Seeing the big picture: The importance of reviewing the entire field of view in Myocardial Perfusion Imaging and the role of the Nuclear Medicine Technologist

3002 Objectives: In nuclear medicine, large field of view gamma cameras are typically utilized when imaging relatively small areas of interest. In Myocardial Perfusion Imaging (MPI), the area of interest is generally only in the cardiac activity. However, due to the field of view (FOV) size and the excretion of tracer through both the urinary and gastrointestinal pathways, unusual patterns of uptake may be seen that, if addressed, could be important for patient management. This research reviewed a single case study in which a technologist noticed unusual displacement of the urinary bladder during a MPI which required further investigation. Methods: A patient was referred for a Nuclear Medicine Stress Test for dyspnea and right leg pain after walking more than two blocks. Patient was injected with 8.3 millicuries (mCi) Technetium 99m (Tc-99m) Sestamibi and 30 minutes later underwent rest single photon emission tomography (SPECT) using a large FOV gamma camera (53.3 x 38.7cm detector dimensions), equipped with parallel hole, low energy, high resolution collimation. No unusual uptake pattern was noticed during rest SPECT. Patient then underwent a pharmacologic stress test and 30 minutes after intravenous injection of 31.7 mCi Tc- 99m Sestamibi, gated SPECT images were acquired. After reviewing the stress images, the technologist noticed unusual displacement of the urinary bladder to the left, which was now visible due to urinary excretion of the radiotracer. Before releasing patient, the Nuclear Medicine Technologist (NMT) consulted with the Nuclear Medicine Physician, who agreed SPECT imaging with computed tomography (CT) of the abdomen and pelvis was warranted to further characterize the finding. Results: Cardiac SPECT imaging showed no evidence of ischemia.SPECT/CT of the abdomen and pelvis demonstrated deviation of the urinary bladder anteriorly, superiorly, and to the left by a large lipoma in the pelvis (Image 1 and Image 2). Bowel loops were deviated towards the left by the lipoma. The lipoma appeared multilocular with a thin capsule, and measured approximately 10 x 15 x 9 cm. The inferior vena cava and the infrarenal aorta were also deviated to the left, and the right iliac arteries and veins were draped over the lipoma and were stretched anteriorly and to the left of midline. Surgery was consulted, and after dedicated CT imaging (Image 3), initially made the assessment that resection would be too risky given anatomic site of the mass. The mass subsequently exhibited stability with unchanged size on serial CT imaging. However, because the patient experienced increasing right leg and groin pain, with worsening claudication, it was later resected. Dedicated CT imaging was completed after resection (Image 4). There were no untoward surgical complications and biopsy of mass confirmed a benign lipoma. Conclusion: The NMT can have a tremendous impact in exploring possible incidental findings in nuclear imaging. The NMT, in many clinical imaging units, is the last quality control check prior to the patient being released after exam completion. With careful review of the entire imaging FOV, an NMT can help identify possible incidental findings that can be explored prior to the patient leaving the department. This, as in the case described above, can lead to profound changes in patient management and a more expedited process for addressing those findings. For these reasons, it is important that the entire FOV, as well as all images acquired, be carefully reviewed by the NMT prior to releasing patients as part of a thorough workflow. Image 1. Anterior view of abdomen pelvis from SPECT imaging Image 2. Coronal slice showing fused SPECT/CT imaging Image 3. Dedicated CT abdomen/pelvis showing extent of lipoma pre-resection (coronal slice) Image 4. Dedicated CT post-resection (coronal slice)