in the left and right hemispheres of the brain during ICT., (Copyright © 2016 Canadian Association of Medical Radiation Technologists. Published by Elsevier Inc. All rights reserved.)

Multifocal basal ganglia T2-weighted hypointensities are believed to arise mainly from mineralization in and around penetrating arteries and perivascular spaces within gray and white matter structures. Recently, it has been proposed that these hypointensities can serve as a biomarker for small-vessel disease and aging in magnetic resonance imaging when using T2-weighted sequences. With advances in digital coil technology and parameter applications, there has been an increase in image quality and faster examination times. However, artifacts related to higher-field strengths (3.0 T) are reducing image quality. This case report demonstrates reduced focal hypointensities in the basal ganglia by using concentric rectangular blades rotated around the k-space origin to reduce artifacts at 3.0 T., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Increased speeds of computed tomography (CT) acquisition and concomitant increased intravenous (IV) bolus injection rates have placed patients at greater risk of contrast extravasation., Purpose: To assess the efficacy of the MEDRAD XDS extravasation detector by recording the incidence of contrast extravasation in high-risk patients during CT angiography., Material and Methods: We prospectively collected data on 25 adults ages 45 to 85 years (mean=65 years), all of whom were considered to be at high risk of having a contrast extravasation. All patients underwent CT angiography with power-injected IV contrast injection introduced via an antecubital venous line. Details recorded included patient age and weight, contrast volume, flow rate, maximum injector pressure, image quality, and extravasation incidence and volume. The size of the most commonly used cannula was 20 gauge and the flow rates ranged from 4.0 to 6 mL/second., Results: The XDS device alerted the clinicians to five episodes of extravasation. These were identified at an early stage of the injection with no more than 8 mL of contrast material having been introduced., Conclusion: The utility of this device has been demonstrated and its employment should reduce extravasated contrast volumes with minimum discomfort to high-risk patients., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Contrast medium (CM) administration for multidetector computed tomography angiography (CTA) requires using a power injector. Power injectors deliver viscous CM at different flow rates up to a maximum pressure of 300 lb per square inch (psi), provide features that benefit patient safety, improve arterial and parenchymal opacification, and allow flexible and complex injection protocols to be administered. The use of power injectors not only includes contrast but also saline, which is primarily responsible for reducing the overall volume of contrast administration while maintaining peak vessel opacification over a longer duration during the CTA acquisition. CTA faces multiple challenges with advanced scanner hardware. There is an increased need to inject small volumes of CM at fast injection rates over a short duration. This technical overview is to increase the understanding of parameters that influence optimal contrast enhancement and bolus geometry, and to enable the user to modify and optimize scanner and contrast protocols., (Copyright © 2011 Elsevier Inc. All rights reserved.)