Two patients with multiple benign and malignant tumors associated with neurofibromatosis underwent radionuclide imaging with Tc-99m DTPA, Tl-201, and Ga-67. In these patients, Tc-99m DTPA accumulated intensively in both the benign and malignant tumors and localized and defined the extent of every tumor. In contrast, Ga-67 and Tl-201 uptake was seen only in focal areas of tumor where there was malignant transformation or at sites that showed progressive tumor growth. Tc-99m DTPA imaging accurately demonstrated areas of neoplastic involvement and identified the areas that would be seen with the other two tracers in individual tumors. Tc-99m DTPA may not always be used for the differential diagnosis of malignant and benign tumors of neurofibromatosis, but it can provide a reference pattern for imaging to evaluate accurately the distribution of Tl-201 and Ga-67 by mapping out the anatomic extent of these tumors.

This paper describes abnormal brain perfusion unexpectedly demonstrated by Tc-99m MAA total-body imaging in two children with intracardiac right-to-left shunt (RLS) associated with complex congenital heart disease. One child was a 12-year-old girl with asplenia cardiac syndrome and multiple cerebral infarctions caused by thromboembolism in the internal carotid artery, and the other child was a 6-month-old boy who developed focal cerebral infarction following shunt operation. In both children, the total-body imaging depicted the brain due to RLS, where radioactivity decreased unilaterally in the cerebral hemisphere. In the first patient, radioactivity also decreased in the contralateral cerebellum, suggesting the crossed cerebellar diaschisis phenomenon. These abnormalities in brain perfusion were confirmed by Tc-99m HMPAO brain SPECT. Careful review of the distribution of the radiotracer in the depicted brain on Tc-99m MAA total-body imaging may provide important information regarding brain perfusion in some patients with a high risk of stroke complication associated with RLS.

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