Fewer Angle SPECT/CT (FASpecT/CT) Blood Pool Imaging for Infection and Inflammation

Abstract

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