No abstract

ObjectiveThere is disagreement over the reliability of technetium Tc 99m (99mTc)-labeled erythrocyte scintigraphy in the localization of active lower gastrointestinal hemorrhage. A previous study at The New York Hospital-Cornell Medical Center that showed a superior sensitivity for localization of scintigraphy versus angiography in surgical patients led the authors to emphasize scintigraphy as the diagnostic test of first choice in the clinical diagnostic algorithm. The authors hypothesized that tagged erythrocyte scintigraphy can be used accurately as the primary diagnostic modality in localizing acute bleeding and guiding surgical intervention. MethodsThe authors conducted a 5-year, retrospective analysis of 224 inpatients who underwent scintigraphic imaging for diagnosis and localization of active lower gastrointestinal bleeding. Using scintigraphy as the primary diagnostic test, with colonoscopy, upper endoscopy, and angiography as adjunctive studies, 99mTc-labeled erythrocyte scans were performed at the clinician's discretion and were reviewed again for study purposes by two nuclear radiologists who were blinded to clinical outcome. Adjunctive diagnostic tests also were ordered for clinical indications. Results

In a patient with primary amyloidosis, we compared T2 values and relative signal intensity ratios of involved organs to those of normal patients. T2 was significantly decreased in the spleen and adrenals, while significantly increased in the pancreas. T2 values were insignificantly changed in the liver, subcutaneous fat, bone marrow, or kidney. Ratios may facilitate detection of relative changes in T2 values.