Precise Localization of Occult Gastrointestinal Hemorrhage Using Dynamic SPECT/CT

Incidental Detection of Ectopic Ovary Varices by 99mTc-Red Blood Cell Bleeding Scintigraphy in a Patient With Cirrhosis

ABSTRACT

A 72-year-old woman with cirrhosis underwent a 99mTc-labeled red blood cell (RBC) bleeding scan because of recurrent gastrointestinal bleeding. The images showed abnormal 99mTc-RBC accumulation in a mass in the region of the left ovary. Contrast-enhanced CT showed expansion of left ovary vein from the left renal vein, which twisted into an enhanced round mass in the left ovary area. Finally, a diagnosis of ectopic ovary varices was made, which is secondary to cirrhosis with portal hypertension. Ovary varices should be included as differential diagnoses of 99mTc-RBC bleeding scintigraphy.

Fewer-Angle SPECT/CT Blood Pool Imaging for Infection and Inflammation

A new protocol for rapid SPECT/CT blood pool imaging consisting of fewer image-angle acquisitions (fewer-angle SPECT/CT, or FASpecT/CT) was evaluated for localization of focal sites of soft-tissue inflammation, infection, and osteomyelitis. Methods: Immediately after dynamic flow and standard planar blood pool imaging with ^99mTc-methylene diphosphonate, FASpecT/CT was performed with a dual-head γ-camera consisting of 6 steps over 360°, 12 total images with 30° of separation between angles, and 30 s per image, requiring a total imaging time of approximately 3 min. Images were reconstructed using iterative ordered-subset expectation maximization. Before use in a patient-care setting, various FASpecT/CT acquisition protocols were modeled using a phantom to determine the minimum number of stops and the stop duration required to produce a reliable image. Results: FASpecT/CT images provided excellent 3-dimensional localization of spine osteomyelitis, soft-tissue infection of the foot, and tendonitis of the hand and foot using a 3-min image acquisition time. The FASpecT/CT acquisition protocol required 1.3-3.5 min, including camera movement time. This was a reduction of 72%-90% from the time required for the standard 60-angle, 20-s SPECT/CT acquisition. Conclusion: The ability of FASpecT/CT blood pool images to help localize focal sites of hyperemia and inflammation can increase exam sensitivity and specificity. Additionally, using a FASpecT/CT protocol decreases imaging time by up to 90%.

Incidental Detection of Pancreatic Arteriovenous Malformation by 99mTc-RBC SPECT/CT

A patient with multiple episodes of gastrointestinal bleeding underwent Tc-labeled red blood cell scintigraphy to detect the source of bleeding, which showed a focally increased activity in the upper midabdomen. SPECT/CT demonstrated that the activity was located in the pancreatic head. Angiography confirmed the diagnosis of pancreatic arteriovenous malformation. After transarterial embolization therapy, the patient no longer had bleeding episode. Based on the present case, pancreatic arteriovenous malformation should be included as differential diagnosis during Tc-red blood cell scintigraphy.