TY - JOUR T1 - <strong>The Role of NAC FDG-PET/CT in Detecting Cutaneous Lesions</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 2707 LP - 2707 VL - 63 IS - supplement 2 AU - Elysia McDonald AU - Babak Saboury AU - Mona-Elisabeth Revheim AU - Abass Alavi Y1 - 2022/06/01 UR - http://jnm.snmjournals.org/content/63/supplement_2/2707.abstract N2 - 2707 Introduction: 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is highly sensitive for detection of cutaneous lesions with elevated metabolic activity, such as aggressive cancers or significant inflammation. While FDG-PET/CT is regarded the gold-standard for detection of malignant lesions, it has been criticized for its lower sensitivity for detection of low metabolic activity cutaneous lesions, such as low-grade skin cancers and psoriatic plaques. Even though the European Society for Medical Oncology recommends the routine use of FDG-PET/CT in staging high-grade cutaneous lesions, FDG-PET/CT is not often performed in patients with low-grade cutaneous cancers or inflammatory skin conditions due to its lower specificity for these lesions. Attenuation correction (AC) of PET images is performed to correct image distortion that may occur during image acquisition. However, AC may introduce artifacts and reduce the contrast of superficial lesions making them more difficult to detect. Studies on the use of FDG-PET/CT for detection of extracutaneous malignancies have shown that analysis of nonattenuation corrected (NAC) images is essential so as not overlook lesions less visible in AC images. This raises the question of whether NAC analysis may improve the sensitivity of FDG-PET/CT for detection of cutaneous lesions. The goal of this scoping review is to quantify the extent of research that has been performed on the utility of NAC FDG-PET/CT in detecting cutaneous lesions, and to explore whether NAC scan analysis may impact the accuracy of FDG-PET/CT in detecting cutaneous lesions.Methods: A scoping review was performed using the PubMed database. The keywords used in the search were: ((non-attenuation corrected) OR (nonattenuation corrected)) AND (positron emission tomography). This search generated 80 papers. Results were filtered to include only clinical studies that utilized NAC PET/CT image analysis in the evaluation of cutaneous lesions. Three papers remained for review after filtering the search. Results: A search of the literature revealed that very few studies have been performed investigating the impact of NAC image analysis on sensitivity of FDG-PET/CT for cutaneous lesions. Of the three studies this scoping review yielded, one study evaluated the use of NAC FDG-PET/CT in patient with primary cutaneous lymphoma (PCL), and the other two studies evaluated NAC FDG-PET/CT in psoriasis patients. The study on PCL concluded that NAC images are superior to AC images for the detection of cutaneous lesions, while AC images were superior in their ability to detect deeper lesions. The studies evaluating patients with moderate-to-severe psoriasis reported that some cutaneous lesions display reduced FDG uptake in AC images, making them hard to identify. However, identification of these lesions in NAC scans ensured that these lesions were not overlooked during FDG-PET/CT analysis. Conclusions: All three studies showed that cutaneous lesions were easier to identify in the NAC scan due to increased contrast. These studies conclude that it is vital to analyze NAC when using FDG-PET/CT for detection of cutaneous lesions, so as not to overlook lesions that display low FDG avidity in the AC scan. Current research suggests routine analysis of NAC scans to evaluate patients with cutaneous lesions may improve the sensitivity of FDG-PET/CT for lesions with low metabolic activity. It is essential that cutaneous cancers are correctly staged, and that extent of disease in patients with moderate-to-severe psoriasis be properly estimated, to secure the appropriate clinical interventions that will allow for best outcome. Further studies must be performed investigating whether NAC image analysis may improve the sensitivity of FDG-PET/CT for cutaneous lesions. If this is the case, the utility of FDG-PET/CT may be expanded beyond its limited use, enabling more accurate disease staging in patients with skin cancers and inflammatory cutaneous conditions. ER -