Texture Analysis in [\({}^{18}\)F]-Fluciclovine PET/CT Aids to Detect Prostate Cancer Biochemical Relapse: Report of a Preliminary Experience  
[PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; et al. Texture Analysis in [\({}^{18}\)F]-Fluciclovine PET/CT Aids to Detect Prostate Cancer Biochemical Relapse: Report of a Preliminary Experience. April. 2024, 14, 3469. +
Footnote †: These authors contributed equally to this work. antigen (PSA) to pursue precision medicine in order to predict the right treatment for the right patient [5]. First-order features describe individual voxels values, not accounting for spatial relationships between voxels. They report size, shape, and count density-; mean, median, max, and min intensity, and their skewness, kurtosis, uniformity, and randomness. Second-order textural features group voxels with similar statistics and are useful for measuring tumor heterogeneity. GreyThe Gray-Level Co-occurrence Matrix (GLCM) and Gray-level Run Length Metrix (GLRLM), respectively, account for the spatial relationships of pairs of pixels or voxels with predefined gray-level intensities and the spatial distribution of runs of consecutive pixels with the same gray level. Higher-order statistics search for pattern repetitions in the data [1; 6; 7]. Collecting radiomic features (RFs) requires several discrete steps, including either image acquisition, which has to be standardized at intra- and inter-institutional levels; the segmentation of the volume of interest (usually operator-dependent and therefore representing a critical phase); or the mathematical extraction of quantitative descriptors (statistical outputs) [2; 4]. When extracted from functional imaging, namely positron emission tomography (PET) scans, these features signify aspects of radiotracer intensity (concentration), heterogeneity, and shape within the tumor, reflecting biological characteristics with potential value in the prediction of disease progression and aggressiveness [8; 9]. Prostate cancer (PCA) biochemical recurrence (BCR) is detected early by a progressive increase in PSA serum levels over time in spite of castrate testosterone levels [10; 11]. Specifically, BCR occurs in 20-40% of PCa patients after radical prostatectomy (RP) and in 30-50% of cases after radiotherapy (RT) within ten years [12]. Recurrence of prostate disease with metastatic disease occurs in one-third of men who experience BCR within 15 years of RP. Nonetheless, once BCR occurs, the right therapeutic approach depends on whether the disease is localized or disseminated, and functional imaging may address the right treatment. Conventional imaging, such as bone scans, computed tomography (CT), and magnetic resonance (MR), may fail to accurately assess the extent of recurrent disease, whilst eventual extrapelvic disease excludes patients from salvage radiation therapy [13; 14]. [18]F]Flucicolvine (anti-1-amino-3-F18-fluorocyclobutane-1-carboxylic-acid, i.e., [18]F]FACBC) is a radiopharmaceutical that was recently approved by the US FDA (2016) and EMA (2018) for use in cases of biochemical relapse in prostate cancer. [18]F]FACBC [15] is a radiolabeled analog of levorotatory leucine, taken up via the human L-type amino acid transporter (LAT) and alanine-serine-cysteine transporter systems (ASCT2), which are overexpressed in protein-synthetizing tissues and in many carcinomas, including prostate cancer [16]. Once in the cell, [18]F]FACBC uses the same channel to exit unmodified, peaking in pathologic prostate tumors and physiologic pancreas tissue between 4 and 10 min after i.v. injection, decreasing within 15 min, progressively accumulating in muscles and red marrow. Minimal to no activity accumulates in the bladder, which rarely interferes with deep pelvis images examination. PET imaging to assess PCa relapse, therefore, begins 3-5 min after radiotracer injection, caudal to cranial.