Search

Background: Although specificity of SPECT/CT examination using technetium-99m radiolabeled red blood cells (Tc-99m-RBC) for detection of liver hemangiomas is very high, it is still not perfect. It is possible to overlook a malignancy. Moreover, the difference in accumulation of RBCs between a hemangioma and uninvolved liver remains unknown. The aim of the study is to determine the quotients of accumulation of Tc-99m-RBC in hemangiomas and in normal liver parenchyma (HEM/liv), and to verify, whether the quotient could be potentially helpful in distinguishing hemangiomas from other RBC-accumulating liver masses., Material/methods: 34 liver lesions larger than 1.5 cm classified scintigraphically (qualitatively) in our Department as either typical or suspicious of hemangioma 1.5-4 years earlier were enrolled in this retrospective study. Their SPECT/CT images were acquired 1 hour after in vivo labeling of RBCs with Tc-99m. In reconstructed images, ellipsoidal regions of interest (ROIs) with diameters of about 1.5 cm were created in the assessed lesions (HEM) and in the uninvolved liver parenchyma (liv). The HEM/liv quotients were calculated for each mass. The results were compared with radiological data., Results: 31 lesions were found to be clinically and radiologically typical for hemangiomas, their HEM/liv ratios were at least 1.6 (smaller masses) or 1.8 (larger masses). One lesion with HEM/liv ratio equal to 1.21 was classified as metastasis. Two lesions with HEM/liv 1.42 and 1.46 were classified as benign foci other than hemangioma., Conclusions: The quantitative analysis can be preliminarily proposed as a helpful tool in the assessment of possible liver hemangiomas.

Aminopeptidase N (APN) is known to play important roles in tumor angiogenesis, tumor cell invasion, and metastasis. Thus, APN is an attractive biomarker for imaging tumor angiogenesis. Here we report results obtained from biodistribution and single photon emission computed tomography (SPECT) imaging studies of a technetium-99m labeled probestin (a potent APN inhibitor) conjugate containing a tripeptide, Asp-DAP-Cys (DAP=2,3-diaminopropionic acid), chelator and a 8-amino-3,6-dioxaoctanoic acid (PEG2) linker conducted in nude mice xenografted with HT-1080 human fibrosarcoma tumors (APN-positive tumors). These results collectively demonstrate that (99m)Tc-probestin uptake by tumors and other APN expressing tissues in vivo is specific and validate the use of probestin as a vector for targeting APN in vivo., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Although FDG PET is increasingly used for the staging of many types of sarcoma, little has been written regarding the FDG PET imaging characteristics of solitary fibrous tumor. We report a patient undergoing FDG PET/CT surveillance for squamous cell carcinoma of the tongue who was incidentally found to have two soft tissue masses in the retroperitoneum and pancreatic tail. Due to their low degree of FDG avidity, they were followed conservatively for approximately one year as they gradually increased in size. Technetium-99m sulfur colloid SPECT helped confirm that the pancreatic tail mass was not a splenule, after which both lesions were surgically resected and found to be extrathoracic solitary fibrous tumors without malignant features. These findings suggest that, as with other low-grade sarcomas, benign extrathoracic solitary fibrous tumors exhibit relatively little glycolytic metabolism in vivo.

Tc-99m labeled RBC scintigraphy is commonly employed in the evaluation of acute gastrointestinal bleeding. On Tc-99m RBC studies gastrointestinal bleeding is seen as an initial focus of increased radiotracer activity that on subsequent images increases in intensity and changes position in a pattern that conforms to segments of bowel. We report a case of a patient with multiple episodes of hematochezia that presented with lower gastrointestinal hemorrhage. A Tc-99m labeled RBC scan was performed and the findings suggested a GI bleed. However, subsequent angiography revealed prominent ileal varices simulating an acute bleed. Although most varices fill promptly and should not be misinterpreted as a focus of hemorrhage, slow filling varices can simulate an acute bleed and lead to a false positive interpretation.

Two novel benzofuran derivatives coupled with (99m)Tc complexes were tested as probes for imaging cerebral β-amyloid plaques using single photon emission tomography. Although both derivatives bound to Aβ(1-42) aggregates, (99m)Tc-BAT-BF showed higher affinity than (99m)Tc-MAMA-BF. In sections of brain tissue from an animal model of AD, (99m)Tc-BAT-BF clearly labeled β-amyloid plaques. In biodistribution experiments using normal mice, (99m)Tc-BAT-BF displayed high uptake soon after its injection and washed out from the brain rapidly, a highly desirable feature for an imaging agent. (99m)Tc-BAT-BF may be a potential probe for imaging β-amyloid plaques in Alzheimer's brains.