Age-Dependent Changes in Effective Dose in Pediatric Brain CT: Comparisons of Estimation Methods.

The effective dose (ED) in computed tomography (CT) may be calculated by multiplying the dose-length product (DLP) by a conversion factor. As children grow, automatic exposure control increases the DLP, while the conversion factor decreases; these two changes affect the ED in opposite ways. The aim of this study was to investigate the methods of ED estimation according to age in pediatric brain CT. We retrospectively analyzed 980 brain CT scans performed for various clinical indications in children. The conversion factor at each age, in integer years, was determined based on the values at 0, 1, 5, and 10 years provided by the International Commission on Radiological Protection (ICRP), using a curve (curve method) or lines (linear method). In the simple method, the ED was estimated using the ICRP conversion factor for the closest age. We also analyzed the ED estimated by a radiation dose management system. Although the median DLP at each age increased with age, the median ED estimated by the curve method was highest at 0 years, decreased with age, and then plateaued at 9 years. The linear method yielded mildly different results, especially at 2 and 3 years. The ED estimated by the simple method or the radiation dose management system showed inconsistent, up-and-down changes with age. In conclusion, the ED in pediatric brain CT decreases with age despite increased DLP. Determination of the conversion factor at each age using a curve is expected to contribute to estimating the ED in pediatric CT according to age.

Successful treatment of acquired uterine arterial venous malformation using N-butyl-2-cyanoacrylate under balloon occlusion.

We present two cases of acquired uterine arterial venous malformation (AVM) which was diagnosed because of massive genital bleeding successfully treated with transcatheter arterial embolization (TAE), using N-butyl-2-cyanoacrylate (NBCA) under balloon occlusion. Balloon occlusion at the uterine artery was performed in both patients for diffuse distribution of NBCA in multiple feeding branches, as well as to the pseudoaneurysm, and for the prevention of NBCA reflux. In one of our patients, balloon occlusion of the draining vein was simultaneously performed to prevent NBCA migration through accompanying high-flow arteriovenous fistula (AVF). Doppler ultrasound at 6 months of both patients documented persistent complete occlusion of AVM. Complete and safe obliteration of acquired uterine AVM was accomplished using NBCA as embolic agent, under balloon occlusion at the communicating vessels of acquired uterine AVM.

Imipenem/cilastatin sodium (IPM/CS) as an embolic agent for transcatheter arterial embolisation: a preliminary clinical study of gastrointestinal bleeding from neoplasms.

PURPOSE: To evaluate the feasibility and usefulness of imipenem/cilastatin sodium (IPM/CS) as an embolic agent for intestinal bleeding from neoplasms. MATERIALS AND METHODS: Seven patients who underwent 11 transarterial embolisations (TAEs) using IPM/CS as an embolic material for duodenal or small/large intestinal tumour bleeding from January 2004 to December 2011 were retrospectively evaluated. A mixture of IPM/CS and contrast medium was introduced through the microcatheter positioned at the feeding artery to the tumour until extravasation disappeared or stasis of blood flow to the tumour staining was observed. RESULTS: Haemostasis was obtained in all patients. Therefore, the technical success rate was 100%. Rebleeding was observed in four patients. All of them underwent repeat TAE using IPM/CS, and haemostasis was obtained successfully. No complication was identified following laboratory and clinical examinations. No haemorrhagic death occurred. Haemorrhagic parameters, including blood haemoglobin and the amount of blood transfusion, improved after TAE. CONCLUSION: The safety, feasibility, and effectiveness of TAE using IPM/CS as an embolic material for intestinal bleeding from neoplasms were suggested by this study. The mild embolic effect of IPM/CS may be adequate for oozing from tumours. Although rebleeding may occur after embolotherapy using IPM/CS, repeat embolisation is effective as treatment for rebleeding.