Leveraging non-contrast head CT to improve the image quality of cerebral CT perfusion maps

Radiologic technologists face various types of patients during multi-detector computed tomography (CT) examinations. In emergency departments, it is common to have patients who cannot follow instructions for the examinations. The asymmetric axial view of the head CT might affect the correctness of the clinician’s diagnosis. This study aimed to assess the impact of head positioning on the image quality of head CT using two phantoms. All scans were performed on a 16-slice CT scanner. In the control group, the tilted angle of the phantoms was 0[Formula: see text], and no multiplanar reconstruction (MPR) was performed. In the experimental groups, the tilted angles of the phantoms were 5[Formula: see text], 10[Formula: see text] and 15[Formula: see text], respectively, and MPR was performed afterwards. The results showed that if the head was tilted during the head CT examinations, image asymmetry and artifacts appeared without MPR. After MPR, one phantom showed that there were significant differences and the other phantom showed no significant differences quantitatively in image symmetry and artifacts between experimental groups and the control group, while both phantoms showed no significant differences qualitatively in image symmetry and artifacts between experimental groups and the control group. Although MPR can correct the image asymmetry and artifacts caused by tilted head positioning to some extent, it consumes time. Therefore, technologists should position the head as exactly as possible when performing head CT examinations.

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Total Bolus Extraction Method Improves Arterial Image Quality in Dynamic CTAs Derived from Whole-Brain CTP Data

BioMed Research International ◽

10.1155/2014/603173 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

Elyas Ghariq ◽

Adriënne M. Mendrik ◽

Peter W. A. Willems ◽

Raoul M. S. Joemai ◽

Eidrees Ghariq ◽

...

Keyword(s):

Image Quality ◽

Ct Perfusion ◽

Ct Scanner ◽

Whole Brain ◽

Acute Cerebral Ischemia ◽

Dynamic Ct Angiography ◽

Information Dynamic ◽

Hemodynamic Information ◽

Ophthalmic Arteries

Background and Purposes. The 320-detector row CT scanner enables visualization of whole-brain hemodynamic information (dynamic CT angiography (CTA) derived from CT perfusion scans). However, arterial image quality in dynamic CTA (dCTA) is inferior to arterial image quality in standard CTA. This study evaluates whether the arterial image quality can be improved by using a total bolus extraction (ToBE) method.Materials and Methods. DCTAs of 15 patients, who presented with signs of acute cerebral ischemia, were derived from 320-slice CT perfusion scans using both the standard subtraction method and the proposed ToBE method. Two neurointerventionalists blinded to the scan type scored the arterial image quality on a 5-point scale in the 4D dCTAs in consensus. Arteries were divided into four categories: (I) large extradural, (II) intradural (large, medium, and small), (III) communicating arteries, and (IV) cerebellar and ophthalmic arteries.Results. Quality of extradural and intradural arteries was significantly higher in the ToBE dCTAs than in the standard dCTAs (extraduralP=0.001, large intraduralP<0.001, medium intraduralP<0.001, and small intraduralP<0.001).Conclusion. The 4D dCTAs derived with the total bolus extraction (ToBE) method provide hemodynamic information combined with improved arterial image quality as compared to standard 4D dCTAs.

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Analisis Reduksi Dosis Efektif Mata Pada Fantom Menggunakan TLD Mata dengan Implementasi Software Organ Dose Modulation (ODM) dan Eyeshield pada Protokol CT Kepala dengan Alat GE Revolution Evo 128 Slice

Jurnal Pengawasan Tenaga Nuklir ◽

10.53862/jupeten.v1i1.006 ◽

2021 ◽

Vol 1 (1) ◽

pp. 26-30

Author(s):

Dito Andi Rukmana ◽

◽

Veronika Saron Kamantuh ◽

Bambang Dwinanto ◽

Lutfiana Desy Saputri

Keyword(s):

Image Quality ◽

Ct Scan ◽

Effective Dose ◽

Research Method ◽

Dose Calculation ◽

Organ Dose ◽

Head Ct ◽

Affect Image Quality ◽

Dose Modulation

The eye is one of the sensitive organs that need attention in the head CT-Scan. This study aims to reduce the effective eye dose on a head CT-Scan using ODM (Organ Dose Modulation) software and use eyeshield on the phantom. The study was conducted using a CT-Scan tool GE Revolution Evo 128 Slice. The research method was carried out by placing three pairs of eye TLDs (Hp3 Dosimeters) on the phantom for the three examination configurations, CT-Scan standard (routine) examinations, examinations using ODM software, and examinations using ODM software and eyeshield. The estimated effective dose calculation based on TLD reading for the eye lens on a standard CT-Scan (routine) is 1.29 mSv. Examination with ODM software is 1.03 mSv. Examination with ODM software and eyeshield of 0.9 mSv. Based on the results obtained, a head CT-Scan with ODM software can reduce the dose by 20% from a routine head CT-Scan, and if added with an eyeshield, it can reduce the dose by 30%. The quality of the image produced by implementing ODM software, SNR value decreased from 39 to 35 in the anterior phantom, central and posterior parts remained. However, the change in SNR value is not significant, so it does not change the image quality. Furthermore, the addition of eyeshield does not alter the SNR value, which means that the addition eyeshield does not cause artifacts that affect image quality. Using ODM and eyeshield software is indeed a little more complicated than a routine head CT-Scan. Still, the benefits obtained are pretty significant, reducing the effective dose received by the eye without reducing image quality.

