Prospective ECG-triggered axial CT at 140-kV tube voltage improves coronary in-stent restenosis visibility at a lower radiation dose compared with conventional retrospective ECG-gated helical CT.

The purpose of this study was to compare coronary 64-slice CT angiography (CTA) protocols, specifically prospective electrocardiograph (ECG)-triggered and retrospective ECG-gated CT acquisition performed using a tube voltage of 140 kV and 120 kV, regarding intracoronary stent imaging. Coronary artery stents (n = 12) with artificial in-stent restenosis (50% luminal reduction, 40 HU) on a cardiac phantom were examined by CT at heart rates of 50-75 beats per minute (bpm). The subjective visibility of in-stent restenosis was evaluated with a three-point scale (1 clearly visible, 2 visible, and 3 not visible), and artificial lumen narrowing [(inner stent diameter - measured lumen diameter)/inner stent diameter], lumen attenuation increase ratio [(in-stent attenuation - coronary lumen attenuation)/coronary lumen attenuation], and signal-to-noise ratio of in-stent lumen were determined. The effective dose was estimated. The artificial lumen narrowing (mean 43%), the increase of lumen attenuation (mean 46%), and signal-to-noise ratio (mean 7.8) were not different between CT acquisitions (p = 0.12-0.91). However, the visibility scores of in-stent restenosis were different (p < 0.05) between ECG-gated CTA techniques: (a) 140-kV prospective (effective dose 4.6 mSv), 1.6; (b) 120-kV prospective (3.3 mSv), 1.8; (c) 140-kV retrospective (16.4-18.8 mSv), 1.9; and (d) 120-kV retrospective (11.0-13.4 mSv), 1.9. Thus, 140-kV prospective ECG-triggered CTA improves coronary in-stent restenosis visibility at a lower radiation dose compared with retrospective ECG-gated CTA.

Traumatic mesenteric bleeding managed solely with transcatheter embolization.

We report a rare case of mesenteric bleeding following blunt abdominal trauma successfully treated solely with transcatheter arterial embolization (TAE) of the right colic marginal artery. A 56-year-old woman presented with mesenteric bleeding after being involved in a car accident. Computed tomography (CT) showed a large mesenteric hematoma and hemoperitoneum with no associated major injuries to other organs. There was a pseudoaneurysm with extravasation inside the hematoma. TAE was attempted to control bleeding during the preparation for surgical laparotomy. A superior mesenteric angiogram revealed a right colic marginal artery pseudoaneurysm. After successful TAE with microcoils, the affected colon perfusion was preserved via collateral circulation from the ileocolic artery. No ischemic gastrointestinal complications have occurred, and laparotomy has not been necessary during the 6 months after TAE. In isolated mesenteric injury cases, TAE may be a reasonable alternative to emergency laparotomy.

[Patient skin dose in interventional radiology using radiochromic dosimetry film].

Various types of X-ray examinations are currently being carried out for the purpose of diagnosis. However, since dose limits for contamination by medical examinations have not been set, management of dose measurements and contamination records is called for. With increasing use of the IVR technique, reports of radiation injury and the symptoms associated with it have become more common. To advance our understanding of this situation and to reduce contamination, it is necessary to carry out contamination management. The reflection film on which colors are formed by irradiating X-rays has recently come into use. Dose measurement is possible with the use of this film, and, because effective results can be obtained as a result of performing fundamental examinations, the film actually provides dose measurements for the IVR technique. Another benefit is that maximum patient skin dose and dose distribution can be determined in addition to dose measurement. Moreover, since various methods were examined in this study, the method of dose evaluation is also reported for those wishing to employ it in the clinical setting.