Radiation Doses of Various CT Protocols: a Multicenter Longitudinal Observation Study.

Emerging concerns regarding the hazard from medical radiation including CT examinations has been suggested. The purpose of this study was to observe the longitudinal changes of CT radiation doses of various CT protocols and to estimate the long-term efforts of supervising radiologists to reduce medical radiation. Radiation dose data from 11 representative CT protocols were collected from 12 hospitals. Attending radiologists had collected CT radiation dose data in two time points, 2007 and 2010. They collected the volume CT dose index (CTDIvol) of each phase, number of phases, dose length product (DLP) of each phase, and types of scanned CT machines. From the collected data, total DLP and effective dose (ED) were calculated. CTDIvol, total DLP, and ED of 2007 and 2010 were compared according to CT protocols, CT machine type, and hospital. During the three years, CTDIvol had significantly decreased, except for dynamic CT of the liver. Total DLP and ED were significantly decreased in all 11 protocols. The decrement was more evident in newer CT scanners. However, there was substantial variability of changes of ED during the three years according to hospitals. Although there was variability according to protocols, machines, and hospital, CT radiation doses were decreased during the 3 years. This study showed the effects of decreased CT radiation dose by efforts of radiologists and medical society.

[The usefulness of Doppler sonography in the assessment of disease activity of ulcerative colitis].

BACKGROUND/AIMS: disease activity in ulcerative colitis (UC) is generally assessed using symptoms, laboratory data, endoscopic findings, and histology of the biopsy specimens. In this study, we compared disease activity of UC as determined by clinical features and endoscopic findings, and aimed to assess the clinical usefulness of Doppler sonography. METHODS: the duplex Doppler sonography of superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) of 10 patients with clinically inactive UC and 20 patients with active UC were evaluated by one radiologist who was blinded to clinical information. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), and pulsatility index (PI) of the SMA and IMA were evaluated. All patients underwent biochemical and endoscopic evaluations thereafter. Correlation between disease activity by the Truelove-Witts classification and the Mayo scoring system was measured, and we compared hemodynamic parameters between active and inactive UC. RESULTS: correlation rate of disease activity between these two scoring systems was 93.3%. Flow velocities (PSV, p<0.001 and EDV, p=0.03) and PI (p=0.03) were significantly higher in patients with active UC than inactive UC. PSVs of the SMA and IMA were also significantly correlated with disease severity. The active UC could be accurately diagnosed using Doppler sonography (AUC=0.83; 95% confidence interval 0.68-0.99). CONCLUSIONS: in patients with UC, clinical stage was well matched with endoscopic disease activity. Doppler sonography was a readily available method, and PSV of SMA would be clinically useful in predicting of disease activity and severity.