Usefulness of Topically Applied Sensors to Assess the Quality of 18F-FDG Injections and Validation Against Dynamic Positron Emission Tomography (PET) Images

Abstract

Background: Infiltrations of 18F-fluorodeoxyglucose (FDG) injections affect positron emission tomography/computed tomography (PET/CT) image quality and quantification. A device using scintillation sensors (Lucerno Dynamics, Cary, NC) provides dynamic measurements acquired during FDG uptake to identify and characterize radioactivity near the injection site prior to patient imaging. Our aim was to compare sensor measurements against dynamic PET image acquisition, our proposed reference in assessing injection quality during the uptake period.Methods: Subjects undergoing routine FDG PET/CT imaging were eligible for this Institutional Review Board approved prospective study. After providing informed consent, subjects had sensors topically placed on their arms. FDG was injected into subjects' veins directly on the PET imaging table. Dynamic images of the injection site were acquired during 45 min of the uptake period. These dynamic image acquisitions and subjects' routine standard static images were evaluated by nuclear medicine physicians for abnormal FDG accumulation near the injection site. Sensor measurements were interpreted independently by Lucerno staff. Dynamic image acquisition interpretation results were compared to the sensor measurement interpretations and to static image interpretations.Results: Twenty-four subjects were consented and enrolled. Data from 21 subjects were gathered. During dynamic image acquisition review, physicians interpreted 4 subjects with no FDG accumulation at the injection site, whereas 17 showed evidence of accumulation. In 10 of the 17 cases that showed FDG accumulation, the FDG presence at the injection site resolved completely during uptake corresponding to venous stasis, the temporary sequestration of blood from circulation. Static image interpretation agreed with dynamic images interpretation in 11/21 (52%) subjects. Sensor measurement interpretations agreed with the dynamic images interpretations in 18/21 (86%) subjects.Conclusions: Sensor measurements can be an effective way to identify and characterize infiltrations and venous stasis. Comparable to an infiltration, venous stasis may produce spurious and clinically meaningful measurement bias and possibly even scan misinterpretation. Since the quality and quantification of PET/CT studies are of clinical importance, sensor measurements acquired during the FDG uptake may prove to be a useful quality control measure to reduce infiltration rates and potentially improve patient care.Registration: Clinicaltrials.gov, Identifier: NCT03041090

Topical Sensor for the Assessment of Injection Quality for 18F-FDG, 68Ga-PSMA and 68Ga-DOTATATE Positron Emission Tomography

“…Clinically, PET and SUV, traditionally for 18F-FDG and now also for 68Ga-PSMA and 68Ga-DOTATATE, require pharmacokinetic assumptions including predictable dose delivery. Extravasation or infiltration occurs when the dose, or part thereof, is administered outside the venous system [2][3][4]. Partial extravasation of the intravenous (IV) dose administration undermines predictability of dose delivery and potentially the accuracy of SUV calculations [2].…”

“…Partial extravasation of the intravenous (IV) dose administration undermines predictability of dose delivery and potentially the accuracy of SUV calculations [2]. The dose administration should be a bolus over approximately 1 minute [3]. The subsequent uptake period varies from 45 to 60 minutes but for accurate SUV consistency of timing is required.…”

“…Partial extravasation, even with complete resolution during the uptake period, changes the kinetics into the tumour; rendering the SUV less accurate. The decreased activity imaged and the trickle effect into the vascular space associated with extravasated injections can degrade overall image quality [3]. The impact of partial extravasation on image quality and quantitation depends on pharmacokinetics of the infiltration: the proportion extravasated, the proportion and rate of any dose that re-enters circulation relative to the imaging time, and the proportion that does not migrate from the extravasated site within the effective imaging window [4].…”

“…Although an indication of dose extravasation may include pain or swelling at the site of injection, visual evaluation of images post-PET procedure is perhaps the most common approach. Because the injection site may be outside the field of view with whole-body PET performed typically with the arms hyperextended above the head, this method is not always accurate [3]. Consequently, the studies outlined previously are likely to underestimate extravasation rates.…”

Quality Improvement Initiatives to Assess and Improve PET/CT Injection Infiltration Rates at Multiple Centers

“…Furthermore, during PET/CT image interpretation, the injection site is often outside the imaging field of view (8). Detection is further hindered when the injection site is within the imaging field of view but the infiltration has resolved completely, leaving no visible evidence (9). There are also few published data on PET/CT radiotracer injection infiltration rates.…”