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Low‐contrast resolution in volumetric x‐ray CT—Analytical comparison between conventional and spiral CT
Author(s) -
Wang Ge,
Vannier Michael W.
Publication year - 1997
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597905
Subject(s) - imaging phantom , interpolation (computer graphics) , spiral (railway) , image resolution , iterative reconstruction , computed radiography , tomography , image quality , nuclear medicine , standard deviation , contrast to noise ratio , image noise , physics , mathematics , optics , radiology , medicine , computer science , image (mathematics) , artificial intelligence , statistics , motion (physics) , mathematical analysis , classical mechanics
Spiral/helical computed tomography (CT) was introduced to scan an anatomical volume in a single breath‐hold for better temporal resolution as compared to conventional CT. Recently, it was established that given an x‐ray dose, spiral CT also allows better longitudinal high‐contrast resolution due to retrospective reconstruction. In spiral CT, full scan with interpolation (FI) and half‐scan with interpolation (HI) are limited by the degraded slice sensitivity profile and increased image noise, respectively. We combined these two interpolation methods for a desirable balance. This new interpolation method, FI+HI, was shown to produce 4% lower image noise standard deviation than conventional CT, without loss of longitudinal bandwidth according to one‐tenth‐cutoff and mean‐square‐root measures. The analytic model of image noise was validated in a water phantom experiment. Our findings suggest the superiority of spiral CT over conventional CT in terms of both low‐contrast resolution and high‐contrast resolution.