Masashi Nagamoto

Evaluation of the acute adverse reaction of contrast medium with high and moderate iodine concentration in patients undergoing computed tomography

PurposeThe aim of this prospective study was to evaluate and compare acute adverse reactions between contrast medium containing moderate and high concentrations of iodine in patients undergoing computed tomography (CT).Materials and methodsA total of 945 patients undergoing enhanced CT were randomly assigned to receive one of two doses of contrast medium. We then prospectively investigated the incidence of adverse reactions. Iopamidol was used as the contrast medium, with a high concentration of 370 mg I/ml and a moderate concentration of 300 mg I/ml. The frequency of adverse reactions, such as pain at the injection site and heat sensation, were determined.ResultsAcute adverse reactions were observed in 2.4% (11/458) of the moderate-concentration group compared to 3.11% (15/482) of the high-concentration group; there was no significant difference in incidence between the two groups. Most adverse reactions were mild, and there was no significant difference in severity. One patient in the high-concentration group was seen to have a moderate adverse reaction. No correlation existed between the incidence of adverse reactions and patient characteristics such as sex, age, weight, flow amount, and flow rate. The incidence of pain was not significantly different between the two groups. In contrast, the incidence of heat sensation was significantly higher in the high-concentration group.ConclusionsThe incidence and severity of acute adverse reactions were not significantly different between the two groups, and there were no severe adverse reactions in either group.

Wandering spleen with gastric volvulus and intestinal non-rotation in an adult male patient

We report an extremely rare case of wandering spleen (WS) complicated with gastric volvulus and intestinal non-rotation in a male adult. A 22-year-old man who had been previously treated for Wilson disease was admitted with severe abdominal pain. Radiological findings showed WS in the midline of the pelvic area. The stomach was mesenteroaxially twisted and intestinal non-rotation was observed. Radiology results did not show any evidence of splenic or gastrointestinal (GI) infarction. Elective emergency laparoscopy confirmed WS and intestinal non-rotation; however, gastric volvulus was not observed. It was suspected that the stomach had untwisted when gastric and laparoscopic tubes were inserted. Surgery is strongly recommended for WS because of the high risk of serious complications; however, some asymptomatic adult patients are still treated conservatively, such as the patient in this study. The present case is reported with reference to the literature.

Development of diffusion-weighted image using a 0.3T open MRI.

The purpose of this study was to develop a new technique for diffusion-weighted MRI (DWI) with a low-field scanner. DWI is becoming important for assessment of acute stroke. Until recently DWI required expensive technology. We developed multishot-DWI sequence for 0.3T open type MR imager. We prospectively studied forty patients on this 0.3T MRI and compared this DWI to single-shot-DWI by 1.5T-MRI. Group A: Twenty-four patients with acute cerebral infarctions detected by 1.5T-DWI were re-examined using 0.3T-DWI within 24 hours. Sixteen patients with acute cerebral infarctions detected by 0.3T-DWI were re-examined using 1.5T-DWI within 24 hours. In 22 (92%) of 24 cases, 0.3T-DWI showed high signal. In the other two patients, motion artifact distorted 0.3T-DWI. Group B: In all 16 patients, all infarctions detected by 0.3T-DWI showed high signal on 1.5T-DWI. These preliminary data show that, as long as the patient is able to keep still, multishot-DWI can be acquired successfully on a 0.3T open type MRI system.

Revisit image control for pediatric chest radiography

PurposeThe aim of this study was to analyze the fraction defectiveness and efficacy of the patient immobilization device (PID) for pediatric chest radiography.Materials and methodsWe examined 840 plain chest radiographs in six hospitals, including four childrens hospitals and two general hospitals. The mean age of the patients was 1.9 years (range 0–5 years). Two board-qualified pediatric radiologists rated (into three grades, by consensus) the degree of inspiration, rotation, lordosis, scoliosis, and cutoff or coning as well as the quality of the chest radiographs.ResultsThe incidence of “poor” and “very poor” quality examinations was 2/140 and 3/140 in each of two childrens hospitals using PID. The corresponding figures were 9/139 and 17/140 in the two childrens hospitals that did not use PID. The general hospital using PID had 14/140 “poor” and “very poor” examinations. The general hospital that did not use PID had 28/140 “poor” and “very poor” examinations. Thus, statistically better quality chest radiography was obtained with the use of PID (P < 0.001). Likewise, rotation, lordosis, and scoliosis were less frequently diagnosed as present when PID was used (P < 0.001, 0.001, 0.05). Cutoff or coning had no relation to the use of PID (P = 0.13). No significant difference was found between the degree of inspiration and the use of PID (P = 0.56).ConclusionFraction defectiveness in the general hospital that did not use PID was as much as 14 times higher than that of the childrens hospitals that used PID. The patient immobilization device is recommended for hospitals with technologists not specifically trained for pediatric examination.

Evaluation of the changes in signals from the spleen using ferucarbotran

PurposeBecause superparamagnetic iron oxide is actively taken into the reticuloendothelial system, the signal intensity observed on T2-weighted images is reduced not only in the liver but also in the spleen. There is no difference in the reduction in signal intensity in the liver after contrast between the ferumoxides and ferucarbotran, but the reduction in signal intensity in the spleen is considerable. In the present study, we examined the efficacy of T2*-weighted imaging to compensate for the reduction in signal intensity in the spleen by administering ferucarbotran.Materials and methodsWe examined the images obtained from 35 patients who underwent MRI with ferucarbotran. T2-weighted images and T2*-weighted images were obtained before and after administration of ferucarbotran, and the changes in signal intensity in the liver and spleen were then analyzed.ResultsA reduction in signal intensity was observed in the liver by both T2- and T2*-weighted imaging. In the spleen, the signal intensity was reduced on T2-weighted images but was not reduced on T2*-weighted images.ConclusionThe reduction in signal intensity due to administration of ferucarbotran is low in the spleen. Thus, it was considered necessary to approach the problem of diagnosing ectopic splenic tissue using ferucarbotran with caution.