PT  - JOURNAL ARTICLE
AU  - Ashley Meyer
AU  - Zachary Higgins
AU  - Ann Packard
AU  - Derek Johnson
TI  - Importance of Injection Site Image in DaTscans
DP  - 2021 May 01
TA  - Journal of Nuclear Medicine
PG  - 156--156
VI  - 62
IP  - supplement 1
4099  - http://jnm.snmjournals.org/content/62/supplement_1/156.short
4100  - http://jnm.snmjournals.org/content/62/supplement_1/156.full
SO  - J Nucl Med2021 May 01; 62
AB  - 156Introduction: At our institution, we routinely acquire planar images of the injection site in patients undergoing [123I]Ioflupane brain SPECT imaging (DaTscan) in order to identify significant radiotracer deposition in the arm related to infiltration. However, it is unknown whether tracer deposition in the arm is associated with lower diagnostic quality of the DaTscan brain images. This information is important in order to determine whether injection site images add value and should continue, or if they could be reasonably omitted to simplify DaTscan workflow. Further, some new SPECT-CT scanners (i.e. the Veriton system from Spectrum Dynamics) do not perform planar imaging and if injection site imaging is necessary these may be less suitable for use in DaTscans. Methods: We conducted a single-institution retrospective study to evaluate the yield of injection site imaging in patients undergoing DaTscan for evaluation of possible parkinsonism. After IRB approval, study images from 200 consecutive DaTscans were reviewed to identify cases with visible uptake at the injection site. Any cases with visible uptake were matched to cases without injection site uptake performed the same or next clinic day. These studies were then rated by two fellowship-trained nuclear medicine radiologists and rated as being diagnostic quality (Y/N) as well as being different or equal in subjective visual quality. Results: Images from 200 DaTscans were reviewed, 185 of which included planar imaging of the injection site. Of these, no activity was seen in 171/185 (92.4%), and some degree of injection-site activity was observed in 14/185 (7.6%). In all 14 cases the associated brain SPECT images were considered diagnostic quality. In 4 cases the brain images of the study with injection site activity and the matched control study were considered equal in quality. Of the 10 studies that differed in subjective quality, they were evenly split (5 each) between favoring the studies with and without injection site activity. Of note, the single study that was judged to be of the lowest quality showed injection site uptake. Conclusions: Overall, almost all the arm views reviewed for this study show no activity around the injection site. Even with activity at the injection site, all of the brain scans were diagnostic and almost all were of good quality. DaTscan quality does depend on how well the dose enters the vein. More than likely, an image will appear normal if there is only a small amount of activity in the injection site. If most of the dose was infiltrated, leaving a lot of activity in the arm, this will affect the quality of the brain image. It would make sense to continue to acquire the arm view, if feasible, considering it has no cost to the patient and is only a short acquisition. If a camera does not have planar imaging capabilities, and therefore, cannot acquire an arm view, the quality of the study is unlikely to be impacted. Our study data indicates that activity at the injection site rarely causes a non-diagnostic image.