Universität zu Köln

Reimer, R. P., Flatten, D., Lichtenstein, T., Zopfs, D., Neuhaus, V., Kabbasch, C., Maintz, D., Borggrefe, J. and Hokamp, N. Grosse (2019). Virtual Monoenergetic Images from Spectral Detector CT Enable Radiation Dose Reduction in Unenhanced Cranial CT. Am. J. Neuroradiol., 40 (10). S. 1617 - 1624. DENVILLE: AMER SOC NEURORADIOLOGY. ISSN 1936-959X

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Abstract

BACKGROUND AND PURPOSE: Our aim was to evaluate whether improved gray-white matter differentiation in cranial CT by means of 65-keV virtual monoenergetic images enables a radiation dose reduction compared to conventional images. MATERIALS AND METHODS: One hundred forty consecutive patients undergoing 171 spectral detector CTs of the head between February and November 2017 (56 +/- 19 years of age; male/female ratio, 56%/44%) were retrospectively included. The tube current-time product was reduced during the study period, resulting in 61, 55, and 55 patients being examined with 320, 290, and 260 mAs, respectively. All other scanning parameters were kept identical. The volume CT dose index was recorded. ROIs were placed in gray and white matter on conventional images and copied to identical positions in 65- keV virtual monoenergetic images. The contrast-to-noise ratio was calculated. Two radiologists blinded to the reconstruction technique evaluated image quality on a 5-point Likert-scale. Statistical assessment was performed using ANOVA and Wilcoxon test adjusted for multiple comparisons. RESULTS: The mean volume CT dose index was 55, 49.8, and 44.7 mGy using 320, 290, and 260 mAs, respectively. Irrespective of the volume CT dose index, noise was significantly lower in 65- keV virtual monoenergetic images compared with conventional images (65- keV virtual monoenergetic images/conventional images: extraocular muscle with 49.8 mGy, 3.7 +/- 1.3/5.6 +/- 1.6 HU, P < .001). Noise slightly increased with a reduced radiation dose (eg, extraocular muscle in conventional images: 5.3 +/- 1.4/5.6 +/- 1.6/6.1 +/- 2.1 HU). Overall, the contrast-to-noise ratio in 65- keV virtual monoenergetic images was superior to that in conventional images irrespective of the volume CT dose index (P < .001). Particularly, 65-keV virtual monoenergetic images with 44.7 mGy showed significantly lower noise and a higher contrast-to-noise ratio than conventional images with 55 mGy (P < .001). Subjective analysis confirmed better image quality in 65- keV virtual monoenergetic images, even using 44.7 mGy. CONCLUSIONS: The 65-keV virtual monoenergetic images from spectral detector CT allow radiation dose reduction in cranial CT. While this proof of concept included a radiation dose reduction of 19%, our data suggest that even greater reduction appears achievable.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Reimer, R. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Flatten, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lichtenstein, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zopfs, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Neuhaus, V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kabbasch, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Maintz, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Borggrefe, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hokamp, N. Grosse UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-132562
DOI:	10.3174/ajnr.A6220
Journal or Publication Title:	Am. J. Neuroradiol.
Volume:	40
Number:	10
Page Range:	S. 1617 - 1624
Date:	2019
Publisher:	AMER SOC NEURORADIOLOGY
Place of Publication:	DENVILLE
ISSN:	1936-959X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DUAL-ENERGY CT; COMPUTED-TOMOGRAPHY-ANGIOGRAPHY; ACUTE STROKE; HEAD CT; QUALITY; HEMORRHAGE; DIAGNOSIS; RECONSTRUCTION; COEFFICIENT; IMPROVEMENT Multiple languages Clinical Neurology; Neuroimaging; Radiology, Nuclear Medicine & Medical Imaging Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13256