title: Enhanced renal image contrast by ethanol fixation in phase-contrast X-ray computed tomography.
abstract: Phase-contrast X-ray imaging using a crystal X-ray interferometer can depict the fine structures of biological objects without the use of a contrast agent. To obtain higher image contrast, fixation techniques have been examined with 100% ethanol and the commonly used 10% formalin, since ethanol causes increased density differences against background due to its physical properties and greater dehydration of soft tissue. Histological comparison was also performed. A phase-contrast X-ray system was used, fitted with a two-crystal X-ray interferometer at 35 keV X-ray energy. Fine structures, including cortex, tubules in the medulla, and the vessels of ethanol-fixed kidney could be visualized more clearly than that of formalin-fixed tissues. In the optical microscopic images, shrinkage of soft tissue and decreased luminal space were observed in ethanol-fixed kidney; and this change was significantly shown in the cortex and outer stripe of the outer medulla. The ethanol fixation technique enhances image contrast by approximately 2.7-3.2 times in the cortex and the outer stripe of the outer medulla; the effect of shrinkage and the physical effect of ethanol cause an increment of approximately 78% and 22%, respectively. Thus, the ethanol-fixation technique enables the image contrast to be enhanced in phase-contrast X-ray imaging.
authors: Graduate School of Medical Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 252-0373, Japan.
authors: Ryota
authors: R
authors: Shirai
authors: Graduate School of Medical Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 252-0373, Japan.
authors: Takuya
authors: T
authors: Kunii
authors: Central Research Laboratory, Hitachi Ltd, 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan.
authors: Akio
authors: A
authors: Yoneyama
authors: Graduate School of Medical Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 252-0373, Japan.
authors: Takahito
authors: T
authors: Ooizumi
authors: Graduate School of Medical Sciences and Allied Health Science, Kitasato University, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 252-0373, Japan.
authors: Hiroko
authors: H
authors: Maruyama
authors: Graduate School of Medical Sciences and Allied Health Science, Kitasato University, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 252-0373, Japan.
authors: Thet Thet
authors: TT
authors: Lwin
authors: High Energy Accelerator Research Organization, 1-1 Ooho, Tsukuba-shi, Ibaraki 305-0801, Japan.
authors: Kazuyuki
authors: K
authors: Hyodo
authors: Graduate School of Medical Sciences and Allied Health Science, Kitasato University, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 252-0373, Japan.
authors: Tohoru
authors: T
authors: Takeda
mesh_terms: D000818:Animals; D000431:Ethanol / Q000737:chemistry*; D005404:Fixatives / Q000737:chemistry; D007668:Kidney / Q000737:chemistry / Q000000981:diagnostic imaging*; D008297:Male; D008858:Microscopy, Phase-Contrast / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods; D016707:Tissue Fixation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D005404:Fixatives; D000431:Ethanol
keywords: crystal X-ray interferometer; ethanol-fixation; kidney; phase shift; phase-contrast X-ray CT