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Iterative Reconstruction in Head CT: Image Quality of Routine and Low-Dose Protocols in Comparison with Standard Filtered Back-Projection

American Journal of Neuroradiology ◽

10.3174/ajnr.a2749 ◽

2011 ◽

Vol 33 (2) ◽

pp. 218-224 ◽

Cited By ~ 96

Author(s):

A. Korn ◽

M. Fenchel ◽

B. Bender ◽

S. Danz ◽

T.K. Hauser ◽

...

Keyword(s):

Image Quality ◽

Iterative Reconstruction ◽

Low Dose ◽

Ct Image ◽

Back Projection ◽

Filtered Back Projection ◽

Head Ct ◽

Ct Image Quality

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A comprehensive assessment of physical image quality of five different scanners for head CT imaging as clinically used at a single hospital centre—A phantom study

PLoS ONE ◽

10.1371/journal.pone.0245374 ◽

2021 ◽

Vol 16 (1) ◽

pp. e0245374

Author(s):

Patrizio Barca ◽

Fabio Paolicchi ◽

Giacomo Aringhieri ◽

Federica Palmas ◽

Daniela Marfisi ◽

...

Keyword(s):

Image Quality ◽

Coefficient Of Variation ◽

Ct Imaging ◽

Comprehensive Assessment ◽

Phantom Study ◽

Noise Power ◽

Head Ct ◽

Acquisition Protocol ◽

Ct Scanners

Nowadays, given the technological advance in CT imaging and increasing heterogeneity in characteristics of CT scanners, a number of CT scanners with different manufacturers/technologies are often installed in a hospital centre and used by various departments. In this phantom study, a comprehensive assessment of image quality of 5 scanners (from 3 manufacturers and with different models) for head CT imaging, as clinically used at a single hospital centre, was hence carried out. Helical and/or sequential acquisitions of the Catphan-504 phantom were performed, using the scanning protocols (CTDIvol range: 54.7–57.5 mGy) employed by the staff of various Radiology/Neuroradiology departments of our institution for routine head examinations. CT image quality for each scanner/acquisition protocol was assessed through noise level, noise power spectrum (NPS), contrast-to-noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD) and non-uniformity index analyses. Noise values ranged from 3.5 HU to 5.7 HU across scanners/acquisition protocols. NPS curves differed in terms of peak position (range: 0.21–0.30 mm-1). A substantial variation of CNR values with scanner/acquisition protocol was observed for different contrast inserts. The coefficient of variation (standard deviation divided by mean value) of CNR values across scanners/acquisition protocols was 18.3%, 31.4%, 34.2%, 30.4% and 30% for teflon, delrin, LDPE, polystyrene and acrylic insert, respectively. An appreciable difference in MTF curves across scanners/acquisition protocols was revealed, with a coefficient of variation of f50%/f10% of MTF curves across scanners/acquisition protocols of 10.1%/7.4%. A relevant difference in LCD performance of different scanners/acquisition protocols was found. The range of contrast threshold for a typical object size of 3 mm was 3.7–5.8 HU. Moreover, appreciable differences in terms of NUI values (range: 4.1%-8.3%) were found. The analysis of several quality indices showed a non-negligible variability in head CT imaging capabilities across different scanners/acquisition protocols. This highlights the importance of a physical in-depth characterization of image quality for each CT scanner as clinically used, in order to optimize CT imaging procedures.

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Effect of spineboard and headblocks on the image quality of head CT scans

Emergency Radiology ◽

10.1007/s10140-016-1396-z ◽

2016 ◽

Vol 23 (3) ◽

pp. 263-268 ◽

Cited By ~ 5

Author(s):

Baukje Hemmes ◽

Cécile R. L. P. N. Jeukens ◽

Aliaa Al-Haidari ◽

Paul A. M. Hofman ◽

Ed S. vd Linden ◽

...

Keyword(s):

Image Quality ◽

Ct Scans ◽

Head Ct

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Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064189 ◽

1971 ◽

Vol 29 ◽

pp. 26-27

Author(s):

K. Shibatomi ◽

T. Yamanoto ◽

H. Koike

Keyword(s):

Electron Microscope ◽

Image Quality ◽

Scanning Electron Microscope ◽

Chromatic Aberration ◽

Image Contrast ◽

Objective Lens ◽

Thick Specimen ◽

Transmission Electron ◽

Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

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