Rare finding of primary aortoduodenal fistula on single-photon emission computed tomography/computed tomography of gastrointestinal bleeding: A case report.

BACKGROUND: Primary aortoduodenal fistula is a rare cause of gastrointestinal (GI) bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive intraluminal hemorrhage. CASE SUMMARY: A 67-year-old man was hospitalized for coffee ground vomiting, tarry stools, and colic abdominal pain. He was repeatedly admitted for active GI bleeding and hypovolemic shock. Intermittent and spontaneously stopped bleeders were undetectable on multiple GI endoscopy, angiography, computed tomography angiography (CTA), capsule endoscopy, and 99mTc-labeled red blood cell (RBC) scans. The patient received supportive treatment and was discharged without signs of rebleeding. Thereafter, he was re-admitted for bleeder identification. Repeated CTA after a bleed revealed a small aortic aneurysm at the renal level contacting the fourth portion of the duodenum. A 99mTc-labeled RBC single-photon emission CT (SPECT)/CT scan performed during bleeding symptoms revealed active bleeding at the duodenal level. According to his clinical symptoms (intermittent massive GI bleeding with hypovolemic shock, dizziness, dark red stool, and bloody vomitus) and the abdominal CTA and 99mTc-labeled RBC SPECT/CT results, we suspected a small aneurysm and an aortoduodenal fistula. Subsequent duodenal excision and duodenojejunal anastomosis were performed. A 7-mm saccular aneurysm arising from the anterior wall of the abdominal aorta near the left renal artery was identified. Percutaneous intravascular stenting of the abdominal aorta was performed and his symptoms improved. CONCLUSION: Our findings suggest that 99mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.

Optimization of alkali fusion process for determination of I-129 in solidified radwastes by neutron activation.

This study determines the optimum temperature for the alkali fusion process used to effectively separate iodine from solidified radwaste attaining low-level 129I by neutron activation. The alkali fusion temperature was adjusted to 120, 200, and 400 °C to approach the optimum conditions associated with a good statistical distribution of the measured 129I data and high chemical recovery yield. Statistical analysis revealed that the optimum temperature of the alkali fusion process was 200 °C, displaying good central tendency and low variance of the measured 129I data, and the respective chemical recovery yields were higher than other temperatures. The optimum fusion condition provides more reliable scaling factors (129I/137Cs) of radwaste.