RESUMEN
Introduction: Radiation exposure is one of the major limitations of computed tomographic coronary angiography [CTA]. The purpose of this study was to compare the objective and subjective image quality and radiation dose using prospective ECG gating [PGA] versus ECG-controlled tube current modulation [ECTCM] scanning techniques. A prospective, single-center study was performed at Prince Sultan Cardiac Centre, Qassim, Saudi Arabia. A total of 104 patients with low-to- intermediate probability of coronary artery disease [CAD] underwent CTA with either PGA or ECTCM acquisition. PGA was performed during the study period and compared with the last 50 CTAs previously done using ECTCM. A 4-point scale was used to assess the image quality subjectively. Objective image quality was assessed using image signal, noise, and signal-to-noise ratio [SNR].Patient's Baseline characteristics were not different between the two scanning protocols. The 4-point score of subjective image quality showed no significant differences between the PGA and ECTCM scans [2.9 +/- 0.7, 2.96 +/- 0.7, respectively; p = 0.87]. The objective image quality showed significantly higher noise and lower SNR with PGA compared with ECTCM [31 +/- 9, 27 +/- 9, respectively; p < 0.001 for noise] and [15 +/- 5, 17 +/- 7, respectively; p < 0.001 for SNR], with no statistical difference in the image signal [434 +/- 123, 425 +/- 103 HU, respectively, p = 0.7]. Radiation exposure was significantly lower with PGA than with ECTCM. The dose-length product [DLP] for PGA was 334 +/- 130 mGy, compared with 822 +/- 286 mGy for the ECTCM. This corresponds to a 59% reduction in radiation exposure [p < 0.0001]. Conclusions: Although prospective ECG-triggered axial scanning increased image noise, it maintained subjective image quality and was associated with a 59% reduction in radiation exposure when compared with ECTCM
RESUMEN
The study was carried in 2004 and 2005. The aim of this study was to establish a protocol for micropropagation of Faucaria tuberculosa plants in vitro. Chlorox and mercuric chloride were used for sterelization treatments. Multiplication of shoots was done by using MS-medium fortified with benzyladenine [BA] or kinetin. Also, full strength Murashige and Skoog [MS] or Wooay plant medium [WPM] with addition of BA, Zeatin or 2iP were studied. Different agar concentrations were added to WPM to promote shoot proliferation and reduce the shoot vitrification. To promote rooting on Faucaria tuberculosa, different strengthes of MS media with or without activated charcoal [AC] were examined. The results showed that the best treatment, to be recommended to obtain free of contamination explants with the highest survival, was by using 40% chlorox with 0.2% mercuric chloride [MC]. Addition of 3 mg/l BA to full strength MS medium produced the highest shootlet number/explant and respectively reduced vitrification of shootlets/explant as compared with 3 mg/l kin in the 3th subculture. No significant differences in shootlets number were found by usingfull strength MS or WPM with 3 mg/l BA, Zeatin or 2iP, while addition of 3 MM BA to full strength WPM reduced vitrificated shootlets/explant. Increasing agar concentration from 7 to 11 g/l in WPM gradually reduced shootlet number and vitrificated shootlet/ explant. 1n rooting stage, using full strength MS medium with 1 g/l activated charcoal increased rooting percentage and root length, while for root number no significant differences could be observed In acclimatization of plantlets, all treatments gave 100% survival